src/setjmp/generic/sigtramp.c

   1 /*
   2  * Copyright (c) 1999, 2007 Apple 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
  27 #define _XOPEN_SOURCE 600
  28
  29 #import <sys/types.h>
  30 #import <signal.h>
  31 #import <unistd.h>
  32 #import <ucontext.h>
  33 #import <mach/thread_status.h>
  34 #include <TargetConditionals.h>
  35 #import <os/internal.h>
  36
  37 extern int __sigreturn(ucontext_t *, int, uintptr_t);
  38
  39 /*
  40  * sigvec registers _sigtramp as the handler for any signal requiring
  41  * user-mode intervention.  All _sigtramp does is find the real handler,
  42  * calls it, then sigreturn's.
  43  *
  44  * Note that the kernel saves/restores all of our register state.
  45  */
  46
  47 /* On i386, i386/sys/_sigtramp.s defines this. There is no in_sigtramp on arm */
  48 #if defined(__DYNAMIC__) && defined(__x86_64__)
  49 OS_NOEXPORT
  50 int __in_sigtramp = 0;
  51 #endif
  52
  53 /* These defn should match the kernel one */
  54 #define UC_TRAD                 1
  55 #define UC_FLAVOR               30
  56
  57 #define UC_SET_ALT_STACK        0x40000000
  58 #define UC_RESET_ALT_STACK      0x80000000
  59
  60 /*
  61  * Reset the kernel's idea of the use of an alternate stack; this is used by
  62  * both longjmp() and siglongjmp().  Nothing other than this reset is needed,
  63  * since restoring the registers and other operations that would normally be
  64  * done by sigreturn() are handled in user space, so we do not pass a user
  65  * context (in PPC, a user context is not the same as a jmpbuf mcontext, due
  66  * to having more than one set of registers, etc., for the various 32/64 etc.
  67  * contexts)..
  68  */
  69 OS_NOEXPORT
  70 void
  71 _sigunaltstack(int set)
  72 {
  73         /* sigreturn(uctx, ctxstyle); */
  74         /* syscall (SYS_SIGRETURN, uctx, ctxstyle); */
  75         __sigreturn (NULL, (set == SS_ONSTACK) ? UC_SET_ALT_STACK : UC_RESET_ALT_STACK, 0);
  76 }
  77
  78 /* On these architectures, _sigtramp is implemented in assembly to
  79    ensure it matches its DWARF unwind information.  */
  80 #if !defined (__i386__) && !defined (__x86_64__)
  81 OS_NOEXPORT
  82 void
  83 _sigtramp(
  84         union __sigaction_u __sigaction_u,
  85         int                     sigstyle,
  86         int                     sig,
  87         siginfo_t               *sinfo,
  88         ucontext_t              *uctx,
  89         uintptr_t               token
  90 ) {
  91         int ctxstyle = UC_FLAVOR;
  92
  93         if (sigstyle == UC_TRAD)
  94                 sa_handler(sig);
  95         else {
  96 #if TARGET_OS_WATCH
  97                 // <rdar://problem/22016014>
  98                 sa_sigaction(sig, sinfo, NULL);
  99 #else
 100                 sa_sigaction(sig, sinfo, uctx);
 101 #endif
 102         }
 103
 104         /* sigreturn(uctx, ctxstyle); */
 105         /* syscall (SYS_SIGRETURN, uctx, ctxstyle); */
 106         __sigreturn (uctx, ctxstyle, token);
 107         __builtin_trap(); /* __sigreturn returning is a fatal error */
 108 }
 109
 110 #endif /* not ppc nor ppc64 nor i386 nor x86_64 */