From 3cabe90143342408a964b7a05e3c212051a71e20 Mon Sep 17 00:00:00 2001 From: Heikki Linnakangas Date: Thu, 8 Jan 2026 20:22:43 +0200 Subject: [PATCH 2/5] Centralize resetting SIGCHLD handler --- 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 6fde740465f..89c2b4f9500 100644 --- a/src/backend/postmaster/autovacuum.c +++ b/src/backend/postmaster/autovacuum.c @@ -411,7 +411,6 @@ 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 @@ -1422,7 +1421,6 @@ 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 261ccd3f59c..d4031ac3787 100644 --- a/src/backend/postmaster/bgworker.c +++ b/src/backend/postmaster/bgworker.c @@ -795,7 +795,6 @@ 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 0956bd39a85..dbd670c16cc 100644 --- a/src/backend/postmaster/bgwriter.c +++ b/src/backend/postmaster/bgwriter.c @@ -108,11 +108,6 @@ 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 e03c19123bc..03aefa5b670 100644 --- a/src/backend/postmaster/checkpointer.c +++ b/src/backend/postmaster/checkpointer.c @@ -220,11 +220,6 @@ 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 82731e452fc..10a5ef9e15c 100644 --- a/src/backend/postmaster/pgarch.c +++ b/src/backend/postmaster/pgarch.c @@ -237,9 +237,6 @@ 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 86c5e376b40..8515bfb9653 100644 --- a/src/backend/postmaster/syslogger.c +++ b/src/backend/postmaster/syslogger.c @@ -283,11 +283,6 @@ 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 742137edad6..4e4eed4d076 100644 --- a/src/backend/postmaster/walsummarizer.c +++ b/src/backend/postmaster/walsummarizer.c @@ -263,11 +263,6 @@ 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 7c0e2809c17..8ca7b07e947 100644 --- a/src/backend/postmaster/walwriter.c +++ b/src/backend/postmaster/walwriter.c @@ -108,11 +108,6 @@ 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 062a08ccb88..5e1ee7e4728 100644 --- a/src/backend/replication/logical/slotsync.c +++ b/src/backend/replication/logical/slotsync.c @@ -1536,7 +1536,6 @@ 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 10e64a7d1f4..352a3f31e95 100644 --- a/src/backend/replication/walreceiver.c +++ b/src/backend/replication/walreceiver.c @@ -257,9 +257,6 @@ 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 2cde8ebc729..5acc8ee3ac8 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -3743,9 +3743,6 @@ 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 21de158adbb..b88ce440b1d 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 03f6c8479f2..fadf856d9bc 100644 --- a/src/backend/utils/init/miscinit.c +++ b/src/backend/utils/init/miscinit.c @@ -142,6 +142,15 @@ 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 @@ -154,6 +163,11 @@ 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(); -- 2.47.3