journald: downgrade warning message when /dev/kmsg does not exist

[elogind.git] / src / journal / journald-kmsg.c

diff --git a/src/journal/journald-kmsg.c b/src/journal/journald-kmsg.c
index b8198760d6938364e910cddb74a6d5522fd34001..1730a23a97bc179d4f3947c468f9458bddebfeb1 100644 (file)
--- a/src/journal/journald-kmsg.c
+++ b/src/journal/journald-kmsg.c
@@ -88,7 +88,7 @@ void server_forward_kmsg(
         IOVEC_SET_STRING(iovec[n++], "\n");
 
         if (writev(s->dev_kmsg_fd, iovec, n) < 0)
-                log_debug("Failed to write to /dev/kmsg for logging: %s", strerror(errno));
+                log_debug("Failed to write to /dev/kmsg for logging: %m");
 
         free(ident_buf);
 }
@@ -151,7 +151,8 @@ static void dev_kmsg_record(Server *s, char *p, size_t l) {
 
                 /* Did we lose any? */
                 if (serial > *s->kernel_seqnum)
-                        server_driver_message(s, SD_MESSAGE_JOURNAL_MISSED, "Missed %llu kernel messages", (unsigned long long) serial - *s->kernel_seqnum - 1);
+                        server_driver_message(s, SD_MESSAGE_JOURNAL_MISSED, "Missed %"PRIu64" kernel messages",
+                                              serial - *s->kernel_seqnum - 1);
 
                 /* Make sure we never read this one again. Note that
                  * we always store the next message serial we expect
@@ -250,10 +251,12 @@ static void dev_kmsg_record(Server *s, char *p, size_t l) {
                                         break;
 
                                 g = udev_list_entry_get_name(ll);
-                                b = strappend("_UDEV_DEVLINK=", g);
                                 if (g) {
-                                        IOVEC_SET_STRING(iovec[n++], b);
-                                        z++;
+                                        b = strappend("_UDEV_DEVLINK=", g);
+                                        if (b) {
+                                                IOVEC_SET_STRING(iovec[n++], b);
+                                                z++;
+                                        }
                                 }
 
                                 j++;
@@ -301,7 +304,7 @@ static void dev_kmsg_record(Server *s, char *p, size_t l) {
         if (message)
                 IOVEC_SET_STRING(iovec[n++], message);
 
-        server_dispatch_message(s, iovec, n, ELEMENTSOF(iovec), NULL, NULL, NULL, 0, NULL, priority);
+        server_dispatch_message(s, iovec, n, ELEMENTSOF(iovec), NULL, NULL, NULL, 0, NULL, priority, 0);
 
 finish:
         for (j = 0; j < z; j++)
@@ -317,7 +320,7 @@ finish:
         free(pid);
 }
 
-int server_read_dev_kmsg(Server *s) {
+static int server_read_dev_kmsg(Server *s) {
         char buffer[8192+1]; /* the kernel-side limit per record is 8K currently */
         ssize_t l;
 
@@ -332,7 +335,7 @@ int server_read_dev_kmsg(Server *s) {
                  * return EINVAL when we try. So handle this cleanly,
                  * but don' try to ever read from it again. */
                 if (errno == EINVAL) {
-                        epoll_ctl(s->epoll_fd, EPOLL_CTL_DEL, s->dev_kmsg_fd, NULL);
+                        s->dev_kmsg_event_source = sd_event_source_unref(s->dev_kmsg_event_source);
                         return 0;
                 }
 
@@ -372,28 +375,49 @@ int server_flush_dev_kmsg(Server *s) {
         return 0;
 }
 
+static int dispatch_dev_kmsg(sd_event_source *es, int fd, uint32_t revents, void *userdata) {
+        Server *s = userdata;
+
+        assert(es);
+        assert(fd == s->dev_kmsg_fd);
+        assert(s);
+
+        if (revents & EPOLLERR)
+                log_warning("/dev/kmsg buffer overrun, some messages lost.");
+
+        if (!(revents & EPOLLIN))
+                log_error("Got invalid event from epoll for /dev/kmsg: %"PRIx32, revents);
+
+        return server_read_dev_kmsg(s);
+}
+
 int server_open_dev_kmsg(Server *s) {
-        struct epoll_event ev;
+        int r;
 
         assert(s);
 
         s->dev_kmsg_fd = open("/dev/kmsg", O_RDWR|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
         if (s->dev_kmsg_fd < 0) {
-                log_warning("Failed to open /dev/kmsg, ignoring: %m");
+                log_full(errno == ENOENT ? LOG_DEBUG : LOG_WARNING,
+                         "Failed to open /dev/kmsg, ignoring: %m");
                 return 0;
         }
 
-        zero(ev);
-        ev.events = EPOLLIN;
-        ev.data.fd = s->dev_kmsg_fd;
-        if (epoll_ctl(s->epoll_fd, EPOLL_CTL_ADD, s->dev_kmsg_fd, &ev) < 0) {
+        r = sd_event_add_io(s->event, s->dev_kmsg_fd, EPOLLIN, dispatch_dev_kmsg, s, &s->dev_kmsg_event_source);
+        if (r < 0) {
 
                 /* This will fail with EPERM on older kernels where
                  * /dev/kmsg is not readable. */
-                if (errno == EPERM)
+                if (r == -EPERM)
                         return 0;
 
-                log_error("Failed to add /dev/kmsg fd to epoll object: %m");
+                log_error("Failed to add /dev/kmsg fd to event loop: %s", strerror(-r));
+                return -errno;
+        }
+
+        r = sd_event_source_set_priority(s->dev_kmsg_event_source, SD_EVENT_PRIORITY_IMPORTANT+10);
+        if (r < 0) {
+                log_error("Failed to adjust priority of kmsg event source: %s", strerror(-r));
                 return -errno;
         }