gdb/break-catch-sig.c

   1 /* Everything about signal catchpoints, for GDB.
   2
   3    Copyright (C) 2011-2014 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include "arch-utils.h"
  22 #include <ctype.h>
  23 #include "breakpoint.h"
  24 #include "gdbcmd.h"
  25 #include "inferior.h"
  26 #include "annotate.h"
  27 #include "valprint.h"
  28 #include "cli/cli-utils.h"
  29 #include "completer.h"
  30 #include "gdb_obstack.h"
  31
  32 #define INTERNAL_SIGNAL(x) ((x) == GDB_SIGNAL_TRAP || (x) == GDB_SIGNAL_INT)
  33
  34 typedef enum gdb_signal gdb_signal_type;
  35
  36 DEF_VEC_I (gdb_signal_type);
  37
  38 /* An instance of this type is used to represent a signal catchpoint.
  39    It includes a "struct breakpoint" as a kind of base class; users
  40    downcast to "struct breakpoint *" when needed.  A breakpoint is
  41    really of this type iff its ops pointer points to
  42    SIGNAL_CATCHPOINT_OPS.  */
  43
  44 struct signal_catchpoint
  45 {
  46   /* The base class.  */
  47
  48   struct breakpoint base;
  49
  50   /* Signal numbers used for the 'catch signal' feature.  If no signal
  51      has been specified for filtering, its value is NULL.  Otherwise,
  52      it holds a list of all signals to be caught.  */
  53
  54   VEC (gdb_signal_type) *signals_to_be_caught;
  55
  56   /* If SIGNALS_TO_BE_CAUGHT is NULL, then all "ordinary" signals are
  57      caught.  If CATCH_ALL is non-zero, then internal signals are
  58      caught as well.  If SIGNALS_TO_BE_CAUGHT is non-NULL, then this
  59      field is ignored.  */
  60
  61   int catch_all;
  62 };
  63
  64 /* The breakpoint_ops structure to be used in signal catchpoints.  */
  65
  66 static struct breakpoint_ops signal_catchpoint_ops;
  67
  68 /* Count of each signal.  */
  69
  70 static unsigned int *signal_catch_counts;
  71
  72 \f
  73
  74 /* A convenience wrapper for gdb_signal_to_name that returns the
  75    integer value if the name is not known.  */
  76
  77 static const char *
  78 signal_to_name_or_int (enum gdb_signal sig)
  79 {
  80   const char *result = gdb_signal_to_name (sig);
  81
  82   if (strcmp (result, "?") == 0)
  83     result = plongest (sig);
  84
  85   return result;
  86 }
  87
  88 \f
  89
  90 /* Implement the "dtor" breakpoint_ops method for signal
  91    catchpoints.  */
  92
  93 static void
  94 signal_catchpoint_dtor (struct breakpoint *b)
  95 {
  96   struct signal_catchpoint *c = (struct signal_catchpoint *) b;
  97
  98   VEC_free (gdb_signal_type, c->signals_to_be_caught);
  99
 100   base_breakpoint_ops.dtor (b);
 101 }
 102
 103 /* Implement the "insert_location" breakpoint_ops method for signal
 104    catchpoints.  */
 105
 106 static int
 107 signal_catchpoint_insert_location (struct bp_location *bl)
 108 {
 109   struct signal_catchpoint *c = (void *) bl->owner;
 110   int i;
 111
 112   if (c->signals_to_be_caught != NULL)
 113     {
 114       gdb_signal_type iter;
 115
 116       for (i = 0;
 117            VEC_iterate (gdb_signal_type, c->signals_to_be_caught, i, iter);
 118            i++)
 119         ++signal_catch_counts[iter];
 120     }
 121   else
 122     {
 123       for (i = 0; i < GDB_SIGNAL_LAST; ++i)
 124         {
 125           if (c->catch_all || !INTERNAL_SIGNAL (i))
 126             ++signal_catch_counts[i];
 127         }
 128     }
 129
 130   signal_catch_update (signal_catch_counts);
 131
 132   return 0;
 133 }
 134
 135 /* Implement the "remove_location" breakpoint_ops method for signal
 136    catchpoints.  */
 137
 138 static int
 139 signal_catchpoint_remove_location (struct bp_location *bl)
 140 {
 141   struct signal_catchpoint *c = (void *) bl->owner;
 142   int i;
 143
 144   if (c->signals_to_be_caught != NULL)
 145     {
 146       gdb_signal_type iter;
 147
 148       for (i = 0;
 149            VEC_iterate (gdb_signal_type, c->signals_to_be_caught, i, iter);
 150            i++)
 151         {
 152           gdb_assert (signal_catch_counts[iter] > 0);
 153           --signal_catch_counts[iter];
 154         }
 155     }
 156   else
 157     {
 158       for (i = 0; i < GDB_SIGNAL_LAST; ++i)
 159         {
 160           if (c->catch_all || !INTERNAL_SIGNAL (i))
 161             {
 162               gdb_assert (signal_catch_counts[i] > 0);
 163               --signal_catch_counts[i];
 164             }
 165         }
 166     }
 167
 168   signal_catch_update (signal_catch_counts);
 169
 170   return 0;
 171 }
 172
 173 /* Implement the "breakpoint_hit" breakpoint_ops method for signal
 174    catchpoints.  */
 175
 176 static int
 177 signal_catchpoint_breakpoint_hit (const struct bp_location *bl,
 178                                   struct address_space *aspace,
 179                                   CORE_ADDR bp_addr,
 180                                   const struct target_waitstatus *ws)
 181 {
 182   const struct signal_catchpoint *c = (void *) bl->owner;
 183   gdb_signal_type signal_number;
 184
 185   if (ws->kind != TARGET_WAITKIND_STOPPED)
 186     return 0;
 187
 188   signal_number = ws->value.sig;
 189
 190   /* If we are catching specific signals in this breakpoint, then we
 191      must guarantee that the called signal is the same signal we are
 192      catching.  */
 193   if (c->signals_to_be_caught)
 194     {
 195       int i;
 196       gdb_signal_type iter;
 197
 198       for (i = 0;
 199            VEC_iterate (gdb_signal_type, c->signals_to_be_caught, i, iter);
 200            i++)
 201         if (signal_number == iter)
 202           return 1;
 203       /* Not the same.  */
 204       gdb_assert (!iter);
 205       return 0;
 206     }
 207   else
 208     return c->catch_all || !INTERNAL_SIGNAL (signal_number);
 209 }
 210
 211 /* Implement the "print_it" breakpoint_ops method for signal
 212    catchpoints.  */
 213
 214 static enum print_stop_action
 215 signal_catchpoint_print_it (bpstat bs)
 216 {
 217   struct breakpoint *b = bs->breakpoint_at;
 218   ptid_t ptid;
 219   struct target_waitstatus last;
 220   const char *signal_name;
 221
 222   get_last_target_status (&ptid, &last);
 223
 224   signal_name = signal_to_name_or_int (last.value.sig);
 225
 226   annotate_catchpoint (b->number);
 227
 228   printf_filtered (_("\nCatchpoint %d (signal %s), "), b->number, signal_name);
 229
 230   return PRINT_SRC_AND_LOC;
 231 }
 232
 233 /* Implement the "print_one" breakpoint_ops method for signal
 234    catchpoints.  */
 235
 236 static void
 237 signal_catchpoint_print_one (struct breakpoint *b,
 238                              struct bp_location **last_loc)
 239 {
 240   struct signal_catchpoint *c = (void *) b;
 241   struct value_print_options opts;
 242   struct ui_out *uiout = current_uiout;
 243
 244   get_user_print_options (&opts);
 245
 246   /* Field 4, the address, is omitted (which makes the columns
 247      not line up too nicely with the headers, but the effect
 248      is relatively readable).  */
 249   if (opts.addressprint)
 250     ui_out_field_skip (uiout, "addr");
 251   annotate_field (5);
 252
 253   if (c->signals_to_be_caught
 254       && VEC_length (gdb_signal_type, c->signals_to_be_caught) > 1)
 255     ui_out_text (uiout, "signals \"");
 256   else
 257     ui_out_text (uiout, "signal \"");
 258
 259   if (c->signals_to_be_caught)
 260     {
 261       int i;
 262       gdb_signal_type iter;
 263       struct obstack text;
 264       struct cleanup *cleanup;
 265
 266       obstack_init (&text);
 267       cleanup = make_cleanup_obstack_free (&text);
 268
 269       for (i = 0;
 270            VEC_iterate (gdb_signal_type, c->signals_to_be_caught, i, iter);
 271            i++)
 272         {
 273           const char *name = signal_to_name_or_int (iter);
 274
 275           if (i > 0)
 276             obstack_grow (&text, " ", 1);
 277           obstack_grow (&text, name, strlen (name));
 278         }
 279       obstack_grow (&text, "", 1);
 280       ui_out_field_string (uiout, "what", obstack_base (&text));
 281       do_cleanups (cleanup);
 282     }
 283   else
 284     ui_out_field_string (uiout, "what",
 285                          c->catch_all ? "<any signal>" : "<standard signals>");
 286   ui_out_text (uiout, "\" ");
 287
 288   if (ui_out_is_mi_like_p (uiout))
 289     ui_out_field_string (uiout, "catch-type", "signal");
 290 }
 291
 292 /* Implement the "print_mention" breakpoint_ops method for signal
 293    catchpoints.  */
 294
 295 static void
 296 signal_catchpoint_print_mention (struct breakpoint *b)
 297 {
 298   struct signal_catchpoint *c = (void *) b;
 299
 300   if (c->signals_to_be_caught)
 301     {
 302       int i;
 303       gdb_signal_type iter;
 304
 305       if (VEC_length (gdb_signal_type, c->signals_to_be_caught) > 1)
 306         printf_filtered (_("Catchpoint %d (signals"), b->number);
 307       else
 308         printf_filtered (_("Catchpoint %d (signal"), b->number);
 309
 310       for (i = 0;
 311            VEC_iterate (gdb_signal_type, c->signals_to_be_caught, i, iter);
 312            i++)
 313         {
 314           const char *name = signal_to_name_or_int (iter);
 315
 316           printf_filtered (" %s", name);
 317         }
 318       printf_filtered (")");
 319     }
 320   else if (c->catch_all)
 321     printf_filtered (_("Catchpoint %d (any signal)"), b->number);
 322   else
 323     printf_filtered (_("Catchpoint %d (standard signals)"), b->number);
 324 }
 325
 326 /* Implement the "print_recreate" breakpoint_ops method for signal
 327    catchpoints.  */
 328
 329 static void
 330 signal_catchpoint_print_recreate (struct breakpoint *b, struct ui_file *fp)
 331 {
 332   struct signal_catchpoint *c = (void *) b;
 333
 334   fprintf_unfiltered (fp, "catch signal");
 335
 336   if (c->signals_to_be_caught)
 337     {
 338       int i;
 339       gdb_signal_type iter;
 340
 341       for (i = 0;
 342            VEC_iterate (gdb_signal_type, c->signals_to_be_caught, i, iter);
 343            i++)
 344         fprintf_unfiltered (fp, " %s", signal_to_name_or_int (iter));
 345     }
 346   else if (c->catch_all)
 347     fprintf_unfiltered (fp, " all");
 348 }
 349
 350 /* Implement the "explains_signal" breakpoint_ops method for signal
 351    catchpoints.  */
 352
 353 static int
 354 signal_catchpoint_explains_signal (struct breakpoint *b, enum gdb_signal sig)
 355 {
 356   return 1;
 357 }
 358
 359 /* Create a new signal catchpoint.  TEMPFLAG is true if this should be
 360    a temporary catchpoint.  FILTER is the list of signals to catch; it
 361    can be NULL, meaning all signals.  CATCH_ALL is a flag indicating
 362    whether signals used internally by gdb should be caught; it is only
 363    valid if FILTER is NULL.  If FILTER is NULL and CATCH_ALL is zero,
 364    then internal signals like SIGTRAP are not caught.  */
 365
 366 static void
 367 create_signal_catchpoint (int tempflag, VEC (gdb_signal_type) *filter,
 368                           int catch_all)
 369 {
 370   struct signal_catchpoint *c;
 371   struct gdbarch *gdbarch = get_current_arch ();
 372
 373   c = XNEW (struct signal_catchpoint);
 374   init_catchpoint (&c->base, gdbarch, tempflag, NULL, &signal_catchpoint_ops);
 375   c->signals_to_be_caught = filter;
 376   c->catch_all = catch_all;
 377
 378   install_breakpoint (0, &c->base, 1);
 379 }
 380
 381
 382 /* Splits the argument using space as delimiter.  Returns an xmalloc'd
 383    filter list, or NULL if no filtering is required.  */
 384
 385 static VEC (gdb_signal_type) *
 386 catch_signal_split_args (char *arg, int *catch_all)
 387 {
 388   VEC (gdb_signal_type) *result = NULL;
 389   struct cleanup *cleanup = make_cleanup (VEC_cleanup (gdb_signal_type),
 390                                           &result);
 391   int first = 1;
 392
 393   while (*arg != '\0')
 394     {
 395       int num;
 396       gdb_signal_type signal_number;
 397       char *one_arg, *endptr;
 398       struct cleanup *inner_cleanup;
 399
 400       one_arg = extract_arg (&arg);
 401       if (one_arg == NULL)
 402         break;
 403       inner_cleanup = make_cleanup (xfree, one_arg);
 404
 405       /* Check for the special flag "all".  */
 406       if (strcmp (one_arg, "all") == 0)
 407         {
 408           arg = skip_spaces (arg);
 409           if (*arg != '\0' || !first)
 410             error (_("'all' cannot be caught with other signals"));
 411           *catch_all = 1;
 412           gdb_assert (result == NULL);
 413           do_cleanups (inner_cleanup);
 414           discard_cleanups (cleanup);
 415           return NULL;
 416         }
 417
 418       first = 0;
 419
 420       /* Check if the user provided a signal name or a number.  */
 421       num = (int) strtol (one_arg, &endptr, 0);
 422       if (*endptr == '\0')
 423         signal_number = gdb_signal_from_command (num);
 424       else
 425         {
 426           signal_number = gdb_signal_from_name (one_arg);
 427           if (signal_number == GDB_SIGNAL_UNKNOWN)
 428             error (_("Unknown signal name '%s'."), one_arg);
 429         }
 430
 431       VEC_safe_push (gdb_signal_type, result, signal_number);
 432       do_cleanups (inner_cleanup);
 433     }
 434
 435   discard_cleanups (cleanup);
 436   return result;
 437 }
 438
 439 /* Implement the "catch signal" command.  */
 440
 441 static void
 442 catch_signal_command (char *arg, int from_tty,
 443                       struct cmd_list_element *command)
 444 {
 445   int tempflag, catch_all = 0;
 446   VEC (gdb_signal_type) *filter;
 447
 448   tempflag = get_cmd_context (command) == CATCH_TEMPORARY;
 449
 450   arg = skip_spaces (arg);
 451
 452   /* The allowed syntax is:
 453      catch signal
 454      catch signal <name | number> [<name | number> ... <name | number>]
 455
 456      Let's check if there's a signal name.  */
 457
 458   if (arg != NULL)
 459     filter = catch_signal_split_args (arg, &catch_all);
 460   else
 461     filter = NULL;
 462
 463   create_signal_catchpoint (tempflag, filter, catch_all);
 464 }
 465
 466 static void
 467 initialize_signal_catchpoint_ops (void)
 468 {
 469   struct breakpoint_ops *ops;
 470
 471   initialize_breakpoint_ops ();
 472
 473   ops = &signal_catchpoint_ops;
 474   *ops = base_breakpoint_ops;
 475   ops->dtor = signal_catchpoint_dtor;
 476   ops->insert_location = signal_catchpoint_insert_location;
 477   ops->remove_location = signal_catchpoint_remove_location;
 478   ops->breakpoint_hit = signal_catchpoint_breakpoint_hit;
 479   ops->print_it = signal_catchpoint_print_it;
 480   ops->print_one = signal_catchpoint_print_one;
 481   ops->print_mention = signal_catchpoint_print_mention;
 482   ops->print_recreate = signal_catchpoint_print_recreate;
 483   ops->explains_signal = signal_catchpoint_explains_signal;
 484 }
 485
 486 initialize_file_ftype _initialize_break_catch_sig;
 487
 488 void
 489 _initialize_break_catch_sig (void)
 490 {
 491   initialize_signal_catchpoint_ops ();
 492
 493   signal_catch_counts = XCNEWVEC (unsigned int, GDB_SIGNAL_LAST);
 494
 495   add_catch_command ("signal", _("\
 496 Catch signals by their names and/or numbers.\n\
 497 Usage: catch signal [[NAME|NUMBER] [NAME|NUMBER]...|all]\n\
 498 Arguments say which signals to catch.  If no arguments\n\
 499 are given, every \"normal\" signal will be caught.\n\
 500 The argument \"all\" means to also catch signals used by GDB.\n\
 501 Arguments, if given, should be one or more signal names\n\
 502 (if your system supports that), or signal numbers."),
 503                      catch_signal_command,
 504                      signal_completer,
 505                      CATCH_PERMANENT,
 506                      CATCH_TEMPORARY);
 507 }