journald: Fix off-by-one error in "Missed X kernel messages" warning

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

diff --git a/src/journal/journald-kmsg.c b/src/journal/journald-kmsg.c
index af49d8578a8ec3ba0e6390ff063130d7d83908a2..fb8ea08e31b56dd25b30ac0d684da22299e70dd7 100644 (file)
--- a/src/journal/journald-kmsg.c
+++ b/src/journal/journald-kmsg.c
@@ -25,7 +25,7 @@
 #include <sys/mman.h>
 #include <sys/socket.h>
 
-#include <systemd/sd-messages.h>
+#include "systemd/sd-messages.h"
 #include <libudev.h>
 
 #include "journald-server.h"
@@ -71,7 +71,7 @@ void server_forward_kmsg(
                         identifier = ident_buf;
                 }
 
-                snprintf(header_pid, sizeof(header_pid), "[%lu]: ", (unsigned long) ucred->pid);
+                snprintf(header_pid, sizeof(header_pid), "["PID_FMT"]: ", ucred->pid);
                 char_array_0(header_pid);
 
                 if (identifier)
@@ -152,7 +152,7 @@ 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 %"PRIu64" kernel messages",
-                                              serial - *s->kernel_seqnum - 1);
+                                              serial - *s->kernel_seqnum);
 
                 /* Make sure we never read this one again. Note that
                  * we always store the next message serial we expect
@@ -274,6 +274,9 @@ static void dev_kmsg_record(Server *s, char *p, size_t l) {
         if (asprintf(&syslog_priority, "PRIORITY=%i", priority & LOG_PRIMASK) >= 0)
                 IOVEC_SET_STRING(iovec[n++], syslog_priority);
 
+        if (asprintf(&syslog_facility, "SYSLOG_FACILITY=%i", LOG_FAC(priority)) >= 0)
+                IOVEC_SET_STRING(iovec[n++], syslog_facility);
+
         if ((priority & LOG_FACMASK) == LOG_KERN)
                 IOVEC_SET_STRING(iovec[n++], "SYSLOG_IDENTIFIER=kernel");
         else {
@@ -295,9 +298,6 @@ static void dev_kmsg_record(Server *s, char *p, size_t l) {
                         if (syslog_pid)
                                 IOVEC_SET_STRING(iovec[n++], syslog_pid);
                 }
-
-                if (asprintf(&syslog_facility, "SYSLOG_FACILITY=%i", LOG_FAC(priority)) >= 0)
-                        IOVEC_SET_STRING(iovec[n++], syslog_facility);
         }
 
         message = cunescape_length_with_prefix(p, pl, "MESSAGE=");
@@ -320,7 +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;
 
@@ -335,7 +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;
                 }
 
@@ -375,38 +375,67 @@ 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_event_source, s->dev_kmsg_fd, EPOLLIN, dispatch_dev_kmsg, s);
+        if (r < 0) {
 
                 /* This will fail with EPERM on older kernels where
                  * /dev/kmsg is not readable. */
-                if (errno == EPERM)
-                        return 0;
+                if (r == -EPERM) {
+                        r = 0;
+                        goto fail;
+                }
 
-                log_error("Failed to add /dev/kmsg fd to epoll object: %m");
-                return -errno;
+                log_error("Failed to add /dev/kmsg fd to event loop: %s", strerror(-r));
+                goto fail;
+        }
+
+        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));
+                goto fail;
         }
 
         s->dev_kmsg_readable = true;
 
         return 0;
+
+fail:
+        s->dev_kmsg_event_source = sd_event_source_unref(s->dev_kmsg_event_source);
+        s->dev_kmsg_fd = safe_close(s->dev_kmsg_fd);
+
+        return r;
 }
 
 int server_open_kernel_seqnum(Server *s) {
-        int fd;
+        _cleanup_close_ int fd;
         uint64_t *p;
 
         assert(s);
@@ -423,18 +452,15 @@ int server_open_kernel_seqnum(Server *s) {
 
         if (posix_fallocate(fd, 0, sizeof(uint64_t)) < 0) {
                 log_error("Failed to allocate sequential number file, ignoring: %m");
-                close_nointr_nofail(fd);
                 return 0;
         }
 
         p = mmap(NULL, sizeof(uint64_t), PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
         if (p == MAP_FAILED) {
                 log_error("Failed to map sequential number file, ignoring: %m");
-                close_nointr_nofail(fd);
                 return 0;
         }
 
-        close_nointr_nofail(fd);
         s->kernel_seqnum = p;
 
         return 0;