In case of imminent crash or upon request (signal USR2),
dump the logging buffer to the libvirtd.log file for
post-mortem analysis
* daemon/libvirtd.c: create a sig_fatal() handler connected to
SIGFPE SIGSEGV SIGILL SIGABRT SIGBUS and SIGUSR2, just dumping
the log buffer to the libvirtd.log open file descriptor
Signed-off-by: Daniel Veillard <veill...@redhat.com>
---
daemon/libvirtd.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 51 insertions(+), 0 deletions(-)
diff --git a/daemon/libvirtd.c b/daemon/libvirtd.c
index 42e8585..3338336 100644
--- a/daemon/libvirtd.c
+++ b/daemon/libvirtd.c
@@ -248,6 +248,45 @@ static void sig_handler(int sig, siginfo_t * siginfo,
errno = origerrno;
}
+static int sig_fatal_dump(void *data ATTRIBUTE_UNUSED,
+ const char *buf, int len) {
+ int r;
+
+ r = safewrite(logFD, buf, len);
+ return(r);
+}
+
+static void sig_fatal(int sig, siginfo_t * siginfo ATTRIBUTE_UNUSED,
+ void* context ATTRIBUTE_UNUSED) {
+ struct sigaction sig_action;
+ int origerrno;
+ int r;
+ char buf[100];
+
+ origerrno = errno;
+ snprintf(buf, sizeof(buf) - 1,
+ "Caught signal %d, dumping internal log buffer:\n", sig);
+ buf[sizeof(buf) - 1] = 0;
+ r = safewrite(logFD, buf, strlen(buf));
+ snprintf(buf, sizeof(buf) - 1, "\n\n ====== start of log =====\n\n");
+ r = safewrite(logFD, buf, strlen(buf));
+ virLogDump(NULL, sig_fatal_dump);
+ snprintf(buf, sizeof(buf) - 1, "\n\n ====== end of log =====\n\n");
+ r = safewrite(logFD, buf, strlen(buf));
+ fsync(logFD);
+
+ /*
+ * If the signal is fatal, avoid looping over this handler
+ * by desactivating it
+ */
+ if (sig != SIGUSR2) {
+ sig_action.sa_flags = SA_SIGINFO;
+ sig_action.sa_handler = SIG_IGN;
+ sigaction(sig, &sig_action, NULL);
+ }
+ errno = origerrno;
+}
+
static void qemudDispatchClientEvent(int watch, int fd, int events, void *opaque);
static void qemudDispatchServerEvent(int watch, int fd, int events, void *opaque);
static int qemudStartWorker(struct qemud_server *server, struct qemud_worker *worker);
@@ -3099,6 +3138,18 @@ daemonSetupSignals(struct qemud_server *server)
sigaction(SIGQUIT, &sig_action, NULL);
sigaction(SIGTERM, &sig_action, NULL);
+ /*
+ * catch fatal errors to dump a log, also hook to USR2 for dynamic
+ * debugging purposes or testing
+ */
+ sig_action.sa_sigaction = sig_fatal;
+ sigaction(SIGFPE, &sig_action, NULL);
+ sigaction(SIGSEGV, &sig_action, NULL);
+ sigaction(SIGILL, &sig_action, NULL);
+ sigaction(SIGABRT, &sig_action, NULL);
+ sigaction(SIGBUS, &sig_action, NULL);
+ sigaction(SIGUSR2, &sig_action, NULL);
+
sig_action.sa_handler = SIG_IGN;
sigaction(SIGPIPE, &sig_action, NULL);
--
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