usr/src/lib/libc/port/sys/signalfd.c

   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 }