xref: /netbsd-src/external/bsd/nsd/dist/compat/pselect.c (revision 82d56013d7b633d116a93943de88e08335357a7c)
1 /*
2  * Like select(2) but set the signals to block while waiting in
3  * select.  This version is not entirely race condition safe. Only
4  * operating system support can make it so.
5  */
6 
7 #include <config.h>
8 
9 #include <sys/time.h>
10 #include <sys/types.h>
11 #ifdef HAVE_SYS_SELECT_H
12 #include <sys/select.h>
13 #endif
14 #include <unistd.h>
15 #include <signal.h>
16 
17 int
18 pselect (int n,
19 	 fd_set *readfds,
20 	 fd_set *writefds,
21 	 fd_set *exceptfds,
22 	 const struct timespec *timeout,
23 	 const sigset_t *sigmask)
24 {
25 	int result;
26 	sigset_t saved_sigmask;
27 	struct timeval saved_timeout;
28 
29 	if (sigmask && sigprocmask(SIG_SETMASK, sigmask, &saved_sigmask) == -1)
30 		return -1;
31 
32 	if (timeout) {
33 		saved_timeout.tv_sec = timeout->tv_sec;
34 		saved_timeout.tv_usec = timeout->tv_nsec / 1000;
35 		result = select(n, readfds, writefds, exceptfds, &saved_timeout);
36 	} else {
37 		result = select(n, readfds, writefds, exceptfds, NULL);
38 	}
39 
40 	if (sigmask && sigprocmask(SIG_SETMASK, &saved_sigmask, NULL) == -1)
41 		return -1;
42 
43 	return result;
44 }
45