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 "infrun.h"
  27 #include "annotate.h"
  28 #include "valprint.h"
  29 #include "cli/cli-utils.h"
  30 #include "completer.h"
  31 #include "gdb_obstack.h"
  32
  33 #define INTERNAL_SIGNAL(x) ((x) == GDB_SIGNAL_TRAP || (x) == GDB_SIGNAL_INT)
  34
  35 typedef enum gdb_signal gdb_signal_type;
  36
  37 DEF_VEC_I (gdb_signal_type);
  38
  39 /* An instance of this type is used to represent a signal catchpoint.
  40    It includes a "struct breakpoint" as a kind of base class; users
  41    downcast to "struct breakpoint *" when needed.  A breakpoint is
  42    really of this type iff its ops pointer points to
  43    SIGNAL_CATCHPOINT_OPS.  */
  44
  45 struct signal_catchpoint
  46 {
  47   /* The base class.  */
  48
  49   struct breakpoint base;
  50
  51   /* Signal numbers used for the 'catch signal' feature.  If no signal
  52      has been specified for filtering, its value is NULL.  Otherwise,
  53      it holds a list of all signals to be caught.  */
  54
  55   VEC (gdb_signal_type) *signals_to_be_caught;
  56
  57   /* If SIGNALS_TO_BE_CAUGHT is NULL, then all "ordinary" signals are
  58      caught.  If CATCH_ALL is non-zero, then internal signals are
  59      caught as well.  If SIGNALS_TO_BE_CAUGHT is non-NULL, then this
  60      field is ignored.  */
  61
  62   int catch_all;
  63 };
  64
  65 /* The breakpoint_ops structure to be used in signal catchpoints.  */
  66
  67 static struct breakpoint_ops signal_catchpoint_ops;
  68
  69 /* Count of each signal.  */
  70
  71 static unsigned int *signal_catch_counts;
  72
  73 \f
  74
  75 /* A convenience wrapper for gdb_signal_to_name that returns the
  76    integer value if the name is not known.  */
  77
  78 static const char *
  79 signal_to_name_or_int (enum gdb_signal sig)
  80 {
  81   const char *result = gdb_signal_to_name (sig);
  82
  83   if (strcmp (result, "?") == 0)
  84     result = plongest (sig);
  85
  86   return result;
  87 }
  88
  89 \f
  90
  91 /* Implement the "dtor" breakpoint_ops method for signal
  92    catchpoints.  */
  93
  94 static void
  95 signal_catchpoint_dtor (struct breakpoint *b)
  96 {
  97   struct signal_catchpoint *c = (struct signal_catchpoint *) b;
  98
  99   VEC_free (gdb_signal_type, c->signals_to_be_caught);
 100
 101   base_breakpoint_ops.dtor (b);
 102 }
 103
 104 /* Implement the "insert_location" breakpoint_ops method for signal
 105    catchpoints.  */
 106
 107 static int
 108 signal_catchpoint_insert_location (struct bp_location *bl)
 109 {
 110   struct signal_catchpoint *c = (void *) bl->owner;
 111   int i;
 112
 113   if (c->signals_to_be_caught != NULL)
 114     {
 115       gdb_signal_type iter;
 116
 117       for (i = 0;
 118            VEC_iterate (gdb_signal_type, c->signals_to_be_caught, i, iter);
 119            i++)
 120         ++signal_catch_counts[iter];
 121     }
 122   else
 123     {
 124       for (i = 0; i < GDB_SIGNAL_LAST; ++i)
 125         {
 126           if (c->catch_all || !INTERNAL_SIGNAL (i))
 127             ++signal_catch_counts[i];
 128         }
 129     }
 130
 131   signal_catch_update (signal_catch_counts);
 132
 133   return 0;
 134 }
 135
 136 /* Implement the "remove_location" breakpoint_ops method for signal
 137    catchpoints.  */
 138
 139 static int
 140 signal_catchpoint_remove_location (struct bp_location *bl)
 141 {
 142   struct signal_catchpoint *c = (void *) bl->owner;
 143   int i;
 144
 145   if (c->signals_to_be_caught != NULL)
 146     {
 147       gdb_signal_type iter;
 148
 149       for (i = 0;
 150            VEC_iterate (gdb_signal_type, c->signals_to_be_caught, i, iter);
 151            i++)
 152         {
 153           gdb_assert (signal_catch_counts[iter] > 0);
 154           --signal_catch_counts[iter];
 155         }
 156     }
 157   else
 158     {
 159       for (i = 0; i < GDB_SIGNAL_LAST; ++i)
 160         {
 161           if (c->catch_all || !INTERNAL_SIGNAL (i))
 162             {
 163               gdb_assert (signal_catch_counts[i] > 0);
 164               --signal_catch_counts[i];
 165             }
 166         }
 167     }
 168
 169   signal_catch_update (signal_catch_counts);
 170
 171   return 0;
 172 }
 173
 174 /* Implement the "breakpoint_hit" breakpoint_ops method for signal
 175    catchpoints.  */
 176
 177 static int
 178 signal_catchpoint_breakpoint_hit (const struct bp_location *bl,
 179                                   struct address_space *aspace,
 180                                   CORE_ADDR bp_addr,
 181                                   const struct target_waitstatus *ws)
 182 {
 183   const struct signal_catchpoint *c = (void *) bl->owner;
 184   gdb_signal_type signal_number;
 185
 186   if (ws->kind != TARGET_WAITKIND_STOPPED)
 187     return 0;
 188
 189   signal_number = ws->value.sig;
 190
 191   /* If we are catching specific signals in this breakpoint, then we
 192      must guarantee that the called signal is the same signal we are
 193      catching.  */
 194   if (c->signals_to_be_caught)
 195     {
 196       int i;
 197       gdb_signal_type iter;
 198
 199       for (i = 0;
 200            VEC_iterate (gdb_signal_type, c->signals_to_be_caught, i, iter);
 201            i++)
 202         if (signal_number == iter)
 203           return 1;
 204       /* Not the same.  */
 205       gdb_assert (!iter);
 206       return 0;
 207     }
 208   else
 209     return c->catch_all || !INTERNAL_SIGNAL (signal_number);
 210 }
 211
 212 /* Implement the "print_it" breakpoint_ops method for signal
 213    catchpoints.  */
 214
 215 static enum print_stop_action
 216 signal_catchpoint_print_it (bpstat bs)
 217 {
 218   struct breakpoint *b = bs->breakpoint_at;
 219   ptid_t ptid;
 220   struct target_waitstatus last;
 221   const char *signal_name;
 222
 223   get_last_target_status (&ptid, &last);
 224
 225   signal_name = signal_to_name_or_int (last.value.sig);
 226
 227   annotate_catchpoint (b->number);
 228
 229   printf_filtered (_("\nCatchpoint %d (signal %s), "), b->number, signal_name);
 230
 231   return PRINT_SRC_AND_LOC;
 232 }
 233
 234 /* Implement the "print_one" breakpoint_ops method for signal
 235    catchpoints.  */
 236
 237 static void
 238 signal_catchpoint_print_one (struct breakpoint *b,
 239                              struct bp_location **last_loc)
 240 {
 241   struct signal_catchpoint *c = (void *) b;
 242   struct value_print_options opts;
 243   struct ui_out *uiout = current_uiout;
 244
 245   get_user_print_options (&opts);
 246
 247   /* Field 4, the address, is omitted (which makes the columns
 248      not line up too nicely with the headers, but the effect
 249      is relatively readable).  */
 250   if (opts.addressprint)
 251     ui_out_field_skip (uiout, "addr");
 252   annotate_field (5);
 253
 254   if (c->signals_to_be_caught
 255       && VEC_length (gdb_signal_type, c->signals_to_be_caught) > 1)
 256     ui_out_text (uiout, "signals \"");
 257   else
 258     ui_out_text (uiout, "signal \"");
 259
 260   if (c->signals_to_be_caught)
 261     {
 262       int i;
 263       gdb_signal_type iter;
 264       struct obstack text;
 265       struct cleanup *cleanup;
 266
 267       obstack_init (&text);
 268       cleanup = make_cleanup_obstack_free (&text);
 269
 270       for (i = 0;
 271            VEC_iterate (gdb_signal_type, c->signals_to_be_caught, i, iter);
 272            i++)
 273         {
 274           const char *name = signal_to_name_or_int (iter);
 275
 276           if (i > 0)
 277             obstack_grow (&text, " ", 1);
 278           obstack_grow (&text, name, strlen (name));
 279         }
 280       obstack_grow (&text, "", 1);
 281       ui_out_field_string (uiout, "what", obstack_base (&text));
 282       do_cleanups (cleanup);
 283     }
 284   else
 285     ui_out_field_string (uiout, "what",
 286                          c->catch_all ? "<any signal>" : "<standard signals>");
 287   ui_out_text (uiout, "\" ");
 288
 289   if (ui_out_is_mi_like_p (uiout))
 290     ui_out_field_string (uiout, "catch-type", "signal");
 291 }
 292
 293 /* Implement the "print_mention" breakpoint_ops method for signal
 294    catchpoints.  */
 295
 296 static void
 297 signal_catchpoint_print_mention (struct breakpoint *b)
 298 {
 299   struct signal_catchpoint *c = (void *) b;
 300
 301   if (c->signals_to_be_caught)
 302     {
 303       int i;
 304       gdb_signal_type iter;
 305
 306       if (VEC_length (gdb_signal_type, c->signals_to_be_caught) > 1)
 307         printf_filtered (_("Catchpoint %d (signals"), b->number);
 308       else
 309         printf_filtered (_("Catchpoint %d (signal"), b->number);
 310
 311       for (i = 0;
 312            VEC_iterate (gdb_signal_type, c->signals_to_be_caught, i, iter);
 313            i++)
 314         {
 315           const char *name = signal_to_name_or_int (iter);
 316
 317           printf_filtered (" %s", name);
 318         }
 319       printf_filtered (")");
 320     }
 321   else if (c->catch_all)
 322     printf_filtered (_("Catchpoint %d (any signal)"), b->number);
 323   else
 324     printf_filtered (_("Catchpoint %d (standard signals)"), b->number);
 325 }
 326
 327 /* Implement the "print_recreate" breakpoint_ops method for signal
 328    catchpoints.  */
 329
 330 static void
 331 signal_catchpoint_print_recreate (struct breakpoint *b, struct ui_file *fp)
 332 {
 333   struct signal_catchpoint *c = (void *) b;
 334
 335   fprintf_unfiltered (fp, "catch signal");
 336
 337   if (c->signals_to_be_caught)
 338     {
 339       int i;
 340       gdb_signal_type iter;
 341
 342       for (i = 0;
 343            VEC_iterate (gdb_signal_type, c->signals_to_be_caught, i, iter);
 344            i++)
 345         fprintf_unfiltered (fp, " %s", signal_to_name_or_int (iter));
 346     }
 347   else if (c->catch_all)
 348     fprintf_unfiltered (fp, " all");
 349 }
 350
 351 /* Implement the "explains_signal" breakpoint_ops method for signal
 352    catchpoints.  */
 353
 354 static int
 355 signal_catchpoint_explains_signal (struct breakpoint *b, enum gdb_signal sig)
 356 {
 357   return 1;
 358 }
 359
 360 /* Create a new signal catchpoint.  TEMPFLAG is true if this should be
 361    a temporary catchpoint.  FILTER is the list of signals to catch; it
 362    can be NULL, meaning all signals.  CATCH_ALL is a flag indicating
 363    whether signals used internally by gdb should be caught; it is only
 364    valid if FILTER is NULL.  If FILTER is NULL and CATCH_ALL is zero,
 365    then internal signals like SIGTRAP are not caught.  */
 366
 367 static void
 368 create_signal_catchpoint (int tempflag, VEC (gdb_signal_type) *filter,
 369                           int catch_all)
 370 {
 371   struct signal_catchpoint *c;
 372   struct gdbarch *gdbarch = get_current_arch ();
 373
 374   c = XNEW (struct signal_catchpoint);
 375   init_catchpoint (&c->base, gdbarch, tempflag, NULL, &signal_catchpoint_ops);
 376   c->signals_to_be_caught = filter;
 377   c->catch_all = catch_all;
 378
 379   install_breakpoint (0, &c->base, 1);
 380 }
 381
 382
 383 /* Splits the argument using space as delimiter.  Returns an xmalloc'd
 384    filter list, or NULL if no filtering is required.  */
 385
 386 static VEC (gdb_signal_type) *
 387 catch_signal_split_args (char *arg, int *catch_all)
 388 {
 389   VEC (gdb_signal_type) *result = NULL;
 390   struct cleanup *cleanup = make_cleanup (VEC_cleanup (gdb_signal_type),
 391                                           &result);
 392   int first = 1;
 393
 394   while (*arg != '\0')
 395     {
 396       int num;
 397       gdb_signal_type signal_number;
 398       char *one_arg, *endptr;
 399       struct cleanup *inner_cleanup;
 400
 401       one_arg = extract_arg (&arg);
 402       if (one_arg == NULL)
 403         break;
 404       inner_cleanup = make_cleanup (xfree, one_arg);
 405
 406       /* Check for the special flag "all".  */
 407       if (strcmp (one_arg, "all") == 0)
 408         {
 409           arg = skip_spaces (arg);
 410           if (*arg != '\0' || !first)
 411             error (_("'all' cannot be caught with other signals"));
 412           *catch_all = 1;
 413           gdb_assert (result == NULL);
 414           do_cleanups (inner_cleanup);
 415           discard_cleanups (cleanup);
 416           return NULL;
 417         }
 418
 419       first = 0;
 420
 421       /* Check if the user provided a signal name or a number.  */
 422       num = (int) strtol (one_arg, &endptr, 0);
 423       if (*endptr == '\0')
 424         signal_number = gdb_signal_from_command (num);
 425       else
 426         {
 427           signal_number = gdb_signal_from_name (one_arg);
 428           if (signal_number == GDB_SIGNAL_UNKNOWN)
 429             error (_("Unknown signal name '%s'."), one_arg);
 430         }
 431
 432       VEC_safe_push (gdb_signal_type, result, signal_number);
 433       do_cleanups (inner_cleanup);
 434     }
 435
 436   discard_cleanups (cleanup);
 437   return result;
 438 }
 439
 440 /* Implement the "catch signal" command.  */
 441
 442 static void
 443 catch_signal_command (char *arg, int from_tty,
 444                       struct cmd_list_element *command)
 445 {
 446   int tempflag, catch_all = 0;
 447   VEC (gdb_signal_type) *filter;
 448
 449   tempflag = get_cmd_context (command) == CATCH_TEMPORARY;
 450
 451   arg = skip_spaces (arg);
 452
 453   /* The allowed syntax is:
 454      catch signal
 455      catch signal <name | number> [<name | number> ... <name | number>]
 456
 457      Let's check if there's a signal name.  */
 458
 459   if (arg != NULL)
 460     filter = catch_signal_split_args (arg, &catch_all);
 461   else
 462     filter = NULL;
 463
 464   create_signal_catchpoint (tempflag, filter, catch_all);
 465 }
 466
 467 static void
 468 initialize_signal_catchpoint_ops (void)
 469 {
 470   struct breakpoint_ops *ops;
 471
 472   initialize_breakpoint_ops ();
 473
 474   ops = &signal_catchpoint_ops;
 475   *ops = base_breakpoint_ops;
 476   ops->dtor = signal_catchpoint_dtor;
 477   ops->insert_location = signal_catchpoint_insert_location;
 478   ops->remove_location = signal_catchpoint_remove_location;
 479   ops->breakpoint_hit = signal_catchpoint_breakpoint_hit;
 480   ops->print_it = signal_catchpoint_print_it;
 481   ops->print_one = signal_catchpoint_print_one;
 482   ops->print_mention = signal_catchpoint_print_mention;
 483   ops->print_recreate = signal_catchpoint_print_recreate;
 484   ops->explains_signal = signal_catchpoint_explains_signal;
 485 }
 486
 487 initialize_file_ftype _initialize_break_catch_sig;
 488
 489 void
 490 _initialize_break_catch_sig (void)
 491 {
 492   initialize_signal_catchpoint_ops ();
 493
 494   signal_catch_counts = XCNEWVEC (unsigned int, GDB_SIGNAL_LAST);
 495
 496   add_catch_command ("signal", _("\
 497 Catch signals by their names and/or numbers.\n\
 498 Usage: catch signal [[NAME|NUMBER] [NAME|NUMBER]...|all]\n\
 499 Arguments say which signals to catch.  If no arguments\n\
 500 are given, every \"normal\" signal will be caught.\n\
 501 The argument \"all\" means to also catch signals used by GDB.\n\
 502 Arguments, if given, should be one or more signal names\n\
 503 (if your system supports that), or signal numbers."),
 504                      catch_signal_command,
 505                      signal_completer,
 506                      CATCH_PERMANENT,
 507                      CATCH_TEMPORARY);
 508 }