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authorLennart Poettering <lennart@poettering.net>2015-11-11 12:59:09 +0100
committerLennart Poettering <lennart@poettering.net>2015-11-11 13:39:18 +0100
commit94b6551662e0db8eb09768ed70f77759f322b4c6 (patch)
tree6c49b11d5b62d68094dabc71b5a0634da6312ffc /src
parent404f08d341c6fcd5f28664902adefd069f2082cd (diff)
journalctl: add new --sync switch for syncing the journal to disk
With this new "--sync" switch we add a synchronous way to sync everything queued to disk, and return only after that's complete. This command gives the guarantee that anything queued before has hit the disk before the command returns. While we are at it, also improve the man pages and help text for journalctl a bit.
Diffstat (limited to 'src')
-rw-r--r--src/journal/journalctl.c106
-rw-r--r--src/journal/journald-server.c35
-rw-r--r--src/journal/journald-server.h1
3 files changed, 131 insertions, 11 deletions
diff --git a/src/journal/journalctl.c b/src/journal/journalctl.c
index 277adba904..071349666c 100644
--- a/src/journal/journalctl.c
+++ b/src/journal/journalctl.c
@@ -135,6 +135,7 @@ static enum {
ACTION_FLUSH,
ACTION_ROTATE,
ACTION_VACUUM,
+ ACTION_SYNC,
} arg_action = ACTION_SHOW;
typedef struct BootId {
@@ -201,7 +202,7 @@ static void help(void) {
printf("%s [OPTIONS...] [MATCHES...]\n\n"
"Query the journal.\n\n"
- "Flags:\n"
+ "Options:\n"
" --system Show the system journal\n"
" --user Show the user journal for the current user\n"
" -M --machine=CONTAINER Operate on local container\n"
@@ -234,7 +235,7 @@ static void help(void) {
" -m --merge Show entries from all available journals\n"
" -D --directory=PATH Show journal files from directory\n"
" --file=PATH Show journal file\n"
- " --root=ROOT Operate on catalog files underneath the root ROOT\n"
+ " --root=ROOT Operate on catalog files below a root directory\n"
#ifdef HAVE_GCRYPT
" --interval=TIME Time interval for changing the FSS sealing key\n"
" --verify-key=KEY Specify FSS verification key\n"
@@ -244,20 +245,21 @@ static void help(void) {
" -h --help Show this help text\n"
" --version Show package version\n"
" -F --field=FIELD List all values that a specified field takes\n"
- " --new-id128 Generate a new 128-bit ID\n"
" --disk-usage Show total disk usage of all journal files\n"
" --vacuum-size=BYTES Reduce disk usage below specified size\n"
" --vacuum-files=INT Leave only the specified number of journal files\n"
" --vacuum-time=TIME Remove journal files older than specified time\n"
+ " --verify Verify journal file consistency\n"
+ " --sync Synchronize unwritten journal messages to disk\n"
" --flush Flush all journal data from /run into /var\n"
" --rotate Request immediate rotation of the journal files\n"
" --header Show journal header information\n"
" --list-catalog Show all message IDs in the catalog\n"
" --dump-catalog Show entries in the message catalog\n"
" --update-catalog Update the message catalog database\n"
+ " --new-id128 Generate a new 128-bit ID\n"
#ifdef HAVE_GCRYPT
" --setup-keys Generate a new FSS key pair\n"
- " --verify Verify journal file consistency\n"
#endif
, program_invocation_short_name);
}
@@ -289,6 +291,7 @@ static int parse_argv(int argc, char *argv[]) {
ARG_UPDATE_CATALOG,
ARG_FORCE,
ARG_UTC,
+ ARG_SYNC,
ARG_FLUSH,
ARG_ROTATE,
ARG_VACUUM_SIZE,
@@ -345,6 +348,7 @@ static int parse_argv(int argc, char *argv[]) {
{ "machine", required_argument, NULL, 'M' },
{ "utc", no_argument, NULL, ARG_UTC },
{ "flush", no_argument, NULL, ARG_FLUSH },
+ { "sync", no_argument, NULL, ARG_SYNC },
{ "rotate", no_argument, NULL, ARG_ROTATE },
{ "vacuum-size", required_argument, NULL, ARG_VACUUM_SIZE },
{ "vacuum-files", required_argument, NULL, ARG_VACUUM_FILES },
@@ -729,6 +733,10 @@ static int parse_argv(int argc, char *argv[]) {
arg_action = ACTION_ROTATE;
break;
+ case ARG_SYNC:
+ arg_action = ACTION_SYNC;
+ break;
+
case '?':
return -EINVAL;
@@ -1782,10 +1790,8 @@ static int flush_to_var(void) {
&error,
NULL,
"ssi", "systemd-journald.service", "main", SIGUSR1);
- if (r < 0) {
- log_error("Failed to kill journal service: %s", bus_error_message(&error, r));
- return r;
- }
+ if (r < 0)
+ return log_error_errno(r, "Failed to kill journal service: %s", bus_error_message(&error, r));
mkdir_p("/run/systemd/journal", 0755);
@@ -1840,6 +1846,85 @@ static int rotate(void) {
return 0;
}
+static int sync_journal(void) {
+ _cleanup_bus_flush_close_unref_ sd_bus *bus = NULL;
+ _cleanup_close_ int watch_fd = -1;
+ usec_t start;
+ int r;
+
+ start = now(CLOCK_REALTIME);
+
+ /* Let's watch /run/systemd/sync until it's mtime is above
+ * the time we started the sync. Let's enqueue SIGRTMIN+1 to
+ * start the sync. */
+
+ for (;;) {
+ struct stat st;
+
+ /* See if a sync happened by now. */
+ if (stat("/run/systemd/journal/synced", &st) < 0) {
+ if (errno != ENOENT)
+ return log_error_errno(errno, "Failed to stat /run/systemd/journal/synced: %m");
+ } else {
+ if (timespec_load(&st.st_mtim) >= start)
+ return 0;
+ }
+
+ /* Let's ask for a sync, but only once. */
+ if (!bus) {
+ _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
+
+ r = bus_connect_system_systemd(&bus);
+ if (r < 0)
+ return log_error_errno(r, "Failed to get D-Bus connection: %m");
+
+ r = sd_bus_call_method(
+ bus,
+ "org.freedesktop.systemd1",
+ "/org/freedesktop/systemd1",
+ "org.freedesktop.systemd1.Manager",
+ "KillUnit",
+ &error,
+ NULL,
+ "ssi", "systemd-journald.service", "main", SIGRTMIN+1);
+ if (r < 0)
+ return log_error_errno(r, "Failed to kill journal service: %s", bus_error_message(&error, r));
+
+ continue;
+ }
+
+ /* Let's install the inotify watch, if we didn't do that yet. */
+ if (watch_fd < 0) {
+
+ mkdir_p("/run/systemd/journal", 0755);
+
+ watch_fd = inotify_init1(IN_NONBLOCK|IN_CLOEXEC);
+ if (watch_fd < 0)
+ return log_error_errno(errno, "Failed to create inotify watch: %m");
+
+ r = inotify_add_watch(watch_fd, "/run/systemd/journal", IN_CREATE|IN_ATTRIB|IN_DONT_FOLLOW|IN_ONLYDIR);
+ if (r < 0)
+ return log_error_errno(errno, "Failed to watch journal directory: %m");
+
+ /* Recheck the flag file immediately, so that we don't miss any event since the last check. */
+ continue;
+ }
+
+ /* OK, all preparatory steps done, let's wait until
+ * inotify reports an event. */
+
+ r = fd_wait_for_event(watch_fd, POLLIN, USEC_INFINITY);
+ if (r < 0)
+ return log_error_errno(r, "Failed to wait for event: %m");
+
+ r = flush_fd(watch_fd);
+ if (r < 0)
+ return log_error_errno(r, "Failed to flush inotify events: %m");
+ }
+
+ return 0;
+}
+
int main(int argc, char *argv[]) {
int r;
_cleanup_journal_close_ sd_journal *j = NULL;
@@ -1875,6 +1960,11 @@ int main(int argc, char *argv[]) {
goto finish;
}
+ if (arg_action == ACTION_SYNC) {
+ r = sync_journal();
+ goto finish;
+ }
+
if (arg_action == ACTION_ROTATE) {
r = rotate();
goto finish;
diff --git a/src/journal/journald-server.c b/src/journal/journald-server.c
index a6e5e4a20f..f0a3c82d98 100644
--- a/src/journal/journald-server.c
+++ b/src/journal/journald-server.c
@@ -1243,7 +1243,7 @@ static int dispatch_sigusr1(sd_event_source *es, const struct signalfd_siginfo *
assert(s);
- log_info("Received request to flush runtime journal from PID %"PRIu32, si->ssi_pid);
+ log_info("Received request to flush runtime journal from PID " PID_FMT, si->ssi_pid);
server_flush_to_var(s);
server_sync(s);
@@ -1259,7 +1259,7 @@ static int dispatch_sigusr2(sd_event_source *es, const struct signalfd_siginfo *
assert(s);
- log_info("Received request to rotate journal from PID %"PRIu32, si->ssi_pid);
+ log_info("Received request to rotate journal from PID " PID_FMT, si->ssi_pid);
server_rotate(s);
server_vacuum(s, true, true);
@@ -1277,12 +1277,27 @@ static int dispatch_sigterm(sd_event_source *es, const struct signalfd_siginfo *
return 0;
}
+static int dispatch_sigrtmin1(sd_event_source *es, const struct signalfd_siginfo *si, void *userdata) {
+ Server *s = userdata;
+
+ assert(s);
+
+ log_debug("Received request to sync from PID " PID_FMT, si->ssi_pid);
+
+ server_sync(s);
+
+ /* Let clients know when the most recent sync happened. */
+ (void) touch("/run/systemd/journal/synced");
+
+ return 0;
+}
+
static int setup_signals(Server *s) {
int r;
assert(s);
- assert(sigprocmask_many(SIG_SETMASK, NULL, SIGINT, SIGTERM, SIGUSR1, SIGUSR2, -1) >= 0);
+ assert(sigprocmask_many(SIG_SETMASK, NULL, SIGINT, SIGTERM, SIGUSR1, SIGUSR2, SIGRTMIN+1, -1) >= 0);
r = sd_event_add_signal(s->event, &s->sigusr1_event_source, SIGUSR1, dispatch_sigusr1, s);
if (r < 0)
@@ -1312,6 +1327,19 @@ static int setup_signals(Server *s) {
if (r < 0)
return r;
+ /* SIGRTMIN+1 causes an immediate sync. We process this very
+ * late, so that everything else queued at this point is
+ * really written to disk. Clients can watch
+ * /run/systemd/journal/synced with inotify until its mtime
+ * changes to see when a sync happened. */
+ r = sd_event_add_signal(s->event, &s->sigrtmin1_event_source, SIGRTMIN+1, dispatch_sigrtmin1, s);
+ if (r < 0)
+ return r;
+
+ r = sd_event_source_set_priority(s->sigrtmin1_event_source, SD_EVENT_PRIORITY_NORMAL+15);
+ if (r < 0)
+ return r;
+
return 0;
}
@@ -1869,6 +1897,7 @@ void server_done(Server *s) {
sd_event_source_unref(s->sigusr2_event_source);
sd_event_source_unref(s->sigterm_event_source);
sd_event_source_unref(s->sigint_event_source);
+ sd_event_source_unref(s->sigrtmin1_event_source);
sd_event_source_unref(s->hostname_event_source);
sd_event_source_unref(s->notify_event_source);
sd_event_source_unref(s->watchdog_event_source);
diff --git a/src/journal/journald-server.h b/src/journal/journald-server.h
index 03a61bd2ed..dcc21bb7c3 100644
--- a/src/journal/journald-server.h
+++ b/src/journal/journald-server.h
@@ -72,6 +72,7 @@ struct Server {
sd_event_source *sigusr2_event_source;
sd_event_source *sigterm_event_source;
sd_event_source *sigint_event_source;
+ sd_event_source *sigrtmin1_event_source;
sd_event_source *hostname_event_source;
sd_event_source *notify_event_source;
sd_event_source *watchdog_event_source;