/*
* Main entry point for syslogger process
* argc/argv parameters are valid only in EXEC_BACKEND case.
*/
NON_EXEC_STATIC void
SysLoggerMain(int argc, char *argv[])
{
#ifndef WIN32
char logbuffer[READ_BUF_SIZE];
int bytes_in_logbuffer = 0;
#endif
char *currentLogDir;
char *currentLogFilename;
int currentLogRotationAge;
IsUnderPostmaster = true; /* we are a postmaster subprocess now */
MyProcPid = getpid(); /* reset MyProcPid */
MyStartTime = time(NULL); /* set our start time in case we call elog */
#ifdef EXEC_BACKEND
syslogger_parseArgs(argc, argv);
#endif /* EXEC_BACKEND */
am_syslogger = true;
init_ps_display("logger process", "", "", "");
/*
* 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.
*/
close(fileno(stdout));
close(fileno(stderr));
if (fd != -1)
{
dup2(fd, fileno(stdout));
dup2(fd, fileno(stderr));
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(_fileno(stderr), _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
/*
* If possible, make this process a group leader, so that the postmaster
* can signal any child processes too. (syslogger probably never has any
* child processes, but for consistency we make all postmaster child
* processes do this.)
*/
#ifdef HAVE_SETSID
if (setsid() < 0)
elog(FATAL, "setsid() failed: %m");
#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, sigHupHandler); /* 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);
pqsignal(SIGTTIN, SIG_DFL);
pqsignal(SIGTTOU, SIG_DFL);
pqsignal(SIGCONT, SIG_DFL);
pqsignal(SIGWINCH, SIG_DFL);
PG_SETMASK(&UnBlockSig);
#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 logfile parameters */
currentLogDir = pstrdup(Log_directory);
currentLogFilename = pstrdup(Log_filename);
currentLogRotationAge = Log_RotationAge;
/* set next planned rotation time */
set_next_rotation_time();
/* main worker loop */
for (;;)
{
bool time_based_rotation = false;
int size_rotation_for = 0;
#ifndef WIN32
int bytesRead;
int rc;
fd_set rfds;
struct timeval timeout;
#endif
if (got_SIGHUP)
{
got_SIGHUP = 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;
}
if (strcmp(Log_filename, currentLogFilename) != 0)
{
pfree(currentLogFilename);
currentLogFilename = pstrdup(Log_filename);
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 (!rotation_requested && Log_RotationAge > 0)
{
/* Do a logfile rotation if it's time */
pg_time_t now = (pg_time_t) time(NULL);
if (now >= next_rotation_time)
rotation_requested = time_based_rotation = true;
}
if (!rotation_requested && Log_RotationSize > 0)
{
/* 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 (rotation_requested)
{
/*
* Force rotation when both values are zero. It means the request
* was sent by pg_rotate_logfile.
*/
if (!time_based_rotation && size_rotation_for == 0)
size_rotation_for = LOG_DESTINATION_STDERR | LOG_DESTINATION_CSVLOG;
logfile_rotate(time_based_rotation, size_rotation_for);
}
#ifndef WIN32
/*
* Wait for some data, timing out after 1 second
*/
FD_ZERO(&rfds);
FD_SET(syslogPipe[0], &rfds);
timeout.tv_sec = 1;
timeout.tv_usec = 0;
rc = select(syslogPipe[0] + 1, &rfds, NULL, NULL, &timeout);
if (rc < 0)
{
if (errno != EINTR)
ereport(LOG,
(errcode_for_socket_access(),
errmsg("select() failed in logger process: %m")));
}
else if (rc > 0 && FD_ISSET(syslogPipe[0], &rfds))
{
bytesRead = piperead(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 once a second to
* check for 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);
pg_usleep(1000000L);
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("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);
}
}
}
/*
* Main entry point for syslogger process
* argc/argv parameters are valid only in EXEC_BACKEND case.
*/
NON_EXEC_STATIC void
SysLoggerMain(int argc, char *argv[])
{
#ifndef WIN32
char logbuffer[READ_BUF_SIZE];
int bytes_in_logbuffer = 0;
#endif
char *currentLogDir;
char *currentLogFilename;
int currentLogRotationAge;
pg_time_t now;
IsUnderPostmaster = true; /* we are a postmaster subprocess now */
MyProcPid = getpid(); /* reset MyProcPid */
MyStartTime = time(NULL); /* set our start time in case we call elog */
now = MyStartTime;
#ifdef EXEC_BACKEND
syslogger_parseArgs(argc, argv);
#endif /* EXEC_BACKEND */
am_syslogger = true;
init_ps_display("logger process", "", "", "");
/*
* 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.
*/
close(fileno(stdout));
close(fileno(stderr));
if (fd != -1)
{
dup2(fd, fileno(stdout));
dup2(fd, fileno(stderr));
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(_fileno(stderr), _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
/*
* If possible, make this process a group leader, so that the postmaster
* can signal any child processes too. (syslogger probably never has any
* child processes, but for consistency we make all postmaster child
* processes do this.)
*/
#ifdef HAVE_SETSID
if (setsid() < 0)
elog(FATAL, "setsid() failed: %m");
#endif
InitializeLatchSupport(); /* needed for latch waits */
/* Initialize private latch for use by signal handlers */
InitLatch(&sysLoggerLatch);
/*
* 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, sigHupHandler); /* 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);
pqsignal(SIGTTIN, SIG_DFL);
pqsignal(SIGTTOU, SIG_DFL);
pqsignal(SIGCONT, SIG_DFL);
pqsignal(SIGWINCH, SIG_DFL);
PG_SETMASK(&UnBlockSig);
#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 logfile's name. We recompute this 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_file_name = logfile_getname(first_syslogger_file_time, NULL);
/* remember active logfile parameters */
currentLogDir = pstrdup(Log_directory);
currentLogFilename = pstrdup(Log_filename);
currentLogRotationAge = Log_RotationAge;
/* set next planned rotation time */
set_next_rotation_time();
/* main worker loop */
for (;;)
{
bool time_based_rotation = false;
int size_rotation_for = 0;
long cur_timeout;
int cur_flags;
#ifndef WIN32
int rc;
#endif
/* Clear any already-pending wakeups */
ResetLatch(&sysLoggerLatch);
/*
* Process any requests or signals received recently.
*/
if (got_SIGHUP)
{
got_SIGHUP = 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
*/
mkdir(Log_directory, S_IRWXU);
}
if (strcmp(Log_filename, currentLogFilename) != 0)
{
pfree(currentLogFilename);
currentLogFilename = pstrdup(Log_filename);
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;
}
}
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 (rotation_requested)
{
/*
* Force rotation when both values are zero. It means the request
* was sent by pg_rotate_logfile.
*/
if (!time_based_rotation && size_rotation_for == 0)
size_rotation_for = LOG_DESTINATION_STDERR | LOG_DESTINATION_CSVLOG;
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;
cur_flags = WL_TIMEOUT;
}
else
{
cur_timeout = -1L;
cur_flags = 0;
}
/*
* Sleep until there's something to do
*/
#ifndef WIN32
rc = WaitLatchOrSocket(&sysLoggerLatch,
WL_LATCH_SET | WL_SOCKET_READABLE | cur_flags,
syslogPipe[0],
cur_timeout);
if (rc & 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) WaitLatch(&sysLoggerLatch,
WL_LATCH_SET | cur_flags,
cur_timeout);
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("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);
}
}
}
/*
* Main entry point for syslogger process
* argc/argv parameters are valid only in EXEC_BACKEND case.
*/
NON_EXEC_STATIC void
SysLoggerMain(int argc, char *argv[])
{
char *currentLogDir;
char *currentLogFilename;
int currentLogRotationAge;
IsUnderPostmaster = true; /* we are a postmaster subprocess now */
MyProcPid = getpid(); /* reset MyProcPid */
/* Lose the postmaster's on-exit routines */
on_exit_reset();
#ifdef EXEC_BACKEND
syslogger_parseArgs(argc, argv);
#endif /* EXEC_BACKEND */
am_syslogger = true;
init_ps_display("logger process", "", "");
set_ps_display("");
/*
* 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(NULL_DEV, O_WRONLY);
/*
* 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.
*/
close(fileno(stdout));
close(fileno(stderr));
dup2(fd, fileno(stdout));
dup2(fd, fileno(stderr));
close(fd);
}
/*
* 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, sigHupHandler); /* 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, SIG_IGN);
pqsignal(SIGUSR2, SIG_IGN);
/*
* Reset some signals that are accepted by postmaster but not here
*/
pqsignal(SIGCHLD, SIG_DFL);
pqsignal(SIGTTIN, SIG_DFL);
pqsignal(SIGTTOU, SIG_DFL);
pqsignal(SIGCONT, SIG_DFL);
pqsignal(SIGWINCH, SIG_DFL);
PG_SETMASK(&UnBlockSig);
#ifdef WIN32
/* Fire up separate data transfer thread */
InitializeCriticalSection(&sysfileSection);
{
unsigned int tid;
threadHandle = (HANDLE) _beginthreadex(0, 0, pipeThread, 0, 0, &tid);
}
#endif /* WIN32 */
/* remember active logfile parameters */
currentLogDir = pstrdup(Log_directory);
currentLogFilename = pstrdup(Log_filename);
currentLogRotationAge = Log_RotationAge;
/* set next planned rotation time */
set_next_rotation_time();
/* main worker loop */
for (;;)
{
bool rotation_requested = false;
bool time_based_rotation = false;
#ifndef WIN32
char logbuffer[1024];
int bytesRead;
int rc;
fd_set rfds;
struct timeval timeout;
#endif
if (got_SIGHUP)
{
got_SIGHUP = 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;
}
if (strcmp(Log_filename, currentLogFilename) != 0)
{
pfree(currentLogFilename);
currentLogFilename = pstrdup(Log_filename);
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 (!rotation_requested && Log_RotationAge > 0)
{
/* Do a logfile rotation if it's time */
pg_time_t now = time(NULL);
if (now >= next_rotation_time)
rotation_requested = time_based_rotation = true;
}
if (!rotation_requested && Log_RotationSize > 0)
{
/* Do a rotation if file is too big */
if (ftell(syslogFile) >= Log_RotationSize * 1024L)
rotation_requested = true;
}
if (rotation_requested)
logfile_rotate(time_based_rotation);
#ifndef WIN32
/*
* Wait for some data, timing out after 1 second
*/
FD_ZERO(&rfds);
FD_SET(syslogPipe[0], &rfds);
timeout.tv_sec = 1;
timeout.tv_usec = 0;
rc = select(syslogPipe[0] + 1, &rfds, NULL, NULL, &timeout);
if (rc < 0)
{
if (errno != EINTR)
ereport(LOG,
(errcode_for_socket_access(),
errmsg("select() failed in logger process: %m")));
}
else if (rc > 0 && FD_ISSET(syslogPipe[0], &rfds))
{
bytesRead = piperead(syslogPipe[0],
logbuffer, sizeof(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)
{
write_syslogger_file_binary(logbuffer, bytesRead);
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;
}
}
#else /* WIN32 */
/*
* On Windows we leave it to a separate thread to transfer data
* and detect pipe EOF. The main thread just wakes up once a
* second to check for SIGHUP and rotation conditions.
*/
pgwin32_backend_usleep(1000000);
#endif /* WIN32 */
if (pipe_eof_seen)
{
ereport(LOG,
(errmsg("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);
}
}
}
