[PATCH] pass the whole event environment to udevd

Make _all_ hotplug variables available to the forked udev,
the udev callouts and the udev dev.d/ scripts. We put the
whole environment into a buffer and send it over the udevd
socket. udevd recreates *envp[] and passes it to the exec().

3 files changed, 112 insertions, 91 deletions

diff --git a/udevd.c b/udevd.c
index 395cdca88b..12fbe1725f 100644
--- a/udevd.c
+++ b/udevd.c
@@ -86,16 +86,6 @@ static void msg_dump_queue(void)
 #endif
 }
 
-static struct hotplug_msg *msg_create(void)
-{
-	struct hotplug_msg *new_msg;
-
-	new_msg = malloc(sizeof(struct hotplug_msg));
-	if (new_msg == NULL)
-		dbg("error malloc");
-	return new_msg;
-}
-
 static void run_queue_delete(struct hotplug_msg *msg)
 {
 	list_del(&msg->list);
@@ -132,22 +122,12 @@ static void msg_queue_insert(struct hotplug_msg *msg)
 static void udev_run(struct hotplug_msg *msg)
 {
 	pid_t pid;
-	char action[ACTION_SIZE];
-	char devpath[DEVPATH_SIZE];
-	char seqnum[SEQNUM_SIZE];
-	char *env[] = { action, devpath, seqnum, NULL };
-
-	snprintf(action, ACTION_SIZE-1, "ACTION=%s", msg->action);
-	action[ACTION_SIZE-1] = '\0';
-	snprintf(devpath, DEVPATH_SIZE-1, "DEVPATH=%s", msg->devpath);
-	devpath[DEVPATH_SIZE-1] = '\0';
-	sprintf(seqnum, "SEQNUM=%llu", msg->seqnum);
 
 	pid = fork();
 	switch (pid) {
 	case 0:
 		/* child */
-		execle(udev_bin, "udev", msg->subsystem, NULL, env);
+		execle(udev_bin, "udev", msg->subsystem, NULL, msg->envp);
 		dbg("exec of child failed");
 		_exit(1);
 		break;
@@ -245,24 +225,23 @@ recheck:
 }
 
 /* receive the msg, do some basic sanity checks, and queue it */
-static void handle_msg(int sock)
+static void handle_udevsend_msg(int sock)
 {
+	static struct udevsend_msg usend_msg;
 	struct hotplug_msg *msg;
-	int retval;
+	int bufpos;
+	int i;
+	ssize_t size;
 	struct msghdr smsg;
 	struct cmsghdr *cmsg;
 	struct iovec iov;
 	struct ucred *cred;
 	char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
+	int envbuf_size;
 
-	msg = msg_create();
-	if (msg == NULL) {
-		dbg("unable to store message");
-		return;
-	}
-
-	iov.iov_base = msg;
-	iov.iov_len = sizeof(struct hotplug_msg);
+	memset(&usend_msg, 0x00, sizeof(struct udevsend_msg));
+	iov.iov_base = &usend_msg;
+	iov.iov_len = sizeof(struct udevsend_msg);
 
 	memset(&smsg, 0x00, sizeof(struct msghdr));
 	smsg.msg_iov = &iov;
@@ -270,8 +249,8 @@ static void handle_msg(int sock)
 	smsg.msg_control = cred_msg;
 	smsg.msg_controllen = sizeof(cred_msg);
 
-	retval = recvmsg(sock, &smsg, 0);
-	if (retval <  0) {
+	size = recvmsg(sock, &smsg, 0);
+	if (size <  0) {
 		if (errno != EINTR)
 			dbg("unable to receive message");
 		return;
@@ -281,18 +260,51 @@ static void handle_msg(int sock)
 
 	if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 		dbg("no sender credentials received, message ignored");
-		goto skip;
+		goto exit;
 	}
 
 	if (cred->uid != 0) {
 		dbg("sender uid=%i, message ignored", cred->uid);
-		goto skip;
+		goto exit;
+	}
+
+	if (strncmp(usend_msg.magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
+		dbg("message magic '%s' doesn't match, ignore it", usend_msg.magic);
+		goto exit;
 	}
 
-	if (strncmp(msg->magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
-		dbg("message magic '%s' doesn't match, ignore it", msg->magic);
-		goto skip;
+	envbuf_size = size - offsetof(struct udevsend_msg, envbuf);
+	dbg("envbuf_size=%i", envbuf_size);
+	msg = malloc(sizeof(struct hotplug_msg) + envbuf_size);
+	memset(msg, 0x00, sizeof(struct hotplug_msg) + envbuf_size);
+
+	/* copy environment buffer and reconstruct envp */
+	memcpy(msg->envbuf, usend_msg.envbuf, envbuf_size);
+	bufpos = 0;
+	for (i = 0; (bufpos < envbuf_size) && (i < HOTPLUG_NUM_ENVP-1); i++) {
+		int keylen;
+		char *key;
+
+		key = &msg->envbuf[bufpos];
+		keylen = strlen(key);
+		msg->envp[i] = key;
+		bufpos += keylen + 1;
+		dbg("add '%s' to msg.envp[%i]", msg->envp[i], i);
+
+		/* remember some keys for further processing */
+		if (strncmp(key, "ACTION=", 7) == 0)
+			msg->action = &key[7];
+
+		if (strncmp(key, "DEVPATH=", 8) == 0)
+			msg->devpath = &key[8];
+
+		if (strncmp(key, "SUBSYSTEM=", 10) == 0)
+			msg->subsystem = &key[10];
+
+		if (strncmp(key, "SEQNUM=", 7) == 0)
+			msg->seqnum = strtoull(&key[7], NULL, 10);
 	}
+	msg->envp[i] = NULL;
 
 	/* if no seqnum is given, we move straight to exec queue */
 	if (msg->seqnum == 0) {
@@ -301,10 +313,8 @@ static void handle_msg(int sock)
 	} else {
 		msg_queue_insert(msg);
 	}
-	return;
 
-skip:
-	free(msg);
+exit:
 	return;
 }
 
@@ -511,7 +521,7 @@ int main(int argc, char *argv[], char *envp[])
 		}
 
 		if (FD_ISSET(ssock, &workreadfds))
-			handle_msg(ssock);
+			handle_udevsend_msg(ssock);
 
 		if (FD_ISSET(pipefds[0], &workreadfds))
 			user_sighandler();
diff --git a/udevd.h b/udevd.h
index 657f684e3f..b393a28bf9 100644
--- a/udevd.h
+++ b/udevd.h
@@ -30,14 +30,23 @@
 #define SEND_WAIT_MAX_SECONDS		3
 #define SEND_WAIT_LOOP_PER_SECOND	10
 
+/* environment buffer, should match the kernel's size in lib/kobject_uevent.h */
+#define HOTPLUG_BUFFER_SIZE		1024
+#define HOTPLUG_NUM_ENVP		32
 
-struct hotplug_msg {
+struct udevsend_msg {
 	char magic[20];
+	char envbuf[HOTPLUG_BUFFER_SIZE];
+};
+
+struct hotplug_msg {
 	struct list_head list;
 	pid_t pid;
-	unsigned long long seqnum;
 	long queue_time;
-	char action[ACTION_SIZE];
-	char devpath[DEVPATH_SIZE];
-	char subsystem[SUBSYSTEM_SIZE];
+	char *action;
+	char *devpath;
+	char *subsystem;
+	unsigned long long seqnum;
+	char *envp[HOTPLUG_NUM_ENVP];
+	char envbuf[];
 };
diff --git a/udevsend.c b/udevsend.c
index 19922f3870..7db2378b83 100644
--- a/udevsend.c
+++ b/udevsend.c
@@ -70,7 +70,7 @@ static int start_daemon(void)
 			chdir("/");
 			execl(UDEVD_BIN, "udevd", NULL);
 			dbg("exec of daemon failed");
-			exit(1);
+			_exit(1);
 		case -1:
 			dbg("fork of daemon failed");
 			return -1;
@@ -107,51 +107,29 @@ static void run_udev(const char *subsystem)
 	}
 }
 
-int main(int argc, char* argv[])
+int main(int argc, char *argv[], char *envp[])
 {
-	struct hotplug_msg msg;
-	char *action;
-	char *devpath;
-	char *subsystem;
-	char *seqnum;
-	unsigned long long seq;
-	int retval = 1;
+	static struct udevsend_msg usend_msg;
+	int usend_msg_len;
+	int i;
 	int loop;
-	int sock = -1;
 	struct sockaddr_un saddr;
 	socklen_t addrlen;
+	const char *subsystem_argv;
+	int subsystem_env = 0;
+	int bufpos = 0;
+	int retval = 1;
+	int sock = -1;
 	int started_daemon = 0;
 
 	logging_init("udevsend");
 	dbg("version %s", UDEV_VERSION);
 
-	subsystem = get_subsystem(argv[1]);
-	if (subsystem == NULL) {
+	subsystem_argv = argv[1];
+	if (subsystem_argv == NULL) {
 		dbg("no subsystem");
 		goto exit;
 	}
-	dbg("subsystem = '%s'", subsystem);
-
-	devpath = get_devpath();
-	if (devpath == NULL) {
-		dbg("no devpath");
-		goto exit;
-	}
-	dbg("DEVPATH = '%s'", devpath);
-
-	action = get_action();
-	if (action == NULL) {
-		dbg("no action");
-		goto exit;
-	}
-	dbg("ACTION = '%s'", action);
-
-	seqnum = get_seqnum();
-	if (seqnum == NULL)
-		seq = 0;
-	else
-		seq = strtoull(seqnum, NULL, 10);
-	dbg("SEQNUM = '%llu'", seq);
 
 	sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 	if (sock == -1) {
@@ -167,25 +145,49 @@ int main(int argc, char* argv[])
 	strcpy(&saddr.sun_path[1], UDEVD_SOCK_PATH);
 	addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
 
-	memset(&msg, 0x00, sizeof(struct hotplug_msg));
-	strcpy(msg.magic, UDEV_MAGIC);
-	msg.seqnum = seq;
-	strfieldcpy(msg.action, action);
-	strfieldcpy(msg.devpath, devpath);
-	strfieldcpy(msg.subsystem, subsystem);
+	memset(&usend_msg, 0x00, sizeof(struct udevsend_msg));
+
+	strcpy(usend_msg.magic, UDEV_MAGIC);
+
+	/* copy all keys to send buffer */
+	for (i = 0; envp[i]; i++) {
+		const char *key;
+		int keylen;
+
+		key = envp[i];
+		keylen = strlen(key);
+		if (bufpos + keylen >= HOTPLUG_BUFFER_SIZE-1) {
+			dbg("environment buffer too small, probably not called by the kernel");
+			continue;
+		}
+
+		/* older kernels do not have the SUBSYSTEM in the environment */
+		if (strncmp(key, "SUBSYSTEM=", 10) == 0)
+			subsystem_env = 1;
+
+		dbg("add '%s' to env[%i] buffer", key, i);
+		strcpy(&usend_msg.envbuf[bufpos], key);
+		bufpos += keylen + 1;
+	}
+	if (!subsystem_env) {
+		bufpos += sprintf(&usend_msg.envbuf[bufpos], "SUBSYSTEM=%s", subsystem_argv) + 1;
+		dbg("add 'SUBSYSTEM=%s' to env[%i] buffer from argv", subsystem_argv, i);
+	}
+
+	usend_msg_len = offsetof(struct udevsend_msg, envbuf) + bufpos;
+	dbg("usend_msg_len=%i", usend_msg_len);
 
 	/* If we can't send, try to start daemon and resend message */
 	loop = SEND_WAIT_MAX_SECONDS * SEND_WAIT_LOOP_PER_SECOND;
 	while (--loop) {
-		retval = sendto(sock, &msg, sizeof(struct hotplug_msg), 0,
-				(struct sockaddr *)&saddr, addrlen);
+		retval = sendto(sock, &usend_msg, usend_msg_len, 0, (struct sockaddr *)&saddr, addrlen);
 		if (retval != -1) {
 			retval = 0;
 			goto exit;
 		}
 
 		if (errno != ECONNREFUSED) {
-			dbg("error sending message");
+			dbg("error sending message (%s)", strerror(errno));
 			goto fallback;
 		}
 
@@ -206,7 +208,7 @@ int main(int argc, char* argv[])
 
 fallback:
 	info("unable to connect to event daemon, try to call udev directly");
-	run_udev(subsystem);
+	run_udev(subsystem_argv);
 
 exit:
 	if (sock != -1)