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

[Jonathan Nieder <jrnieder@gmail.com>]

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

>> I think you could just replace your signal() calls with:
>> 
>>   sigchain_push(SIGINT, SIG_IGN);
>>   ...
>>   sigchain_pop(SIGINT);
>
> Which, FWIW, would look like this:

Something in this direction on top?

I think sigchain_push ought to accept a context object.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
diff --git a/run-command.c b/run-command.c
index 24e0f46..efdac84 100644
--- a/run-command.c
+++ b/run-command.c
@@ -103,6 +103,7 @@ 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 */
 
+	the_child = NULL;
 	sigchain_pop(SIGINT);
 	sigchain_pop(SIGQUIT);
 
@@ -139,6 +140,19 @@ static int wait_or_whine(pid_t pid, const char *argv0, int silent_exec_failure)
 	return code;
 }
 
+static struct child_process *the_child;
+
+static void interrupted_with_child(int sig)
+{
+	if (the_child && the_child->pid > 0) {
+		while ((waiting = waitpid(pid, NULL, 0)) < 0 && errno == EINTR)
+			;	/* nothing */
+		the_child = NULL;
+	}
+	sigchain_pop(sig);
+	raise(sig);
+}
+
 int start_command(struct child_process *cmd)
 {
 	int need_in, need_out, need_err;
@@ -206,8 +220,11 @@ fail_pipe:
 		notify_pipe[0] = notify_pipe[1] = -1;
 
 	fflush(NULL);
-	sigchain_push(SIGINT, SIG_IGN);
-	sigchain_push(SIGQUIT, SIG_IGN);
+	if (the_child)
+		die("What?  _Two_ children?");
+	the_child = cmd;
+	sigchain_push(SIGINT, interrupted_with_child);
+	sigchain_push(SIGQUIT, interrupted_with_child);
 	cmd->pid = fork();
 	if (!cmd->pid) {
 		sigchain_pop(SIGINT);