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.

10 files changed, 294 insertions, 52 deletions

diff --git a/ChangeLog b/ChangeLog
index ede733b3..75eed1b4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,43 @@
 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.
+
+2003-04-06  Havoc Pennington  <hp@pobox.com>
+
 	* bus/bus.c (bus_context_new): print the address in here, rather
 	than in main(), because we need to do it before forking the daemon
 
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 -->
diff --git a/configure.in b/configure.in
index d37a7c4b..e908d3ee 100644
--- a/configure.in
+++ b/configure.in
@@ -35,6 +35,8 @@ AC_ARG_WITH(xml,                [  --with-xml=[libxml/expat] XML library to use]
 AC_ARG_WITH(init-scripts,       [  --with-init-scripts=[redhat] Style of init scripts to install])
 AC_ARG_WITH(session-socket-dir, [  --with-session-socket-dir=[dirname] Where to put sockets for the per-login-session message bus])
 AC_ARG_WITH(test-socket-dir,    [  --with-test-socket-dir=[dirname] Where to put sockets for make check])
+AC_ARG_WITH(system-pid-file,    [  --with-system-pid-file=[pidfile] PID file for systemwide daemon])
+AC_ARG_WITH(system-socket,      [  --with-system-socket=[filename] UNIX domain socket for systemwide daemon])
 
 dnl DBUS_BUILD_TESTS controls unit tests built in to .c files 
 dnl and also some stuff in the test/ subdir
@@ -385,12 +387,9 @@ dnl Qt flags
 AC_SUBST(DBUS_QT_CXXFLAGS)
 AC_SUBST(DBUS_QT_LIBS)
 
-##### Set up location for system bus socket
-## name of socket relative to localstatedir
-DBUS_SYSTEM_SOCKET=run/dbus/system_bus_socket
-AC_SUBST(DBUS_SYSTEM_SOCKET)
-
 #### find the actual value for $prefix that we'll end up with
+##   (I know this is broken and should be done in the Makefile, but
+##    that's a major pain and almost nobody actually seems to care)
 REAL_PREFIX=
 if test "x$prefix" = "xNONE"; then
   REAL_PREFIX=$ac_default_prefix
@@ -421,18 +420,45 @@ EXPANDED_BINDIR=`eval echo $BINDIR_TMP`
 prefix=$old_prefix
 AC_SUBST(EXPANDED_BINDIR)
 
+#### Check our operating system
+operating_system=unknown
+if test -f /etc/redhat-release || test -f $EXPANDED_SYSCONFDIR/redhat-release ; then
+   operating_system=redhat
+fi
+
 #### Sort out init scripts
 
 if test x$with_init_scripts = x; then
-        if test -f /etc/redhat-release || test -f $EXPANDED_SYSCONFDIR/redhat-release ; then
-                with_init_scripts=redhat
-        else
-                with_init_scripts=none
-        fi
+    if test xredhat = x$operating_system ; then
+        with_init_scripts=redhat
+    else
+        with_init_scripts=none
+    fi
 fi
 
 AM_CONDITIONAL(DBUS_INIT_SCRIPTS_RED_HAT, test x$with_init_scripts = xredhat)
 
+
+##### Set up location for system bus socket
+if ! test -z "$with_system_socket"; then
+   DBUS_SYSTEM_SOCKET=$with_system_socket
+else
+   DBUS_SYSTEM_SOCKET=${EXPANDED_LOCALSTATEDIR}/run/dbus/system_bus_socket
+fi
+
+AC_SUBST(DBUS_SYSTEM_SOCKET)
+
+#### Set up the pid file
+if ! test -z "$with_system_pid_file"; then
+   DBUS_SYSTEM_PID_FILE=$with_system_pid_file
+elif test x$operating_system = xredhat ; then
+   DBUS_SYSTEM_PID_FILE=${EXPANDED_LOCALSTATEDIR}/run/messagebus.pid
+else
+   DBUS_SYSTEM_PID_FILE=${EXPANDED_LOCALSTATEDIR}/run/dbus/pid
+fi
+
+AC_SUBST(DBUS_SYSTEM_PID_FILE)
+
 #### Tell tests where to find certain stuff in builddir
 ABSOLUTE_TOP_BUILDDIR=`cd ${ac_top_builddir}. && pwd`
 
@@ -512,7 +538,8 @@ echo "
         Building GLib bindings:   ${have_glib}
         Using XML parser:         ${with_xml}
         Init scripts style:       ${with_init_scripts}
-        System bus socket:        ${EXPANDED_LOCALSTATEDIR}/${DBUS_SYSTEM_SOCKET}
+        System bus socket:        ${DBUS_SYSTEM_SOCKET}
+        System bus PID file:      ${DBUS_SYSTEM_PID_FILE}
         Session bus socket dir:   ${DBUS_SESSION_SOCKET_DIR}
         'make check' socket dir:  ${TEST_SOCKET_DIR}
 "
diff --git a/dbus/Makefile.am b/dbus/Makefile.am
index 2065e75e..7d5ed501 100644
--- a/dbus/Makefile.am
+++ b/dbus/Makefile.am
@@ -1,6 +1,6 @@
 
 INCLUDES=-I$(top_srcdir) $(DBUS_CLIENT_CFLAGS) -DDBUS_COMPILATION		\
-	-DDBUS_SYSTEM_BUS_PATH=\""@EXPANDED_LOCALSTATEDIR@/@DBUS_SYSTEM_SOCKET@"\"
+	-DDBUS_SYSTEM_BUS_PATH=\""@DBUS_SYSTEM_SOCKET@"\"
 
 dbusincludedir=$(includedir)/dbus-1.0/dbus
 
diff --git a/dbus/dbus-sysdeps.c b/dbus/dbus-sysdeps.c
index 7a389956..df921b17 100644
--- a/dbus/dbus-sysdeps.c
+++ b/dbus/dbus-sysdeps.c
@@ -1700,6 +1700,15 @@ _dbus_string_append_our_uid (DBusString *str)
   return _dbus_string_append_int (str, getuid ());
 }
 
+/**
+ * Gets our process ID
+ * @returns process ID
+ */
+unsigned long
+_dbus_getpid (void)
+{
+  return getpid ();
+}
 
 _DBUS_DEFINE_GLOBAL_LOCK (atomic);
 
@@ -2930,17 +2939,17 @@ _dbus_print_backtrace (void)
 /**
  * Does the chdir, fork, setsid, etc. to become a daemon process.
  *
+ * @param pidfile #NULL, or pidfile to create
  * @param error return location for errors
  * @returns #FALSE on failure
  */
 dbus_bool_t
-_dbus_become_daemon (DBusError *error)
+_dbus_become_daemon (const DBusString *pidfile,
+                     DBusError        *error)
 {
   const char *s;
+  pid_t child_pid;
 
-  /* This is so we don't prevent unmounting of devices. We divert
-   * all messages to syslog
-   */
   if (chdir ("/") < 0)
     {
       dbus_set_error (error, DBUS_ERROR_FAILED,
@@ -2948,29 +2957,7 @@ _dbus_become_daemon (DBusError *error)
       return FALSE;
     }
 
-  s = _dbus_getenv ("DBUS_DEBUG_OUTPUT");
-  if (s == NULL || *s == '\0')
-    {
-      int dev_null_fd;
-
-      /* silently ignore failures here, if someone
-       * doesn't have /dev/null we may as well try
-       * to continue anyhow
-       */
-
-      dev_null_fd = open ("/dev/null", O_RDWR);
-      if (dev_null_fd >= 0)
-        {
-         dup2 (dev_null_fd, 0);
-         dup2 (dev_null_fd, 1);
-         dup2 (dev_null_fd, 2);
-       }
-    }
-
-  /* Get a predictable umask */
-  umask (022);
-
-  switch (fork ())
+  switch ((child_pid = fork ()))
     {
     case -1:
       dbus_set_error (error, _dbus_error_from_errno (errno),
@@ -2978,10 +2965,41 @@ _dbus_become_daemon (DBusError *error)
       return FALSE;
       break;
 
-    case 0:      
+    case 0:
+      s = _dbus_getenv ("DBUS_DEBUG_OUTPUT");
+      if (s == NULL || *s == '\0')
+        {
+          int dev_null_fd;
+
+          /* silently ignore failures here, if someone
+           * doesn't have /dev/null we may as well try
+           * to continue anyhow
+           */
+
+          dev_null_fd = open ("/dev/null", O_RDWR);
+          if (dev_null_fd >= 0)
+            {
+              dup2 (dev_null_fd, 0);
+              dup2 (dev_null_fd, 1);
+              dup2 (dev_null_fd, 2);
+            }
+        }
+
+      /* Get a predictable umask */
+      umask (022);
       break;
 
     default:
+      if (pidfile)
+        {
+          if (!_dbus_write_pid_file (pidfile,
+                                     child_pid,
+                                     error))
+            {
+              kill (child_pid, SIGTERM);
+              return FALSE;
+            }
+        }
       _exit (0);
       break;
     }
@@ -2993,6 +3011,62 @@ _dbus_become_daemon (DBusError *error)
 }
 
 /**
+ * Creates a file containing the process ID.
+ *
+ * @param filename the filename to write to
+ * @param pid our process ID
+ * @param error return location for errors
+ * @returns #FALSE on failure
+ */
+dbus_bool_t
+_dbus_write_pid_file (const DBusString *filename,
+                      unsigned long     pid,
+		      DBusError        *error)
+{
+  const char *cfilename;
+  int fd;
+  FILE *f;
+
+  cfilename = _dbus_string_get_const_data (filename);
+  
+  fd = open (cfilename, O_WRONLY|O_CREAT|O_EXCL|O_BINARY, 0644);
+  
+  if (fd < 0)
+    {
+      dbus_set_error (error, _dbus_error_from_errno (errno),
+                      "Failed to open \"%s\": %s", cfilename,
+                      _dbus_strerror (errno));
+      return FALSE;
+    }
+
+  if ((f = fdopen (fd, "w")) == NULL)
+    {
+      dbus_set_error (error, _dbus_error_from_errno (errno),
+                      "Failed to fdopen fd %d: %s", fd, _dbus_strerror (errno));
+      close (fd);
+      return FALSE;
+    }
+  
+  if (fprintf (f, "%lu\n", pid) < 0)
+    {
+      dbus_set_error (error, _dbus_error_from_errno (errno),
+                      "Failed to write to \"%s\": %s", cfilename,
+                      _dbus_strerror (errno));
+      return FALSE;
+    }
+
+  if (fclose (f) == EOF)
+    {
+      dbus_set_error (error, _dbus_error_from_errno (errno),
+                      "Failed to close \"%s\": %s", cfilename,
+                      _dbus_strerror (errno));
+      return FALSE;
+    }
+  
+  return TRUE;
+}
+
+/**
  * Changes the user and group the bus is running as.
  *
  * @param uid the new user ID
diff --git a/dbus/dbus-sysdeps.h b/dbus/dbus-sysdeps.h
index 933e2775..0a4a34dd 100644
--- a/dbus/dbus-sysdeps.h
+++ b/dbus/dbus-sysdeps.h
@@ -119,6 +119,8 @@ dbus_bool_t _dbus_get_groups   (unsigned long      uid,
                                 unsigned long    **group_ids,
                                 int               *n_group_ids);
 
+unsigned long _dbus_getpid (void);
+
 typedef int dbus_atomic_t;
 
 dbus_atomic_t _dbus_atomic_inc (dbus_atomic_t *atomic);
@@ -216,11 +218,14 @@ dbus_bool_t _dbus_close            (int               fd,
 
 void        _dbus_print_backtrace  (void);
 
-dbus_bool_t _dbus_become_daemon    (DBusError *error);
-
-dbus_bool_t _dbus_change_identity  (unsigned long  uid,
-                                    unsigned long  gid,
-                                    DBusError     *error);
+dbus_bool_t _dbus_become_daemon   (const DBusString *pidfile,
+                                   DBusError        *error);
+dbus_bool_t _dbus_write_pid_file  (const DBusString *filename,
+                                   unsigned long     pid,
+                                   DBusError        *error);
+dbus_bool_t _dbus_change_identity (unsigned long     uid,
+                                   unsigned long     gid,
+                                   DBusError        *error);
 
 typedef void (* DBusSignalHandler) (int sig);