1 /* libunwind - a platform-independent unwind library 2 Copyright (C) 2010, 2011 by FERMI NATIONAL ACCELERATOR LABORATORY 3 4 Permission is hereby granted, free of charge, to any person obtaining 5 a copy of this software and associated documentation files (the 6 "Software"), to deal in the Software without restriction, including 7 without limitation the rights to use, copy, modify, merge, publish, 8 distribute, sublicense, and/or sell copies of the Software, and to 9 permit persons to whom the Software is furnished to do so, subject to 10 the following conditions: 11 12 The above copyright notice and this permission notice shall be 13 included in all copies or substantial portions of the Software. 14 15 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 16 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 17 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 18 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE 19 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION 20 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION 21 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ 22 23 #ifdef HAVE_CONFIG_H 24 # include "config.h" 25 #endif 26 27 #include "compiler.h" 28 29 #include <errno.h> 30 #if HAVE_EXECINFO_H 31 # include <execinfo.h> 32 #else 33 extern int backtrace (void **, int); 34 #endif 35 #include <signal.h> 36 #include <stdio.h> 37 #include <stdlib.h> 38 #include <string.h> 39 #include <unistd.h> 40 #include <libunwind.h> 41 42 #define panic(args...) \ 43 { fprintf (stderr, args); exit (-1); } 44 45 #define SIG_STACK_SIZE 0x100000 46 47 int verbose; 48 int num_errors; 49 50 /* These variables are global because they 51 * cause the signal stack to overflow */ 52 char buf[512], name[256]; 53 void *addresses[3][128]; 54 unw_cursor_t cursor; 55 unw_context_t uc; 56 57 static void 58 do_backtrace (void) 59 { 60 unw_word_t ip; 61 int ret = -UNW_ENOINFO; 62 int depth = 0; 63 int i, n, m; 64 65 if (verbose) 66 printf ("\tnormal trace:\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 addresses[0][depth] = (void *) ip; 76 } 77 while ((ret = unw_step (&cursor)) > 0 && ++depth < 128); 78 79 if (ret < 0) 80 { 81 unw_get_reg (&cursor, UNW_REG_IP, &ip); 82 printf ("FAILURE: unw_step() returned %d for ip=%lx\n", ret, (long) ip); 83 ++num_errors; 84 } 85 86 if (verbose) 87 for (i = 0; i < depth; ++i) 88 printf ("\t #%-3d ip=%p\n", i, addresses[0][i]); 89 90 if (verbose) 91 printf ("\n\tvia backtrace():\n"); 92 93 n = backtrace (addresses[1], 128); 94 95 if (verbose) 96 for (i = 0; i < n; ++i) 97 printf ("\t #%-3d ip=%p\n", i, addresses[1][i]); 98 99 if (verbose) 100 printf ("\n\tvia unw_backtrace():\n"); 101 102 m = unw_backtrace (addresses[2], 128); 103 104 if (verbose) 105 for (i = 0; i < m; ++i) 106 printf ("\t #%-3d ip=%p\n", i, addresses[2][i]); 107 108 if (m != depth+1) 109 { 110 printf ("FAILURE: unw_step() loop and unw_backtrace() depths differ: %d vs. %d\n", depth, m); 111 ++num_errors; 112 } 113 114 if (n != depth+1) 115 { 116 printf ("FAILURE: unw_step() loop and backtrace() depths differ: %d vs. %d\n", depth, n); 117 ++num_errors; 118 } 119 120 if (n == m) 121 for (i = 1; i < n; ++i) 122 /* Allow one in difference in comparison, trace returns adjusted addresses. */ 123 if (labs((unw_word_t) addresses[1][i] - (unw_word_t) addresses[2][i]) > 1) 124 { 125 printf ("FAILURE: backtrace() and unw_backtrace() addresses differ at %d: %p vs. %p\n", 126 i, addresses[1][n], addresses[2][n]); 127 ++num_errors; 128 } 129 130 if (n == depth+1) 131 for (i = 1; i < depth; ++i) 132 /* Allow one in difference in comparison, trace returns adjusted addresses. */ 133 if (labs((unw_word_t) addresses[0][i] - (unw_word_t) addresses[1][i]) > 1) 134 { 135 printf ("FAILURE: unw_step() loop and backtrace() addresses differ at %d: %p vs. %p\n", 136 i, addresses[0][n], addresses[1][n]); 137 ++num_errors; 138 } 139 } 140 141 void 142 foo (long val UNUSED) 143 { 144 do_backtrace (); 145 } 146 147 void 148 bar (long v) 149 { 150 extern long f (long); 151 int arr[v]; 152 153 /* This is a vain attempt to use up lots of registers to force 154 the frame-chain info to be saved on the memory stack on ia64. 155 It happens to work with gcc v3.3.4 and gcc v3.4.1 but perhaps 156 not with any other compiler. */ 157 foo (f (arr[0]) + (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 + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) 164 + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) 165 + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) 166 + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) 167 + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) 168 + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) 169 + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) 170 + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) 171 + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) 172 + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) 173 + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + (f (v) + f (v)) 174 )))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))) 175 ))))))))))))))))))))))))))))))))))))))))))))))))))))))); 176 } 177 178 void 179 sighandler (int signal, void *siginfo UNUSED, void *context) 180 { 181 ucontext_t *uc UNUSED; 182 int sp; 183 184 uc = context; 185 186 if (verbose) 187 { 188 printf ("sighandler: got signal %d, sp=%p", signal, &sp); 189 #if UNW_TARGET_IA64 190 # if defined(__linux__) 191 printf (" @ %lx", uc->uc_mcontext.sc_ip); 192 # else 193 { 194 uint16_t reason; 195 uint64_t ip; 196 197 __uc_get_reason (uc, &reason); 198 __uc_get_ip (uc, &ip); 199 printf (" @ %lx (reason=%d)", ip, reason); 200 } 201 # endif 202 #elif UNW_TARGET_X86 203 #if defined __linux__ 204 printf (" @ %lx", (unsigned long) uc->uc_mcontext.gregs[REG_EIP]); 205 #elif defined __FreeBSD__ 206 printf (" @ %lx", (unsigned long) uc->uc_mcontext.mc_eip); 207 #endif 208 #elif UNW_TARGET_X86_64 209 #if defined __linux__ 210 printf (" @ %lx", (unsigned long) uc->uc_mcontext.gregs[REG_RIP]); 211 #elif defined __FreeBSD__ 212 printf (" @ %lx", (unsigned long) uc->uc_mcontext.mc_rip); 213 #endif 214 #elif defined UNW_TARGET_ARM 215 printf (" @ %lx", (unsigned long) uc->uc_mcontext.arm_pc); 216 #endif 217 printf ("\n"); 218 } 219 do_backtrace(); 220 } 221 222 int 223 main (int argc, char **argv UNUSED) 224 { 225 struct sigaction act; 226 stack_t stk; 227 228 verbose = (argc > 1); 229 230 if (verbose) 231 printf ("Normal backtrace:\n"); 232 233 bar (1); 234 235 memset (&act, 0, sizeof (act)); 236 act.sa_handler = (void (*)(int)) sighandler; 237 act.sa_flags = SA_SIGINFO; 238 if (sigaction (SIGTERM, &act, NULL) < 0) 239 panic ("sigaction: %s\n", strerror (errno)); 240 241 if (verbose) 242 printf ("\nBacktrace across signal handler:\n"); 243 kill (getpid (), SIGTERM); 244 245 if (verbose) 246 printf ("\nBacktrace across signal handler on alternate stack:\n"); 247 stk.ss_sp = malloc (SIG_STACK_SIZE); 248 if (!stk.ss_sp) 249 panic ("failed to allocate %u bytes\n", SIG_STACK_SIZE); 250 stk.ss_size = SIG_STACK_SIZE; 251 stk.ss_flags = 0; 252 if (sigaltstack (&stk, NULL) < 0) 253 panic ("sigaltstack: %s\n", strerror (errno)); 254 255 memset (&act, 0, sizeof (act)); 256 act.sa_handler = (void (*)(int)) sighandler; 257 act.sa_flags = SA_ONSTACK | SA_SIGINFO; 258 if (sigaction (SIGTERM, &act, NULL) < 0) 259 panic ("sigaction: %s\n", strerror (errno)); 260 kill (getpid (), SIGTERM); 261 262 if (num_errors > 0) 263 { 264 fprintf (stderr, "FAILURE: detected %d errors\n", num_errors); 265 exit (-1); 266 } 267 268 if (verbose) 269 printf ("SUCCESS.\n"); 270 271 signal (SIGTERM, SIG_DFL); 272 stk.ss_flags = SS_DISABLE; 273 sigaltstack (&stk, NULL); 274 free (stk.ss_sp); 275 276 return 0; 277 } 278
