X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Flibudev%2Flibudev-monitor.c;h=da2b63473f3aebe5a83b46202eea3a13077e34c1;hp=b02ea8808cf949a41de9caca803dba7e7b859f01;hb=2695c5c44e028d1bc07404baf3357e5a6017fc57;hpb=f274ece0f76b5709408821e317e87aef76123db6

diff --git a/src/libudev/libudev-monitor.c b/src/libudev/libudev-monitor.c
index b02ea8808..da2b63473 100644
--- a/src/libudev/libudev-monitor.c
+++ b/src/libudev/libudev-monitor.c
@@ -35,6 +35,7 @@
 #include "libudev.h"
 #include "libudev-private.h"
 #include "socket-util.h"
+#include "missing.h"
 
 /**
  * SECTION:libudev-monitor
@@ -95,7 +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;
@@ -105,6 +106,47 @@ static struct udev_monitor *udev_monitor_new(struct udev *udev)
         return udev_monitor;
 }
 
+/* we consider udev running when /dev is on devtmpfs */
+static bool udev_has_devtmpfs(struct udev *udev) {
+
+        union file_handle_union h = FILE_HANDLE_INIT;
+        _cleanup_fclose_ FILE *f = NULL;
+        char line[LINE_MAX], *e;
+        int mount_id;
+        int r;
+
+        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) {
+                int mid;
+
+                if (sscanf(line, "%i", &mid) != 1)
+                        continue;
+
+                if (mid != mount_id)
+                        continue;
+
+                e = strstr(line, " - ");
+                if (!e)
+                        continue;
+
+                /* accept any name that starts with the currently expected type */
+                if (startswith(e + 3, "devtmpfs"))
+                        return true;
+        }
+
+        return false;
+}
+
 struct udev_monitor *udev_monitor_new_from_netlink_fd(struct udev *udev, const char *name, int fd)
 {
         struct udev_monitor *udev_monitor;
@@ -115,9 +157,25 @@ struct udev_monitor *udev_monitor_new_from_netlink_fd(struct udev *udev, const c
 
         if (name == NULL)
                 group = UDEV_MONITOR_NONE;
-        else if (strcmp(name, "udev") == 0)
-                group = UDEV_MONITOR_UDEV;
-        else if (strcmp(name, "kernel") == 0)
+        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;
@@ -129,7 +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;
                 }
@@ -219,7 +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 */
@@ -288,7 +346,7 @@ _public_ int udev_monitor_filter_update(struct udev_monitor *udev_monitor)
                         bpf_stmt(ins, &i, BPF_RET|BPF_K, 0xffffffff);
 
                         if (i+1 >= ELEMENTSOF(ins))
-                                return -1;
+                                return -E2BIG;
                 }
 
                 /* nothing matched, drop packet */
@@ -299,11 +357,11 @@ _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));
-        return err;
+        return err < 0 ? -errno : 0;
 }
 
 int udev_monitor_allow_unicast_sender(struct udev_monitor *udev_monitor, struct udev_monitor *sender)
@@ -324,9 +382,6 @@ _public_ int udev_monitor_enable_receiving(struct udev_monitor *udev_monitor)
         int err = 0;
         const int on = 1;
 
-        if (udev_monitor->snl.nl.nl_family == 0)
-                return -EINVAL;
-
         udev_monitor_filter_update(udev_monitor);
 
         if (!udev_monitor->bound) {
@@ -349,12 +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");
-                return err;
+                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;
 }
 
@@ -371,7 +429,7 @@ _public_ int udev_monitor_enable_receiving(struct udev_monitor *udev_monitor)
 _public_ int udev_monitor_set_receive_buffer_size(struct udev_monitor *udev_monitor, int size)
 {
         if (udev_monitor == NULL)
-                return -1;
+                return -EINVAL;
         return setsockopt(udev_monitor->sock, SOL_SOCKET, SO_RCVBUFFORCE, &size, sizeof(size));
 }
 
@@ -381,7 +439,7 @@ int udev_monitor_disconnect(struct udev_monitor *udev_monitor)
 
         err = close(udev_monitor->sock);
         udev_monitor->sock = -1;
-        return err;
+        return err < 0 ? -errno : 0;
 }
 
 /**
@@ -408,7 +466,7 @@ _public_ struct udev_monitor *udev_monitor_ref(struct udev_monitor *udev_monitor
  * the bound socket will be closed, and the resources of the monitor
  * will be released.
  *
- * Returns: the passed udev monitor if it has still an active reference, or #NULL otherwise.
+ * Returns: #NULL
  **/
 _public_ struct udev_monitor *udev_monitor_unref(struct udev_monitor *udev_monitor)
 {
@@ -416,7 +474,7 @@ _public_ struct udev_monitor *udev_monitor_unref(struct udev_monitor *udev_monit
                 return NULL;
         udev_monitor->refcount--;
         if (udev_monitor->refcount > 0)
-                return udev_monitor;
+                return NULL;
         if (udev_monitor->sock >= 0)
                 close(udev_monitor->sock);
         udev_list_cleanup(&udev_monitor->filter_subsystem_list);
@@ -451,7 +509,7 @@ _public_ struct udev *udev_monitor_get_udev(struct udev_monitor *udev_monitor)
 _public_ int udev_monitor_get_fd(struct udev_monitor *udev_monitor)
 {
         if (udev_monitor == NULL)
-                return -1;
+                return -EINVAL;
         return udev_monitor->sock;
 }
 
@@ -467,7 +525,7 @@ static int passes_filter(struct udev_monitor *udev_monitor, struct udev_device *
                 const char *devtype;
                 const char *ddevtype;
 
-                if (strcmp(dsubsys, subsys) != 0)
+                if (!streq(dsubsys, subsys))
                         continue;
 
                 devtype = udev_list_entry_get_value(list_entry);
@@ -476,7 +534,7 @@ static int passes_filter(struct udev_monitor *udev_monitor, struct udev_device *
                 ddevtype = udev_device_get_devtype(udev_device);
                 if (ddevtype == NULL)
                         continue;
-                if (strcmp(ddevtype, devtype) == 0)
+                if (streq(ddevtype, devtype))
                         goto tag;
         }
         return 0;
@@ -521,104 +579,110 @@ _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;
-        struct udev_monitor_netlink_header *nlh;
 
 retry:
         if (udev_monitor == NULL)
                 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;
         smsg.msg_controllen = sizeof(cred_msg);
-
-        if (udev_monitor->snl.nl.nl_family != 0) {
-                smsg.msg_name = &snl;
-                smsg.msg_namelen = sizeof(snl);
-        }
+        smsg.msg_name = &snl;
+        smsg.msg_namelen = sizeof(snl);
 
         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;
         }
 
-        if (udev_monitor->snl.nl.nl_family != 0) {
-                if (snl.nl.nl_groups == 0) {
-                        /* 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");
-                                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",
-                                     snl.nl.nl_pid);
-                                return NULL;
-                        }
+        if (snl.nl.nl_groups == 0) {
+                /* 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) {
+                        log_debug("unicast netlink message ignored");
+                        return NULL;
+                }
+        } else if (snl.nl.nl_groups == UDEV_MONITOR_KERNEL) {
+                if (snl.nl.nl_pid > 0) {
+                        log_debug("multicast kernel netlink message from pid %d ignored",
+                             snl.nl.nl_pid);
+                        return NULL;
                 }
         }
 
         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;
         }
 
-        if (memcmp(buf, "libudev", 8) == 0) {
+        udev_device = udev_device_new(udev_monitor->udev);
+        if (udev_device == NULL)
+                return NULL;
+
+        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;
                 }
         }
 
-        udev_device = udev_device_new(udev_monitor->udev);
-        if (udev_device == NULL)
-                return NULL;
         udev_device_set_info_loaded(udev_device);
 
         while (bufpos < buflen) {
                 char *key;
                 size_t keylen;
 
-                key = &buf[bufpos];
+                key = &buf.raw[bufpos];
                 keylen = strlen(key);
                 if (keylen == 0)
                         break;
@@ -627,7 +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;
         }
@@ -664,15 +728,12 @@ int udev_monitor_send_device(struct udev_monitor *udev_monitor,
         struct udev_list_entry *list_entry;
         uint64_t tag_bloom_bits;
 
-        if (udev_monitor->snl.nl.nl_family == 0)
-                return -EINVAL;
-
         blen = udev_device_get_properties_monitor_buf(udev_device, &buf);
         if (blen < 32)
                 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);
@@ -699,7 +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;
         /*
@@ -714,7 +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;
 }