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 <ucontext.h>
41 #include <unistd.h>
42 #include <libunwind.h>
43
44 #define panic(args...) \
45 { fprintf (stderr, args); exit (-1); }
46
47 #define SIG_STACK_SIZE 0x100000
48
49 int verbose;
50 int num_errors;
51
52 /* These variables are global because they
53 * cause the signal stack to overflow */
54 char buf[512], name[256];
55 unw_cursor_t cursor;
56 unw_context_t uc;
57
58 static void
do_backtrace(void)59 do_backtrace (void)
60 {
61 unw_word_t ip, sp, off;
62 unw_proc_info_t pi;
63 int ret;
64
65 if (verbose)
66 printf ("\texplicit backtrace:\n");
67
68 unw_getcontext (&uc);
69 if (unw_init_local (&cursor, &uc) < 0)
70 panic ("unw_init_local failed!\n");
71
72 do
73 {
74 unw_get_reg (&cursor, UNW_REG_IP, &ip);
75 unw_get_reg (&cursor, UNW_REG_SP, &sp);
76 buf[0] = '\0';
77 if (unw_get_proc_name (&cursor, name, sizeof (name), &off) == 0)
78 {
79 if (off)
80 snprintf (buf, sizeof (buf), "<%s+0x%lx>", name, (long) off);
81 else
82 snprintf (buf, sizeof (buf), "<%s>", name);
83 }
84 if (verbose)
85 {
86 printf ("%016lx %-32s (sp=%016lx)\n", (long) ip, buf, (long) sp);
87
88 if (unw_get_proc_info (&cursor, &pi) == 0)
89 {
90 printf ("\tproc=0x%lx-0x%lx\n\thandler=0x%lx lsda=0x%lx gp=0x%lx",
91 (long) pi.start_ip, (long) pi.end_ip,
92 (long) pi.handler, (long) pi.lsda, (long) pi.gp);
93 }
94
95 #if UNW_TARGET_IA64
96 {
97 unw_word_t bsp;
98
99 unw_get_reg (&cursor, UNW_IA64_BSP, &bsp);
100 printf (" bsp=%lx", bsp);
101 }
102 #endif
103 printf ("\n");
104 }
105
106 ret = unw_step (&cursor);
107 if (ret < 0)
108 {
109 unw_get_reg (&cursor, UNW_REG_IP, &ip);
110 printf ("FAILURE: unw_step() returned %d for ip=%lx\n",
111 ret, (long) ip);
112 ++num_errors;
113 }
114 }
115 while (ret > 0);
116
117 {
118 void *buffer[20];
119 int i, n;
120
121 if (verbose)
122 printf ("\n\tvia backtrace():\n");
123 n = backtrace (buffer, 20);
124 if (verbose)
125 for (i = 0; i < n; ++i)
126 printf ("[%d] ip=%p\n", i, buffer[i]);
127 }
128 }
129
130 void
foo(long val UNUSED)131 foo (long val UNUSED)
132 {
133 do_backtrace ();
134 }
135
136 void
bar(long v)137 bar (long v)
138 {
139 extern long f (long);
140 int arr[v];
141
142 /* This is a vain attempt to use up lots of registers to force
143 the frame-chain info to be saved on the memory stack on ia64.
144 It happens to work with gcc v3.3.4 and gcc v3.4.1 but perhaps
145 not with any other compiler. */
146 foo (f (arr[0]) + (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 + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + f (v))
163 ))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))
164 )))))))))))))))))))))))))))))))))))))))))))))))))))))));
165 }
166
167 void
sighandler(int signal,void * siginfo UNUSED,void * context)168 sighandler (int signal, void *siginfo UNUSED, void *context)
169 {
170 ucontext_t *uc UNUSED;
171 int sp;
172
173 uc = context;
174
175 if (verbose)
176 {
177 printf ("sighandler: got signal %d, sp=%p", signal, &sp);
178 #if UNW_TARGET_IA64
179 # if defined(__linux__) || defined __sun
180 printf (" @ %lx", uc->uc_mcontext.sc_ip);
181 # else
182 {
183 uint16_t reason;
184 uint64_t ip;
185
186 __uc_get_reason (uc, &reason);
187 __uc_get_ip (uc, &ip);
188 printf (" @ %lx (reason=%d)", ip, reason);
189 }
190 # endif
191 #elif UNW_TARGET_X86
192 #if defined __linux__ || defined __sun
193 printf (" @ %lx", (unsigned long) uc->uc_mcontext.gregs[REG_EIP]);
194 #elif defined __FreeBSD__
195 printf (" @ %lx", (unsigned long) uc->uc_mcontext.mc_eip);
196 #endif
197 #elif UNW_TARGET_X86_64
198 #if defined __linux__ || defined __sun
199 printf (" @ %lx", (unsigned long) uc->uc_mcontext.gregs[REG_RIP]);
200 #elif defined __FreeBSD__
201 printf (" @ %lx", (unsigned long) uc->uc_mcontext.mc_rip);
202 #endif
203 #endif
204 printf ("\n");
205 }
206 do_backtrace();
207 }
208
209 int
main(int argc,char ** argv UNUSED)210 main (int argc, char **argv UNUSED)
211 {
212 struct sigaction act;
213 stack_t stk;
214
215 verbose = (argc > 1);
216
217 if (verbose)
218 printf ("Normal backtrace:\n");
219
220 bar (1);
221
222 memset (&act, 0, sizeof (act));
223 act.sa_handler = (void (*)(int)) sighandler;
224 act.sa_flags = SA_SIGINFO;
225 if (sigaction (SIGTERM, &act, NULL) < 0)
226 panic ("sigaction: %s\n", strerror (errno));
227
228 if (verbose)
229 printf ("\nBacktrace across signal handler:\n");
230 kill (getpid (), SIGTERM);
231
232 if (verbose)
233 printf ("\nBacktrace across signal handler on alternate stack:\n");
234 stk.ss_sp = malloc (SIG_STACK_SIZE);
235 if (!stk.ss_sp)
236 panic ("failed to allocate %u bytes\n", SIG_STACK_SIZE);
237 stk.ss_size = SIG_STACK_SIZE;
238 stk.ss_flags = 0;
239 if (sigaltstack (&stk, NULL) < 0)
240 panic ("sigaltstack: %s\n", strerror (errno));
241
242 memset (&act, 0, sizeof (act));
243 act.sa_handler = (void (*)(int)) sighandler;
244 act.sa_flags = SA_ONSTACK | SA_SIGINFO;
245 if (sigaction (SIGTERM, &act, NULL) < 0)
246 panic ("sigaction: %s\n", strerror (errno));
247 kill (getpid (), SIGTERM);
248
249 if (num_errors > 0)
250 {
251 fprintf (stderr, "FAILURE: detected %d errors\n", num_errors);
252 exit (-1);
253 }
254 if (verbose)
255 printf ("SUCCESS.\n");
256
257 signal (SIGTERM, SIG_DFL);
258 stk.ss_flags = SS_DISABLE;
259 sigaltstack (&stk, NULL);
260 free (stk.ss_sp);
261
262 return 0;
263 }
264