[Nagios-devel] [PATCH] core: Avoid lock file removal race condition

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[Nagios-devel] [PATCH] core: Avoid lock file removal race condition

Postby Guest » Tue Apr 09, 2013 1:28 pm

--047d7b33dd70bb676904d9ee5b98
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This patch avoids a race condition in removal of lock files. The race
condition happens when:

1. we receive a SIGHUP, breaking us out of the event execution loop, and
2. receive a SIGTERM - or any other "shutdown" signal - AFTER checking for
the sigshutdown state but BEFORE the do-while loop terminates. I.e, during
execution of cleanup() or close_debug_log() towards the end of the loop.

Signed-off-by: Anton Lofgren
---
base/nagios.c | 15 +++++++++++----
base/utils.c | 1 -
2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/base/nagios.c b/base/nagios.c
index 6b834b2..806d355 100644
--- a/base/nagios.c
+++ b/base/nagios.c
@@ -539,6 +539,11 @@ int main(int argc, char **argv) {

/* keep monitoring things until we get a shutdown command */
do {
+ if (daemon_mode == TRUE && sigrestart == TRUE) {
+ /* if we've restarted in daemon mode, we don't want to
leak the
+ * lock file */
+ my_free(lock_file);
+ }

/* reset program variables */
reset_variables();
@@ -827,10 +832,6 @@ int main(int argc, char **argv) {
iobroker_destroy(nagios_iobs, IOBROKER_CLOSE_SOCKETS);
nagios_iobs = NULL;

- /* make sure lock file has been removed - it may not have
been if we received a shutdown command */
- if(daemon_mode == TRUE)
- unlink(lock_file);
-
/* log a shutdown message */
logit(NSLOG_PROCESS_INFO, TRUE, "Successfully shutdown...
(PID=%d)\n", (int)getpid());
}
@@ -844,6 +845,12 @@ int main(int argc, char **argv) {
}
while(sigrestart == TRUE && sigshutdown == FALSE);

+ /* make sure lock file has been removed - it may not have been if
we received a shutdown command */
+ if(daemon_mode == TRUE) {
+ unlink(lock_file);
+ my_free(lock_file);
+ }
+
/* free misc memory */
my_free(config_file);
}
diff --git a/base/utils.c b/base/utils.c
index af95663..1ff1e7b 100644
--- a/base/utils.c
+++ b/base/utils.c
@@ -3157,7 +3157,6 @@ void free_memory(nagios_macros *mac) {
my_free(temp_path);
my_free(check_result_path);
my_free(command_file);
- my_free(lock_file);
my_free(log_archive_path);

return;
--
1.8.2

--047d7b33dd70bb676904d9ee5b98
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This patch avoids a=A0 race condition in removal of lock f=
iles. The race
condition happens when:

1. we receive a SIGHUP, br=
eaking us out of the event execution loop, and
2. receive a SIGTERM - or=
any other "shutdown" signal - AFTER checking for

the sigshutdown state but BEFORE the do-while loop terminates. I.e, during<=
br>execution of cleanup() or close_debug_log() towards the end of the loop.=


Signed-off-by: Anton Lofgren <">alofgren@op5.com>

---
=A0base/nagios.c | 15 +++++++++++----
=A0base/utils.c=A0 |=A0 1 -=

=A02 files changed, 11 insertions(+), 5 deletions(-)

diff --git =
a/base/nagios.c b/base/nagios.c
index 6b834b2..806d355 100644
--- a/b=
ase/nagios.c

+++ b/base/nagios.c
@@ -539,6 +539,11 @@ int main(int argc, char **argv)=
{
=A0
=A0=A0=A0=A0 =A0=A0=A0 /* keep monitoring things until we get =
a shutdown command */
=A0=A0=A0=A0 =A0=A0=A0 do {
+=A0=A0=A0 =A0=A0=
=A0 =A0=A0=A0 if (daemon_mode =3D=3D TRUE && sigrestart =3D=3D TRUE=
) {

+=A0=A0=A0 =A0=A0=A0 =A0=A0=A0 =A0=A0=A0 /* if we've restarted in daemo=
n mode, we don't want to leak the
+=A0=A0=A0 =A0=A0=A0 =A0=A0=A0 =A0=
=A0=A0 =A0* lock file */
+=A0=A0=A0 =A0=A0=A0 =A0=A0=A0 =A0=A0=A0 my_fre=
e(lock_file);
+=A0=A0=A0 =A0=A0=A0 =A0=A0=A0 }
=A0
=A0=A0=A0=A0 =
=A0=A0=A0 =A0=A0=A0 /* reset program variables */

=A0=A0=A0=A0 =A0=A0=A0 =A0=A0=A0 reset_variables();
@@ -827,10 +832,6 @@=
int main(int argc, char **argv) {
=A0=A0=A0=A0 =A0=A0=A0 =A0=A0=A0 =A0=
=A0=A0 iobroker_destroy(nagios_iobs, IOBROKER_CLOSE_SOCKETS);
=

...[email truncated]...


This post was automatically imported from historical nagios-devel mailing list archives
Original poster: alofgren@op5.com
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