xref: /illumos-gate/usr/src/lib/libc/port/sys/signalfd.c (revision 0250c53ad267726f2438e3c6556199a0bbf588a2)
1 /*
2  * This file and its contents are supplied under the terms of the
3  * Common Development and Distribution License ("CDDL"), version 1.0.
4  * You may only use this file in accordance with the terms of version
5  * 1.0 of the CDDL.
6  *
7  * A full copy of the text of the CDDL should have accompanied this
8  * source.  A copy of the CDDL is also available via the Internet at
9  * http://www.illumos.org/license/CDDL.
10  */
11 
12 /*
13  * Copyright 2015, Joyent, Inc.
14  */
15 
16 #include <sys/signalfd.h>
17 #include <sys/stat.h>
18 #include <unistd.h>
19 #include <errno.h>
20 #include <fcntl.h>
21 
22 int
23 signalfd(int fd, const sigset_t *mask, int flags)
24 {
25 	int origfd = fd;
26 
27 	if (fd == -1) {
28 		int oflags = O_RDONLY;
29 
30 		if (flags & ~(SFD_NONBLOCK | SFD_CLOEXEC)) {
31 			errno = EINVAL;
32 			return (-1);
33 		}
34 
35 		if (flags & SFD_NONBLOCK)
36 			oflags |= O_NONBLOCK;
37 
38 		if (flags & SFD_CLOEXEC)
39 			oflags |= O_CLOEXEC;
40 
41 		if ((fd = open("/dev/signalfd", oflags)) < 0)
42 			return (-1);
43 	}
44 
45 	if (ioctl(fd, SIGNALFDIOC_MASK, mask) != 0) {
46 		if (origfd == -1) {
47 			int old = errno;
48 			(void) close(fd);
49 			errno = old;
50 		}
51 		/*
52 		 * Trying to modify an existing sigfd so if this failed
53 		 * it's because it's not a valid fd or not a sigfd. ioctl
54 		 * returns the correct errno for these cases.
55 		 */
56 		return (-1);
57 	}
58 
59 	return (fd);
60 }
61