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virsh-console: Avoid using signal() in multithreaded application

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Man page for signal states:

 "The effects of signal() in a multithreaded process are unspecified."

Switch signal() to sigaction in virsh console code.
This commit is contained in:
Peter Krempa 2013-08-29 18:30:06 +02:00
parent 02eaf1821c
commit 3e29c77a26
1 changed files with 27 additions and 25 deletions
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52
tools/virsh-console.c
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@ -312,32 +312,34 @@ vshRunConsole(vshControl *ctl,
const char *dev_name, const char *dev_name,
unsigned int flags) unsigned int flags)
{ {
int ret = -1;
void (*old_sigquit)(int);
void (*old_sigterm)(int);
void (*old_sigint)(int);
void (*old_sighup)(int);
void (*old_sigpipe)(int);
virConsolePtr con = NULL; virConsolePtr con = NULL;
int ret = -1;
/* Put STDIN into raw mode so that stuff typed struct sigaction old_sigquit;
does not echo to the screen (the TTY reads will struct sigaction old_sigterm;
result in it being echoed back already), and struct sigaction old_sigint;
also ensure Ctrl-C, etc is blocked, and misc struct sigaction old_sighup;
other bits */ struct sigaction old_sigpipe;
struct sigaction sighandler = {.sa_handler = virConsoleHandleSignal,
.sa_flags = SA_SIGINFO };
sigemptyset(&sighandler.sa_mask);
/* Put STDIN into raw mode so that stuff typed does not echo to the screen
* (the TTY reads will result in it being echoed back already), and also
* ensure Ctrl-C, etc is blocked, and misc other bits */
if (vshTTYMakeRaw(ctl, true) < 0) if (vshTTYMakeRaw(ctl, true) < 0)
goto resettty; goto resettty;
/* Trap all common signals so that we can safely restore /* Trap all common signals so that we can safely restore the original
the original terminal settings on STDIN before the * terminal settings on STDIN before the process exits - people don't like
process exits - people don't like being left with a * being left with a messed up terminal ! */
messed up terminal ! */
old_sigquit = signal(SIGQUIT, virConsoleHandleSignal);
old_sigterm = signal(SIGTERM, virConsoleHandleSignal);
old_sigint = signal(SIGINT, virConsoleHandleSignal);
old_sighup = signal(SIGHUP, virConsoleHandleSignal);
old_sigpipe = signal(SIGPIPE, virConsoleHandleSignal);
got_signal = 0; got_signal = 0;
sigaction(SIGQUIT, &sighandler, &old_sigquit);
sigaction(SIGTERM, &sighandler, &old_sigterm);
sigaction(SIGINT, &sighandler, &old_sigint);
sigaction(SIGHUP, &sighandler, &old_sighup);
sigaction(SIGPIPE, &sighandler, &old_sigpipe);
if (VIR_ALLOC(con) < 0) if (VIR_ALLOC(con) < 0)
goto cleanup; goto cleanup;
@ -384,11 +386,11 @@ cleanup:
virConsoleFree(con); virConsoleFree(con);
/* Restore original signal handlers */ /* Restore original signal handlers */
signal(SIGPIPE, old_sigpipe); sigaction(SIGQUIT, &old_sigquit, NULL);
signal(SIGHUP, old_sighup); sigaction(SIGTERM, &old_sigterm, NULL);
signal(SIGINT, old_sigint); sigaction(SIGINT, &old_sigint, NULL);
signal(SIGTERM, old_sigterm); sigaction(SIGHUP, &old_sighup, NULL);
signal(SIGQUIT, old_sigquit); sigaction(SIGPIPE, &old_sigpipe, NULL);
resettty: resettty:
/* Put STDIN back into the (sane?) state we found /* Put STDIN back into the (sane?) state we found