From: Kay Sievers <kay.sievers@vrfy.org>
Date: Tue, 27 Dec 2011 02:49:43 +0000 (+0100)
Subject: move rules dirs to udev context; replace inotify with time-controlled stat()
X-Git-Tag: 176~29
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=commitdiff_plain;h=4f1795cca7060030461c8f3429e5a62f143f74a9

move rules dirs to udev context; replace inotify with time-controlled stat()
---

diff --git a/NEWS b/NEWS
index c01841003..b052257c3 100644
--- a/NEWS
+++ b/NEWS
@@ -1,5 +1,8 @@
 udev 175
 ========
+A writable /run directory (tmpfs) is required now for a fully functional
+udev.
+
 The default 'configure' install locations have changed. Packages for systems
 with the historic / vs. /usr split need to be adapted, otherwise udev will
 be installed in /usr and not work properly. Example configuration options are
diff --git a/libudev/libudev-private.h b/libudev/libudev-private.h
index ffc82cbc6..fed586398 100644
--- a/libudev/libudev-private.h
+++ b/libudev/libudev-private.h
@@ -62,9 +62,7 @@ void udev_log(struct udev *udev,
 	      int priority, const char *file, int line, const char *fn,
 	      const char *format, ...)
 	      __attribute__((format(printf, 6, 7)));
-const char *udev_get_rules_path(struct udev *udev);
-const char *udev_get_run_config_path(struct udev *udev);
-const char *udev_set_run_path(struct udev *udev, const char *path);
+int udev_get_rules_path(struct udev *udev, char **path[], unsigned long long *ts_usec[]);
 struct udev_list_entry *udev_add_property(struct udev *udev, const char *key, const char *value);
 struct udev_list_entry *udev_get_properties_list_entry(struct udev *udev);
 
@@ -195,6 +193,7 @@ uid_t util_lookup_user(struct udev *udev, const char *user);
 gid_t util_lookup_group(struct udev *udev, const char *group);
 int util_resolve_subsys_kernel(struct udev *udev, const char *string,
 				      char *result, size_t maxsize, int read_value);
+unsigned long long ts_usec(const struct timespec *ts);
 unsigned long long now_usec(void);
 
 /* libudev-selinux-private.c */
diff --git a/libudev/libudev-util.c b/libudev/libudev-util.c
index e08349e0f..5369fe734 100644
--- a/libudev/libudev-util.c
+++ b/libudev/libudev-util.c
@@ -552,12 +552,17 @@ uint64_t util_string_bloom64(const char *str)
 
 #define USEC_PER_SEC  1000000ULL
 #define NSEC_PER_USEC 1000ULL
+unsigned long long ts_usec(const struct timespec *ts)
+{
+	return (unsigned long long) ts->tv_sec * USEC_PER_SEC +
+	       (unsigned long long) ts->tv_nsec / NSEC_PER_USEC;
+}
+
 unsigned long long now_usec(void)
 {
 	struct timespec ts;
 
 	if (clock_gettime(CLOCK_MONOTONIC, &ts) != 0)
 		return 0;
-	return (unsigned long long) ts.tv_sec * USEC_PER_SEC +
-	       (unsigned long long) ts.tv_nsec / NSEC_PER_USEC;
+	return ts_usec(&ts);
 }
diff --git a/libudev/libudev.c b/libudev/libudev.c
index 3b3a8e9af..93f2d8f1b 100644
--- a/libudev/libudev.c
+++ b/libudev/libudev.c
@@ -17,6 +17,7 @@
 #include <errno.h>
 #include <string.h>
 #include <ctype.h>
+#include <time.h>
 
 #include "libudev.h"
 #include "libudev-private.h"
@@ -42,8 +43,9 @@ struct udev {
 	void *userdata;
 	char *sys_path;
 	char *dev_path;
-	char *rules_path;
-	char *run_config_path;
+	char *rules_path[4];
+	unsigned long long rules_path_ts[4];
+	int rules_path_count;
 	char *run_path;
 	struct udev_list properties_list;
 	int log_priority;
@@ -218,11 +220,12 @@ UDEV_EXPORT struct udev *udev_new(void)
 				continue;
 			}
 			if (strcmp(key, "udev_run") == 0) {
-				set_value(&udev->run_config_path, val);
+				set_value(&udev->run_path, val);
 				continue;
 			}
 			if (strcmp(key, "udev_rules") == 0) {
-				set_value(&udev->rules_path, val);
+				set_value(&udev->rules_path[0], val);
+				udev->rules_path_count = 1;
 				continue;
 			}
 		}
@@ -255,18 +258,35 @@ UDEV_EXPORT struct udev *udev_new(void)
 		if (set_value(&udev->sys_path, "/sys") == NULL)
 			goto err;
 
-	if (udev->run_config_path == NULL)
-		if (set_value(&udev->run_config_path, "/run/udev") == NULL)
+	if (udev->run_path == NULL)
+		if (set_value(&udev->run_path, "/run/udev") == NULL)
+			goto err;
+
+	if (udev->rules_path[0] == NULL) {
+		/* /usr/lib/udev -- system rules */
+		udev->rules_path[0] = strdup(LIBEXECDIR "/rules.d");
+		if (!udev->rules_path[0])
+			goto err;
+
+		/* /etc/udev -- local administration rules */
+		udev->rules_path[1] = strdup(SYSCONFDIR "/udev/rules.d");
+		if (!udev->rules_path[1])
 			goto err;
 
+		/* /run/udev -- runtime rules */
+		if (asprintf(&udev->rules_path[2], "%s/rules.d", udev->run_path) < 0)
+			goto err;
+
+		udev->rules_path_count = 3;
+	}
+
 	dbg(udev, "context %p created\n", udev);
 	dbg(udev, "log_priority=%d\n", udev->log_priority);
 	dbg(udev, "config_file='%s'\n", config_file);
 	dbg(udev, "dev_path='%s'\n", udev->dev_path);
 	dbg(udev, "sys_path='%s'\n", udev->sys_path);
-	dbg(udev, "run_path='%s'\n", udev->run_config_path);
-	if (udev->rules_path != NULL)
-		dbg(udev, "rules_path='%s'\n", udev->rules_path);
+	dbg(udev, "run_path='%s'\n", udev->run_path);
+	dbg(udev, "rules_path='%s':'%s':'%s'\n", udev->rules_path[0], udev->rules_path[1], udev->rules_path[2]);
 	free(config_file);
 	return udev;
 err:
@@ -310,9 +330,10 @@ UDEV_EXPORT void udev_unref(struct udev *udev)
 	udev_list_cleanup(&udev->properties_list);
 	free(udev->dev_path);
 	free(udev->sys_path);
-	free(udev->rules_path);
+	free(udev->rules_path[0]);
+	free(udev->rules_path[1]);
+	free(udev->rules_path[2]);
 	free(udev->run_path);
-	free(udev->run_config_path);
 	dbg(udev, "context %p released\n", udev);
 	free(udev);
 }
@@ -367,9 +388,12 @@ UDEV_EXPORT void udev_set_log_priority(struct udev *udev, int priority)
 	udev_add_property(udev, "UDEV_LOG", num);
 }
 
-const char *udev_get_rules_path(struct udev *udev)
+int udev_get_rules_path(struct udev *udev, char **path[], unsigned long long *stamp_usec[])
 {
-	return udev->rules_path;
+	*path = udev->rules_path;
+	if (stamp_usec)
+		*stamp_usec = udev->rules_path_ts;
+	return udev->rules_path_count;
 }
 
 /**
@@ -406,11 +430,6 @@ UDEV_EXPORT const char *udev_get_dev_path(struct udev *udev)
 	return udev->dev_path;
 }
 
-const char *udev_get_run_config_path(struct udev *udev)
-{
-	return udev->run_config_path;
-}
-
 /**
  * udev_get_run_path:
  * @udev: udev library context
@@ -421,32 +440,11 @@ const char *udev_get_run_config_path(struct udev *udev)
  **/
 UDEV_EXPORT const char *udev_get_run_path(struct udev *udev)
 {
-	if (udev->run_path != NULL)
-		return udev->run_path;
-
-	/* check if configured path exists */
-	if (access(udev->run_config_path, F_OK) < 0) {
-		char filename[UTIL_PATH_SIZE];
-
-		/* fall back to /dev/.udev if that exists */
-		util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev", NULL);
-		if (access(filename, F_OK) >= 0)
-			if (set_value(&udev->run_path, filename) != NULL)
-				return udev->run_path;
-	}
-
-	/* use default path */
-	set_value(&udev->run_path, udev->run_config_path);
-	if (udev->run_path == NULL)
-		return udev->run_config_path;
+	if (udev == NULL)
+		return NULL;
 	return udev->run_path;
 }
 
-const char *udev_set_run_path(struct udev *udev, const char *path)
-{
-	return set_value(&udev->run_path, path);
-}
-
 struct udev_list_entry *udev_add_property(struct udev *udev, const char *key, const char *value)
 {
 	if (value == NULL) {
diff --git a/udev/udev-builtin-kmod.c b/udev/udev-builtin-kmod.c
index f5b41b1ab..7f2faee26 100644
--- a/udev/udev-builtin-kmod.c
+++ b/udev/udev-builtin-kmod.c
@@ -322,6 +322,7 @@ static void udev_kmod_log(void *data, int priority, const char *file, int line,
 	udev_main_log(data, priority, file, line, fn, format, args);
 }
 
+/* needs to re-instantiate the context after a reload */
 static int builtin_kmod(struct udev_device *dev, int argc, char *argv[], bool test)
 {
 	struct udev *udev = udev_device_get_udev(dev);
@@ -350,6 +351,7 @@ static int builtin_kmod(struct udev_device *dev, int argc, char *argv[], bool te
 	return EXIT_SUCCESS;
 }
 
+/* called at udev startup */
 static int builtin_kmod_init(struct udev *udev)
 {
 	if (ctx)
@@ -365,11 +367,18 @@ static int builtin_kmod_init(struct udev *udev)
 	return 0;
 }
 
-static int builtin_kmod_exit(struct udev *udev)
+/* called on udev shutdown and reload request */
+static void builtin_kmod_exit(struct udev *udev)
 {
 	ctx = kmod_unref(ctx);
 	info(udev, "unload module index\n");
-	return 0;
+}
+
+/* called every couple of seconds during event activity; 'true' if config has changed */
+static bool builtin_kmod_validate(struct udev *udev)
+{
+	info(udev, "validate module index\n");
+	return false;
 }
 
 const struct udev_builtin udev_builtin_kmod = {
@@ -377,6 +386,7 @@ const struct udev_builtin udev_builtin_kmod = {
 	.cmd = builtin_kmod,
 	.init = builtin_kmod_init,
 	.exit = builtin_kmod_exit,
+	.validate = builtin_kmod_validate,
 	.help = "kernel module loader",
 	.run_once = false,
 };
diff --git a/udev/udev-builtin.c b/udev/udev-builtin.c
index cf62d57e2..9804c50fa 100644
--- a/udev/udev-builtin.c
+++ b/udev/udev-builtin.c
@@ -37,30 +37,45 @@ static const struct udev_builtin *builtins[] = {
 int udev_builtin_init(struct udev *udev)
 {
 	unsigned int i;
-
-	for (i = 0; i < ARRAY_SIZE(builtins); i++)
-		if (builtins[i]->init)
-			builtins[i]->init(udev);
-	return 0;
+	int err;
+
+	for (i = 0; i < ARRAY_SIZE(builtins); i++) {
+		if (builtins[i]->init) {
+			err = builtins[i]->init(udev);
+			if (err < 0)
+				break;
+		}
+	}
+	return err;
 }
 
-int udev_builtin_exit(struct udev *udev)
+void udev_builtin_exit(struct udev *udev)
 {
 	unsigned int i;
 
 	for (i = 0; i < ARRAY_SIZE(builtins); i++)
 		if (builtins[i]->exit)
 			builtins[i]->exit(udev);
-	return 0;
 }
 
-int udev_builtin_list(struct udev *udev)
+bool udev_builtin_validate(struct udev *udev)
+{
+	unsigned int i;
+	bool change = false;
+
+	for (i = 0; i < ARRAY_SIZE(builtins); i++)
+		if (builtins[i]->validate)
+			if (builtins[i]->validate(udev))
+				change = true;
+	return change;
+}
+
+void udev_builtin_list(struct udev *udev)
 {
 	unsigned int i;
 
 	for (i = 0; i < ARRAY_SIZE(builtins); i++)
 		fprintf(stderr, "  %-12s %s\n", builtins[i]->name, builtins[i]->help);
-	return 0;
 }
 
 const char *udev_builtin_name(enum udev_builtin_cmd cmd)
diff --git a/udev/udev-rules.c b/udev/udev-rules.c
index aa750219d..411b9d88e 100644
--- a/udev/udev-rules.c
+++ b/udev/udev-rules.c
@@ -1750,6 +1750,7 @@ struct udev_rules *udev_rules_new(struct udev *udev, int resolve_names)
 	struct udev_list file_list;
 	struct udev_list_entry *file_loop;
 	struct token end_token;
+	char **s;
 
 	rules = calloc(1, sizeof(struct udev_rules));
 	if (rules == NULL)
@@ -1791,22 +1792,8 @@ struct udev_rules *udev_rules_new(struct udev *udev, int resolve_names)
 	memset(rules->trie_nodes, 0x00, sizeof(struct trie_node));
 	rules->trie_nodes_cur = 1;
 
-	if (udev_get_rules_path(udev) == NULL) {
-		char filename[UTIL_PATH_SIZE];
-
-		/* /usr/lib/udev -- system rules */
-		add_matching_files(udev, &file_list, LIBEXECDIR "/rules.d", ".rules");
-
-		/* /etc/udev -- local administration rules */
-		add_matching_files(udev, &file_list, SYSCONFDIR "/udev/rules.d", ".rules");
-
-		/* /run/udev -- runtime rules */
-		util_strscpyl(filename, sizeof(filename), udev_get_run_path(udev), "/rules.d", NULL);
-		add_matching_files(udev, &file_list, filename, ".rules");
-	} else {
-		/* custom rules files location for testing */
-		add_matching_files(udev, &file_list, udev_get_rules_path(udev), ".rules");
-	}
+	for (udev_get_rules_path(udev, &s, NULL); *s != NULL; s++)
+		add_matching_files(udev, &file_list, *s, ".rules");
 
 	/* add all filenames to the string buffer */
 	udev_list_entry_foreach(file_loop, udev_list_get_entry(&file_list)) {
diff --git a/udev/udev.h b/udev/udev.h
index 46dafd68e..a289f35c4 100644
--- a/udev/udev.h
+++ b/udev/udev.h
@@ -146,7 +146,8 @@ struct udev_builtin {
 	int (*cmd)(struct udev_device *dev, int argc, char *argv[], bool test);
 	const char *help;
 	int (*init)(struct udev *udev);
-	int (*exit)(struct udev *udev);
+	void (*exit)(struct udev *udev);
+	bool (*validate)(struct udev *udev);
 	bool run_once;
 };
 extern const struct udev_builtin udev_builtin_blkid;
@@ -155,13 +156,13 @@ extern const struct udev_builtin udev_builtin_input_id;
 extern const struct udev_builtin udev_builtin_kmod;
 extern const struct udev_builtin udev_builtin_path_id;
 extern const struct udev_builtin udev_builtin_usb_id;
-int udev_builtin_load(struct udev *udev);
-int udev_builtin_unload(struct udev *udev);
+int udev_builtin_init(struct udev *udev);
+void udev_builtin_exit(struct udev *udev);
 enum udev_builtin_cmd udev_builtin_lookup(const char *command);
 const char *udev_builtin_name(enum udev_builtin_cmd cmd);
 bool udev_builtin_run_once(enum udev_builtin_cmd cmd);
 int udev_builtin_run(struct udev_device *dev, enum udev_builtin_cmd cmd, const char *command, bool test);
-int udev_builtin_list(struct udev *udev);
+void udev_builtin_list(struct udev *udev);
 int udev_builtin_add_property(struct udev_device *dev, bool test, const char *key, const char *val);
 
 /* udev logging */
diff --git a/udev/udevd.c b/udev/udevd.c
index 37eb4ba4b..f810b9431 100644
--- a/udev/udevd.c
+++ b/udev/udevd.c
@@ -736,19 +736,6 @@ static int handle_inotify(struct udev *udev)
 		struct udev_device *dev;
 
 		ev = (struct inotify_event *)(buf + pos);
-		if (ev->len) {
-			const char *s;
-
-			info(udev, "inotify event: %x for %s\n", ev->mask, ev->name);
-			s = strstr(ev->name, ".rules");
-			if (s == NULL)
-				continue;
-			if (strlen(s) != strlen(".rules"))
-				continue;
-			reload = true;
-			continue;
-		}
-
 		dev = udev_watch_lookup(udev, ev->wd);
 		if (dev != NULL) {
 			info(udev, "inotify event: %x for %s\n", ev->mask, udev_device_get_devnode(dev));
@@ -1169,6 +1156,36 @@ static int systemd_fds(struct udev *udev, int *rctrl, int *rnetlink)
 	return 0;
 }
 
+static bool check_rules_timestamp(struct udev *udev)
+{
+	char **p;
+	unsigned long long *stamp_usec;
+	int i, n;
+	bool changed = false;
+
+	n = udev_get_rules_path(udev, &p, &stamp_usec);
+	for (i = 0; i < n; i++) {
+		struct stat stats;
+
+		if (stat(p[i], &stats) < 0)
+			continue;
+
+		if (stamp_usec[i] == ts_usec(&stats.st_mtim))
+			continue;
+
+		/* first check */
+		if (stamp_usec[i] != 0) {
+			info(udev, "reload - timestamp of '%s' changed\n", p[i]);
+			changed = true;
+		}
+
+		/* update timestamp */
+		stamp_usec[i] = ts_usec(&stats.st_mtim);
+	}
+
+	return changed;
+}
+
 int main(int argc, char *argv[])
 {
 	struct udev *udev;
@@ -1191,6 +1208,7 @@ int main(int argc, char *argv[])
 	int fd_worker = -1;
 	struct epoll_event ep_ctrl, ep_inotify, ep_signal, ep_netlink, ep_worker;
 	struct udev_ctrl_connection *ctrl_conn = NULL;
+	char **s;
 	int rc = 1;
 
 	udev = udev_new();
@@ -1202,31 +1220,6 @@ int main(int argc, char *argv[])
 	info(udev, "version %s\n", VERSION);
 	udev_selinux_init(udev);
 
-	/* make sure, that our runtime dir exists and is writable */
-	if (utimensat(AT_FDCWD, udev_get_run_config_path(udev), NULL, 0) < 0) {
-		/* try to create our own subdirectory, do not create parent directories */
-		mkdir(udev_get_run_config_path(udev), 0755);
-
-		if (utimensat(AT_FDCWD, udev_get_run_config_path(udev), NULL, 0) >= 0) {
-			/* directory seems writable now */
-			udev_set_run_path(udev, udev_get_run_config_path(udev));
-		} else {
-			/* fall back to /dev/.udev */
-			char filename[UTIL_PATH_SIZE];
-
-			util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev", NULL);
-			if (udev_set_run_path(udev, filename) == NULL)
-				goto exit;
-			mkdir(udev_get_run_path(udev), 0755);
-			err(udev, "error: runtime directory '%s' not writable, for now falling back to '%s'",
-			    udev_get_run_config_path(udev), udev_get_run_path(udev));
-		}
-	}
-	/* relabel runtime dir only if it resides below /dev */
-	if (strncmp(udev_get_run_path(udev), udev_get_dev_path(udev), strlen(udev_get_dev_path(udev))) == 0)
-		udev_selinux_lsetfilecon(udev, udev_get_run_path(udev), 0755);
-	info(udev, "runtime dir '%s'\n", udev_get_run_path(udev));
-
 	for (;;) {
 		int option;
 
@@ -1469,28 +1462,6 @@ int main(int argc, char *argv[])
 		rc = 4;
 		goto exit;
 	}
-
-	if (udev_get_rules_path(udev) != NULL) {
-		inotify_add_watch(fd_inotify, udev_get_rules_path(udev),
-				  IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
-	} else {
-		char filename[UTIL_PATH_SIZE];
-		struct stat statbuf;
-
-		inotify_add_watch(fd_inotify, LIBEXECDIR "/rules.d",
-				  IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
-		inotify_add_watch(fd_inotify, SYSCONFDIR "/udev/rules.d",
-				  IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
-
-		/* watch dynamic rules directory */
-		util_strscpyl(filename, sizeof(filename), udev_get_run_path(udev), "/rules.d", NULL);
-		if (stat(filename, &statbuf) != 0) {
-			util_create_path(udev, filename);
-			mkdir(filename, 0755);
-		}
-		inotify_add_watch(fd_inotify, filename,
-				  IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
-	}
 	udev_watch_restore(udev);
 
 	/* block and listen to all signals on signalfd */
@@ -1575,6 +1546,7 @@ int main(int argc, char *argv[])
 	udev_list_node_init(&worker_list);
 
 	for (;;) {
+		static unsigned long long last_usec;
 		struct epoll_event ev[8];
 		int fdcount;
 		int timeout;
@@ -1642,6 +1614,24 @@ int main(int argc, char *argv[])
 				is_ctrl = true;
 		}
 
+		/* check for changed config, every 3 seconds at most */
+		if ((now_usec() - last_usec) > 3 * 1000 * 1000) {
+			if (check_rules_timestamp(udev))
+				reload = true;
+			if (udev_builtin_validate(udev))
+				reload = true;
+
+			last_usec = now_usec();
+		}
+
+		/* reload requested, HUP signal received, rules changed, builtin changed */
+		if (reload) {
+			worker_kill(udev, 0);
+			rules = udev_rules_unref(rules);
+			udev_builtin_exit(udev);
+			reload = 0;
+		}
+
 		/* event has finished */
 		if (is_worker)
 			worker_returned(fd_worker);
@@ -1678,7 +1668,7 @@ int main(int argc, char *argv[])
 		if (udev_exit)
 			continue;
 
-		/* device node and rules directory inotify watch */
+		/* device node watch */
 		if (is_inotify)
 			handle_inotify(udev);
 
@@ -1693,14 +1683,6 @@ int main(int argc, char *argv[])
 		 */
 		if (is_ctrl)
 			ctrl_conn = handle_ctrl_msg(udev_ctrl);
-
-		/* rules changed, set by inotify or a HUP signal */
-		if (reload) {
-			worker_kill(udev, 0);
-			rules = udev_rules_unref(rules);
-			udev_builtin_exit(udev);
-			reload = 0;
-		}
 	}
 
 	rc = EXIT_SUCCESS;