From 9225e01a984f730e6b2755a37e83c7ca4ee601cb Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Tue, 10 Jul 2007 22:41:39 +0000
Subject: [PATCH] Add FreeBSD kqueue support for watching for configuration
 file changes, much the same way we currently have for Linux with inotify.
 (Patch supplied by marcus, but autoconf check reversed, re #149)

git-svn-id: file:///home/lennart/svn/public/avahi/trunk@1495 941a03a8-eaeb-0310-b9a0-b1bbd8fe43fe
---
 avahi-daemon/main.c | 110 ++++++++++++++++++++++++++++++++++++++++++++
 configure.ac        |   9 ++++
 2 files changed, 119 insertions(+)

diff --git a/avahi-daemon/main.c b/avahi-daemon/main.c
index 884ad2e..460a9d6 100644
--- a/avahi-daemon/main.c
+++ b/avahi-daemon/main.c
@@ -50,6 +50,12 @@
 #endif
 #endif
 
+#ifdef HAVE_KQUEUE
+#include <sys/types.h>
+#include <sys/event.h>
+#include <unistd.h>
+#endif
+
 #include <libdaemon/dfork.h>
 #include <libdaemon/dsignal.h>
 #include <libdaemon/dlog.h>
@@ -691,6 +697,53 @@ static void add_inotify_watches(void) {
 
 #endif
 
+#ifdef HAVE_KQUEUE
+
+#define NUM_WATCHES 2
+
+static int kq = -1;
+static int kfds[NUM_WATCHES];
+static int num_kfds = 0;
+
+static void add_kqueue_watch(const char *dir);
+
+static void add_kqueue_watches(void) {
+	int c = 0;
+
+#ifdef ENABLE_CHROOT
+	c = config.use_chroot;
+#endif
+
+	add_kqueue_watch(c ? "/" : AVAHI_CONFIG_DIR);
+	add_kqueue_watch(c ? "/services" : AVAHI_SERVICE_DIR);
+}
+
+static void add_kqueue_watch(const char *dir) {
+	int fd;
+	struct kevent ev;
+
+	if (kq < 0)
+		return;
+
+	if (num_kfds >= NUM_WATCHES)
+		return;
+
+	fd = open(dir, O_RDONLY);
+	if (fd < 0)
+		return;
+	EV_SET(&ev, fd, EVFILT_VNODE, EV_ADD | EV_ENABLE | EV_CLEAR,
+			NOTE_DELETE | NOTE_EXTEND | NOTE_WRITE | NOTE_RENAME,
+			0, 0);
+	if (kevent(kq, &ev, 1, NULL, 0, NULL) == -1) {
+		close(fd);
+		return;
+	}
+
+	kfds[num_kfds++] = fd;
+}
+
+#endif
+
 static void reload_config(void) {
 
 #ifdef HAVE_INOTIFY
@@ -698,6 +751,10 @@ static void reload_config(void) {
     add_inotify_watches();
 #endif
 
+#ifdef HAVE_KQUEUE
+    add_kqueue_watches();
+#endif
+
 #ifdef ENABLE_CHROOT
     static_service_load(config.use_chroot);
     static_hosts_load(config.use_chroot);
@@ -746,6 +803,31 @@ static void inotify_callback(AvahiWatch *watch, int fd, AVAHI_GCC_UNUSED AvahiWa
 
 #endif
 
+#ifdef HAVE_KQUEUE
+
+static void kqueue_callback(AvahiWatch *watch, int fd, AVAHI_GCC_UNUSED AvahiWatchEvent event, AVAHI_GCC_UNUSED void *userdata) {
+	struct kevent ev;
+	struct timespec nullts = { 0, 0 };
+	int res;
+
+	assert(fd == kq);
+	assert(watch);
+
+	res = kevent(kq, NULL, 0, &ev, 1, &nullts);
+
+	if (res > 0) {
+		/* Sleep for a half-second to avoid potential races
+		 * during install/uninstall. */
+		usleep(500000);
+		avahi_log_info("Files changed, reloading.");
+		reload_config();
+	} else {
+		avahi_log_error("Failed to read kqueue event: %s", avahi_strerror(errno));
+	}
+}
+
+#endif
+
 static void signal_callback(AvahiWatch *watch, AVAHI_GCC_UNUSED int fd, AVAHI_GCC_UNUSED AvahiWatchEvent event, AVAHI_GCC_UNUSED void *userdata) {
     int sig;
     const AvahiPoll *poll_api;
@@ -801,6 +883,10 @@ static int run_server(DaemonConfig *c) {
 #ifdef HAVE_INOTIFY
     AvahiWatch *inotify_watch = NULL;
 #endif
+#ifdef HAVE_KQUEUE
+    int i;
+    AvahiWatch *kqueue_watch = NULL;
+#endif
 
     assert(c);
 
@@ -876,6 +962,19 @@ static int run_server(DaemonConfig *c) {
     }
 #endif
 
+#ifdef HAVE_KQUEUE
+    if ((kq = kqueue()) < 0)
+	    avahi_log_warn( "Failed to initialize kqueue: %s", strerror(errno));
+    else {
+	    add_kqueue_watches();
+
+	    if (!(kqueue_watch = poll_api->watch_new(poll_api, kq, AVAHI_WATCH_IN, kqueue_callback, NULL))) {
+		    avahi_log_error( "Failed to create kqueue watcher");
+		    goto finish;
+	    }
+    }
+#endif
+
     load_resolv_conf();
 #ifdef ENABLE_CHROOT
     static_service_load(config.use_chroot);
@@ -945,6 +1044,17 @@ finish:
     if (inotify_fd >= 0)
         close(inotify_fd);
 #endif
+
+#ifdef HAVE_KQUEUE
+    if (kqueue_watch)
+	poll_api->watch_free(kqueue_watch);
+    if (kq >= 0)
+	close(kq);
+    for (i = 0; i < num_kfds; i++) {
+	if (kfds[i] >= 0)
+	    close(kfds[i]);
+    }
+#endif
     
     if (simple_poll_api) {
         avahi_simple_poll_free(simple_poll_api);
diff --git a/configure.ac b/configure.ac
index 8352d1b..0c205c0 100644
--- a/configure.ac
+++ b/configure.ac
@@ -384,6 +384,15 @@ if test "x$have_inotify" = "xyes" ; then
    AC_DEFINE([HAVE_INOTIFY], 1, [Enable Linux inotify() usage])
 fi
 
+have_kqueue=yes
+AC_CHECK_FUNCS([kqueue],,have_kqueue=no)
+
+AM_CONDITIONAL(HAVE_KQUEUE, test "x$have_kqueue" = "xyes")
+
+if test "x$have_kqueue" = "xyes" ; then
+    AC_DEFINE([HAVE_KQUEUE], 1, [Enable BSD kqueue() usage])
+fi
+
 # Check for pkg-config manually first, as if its not installed the
 # PKG_PROG_PKG_CONFIG macro won't be defined.
 AC_CHECK_PROG(have_pkg_config, pkg-config, yes, no)
-- 
2.39.5