libbacktrace/fileline.c

   1 /* fileline.c -- Get file and line number information in a backtrace.
   2    Copyright (C) 2012-2024 Free Software Foundation, Inc.
   3    Written by Ian Lance Taylor, Google.
   4
   5 Redistribution and use in source and binary forms, with or without
   6 modification, are permitted provided that the following conditions are
   7 met:
   8
   9     (1) Redistributions of source code must retain the above copyright
  10     notice, this list of conditions and the following disclaimer.
  11
  12     (2) Redistributions in binary form must reproduce the above copyright
  13     notice, this list of conditions and the following disclaimer in
  14     the documentation and/or other materials provided with the
  15     distribution.
  16
  17     (3) The name of the author may not be used to
  18     endorse or promote products derived from this software without
  19     specific prior written permission.
  20
  21 THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  22 IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  23 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  24 DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
  25 INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  26 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  27 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28 HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  29 STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  30 IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  31 POSSIBILITY OF SUCH DAMAGE.  */
  32
  33 #include "config.h"
  34
  35 #include <sys/types.h>
  36 #include <sys/stat.h>
  37 #include <errno.h>
  38 #include <fcntl.h>
  39 #include <stdlib.h>
  40 #include <unistd.h>
  41
  42 #if defined (HAVE_KERN_PROC_ARGS) || defined (HAVE_KERN_PROC)
  43 #include <sys/sysctl.h>
  44 #endif
  45
  46 #ifdef HAVE_MACH_O_DYLD_H
  47 #include <mach-o/dyld.h>
  48 #endif
  49
  50 #ifdef HAVE_WINDOWS_H
  51 #ifndef WIN32_MEAN_AND_LEAN
  52 #define WIN32_MEAN_AND_LEAN
  53 #endif
  54
  55 #ifndef NOMINMAX
  56 #define NOMINMAX
  57 #endif
  58
  59 #include <windows.h>
  60 #endif
  61
  62 #include "backtrace.h"
  63 #include "internal.h"
  64
  65 #ifndef HAVE_GETEXECNAME
  66 #define getexecname() NULL
  67 #endif
  68
  69 #if !defined (HAVE_KERN_PROC_ARGS) && !defined (HAVE_KERN_PROC)
  70
  71 #define sysctl_exec_name1(state, error_callback, data) NULL
  72 #define sysctl_exec_name2(state, error_callback, data) NULL
  73
  74 #else /* defined (HAVE_KERN_PROC_ARGS) || |defined (HAVE_KERN_PROC) */
  75
  76 static char *
  77 sysctl_exec_name (struct backtrace_state *state,
  78                   int mib0, int mib1, int mib2, int mib3,
  79                   backtrace_error_callback error_callback, void *data)
  80 {
  81   int mib[4];
  82   size_t len;
  83   char *name;
  84   size_t rlen;
  85
  86   mib[0] = mib0;
  87   mib[1] = mib1;
  88   mib[2] = mib2;
  89   mib[3] = mib3;
  90
  91   if (sysctl (mib, 4, NULL, &len, NULL, 0) < 0)
  92     return NULL;
  93   name = (char *) backtrace_alloc (state, len, error_callback, data);
  94   if (name == NULL)
  95     return NULL;
  96   rlen = len;
  97   if (sysctl (mib, 4, name, &rlen, NULL, 0) < 0)
  98     {
  99       backtrace_free (state, name, len, error_callback, data);
 100       return NULL;
 101     }
 102   return name;
 103 }
 104
 105 #ifdef HAVE_KERN_PROC_ARGS
 106
 107 static char *
 108 sysctl_exec_name1 (struct backtrace_state *state,
 109                    backtrace_error_callback error_callback, void *data)
 110 {
 111   /* This variant is used on NetBSD.  */
 112   return sysctl_exec_name (state, CTL_KERN, KERN_PROC_ARGS, -1,
 113                            KERN_PROC_PATHNAME, error_callback, data);
 114 }
 115
 116 #else
 117
 118 #define sysctl_exec_name1(state, error_callback, data) NULL
 119
 120 #endif
 121
 122 #ifdef HAVE_KERN_PROC
 123
 124 static char *
 125 sysctl_exec_name2 (struct backtrace_state *state,
 126                    backtrace_error_callback error_callback, void *data)
 127 {
 128   /* This variant is used on FreeBSD.  */
 129   return sysctl_exec_name (state, CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1,
 130                            error_callback, data);
 131 }
 132
 133 #else
 134
 135 #define sysctl_exec_name2(state, error_callback, data) NULL
 136
 137 #endif
 138
 139 #endif /* defined (HAVE_KERN_PROC_ARGS) || |defined (HAVE_KERN_PROC) */
 140
 141 #ifdef HAVE_MACH_O_DYLD_H
 142
 143 static char *
 144 macho_get_executable_path (struct backtrace_state *state,
 145                            backtrace_error_callback error_callback, void *data)
 146 {
 147   uint32_t len;
 148   char *name;
 149
 150   len = 0;
 151   if (_NSGetExecutablePath (NULL, &len) == 0)
 152     return NULL;
 153   name = (char *) backtrace_alloc (state, len, error_callback, data);
 154   if (name == NULL)
 155     return NULL;
 156   if (_NSGetExecutablePath (name, &len) != 0)
 157     {
 158       backtrace_free (state, name, len, error_callback, data);
 159       return NULL;
 160     }
 161   return name;
 162 }
 163
 164 #else /* !defined (HAVE_MACH_O_DYLD_H) */
 165
 166 #define macho_get_executable_path(state, error_callback, data) NULL
 167
 168 #endif /* !defined (HAVE_MACH_O_DYLD_H) */
 169
 170 #if HAVE_DECL__PGMPTR
 171
 172 #define windows_executable_filename() _pgmptr
 173
 174 #else /* !HAVE_DECL__PGMPTR */
 175
 176 #define windows_executable_filename() NULL
 177
 178 #endif /* !HAVE_DECL__PGMPTR */
 179
 180 #ifdef HAVE_WINDOWS_H
 181
 182 #define FILENAME_BUF_SIZE (MAX_PATH)
 183
 184 static char *
 185 windows_get_executable_path (char *buf, backtrace_error_callback error_callback,
 186                              void *data)
 187 {
 188   size_t got;
 189   int error;
 190
 191   got = GetModuleFileNameA (NULL, buf, FILENAME_BUF_SIZE - 1);
 192   error = GetLastError ();
 193   if (got == 0
 194       || (got == FILENAME_BUF_SIZE - 1 && error == ERROR_INSUFFICIENT_BUFFER))
 195     {
 196       error_callback (data,
 197                       "could not get the filename of the current executable",
 198                       error);
 199       return NULL;
 200     }
 201   return buf;
 202 }
 203
 204 #else /* !defined (HAVE_WINDOWS_H) */
 205
 206 #define windows_get_executable_path(buf, error_callback, data) NULL
 207 #define FILENAME_BUF_SIZE 64
 208
 209 #endif /* !defined (HAVE_WINDOWS_H) */
 210
 211 /* Initialize the fileline information from the executable.  Returns 1
 212    on success, 0 on failure.  */
 213
 214 static int
 215 fileline_initialize (struct backtrace_state *state,
 216                      backtrace_error_callback error_callback, void *data)
 217 {
 218   int failed;
 219   fileline fileline_fn;
 220   int pass;
 221   int called_error_callback;
 222   int descriptor;
 223   const char *filename;
 224   char buf[FILENAME_BUF_SIZE];
 225
 226   if (!state->threaded)
 227     failed = state->fileline_initialization_failed;
 228   else
 229     failed = backtrace_atomic_load_int (&state->fileline_initialization_failed);
 230
 231   if (failed)
 232     {
 233       error_callback (data, "failed to read executable information", -1);
 234       return 0;
 235     }
 236
 237   if (!state->threaded)
 238     fileline_fn = state->fileline_fn;
 239   else
 240     fileline_fn = backtrace_atomic_load_pointer (&state->fileline_fn);
 241   if (fileline_fn != NULL)
 242     return 1;
 243
 244   /* We have not initialized the information.  Do it now.  */
 245
 246   descriptor = -1;
 247   called_error_callback = 0;
 248   for (pass = 0; pass < 10; ++pass)
 249     {
 250       int does_not_exist;
 251
 252       switch (pass)
 253         {
 254         case 0:
 255           filename = state->filename;
 256           break;
 257         case 1:
 258           filename = getexecname ();
 259           break;
 260         case 2:
 261           /* Test this before /proc/self/exe, as the latter exists but points
 262              to the wine binary (and thus doesn't work).  */
 263           filename = windows_executable_filename ();
 264           break;
 265         case 3:
 266           filename = "/proc/self/exe";
 267           break;
 268         case 4:
 269           filename = "/proc/curproc/file";
 270           break;
 271         case 5:
 272           snprintf (buf, sizeof (buf), "/proc/%ld/object/a.out",
 273                     (long) getpid ());
 274           filename = buf;
 275           break;
 276         case 6:
 277           filename = sysctl_exec_name1 (state, error_callback, data);
 278           break;
 279         case 7:
 280           filename = sysctl_exec_name2 (state, error_callback, data);
 281           break;
 282         case 8:
 283           filename = macho_get_executable_path (state, error_callback, data);
 284           break;
 285         case 9:
 286           filename = windows_get_executable_path (buf, error_callback, data);
 287           break;
 288         default:
 289           abort ();
 290         }
 291
 292       if (filename == NULL)
 293         continue;
 294
 295       descriptor = backtrace_open (filename, error_callback, data,
 296                                    &does_not_exist);
 297       if (descriptor < 0 && !does_not_exist)
 298         {
 299           called_error_callback = 1;
 300           break;
 301         }
 302       if (descriptor >= 0)
 303         break;
 304     }
 305
 306   if (descriptor < 0)
 307     {
 308       if (!called_error_callback)
 309         {
 310           if (state->filename != NULL)
 311             error_callback (data, state->filename, ENOENT);
 312           else
 313             error_callback (data,
 314                             "libbacktrace could not find executable to open",
 315                             0);
 316         }
 317       failed = 1;
 318     }
 319
 320   if (!failed)
 321     {
 322       if (!backtrace_initialize (state, filename, descriptor, error_callback,
 323                                  data, &fileline_fn))
 324         failed = 1;
 325     }
 326
 327   if (failed)
 328     {
 329       if (!state->threaded)
 330         state->fileline_initialization_failed = 1;
 331       else
 332         backtrace_atomic_store_int (&state->fileline_initialization_failed, 1);
 333       return 0;
 334     }
 335
 336   if (!state->threaded)
 337     state->fileline_fn = fileline_fn;
 338   else
 339     {
 340       backtrace_atomic_store_pointer (&state->fileline_fn, fileline_fn);
 341
 342       /* Note that if two threads initialize at once, one of the data
 343          sets may be leaked.  */
 344     }
 345
 346   return 1;
 347 }
 348
 349 /* Given a PC, find the file name, line number, and function name.  */
 350
 351 int
 352 backtrace_pcinfo (struct backtrace_state *state, uintptr_t pc,
 353                   backtrace_full_callback callback,
 354                   backtrace_error_callback error_callback, void *data)
 355 {
 356   if (!fileline_initialize (state, error_callback, data))
 357     return 0;
 358
 359   if (state->fileline_initialization_failed)
 360     return 0;
 361
 362   return state->fileline_fn (state, pc, callback, error_callback, data);
 363 }
 364
 365 /* Given a PC, find the symbol for it, and its value.  */
 366
 367 int
 368 backtrace_syminfo (struct backtrace_state *state, uintptr_t pc,
 369                    backtrace_syminfo_callback callback,
 370                    backtrace_error_callback error_callback, void *data)
 371 {
 372   if (!fileline_initialize (state, error_callback, data))
 373     return 0;
 374
 375   if (state->fileline_initialization_failed)
 376     return 0;
 377
 378   state->syminfo_fn (state, pc, callback, error_callback, data);
 379   return 1;
 380 }
 381
 382 /* A backtrace_syminfo_callback that can call into a
 383    backtrace_full_callback, used when we have a symbol table but no
 384    debug info.  */
 385
 386 void
 387 backtrace_syminfo_to_full_callback (void *data, uintptr_t pc,
 388                                     const char *symname,
 389                                     uintptr_t symval ATTRIBUTE_UNUSED,
 390                                     uintptr_t symsize ATTRIBUTE_UNUSED)
 391 {
 392   struct backtrace_call_full *bdata = (struct backtrace_call_full *) data;
 393
 394   bdata->ret = bdata->full_callback (bdata->full_data, pc, NULL, 0, symname);
 395 }
 396
 397 /* An error callback that corresponds to
 398    backtrace_syminfo_to_full_callback.  */
 399
 400 void
 401 backtrace_syminfo_to_full_error_callback (void *data, const char *msg,
 402                                           int errnum)
 403 {
 404   struct backtrace_call_full *bdata = (struct backtrace_call_full *) data;
 405
 406   bdata->full_error_callback (bdata->full_data, msg, errnum);
 407 }