diff options
| -rwxr-xr-x | configure | 2 | ||||
| -rw-r--r-- | configure.in | 2 | ||||
| -rw-r--r-- | src/backend/storage/ipc/latch.c | 6 | ||||
| -rw-r--r-- | src/backend/storage/ipc/pmsignal.c | 125 | ||||
| -rw-r--r-- | src/backend/utils/init/miscinit.c | 4 | ||||
| -rw-r--r-- | src/include/pg_config.h.in | 3 | ||||
| -rw-r--r-- | src/include/pg_config.h.win32 | 3 | ||||
| -rw-r--r-- | src/include/storage/pmsignal.h | 33 |
8 files changed, 159 insertions, 19 deletions
diff --git a/configure b/configure index 1bc465b9429..41e0e1cf34a 100755 --- a/configure +++ b/configure @@ -12494,7 +12494,7 @@ $as_echo "#define HAVE_STDBOOL_H 1" >>confdefs.h fi -for ac_header in atomic.h crypt.h dld.h fp_class.h getopt.h ieeefp.h ifaddrs.h langinfo.h mbarrier.h poll.h sys/epoll.h sys/ipc.h sys/pstat.h sys/resource.h sys/select.h sys/sem.h sys/shm.h sys/sockio.h sys/tas.h sys/un.h termios.h ucred.h utime.h wchar.h wctype.h +for ac_header in atomic.h crypt.h dld.h fp_class.h getopt.h ieeefp.h ifaddrs.h langinfo.h mbarrier.h poll.h sys/epoll.h sys/ipc.h sys/prctl.h sys/pstat.h sys/resource.h sys/select.h sys/sem.h sys/shm.h sys/sockio.h sys/tas.h sys/un.h termios.h ucred.h utime.h wchar.h wctype.h do : as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh` ac_fn_c_check_header_mongrel "$LINENO" "$ac_header" "$as_ac_Header" "$ac_includes_default" diff --git a/configure.in b/configure.in index a6b3b88cfab..1e76c9ee46b 100644 --- a/configure.in +++ b/configure.in @@ -1260,7 +1260,7 @@ AC_SUBST(UUID_LIBS) AC_HEADER_STDBOOL -AC_CHECK_HEADERS([atomic.h crypt.h dld.h fp_class.h getopt.h ieeefp.h ifaddrs.h langinfo.h mbarrier.h poll.h sys/epoll.h sys/ipc.h sys/pstat.h sys/resource.h sys/select.h sys/sem.h sys/shm.h sys/sockio.h sys/tas.h sys/un.h termios.h ucred.h utime.h wchar.h wctype.h]) +AC_CHECK_HEADERS([atomic.h crypt.h dld.h fp_class.h getopt.h ieeefp.h ifaddrs.h langinfo.h mbarrier.h poll.h sys/epoll.h sys/ipc.h sys/prctl.h sys/pstat.h sys/resource.h sys/select.h sys/sem.h sys/shm.h sys/sockio.h sys/tas.h sys/un.h termios.h ucred.h utime.h wchar.h wctype.h]) # On BSD, test for net/if.h will fail unless sys/socket.h # is included first. diff --git a/src/backend/storage/ipc/latch.c b/src/backend/storage/ipc/latch.c index e6706f7fb80..f6dda9cc9ac 100644 --- a/src/backend/storage/ipc/latch.c +++ b/src/backend/storage/ipc/latch.c @@ -1112,7 +1112,7 @@ WaitEventSetWaitBlock(WaitEventSet *set, int cur_timeout, * WL_POSTMASTER_DEATH event would be painful. Re-checking doesn't * cost much. */ - if (!PostmasterIsAlive()) + if (!PostmasterIsAliveInternal()) { occurred_events->fd = PGINVALID_SOCKET; occurred_events->events = WL_POSTMASTER_DEATH; @@ -1230,7 +1230,7 @@ WaitEventSetWaitBlock(WaitEventSet *set, int cur_timeout, * WL_POSTMASTER_DEATH event would be painful. Re-checking doesn't * cost much. */ - if (!PostmasterIsAlive()) + if (!PostmasterIsAliveInternal()) { occurred_events->fd = PGINVALID_SOCKET; occurred_events->events = WL_POSTMASTER_DEATH; @@ -1390,7 +1390,7 @@ WaitEventSetWaitBlock(WaitEventSet *set, int cur_timeout, * even though there is no known reason to think that the event could * be falsely set on Windows. */ - if (!PostmasterIsAlive()) + if (!PostmasterIsAliveInternal()) { occurred_events->fd = PGINVALID_SOCKET; occurred_events->events = WL_POSTMASTER_DEATH; diff --git a/src/backend/storage/ipc/pmsignal.c b/src/backend/storage/ipc/pmsignal.c index be61858fc67..ebf027306f7 100644 --- a/src/backend/storage/ipc/pmsignal.c +++ b/src/backend/storage/ipc/pmsignal.c @@ -17,6 +17,10 @@ #include <signal.h> #include <unistd.h> +#ifdef HAVE_SYS_PRCTL_H +#include <sys/prctl.h> +#endif + #include "miscadmin.h" #include "postmaster/postmaster.h" #include "replication/walsender.h" @@ -71,6 +75,35 @@ struct PMSignalData NON_EXEC_STATIC volatile PMSignalData *PMSignalState = NULL; +/* + * Signal handler to be notified if postmaster dies. + */ +#ifdef USE_POSTMASTER_DEATH_SIGNAL +volatile sig_atomic_t postmaster_possibly_dead = false; + +static void +postmaster_death_handler(int signo) +{ + postmaster_possibly_dead = true; +} + +/* + * The available signals depend on the OS. SIGUSR1 and SIGUSR2 are already + * used for other things, so choose another one. + * + * Currently, we assume that we can always find a signal to use. That + * seems like a reasonable assumption for all platforms that are modern + * enough to have a parent-death signaling mechanism. + */ +#if defined(SIGINFO) +#define POSTMASTER_DEATH_SIGNAL SIGINFO +#elif defined(SIGPWR) +#define POSTMASTER_DEATH_SIGNAL SIGPWR +#else +#error "cannot find a signal to use for postmaster death" +#endif + +#endif /* USE_POSTMASTER_DEATH_SIGNAL */ /* * PMSignalShmemSize @@ -266,28 +299,94 @@ MarkPostmasterChildInactive(void) /* - * PostmasterIsAlive - check whether postmaster process is still alive + * PostmasterIsAliveInternal - check whether postmaster process is still alive + * + * This is the slow path of PostmasterIsAlive(), where the caller has already + * checked 'postmaster_possibly_dead'. (On platforms that don't support + * a signal for parent death, PostmasterIsAlive() is just an alias for this.) */ bool -PostmasterIsAlive(void) +PostmasterIsAliveInternal(void) { -#ifndef WIN32 - char c; - ssize_t rc; +#ifdef USE_POSTMASTER_DEATH_SIGNAL + /* + * Reset the flag before checking, so that we don't miss a signal if + * postmaster dies right after the check. If postmaster was indeed dead, + * we'll re-arm it before returning to caller. + */ + postmaster_possibly_dead = false; +#endif - rc = read(postmaster_alive_fds[POSTMASTER_FD_WATCH], &c, 1); - if (rc < 0) +#ifndef WIN32 { - if (errno == EAGAIN || errno == EWOULDBLOCK) + char c; + ssize_t rc; + + rc = read(postmaster_alive_fds[POSTMASTER_FD_WATCH], &c, 1); + + /* + * In the usual case, the postmaster is still alive, and there is no + * data in the pipe. + */ + if (rc < 0 && (errno == EAGAIN || errno == EWOULDBLOCK)) return true; else - elog(FATAL, "read on postmaster death monitoring pipe failed: %m"); + { + /* + * Postmaster is dead, or something went wrong with the read() + * call. + */ + +#ifdef USE_POSTMASTER_DEATH_SIGNAL + postmaster_possibly_dead = true; +#endif + + if (rc < 0) + elog(FATAL, "read on postmaster death monitoring pipe failed: %m"); + else if (rc > 0) + elog(FATAL, "unexpected data in postmaster death monitoring pipe"); + + return false; + } } - else if (rc > 0) - elog(FATAL, "unexpected data in postmaster death monitoring pipe"); - return false; #else /* WIN32 */ - return (WaitForSingleObject(PostmasterHandle, 0) == WAIT_TIMEOUT); + if (WaitForSingleObject(PostmasterHandle, 0) == WAIT_TIMEOUT) + return true; + else + { +#ifdef USE_POSTMASTER_DEATH_SIGNAL + postmaster_possibly_dead = true; +#endif + return false; + } #endif /* WIN32 */ } + +/* + * PostmasterDeathSignalInit - request signal on postmaster death if possible + */ +void +PostmasterDeathSignalInit(void) +{ +#ifdef USE_POSTMASTER_DEATH_SIGNAL + int signum = POSTMASTER_DEATH_SIGNAL; + + /* Register our signal handler. */ + pqsignal(signum, postmaster_death_handler); + + /* Request a signal on parent exit. */ +#if defined(PR_SET_PDEATHSIG) + if (prctl(PR_SET_PDEATHSIG, signum) < 0) + elog(ERROR, "could not request parent death signal: %m"); +#else +#error "USE_POSTMASTER_DEATH_SIGNAL set, but there is no mechanism to request the signal" +#endif + + /* + * Just in case the parent was gone already and we missed it, we'd better + * check the slow way on the first call. + */ + postmaster_possibly_dead = true; +#endif /* USE_POSTMASTER_DEATH_SIGNAL */ +} diff --git a/src/backend/utils/init/miscinit.c b/src/backend/utils/init/miscinit.c index 03b28c3604a..4bb28938c27 100644 --- a/src/backend/utils/init/miscinit.c +++ b/src/backend/utils/init/miscinit.c @@ -43,6 +43,7 @@ #include "storage/ipc.h" #include "storage/latch.h" #include "storage/pg_shmem.h" +#include "storage/pmsignal.h" #include "storage/proc.h" #include "storage/procarray.h" #include "utils/builtins.h" @@ -304,6 +305,9 @@ InitPostmasterChild(void) if (setsid() < 0) elog(FATAL, "setsid() failed: %m"); #endif + + /* Request a signal if the postmaster dies, if possible. */ + PostmasterDeathSignalInit(); } /* diff --git a/src/include/pg_config.h.in b/src/include/pg_config.h.in index dcb25bb7234..4ef53416785 100644 --- a/src/include/pg_config.h.in +++ b/src/include/pg_config.h.in @@ -600,6 +600,9 @@ /* Define to 1 if you have the <sys/ipc.h> header file. */ #undef HAVE_SYS_IPC_H +/* Define to 1 if you have the <sys/prctl.h> header file. */ +#undef HAVE_SYS_PRCTL_H + /* Define to 1 if you have the <sys/pstat.h> header file. */ #undef HAVE_SYS_PSTAT_H diff --git a/src/include/pg_config.h.win32 b/src/include/pg_config.h.win32 index 456b5c6b66d..01cf8daf438 100644 --- a/src/include/pg_config.h.win32 +++ b/src/include/pg_config.h.win32 @@ -482,6 +482,9 @@ /* Define to 1 if you have the <sys/ipc.h> header file. */ /* #undef HAVE_SYS_IPC_H */ +/* Define to 1 if you have the <sys/prctl.h> header file. */ +/* #undef HAVE_SYS_PRCTL_H */ + /* Define to 1 if you have the <sys/pstat.h> header file. */ /* #undef HAVE_SYS_PSTAT_H */ diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h index bec162cc16d..54e7108ac0b 100644 --- a/src/include/storage/pmsignal.h +++ b/src/include/storage/pmsignal.h @@ -14,6 +14,10 @@ #ifndef PMSIGNAL_H #define PMSIGNAL_H +#ifdef HAVE_SYS_PRCTL_H +#include "sys/prctl.h" +#endif + /* * Reasons for signaling the postmaster. We can cope with simultaneous * signals for different reasons. If the same reason is signaled multiple @@ -51,6 +55,33 @@ extern bool IsPostmasterChildWalSender(int slot); extern void MarkPostmasterChildActive(void); extern void MarkPostmasterChildInactive(void); extern void MarkPostmasterChildWalSender(void); -extern bool PostmasterIsAlive(void); +extern bool PostmasterIsAliveInternal(void); +extern void PostmasterDeathSignalInit(void); + + +/* + * Do we have a way to ask for a signal on parent death? + * + * If we do, pmsignal.c will set up a signal handler, that sets a flag when + * the parent dies. Checking the flag first makes PostmasterIsAlive() a lot + * cheaper in usual case that the postmaster is alive. + */ +#if defined(HAVE_SYS_PRCTL_H) && defined(PR_SET_PDEATHSIG) +#define USE_POSTMASTER_DEATH_SIGNAL +#endif + +#ifdef USE_POSTMASTER_DEATH_SIGNAL +extern volatile sig_atomic_t postmaster_possibly_dead; + +static inline bool +PostmasterIsAlive(void) +{ + if (likely(!postmaster_possibly_dead)) + return true; + return PostmasterIsAliveInternal(); +} +#else +#define PostmasterIsAlive() PostmasterIsAliveInternal() +#endif #endif /* PMSIGNAL_H */ |