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authorLennart Poettering <lennart@poettering.net>2012-08-09 17:52:05 +0200
committerLennart Poettering <lennart@poettering.net>2012-08-09 17:52:05 +0200
commitcee5e9a7ca75f05d4a0f7759566e657587a500d5 (patch)
treef2876163081ce73cfc21b4fe046a24076fc92189 /src/journal
parentf7357f59c3d4de8080fa78f8aa5fa6dbf1afc8dc (diff)
journald: never read the same kernel msg twice, and generate message when we lose one
Diffstat (limited to 'src/journal')
-rw-r--r--src/journal/journald.c61
-rw-r--r--src/journal/journald.h2
2 files changed, 63 insertions, 0 deletions
diff --git a/src/journal/journald.c b/src/journal/journald.c
index 765c0e3428..7c89689e84 100644
--- a/src/journal/journald.c
+++ b/src/journal/journald.c
@@ -29,6 +29,7 @@
#include <sys/ioctl.h>
#include <linux/sockios.h>
#include <sys/statvfs.h>
+#include <sys/mman.h>
#include <systemd/sd-journal.h>
#include <systemd/sd-messages.h>
@@ -1846,6 +1847,22 @@ static void dev_kmsg_record(Server *s, char *p, size_t l) {
if (r < 0)
return;
+ if (s->kernel_seqnum) {
+ /* We already read this one? */
+ if (serial < *s->kernel_seqnum)
+ return;
+
+ /* Did we lose any? */
+ if (serial > *s->kernel_seqnum)
+ driver_message(s, SD_MESSAGE_JOURNAL_MISSED, "Missed %llu kernel messages", (unsigned long long) serial - *s->kernel_seqnum - 1);
+
+ /* Make sure we never read this one again. Note that
+ * we always store the next message serial we expect
+ * here, simply because this makes handling the first
+ * message with serial 0 easy. */
+ *s->kernel_seqnum = serial + 1;
+ }
+
l -= (e - p) + 1;
p = e + 1;
f = memchr(p, ';', l);
@@ -2607,6 +2624,41 @@ static int open_dev_kmsg(Server *s) {
return 0;
}
+static int open_kernel_seqnum(Server *s) {
+ int fd;
+ uint64_t *p;
+
+ assert(s);
+
+ /* We store the seqnum we last read in an mmaped file. That
+ * way we can just use it like a variable, but it is
+ * persistant and automatically flushed at reboot. */
+
+ fd = open("/run/systemd/journal/kernel-seqnum", O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW, 0644);
+ if (fd < 0) {
+ log_error("Failed to open /run/systemd/journal/kernel-seqnum, ignoring: %m");
+ return 0;
+ }
+
+ 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;
+}
+
static int open_signalfd(Server *s) {
sigset_t mask;
struct epoll_event ev;
@@ -2740,6 +2792,8 @@ static int server_init(Server *s) {
server_parse_config_file(s);
server_parse_proc_cmdline(s);
+ mkdir_p("/run/systemd/journal", 0755);
+
s->user_journals = hashmap_new(trivial_hash_func, trivial_compare_func);
if (!s->user_journals)
return log_oom();
@@ -2807,6 +2861,10 @@ static int server_init(Server *s) {
if (r < 0)
return r;
+ r = open_kernel_seqnum(s);
+ if (r < 0)
+ return r;
+
r = open_signalfd(s);
if (r < 0)
return r;
@@ -2861,6 +2919,9 @@ static void server_done(Server *s) {
if (s->rate_limit)
journal_rate_limit_free(s->rate_limit);
+ if (s->kernel_seqnum)
+ munmap(s->kernel_seqnum, sizeof(uint64_t));
+
free(s->buffer);
free(s->tty_path);
}
diff --git a/src/journal/journald.h b/src/journal/journald.h
index 7e23bfc2dc..d08a194780 100644
--- a/src/journal/journald.h
+++ b/src/journal/journald.h
@@ -94,6 +94,8 @@ typedef struct Server {
Storage storage;
bool dev_kmsg_readable;
+
+ uint64_t *kernel_seqnum;
} Server;
/* gperf lookup function */