logging.c

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/*-------------------------------------------------------------------------
 * Logging framework for frontend programs
 *
 * Copyright (c) 2018-2026, PostgreSQL Global Development Group
 *
 * src/common/logging.c
 *
 *-------------------------------------------------------------------------
 */
 
#ifndef FRONTEND
#error "This file is not expected to be compiled for backend code"
#endif
 
#include "postgres_fe.h"
 
#include <unistd.h>
 
#include "common/logging.h"
 
enum pg_log_level __pg_log_level;
 
static const char *progname;
static int  log_flags;
 
static void (*log_pre_callback) (void);
static void (*log_locus_callback) (const char **, uint64 *);
 
static FILE *log_logfile;
 
static const char *sgr_error = NULL;
static const char *sgr_warning = NULL;
static const char *sgr_note = NULL;
static const char *sgr_locus = NULL;
 
#define SGR_ERROR_DEFAULT "01;31"
#define SGR_WARNING_DEFAULT "01;35"
#define SGR_NOTE_DEFAULT "01;36"
#define SGR_LOCUS_DEFAULT "01"
 
#define ANSI_ESCAPE_FMT "\x1b[%sm"
#define ANSI_ESCAPE_RESET "\x1b[0m"
 
#ifdef WIN32
 
#ifndef ENABLE_VIRTUAL_TERMINAL_PROCESSING
#define ENABLE_VIRTUAL_TERMINAL_PROCESSING 0x0004
#endif
 
/*
 * Attempt to enable VT100 sequence processing for colorization on Windows.
 * If current environment is not VT100-compatible or if this mode could not
 * be enabled, return false.
 */
static bool
enable_vt_processing(void)
{
    /* Check stderr */
    HANDLE      hOut = GetStdHandle(STD_ERROR_HANDLE);
    DWORD       dwMode = 0;
 
    if (hOut == INVALID_HANDLE_VALUE)
        return false;
 
    /*
     * Look for the current console settings and check if VT100 is already
     * enabled.
     */
    if (!GetConsoleMode(hOut, &dwMode))
        return false;
    if ((dwMode & ENABLE_VIRTUAL_TERMINAL_PROCESSING) != 0)
        return true;
 
    dwMode |= ENABLE_VIRTUAL_TERMINAL_PROCESSING;
    if (!SetConsoleMode(hOut, dwMode))
        return false;
    return true;
}
#endif                          /* WIN32 */
 
/*
 * This should be called before any output happens.
 */
void
pg_logging_init(const char *argv0)
{
    const char *pg_color_env = getenv("PG_COLOR");
    bool        log_color = false;
    bool        color_terminal = isatty(fileno(stderr));
 
#ifdef WIN32
 
    /*
     * On Windows, check if environment is VT100-compatible if using a
     * terminal.
     */
    if (color_terminal)
        color_terminal = enable_vt_processing();
#endif
 
    /* usually the default, but not on Windows */
    setvbuf(stderr, NULL, _IONBF, 0);
 
    progname = get_progname(argv0);
    __pg_log_level = PG_LOG_INFO;
 
    if (pg_color_env)
    {
        if (strcmp(pg_color_env, "always") == 0 ||
            (strcmp(pg_color_env, "auto") == 0 && color_terminal))
            log_color = true;
    }
 
    if (log_color)
    {
        const char *pg_colors_env = getenv("PG_COLORS");
 
        if (pg_colors_env)
        {
            char       *colors = strdup(pg_colors_env);
 
            if (colors)
            {
                char       *token;
                char       *cp = colors;
 
                while ((token = strsep(&cp, ":")))
                {
                    char       *e = strchr(token, '=');
 
                    if (e)
                    {
                        char       *name;
                        char       *value;
 
                        *e = '\0';
                        name = token;
                        value = e + 1;
 
                        if (strcmp(name, "error") == 0)
                            sgr_error = strdup(value);
                        if (strcmp(name, "warning") == 0)
                            sgr_warning = strdup(value);
                        if (strcmp(name, "note") == 0)
                            sgr_note = strdup(value);
                        if (strcmp(name, "locus") == 0)
                            sgr_locus = strdup(value);
                    }
                }
 
                free(colors);
            }
        }
        else
        {
            sgr_error = SGR_ERROR_DEFAULT;
            sgr_warning = SGR_WARNING_DEFAULT;
            sgr_note = SGR_NOTE_DEFAULT;
            sgr_locus = SGR_LOCUS_DEFAULT;
        }
    }
}
 
/*
 * Change the logging flags.
 */
void
pg_logging_config(int new_flags)
{
    log_flags = new_flags;
}
 
/*
 * pg_logging_init sets the default log level to INFO.  Programs that prefer
 * a different default should use this to set it, immediately afterward.
 */
void
pg_logging_set_level(enum pg_log_level new_level)
{
    __pg_log_level = new_level;
}
 
/*
 * Command line switches such as --verbose should invoke this.
 */
void
pg_logging_increase_verbosity(void)
{
    /*
     * The enum values are chosen such that we have to decrease __pg_log_level
     * in order to become more verbose.
     */
    if (__pg_log_level > PG_LOG_NOTSET + 1)
        __pg_log_level--;
}
 
void
pg_logging_set_pre_callback(void (*cb) (void))
{
    log_pre_callback = cb;
}
 
void
pg_logging_set_locus_callback(void (*cb) (const char **filename, uint64 *lineno))
{
    log_locus_callback = cb;
}
 
void
pg_logging_set_logfile(FILE *logfile)
{
    log_logfile = logfile;
}
 
void
pg_logging_unset_logfile(void)
{
    log_logfile = NULL;
}
 
void
pg_log_generic(enum pg_log_level level, enum pg_log_part part,
               const char *pg_restrict fmt,...)
{
    va_list     ap;
 
    va_start(ap, fmt);
    pg_log_generic_v(level, part, fmt, ap);
    va_end(ap);
}
 
void
pg_log_generic_v(enum pg_log_level level, enum pg_log_part part,
                 const char *pg_restrict fmt, va_list ap)
{
    int         save_errno = errno;
    const char *filename = NULL;
    uint64      lineno = 0;
    va_list     ap2;
    size_t      required_len;
    char       *buf;
 
    Assert(progname);
    Assert(level);
    Assert(fmt);
    Assert(fmt[strlen(fmt) - 1] != '\n');
 
    /* Do nothing if log level is too low. */
    if (level < __pg_log_level)
        return;
 
    /*
     * Flush stdout before output to stderr, to ensure sync even when stdout
     * is buffered.
     */
    fflush(stdout);
 
    if (log_pre_callback)
        log_pre_callback();
 
    if (log_locus_callback)
        log_locus_callback(&filename, &lineno);
 
    fmt = _(fmt);
 
    if (!(log_flags & PG_LOG_FLAG_TERSE) || filename)
    {
        if (sgr_locus)
            fprintf(stderr, ANSI_ESCAPE_FMT, sgr_locus);
        if (!(log_flags & PG_LOG_FLAG_TERSE))
            fprintf(stderr, "%s:", progname);
        if (filename)
        {
            fprintf(stderr, "%s:", filename);
            if (lineno > 0)
                fprintf(stderr, UINT64_FORMAT ":", lineno);
        }
        fprintf(stderr, " ");
        if (sgr_locus)
            fprintf(stderr, ANSI_ESCAPE_RESET);
    }
 
    if (!(log_flags & PG_LOG_FLAG_TERSE))
    {
        switch (part)
        {
            case PG_LOG_PRIMARY:
                switch (level)
                {
                    case PG_LOG_ERROR:
                        if (sgr_error)
                            fprintf(stderr, ANSI_ESCAPE_FMT, sgr_error);
                        fprintf(stderr, _("error: "));
                        if (log_logfile)
                            fprintf(log_logfile, _("error: "));
                        if (sgr_error)
                            fprintf(stderr, ANSI_ESCAPE_RESET);
                        break;
                    case PG_LOG_WARNING:
                        if (sgr_warning)
                            fprintf(stderr, ANSI_ESCAPE_FMT, sgr_warning);
                        fprintf(stderr, _("warning: "));
                        if (log_logfile)
                            fprintf(log_logfile, _("warning: "));
                        if (sgr_warning)
                            fprintf(stderr, ANSI_ESCAPE_RESET);
                        break;
                    default:
                        break;
                }
                break;
            case PG_LOG_DETAIL:
                if (sgr_note)
                    fprintf(stderr, ANSI_ESCAPE_FMT, sgr_note);
                fprintf(stderr, _("detail: "));
                if (log_logfile)
                    fprintf(log_logfile, _("detail: "));
                if (sgr_note)
                    fprintf(stderr, ANSI_ESCAPE_RESET);
                break;
            case PG_LOG_HINT:
                if (sgr_note)
                    fprintf(stderr, ANSI_ESCAPE_FMT, sgr_note);
                fprintf(stderr, _("hint: "));
                if (log_logfile)
                    fprintf(log_logfile, _("hint: "));
                if (sgr_note)
                    fprintf(stderr, ANSI_ESCAPE_RESET);
                break;
        }
    }
 
    errno = save_errno;
 
    va_copy(ap2, ap);
    required_len = vsnprintf(NULL, 0, fmt, ap2) + 1;
    va_end(ap2);
 
    buf = pg_malloc_extended(required_len, MCXT_ALLOC_NO_OOM);
 
    errno = save_errno;         /* malloc might change errno */
 
    if (!buf)
    {
        /* memory trouble, just print what we can and get out of here */
        vfprintf(stderr, fmt, ap);
        return;
    }
 
    vsnprintf(buf, required_len, fmt, ap);
 
    /* strip one newline, for PQerrorMessage() */
    if (required_len >= 2 && buf[required_len - 2] == '\n')
        buf[required_len - 2] = '\0';
 
    fprintf(stderr, "%s\n", buf);
    if (log_logfile)
    {
        fprintf(log_logfile, "%s\n", buf);
        fflush(log_logfile);
    }
 
    free(buf);
}