1 /* libunwind - a platform-independent unwind library
2 Copyright (C) 2004 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 #include "unwind_i.h"
27
28 PROTECTED int
unw_is_signal_frame(unw_cursor_t * cursor)29 unw_is_signal_frame (unw_cursor_t *cursor)
30 {
31 #ifdef __linux__
32 struct cursor *c = (struct cursor *) cursor;
33 unw_word_t w0, w1, w2, w3, ip;
34 unw_addr_space_t as;
35 unw_accessors_t *a;
36 void *arg;
37 int ret;
38
39 as = c->dwarf.as;
40 a = unw_get_accessors (as);
41 arg = c->dwarf.as_arg;
42
43 /* Check if IP points at sigreturn() sequence. On Linux, this normally is:
44
45 rt_sigreturn:
46 0x34190000 ldi 0, %r25
47 0x3414015a ldi __NR_rt_sigreturn,%r20
48 0xe4008200 be,l 0x100(%sr2,%r0),%sr0,%r31
49 0x08000240 nop
50
51 When a signal interrupts a system call, the first word is instead:
52
53 0x34190002 ldi 1, %r25
54 */
55 ip = c->dwarf.ip;
56 if (!ip)
57 return 0;
58 if ((ret = (*a->access_mem) (as, ip, &w0, 0, arg)) < 0
59 || (ret = (*a->access_mem) (as, ip + 4, &w1, 0, arg)) < 0
60 || (ret = (*a->access_mem) (as, ip + 8, &w2, 0, arg)) < 0
61 || (ret = (*a->access_mem) (as, ip + 12, &w3, 0, arg)) < 0)
62 {
63 Debug (1, "failed to read sigreturn code (ret=%d)\n", ret);
64 return ret;
65 }
66 ret = ((w0 == 0x34190000 || w0 == 0x34190002)
67 && w1 == 0x3414015a && w2 == 0xe4008200 && w3 == 0x08000240);
68 Debug (1, "(cursor=%p, ip=0x%08lx) -> %d\n", c, (unsigned) ip, ret);
69 return ret;
70 #else
71 printf ("%s: implement me\n", __FUNCTION__);
72 #endif
73 return -UNW_ENOINFO;
74 }
75