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ca3c5c6b52
Thanks-to: Lev Danilski <8o55kd+1v8xnjsby8b9k@pokemail.net> Closes: https://bugs.gentoo.org/631316 Package-Manager: Portage-2.3.64, Repoman-2.3.12 Signed-off-by: Lars Wendler <polynomial-c@gentoo.org>
66 lines
1.8 KiB
Diff
66 lines
1.8 KiB
Diff
# Rework SIGCHLD handler to anticipate multiple children dying while the
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# handler is being executed.
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#
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# Without the patch if multiple SIGCHLD signals are received while the signal
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# handler is being executed, the first will be left in pending state and the
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# extra discarded. Due to the children processing logic in netplugd, the ones
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# which were missed will never be waited, left as zombies.
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#
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# Implementation of the signal handler is following suggested handling in
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# https://www.gnu.org/software/libc/manual/html_node/Merged-Signals.html
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#
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# The patch strives to change only the children wait logic in the signal
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# handler, it doesn't try to enhance write call error handling or the unsafe
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# call to exit/do_log. Also the formatting is left as it was in the original
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# code.
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--- a/main.c
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+++ b/main.c
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@@ -153,17 +153,29 @@ static int child_handler_pipe[2];
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static void
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child_handler(int sig, siginfo_t *info, void *v)
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{
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- struct child_exit ce;
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- int ret;
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- ssize_t s = 0;
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+ int old_errno = errno;
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assert(sig == SIGCHLD);
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- ce.pid = info->si_pid;
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- ret = waitpid(info->si_pid, &ce.status, 0);
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- if (ret == info->si_pid)
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+ while (1)
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{
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- s = write(child_handler_pipe[1], &ce, sizeof(ce));
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+ pid_t pid;
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+ int status;
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+
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+ do
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+ {
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+ errno = 0;
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+ pid = waitpid(WAIT_ANY, &status, WNOHANG);
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+ } while (pid <= 0 && errno == EINTR);
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+
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+ if (pid <= 0)
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+ {
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+ break;
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+ }
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+
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+ struct child_exit ce = { .pid = pid, .status = status };
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+
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+ ssize_t s = write(child_handler_pipe[1], &ce, sizeof(ce));
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if (s == -1)
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{
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@@ -171,6 +183,9 @@ child_handler(int sig, siginfo_t *info, void *v)
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exit(1);
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}
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}
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+
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+ errno = old_errno;
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+ return;
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}
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/* Poll the existing interface state, so we can catch any state
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