MINOR: don't close stdio anymore

Closing the standard IO FDs (0,1,2) can be troublesome, especially in
the case of the master-worker.

Instead of closing those FDs, they are now pointing to /dev/null which
prevents sending debugging messages to the wrong FDs.

This patch could be backported in 1.8.

diff --git a/src/haproxy.c b/src/haproxy.c
index 494ebed0169362b26d3d9347b981bbc438e958ae..e98420e229e21ae744d9fdb3aee3388756a50908 100644 (file)
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -889,6 +889,36 @@ static void dump(struct sig_handler *sh)
        pool_gc(NULL);
 }
 
+/*
+ *  This function dup2 the stdio FDs (0,1,2) with <fd>, then closes <fd>
+ *  If <fd> < 0, it opens /dev/null and use it to dup
+ *
+ *  In the case of chrooting, you have to open /dev/null before the chroot, and
+ *  pass the <fd> to this function
+ */
+static void stdio_quiet(int fd)
+{
+       if (fd < 0)
+               fd = open("/dev/null", O_RDWR, 0);
+
+       if (fd > -1) {
+               fclose(stdin);
+               fclose(stdout);
+               fclose(stderr);
+
+               dup2(fd, 0);
+               dup2(fd, 1);
+               dup2(fd, 2);
+               if (fd > 2)
+                       close(fd);
+               return;
+       }
+
+       ha_alert("Cannot open /dev/null\n");
+       exit(EXIT_FAILURE);
+}
+
+
 /* This function check if cfg_cfgfiles containes directories.
  * If it find one, it add all the files (and only files) it containes
  * in cfg_cfgfiles in place of the directory (and remove the directory).
@@ -2590,7 +2620,7 @@ int main(int argc, char **argv)
        } else {
                if ((global.mode & MODE_QUIET) && !(global.mode & MODE_VERBOSE)) {
                        /* detach from the tty */
-                       fclose(stdin); fclose(stdout); fclose(stderr);
+                       stdio_quiet(-1);
                }
        }
 
@@ -2683,6 +2713,7 @@ int main(int argc, char **argv)
                struct peers *curpeers;
                int ret = 0;
                int proc;
+               int devnullfd = -1;
 
                children = calloc(global.nbproc, sizeof(int));
                /*
@@ -2797,7 +2828,9 @@ int main(int argc, char **argv)
                                if ((!(global.mode & MODE_QUIET) || (global.mode & MODE_VERBOSE)) &&
                                        (global.mode & MODE_DAEMON)) {
                                        /* detach from the tty, this is required to properly daemonize. */
-                                       fclose(stdin); fclose(stdout); fclose(stderr);
+                                       if ((getenv("HAPROXY_MWORKER_REEXEC") == NULL))
+                                               stdio_quiet(-1);
+
                                        global.mode &= ~MODE_VERBOSE;
                                        global.mode |= MODE_QUIET; /* ensure that we won't say anything from now */
                                        setsid();
@@ -2816,6 +2849,14 @@ int main(int argc, char **argv)
                /* child must never use the atexit function */
                atexit_flag = 0;
 
+               if (!(global.mode & MODE_QUIET) || (global.mode & MODE_VERBOSE)) {
+                       devnullfd = open("/dev/null", O_RDWR, 0);
+                       if (devnullfd < 0) {
+                               ha_alert("Cannot open /dev/null\n");
+                               exit(EXIT_FAILURE);
+                       }
+               }
+
                /* Must chroot and setgid/setuid in the children */
                /* chroot if needed */
                if (global.chroot != NULL) {
@@ -2908,7 +2949,7 @@ int main(int argc, char **argv)
                 */
                if (!(global.mode & MODE_QUIET) || (global.mode & MODE_VERBOSE)) {
                        /* detach from the tty */
-                       fclose(stdin); fclose(stdout); fclose(stderr);
+                       stdio_quiet(devnullfd);
                        global.mode &= ~MODE_VERBOSE;
                        global.mode |= MODE_QUIET; /* ensure that we won't say anything from now */
                }