elog.h

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/*-------------------------------------------------------------------------
 *
 * elog.h
 *    POSTGRES error reporting/logging definitions.
 *
 *
 * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/include/utils/elog.h
 *
 *-------------------------------------------------------------------------
 */
#ifndef ELOG_H
#define ELOG_H

#include <setjmp.h>

/* Error level codes */
#define DEBUG5      10          /* Debugging messages, in categories of
                                 * decreasing detail. */
#define DEBUG4      11
#define DEBUG3      12
#define DEBUG2      13
#define DEBUG1      14          /* used by GUC debug_* variables */
#define LOG         15          /* Server operational messages; sent only to
                                 * server log by default. */
#define LOG_SERVER_ONLY 16      /* Same as LOG for server reporting, but never
                                 * sent to client. */
#define COMMERROR   LOG_SERVER_ONLY /* Client communication problems; same as
                                     * LOG for server reporting, but never
                                     * sent to client. */
#define INFO        17          /* Messages specifically requested by user (eg
                                 * VACUUM VERBOSE output); always sent to
                                 * client regardless of client_min_messages,
                                 * but by default not sent to server log. */
#define NOTICE      18          /* Helpful messages to users about query
                                 * operation; sent to client and not to server
                                 * log by default. */
#define WARNING     19          /* Warnings.  NOTICE is for expected messages
                                 * like implicit sequence creation by SERIAL.
                                 * WARNING is for unexpected messages. */
#define PGWARNING   19          /* Must equal WARNING; see NOTE below. */
#define WARNING_CLIENT_ONLY 20  /* Warnings to be sent to client as usual, but
                                 * never to the server log. */
#define ERROR       21          /* user error - abort transaction; return to
                                 * known state */
#define PGERROR     21          /* Must equal ERROR; see NOTE below. */
#define FATAL       22          /* fatal error - abort process */
#define PANIC       23          /* take down the other backends with me */

/*
 * NOTE: the alternate names PGWARNING and PGERROR are useful for dealing
 * with third-party headers that make other definitions of WARNING and/or
 * ERROR.  One can, for example, re-define ERROR as PGERROR after including
 * such a header.
 */


/* macros for representing SQLSTATE strings compactly */
#define PGSIXBIT(ch)    (((ch) - '0') & 0x3F)
#define PGUNSIXBIT(val) (((val) & 0x3F) + '0')

#define MAKE_SQLSTATE(ch1,ch2,ch3,ch4,ch5)  \
    (PGSIXBIT(ch1) + (PGSIXBIT(ch2) << 6) + (PGSIXBIT(ch3) << 12) + \
     (PGSIXBIT(ch4) << 18) + (PGSIXBIT(ch5) << 24))

/* These macros depend on the fact that '0' becomes a zero in PGSIXBIT */
#define ERRCODE_TO_CATEGORY(ec)  ((ec) & ((1 << 12) - 1))
#define ERRCODE_IS_CATEGORY(ec)  (((ec) & ~((1 << 12) - 1)) == 0)

/* SQLSTATE codes for errors are defined in a separate file */
#include "utils/errcodes.h"

/*
 * Provide a way to prevent "errno" from being accidentally used inside an
 * elog() or ereport() invocation.  Since we know that some operating systems
 * define errno as something involving a function call, we'll put a local
 * variable of the same name as that function in the local scope to force a
 * compile error.  On platforms that don't define errno in that way, nothing
 * happens, so we get no warning ... but we can live with that as long as it
 * happens on some popular platforms.
 */
#if defined(errno) && defined(__linux__)
#define pg_prevent_errno_in_scope() int __errno_location pg_attribute_unused()
#elif defined(errno) && (defined(__darwin__) || defined(__freebsd__))
#define pg_prevent_errno_in_scope() int __error pg_attribute_unused()
#else
#define pg_prevent_errno_in_scope()
#endif


/*----------
 * New-style error reporting API: to be used in this way:
 *      ereport(ERROR,
 *              errcode(ERRCODE_UNDEFINED_CURSOR),
 *              errmsg("portal \"%s\" not found", stmt->portalname),
 *              ... other errxxx() fields as needed ...);
 *
 * The error level is required, and so is a primary error message (errmsg
 * or errmsg_internal).  All else is optional.  errcode() defaults to
 * ERRCODE_INTERNAL_ERROR if elevel is ERROR or more, ERRCODE_WARNING
 * if elevel is WARNING, or ERRCODE_SUCCESSFUL_COMPLETION if elevel is
 * NOTICE or below.
 *
 * Before Postgres v12, extra parentheses were required around the
 * list of auxiliary function calls; that's now optional.
 *
 * ereport_domain() allows a message domain to be specified, for modules that
 * wish to use a different message catalog from the backend's.  To avoid having
 * one copy of the default text domain per .o file, we define it as NULL here
 * and have errstart insert the default text domain.  Modules can either use
 * ereport_domain() directly, or preferably they can override the TEXTDOMAIN
 * macro.
 *
 * When __builtin_constant_p is available and elevel >= ERROR we make a call
 * to errstart_cold() instead of errstart().  This version of the function is
 * marked with pg_attribute_cold which will coax supporting compilers into
 * generating code which is more optimized towards non-ERROR cases.  Because
 * we use __builtin_constant_p() in the condition, when elevel is not a
 * compile-time constant, or if it is, but it's < ERROR, the compiler has no
 * need to generate any code for this branch.  It can simply call errstart()
 * unconditionally.
 *
 * If elevel >= ERROR, the call will not return; we try to inform the compiler
 * of that via pg_unreachable().  However, no useful optimization effect is
 * obtained unless the compiler sees elevel as a compile-time constant, else
 * we're just adding code bloat.  So, if __builtin_constant_p is available,
 * use that to cause the second if() to vanish completely for non-constant
 * cases.  We avoid using a local variable because it's not necessary and
 * prevents gcc from making the unreachability deduction at optlevel -O0.
 *----------
 */
#ifdef HAVE__BUILTIN_CONSTANT_P
#define ereport_domain(elevel, domain, ...) \
    do { \
        pg_prevent_errno_in_scope(); \
        if (__builtin_constant_p(elevel) && (elevel) >= ERROR ? \
            errstart_cold(elevel, domain) : \
            errstart(elevel, domain)) \
            __VA_ARGS__, errfinish(__FILE__, __LINE__, PG_FUNCNAME_MACRO); \
        if (__builtin_constant_p(elevel) && (elevel) >= ERROR) \
            pg_unreachable(); \
    } while(0)
#else                           /* !HAVE__BUILTIN_CONSTANT_P */
#define ereport_domain(elevel, domain, ...) \
    do { \
        const int elevel_ = (elevel); \
        pg_prevent_errno_in_scope(); \
        if (errstart(elevel_, domain)) \
            __VA_ARGS__, errfinish(__FILE__, __LINE__, PG_FUNCNAME_MACRO); \
        if (elevel_ >= ERROR) \
            pg_unreachable(); \
    } while(0)
#endif                          /* HAVE__BUILTIN_CONSTANT_P */

#define ereport(elevel, ...)    \
    ereport_domain(elevel, TEXTDOMAIN, __VA_ARGS__)

#define TEXTDOMAIN NULL

extern bool message_level_is_interesting(int elevel);

extern bool errstart(int elevel, const char *domain);
extern pg_attribute_cold bool errstart_cold(int elevel, const char *domain);
extern void errfinish(const char *filename, int lineno, const char *funcname);

extern int  errcode(int sqlerrcode);

extern int  errcode_for_file_access(void);
extern int  errcode_for_socket_access(void);

extern int  errmsg(const char *fmt,...) pg_attribute_printf(1, 2);
extern int  errmsg_internal(const char *fmt,...) pg_attribute_printf(1, 2);

extern int  errmsg_plural(const char *fmt_singular, const char *fmt_plural,
                          unsigned long n,...) pg_attribute_printf(1, 4) pg_attribute_printf(2, 4);

extern int  errdetail(const char *fmt,...) pg_attribute_printf(1, 2);
extern int  errdetail_internal(const char *fmt,...) pg_attribute_printf(1, 2);

extern int  errdetail_log(const char *fmt,...) pg_attribute_printf(1, 2);

extern int  errdetail_log_plural(const char *fmt_singular,
                                 const char *fmt_plural,
                                 unsigned long n,...) pg_attribute_printf(1, 4) pg_attribute_printf(2, 4);

extern int  errdetail_plural(const char *fmt_singular, const char *fmt_plural,
                             unsigned long n,...) pg_attribute_printf(1, 4) pg_attribute_printf(2, 4);

extern int  errhint(const char *fmt,...) pg_attribute_printf(1, 2);

extern int  errhint_plural(const char *fmt_singular, const char *fmt_plural,
                           unsigned long n,...) pg_attribute_printf(1, 4) pg_attribute_printf(2, 4);

/*
 * errcontext() is typically called in error context callback functions, not
 * within an ereport() invocation. The callback function can be in a different
 * module than the ereport() call, so the message domain passed in errstart()
 * is not usually the correct domain for translating the context message.
 * set_errcontext_domain() first sets the domain to be used, and
 * errcontext_msg() passes the actual message.
 */
#define errcontext  set_errcontext_domain(TEXTDOMAIN),  errcontext_msg

extern int  set_errcontext_domain(const char *domain);

extern int  errcontext_msg(const char *fmt,...) pg_attribute_printf(1, 2);

extern int  errhidestmt(bool hide_stmt);
extern int  errhidecontext(bool hide_ctx);

extern int  errbacktrace(void);

extern int  errposition(int cursorpos);

extern int  internalerrposition(int cursorpos);
extern int  internalerrquery(const char *query);

extern int  err_generic_string(int field, const char *str);

extern int  geterrcode(void);
extern int  geterrposition(void);
extern int  getinternalerrposition(void);


/*----------
 * Old-style error reporting API: to be used in this way:
 *      elog(ERROR, "portal \"%s\" not found", stmt->portalname);
 *----------
 */
#define elog(elevel, ...)  \
    ereport(elevel, errmsg_internal(__VA_ARGS__))


/* Support for constructing error strings separately from ereport() calls */

extern void pre_format_elog_string(int errnumber, const char *domain);
extern char *format_elog_string(const char *fmt,...) pg_attribute_printf(1, 2);


/* Support for attaching context information to error reports */

typedef struct ErrorContextCallback
{
    struct ErrorContextCallback *previous;
    void        (*callback) (void *arg);
    void       *arg;
} ErrorContextCallback;

extern PGDLLIMPORT ErrorContextCallback *error_context_stack;


/*----------
 * API for catching ereport(ERROR) exits.  Use these macros like so:
 *
 *      PG_TRY();
 *      {
 *          ... code that might throw ereport(ERROR) ...
 *      }
 *      PG_CATCH();
 *      {
 *          ... error recovery code ...
 *      }
 *      PG_END_TRY();
 *
 * (The braces are not actually necessary, but are recommended so that
 * pgindent will indent the construct nicely.)  The error recovery code
 * can either do PG_RE_THROW to propagate the error outwards, or do a
 * (sub)transaction abort. Failure to do so may leave the system in an
 * inconsistent state for further processing.
 *
 * For the common case that the error recovery code and the cleanup in the
 * normal code path are identical, the following can be used instead:
 *
 *      PG_TRY();
 *      {
 *          ... code that might throw ereport(ERROR) ...
 *      }
 *      PG_FINALLY();
 *      {
 *          ... cleanup code ...
 *      }
 *      PG_END_TRY();
 *
 * The cleanup code will be run in either case, and any error will be rethrown
 * afterwards.
 *
 * You cannot use both PG_CATCH() and PG_FINALLY() in the same
 * PG_TRY()/PG_END_TRY() block.
 *
 * Note: while the system will correctly propagate any new ereport(ERROR)
 * occurring in the recovery section, there is a small limit on the number
 * of levels this will work for.  It's best to keep the error recovery
 * section simple enough that it can't generate any new errors, at least
 * not before popping the error stack.
 *
 * Note: an ereport(FATAL) will not be caught by this construct; control will
 * exit straight through proc_exit().  Therefore, do NOT put any cleanup
 * of non-process-local resources into the error recovery section, at least
 * not without taking thought for what will happen during ereport(FATAL).
 * The PG_ENSURE_ERROR_CLEANUP macros provided by storage/ipc.h may be
 * helpful in such cases.
 *
 * Note: if a local variable of the function containing PG_TRY is modified
 * in the PG_TRY section and used in the PG_CATCH section, that variable
 * must be declared "volatile" for POSIX compliance.  This is not mere
 * pedantry; we have seen bugs from compilers improperly optimizing code
 * away when such a variable was not marked.  Beware that gcc's -Wclobbered
 * warnings are just about entirely useless for catching such oversights.
 *----------
 */
#define PG_TRY()  \
    do { \
        sigjmp_buf *_save_exception_stack = PG_exception_stack; \
        ErrorContextCallback *_save_context_stack = error_context_stack; \
        sigjmp_buf _local_sigjmp_buf; \
        bool _do_rethrow = false; \
        if (sigsetjmp(_local_sigjmp_buf, 0) == 0) \
        { \
            PG_exception_stack = &_local_sigjmp_buf

#define PG_CATCH()  \
        } \
        else \
        { \
            PG_exception_stack = _save_exception_stack; \
            error_context_stack = _save_context_stack

#define PG_FINALLY() \
        } \
        else \
            _do_rethrow = true; \
        { \
            PG_exception_stack = _save_exception_stack; \
            error_context_stack = _save_context_stack

#define PG_END_TRY()  \
        } \
        if (_do_rethrow) \
                PG_RE_THROW(); \
        PG_exception_stack = _save_exception_stack; \
        error_context_stack = _save_context_stack; \
    } while (0)

/*
 * Some compilers understand pg_attribute_noreturn(); for other compilers,
 * insert pg_unreachable() so that the compiler gets the point.
 */
#ifdef HAVE_PG_ATTRIBUTE_NORETURN
#define PG_RE_THROW()  \
    pg_re_throw()
#else
#define PG_RE_THROW()  \
    (pg_re_throw(), pg_unreachable())
#endif

extern PGDLLIMPORT sigjmp_buf *PG_exception_stack;


/* Stuff that error handlers might want to use */

/*
 * ErrorData holds the data accumulated during any one ereport() cycle.
 * Any non-NULL pointers must point to palloc'd data.
 * (The const pointers are an exception; we assume they point at non-freeable
 * constant strings.)
 */
typedef struct ErrorData
{
    int         elevel;         /* error level */
    bool        output_to_server;   /* will report to server log? */
    bool        output_to_client;   /* will report to client? */
    bool        hide_stmt;      /* true to prevent STATEMENT: inclusion */
    bool        hide_ctx;       /* true to prevent CONTEXT: inclusion */
    const char *filename;       /* __FILE__ of ereport() call */
    int         lineno;         /* __LINE__ of ereport() call */
    const char *funcname;       /* __func__ of ereport() call */
    const char *domain;         /* message domain */
    const char *context_domain; /* message domain for context message */
    int         sqlerrcode;     /* encoded ERRSTATE */
    char       *message;        /* primary error message (translated) */
    char       *detail;         /* detail error message */
    char       *detail_log;     /* detail error message for server log only */
    char       *hint;           /* hint message */
    char       *context;        /* context message */
    char       *backtrace;      /* backtrace */
    const char *message_id;     /* primary message's id (original string) */
    char       *schema_name;    /* name of schema */
    char       *table_name;     /* name of table */
    char       *column_name;    /* name of column */
    char       *datatype_name;  /* name of datatype */
    char       *constraint_name;    /* name of constraint */
    int         cursorpos;      /* cursor index into query string */
    int         internalpos;    /* cursor index into internalquery */
    char       *internalquery;  /* text of internally-generated query */
    int         saved_errno;    /* errno at entry */

    /* context containing associated non-constant strings */
    struct MemoryContextData *assoc_context;
} ErrorData;

extern void EmitErrorReport(void);
extern ErrorData *CopyErrorData(void);
extern void FreeErrorData(ErrorData *edata);
extern void FlushErrorState(void);
extern void ReThrowError(ErrorData *edata) pg_attribute_noreturn();
extern void ThrowErrorData(ErrorData *edata);
extern void pg_re_throw(void) pg_attribute_noreturn();

extern char *GetErrorContextStack(void);

/* Hook for intercepting messages before they are sent to the server log */
typedef void (*emit_log_hook_type) (ErrorData *edata);
extern PGDLLIMPORT emit_log_hook_type emit_log_hook;


/* GUC-configurable parameters */

typedef enum
{
    PGERROR_TERSE,              /* single-line error messages */
    PGERROR_DEFAULT,            /* recommended style */
    PGERROR_VERBOSE             /* all the facts, ma'am */
}           PGErrorVerbosity;

extern int  Log_error_verbosity;
extern char *Log_line_prefix;
extern int  Log_destination;
extern char *Log_destination_string;
extern bool syslog_sequence_numbers;
extern bool syslog_split_messages;

/* Log destination bitmap */
#define LOG_DESTINATION_STDERR   1
#define LOG_DESTINATION_SYSLOG   2
#define LOG_DESTINATION_EVENTLOG 4
#define LOG_DESTINATION_CSVLOG   8

/* Other exported functions */
extern void DebugFileOpen(void);
extern char *unpack_sql_state(int sql_state);
extern bool in_error_recursion_trouble(void);

#ifdef HAVE_SYSLOG
extern void set_syslog_parameters(const char *ident, int facility);
#endif

/*
 * Write errors to stderr (or by equal means when stderr is
 * not available). Used before ereport/elog can be used
 * safely (memory context, GUC load etc)
 */
extern void write_stderr(const char *fmt,...) pg_attribute_printf(1, 2);

#endif                          /* ELOG_H */