#include "postgres.h"
#include <fcntl.h>
#include <limits.h>
#include <signal.h>
#include <time.h>
#include <unistd.h>
#include <sys/stat.h>
#include "common/file_perm.h"
#include "lib/stringinfo.h"
#include "libpq/pqsignal.h"
#include "miscadmin.h"
#include "nodes/pg_list.h"
#include "pgstat.h"
#include "pgtime.h"
#include "port/pg_bitutils.h"
#include "postmaster/interrupt.h"
#include "postmaster/postmaster.h"
#include "postmaster/syslogger.h"
#include "storage/dsm.h"
#include "storage/fd.h"
#include "storage/ipc.h"
#include "storage/latch.h"
#include "storage/pg_shmem.h"
#include "tcop/tcopprot.h"
#include "utils/guc.h"
#include "utils/memutils.h"
#include "utils/ps_status.h"

Include dependency graph for syslogger.c:

Data Structures
struct	save_buffer

struct	SysloggerStartupData

Macros
#define	READ_BUF_SIZE (2 * PIPE_CHUNK_SIZE)

#define	LOGROTATE_SIGNAL_FILE "logrotate"

#define	NBUFFER_LISTS 256

Functions
static void	process_pipe_input (char logbuffer, int bytes_in_logbuffer)

static void	flush_pipe_input (char logbuffer, int bytes_in_logbuffer)

static FILE *	logfile_open (const char filename, const char mode, bool allow_errors)

static void	logfile_rotate (bool time_based_rotation, int size_rotation_for)

static bool	logfile_rotate_dest (bool time_based_rotation, int size_rotation_for, pg_time_t fntime, int target_dest, char last_file_name, FILE logFile)

static char *	logfile_getname (pg_time_t timestamp, const char *suffix)

static void	set_next_rotation_time (void)

static void	sigUsr1Handler (SIGNAL_ARGS)

static void	update_metainfo_datafile (void)

void	SysLoggerMain (char *startup_data, size_t startup_data_len)

int	SysLogger_Start (void)

void	write_syslogger_file (const char *buffer, int count, int destination)

bool	CheckLogrotateSignal (void)

void	RemoveLogrotateSignalFiles (void)

Variables
bool	Logging_collector = false

int	Log_RotationAge = HOURS_PER_DAY * MINS_PER_HOUR

int	Log_RotationSize = 10 * 1024

char *	Log_directory = NULL

char *	Log_filename = NULL

bool	Log_truncate_on_rotation = false

int	Log_file_mode = S_IRUSR \| S_IWUSR

bool	redirection_done

static pg_time_t	next_rotation_time

static bool	pipe_eof_seen = false

static bool	rotation_disabled = false

static FILE *	syslogFile = NULL

static FILE *	csvlogFile = NULL

static FILE *	jsonlogFile = NULL

NON_EXEC_STATIC pg_time_t	first_syslogger_file_time = 0

static char *	last_sys_file_name = NULL

static char *	last_csv_file_name = NULL

static char *	last_json_file_name = NULL

static List *	buffer_lists [NBUFFER_LISTS]

int	syslogPipe [2] = {-1, -1}

static volatile sig_atomic_t	rotation_requested = false

Macro Definition Documentation

◆ LOGROTATE_SIGNAL_FILE

#define LOGROTATE_SIGNAL_FILE "logrotate"

Definition at line 63 of file syslogger.c.

◆ NBUFFER_LISTS

#define NBUFFER_LISTS 256

Definition at line 111 of file syslogger.c.

◆ READ_BUF_SIZE

#define READ_BUF_SIZE (2 * PIPE_CHUNK_SIZE)

Definition at line 60 of file syslogger.c.

Function Documentation

◆ CheckLogrotateSignal()

bool CheckLogrotateSignal ( void )

Definition at line 1573 of file syslogger.c.

 {
     struct stat stat_buf;
  
     if (stat(LOGROTATE_SIGNAL_FILE, &stat_buf) == 0)
         return true;
  
     return false;
 }

References LOGROTATE_SIGNAL_FILE, and stat.

Referenced by process_pm_pmsignal().

◆ flush_pipe_input()

static void flush_pipe_input	(	char *	logbuffer,
		int *	bytes_in_logbuffer
	)

static

Definition at line 1043 of file syslogger.c.

 {
     int         i;
  
     /* Dump any incomplete protocol messages */
     for (i = 0; i < NBUFFER_LISTS; i++)
     {
         List       *list = buffer_lists[i];
         ListCell   *cell;
  
         foreach(cell, list)
         {
             save_buffer *buf = (save_buffer *) lfirst(cell);
  
             if (buf->pid != 0)
             {
                 StringInfo  str = &(buf->data);
  
                 write_syslogger_file(str->data, str->len,
                                      LOG_DESTINATION_STDERR);
                 /* Mark the buffer unused, and reclaim string storage */
                 buf->pid = 0;
                 pfree(str->data);
             }
         }
     }
  
     /*
      * Force out any remaining pipe data as-is; we don't bother trying to
      * remove any protocol headers that may exist in it.
      */
     if (*bytes_in_logbuffer > 0)
         write_syslogger_file(logbuffer, *bytes_in_logbuffer,
                              LOG_DESTINATION_STDERR);
     *bytes_in_logbuffer = 0;
 }

References buf, buffer_lists, i, lfirst, sort-test::list, LOG_DESTINATION_STDERR, NBUFFER_LISTS, pfree(), str, and write_syslogger_file().

Referenced by SysLoggerMain().

◆ logfile_getname()

static char * logfile_getname	(	pg_time_t	timestamp,
		const char *	suffix
	)

static

Definition at line 1411 of file syslogger.c.

 {
     char       *filename;
     int         len;
  
     filename = palloc(MAXPGPATH);
  
     snprintf(filename, MAXPGPATH, "%s/", Log_directory);
  
     len = strlen(filename);
  
     /* treat Log_filename as a strftime pattern */
     pg_strftime(filename + len, MAXPGPATH - len, Log_filename,
                 pg_localtime(&timestamp, log_timezone));
  
     if (suffix != NULL)
     {
         len = strlen(filename);
         if (len > 4 && (strcmp(filename + (len - 4), ".log") == 0))
             len -= 4;
         strlcpy(filename + len, suffix, MAXPGPATH - len);
     }
  
     return filename;
 }

References filename, len, Log_directory, Log_filename, log_timezone, MAXPGPATH, palloc(), pg_localtime(), pg_strftime(), snprintf, and strlcpy().

Referenced by logfile_rotate_dest(), SysLogger_Start(), and SysLoggerMain().

◆ logfile_open()

static FILE * logfile_open	(	const char *	filename,
		const char *	mode,
		bool	allow_errors
	)

static

Definition at line 1218 of file syslogger.c.

 {
     FILE       *fh;
     mode_t      oumask;
  
     /*
      * Note we do not let Log_file_mode disable IWUSR, since we certainly want
      * to be able to write the files ourselves.
      */
     oumask = umask((mode_t) ((~(Log_file_mode | S_IWUSR)) & (S_IRWXU | S_IRWXG | S_IRWXO)));
     fh = fopen(filename, mode);
     umask(oumask);
  
     if (fh)
     {
         setvbuf(fh, NULL, PG_IOLBF, 0);
  
 #ifdef WIN32
         /* use CRLF line endings on Windows */
         _setmode(_fileno(fh), _O_TEXT);
 #endif
     }
     else
     {
         int         save_errno = errno;
  
         ereport(allow_errors ? LOG : FATAL,
                 (errcode_for_file_access(),
                  errmsg("could not open log file \"%s\": %m",
                         filename)));
         errno = save_errno;
     }
  
     return fh;
 }

References ereport, errcode_for_file_access(), errmsg(), FATAL, filename, LOG, Log_file_mode, mode, PG_IOLBF, S_IRWXG, S_IRWXO, S_IRWXU, and S_IWUSR.

Referenced by logfile_rotate_dest(), and SysLogger_Start().

◆ logfile_rotate()

static void logfile_rotate	(	bool	time_based_rotation,
		int	size_rotation_for
	)

static

Definition at line 1362 of file syslogger.c.

 {
     pg_time_t   fntime;
  
     rotation_requested = false;
  
     /*
      * When doing a time-based rotation, invent the new logfile name based on
      * the planned rotation time, not current time, to avoid "slippage" in the
      * file name when we don't do the rotation immediately.
      */
     if (time_based_rotation)
         fntime = next_rotation_time;
     else
         fntime = time(NULL);
  
     /* file rotation for stderr */
     if (!logfile_rotate_dest(time_based_rotation, size_rotation_for, fntime,
                              LOG_DESTINATION_STDERR, &last_sys_file_name,
                              &syslogFile))
         return;
  
     /* file rotation for csvlog */
     if (!logfile_rotate_dest(time_based_rotation, size_rotation_for, fntime,
                              LOG_DESTINATION_CSVLOG, &last_csv_file_name,
                              &csvlogFile))
         return;
  
     /* file rotation for jsonlog */
     if (!logfile_rotate_dest(time_based_rotation, size_rotation_for, fntime,
                              LOG_DESTINATION_JSONLOG, &last_json_file_name,
                              &jsonlogFile))
         return;
  
     update_metainfo_datafile();
  
     set_next_rotation_time();
 }

References csvlogFile, jsonlogFile, last_csv_file_name, last_json_file_name, last_sys_file_name, LOG_DESTINATION_CSVLOG, LOG_DESTINATION_JSONLOG, LOG_DESTINATION_STDERR, logfile_rotate_dest(), next_rotation_time, rotation_requested, set_next_rotation_time(), syslogFile, and update_metainfo_datafile().

Referenced by SysLoggerMain().

◆ logfile_rotate_dest()

static bool logfile_rotate_dest	(	bool	time_based_rotation,
		int	size_rotation_for,
		pg_time_t	fntime,
		int	target_dest,
		char **	last_file_name,
		FILE **	logFile
	)

static

Definition at line 1263 of file syslogger.c.

 {
     char       *logFileExt = NULL;
     char       *filename;
     FILE       *fh;
  
     /*
      * If the target destination was just turned off, close the previous file
      * and unregister its data.  This cannot happen for stderr as syslogFile
      * is assumed to be always opened even if stderr is disabled in
      * log_destination.
      */
     if ((Log_destination & target_dest) == 0 &&
         target_dest != LOG_DESTINATION_STDERR)
     {
         if (*logFile != NULL)
             fclose(*logFile);
         *logFile = NULL;
         if (*last_file_name != NULL)
             pfree(*last_file_name);
         *last_file_name = NULL;
         return true;
     }
  
     /*
      * Leave if it is not time for a rotation or if the target destination has
      * no need to do a rotation based on the size of its file.
      */
     if (!time_based_rotation && (size_rotation_for & target_dest) == 0)
         return true;
  
     /* file extension depends on the destination type */
     if (target_dest == LOG_DESTINATION_STDERR)
         logFileExt = NULL;
     else if (target_dest == LOG_DESTINATION_CSVLOG)
         logFileExt = ".csv";
     else if (target_dest == LOG_DESTINATION_JSONLOG)
         logFileExt = ".json";
     else
     {
         /* cannot happen */
         Assert(false);
     }
  
     /* build the new file name */
     filename = logfile_getname(fntime, logFileExt);
  
     /*
      * Decide whether to overwrite or append.  We can overwrite if (a)
      * Log_truncate_on_rotation is set, (b) the rotation was triggered by
      * elapsed time and not something else, and (c) the computed file name is
      * different from what we were previously logging into.
      */
     if (Log_truncate_on_rotation && time_based_rotation &&
         *last_file_name != NULL &&
         strcmp(filename, *last_file_name) != 0)
         fh = logfile_open(filename, "w", true);
     else
         fh = logfile_open(filename, "a", true);
  
     if (!fh)
     {
         /*
          * ENFILE/EMFILE are not too surprising on a busy system; just keep
          * using the old file till we manage to get a new one.  Otherwise,
          * assume something's wrong with Log_directory and stop trying to
          * create files.
          */
         if (errno != ENFILE && errno != EMFILE)
         {
             ereport(LOG,
                     (errmsg("disabling automatic rotation (use SIGHUP to re-enable)")));
             rotation_disabled = true;
         }
  
         if (filename)
             pfree(filename);
         return false;
     }
  
     /* fill in the new information */
     if (*logFile != NULL)
         fclose(*logFile);
     *logFile = fh;
  
     /* instead of pfree'ing filename, remember it for next time */
     if (*last_file_name != NULL)
         pfree(*last_file_name);
     *last_file_name = filename;
  
     return true;
 }

References Assert, ereport, errmsg(), filename, LOG, Log_destination, LOG_DESTINATION_CSVLOG, LOG_DESTINATION_JSONLOG, LOG_DESTINATION_STDERR, Log_truncate_on_rotation, logfile_getname(), logfile_open(), pfree(), and rotation_disabled.

Referenced by logfile_rotate().

◆ process_pipe_input()

static void process_pipe_input	(	char *	logbuffer,
		int *	bytes_in_logbuffer
	)

static

Definition at line 880 of file syslogger.c.

 {
     char       *cursor = logbuffer;
     int         count = *bytes_in_logbuffer;
     int         dest = LOG_DESTINATION_STDERR;
  
     /* While we have enough for a header, process data... */
     while (count >= (int) (offsetof(PipeProtoHeader, data) + 1))
     {
         PipeProtoHeader p;
         int         chunklen;
         bits8       dest_flags;
  
         /* Do we have a valid header? */
         memcpy(&p, cursor, offsetof(PipeProtoHeader, data));
         dest_flags = p.flags & (PIPE_PROTO_DEST_STDERR |
                                 PIPE_PROTO_DEST_CSVLOG |
                                 PIPE_PROTO_DEST_JSONLOG);
         if (p.nuls[0] == '\0' && p.nuls[1] == '\0' &&
             p.len > 0 && p.len <= PIPE_MAX_PAYLOAD &&
             p.pid != 0 &&
             pg_number_of_ones[dest_flags] == 1)
         {
             List       *buffer_list;
             ListCell   *cell;
             save_buffer *existing_slot = NULL,
                        *free_slot = NULL;
             StringInfo  str;
  
             chunklen = PIPE_HEADER_SIZE + p.len;
  
             /* Fall out of loop if we don't have the whole chunk yet */
             if (count < chunklen)
                 break;
  
             if ((p.flags & PIPE_PROTO_DEST_STDERR) != 0)
                 dest = LOG_DESTINATION_STDERR;
             else if ((p.flags & PIPE_PROTO_DEST_CSVLOG) != 0)
                 dest = LOG_DESTINATION_CSVLOG;
             else if ((p.flags & PIPE_PROTO_DEST_JSONLOG) != 0)
                 dest = LOG_DESTINATION_JSONLOG;
             else
             {
                 /* this should never happen as of the header validation */
                 Assert(false);
             }
  
             /* Locate any existing buffer for this source pid */
             buffer_list = buffer_lists[p.pid % NBUFFER_LISTS];
             foreach(cell, buffer_list)
             {
                 save_buffer *buf = (save_buffer *) lfirst(cell);
  
                 if (buf->pid == p.pid)
                 {
                     existing_slot = buf;
                     break;
                 }
                 if (buf->pid == 0 && free_slot == NULL)
                     free_slot = buf;
             }
  
             if ((p.flags & PIPE_PROTO_IS_LAST) == 0)
             {
                 /*
                  * Save a complete non-final chunk in a per-pid buffer
                  */
                 if (existing_slot != NULL)
                 {
                     /* Add chunk to data from preceding chunks */
                     str = &(existing_slot->data);
                     appendBinaryStringInfo(str,
                                            cursor + PIPE_HEADER_SIZE,
                                            p.len);
                 }
                 else
                 {
                     /* First chunk of message, save in a new buffer */
                     if (free_slot == NULL)
                     {
                         /*
                          * Need a free slot, but there isn't one in the list,
                          * so create a new one and extend the list with it.
                          */
                         free_slot = palloc(sizeof(save_buffer));
                         buffer_list = lappend(buffer_list, free_slot);
                         buffer_lists[p.pid % NBUFFER_LISTS] = buffer_list;
                     }
                     free_slot->pid = p.pid;
                     str = &(free_slot->data);
                     initStringInfo(str);
                     appendBinaryStringInfo(str,
                                            cursor + PIPE_HEADER_SIZE,
                                            p.len);
                 }
             }
             else
             {
                 /*
                  * Final chunk --- add it to anything saved for that pid, and
                  * either way write the whole thing out.
                  */
                 if (existing_slot != NULL)
                 {
                     str = &(existing_slot->data);
                     appendBinaryStringInfo(str,
                                            cursor + PIPE_HEADER_SIZE,
                                            p.len);
                     write_syslogger_file(str->data, str->len, dest);
                     /* Mark the buffer unused, and reclaim string storage */
                     existing_slot->pid = 0;
                     pfree(str->data);
                 }
                 else
                 {
                     /* The whole message was one chunk, evidently. */
                     write_syslogger_file(cursor + PIPE_HEADER_SIZE, p.len,
                                          dest);
                 }
             }
  
             /* Finished processing this chunk */
             cursor += chunklen;
             count -= chunklen;
         }
         else
         {
             /* Process non-protocol data */
  
             /*
              * Look for the start of a protocol header.  If found, dump data
              * up to there and repeat the loop.  Otherwise, dump it all and
              * fall out of the loop.  (Note: we want to dump it all if at all
              * possible, so as to avoid dividing non-protocol messages across
              * logfiles.  We expect that in many scenarios, a non-protocol
              * message will arrive all in one read(), and we want to respect
              * the read() boundary if possible.)
              */
             for (chunklen = 1; chunklen < count; chunklen++)
             {
                 if (cursor[chunklen] == '\0')
                     break;
             }
             /* fall back on the stderr log as the destination */
             write_syslogger_file(cursor, chunklen, LOG_DESTINATION_STDERR);
             cursor += chunklen;
             count -= chunklen;
         }
     }
  
     /* We don't have a full chunk, so left-align what remains in the buffer */
     if (count > 0 && cursor != logbuffer)
         memmove(logbuffer, cursor, count);
     *bytes_in_logbuffer = count;
 }

References appendBinaryStringInfo(), Assert, buf, buffer_lists, save_buffer::data, data, generate_unaccent_rules::dest, PipeProtoHeader::flags, initStringInfo(), lappend(), PipeProtoHeader::len, lfirst, LOG_DESTINATION_CSVLOG, LOG_DESTINATION_JSONLOG, LOG_DESTINATION_STDERR, NBUFFER_LISTS, PipeProtoHeader::nuls, palloc(), pfree(), pg_number_of_ones, save_buffer::pid, PipeProtoHeader::pid, PIPE_HEADER_SIZE, PIPE_MAX_PAYLOAD, PIPE_PROTO_DEST_CSVLOG, PIPE_PROTO_DEST_JSONLOG, PIPE_PROTO_DEST_STDERR, PIPE_PROTO_IS_LAST, str, and write_syslogger_file().

Referenced by SysLoggerMain().

◆ RemoveLogrotateSignalFiles()

void RemoveLogrotateSignalFiles ( void )

Definition at line 1587 of file syslogger.c.

 {
     unlink(LOGROTATE_SIGNAL_FILE);
 }

References LOGROTATE_SIGNAL_FILE.

Referenced by PostmasterMain(), and process_pm_pmsignal().

◆ set_next_rotation_time()

static void set_next_rotation_time ( void )

static

Definition at line 1441 of file syslogger.c.

 {
     pg_time_t   now;
     struct pg_tm *tm;
     int         rotinterval;
  
     /* nothing to do if time-based rotation is disabled */
     if (Log_RotationAge <= 0)
         return;
  
     /*
      * The requirements here are to choose the next time > now that is a
      * "multiple" of the log rotation interval.  "Multiple" can be interpreted
      * fairly loosely.  In this version we align to log_timezone rather than
      * GMT.
      */
     rotinterval = Log_RotationAge * SECS_PER_MINUTE;    /* convert to seconds */
     now = (pg_time_t) time(NULL);
     tm = pg_localtime(&now, log_timezone);
     now += tm->tm_gmtoff;
     now -= now % rotinterval;
     now += rotinterval;
     now -= tm->tm_gmtoff;
     next_rotation_time = now;
 }

References Log_RotationAge, log_timezone, next_rotation_time, now(), pg_localtime(), SECS_PER_MINUTE, tm, and pg_tm::tm_gmtoff.

Referenced by logfile_rotate(), and SysLoggerMain().

◆ sigUsr1Handler()

static void sigUsr1Handler ( SIGNAL_ARGS )

static

Definition at line 1594 of file syslogger.c.

 {
     rotation_requested = true;
     SetLatch(MyLatch);
 }

References MyLatch, rotation_requested, and SetLatch().

Referenced by SysLoggerMain().

◆ SysLogger_Start()

int SysLogger_Start ( void )

Definition at line 595 of file syslogger.c.

 {
     pid_t       sysloggerPid;
     char       *filename;
 #ifdef EXEC_BACKEND
     SysloggerStartupData startup_data;
 #endif                          /* EXEC_BACKEND */
  
     if (!Logging_collector)
         return 0;
  
     /*
      * If first time through, create the pipe which will receive stderr
      * output.
      *
      * If the syslogger crashes and needs to be restarted, we continue to use
      * the same pipe (indeed must do so, since extant backends will be writing
      * into that pipe).
      *
      * This means the postmaster must continue to hold the read end of the
      * pipe open, so we can pass it down to the reincarnated syslogger. This
      * is a bit klugy but we have little choice.
      *
      * Also note that we don't bother counting the pipe FDs by calling
      * Reserve/ReleaseExternalFD.  There's no real need to account for them
      * accurately in the postmaster or syslogger process, and both ends of the
      * pipe will wind up closed in all other postmaster children.
      */
 #ifndef WIN32
     if (syslogPipe[0] < 0)
     {
         if (pipe(syslogPipe) < 0)
             ereport(FATAL,
                     (errcode_for_socket_access(),
                      errmsg("could not create pipe for syslog: %m")));
     }
 #else
     if (!syslogPipe[0])
     {
         SECURITY_ATTRIBUTES sa;
  
         memset(&sa, 0, sizeof(SECURITY_ATTRIBUTES));
         sa.nLength = sizeof(SECURITY_ATTRIBUTES);
         sa.bInheritHandle = TRUE;
  
         if (!CreatePipe(&syslogPipe[0], &syslogPipe[1], &sa, 32768))
             ereport(FATAL,
                     (errcode_for_file_access(),
                      errmsg("could not create pipe for syslog: %m")));
     }
 #endif
  
     /*
      * Create log directory if not present; ignore errors
      */
     (void) MakePGDirectory(Log_directory);
  
     /*
      * The initial logfile is created right in the postmaster, to verify that
      * the Log_directory is writable.  We save the reference time so that the
      * syslogger child process can recompute this file name.
      *
      * It might look a bit strange to re-do this during a syslogger restart,
      * but we must do so since the postmaster closed syslogFile after the
      * previous fork (and remembering that old file wouldn't be right anyway).
      * Note we always append here, we won't overwrite any existing file.  This
      * is consistent with the normal rules, because by definition this is not
      * a time-based rotation.
      */
     first_syslogger_file_time = time(NULL);
  
     filename = logfile_getname(first_syslogger_file_time, NULL);
  
     syslogFile = logfile_open(filename, "a", false);
  
     pfree(filename);
  
     /*
      * Likewise for the initial CSV log file, if that's enabled.  (Note that
      * we open syslogFile even when only CSV output is nominally enabled,
      * since some code paths will write to syslogFile anyway.)
      */
     if (Log_destination & LOG_DESTINATION_CSVLOG)
     {
         filename = logfile_getname(first_syslogger_file_time, ".csv");
  
         csvlogFile = logfile_open(filename, "a", false);
  
         pfree(filename);
     }
  
     /*
      * Likewise for the initial JSON log file, if that's enabled.  (Note that
      * we open syslogFile even when only JSON output is nominally enabled,
      * since some code paths will write to syslogFile anyway.)
      */
     if (Log_destination & LOG_DESTINATION_JSONLOG)
     {
         filename = logfile_getname(first_syslogger_file_time, ".json");
  
         jsonlogFile = logfile_open(filename, "a", false);
  
         pfree(filename);
     }
  
 #ifdef EXEC_BACKEND
     startup_data.syslogFile = syslogger_fdget(syslogFile);
     startup_data.csvlogFile = syslogger_fdget(csvlogFile);
     startup_data.jsonlogFile = syslogger_fdget(jsonlogFile);
     sysloggerPid = postmaster_child_launch(B_LOGGER, (char *) &startup_data, sizeof(startup_data), NULL);
 #else
     sysloggerPid = postmaster_child_launch(B_LOGGER, NULL, 0, NULL);
 #endif                          /* EXEC_BACKEND */
  
     if (sysloggerPid == -1)
     {
         ereport(LOG,
                 (errmsg("could not fork system logger: %m")));
         return 0;
     }
  
     /* success, in postmaster */
  
     /* now we redirect stderr, if not done already */
     if (!redirection_done)
     {
 #ifdef WIN32
         int         fd;
 #endif
  
         /*
          * Leave a breadcrumb trail when redirecting, in case the user forgets
          * that redirection is active and looks only at the original stderr
          * target file.
          */
         ereport(LOG,
                 (errmsg("redirecting log output to logging collector process"),
                  errhint("Future log output will appear in directory \"%s\".",
                          Log_directory)));
  
 #ifndef WIN32
         fflush(stdout);
         if (dup2(syslogPipe[1], STDOUT_FILENO) < 0)
             ereport(FATAL,
                     (errcode_for_file_access(),
                      errmsg("could not redirect stdout: %m")));
         fflush(stderr);
         if (dup2(syslogPipe[1], STDERR_FILENO) < 0)
             ereport(FATAL,
                     (errcode_for_file_access(),
                      errmsg("could not redirect stderr: %m")));
         /* Now we are done with the write end of the pipe. */
         close(syslogPipe[1]);
         syslogPipe[1] = -1;
 #else
  
         /*
          * open the pipe in binary mode and make sure stderr is binary after
          * it's been dup'ed into, to avoid disturbing the pipe chunking
          * protocol.
          */
         fflush(stderr);
         fd = _open_osfhandle((intptr_t) syslogPipe[1],
                              _O_APPEND | _O_BINARY);
         if (dup2(fd, STDERR_FILENO) < 0)
             ereport(FATAL,
                     (errcode_for_file_access(),
                      errmsg("could not redirect stderr: %m")));
         close(fd);
         _setmode(STDERR_FILENO, _O_BINARY);
  
         /*
          * Now we are done with the write end of the pipe.  CloseHandle() must
          * not be called because the preceding close() closes the underlying
          * handle.
          */
         syslogPipe[1] = 0;
 #endif
         redirection_done = true;
     }
  
     /* postmaster will never write the file(s); close 'em */
     fclose(syslogFile);
     syslogFile = NULL;
     if (csvlogFile != NULL)
     {
         fclose(csvlogFile);
         csvlogFile = NULL;
     }
     if (jsonlogFile != NULL)
     {
         fclose(jsonlogFile);
         jsonlogFile = NULL;
     }
     return (int) sysloggerPid;
 }

References B_LOGGER, close, csvlogFile, SysloggerStartupData::csvlogFile, ereport, errcode_for_file_access(), errcode_for_socket_access(), errhint(), errmsg(), FATAL, fd(), fflush(), filename, first_syslogger_file_time, jsonlogFile, SysloggerStartupData::jsonlogFile, LOG, Log_destination, LOG_DESTINATION_CSVLOG, LOG_DESTINATION_JSONLOG, Log_directory, logfile_getname(), logfile_open(), Logging_collector, MakePGDirectory(), pfree(), postmaster_child_launch(), redirection_done, STDERR_FILENO, generate_unaccent_rules::stdout, STDOUT_FILENO, syslogFile, SysloggerStartupData::syslogFile, and syslogPipe.

Referenced by PostmasterMain(), process_pm_child_exit(), and ServerLoop().

◆ SysLoggerMain()

void SysLoggerMain	(	char *	startup_data,
		size_t	startup_data_len
	)

Definition at line 167 of file syslogger.c.

 {
 #ifndef WIN32
     char        logbuffer[READ_BUF_SIZE];
     int         bytes_in_logbuffer = 0;
 #endif
     char       *currentLogDir;
     char       *currentLogFilename;
     int         currentLogRotationAge;
     pg_time_t   now;
     WaitEventSet *wes;
  
     /*
      * Re-open the error output files that were opened by SysLogger_Start().
      *
      * We expect this will always succeed, which is too optimistic, but if it
      * fails there's not a lot we can do to report the problem anyway.  As
      * coded, we'll just crash on a null pointer dereference after failure...
      */
 #ifdef EXEC_BACKEND
     {
         SysloggerStartupData *slsdata = (SysloggerStartupData *) startup_data;
  
         Assert(startup_data_len == sizeof(*slsdata));
         syslogFile = syslogger_fdopen(slsdata->syslogFile);
         csvlogFile = syslogger_fdopen(slsdata->csvlogFile);
         jsonlogFile = syslogger_fdopen(slsdata->jsonlogFile);
     }
 #else
     Assert(startup_data_len == 0);
 #endif
  
     /*
      * Now that we're done reading the startup data, release postmaster's
      * working memory context.
      */
     if (PostmasterContext)
     {
         MemoryContextDelete(PostmasterContext);
         PostmasterContext = NULL;
     }
  
     now = MyStartTime;
  
     MyBackendType = B_LOGGER;
     init_ps_display(NULL);
  
     /*
      * If we restarted, our stderr is already redirected into our own input
      * pipe.  This is of course pretty useless, not to mention that it
      * interferes with detecting pipe EOF.  Point stderr to /dev/null. This
      * assumes that all interesting messages generated in the syslogger will
      * come through elog.c and will be sent to write_syslogger_file.
      */
     if (redirection_done)
     {
         int         fd = open(DEVNULL, O_WRONLY, 0);
  
         /*
          * The closes might look redundant, but they are not: we want to be
          * darn sure the pipe gets closed even if the open failed.  We can
          * survive running with stderr pointing nowhere, but we can't afford
          * to have extra pipe input descriptors hanging around.
          *
          * As we're just trying to reset these to go to DEVNULL, there's not
          * much point in checking for failure from the close/dup2 calls here,
          * if they fail then presumably the file descriptors are closed and
          * any writes will go into the bitbucket anyway.
          */
         close(STDOUT_FILENO);
         close(STDERR_FILENO);
         if (fd != -1)
         {
             (void) dup2(fd, STDOUT_FILENO);
             (void) dup2(fd, STDERR_FILENO);
             close(fd);
         }
     }
  
     /*
      * Syslogger's own stderr can't be the syslogPipe, so set it back to text
      * mode if we didn't just close it. (It was set to binary in
      * SubPostmasterMain).
      */
 #ifdef WIN32
     else
         _setmode(STDERR_FILENO, _O_TEXT);
 #endif
  
     /*
      * Also close our copy of the write end of the pipe.  This is needed to
      * ensure we can detect pipe EOF correctly.  (But note that in the restart
      * case, the postmaster already did this.)
      */
 #ifndef WIN32
     if (syslogPipe[1] >= 0)
         close(syslogPipe[1]);
     syslogPipe[1] = -1;
 #else
     if (syslogPipe[1])
         CloseHandle(syslogPipe[1]);
     syslogPipe[1] = 0;
 #endif
  
     /*
      * Properly accept or ignore signals the postmaster might send us
      *
      * Note: we ignore all termination signals, and instead exit only when all
      * upstream processes are gone, to ensure we don't miss any dying gasps of
      * broken backends...
      */
  
     pqsignal(SIGHUP, SignalHandlerForConfigReload); /* set flag to read config
                                                      * file */
     pqsignal(SIGINT, SIG_IGN);
     pqsignal(SIGTERM, SIG_IGN);
     pqsignal(SIGQUIT, SIG_IGN);
     pqsignal(SIGALRM, SIG_IGN);
     pqsignal(SIGPIPE, SIG_IGN);
     pqsignal(SIGUSR1, sigUsr1Handler);  /* request log rotation */
     pqsignal(SIGUSR2, SIG_IGN);
  
     /*
      * Reset some signals that are accepted by postmaster but not here
      */
     pqsignal(SIGCHLD, SIG_DFL);
  
     sigprocmask(SIG_SETMASK, &UnBlockSig, NULL);
  
 #ifdef WIN32
     /* Fire up separate data transfer thread */
     InitializeCriticalSection(&sysloggerSection);
     EnterCriticalSection(&sysloggerSection);
  
     threadHandle = (HANDLE) _beginthreadex(NULL, 0, pipeThread, NULL, 0, NULL);
     if (threadHandle == 0)
         elog(FATAL, "could not create syslogger data transfer thread: %m");
 #endif                          /* WIN32 */
  
     /*
      * Remember active logfiles' name(s).  We recompute 'em from the reference
      * time because passing down just the pg_time_t is a lot cheaper than
      * passing a whole file path in the EXEC_BACKEND case.
      */
     last_sys_file_name = logfile_getname(first_syslogger_file_time, NULL);
     if (csvlogFile != NULL)
         last_csv_file_name = logfile_getname(first_syslogger_file_time, ".csv");
     if (jsonlogFile != NULL)
         last_json_file_name = logfile_getname(first_syslogger_file_time, ".json");
  
     /* remember active logfile parameters */
     currentLogDir = pstrdup(Log_directory);
     currentLogFilename = pstrdup(Log_filename);
     currentLogRotationAge = Log_RotationAge;
     /* set next planned rotation time */
     set_next_rotation_time();
     update_metainfo_datafile();
  
     /*
      * Reset whereToSendOutput, as the postmaster will do (but hasn't yet, at
      * the point where we forked).  This prevents duplicate output of messages
      * from syslogger itself.
      */
     whereToSendOutput = DestNone;
  
     /*
      * Set up a reusable WaitEventSet object we'll use to wait for our latch,
      * and (except on Windows) our socket.
      *
      * Unlike all other postmaster child processes, we'll ignore postmaster
      * death because we want to collect final log output from all backends and
      * then exit last.  We'll do that by running until we see EOF on the
      * syslog pipe, which implies that all other backends have exited
      * (including the postmaster).
      */
     wes = CreateWaitEventSet(NULL, 2);
     AddWaitEventToSet(wes, WL_LATCH_SET, PGINVALID_SOCKET, MyLatch, NULL);
 #ifndef WIN32
     AddWaitEventToSet(wes, WL_SOCKET_READABLE, syslogPipe[0], NULL, NULL);
 #endif
  
     /* main worker loop */
     for (;;)
     {
         bool        time_based_rotation = false;
         int         size_rotation_for = 0;
         long        cur_timeout;
         WaitEvent   event;
  
 #ifndef WIN32
         int         rc;
 #endif
  
         /* Clear any already-pending wakeups */
         ResetLatch(MyLatch);
  
         /*
          * Process any requests or signals received recently.
          */
         if (ConfigReloadPending)
         {
             ConfigReloadPending = false;
             ProcessConfigFile(PGC_SIGHUP);
  
             /*
              * Check if the log directory or filename pattern changed in
              * postgresql.conf. If so, force rotation to make sure we're
              * writing the logfiles in the right place.
              */
             if (strcmp(Log_directory, currentLogDir) != 0)
             {
                 pfree(currentLogDir);
                 currentLogDir = pstrdup(Log_directory);
                 rotation_requested = true;
  
                 /*
                  * Also, create new directory if not present; ignore errors
                  */
                 (void) MakePGDirectory(Log_directory);
             }
             if (strcmp(Log_filename, currentLogFilename) != 0)
             {
                 pfree(currentLogFilename);
                 currentLogFilename = pstrdup(Log_filename);
                 rotation_requested = true;
             }
  
             /*
              * Force a rotation if CSVLOG output was just turned on or off and
              * we need to open or close csvlogFile accordingly.
              */
             if (((Log_destination & LOG_DESTINATION_CSVLOG) != 0) !=
                 (csvlogFile != NULL))
                 rotation_requested = true;
  
             /*
              * Force a rotation if JSONLOG output was just turned on or off
              * and we need to open or close jsonlogFile accordingly.
              */
             if (((Log_destination & LOG_DESTINATION_JSONLOG) != 0) !=
                 (jsonlogFile != NULL))
                 rotation_requested = true;
  
             /*
              * If rotation time parameter changed, reset next rotation time,
              * but don't immediately force a rotation.
              */
             if (currentLogRotationAge != Log_RotationAge)
             {
                 currentLogRotationAge = Log_RotationAge;
                 set_next_rotation_time();
             }
  
             /*
              * If we had a rotation-disabling failure, re-enable rotation
              * attempts after SIGHUP, and force one immediately.
              */
             if (rotation_disabled)
             {
                 rotation_disabled = false;
                 rotation_requested = true;
             }
  
             /*
              * Force rewriting last log filename when reloading configuration.
              * Even if rotation_requested is false, log_destination may have
              * been changed and we don't want to wait the next file rotation.
              */
             update_metainfo_datafile();
         }
  
         if (Log_RotationAge > 0 && !rotation_disabled)
         {
             /* Do a logfile rotation if it's time */
             now = (pg_time_t) time(NULL);
             if (now >= next_rotation_time)
                 rotation_requested = time_based_rotation = true;
         }
  
         if (!rotation_requested && Log_RotationSize > 0 && !rotation_disabled)
         {
             /* Do a rotation if file is too big */
             if (ftell(syslogFile) >= Log_RotationSize * 1024L)
             {
                 rotation_requested = true;
                 size_rotation_for |= LOG_DESTINATION_STDERR;
             }
             if (csvlogFile != NULL &&
                 ftell(csvlogFile) >= Log_RotationSize * 1024L)
             {
                 rotation_requested = true;
                 size_rotation_for |= LOG_DESTINATION_CSVLOG;
             }
             if (jsonlogFile != NULL &&
                 ftell(jsonlogFile) >= Log_RotationSize * 1024L)
             {
                 rotation_requested = true;
                 size_rotation_for |= LOG_DESTINATION_JSONLOG;
             }
         }
  
         if (rotation_requested)
         {
             /*
              * Force rotation when both values are zero. It means the request
              * was sent by pg_rotate_logfile() or "pg_ctl logrotate".
              */
             if (!time_based_rotation && size_rotation_for == 0)
                 size_rotation_for = LOG_DESTINATION_STDERR |
                     LOG_DESTINATION_CSVLOG |
                     LOG_DESTINATION_JSONLOG;
             logfile_rotate(time_based_rotation, size_rotation_for);
         }
  
         /*
          * Calculate time till next time-based rotation, so that we don't
          * sleep longer than that.  We assume the value of "now" obtained
          * above is still close enough.  Note we can't make this calculation
          * until after calling logfile_rotate(), since it will advance
          * next_rotation_time.
          *
          * Also note that we need to beware of overflow in calculation of the
          * timeout: with large settings of Log_RotationAge, next_rotation_time
          * could be more than INT_MAX msec in the future.  In that case we'll
          * wait no more than INT_MAX msec, and try again.
          */
         if (Log_RotationAge > 0 && !rotation_disabled)
         {
             pg_time_t   delay;
  
             delay = next_rotation_time - now;
             if (delay > 0)
             {
                 if (delay > INT_MAX / 1000)
                     delay = INT_MAX / 1000;
                 cur_timeout = delay * 1000L;    /* msec */
             }
             else
                 cur_timeout = 0;
         }
         else
             cur_timeout = -1L;
  
         /*
          * Sleep until there's something to do
          */
 #ifndef WIN32
         rc = WaitEventSetWait(wes, cur_timeout, &event, 1,
                               WAIT_EVENT_SYSLOGGER_MAIN);
  
         if (rc == 1 && event.events == WL_SOCKET_READABLE)
         {
             int         bytesRead;
  
             bytesRead = read(syslogPipe[0],
                              logbuffer + bytes_in_logbuffer,
                              sizeof(logbuffer) - bytes_in_logbuffer);
             if (bytesRead < 0)
             {
                 if (errno != EINTR)
                     ereport(LOG,
                             (errcode_for_socket_access(),
                              errmsg("could not read from logger pipe: %m")));
             }
             else if (bytesRead > 0)
             {
                 bytes_in_logbuffer += bytesRead;
                 process_pipe_input(logbuffer, &bytes_in_logbuffer);
                 continue;
             }
             else
             {
                 /*
                  * Zero bytes read when select() is saying read-ready means
                  * EOF on the pipe: that is, there are no longer any processes
                  * with the pipe write end open.  Therefore, the postmaster
                  * and all backends are shut down, and we are done.
                  */
                 pipe_eof_seen = true;
  
                 /* if there's any data left then force it out now */
                 flush_pipe_input(logbuffer, &bytes_in_logbuffer);
             }
         }
 #else                           /* WIN32 */
  
         /*
          * On Windows we leave it to a separate thread to transfer data and
          * detect pipe EOF.  The main thread just wakes up to handle SIGHUP
          * and rotation conditions.
          *
          * Server code isn't generally thread-safe, so we ensure that only one
          * of the threads is active at a time by entering the critical section
          * whenever we're not sleeping.
          */
         LeaveCriticalSection(&sysloggerSection);
  
         (void) WaitEventSetWait(wes, cur_timeout, &event, 1,
                                 WAIT_EVENT_SYSLOGGER_MAIN);
  
         EnterCriticalSection(&sysloggerSection);
 #endif                          /* WIN32 */
  
         if (pipe_eof_seen)
         {
             /*
              * seeing this message on the real stderr is annoying - so we make
              * it DEBUG1 to suppress in normal use.
              */
             ereport(DEBUG1,
                     (errmsg_internal("logger shutting down")));
  
             /*
              * Normal exit from the syslogger is here.  Note that we
              * deliberately do not close syslogFile before exiting; this is to
              * allow for the possibility of elog messages being generated
              * inside proc_exit.  Regular exit() will take care of flushing
              * and closing stdio channels.
              */
             proc_exit(0);
         }
     }
 }

References AddWaitEventToSet(), Assert, B_LOGGER, close, ConfigReloadPending, CreateWaitEventSet(), csvlogFile, SysloggerStartupData::csvlogFile, DEBUG1, DestNone, DEVNULL, EINTR, elog, ereport, errcode_for_socket_access(), errmsg(), errmsg_internal(), WaitEvent::events, FATAL, fd(), first_syslogger_file_time, flush_pipe_input(), init_ps_display(), jsonlogFile, SysloggerStartupData::jsonlogFile, last_csv_file_name, last_json_file_name, last_sys_file_name, LOG, Log_destination, LOG_DESTINATION_CSVLOG, LOG_DESTINATION_JSONLOG, LOG_DESTINATION_STDERR, Log_directory, Log_filename, Log_RotationAge, Log_RotationSize, logfile_getname(), logfile_rotate(), MakePGDirectory(), MemoryContextDelete(), MyBackendType, MyLatch, MyStartTime, next_rotation_time, now(), pfree(), PGC_SIGHUP, PGINVALID_SOCKET, pipe_eof_seen, PostmasterContext, pqsignal(), proc_exit(), process_pipe_input(), ProcessConfigFile(), pstrdup(), read, READ_BUF_SIZE, redirection_done, ResetLatch(), rotation_disabled, rotation_requested, set_next_rotation_time(), SIG_DFL, SIG_IGN, SIGALRM, SIGCHLD, SIGHUP, SignalHandlerForConfigReload(), SIGPIPE, SIGQUIT, SIGUSR1, sigUsr1Handler(), SIGUSR2, STDERR_FILENO, STDOUT_FILENO, syslogFile, SysloggerStartupData::syslogFile, syslogPipe, UnBlockSig, update_metainfo_datafile(), WaitEventSetWait(), whereToSendOutput, WL_LATCH_SET, and WL_SOCKET_READABLE.

◆ update_metainfo_datafile()

static void update_metainfo_datafile ( void )

static

Definition at line 1476 of file syslogger.c.

 {
     FILE       *fh;
     mode_t      oumask;
  
     if (!(Log_destination & LOG_DESTINATION_STDERR) &&
         !(Log_destination & LOG_DESTINATION_CSVLOG) &&
         !(Log_destination & LOG_DESTINATION_JSONLOG))
     {
         if (unlink(LOG_METAINFO_DATAFILE) < 0 && errno != ENOENT)
             ereport(LOG,
                     (errcode_for_file_access(),
                      errmsg("could not remove file \"%s\": %m",
                             LOG_METAINFO_DATAFILE)));
         return;
     }
  
     /* use the same permissions as the data directory for the new file */
     oumask = umask(pg_mode_mask);
     fh = fopen(LOG_METAINFO_DATAFILE_TMP, "w");
     umask(oumask);
  
     if (fh)
     {
         setvbuf(fh, NULL, PG_IOLBF, 0);
  
 #ifdef WIN32
         /* use CRLF line endings on Windows */
         _setmode(_fileno(fh), _O_TEXT);
 #endif
     }
     else
     {
         ereport(LOG,
                 (errcode_for_file_access(),
                  errmsg("could not open file \"%s\": %m",
                         LOG_METAINFO_DATAFILE_TMP)));
         return;
     }
  
     if (last_sys_file_name && (Log_destination & LOG_DESTINATION_STDERR))
     {
         if (fprintf(fh, "stderr %s\n", last_sys_file_name) < 0)
         {
             ereport(LOG,
                     (errcode_for_file_access(),
                      errmsg("could not write file \"%s\": %m",
                             LOG_METAINFO_DATAFILE_TMP)));
             fclose(fh);
             return;
         }
     }
  
     if (last_csv_file_name && (Log_destination & LOG_DESTINATION_CSVLOG))
     {
         if (fprintf(fh, "csvlog %s\n", last_csv_file_name) < 0)
         {
             ereport(LOG,
                     (errcode_for_file_access(),
                      errmsg("could not write file \"%s\": %m",
                             LOG_METAINFO_DATAFILE_TMP)));
             fclose(fh);
             return;
         }
     }
  
     if (last_json_file_name && (Log_destination & LOG_DESTINATION_JSONLOG))
     {
         if (fprintf(fh, "jsonlog %s\n", last_json_file_name) < 0)
         {
             ereport(LOG,
                     (errcode_for_file_access(),
                      errmsg("could not write file \"%s\": %m",
                             LOG_METAINFO_DATAFILE_TMP)));
             fclose(fh);
             return;
         }
     }
     fclose(fh);
  
     if (rename(LOG_METAINFO_DATAFILE_TMP, LOG_METAINFO_DATAFILE) != 0)
         ereport(LOG,
                 (errcode_for_file_access(),
                  errmsg("could not rename file \"%s\" to \"%s\": %m",
                         LOG_METAINFO_DATAFILE_TMP, LOG_METAINFO_DATAFILE)));
 }

References ereport, errcode_for_file_access(), errmsg(), fprintf, last_csv_file_name, last_json_file_name, last_sys_file_name, LOG, Log_destination, LOG_DESTINATION_CSVLOG, LOG_DESTINATION_JSONLOG, LOG_DESTINATION_STDERR, LOG_METAINFO_DATAFILE, LOG_METAINFO_DATAFILE_TMP, PG_IOLBF, and pg_mode_mask.

Referenced by logfile_rotate(), and SysLoggerMain().

◆ write_syslogger_file()

void write_syslogger_file	(	const char *	buffer,
		int	count,
		int	destination
	)

Definition at line 1094 of file syslogger.c.

 {
     int         rc;
     FILE       *logfile;
  
     /*
      * If we're told to write to a structured log file, but it's not open,
      * dump the data to syslogFile (which is always open) instead.  This can
      * happen if structured output is enabled after postmaster start and we've
      * been unable to open logFile.  There are also race conditions during a
      * parameter change whereby backends might send us structured output
      * before we open the logFile or after we close it.  Writing formatted
      * output to the regular log file isn't great, but it beats dropping log
      * output on the floor.
      *
      * Think not to improve this by trying to open logFile on-the-fly.  Any
      * failure in that would lead to recursion.
      */
     if ((destination & LOG_DESTINATION_CSVLOG) && csvlogFile != NULL)
         logfile = csvlogFile;
     else if ((destination & LOG_DESTINATION_JSONLOG) && jsonlogFile != NULL)
         logfile = jsonlogFile;
     else
         logfile = syslogFile;
  
     rc = fwrite(buffer, 1, count, logfile);
  
     /*
      * Try to report any failure.  We mustn't use ereport because it would
      * just recurse right back here, but write_stderr is OK: it will write
      * either to the postmaster's original stderr, or to /dev/null, but never
      * to our input pipe which would result in a different sort of looping.
      */
     if (rc != count)
         write_stderr("could not write to log file: %m\n");
 }