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dahdi_cfg: Unlink semaphore on early exit.

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If dahdi_cfg is terminated while holding the named semaphore, it is possible to
leave it behind and all subsequenct invocations of dahdi_cfg will block waiting
for it.

Signed-off-by: Shaun Ruffell <sruffell@digium.com>
Signed-off-by: Russ Meyerriecks <rmeyerriecks@digium.com>
This commit is contained in:
Shaun Ruffell 2014-07-07 15:12:57 -05:00 committed by Russ Meyerriecks
parent 64e7c688d3
commit 8045f7f493
1 changed files with 28 additions and 2 deletions
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30
dahdi_cfg.c
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@ -29,6 +29,7 @@
#include <stdio.h>
#include <getopt.h>
#include <signal.h>
#include <string.h>
#include <stdarg.h>
#include <stdlib.h>
@ -1540,15 +1541,27 @@ static int span_restrict(char *str)
return 1;
}
static const char *SEM_NAME = "dahdi_cfg";
static sem_t *lock = SEM_FAILED;
static void signal_handler(int signal)
{
if (SEM_FAILED != lock) {
sem_unlink(SEM_NAME);
}
/* The default handler should have been restored before this handler was
* called, so we can let the "normal" processing finish the cleanup. */
raise(signal);
}
int main(int argc, char *argv[])
{
int c;
char *buf;
char *key, *value;
int x,found;
sem_t *lock = SEM_FAILED;
const char *SEM_NAME = "dahdi_cfg";
int exit_code = 0;
struct sigaction act;
while((c = getopt(argc, argv, "fthc:vsd::C:S:")) != -1) {
switch(c) {
@ -1670,6 +1683,19 @@ finish:
fflush(stdout);
}
sigemptyset(&act.sa_mask);
act.sa_handler = signal_handler;
act.sa_flags = SA_RESETHAND;
if (sigaction(SIGTERM, &act, NULL) == -1) {
perror("Failed to install SIGTERM handler.");
exit(1);
}
if (sigaction(SIGINT, &act, NULL) == -1) {
perror("Failed to install SIGINT handler.");
exit(1);
}
lock = sem_open(SEM_NAME, O_CREAT, O_RDWR, 1);
if (SEM_FAILED == lock) {
perror("Unable to create 'dahdi_cfg' mutex");