1 /* libunwind - a platform-independent unwind library
2 Copyright (C) 2001-2004 Hewlett-Packard Co
3 Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
4
5 Permission is hereby granted, free of charge, to any person obtaining
6 a copy of this software and associated documentation files (the
7 "Software"), to deal in the Software without restriction, including
8 without limitation the rights to use, copy, modify, merge, publish,
9 distribute, sublicense, and/or sell copies of the Software, and to
10 permit persons to whom the Software is furnished to do so, subject to
11 the following conditions:
12
13 The above copyright notice and this permission notice shall be
14 included in all copies or substantial portions of the Software.
15
16 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
17 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
18 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
19 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
20 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
21 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
22 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
23
24 #ifdef HAVE_CONFIG_H
25 # include "config.h"
26 #endif
27
28 #include "compiler.h"
29
30 #include <errno.h>
31 #if HAVE_EXECINFO_H
32 # include <execinfo.h>
33 #else
34 extern int backtrace (void **, int);
35 #endif
36 #include <signal.h>
37 #include <stdio.h>
38 #include <stdlib.h>
39 #include <string.h>
40 #include <unistd.h>
41 #include <libunwind.h>
42
43 #define panic(args...) \
44 { fprintf (stderr, args); exit (-1); }
45
46 #define SIG_STACK_SIZE 0x100000
47
48 int verbose;
49 int num_errors;
50
51 /* These variables are global because they
52 * cause the signal stack to overflow */
53 char buf[512], name[256];
54 unw_cursor_t cursor;
55 unw_context_t uc;
56
57 static void
do_backtrace(void)58 do_backtrace (void)
59 {
60 unw_word_t ip, sp, off;
61 unw_proc_info_t pi;
62 int ret;
63
64 if (verbose)
65 printf ("\texplicit backtrace:\n");
66
67 unw_getcontext (&uc);
68 if (unw_init_local (&cursor, &uc) < 0)
69 panic ("unw_init_local failed!\n");
70
71 do
72 {
73 unw_get_reg (&cursor, UNW_REG_IP, &ip);
74 unw_get_reg (&cursor, UNW_REG_SP, &sp);
75 buf[0] = '\0';
76 if (unw_get_proc_name (&cursor, name, sizeof (name), &off) == 0)
77 {
78 if (off)
79 snprintf (buf, sizeof (buf), "<%s+0x%lx>", name, (long) off);
80 else
81 snprintf (buf, sizeof (buf), "<%s>", name);
82 }
83 if (verbose)
84 {
85 printf ("%016lx %-32s (sp=%016lx)\n", (long) ip, buf, (long) sp);
86
87 if (unw_get_proc_info (&cursor, &pi) == 0)
88 {
89 printf ("\tproc=0x%lx-0x%lx\n\thandler=0x%lx lsda=0x%lx gp=0x%lx",
90 (long) pi.start_ip, (long) pi.end_ip,
91 (long) pi.handler, (long) pi.lsda, (long) pi.gp);
92 }
93
94 #if UNW_TARGET_IA64
95 {
96 unw_word_t bsp;
97
98 unw_get_reg (&cursor, UNW_IA64_BSP, &bsp);
99 printf (" bsp=%lx", bsp);
100 }
101 #endif
102 printf ("\n");
103 }
104
105 ret = unw_step (&cursor);
106 if (ret < 0)
107 {
108 unw_get_reg (&cursor, UNW_REG_IP, &ip);
109 printf ("FAILURE: unw_step() returned %d for ip=%lx\n",
110 ret, (long) ip);
111 ++num_errors;
112 }
113 }
114 while (ret > 0);
115
116 {
117 void *buffer[20];
118 int i, n;
119
120 if (verbose)
121 printf ("\n\tvia backtrace():\n");
122 n = backtrace (buffer, 20);
123 if (verbose)
124 for (i = 0; i < n; ++i)
125 printf ("[%d] ip=%p\n", i, buffer[i]);
126 }
127 }
128
129 void
foo(long val UNUSED)130 foo (long val UNUSED)
131 {
132 do_backtrace ();
133 }
134
135 void
bar(long v)136 bar (long v)
137 {
138 extern long f (long);
139 int arr[v];
140
141 /* This is a vain attempt to use up lots of registers to force
142 the frame-chain info to be saved on the memory stack on ia64.
143 It happens to work with gcc v3.3.4 and gcc v3.4.1 but perhaps
144 not with any other compiler. */
145 foo (f (arr[0]) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v)
146 + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v)
147 + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v)
148 + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v)
149 + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v)
150 + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v)
151 + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v)
152 + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v)
153 + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v)
154 + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v)
155 + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v)
156 + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v)
157 + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v)
158 + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v)
159 + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v)
160 + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v)
161 + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + f (v))
162 ))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))
163 )))))))))))))))))))))))))))))))))))))))))))))))))))))));
164 }
165
166 void
sighandler(int signal,void * siginfo UNUSED,void * context)167 sighandler (int signal, void *siginfo UNUSED, void *context)
168 {
169 ucontext_t *uc UNUSED;
170 int sp;
171
172 uc = context;
173
174 if (verbose)
175 {
176 printf ("sighandler: got signal %d, sp=%p", signal, &sp);
177 #if UNW_TARGET_IA64
178 # if defined(__linux__)
179 printf (" @ %lx", uc->uc_mcontext.sc_ip);
180 # else
181 {
182 uint16_t reason;
183 uint64_t ip;
184
185 __uc_get_reason (uc, &reason);
186 __uc_get_ip (uc, &ip);
187 printf (" @ %lx (reason=%d)", ip, reason);
188 }
189 # endif
190 #elif UNW_TARGET_X86
191 #if defined __linux__
192 printf (" @ %lx", (unsigned long) uc->uc_mcontext.gregs[REG_EIP]);
193 #elif defined __FreeBSD__
194 printf (" @ %lx", (unsigned long) uc->uc_mcontext.mc_eip);
195 #endif
196 #elif UNW_TARGET_X86_64
197 #if defined __linux__
198 printf (" @ %lx", (unsigned long) uc->uc_mcontext.gregs[REG_RIP]);
199 #elif defined __FreeBSD__
200 printf (" @ %lx", (unsigned long) uc->uc_mcontext.mc_rip);
201 #endif
202 #endif
203 printf ("\n");
204 }
205 do_backtrace();
206 }
207
208 int
main(int argc,char ** argv UNUSED)209 main (int argc, char **argv UNUSED)
210 {
211 struct sigaction act;
212 stack_t stk;
213
214 verbose = (argc > 1);
215
216 if (verbose)
217 printf ("Normal backtrace:\n");
218
219 bar (1);
220
221 memset (&act, 0, sizeof (act));
222 act.sa_handler = (void (*)(int)) sighandler;
223 act.sa_flags = SA_SIGINFO;
224 if (sigaction (SIGTERM, &act, NULL) < 0)
225 panic ("sigaction: %s\n", strerror (errno));
226
227 if (verbose)
228 printf ("\nBacktrace across signal handler:\n");
229 kill (getpid (), SIGTERM);
230
231 if (verbose)
232 printf ("\nBacktrace across signal handler on alternate stack:\n");
233 stk.ss_sp = malloc (SIG_STACK_SIZE);
234 if (!stk.ss_sp)
235 panic ("failed to allocate %u bytes\n", SIG_STACK_SIZE);
236 stk.ss_size = SIG_STACK_SIZE;
237 stk.ss_flags = 0;
238 if (sigaltstack (&stk, NULL) < 0)
239 panic ("sigaltstack: %s\n", strerror (errno));
240
241 memset (&act, 0, sizeof (act));
242 act.sa_handler = (void (*)(int)) sighandler;
243 act.sa_flags = SA_ONSTACK | SA_SIGINFO;
244 if (sigaction (SIGTERM, &act, NULL) < 0)
245 panic ("sigaction: %s\n", strerror (errno));
246 kill (getpid (), SIGTERM);
247
248 if (num_errors > 0)
249 {
250 fprintf (stderr, "FAILURE: detected %d errors\n", num_errors);
251 exit (-1);
252 }
253 if (verbose)
254 printf ("SUCCESS.\n");
255
256 signal (SIGTERM, SIG_DFL);
257 stk.ss_flags = SS_DISABLE;
258 sigaltstack (&stk, NULL);
259 free (stk.ss_sp);
260
261 return 0;
262 }
263