top: avoid a potential SEGV during program termination

The backtrace shown in the bug report referenced below
illustrates a 'normal' program termination interrupted
with some signal, ultimately then causing a top crash.

So this commit just rearranges a little code such that
all signals will be blocked during that rather lengthy
end of program processing regardless of how initiated.

[ in that report, ignore the assertion regarding the ]
[ '-n' option. it obviously was not '1' since do_key ]
[ had been called, which otherwise wouldn't be true. ]

[ and when it is '1' the -d option would be ignored. ]

Reference(s):
https://bugzilla.redhat.com/show_bug.cgi?id=1737552

Signed-off-by: Jim Warner <james.warner@comcast.net>
This commit is contained in:
Jim Warner 2019-08-06 00:00:00 -05:00 committed by Craig Small
parent dd95e865de
commit d37f85c269

View File

@ -404,6 +404,11 @@ static void at_eoj (void) {
* The real program end */
static void bye_bye (const char *str) NORETURN;
static void bye_bye (const char *str) {
sigset_t ss;
// POSIX.1-2004 async-signal-safe: sigfillset, sigprocmask
sigfillset(&ss);
sigprocmask(SIG_BLOCK, &ss, NULL);
at_eoj(); // restore tty in preparation for exit
#ifdef ATEOJ_RPTSTD
{ proc_t *p;
@ -595,12 +600,6 @@ static void sig_abexit (int sig) {
* SIGUSR1 and SIGUSR2 */
static void sig_endpgm (int dont_care_sig) NORETURN;
static void sig_endpgm (int dont_care_sig) {
sigset_t ss;
// POSIX.1-2004 async-signal-safe: sigfillset, sigprocmask
sigfillset(&ss);
sigprocmask(SIG_BLOCK, &ss, NULL);
Frames_signal = BREAK_sig;
bye_bye(NULL);
(void)dont_care_sig;
} // end: sig_endpgm