src/setjmp/generic/sigaction.c

   1 /*
   2  * Copyright (c) 1999-2017 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 /*
  24  * Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved
  25  *
  26  *      @(#)sigaction.c 1.0
  27  */
  28
  29 #include <stdlib.h>
  30 #include <unistd.h>
  31 #include <signal.h>
  32 #include <sys/signal.h>
  33 #include <errno.h>
  34
  35 // keep in sync with BSD_KERNEL_PRIVATE value in xnu/bsd/sys/signal.h
  36 #define SA_VALIDATE_SIGRETURN_FROM_SIGTRAMP 0x0400
  37
  38 /*
  39  *      Intercept the sigaction syscall and use our signal trampoline
  40  *      as the signal handler instead.  The code here is derived
  41  *      from sigvec in sys/kern_sig.c.
  42  */
  43 extern int __sigaction (int, struct __sigaction * __restrict,
  44                 struct sigaction * __restrict);
  45
  46 int
  47 __platform_sigaction (int sig, const struct sigaction * __restrict nsv,
  48                 struct sigaction * __restrict osv)
  49 {
  50         extern void _sigtramp();
  51         struct __sigaction sa;
  52         struct __sigaction *sap;
  53         int ret;
  54
  55         if (sig <= 0 || sig >= NSIG || sig == SIGKILL || sig == SIGSTOP) {
  56                 errno = EINVAL;
  57                 return (-1);
  58         }
  59         sap = (struct __sigaction *)0;
  60         if (nsv) {
  61                 sa.sa_handler = nsv->sa_handler;
  62                 sa.sa_tramp = _sigtramp;
  63                 sa.sa_mask = nsv->sa_mask;
  64                 sa.sa_flags = nsv->sa_flags | SA_VALIDATE_SIGRETURN_FROM_SIGTRAMP;
  65                 sap = &sa;
  66         }
  67         ret = __sigaction(sig, sap, osv);
  68         return ret;
  69 }