Add HOOK_SVC_LOST to detect lost processes

This patch adds support for the runtime `HOOK_SVC_LOST` and the (very
noisy) *example* plugin `lost.so`.

Customer request.

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

plugins/Makefile.am

@@ -5,12 +5,12 @@ AM_CPPFLAGS        += -DFINIT_FIFO=\"$(fifo)\"
 
 if STATIC
 noinst_LTLIBRARIES  = libplug.la
-libplug_la_SOURCES  = alsa-utils.c bootmisc.c dbus.c hwclock.c		\
-		      initctl.c netlink.c pidfile.c resolvconf.c	\
+libplug_la_SOURCES  = alsa-utils.c bootmisc.c dbus.c hwclock.c			\
+		      initctl.c lost.c netlink.c pidfile.c resolvconf.c		\
 		      time.c tty.c urandom.c x11-common.c
 else
-pkglib_LTLIBRARIES  = alsa-utils.la bootmisc.la dbus.la hwclock.la	\
-		      initctl.la netlink.la pidfile.la resolvconf.la	\
+pkglib_LTLIBRARIES  = alsa-utils.la bootmisc.la dbus.la hwclock.la		\
+		      initctl.la lost.la netlink.la pidfile.la resolvconf.la	\
 		      time.la tty.la urandom.la x11-common.la
 
 # Clean up .la files installed by libtool despite being in -module mode

plugins/lost.c

@@ -0,0 +1,60 @@
+/* Example HOOK_SVC_LOST plugin, very noisy do not use as-is!
+ *
+ * Copyright (c) 2016  Joachim Nilsson <troglobit@gmail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "../finit.h"
+#include "../svc.h"
+#include "../plugin.h"
+
+static void lost_pid(void *arg)
+{
+	pid_t pid = (uintptr_t)arg;
+	svc_t *svc;
+
+	svc = svc_find_by_pid(pid);
+	if (!svc)
+		return;
+
+	FLOG_INFO("Lost PID %u, svc %s", pid, svc->cmd);
+}
+
+static plugin_t plugin = {
+	.name = __FILE__,
+	.hook[HOOK_SVC_LOST] = { .cb  = lost_pid },
+};
+
+PLUGIN_INIT(plugin_init)
+{
+	plugin_register(&plugin);
+}
+
+PLUGIN_EXIT(plugin_exit)
+{
+	plugin_unregister(&plugin);
+}
+
+/**
+ * Local Variables:
+ *  indent-tabs-mode: t
+ *  c-file-style: "linux"
+ * End:
+ */