gdb/break-catch-sig.c

   1 /* Everything about signal catchpoints, for GDB.
   2
   3    Copyright (C) 2011-2020 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 "cli/cli-style.h"
  32
  33 #include <string>
  34
  35 #define INTERNAL_SIGNAL(x) ((x) == GDB_SIGNAL_TRAP || (x) == GDB_SIGNAL_INT)
  36
  37 /* An instance of this type is used to represent a signal catchpoint.
  38    A breakpoint is really of this type iff its ops pointer points to
  39    SIGNAL_CATCHPOINT_OPS.  */
  40
  41 struct signal_catchpoint : public breakpoint
  42 {
  43   /* Signal numbers used for the 'catch signal' feature.  If no signal
  44      has been specified for filtering, it is empty.  Otherwise,
  45      it holds a list of all signals to be caught.  */
  46
  47   std::vector<gdb_signal> signals_to_be_caught;
  48
  49   /* If SIGNALS_TO_BE_CAUGHT is empty, then all "ordinary" signals are
  50      caught.  If CATCH_ALL is true, then internal signals are caught
  51      as well.  If SIGNALS_TO_BE_CAUGHT is not empty, then this field
  52      is ignored.  */
  53
  54   bool catch_all;
  55 };
  56
  57 /* The breakpoint_ops structure to be used in signal catchpoints.  */
  58
  59 static struct breakpoint_ops signal_catchpoint_ops;
  60
  61 /* Count of each signal.  */
  62
  63 static unsigned int signal_catch_counts[GDB_SIGNAL_LAST];
  64
  65 \f
  66
  67 /* A convenience wrapper for gdb_signal_to_name that returns the
  68    integer value if the name is not known.  */
  69
  70 static const char *
  71 signal_to_name_or_int (enum gdb_signal sig)
  72 {
  73   const char *result = gdb_signal_to_name (sig);
  74
  75   if (strcmp (result, "?") == 0)
  76     result = plongest (sig);
  77
  78   return result;
  79 }
  80
  81 \f
  82
  83 /* Implement the "insert_location" breakpoint_ops method for signal
  84    catchpoints.  */
  85
  86 static int
  87 signal_catchpoint_insert_location (struct bp_location *bl)
  88 {
  89   struct signal_catchpoint *c = (struct signal_catchpoint *) bl->owner;
  90
  91   if (!c->signals_to_be_caught.empty ())
  92     {
  93       for (gdb_signal iter : c->signals_to_be_caught)
  94         ++signal_catch_counts[iter];
  95     }
  96   else
  97     {
  98       for (int i = 0; i < GDB_SIGNAL_LAST; ++i)
  99         {
 100           if (c->catch_all || !INTERNAL_SIGNAL (i))
 101             ++signal_catch_counts[i];
 102         }
 103     }
 104
 105   signal_catch_update (signal_catch_counts);
 106
 107   return 0;
 108 }
 109
 110 /* Implement the "remove_location" breakpoint_ops method for signal
 111    catchpoints.  */
 112
 113 static int
 114 signal_catchpoint_remove_location (struct bp_location *bl,
 115                                    enum remove_bp_reason reason)
 116 {
 117   struct signal_catchpoint *c = (struct signal_catchpoint *) bl->owner;
 118
 119   if (!c->signals_to_be_caught.empty ())
 120     {
 121       for (gdb_signal iter : c->signals_to_be_caught)
 122         {
 123           gdb_assert (signal_catch_counts[iter] > 0);
 124           --signal_catch_counts[iter];
 125         }
 126     }
 127   else
 128     {
 129       for (int i = 0; i < GDB_SIGNAL_LAST; ++i)
 130         {
 131           if (c->catch_all || !INTERNAL_SIGNAL (i))
 132             {
 133               gdb_assert (signal_catch_counts[i] > 0);
 134               --signal_catch_counts[i];
 135             }
 136         }
 137     }
 138
 139   signal_catch_update (signal_catch_counts);
 140
 141   return 0;
 142 }
 143
 144 /* Implement the "breakpoint_hit" breakpoint_ops method for signal
 145    catchpoints.  */
 146
 147 static int
 148 signal_catchpoint_breakpoint_hit (const struct bp_location *bl,
 149                                   const address_space *aspace,
 150                                   CORE_ADDR bp_addr,
 151                                   const struct target_waitstatus *ws)
 152 {
 153   const struct signal_catchpoint *c
 154     = (const struct signal_catchpoint *) bl->owner;
 155   gdb_signal signal_number;
 156
 157   if (ws->kind != TARGET_WAITKIND_STOPPED)
 158     return 0;
 159
 160   signal_number = ws->value.sig;
 161
 162   /* If we are catching specific signals in this breakpoint, then we
 163      must guarantee that the called signal is the same signal we are
 164      catching.  */
 165   if (!c->signals_to_be_caught.empty ())
 166     {
 167       for (gdb_signal iter : c->signals_to_be_caught)
 168         if (signal_number == iter)
 169           return 1;
 170       /* Not the same.  */
 171       return 0;
 172     }
 173   else
 174     return c->catch_all || !INTERNAL_SIGNAL (signal_number);
 175 }
 176
 177 /* Implement the "print_it" breakpoint_ops method for signal
 178    catchpoints.  */
 179
 180 static enum print_stop_action
 181 signal_catchpoint_print_it (bpstat bs)
 182 {
 183   struct breakpoint *b = bs->breakpoint_at;
 184   struct target_waitstatus last;
 185   const char *signal_name;
 186   struct ui_out *uiout = current_uiout;
 187
 188   get_last_target_status (nullptr, nullptr, &last);
 189
 190   signal_name = signal_to_name_or_int (last.value.sig);
 191
 192   annotate_catchpoint (b->number);
 193   maybe_print_thread_hit_breakpoint (uiout);
 194
 195   printf_filtered (_("Catchpoint %d (signal %s), "), b->number, signal_name);
 196
 197   return PRINT_SRC_AND_LOC;
 198 }
 199
 200 /* Implement the "print_one" breakpoint_ops method for signal
 201    catchpoints.  */
 202
 203 static void
 204 signal_catchpoint_print_one (struct breakpoint *b,
 205                              struct bp_location **last_loc)
 206 {
 207   struct signal_catchpoint *c = (struct signal_catchpoint *) b;
 208   struct value_print_options opts;
 209   struct ui_out *uiout = current_uiout;
 210
 211   get_user_print_options (&opts);
 212
 213   /* Field 4, the address, is omitted (which makes the columns
 214      not line up too nicely with the headers, but the effect
 215      is relatively readable).  */
 216   if (opts.addressprint)
 217     uiout->field_skip ("addr");
 218   annotate_field (5);
 219
 220   if (c->signals_to_be_caught.size () > 1)
 221     uiout->text ("signals \"");
 222   else
 223     uiout->text ("signal \"");
 224
 225   if (!c->signals_to_be_caught.empty ())
 226     {
 227       std::string text;
 228
 229       bool first = true;
 230       for (gdb_signal iter : c->signals_to_be_caught)
 231         {
 232           const char *name = signal_to_name_or_int (iter);
 233
 234           if (!first)
 235             text += " ";
 236           first = false;
 237
 238           text += name;
 239         }
 240       uiout->field_string ("what", text.c_str ());
 241     }
 242   else
 243     uiout->field_string ("what",
 244                          c->catch_all ? "<any signal>" : "<standard signals>",
 245                          metadata_style.style ());
 246   uiout->text ("\" ");
 247
 248   if (uiout->is_mi_like_p ())
 249     uiout->field_string ("catch-type", "signal");
 250 }
 251
 252 /* Implement the "print_mention" breakpoint_ops method for signal
 253    catchpoints.  */
 254
 255 static void
 256 signal_catchpoint_print_mention (struct breakpoint *b)
 257 {
 258   struct signal_catchpoint *c = (struct signal_catchpoint *) b;
 259
 260   if (!c->signals_to_be_caught.empty ())
 261     {
 262       if (c->signals_to_be_caught.size () > 1)
 263         printf_filtered (_("Catchpoint %d (signals"), b->number);
 264       else
 265         printf_filtered (_("Catchpoint %d (signal"), b->number);
 266
 267       for (gdb_signal iter : c->signals_to_be_caught)
 268         {
 269           const char *name = signal_to_name_or_int (iter);
 270
 271           printf_filtered (" %s", name);
 272         }
 273       printf_filtered (")");
 274     }
 275   else if (c->catch_all)
 276     printf_filtered (_("Catchpoint %d (any signal)"), b->number);
 277   else
 278     printf_filtered (_("Catchpoint %d (standard signals)"), b->number);
 279 }
 280
 281 /* Implement the "print_recreate" breakpoint_ops method for signal
 282    catchpoints.  */
 283
 284 static void
 285 signal_catchpoint_print_recreate (struct breakpoint *b, struct ui_file *fp)
 286 {
 287   struct signal_catchpoint *c = (struct signal_catchpoint *) b;
 288
 289   fprintf_unfiltered (fp, "catch signal");
 290
 291   if (!c->signals_to_be_caught.empty ())
 292     {
 293       for (gdb_signal iter : c->signals_to_be_caught)
 294         fprintf_unfiltered (fp, " %s", signal_to_name_or_int (iter));
 295     }
 296   else if (c->catch_all)
 297     fprintf_unfiltered (fp, " all");
 298   fputc_unfiltered ('\n', fp);
 299 }
 300
 301 /* Implement the "explains_signal" breakpoint_ops method for signal
 302    catchpoints.  */
 303
 304 static int
 305 signal_catchpoint_explains_signal (struct breakpoint *b, enum gdb_signal sig)
 306 {
 307   return 1;
 308 }
 309
 310 /* Create a new signal catchpoint.  TEMPFLAG is true if this should be
 311    a temporary catchpoint.  FILTER is the list of signals to catch; it
 312    can be empty, meaning all signals.  CATCH_ALL is a flag indicating
 313    whether signals used internally by gdb should be caught; it is only
 314    valid if FILTER is NULL.  If FILTER is empty and CATCH_ALL is zero,
 315    then internal signals like SIGTRAP are not caught.  */
 316
 317 static void
 318 create_signal_catchpoint (int tempflag, std::vector<gdb_signal> &&filter,
 319                           bool catch_all)
 320 {
 321   struct gdbarch *gdbarch = get_current_arch ();
 322
 323   std::unique_ptr<signal_catchpoint> c (new signal_catchpoint ());
 324   init_catchpoint (c.get (), gdbarch, tempflag, NULL, &signal_catchpoint_ops);
 325   c->signals_to_be_caught = std::move (filter);
 326   c->catch_all = catch_all;
 327
 328   install_breakpoint (0, std::move (c), 1);
 329 }
 330
 331
 332 /* Splits the argument using space as delimiter.  Returns a filter
 333    list, which is empty if no filtering is required.  */
 334
 335 static std::vector<gdb_signal>
 336 catch_signal_split_args (const char *arg, bool *catch_all)
 337 {
 338   std::vector<gdb_signal> result;
 339   bool first = true;
 340
 341   while (*arg != '\0')
 342     {
 343       int num;
 344       gdb_signal signal_number;
 345       char *endptr;
 346
 347       std::string one_arg = extract_arg (&arg);
 348       if (one_arg.empty ())
 349         break;
 350
 351       /* Check for the special flag "all".  */
 352       if (one_arg == "all")
 353         {
 354           arg = skip_spaces (arg);
 355           if (*arg != '\0' || !first)
 356             error (_("'all' cannot be caught with other signals"));
 357           *catch_all = true;
 358           gdb_assert (result.empty ());
 359           return result;
 360         }
 361
 362       first = false;
 363
 364       /* Check if the user provided a signal name or a number.  */
 365       num = (int) strtol (one_arg.c_str (), &endptr, 0);
 366       if (*endptr == '\0')
 367         signal_number = gdb_signal_from_command (num);
 368       else
 369         {
 370           signal_number = gdb_signal_from_name (one_arg.c_str ());
 371           if (signal_number == GDB_SIGNAL_UNKNOWN)
 372             error (_("Unknown signal name '%s'."), one_arg.c_str ());
 373         }
 374
 375       result.push_back (signal_number);
 376     }
 377
 378   result.shrink_to_fit ();
 379   return result;
 380 }
 381
 382 /* Implement the "catch signal" command.  */
 383
 384 static void
 385 catch_signal_command (const char *arg, int from_tty,
 386                       struct cmd_list_element *command)
 387 {
 388   int tempflag;
 389   bool catch_all = false;
 390   std::vector<gdb_signal> filter;
 391
 392   tempflag = get_cmd_context (command) == CATCH_TEMPORARY;
 393
 394   arg = skip_spaces (arg);
 395
 396   /* The allowed syntax is:
 397      catch signal
 398      catch signal <name | number> [<name | number> ... <name | number>]
 399
 400      Let's check if there's a signal name.  */
 401
 402   if (arg != NULL)
 403     filter = catch_signal_split_args (arg, &catch_all);
 404
 405   create_signal_catchpoint (tempflag, std::move (filter), catch_all);
 406 }
 407
 408 static void
 409 initialize_signal_catchpoint_ops (void)
 410 {
 411   struct breakpoint_ops *ops;
 412
 413   initialize_breakpoint_ops ();
 414
 415   ops = &signal_catchpoint_ops;
 416   *ops = base_breakpoint_ops;
 417   ops->insert_location = signal_catchpoint_insert_location;
 418   ops->remove_location = signal_catchpoint_remove_location;
 419   ops->breakpoint_hit = signal_catchpoint_breakpoint_hit;
 420   ops->print_it = signal_catchpoint_print_it;
 421   ops->print_one = signal_catchpoint_print_one;
 422   ops->print_mention = signal_catchpoint_print_mention;
 423   ops->print_recreate = signal_catchpoint_print_recreate;
 424   ops->explains_signal = signal_catchpoint_explains_signal;
 425 }
 426
 427 void _initialize_break_catch_sig ();
 428 void
 429 _initialize_break_catch_sig ()
 430 {
 431   initialize_signal_catchpoint_ops ();
 432
 433   add_catch_command ("signal", _("\
 434 Catch signals by their names and/or numbers.\n\
 435 Usage: catch signal [[NAME|NUMBER] [NAME|NUMBER]...|all]\n\
 436 Arguments say which signals to catch.  If no arguments\n\
 437 are given, every \"normal\" signal will be caught.\n\
 438 The argument \"all\" means to also catch signals used by GDB.\n\
 439 Arguments, if given, should be one or more signal names\n\
 440 (if your system supports that), or signal numbers."),
 441                      catch_signal_command,
 442                      signal_completer,
 443                      CATCH_PERMANENT,
 444                      CATCH_TEMPORARY);
 445 }