Thread
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[PATCH v12a 2/4] Centralize resetting SIGCHLD handler
Heikki Linnakangas <heikki.linnakangas@iki.fi> — 2026-01-08T18:22:43Z
--- src/backend/postmaster/autovacuum.c | 2 -- src/backend/postmaster/bgworker.c | 1 - src/backend/postmaster/bgwriter.c | 5 ----- src/backend/postmaster/checkpointer.c | 5 ----- src/backend/postmaster/pgarch.c | 3 --- src/backend/postmaster/startup.c | 5 ----- src/backend/postmaster/syslogger.c | 5 ----- src/backend/postmaster/walsummarizer.c | 5 ----- src/backend/postmaster/walwriter.c | 5 ----- src/backend/replication/logical/slotsync.c | 1 - src/backend/replication/walreceiver.c | 3 --- src/backend/replication/walsender.c | 3 --- src/backend/tcop/postgres.c | 7 ------- src/backend/utils/init/miscinit.c | 14 ++++++++++++++ 14 files changed, 14 insertions(+), 50 deletions(-) diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c index 74574e1eaf9..e8180634db5 100644 --- a/src/backend/postmaster/autovacuum.c +++ b/src/backend/postmaster/autovacuum.c @@ -410,7 +410,6 @@ AutoVacLauncherMain(const void *startup_data, size_t startup_data_len) pqsignal(SIGUSR1, procsignal_sigusr1_handler); pqsignal(SIGUSR2, avl_sigusr2_handler); pqsignal(SIGFPE, FloatExceptionHandler); - pqsignal(SIGCHLD, SIG_DFL); /* * Create a per-backend PGPROC struct in shared memory. We must do this @@ -1417,7 +1416,6 @@ AutoVacWorkerMain(const void *startup_data, size_t startup_data_len) pqsignal(SIGUSR1, procsignal_sigusr1_handler); pqsignal(SIGUSR2, SIG_IGN); pqsignal(SIGFPE, FloatExceptionHandler); - pqsignal(SIGCHLD, SIG_DFL); /* * Create a per-backend PGPROC struct in shared memory. We must do this diff --git a/src/backend/postmaster/bgworker.c b/src/backend/postmaster/bgworker.c index 0104a86b9ec..8ff6a88a141 100644 --- a/src/backend/postmaster/bgworker.c +++ b/src/backend/postmaster/bgworker.c @@ -782,7 +782,6 @@ BackgroundWorkerMain(const void *startup_data, size_t startup_data_len) pqsignal(SIGPIPE, SIG_IGN); pqsignal(SIGUSR2, SIG_IGN); - pqsignal(SIGCHLD, SIG_DFL); /* * If an exception is encountered, processing resumes here. diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c index 1d8947774a9..efd041832a8 100644 --- a/src/backend/postmaster/bgwriter.c +++ b/src/backend/postmaster/bgwriter.c @@ -109,11 +109,6 @@ BackgroundWriterMain(const void *startup_data, size_t startup_data_len) pqsignal(SIGUSR1, procsignal_sigusr1_handler); pqsignal(SIGUSR2, SIG_IGN); - /* - * Reset some signals that are accepted by postmaster but not here - */ - pqsignal(SIGCHLD, SIG_DFL); - /* * We just started, assume there has been either a shutdown or * end-of-recovery snapshot. diff --git a/src/backend/postmaster/checkpointer.c b/src/backend/postmaster/checkpointer.c index e4075265495..98c2933a822 100644 --- a/src/backend/postmaster/checkpointer.c +++ b/src/backend/postmaster/checkpointer.c @@ -222,11 +222,6 @@ CheckpointerMain(const void *startup_data, size_t startup_data_len) pqsignal(SIGUSR1, procsignal_sigusr1_handler); pqsignal(SIGUSR2, SignalHandlerForShutdownRequest); - /* - * Reset some signals that are accepted by postmaster but not here - */ - pqsignal(SIGCHLD, SIG_DFL); - /* * Initialize so that first time-driven event happens at the correct time. */ diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c index fa4bdfe9ab9..36247c8a254 100644 --- a/src/backend/postmaster/pgarch.c +++ b/src/backend/postmaster/pgarch.c @@ -238,9 +238,6 @@ PgArchiverMain(const void *startup_data, size_t startup_data_len) pqsignal(SIGUSR1, procsignal_sigusr1_handler); pqsignal(SIGUSR2, pgarch_waken_stop); - /* Reset some signals that are accepted by postmaster but not here */ - pqsignal(SIGCHLD, SIG_DFL); - /* Unblock signals (they were blocked when the postmaster forked us) */ sigprocmask(SIG_SETMASK, &UnBlockSig, NULL); diff --git a/src/backend/postmaster/startup.c b/src/backend/postmaster/startup.c index cdbe53dd262..330c10ddb0b 100644 --- a/src/backend/postmaster/startup.c +++ b/src/backend/postmaster/startup.c @@ -234,11 +234,6 @@ StartupProcessMain(const void *startup_data, size_t startup_data_len) pqsignal(SIGUSR1, procsignal_sigusr1_handler); pqsignal(SIGUSR2, StartupProcTriggerHandler); - /* - * Reset some signals that are accepted by postmaster but not here - */ - pqsignal(SIGCHLD, SIG_DFL); - /* * Register timeouts needed for standby mode */ diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c index 9792f638718..74d082ea51c 100644 --- a/src/backend/postmaster/syslogger.c +++ b/src/backend/postmaster/syslogger.c @@ -284,11 +284,6 @@ SysLoggerMain(const void *startup_data, size_t startup_data_len) 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); - sigprocmask(SIG_SETMASK, &UnBlockSig, NULL); #ifdef WIN32 diff --git a/src/backend/postmaster/walsummarizer.c b/src/backend/postmaster/walsummarizer.c index e1aa102f41d..09a8301d669 100644 --- a/src/backend/postmaster/walsummarizer.c +++ b/src/backend/postmaster/walsummarizer.c @@ -264,11 +264,6 @@ WalSummarizerMain(const void *startup_data, size_t startup_data_len) ALLOCSET_DEFAULT_SIZES); MemoryContextSwitchTo(context); - /* - * Reset some signals that are accepted by postmaster but not here - */ - pqsignal(SIGCHLD, SIG_DFL); - /* * If an exception is encountered, processing resumes here. */ diff --git a/src/backend/postmaster/walwriter.c b/src/backend/postmaster/walwriter.c index 2c3b4f831aa..f2ba5720986 100644 --- a/src/backend/postmaster/walwriter.c +++ b/src/backend/postmaster/walwriter.c @@ -109,11 +109,6 @@ WalWriterMain(const void *startup_data, size_t startup_data_len) pqsignal(SIGUSR1, procsignal_sigusr1_handler); pqsignal(SIGUSR2, SIG_IGN); /* not used */ - /* - * Reset some signals that are accepted by postmaster but not here - */ - pqsignal(SIGCHLD, SIG_DFL); - /* * Create a memory context that we will do all our work in. We do this so * that we can reset the context during error recovery and thereby avoid diff --git a/src/backend/replication/logical/slotsync.c b/src/backend/replication/logical/slotsync.c index e75db69e3f6..91c17928e9c 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -1541,7 +1541,6 @@ ReplSlotSyncWorkerMain(const void *startup_data, size_t startup_data_len) pqsignal(SIGUSR1, procsignal_sigusr1_handler); pqsignal(SIGUSR2, SIG_IGN); pqsignal(SIGPIPE, SIG_IGN); - pqsignal(SIGCHLD, SIG_DFL); check_and_set_sync_info(MyProcPid); diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c index fabe3c73034..06d0fc1c23d 100644 --- a/src/backend/replication/walreceiver.c +++ b/src/backend/replication/walreceiver.c @@ -258,9 +258,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len) pqsignal(SIGUSR1, procsignal_sigusr1_handler); pqsignal(SIGUSR2, SIG_IGN); - /* Reset some signals that are accepted by postmaster but not here */ - pqsignal(SIGCHLD, SIG_DFL); - /* Load the libpq-specific functions */ load_file("libpqwalreceiver", false); if (WalReceiverFunctions == NULL) diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 79fc192b171..f0912f3f670 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -3744,9 +3744,6 @@ WalSndSignals(void) pqsignal(SIGUSR1, procsignal_sigusr1_handler); pqsignal(SIGUSR2, WalSndLastCycleHandler); /* request a last cycle and * shutdown */ - - /* Reset some signals that are accepted by postmaster but not here */ - pqsignal(SIGCHLD, SIG_DFL); } /* Report shared-memory space needed by WalSndShmemInit */ diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c index d01a09dd0c4..5d66c80567c 100644 --- a/src/backend/tcop/postgres.c +++ b/src/backend/tcop/postgres.c @@ -4285,13 +4285,6 @@ PostgresMain(const char *dbname, const char *username) pqsignal(SIGUSR1, procsignal_sigusr1_handler); pqsignal(SIGUSR2, SIG_IGN); pqsignal(SIGFPE, FloatExceptionHandler); - - /* - * Reset some signals that are accepted by postmaster but not by - * backend - */ - pqsignal(SIGCHLD, SIG_DFL); /* system() requires this on some - * platforms */ } /* Early initialization */ diff --git a/src/backend/utils/init/miscinit.c b/src/backend/utils/init/miscinit.c index ba191977697..8d898790c3e 100644 --- a/src/backend/utils/init/miscinit.c +++ b/src/backend/utils/init/miscinit.c @@ -143,6 +143,15 @@ InitPostmasterChild(void) elog(FATAL, "setsid() failed: %m"); #endif + /* + * Reset signals that are used by postmaster but not by child processes. + * + * Currently just SIGCHLD. The handlers for other signals are overridden + * later, depending on the child process type. + */ + pqsignal(SIGCHLD, SIG_DFL); /* system() requires this to be SIG_DFL rather + * than SIG_IGN on some platforms */ + /* * Every postmaster child process is expected to respond promptly to * SIGQUIT at all times. Therefore we centrally remove SIGQUIT from @@ -155,6 +164,11 @@ InitPostmasterChild(void) sigdelset(&BlockSig, SIGQUIT); sigprocmask(SIG_SETMASK, &BlockSig, NULL); + /* + * It is up to the *Main() function to set signal handlers appropriate for + * the child process and unblock the rest of the signals. + */ + /* Request a signal if the postmaster dies, if possible. */ PostmasterDeathSignalInit(); -- 2.53.0.1.gb2826b52eb --3rzmtywijtp4k7v2 Content-Type: text/x-diff; charset=us-ascii Content-Disposition: attachment; filename="v12a-0003-Replace-Latches-with-Interrupts.patch"