[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().

diff --git a/udevd.c b/udevd.c
index 395cdca88baba503e39488c116b587f7196a7025..12fbe1725f07eb29e420f572b581821c94ce616f 100644 (file)
--- 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 657f684e3fb3a861d03f99cde64de1f7bb6e6476..b393a28bf94ad8a55eb646a3d7b7786167450219 100644 (file)
--- 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 19922f3870728cdd394cbfcb6b0827d569c8e59d..7db2378b83b16afc9bda5e8a91cd56b52a721924 100644 (file)
--- 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)