X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Flibudev%2Flibudev-monitor.c;h=bdb551604764a4936616baa37f18587f51c26fad;hp=a6dba893763a0f55aa0de3321d0abac62fd09bc0;hb=ff49bc3212cb07d850dcfd59940539773a0be26f;hpb=f6613dd959a1ab49bf061555ada77903397569ad

diff --git a/src/libudev/libudev-monitor.c b/src/libudev/libudev-monitor.c
index a6dba8937..bdb551604 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 +106,50 @@ 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 = {
+                .handle.handle_bytes = MAX_HANDLE_SZ
+        };
+
+        _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("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 +160,25 @@ 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;
@@ -129,7 +190,7 @@ 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("error getting socket: %m");
                         free(udev_monitor);
                         return NULL;
                 }
@@ -219,7 +280,7 @@ _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 */
@@ -299,7 +360,7 @@ _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));
@@ -346,12 +407,15 @@ _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("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("setting SO_PASSCRED failed: %m");
+
         return 0;
 }
 
@@ -527,7 +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;
@@ -538,12 +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");
+                log_debug("invalid message length");
                 return NULL;
         }
 
@@ -551,12 +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;
                 }
@@ -564,13 +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;
         }
 
@@ -584,7 +648,7 @@ retry:
                 /* 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",
+                        log_debug("unrecognized message signature (%x != %x)",
                                  nlh->magic, htonl(UDEV_MONITOR_MAGIC));
                         udev_device_unref(udev_device);
                         return NULL;
@@ -602,14 +666,14 @@ retry:
                 /* kernel message with header */
                 bufpos = strlen(buf) + 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");
+                        log_debug("unrecognized message header");
                         udev_device_unref(udev_device);
                         return NULL;
                 }
@@ -630,7 +694,7 @@ 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;
         }
@@ -672,7 +736,7 @@ 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);
@@ -699,7 +763,7 @@ 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 +778,7 @@ 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;
 }