daemon: if one of the standard fds is missing open it to /dev/null

Signed-off-by: Matthias Lederhofer <matled@gmx.net>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/daemon.c b/daemon.c
index a7636bc..01ccda3 100644 (file)
--- a/daemon.c
+++ b/daemon.c
@@ -662,6 +662,18 @@ static int service_loop(int socknum, int *socklist)
        }
 }
 
+/* if any standard file descriptor is missing open it to /dev/null */
+static void sanitize_stdfds(void)
+{
+       int fd = open("/dev/null", O_RDWR, 0);
+       while (fd != -1 && fd < 2)
+               fd = dup(fd);
+       if (fd == -1)
+               die("open /dev/null or dup failed: %s", strerror(errno));
+       if (fd > 2)
+               close(fd);
+}
+
 static int serve(int port)
 {
        int socknum, *socklist;
@@ -773,5 +785,7 @@ int main(int argc, char **argv)
                return execute(peer);
        }
 
+       sanitize_stdfds();
+
        return serve(port);
 }