2003-04-06 Havoc Pennington <hp@pobox.com>

	* dbus/dbus-sysdeps.c (_dbus_become_daemon): write the pidfile
	here in the parent process, so we can return an error if it
	fails. Also, move some of the code into the child so the parent
	is less hosed if we fail midway through.

	* bus/bus.c (bus_context_new): move pidfile detection further up
	in the function, before we start overwriting sockets and such.

	* bus/messagebus.in: adjust this a bit, not sure if it will work.

	* configure.in: add --with-system-pid-file and --with-system-socket

2003-04-06  Colin Walters  <walters@verbum.org>

	* configure.in (DBUS_SYSTEM_PID_FILE): New variable.

	* bus/system.conf.in: Declare a pidfile.

	* bus/bus.c (bus_context_new): Test for an existing pid file, and
	create one (if appropriate).

	* bus/config-parser.c (enum ElementType) [ELEMENT_PIDFILE]: New.
	(struct BusConfigParser) [pidfile]: New.
	(element_type_to_name, merge_included, start_busconfig_child)
	(bus_config_parser_end_element, bus_config_parser_content): Handle it.
	(bus_config_parser_unref): Free it.
	(bus_config_parser_get_pidfile): New function.

	* bus/config-parser.h (_dbus_write_pid_file): Prototype.

	* dbus/dbus-errors.h (DBUS_ERROR_PIDFILE_EXISTS): New error.

	* dbus/dbus-sysdeps.c (_dbus_write_pid_file): New function.

	* dbus/dbus-sysdeps.h: Prototype it.

5 files changed, 105 insertions, 7 deletions

diff --git a/bus/bus.c b/bus/bus.c
index 880f35d1..09a0b5bb 100644
--- a/bus/bus.c
+++ b/bus/bus.c
@@ -306,7 +306,7 @@ bus_context_new (const DBusString *config_file,
   DBusList **addresses;
   BusConfigParser *parser;
   DBusString full_address;
-  const char *user;
+  const char *user, *pidfile;
   char **auth_mechanisms;
   DBusList **auth_mechanisms_list;
   int len;
@@ -333,6 +333,31 @@ bus_context_new (const DBusString *config_file,
   parser = bus_config_load (config_file, error);
   if (parser == NULL)
     goto failed;
+
+  /* Check for an existing pid file. Of course this is a race;
+   * we'd have to use fcntl() locks on the pid file to
+   * avoid that. But we want to check for the pid file
+   * before overwriting any existing sockets, etc.
+   */
+  pidfile = bus_config_parser_get_pidfile (parser);
+  if (pidfile != NULL)
+    {
+      DBusString u;
+      DBusStat stbuf;
+      DBusError tmp_error;
+      
+      dbus_error_init (&tmp_error);
+      _dbus_string_init_const (&u, pidfile);
+      
+      if (_dbus_stat (&u, &stbuf, &tmp_error))
+	{
+	  dbus_set_error (error, DBUS_ERROR_FAILED,
+			  "The pid file \"%s\" exists, if the message bus is not running, remove this file",
+			  pidfile);
+	  dbus_error_free (&tmp_error);
+	  goto failed;
+	}
+    }
   
   context = dbus_new0 (BusContext, 1);
   if (context == NULL)
@@ -587,9 +612,27 @@ bus_context_new (const DBusString *config_file,
   /* Now become a daemon if appropriate */
   if (bus_config_parser_get_fork (parser))
     {
-      if (!_dbus_become_daemon (error))
+      DBusString u;
+
+      if (pidfile)
+        _dbus_string_init_const (&u, pidfile);
+      
+      if (!_dbus_become_daemon (pidfile ? &u : NULL, error))
         goto failed;
     }
+  else
+    {
+      /* Need to write PID file for ourselves, not for the child process */
+      if (pidfile != NULL)
+        {
+          DBusString u;
+
+          _dbus_string_init_const (&u, pidfile);
+          
+          if (!_dbus_write_pid_file (&u, _dbus_getpid (), error))
+            goto failed;
+        }
+    }
   
   bus_config_parser_unref (parser);
   _dbus_string_free (&full_address);
diff --git a/bus/config-parser.c b/bus/config-parser.c
index f9473ff9..1052dc2d 100644
--- a/bus/config-parser.c
+++ b/bus/config-parser.c
@@ -40,6 +40,7 @@ typedef enum
   ELEMENT_ALLOW,
   ELEMENT_DENY,
   ELEMENT_FORK,
+  ELEMENT_PIDFILE,
   ELEMENT_SERVICEDIR,
   ELEMENT_INCLUDEDIR,
   ELEMENT_TYPE
@@ -94,6 +95,8 @@ struct BusConfigParser
   DBusList *service_dirs; /**< Directories to look for services in */
   
   unsigned int fork : 1; /**< TRUE to fork into daemon mode */
+
+  char *pidfile;
 };
 
 static const char*
@@ -123,6 +126,8 @@ element_type_to_name (ElementType type)
       return "deny";
     case ELEMENT_FORK:
       return "fork";
+    case ELEMENT_PIDFILE:
+      return "pidfile";
     case ELEMENT_SERVICEDIR:
       return "servicedir";
     case ELEMENT_INCLUDEDIR:
@@ -222,6 +227,13 @@ merge_included (BusConfigParser *parser,
   
   if (included->fork)
     parser->fork = TRUE;
+
+  if (included->pidfile != NULL)
+    {
+      dbus_free (parser->pidfile);
+      parser->pidfile = included->pidfile;
+      included->pidfile = NULL;
+    }
   
   while ((link = _dbus_list_pop_first_link (&included->listen_on)))
     _dbus_list_append_link (&parser->listen_on, link);
@@ -284,6 +296,7 @@ bus_config_parser_unref (BusConfigParser *parser)
 
       dbus_free (parser->user);
       dbus_free (parser->bus_type);
+      dbus_free (parser->pidfile);
       
       _dbus_list_foreach (&parser->listen_on,
                           (DBusForeachFunction) dbus_free,
@@ -499,6 +512,19 @@ start_busconfig_child (BusConfigParser   *parser,
       
       return TRUE;
     }
+  else if (strcmp (element_name, "pidfile") == 0)
+    {
+      if (!check_no_attributes (parser, "pidfile", attribute_names, attribute_values, error))
+        return FALSE;
+
+      if (push_element (parser, ELEMENT_PIDFILE) == NULL)
+        {
+          BUS_SET_OOM (error);
+          return FALSE;
+        }
+
+      return TRUE;
+    }
   else if (strcmp (element_name, "listen") == 0)
     {
       if (!check_no_attributes (parser, "listen", attribute_names, attribute_values, error))
@@ -770,6 +796,7 @@ bus_config_parser_end_element (BusConfigParser   *parser,
     case ELEMENT_USER:
     case ELEMENT_TYPE:
     case ELEMENT_LISTEN:
+    case ELEMENT_PIDFILE:
     case ELEMENT_AUTH:
     case ELEMENT_SERVICEDIR:
     case ELEMENT_INCLUDEDIR:
@@ -1004,6 +1031,20 @@ bus_config_parser_content (BusConfigParser   *parser,
           return FALSE;
         }
 
+    case ELEMENT_PIDFILE:
+      {
+        char *s;
+
+        e->had_content = TRUE;
+        
+        if (!_dbus_string_copy_data (content, &s))
+          goto nomem;
+          
+        dbus_free (parser->pidfile);
+        parser->pidfile = s;
+      }
+      break;
+
     case ELEMENT_INCLUDE:
       {
         DBusString full_path;
@@ -1222,6 +1263,12 @@ bus_config_parser_get_fork (BusConfigParser   *parser)
   return parser->fork;
 }
 
+const char *
+bus_config_parser_get_pidfile (BusConfigParser   *parser)
+{
+  return parser->pidfile;
+}
+
 #ifdef DBUS_BUILD_TESTS
 #include <stdio.h>
 
diff --git a/bus/config-parser.h b/bus/config-parser.h
index af5c8260..93d41003 100644
--- a/bus/config-parser.h
+++ b/bus/config-parser.h
@@ -60,6 +60,7 @@ const char* bus_config_parser_get_type         (BusConfigParser *parser);
 DBusList**  bus_config_parser_get_addresses    (BusConfigParser *parser);
 DBusList**  bus_config_parser_get_mechanisms   (BusConfigParser *parser);
 dbus_bool_t bus_config_parser_get_fork         (BusConfigParser *parser);
+const char* bus_config_parser_get_pidfile      (BusConfigParser *parser);
 DBusList**  bus_config_parser_get_service_dirs (BusConfigParser *parser);
 
 /* Loader functions (backended off one of the XML parsers).  Returns a
diff --git a/bus/messagebus.in b/bus/messagebus.in
index 60c70777..45388a5e 100755
--- a/bus/messagebus.in
+++ b/bus/messagebus.in
@@ -7,7 +7,7 @@
 #               and other messages. See http://www.freedesktop.org/software/dbus/
 #
 # processname: dbus-daemon-1
-# pidfile: @EXPANDED_LOCALSTATEDIR@/messagebus.pid
+# pidfile: @DBUS_SYSTEM_PID_FILE@
 #
 
 # Sanity checks.
@@ -20,7 +20,7 @@ RETVAL=0
 
 start() {
     echo -n $"Starting system message bus: "
-    daemon dbus-daemon-1 --system
+    daemon --check messagebus dbus-daemon-1 --system
     RETVAL=$?
     echo
     [ $RETVAL -eq 0 ] && touch @EXPANDED_LOCALSTATEDIR@/lock/subsys/messagebus
@@ -28,7 +28,11 @@ start() {
 
 stop() {
     echo -n $"Stopping system message bus: "
-    killproc messagebus
+
+    ## we don't want to kill all the per-user dbus-daemon-1, we want
+    ## to use the pid file *only*; because we use the fake nonexistent 
+    ## program name "messagebus" that should be safe-ish
+    killproc messagebus -TERM
     RETVAL=$?
     echo
     if [ $RETVAL -eq 0 ]; then
@@ -59,7 +63,7 @@ case "$1" in
         fi
         ;;
     reload)
-        killproc messagebus -HUP
+        echo "Message bus can't reload its configuration, you have to restart it"
         RETVAL=$?
         ;;
     *)
diff --git a/bus/system.conf.in b/bus/system.conf.in
index 15a4972e..0e570575 100644
--- a/bus/system.conf.in
+++ b/bus/system.conf.in
@@ -20,11 +20,14 @@
   <!-- Fork into daemon mode -->
   <fork/>
 
+  <!-- Write a pid file -->
+  <pidfile>@DBUS_SYSTEM_PID_FILE@</pidfile>
+
   <!-- Only allow socket-credentials-based authentication -->
   <auth>EXTERNAL</auth>
 
   <!-- Only listen on a local socket -->
-  <listen>unix:path=@EXPANDED_LOCALSTATEDIR@/@DBUS_SYSTEM_SOCKET@</listen>
+  <listen>unix:path=@DBUS_SYSTEM_SOCKET@</listen>
 
   <policy context="default">
     <!-- Deny everything then punch holes -->