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
5 This file is part of libunwind.
6
7 Permission is hereby granted, free of charge, to any person obtaining
8 a copy of this software and associated documentation files (the
9 "Software"), to deal in the Software without restriction, including
10 without limitation the rights to use, copy, modify, merge, publish,
11 distribute, sublicense, and/or sell copies of the Software, and to
12 permit persons to whom the Software is furnished to do so, subject to
13 the following conditions:
14
15 The above copyright notice and this permission notice shall be
16 included in all copies or substantial portions of the Software.
17
18 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
19 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
21 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
22 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
23 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
24 WITH 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)
35 # if defined(_SIG_MAXSIG)
36 # define _NSIG (_SIG_MAXSIG - 1)
37 # elif defined(NSIG)
38 # define _NSIG NSIG
39 # endif
40 #endif
41
42 #if defined(__GLIBC__)
43 #if __GLIBC_PREREQ(2, 4)
44
45 /* Starting with glibc-2.4, {sig,}setjmp in GLIBC obfuscates the
46 register values in jmp_buf by XORing them with a "random"
47 canary value.
48
49 This makes it impossible to implement longjmp, as we
50 can never match wp[JB_SP], unless we decode the canary first.
51
52 Doing so is possible, but doesn't appear to be worth the trouble,
53 so we simply defer to glibc siglongjmp here. */
54
55 #define siglongjmp __nonworking_siglongjmp
56 static void siglongjmp (sigjmp_buf env, int val) UNUSED;
57 #endif
58 #endif /* __GLIBC_PREREQ */
59
60 void
siglongjmp(sigjmp_buf env,int val)61 siglongjmp (sigjmp_buf env, int val)
62 {
63 unw_word_t *wp = (unw_word_t *) env;
64 extern int _UI_siglongjmp_cont;
65 extern int _UI_longjmp_cont;
66 unw_context_t uc;
67 unw_cursor_t c;
68 unw_word_t sp;
69 int *cont;
70
71 if (unw_getcontext (&uc) < 0 || unw_init_local (&c, &uc) < 0)
72 abort ();
73
74 do
75 {
76 if (unw_get_reg (&c, UNW_REG_SP, &sp) < 0)
77 abort ();
78 #ifdef __FreeBSD__
79 if (sp != wp[JB_SP] + sizeof(unw_word_t))
80 #else
81 if (sp != wp[JB_SP])
82 #endif
83 continue;
84
85 if (!bsp_match (&c, wp))
86 continue;
87
88 /* found the right frame: */
89
90 /* default to resuming without restoring signal-mask */
91 cont = &_UI_longjmp_cont;
92
93 /* Order of evaluation is important here: if unw_resume()
94 restores signal mask, we must set it up appropriately, even
95 if wp[JB_MASK_SAVED] is FALSE. */
96 if (!resume_restores_sigmask (&c, wp) && wp[JB_MASK_SAVED])
97 {
98 /* sigmask was saved */
99 #if defined(__linux__) || defined(__sun)
100 if (UNW_NUM_EH_REGS < 4 || _NSIG > 16 * sizeof (unw_word_t))
101 /* signal mask doesn't fit into EH arguments and we can't
102 put it on the stack without overwriting something
103 else... */
104 abort ();
105 else
106 if (unw_set_reg (&c, UNW_REG_EH + 2, wp[JB_MASK]) < 0
107 || (_NSIG > 8 * sizeof (unw_word_t)
108 && unw_set_reg (&c, UNW_REG_EH + 3, wp[JB_MASK + 1]) < 0))
109 abort ();
110 #elif defined(__FreeBSD__)
111 if (unw_set_reg (&c, UNW_REG_EH + 2, &wp[JB_MASK]) < 0)
112 abort();
113 #else
114 #error Port me
115 #endif
116 cont = &_UI_siglongjmp_cont;
117 }
118
119 if (unw_set_reg (&c, UNW_REG_EH + 0, wp[JB_RP]) < 0
120 || unw_set_reg (&c, UNW_REG_EH + 1, val) < 0
121 || unw_set_reg (&c, UNW_REG_IP, (unw_word_t) (uintptr_t) cont))
122 abort ();
123
124 unw_resume (&c);
125
126 abort ();
127 }
128 while (unw_step (&c) > 0);
129
130 abort ();
131 }
132