daemon/shell: refactor redirection of 0/1/2 from /dev/null

Both daemon.c and shell.c contain logic to open FDs 0/1/2 from
/dev/null if they are not already open.  Move the function in daemon.c
to setup.c and use it in shell.c, too.

While there, remove a 'not' that inverted the meaning of the comment.
The point is indeed to *avoid* messing up.

Signed-off-by: Thomas Rast <trast@inf.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 3 insertions, 9 deletions

diff --git a/shell.c b/shell.c
index 84b237fef3..d6fb9f0504 100644
--- a/shell.c
+++ b/shell.c
@@ -134,7 +134,6 @@ int main(int argc, char **argv)
 	char *prog;
 	const char **user_argv;
 	struct commands *cmd;
-	int devnull_fd;
 	int count;
 
 	git_setup_gettext();
@@ -143,15 +142,10 @@ int main(int argc, char **argv)
 
 	/*
 	 * Always open file descriptors 0/1/2 to avoid clobbering files
-	 * in die().  It also avoids not messing up when the pipes are
-	 * dup'ed onto stdin/stdout/stderr in the child processes we spawn.
+	 * in die().  It also avoids messing up when the pipes are dup'ed
+	 * onto stdin/stdout/stderr in the child processes we spawn.
 	 */
-	devnull_fd = open("/dev/null", O_RDWR);
-	while (devnull_fd >= 0 && devnull_fd <= 2)
-		devnull_fd = dup(devnull_fd);
-	if (devnull_fd == -1)
-		die_errno("opening /dev/null failed");
-	close (devnull_fd);
+	sanitize_stdfds();
 
 	/*
 	 * Special hack to pretend to be a CVS server