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Diffstat (limited to 'src/backend/postmaster/syslogger.c')
| -rw-r--r-- | src/backend/postmaster/syslogger.c | 1566 |
1 files changed, 1566 insertions, 0 deletions
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c new file mode 100644 index 0000000..cad43bd --- /dev/null +++ b/src/backend/postmaster/syslogger.c @@ -0,0 +1,1566 @@ +/*------------------------------------------------------------------------- + * + * 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 <pgadmin@pse-consulting.de> + * + * Copyright (c) 2004-2021, PostgreSQL Global Development Group + * + * + * IDENTIFICATION + * src/backend/postmaster/syslogger.c + * + *------------------------------------------------------------------------- + */ +#include "postgres.h" + +#include <fcntl.h> +#include <limits.h> +#include <signal.h> +#include <time.h> +#include <unistd.h> +#include <sys/stat.h> +#include <sys/time.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 "postmaster/fork_process.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/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) + +/* Log rotation signal file path, relative to $PGDATA */ +#define LOGROTATE_SIGNAL_FILE "logrotate" + + +/* + * 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; + +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 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 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; + WaitEventSet *wes; + + now = MyStartTime; + +#ifdef EXEC_BACKEND + syslogger_parseArgs(argc, argv); +#endif /* EXEC_BACKEND */ + + 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(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, 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); + + 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; + + /* + * 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(CurrentMemoryContext, 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; + + /* + * 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() or "pg_ctl logrotate". + */ + 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; + } + 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); + } + } +} + +/* + * 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. + * + * 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); + } + +#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 MyBackendType is B_LOGGER. + * 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. The file is opened with the same permissions as what gets + * created in the data directory and has proper buffering options. + */ +static void +update_metainfo_datafile(void) +{ + FILE *fh; + mode_t oumask; + + 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; + } + + /* 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_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 + * -------------------------------- + */ + +/* + * Check to see if a log rotation request has arrived. Should be + * called by postmaster after receiving SIGUSR1. + */ +bool +CheckLogrotateSignal(void) +{ + struct stat stat_buf; + + if (stat(LOGROTATE_SIGNAL_FILE, &stat_buf) == 0) + return true; + + return false; +} + +/* + * Remove the file signaling a log rotation request. + */ +void +RemoveLogrotateSignalFiles(void) +{ + unlink(LOGROTATE_SIGNAL_FILE); +} + +/* SIGUSR1: set flag to rotate logfile */ +static void +sigUsr1Handler(SIGNAL_ARGS) +{ + int save_errno = errno; + + rotation_requested = true; + SetLatch(MyLatch); + + errno = save_errno; +} |