/*------------------------------------------------------------------------- * * syslogger.c * * The system logger (syslogger) appeared in Postgres 8.0. It catches all * stderr output from the postmaster, backends, and other subprocesses * by redirecting to a pipe, and writes it to a set of logfiles. * It's possible to have size and age limits for the logfile configured * in postgresql.conf. If these limits are reached or passed, the * current logfile is closed and a new one is created (rotated). * The logfiles are stored in a subdirectory (configurable in * postgresql.conf), using a user-selectable naming scheme. * * Author: Andreas Pflug * * Copyright (c) 2004-2018, PostgreSQL Global Development Group * * * IDENTIFICATION * src/backend/postmaster/syslogger.c * *------------------------------------------------------------------------- */ #include "postgres.h" #include #include #include #include #include #include #include #include "lib/stringinfo.h" #include "libpq/pqsignal.h" #include "miscadmin.h" #include "nodes/pg_list.h" #include "pgstat.h" #include "pgtime.h" #include "postmaster/fork_process.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/ps_status.h" #include "utils/timestamp.h" /* * We read() into a temp buffer twice as big as a chunk, so that any fragment * left after processing can be moved down to the front and we'll still have * room to read a full chunk. */ #define READ_BUF_SIZE (2 * PIPE_CHUNK_SIZE) /* * GUC parameters. Logging_collector cannot be changed after postmaster * start, but the rest can change at SIGHUP. */ 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; /* * Globally visible state (used by elog.c) */ bool am_syslogger = false; extern bool redirection_done; /* * Private state */ 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; NON_EXEC_STATIC pg_time_t first_syslogger_file_time = 0; static char *last_file_name = NULL; static char *last_csv_file_name = NULL; /* * Buffers for saving partial messages from different backends. * * Keep NBUFFER_LISTS lists of these, with the entry for a given source pid * being in the list numbered (pid % NBUFFER_LISTS), so as to cut down on * the number of entries we have to examine for any one incoming message. * There must never be more than one entry for the same source pid. * * An inactive buffer is not removed from its list, just held for re-use. * An inactive buffer has pid == 0 and undefined contents of data. */ typedef struct { int32 pid; /* PID of source process */ StringInfoData data; /* accumulated data, as a StringInfo */ } save_buffer; #define NBUFFER_LISTS 256 static List *buffer_lists[NBUFFER_LISTS]; /* These must be exported for EXEC_BACKEND case ... annoying */ #ifndef WIN32 int syslogPipe[2] = {-1, -1}; #else HANDLE syslogPipe[2] = {0, 0}; #endif #ifdef WIN32 static HANDLE threadHandle = 0; static CRITICAL_SECTION sysloggerSection; #endif /* * Flags set by interrupt handlers for later service in the main loop. */ static volatile sig_atomic_t got_SIGHUP = false; static volatile sig_atomic_t rotation_requested = false; /* Local subroutines */ #ifdef EXEC_BACKEND static pid_t syslogger_forkexec(void); static void syslogger_parseArgs(int argc, char *argv[]); #endif NON_EXEC_STATIC void SysLoggerMain(int argc, char *argv[]) pg_attribute_noreturn(); 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); #ifdef WIN32 static unsigned int __stdcall pipeThread(void *arg); #endif static void logfile_rotate(bool time_based_rotation, int size_rotation_for); static char *logfile_getname(pg_time_t timestamp, const char *suffix); static void set_next_rotation_time(void); static void sigHupHandler(SIGNAL_ARGS); static void sigUsr1Handler(SIGNAL_ARGS); static void update_metainfo_datafile(void); /* * 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; now = MyStartTime; #ifdef EXEC_BACKEND syslogger_parseArgs(argc, argv); #endif /* EXEC_BACKEND */ am_syslogger = true; init_ps_display("logger", "", "", ""); /* * 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(fileno(stdout)); close(fileno(stderr)); if (fd != -1) { (void) dup2(fd, fileno(stdout)); (void) 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 /* * 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 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_file_name = logfile_getname(first_syslogger_file_time, NULL); if (csvlogFile != NULL) last_csv_file_name = logfile_getname(first_syslogger_file_time, ".csv"); /* 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; /* 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(MyLatch); /* * 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 */ (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; /* * 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 (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(MyLatch, WL_LATCH_SET | WL_SOCKET_READABLE | cur_flags, syslogPipe[0], cur_timeout, WAIT_EVENT_SYSLOGGER_MAIN); 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(MyLatch, WL_LATCH_SET | cur_flags, cur_timeout, 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("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); } } } /* * Postmaster subroutine to start a syslogger subprocess. */ int SysLogger_Start(void) { 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. */ #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); } #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], fileno(stdout)) < 0) ereport(FATAL, (errcode_for_file_access(), errmsg("could not redirect stdout: %m"))); fflush(stderr); if (dup2(syslogPipe[1], fileno(stderr)) < 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, _fileno(stderr)) < 0) ereport(FATAL, (errcode_for_file_access(), errmsg("could not redirect stderr: %m"))); close(fd); _setmode(_fileno(stderr), _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; } return (int) sysloggerPid; } /* we should never reach here */ return 0; } #ifdef EXEC_BACKEND /* * syslogger_forkexec() - * * Format up the arglist for, then fork and exec, a syslogger process */ static pid_t syslogger_forkexec(void) { char *av[10]; int ac = 0; char filenobuf[32]; char csvfilenobuf[32]; av[ac++] = "postgres"; av[ac++] = "--forklog"; av[ac++] = NULL; /* filled in by postmaster_forkexec */ /* static variables (those not passed by write_backend_variables) */ #ifndef WIN32 if (syslogFile != NULL) snprintf(filenobuf, sizeof(filenobuf), "%d", fileno(syslogFile)); else strcpy(filenobuf, "-1"); #else /* WIN32 */ if (syslogFile != NULL) snprintf(filenobuf, sizeof(filenobuf), "%ld", (long) _get_osfhandle(_fileno(syslogFile))); else strcpy(filenobuf, "0"); #endif /* WIN32 */ av[ac++] = filenobuf; #ifndef WIN32 if (csvlogFile != NULL) snprintf(csvfilenobuf, sizeof(csvfilenobuf), "%d", fileno(csvlogFile)); else strcpy(csvfilenobuf, "-1"); #else /* WIN32 */ if (csvlogFile != NULL) snprintf(csvfilenobuf, sizeof(csvfilenobuf), "%ld", (long) _get_osfhandle(_fileno(csvlogFile))); else strcpy(csvfilenobuf, "0"); #endif /* WIN32 */ av[ac++] = csvfilenobuf; av[ac] = NULL; Assert(ac < lengthof(av)); return postmaster_forkexec(ac, av); } /* * syslogger_parseArgs() - * * Extract data from the arglist for exec'ed syslogger process */ static void syslogger_parseArgs(int argc, char *argv[]) { int fd; Assert(argc == 5); argv += 3; /* * 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... */ #ifndef WIN32 fd = atoi(*argv++); if (fd != -1) { syslogFile = fdopen(fd, "a"); setvbuf(syslogFile, NULL, PG_IOLBF, 0); } fd = atoi(*argv++); if (fd != -1) { csvlogFile = fdopen(fd, "a"); setvbuf(csvlogFile, NULL, PG_IOLBF, 0); } #else /* WIN32 */ fd = atoi(*argv++); if (fd != 0) { fd = _open_osfhandle(fd, _O_APPEND | _O_TEXT); if (fd > 0) { syslogFile = fdopen(fd, "a"); setvbuf(syslogFile, NULL, PG_IOLBF, 0); } } fd = atoi(*argv++); if (fd != 0) { fd = _open_osfhandle(fd, _O_APPEND | _O_TEXT); if (fd > 0) { csvlogFile = fdopen(fd, "a"); setvbuf(csvlogFile, NULL, PG_IOLBF, 0); } } #endif /* WIN32 */ } #endif /* EXEC_BACKEND */ /* -------------------------------- * pipe protocol handling * -------------------------------- */ /* * Process data received through the syslogger pipe. * * This routine interprets the log pipe protocol which sends log messages as * (hopefully atomic) chunks - such chunks are detected and reassembled here. * * The protocol has a header that starts with two nul bytes, then has a 16 bit * length, the pid of the sending process, and a flag to indicate if it is * the last chunk in a message. Incomplete chunks are saved until we read some * more, and non-final chunks are accumulated until we get the final chunk. * * All of this is to avoid 2 problems: * . partial messages being written to logfiles (messes rotation), and * . messages from different backends being interleaved (messages garbled). * * Any non-protocol messages are written out directly. These should only come * from non-PostgreSQL sources, however (e.g. third party libraries writing to * stderr). * * logbuffer is the data input buffer, and *bytes_in_logbuffer is the number * of bytes present. On exit, any not-yet-eaten data is left-justified in * logbuffer, and *bytes_in_logbuffer is updated. */ static void process_pipe_input(char *logbuffer, int *bytes_in_logbuffer) { 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; /* Do we have a valid header? */ memcpy(&p, cursor, offsetof(PipeProtoHeader, data)); if (p.nuls[0] == '\0' && p.nuls[1] == '\0' && p.len > 0 && p.len <= PIPE_MAX_PAYLOAD && p.pid != 0 && (p.is_last == 't' || p.is_last == 'f' || p.is_last == 'T' || p.is_last == 'F')) { 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; dest = (p.is_last == 'T' || p.is_last == 'F') ? LOG_DESTINATION_CSVLOG : LOG_DESTINATION_STDERR; /* 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.is_last == 'f' || p.is_last == 'F') { /* * 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; } /* * Force out any buffered data * * This is currently used only at syslogger shutdown, but could perhaps be * useful at other times, so it is careful to leave things in a clean state. */ static void flush_pipe_input(char *logbuffer, int *bytes_in_logbuffer) { 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; } /* -------------------------------- * logfile routines * -------------------------------- */ /* * Write text to the currently open logfile * * This is exported so that elog.c can call it when am_syslogger is true. * This allows the syslogger process to record elog messages of its own, * even though its stderr does not point at the syslog pipe. */ void write_syslogger_file(const char *buffer, int count, int destination) { int rc; FILE *logfile; /* * If we're told to write to csvlogFile, but it's not open, dump the data * to syslogFile (which is always open) instead. This can happen if CSV * output is enabled after postmaster start and we've been unable to open * csvlogFile. There are also race conditions during a parameter change * whereby backends might send us CSV output before we open csvlogFile or * after we close it. Writing CSV-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 csvlogFile on-the-fly. Any * failure in that would lead to recursion. */ logfile = (destination == LOG_DESTINATION_CSVLOG && csvlogFile != NULL) ? csvlogFile : 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)); } #ifdef WIN32 /* * Worker thread to transfer data from the pipe to the current logfile. * * We need this because on Windows, WaitforMultipleObjects does not work on * unnamed pipes: it always reports "signaled", so the blocking ReadFile won't * allow for SIGHUP; and select is for sockets only. */ static unsigned int __stdcall pipeThread(void *arg) { char logbuffer[READ_BUF_SIZE]; int bytes_in_logbuffer = 0; for (;;) { DWORD bytesRead; BOOL result; result = ReadFile(syslogPipe[0], logbuffer + bytes_in_logbuffer, sizeof(logbuffer) - bytes_in_logbuffer, &bytesRead, 0); /* * Enter critical section before doing anything that might touch * global state shared by the main thread. Anything that uses * palloc()/pfree() in particular are not safe outside the critical * section. */ EnterCriticalSection(&sysloggerSection); if (!result) { DWORD error = GetLastError(); if (error == ERROR_HANDLE_EOF || error == ERROR_BROKEN_PIPE) break; _dosmaperr(error); ereport(LOG, (errcode_for_file_access(), errmsg("could not read from logger pipe: %m"))); } else if (bytesRead > 0) { bytes_in_logbuffer += bytesRead; process_pipe_input(logbuffer, &bytes_in_logbuffer); } /* * If we've filled the current logfile, nudge the main thread to do a * log rotation. */ if (Log_RotationSize > 0) { if (ftell(syslogFile) >= Log_RotationSize * 1024L || (csvlogFile != NULL && ftell(csvlogFile) >= Log_RotationSize * 1024L)) SetLatch(MyLatch); } LeaveCriticalSection(&sysloggerSection); } /* We exit the above loop only upon detecting pipe EOF */ pipe_eof_seen = true; /* if there's any data left then force it out now */ flush_pipe_input(logbuffer, &bytes_in_logbuffer); /* set the latch to waken the main thread, which will quit */ SetLatch(MyLatch); LeaveCriticalSection(&sysloggerSection); _endthread(); return 0; } #endif /* WIN32 */ /* * Open a new logfile with proper permissions and buffering options. * * If allow_errors is true, we just log any open failure and return NULL * (with errno still correct for the fopen failure). * Otherwise, errors are treated as fatal. */ static FILE * logfile_open(const char *filename, const char *mode, bool allow_errors) { 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; } /* * perform logfile rotation */ static void logfile_rotate(bool time_based_rotation, int size_rotation_for) { char *filename; char *csvfilename = NULL; pg_time_t fntime; FILE *fh; 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); filename = logfile_getname(fntime, NULL); if (Log_destination & LOG_DESTINATION_CSVLOG) csvfilename = logfile_getname(fntime, ".csv"); /* * 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. * * Note: last_file_name should never be NULL here, but if it is, append. */ if (time_based_rotation || (size_rotation_for & LOG_DESTINATION_STDERR)) { 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); if (csvfilename) pfree(csvfilename); return; } fclose(syslogFile); syslogFile = fh; /* instead of pfree'ing filename, remember it for next time */ if (last_file_name != NULL) pfree(last_file_name); last_file_name = filename; filename = NULL; } /* * Same as above, but for csv file. Note that if LOG_DESTINATION_CSVLOG * was just turned on, we might have to open csvlogFile here though it was * not open before. In such a case we'll append not overwrite (since * last_csv_file_name will be NULL); that is consistent with the normal * rules since it's not a time-based rotation. */ if ((Log_destination & LOG_DESTINATION_CSVLOG) && (csvlogFile == NULL || time_based_rotation || (size_rotation_for & LOG_DESTINATION_CSVLOG))) { if (Log_truncate_on_rotation && time_based_rotation && last_csv_file_name != NULL && strcmp(csvfilename, last_csv_file_name) != 0) fh = logfile_open(csvfilename, "w", true); else fh = logfile_open(csvfilename, "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); if (csvfilename) pfree(csvfilename); return; } if (csvlogFile != NULL) fclose(csvlogFile); csvlogFile = fh; /* instead of pfree'ing filename, remember it for next time */ if (last_csv_file_name != NULL) pfree(last_csv_file_name); last_csv_file_name = csvfilename; csvfilename = NULL; } else if (!(Log_destination & LOG_DESTINATION_CSVLOG) && csvlogFile != NULL) { /* CSVLOG was just turned off, so close the old file */ fclose(csvlogFile); csvlogFile = NULL; if (last_csv_file_name != NULL) pfree(last_csv_file_name); last_csv_file_name = NULL; } if (filename) pfree(filename); if (csvfilename) pfree(csvfilename); update_metainfo_datafile(); set_next_rotation_time(); } /* * construct logfile name using timestamp information * * If suffix isn't NULL, append it to the name, replacing any ".log" * that may be in the pattern. * * Result is palloc'd. */ static char * logfile_getname(pg_time_t timestamp, const char *suffix) { 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(×tamp, 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; } /* * Determine the next planned rotation time, and store in next_rotation_time. */ static void set_next_rotation_time(void) { 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; } /* * Store the name of the file(s) where the log collector, when enabled, writes * log messages. Useful for finding the name(s) of the current log file(s) * when there is time-based logfile rotation. Filenames are stored in a * temporary file and which is renamed into the final destination for * atomicity. */ static void update_metainfo_datafile(void) { FILE *fh; if (!(Log_destination & LOG_DESTINATION_STDERR) && !(Log_destination & LOG_DESTINATION_CSVLOG)) { 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; } if ((fh = logfile_open(LOG_METAINFO_DATAFILE_TMP, "w", true)) == NULL) { ereport(LOG, (errcode_for_file_access(), errmsg("could not open file \"%s\": %m", LOG_METAINFO_DATAFILE_TMP))); return; } if (last_file_name && (Log_destination & LOG_DESTINATION_STDERR)) { if (fprintf(fh, "stderr %s\n", last_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; } } 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))); } /* -------------------------------- * signal handler routines * -------------------------------- */ /* SIGHUP: set flag to reload config file */ static void sigHupHandler(SIGNAL_ARGS) { int save_errno = errno; got_SIGHUP = true; SetLatch(MyLatch); errno = save_errno; } /* SIGUSR1: set flag to rotate logfile */ static void sigUsr1Handler(SIGNAL_ARGS) { int save_errno = errno; rotation_requested = true; SetLatch(MyLatch); errno = save_errno; }