Branch
Hash :
a584efaa
Author :
Date :
2024-04-22T14:47:34
Fix potential Null pointer dereference in time-test.c
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/*
* XXX This sample code was once meant to show how to use the basic Libevent
* interfaces, but it never worked on non-Unix platforms, and some of the
* interfaces have changed since it was first written. It should probably
* be removed or replaced with something better.
*
* Compile with:
* cc -I/usr/local/include -o time-test time-test.c -L/usr/local/lib -levent
*/
#include <sys/types.h>
#include <event2/event-config.h>
#include <sys/stat.h>
#ifndef _WIN32
#include <sys/queue.h>
#include <unistd.h>
#endif
#include <time.h>
#ifdef EVENT__HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <signal.h>
#include <event2/event.h>
#include <event2/event_struct.h>
#include <event2/util.h>
#ifdef _WIN32
#include <winsock2.h>
#endif
struct timeval lasttime;
int event_is_persistent;
static void
timeout_cb(evutil_socket_t fd, short event, void *arg)
{
struct timeval newtime, difference;
struct event *timeout = arg;
double elapsed;
evutil_gettimeofday(&newtime, NULL);
evutil_timersub(&newtime, &lasttime, &difference);
elapsed = difference.tv_sec +
(difference.tv_usec / 1.0e6);
printf("timeout_cb called at %d: %.3f seconds elapsed.\n",
(int)newtime.tv_sec, elapsed);
lasttime = newtime;
if (! event_is_persistent) {
struct timeval tv;
evutil_timerclear(&tv);
tv.tv_sec = 2;
event_add(timeout, &tv);
}
}
static void
signal_cb(evutil_socket_t sig, short events, void *user_data)
{
struct event_base *base = user_data;
printf("Caught an interrupt signal; exiting cleanly.\n");
event_base_loopexit(base, NULL);
}
int
main(int argc, char **argv)
{
struct event *timeout,*signal_event;
struct timeval tv;
struct event_base *base;
int flags;
#ifdef _WIN32
WORD wVersionRequested;
WSADATA wsaData;
wVersionRequested = MAKEWORD(2, 2);
(void)WSAStartup(wVersionRequested, &wsaData);
#endif
if (argc == 2 && !strcmp(argv[1], "-p")) {
event_is_persistent = 1;
flags = EV_PERSIST;
} else {
event_is_persistent = 0;
flags = 0;
}
/* Initialize the event library */
base = event_base_new();
/* Initialize one event */
timeout = event_new(base, -1, flags, timeout_cb, event_self_cbarg());
signal_event = evsignal_new(base, SIGINT, signal_cb, (void*)base );
if (timeout == NULL) {
fprintf(stderr, "Couldn't create event");
goto err;
}
if (signal_event == NULL) {
fprintf(stderr, "Couldn't create event");
goto err;
}
evutil_timerclear(&tv);
tv.tv_sec = 2;
event_add(timeout, &tv);
event_add(signal_event, NULL);
evutil_gettimeofday(&lasttime, NULL);
setbuf(stdout, NULL);
setbuf(stderr, NULL);
event_base_dispatch(base);
event_free(signal_event);
event_free(timeout);
event_base_free(base);
return (0);
err:
if (signal_event)
event_free(signal_event);
if (timeout)
event_free(timeout);
if (base)
event_base_free(base);
return (1);
}