1/* libunwind - a platform-independent unwind library
2   Copyright (C) 2003-2005 Hewlett-Packard Co
3	Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
4
5This file is part of libunwind.
6
7Permission is hereby granted, free of charge, to any person obtaining
8a copy of this software and associated documentation files (the
9"Software"), to deal in the Software without restriction, including
10without limitation the rights to use, copy, modify, merge, publish,
11distribute, sublicense, and/or sell copies of the Software, and to
12permit persons to whom the Software is furnished to do so, subject to
13the following conditions:
14
15The above copyright notice and this permission notice shall be
16included in all copies or substantial portions of the Software.
17
18THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
19EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
21NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
22LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
23OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
24WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
25
26#define UNW_LOCAL_ONLY
27
28#include <setjmp.h>
29
30#include "libunwind_i.h"
31#include "jmpbuf.h"
32#include "setjmp_i.h"
33
34#if !defined(_NSIG) && defined(_SIG_MAXSIG)
35# define _NSIG (_SIG_MAXSIG - 1)
36#endif
37
38#if defined(__GLIBC__)
39#if __GLIBC_PREREQ(2, 4)
40
41/* Starting with glibc-2.4, {sig,}setjmp in GLIBC obfuscates the
42   register values in jmp_buf by XORing them with a "random"
43   canary value.
44
45   This makes it impossible to implement longjmp, as we
46   can never match wp[JB_SP], unless we decode the canary first.
47
48   Doing so is possible, but doesn't appear to be worth the trouble,
49   so we simply defer to glibc siglongjmp here.  */
50
51#define siglongjmp __nonworking_siglongjmp
52static void siglongjmp (sigjmp_buf env, int val) UNUSED;
53#endif
54#endif /* __GLIBC_PREREQ */
55
56void
57siglongjmp (sigjmp_buf env, int val)
58{
59  unw_word_t *wp = (unw_word_t *) env;
60  extern int _UI_siglongjmp_cont;
61  extern int _UI_longjmp_cont;
62  unw_context_t uc;
63  unw_cursor_t c;
64  unw_word_t sp;
65  int *cont;
66
67  if (unw_getcontext (&uc) < 0 || unw_init_local (&c, &uc) < 0)
68    abort ();
69
70  do
71    {
72      if (unw_get_reg (&c, UNW_REG_SP, &sp) < 0)
73	abort ();
74#ifdef __FreeBSD__
75      if (sp != wp[JB_SP] + sizeof(unw_word_t))
76#else
77      if (sp != wp[JB_SP])
78#endif
79	continue;
80
81      if (!bsp_match (&c, wp))
82	continue;
83
84      /* found the right frame: */
85
86      /* default to resuming without restoring signal-mask */
87      cont = &_UI_longjmp_cont;
88
89      /* Order of evaluation is important here: if unw_resume()
90	 restores signal mask, we must set it up appropriately, even
91	 if wp[JB_MASK_SAVED] is FALSE.  */
92      if (!resume_restores_sigmask (&c, wp) && wp[JB_MASK_SAVED])
93	{
94	  /* sigmask was saved */
95#if defined(__linux__)
96	  if (UNW_NUM_EH_REGS < 4 || _NSIG > 16 * sizeof (unw_word_t))
97	    /* signal mask doesn't fit into EH arguments and we can't
98	       put it on the stack without overwriting something
99	       else... */
100	    abort ();
101	  else
102	    if (unw_set_reg (&c, UNW_REG_EH + 2, wp[JB_MASK]) < 0
103		|| (_NSIG > 8 * sizeof (unw_word_t)
104		    && unw_set_reg (&c, UNW_REG_EH + 3, wp[JB_MASK + 1]) < 0))
105	      abort ();
106#elif defined(__FreeBSD__)
107	  if (unw_set_reg (&c, UNW_REG_EH + 2, &wp[JB_MASK]) < 0)
108	      abort();
109#else
110#error Port me
111#endif
112	  cont = &_UI_siglongjmp_cont;
113	}
114
115      if (unw_set_reg (&c, UNW_REG_EH + 0, wp[JB_RP]) < 0
116	  || unw_set_reg (&c, UNW_REG_EH + 1, val) < 0
117	  || unw_set_reg (&c, UNW_REG_IP, (unw_word_t) (uintptr_t) cont))
118	abort ();
119
120      unw_resume (&c);
121
122      abort ();
123    }
124  while (unw_step (&c) > 0);
125
126  abort ();
127}
128