glib/gbacktrace.c

   1 /* GLIB - Library of useful routines for C programming
   2  * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17  * Boston, MA 02111-1307, USA.
  18  */
  19
  20 /*
  21  * Modified by the GLib Team and others 1997-2000.  See the AUTHORS
  22  * file for a list of people on the GLib Team.  See the ChangeLog
  23  * files for a list of changes.  These files are distributed with
  24  * GLib at ftp://ftp.gtk.org/pub/gtk/.
  25  */
  26
  27 /*
  28  * MT safe ; except for g_on_error_stack_trace, but who wants thread safety
  29  * then
  30  */
  31
  32 #include "config.h"
  33 #include "glibconfig.h"
  34
  35 #include <signal.h>
  36 #include <stdarg.h>
  37 #include <stdio.h>
  38 #include <stdlib.h>
  39
  40 #ifdef HAVE_SYS_TIME_H
  41 #include <sys/time.h>
  42 #endif
  43 #include <sys/types.h>
  44
  45 #include <time.h>
  46
  47 #ifdef G_OS_UNIX
  48 #include <unistd.h>
  49 #include <sys/wait.h>
  50 #ifdef HAVE_SYS_SELECT_H
  51 #include <sys/select.h>
  52 #endif /* HAVE_SYS_SELECT_H */
  53 #endif
  54
  55 #include <string.h>
  56
  57 #ifdef G_OS_WIN32
  58 #  define STRICT                /* Strict typing, please */
  59 #  define _WIN32_WINDOWS 0x0401 /* to get IsDebuggerPresent */
  60 #  include <windows.h>
  61 #  undef STRICT
  62 #else
  63 #  include <fcntl.h>
  64 #endif
  65
  66 #include "gbacktrace.h"
  67
  68 #include "gtypes.h"
  69 #include "gmain.h"
  70 #include "gprintfint.h"
  71 #include "gutils.h"
  72
  73
  74 #ifndef NO_FD_SET
  75 #  define SELECT_MASK fd_set
  76 #else
  77 #  if defined(_IBMR2)
  78 #    define SELECT_MASK void
  79 #  else
  80 #    define SELECT_MASK int
  81 #  endif
  82 #endif
  83
  84
  85 #ifndef G_OS_WIN32
  86 static void stack_trace (char **args);
  87 #endif
  88
  89 /* People want to hit this from their debugger... */
  90 GLIB_AVAILABLE_IN_ALL volatile gboolean glib_on_error_halt;
  91 volatile gboolean glib_on_error_halt = TRUE;
  92
  93 /**
  94  * g_on_error_query:
  95  * @prg_name: the program name, needed by <command>gdb</command>
  96  *     for the [S]tack trace option. If @prg_name is %NULL, g_get_prgname()
  97  *     is called to get the program name (which will work correctly if
  98  *     gdk_init() or gtk_init() has been called)
  99  *
 100  * Prompts the user with
 101  * <computeroutput>[E]xit, [H]alt, show [S]tack trace or [P]roceed</computeroutput>.
 102  * This function is intended to be used for debugging use only.
 103  * The following example shows how it can be used together with
 104  * the g_log() functions.
 105  *
 106  * |[
 107  * &num;include &lt;glib.h&gt;
 108  *
 109  * static void
 110  * log_handler (const gchar   *log_domain,
 111  *              GLogLevelFlags log_level,
 112  *              const gchar   *message,
 113  *              gpointer       user_data)
 114  * {
 115  *   g_log_default_handler (log_domain, log_level, message, user_data);
 116  *
 117  *   g_on_error_query (MY_PROGRAM_NAME);
 118  * }
 119  *
 120  * int
 121  * main (int argc, char *argv[])
 122  * {
 123  *   g_log_set_handler (MY_LOG_DOMAIN,
 124  *                      G_LOG_LEVEL_WARNING |
 125  *                      G_LOG_LEVEL_ERROR |
 126  *                      G_LOG_LEVEL_CRITICAL,
 127  *                      log_handler,
 128  *                      NULL);
 129  *   /&ast; ... &ast;/
 130  * ]|
 131  *
 132  * If [E]xit is selected, the application terminates with a call
 133  * to <literal>_exit(0)</literal>.
 134  *
 135  * If [S]tack trace is selected, g_on_error_stack_trace() is called.
 136  * This invokes <command>gdb</command>, which attaches to the current
 137  * process and shows a stack trace. The prompt is then shown again.
 138  *
 139  * If [P]roceed is selected, the function returns.
 140  *
 141  * This function may cause different actions on non-UNIX platforms.
 142  */
 143 void
 144 g_on_error_query (const gchar *prg_name)
 145 {
 146 #ifndef G_OS_WIN32
 147   static const gchar * const query1 = "[E]xit, [H]alt";
 148   static const gchar * const query2 = ", show [S]tack trace";
 149   static const gchar * const query3 = " or [P]roceed";
 150   gchar buf[16];
 151
 152   if (!prg_name)
 153     prg_name = g_get_prgname ();
 154
 155  retry:
 156
 157   if (prg_name)
 158     _g_fprintf (stdout,
 159                 "%s (pid:%u): %s%s%s: ",
 160                 prg_name,
 161                 (guint) getpid (),
 162                 query1,
 163                 query2,
 164                 query3);
 165   else
 166     _g_fprintf (stdout,
 167                 "(process:%u): %s%s: ",
 168                 (guint) getpid (),
 169                 query1,
 170                 query3);
 171   fflush (stdout);
 172
 173   if (isatty(0) && isatty(1))
 174     fgets (buf, 8, stdin);
 175   else
 176     strcpy (buf, "E\n");
 177
 178   if ((buf[0] == 'E' || buf[0] == 'e')
 179       && buf[1] == '\n')
 180     _exit (0);
 181   else if ((buf[0] == 'P' || buf[0] == 'p')
 182            && buf[1] == '\n')
 183     return;
 184   else if (prg_name
 185            && (buf[0] == 'S' || buf[0] == 's')
 186            && buf[1] == '\n')
 187     {
 188       g_on_error_stack_trace (prg_name);
 189       goto retry;
 190     }
 191   else if ((buf[0] == 'H' || buf[0] == 'h')
 192            && buf[1] == '\n')
 193     {
 194       while (glib_on_error_halt)
 195         ;
 196       glib_on_error_halt = TRUE;
 197       return;
 198     }
 199   else
 200     goto retry;
 201 #else
 202   if (!prg_name)
 203     prg_name = g_get_prgname ();
 204
 205   MessageBox (NULL, "g_on_error_query called, program terminating",
 206               (prg_name && *prg_name) ? prg_name : NULL,
 207               MB_OK|MB_ICONERROR);
 208   _exit(0);
 209 #endif
 210 }
 211
 212 /**
 213  * g_on_error_stack_trace:
 214  * @prg_name: the program name, needed by <command>gdb</command>
 215  *     for the [S]tack trace option.
 216  *
 217  * Invokes <command>gdb</command>, which attaches to the current
 218  * process and shows a stack trace. Called by g_on_error_query()
 219  * when the [S]tack trace option is selected. You can get the current
 220  * process's "program name" with g_get_prgname(), assuming that you
 221  * have called gtk_init() or gdk_init().
 222  *
 223  * This function may cause different actions on non-UNIX platforms.
 224  */
 225 void
 226 g_on_error_stack_trace (const gchar *prg_name)
 227 {
 228 #if defined(G_OS_UNIX)
 229   pid_t pid;
 230   gchar buf[16];
 231   gchar *args[4] = { "gdb", NULL, NULL, NULL };
 232   int status;
 233
 234   if (!prg_name)
 235     return;
 236
 237   _g_sprintf (buf, "%u", (guint) getpid ());
 238
 239   args[1] = (gchar*) prg_name;
 240   args[2] = buf;
 241
 242   pid = fork ();
 243   if (pid == 0)
 244     {
 245       stack_trace (args);
 246       _exit (0);
 247     }
 248   else if (pid == (pid_t) -1)
 249     {
 250       perror ("unable to fork gdb");
 251       return;
 252     }
 253
 254   waitpid (pid, &status, 0);
 255 #else
 256   if (IsDebuggerPresent ())
 257     G_BREAKPOINT ();
 258   else
 259     abort ();
 260 #endif
 261 }
 262
 263 #ifndef G_OS_WIN32
 264
 265 static gboolean stack_trace_done = FALSE;
 266
 267 static void
 268 stack_trace_sigchld (int signum)
 269 {
 270   stack_trace_done = TRUE;
 271 }
 272
 273 static void
 274 stack_trace (char **args)
 275 {
 276   pid_t pid;
 277   int in_fd[2];
 278   int out_fd[2];
 279   SELECT_MASK fdset;
 280   SELECT_MASK readset;
 281   struct timeval tv;
 282   int sel, idx, state;
 283   char buffer[256];
 284   char c;
 285
 286   stack_trace_done = FALSE;
 287   signal (SIGCHLD, stack_trace_sigchld);
 288
 289   if ((pipe (in_fd) == -1) || (pipe (out_fd) == -1))
 290     {
 291       perror ("unable to open pipe");
 292       _exit (0);
 293     }
 294
 295   pid = fork ();
 296   if (pid == 0)
 297     {
 298       /* Save stderr for printing failure below */
 299       int old_err = dup (2);
 300       fcntl (old_err, F_SETFD, fcntl (old_err, F_GETFD) | FD_CLOEXEC);
 301
 302       close (0); dup (in_fd[0]);   /* set the stdin to the in pipe */
 303       close (1); dup (out_fd[1]);  /* set the stdout to the out pipe */
 304       close (2); dup (out_fd[1]);  /* set the stderr to the out pipe */
 305
 306       execvp (args[0], args);      /* exec gdb */
 307
 308       /* Print failure to original stderr */
 309       close (2); dup (old_err);
 310       perror ("exec gdb failed");
 311       _exit (0);
 312     }
 313   else if (pid == (pid_t) -1)
 314     {
 315       perror ("unable to fork");
 316       _exit (0);
 317     }
 318
 319   FD_ZERO (&fdset);
 320   FD_SET (out_fd[0], &fdset);
 321
 322   write (in_fd[1], "backtrace\n", 10);
 323   write (in_fd[1], "p x = 0\n", 8);
 324   write (in_fd[1], "quit\n", 5);
 325
 326   idx = 0;
 327   state = 0;
 328
 329   while (1)
 330     {
 331       readset = fdset;
 332       tv.tv_sec = 1;
 333       tv.tv_usec = 0;
 334
 335       sel = select (FD_SETSIZE, &readset, NULL, NULL, &tv);
 336       if (sel == -1)
 337         break;
 338
 339       if ((sel > 0) && (FD_ISSET (out_fd[0], &readset)))
 340         {
 341           if (read (out_fd[0], &c, 1))
 342             {
 343               switch (state)
 344                 {
 345                 case 0:
 346                   if (c == '#')
 347                     {
 348                       state = 1;
 349                       idx = 0;
 350                       buffer[idx++] = c;
 351                     }
 352                   break;
 353                 case 1:
 354                   buffer[idx++] = c;
 355                   if ((c == '\n') || (c == '\r'))
 356                     {
 357                       buffer[idx] = 0;
 358                       _g_fprintf (stdout, "%s", buffer);
 359                       state = 0;
 360                       idx = 0;
 361                     }
 362                   break;
 363                 default:
 364                   break;
 365                 }
 366             }
 367         }
 368       else if (stack_trace_done)
 369         break;
 370     }
 371
 372   close (in_fd[0]);
 373   close (in_fd[1]);
 374   close (out_fd[0]);
 375   close (out_fd[1]);
 376   _exit (0);
 377 }
 378
 379 #endif /* !G_OS_WIN32 */