gdb/break-catch-sig.c

   1 /* Everything about signal catchpoints, for GDB.
   2
   3    Copyright (C) 2011-2022 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 #include "cli/cli-decode.h"
  33
  34 #include <string>
  35
  36 #define INTERNAL_SIGNAL(x) ((x) == GDB_SIGNAL_TRAP || (x) == GDB_SIGNAL_INT)
  37
  38 /* An instance of this type is used to represent a signal
  39    catchpoint.  */
  40
  41 struct signal_catchpoint : public catchpoint
  42 {
  43   signal_catchpoint (struct gdbarch *gdbarch, bool temp,
  44                      std::vector<gdb_signal> &&sigs,
  45                      bool catch_all_)
  46     : catchpoint (gdbarch, temp, nullptr),
  47       signals_to_be_caught (std::move (sigs)),
  48       catch_all (catch_all_)
  49   {
  50   }
  51
  52   int insert_location (struct bp_location *) override;
  53   int remove_location (struct bp_location *,
  54                        enum remove_bp_reason reason) override;
  55   int breakpoint_hit (const struct bp_location *bl,
  56                       const address_space *aspace,
  57                       CORE_ADDR bp_addr,
  58                       const target_waitstatus &ws) override;
  59   enum print_stop_action print_it (const bpstat *bs) const override;
  60   bool print_one (bp_location **) const override;
  61   void print_mention () const override;
  62   void print_recreate (struct ui_file *fp) const override;
  63   bool explains_signal (enum gdb_signal) override;
  64
  65   /* Signal numbers used for the 'catch signal' feature.  If no signal
  66      has been specified for filtering, it is empty.  Otherwise,
  67      it holds a list of all signals to be caught.  */
  68
  69   std::vector<gdb_signal> signals_to_be_caught;
  70
  71   /* If SIGNALS_TO_BE_CAUGHT is empty, then all "ordinary" signals are
  72      caught.  If CATCH_ALL is true, then internal signals are caught
  73      as well.  If SIGNALS_TO_BE_CAUGHT is not empty, then this field
  74      is ignored.  */
  75
  76   bool catch_all;
  77 };
  78
  79 /* Count of each signal.  */
  80
  81 static unsigned int signal_catch_counts[GDB_SIGNAL_LAST];
  82
  83 \f
  84
  85 /* A convenience wrapper for gdb_signal_to_name that returns the
  86    integer value if the name is not known.  */
  87
  88 static const char *
  89 signal_to_name_or_int (enum gdb_signal sig)
  90 {
  91   const char *result = gdb_signal_to_name (sig);
  92
  93   if (strcmp (result, "?") == 0)
  94     result = plongest (sig);
  95
  96   return result;
  97 }
  98
  99 \f
 100
 101 /* Implement the "insert_location" method for signal catchpoints.  */
 102
 103 int
 104 signal_catchpoint::insert_location (struct bp_location *bl)
 105 {
 106   struct signal_catchpoint *c = (struct signal_catchpoint *) bl->owner;
 107
 108   if (!c->signals_to_be_caught.empty ())
 109     {
 110       for (gdb_signal iter : c->signals_to_be_caught)
 111         ++signal_catch_counts[iter];
 112     }
 113   else
 114     {
 115       for (int i = 0; i < GDB_SIGNAL_LAST; ++i)
 116         {
 117           if (c->catch_all || !INTERNAL_SIGNAL (i))
 118             ++signal_catch_counts[i];
 119         }
 120     }
 121
 122   signal_catch_update (signal_catch_counts);
 123
 124   return 0;
 125 }
 126
 127 /* Implement the "remove_location" method for signal catchpoints.  */
 128
 129 int
 130 signal_catchpoint::remove_location (struct bp_location *bl,
 131                                     enum remove_bp_reason reason)
 132 {
 133   struct signal_catchpoint *c = (struct signal_catchpoint *) bl->owner;
 134
 135   if (!c->signals_to_be_caught.empty ())
 136     {
 137       for (gdb_signal iter : c->signals_to_be_caught)
 138         {
 139           gdb_assert (signal_catch_counts[iter] > 0);
 140           --signal_catch_counts[iter];
 141         }
 142     }
 143   else
 144     {
 145       for (int i = 0; i < GDB_SIGNAL_LAST; ++i)
 146         {
 147           if (c->catch_all || !INTERNAL_SIGNAL (i))
 148             {
 149               gdb_assert (signal_catch_counts[i] > 0);
 150               --signal_catch_counts[i];
 151             }
 152         }
 153     }
 154
 155   signal_catch_update (signal_catch_counts);
 156
 157   return 0;
 158 }
 159
 160 /* Implement the "breakpoint_hit" method for signal catchpoints.  */
 161
 162 int
 163 signal_catchpoint::breakpoint_hit (const struct bp_location *bl,
 164                                    const address_space *aspace,
 165                                    CORE_ADDR bp_addr,
 166                                    const target_waitstatus &ws)
 167 {
 168   const struct signal_catchpoint *c
 169     = (const struct signal_catchpoint *) bl->owner;
 170   gdb_signal signal_number;
 171
 172   if (ws.kind () != TARGET_WAITKIND_STOPPED)
 173     return 0;
 174
 175   signal_number = ws.sig ();
 176
 177   /* If we are catching specific signals in this breakpoint, then we
 178      must guarantee that the called signal is the same signal we are
 179      catching.  */
 180   if (!c->signals_to_be_caught.empty ())
 181     {
 182       for (gdb_signal iter : c->signals_to_be_caught)
 183         if (signal_number == iter)
 184           return 1;
 185       /* Not the same.  */
 186       return 0;
 187     }
 188   else
 189     return c->catch_all || !INTERNAL_SIGNAL (signal_number);
 190 }
 191
 192 /* Implement the "print_it" method for signal catchpoints.  */
 193
 194 enum print_stop_action
 195 signal_catchpoint::print_it (const bpstat *bs) const
 196 {
 197   struct target_waitstatus last;
 198   const char *signal_name;
 199   struct ui_out *uiout = current_uiout;
 200
 201   get_last_target_status (nullptr, nullptr, &last);
 202
 203   signal_name = signal_to_name_or_int (last.sig ());
 204
 205   annotate_catchpoint (number);
 206   maybe_print_thread_hit_breakpoint (uiout);
 207
 208   gdb_printf (_("Catchpoint %d (signal %s), "), number, signal_name);
 209
 210   return PRINT_SRC_AND_LOC;
 211 }
 212
 213 /* Implement the "print_one" method for signal catchpoints.  */
 214
 215 bool
 216 signal_catchpoint::print_one (bp_location **last_loc) const
 217 {
 218   struct value_print_options opts;
 219   struct ui_out *uiout = current_uiout;
 220
 221   get_user_print_options (&opts);
 222
 223   /* Field 4, the address, is omitted (which makes the columns
 224      not line up too nicely with the headers, but the effect
 225      is relatively readable).  */
 226   if (opts.addressprint)
 227     uiout->field_skip ("addr");
 228   annotate_field (5);
 229
 230   if (signals_to_be_caught.size () > 1)
 231     uiout->text ("signals \"");
 232   else
 233     uiout->text ("signal \"");
 234
 235   if (!signals_to_be_caught.empty ())
 236     {
 237       std::string text;
 238
 239       bool first = true;
 240       for (gdb_signal iter : signals_to_be_caught)
 241         {
 242           const char *name = signal_to_name_or_int (iter);
 243
 244           if (!first)
 245             text += " ";
 246           first = false;
 247
 248           text += name;
 249         }
 250       uiout->field_string ("what", text);
 251     }
 252   else
 253     uiout->field_string ("what",
 254                          catch_all ? "<any signal>" : "<standard signals>",
 255                          metadata_style.style ());
 256   uiout->text ("\" ");
 257
 258   if (uiout->is_mi_like_p ())
 259     uiout->field_string ("catch-type", "signal");
 260
 261   return true;
 262 }
 263
 264 /* Implement the "print_mention" method for signal catchpoints.  */
 265
 266 void
 267 signal_catchpoint::print_mention () const
 268 {
 269   if (!signals_to_be_caught.empty ())
 270     {
 271       if (signals_to_be_caught.size () > 1)
 272         gdb_printf (_("Catchpoint %d (signals"), number);
 273       else
 274         gdb_printf (_("Catchpoint %d (signal"), number);
 275
 276       for (gdb_signal iter : signals_to_be_caught)
 277         {
 278           const char *name = signal_to_name_or_int (iter);
 279
 280           gdb_printf (" %s", name);
 281         }
 282       gdb_printf (")");
 283     }
 284   else if (catch_all)
 285     gdb_printf (_("Catchpoint %d (any signal)"), number);
 286   else
 287     gdb_printf (_("Catchpoint %d (standard signals)"), number);
 288 }
 289
 290 /* Implement the "print_recreate" method for signal catchpoints.  */
 291
 292 void
 293 signal_catchpoint::print_recreate (struct ui_file *fp) const
 294 {
 295   gdb_printf (fp, "catch signal");
 296
 297   if (!signals_to_be_caught.empty ())
 298     {
 299       for (gdb_signal iter : signals_to_be_caught)
 300         gdb_printf (fp, " %s", signal_to_name_or_int (iter));
 301     }
 302   else if (catch_all)
 303     gdb_printf (fp, " all");
 304   gdb_putc ('\n', fp);
 305 }
 306
 307 /* Implement the "explains_signal" method for signal catchpoints.  */
 308
 309 bool
 310 signal_catchpoint::explains_signal (enum gdb_signal sig)
 311 {
 312   return true;
 313 }
 314
 315 /* Create a new signal catchpoint.  TEMPFLAG is true if this should be
 316    a temporary catchpoint.  FILTER is the list of signals to catch; it
 317    can be empty, meaning all signals.  CATCH_ALL is a flag indicating
 318    whether signals used internally by gdb should be caught; it is only
 319    valid if FILTER is NULL.  If FILTER is empty and CATCH_ALL is zero,
 320    then internal signals like SIGTRAP are not caught.  */
 321
 322 static void
 323 create_signal_catchpoint (int tempflag, std::vector<gdb_signal> &&filter,
 324                           bool catch_all)
 325 {
 326   struct gdbarch *gdbarch = get_current_arch ();
 327
 328   std::unique_ptr<signal_catchpoint> c
 329     (new signal_catchpoint (gdbarch, tempflag, std::move (filter), catch_all));
 330
 331   install_breakpoint (0, std::move (c), 1);
 332 }
 333
 334
 335 /* Splits the argument using space as delimiter.  Returns a filter
 336    list, which is empty if no filtering is required.  */
 337
 338 static std::vector<gdb_signal>
 339 catch_signal_split_args (const char *arg, bool *catch_all)
 340 {
 341   std::vector<gdb_signal> result;
 342   bool first = true;
 343
 344   while (*arg != '\0')
 345     {
 346       int num;
 347       gdb_signal signal_number;
 348       char *endptr;
 349
 350       std::string one_arg = extract_arg (&arg);
 351       if (one_arg.empty ())
 352         break;
 353
 354       /* Check for the special flag "all".  */
 355       if (one_arg == "all")
 356         {
 357           arg = skip_spaces (arg);
 358           if (*arg != '\0' || !first)
 359             error (_("'all' cannot be caught with other signals"));
 360           *catch_all = true;
 361           gdb_assert (result.empty ());
 362           return result;
 363         }
 364
 365       first = false;
 366
 367       /* Check if the user provided a signal name or a number.  */
 368       num = (int) strtol (one_arg.c_str (), &endptr, 0);
 369       if (*endptr == '\0')
 370         signal_number = gdb_signal_from_command (num);
 371       else
 372         {
 373           signal_number = gdb_signal_from_name (one_arg.c_str ());
 374           if (signal_number == GDB_SIGNAL_UNKNOWN)
 375             error (_("Unknown signal name '%s'."), one_arg.c_str ());
 376         }
 377
 378       result.push_back (signal_number);
 379     }
 380
 381   result.shrink_to_fit ();
 382   return result;
 383 }
 384
 385 /* Implement the "catch signal" command.  */
 386
 387 static void
 388 catch_signal_command (const char *arg, int from_tty,
 389                       struct cmd_list_element *command)
 390 {
 391   int tempflag;
 392   bool catch_all = false;
 393   std::vector<gdb_signal> filter;
 394
 395   tempflag = command->context () == CATCH_TEMPORARY;
 396
 397   arg = skip_spaces (arg);
 398
 399   /* The allowed syntax is:
 400      catch signal
 401      catch signal <name | number> [<name | number> ... <name | number>]
 402
 403      Let's check if there's a signal name.  */
 404
 405   if (arg != NULL)
 406     filter = catch_signal_split_args (arg, &catch_all);
 407
 408   create_signal_catchpoint (tempflag, std::move (filter), catch_all);
 409 }
 410
 411 void _initialize_break_catch_sig ();
 412 void
 413 _initialize_break_catch_sig ()
 414 {
 415   add_catch_command ("signal", _("\
 416 Catch signals by their names and/or numbers.\n\
 417 Usage: catch signal [[NAME|NUMBER] [NAME|NUMBER]...|all]\n\
 418 Arguments say which signals to catch.  If no arguments\n\
 419 are given, every \"normal\" signal will be caught.\n\
 420 The argument \"all\" means to also catch signals used by GDB.\n\
 421 Arguments, if given, should be one or more signal names\n\
 422 (if your system supports that), or signal numbers."),
 423                      catch_signal_command,
 424                      signal_completer,
 425                      CATCH_PERMANENT,
 426                      CATCH_TEMPORARY);
 427 }