move udev-rules parsing into the daemon

[Kay Sievers <kay.sievers@vrfy.org>]

[-- Attachment #1: Type: text/plain, Size: 700 bytes --]

Here we move the parsed rules into the udev daemon, which will no longer
execute the udev binary. This saves us the rule parsing, cause the
parsed rules will be inherited from the daemon process, which will
fork() a child which imediately becomes the event process without doing
an exec(). It's basically a retry of this old patch:
  http://marc.theaimsgroup.com/?l=linux-hotplug-devel&m=109814301613236&w=2

Changes to /etc/udev/rules.d/* will automatically recognized and will cause
a reload of the rules, also the usual -HUP should work.

Would be nice if someone brave enough can give it a try, we want to put
that upstream if it works as expected. The patch applies on top of v064.

Thanks,
Kay

[-- Attachment #2: udevd-noexec-12.patch --]
[-- Type: text/plain, Size: 5399 bytes --]

diff --git a/RELEASE-NOTES b/RELEASE-NOTES
--- a/RELEASE-NOTES
+++ b/RELEASE-NOTES
@@ -1,3 +1,21 @@
+udev 065
+========
+
+
+udev 064
+========
+Mostly bugfixes and see ChangeLog.
+
+The test for the existence of an environment value should be
+switched from:
+  ENV{KEY}=="*" to ENV{KEY}=="?*"
+cause "*" will not fail anymore, if the key does not exist or
+is empty.
+
+udev 063
+========
+Bugfixes and a few tweaks described in the ChangeLog.
+
 udev 062
 ========
 Mostly a Bugfix release.
diff --git a/udevcontrol.c b/udevcontrol.c
--- a/udevcontrol.c
+++ b/udevcontrol.c
@@ -97,7 +97,9 @@ int main(int argc, char *argv[], char *e
 		usend_msg.type = UDEVD_SET_MAX_CHILDS;
 		*intval = atoi(val);
 		info("send max_childs=%i", *intval);
-	} else {
+	} else if (!strcmp(argv[1], "reload_rules"))
+		usend_msg.type = UDEVD_RELOAD_RULES;
+	else {
 		err("error parsing command\n");
 		goto exit;
 	}
diff --git a/udevd.c b/udevd.c
--- a/udevd.c
+++ b/udevd.c
@@ -45,6 +45,7 @@
 #include "udev_libc_wrapper.h"
 #include "udev.h"
 #include "udev_version.h"
+#include "udev_rules.h"
 #include "udev_utils.h"
 #include "udevd.h"
 #include "logging.h"
@@ -54,6 +55,7 @@
 #endif
 
 /* global variables*/
+struct udev_rules rules;
 static int udevd_sock;
 static int uevent_netlink_sock;
 static pid_t sid;
@@ -65,6 +67,7 @@ static volatile int sig_flag;
 static int init_phase = 1;
 static int run_exec_q;
 static int stop_exec_q;
+static int reload_config;
 
 static LIST_HEAD(msg_list);
 static LIST_HEAD(exec_list);
@@ -167,10 +170,54 @@ static void msg_queue_insert(struct ueve
 	return;
 }
 
+static void asmlinkage udev_event_sig_handler(int signum)
+{
+	if (signum == SIGALRM)
+		exit(1);
+}
+
+static int udev_event_process(struct uevent_msg *msg)
+{
+	struct sigaction act;
+	struct udevice udev;
+	struct name_entry *name_loop;
+	int i;
+	int retval;
+
+	logging_init("udevd-event");
+
+	/* set signal handlers */
+	memset(&act, 0x00, sizeof(act));
+	act.sa_handler = (void (*)(int)) udev_event_sig_handler;
+	sigemptyset (&act.sa_mask);
+	act.sa_flags = 0;
+	sigaction(SIGALRM, &act, NULL);
+
+	/* trigger timeout to prevent hanging processes */
+	alarm(UDEV_ALARM_TIMEOUT);
+
+	/* reconstruct env */
+	for (i = 0; msg->envp[i]; i++)
+		putenv(msg->envp[i]);
+
+	udev_init_device(&udev, msg->devpath, msg->subsystem, msg->action);
+	retval = udev_process_event(&rules, &udev);
+
+	/* run programs collected by RUN-key*/
+	if (!retval) {
+		list_for_each_entry(name_loop, &udev.run_list, node)
+			execute_program(name_loop->name, udev.subsystem, NULL, 0, NULL);
+	}
+
+	udev_cleanup_device(&udev);
+	logging_close();
+
+	return 0;
+}
+
 /* forks event and removes event from run queue when finished */
 static void udev_event_fork(struct uevent_msg *msg)
 {
-	char *const argv[] = { "udev", msg->subsystem, NULL };
 	pid_t pid;
 	struct sysinfo info;
 
@@ -183,9 +230,9 @@ static void udev_event_fork(struct ueven
 		close(udevd_sock);
 		logging_close();
 		setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
-		execve(udev_bin, argv, msg->envp);
-		err("exec of child failed");
-		_exit(1);
+
+		udev_event_process(msg);
+		exit(0);
 	case -1:
 		err("fork of child failed");
 		msg_queue_delete(msg);
@@ -580,6 +627,11 @@ static struct uevent_msg *get_udevd_msg(
 		info("udevd message (UDEVD_SET_MAX_CHILDS) received, max_childs=%i", *intval);
 		max_childs = *intval;
 		break;
+	case UDEVD_RELOAD_RULES:
+		info("udevd message (RELOAD_RULES) received");
+		udev_rules_close(&rules);
+		udev_rules_init(&rules, 1);
+		break;
 	default:
 		dbg("unknown message type");
 	}
@@ -650,16 +702,17 @@ static void asmlinkage sig_handler(int s
 		case SIGALRM:
 			/* set flag, then write to pipe if needed */
 			run_msg_q = 1;
-			goto do_write;
 			break;
 		case SIGCHLD:
 			/* set flag, then write to pipe if needed */
 			sigchilds_waiting = 1;
-			goto do_write;
+			break;
+		case SIGHUP:
+		case SIGIO:
+			reload_config = 1;
 			break;
 	}
 
-do_write:
 	/* if pipe is empty, write to pipe to force select to return
 	 * immediately when it gets called
 	 */
@@ -787,6 +840,24 @@ static int init_uevent_netlink_sock(void
 	return 0;
 }
 
+static int watch_directory(const char *dir)
+{
+	int fd;
+
+	fd = open(dir, O_RDONLY);
+	if (fd < 0) {
+		err("could not open '%s' to watch it", dir);
+		return -1;
+	}
+	if (fcntl(fd, F_NOTIFY, DN_MODIFY | DN_CREATE | DN_DELETE | DN_MULTISHOT) == -1) {
+		err("could not set dnotify on '%s'", dir);
+		return -1;
+		close(fd);
+	}
+
+	return 0;
+}
+
 int main(int argc, char *argv[], char *envp[])
 {
 	int maxsockplus;
@@ -891,6 +962,11 @@ int main(int argc, char *argv[], char *e
 	sigaction(SIGTERM, &act, NULL);
 	sigaction(SIGALRM, &act, NULL);
 	sigaction(SIGCHLD, &act, NULL);
+	sigaction(SIGHUP, &act, NULL);
+	sigaction(SIGIO, &act, NULL);
+
+	udev_rules_init(&rules, 1);
+	watch_directory(udev_rules_filename);
 
 	if (init_uevent_netlink_sock() < 0) {
 		dbg("uevent socket not available");
@@ -1010,6 +1086,12 @@ int main(int argc, char *argv[], char *e
 			if (!stop_exec_q)
 				exec_queue_manager();
 		}
+
+		if (reload_config) {
+			reload_config = 0;
+			udev_rules_close(&rules);
+			udev_rules_init(&rules, 1);
+		}
 	}
 
 exit:
diff --git a/udevd.h b/udevd.h
--- a/udevd.h
+++ b/udevd.h
@@ -54,6 +54,7 @@ enum udevd_msg_type {
 	UDEVD_START_EXEC_QUEUE,
 	UDEVD_SET_LOG_LEVEL,
 	UDEVD_SET_MAX_CHILDS,
+	UDEVD_RELOAD_RULES,
 };