hba.c

Go to the documentation of this file.

/*-------------------------------------------------------------------------
 *
 * hba.c
 *    Routines to handle host based authentication (that's the scheme
 *    wherein you authenticate a user by seeing what IP address the system
 *    says he comes from and choosing authentication method based on it).
 *
 * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *    src/backend/libpq/hba.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"
 
#include <ctype.h>
#include <pwd.h>
#include <fcntl.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <netdb.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
 
#include "catalog/pg_collation.h"
#include "common/ip.h"
#include "common/string.h"
#include "libpq/hba.h"
#include "libpq/ifaddr.h"
#include "libpq/libpq-be.h"
#include "libpq/oauth.h"
#include "postmaster/postmaster.h"
#include "regex/regex.h"
#include "replication/walsender.h"
#include "storage/fd.h"
#include "utils/acl.h"
#include "utils/conffiles.h"
#include "utils/guc.h"
#include "utils/memutils.h"
#include "utils/varlena.h"
 
#ifdef USE_LDAP
#ifdef WIN32
#include <winldap.h>
#else
#include <ldap.h>
#endif
#endif
 
 
/* callback data for check_network_callback */
typedef struct check_network_data
{
    IPCompareMethod method;     /* test method */
    SockAddr   *raddr;          /* client's actual address */
    bool        result;         /* set to true if match */
} check_network_data;
 
typedef struct
{
    const char *filename;
    int         linenum;
} tokenize_error_callback_arg;
 
#define token_has_regexp(t) (t->regex != NULL)
#define token_is_member_check(t)    (!t->quoted && t->string[0] == '+')
#define token_is_keyword(t, k)  (!t->quoted && strcmp(t->string, k) == 0)
#define token_matches(t, k)  (strcmp(t->string, k) == 0)
#define token_matches_insensitive(t,k) (pg_strcasecmp(t->string, k) == 0)
 
/*
 * Memory context holding the list of TokenizedAuthLines when parsing
 * HBA or ident configuration files.  This is created when opening the first
 * file (depth of CONF_FILE_START_DEPTH).
 */
static MemoryContext tokenize_context = NULL;
 
/*
 * pre-parsed content of HBA config file: list of HbaLine structs.
 * parsed_hba_context is the memory context where it lives.
 */
static List *parsed_hba_lines = NIL;
static MemoryContext parsed_hba_context = NULL;
 
/*
 * pre-parsed content of ident mapping file: list of IdentLine structs.
 * parsed_ident_context is the memory context where it lives.
 */
static List *parsed_ident_lines = NIL;
static MemoryContext parsed_ident_context = NULL;
 
/*
 * The following character array represents the names of the authentication
 * methods that are supported by PostgreSQL.
 *
 * Note: keep this in sync with the UserAuth enum in hba.h.
 */
static const char *const UserAuthName[] =
{
    "reject",
    "implicit reject",          /* Not a user-visible option */
    "trust",
    "ident",
    "password",
    "md5",
    "scram-sha-256",
    "gss",
    "sspi",
    "pam",
    "bsd",
    "ldap",
    "cert",
    "radius",
    "peer",
    "oauth",
};
 
/*
 * Make sure UserAuthName[] tracks additions to the UserAuth enum
 */
StaticAssertDecl(lengthof(UserAuthName) == USER_AUTH_LAST + 1,
                 "UserAuthName[] must match the UserAuth enum");
 
 
static List *tokenize_expand_file(List *tokens, const char *outer_filename,
                                  const char *inc_filename, int elevel,
                                  int depth, char **err_msg);
static bool parse_hba_auth_opt(char *name, char *val, HbaLine *hbaline,
                               int elevel, char **err_msg);
static int  regcomp_auth_token(AuthToken *token, char *filename, int line_num,
                               char **err_msg, int elevel);
static int  regexec_auth_token(const char *match, AuthToken *token,
                               size_t nmatch, regmatch_t pmatch[]);
static void tokenize_error_callback(void *arg);
 
 
static bool
pg_isblank(const char c)
{
    /* don't accept non-ASCII data */
    return (!IS_HIGHBIT_SET(c) && isblank(c));
}
 
 
/*
 * Grab one token out of the string pointed to by *lineptr.
 *
 * Tokens are strings of non-blank characters bounded by blank characters,
 * commas, beginning of line, and end of line.  Blank means space or tab.
 *
 * Tokens can be delimited by double quotes (this allows the inclusion of
 * commas, blanks, and '#', but not newlines).  As in SQL, write two
 * double-quotes to represent a double quote.
 *
 * Comments (started by an unquoted '#') are skipped, i.e. the remainder
 * of the line is ignored.
 *
 * (Note that line continuation processing happens before tokenization.
 * Thus, if a continuation occurs within quoted text or a comment, the
 * quoted text or comment is considered to continue to the next line.)
 *
 * The token, if any, is returned into buf (replacing any previous
 * contents), and *lineptr is advanced past the token.
 *
 * Also, we set *initial_quote to indicate whether there was quoting before
 * the first character.  (We use that to prevent "@x" from being treated
 * as a file inclusion request.  Note that @"x" should be so treated;
 * we want to allow that to support embedded spaces in file paths.)
 *
 * We set *terminating_comma to indicate whether the token is terminated by a
 * comma (which is not returned, nor advanced over).
 *
 * The only possible error condition is lack of terminating quote, but we
 * currently do not detect that, but just return the rest of the line.
 *
 * If successful: store dequoted token in buf and return true.
 * If no more tokens on line: set buf to empty and return false.
 */
static bool
next_token(char **lineptr, StringInfo buf,
           bool *initial_quote, bool *terminating_comma)
{
    int         c;
    bool        in_quote = false;
    bool        was_quote = false;
    bool        saw_quote = false;
 
    /* Initialize output parameters */
    resetStringInfo(buf);
    *initial_quote = false;
    *terminating_comma = false;
 
    /* Move over any whitespace and commas preceding the next token */
    while ((c = (*(*lineptr)++)) != '\0' && (pg_isblank(c) || c == ','))
        ;
 
    /*
     * Build a token in buf of next characters up to EOL, unquoted comma, or
     * unquoted whitespace.
     */
    while (c != '\0' &&
           (!pg_isblank(c) || in_quote))
    {
        /* skip comments to EOL */
        if (c == '#' && !in_quote)
        {
            while ((c = (*(*lineptr)++)) != '\0')
                ;
            break;
        }
 
        /* we do not pass back a terminating comma in the token */
        if (c == ',' && !in_quote)
        {
            *terminating_comma = true;
            break;
        }
 
        if (c != '"' || was_quote)
            appendStringInfoChar(buf, c);
 
        /* Literal double-quote is two double-quotes */
        if (in_quote && c == '"')
            was_quote = !was_quote;
        else
            was_quote = false;
 
        if (c == '"')
        {
            in_quote = !in_quote;
            saw_quote = true;
            if (buf->len == 0)
                *initial_quote = true;
        }
 
        c = *(*lineptr)++;
    }
 
    /*
     * Un-eat the char right after the token (critical in case it is '\0',
     * else next call will read past end of string).
     */
    (*lineptr)--;
 
    return (saw_quote || buf->len > 0);
}
 
/*
 * Construct a palloc'd AuthToken struct, copying the given string.
 */
static AuthToken *
make_auth_token(const char *token, bool quoted)
{
    AuthToken  *authtoken;
    int         toklen;
 
    toklen = strlen(token);
    /* we copy string into same palloc block as the struct */
    authtoken = (AuthToken *) palloc0(sizeof(AuthToken) + toklen + 1);
    authtoken->string = (char *) authtoken + sizeof(AuthToken);
    authtoken->quoted = quoted;
    authtoken->regex = NULL;
    memcpy(authtoken->string, token, toklen + 1);
 
    return authtoken;
}
 
/*
 * Free an AuthToken, that may include a regular expression that needs
 * to be cleaned up explicitly.
 */
static void
free_auth_token(AuthToken *token)
{
    if (token_has_regexp(token))
        pg_regfree(token->regex);
}
 
/*
 * Copy a AuthToken struct into freshly palloc'd memory.
 */
static AuthToken *
copy_auth_token(AuthToken *in)
{
    AuthToken  *out = make_auth_token(in->string, in->quoted);
 
    return out;
}
 
/*
 * Compile the regular expression and store it in the AuthToken given in
 * input.  Returns the result of pg_regcomp().  On error, the details are
 * stored in "err_msg".
 */
static int
regcomp_auth_token(AuthToken *token, char *filename, int line_num,
                   char **err_msg, int elevel)
{
    pg_wchar   *wstr;
    int         wlen;
    int         rc;
 
    Assert(token->regex == NULL);
 
    if (token->string[0] != '/')
        return 0;               /* nothing to compile */
 
    token->regex = palloc0_object(regex_t);
    wstr = palloc((strlen(token->string + 1) + 1) * sizeof(pg_wchar));
    wlen = pg_mb2wchar_with_len(token->string + 1,
                                wstr, strlen(token->string + 1));
 
    rc = pg_regcomp(token->regex, wstr, wlen, REG_ADVANCED, C_COLLATION_OID);
 
    if (rc)
    {
        char        errstr[100];
 
        pg_regerror(rc, token->regex, errstr, sizeof(errstr));
        ereport(elevel,
                (errcode(ERRCODE_INVALID_REGULAR_EXPRESSION),
                 errmsg("invalid regular expression \"%s\": %s",
                        token->string + 1, errstr),
                 errcontext("line %d of configuration file \"%s\"",
                            line_num, filename)));
 
        *err_msg = psprintf("invalid regular expression \"%s\": %s",
                            token->string + 1, errstr);
    }
 
    pfree(wstr);
    return rc;
}
 
/*
 * Execute a regular expression computed in an AuthToken, checking for a match
 * with the string specified in "match".  The caller may optionally give an
 * array to store the matches.  Returns the result of pg_regexec().
 */
static int
regexec_auth_token(const char *match, AuthToken *token, size_t nmatch,
                   regmatch_t pmatch[])
{
    pg_wchar   *wmatchstr;
    int         wmatchlen;
    int         r;
 
    Assert(token->string[0] == '/' && token->regex);
 
    wmatchstr = palloc((strlen(match) + 1) * sizeof(pg_wchar));
    wmatchlen = pg_mb2wchar_with_len(match, wmatchstr, strlen(match));
 
    r = pg_regexec(token->regex, wmatchstr, wmatchlen, 0, NULL, nmatch, pmatch, 0);
 
    pfree(wmatchstr);
    return r;
}
 
/*
 * Tokenize one HBA field from a line, handling file inclusion and comma lists.
 *
 * filename: current file's pathname (needed to resolve relative pathnames)
 * *lineptr: current line pointer, which will be advanced past field
 *
 * In event of an error, log a message at ereport level elevel, and also
 * set *err_msg to a string describing the error.  Note that the result
 * may be non-NIL anyway, so *err_msg must be tested to determine whether
 * there was an error.
 *
 * The result is a List of AuthToken structs, one for each token in the field,
 * or NIL if we reached EOL.
 */
static List *
next_field_expand(const char *filename, char **lineptr,
                  int elevel, int depth, char **err_msg)
{
    StringInfoData buf;
    bool        trailing_comma;
    bool        initial_quote;
    List       *tokens = NIL;
 
    initStringInfo(&buf);
 
    do
    {
        if (!next_token(lineptr, &buf,
                        &initial_quote, &trailing_comma))
            break;
 
        /* Is this referencing a file? */
        if (!initial_quote && buf.len > 1 && buf.data[0] == '@')
            tokens = tokenize_expand_file(tokens, filename, buf.data + 1,
                                          elevel, depth + 1, err_msg);
        else
        {
            MemoryContext oldcxt;
 
            /*
             * lappend() may do its own allocations, so move to the context
             * for the list of tokens.
             */
            oldcxt = MemoryContextSwitchTo(tokenize_context);
            tokens = lappend(tokens, make_auth_token(buf.data, initial_quote));
            MemoryContextSwitchTo(oldcxt);
        }
    } while (trailing_comma && (*err_msg == NULL));
 
    pfree(buf.data);
 
    return tokens;
}
 
/*
 * tokenize_include_file
 *      Include a file from another file into an hba "field".
 *
 * Opens and tokenises a file included from another authentication file
 * with one of the include records ("include", "include_if_exists" or
 * "include_dir"), and assign all values found to an existing list of
 * list of AuthTokens.
 *
 * All new tokens are allocated in the memory context dedicated to the
 * tokenization, aka tokenize_context.
 *
 * If missing_ok is true, ignore a missing file.
 *
 * In event of an error, log a message at ereport level elevel, and also
 * set *err_msg to a string describing the error.  Note that the result
 * may be non-NIL anyway, so *err_msg must be tested to determine whether
 * there was an error.
 */
static void
tokenize_include_file(const char *outer_filename,
                      const char *inc_filename,
                      List **tok_lines,
                      int elevel,
                      int depth,
                      bool missing_ok,
                      char **err_msg)
{
    char       *inc_fullname;
    FILE       *inc_file;
 
    inc_fullname = AbsoluteConfigLocation(inc_filename, outer_filename);
    inc_file = open_auth_file(inc_fullname, elevel, depth, err_msg);
 
    if (!inc_file)
    {
        if (errno == ENOENT && missing_ok)
        {
            ereport(elevel,
                    (errmsg("skipping missing authentication file \"%s\"",
                            inc_fullname)));
            *err_msg = NULL;
            pfree(inc_fullname);
            return;
        }
 
        /* error in err_msg, so leave and report */
        pfree(inc_fullname);
        Assert(err_msg);
        return;
    }
 
    tokenize_auth_file(inc_fullname, inc_file, tok_lines, elevel,
                       depth);
    free_auth_file(inc_file, depth);
    pfree(inc_fullname);
}
 
/*
 * tokenize_expand_file
 *      Expand a file included from another file into an hba "field"
 *
 * Opens and tokenises a file included from another HBA config file with @,
 * and returns all values found therein as a flat list of AuthTokens.  If a
 * @-token or include record is found, recursively expand it.  The newly
 * read tokens are appended to "tokens" (so that foo,bar,@baz does what you
 * expect).  All new tokens are allocated in the memory context dedicated
 * to the list of TokenizedAuthLines, aka tokenize_context.
 *
 * In event of an error, log a message at ereport level elevel, and also
 * set *err_msg to a string describing the error.  Note that the result
 * may be non-NIL anyway, so *err_msg must be tested to determine whether
 * there was an error.
 */
static List *
tokenize_expand_file(List *tokens,
                     const char *outer_filename,
                     const char *inc_filename,
                     int elevel,
                     int depth,
                     char **err_msg)
{
    char       *inc_fullname;
    FILE       *inc_file;
    List       *inc_lines = NIL;
    ListCell   *inc_line;
 
    inc_fullname = AbsoluteConfigLocation(inc_filename, outer_filename);
    inc_file = open_auth_file(inc_fullname, elevel, depth, err_msg);
 
    if (inc_file == NULL)
    {
        /* error already logged */
        pfree(inc_fullname);
        return tokens;
    }
 
    /*
     * There is possible recursion here if the file contains @ or an include
     * record.
     */
    tokenize_auth_file(inc_fullname, inc_file, &inc_lines, elevel,
                       depth);
 
    pfree(inc_fullname);
 
    /*
     * Move all the tokens found in the file to the tokens list.  These are
     * already saved in tokenize_context.
     */
    foreach(inc_line, inc_lines)
    {
        TokenizedAuthLine *tok_line = (TokenizedAuthLine *) lfirst(inc_line);
        ListCell   *inc_field;
 
        /* If any line has an error, propagate that up to caller */
        if (tok_line->err_msg)
        {
            *err_msg = pstrdup(tok_line->err_msg);
            break;
        }
 
        foreach(inc_field, tok_line->fields)
        {
            List       *inc_tokens = lfirst(inc_field);
            ListCell   *inc_token;
 
            foreach(inc_token, inc_tokens)
            {
                AuthToken  *token = lfirst(inc_token);
                MemoryContext oldcxt;
 
                /*
                 * lappend() may do its own allocations, so move to the
                 * context for the list of tokens.
                 */
                oldcxt = MemoryContextSwitchTo(tokenize_context);
                tokens = lappend(tokens, token);
                MemoryContextSwitchTo(oldcxt);
            }
        }
    }
 
    free_auth_file(inc_file, depth);
    return tokens;
}
 
/*
 * free_auth_file
 *      Free a file opened by open_auth_file().
 */
void
free_auth_file(FILE *file, int depth)
{
    FreeFile(file);
 
    /* If this is the last cleanup, remove the tokenization context */
    if (depth == CONF_FILE_START_DEPTH)
    {
        MemoryContextDelete(tokenize_context);
        tokenize_context = NULL;
    }
}
 
/*
 * open_auth_file
 *      Open the given file.
 *
 * filename: the absolute path to the target file
 * elevel: message logging level
 * depth: recursion level when opening the file
 * err_msg: details about the error
 *
 * Return value is the opened file.  On error, returns NULL with details
 * about the error stored in "err_msg".
 */
FILE *
open_auth_file(const char *filename, int elevel, int depth,
               char **err_msg)
{
    FILE       *file;
 
    /*
     * Reject too-deep include nesting depth.  This is just a safety check to
     * avoid dumping core due to stack overflow if an include file loops back
     * to itself.  The maximum nesting depth is pretty arbitrary.
     */
    if (depth > CONF_FILE_MAX_DEPTH)
    {
        ereport(elevel,
                (errcode_for_file_access(),
                 errmsg("could not open file \"%s\": maximum nesting depth exceeded",
                        filename)));
        if (err_msg)
            *err_msg = psprintf("could not open file \"%s\": maximum nesting depth exceeded",
                                filename);
        return NULL;
    }
 
    file = AllocateFile(filename, "r");
    if (file == NULL)
    {
        int         save_errno = errno;
 
        ereport(elevel,
                (errcode_for_file_access(),
                 errmsg("could not open file \"%s\": %m",
                        filename)));
        if (err_msg)
        {
            errno = save_errno;
            *err_msg = psprintf("could not open file \"%s\": %m",
                                filename);
        }
        /* the caller may care about some specific errno */
        errno = save_errno;
        return NULL;
    }
 
    /*
     * When opening the top-level file, create the memory context used for the
     * tokenization.  This will be closed with this file when coming back to
     * this level of cleanup.
     */
    if (depth == CONF_FILE_START_DEPTH)
    {
        /*
         * A context may be present, but assume that it has been eliminated
         * already.
         */
        tokenize_context = AllocSetContextCreate(CurrentMemoryContext,
                                                 "tokenize_context",
                                                 ALLOCSET_START_SMALL_SIZES);
    }
 
    return file;
}
 
/*
 * error context callback for tokenize_auth_file()
 */
static void
tokenize_error_callback(void *arg)
{
    tokenize_error_callback_arg *callback_arg = (tokenize_error_callback_arg *) arg;
 
    errcontext("line %d of configuration file \"%s\"",
               callback_arg->linenum, callback_arg->filename);
}
 
/*
 * tokenize_auth_file
 *      Tokenize the given file.
 *
 * The output is a list of TokenizedAuthLine structs; see the struct definition
 * in libpq/hba.h.  This is the central piece in charge of parsing the
 * authentication files.  All the operations of this function happen in its own
 * local memory context, easing the cleanup of anything allocated here.  This
 * matters a lot when reloading authentication files in the postmaster.
 *
 * filename: the absolute path to the target file
 * file: the already-opened target file
 * tok_lines: receives output list, saved into tokenize_context
 * elevel: message logging level
 * depth: level of recursion when tokenizing the target file
 *
 * Errors are reported by logging messages at ereport level elevel and by
 * adding TokenizedAuthLine structs containing non-null err_msg fields to the
 * output list.
 */
void
tokenize_auth_file(const char *filename, FILE *file, List **tok_lines,
                   int elevel, int depth)
{
    int         line_number = 1;
    StringInfoData buf;
    MemoryContext linecxt;
    MemoryContext funccxt;      /* context of this function's caller */
    ErrorContextCallback tokenerrcontext;
    tokenize_error_callback_arg callback_arg;
 
    Assert(tokenize_context);
 
    callback_arg.filename = filename;
    callback_arg.linenum = line_number;
 
    tokenerrcontext.callback = tokenize_error_callback;
    tokenerrcontext.arg = &callback_arg;
    tokenerrcontext.previous = error_context_stack;
    error_context_stack = &tokenerrcontext;
 
    /*
     * Do all the local tokenization in its own context, to ease the cleanup
     * of any memory allocated while tokenizing.
     */
    linecxt = AllocSetContextCreate(CurrentMemoryContext,
                                    "tokenize_auth_file",
                                    ALLOCSET_SMALL_SIZES);
    funccxt = MemoryContextSwitchTo(linecxt);
 
    initStringInfo(&buf);
 
    if (depth == CONF_FILE_START_DEPTH)
        *tok_lines = NIL;
 
    while (!feof(file) && !ferror(file))
    {
        TokenizedAuthLine *tok_line;
        MemoryContext oldcxt;
        char       *lineptr;
        List       *current_line = NIL;
        char       *err_msg = NULL;
        int         last_backslash_buflen = 0;
        int         continuations = 0;
 
        /* Collect the next input line, handling backslash continuations */
        resetStringInfo(&buf);
 
        while (pg_get_line_append(file, &buf, NULL))
        {
            /* Strip trailing newline, including \r in case we're on Windows */
            buf.len = pg_strip_crlf(buf.data);
 
            /*
             * Check for backslash continuation.  The backslash must be after
             * the last place we found a continuation, else two backslashes
             * followed by two \n's would behave surprisingly.
             */
            if (buf.len > last_backslash_buflen &&
                buf.data[buf.len - 1] == '\\')
            {
                /* Continuation, so strip it and keep reading */
                buf.data[--buf.len] = '\0';
                last_backslash_buflen = buf.len;
                continuations++;
                continue;
            }
 
            /* Nope, so we have the whole line */
            break;
        }
 
        if (ferror(file))
        {
            /* I/O error! */
            int         save_errno = errno;
 
            ereport(elevel,
                    (errcode_for_file_access(),
                     errmsg("could not read file \"%s\": %m", filename)));
            errno = save_errno;
            err_msg = psprintf("could not read file \"%s\": %m",
                               filename);
            break;
        }
 
        /* Parse fields */
        lineptr = buf.data;
        while (*lineptr && err_msg == NULL)
        {
            List       *current_field;
 
            current_field = next_field_expand(filename, &lineptr,
                                              elevel, depth, &err_msg);
            /* add field to line, unless we are at EOL or comment start */
            if (current_field != NIL)
            {
                /*
                 * lappend() may do its own allocations, so move to the
                 * context for the list of tokens.
                 */
                oldcxt = MemoryContextSwitchTo(tokenize_context);
                current_line = lappend(current_line, current_field);
                MemoryContextSwitchTo(oldcxt);
            }
        }
 
        /*
         * Reached EOL; no need to emit line to TokenizedAuthLine list if it's
         * boring.
         */
        if (current_line == NIL && err_msg == NULL)
            goto next_line;
 
        /* If the line is valid, check if that's an include directive */
        if (err_msg == NULL && list_length(current_line) == 2)
        {
            AuthToken  *first,
                       *second;
 
            first = linitial(linitial_node(List, current_line));
            second = linitial(lsecond_node(List, current_line));
 
            if (strcmp(first->string, "include") == 0)
            {
                tokenize_include_file(filename, second->string, tok_lines,
                                      elevel, depth + 1, false, &err_msg);
 
                if (err_msg)
                    goto process_line;
 
                /*
                 * tokenize_auth_file() has taken care of creating the
                 * TokenizedAuthLines.
                 */
                goto next_line;
            }
            else if (strcmp(first->string, "include_dir") == 0)
            {
                char      **filenames;
                char       *dir_name = second->string;
                int         num_filenames;
                StringInfoData err_buf;
 
                filenames = GetConfFilesInDir(dir_name, filename, elevel,
                                              &num_filenames, &err_msg);
 
                if (!filenames)
                {
                    /* the error is in err_msg, so create an entry */
                    goto process_line;
                }
 
                initStringInfo(&err_buf);
                for (int i = 0; i < num_filenames; i++)
                {
                    tokenize_include_file(filename, filenames[i], tok_lines,
                                          elevel, depth + 1, false, &err_msg);
                    /* cumulate errors if any */
                    if (err_msg)
                    {
                        if (err_buf.len > 0)
                            appendStringInfoChar(&err_buf, '\n');
                        appendStringInfoString(&err_buf, err_msg);
                    }
                }
 
                /* clean up things */
                for (int i = 0; i < num_filenames; i++)
                    pfree(filenames[i]);
                pfree(filenames);
 
                /*
                 * If there were no errors, the line is fully processed,
                 * bypass the general TokenizedAuthLine processing.
                 */
                if (err_buf.len == 0)
                    goto next_line;
 
                /* Otherwise, process the cumulated errors, if any. */
                err_msg = err_buf.data;
                goto process_line;
            }
            else if (strcmp(first->string, "include_if_exists") == 0)
            {
 
                tokenize_include_file(filename, second->string, tok_lines,
                                      elevel, depth + 1, true, &err_msg);
                if (err_msg)
                    goto process_line;
 
                /*
                 * tokenize_auth_file() has taken care of creating the
                 * TokenizedAuthLines.
                 */
                goto next_line;
            }
        }
 
process_line:
 
        /*
         * General processing: report the error if any and emit line to the
         * TokenizedAuthLine.  This is saved in the memory context dedicated
         * to this list.
         */
        oldcxt = MemoryContextSwitchTo(tokenize_context);
        tok_line = palloc0_object(TokenizedAuthLine);
        tok_line->fields = current_line;
        tok_line->file_name = pstrdup(filename);
        tok_line->line_num = line_number;
        tok_line->raw_line = pstrdup(buf.data);
        tok_line->err_msg = err_msg ? pstrdup(err_msg) : NULL;
        *tok_lines = lappend(*tok_lines, tok_line);
        MemoryContextSwitchTo(oldcxt);
 
next_line:
        line_number += continuations + 1;
        callback_arg.linenum = line_number;
    }
 
    MemoryContextSwitchTo(funccxt);
    MemoryContextDelete(linecxt);
 
    error_context_stack = tokenerrcontext.previous;
}
 
 
/*
 * Does user belong to role?
 *
 * userid is the OID of the role given as the attempted login identifier.
 * We check to see if it is a member of the specified role name.
 */
static bool
is_member(Oid userid, const char *role)
{
    Oid         roleid;
 
    if (!OidIsValid(userid))
        return false;           /* if user not exist, say "no" */
 
    roleid = get_role_oid(role, true);
 
    if (!OidIsValid(roleid))
        return false;           /* if target role not exist, say "no" */
 
    /*
     * See if user is directly or indirectly a member of role. For this
     * purpose, a superuser is not considered to be automatically a member of
     * the role, so group auth only applies to explicit membership.
     */
    return is_member_of_role_nosuper(userid, roleid);
}
 
/*
 * Check AuthToken list for a match to role, allowing group names.
 *
 * Each AuthToken listed is checked one-by-one.  Keywords are processed
 * first (these cannot have regular expressions), followed by regular
 * expressions (if any), the case-insensitive match (if requested) and
 * the exact match.
 */
static bool
check_role(const char *role, Oid roleid, List *tokens, bool case_insensitive)
{
    ListCell   *cell;
    AuthToken  *tok;
 
    foreach(cell, tokens)
    {
        tok = lfirst(cell);
        if (token_is_member_check(tok))
        {
            if (is_member(roleid, tok->string + 1))
                return true;
        }
        else if (token_is_keyword(tok, "all"))
            return true;
        else if (token_has_regexp(tok))
        {
            if (regexec_auth_token(role, tok, 0, NULL) == REG_OKAY)
                return true;
        }
        else if (case_insensitive)
        {
            if (token_matches_insensitive(tok, role))
                return true;
        }
        else if (token_matches(tok, role))
            return true;
    }
    return false;
}
 
/*
 * Check to see if db/role combination matches AuthToken list.
 *
 * Each AuthToken listed is checked one-by-one.  Keywords are checked
 * first (these cannot have regular expressions), followed by regular
 * expressions (if any) and the exact match.
 */
static bool
check_db(const char *dbname, const char *role, Oid roleid, List *tokens)
{
    ListCell   *cell;
    AuthToken  *tok;
 
    foreach(cell, tokens)
    {
        tok = lfirst(cell);
        if (am_walsender && !am_db_walsender)
        {
            /*
             * physical replication walsender connections can only match
             * replication keyword
             */
            if (token_is_keyword(tok, "replication"))
                return true;
        }
        else if (token_is_keyword(tok, "all"))
            return true;
        else if (token_is_keyword(tok, "sameuser"))
        {
            if (strcmp(dbname, role) == 0)
                return true;
        }
        else if (token_is_keyword(tok, "samegroup") ||
                 token_is_keyword(tok, "samerole"))
        {
            if (is_member(roleid, dbname))
                return true;
        }
        else if (token_is_keyword(tok, "replication"))
            continue;           /* never match this if not walsender */
        else if (token_has_regexp(tok))
        {
            if (regexec_auth_token(dbname, tok, 0, NULL) == REG_OKAY)
                return true;
        }
        else if (token_matches(tok, dbname))
            return true;
    }
    return false;
}
 
static bool
ipv4eq(struct sockaddr_in *a, struct sockaddr_in *b)
{
    return (a->sin_addr.s_addr == b->sin_addr.s_addr);
}
 
static bool
ipv6eq(struct sockaddr_in6 *a, struct sockaddr_in6 *b)
{
    int         i;
 
    for (i = 0; i < 16; i++)
        if (a->sin6_addr.s6_addr[i] != b->sin6_addr.s6_addr[i])
            return false;
 
    return true;
}
 
/*
 * Check whether host name matches pattern.
 */
static bool
hostname_match(const char *pattern, const char *actual_hostname)
{
    if (pattern[0] == '.')      /* suffix match */
    {
        size_t      plen = strlen(pattern);
        size_t      hlen = strlen(actual_hostname);
 
        if (hlen < plen)
            return false;
 
        return (pg_strcasecmp(pattern, actual_hostname + (hlen - plen)) == 0);
    }
    else
        return (pg_strcasecmp(pattern, actual_hostname) == 0);
}
 
/*
 * Check to see if a connecting IP matches a given host name.
 */
static bool
check_hostname(Port *port, const char *hostname)
{
    struct addrinfo *gai_result,
               *gai;
    int         ret;
    bool        found;
 
    /* Quick out if remote host name already known bad */
    if (port->remote_hostname_resolv < 0)
        return false;
 
    /* Lookup remote host name if not already done */
    if (!port->remote_hostname)
    {
        char        remote_hostname[NI_MAXHOST];
 
        ret = pg_getnameinfo_all(&port->raddr.addr, port->raddr.salen,
                                 remote_hostname, sizeof(remote_hostname),
                                 NULL, 0,
                                 NI_NAMEREQD);
        if (ret != 0)
        {
            /* remember failure; don't complain in the postmaster log yet */
            port->remote_hostname_resolv = -2;
            port->remote_hostname_errcode = ret;
            return false;
        }
 
        port->remote_hostname = pstrdup(remote_hostname);
    }
 
    /* Now see if remote host name matches this pg_hba line */
    if (!hostname_match(hostname, port->remote_hostname))
        return false;
 
    /* If we already verified the forward lookup, we're done */
    if (port->remote_hostname_resolv == +1)
        return true;
 
    /* Lookup IP from host name and check against original IP */
    ret = getaddrinfo(port->remote_hostname, NULL, NULL, &gai_result);
    if (ret != 0)
    {
        /* remember failure; don't complain in the postmaster log yet */
        port->remote_hostname_resolv = -2;
        port->remote_hostname_errcode = ret;
        return false;
    }
 
    found = false;
    for (gai = gai_result; gai; gai = gai->ai_next)
    {
        if (gai->ai_addr->sa_family == port->raddr.addr.ss_family)
        {
            if (gai->ai_addr->sa_family == AF_INET)
            {
                if (ipv4eq((struct sockaddr_in *) gai->ai_addr,
                           (struct sockaddr_in *) &port->raddr.addr))
                {
                    found = true;
                    break;
                }
            }
            else if (gai->ai_addr->sa_family == AF_INET6)
            {
                if (ipv6eq((struct sockaddr_in6 *) gai->ai_addr,
                           (struct sockaddr_in6 *) &port->raddr.addr))
                {
                    found = true;
                    break;
                }
            }
        }
    }
 
    if (gai_result)
        freeaddrinfo(gai_result);
 
    if (!found)
        elog(DEBUG2, "pg_hba.conf host name \"%s\" rejected because address resolution did not return a match with IP address of client",
             hostname);
 
    port->remote_hostname_resolv = found ? +1 : -1;
 
    return found;
}
 
/*
 * Check to see if a connecting IP matches the given address and netmask.
 */
static bool
check_ip(SockAddr *raddr, struct sockaddr *addr, struct sockaddr *mask)
{
    if (raddr->addr.ss_family == addr->sa_family &&
        pg_range_sockaddr(&raddr->addr,
                          (struct sockaddr_storage *) addr,
                          (struct sockaddr_storage *) mask))
        return true;
    return false;
}
 
/*
 * pg_foreach_ifaddr callback: does client addr match this machine interface?
 */
static void
check_network_callback(struct sockaddr *addr, struct sockaddr *netmask,
                       void *cb_data)
{
    check_network_data *cn = (check_network_data *) cb_data;
    struct sockaddr_storage mask;
 
    /* Already found a match? */
    if (cn->result)
        return;
 
    if (cn->method == ipCmpSameHost)
    {
        /* Make an all-ones netmask of appropriate length for family */
        pg_sockaddr_cidr_mask(&mask, NULL, addr->sa_family);
        cn->result = check_ip(cn->raddr, addr, (struct sockaddr *) &mask);
    }
    else
    {
        /* Use the netmask of the interface itself */
        cn->result = check_ip(cn->raddr, addr, netmask);
    }
}
 
/*
 * Use pg_foreach_ifaddr to check a samehost or samenet match
 */
static bool
check_same_host_or_net(SockAddr *raddr, IPCompareMethod method)
{
    check_network_data cn;
 
    cn.method = method;
    cn.raddr = raddr;
    cn.result = false;
 
    errno = 0;
    if (pg_foreach_ifaddr(check_network_callback, &cn) < 0)
    {
        ereport(LOG,
                (errmsg("error enumerating network interfaces: %m")));
        return false;
    }
 
    return cn.result;
}
 
 
/*
 * Macros used to check and report on invalid configuration options.
 * On error: log a message at level elevel, set *err_msg, and exit the function.
 * These macros are not as general-purpose as they look, because they know
 * what the calling function's error-exit value is.
 *
 * INVALID_AUTH_OPTION = reports when an option is specified for a method where it's
 *                       not supported.
 * REQUIRE_AUTH_OPTION = same as INVALID_AUTH_OPTION, except it also checks if the
 *                       method is actually the one specified. Used as a shortcut when
 *                       the option is only valid for one authentication method.
 * MANDATORY_AUTH_ARG  = check if a required option is set for an authentication method,
 *                       reporting error if it's not.
 */
#define INVALID_AUTH_OPTION(optname, validmethods) \
do { \
    ereport(elevel, \
            (errcode(ERRCODE_CONFIG_FILE_ERROR), \
             /* translator: the second %s is a list of auth methods */ \
             errmsg("authentication option \"%s\" is only valid for authentication methods %s", \
                    optname, _(validmethods)), \
             errcontext("line %d of configuration file \"%s\"", \
                    line_num, file_name))); \
    *err_msg = psprintf("authentication option \"%s\" is only valid for authentication methods %s", \
                        optname, validmethods); \
    return false; \
} while (0)
 
#define REQUIRE_AUTH_OPTION(methodval, optname, validmethods) \
do { \
    if (hbaline->auth_method != methodval) \
        INVALID_AUTH_OPTION(optname, validmethods); \
} while (0)
 
#define MANDATORY_AUTH_ARG(argvar, argname, authname) \
do { \
    if (argvar == NULL) { \
        ereport(elevel, \
                (errcode(ERRCODE_CONFIG_FILE_ERROR), \
                 errmsg("authentication method \"%s\" requires argument \"%s\" to be set", \
                        authname, argname), \
                 errcontext("line %d of configuration file \"%s\"", \
                        line_num, file_name))); \
        *err_msg = psprintf("authentication method \"%s\" requires argument \"%s\" to be set", \
                            authname, argname); \
        return NULL; \
    } \
} while (0)
 
/*
 * Macros for handling pg_ident problems, similar as above.
 *
 * IDENT_FIELD_ABSENT:
 * Reports when the given ident field ListCell is not populated.
 *
 * IDENT_MULTI_VALUE:
 * Reports when the given ident token List has more than one element.
 */
#define IDENT_FIELD_ABSENT(field) \
do { \
    if (!field) { \
        ereport(elevel, \
                (errcode(ERRCODE_CONFIG_FILE_ERROR), \
                 errmsg("missing entry at end of line"), \
                 errcontext("line %d of configuration file \"%s\"", \
                            line_num, file_name))); \
        *err_msg = pstrdup("missing entry at end of line"); \
        return NULL; \
    } \
} while (0)
 
#define IDENT_MULTI_VALUE(tokens) \
do { \
    if (tokens->length > 1) { \
        ereport(elevel, \
                (errcode(ERRCODE_CONFIG_FILE_ERROR), \
                 errmsg("multiple values in ident field"), \
                 errcontext("line %d of configuration file \"%s\"", \
                            line_num, file_name))); \
        *err_msg = pstrdup("multiple values in ident field"); \
        return NULL; \
    } \
} while (0)
 
 
/*
 * Parse one tokenised line from the hba config file and store the result in a
 * HbaLine structure.
 *
 * If parsing fails, log a message at ereport level elevel, store an error
 * string in tok_line->err_msg, and return NULL.  (Some non-error conditions
 * can also result in such messages.)
 *
 * Note: this function leaks memory when an error occurs.  Caller is expected
 * to have set a memory context that will be reset if this function returns
 * NULL.
 */
HbaLine *
parse_hba_line(TokenizedAuthLine *tok_line, int elevel)
{
    int         line_num = tok_line->line_num;
    char       *file_name = tok_line->file_name;
    char      **err_msg = &tok_line->err_msg;
    char       *str;
    struct addrinfo *gai_result;
    struct addrinfo hints;
    int         ret;
    char       *cidr_slash;
    char       *unsupauth;
    ListCell   *field;
    List       *tokens;
    ListCell   *tokencell;
    AuthToken  *token;
    HbaLine    *parsedline;
 
    parsedline = palloc0_object(HbaLine);
    parsedline->sourcefile = pstrdup(file_name);
    parsedline->linenumber = line_num;
    parsedline->rawline = pstrdup(tok_line->raw_line);
 
    /* Check the record type. */
    Assert(tok_line->fields != NIL);
    field = list_head(tok_line->fields);
    tokens = lfirst(field);
    if (tokens->length > 1)
    {
        ereport(elevel,
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("multiple values specified for connection type"),
                 errhint("Specify exactly one connection type per line."),
                 errcontext("line %d of configuration file \"%s\"",
                            line_num, file_name)));
        *err_msg = "multiple values specified for connection type";
        return NULL;
    }
    token = linitial(tokens);
    if (strcmp(token->string, "local") == 0)
    {
        parsedline->conntype = ctLocal;
    }
    else if (strcmp(token->string, "host") == 0 ||
             strcmp(token->string, "hostssl") == 0 ||
             strcmp(token->string, "hostnossl") == 0 ||
             strcmp(token->string, "hostgssenc") == 0 ||
             strcmp(token->string, "hostnogssenc") == 0)
    {
 
        if (token->string[4] == 's')    /* "hostssl" */
        {
            parsedline->conntype = ctHostSSL;
            /* Log a warning if SSL support is not active */
#ifdef USE_SSL
            if (!EnableSSL)
            {
                ereport(elevel,
                        (errcode(ERRCODE_CONFIG_FILE_ERROR),
                         errmsg("hostssl record cannot match because SSL is disabled"),
                         errhint("Set \"ssl = on\" in postgresql.conf."),
                         errcontext("line %d of configuration file \"%s\"",
                                    line_num, file_name)));
                *err_msg = "hostssl record cannot match because SSL is disabled";
            }
#else
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("hostssl record cannot match because SSL is not supported by this build"),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, file_name)));
            *err_msg = "hostssl record cannot match because SSL is not supported by this build";
#endif
        }
        else if (token->string[4] == 'g')   /* "hostgssenc" */
        {
            parsedline->conntype = ctHostGSS;
#ifndef ENABLE_GSS
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("hostgssenc record cannot match because GSSAPI is not supported by this build"),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, file_name)));
            *err_msg = "hostgssenc record cannot match because GSSAPI is not supported by this build";
#endif
        }
        else if (token->string[4] == 'n' && token->string[6] == 's')
            parsedline->conntype = ctHostNoSSL;
        else if (token->string[4] == 'n' && token->string[6] == 'g')
            parsedline->conntype = ctHostNoGSS;
        else
        {
            /* "host" */
            parsedline->conntype = ctHost;
        }
    }                           /* record type */
    else
    {
        ereport(elevel,
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("invalid connection type \"%s\"",
                        token->string),
                 errcontext("line %d of configuration file \"%s\"",
                            line_num, file_name)));
        *err_msg = psprintf("invalid connection type \"%s\"", token->string);
        return NULL;
    }
 
    /* Get the databases. */
    field = lnext(tok_line->fields, field);
    if (!field)
    {
        ereport(elevel,
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("end-of-line before database specification"),
                 errcontext("line %d of configuration file \"%s\"",
                            line_num, file_name)));
        *err_msg = "end-of-line before database specification";
        return NULL;
    }
    parsedline->databases = NIL;
    tokens = lfirst(field);
    foreach(tokencell, tokens)
    {
        AuthToken  *tok = copy_auth_token(lfirst(tokencell));
 
        /* Compile a regexp for the database token, if necessary */
        if (regcomp_auth_token(tok, file_name, line_num, err_msg, elevel))
            return NULL;
 
        parsedline->databases = lappend(parsedline->databases, tok);
    }
 
    /* Get the roles. */
    field = lnext(tok_line->fields, field);
    if (!field)
    {
        ereport(elevel,
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("end-of-line before role specification"),
                 errcontext("line %d of configuration file \"%s\"",
                            line_num, file_name)));
        *err_msg = "end-of-line before role specification";
        return NULL;
    }
    parsedline->roles = NIL;
    tokens = lfirst(field);
    foreach(tokencell, tokens)
    {
        AuthToken  *tok = copy_auth_token(lfirst(tokencell));
 
        /* Compile a regexp from the role token, if necessary */
        if (regcomp_auth_token(tok, file_name, line_num, err_msg, elevel))
            return NULL;
 
        parsedline->roles = lappend(parsedline->roles, tok);
    }
 
    if (parsedline->conntype != ctLocal)
    {
        /* Read the IP address field. (with or without CIDR netmask) */
        field = lnext(tok_line->fields, field);
        if (!field)
        {
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("end-of-line before IP address specification"),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, file_name)));
            *err_msg = "end-of-line before IP address specification";
            return NULL;
        }
        tokens = lfirst(field);
        if (tokens->length > 1)
        {
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("multiple values specified for host address"),
                     errhint("Specify one address range per line."),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, file_name)));
            *err_msg = "multiple values specified for host address";
            return NULL;
        }
        token = linitial(tokens);
 
        if (token_is_keyword(token, "all"))
        {
            parsedline->ip_cmp_method = ipCmpAll;
        }
        else if (token_is_keyword(token, "samehost"))
        {
            /* Any IP on this host is allowed to connect */
            parsedline->ip_cmp_method = ipCmpSameHost;
        }
        else if (token_is_keyword(token, "samenet"))
        {
            /* Any IP on the host's subnets is allowed to connect */
            parsedline->ip_cmp_method = ipCmpSameNet;
        }
        else
        {
            /* IP and netmask are specified */
            parsedline->ip_cmp_method = ipCmpMask;
 
            /* need a modifiable copy of token */
            str = pstrdup(token->string);
 
            /* Check if it has a CIDR suffix and if so isolate it */
            cidr_slash = strchr(str, '/');
            if (cidr_slash)
                *cidr_slash = '\0';
 
            /* Get the IP address either way */
            hints.ai_flags = AI_NUMERICHOST;
            hints.ai_family = AF_UNSPEC;
            hints.ai_socktype = 0;
            hints.ai_protocol = 0;
            hints.ai_addrlen = 0;
            hints.ai_canonname = NULL;
            hints.ai_addr = NULL;
            hints.ai_next = NULL;
 
            ret = pg_getaddrinfo_all(str, NULL, &hints, &gai_result);
            if (ret == 0 && gai_result)
            {
                memcpy(&parsedline->addr, gai_result->ai_addr,
                       gai_result->ai_addrlen);
                parsedline->addrlen = gai_result->ai_addrlen;
            }
            else if (ret == EAI_NONAME)
                parsedline->hostname = str;
            else
            {
                ereport(elevel,
                        (errcode(ERRCODE_CONFIG_FILE_ERROR),
                         errmsg("invalid IP address \"%s\": %s",
                                str, gai_strerror(ret)),
                         errcontext("line %d of configuration file \"%s\"",
                                    line_num, file_name)));
                *err_msg = psprintf("invalid IP address \"%s\": %s",
                                    str, gai_strerror(ret));
                if (gai_result)
                    pg_freeaddrinfo_all(hints.ai_family, gai_result);
                return NULL;
            }
 
            pg_freeaddrinfo_all(hints.ai_family, gai_result);
 
            /* Get the netmask */
            if (cidr_slash)
            {
                if (parsedline->hostname)
                {
                    ereport(elevel,
                            (errcode(ERRCODE_CONFIG_FILE_ERROR),
                             errmsg("specifying both host name and CIDR mask is invalid: \"%s\"",
                                    token->string),
                             errcontext("line %d of configuration file \"%s\"",
                                        line_num, file_name)));
                    *err_msg = psprintf("specifying both host name and CIDR mask is invalid: \"%s\"",
                                        token->string);
                    return NULL;
                }
 
                if (pg_sockaddr_cidr_mask(&parsedline->mask, cidr_slash + 1,
                                          parsedline->addr.ss_family) < 0)
                {
                    ereport(elevel,
                            (errcode(ERRCODE_CONFIG_FILE_ERROR),
                             errmsg("invalid CIDR mask in address \"%s\"",
                                    token->string),
                             errcontext("line %d of configuration file \"%s\"",
                                        line_num, file_name)));
                    *err_msg = psprintf("invalid CIDR mask in address \"%s\"",
                                        token->string);
                    return NULL;
                }
                parsedline->masklen = parsedline->addrlen;
                pfree(str);
            }
            else if (!parsedline->hostname)
            {
                /* Read the mask field. */
                pfree(str);
                field = lnext(tok_line->fields, field);
                if (!field)
                {
                    ereport(elevel,
                            (errcode(ERRCODE_CONFIG_FILE_ERROR),
                             errmsg("end-of-line before netmask specification"),
                             errhint("Specify an address range in CIDR notation, or provide a separate netmask."),
                             errcontext("line %d of configuration file \"%s\"",
                                        line_num, file_name)));
                    *err_msg = "end-of-line before netmask specification";
                    return NULL;
                }
                tokens = lfirst(field);
                if (tokens->length > 1)
                {
                    ereport(elevel,
                            (errcode(ERRCODE_CONFIG_FILE_ERROR),
                             errmsg("multiple values specified for netmask"),
                             errcontext("line %d of configuration file \"%s\"",
                                        line_num, file_name)));
                    *err_msg = "multiple values specified for netmask";
                    return NULL;
                }
                token = linitial(tokens);
 
                ret = pg_getaddrinfo_all(token->string, NULL,
                                         &hints, &gai_result);
                if (ret || !gai_result)
                {
                    ereport(elevel,
                            (errcode(ERRCODE_CONFIG_FILE_ERROR),
                             errmsg("invalid IP mask \"%s\": %s",
                                    token->string, gai_strerror(ret)),
                             errcontext("line %d of configuration file \"%s\"",
                                        line_num, file_name)));
                    *err_msg = psprintf("invalid IP mask \"%s\": %s",
                                        token->string, gai_strerror(ret));
                    if (gai_result)
                        pg_freeaddrinfo_all(hints.ai_family, gai_result);
                    return NULL;
                }
 
                memcpy(&parsedline->mask, gai_result->ai_addr,
                       gai_result->ai_addrlen);
                parsedline->masklen = gai_result->ai_addrlen;
                pg_freeaddrinfo_all(hints.ai_family, gai_result);
 
                if (parsedline->addr.ss_family != parsedline->mask.ss_family)
                {
                    ereport(elevel,
                            (errcode(ERRCODE_CONFIG_FILE_ERROR),
                             errmsg("IP address and mask do not match"),
                             errcontext("line %d of configuration file \"%s\"",
                                        line_num, file_name)));
                    *err_msg = "IP address and mask do not match";
                    return NULL;
                }
            }
        }
    }                           /* != ctLocal */
 
    /* Get the authentication method */
    field = lnext(tok_line->fields, field);
    if (!field)
    {
        ereport(elevel,
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("end-of-line before authentication method"),
                 errcontext("line %d of configuration file \"%s\"",
                            line_num, file_name)));
        *err_msg = "end-of-line before authentication method";
        return NULL;
    }
    tokens = lfirst(field);
    if (tokens->length > 1)
    {
        ereport(elevel,
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("multiple values specified for authentication type"),
                 errhint("Specify exactly one authentication type per line."),
                 errcontext("line %d of configuration file \"%s\"",
                            line_num, file_name)));
        *err_msg = "multiple values specified for authentication type";
        return NULL;
    }
    token = linitial(tokens);
 
    unsupauth = NULL;
    if (strcmp(token->string, "trust") == 0)
        parsedline->auth_method = uaTrust;
    else if (strcmp(token->string, "ident") == 0)
        parsedline->auth_method = uaIdent;
    else if (strcmp(token->string, "peer") == 0)
        parsedline->auth_method = uaPeer;
    else if (strcmp(token->string, "password") == 0)
        parsedline->auth_method = uaPassword;
    else if (strcmp(token->string, "gss") == 0)
#ifdef ENABLE_GSS
        parsedline->auth_method = uaGSS;
#else
        unsupauth = "gss";
#endif
    else if (strcmp(token->string, "sspi") == 0)
#ifdef ENABLE_SSPI
        parsedline->auth_method = uaSSPI;
#else
        unsupauth = "sspi";
#endif
    else if (strcmp(token->string, "reject") == 0)
        parsedline->auth_method = uaReject;
    else if (strcmp(token->string, "md5") == 0)
        parsedline->auth_method = uaMD5;
    else if (strcmp(token->string, "scram-sha-256") == 0)
        parsedline->auth_method = uaSCRAM;
    else if (strcmp(token->string, "pam") == 0)
#ifdef USE_PAM
        parsedline->auth_method = uaPAM;
#else
        unsupauth = "pam";
#endif
    else if (strcmp(token->string, "bsd") == 0)
#ifdef USE_BSD_AUTH
        parsedline->auth_method = uaBSD;
#else
        unsupauth = "bsd";
#endif
    else if (strcmp(token->string, "ldap") == 0)
#ifdef USE_LDAP
        parsedline->auth_method = uaLDAP;
#else
        unsupauth = "ldap";
#endif
    else if (strcmp(token->string, "cert") == 0)
#ifdef USE_SSL
        parsedline->auth_method = uaCert;
#else
        unsupauth = "cert";
#endif
    else if (strcmp(token->string, "radius") == 0)
        parsedline->auth_method = uaRADIUS;
    else if (strcmp(token->string, "oauth") == 0)
        parsedline->auth_method = uaOAuth;
    else
    {
        ereport(elevel,
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("invalid authentication method \"%s\"",
                        token->string),
                 errcontext("line %d of configuration file \"%s\"",
                            line_num, file_name)));
        *err_msg = psprintf("invalid authentication method \"%s\"",
                            token->string);
        return NULL;
    }
 
    if (unsupauth)
    {
        ereport(elevel,
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("invalid authentication method \"%s\": not supported by this build",
                        token->string),
                 errcontext("line %d of configuration file \"%s\"",
                            line_num, file_name)));
        *err_msg = psprintf("invalid authentication method \"%s\": not supported by this build",
                            token->string);
        return NULL;
    }
 
    /*
     * XXX: When using ident on local connections, change it to peer, for
     * backwards compatibility.
     */
    if (parsedline->conntype == ctLocal &&
        parsedline->auth_method == uaIdent)
        parsedline->auth_method = uaPeer;
 
    /* Invalid authentication combinations */
    if (parsedline->conntype == ctLocal &&
        parsedline->auth_method == uaGSS)
    {
        ereport(elevel,
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("gssapi authentication is not supported on local sockets"),
                 errcontext("line %d of configuration file \"%s\"",
                            line_num, file_name)));
        *err_msg = "gssapi authentication is not supported on local sockets";
        return NULL;
    }
 
    if (parsedline->conntype != ctLocal &&
        parsedline->auth_method == uaPeer)
    {
        ereport(elevel,
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("peer authentication is only supported on local sockets"),
                 errcontext("line %d of configuration file \"%s\"",
                            line_num, file_name)));
        *err_msg = "peer authentication is only supported on local sockets";
        return NULL;
    }
 
    /*
     * SSPI authentication can never be enabled on ctLocal connections,
     * because it's only supported on Windows, where ctLocal isn't supported.
     */
 
 
    if (parsedline->conntype != ctHostSSL &&
        parsedline->auth_method == uaCert)
    {
        ereport(elevel,
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("cert authentication is only supported on hostssl connections"),
                 errcontext("line %d of configuration file \"%s\"",
                            line_num, file_name)));
        *err_msg = "cert authentication is only supported on hostssl connections";
        return NULL;
    }
 
    /*
     * For GSS and SSPI, set the default value of include_realm to true.
     * Having include_realm set to false is dangerous in multi-realm
     * situations and is generally considered bad practice.  We keep the
     * capability around for backwards compatibility, but we might want to
     * remove it at some point in the future.  Users who still need to strip
     * the realm off would be better served by using an appropriate regex in a
     * pg_ident.conf mapping.
     */
    if (parsedline->auth_method == uaGSS ||
        parsedline->auth_method == uaSSPI)
        parsedline->include_realm = true;
 
    /*
     * For SSPI, include_realm defaults to the SAM-compatible domain (aka
     * NetBIOS name) and user names instead of the Kerberos principal name for
     * compatibility.
     */
    if (parsedline->auth_method == uaSSPI)
    {
        parsedline->compat_realm = true;
        parsedline->upn_username = false;
    }
 
    /* Parse remaining arguments */
    while ((field = lnext(tok_line->fields, field)) != NULL)
    {
        tokens = lfirst(field);
        foreach(tokencell, tokens)
        {
            char       *val;
 
            token = lfirst(tokencell);
 
            str = pstrdup(token->string);
            val = strchr(str, '=');
            if (val == NULL)
            {
                /*
                 * Got something that's not a name=value pair.
                 */
                ereport(elevel,
                        (errcode(ERRCODE_CONFIG_FILE_ERROR),
                         errmsg("authentication option not in name=value format: %s", token->string),
                         errcontext("line %d of configuration file \"%s\"",
                                    line_num, file_name)));
                *err_msg = psprintf("authentication option not in name=value format: %s",
                                    token->string);
                return NULL;
            }
 
            *val++ = '\0';      /* str now holds "name", val holds "value" */
            if (!parse_hba_auth_opt(str, val, parsedline, elevel, err_msg))
                /* parse_hba_auth_opt already logged the error message */
                return NULL;
            pfree(str);
        }
    }
 
    /*
     * Check if the selected authentication method has any mandatory arguments
     * that are not set.
     */
    if (parsedline->auth_method == uaLDAP)
    {
#ifndef HAVE_LDAP_INITIALIZE
        /* Not mandatory for OpenLDAP, because it can use DNS SRV records */
        MANDATORY_AUTH_ARG(parsedline->ldapserver, "ldapserver", "ldap");
#endif
 
        /*
         * LDAP can operate in two modes: either with a direct bind, using
         * ldapprefix and ldapsuffix, or using a search+bind, using
         * ldapbasedn, ldapbinddn, ldapbindpasswd and one of
         * ldapsearchattribute or ldapsearchfilter.  Disallow mixing these
         * parameters.
         */
        if (parsedline->ldapprefix || parsedline->ldapsuffix)
        {
            if (parsedline->ldapbasedn ||
                parsedline->ldapbinddn ||
                parsedline->ldapbindpasswd ||
                parsedline->ldapsearchattribute ||
                parsedline->ldapsearchfilter)
            {
                ereport(elevel,
                        (errcode(ERRCODE_CONFIG_FILE_ERROR),
                         errmsg("cannot mix options for simple bind and search+bind modes"),
                         errcontext("line %d of configuration file \"%s\"",
                                    line_num, file_name)));
                *err_msg = "cannot mix options for simple bind and search+bind modes";
                return NULL;
            }
        }
        else if (!parsedline->ldapbasedn)
        {
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("authentication method \"ldap\" requires argument \"ldapbasedn\", \"ldapprefix\", or \"ldapsuffix\" to be set"),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, file_name)));
            *err_msg = "authentication method \"ldap\" requires argument \"ldapbasedn\", \"ldapprefix\", or \"ldapsuffix\" to be set";
            return NULL;
        }
 
        /*
         * When using search+bind, you can either use a simple attribute
         * (defaulting to "uid") or a fully custom search filter.  You can't
         * do both.
         */
        if (parsedline->ldapsearchattribute && parsedline->ldapsearchfilter)
        {
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("cannot use ldapsearchattribute together with ldapsearchfilter"),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, file_name)));
            *err_msg = "cannot use ldapsearchattribute together with ldapsearchfilter";
            return NULL;
        }
    }
 
    if (parsedline->auth_method == uaRADIUS)
    {
        MANDATORY_AUTH_ARG(parsedline->radiusservers, "radiusservers", "radius");
        MANDATORY_AUTH_ARG(parsedline->radiussecrets, "radiussecrets", "radius");
 
        if (parsedline->radiusservers == NIL)
        {
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("list of RADIUS servers cannot be empty"),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, file_name)));
            *err_msg = "list of RADIUS servers cannot be empty";
            return NULL;
        }
 
        if (parsedline->radiussecrets == NIL)
        {
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("list of RADIUS secrets cannot be empty"),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, file_name)));
            *err_msg = "list of RADIUS secrets cannot be empty";
            return NULL;
        }
 
        /*
         * Verify length of option lists - each can be 0 (except for secrets,
         * but that's already checked above), 1 (use the same value
         * everywhere) or the same as the number of servers.
         */
        if (!(list_length(parsedline->radiussecrets) == 1 ||
              list_length(parsedline->radiussecrets) == list_length(parsedline->radiusservers)))
        {
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("the number of RADIUS secrets (%d) must be 1 or the same as the number of RADIUS servers (%d)",
                            list_length(parsedline->radiussecrets),
                            list_length(parsedline->radiusservers)),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, file_name)));
            *err_msg = psprintf("the number of RADIUS secrets (%d) must be 1 or the same as the number of RADIUS servers (%d)",
                                list_length(parsedline->radiussecrets),
                                list_length(parsedline->radiusservers));
            return NULL;
        }
        if (!(list_length(parsedline->radiusports) == 0 ||
              list_length(parsedline->radiusports) == 1 ||
              list_length(parsedline->radiusports) == list_length(parsedline->radiusservers)))
        {
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("the number of RADIUS ports (%d) must be 1 or the same as the number of RADIUS servers (%d)",
                            list_length(parsedline->radiusports),
                            list_length(parsedline->radiusservers)),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, file_name)));
            *err_msg = psprintf("the number of RADIUS ports (%d) must be 1 or the same as the number of RADIUS servers (%d)",
                                list_length(parsedline->radiusports),
                                list_length(parsedline->radiusservers));
            return NULL;
        }
        if (!(list_length(parsedline->radiusidentifiers) == 0 ||
              list_length(parsedline->radiusidentifiers) == 1 ||
              list_length(parsedline->radiusidentifiers) == list_length(parsedline->radiusservers)))
        {
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("the number of RADIUS identifiers (%d) must be 1 or the same as the number of RADIUS servers (%d)",
                            list_length(parsedline->radiusidentifiers),
                            list_length(parsedline->radiusservers)),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, file_name)));
            *err_msg = psprintf("the number of RADIUS identifiers (%d) must be 1 or the same as the number of RADIUS servers (%d)",
                                list_length(parsedline->radiusidentifiers),
                                list_length(parsedline->radiusservers));
            return NULL;
        }
    }
 
    /*
     * Enforce any parameters implied by other settings.
     */
    if (parsedline->auth_method == uaCert)
    {
        /*
         * For auth method cert, client certificate validation is mandatory,
         * and it implies the level of verify-full.
         */
        parsedline->clientcert = clientCertFull;
    }
 
    /*
     * Enforce proper configuration of OAuth authentication.
     */
    if (parsedline->auth_method == uaOAuth)
    {
        MANDATORY_AUTH_ARG(parsedline->oauth_scope, "scope", "oauth");
        MANDATORY_AUTH_ARG(parsedline->oauth_issuer, "issuer", "oauth");
 
        /* Ensure a validator library is set and permitted by the config. */
        if (!check_oauth_validator(parsedline, elevel, err_msg))
            return NULL;
 
        /*
         * Supplying a usermap combined with the option to skip usermapping is
         * nonsensical and indicates a configuration error.
         */
        if (parsedline->oauth_skip_usermap && parsedline->usermap != NULL)
        {
            ereport(elevel,
                    errcode(ERRCODE_CONFIG_FILE_ERROR),
            /* translator: strings are replaced with hba options */
                    errmsg("%s cannot be used in combination with %s",
                           "map", "delegate_ident_mapping"),
                    errcontext("line %d of configuration file \"%s\"",
                               line_num, file_name));
            *err_msg = "map cannot be used in combination with delegate_ident_mapping";
            return NULL;
        }
    }
 
    return parsedline;
}
 
 
/*
 * Parse one name-value pair as an authentication option into the given
 * HbaLine.  Return true if we successfully parse the option, false if we
 * encounter an error.  In the event of an error, also log a message at
 * ereport level elevel, and store a message string into *err_msg.
 */
static bool
parse_hba_auth_opt(char *name, char *val, HbaLine *hbaline,
                   int elevel, char **err_msg)
{
    int         line_num = hbaline->linenumber;
    char       *file_name = hbaline->sourcefile;
 
#ifdef USE_LDAP
    hbaline->ldapscope = LDAP_SCOPE_SUBTREE;
#endif
 
    if (strcmp(name, "map") == 0)
    {
        if (hbaline->auth_method != uaIdent &&
            hbaline->auth_method != uaPeer &&
            hbaline->auth_method != uaGSS &&
            hbaline->auth_method != uaSSPI &&
            hbaline->auth_method != uaCert &&
            hbaline->auth_method != uaOAuth)
            INVALID_AUTH_OPTION("map", gettext_noop("ident, peer, gssapi, sspi, cert, and oauth"));
        hbaline->usermap = pstrdup(val);
    }
    else if (strcmp(name, "clientcert") == 0)
    {
        if (hbaline->conntype != ctHostSSL)
        {
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("clientcert can only be configured for \"hostssl\" rows"),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, file_name)));
            *err_msg = "clientcert can only be configured for \"hostssl\" rows";
            return false;
        }
 
        if (strcmp(val, "verify-full") == 0)
        {
            hbaline->clientcert = clientCertFull;
        }
        else if (strcmp(val, "verify-ca") == 0)
        {
            if (hbaline->auth_method == uaCert)
            {
                ereport(elevel,
                        (errcode(ERRCODE_CONFIG_FILE_ERROR),
                         errmsg("clientcert only accepts \"verify-full\" when using \"cert\" authentication"),
                         errcontext("line %d of configuration file \"%s\"",
                                    line_num, file_name)));
                *err_msg = "clientcert can only be set to \"verify-full\" when using \"cert\" authentication";
                return false;
            }
 
            hbaline->clientcert = clientCertCA;
        }
        else
        {
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("invalid value for clientcert: \"%s\"", val),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, file_name)));
            return false;
        }
    }
    else if (strcmp(name, "clientname") == 0)
    {
        if (hbaline->conntype != ctHostSSL)
        {
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("clientname can only be configured for \"hostssl\" rows"),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, file_name)));
            *err_msg = "clientname can only be configured for \"hostssl\" rows";
            return false;
        }
 
        if (strcmp(val, "CN") == 0)
        {
            hbaline->clientcertname = clientCertCN;
        }
        else if (strcmp(val, "DN") == 0)
        {
            hbaline->clientcertname = clientCertDN;
        }
        else
        {
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("invalid value for clientname: \"%s\"", val),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, file_name)));
            return false;
        }
    }
    else if (strcmp(name, "pamservice") == 0)
    {
        REQUIRE_AUTH_OPTION(uaPAM, "pamservice", "pam");
        hbaline->pamservice = pstrdup(val);
    }
    else if (strcmp(name, "pam_use_hostname") == 0)
    {
        REQUIRE_AUTH_OPTION(uaPAM, "pam_use_hostname", "pam");
        if (strcmp(val, "1") == 0)
            hbaline->pam_use_hostname = true;
        else
            hbaline->pam_use_hostname = false;
    }
    else if (strcmp(name, "ldapurl") == 0)
    {
#ifdef LDAP_API_FEATURE_X_OPENLDAP
        LDAPURLDesc *urldata;
        int         rc;
#endif
 
        REQUIRE_AUTH_OPTION(uaLDAP, "ldapurl", "ldap");
#ifdef LDAP_API_FEATURE_X_OPENLDAP
        rc = ldap_url_parse(val, &urldata);
        if (rc != LDAP_SUCCESS)
        {
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("could not parse LDAP URL \"%s\": %s", val, ldap_err2string(rc))));
            *err_msg = psprintf("could not parse LDAP URL \"%s\": %s",
                                val, ldap_err2string(rc));
            return false;
        }
 
        if (strcmp(urldata->lud_scheme, "ldap") != 0 &&
            strcmp(urldata->lud_scheme, "ldaps") != 0)
        {
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("unsupported LDAP URL scheme: %s", urldata->lud_scheme)));
            *err_msg = psprintf("unsupported LDAP URL scheme: %s",
                                urldata->lud_scheme);
            ldap_free_urldesc(urldata);
            return false;
        }
 
        if (urldata->lud_scheme)
            hbaline->ldapscheme = pstrdup(urldata->lud_scheme);
        if (urldata->lud_host)
            hbaline->ldapserver = pstrdup(urldata->lud_host);
        hbaline->ldapport = urldata->lud_port;
        if (urldata->lud_dn)
            hbaline->ldapbasedn = pstrdup(urldata->lud_dn);
 
        if (urldata->lud_attrs)
            hbaline->ldapsearchattribute = pstrdup(urldata->lud_attrs[0]);  /* only use first one */
        hbaline->ldapscope = urldata->lud_scope;
        if (urldata->lud_filter)
            hbaline->ldapsearchfilter = pstrdup(urldata->lud_filter);
        ldap_free_urldesc(urldata);
#else                           /* not OpenLDAP */
        ereport(elevel,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("LDAP URLs not supported on this platform")));
        *err_msg = "LDAP URLs not supported on this platform";
#endif                          /* not OpenLDAP */
    }
    else if (strcmp(name, "ldaptls") == 0)
    {
        REQUIRE_AUTH_OPTION(uaLDAP, "ldaptls", "ldap");
        if (strcmp(val, "1") == 0)
            hbaline->ldaptls = true;
        else
            hbaline->ldaptls = false;
    }
    else if (strcmp(name, "ldapscheme") == 0)
    {
        REQUIRE_AUTH_OPTION(uaLDAP, "ldapscheme", "ldap");
        if (strcmp(val, "ldap") != 0 && strcmp(val, "ldaps") != 0)
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("invalid ldapscheme value: \"%s\"", val),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, file_name)));
        hbaline->ldapscheme = pstrdup(val);
    }
    else if (strcmp(name, "ldapserver") == 0)
    {
        REQUIRE_AUTH_OPTION(uaLDAP, "ldapserver", "ldap");
        hbaline->ldapserver = pstrdup(val);
    }
    else if (strcmp(name, "ldapport") == 0)
    {
        REQUIRE_AUTH_OPTION(uaLDAP, "ldapport", "ldap");
        hbaline->ldapport = atoi(val);
        if (hbaline->ldapport == 0)
        {
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("invalid LDAP port number: \"%s\"", val),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, file_name)));
            *err_msg = psprintf("invalid LDAP port number: \"%s\"", val);
            return false;
        }
    }
    else if (strcmp(name, "ldapbinddn") == 0)
    {
        REQUIRE_AUTH_OPTION(uaLDAP, "ldapbinddn", "ldap");
        hbaline->ldapbinddn = pstrdup(val);
    }
    else if (strcmp(name, "ldapbindpasswd") == 0)
    {
        REQUIRE_AUTH_OPTION(uaLDAP, "ldapbindpasswd", "ldap");
        hbaline->ldapbindpasswd = pstrdup(val);
    }
    else if (strcmp(name, "ldapsearchattribute") == 0)
    {
        REQUIRE_AUTH_OPTION(uaLDAP, "ldapsearchattribute", "ldap");
        hbaline->ldapsearchattribute = pstrdup(val);
    }
    else if (strcmp(name, "ldapsearchfilter") == 0)
    {
        REQUIRE_AUTH_OPTION(uaLDAP, "ldapsearchfilter", "ldap");
        hbaline->ldapsearchfilter = pstrdup(val);
    }
    else if (strcmp(name, "ldapbasedn") == 0)
    {
        REQUIRE_AUTH_OPTION(uaLDAP, "ldapbasedn", "ldap");
        hbaline->ldapbasedn = pstrdup(val);
    }
    else if (strcmp(name, "ldapprefix") == 0)
    {
        REQUIRE_AUTH_OPTION(uaLDAP, "ldapprefix", "ldap");
        hbaline->ldapprefix = pstrdup(val);
    }
    else if (strcmp(name, "ldapsuffix") == 0)
    {
        REQUIRE_AUTH_OPTION(uaLDAP, "ldapsuffix", "ldap");
        hbaline->ldapsuffix = pstrdup(val);
    }
    else if (strcmp(name, "krb_realm") == 0)
    {
        if (hbaline->auth_method != uaGSS &&
            hbaline->auth_method != uaSSPI)
            INVALID_AUTH_OPTION("krb_realm", gettext_noop("gssapi and sspi"));
        hbaline->krb_realm = pstrdup(val);
    }
    else if (strcmp(name, "include_realm") == 0)
    {
        if (hbaline->auth_method != uaGSS &&
            hbaline->auth_method != uaSSPI)
            INVALID_AUTH_OPTION("include_realm", gettext_noop("gssapi and sspi"));
        if (strcmp(val, "1") == 0)
            hbaline->include_realm = true;
        else
            hbaline->include_realm = false;
    }
    else if (strcmp(name, "compat_realm") == 0)
    {
        if (hbaline->auth_method != uaSSPI)
            INVALID_AUTH_OPTION("compat_realm", gettext_noop("sspi"));
        if (strcmp(val, "1") == 0)
            hbaline->compat_realm = true;
        else
            hbaline->compat_realm = false;
    }
    else if (strcmp(name, "upn_username") == 0)
    {
        if (hbaline->auth_method != uaSSPI)
            INVALID_AUTH_OPTION("upn_username", gettext_noop("sspi"));
        if (strcmp(val, "1") == 0)
            hbaline->upn_username = true;
        else
            hbaline->upn_username = false;
    }
    else if (strcmp(name, "radiusservers") == 0)
    {
        struct addrinfo *gai_result;
        struct addrinfo hints;
        int         ret;
        List       *parsed_servers;
        ListCell   *l;
        char       *dupval = pstrdup(val);
 
        REQUIRE_AUTH_OPTION(uaRADIUS, "radiusservers", "radius");
 
        if (!SplitGUCList(dupval, ',', &parsed_servers))
        {
            /* syntax error in list */
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("could not parse RADIUS server list \"%s\"",
                            val),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, file_name)));
            return false;
        }
 
        /* For each entry in the list, translate it */
        foreach(l, parsed_servers)
        {
            MemSet(&hints, 0, sizeof(hints));
            hints.ai_socktype = SOCK_DGRAM;
            hints.ai_family = AF_UNSPEC;
 
            ret = pg_getaddrinfo_all((char *) lfirst(l), NULL, &hints, &gai_result);
            if (ret || !gai_result)
            {
                ereport(elevel,
                        (errcode(ERRCODE_CONFIG_FILE_ERROR),
                         errmsg("could not translate RADIUS server name \"%s\" to address: %s",
                                (char *) lfirst(l), gai_strerror(ret)),
                         errcontext("line %d of configuration file \"%s\"",
                                    line_num, file_name)));
                if (gai_result)
                    pg_freeaddrinfo_all(hints.ai_family, gai_result);
 
                list_free(parsed_servers);
                return false;
            }
            pg_freeaddrinfo_all(hints.ai_family, gai_result);
        }
 
        /* All entries are OK, so store them */
        hbaline->radiusservers = parsed_servers;
        hbaline->radiusservers_s = pstrdup(val);
    }
    else if (strcmp(name, "radiusports") == 0)
    {
        List       *parsed_ports;
        ListCell   *l;
        char       *dupval = pstrdup(val);
 
        REQUIRE_AUTH_OPTION(uaRADIUS, "radiusports", "radius");
 
        if (!SplitGUCList(dupval, ',', &parsed_ports))
        {
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("could not parse RADIUS port list \"%s\"",
                            val),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, file_name)));
            *err_msg = psprintf("invalid RADIUS port number: \"%s\"", val);
            return false;
        }
 
        foreach(l, parsed_ports)
        {
            if (atoi(lfirst(l)) == 0)
            {
                ereport(elevel,
                        (errcode(ERRCODE_CONFIG_FILE_ERROR),
                         errmsg("invalid RADIUS port number: \"%s\"", val),
                         errcontext("line %d of configuration file \"%s\"",
                                    line_num, file_name)));
 
                return false;
            }
        }
        hbaline->radiusports = parsed_ports;
        hbaline->radiusports_s = pstrdup(val);
    }
    else if (strcmp(name, "radiussecrets") == 0)
    {
        List       *parsed_secrets;
        char       *dupval = pstrdup(val);
 
        REQUIRE_AUTH_OPTION(uaRADIUS, "radiussecrets", "radius");
 
        if (!SplitGUCList(dupval, ',', &parsed_secrets))
        {
            /* syntax error in list */
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("could not parse RADIUS secret list \"%s\"",
                            val),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, file_name)));
            return false;
        }
 
        hbaline->radiussecrets = parsed_secrets;
        hbaline->radiussecrets_s = pstrdup(val);
    }
    else if (strcmp(name, "radiusidentifiers") == 0)
    {
        List       *parsed_identifiers;
        char       *dupval = pstrdup(val);
 
        REQUIRE_AUTH_OPTION(uaRADIUS, "radiusidentifiers", "radius");
 
        if (!SplitGUCList(dupval, ',', &parsed_identifiers))
        {
            /* syntax error in list */
            ereport(elevel,
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("could not parse RADIUS identifiers list \"%s\"",
                            val),
                     errcontext("line %d of configuration file \"%s\"",
                                line_num, file_name)));
            return false;
        }
 
        hbaline->radiusidentifiers = parsed_identifiers;
        hbaline->radiusidentifiers_s = pstrdup(val);
    }
    else if (strcmp(name, "issuer") == 0)
    {
        REQUIRE_AUTH_OPTION(uaOAuth, "issuer", "oauth");
        hbaline->oauth_issuer = pstrdup(val);
    }
    else if (strcmp(name, "scope") == 0)
    {
        REQUIRE_AUTH_OPTION(uaOAuth, "scope", "oauth");
        hbaline->oauth_scope = pstrdup(val);
    }
    else if (strcmp(name, "validator") == 0)
    {
        REQUIRE_AUTH_OPTION(uaOAuth, "validator", "oauth");
        hbaline->oauth_validator = pstrdup(val);
    }
    else if (strcmp(name, "delegate_ident_mapping") == 0)
    {
        REQUIRE_AUTH_OPTION(uaOAuth, "delegate_ident_mapping", "oauth");
        if (strcmp(val, "1") == 0)
            hbaline->oauth_skip_usermap = true;
        else
            hbaline->oauth_skip_usermap = false;
    }
    else
    {
        ereport(elevel,
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("unrecognized authentication option name: \"%s\"",
                        name),
                 errcontext("line %d of configuration file \"%s\"",
                            line_num, file_name)));
        *err_msg = psprintf("unrecognized authentication option name: \"%s\"",
                            name);
        return false;
    }
    return true;
}
 
/*
 *  Scan the pre-parsed hba file, looking for a match to the port's connection
 *  request.
 */
static void
check_hba(Port *port)
{
    Oid         roleid;
    ListCell   *line;
    HbaLine    *hba;
 
    /* Get the target role's OID.  Note we do not error out for bad role. */
    roleid = get_role_oid(port->user_name, true);
 
    foreach(line, parsed_hba_lines)
    {
        hba = (HbaLine *) lfirst(line);
 
        /* Check connection type */
        if (hba->conntype == ctLocal)
        {
            if (port->raddr.addr.ss_family != AF_UNIX)
                continue;
        }
        else
        {
            if (port->raddr.addr.ss_family == AF_UNIX)
                continue;
 
            /* Check SSL state */
            if (port->ssl_in_use)
            {
                /* Connection is SSL, match both "host" and "hostssl" */
                if (hba->conntype == ctHostNoSSL)
                    continue;
            }
            else
            {
                /* Connection is not SSL, match both "host" and "hostnossl" */
                if (hba->conntype == ctHostSSL)
                    continue;
            }
 
            /* Check GSSAPI state */
#ifdef ENABLE_GSS
            if (port->gss && port->gss->enc &&
                hba->conntype == ctHostNoGSS)
                continue;
            else if (!(port->gss && port->gss->enc) &&
                     hba->conntype == ctHostGSS)
                continue;
#else
            if (hba->conntype == ctHostGSS)
                continue;
#endif
 
            /* Check IP address */
            switch (hba->ip_cmp_method)
            {
                case ipCmpMask:
                    if (hba->hostname)
                    {
                        if (!check_hostname(port,
                                            hba->hostname))
                            continue;
                    }
                    else
                    {
                        if (!check_ip(&port->raddr,
                                      (struct sockaddr *) &hba->addr,
                                      (struct sockaddr *) &hba->mask))
                            continue;
                    }
                    break;
                case ipCmpAll:
                    break;
                case ipCmpSameHost:
                case ipCmpSameNet:
                    if (!check_same_host_or_net(&port->raddr,
                                                hba->ip_cmp_method))
                        continue;
                    break;
                default:
                    /* shouldn't get here, but deem it no-match if so */
                    continue;
            }
        }                       /* != ctLocal */
 
        /* Check database and role */
        if (!check_db(port->database_name, port->user_name, roleid,
                      hba->databases))
            continue;
 
        if (!check_role(port->user_name, roleid, hba->roles, false))
            continue;
 
        /* Found a record that matched! */
        port->hba = hba;
        return;
    }
 
    /* If no matching entry was found, then implicitly reject. */
    hba = palloc0_object(HbaLine);
    hba->auth_method = uaImplicitReject;
    port->hba = hba;
}
 
/*
 * Read the config file and create a List of HbaLine records for the contents.
 *
 * The configuration is read into a temporary list, and if any parse error
 * occurs the old list is kept in place and false is returned.  Only if the
 * whole file parses OK is the list replaced, and the function returns true.
 *
 * On a false result, caller will take care of reporting a FATAL error in case
 * this is the initial startup.  If it happens on reload, we just keep running
 * with the old data.
 */
bool
load_hba(void)
{
    FILE       *file;
    List       *hba_lines = NIL;
    ListCell   *line;
    List       *new_parsed_lines = NIL;
    bool        ok = true;
    MemoryContext oldcxt;
    MemoryContext hbacxt;
 
    file = open_auth_file(HbaFileName, LOG, 0, NULL);
    if (file == NULL)
    {
        /* error already logged */
        return false;
    }
 
    tokenize_auth_file(HbaFileName, file, &hba_lines, LOG, 0);
 
    /* Now parse all the lines */
    Assert(PostmasterContext);
    hbacxt = AllocSetContextCreate(PostmasterContext,
                                   "hba parser context",
                                   ALLOCSET_SMALL_SIZES);
    oldcxt = MemoryContextSwitchTo(hbacxt);
    foreach(line, hba_lines)
    {
        TokenizedAuthLine *tok_line = (TokenizedAuthLine *) lfirst(line);
        HbaLine    *newline;
 
        /* don't parse lines that already have errors */
        if (tok_line->err_msg != NULL)
        {
            ok = false;
            continue;
        }
 
        if ((newline = parse_hba_line(tok_line, LOG)) == NULL)
        {
            /* Parse error; remember there's trouble */
            ok = false;
 
            /*
             * Keep parsing the rest of the file so we can report errors on
             * more than the first line.  Error has already been logged, no
             * need for more chatter here.
             */
            continue;
        }
 
        new_parsed_lines = lappend(new_parsed_lines, newline);
    }
 
    /*
     * A valid HBA file must have at least one entry; else there's no way to
     * connect to the postmaster.  But only complain about this if we didn't
     * already have parsing errors.
     */
    if (ok && new_parsed_lines == NIL)
    {
        ereport(LOG,
                (errcode(ERRCODE_CONFIG_FILE_ERROR),
                 errmsg("configuration file \"%s\" contains no entries",
                        HbaFileName)));
        ok = false;
    }
 
    /* Free tokenizer memory */
    free_auth_file(file, 0);
    MemoryContextSwitchTo(oldcxt);
 
    if (!ok)
    {
        /*
         * File contained one or more errors, so bail out. MemoryContextDelete
         * is enough to clean up everything, including regexes.
         */
        MemoryContextDelete(hbacxt);
        return false;
    }
 
    /* Loaded new file successfully, replace the one we use */
    if (parsed_hba_context != NULL)
        MemoryContextDelete(parsed_hba_context);
    parsed_hba_context = hbacxt;
    parsed_hba_lines = new_parsed_lines;
 
    return true;
}
 
 
/*
 * Parse one tokenised line from the ident config file and store the result in
 * an IdentLine structure.
 *
 * If parsing fails, log a message at ereport level elevel, store an error
 * string in tok_line->err_msg and return NULL.
 *
 * If ident_user is a regular expression (ie. begins with a slash), it is
 * compiled and stored in IdentLine structure.
 *
 * Note: this function leaks memory when an error occurs.  Caller is expected
 * to have set a memory context that will be reset if this function returns
 * NULL.
 */
IdentLine *
parse_ident_line(TokenizedAuthLine *tok_line, int elevel)
{
    int         line_num = tok_line->line_num;
    char       *file_name = tok_line->file_name;
    char      **err_msg = &tok_line->err_msg;
    ListCell   *field;
    List       *tokens;
    AuthToken  *token;
    IdentLine  *parsedline;
 
    Assert(tok_line->fields != NIL);
    field = list_head(tok_line->fields);
 
    parsedline = palloc0_object(IdentLine);
    parsedline->linenumber = line_num;
 
    /* Get the map token (must exist) */
    tokens = lfirst(field);
    IDENT_MULTI_VALUE(tokens);
    token = linitial(tokens);
    parsedline->usermap = pstrdup(token->string);
 
    /* Get the ident user token */
    field = lnext(tok_line->fields, field);
    IDENT_FIELD_ABSENT(field);
    tokens = lfirst(field);
    IDENT_MULTI_VALUE(tokens);
    token = linitial(tokens);
 
    /* Copy the ident user token */
    parsedline->system_user = copy_auth_token(token);
 
    /* Get the PG rolename token */
    field = lnext(tok_line->fields, field);
    IDENT_FIELD_ABSENT(field);
    tokens = lfirst(field);
    IDENT_MULTI_VALUE(tokens);
    token = linitial(tokens);
    parsedline->pg_user = copy_auth_token(token);
 
    /*
     * Now that the field validation is done, compile a regex from the user
     * tokens, if necessary.
     */
    if (regcomp_auth_token(parsedline->system_user, file_name, line_num,
                           err_msg, elevel))
    {
        /* err_msg includes the error to report */
        return NULL;
    }
 
    if (regcomp_auth_token(parsedline->pg_user, file_name, line_num,
                           err_msg, elevel))
    {
        /* err_msg includes the error to report */
        return NULL;
    }
 
    return parsedline;
}
 
/*
 *  Process one line from the parsed ident config lines.
 *
 *  Compare input parsed ident line to the needed map, pg_user and system_user.
 *  *found_p and *error_p are set according to our results.
 */
static void
check_ident_usermap(IdentLine *identLine, const char *usermap_name,
                    const char *pg_user, const char *system_user,
                    bool case_insensitive, bool *found_p, bool *error_p)
{
    Oid         roleid;
 
    *found_p = false;
    *error_p = false;
 
    if (strcmp(identLine->usermap, usermap_name) != 0)
        /* Line does not match the map name we're looking for, so just abort */
        return;
 
    /* Get the target role's OID.  Note we do not error out for bad role. */
    roleid = get_role_oid(pg_user, true);
 
    /* Match? */
    if (token_has_regexp(identLine->system_user))
    {
        /*
         * Process the system username as a regular expression that returns
         * exactly one match. This is replaced for \1 in the database username
         * string, if present.
         */
        int         r;
        regmatch_t  matches[2];
        char       *ofs;
        AuthToken  *expanded_pg_user_token;
        bool        created_temporary_token = false;
 
        r = regexec_auth_token(system_user, identLine->system_user, 2, matches);
        if (r)
        {
            char        errstr[100];
 
            if (r != REG_NOMATCH)
            {
                /* REG_NOMATCH is not an error, everything else is */
                pg_regerror(r, identLine->system_user->regex, errstr, sizeof(errstr));
                ereport(LOG,
                        (errcode(ERRCODE_INVALID_REGULAR_EXPRESSION),
                         errmsg("regular expression match for \"%s\" failed: %s",
                                identLine->system_user->string + 1, errstr)));
                *error_p = true;
            }
            return;
        }
 
        /*
         * Replace \1 with the first captured group unless the field already
         * has some special meaning, like a group membership or a regexp-based
         * check.
         */
        if (!token_is_member_check(identLine->pg_user) &&
            !token_has_regexp(identLine->pg_user) &&
            (ofs = strstr(identLine->pg_user->string, "\\1")) != NULL)
        {
            const char *repl_str;
            size_t      repl_len;
            char       *old_pg_user;
            char       *expanded_pg_user;
            size_t      offset;
 
            /* substitution of the first argument requested */
            if (matches[1].rm_so < 0)
            {
                ereport(LOG,
                        (errcode(ERRCODE_INVALID_REGULAR_EXPRESSION),
                         errmsg("regular expression \"%s\" has no subexpressions as requested by backreference in \"%s\"",
                                identLine->system_user->string + 1, identLine->pg_user->string)));
                *error_p = true;
                return;
            }
            repl_str = system_user + matches[1].rm_so;
            repl_len = matches[1].rm_eo - matches[1].rm_so;
 
            /*
             * It's allowed to have more than one \1 in the string, and we'll
             * replace them all.  But that's pretty unusual so we optimize on
             * the assumption of only one occurrence, which motivates doing
             * repeated replacements instead of making two passes over the
             * string to determine the final length right away.
             */
            old_pg_user = identLine->pg_user->string;
            do
            {
                /*
                 * length: current length minus length of \1 plus length of
                 * replacement plus null terminator
                 */
                expanded_pg_user = palloc(strlen(old_pg_user) - 2 + repl_len + 1);
                /* ofs points into the old_pg_user string at this point */
                offset = ofs - old_pg_user;
                memcpy(expanded_pg_user, old_pg_user, offset);
                memcpy(expanded_pg_user + offset, repl_str, repl_len);
                strcpy(expanded_pg_user + offset + repl_len, ofs + 2);
                if (old_pg_user != identLine->pg_user->string)
                    pfree(old_pg_user);
                old_pg_user = expanded_pg_user;
            } while ((ofs = strstr(old_pg_user + offset + repl_len, "\\1")) != NULL);
 
            /*
             * Mark the token as quoted, so it will only be compared literally
             * and not for some special meaning, such as "all" or a group
             * membership check.
             */
            expanded_pg_user_token = make_auth_token(expanded_pg_user, true);
            created_temporary_token = true;
            pfree(expanded_pg_user);
        }
        else
        {
            expanded_pg_user_token = identLine->pg_user;
        }
 
        /* check the Postgres user */
        *found_p = check_role(pg_user, roleid,
                              list_make1(expanded_pg_user_token),
                              case_insensitive);
 
        if (created_temporary_token)
            free_auth_token(expanded_pg_user_token);
 
        return;
    }
    else
    {
        /*
         * Not a regular expression, so make a complete match.  If the system
         * user does not match, just leave.
         */
        if (case_insensitive)
        {
            if (!token_matches_insensitive(identLine->system_user,
                                           system_user))
                return;
        }
        else
        {
            if (!token_matches(identLine->system_user, system_user))
                return;
        }
 
        /* check the Postgres user */
        *found_p = check_role(pg_user, roleid,
                              list_make1(identLine->pg_user),
                              case_insensitive);
    }
}
 
 
/*
 *  Scan the (pre-parsed) ident usermap file line by line, looking for a match
 *
 *  See if the system user with ident username "system_user" is allowed to act as
 *  Postgres user "pg_user" according to usermap "usermap_name".
 *
 *  Special case: Usermap NULL, equivalent to what was previously called
 *  "sameuser" or "samerole", means don't look in the usermap file.
 *  That's an implied map wherein "pg_user" must be identical to
 *  "system_user" in order to be authorized.
 *
 *  Iff authorized, return STATUS_OK, otherwise return STATUS_ERROR.
 */
int
check_usermap(const char *usermap_name,
              const char *pg_user,
              const char *system_user,
              bool case_insensitive)
{
    bool        found_entry = false,
                error = false;
 
    if (usermap_name == NULL || usermap_name[0] == '\0')
    {
        if (case_insensitive)
        {
            if (pg_strcasecmp(pg_user, system_user) == 0)
                return STATUS_OK;
        }
        else
        {
            if (strcmp(pg_user, system_user) == 0)
                return STATUS_OK;
        }
        ereport(LOG,
                (errmsg("provided user name (%s) and authenticated user name (%s) do not match",
                        pg_user, system_user)));
        return STATUS_ERROR;
    }
    else
    {
        ListCell   *line_cell;
 
        foreach(line_cell, parsed_ident_lines)
        {
            check_ident_usermap(lfirst(line_cell), usermap_name,
                                pg_user, system_user, case_insensitive,
                                &found_entry, &error);
            if (found_entry || error)
                break;
        }
    }
    if (!found_entry && !error)
    {
        ereport(LOG,
                (errmsg("no match in usermap \"%s\" for user \"%s\" authenticated as \"%s\"",
                        usermap_name, pg_user, system_user)));
    }
    return found_entry ? STATUS_OK : STATUS_ERROR;
}
 
 
/*
 * Read the ident config file and create a List of IdentLine records for
 * the contents.
 *
 * This works the same as load_hba(), but for the user config file.
 */
bool
load_ident(void)
{
    FILE       *file;
    List       *ident_lines = NIL;
    ListCell   *line_cell;
    List       *new_parsed_lines = NIL;
    bool        ok = true;
    MemoryContext oldcxt;
    MemoryContext ident_context;
    IdentLine  *newline;
 
    /* not FATAL ... we just won't do any special ident maps */
    file = open_auth_file(IdentFileName, LOG, 0, NULL);
    if (file == NULL)
    {
        /* error already logged */
        return false;
    }
 
    tokenize_auth_file(IdentFileName, file, &ident_lines, LOG, 0);
 
    /* Now parse all the lines */
    Assert(PostmasterContext);
    ident_context = AllocSetContextCreate(PostmasterContext,
                                          "ident parser context",
                                          ALLOCSET_SMALL_SIZES);
    oldcxt = MemoryContextSwitchTo(ident_context);
    foreach(line_cell, ident_lines)
    {
        TokenizedAuthLine *tok_line = (TokenizedAuthLine *) lfirst(line_cell);
 
        /* don't parse lines that already have errors */
        if (tok_line->err_msg != NULL)
        {
            ok = false;
            continue;
        }
 
        if ((newline = parse_ident_line(tok_line, LOG)) == NULL)
        {
            /* Parse error; remember there's trouble */
            ok = false;
 
            /*
             * Keep parsing the rest of the file so we can report errors on
             * more than the first line.  Error has already been logged, no
             * need for more chatter here.
             */
            continue;
        }
 
        new_parsed_lines = lappend(new_parsed_lines, newline);
    }
 
    /* Free tokenizer memory */
    free_auth_file(file, 0);
    MemoryContextSwitchTo(oldcxt);
 
    if (!ok)
    {
        /*
         * File contained one or more errors, so bail out. MemoryContextDelete
         * is enough to clean up everything, including regexes.
         */
        MemoryContextDelete(ident_context);
        return false;
    }
 
    /* Loaded new file successfully, replace the one we use */
    if (parsed_ident_context != NULL)
        MemoryContextDelete(parsed_ident_context);
 
    parsed_ident_context = ident_context;
    parsed_ident_lines = new_parsed_lines;
 
    return true;
}
 
 
 
/*
 *  Determine what authentication method should be used when accessing database
 *  "database" from frontend "raddr", user "user".  Return the method and
 *  an optional argument (stored in fields of *port), and STATUS_OK.
 *
 *  If the file does not contain any entry matching the request, we return
 *  method = uaImplicitReject.
 */
void
hba_getauthmethod(Port *port)
{
    check_hba(port);
}
 
 
/*
 * Return the name of the auth method in use ("gss", "md5", "trust", etc.).
 *
 * The return value is statically allocated (see the UserAuthName array) and
 * should not be freed.
 */
const char *
hba_authname(UserAuth auth_method)
{
    return UserAuthName[auth_method];
}