chiark / gitweb /
Add initialization helper for file_handle_union
[elogind.git] / src / libudev / libudev-monitor.c
index 4586b3d4c7bb7528d1da6427c21e22a9bf3c826e..da2b63473f3aebe5a83b46202eea3a13077e34c1 100644 (file)
@@ -96,7 +96,7 @@ static struct udev_monitor *udev_monitor_new(struct udev *udev)
 {
         struct udev_monitor *udev_monitor;
 
-        udev_monitor = calloc(1, sizeof(struct udev_monitor));
+        udev_monitor = new0(struct udev_monitor, 1);
         if (udev_monitor == NULL)
                 return NULL;
         udev_monitor->refcount = 1;
@@ -108,25 +108,25 @@ static struct udev_monitor *udev_monitor_new(struct udev *udev)
 
 /* we consider udev running when /dev is on devtmpfs */
 static bool udev_has_devtmpfs(struct udev *udev) {
-        struct file_handle *h;
-        int mount_id;
+
+        union file_handle_union h = FILE_HANDLE_INIT;
         _cleanup_fclose_ FILE *f = NULL;
         char line[LINE_MAX], *e;
+        int mount_id;
         int r;
 
-        h = alloca(MAX_HANDLE_SZ);
-
-        r = name_to_handle_at(AT_FDCWD, "/dev", h, &mount_id, 0);
-        if (r < 0)
+        r = name_to_handle_at(AT_FDCWD, "/dev", &h.handle, &mount_id, 0);
+        if (r < 0) {
+                if (errno != EOPNOTSUPP)
+                        log_debug_errno(errno, "name_to_handle_at on /dev: %m");
                 return false;
-
+        }
 
         f = fopen("/proc/self/mountinfo", "re");
         if (!f)
                 return false;
 
         FOREACH_LINE(line, f, return false) {
-                _cleanup_free_ char *opts = NULL;
                 int mid;
 
                 if (sscanf(line, "%i", &mid) != 1)
@@ -147,21 +147,6 @@ static bool udev_has_devtmpfs(struct udev *udev) {
         return false;
 }
 
-/* we consider udev running when we have running udev service */
-static bool udev_has_service(struct udev *udev) {
-        struct udev_queue *queue;
-        bool active;
-
-        queue = udev_queue_new(udev);
-        if (!queue)
-                return false;
-
-        active = udev_queue_get_udev_is_active(queue);
-        udev_queue_unref(queue);
-
-        return active;
-}
-
 struct udev_monitor *udev_monitor_new_from_netlink_fd(struct udev *udev, const char *name, int fd)
 {
         struct udev_monitor *udev_monitor;
@@ -172,27 +157,29 @@ struct udev_monitor *udev_monitor_new_from_netlink_fd(struct udev *udev, const c
 
         if (name == NULL)
                 group = UDEV_MONITOR_NONE;
-        else if (streq(name, "udev"))
-                group = UDEV_MONITOR_UDEV;
-        else if (streq(name, "kernel"))
+        else if (streq(name, "udev")) {
+                /*
+                 * We do not support subscribing to uevents if no instance of
+                 * udev is running. Uevents would otherwise broadcast the
+                 * processing data of the host into containers, which is not
+                 * desired.
+                 *
+                 * Containers will currently not get any udev uevents, until
+                 * a supporting infrastructure is available.
+                 *
+                 * We do not set a netlink multicast group here, so the socket
+                 * will not receive any messages.
+                 */
+                if (access("/run/udev/control", F_OK) < 0 && !udev_has_devtmpfs(udev)) {
+                        log_debug("the udev service seems not to be active, disable the monitor");
+                        group = UDEV_MONITOR_NONE;
+                } else
+                        group = UDEV_MONITOR_UDEV;
+        } else if (streq(name, "kernel"))
                 group = UDEV_MONITOR_KERNEL;
         else
                 return NULL;
 
-        /*
-         * We do not support subscribing to uevents if no instance of udev
-         * is running. Uevents would otherwise broadcast the processing data
-         * of the host into containers, which is not acceptable. Containers
-         * will currently just not get any uevents.
-         *
-         * We clear the netlink multicast group here, so the socket will
-         * not receive any messages.
-         */
-        if (!udev_has_service(udev) && !udev_has_devtmpfs(udev)) {
-                udev_dbg(udev, "udev seems not to be active, disable the monitor\n");
-                group = 0;
-        }
-
         udev_monitor = udev_monitor_new(udev);
         if (udev_monitor == NULL)
                 return NULL;
@@ -200,7 +187,7 @@ struct udev_monitor *udev_monitor_new_from_netlink_fd(struct udev *udev, const c
         if (fd < 0) {
                 udev_monitor->sock = socket(PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC|SOCK_NONBLOCK, NETLINK_KOBJECT_UEVENT);
                 if (udev_monitor->sock == -1) {
-                        udev_err(udev, "error getting socket: %m\n");
+                        log_debug_errno(errno, "error getting socket: %m");
                         free(udev_monitor);
                         return NULL;
                 }
@@ -290,7 +277,7 @@ _public_ int udev_monitor_filter_update(struct udev_monitor *udev_monitor)
             udev_list_get_entry(&udev_monitor->filter_tag_list) == NULL)
                 return 0;
 
-        memset(ins, 0x00, sizeof(ins));
+        memzero(ins, sizeof(ins));
         i = 0;
 
         /* load magic in A */
@@ -370,7 +357,7 @@ _public_ int udev_monitor_filter_update(struct udev_monitor *udev_monitor)
         bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff);
 
         /* install filter */
-        memset(&filter, 0x00, sizeof(filter));
+        memzero(&filter, sizeof(filter));
         filter.len = i;
         filter.filter = ins;
         err = setsockopt(udev_monitor->sock, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter));
@@ -417,12 +404,15 @@ _public_ int udev_monitor_enable_receiving(struct udev_monitor *udev_monitor)
                 if (err == 0)
                         udev_monitor->snl.nl.nl_pid = snl.nl.nl_pid;
         } else {
-                udev_err(udev_monitor->udev, "bind failed: %m\n");
+                log_debug_errno(errno, "bind failed: %m");
                 return -errno;
         }
 
         /* enable receiving of sender credentials */
-        setsockopt(udev_monitor->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
+        err = setsockopt(udev_monitor->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
+        if (err < 0)
+                log_debug_errno(errno, "setting SO_PASSCRED failed: %m");
+
         return 0;
 }
 
@@ -589,7 +579,10 @@ _public_ struct udev_device *udev_monitor_receive_device(struct udev_monitor *ud
         struct cmsghdr *cmsg;
         union sockaddr_union snl;
         struct ucred *cred;
-        char buf[8192];
+        union {
+                struct udev_monitor_netlink_header nlh;
+                char raw[8192];
+        } buf;
         ssize_t buflen;
         ssize_t bufpos;
 
@@ -598,7 +591,7 @@ retry:
                 return NULL;
         iov.iov_base = &buf;
         iov.iov_len = sizeof(buf);
-        memset (&smsg, 0x00, sizeof(struct msghdr));
+        memzero(&smsg, sizeof(struct msghdr));
         smsg.msg_iov = &iov;
         smsg.msg_iovlen = 1;
         smsg.msg_control = cred_msg;
@@ -609,12 +602,12 @@ retry:
         buflen = recvmsg(udev_monitor->sock, &smsg, 0);
         if (buflen < 0) {
                 if (errno != EINTR)
-                        udev_dbg(udev_monitor->udev, "unable to receive message\n");
+                        log_debug("unable to receive message");
                 return NULL;
         }
 
-        if (buflen < 32 || (size_t)buflen >= sizeof(buf)) {
-                udev_dbg(udev_monitor->udev, "invalid message length\n");
+        if (buflen < 32 || (smsg.msg_flags & MSG_TRUNC)) {
+                log_debug("invalid message length");
                 return NULL;
         }
 
@@ -622,12 +615,12 @@ retry:
                 /* unicast message, check if we trust the sender */
                 if (udev_monitor->snl_trusted_sender.nl.nl_pid == 0 ||
                     snl.nl.nl_pid != udev_monitor->snl_trusted_sender.nl.nl_pid) {
-                        udev_dbg(udev_monitor->udev, "unicast netlink message ignored\n");
+                        log_debug("unicast netlink message ignored");
                         return NULL;
                 }
         } else if (snl.nl.nl_groups == UDEV_MONITOR_KERNEL) {
                 if (snl.nl.nl_pid > 0) {
-                        udev_dbg(udev_monitor->udev, "multicast kernel netlink message from pid %d ignored\n",
+                        log_debug("multicast kernel netlink message from pid %d ignored",
                              snl.nl.nl_pid);
                         return NULL;
                 }
@@ -635,13 +628,13 @@ retry:
 
         cmsg = CMSG_FIRSTHDR(&smsg);
         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
-                udev_dbg(udev_monitor->udev, "no sender credentials received, message ignored\n");
+                log_debug("no sender credentials received, message ignored");
                 return NULL;
         }
 
         cred = (struct ucred *)CMSG_DATA(cmsg);
         if (cred->uid != 0) {
-                udev_dbg(udev_monitor->udev, "sender uid=%d, message ignored\n", cred->uid);
+                log_debug("sender uid=%d, message ignored", cred->uid);
                 return NULL;
         }
 
@@ -649,38 +642,35 @@ retry:
         if (udev_device == NULL)
                 return NULL;
 
-        if (memcmp(buf, "libudev", 8) == 0) {
-                struct udev_monitor_netlink_header *nlh;
-
+        if (memcmp(buf.raw, "libudev", 8) == 0) {
                 /* udev message needs proper version magic */
-                nlh = (struct udev_monitor_netlink_header *) buf;
-                if (nlh->magic != htonl(UDEV_MONITOR_MAGIC)) {
-                        udev_err(udev_monitor->udev, "unrecognized message signature (%x != %x)\n",
-                                 nlh->magic, htonl(UDEV_MONITOR_MAGIC));
+                if (buf.nlh.magic != htonl(UDEV_MONITOR_MAGIC)) {
+                        log_debug("unrecognized message signature (%x != %x)",
+                                 buf.nlh.magic, htonl(UDEV_MONITOR_MAGIC));
                         udev_device_unref(udev_device);
                         return NULL;
                 }
-                if (nlh->properties_off+32 > (size_t)buflen) {
+                if (buf.nlh.properties_off+32 > (size_t)buflen) {
                         udev_device_unref(udev_device);
                         return NULL;
                 }
 
-                bufpos = nlh->properties_off;
+                bufpos = buf.nlh.properties_off;
 
                 /* devices received from udev are always initialized */
                 udev_device_set_is_initialized(udev_device);
         } else {
                 /* kernel message with header */
-                bufpos = strlen(buf) + 1;
+                bufpos = strlen(buf.raw) + 1;
                 if ((size_t)bufpos < sizeof("a@/d") || bufpos >= buflen) {
-                        udev_dbg(udev_monitor->udev, "invalid message length\n");
+                        log_debug("invalid message length");
                         udev_device_unref(udev_device);
                         return NULL;
                 }
 
                 /* check message header */
-                if (strstr(buf, "@/") == NULL) {
-                        udev_dbg(udev_monitor->udev, "unrecognized message header\n");
+                if (strstr(buf.raw, "@/") == NULL) {
+                        log_debug("unrecognized message header");
                         udev_device_unref(udev_device);
                         return NULL;
                 }
@@ -692,7 +682,7 @@ retry:
                 char *key;
                 size_t keylen;
 
-                key = &buf[bufpos];
+                key = &buf.raw[bufpos];
                 keylen = strlen(key);
                 if (keylen == 0)
                         break;
@@ -701,7 +691,7 @@ retry:
         }
 
         if (udev_device_add_property_from_string_parse_finish(udev_device) < 0) {
-                udev_dbg(udev_monitor->udev, "missing values, invalid device\n");
+                log_debug("missing values, invalid device");
                 udev_device_unref(udev_device);
                 return NULL;
         }
@@ -743,7 +733,7 @@ int udev_monitor_send_device(struct udev_monitor *udev_monitor,
                 return -EINVAL;
 
         /* add versioned header */
-        memset(&nlh, 0x00, sizeof(struct udev_monitor_netlink_header));
+        memzero(&nlh, sizeof(struct udev_monitor_netlink_header));
         memcpy(nlh.prefix, "libudev", 8);
         nlh.magic = htonl(UDEV_MONITOR_MAGIC);
         nlh.header_size = sizeof(struct udev_monitor_netlink_header);
@@ -770,7 +760,7 @@ int udev_monitor_send_device(struct udev_monitor *udev_monitor,
         iov[1].iov_base = (char *)buf;
         iov[1].iov_len = blen;
 
-        memset(&smsg, 0x00, sizeof(struct msghdr));
+        memzero(&smsg, sizeof(struct msghdr));
         smsg.msg_iov = iov;
         smsg.msg_iovlen = 2;
         /*
@@ -785,7 +775,7 @@ int udev_monitor_send_device(struct udev_monitor *udev_monitor,
                 smsg.msg_name = &udev_monitor->snl_destination;
         smsg.msg_namelen = sizeof(struct sockaddr_nl);
         count = sendmsg(udev_monitor->sock, &smsg, 0);
-        udev_dbg(udev_monitor->udev, "passed %zi bytes to netlink monitor %p\n", count, udev_monitor);
+        log_debug("passed %zi bytes to netlink monitor %p", count, udev_monitor);
         return count;
 }