zic.c

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/* Compile .zi time zone data into TZif binary files.  */
 
/*
 * This file is in the public domain, so clarified as of
 * 2006-07-17 by Arthur David Olson.
 *
 * IDENTIFICATION
 *    src/timezone/zic.c
 */
 
#include "postgres_fe.h"
 
#include <fcntl.h>
#include <grp.h>
#include <pwd.h>
#include <signal.h>
#include <sys/stat.h>
#include <time.h>
 
#include "pg_getopt.h"
 
#include "private.h"
#include "tzfile.h"
 
#ifndef O_BINARY
#define O_BINARY 0              /* MS-Windows */
#endif
 
typedef int_fast64_t zic_t;
static zic_t const
            ZIC_MIN = INT_FAST64_MIN,
            ZIC_MAX = INT_FAST64_MAX,
            ZIC32_MIN = -1 - (zic_t) TWO_31_MINUS_1,
            ZIC32_MAX = TWO_31_MINUS_1;
#define SCNdZIC SCNdFAST64
 
#ifndef ZIC_MAX_ABBR_LEN_WO_WARN
#define ZIC_MAX_ABBR_LEN_WO_WARN 6
#endif                          /* !defined ZIC_MAX_ABBR_LEN_WO_WARN */
 
/* Minimum and maximum years, assuming signed 32-bit pg_time_t.  */
enum
{
YEAR_32BIT_MIN = 1901, YEAR_32BIT_MAX = 2038};
 
/* An upper bound on how much a format might grow due to concatenation.  */
enum
{
FORMAT_LEN_GROWTH_BOUND = 5};
 
/* All file permission bits.  */
#define ALL_PERMS (S_IRWXU | S_IRWXG | S_IRWXO)
 
/* Troublesome file permission bits.  */
#define TROUBLE_PERMS (S_IWGRP | S_IWOTH)
 
/*
 * File permission bits for making directories.
 * The umask modifies these bits.
 */
#define MKDIR_PERMS (ALL_PERMS & ~TROUBLE_PERMS)
 
/*
 * File permission bits for making regular files.
 * The umask modifies these bits.
 */
#define CREAT_PERMS (MKDIR_PERMS & ~(S_IXUSR | S_IXGRP | S_IXOTH))
static mode_t creat_perms = CREAT_PERMS;
 
static gid_t const no_gid = -1;
static uid_t const no_uid = -1;
static gid_t output_group = -1;
static uid_t output_owner = -1;
#ifndef GID_T_MAX
#define GID_T_MAX MAXVAL(gid_t, TYPE_BIT(gid_t))
#endif
#ifndef UID_T_MAX
#define UID_T_MAX MAXVAL(uid_t, TYPE_BIT(uid_t))
#endif
 
/*
 * The minimum alignment of a type, for pre-C23 platforms.
 * The __SUNPRO_C test is because Oracle Developer Studio 12.6 lacks
 * <stdalign.h> even though __STDC_VERSION__ == 201112.
 */
#if __STDC_VERSION__ < 201112 || defined __SUNPRO_C
#define alignof(type) offsetof(struct { char a; type b; }, b)
#elif __STDC_VERSION__ < 202311
#include <stdalign.h>
#endif
 
/* The name used for the file implementing the obsolete -p option.  */
#ifndef TZDEFRULES
#define TZDEFRULES "posixrules"
#endif
 
/* The maximum length of a text line, including the trailing newline.  */
#ifndef _POSIX2_LINE_MAX
#define _POSIX2_LINE_MAX 2048
#endif
 
/*
 * The type for line numbers.  Use PRIdMAX to format them; formerly
 * there was also "#define PRIdLINENO PRIdMAX" and formats used
 * PRIdLINENO, but xgettext cannot grok that.
 */
typedef intmax_t lineno_t;
 
struct rule
{
    int         r_filenum;
    lineno_t    r_linenum;
    const char *r_name;
 
    zic_t       r_loyear;       /* for example, 1986 */
    zic_t       r_hiyear;       /* for example, 1986 */
    bool        r_hiwasnum;
 
    int         r_month;        /* 0..11 */
 
    int         r_dycode;       /* see below */
    int         r_dayofmonth;
    int         r_wday;
 
    zic_t       r_tod;          /* time from midnight */
    bool        r_todisstd;     /* is r_tod standard time? */
    bool        r_todisut;      /* is r_tod UT? */
    bool        r_isdst;        /* is this daylight saving time? */
    zic_t       r_save;         /* offset from standard time */
    const char *r_abbrvar;      /* variable part of abbreviation */
 
    bool        r_todo;         /* a rule to do (used in outzone) */
    zic_t       r_temp;         /* used in outzone */
};
 
/*
 * r_dycode r_dayofmonth    r_wday
 */
enum
{
    DC_DOM,                     /* 1..31 */ /* unused */
    DC_DOWGEQ,                  /* 1..31 */ /* 0..6 (Sun..Sat) */
    DC_DOWLEQ                   /* 1..31 */ /* 0..6 (Sun..Sat) */
};
 
struct zone
{
    int         z_filenum;
    lineno_t    z_linenum;
 
    const char *z_name;
    zic_t       z_stdoff;
    char       *z_rule;
    const char *z_format;
    char        z_format_specifier;
 
    bool        z_isdst;
    zic_t       z_save;
 
    struct rule *z_rules;
    ptrdiff_t   z_nrules;
 
    struct rule z_untilrule;
    zic_t       z_untiltime;
};
 
#ifndef AT_SYMLINK_FOLLOW
#define linkat(targetdir, target, linknamedir, linkname, flag) \
   (errno = ENOTSUP, -1)
#endif
 
static void verror(const char *const string, va_list args) pg_attribute_printf(1, 0);
static void error(const char *const string, ...) pg_attribute_printf(1, 2);
static void warning(const char *const string, ...) pg_attribute_printf(1, 2);
static int  addabbr(char chs[TZ_MAX_CHARS], int *pnchs, char const *abbr);
static void addtt(zic_t starttime, int type);
static int  addtype(zic_t utoff, char const *abbr,
                    bool isdst, bool ttisstd, bool ttisut);
static void adjleap(void);
static void associate(void);
static void checkabbr(char const *string);
static void check_for_signal(void);
static void dolink(char const *target, char const *linkname, bool staysymlink);
static int  getfields(char *cp, char **array, int arrayelts);
static zic_t gethms(const char *string, const char *errstring);
static zic_t getsave(char *field, bool *isdst);
static void inexpires(char **fields, int nfields);
static void infile(int fnum, char const *name);
static void inleap(char **fields, int nfields);
static void inlink(char **fields, int nfields);
static void inrule(char **fields, int nfields);
static bool inzcont(char **fields, int nfields);
static bool inzone(char **fields, int nfields);
static bool inzsub(char **fields, int nfields, bool iscont);
static bool is_alpha(char a);
static int  itssymlink(char const *name, int *cache);
static void leapadd(zic_t t, int correction, int rolling);
static char lowerit(char a);
static void mkdirs(char const *argname, bool ancestors);
static zic_t oadd(zic_t t1, zic_t t2);
static zic_t omul(zic_t t1, zic_t t2);
static void outzone(const struct zone *zpfirst, ptrdiff_t zonecount);
static zic_t rpytime(const struct rule *rp, zic_t wantedy);
static bool rulesub(struct rule *rp,
                    const char *loyearp, const char *hiyearp,
                    const char *typep, const char *monthp,
                    const char *dayp, const char *timep);
static zic_t tadd(zic_t t1, zic_t t2);
 
/* Is C an ASCII digit?  */
static bool
is_digit(char c)
{
    return '0' <= c && c <= '9';
}
 
/* Bound on length of what %z can expand to.  */
enum
{
PERCENT_Z_LEN_BOUND = sizeof "+995959" - 1};
 
static int  charcnt;
static bool errors;
static bool warnings;
static int  filenum;
static ptrdiff_t leapcnt;
static ptrdiff_t leap_alloc;
static bool leapseen;
static zic_t leapminyear;
static zic_t leapmaxyear;
static lineno_t linenum;
static int  max_abbrvar_len = PERCENT_Z_LEN_BOUND;
static int  max_format_len;
static zic_t max_year;
static zic_t min_year;
static bool noise;
static bool print_abbrevs;
static zic_t print_cutoff;
static bool skip_mkdir;
static int  rfilenum;
static lineno_t rlinenum;
static const char *progname;
static char const *leapsec;
static char *const *main_argv;
static ptrdiff_t timecnt;
static ptrdiff_t timecnt_alloc;
static int  typecnt;
static int  unspecifiedtype;
 
/*
 * Line codes.
 */
 
enum
{
    LC_RULE,
    LC_ZONE,
    LC_LINK,
    LC_LEAP,
    LC_EXPIRES
};
 
/*
 * Which fields are which on a Zone line.
 */
 
enum
{
    ZF_NAME = 1,
    ZF_STDOFF,
    ZF_RULE,
    ZF_FORMAT,
    ZF_TILYEAR,
    ZF_TILMONTH,
    ZF_TILDAY,
    ZF_TILTIME,
    ZONE_MAXFIELDS,
    ZONE_MINFIELDS = ZF_TILYEAR
};
 
/*
 * Which fields are which on a Zone continuation line.
 */
 
enum
{
    ZFC_STDOFF,
    ZFC_RULE,
    ZFC_FORMAT,
    ZFC_TILYEAR,
    ZFC_TILMONTH,
    ZFC_TILDAY,
    ZFC_TILTIME,
    ZONEC_MAXFIELDS,
    ZONEC_MINFIELDS = ZFC_TILYEAR
};
 
/*
 * Which files are which on a Rule line.
 */
 
enum
{
    RF_NAME = 1,
    RF_LOYEAR,
    RF_HIYEAR,
    RF_COMMAND,
    RF_MONTH,
    RF_DAY,
    RF_TOD,
    RF_SAVE,
    RF_ABBRVAR,
    RULE_FIELDS
};
 
/*
 * Which fields are which on a Link line.
 */
 
enum
{
    LF_TARGET = 1,
    LF_LINKNAME,
    LINK_FIELDS
};
 
/*
 * Which fields are which on a Leap line.
 */
 
enum
{
    LP_YEAR = 1,
    LP_MONTH,
    LP_DAY,
    LP_TIME,
    LP_CORR,
    LP_ROLL,
    LEAP_FIELDS,
 
    /*
     * Expires lines are like Leap lines, except without CORR and ROLL fields.
     */
    EXPIRES_FIELDS = LP_TIME + 1
};
 
/*
 * The maximum number of fields on any of the above lines.
 * (The "+"s pacify gcc -Wenum-compare.)
 */
enum
{
    MAX_FIELDS = max(max(+RULE_FIELDS, +LINK_FIELDS),
                     max(+LEAP_FIELDS, +EXPIRES_FIELDS))
};
 
/*
 * Year synonyms.
 */
 
enum
{
    YR_MINIMUM,                 /* "minimum" is for backward compatibility
                                 * only */
    YR_MAXIMUM,
    YR_ONLY
};
 
static struct rule *rules;
static ptrdiff_t nrules;        /* number of rules */
static ptrdiff_t nrules_alloc;
 
static struct zone *zones;
static ptrdiff_t nzones;        /* number of zones */
static ptrdiff_t nzones_alloc;
 
struct link
{
    int         l_filenum;
    lineno_t    l_linenum;
    const char *l_target;
    const char *l_linkname;
};
 
static struct link *links;
static ptrdiff_t nlinks;
static ptrdiff_t nlinks_alloc;
 
struct lookup
{
    const char *l_word;
    const int   l_value;
};
 
static struct lookup const *byword(const char *word,
                                   const struct lookup *table);
 
static struct lookup const zi_line_codes[] = {
    {"Rule", LC_RULE},
    {"Zone", LC_ZONE},
    {"Link", LC_LINK},
    {NULL, 0}
};
static struct lookup const leap_line_codes[] = {
    {"Leap", LC_LEAP},
    {"Expires", LC_EXPIRES},
    {NULL, 0}
};
 
static struct lookup const mon_names[] = {
    {"January", TM_JANUARY},
    {"February", TM_FEBRUARY},
    {"March", TM_MARCH},
    {"April", TM_APRIL},
    {"May", TM_MAY},
    {"June", TM_JUNE},
    {"July", TM_JULY},
    {"August", TM_AUGUST},
    {"September", TM_SEPTEMBER},
    {"October", TM_OCTOBER},
    {"November", TM_NOVEMBER},
    {"December", TM_DECEMBER},
    {NULL, 0}
};
 
static struct lookup const wday_names[] = {
    {"Sunday", TM_SUNDAY},
    {"Monday", TM_MONDAY},
    {"Tuesday", TM_TUESDAY},
    {"Wednesday", TM_WEDNESDAY},
    {"Thursday", TM_THURSDAY},
    {"Friday", TM_FRIDAY},
    {"Saturday", TM_SATURDAY},
    {NULL, 0}
};
 
static struct lookup const lasts[] = {
    {"last-Sunday", TM_SUNDAY},
    {"last-Monday", TM_MONDAY},
    {"last-Tuesday", TM_TUESDAY},
    {"last-Wednesday", TM_WEDNESDAY},
    {"last-Thursday", TM_THURSDAY},
    {"last-Friday", TM_FRIDAY},
    {"last-Saturday", TM_SATURDAY},
    {NULL, 0}
};
 
static struct lookup const begin_years[] = {
    {"minimum", YR_MINIMUM},
    {NULL, 0}
};
 
static struct lookup const end_years[] = {
    {"maximum", YR_MAXIMUM},
    {"only", YR_ONLY},
    {NULL, 0}
};
 
static struct lookup const leap_types[] = {
    {"Rolling", true},
    {"Stationary", false},
    {NULL, 0}
};
 
static const int len_months[2][MONSPERYEAR] = {
    {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
    {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}
};
 
static const int len_years[2] = {
    DAYSPERNYEAR, DAYSPERLYEAR
};
 
static struct attype
{
    zic_t       at;
    bool        dontmerge;
    unsigned char type;
}          *attypes;
static zic_t utoffs[TZ_MAX_TYPES];
static char isdsts[TZ_MAX_TYPES];
static unsigned char desigidx[TZ_MAX_TYPES];
static bool ttisstds[TZ_MAX_TYPES];
static bool ttisuts[TZ_MAX_TYPES];
static char chars[TZ_MAX_CHARS];
static struct
{
    zic_t       trans;
    zic_t       corr;
    char        roll;
}          *leap;
 
/*
 * Memory allocation.
 */
 
ATTRIBUTE_NORETURN static void
memory_exhausted(const char *msg)
{
    fprintf(stderr, _("%s: Memory exhausted: %s\n"), progname, msg);
    exit(EXIT_FAILURE);
}
 
ATTRIBUTE_NORETURN static void
size_overflow(void)
{
    memory_exhausted(_("size overflow"));
}
 
ATTRIBUTE_PURE_114833_HACK
static ptrdiff_t
size_sum(size_t a, size_t b)
{
#ifdef ckd_add
    ptrdiff_t   sum;
 
    if (!ckd_add(&sum, a, b) && sum <= INDEX_MAX)
        return sum;
#else
    if (a <= INDEX_MAX && b <= INDEX_MAX - a)
        return a + b;
#endif
    size_overflow();
}
 
ATTRIBUTE_PURE_114833_HACK
static ptrdiff_t
size_product(ptrdiff_t nitems, ptrdiff_t itemsize)
{
#ifdef ckd_mul
    ptrdiff_t   product;
 
    if (!ckd_mul(&product, nitems, itemsize) && product <= INDEX_MAX)
        return product;
#else
    ptrdiff_t   nitems_max = INDEX_MAX / itemsize;
 
    if (nitems <= nitems_max)
        return nitems * itemsize;
#endif
    size_overflow();
}
 
ATTRIBUTE_PURE_114833_HACK
static ptrdiff_t
align_to(ptrdiff_t size, ptrdiff_t alignment)
{
    ptrdiff_t   lo_bits = alignment - 1,
                sum = size_sum(size, lo_bits);
 
    return sum & ~lo_bits;
}
 
static void *
memcheck(void *ptr)
{
    if (ptr == NULL)
        memory_exhausted(strerror(errno));
    return ptr;
}
 
static void *
xmalloc(size_t size)
{
    return memcheck(malloc(size));
}
 
static void *
xrealloc(void *ptr, size_t size)
{
    return memcheck(realloc(ptr, size));
}
 
static char *
xstrdup(char const *str)
{
    return memcheck(strdup(str));
}
 
static ptrdiff_t
grow_nitems_alloc(ptrdiff_t *nitems_alloc, ptrdiff_t itemsize)
{
    ptrdiff_t   addend = (*nitems_alloc >> 1) + 1;
#if defined ckd_add && defined ckd_mul
    ptrdiff_t   product;
 
    if (!ckd_add(nitems_alloc, *nitems_alloc, addend)
        && !ckd_mul(&product, *nitems_alloc, itemsize) && product <= INDEX_MAX)
        return product;
#else
    if (*nitems_alloc <= ((INDEX_MAX - 1) / 3 * 2) / itemsize)
    {
        *nitems_alloc += addend;
        return *nitems_alloc * itemsize;
    }
#endif
    memory_exhausted(_("integer overflow"));
}
 
static void *
growalloc(void *ptr, ptrdiff_t itemsize, ptrdiff_t nitems,
          ptrdiff_t *nitems_alloc)
{
    return (nitems < *nitems_alloc
            ? ptr
            : xrealloc(ptr, grow_nitems_alloc(nitems_alloc, itemsize)));
}
 
/*
 * Error handling.
 */
 
/*
 * In most of the code, an input file name is represented by its index
 * into the main argument vector, except that LEAPSEC_FILENUM stands
 * for leapsec and COMMAND_LINE_FILENUM stands for the command line.
 */
enum
{
LEAPSEC_FILENUM = -2, COMMAND_LINE_FILENUM = -1};
 
/* Return the name of the Ith input file, for diagnostics.  */
static char const *
filename(int i)
{
    if (i == COMMAND_LINE_FILENUM)
        return _("command line");
    else
    {
        char const *fname = i == LEAPSEC_FILENUM ? leapsec : main_argv[i];
 
        return strcmp(fname, "-") == 0 ? _("standard input") : fname;
    }
}
 
static void
eats(int fnum, lineno_t num, int rfnum, lineno_t rnum)
{
    filenum = fnum;
    linenum = num;
    rfilenum = rfnum;
    rlinenum = rnum;
}
 
static void
eat(int fnum, lineno_t num)
{
    eats(fnum, num, 0, -1);
}
 
static void
verror(const char *const string, va_list args)
{
    check_for_signal();
 
    /*
     * Match the format of "cc" to allow sh users to zic ... 2>&1 | error -t
     * "*" -v on BSD systems.
     */
    if (filenum)
        fprintf(stderr, _("\"%s\", line %" PRIdMAX ": "),
                filename(filenum), linenum);
    vfprintf(stderr, string, args);
    if (rfilenum)
        fprintf(stderr, _(" (rule from \"%s\", line %" PRIdMAX ")"),
                filename(rfilenum), rlinenum);
    fprintf(stderr, "\n");
}
 
static void
error(const char *const string, ...)
{
    va_list     args;
 
    va_start(args, string);
    verror(string, args);
    va_end(args);
    errors = true;
}
 
static void
warning(const char *const string, ...)
{
    va_list     args;
 
    fprintf(stderr, _("warning: "));
    va_start(args, string);
    verror(string, args);
    va_end(args);
    warnings = true;
}
 
/*
 * Convert ARG, a string in base BASE, to an unsigned long value no
 * greater than MAXVAL.  On failure, diagnose with MSGID and exit.
 */
static unsigned long
arg2num(char const *arg, int base, unsigned long maxval, char const *msgid)
{
    unsigned long n;
    char       *ep;
 
    errno = 0;
    n = strtoul(arg, &ep, base);
    if (ep == arg || *ep || maxval < n || errno)
    {
        fprintf(stderr, _(msgid), progname, arg);
        exit(EXIT_FAILURE);
    }
    return n;
}
 
#ifndef MODE_T_MAX
#define MODE_T_MAX MAXVAL(mode_t, TYPE_BIT(mode_t))
#endif
 
#ifndef HAVE_SETMODE
#if (defined __FreeBSD__ || defined __NetBSD__ || defined __OpenBSD__ \
      || (defined __APPLE__ && defined __MACH__))
#define HAVE_SETMODE 1
#else
#define HAVE_SETMODE 0
#endif
#endif
 
static mode_t const no_mode = -1;
static mode_t output_mode = -1;
 
static mode_t
mode_option(char const *arg)
{
#if HAVE_SETMODE
    void       *set = setmode(arg);
 
    if (set)
    {
        mode_t      mode = getmode(set, CREAT_PERMS);
 
        free(set);
        return mode;
    }
#endif
    return arg2num(arg, 8, min(MODE_T_MAX, ULONG_MAX),
                   N_("%s: -m '%s': invalid mode\n"));
}
 
static int
chmetadata(FILE *stream)
{
#ifndef WIN32
    if (output_owner != no_uid || output_group != no_gid)
    {
        int         r = fchown(fileno(stream), output_owner, output_group);
 
        if (r < 0)
            return r;
    }
    return output_mode == no_mode ? 0 : fchmod(fileno(stream), output_mode);
#else
    return 0;
#endif
}
 
/*
 * Close STREAM.
 * If it had an I/O error, report it against DIR/NAME,
 * remove TEMPNAME if nonnull, and then exit.
 * If TEMPNAME is nonnull, and if requested,
 * change the stream's metadata before closing.
 */
static void
close_file(FILE *stream, char const *dir, char const *name,
           char const *tempname)
{
    char const *e = (ferror(stream) ? _("I/O error")
                     : ((tempname
                         && (fflush(stream) < 0 || chmetadata(stream) < 0))
                        || fclose(stream) < 0)
                     ? strerror(errno) : NULL);
 
    if (e)
    {
        if (name && *name == '/')
            dir = NULL;
        fprintf(stderr, "%s: %s%s%s%s%s\n", progname,
                dir ? dir : "", dir ? "/" : "",
                name ? name : "", name ? ": " : "",
                e);
        if (tempname)
            remove(tempname);
        exit(EXIT_FAILURE);
    }
}
 
ATTRIBUTE_NORETURN static void
duplicate_options(char const *opt)
{
    fprintf(stderr, _("%s: More than one %s option specified\n"), progname, opt);
    exit(EXIT_FAILURE);
}
 
ATTRIBUTE_NORETURN static void
usage(FILE *stream, int status)
{
    fprintf(stream,
            _("%s: usage is %s [ --version ] [ --help ] [ -v ] [ -P ] \\\n"
              "\t[ -b {slim|fat} ] [ -d directory ] [ -D ] \\\n"
              "\t[ -l localtime ] [ -L leapseconds ] [ -m mode ] \\\n"
              "\t[ -p posixrules ] [ -r '[@lo][/@hi]' ] [ -R @hi ] \\\n"
              "\t[ -t localtime-link ] [ -u 'owner[:group]' ] \\\n"
              "\t[ filename ... ]\n\n"
              "Report bugs to %s.\n"),
            progname, progname, PACKAGE_BUGREPORT);
    if (status == EXIT_SUCCESS)
        close_file(stream, NULL, NULL, NULL);
    exit(status);
}
 
static void
group_option(char const *arg)
{
#ifndef WIN32
    if (*arg)
    {
        if (output_group != no_gid)
        {
            fprintf(stderr, _("multiple groups specified"));
            exit(EXIT_FAILURE);
        }
        else
        {
            struct group *gr = getgrnam(arg);
 
            output_group = (gr ? gr->gr_gid
                            : arg2num(arg, 10, min(GID_T_MAX, ULONG_MAX),
                                      N_("%s: invalid group: %s\n")));
        }
    }
#endif
}
 
static void
owner_option(char const *arg)
{
#ifndef WIN32
    if (*arg)
    {
        if (output_owner != no_uid)
        {
            fprintf(stderr, _("multiple owners specified"));
            exit(EXIT_FAILURE);
        }
        else
        {
            struct passwd *pw = getpwnam(arg);
 
            output_owner = (pw ? pw->pw_uid
                            : arg2num(arg, 10, min(UID_T_MAX, ULONG_MAX),
                                      N_("%s: invalid owner: %s\n")));
        }
    }
#endif
}
 
/*
 * If setting owner or group, use temp file permissions that avoid
 * security races before the fchmod at the end.
 */
static void
use_safe_temp_permissions(void)
{
    if (output_owner != no_uid || output_group != no_gid)
    {
 
        /* The mode when done with the file.  */
        mode_t      omode;
 
        if (output_mode == no_mode)
        {
            mode_t      cmask = umask(0);
 
            umask(cmask);
            omode = CREAT_PERMS & ~cmask;
        }
        else
            omode = output_mode;
 
        /*
         * The mode passed to open+O_CREAT.  Do not bother with executable
         * permissions, as they should not be used and this mode is merely a
         * nicety (even a mode of 0 still work).
         */
        creat_perms = ((((omode & (S_IRUSR | S_IRGRP | S_IROTH))
                         == (S_IRUSR | S_IRGRP | S_IROTH))
                        ? S_IRUSR | S_IRGRP | S_IROTH : 0)
                       | (((omode & (S_IWUSR | S_IWGRP | S_IWOTH))
                           == (S_IWUSR | S_IWGRP | S_IWOTH))
                          ? S_IWUSR | S_IWGRP | S_IWOTH : 0));
 
        /*
         * If creat_perms is not the final mode, arrange to run fchmod later,
         * even if -m was not used.
         */
        if (creat_perms != omode)
            output_mode = omode;
    }
}
 
/*
 * Change the working directory to DIR, possibly creating DIR and its
 * ancestors.  After this is done, all files are accessed with names
 * relative to DIR.
 */
static void
change_directory(char const *dir)
{
    if (chdir(dir) != 0)
    {
        int         chdir_errno = errno;
 
        if (chdir_errno == ENOENT)
        {
            mkdirs(dir, false);
            chdir_errno = chdir(dir) == 0 ? 0 : errno;
        }
        if (chdir_errno != 0)
        {
            fprintf(stderr, _("%s: Can't chdir to %s: %s\n"),
                    progname, dir, strerror(chdir_errno));
            exit(EXIT_FAILURE);
        }
    }
}
 
/* Compare the two links A and B, for a stable sort by link name.  */
static int
qsort_linkcmp(void const *a, void const *b)
{
    struct link const *l = a;
    struct link const *m = b;
    int         cmp = strcmp(l->l_linkname, m->l_linkname);
 
    if (cmp)
        return cmp;
 
    /*
     * The link names are the same.  Make the sort stable by comparing file
     * numbers (where subtraction cannot overflow) and possibly line numbers
     * (where it can).
     */
    cmp = l->l_filenum - m->l_filenum;
    if (cmp)
        return cmp;
    return (l->l_linenum > m->l_linenum) - (l->l_linenum < m->l_linenum);
}
 
/* Compare the string KEY to the link B, for bsearch.  */
static int
bsearch_linkcmp(void const *key, void const *b)
{
    struct link const *m = b;
 
    return strcmp(key, m->l_linkname);
}
 
/* Make the links specified by the Link lines.  */
static void
make_links(void)
{
    ptrdiff_t   i,
                j,
                nalinks,
                pass_size;
 
    if (1 < nlinks)
        qsort(links, nlinks, sizeof *links, qsort_linkcmp);
 
    /* Ignore each link superseded by a later link with the same name.  */
    j = 0;
    for (i = 0; i < nlinks; i++)
    {
        while (i + 1 < nlinks
               && strcmp(links[i].l_linkname, links[i + 1].l_linkname) == 0)
            i++;
        links[j++] = links[i];
    }
    nlinks = pass_size = j;
 
    /*
     * Walk through the link array making links.  However, if a link's target
     * has not been made yet, append a copy to the end of the array.  The end
     * of the array will gradually fill up with a small sorted subsequence of
     * not-yet-made links. nalinks counts all the links in the array,
     * including copies. When we reach the copied subsequence, it may still
     * contain a link to a not-yet-made link, so the process repeats. At any
     * given point in time, the link array consists of the following
     * subregions, where 0 <= i <= j <= nalinks and 0 <= nlinks <= nalinks:
     *
     * 0 .. (i - 1): links that either have been made, or have been copied to
     * a later point point in the array (this later point can be in any of the
     * three subregions) i .. (j - 1): not-yet-made links for this pass j ..
     * (nalinks - 1): not-yet-made links that this pass has skipped because
     * they were links to not-yet-made links
     *
     * The first subregion might not be sorted if nlinks < i; the other two
     * subregions are sorted.  This algorithm does not alter entries 0 ..
     * (nlinks - 1), which remain sorted.
     *
     * If there are L links, this algorithm is O(C*L*log(L)) where C is the
     * length of the longest link chain.  Usually C is short (e.g., 3) though
     * its worst-case value is L.
     */
 
    j = nalinks = nlinks;
 
    for (i = 0; i < nalinks; i++)
    {
        struct link *l;
 
        eat(links[i].l_filenum, links[i].l_linenum);
 
        /* If this pass examined all its links, start the next pass.  */
        if (i == j)
        {
            if (nalinks - i == pass_size)
            {
                error(_("\"Link %s %s\" is part of a link cycle"),
                      links[i].l_target, links[i].l_linkname);
                break;
            }
            j = nalinks;
            pass_size = nalinks - i;
        }
 
        /*
         * Diagnose self links, which the cycle detection algorithm would not
         * otherwise catch.
         */
        if (strcmp(links[i].l_target, links[i].l_linkname) == 0)
        {
            error(_("link %s targets itself"), links[i].l_target);
            continue;
        }
 
        /* Make this link unless its target has not been made yet.  */
        l = bsearch(links[i].l_target, &links[i + 1], j - (i + 1),
                    sizeof *links, bsearch_linkcmp);
        if (!l)
            l = bsearch(links[i].l_target, &links[j], nalinks - j,
                        sizeof *links, bsearch_linkcmp);
        if (!l)
            dolink(links[i].l_target, links[i].l_linkname, false);
        else
        {
            /*
             * The link target has not been made yet; copy the link to the
             * end.
             */
            links = growalloc(links, sizeof *links, nalinks, &nlinks_alloc);
            links[nalinks++] = links[i];
        }
 
        if (noise && i < nlinks)
        {
            if (l)
                warning(_("link %s targeting link %s mishandled by pre-2023 zic"),
                        links[i].l_linkname, links[i].l_target);
            else if (bsearch(links[i].l_target, links, nlinks, sizeof *links,
                             bsearch_linkcmp))
                warning(_("link %s targeting link %s"),
                        links[i].l_linkname, links[i].l_target);
        }
        check_for_signal();
    }
}
 
/*
 * Simple signal handling: just set a flag that is checked
 * periodically outside critical sections.  To set up the handler,
 * prefer sigaction if available to close a signal race.
 */
 
static sig_atomic_t got_signal;
 
static void
signal_handler(int sig)
{
#ifndef SA_SIGINFO
    signal(sig, signal_handler);
#endif
    got_signal = sig;
}
 
/* Arrange for SIGINT etc. to be caught by the handler.  */
static void
catch_signals(void)
{
    static int const signals[] = {
#ifdef SIGHUP
        SIGHUP,
#endif
        SIGINT,
#ifdef SIGPIPE
        SIGPIPE,
#endif
        SIGTERM
    };
    size_t      i;
 
    for (i = 0; i < sizeof signals / sizeof signals[0]; i++)
    {
#ifdef SA_SIGINFO
        struct sigaction act0,
                    act;
 
        act.sa_handler = signal_handler;
        sigemptyset(&act.sa_mask);
        act.sa_flags = 0;
        if (sigaction(signals[i], &act, &act0) == 0
            && !(act0.sa_flags & SA_SIGINFO) && act0.sa_handler == SIG_IGN)
        {
            sigaction(signals[i], &act0, NULL);
            got_signal = 0;
        }
#else
        if (signal(signals[i], signal_handler) == SIG_IGN)
        {
            signal(signals[i], SIG_IGN);
            got_signal = 0;
        }
#endif
    }
}
 
/* If a signal has arrived, terminate zic with appropriate status.  */
static void
check_for_signal(void)
{
    int         sig = got_signal;
 
    if (sig)
    {
        signal(sig, SIG_DFL);
        raise(sig);
        abort();                /* A bug in 'raise'.  */
    }
}
 
enum
{
TIME_T_BITS_IN_FILE = 64};
 
/* The minimum and maximum values representable in a TZif file.  */
static zic_t const min_time = MINVAL(zic_t, TIME_T_BITS_IN_FILE);
static zic_t const max_time = MAXVAL(zic_t, TIME_T_BITS_IN_FILE);
 
/*
 * The minimum, and one less than the maximum, values specified by
 * the -r option.  These default to MIN_TIME and MAX_TIME.
 */
static zic_t lo_time = MINVAL(zic_t, TIME_T_BITS_IN_FILE);
static zic_t hi_time = MAXVAL(zic_t, TIME_T_BITS_IN_FILE);
 
/*
 * The time specified by the -R option, defaulting to MIN_TIME;
 * or lo_time, whichever is greater.
 */
static zic_t redundant_time = MINVAL(zic_t, TIME_T_BITS_IN_FILE);
 
/* The time specified by an Expires line, or negative if no such line.  */
static zic_t leapexpires = -1;
 
/*
 * Set the time range of the output to TIMERANGE.
 * Return true if successful.
 */
static bool
timerange_option(char *timerange)
{
    intmax_t    lo = min_time,
                hi = max_time;
    char       *lo_end = timerange,
               *hi_end;
 
    if (*timerange == '@')
    {
        errno = 0;
        lo = strtoimax(timerange + 1, &lo_end, 10);
        if (lo_end == timerange + 1 || (lo == INTMAX_MAX && errno == ERANGE))
            return false;
    }
    hi_end = lo_end;
    if (lo_end[0] == '/' && lo_end[1] == '@')
    {
        errno = 0;
        hi = strtoimax(lo_end + 2, &hi_end, 10);
        if (hi_end == lo_end + 2 || hi == INTMAX_MIN)
            return false;
        hi -= !(hi == INTMAX_MAX && errno == ERANGE);
    }
    if (*hi_end || hi < lo || max_time < lo || hi < min_time)
        return false;
    lo_time = max(lo, min_time);
    hi_time = min(hi, max_time);
    return true;
}
 
/* Generate redundant time stamps up to OPT.  Return true if successful.  */
static bool
redundant_time_option(char *opt)
{
    if (*opt == '@')
    {
        intmax_t    redundant;
        char       *opt_end;
 
        redundant = strtoimax(opt + 1, &opt_end, 10);
        if (opt_end != opt + 1 && !*opt_end)
        {
            redundant_time = max(redundant_time, redundant);
            return true;
        }
    }
    return false;
}
 
static const char *psxrules;
static const char *lcltime;
static const char *directory;
static const char *tzdefault;
 
/* True if DIRECTORY ends in '/'.  */
static bool directory_ends_in_slash;
 
/*
 * -1 if the TZif output file should be slim, 0 if default, 1 if the
 * output should be fat for backward compatibility.  ZIC_BLOAT_DEFAULT
 * determines the default.
 */
static int  bloat;
 
static bool
want_bloat(void)
{
    return 0 <= bloat;
}
 
#ifndef ZIC_BLOAT_DEFAULT
#define ZIC_BLOAT_DEFAULT "slim"
#endif
 
int
main(int argc, char **argv)
{
    int         c,
                k;
    ptrdiff_t   i,
                j;
    bool        timerange_given = false;
 
    main_argv = argv;
    progname = argv[0] ? argv[0] : "zic";
    if (TYPE_BIT(zic_t) < 64)
    {
        fprintf(stderr, "%s: %s\n", progname,
                _("wild compilation-time specification of zic_t"));
        return EXIT_FAILURE;
    }
    for (k = 1; k < argc; k++)
        if (strcmp(argv[k], "--version") == 0)
        {
            printf("zic %s\n", PG_VERSION);
            close_file(stdout, NULL, NULL, NULL);
            return EXIT_SUCCESS;
        }
        else if (strcmp(argv[k], "--help") == 0)
        {
            usage(stdout, EXIT_SUCCESS);
        }
    while ((c = getopt(argc, argv, "b:d:Dg:l:L:m:p:Pr:R:st:u:vy:")) != -1)
        switch (c)
        {
            default:
                usage(stderr, EXIT_FAILURE);
            case 'b':
                if (strcmp(optarg, "slim") == 0)
                {
                    if (0 < bloat)
                        error(_("incompatible -b options"));
                    bloat = -1;
                }
                else if (strcmp(optarg, "fat") == 0)
                {
                    if (bloat < 0)
                        error(_("incompatible -b options"));
                    bloat = 1;
                }
                else
                    error(_("invalid option: -b '%s'"), optarg);
                break;
            case 'd':
                if (directory)
                    duplicate_options("-d");
                directory = strdup(optarg);
                break;
            case 'D':
                skip_mkdir = true;
                break;
            case 'g':
 
                /*
                 * This undocumented option is present for compatibility with
                 * FreeBSD 14.
                 */
                group_option(optarg);
                break;
            case 'l':
                if (lcltime)
                    duplicate_options("-l");
                lcltime = strdup(optarg);
                break;
            case 'm':
                if (output_mode != no_mode)
                    duplicate_options("-m");
                output_mode = mode_option(optarg);
                break;
            case 'p':
                if (psxrules)
                    duplicate_options("-p");
                if (strcmp(optarg, "-") != 0)
                    warning(_("-p is obsolete"
                              " and likely ineffective"));
                psxrules = strdup(optarg);
                break;
            case 't':
                if (tzdefault)
                    duplicate_options("-t");
                tzdefault = strdup(optarg);
                break;
            case 'u':
                {
                    char       *colon = strchr(optarg, ':');
 
                    if (colon)
                        *colon = '\0';
                    owner_option(optarg);
                    if (colon)
                        group_option(colon + 1);
                }
                break;
            case 'y':
                warning(_("-y ignored"));
                break;
            case 'L':
                if (leapsec)
                    duplicate_options("-L");
                leapsec = strdup(optarg);
                break;
            case 'v':
                noise = true;
                break;
            case 'P':
                print_abbrevs = true;
                print_cutoff = time(NULL);
                break;
            case 'r':
                if (timerange_given)
                    duplicate_options("-r");
                if (!timerange_option(optarg))
                {
                    fprintf(stderr,
                            _("%s: invalid time range: %s\n"),
                            progname, optarg);
                    return EXIT_FAILURE;
                }
                timerange_given = true;
                break;
            case 'R':
                if (!redundant_time_option(optarg))
                {
                    fprintf(stderr, _("%s: invalid time: %s\n"),
                            progname, optarg);
                    return EXIT_FAILURE;
                }
                break;
            case 's':
                warning(_("-s ignored"));
                break;
        }
    if (optind == argc - 1 && strcmp(argv[optind], "=") == 0)
        usage(stderr, EXIT_FAILURE);    /* usage message by request */
    if (hi_time + (hi_time < ZIC_MAX) < redundant_time)
    {
        fprintf(stderr, _("%s: -R time exceeds -r cutoff\n"), progname);
        return EXIT_FAILURE;
    }
    if (redundant_time < lo_time)
        redundant_time = lo_time;
    if (bloat == 0)
    {
        static char const bloat_default[] = ZIC_BLOAT_DEFAULT;
 
        if (strcmp(bloat_default, "slim") == 0)
            bloat = -1;
        else if (strcmp(bloat_default, "fat") == 0)
            bloat = 1;
        else
            abort();            /* Configuration error.  */
    }
    if (directory == NULL)
        directory = "data";
    if (tzdefault == NULL)
        tzdefault = TZDEFAULT;
 
    if (optind < argc && leapsec != NULL)
    {
        infile(LEAPSEC_FILENUM, leapsec);
        adjleap();
    }
 
    for (k = optind; k < argc; k++)
        infile(k, argv[k]);
    if (errors)
        return EXIT_FAILURE;
    associate();
    use_safe_temp_permissions();
    change_directory(directory);
    directory_ends_in_slash = directory[strlen(directory) - 1] == '/';
    catch_signals();
    for (i = 0; i < nzones; i = j)
    {
        /*
         * Find the next non-continuation zone entry.
         */
        for (j = i + 1; j < nzones && zones[j].z_name == NULL; ++j)
            continue;
        outzone(&zones[i], j - i);
        check_for_signal();
    }
    make_links();
    if (lcltime != NULL)
    {
        eat(COMMAND_LINE_FILENUM, 1);
        dolink(lcltime, tzdefault, true);
    }
    if (psxrules != NULL)
    {
        eat(COMMAND_LINE_FILENUM, 1);
        dolink(psxrules, TZDEFRULES, true);
    }
    if (warnings && (ferror(stderr) || fclose(stderr) != 0))
        return EXIT_FAILURE;
    return errors ? EXIT_FAILURE : EXIT_SUCCESS;
}
 
static bool
componentcheck(char const *name, char const *component,
               char const *component_end)
{
    enum
    {
    component_len_max = 14};
    ptrdiff_t   component_len = component_end - component;
 
    if (component_len == 0)
    {
        if (!*name)
            error(_("empty file name"));
        else
            error(_(component == name
                    ? "file name '%s' begins with '/'"
                    : *component_end
                    ? "file name '%s' contains '//'"
                    : "file name '%s' ends with '/'"),
                  name);
        return false;
    }
    if (0 < component_len && component_len <= 2
        && component[0] == '.' && component_end[-1] == '.')
    {
        int         len = component_len;
 
        error(_("file name '%s' contains '%.*s' component"),
              name, len, component);
        return false;
    }
    if (noise)
    {
        if (0 < component_len && component[0] == '-')
            warning(_("file name '%s' component contains leading '-'"),
                    name);
        if (component_len_max < component_len)
            warning(_("file name '%s' contains overlength component"
                      " '%.*s...'"),
                    name, component_len_max, component);
    }
    return true;
}
 
static bool
namecheck(const char *name)
{
    char const *cp;
 
    /* Benign characters in a portable file name.  */
    static char const benign[] =
        "-/_"
        "abcdefghijklmnopqrstuvwxyz"
        "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
 
    /*
     * Non-control chars in the POSIX portable character set, excluding the
     * benign characters.
     */
    static char const printable_and_not_benign[] =
        " !\"#$%&'()*+,.0123456789:;<=>?@[\\]^`{|}~";
 
    char const *component = name;
 
    for (cp = name; *cp; cp++)
    {
        unsigned char c = *cp;
 
        if (noise && !strchr(benign, c))
        {
            warning((strchr(printable_and_not_benign, c)
                     ? _("file name '%s' contains byte '%c'")
                     : _("file name '%s' contains byte '\\%o'")),
                    name, c);
        }
        if (c == '/')
        {
            if (!componentcheck(name, component, cp))
                return false;
            component = cp + 1;
        }
    }
    return componentcheck(name, component, cp);
}
 
/* Return a random uint_fast64_t.  */
static uint_fast64_t
get_rand_u64(void)
{
#if HAVE_GETRANDOM
    static uint_fast64_t entropy_buffer[max(1, 256 / sizeof(uint_fast64_t))];
    static int  nwords;
 
    if (!nwords)
    {
        ssize_t     s;
 
        for (;; check_for_signal())
        {
            s = getrandom(entropy_buffer, sizeof entropy_buffer, 0);
            if (!(s < 0 && errno == EINTR))
                break;
        }
 
        nwords = s < 0 ? -1 : s / sizeof *entropy_buffer;
    }
    if (0 < nwords)
        return entropy_buffer[--nwords];
#endif
 
    /*
     * getrandom didn't work, so fall back on portable code that is not the
     * best because the seed isn't cryptographically random and 'rand' might
     * not be cryptographically secure.
     */
    {
        static bool initialized;
 
        if (!initialized)
        {
            srand(time(NULL));
            initialized = true;
        }
    }
 
    /*
     * Return a random number if rand() yields a random number and in the
     * typical case where RAND_MAX is one less than a power of two. In other
     * cases this code yields a sort-of-random number.
     */
    {
        uint_fast64_t rand_max = RAND_MAX,
                    nrand = rand_max < UINT_FAST64_MAX ? rand_max + 1 : 0,
                    rmod = INT_MAX < UINT_FAST64_MAX ? 0 : UINT_FAST64_MAX / nrand + 1,
                    r = 0,
                    rmax = 0;
 
        for (;; check_for_signal())
        {
            uint_fast64_t rmax1 = rmax;
 
            if (rmod)
            {
                /*
                 * Avoid signed integer overflow on theoretical platforms
                 * where uint_fast64_t promotes to int.
                 */
                rmax1 %= rmod;
                r %= rmod;
            }
            rmax1 = nrand * rmax1 + rand_max;
            r = nrand * r + rand();
            rmax = rmax < rmax1 ? rmax1 : UINT_FAST64_MAX;
            if (UINT_FAST64_MAX <= rmax)
                break;
        }
 
        return r;
    }
}
 
/*
 * Generate a randomish name in the same directory as *NAME.  If
 * *NAMEALLOC, put the name into *NAMEALLOC which is assumed to be
 * that returned by a previous call and is thus already almost set up
 * and equal to *NAME; otherwise, allocate a new name and put its
 * address into both *NAMEALLOC and *NAME.
 */
static void
random_dirent(char const **name, char **namealloc)
{
    char const *src = *name;
    char       *dst = *namealloc;
    static char const prefix[] = ".zic";
    static char const alphabet[] =
        "abcdefghijklmnopqrstuvwxyz"
        "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
        "0123456789";
    enum
    {
    prefixlen = sizeof prefix - 1, alphabetlen = sizeof alphabet - 1};
    int         suffixlen = 6;
    char const *lastslash = strrchr(src, '/');
    ptrdiff_t   dirlen = lastslash ? lastslash + 1 - src : 0;
    int         i;
    uint_fast64_t r;
    uint_fast64_t base = alphabetlen;
 
    /* BASE**6 */
    uint_fast64_t base__6 = base * base * base * base * base * base;
 
    /*
     * The largest uintmax_t that is a multiple of BASE**6.  Any random
     * uintmax_t value that is this value or greater, yields a biased
     * remainder when divided by BASE**6.  UNFAIR_MIN equals the mathematical
     * value of ((UINTMAX_MAX + 1) - (UINTMAX_MAX + 1) % BASE**6) computed
     * without overflow.
     */
    uint_fast64_t unfair_min = -((UINTMAX_MAX % base__6 + 1) % base__6);
 
    if (!dst)
    {
        char       *cp = dst = xmalloc(size_sum(dirlen, prefixlen + suffixlen + 1));
 
        memcpy(cp, src, dirlen);
        cp += dirlen;
        memcpy(cp, prefix, prefixlen);
        cp += prefixlen;
        cp[suffixlen] = '\0';
        *name = *namealloc = dst;
    }
 
    for (;; check_for_signal())
    {
        r = get_rand_u64();
        if (r < unfair_min)
            break;
    }
 
    for (i = 0; i < suffixlen; i++)
    {
        dst[dirlen + prefixlen + i] = alphabet[r % alphabetlen];
        r /= alphabetlen;
    }
}
 
/*
 * For diagnostics the directory, and file name relative to that
 * directory, respectively.  A diagnostic routine can name FILENAME by
 * outputting diagdir(FILENAME), then diagslash(FILENAME), then FILENAME.
 */
static char const *
diagdir(char const *filename)
{
    return *filename == '/' ? "" : directory;
}
static char const *
diagslash(char const *filename)
{
    return &"/"[*filename == '/' || directory_ends_in_slash];
}
 
/*
 * Prepare to write to the file *OUTNAME, using *TEMPNAME to store the
 * name of the temporary file that will eventually be renamed to
 * *OUTNAME.  Assign the temporary file's name to both *OUTNAME and
 * *TEMPNAME.  If *TEMPNAME is null, allocate the name of any such
 * temporary file; otherwise, reuse *TEMPNAME's storage, which is
 * already set up and only needs its trailing suffix updated.
 */
static FILE *
open_outfile(char const **outname, char **tempname)
{
    bool        dirs_made = false;
 
    if (!*tempname)
        random_dirent(outname, tempname);
 
    for (;; check_for_signal())
    {
        int         oflags = O_WRONLY | O_BINARY | O_CREAT | O_EXCL;
        int         fd = open(*outname, oflags, creat_perms);
        int         err;
 
        if (fd < 0)
            err = errno;
        else
        {
            FILE       *fp = fdopen(fd, "wb");
 
            if (fp)
                return fp;
            err = errno;
            close(fd);
        }
        if (err == ENOENT && !dirs_made)
        {
            mkdirs(*outname, true);
            dirs_made = true;
        }
        else if (err == EEXIST)
            random_dirent(outname, tempname);
        else
        {
            fprintf(stderr, _("%s: Can't create %s%s%s: %s\n"),
                    progname, diagdir(*outname), diagslash(*outname), *outname,
                    strerror(err));
            exit(EXIT_FAILURE);
        }
    }
}
 
/*
 * If TEMPNAME, the result is in the temporary file TEMPNAME even
 * though the user wanted it in NAME, so rename TEMPNAME to NAME.
 * Report an error and exit if there is trouble.  Also, free TEMPNAME.
 */
static void
rename_dest(char *tempname, char const *name)
{
    if (tempname)
    {
        if (rename(tempname, name) != 0)
        {
            int         rename_errno = errno;
 
            remove(tempname);
            fprintf(stderr, _("%s: rename to %s%s%s: %s\n"),
                    progname, diagdir(name), diagslash(name), name,
                    strerror(rename_errno));
            exit(EXIT_FAILURE);
        }
        free(tempname);
    }
}
 
/*
 * Create symlink contents suitable for symlinking TARGET to LINKNAME, as a
 * freshly allocated string.  TARGET should be a relative file name, and
 * is relative to the global variable DIRECTORY.  LINKNAME can be either
 * relative or absolute.  Return a null pointer if the symlink contents
 * was not computed because LINKNAME is absolute but DIRECTORY is not.
 */
#ifdef HAVE_SYMLINK
static char *
relname(char const *target, char const *linkname)
{
    size_t      i,
                taillen,
                dir_len = 0,
                dotdots = 0;
    ptrdiff_t   dotdotetcsize,
                linksize = INDEX_MAX;
    char const *f = target;
    char       *result = NULL;
 
    if (*linkname == '/')
    {
        /* Make F absolute too.  */
        size_t      len = strlen(directory);
        bool        needs_slash = len && directory[len - 1] != '/';
        size_t      lenslash = len + needs_slash;
        size_t      targetsize = strlen(target) + 1;
        char       *cp;
 
        if (*directory != '/')
            return NULL;
        linksize = size_sum(lenslash, targetsize);
        f = cp = result = xmalloc(linksize);
        memcpy(cp, directory, len);
        cp += len;
        *cp = '/';
        memcpy(cp + needs_slash, target, targetsize);
    }
    for (i = 0; f[i] && f[i] == linkname[i]; i++)
        if (f[i] == '/')
            dir_len = i + 1;
    for (; linkname[i]; i++)
        dotdots += linkname[i] == '/' && linkname[i - 1] != '/';
    taillen = strlen(f + dir_len);
    dotdotetcsize = size_sum(size_product(dotdots, 3), taillen + 1);
    if (dotdotetcsize <= linksize)
    {
        char       *cp;
 
        if (!result)
            result = xmalloc(dotdotetcsize);
        cp = result;
        for (i = 0; i < dotdots; i++)
        {
            memcpy(cp, "../", 3);
            cp += 3;
        }
        memmove(cp, f + dir_len, taillen + 1);
    }
    return result;
}
#endif                          /* HAVE_SYMLINK */
 
/*
 * Return true if A and B must have the same parent dir if A and B exist.
 * Return false if this is not necessarily true (though it might be true).
 * Keep it simple, and do not inspect the file system.
 */
ATTRIBUTE_PURE_114833
static bool
same_parent_dirs(char const *a, char const *b)
{
    for (; *a == *b; a++, b++)
        if (!*a)
            return true;
    return !(strchr(a, '/') || strchr(b, '/'));
}
 
static void
dolink(char const *target, char const *linkname, bool staysymlink)
{
    bool        linkdirs_made = false;
    int         link_errno;
    char       *tempname = NULL;
    char const *outname = linkname;
    int         targetissym = -2,
                linknameissym = -2;
 
    if (strcmp(target, "-") == 0)
    {
        if (remove(linkname) == 0 || errno == ENOENT || errno == ENOTDIR)
            return;
        else
        {
            char const *e = strerror(errno);
 
            fprintf(stderr, _("%s: Can't remove %s%s%s: %s\n"),
                    progname, diagdir(linkname), diagslash(linkname), linkname,
                    e);
            exit(EXIT_FAILURE);
        }
    }
 
    for (;; check_for_signal())
    {
        if (linkat(AT_FDCWD, target, AT_FDCWD, outname, AT_SYMLINK_FOLLOW)
            == 0)
        {
            link_errno = 0;
            break;
        }
        link_errno = errno;
        /* Linux 2.6.16 and 2.6.17 mishandle AT_SYMLINK_FOLLOW.  */
        if (link_errno == EINVAL)
            link_errno = ENOTSUP;
 
        /*
         * If linkat is not supported, fall back on link(A, B). However, skip
         * this if A is a relative symlink and A and B might not have the same
         * parent directory. On some platforms link(A, B) does not follow a
         * symlink A, and if A is relative it might misbehave elsewhere.
         */
        if (link_errno == ENOTSUP
            && (same_parent_dirs(target, outname)
                || 0 <= itssymlink(target, &targetissym)))
        {
            if (link(target, outname) == 0)
            {
                link_errno = 0;
                break;
            }
            link_errno = errno;
        }
        if (link_errno == EXDEV || link_errno == ENOTSUP)
            break;
 
        if (link_errno == EEXIST)
        {
            staysymlink &= !tempname;
            random_dirent(&outname, &tempname);
            if (staysymlink && itssymlink(linkname, &linknameissym))
                break;
        }
        else if (link_errno == ENOENT && !linkdirs_made)
        {
            mkdirs(linkname, true);
            linkdirs_made = true;
        }
        else
        {
            fprintf(stderr, _("%s: Can't link %s%s%s to %s%s%s: %s\n"),
                    progname, diagdir(target), diagslash(target), target,
                    diagdir(outname), diagslash(outname), outname,
                    strerror(link_errno));
            exit(EXIT_FAILURE);
        }
    }
    if (link_errno != 0)
    {
#ifdef HAVE_SYMLINK
        bool        absolute = *target == '/';
        char       *linkalloc = absolute ? NULL : relname(target, linkname);
        char const *contents = absolute ? target : linkalloc;
        int         symlink_errno = -1;
 
        if (contents)
        {
            for (;; check_for_signal())
            {
                if (symlink(contents, outname) == 0)
                {
                    symlink_errno = 0;
                    break;
                }
                symlink_errno = errno;
                if (symlink_errno == EEXIST)
                    random_dirent(&outname, &tempname);
                else if (symlink_errno == ENOENT && !linkdirs_made)
                {
                    mkdirs(linkname, true);
                    linkdirs_made = true;
                }
                else
                    break;
            }
        }
        free(linkalloc);
        if (symlink_errno == 0)
        {
            if (link_errno != ENOTSUP && link_errno != EEXIST)
                warning(_("symbolic link used because hard link failed: %s"),
                        strerror(link_errno));
        }
        else
#endif                          /* HAVE_SYMLINK */
        {
            FILE       *fp,
                       *tp;
            int         c;
 
            fp = fopen(target, "rb");
            if (!fp)
            {
                char const *e = strerror(errno);
 
                fprintf(stderr, _("%s: Can't read %s%s%s: %s\n"),
                        progname, diagdir(target), diagslash(target), target, e);
                exit(EXIT_FAILURE);
            }
            tp = open_outfile(&outname, &tempname);
            for (; (c = getc(fp)) != EOF; check_for_signal())
                putc(c, tp);
            close_file(tp, directory, linkname, tempname);
            close_file(fp, directory, target, NULL);
            if (link_errno != ENOTSUP)
                warning(_("copy used because hard link failed: %s"),
                        strerror(link_errno));
#ifdef HAVE_SYMLINK
            else if (symlink_errno < 0)
                warning(_("copy used because symbolic link not obvious"));
            else if (symlink_errno != ENOTSUP)
                warning(_("copy used because symbolic link failed: %s"),
                        strerror(symlink_errno));
#endif
        }
    }
    rename_dest(tempname, linkname);
}
 
/*
 * Return 1 if NAME is an absolute symbolic link, -1 if it is relative,
 * 0 if it is not a symbolic link.  If *CACHE is not -2, it is the
 * cached result of a previous call to this function with the same NAME.
 */
static int
itssymlink(char const *name, int *cache)
{
#ifdef HAVE_SYMLINK
    if (*cache == -2)
    {
        char        c = '\0';
 
        *cache = readlink(name, &c, 1) < 0 ? 0 : c == '/' ? 1 : -1;
    }
    return *cache;
#else
    return false;
#endif
}
 
/*
 * Associate sets of rules with zones.
 */
 
/*
 * Sort by rule name.
 */
 
static int
rcomp(const void *cp1, const void *cp2)
{
    struct rule const *r1 = cp1,
               *r2 = cp2;
 
    return strcmp(r1->r_name, r2->r_name);
}
 
static void
associate(void)
{
    struct zone *zp;
    struct rule *rp;
    ptrdiff_t   i,
                j,
                base,
                out;
 
    if (1 < nrules)
    {
        qsort(rules, nrules, sizeof *rules, rcomp);
        for (i = 0; i < nrules - 1; ++i)
        {
            if (strcmp(rules[i].r_name,
                       rules[i + 1].r_name) != 0)
                continue;
            if (rules[i].r_filenum == rules[i + 1].r_filenum)
                continue;
            eat(rules[i].r_filenum, rules[i].r_linenum);
            warning(_("same rule name in multiple files"));
            eat(rules[i + 1].r_filenum, rules[i + 1].r_linenum);
            warning(_("same rule name in multiple files"));
            for (j = i + 2; j < nrules; ++j)
            {
                if (strcmp(rules[i].r_name,
                           rules[j].r_name) != 0)
                    break;
                if (rules[i].r_filenum == rules[j].r_filenum)
                    continue;
                if (rules[i + 1].r_filenum
                    == rules[j].r_filenum)
                    continue;
                break;
            }
            i = j - 1;
        }
    }
    for (i = 0; i < nzones; ++i)
    {
        zp = &zones[i];
        zp->z_rules = NULL;
        zp->z_nrules = 0;
    }
    for (base = 0; base < nrules; base = out)
    {
        rp = &rules[base];
        for (out = base + 1; out < nrules; ++out)
            if (strcmp(rp->r_name, rules[out].r_name) != 0)
                break;
        for (i = 0; i < nzones; ++i)
        {
            zp = &zones[i];
            if (strcmp(zp->z_rule, rp->r_name) != 0)
                continue;
            zp->z_rules = rp;
            zp->z_nrules = out - base;
        }
    }
    for (i = 0; i < nzones; ++i)
    {
        zp = &zones[i];
        if (zp->z_nrules == 0)
        {
            /*
             * Maybe we have a local standard time offset.
             */
            eat(zp->z_filenum, zp->z_linenum);
            zp->z_save = getsave(zp->z_rule, &zp->z_isdst);
 
            /*
             * Note, though, that if there's no rule, a '%s' in the format is
             * a bad thing.
             */
            if (zp->z_format_specifier == 's')
                error("%s", _("%s in ruleless zone"));
        }
    }
    if (errors)
        exit(EXIT_FAILURE);
}
 
/*
 * Read a text line from FP into BUF, which is of size BUFSIZE.
 * Terminate it with a NUL byte instead of a newline.
 * Return true if successful, false if EOF.
 * On error, report the error and exit.
 */
static bool
inputline(FILE *fp, char *buf, ptrdiff_t bufsize)
{
    ptrdiff_t   linelen = 0,
                ch;
 
    for (; (ch = getc(fp)) != '\n'; check_for_signal())
    {
        if (ch < 0)
        {
            if (ferror(fp))
            {
                error(_("input error"));
                exit(EXIT_FAILURE);
            }
            if (linelen == 0)
                return false;
            error(_("unterminated line"));
            exit(EXIT_FAILURE);
        }
        if (!ch)
        {
            error(_("NUL input byte"));
            exit(EXIT_FAILURE);
        }
        buf[linelen++] = ch;
        if (linelen == bufsize)
        {
            error(_("line too long"));
            exit(EXIT_FAILURE);
        }
    }
    buf[linelen] = '\0';
    return true;
}
 
static void
infile(int fnum, char const *name)
{
    FILE       *fp;
    const struct lookup *lp;
    bool        wantcont;
    lineno_t    num;
 
    if (strcmp(name, "-") == 0)
    {
        fp = stdin;
    }
    else if ((fp = fopen(name, "r")) == NULL)
    {
        const char *e = strerror(errno);
 
        fprintf(stderr, _("%s: Cannot open %s: %s\n"),
                progname, name, e);
        exit(EXIT_FAILURE);
    }
    wantcont = false;
    for (num = 1;; ++num)
    {
        enum
        {
            bufsize_bound
        = (min(INT_MAX, INDEX_MAX) / FORMAT_LEN_GROWTH_BOUND)};
        char        buf[min(_POSIX2_LINE_MAX, bufsize_bound)];
        int         nfields;
        char       *fields[MAX_FIELDS];
 
        eat(fnum, num);
        if (!inputline(fp, buf, sizeof buf))
            break;
        nfields = getfields(buf, fields,
                            sizeof fields / sizeof *fields);
        if (nfields == 0)
        {
            /* nothing to do */
        }
        else if (wantcont)
        {
            wantcont = inzcont(fields, nfields);
        }
        else
        {
            struct lookup const *line_codes
            = fnum < 0 ? leap_line_codes : zi_line_codes;
 
            lp = byword(fields[0], line_codes);
            if (lp == NULL)
                error(_("input line of unknown type"));
            else
                switch (lp->l_value)
                {
                    case LC_RULE:
                        inrule(fields, nfields);
                        wantcont = false;
                        break;
                    case LC_ZONE:
                        wantcont = inzone(fields, nfields);
                        break;
                    case LC_LINK:
                        inlink(fields, nfields);
                        wantcont = false;
                        break;
                    case LC_LEAP:
                        inleap(fields, nfields);
                        wantcont = false;
                        break;
                    case LC_EXPIRES:
                        inexpires(fields, nfields);
                        wantcont = false;
                        break;
                    default:
                        unreachable();
                }
        }
        check_for_signal();
    }
    close_file(fp, NULL, filename(fnum), NULL);
    if (wantcont)
        error(_("expected continuation line not found"));
}
 
/*
 * Convert a string of one of the forms
 *  h   -h  hh:mm   -hh:mm  hh:mm:ss    -hh:mm:ss
 * into a number of seconds.
 * A null string maps to zero.
 * Call error with errstring and return zero on errors.
 */
 
static zic_t
gethms(char const *string, char const *errstring)
{
    zic_t       hh;
    int         sign,
                mm = 0,
                ss = 0;
    char        hhx,
                mmx,
                ssx,
                xr = '0',
                xs;
    int         tenths = 0;
    bool        ok = true;
 
    if (string == NULL || *string == '\0')
        return 0;
    if (*string == '-')
    {
        sign = -1;
        ++string;
    }
    else
        sign = 1;
    switch (sscanf(string,
                   "%" SCNdZIC "%c%d%c%d%c%1d%*[0]%c%*[0123456789]%c",
                   &hh, &hhx, &mm, &mmx, &ss, &ssx, &tenths, &xr, &xs))
    {
        default:
            ok = false;
            break;
        case 8:
            ok = is_digit(xr);
            ATTRIBUTE_FALLTHROUGH;
        case 7:
            ok &= ssx == '.';
            if (ok && noise)
                warning(_("fractional seconds rejected by"
                          " pre-2018 versions of zic"));
            ATTRIBUTE_FALLTHROUGH;
        case 5:
            ok &= mmx == ':';
            ATTRIBUTE_FALLTHROUGH;
        case 3:
            ok &= hhx == ':';
            ATTRIBUTE_FALLTHROUGH;
        case 1:
            break;
    }
    if (!ok)
    {
        error("%s", errstring);
        return 0;
    }
    if (hh < 0 ||
        mm < 0 || mm >= MINSPERHOUR ||
        ss < 0 || ss > SECSPERMIN)
    {
        error("%s", errstring);
        return 0;
    }
    ss += 5 + ((ss ^ 1) & (xr == '0')) <= tenths;   /* Round to even.  */
    if (noise && (hh > HOURSPERDAY ||
                  (hh == HOURSPERDAY && (mm != 0 || ss != 0))))
        warning(_("values over 24 hours not handled by pre-2007 versions of zic"));
    return oadd(omul(hh, sign * SECSPERHOUR),
                sign * (mm * SECSPERMIN + ss));
}
 
static zic_t
getsave(char *field, bool *isdst)
{
    int         dst = -1;
    zic_t       save;
    ptrdiff_t   fieldlen = strlen(field);
 
    if (fieldlen != 0)
    {
        char       *ep = field + fieldlen - 1;
 
        switch (*ep)
        {
            case 'd':
                dst = 1;
                *ep = '\0';
                break;
            case 's':
                dst = 0;
                *ep = '\0';
                break;
        }
    }
    save = gethms(field, _("invalid saved time"));
    *isdst = dst < 0 ? save != 0 : dst;
    return save;
}
 
static void
inrule(char **fields, int nfields)
{
    struct rule r;
 
    if (nfields != RULE_FIELDS)
    {
        error(_("wrong number of fields on Rule line"));
        return;
    }
    switch (*fields[RF_NAME])
    {
        case '\0':
        case ' ':
        case '\f':
        case '\n':
        case '\r':
        case '\t':
        case '\v':
        case '+':
        case '-':
        case '0':
        case '1':
        case '2':
        case '3':
        case '4':
        case '5':
        case '6':
        case '7':
        case '8':
        case '9':
            error(_("Invalid rule name \"%s\""), fields[RF_NAME]);
            return;
    }
    r.r_filenum = filenum;
    r.r_linenum = linenum;
    r.r_save = getsave(fields[RF_SAVE], &r.r_isdst);
    if (!rulesub(&r, fields[RF_LOYEAR], fields[RF_HIYEAR],
                 fields[RF_COMMAND], fields[RF_MONTH], fields[RF_DAY],
                 fields[RF_TOD]))
        return;
    r.r_name = xstrdup(fields[RF_NAME]);
    r.r_abbrvar = xstrdup(fields[RF_ABBRVAR]);
    if (max_abbrvar_len < strlen(r.r_abbrvar))
        max_abbrvar_len = strlen(r.r_abbrvar);
    rules = growalloc(rules, sizeof *rules, nrules, &nrules_alloc);
    rules[nrules++] = r;
}
 
static bool
inzone(char **fields, int nfields)
{
    ptrdiff_t   i;
 
    if (nfields < ZONE_MINFIELDS || nfields > ZONE_MAXFIELDS)
    {
        error(_("wrong number of fields on Zone line"));
        return false;
    }
    if (lcltime != NULL && strcmp(fields[ZF_NAME], tzdefault) == 0)
    {
        error(_("\"Zone %s\" line and -l option are mutually exclusive"),
              tzdefault);
        return false;
    }
    if (strcmp(fields[ZF_NAME], TZDEFRULES) == 0 && psxrules != NULL)
    {
        error(_("\"Zone %s\" line and -p option are mutually exclusive"),
              TZDEFRULES);
        return false;
    }
    for (i = 0; i < nzones; ++i)
        if (zones[i].z_name != NULL &&
            strcmp(zones[i].z_name, fields[ZF_NAME]) == 0)
        {
            error(_("duplicate zone name %s"
                    " (file \"%s\", line %" PRIdMAX ")"),
                  fields[ZF_NAME],
                  filename(zones[i].z_filenum),
                  zones[i].z_linenum);
            return false;
        }
    return inzsub(fields, nfields, false);
}
 
static bool
inzcont(char **fields, int nfields)
{
    if (nfields < ZONEC_MINFIELDS || nfields > ZONEC_MAXFIELDS)
    {
        error(_("wrong number of fields on Zone continuation line"));
        return false;
    }
    return inzsub(fields, nfields, true);
}
 
static bool
inzsub(char **fields, int nfields, bool iscont)
{
    char       *cp;
    char       *cp1;
    struct zone z;
    int         format_len;
    int         i_stdoff,
                i_rule,
                i_format;
    int         i_untilyear,
                i_untilmonth;
    int         i_untilday,
                i_untiltime;
    bool        hasuntil;
 
    if (iscont)
    {
        i_stdoff = ZFC_STDOFF;
        i_rule = ZFC_RULE;
        i_format = ZFC_FORMAT;
        i_untilyear = ZFC_TILYEAR;
        i_untilmonth = ZFC_TILMONTH;
        i_untilday = ZFC_TILDAY;
        i_untiltime = ZFC_TILTIME;
    }
    else if (!namecheck(fields[ZF_NAME]))
        return false;
    else
    {
        i_stdoff = ZF_STDOFF;
        i_rule = ZF_RULE;
        i_format = ZF_FORMAT;
        i_untilyear = ZF_TILYEAR;
        i_untilmonth = ZF_TILMONTH;
        i_untilday = ZF_TILDAY;
        i_untiltime = ZF_TILTIME;
    }
    z.z_filenum = filenum;
    z.z_linenum = linenum;
    z.z_stdoff = gethms(fields[i_stdoff], _("invalid UT offset"));
    cp = strchr(fields[i_format], '%');
    if (cp)
    {
        if ((*++cp != 's' && *cp != 'z') || strchr(cp, '%')
            || strchr(fields[i_format], '/'))
        {
            error(_("invalid abbreviation format"));
            return false;
        }
    }
    z.z_format_specifier = cp ? *cp : '\0';
    format_len = strlen(fields[i_format]);
    if (max_format_len < format_len)
        max_format_len = format_len;
    hasuntil = nfields > i_untilyear;
    if (hasuntil)
    {
        z.z_untilrule.r_filenum = filenum;
        z.z_untilrule.r_linenum = linenum;
        if (!rulesub(
                     &z.z_untilrule,
                     fields[i_untilyear],
                     "only",
                     "",
                     (nfields > i_untilmonth) ?
                     fields[i_untilmonth] : "Jan",
                     (nfields > i_untilday) ? fields[i_untilday] : "1",
                     (nfields > i_untiltime) ? fields[i_untiltime] : "0"))
            return false;
        z.z_untiltime = rpytime(&z.z_untilrule,
                                z.z_untilrule.r_loyear);
        if (iscont && nzones > 0 &&
            zones[nzones - 1].z_untiltime >= z.z_untiltime)
        {
            error(_("Zone continuation line end time is"
                    " not after end time of previous line"));
            return false;
        }
    }
    z.z_name = iscont ? NULL : xstrdup(fields[ZF_NAME]);
    z.z_rule = xstrdup(fields[i_rule]);
    z.z_format = cp1 = xstrdup(fields[i_format]);
    if (z.z_format_specifier == 'z')
    {
        cp1[cp - fields[i_format]] = 's';
        if (noise)
            warning(_("format '%s' not handled by pre-2015 versions of zic"),
                    fields[i_format]);
    }
    zones = growalloc(zones, sizeof *zones, nzones, &nzones_alloc);
    zones[nzones++] = z;
 
    /*
     * If there was an UNTIL field on this line, there's more information
     * about the zone on the next line.
     */
    return hasuntil;
}
 
static zic_t
getleapdatetime(char **fields, bool expire_line)
{
    const char *cp;
    const struct lookup *lp;
    zic_t       i,
                j;
    zic_t       year;
    int         month,
                day;
    zic_t       dayoff,
                tod;
    zic_t       t;
    char        xs;
 
    dayoff = 0;
    cp = fields[LP_YEAR];
    if (sscanf(cp, "%" SCNdZIC "%c", &year, &xs) != 1)
    {
        /*
         * Leapin' Lizards!
         */
        error(_("invalid leaping year"));
        return -1;
    }
    if (!expire_line)
    {
        if (!leapseen || leapmaxyear < year)
            leapmaxyear = year;
        if (!leapseen || leapminyear > year)
            leapminyear = year;
        leapseen = true;
    }
    j = EPOCH_YEAR;
    while (j != year)
    {
        if (year > j)
        {
            i = len_years[isleap(j)];
            ++j;
        }
        else
        {
            --j;
            i = -len_years[isleap(j)];
        }
        dayoff = oadd(dayoff, i);
    }
    if ((lp = byword(fields[LP_MONTH], mon_names)) == NULL)
    {
        error(_("invalid month name"));
        return -1;
    }
    month = lp->l_value;
    j = TM_JANUARY;
    while (j != month)
    {
        i = len_months[isleap(year)][j];
        dayoff = oadd(dayoff, i);
        ++j;
    }
    cp = fields[LP_DAY];
    if (sscanf(cp, "%d%c", &day, &xs) != 1 ||
        day <= 0 || day > len_months[isleap(year)][month])
    {
        error(_("invalid day of month"));
        return -1;
    }
    dayoff = oadd(dayoff, day - 1);
    t = omul(dayoff, SECSPERDAY);
    tod = gethms(fields[LP_TIME], _("invalid time of day"));
    t = tadd(t, tod);
    if (t < 0)
        error(_("leap second precedes Epoch"));
    return t;
}
 
static void
inleap(char **fields, int nfields)
{
    if (nfields != LEAP_FIELDS)
        error(_("wrong number of fields on Leap line"));
    else
    {
        zic_t       t = getleapdatetime(fields, false);
 
        if (0 <= t)
        {
            struct lookup const *lp = byword(fields[LP_ROLL], leap_types);
 
            if (!lp)
                error(_("invalid Rolling/Stationary field on Leap line"));
            else
            {
                int         correction = 0;
 
                if (!fields[LP_CORR][0])    /* infile() turns "-" into "".  */
                    correction = -1;
                else if (strcmp(fields[LP_CORR], "+") == 0)
                    correction = 1;
                else
                    error(_("invalid CORRECTION field on Leap line"));
                if (correction)
                    leapadd(t, correction, lp->l_value);
            }
        }
    }
}
 
static void
inexpires(char **fields, int nfields)
{
    if (nfields != EXPIRES_FIELDS)
        error(_("wrong number of fields on Expires line"));
    else if (0 <= leapexpires)
        error(_("multiple Expires lines"));
    else
        leapexpires = getleapdatetime(fields, true);
}
 
static void
inlink(char **fields, int nfields)
{
    struct link l;
 
    if (nfields != LINK_FIELDS)
    {
        error(_("wrong number of fields on Link line"));
        return;
    }
    if (*fields[LF_TARGET] == '\0')
    {
        error(_("blank TARGET field on Link line"));
        return;
    }
    if (!namecheck(fields[LF_LINKNAME]))
        return;
    l.l_filenum = filenum;
    l.l_linenum = linenum;
    l.l_target = xstrdup(fields[LF_TARGET]);
    l.l_linkname = xstrdup(fields[LF_LINKNAME]);
    links = growalloc(links, sizeof *links, nlinks, &nlinks_alloc);
    links[nlinks++] = l;
}
 
static bool
rulesub(struct rule *rp, const char *loyearp, const char *hiyearp,
        const char *typep, const char *monthp, const char *dayp,
        const char *timep)
{
    const struct lookup *lp;
    const char *cp;
    char       *dp;
    char       *ep;
    char        xs;
 
    if ((lp = byword(monthp, mon_names)) == NULL)
    {
        error(_("invalid month name"));
        return false;
    }
    rp->r_month = lp->l_value;
    rp->r_todisstd = false;
    rp->r_todisut = false;
    dp = xstrdup(timep);
    if (*dp != '\0')
    {
        ep = dp + strlen(dp) - 1;
        switch (lowerit(*ep))
        {
            case 's':           /* Standard */
                rp->r_todisstd = true;
                rp->r_todisut = false;
                *ep = '\0';
                break;
            case 'w':           /* Wall */
                rp->r_todisstd = false;
                rp->r_todisut = false;
                *ep = '\0';
                break;
            case 'g':           /* Greenwich */
            case 'u':           /* Universal */
            case 'z':           /* Zulu */
                rp->r_todisstd = true;
                rp->r_todisut = true;
                *ep = '\0';
                break;
        }
    }
    rp->r_tod = gethms(dp, _("invalid time of day"));
    free(dp);
 
    /*
     * Year work.
     */
    cp = loyearp;
    lp = byword(cp, begin_years);
    if (lp)
        switch (lp->l_value)
        {
            case YR_MINIMUM:
                warning(_("FROM year \"%s\" is obsolete;"
                          " treated as %d"),
                        cp, YEAR_32BIT_MIN - 1);
                rp->r_loyear = YEAR_32BIT_MIN - 1;
                break;
            default:
                unreachable();
        }
    else if (sscanf(cp, "%" SCNdZIC "%c", &rp->r_loyear, &xs) != 1)
    {
        error(_("invalid starting year"));
        return false;
    }
    cp = hiyearp;
    lp = byword(cp, end_years);
    rp->r_hiwasnum = lp == NULL;
    if (!rp->r_hiwasnum)
        switch (lp->l_value)
        {
            case YR_MAXIMUM:
                rp->r_hiyear = ZIC_MAX;
                break;
            case YR_ONLY:
                rp->r_hiyear = rp->r_loyear;
                break;
            default:
                unreachable();
        }
    else if (sscanf(cp, "%" SCNdZIC "%c", &rp->r_hiyear, &xs) != 1)
    {
        error(_("invalid ending year"));
        return false;
    }
    if (rp->r_loyear > rp->r_hiyear)
    {
        error(_("starting year greater than ending year"));
        return false;
    }
    if (*typep != '\0')
    {
        error(_("year type \"%s\" is unsupported; use \"-\" instead"),
              typep);
        return false;
    }
 
    /*
     * Day work. Accept things such as: 1 lastSunday last-Sunday
     * (undocumented; warn about this) Sun<=20 Sun>=7
     */
    dp = xstrdup(dayp);
    if ((lp = byword(dp, lasts)) != NULL)
    {
        rp->r_dycode = DC_DOWLEQ;
        rp->r_wday = lp->l_value;
        rp->r_dayofmonth = len_months[1][rp->r_month];
    }
    else
    {
        ep = strchr(dp, '<');
        if (ep)
            rp->r_dycode = DC_DOWLEQ;
        else
        {
            ep = strchr(dp, '>');
            if (ep)
                rp->r_dycode = DC_DOWGEQ;
            else
            {
                ep = dp;
                rp->r_dycode = DC_DOM;
            }
        }
        if (rp->r_dycode != DC_DOM)
        {
            *ep++ = 0;
            if (*ep++ != '=')
            {
                error(_("invalid day of month"));
                free(dp);
                return false;
            }
            if ((lp = byword(dp, wday_names)) == NULL)
            {
                error(_("invalid weekday name"));
                free(dp);
                return false;
            }
            rp->r_wday = lp->l_value;
        }
        if (sscanf(ep, "%d%c", &rp->r_dayofmonth, &xs) != 1 ||
            rp->r_dayofmonth <= 0 ||
            (rp->r_dayofmonth > len_months[1][rp->r_month]))
        {
            error(_("invalid day of month"));
            free(dp);
            return false;
        }
    }
    free(dp);
    return true;
}
 
static void
convert(uint_fast32_t val, char *buf)
{
    int         i;
    int         shift;
    unsigned char *const b = (unsigned char *) buf;
 
    for (i = 0, shift = 24; i < 4; ++i, shift -= 8)
        b[i] = (val >> shift) & 0xff;
}
 
static void
convert64(uint_fast64_t val, char *buf)
{
    int         i;
    int         shift;
    unsigned char *const b = (unsigned char *) buf;
 
    for (i = 0, shift = 56; i < 8; ++i, shift -= 8)
        b[i] = (val >> shift) & 0xff;
}
 
static void
puttzcode(zic_t val, FILE *fp)
{
    char        buf[4];
 
    convert(val, buf);
    fwrite(buf, sizeof buf, 1, fp);
}
 
static void
puttzcodepass(zic_t val, FILE *fp, int pass)
{
    if (pass == 1)
        puttzcode(val, fp);
    else
    {
        char        buf[8];
 
        convert64(val, buf);
        fwrite(buf, sizeof buf, 1, fp);
    }
}
 
static int
atcomp(const void *avp, const void *bvp)
{
    struct attype const *ap = avp,
               *bp = bvp;
    zic_t       a = ap->at,
                b = bp->at;
 
    return a < b ? -1 : a > b;
}
 
struct timerange
{
    int         defaulttype;
    ptrdiff_t   base,
                count;
    ptrdiff_t   leapbase,
                leapcount;
    bool        leapexpiry;
};
 
static struct timerange
limitrange(struct timerange r, zic_t lo, zic_t hi,
           zic_t const *ats, unsigned char const *types)
{
    /* Omit ordinary transitions < LO.  */
    while (0 < r.count && ats[r.base] < lo)
    {
        r.defaulttype = types[r.base];
        r.count--;
        r.base++;
    }
 
    /*
     * Omit as many initial leap seconds as possible, such that the first leap
     * second in the truncated list is <= LO, and is a positive leap second if
     * and only if it has a positive correction. This supports common TZif
     * readers that assume that the first leap second is positive if and only
     * if its correction is positive.
     */
    while (1 < r.leapcount && leap[r.leapbase + 1].trans <= lo)
    {
        r.leapcount--;
        r.leapbase++;
    }
    while (0 < r.leapbase
           && ((leap[r.leapbase - 1].corr < leap[r.leapbase].corr)
               != (0 < leap[r.leapbase].corr)))
    {
        r.leapcount++;
        r.leapbase--;
    }
 
 
    /* Omit ordinary and leap second transitions greater than HI + 1.  */
    if (hi < max_time)
    {
        while (0 < r.count && hi + 1 < ats[r.base + r.count - 1])
            r.count--;
        while (0 < r.leapcount && hi + 1 < leap[r.leapbase + r.leapcount - 1].trans)
            r.leapcount--;
    }
 
    /* Determine whether to append an expiration to the leap second table.  */
    r.leapexpiry = 0 <= leapexpires && leapexpires - 1 <= hi;
 
    return r;
}
 
static void
writezone(const char *const name, const char *const string, char version,
          int defaulttype)
{
    FILE       *fp;
    ptrdiff_t   i,
                j;
    int         pass;
    char       *tempname = NULL;
    char const *outname = name;
 
    /*
     * Allocate the ATS and TYPES arrays via a single malloc, as this is a bit
     * faster.  Do not malloc(0) if !timecnt, as that might return NULL even
     * on success.
     */
    zic_t      *ats = xmalloc(align_to(size_product(timecnt + !timecnt,
                                                    sizeof *ats + 1),
                                       alignof(zic_t)));
    void       *typesptr = ats + timecnt;
    unsigned char *types = typesptr;
    struct timerange rangeall = {0}, range32, range64;
 
    /*
     * Sort.
     */
    if (timecnt > 1)
        qsort(attypes, timecnt, sizeof *attypes, atcomp);
 
    /*
     * Optimize and skip unwanted transitions.
     */
    {
        ptrdiff_t   fromi,
                    toi;
 
        toi = 0;
        fromi = 0;
        for (; fromi < timecnt; ++fromi)
        {
            if (toi != 0)
            {
                /*
                 * Skip the previous transition if it is unwanted because its
                 * local time is not earlier. The UT offset additions can't
                 * overflow because of how the times were calculated.
                 */
                unsigned char type_2 =
                    toi == 1 ? 0 : attypes[toi - 2].type;
 
                if ((attypes[fromi].at
                     + utoffs[attypes[toi - 1].type])
                    <= attypes[toi - 1].at + utoffs[type_2])
                {
                    if (attypes[fromi].type == type_2)
                        toi--;
                    else
                        attypes[toi - 1].type =
                            attypes[fromi].type;
                    continue;
                }
            }
 
            /*
             * Use a transition if it is the first one, or if it cannot be
             * merged for other reasons, or if it transitions to different
             * timekeeping.
             */
            if (toi == 0
                || attypes[fromi].dontmerge
                || (utoffs[attypes[toi - 1].type]
                    != utoffs[attypes[fromi].type])
                || (isdsts[attypes[toi - 1].type]
                    != isdsts[attypes[fromi].type])
                || (desigidx[attypes[toi - 1].type]
                    != desigidx[attypes[fromi].type]))
                attypes[toi++] = attypes[fromi];
        }
        timecnt = toi;
    }
 
    if (noise)
    {
        if (1200 < timecnt)
        {
            if (TZ_MAX_TIMES < timecnt)
                warning(_("reference clients mishandle"
                          " more than %d transition times"),
                        TZ_MAX_TIMES);
            else
                warning(_("pre-2014 clients may mishandle"
                          " more than 1200 transition times"));
        }
        if (TZ_MAX_LEAPS < leapcnt)
            warning(_("reference clients mishandle more than %d leap seconds"),
                    TZ_MAX_LEAPS);
    }
 
    /*
     * Transfer.
     */
    for (i = 0; i < timecnt; ++i)
    {
        ats[i] = attypes[i].at;
        types[i] = attypes[i].type;
    }
 
    /*
     * Correct for leap seconds.
     */
    for (i = 0; i < timecnt; ++i)
    {
        j = leapcnt;
        while (--j >= 0)
            if (leap[j].trans - leap[j].corr < ats[i])
            {
                ats[i] = tadd(ats[i], leap[j].corr);
                break;
            }
    }
 
    rangeall.defaulttype = defaulttype;
    rangeall.count = timecnt;
    rangeall.leapcount = leapcnt;
    range64 = limitrange(rangeall, lo_time,
                         max(hi_time,
                             redundant_time - (ZIC_MIN < redundant_time)),
                         ats, types);
    range32 = limitrange(range64, ZIC32_MIN, ZIC32_MAX, ats, types);
 
    /*
     * TZif version 4 is needed if a no-op transition is appended to indicate
     * the expiration of the leap second table, or if the first leap second
     * transition is not to a +1 or -1 correction.
     */
    for (pass = 1; pass <= 2; pass++)
    {
        struct timerange const *r = pass == 1 ? &range32 : &range64;
 
        if (pass == 1 && !want_bloat())
            continue;
        if (r->leapexpiry)
        {
            if (noise)
                warning(_("%s: pre-2021b clients may mishandle"
                          " leap second expiry"),
                        name);
            version = '4';
        }
        if (0 < r->leapcount
            && leap[r->leapbase].corr != 1 && leap[r->leapbase].corr != -1)
        {
            if (noise)
                warning(_("%s: pre-2021b clients may mishandle"
                          " leap second table truncation"),
                        name);
            version = '4';
        }
        if (version == '4')
            break;
    }
 
    fp = open_outfile(&outname, &tempname);
 
    for (pass = 1; pass <= 2; ++pass)
    {
        ptrdiff_t   thistimei,
                    thistimecnt,
                    thistimelim;
        ptrdiff_t   thisleapi,
                    thisleapcnt,
                    thisleaplim;
        struct tzhead tzh;
        int         pretranstype = -1,
                    thisdefaulttype;
        bool        locut,
                    hicut,
                    thisleapexpiry;
        zic_t       lo,
                    thismin,
                    thismax;
        int         old0;
        char        omittype[TZ_MAX_TYPES];
        int         typemap[TZ_MAX_TYPES];
        int         thistypecnt,
                    stdcnt,
                    utcnt;
        char        thischars[TZ_MAX_CHARS];
        int         thischarcnt;
        bool        toomanytimes;
        int         indmap[TZ_MAX_CHARS];
 
        if (pass == 1)
        {
            thisdefaulttype = range32.defaulttype;
            thistimei = range32.base;
            thistimecnt = range32.count;
            toomanytimes = thistimecnt >> 31 >> 1 != 0;
            thisleapi = range32.leapbase;
            thisleapcnt = range32.leapcount;
            thisleapexpiry = range32.leapexpiry;
            thismin = ZIC32_MIN;
            thismax = ZIC32_MAX;
        }
        else
        {
            thisdefaulttype = range64.defaulttype;
            thistimei = range64.base;
            thistimecnt = range64.count;
            toomanytimes = thistimecnt >> 31 >> 31 >> 2 != 0;
            thisleapi = range64.leapbase;
            thisleapcnt = range64.leapcount;
            thisleapexpiry = range64.leapexpiry;
            thismin = min_time;
            thismax = max_time;
        }
        if (toomanytimes)
            error(_("too many transition times"));
 
        locut = thismin < lo_time && lo_time <= thismax;
        hicut = thismin <= hi_time && hi_time < thismax;
        thistimelim = thistimei + thistimecnt;
        memset(omittype, true, typecnt);
 
        /*
         * Determine whether to output a transition before the first
         * transition in range.  This is needed when the output is truncated
         * at the start, and is also useful when catering to buggy 32-bit
         * clients that do not use time type 0 for timestamps before the first
         * transition.
         */
        if ((locut || (pass == 1 && thistimei))
            && !(thistimecnt && ats[thistimei] == lo_time))
        {
            pretranstype = thisdefaulttype;
            omittype[pretranstype] = false;
        }
 
        /*
         * Arguably the default time type in the 32-bit data should be
         * range32.defaulttype, which is suited for timestamps just before
         * ZIC32_MIN.  However, zic traditionally used the time type of the
         * indefinite past instead.  Internet RFC 8532 says readers should
         * ignore 32-bit data, so this discrepancy matters only to obsolete
         * readers where the traditional type might be more appropriate even
         * if it's "wrong".  So, use the historical zic value, unless -r
         * specifies a low cutoff that excludes some 32-bit timestamps.
         */
        if (pass == 1 && lo_time <= thismin)
            thisdefaulttype = range64.defaulttype;
 
        if (locut)
            thisdefaulttype = unspecifiedtype;
        omittype[thisdefaulttype] = false;
        for (i = thistimei; i < thistimelim; i++)
            omittype[types[i]] = false;
        if (hicut)
            omittype[unspecifiedtype] = false;
 
        /*
         * Reorder types to make THISDEFAULTTYPE type 0. Use TYPEMAP to swap
         * OLD0 and THISDEFAULTTYPE so that THISDEFAULTTYPE appears as type 0
         * in the output instead of OLD0.  TYPEMAP also omits unused types.
         */
        old0 = strlen(omittype);
 
#ifndef LEAVE_SOME_PRE_2011_SYSTEMS_IN_THE_LURCH
 
        /*
         * For some pre-2011 systems: if the last-to-be-written standard (or
         * daylight) type has an offset different from the most recently used
         * offset, append an (unused) copy of the most recently used type (to
         * help get global "altzone" and "timezone" variables set correctly).
         */
        if (want_bloat())
        {
            int         mrudst,
                        mrustd,
                        hidst,
                        histd,
                        type;
 
            hidst = histd = mrudst = mrustd = -1;
            if (0 <= pretranstype)
            {
                if (isdsts[pretranstype])
                    mrudst = pretranstype;
                else
                    mrustd = pretranstype;
            }
            for (i = thistimei; i < thistimelim; i++)
                if (isdsts[types[i]])
                    mrudst = types[i];
                else
                    mrustd = types[i];
            for (i = old0; i < typecnt; i++)
            {
                int         h = (i == old0 ? thisdefaulttype
                                 : i == thisdefaulttype ? old0 : i);
 
                if (!omittype[h])
                {
                    if (isdsts[h])
                        hidst = i;
                    else
                        histd = i;
                }
            }
            if (hidst >= 0 && mrudst >= 0 && hidst != mrudst &&
                utoffs[hidst] != utoffs[mrudst])
            {
                isdsts[mrudst] = -1;
                type = addtype(utoffs[mrudst],
                               &chars[desigidx[mrudst]],
                               true,
                               ttisstds[mrudst],
                               ttisuts[mrudst]);
                isdsts[mrudst] = 1;
                omittype[type] = false;
            }
            if (histd >= 0 && mrustd >= 0 && histd != mrustd &&
                utoffs[histd] != utoffs[mrustd])
            {
                isdsts[mrustd] = -1;
                type = addtype(utoffs[mrustd],
                               &chars[desigidx[mrustd]],
                               false,
                               ttisstds[mrustd],
                               ttisuts[mrustd]);
                isdsts[mrustd] = 0;
                omittype[type] = false;
            }
        }
#endif                          /* !defined
                                 * LEAVE_SOME_PRE_2011_SYSTEMS_IN_THE_LURCH */
        thistypecnt = 0;
        for (i = old0; i < typecnt; i++)
            if (!omittype[i])
                typemap[i == old0 ? thisdefaulttype
                        : i == thisdefaulttype ? old0 : i]
                    = thistypecnt++;
 
        thischarcnt = stdcnt = utcnt = 0;
        for (i = old0; i < typecnt; i++)
        {
            if (omittype[i])
                continue;
            if (ttisstds[i])
                stdcnt = thistypecnt;
            if (ttisuts[i])
                utcnt = thistypecnt;
            addabbr(thischars, &thischarcnt, &chars[desigidx[i]]);
        }
 
        /*
         * Now that all abbrevs have been added to THISCHARS, it is safe to
         * set INDMAP without worrying about whether the abbrevs might move
         * later.
         */
        for (i = 0; i < TZ_MAX_CHARS; i++)
            indmap[i] = -1;
        for (i = old0; i < typecnt; i++)
            if (!omittype[i] && indmap[desigidx[i]] < 0)
                indmap[desigidx[i]] = addabbr(thischars, &thischarcnt,
                                              &chars[desigidx[i]]);
 
        if (pass == 1 && !want_bloat())
        {
            hicut = thisleapexpiry = false;
            pretranstype = -1;
            thistimecnt = thisleapcnt = 0;
            thistypecnt = thischarcnt = 1;
        }
#define DO(field)   fwrite(tzh.field, sizeof tzh.field, 1, fp)
        memset(&tzh, 0, sizeof tzh);
        memcpy(tzh.tzh_magic, TZ_MAGIC, sizeof tzh.tzh_magic);
        tzh.tzh_version[0] = version;
        convert(utcnt, tzh.tzh_ttisutcnt);
        convert(stdcnt, tzh.tzh_ttisstdcnt);
        convert(thisleapcnt + thisleapexpiry, tzh.tzh_leapcnt);
        convert((0 <= pretranstype) + thistimecnt + hicut,
                tzh.tzh_timecnt);
        convert(thistypecnt, tzh.tzh_typecnt);
        convert(thischarcnt, tzh.tzh_charcnt);
        DO(tzh_magic);
        DO(tzh_version);
        DO(tzh_reserved);
        DO(tzh_ttisutcnt);
        DO(tzh_ttisstdcnt);
        DO(tzh_leapcnt);
        DO(tzh_timecnt);
        DO(tzh_typecnt);
        DO(tzh_charcnt);
#undef DO
        if (pass == 1 && !want_bloat())
        {
            /* Output a minimal data block with just one time type.  */
            puttzcode(0, fp);   /* utoff */
            putc(0, fp);        /* dst */
            putc(0, fp);        /* index of abbreviation */
            putc(0, fp);        /* empty-string abbreviation */
            continue;
        }
 
        /* PG: print current timezone abbreviations if requested */
        if (print_abbrevs && pass == 2)
        {
            /* Print "type" data for periods ending after print_cutoff */
            for (i = thistimei; i < thistimelim; ++i)
            {
                if (i == thistimelim - 1 || ats[i + 1] > print_cutoff)
                {
                    unsigned char tm = types[i];
                    char       *thisabbrev = &thischars[indmap[desigidx[tm]]];
 
                    fprintf(stdout, "%s\t%" PRIdFAST64 "%s\n",
                            thisabbrev,
                            utoffs[tm],
                            isdsts[tm] ? "\tD" : "");
                }
            }
            /* Print the default type if we have no transitions at all */
            if (thistimei >= thistimelim)
            {
                unsigned char tm = defaulttype;
                char       *thisabbrev = &thischars[indmap[desigidx[tm]]];
 
                fprintf(stdout, "%s\t%" PRIdFAST64 "%s\n",
                        thisabbrev,
                        utoffs[tm],
                        isdsts[tm] ? "\tD" : "");
            }
        }
 
        if (pass == 2 && noise && 50 < thischarcnt)
            warning(_("%s: pre-2026 reference clients mishandle"
                      " more than 50 bytes of abbreviations"),
                    name);
 
        /*
         * Output a LO_TIME transition if needed; see limitrange. But do not
         * go below the minimum representable value for this pass.
         */
        lo = pass == 1 && lo_time < ZIC32_MIN ? ZIC32_MIN : lo_time;
 
        if (0 <= pretranstype)
            puttzcodepass(lo, fp, pass);
        for (i = thistimei; i < thistimelim; ++i)
        {
            puttzcodepass(ats[i], fp, pass);
        }
        if (hicut)
            puttzcodepass(hi_time + 1, fp, pass);
        if (0 <= pretranstype)
            putc(typemap[pretranstype], fp);
        for (i = thistimei; i < thistimelim; i++)
            putc(typemap[types[i]], fp);
        if (hicut)
            putc(typemap[unspecifiedtype], fp);
 
        for (i = old0; i < typecnt; i++)
        {
            int         h = (i == old0 ? thisdefaulttype
                             : i == thisdefaulttype ? old0 : i);
 
            if (!omittype[h])
            {
                puttzcode(utoffs[h], fp);
                putc(isdsts[h], fp);
                putc(indmap[desigidx[h]], fp);
            }
        }
        if (thischarcnt != 0)
            fwrite(thischars, sizeof thischars[0],
                   thischarcnt, fp);
        thisleaplim = thisleapi + thisleapcnt;
        for (i = thisleapi; i < thisleaplim; ++i)
        {
            zic_t       todo;
 
            if (leap[i].roll)
            {
                if (timecnt == 0 || leap[i].trans < ats[0])
                {
                    j = 0;
                    while (isdsts[j])
                        if (++j >= typecnt)
                        {
                            j = 0;
                            break;
                        }
                }
                else
                {
                    j = 1;
                    while (j < timecnt &&
                           ats[j] <= leap[i].trans)
                        ++j;
                    j = types[j - 1];
                }
                todo = tadd(leap[i].trans, -utoffs[j]);
            }
            else
                todo = leap[i].trans;
            puttzcodepass(todo, fp, pass);
            puttzcode(leap[i].corr, fp);
        }
        if (thisleapexpiry)
        {
            /*
             * Append a no-op leap correction indicating when the leap second
             * table expires.  Although this does not conform to Internet RFC
             * 9636, most clients seem to accept this and the plan is to amend
             * the RFC to allow this in version 4 TZif files.
             */
            puttzcodepass(leapexpires, fp, pass);
            puttzcode(thisleaplim ? leap[thisleaplim - 1].corr : 0, fp);
        }
        if (stdcnt != 0)
            for (i = old0; i < typecnt; i++)
                if (!omittype[i])
                    putc(ttisstds[i], fp);
        if (utcnt != 0)
            for (i = old0; i < typecnt; i++)
                if (!omittype[i])
                    putc(ttisuts[i], fp);
    }
    fprintf(fp, "\n%s\n", string);
    close_file(fp, directory, name, tempname);
    rename_dest(tempname, name);
    free(ats);
}
 
static char const *
abbroffset(char *buf, zic_t offset)
{
    char        sign = '+';
    int         seconds,
                minutes;
 
    if (offset < 0)
    {
        offset = -offset;
        sign = '-';
    }
 
    seconds = offset % SECSPERMIN;
    offset /= SECSPERMIN;
    minutes = offset % MINSPERHOUR;
    offset /= MINSPERHOUR;
    if (100 <= offset)
    {
        error(_("%%z UT offset magnitude exceeds 99:59:59"));
        return "%z";
    }
    else
    {
        char       *p = buf;
 
        *p++ = sign;
        *p++ = '0' + offset / 10;
        *p++ = '0' + offset % 10;
        if (minutes | seconds)
        {
            *p++ = '0' + minutes / 10;
            *p++ = '0' + minutes % 10;
            if (seconds)
            {
                *p++ = '0' + seconds / 10;
                *p++ = '0' + seconds % 10;
            }
        }
        *p = '\0';
        return buf;
    }
}
 
static char const disable_percent_s[] = "";
 
static ptrdiff_t
doabbr(char *abbr, struct zone const *zp, char const *letters,
       bool isdst, zic_t save, bool doquotes)
{
    char       *cp;
    ptrdiff_t   len;
    char const *format = zp->z_format;
    char const *slashp = strchr(format, '/');
 
    if (slashp == NULL)
    {
        char        letterbuf[PERCENT_Z_LEN_BOUND + 1];
 
        if (zp->z_format_specifier == 'z')
            letters = abbroffset(letterbuf, zp->z_stdoff + save);
        else if (!letters)
            letters = "%s";
        else if (letters == disable_percent_s)
            return 0;
        sprintf(abbr, format, letters);
    }
    else if (isdst)
        strcpy(abbr, slashp + 1);
    else
    {
        memcpy(abbr, format, slashp - format);
        abbr[slashp - format] = '\0';
    }
    len = strlen(abbr);
    if (!doquotes)
        return len;
    for (cp = abbr; is_alpha(*cp); cp++)
        continue;
    if (len > 0 && *cp == '\0')
        return len;
    abbr[len + 2] = '\0';
    abbr[len + 1] = '>';
    memmove(abbr + 1, abbr, len);
    abbr[0] = '<';
    return len + 2;
}
 
static void
updateminmax(const zic_t x)
{
    if (min_year > x)
        min_year = x;
    if (max_year < x)
        max_year = x;
}
 
static int
stringoffset(char *result, zic_t offset)
{
    int         hours;
    int         minutes;
    int         seconds;
    bool        negative = offset < 0;
    int         len = negative;
 
    if (negative)
    {
        offset = -offset;
        result[0] = '-';
    }
    seconds = offset % SECSPERMIN;
    offset /= SECSPERMIN;
    minutes = offset % MINSPERHOUR;
    offset /= MINSPERHOUR;
    if (offset >= HOURSPERDAY * DAYSPERWEEK)
    {
        result[0] = '\0';
        return 0;
    }
    hours = offset;
    len += sprintf(result + len, "%d", hours);
    if (minutes != 0 || seconds != 0)
    {
        len += sprintf(result + len, ":%02d", minutes);
        if (seconds != 0)
            len += sprintf(result + len, ":%02d", seconds);
    }
    return len;
}
 
static int
stringrule(char *result, struct rule *const rp, zic_t save, zic_t stdoff)
{
    zic_t       tod = rp->r_tod;
    int         compat = 0;
 
    if (rp->r_dycode == DC_DOM)
    {
        int         month,
                    total;
 
        if (rp->r_dayofmonth == 29 && rp->r_month == TM_FEBRUARY)
            return -1;
        total = 0;
        for (month = 0; month < rp->r_month; ++month)
            total += len_months[0][month];
        /* Omit the "J" in Jan and Feb, as that's shorter.  */
        if (rp->r_month <= 1)
            result += sprintf(result, "%d", total + rp->r_dayofmonth - 1);
        else
            result += sprintf(result, "J%d", total + rp->r_dayofmonth);
    }
    else
    {
        int         week;
        int         wday = rp->r_wday;
        int         wdayoff;
 
        if (rp->r_dycode == DC_DOWGEQ)
        {
            wdayoff = (rp->r_dayofmonth - 1) % DAYSPERWEEK;
            if (wdayoff)
                compat = 2013;
            wday -= wdayoff;
            tod += wdayoff * SECSPERDAY;
            week = 1 + (rp->r_dayofmonth - 1) / DAYSPERWEEK;
        }
        else if (rp->r_dycode == DC_DOWLEQ)
        {
            if (rp->r_dayofmonth == len_months[1][rp->r_month])
                week = 5;
            else
            {
                wdayoff = rp->r_dayofmonth % DAYSPERWEEK;
                if (wdayoff)
                    compat = 2013;
                wday -= wdayoff;
                tod += wdayoff * SECSPERDAY;
                week = rp->r_dayofmonth / DAYSPERWEEK;
            }
        }
        else
            return -1;          /* "cannot happen" */
        if (wday < 0)
            wday += DAYSPERWEEK;
        result += sprintf(result, "M%d.%d.%d",
                          rp->r_month + 1, week, wday);
    }
    if (rp->r_todisut)
        tod += stdoff;
    if (rp->r_todisstd && !rp->r_isdst)
        tod += save;
    if (tod != 2 * SECSPERMIN * MINSPERHOUR)
    {
        *result++ = '/';
        if (!stringoffset(result, tod))
            return -1;
        if (tod < 0)
        {
            if (compat < 2013)
                compat = 2013;
        }
        else if (SECSPERDAY <= tod)
        {
            if (compat < 1994)
                compat = 1994;
        }
    }
    return compat;
}
 
static int
rule_cmp(struct rule const *a, struct rule const *b)
{
    if (!a)
        return -!!b;
    if (!b)
        return 1;
    if (a->r_hiyear != b->r_hiyear)
        return a->r_hiyear < b->r_hiyear ? -1 : 1;
    if (a->r_hiyear == ZIC_MAX)
        return 0;
    if (a->r_month - b->r_month != 0)
        return a->r_month - b->r_month;
    return a->r_dayofmonth - b->r_dayofmonth;
}
 
/*
 * Store into RESULT a proleptic TZ string that represent the future
 * predictions for the zone ZPFIRST with ZONECOUNT entries.  Return a
 * compatibility indicator (a TZDB release year) if successful, a
 * negative integer if no such TZ string exists.
 */
static int
stringzone(char *result, struct zone const *zpfirst, ptrdiff_t zonecount)
{
    const struct zone *zp;
    struct rule *rp;
    struct rule *stdrp;
    struct rule *dstrp;
    ptrdiff_t   i;
    int         compat = 0;
    int         c;
    int         offsetlen;
    struct rule stdr,
                dstr;
    ptrdiff_t   len;
    int         dstcmp;
    struct rule *lastrp[2] = {NULL, NULL};
    struct zone zstr[2];
    struct zone const *stdzp;
    struct zone const *dstzp;
 
    result[0] = '\0';
 
    /*
     * Internet RFC 9636 section 6.1 says to use an empty TZ string if future
     * timestamps are truncated.
     */
    if (hi_time < max_time)
        return -1;
 
    zp = zpfirst + zonecount - 1;
    for (i = 0; i < zp->z_nrules; ++i)
    {
        struct rule **last;
        int         cmp;
 
        rp = &zp->z_rules[i];
        last = &lastrp[rp->r_isdst];
        cmp = rule_cmp(*last, rp);
        if (cmp < 0)
            *last = rp;
        else if (cmp == 0)
            return -1;
    }
    stdrp = lastrp[false];
    dstrp = lastrp[true];
    dstcmp = zp->z_nrules ? rule_cmp(dstrp, stdrp) : zp->z_isdst ? 1 : -1;
    stdzp = dstzp = zp;
 
    if (dstcmp < 0)
    {
        /* Standard time all year.  */
        dstrp = NULL;
    }
    else if (0 < dstcmp)
    {
        /*
         * DST all year.  Use an abbreviation like "XXX3EDT4,0/0,J365/23" for
         * EDT (-04) all year.
         */
        zic_t       save = dstrp ? dstrp->r_save : zp->z_save;
 
        if (0 <= save)
        {
            /*
             * Positive DST, the typical case for all-year DST. Fake a
             * timezone with negative DST.
             */
            stdzp = &zstr[0];
            dstzp = &zstr[1];
            zstr[0].z_stdoff = zp->z_stdoff + 2 * save;
            zstr[0].z_format = "XXX";   /* Any 3 letters will do.  */
            zstr[0].z_format_specifier = 0;
            zstr[1].z_stdoff = zstr[0].z_stdoff;
            zstr[1].z_format = zp->z_format;
            zstr[1].z_format_specifier = zp->z_format_specifier;
        }
        dstr.r_month = TM_JANUARY;
        dstr.r_dycode = DC_DOM;
        dstr.r_dayofmonth = 1;
        dstr.r_tod = 0;
        dstr.r_todisstd = dstr.r_todisut = false;
        dstr.r_isdst = true;
        dstr.r_save = save < 0 ? save : -save;
        dstr.r_abbrvar = dstrp ? dstrp->r_abbrvar : NULL;
        stdr.r_month = TM_DECEMBER;
        stdr.r_dycode = DC_DOM;
        stdr.r_dayofmonth = 31;
        stdr.r_tod = SECSPERDAY + dstr.r_save;
        stdr.r_todisstd = stdr.r_todisut = false;
        stdr.r_isdst = false;
        stdr.r_save = 0;
        stdr.r_abbrvar = save < 0 && stdrp ? stdrp->r_abbrvar : NULL;
        dstrp = &dstr;
        stdrp = &stdr;
    }
    len = doabbr(result, stdzp, stdrp ? stdrp->r_abbrvar : NULL,
                 false, 0, true);
    offsetlen = stringoffset(result + len, -stdzp->z_stdoff);
    if (!offsetlen)
    {
        result[0] = '\0';
        return -1;
    }
    len += offsetlen;
    if (dstrp == NULL)
        return compat;
    len += doabbr(result + len, dstzp, dstrp->r_abbrvar,
                  dstrp->r_isdst, dstrp->r_save, true);
    if (dstrp->r_save != SECSPERMIN * MINSPERHOUR)
    {
        offsetlen = stringoffset(result + len,
                                 -(dstzp->z_stdoff + dstrp->r_save));
        if (!offsetlen)
        {
            result[0] = '\0';
            return -1;
        }
        len += offsetlen;
    }
    result[len++] = ',';
    c = stringrule(result + len, dstrp, dstrp->r_save, stdzp->z_stdoff);
    if (c < 0)
    {
        result[0] = '\0';
        return -1;
    }
    if (compat < c)
        compat = c;
    len += strlen(result + len);
    result[len++] = ',';
    c = stringrule(result + len, stdrp, dstrp->r_save, stdzp->z_stdoff);
    if (c < 0)
    {
        result[0] = '\0';
        return -1;
    }
    if (compat < c)
        compat = c;
    return compat;
}
 
static void
outzone(const struct zone *zpfirst, ptrdiff_t zonecount)
{
    ptrdiff_t   i,
                j;
    zic_t       starttime,
                untiltime;
    bool        startttisstd;
    bool        startttisut;
    char       *startbuf;
    char       *ab;
    char       *envvar;
    int         max_abbr_len;
    int         max_envvar_len;
    int         compat;
    bool        do_extend;
    char        version;
    zic_t       nonTZlimtime = ZIC_MIN;
    int         nonTZlimtype = -1;
    zic_t       max_year0;
    int         defaulttype = -1;
    int         max_stringoffset_len = sizeof "-167:59:59" - 1;
    int         max_comma_stringrule_len = (sizeof ",M12.5.6/" - 1
                                            + max_stringoffset_len);
 
    check_for_signal();
 
    /* This cannot overflow; see FORMAT_LEN_GROWTH_BOUND.  */
    max_abbr_len = 2 + max_format_len + max_abbrvar_len;
    max_envvar_len = 2 * (max_abbr_len + max_stringoffset_len
                          + max_comma_stringrule_len);
 
    startbuf = xmalloc(max_abbr_len + 1);
    ab = xmalloc(max_abbr_len + 1);
    envvar = xmalloc(max_envvar_len + 1);
    INITIALIZE(untiltime);
    INITIALIZE(starttime);
 
    /*
     * Now. . .finally. . .generate some useful data!
     */
    timecnt = 0;
    typecnt = 0;
    charcnt = 0;
 
    /*
     * Thanks to Earl Chew for noting the need to unconditionally initialize
     * startttisstd.
     */
    startttisstd = false;
    startttisut = false;
    min_year = max_year = EPOCH_YEAR;
    if (leapseen)
    {
        updateminmax(leapminyear);
        updateminmax(leapmaxyear + (leapmaxyear < ZIC_MAX));
    }
    for (i = 0; i < zonecount; ++i)
    {
        struct zone const *zp = &zpfirst[i];
 
        if (i < zonecount - 1)
            updateminmax(zp->z_untilrule.r_loyear);
        for (j = 0; j < zp->z_nrules; ++j)
        {
            struct rule *rp = &zp->z_rules[j];
 
            updateminmax(rp->r_loyear);
            if (rp->r_hiwasnum)
                updateminmax(rp->r_hiyear);
        }
    }
 
    /*
     * Generate lots of data if a rule can't cover all future times.
     */
    compat = stringzone(envvar, zpfirst, zonecount);
    version = compat < 2013 ? '2' : '3';
    do_extend = compat < 0;
    if (noise)
    {
        if (!*envvar)
            warning("%s %s",
                    _("no proleptic TZ string for zone"),
                    zpfirst->z_name);
        else if (compat != 0)
        {
            /*
             * Circa-COMPAT clients, and earlier clients, might not work for
             * this zone when given dates before 1970 or after 2038.
             */
            warning(_("%s: pre-%d clients may mishandle"
                      " distant timestamps"),
                    zpfirst->z_name, compat);
        }
    }
    if (do_extend)
    {
        if (min_year >= ZIC_MIN + years_of_observations)
            min_year -= years_of_observations;
        else
            min_year = ZIC_MIN;
        if (max_year <= ZIC_MAX - years_of_observations)
            max_year += years_of_observations;
        else
            max_year = ZIC_MAX;
    }
    max_year = max(max_year, (redundant_time / (SECSPERDAY * DAYSPERNYEAR)
                              + EPOCH_YEAR + 1));
    max_year0 = max_year;
    if (want_bloat())
    {
        /*
         * For the benefit of older systems, generate data from 1900 through
         * 2038.
         */
        if (min_year > YEAR_32BIT_MIN - 1)
            min_year = YEAR_32BIT_MIN - 1;
        if (max_year < YEAR_32BIT_MAX)
            max_year = YEAR_32BIT_MAX;
    }
 
    if (min_time < lo_time || hi_time < max_time)
        unspecifiedtype = addtype(0, "-00", false, false, false);
 
    for (i = 0; i < zonecount; ++i)
    {
        /*
         * A guess that may well be corrected later.
         */
        zic_t       save = 0;
        struct zone const *zp = &zpfirst[i];
        bool        usestart = i > 0 && (zp - 1)->z_untiltime > min_time;
        bool        useuntil = i < (zonecount - 1);
        zic_t       stdoff = zp->z_stdoff;
        zic_t       startoff = stdoff;
 
        if (useuntil && zp->z_untiltime <= min_time)
            continue;
        eat(zp->z_filenum, zp->z_linenum);
        *startbuf = '\0';
        if (zp->z_nrules == 0)
        {
            int         type;
 
            save = zp->z_save;
            doabbr(startbuf, zp, NULL, zp->z_isdst, save, false);
            type = addtype(oadd(zp->z_stdoff, save),
                           startbuf, zp->z_isdst, startttisstd,
                           startttisut);
            if (usestart)
            {
                addtt(starttime, type);
                if (nonTZlimtime < starttime)
                {
                    nonTZlimtime = starttime;
                    nonTZlimtype = type;
                }
                usestart = false;
            }
            else
                defaulttype = type;
        }
        else
        {
            zic_t       year;
 
            for (year = min_year; year <= max_year; ++year)
            {
                if (useuntil && year > zp->z_untilrule.r_hiyear)
                    break;
 
                /*
                 * Mark which rules to do in the current year. For those to
                 * do, calculate rpytime(rp, year); The former TYPE field was
                 * also considered here.
                 */
                for (j = 0; j < zp->z_nrules; ++j)
                {
                    zic_t       one = 1;
                    zic_t       y2038_boundary = one << 31;
                    struct rule *rp = &zp->z_rules[j];
 
                    eats(zp->z_filenum, zp->z_linenum,
                         rp->r_filenum, rp->r_linenum);
                    rp->r_todo = year >= rp->r_loyear &&
                        year <= rp->r_hiyear;
                    if (rp->r_todo)
                    {
                        rp->r_temp = rpytime(rp, year);
                        rp->r_todo
                            = (rp->r_temp < y2038_boundary
                               || year <= max_year0);
                    }
                }
                for (;;)
                {
                    ptrdiff_t   k;
                    zic_t       jtime,
                                ktime;
                    zic_t       offset;
                    struct rule *rp;
                    int         type;
 
                    INITIALIZE(ktime);
                    if (useuntil)
                    {
                        /*
                         * Turn untiltime into UT assuming the current stdoff
                         * and save values.
                         */
                        untiltime = zp->z_untiltime;
                        if (!zp->z_untilrule.r_todisut)
                            untiltime = tadd(untiltime,
                                             -stdoff);
                        if (!zp->z_untilrule.r_todisstd)
                            untiltime = tadd(untiltime,
                                             -save);
                    }
 
                    /*
                     * Find the rule (of those to do, if any) that takes
                     * effect earliest in the year.
                     */
                    k = -1;
                    for (j = 0; j < zp->z_nrules; ++j)
                    {
                        struct rule *r = &zp->z_rules[j];
 
                        if (!r->r_todo)
                            continue;
                        eats(zp->z_filenum, zp->z_linenum,
                             r->r_filenum, r->r_linenum);
                        offset = r->r_todisut ? 0 : stdoff;
                        if (!r->r_todisstd)
                            offset = oadd(offset, save);
                        jtime = r->r_temp;
                        jtime = tadd(jtime, -offset);
                        if (k < 0 || jtime < ktime)
                        {
                            k = j;
                            ktime = jtime;
                        }
                        else if (jtime == ktime)
                        {
                            char const *dup_rules_msg =
                                _("two rules for same instant");
 
                            eats(zp->z_filenum, zp->z_linenum,
                                 r->r_filenum, r->r_linenum);
                            warning("%s", dup_rules_msg);
                            r = &zp->z_rules[k];
                            eats(zp->z_filenum, zp->z_linenum,
                                 r->r_filenum, r->r_linenum);
                            error("%s", dup_rules_msg);
                        }
                    }
                    if (k < 0)
                        break;  /* go on to next year */
                    rp = &zp->z_rules[k];
                    rp->r_todo = false;
                    if (useuntil && ktime >= untiltime)
                    {
                        if (!*startbuf
                            && (oadd(zp->z_stdoff, rp->r_save)
                                == startoff))
                            doabbr(startbuf, zp, rp->r_abbrvar,
                                   rp->r_isdst, rp->r_save,
                                   false);
                        break;
                    }
                    save = rp->r_save;
                    if (usestart && ktime == starttime)
                        usestart = false;
                    if (usestart)
                    {
                        if (ktime < starttime)
                        {
                            startoff = oadd(zp->z_stdoff,
                                            save);
                            doabbr(startbuf, zp,
                                   rp->r_abbrvar,
                                   rp->r_isdst,
                                   rp->r_save,
                                   false);
                            continue;
                        }
                        if (*startbuf == '\0'
                            && startoff == oadd(zp->z_stdoff,
                                                save))
                        {
                            doabbr(startbuf,
                                   zp,
                                   rp->r_abbrvar,
                                   rp->r_isdst,
                                   rp->r_save,
                                   false);
                        }
                    }
                    eats(zp->z_filenum, zp->z_linenum,
                         rp->r_filenum, rp->r_linenum);
                    doabbr(ab, zp, rp->r_abbrvar,
                           rp->r_isdst, rp->r_save, false);
                    offset = oadd(zp->z_stdoff, rp->r_save);
                    type = addtype(offset, ab, rp->r_isdst,
                                   rp->r_todisstd, rp->r_todisut);
                    if (defaulttype < 0 && !rp->r_isdst)
                        defaulttype = type;
                    addtt(ktime, type);
                    if (nonTZlimtime < ktime
                        && (useuntil || rp->r_hiyear != ZIC_MAX))
                    {
                        nonTZlimtime = ktime;
                        nonTZlimtype = type;
                    }
                }
            }
        }
        if (usestart)
        {
            bool        isdst = startoff != zp->z_stdoff;
 
            if (*startbuf == '\0' && zp->z_format)
                doabbr(startbuf, zp, disable_percent_s,
                       isdst, save, false);
            eat(zp->z_filenum, zp->z_linenum);
            if (*startbuf == '\0')
                error(_("cannot determine time zone abbreviation"
                        " to use just after until time"));
            else
            {
                int         type = addtype(startoff, startbuf, isdst,
                                           startttisstd, startttisut);
 
                if (defaulttype < 0 && !isdst)
                    defaulttype = type;
                addtt(starttime, type);
            }
        }
 
        /*
         * Now we may get to set starttime for the next zone line.
         */
        if (useuntil)
        {
            startttisstd = zp->z_untilrule.r_todisstd;
            startttisut = zp->z_untilrule.r_todisut;
            starttime = zp->z_untiltime;
            if (!startttisstd)
                starttime = tadd(starttime, -save);
            if (!startttisut)
                starttime = tadd(starttime, -stdoff);
        }
    }
    if (defaulttype < 0)
        defaulttype = 0;
    if (!do_extend && !want_bloat())
    {
        /* Keep trailing transitions that are no greater than this.  */
        zic_t       keep_at_max;
 
        /* The earliest transition into a time governed by the TZ string.  */
        zic_t       TZstarttime = ZIC_MAX;
 
        for (i = 0; i < timecnt; i++)
        {
            zic_t       at = attypes[i].at;
 
            if (nonTZlimtime < at && at < TZstarttime)
                TZstarttime = at;
        }
        if (TZstarttime == ZIC_MAX)
            TZstarttime = nonTZlimtime;
 
        /*
         * Omit trailing transitions deducible from the TZ string, and not
         * needed for -r or -R.
         */
        keep_at_max = max(TZstarttime, redundant_time);
        for (i = j = 0; i < timecnt; i++)
            if (attypes[i].at <= keep_at_max)
            {
                attypes[j].at = attypes[i].at;
                attypes[j].dontmerge = (attypes[i].at == TZstarttime
                                        && (nonTZlimtype != attypes[i].type
                                            || strchr(envvar, ',')));
                attypes[j].type = attypes[i].type;
                j++;
            }
        timecnt = j;
    }
    if (do_extend)
    {
        /*
         * If we're extending the explicitly listed observations for 400 years
         * because we can't fill the proleptic TZ field, check whether we
         * actually ended up explicitly listing observations through that
         * period.  If there aren't any near the end of the 400-year period,
         * add a redundant one at the end of the final year, to make it clear
         * that we are claiming to have definite knowledge of the lack of
         * transitions up to that point.
         */
        struct rule xr;
        struct attype *lastat;
 
        xr.r_month = TM_JANUARY;
        xr.r_dycode = DC_DOM;
        xr.r_dayofmonth = 1;
        xr.r_tod = 0;
        for (lastat = attypes, i = 1; i < timecnt; i++)
            if (attypes[i].at > lastat->at)
                lastat = &attypes[i];
        if (!lastat || lastat->at < rpytime(&xr, max_year - 1))
        {
            addtt(rpytime(&xr, max_year + 1),
                  lastat ? lastat->type : defaulttype);
            attypes[timecnt - 1].dontmerge = true;
        }
    }
    writezone(zpfirst->z_name, envvar, version, defaulttype);
    free(startbuf);
    free(ab);
    free(envvar);
}
 
static void
addtt(zic_t starttime, int type)
{
    attypes = growalloc(attypes, sizeof *attypes, timecnt, &timecnt_alloc);
    attypes[timecnt].at = starttime;
    attypes[timecnt].dontmerge = false;
    attypes[timecnt].type = type;
    ++timecnt;
}
 
static int
addtype(zic_t utoff, char const *abbr, bool isdst, bool ttisstd, bool ttisut)
{
    int         i,
                j;
    int         charcnt0;
 
    /* RFC 9636 section 3.2 specifies this range for utoff.  */
    if (!(-TWO_31_MINUS_1 <= utoff && utoff <= TWO_31_MINUS_1))
    {
        error(_("UT offset out of range"));
        exit(EXIT_FAILURE);
    }
    if (!want_bloat())
        ttisstd = ttisut = false;
 
    checkabbr(abbr);
 
    charcnt0 = charcnt;
    j = addabbr(chars, &charcnt, abbr);
    if (charcnt0 < charcnt)
    {
        /*
         * If an abbreviation was inserted, increment indexes no earlier than
         * the insert by the size of the insertion, so that they continue to
         * point to the same contents.
         */
        for (i = 0; i < typecnt; i++)
            if (j <= desigidx[i])
                desigidx[i] += charcnt - charcnt0;
    }
    else
    {
        /* If there's already an entry, return its index.  */
        for (i = 0; i < typecnt; i++)
            if (utoff == utoffs[i] && isdst == isdsts[i] && j == desigidx[i]
                && ttisstd == ttisstds[i] && ttisut == ttisuts[i])
                return i;
    }
 
    /*
     * There isn't one; add a new one, unless there are already too many.
     */
    if (typecnt >= TZ_MAX_TYPES)
    {
        error(_("too many local time types"));
        exit(EXIT_FAILURE);
    }
    i = typecnt++;
    utoffs[i] = utoff;
    isdsts[i] = isdst;
    ttisstds[i] = ttisstd;
    ttisuts[i] = ttisut;
    desigidx[i] = j;
    return i;
}
 
static void
leapadd(zic_t t, int correction, int rolling)
{
    ptrdiff_t   i;
 
    if (rolling && (lo_time != min_time || hi_time != max_time))
    {
        error(_("Rolling leap seconds not supported with -r"));
        exit(EXIT_FAILURE);
    }
    leap = growalloc(leap, sizeof *leap, leapcnt, &leap_alloc);
    for (i = 0; i < leapcnt; ++i)
        if (t <= leap[i].trans)
            break;
    memmove(&leap[i + 1], &leap[i], (leapcnt - i) * sizeof *leap);
    leap[i].trans = t;
    leap[i].corr = correction;
    leap[i].roll = rolling;
    ++leapcnt;
}
 
static void
adjleap(void)
{
    ptrdiff_t   i;
    zic_t       last = 0;
    zic_t       prevtrans = 0;
 
    /*
     * propagate leap seconds forward
     */
    for (i = 0; i < leapcnt; ++i)
    {
        if (leap[i].trans - prevtrans < 28 * SECSPERDAY)
        {
            error(_("Leap seconds too close together"));
            exit(EXIT_FAILURE);
        }
        prevtrans = leap[i].trans;
        leap[i].trans = tadd(prevtrans, last);
        last = leap[i].corr += last;
    }
 
    if (0 <= leapexpires)
    {
        leapexpires = oadd(leapexpires, last);
        if (!(leapcnt == 0 || (leap[leapcnt - 1].trans < leapexpires)))
        {
            error(_("last Leap time does not precede Expires time"));
            exit(EXIT_FAILURE);
        }
    }
}
 
/* Is A a space character in the C locale?  */
static bool
is_space(char a)
{
    switch (a)
    {
        default:
            return false;
        case ' ':
        case '\f':
        case '\n':
        case '\r':
        case '\t':
        case '\v':
            return true;
    }
}
 
/* Is A an alphabetic character in the C locale?  */
static bool
is_alpha(char a)
{
    switch (a)
    {
        default:
            return false;
        case 'A':
        case 'B':
        case 'C':
        case 'D':
        case 'E':
        case 'F':
        case 'G':
        case 'H':
        case 'I':
        case 'J':
        case 'K':
        case 'L':
        case 'M':
        case 'N':
        case 'O':
        case 'P':
        case 'Q':
        case 'R':
        case 'S':
        case 'T':
        case 'U':
        case 'V':
        case 'W':
        case 'X':
        case 'Y':
        case 'Z':
        case 'a':
        case 'b':
        case 'c':
        case 'd':
        case 'e':
        case 'f':
        case 'g':
        case 'h':
        case 'i':
        case 'j':
        case 'k':
        case 'l':
        case 'm':
        case 'n':
        case 'o':
        case 'p':
        case 'q':
        case 'r':
        case 's':
        case 't':
        case 'u':
        case 'v':
        case 'w':
        case 'x':
        case 'y':
        case 'z':
            return true;
    }
}
 
/*
 * If A is an uppercase character in the C locale, return its lowercase
 * counterpart.  Otherwise, return A.
 */
static char
lowerit(char a)
{
    switch (a)
    {
        default:
            return a;
        case 'A':
            return 'a';
        case 'B':
            return 'b';
        case 'C':
            return 'c';
        case 'D':
            return 'd';
        case 'E':
            return 'e';
        case 'F':
            return 'f';
        case 'G':
            return 'g';
        case 'H':
            return 'h';
        case 'I':
            return 'i';
        case 'J':
            return 'j';
        case 'K':
            return 'k';
        case 'L':
            return 'l';
        case 'M':
            return 'm';
        case 'N':
            return 'n';
        case 'O':
            return 'o';
        case 'P':
            return 'p';
        case 'Q':
            return 'q';
        case 'R':
            return 'r';
        case 'S':
            return 's';
        case 'T':
            return 't';
        case 'U':
            return 'u';
        case 'V':
            return 'v';
        case 'W':
            return 'w';
        case 'X':
            return 'x';
        case 'Y':
            return 'y';
        case 'Z':
            return 'z';
    }
}
 
/* case-insensitive equality */
ATTRIBUTE_PURE_114833
static bool
ciequal(const char *ap, const char *bp)
{
    while (lowerit(*ap) == lowerit(*bp++))
        if (*ap++ == '\0')
            return true;
    return false;
}
 
ATTRIBUTE_PURE_114833
static bool
itsabbr(const char *abbr, const char *word)
{
    if (lowerit(*abbr) != lowerit(*word))
        return false;
    ++word;
    while (*++abbr != '\0')
        do
        {
            if (*word == '\0')
                return false;
        } while (lowerit(*word++) != lowerit(*abbr));
    return true;
}
 
/* Return true if ABBR is an initial prefix of WORD, ignoring ASCII case.  */
 
ATTRIBUTE_PURE_114833
static bool
ciprefix(char const *abbr, char const *word)
{
    do
        if (!*abbr)
            return true;
    while (lowerit(*abbr++) == lowerit(*word++));
 
    return false;
}
 
static const struct lookup *
byword(const char *word, const struct lookup *table)
{
    const struct lookup *foundlp;
    const struct lookup *lp;
 
    if (word == NULL || table == NULL)
        return NULL;
 
    /*
     * If TABLE is LASTS and the word starts with "last" followed by a
     * non-'-', skip the "last" and look in WDAY_NAMES instead. Warn about any
     * usage of the undocumented prefix "last-".
     */
    if (table == lasts && ciprefix("last", word) && word[4])
    {
        if (word[4] == '-')
            warning(_("\"%s\" is undocumented; use \"last%s\" instead"),
                    word, word + 5);
        else
        {
            word += 4;
            table = wday_names;
        }
    }
 
    /*
     * Look for exact match.
     */
    for (lp = table; lp->l_word != NULL; ++lp)
        if (ciequal(word, lp->l_word))
            return lp;
 
    /*
     * Look for inexact match.
     */
    foundlp = NULL;
    for (lp = table; lp->l_word != NULL; ++lp)
        if (ciprefix(word, lp->l_word))
        {
            if (foundlp == NULL)
                foundlp = lp;
            else
                return NULL;    /* multiple inexact matches */
        }
 
    if (foundlp && noise)
    {
        /* Warn about any backward-compatibility issue with pre-2017c zic.  */
        bool        pre_2017c_match = false;
 
        for (lp = table; lp->l_word; lp++)
            if (itsabbr(word, lp->l_word))
            {
                if (pre_2017c_match)
                {
                    warning(_("\"%s\" is ambiguous in pre-2017c zic"), word);
                    break;
                }
                pre_2017c_match = true;
            }
    }
 
    return foundlp;
}
 
static int
getfields(char *cp, char **array, int arrayelts)
{
    char       *dp;
    int         nsubs;
 
    nsubs = 0;
    for (;;)
    {
        char       *dstart;
 
        while (is_space(*cp))
            ++cp;
        if (*cp == '\0' || *cp == '#')
            break;
        dstart = dp = cp;
        do
        {
            if ((*dp = *cp++) != '"')
                ++dp;
            else
                while ((*dp = *cp++) != '"')
                    if (*dp != '\0')
                        ++dp;
                    else
                    {
                        error(_("Odd number of quotation marks"));
                        exit(EXIT_FAILURE);
                    }
        } while (*cp && *cp != '#' && !is_space(*cp));
        if (is_space(*cp))
            ++cp;
        *dp = '\0';
        if (nsubs == arrayelts)
        {
            error(_("Too many input fields"));
            exit(EXIT_FAILURE);
        }
        array[nsubs++] = dstart + (*dstart == '-' && dp == dstart + 1);
    }
    return nsubs;
}
 
ATTRIBUTE_NORETURN static void
time_overflow(void)
{
    error(_("time overflow"));
    exit(EXIT_FAILURE);
}
 
/* Return T1 + T2, but diagnose any overflow and exit.  */
ATTRIBUTE_PURE_114833_HACK
static zic_t
oadd(zic_t t1, zic_t t2)
{
#ifdef ckd_add
    zic_t       sum;
 
    if (!ckd_add(&sum, t1, t2))
        return sum;
#else
    if (t1 < 0 ? ZIC_MIN - t1 <= t2 : t2 <= ZIC_MAX - t1)
        return t1 + t2;
#endif
    time_overflow();
}
 
/*
 * Return T1 + T2, but diagnose any overflow and exit.
 * This is like oadd, except the result must fit in min_time..max_time range,
 * which on oddball machines can be a smaller range than ZIC_MIN..ZIC_MAX.
 */
ATTRIBUTE_PURE_114833_HACK
static zic_t
tadd(zic_t t1, zic_t t2)
{
    zic_t       sum = oadd(t1, t2);
 
    if (min_time <= sum && sum <= max_time)
        return sum;
    time_overflow();
}
 
/* Return T1 * T2, but diagnose any overflow and exit.  */
ATTRIBUTE_PURE_114833_HACK
static zic_t
omul(zic_t t1, zic_t t2)
{
#ifdef ckd_mul
    zic_t       product;
 
    if (!ckd_mul(&product, t1, t2))
        return product;
#else
    if (t2 < 0
        ? ZIC_MAX / t2 <= t1 && (t2 == -1 || t1 <= ZIC_MIN / t2)
        : t2 == 0 || (ZIC_MIN / t2 <= t1 && t1 <= ZIC_MAX / t2))
        return t1 * t2;
#endif
    time_overflow();
}
 
/*
 * Given a rule, and a year, compute the date (in seconds since January 1,
 * 1970, 00:00 LOCAL time) in that year that the rule refers to.
 * Do not count leap seconds.  On error, diagnose and exit.
 */
 
static zic_t
rpytime(const struct rule *rp, zic_t wantedy)
{
    int         m,
                i;
    zic_t       dayoff;         /* with a nod to Margaret O. */
    zic_t       t,
                y;
    int         yrem;
 
    m = TM_JANUARY;
    y = EPOCH_YEAR;
 
    /*
     * dayoff = floor((wantedy - y) / YEARSPERREPEAT) * DAYSPERREPEAT, sans
     * overflow.
     */
    yrem = wantedy % YEARSPERREPEAT - y % YEARSPERREPEAT;
    dayoff = ((wantedy / YEARSPERREPEAT - y / YEARSPERREPEAT
               + yrem / YEARSPERREPEAT - (yrem % YEARSPERREPEAT < 0))
              * DAYSPERREPEAT);
    /* wantedy = y + ((wantedy - y) mod YEARSPERREPEAT), sans overflow.  */
    wantedy = y + (yrem + 2 * YEARSPERREPEAT) % YEARSPERREPEAT;
 
    while (wantedy != y)
    {
        i = len_years[isleap(y)];
        dayoff = oadd(dayoff, i);
        y++;
    }
    while (m != rp->r_month)
    {
        i = len_months[isleap(y)][m];
        dayoff = oadd(dayoff, i);
        ++m;
    }
    i = rp->r_dayofmonth;
    if (m == TM_FEBRUARY && i == 29 && !isleap(y))
    {
        if (rp->r_dycode == DC_DOWLEQ)
            --i;
        else
        {
            error(_("use of 2/29 in non leap-year"));
            exit(EXIT_FAILURE);
        }
    }
    --i;
    dayoff = oadd(dayoff, i);
    if (rp->r_dycode == DC_DOWGEQ || rp->r_dycode == DC_DOWLEQ)
    {
        /*
         * Don't trust mod of negative numbers.
         */
        zic_t       wday = ((EPOCH_WDAY + dayoff % DAYSPERWEEK + DAYSPERWEEK)
                            % DAYSPERWEEK);
 
        while (wday != rp->r_wday)
            if (rp->r_dycode == DC_DOWGEQ)
            {
                dayoff = oadd(dayoff, 1);
                if (++wday >= DAYSPERWEEK)
                    wday = 0;
                ++i;
            }
            else
            {
                dayoff = oadd(dayoff, -1);
                if (--wday < 0)
                    wday = DAYSPERWEEK - 1;
                --i;
            }
        if (i < 0 || i >= len_months[isleap(y)][m])
        {
            if (noise)
                warning(_("rule goes past start/end of month; \
will not work with pre-2004 versions of zic"));
        }
    }
    t = omul(dayoff, SECSPERDAY);
    return tadd(t, rp->r_tod);
}
 
static void
checkabbr(char const *string)
{
    if (strcmp(string, GRANDPARENTED) != 0)
    {
        const char *cp;
        const char *mp;
 
        cp = string;
        mp = NULL;
        while (is_alpha(*cp) || is_digit(*cp)
               || *cp == '-' || *cp == '+')
            ++cp;
        if (noise && cp - string < 3)
            mp = _("time zone abbreviation has fewer than 3 characters");
        if (cp - string > ZIC_MAX_ABBR_LEN_WO_WARN)
            mp = _("time zone abbreviation has too many characters");
        if (*cp != '\0')
            mp = _("time zone abbreviation differs from POSIX standard");
        if (mp != NULL)
            warning("%s (%s)", mp, string);
    }
}
 
/*
 * Put into CHS, which currently contains *PNCHS bytes containing
 * NUL-terminated abbreviations none of which are suffixes of another,
 * the abbreviation ABBR including its trailing NUL.
 * If ABBR does not already appear in CHS,
 * possibly as a suffix of an existing abbreviation,
 * add ABBR to CHS, remove from CHS any abbreviation
 * that is a suffix of ABBR, and increment *PNCHS accordingly.
 * Return the index of ABBR after any modifications to CHS are made.
 *
 * If all abbreviations have already been added, this function
 * lets the caller look up the index of an existing abbreviation.
 */
static int
addabbr(char chs[TZ_MAX_CHARS], int *pnchs, char const *abbr)
{
    int         nchs = *pnchs;
    int         alen = strlen(abbr),
                nchs_incr = alen + 1;
    int         i;
 
    for (i = 0; i < nchs;)
    {
        int         clen = strlen(&chs[i]);
 
        if (alen <= clen)
        {
            /*
             * If ABBR is a suffix of an abbreviation in CHS, return the index
             * of ABBR in CHS.
             */
            int         isuff = i + (clen - alen);
 
            if (memcmp(&chs[isuff], abbr, alen) == 0)
                return isuff;
        }
        else if (memcmp(&chs[i], &abbr[alen - clen], clen) == 0)
        {
            /*
             * An abbreviation in CHS is a substring of ABBR. Replace it with
             * ABBR, instead of the more-common actions of appending ABBR or
             * doing nothing.
             */
            nchs_incr = alen - clen;
            break;
        }
        i += clen + 1;
    }
    if (TZ_MAX_CHARS < nchs + nchs_incr)
    {
        error(_("too many, or too long, time zone abbreviations"));
        exit(EXIT_FAILURE);
    }
    memmove(&chs[i + nchs_incr], &chs[i], nchs - i);
    memcpy(&chs[i], abbr, nchs_incr);
    *pnchs = nchs + nchs_incr;
    return i;
}
 
/*
 * Ensure that the directories of ARGNAME exist, by making any missing
 * ones.  If ANCESTORS, do this only for ARGNAME's ancestors; otherwise,
 * do it for ARGNAME too.  Exit with failure if there is trouble.
 * Do not consider an existing file to be trouble.
 */
static void
mkdirs(char const *argname, bool ancestors)
{
    /*
     * If -D was specified, do not create directories. If a file operation's
     * parent directory is missing, the operation will fail and be diagnosed.
     */
    if (!skip_mkdir)
    {
 
        char       *name = xstrdup(argname);
        char       *cp = name;
 
        /*
         * On MS-Windows systems, do not worry about drive letters or
         * backslashes, as this should suffice in practice.  Time zone names
         * do not use drive letters and backslashes.  If the -d option of zic
         * does not name an already-existing directory, it can use slashes to
         * separate the already-existing ancestor prefix from the
         * to-be-created subdirectories.
         */
 
        /* Do not mkdir a root directory, as it must exist.  */
        while (*cp == '/')
            cp++;
 
        while (cp && ((cp = strchr(cp, '/')) || !ancestors))
        {
            if (cp)
                *cp = '\0';
 
            /*
             * Try to create it.  It's OK if creation fails because the
             * directory already exists, perhaps because some other process
             * just created it.  For simplicity do not check first whether it
             * already exists, as that is checked anyway if the mkdir fails.
             */
            if (mkdir(name, MKDIR_PERMS) < 0)
            {
                /*
                 * Do not report an error if err == EEXIST, because some other
                 * process might have made the directory in the meantime.
                 * Likewise for ENOSYS, because Solaris 10 mkdir fails with
                 * ENOSYS if the directory is an automounted mount point.
                 * Likewise for EACCES, since mkdir can fail with EACCES
                 * merely because the parent directory is unwritable. Likewise
                 * for most other error numbers.
                 */
                int         err = errno;
 
                if (err == ELOOP || err == ENAMETOOLONG
                    || err == ENOENT || err == ENOTDIR)
                {
                    error(_("%s: Cannot create directory %s: %s"),
                          progname, name, strerror(err));
                    exit(EXIT_FAILURE);
                }
            }
            if (cp)
                *cp++ = '/';
        }
        free(name);
    }
}