Fix elog(FATAL) before PostmasterMain() or just after fork().

nmisch · nmisch · commit 6151769f6ef5 · 2024-12-10T13:52:02.000-08:00
Since commit 97550c0, these failed with "PANIC: proc_exit() called in child process" due to uninitialized or stale MyProcPid. That was reachable if close() failed in ClosePostmasterPorts() or setlocale(category, "C") failed, both unlikely. Back-patch to v13 (all supported versions). Discussion: https://postgr.es/m/20241208034614.45.nmisch@google.com
diff --git a/src/backend/main/main.c b/src/backend/main/main.c
@@ -33,6 +33,7 @@
 
 #include "bootstrap/bootstrap.h"
 #include "common/username.h"
+#include "miscadmin.h"
 #include "port/atomics.h"
 #include "postmaster/postmaster.h"
 #include "storage/s_lock.h"
@@ -96,6 +97,7 @@ main(int argc, char *argv[])
 	 * localization of messages may not work right away, and messages won't go
 	 * anywhere but stderr until GUC settings get loaded.
 	 */
+	MyProcPid = getpid();
 	MemoryContextInit();
 
 	/*
diff --git a/src/backend/postmaster/fork_process.c b/src/backend/postmaster/fork_process.c
@@ -20,6 +20,7 @@
 #include <openssl/rand.h>
 #endif
 
+#include "miscadmin.h"
 #include "postmaster/fork_process.h"
 
 #ifndef WIN32
@@ -63,6 +64,7 @@ fork_process(void)
 	if (result == 0)
 	{
 		/* fork succeeded, in child */
+		MyProcPid = getpid();
 #ifdef LINUX_PROFILE
 		setitimer(ITIMER_PROF, &prof_itimer, NULL);
 #endif
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
@@ -2649,7 +2649,7 @@ ClosePostmasterPorts(bool am_syslogger)
 
 
 /*
- * InitProcessGlobals -- set MyProcPid, MyStartTime[stamp], random seeds
+ * InitProcessGlobals -- set MyStartTime[stamp], random seeds
  *
  * Called early in the postmaster and every backend.
  */
@@ -2658,7 +2658,6 @@ InitProcessGlobals(void)
 {
 	unsigned int rseed;
 
-	MyProcPid = getpid();
 	MyStartTimestamp = GetCurrentTimestamp();
 	MyStartTime = timestamptz_to_time_t(MyStartTimestamp);
 

Original file line number	Diff line number	Diff line change
`@@ -2649,7 +2649,7 @@ ClosePostmasterPorts(bool am_syslogger)`
`2649`	`2649`
`2650`	`2650`
`2651`	`2651`	`/*`
`2652`		`- * InitProcessGlobals -- set MyProcPid, MyStartTime[stamp], random seeds`
	`2652`	`+ * InitProcessGlobals -- set MyStartTime[stamp], random seeds`
`2653`	`2653`	`*`
`2654`	`2654`	`* Called early in the postmaster and every backend.`
`2655`	`2655`	`*/`
`@@ -2658,7 +2658,6 @@ InitProcessGlobals(void)`
`2658`	`2658`	`{`
`2659`	`2659`	`unsigned int rseed;`
`2660`	`2660`
`2661`		`- MyProcPid = getpid();`
`2662`	`2661`	`MyStartTimestamp = GetCurrentTimestamp();`
`2663`	`2662`	`MyStartTime = timestamptz_to_time_t(MyStartTimestamp);`
`2664`	`2663`