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) && 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
52 static void siglongjmp (sigjmp_buf env, int val) UNUSED;
53 #endif
54 #endif /* __GLIBC_PREREQ */
55
56 void
siglongjmp(sigjmp_buf env,int val)57 siglongjmp (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