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authorLennart Poettering <lennart@poettering.net>2012-02-02 01:22:49 +0100
committerLennart Poettering <lennart@poettering.net>2012-02-02 01:22:49 +0100
commit803a3464ce5b8383101467b1277e72713dd75e6b (patch)
tree934ee1a16575cc5c720c473aa9b1dfe4b71013cd
parent5d6b158473100a7a85e790f8ead0b826baa13b5e (diff)
coredump: avoid coredump loops, divert coredump if journald itself is crashing
-rw-r--r--TODO2
-rw-r--r--src/journal/coredump.c95
2 files changed, 84 insertions, 13 deletions
diff --git a/TODO b/TODO
index baf4840cdb..a7081d868f 100644
--- a/TODO
+++ b/TODO
@@ -27,8 +27,6 @@ Features:
* Fedora: disable journald's /proc/kmsg reading on Fedora for now
-* avoid that we choke on journal coredump loops (i.e. where the journal crashes and causes a coredump to be fed back to it)
-
* write RPM spec macros for presets
* write man pages for systemd-cgtop, systemd-cat
diff --git a/src/journal/coredump.c b/src/journal/coredump.c
index 6b8809972d..7dea66e6fd 100644
--- a/src/journal/coredump.c
+++ b/src/journal/coredump.c
@@ -21,12 +21,15 @@
#include <errno.h>
#include <unistd.h>
+#include <stdio.h>
+#include <sys/prctl.h>
#include <systemd/sd-journal.h>
#include <systemd/sd-login.h>
#include "log.h"
#include "util.h"
+#include "special.h"
#define COREDUMP_MAX (24*1024*1024)
@@ -40,6 +43,56 @@ enum {
_ARG_MAX
};
+static int divert_coredump(void) {
+ FILE *f;
+ int r;
+
+ log_info("Detected coredump of the journal daemon itself, diverting coredump to /var/lib/systemd/coredump/.");
+
+ mkdir_p("/var/lib/systemd/coredump", 0755);
+
+ f = fopen("/var/lib/systemd/coredump/core.systemd-journald", "we");
+ if (!f) {
+ log_error("Failed to create coredump file: %m");
+ return -errno;
+ }
+
+ for (;;) {
+ uint8_t buffer[4096];
+ size_t l, q;
+
+ l = fread(buffer, 1, sizeof(buffer), stdin);
+ if (l <= 0) {
+ if (ferror(f)) {
+ log_error("Failed to read coredump: %m");
+ r = -errno;
+ goto finish;
+ }
+
+ r = 0;
+ break;
+ }
+
+ q = fwrite(buffer, 1, l, f);
+ if (q != l) {
+ log_error("Failed to write coredump: %m");
+ r = -errno;
+ goto finish;
+ }
+ }
+
+ fflush(f);
+
+ if (ferror(f)) {
+ log_error("Failed to write coredump: %m");
+ r = -errno;
+ }
+
+finish:
+ fclose(f);
+ return r;
+}
+
int main(int argc, char* argv[]) {
int r, j = 0;
char *p = NULL;
@@ -52,11 +105,12 @@ int main(int argc, char* argv[]) {
*core_timestamp = NULL, *core_comm = NULL, *core_exe = NULL, *core_unit = NULL,
*core_session = NULL, *core_message = NULL, *core_cmdline = NULL, *t;
- log_set_target(LOG_TARGET_JOURNAL_OR_KMSG);
- log_parse_environment();
- log_open();
+ prctl(PR_SET_DUMPABLE, 0);
if (argc != _ARG_MAX) {
+ log_set_target(LOG_TARGET_JOURNAL_OR_KMSG);
+ log_open();
+
log_error("Invalid number of arguments passed from kernel.");
r = -EINVAL;
goto finish;
@@ -64,10 +118,37 @@ int main(int argc, char* argv[]) {
r = parse_pid(argv[ARG_PID], &pid);
if (r < 0) {
+ log_set_target(LOG_TARGET_JOURNAL_OR_KMSG);
+ log_open();
+
log_error("Failed to parse PID.");
goto finish;
}
+ if (sd_pid_get_unit(pid, &t) >= 0) {
+
+ if (streq(t, SPECIAL_JOURNALD_SERVICE)) {
+ /* Make sure we don't make use of the journal,
+ * if it's the journal which is crashing */
+ log_set_target(LOG_TARGET_KMSG);
+ log_open();
+
+ r = divert_coredump();
+ goto finish;
+ }
+
+ core_unit = strappend("COREDUMP_UNIT=", t);
+ free(t);
+
+ if (core_unit)
+ IOVEC_SET_STRING(iovec[j++], core_unit);
+ }
+
+ /* OK, now we know it's not the journal, hence make use of
+ * it */
+ log_set_target(LOG_TARGET_JOURNAL_OR_KMSG);
+ log_open();
+
r = parse_uid(argv[ARG_UID], &uid);
if (r < 0) {
log_error("Failed to parse UID.");
@@ -108,14 +189,6 @@ int main(int argc, char* argv[]) {
IOVEC_SET_STRING(iovec[j++], core_session);
}
- if (sd_pid_get_unit(pid, &t) >= 0) {
- core_unit = strappend("COREDUMP_UNIT=", t);
- free(t);
-
- if (core_unit)
- IOVEC_SET_STRING(iovec[j++], core_unit);
- }
-
if (get_process_exe(pid, &t) >= 0) {
core_exe = strappend("COREDUMP_EXE=", t);
free(t);