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Merge pull request #423 from lrh2000/su-fix-sigkill

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su: Fix never alarmed SIGKILL when session terminates
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Serge Hallyn 2021-10-31 12:36:03 -05:00 committed by GitHub
commit 387da46d73
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1 changed files with 17 additions and 11 deletions
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28
src/su.c
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@ -397,22 +397,28 @@ static void prepare_pam_close_session (void)
snprintf (kill_msg, sizeof kill_msg, _(" ...killed.\n"));
snprintf (wait_msg, sizeof wait_msg, _(" ...waiting for child to terminate.\n"));
/* Any signals other than SIGCHLD and SIGALRM will no longer have any effect,
* so it's time to block all of them. */
sigfillset (&ourset);
if (sigprocmask (SIG_BLOCK, &ourset, NULL) != 0) {
fprintf (stderr, _("%s: signal masking malfunction\n"), Prog);
kill_child (0);
/* Never reach (_exit called). */
}
/* Send SIGKILL to the child if it doesn't
* exit within 2 seconds (after SIGTERM) */
(void) signal (SIGALRM, kill_child);
(void) signal (SIGCHLD, catch_signals);
(void) alarm (2);
sigemptyset (&ourset);
if ((sigaddset (&ourset, SIGALRM) != 0)
|| (sigprocmask (SIG_BLOCK, &ourset, NULL) != 0)) {
fprintf (stderr, _("%s: signal masking malfunction\n"), Prog);
kill_child (0);
} else {
while (0 == waitpid (pid_child, &status, WNOHANG)) {
sigsuspend (&ourset);
}
pid_child = 0;
(void) sigprocmask (SIG_UNBLOCK, &ourset, NULL);
(void) sigdelset (&ourset, SIGALRM);
(void) sigdelset (&ourset, SIGCHLD);
while (0 == waitpid (pid_child, &status, WNOHANG)) {
sigsuspend (&ourset);
}
pid_child = 0;
(void) fputs (_(" ...terminated.\n"), stderr);
}