syslogger.h File Reference

#include <limits.h>

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Data Structures
struct	PipeProtoHeader
union	PipeProtoChunk

Macros
#define	PIPE_CHUNK_SIZE   512
#define	PIPE_HEADER_SIZE   offsetof(PipeProtoHeader, data)
#define	PIPE_MAX_PAYLOAD   ((int) (PIPE_CHUNK_SIZE - PIPE_HEADER_SIZE))
#define	PIPE_PROTO_IS_LAST   0x01 /* last chunk of message? */
#define	PIPE_PROTO_DEST_STDERR   0x10
#define	PIPE_PROTO_DEST_CSVLOG   0x20
#define	PIPE_PROTO_DEST_JSONLOG   0x40
#define	LOG_METAINFO_DATAFILE   "current_logfiles"
#define	LOG_METAINFO_DATAFILE_TMP   LOG_METAINFO_DATAFILE ".tmp"

Functions
int	SysLogger_Start (void)
void	write_syslogger_file (const char *buffer, int count, int destination)
bool	CheckLogrotateSignal (void)
void	RemoveLogrotateSignalFiles (void)

Variables
PGDLLIMPORT bool	Logging_collector
PGDLLIMPORT int	Log_RotationAge
PGDLLIMPORT int	Log_RotationSize
PGDLLIMPORT char *	Log_directory
PGDLLIMPORT char *	Log_filename
PGDLLIMPORT bool	Log_truncate_on_rotation
PGDLLIMPORT int	Log_file_mode
PGDLLIMPORT int	syslogPipe [2]

Macro Definition Documentation

LOG_METAINFO_DATAFILE

#define LOG_METAINFO_DATAFILE   "current_logfiles"

Definition at line 100 of file syslogger.h.

LOG_METAINFO_DATAFILE_TMP

#define LOG_METAINFO_DATAFILE_TMP   LOG_METAINFO_DATAFILE ".tmp"

Definition at line 101 of file syslogger.h.

PIPE_CHUNK_SIZE

#define PIPE_CHUNK_SIZE   512

Definition at line 41 of file syslogger.h.

PIPE_HEADER_SIZE

#define PIPE_HEADER_SIZE   offsetof(PipeProtoHeader, data)

Definition at line 59 of file syslogger.h.

PIPE_MAX_PAYLOAD

#define PIPE_MAX_PAYLOAD   ((int) (PIPE_CHUNK_SIZE - PIPE_HEADER_SIZE))

Definition at line 60 of file syslogger.h.

PIPE_PROTO_DEST_CSVLOG

#define PIPE_PROTO_DEST_CSVLOG   0x20

Definition at line 66 of file syslogger.h.

PIPE_PROTO_DEST_JSONLOG

#define PIPE_PROTO_DEST_JSONLOG   0x40

Definition at line 67 of file syslogger.h.

PIPE_PROTO_DEST_STDERR

#define PIPE_PROTO_DEST_STDERR   0x10

Definition at line 65 of file syslogger.h.

PIPE_PROTO_IS_LAST

#define PIPE_PROTO_IS_LAST   0x01 /* last chunk of message? */

Definition at line 63 of file syslogger.h.

Function Documentation

CheckLogrotateSignal()

bool CheckLogrotateSignal

(

void

)

Definition at line 1622 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().

RemoveLogrotateSignalFiles()

void RemoveLogrotateSignalFiles

(

void

)

Definition at line 1636 of file syslogger.c.

{
    unlink(LOGROTATE_SIGNAL_FILE);
}

References LOGROTATE_SIGNAL_FILE.

Referenced by PostmasterMain(), and process_pm_pmsignal().

SysLogger_Start()

int SysLogger_Start

(

void

)

Definition at line 567 of file syslogger.c.

{
    pid_t       sysloggerPid;
    char       *filename;
 
    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
    switch ((sysloggerPid = syslogger_forkexec()))
#else
    switch ((sysloggerPid = fork_process()))
#endif
    {
        case -1:
            ereport(LOG,
                    (errmsg("could not fork system logger: %m")));
            return 0;
 
#ifndef EXEC_BACKEND
        case 0:
            /* in postmaster child ... */
            InitPostmasterChild();
 
            /* Close the postmaster's sockets */
            ClosePostmasterPorts(true);
 
            /* Drop our connection to postmaster's shared memory, as well */
            dsm_detach_all();
            PGSharedMemoryDetach();
 
            /* do the work */
            SysLoggerMain(0, NULL);
            break;
#endif
 
        default:
            /* 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;
    }
 
    /* we should never reach here */
    return 0;
}

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

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

write_syslogger_file()

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

Definition at line 1143 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: %s\n", strerror(errno));
}

References csvlogFile, jsonlogFile, LOG_DESTINATION_CSVLOG, LOG_DESTINATION_JSONLOG, logfile, strerror, syslogFile, and write_stderr.

Referenced by flush_pipe_input(), process_pipe_input(), send_message_to_server_log(), write_csvlog(), and write_jsonlog().

Variable Documentation

Log_directory

PGDLLIMPORT char* Log_directory

extern

Definition at line 74 of file syslogger.c.

Referenced by convert_and_check_filename(), logfile_getname(), pg_logdir_ls_internal(), pg_ls_logdir(), SysLogger_Start(), and SysLoggerMain().

Log_file_mode

PGDLLIMPORT int Log_file_mode

extern

Definition at line 77 of file syslogger.c.

Referenced by logfile_open(), and show_log_file_mode().

Log_filename

PGDLLIMPORT char* Log_filename

extern

Definition at line 75 of file syslogger.c.

Referenced by logfile_getname(), pg_logdir_ls_internal(), and SysLoggerMain().

Log_RotationAge

PGDLLIMPORT int Log_RotationAge

extern

Definition at line 72 of file syslogger.c.

Referenced by set_next_rotation_time(), and SysLoggerMain().

Log_RotationSize

PGDLLIMPORT int Log_RotationSize

extern

Definition at line 73 of file syslogger.c.

Referenced by SysLoggerMain().

Log_truncate_on_rotation

PGDLLIMPORT bool Log_truncate_on_rotation

extern

Definition at line 76 of file syslogger.c.

Referenced by logfile_rotate_dest().

Logging_collector

PGDLLIMPORT bool Logging_collector

extern

Definition at line 71 of file syslogger.c.

Referenced by pg_rotate_logfile(), pg_rotate_logfile_v2(), ServerLoop(), and SysLogger_Start().

syslogPipe

PGDLLIMPORT int syslogPipe[2]

extern

Definition at line 117 of file syslogger.c.

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