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report that QEMU process was killed by a signal

PATCH Superseded Gleb Natapov 2 participants 3 messages Mar 14, 2011

v1 of 3 Superseded Latest is v3 →

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Gleb Natapov

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#0 lore raw

PATCH 1/1 report that QEMU process was killed by a signal

Currently when rogue script kills QEMU process (using TERM/INT/HUP signal) it looks indistinguishable from system shutdown. Lets report that QMEU was killed and leave some clues about the killed identity.

Signed-off-by Gleb Natapov <[email protected]>
os-posix.c +4 -2
index 38c29d1..7e175e8 100644
@@ -61,8 +61,9 @@ void os_setup_early_signal_handling(void)
     sigaction(SIGPIPE, &act, NULL);
 }
 
-static void termsig_handler(int signal)
+static void termsig_handler(int signal, siginfo_t *info, void *c)
 {
+    fprintf(stderr, "Got signal %d from pid %d\n", info->si_signo, info->si_pid);
     qemu_system_shutdown_request();
 }
 

@@ -76,7 +77,8 @@ void os_setup_signal_handling(void)
     struct sigaction act;
 
     memset(&act, 0, sizeof(act));
-    act.sa_handler = termsig_handler;
+    act.sa_sigaction = termsig_handler;
+    act.sa_flags = SA_SIGINFO;
     sigaction(SIGINT,  &act, NULL);
     sigaction(SIGHUP,  &act, NULL);
     sigaction(SIGTERM, &act, NULL);

--
Gleb.

#1 lore raw
Quoted 3 lines · Gleb Natapov

Currently when rogue script kills QEMU process (using TERM/INT/HUP signal) it looks indistinguishable from system shutdown. Lets report that QMEU was killed and leave some clues about the killed identity.

Good idea, but....

Quoted 7 lines
Signed-off-by Gleb Natapov <[email protected]>
os-posix.c +0 -0
index 38c29d1..7e175e8 100644

os-posix.c void os_setup_early_signal_handling(void) · line 67

Quoted 8 lines
os-posix.c +2 -1
@@ -61,8 +61,9 @@ void os_setup_early_signal_handling(void)
     sigaction(SIGPIPE, &act, NULL);
 }
 
-static void termsig_handler(int signal)
+static void termsig_handler(int signal, siginfo_t *info, void *c)
 {
+    fprintf(stderr, "Got signal %d from pid %d\n", info->si_signo, info->si_pid);
     qemu_system_shutdown_request();

...fprintf() isn't async signal safe. It could deadlock the process if it malloc()s while doing the arg formatting & the interrupted thread was already holding a malloc() lock, or indeed if the stdio impl itself has internal locks which are held. So this data needs to be manually output using just write()

Regards,
Daniel

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author
#2 lore raw
Quoted 17 lines · Daniel P. Berrange
Quoted 3 lines · Gleb Natapov

Currently when rogue script kills QEMU process (using TERM/INT/HUP signal) it looks indistinguishable from system shutdown. Lets report that QMEU was killed and leave some clues about the killed identity.

Good idea, but....

Quoted 10 lines
Signed-off-by Gleb Natapov <[email protected]>
os-posix.c +0 -0
index 38c29d1..7e175e8 100644
@@ -61,8 +61,9 @@ void os_setup_early_signal_handling(void)
     sigaction(SIGPIPE, &act, NULL);
 }
Quoted 12 lines

os-posix.c void os_setup_early_signal_handling(void) · line 67

Quoted 5 lines
os-posix.c +2 -1
-static void termsig_handler(int signal)
+static void termsig_handler(int signal, siginfo_t *info, void *c)
 {
+    fprintf(stderr, "Got signal %d from pid %d\n", info->si_signo, info->si_pid);
     qemu_system_shutdown_request();

...fprintf() isn't async signal safe. It could deadlock the process if it malloc()s while doing the arg formatting & the interrupted thread was already holding a malloc() lock, or indeed if the stdio impl itself has internal locks which are held. So this data needs to be manually output using just write()

Or we can save info->si_signo && info->si_pid in global variables and print this when shutdown is performed by main loop. Will send updated patch.

--
Gleb.