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