Re: RFC: [PATCH] ignore SIGINT&QUIT while waiting for external command

From

Jeff King <peff@peff.net>

Date

Oct 19, 2010, 13:40 UTC

Message-ID

<20101019134040.GA3956@sigill.intra.peff.net>

In-Reply-To

<20101019133236.GA804@sigill.intra.peff.net>

On Tue, Oct 19, 2010 at 09:32:36AM -0400, Jeff King wrote:

> How does this interact with the sigchain code? If I do:
> 
>   start_command(...);
>   sigchain_push(...);
>   finish_command(...);
> 
> we will overwrite the function pushed in the sigchain_push with a stale
> handler. I think you could just replace your signal() calls with:
> 
>   sigchain_push(SIGINT, SIG_IGN);
>   ...
>   sigchain_pop(SIGINT);

Which, FWIW, would look like this:

diff --git a/run-command.c b/run-command.c
index 2a1041e..24e0f46 100644
--- a/run-command.c
+++ b/run-command.c
@@ -1,6 +1,7 @@
 #include "cache.h"
 #include "run-command.h"
 #include "exec_cmd.h"
+#include "sigchain.h"
 
 static inline void close_pair(int fd[2])
 {
@@ -102,6 +103,9 @@ static int wait_or_whine(pid_t pid, const char *argv0, int silent_exec_failure)
 	while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
 		;	/* nothing */
 
+	sigchain_pop(SIGINT);
+	sigchain_pop(SIGQUIT);
+
 	if (waiting < 0) {
 		failed_errno = errno;
 		error("waitpid for %s failed: %s", argv0, strerror(errno));
@@ -202,8 +206,12 @@ fail_pipe:
 		notify_pipe[0] = notify_pipe[1] = -1;
 
 	fflush(NULL);
+	sigchain_push(SIGINT, SIG_IGN);
+	sigchain_push(SIGQUIT, SIG_IGN);
 	cmd->pid = fork();
 	if (!cmd->pid) {
+		sigchain_pop(SIGINT);
+		sigchain_pop(SIGQUIT);
 		/*
 		 * Redirect the channel to write syscall error messages to
 		 * before redirecting the process's stderr so that all die()