From 46eab4d838fabecfb7b6f42debdaaf5e53b8190f Mon Sep 17 00:00:00 2001
From: Colin Walters <walters@verbum.org>
Date: Tue, 21 May 2013 16:35:22 -0400
Subject: [PATCH] dbus-launch: Add an option --no-bus-fork

Previously, dbus-launch passed --fork to dbus-daemon, which (among
other things) causes it to open /dev/null for stdin/stdout/stderr.
Then, session components activated by dbus-daemon simply inherit these
defaults.

In a systemd environment, we really want the output of everything to
be hooked up to the journal by default.  At present, gdm launches
dbus-daemon for the user session, and I will be modifying it to pass
this flag by default.

This solves the "Where the $#%@ are my error messages?" issue I was
having while debugging something else...

https://bugs.freedesktop.org/show_bug.cgi?id=64843
---
 tools/dbus-launch.c |   65 +++++++++++++++++++++++++++++++-------------------
 1 files changed, 40 insertions(+), 25 deletions(-)

diff --git a/tools/dbus-launch.c b/tools/dbus-launch.c
index b2ffe41..3c0cd03 100644
--- a/tools/dbus-launch.c
+++ b/tools/dbus-launch.c
@@ -181,7 +181,7 @@ verbose (const char *format,
 static void
 usage (int ecode)
 {
-  fprintf (stderr, "dbus-launch [--version] [--help] [--sh-syntax] [--csh-syntax] [--auto-syntax] [--exit-with-session]\n");
+  fprintf (stderr, "dbus-launch [--version] [--help] [--sh-syntax] [--csh-syntax] [--auto-syntax] [--exit-with-session] [--no-bus-fork]\n");
   exit (ecode);
 }
 
@@ -596,6 +596,7 @@ kill_bus_when_session_ends (void)
 
 static void
 babysit (int   exit_with_session,
+         int   no_bus_fork,
          pid_t child_pid,
          int   read_bus_pid_fd)  /* read pid from here */
 {
@@ -659,11 +660,14 @@ babysit (int   exit_with_session,
 
       verbose ("=== Babysitter's intermediate parent continues again\n");
       
-      if (do_waitpid (child_pid) < 0)
+      if (!no_bus_fork)
         {
-          /* shouldn't happen */
-          fprintf (stderr, "Failed waitpid() waiting for bus daemon's parent\n");
-          exit (1);
+          if (do_waitpid (child_pid) < 0)
+            {
+              /* shouldn't happen */
+              fprintf (stderr, "Failed waitpid() waiting for bus daemon's parent\n");
+              exit (1);
+            }
         }
 
       verbose ("Babysitter's intermediate parent exiting\n");
@@ -674,25 +678,32 @@ babysit (int   exit_with_session,
   /* Child continues */
   verbose ("=== Babysitter process created\n");
 
-  verbose ("Reading PID from bus\n");
-      
-  switch (read_pid (read_bus_pid_fd, &bus_pid_to_kill))
+  if (no_bus_fork)
     {
-    case READ_STATUS_OK:
-      break;
-    case READ_STATUS_EOF:
-      fprintf (stderr, "EOF in dbus-launch reading PID from bus daemon\n");
-      exit (1);
-      break;
-    case READ_STATUS_ERROR:
-      fprintf (stderr, "Error in dbus-launch reading PID from bus daemon: %s\n",
-	       strerror (errno));
-      exit (1);
-      break;
+      bus_pid_to_kill = child_pid;
     }
+  else
+    {
+      verbose ("Reading PID from bus\n");
 
-  verbose ("Got PID %ld from daemon\n",
-           (long) bus_pid_to_kill);
+      switch (read_pid (read_bus_pid_fd, &bus_pid_to_kill))
+        {
+        case READ_STATUS_OK:
+          break;
+        case READ_STATUS_EOF:
+          fprintf (stderr, "EOF in dbus-launch reading PID from bus daemon\n");
+          exit (1);
+          break;
+        case READ_STATUS_ERROR:
+          fprintf (stderr, "Error in dbus-launch reading PID from bus daemon: %s\n",
+                   strerror (errno));
+          exit (1);
+          break;
+        }
+
+      verbose ("Got PID %ld from daemon\n",
+               (long) bus_pid_to_kill);
+    }
   
   if (exit_with_session)
     {
@@ -815,6 +826,7 @@ main (int argc, char **argv)
   int bourne_shell_syntax = FALSE;
   int auto_shell_syntax = FALSE;
   int autolaunch = FALSE;
+  int no_bus_fork = FALSE;
   int requires_arg = FALSE;
   int close_stderr = FALSE;
   int i;
@@ -853,6 +865,8 @@ main (int argc, char **argv)
         exit_with_session = TRUE;
       else if (strcmp (arg, "--close-stderr") == 0)
         close_stderr = TRUE;
+      else if (strcmp (arg, "--no-bus-fork") == 0)
+        no_bus_fork = TRUE;
       else if (strstr (arg, "--autolaunch=") == arg)
         {
           const char *s;
@@ -1038,6 +1052,7 @@ main (int argc, char **argv)
 
   if (ret == 0)
     {
+      const char *fork_option = no_bus_fork ? "--nofork" : "--fork";
       /* Child */
 #define MAX_FD_LEN 64
       char write_pid_fd_as_string[MAX_FD_LEN];
@@ -1077,7 +1092,7 @@ main (int argc, char **argv)
            * and will also reap the pre-forked bus
            * daemon
            */
-          babysit (exit_with_session, ret,
+          babysit (exit_with_session, no_bus_fork, ret,
                    bus_pid_to_babysitter_pipe[READ_END]);
           exit (0);
         }
@@ -1106,7 +1121,7 @@ main (int argc, char **argv)
         {
           execl (TEST_BUS_BINARY,
                  TEST_BUS_BINARY,
-                 "--fork",
+                 fork_option,
                  "--print-pid", write_pid_fd_as_string,
                  "--print-address", write_address_fd_as_string,
                  config_file ? "--config-file" : "--session",
@@ -1121,7 +1136,7 @@ main (int argc, char **argv)
 
       execl (DBUS_DAEMONDIR"/dbus-daemon",
              DBUS_DAEMONDIR"/dbus-daemon",
-             "--fork",
+             fork_option,
              "--print-pid", write_pid_fd_as_string,
              "--print-address", write_address_fd_as_string,
              config_file ? "--config-file" : "--session",
@@ -1140,7 +1155,7 @@ main (int argc, char **argv)
        */
       execlp ("dbus-daemon",
               "dbus-daemon",
-              "--fork",
+              fork_option,
               "--print-pid", write_pid_fd_as_string,
               "--print-address", write_address_fd_as_string,
               config_file ? "--config-file" : "--session",
-- 
1.7.1