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coredump: avoid coredump loops, divert coredump if journald itself is crashing

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This commit is contained in:
Lennart Poettering 2012-02-02 01:22:49 +01:00
parent 5d6b158473
commit 803a3464ce
2 changed files with 84 additions and 13 deletions
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2
TODO
View File

@ -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

95
src/journal/coredump.c
View File

@ -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);