add inotify support (FDO Bz#13268)

2008-01-14  John (J5) Palmieri  <johnp@redhat.com>

	* patch by Frederic Crozat <fcrozat at mandriva dot com> (FDO Bz#
	13268)

	* add inotify support

	* bus/Makefile.am: add inotify module to the build

	* bus/dir-watch-inotify.c: inotify module based off the dnotify and
	kqueue modules

	* configure.in: add checks and switch for inotify
	also add a printout at the end of configure if inotify and kqueue
	support is being built in (dnotify already had this)

2 files changed, 160 insertions, 0 deletions

diff --git a/bus/Makefile.am b/bus/Makefile.am
index 4648a31d..3b4f69db 100644
--- a/bus/Makefile.am
+++ b/bus/Makefile.am
@@ -25,12 +25,16 @@ endif
 if DBUS_BUS_ENABLE_KQUEUE
 DIR_WATCH_SOURCE=dir-watch-kqueue.c
 else
+if DBUS_BUS_ENABLE_INOTIFY
+DIR_WATCH_SOURCE=dir-watch-inotify.c
+else
 if DBUS_BUS_ENABLE_DNOTIFY_ON_LINUX
 DIR_WATCH_SOURCE=dir-watch-dnotify.c
 else
 DIR_WATCH_SOURCE=dir-watch-default.c
 endif
 endif
+endif
 
 BUS_SOURCES=					\
 	activation.c				\
diff --git a/bus/dir-watch-inotify.c b/bus/dir-watch-inotify.c
new file mode 100644
index 00000000..0f3c155c
--- /dev/null
+++ b/bus/dir-watch-inotify.c
@@ -0,0 +1,156 @@
+/* -*- mode: C; c-file-style: "gnu" -*- */
+/* dir-watch-inotify.c  OS specific directory change notification for message bus
+ *
+ * Copyright (C) 2003 Red Hat, Inc.
+ *           (c) 2006 Mandriva
+ *
+ * Licensed under the Academic Free License version 2.1
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+#include <config.h>
+
+#define _GNU_SOURCE
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/inotify.h>
+#include <sys/types.h>
+#include <signal.h>
+#include <errno.h>
+
+#include <dbus/dbus-internals.h>
+#include <dbus/dbus-watch.h>
+#include "dir-watch.h"
+
+#define MAX_DIRS_TO_WATCH 128
+
+/* use a static array to avoid handling OOM */
+static int wds[MAX_DIRS_TO_WATCH];
+static int num_wds = 0;
+static int inotify_fd = -1;
+static DBusWatch *watch = NULL;
+static DBusLoop *loop = NULL;
+
+static dbus_bool_t
+_inotify_watch_callback (DBusWatch *watch, unsigned int condition, void *data)
+{
+  return dbus_watch_handle (watch, condition);
+}
+
+static dbus_bool_t
+_handle_inotify_watch (DBusWatch *watch, unsigned int flags, void *data)
+{
+  struct inotify_event ev;
+  size_t res;
+  pid_t pid;
+
+  res = read (inotify_fd, &ev, sizeof(ev));
+
+  if (res > 0)
+    {
+      pid = getpid ();
+      _dbus_verbose ("Sending SIGHUP signal on reception of a inotify event\n");
+      (void) kill (pid, SIGHUP);
+    }
+  else if (res < 0 && errno == EBADF)
+    {
+      if (watch != NULL)
+	{
+	  _dbus_loop_remove_watch (loop, watch, _inotify_watch_callback, NULL);
+          _dbus_watch_unref (watch);
+	  watch = NULL;
+	}
+      pid = getpid ();
+      _dbus_verbose ("Sending SIGHUP signal since inotify fd has been closed\n");
+      (void) kill (pid, SIGHUP);
+    }
+
+  return TRUE;
+}
+void
+bus_watch_directory (const char *dir, BusContext *context)
+{
+  int wd;
+
+  _dbus_assert (dir != NULL);
+
+  if (inotify_fd == -1) {
+     inotify_fd = inotify_init ();
+     if (inotify_fd <= 0) {
+      _dbus_warn ("Cannot initialize inotify\n");
+      goto out;
+     } 
+     loop = bus_context_get_loop (context);
+
+     watch = _dbus_watch_new (inotify_fd, DBUS_WATCH_READABLE, TRUE,
+                              _handle_inotify_watch, NULL, NULL);
+
+	if (watch == NULL)
+          {
+            _dbus_warn ("Unable to create inotify watch\n");
+	    goto out;
+	  }
+
+	if (!_dbus_loop_add_watch (loop, watch, _inotify_watch_callback,
+                                   NULL, NULL))
+          {
+            _dbus_warn ("Unable to add reload watch to main loop");
+	    _dbus_watch_unref (watch);
+	    watch = NULL;
+            goto out;
+	  }
+  }
+
+
+  if (num_wds >= MAX_DIRS_TO_WATCH )
+    {
+      _dbus_warn ("Cannot watch config directory '%s'. Already watching %d directories\n", dir, MAX_DIRS_TO_WATCH);
+      goto out;
+    }
+
+  wd = inotify_add_watch (inotify_fd, dir, IN_MODIFY);
+  if (wd < 0)
+    {
+      _dbus_warn ("Cannot setup inotify for '%s'; error '%s'\n", dir, _dbus_strerror (errno));
+      goto out;
+    }
+
+  wds[num_wds++] = wd;
+  _dbus_verbose ("Added watch on config directory '%s'\n", dir);
+
+ out:
+  ;
+}
+
+void 
+bus_drop_all_directory_watches (void)
+{
+  int i;
+ 
+  _dbus_verbose ("Dropping all watches on config directories\n");
+ 
+  for (i = 0; i < num_wds; i++)
+    {
+      if (inotify_rm_watch(inotify_fd, wds[i]) != 0)
+	{
+	  _dbus_verbose ("Error closing fd %d for config directory watch\n", wds[i]);
+	}
+    }
+  
+  num_wds = 0;
+}