posix-timer: take into account that sival_ptr can be NULL (v3)

ID: 0
signal: 26/          (null)
notify: signal/pid.5954
ClockID: 1

fscanf "%p" doesn't handle "(null)".

https://bugzilla.openvz.org/show_bug.cgi?id=2894

v2: make the original scanf be %d/%s and then additionally
    parse the obtained string
v3: don't use strstr
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

proc_parse.c

@@ -1315,16 +1315,17 @@ int parse_posix_timers(pid_t pid, struct proc_posix_timers_stat *args)
 	}
 
 	while (1) {
+		char pbuf[17]; /* 16 + eol */
 		timer = xzalloc(sizeof(struct proc_posix_timer));
 		if (timer == NULL)
 			goto err;
 
 		ret = fscanf(file, "ID: %ld\n"
-				   "signal: %d/%p\n"
+				   "signal: %d/%16s\n"
 				   "notify: %6[a-z]/%3[a-z].%d\n"
 				   "ClockID: %d\n",
 				&timer->spt.it_id,
-				&timer->spt.si_signo, &timer->spt.sival_ptr,
+				&timer->spt.si_signo, pbuf,
 				sigpid, tidpid, &pid_t,
 				&timer->spt.clock_id);
 		if (ret != 7) {
@@ -1335,6 +1336,14 @@ int parse_posix_timers(pid_t pid, struct proc_posix_timers_stat *args)
 			goto err;
 		}
 
+		timer->spt.sival_ptr = NULL;
+		if (sscanf(pbuf, "%p", &timer->spt.sival_ptr) != 1 &&
+		    strcmp(pbuf, "(null)")) {
+			pr_err("Unable to parse '%s'\n", pbuf);
+			xfree(timer);
+			goto err;
+		}
+
 		if ( tidpid[0] == 't') {
 			timer->spt.it_sigev_notify = SIGEV_THREAD_ID;
 		} else {