diff options
Diffstat (limited to 'src/backend/postmaster/postmaster.c')
| -rw-r--r-- | src/backend/postmaster/postmaster.c | 106 |
1 files changed, 88 insertions, 18 deletions
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index bd0039e2626..dca5efc382f 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -368,6 +368,7 @@ static int CountChildren(int target); static bool CreateOptsFile(int argc, char *argv[], char *fullprogname); static pid_t StartChildProcess(AuxProcType type); static void StartAutovacuumWorker(void); +static void InitPostmasterDeathWatchHandle(void); #ifdef EXEC_BACKEND @@ -383,8 +384,6 @@ typedef struct HANDLE procHandle; DWORD procId; } win32_deadchild_waitinfo; - -HANDLE PostmasterHandle; #endif static pid_t backend_forkexec(Port *port); @@ -439,6 +438,7 @@ typedef struct HANDLE initial_signal_pipe; HANDLE syslogPipe[2]; #else + int postmaster_alive_fds[2]; int syslogPipe[2]; #endif char my_exec_path[MAXPGPATH]; @@ -469,6 +469,16 @@ static void ShmemBackendArrayRemove(Backend *bn); #define EXIT_STATUS_0(st) ((st) == 0) #define EXIT_STATUS_1(st) (WIFEXITED(st) && WEXITSTATUS(st) == 1) +#ifndef WIN32 +/* + * File descriptors for pipe used to monitor if postmaster is alive. + * First is POSTMASTER_FD_WATCH, second is POSTMASTER_FD_OWN. + */ +int postmaster_alive_fds[2] = { -1, -1 }; +#else +/* Process handle of postmaster used for the same purpose on Windows */ +HANDLE PostmasterHandle; +#endif /* * Postmaster main entry point @@ -962,8 +972,13 @@ PostmasterMain(int argc, char *argv[]) */ BackendList = DLNewList(); -#ifdef WIN32 + /* + * Initialize pipe (or process handle on Windows) that allows children to + * wake up from sleep on postmaster death. + */ + InitPostmasterDeathWatchHandle(); +#ifdef WIN32 /* * Initialize I/O completion port used to deliver list of dead children. */ @@ -971,21 +986,6 @@ PostmasterMain(int argc, char *argv[]) if (win32ChildQueue == NULL) ereport(FATAL, (errmsg("could not create I/O completion port for child queue"))); - - /* - * Set up a handle that child processes can use to check whether the - * postmaster is still running. - */ - if (DuplicateHandle(GetCurrentProcess(), - GetCurrentProcess(), - GetCurrentProcess(), - &PostmasterHandle, - 0, - TRUE, - DUPLICATE_SAME_ACCESS) == 0) - ereport(FATAL, - (errmsg_internal("could not duplicate postmaster handle: error code %d", - (int) GetLastError()))); #endif /* @@ -1965,6 +1965,19 @@ ClosePostmasterPorts(bool am_syslogger) { int i; +#ifndef WIN32 + /* + * Close the write end of postmaster death watch pipe. It's important to + * do this as early as possible, so that if postmaster dies, others won't + * think that it's still running because we're holding the pipe open. + */ + if (close(postmaster_alive_fds[POSTMASTER_FD_OWN])) + ereport(FATAL, + (errcode_for_file_access(), + errmsg_internal("could not close postmaster death monitoring pipe in child process: %m"))); + postmaster_alive_fds[POSTMASTER_FD_OWN] = -1; +#endif + /* Close the listen sockets */ for (i = 0; i < MAXLISTEN; i++) { @@ -4643,6 +4656,9 @@ save_backend_variables(BackendParameters *param, Port *port, pgwin32_create_signal_listener(childPid), childProcess)) return false; +#else + memcpy(¶m->postmaster_alive_fds, &postmaster_alive_fds, + sizeof(postmaster_alive_fds)); #endif memcpy(¶m->syslogPipe, &syslogPipe, sizeof(syslogPipe)); @@ -4858,6 +4874,9 @@ restore_backend_variables(BackendParameters *param, Port *port) #ifdef WIN32 PostmasterHandle = param->PostmasterHandle; pgwin32_initial_signal_pipe = param->initial_signal_pipe; +#else + memcpy(&postmaster_alive_fds, ¶m->postmaster_alive_fds, + sizeof(postmaster_alive_fds)); #endif memcpy(&syslogPipe, ¶m->syslogPipe, sizeof(syslogPipe)); @@ -4979,3 +4998,54 @@ pgwin32_deadchild_callback(PVOID lpParameter, BOOLEAN TimerOrWaitFired) } #endif /* WIN32 */ + +/* + * Initialize one and only handle for monitoring postmaster death. + * + * Called once in the postmaster, so that child processes can subsequently + * monitor if their parent is dead. + */ +static void +InitPostmasterDeathWatchHandle(void) +{ +#ifndef WIN32 + /* + * Create a pipe. Postmaster holds the write end of the pipe open + * (POSTMASTER_FD_OWN), and children hold the read end. Children can + * pass the read file descriptor to select() to wake up in case postmaster + * dies, or check for postmaster death with a (read() == 0). Children must + * close the write end as soon as possible after forking, because EOF + * won't be signaled in the read end until all processes have closed the + * write fd. That is taken care of in ClosePostmasterPorts(). + */ + Assert(MyProcPid == PostmasterPid); + if (pipe(postmaster_alive_fds)) + ereport(FATAL, + (errcode_for_file_access(), + errmsg_internal("could not create pipe to monitor postmaster death: %m"))); + + /* + * Set O_NONBLOCK to allow testing for the fd's presence with a read() + * call. + */ + if (fcntl(postmaster_alive_fds[POSTMASTER_FD_WATCH], F_SETFL, O_NONBLOCK)) + ereport(FATAL, + (errcode_for_socket_access(), + errmsg_internal("could not set postmaster death monitoring pipe to non-blocking mode: %m"))); + +#else + /* + * On Windows, we use a process handle for the same purpose. + */ + if (DuplicateHandle(GetCurrentProcess(), + GetCurrentProcess(), + GetCurrentProcess(), + &PostmasterHandle, + 0, + TRUE, + DUPLICATE_SAME_ACCESS) == 0) + ereport(FATAL, + (errmsg_internal("could not duplicate postmaster handle: error code %d", + (int) GetLastError()))); +#endif /* WIN32 */ +} |