iwatch: add license+copyright header and initialized guard

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

src/iwatch.c

@@ -1,9 +1,41 @@
+/* inotify watcher for files or directories
+ *
+ * Copyright (c) 2015-2016  Tobias Waldekranz <tobias@waldekranz.com>
+ * Copyright (c) 2016-2021  Joachim Wiberg <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 <errno.h>
 
 #include "finit.h"
 #include "iwatch.h"
 #include "log.h"
 
+/*
+ * iwatch is initialized and used mainly by the pidfile plugin, which is
+ * one of the cornerstones in the condition subsystem.  Other parts of
+ * Finit may use iwatch too, like env: watchers, but are disabled if the
+ * pidfile plugin hasn't called iwatch_init() -- this is by design.
+ */
+static int initialized = 0;
+
 
 int iwatch_init(struct iwatch *iw)
 {
@@ -19,6 +51,7 @@ int iwatch_init(struct iwatch *iw)
 		_pe("inotify_init()");
 		return -1;
 	}
+	initialized = 1;
 
 	return iw->fd;
 }
@@ -35,6 +68,7 @@ void iwatch_exit(struct iwatch *iw)
 	}
 
 	close(iw->fd);
+	initialized = 0;
 }
 
 int iwatch_add(struct iwatch *iw, char *file, uint32_t mask)
@@ -43,6 +77,9 @@ int iwatch_add(struct iwatch *iw, char *file, uint32_t mask)
 	char *path;
 	int wd;
 
+	if (!initialized)
+		return -1;
+
 	_d("Adding new watcher for path %s", file);
 
 	path = strdup(file);
@@ -75,6 +112,9 @@ int iwatch_add(struct iwatch *iw, char *file, uint32_t mask)
 
 int iwatch_del(struct iwatch *iw, struct iwatch_path *iwp)
 {
+	if (!initialized)
+		return -1;
+
 	_d("Removing watcher for removed path %s", iwp->path);
 
 	TAILQ_REMOVE(&iw->iwp_list, iwp, link);
@@ -89,6 +129,9 @@ struct iwatch_path *iwatch_find_by_wd(struct iwatch *iw, int wd)
 {
 	struct iwatch_path *iwp;
 
+	if (!initialized)
+		return NULL;
+
 	TAILQ_FOREACH(iwp, &iw->iwp_list, link) {
 		if (iwp->wd == wd)
 			return iwp;
@@ -101,6 +144,9 @@ struct iwatch_path *iwatch_find_by_path(struct iwatch *iw, const char *path)
 {
 	struct iwatch_path *iwp;
 
+	if (!initialized)
+		return NULL;
+
 	TAILQ_FOREACH(iwp, &iw->iwp_list, link) {
 		if (!strcmp(iwp->path, path))
 			return iwp;