gdb/break-catch-sig.c

   1 /* Everything about signal catchpoints, for GDB.
   2
   3    Copyright (C) 2011-2024 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 "arch-utils.h"
  21 #include <ctype.h>
  22 #include "breakpoint.h"
  23 #include "gdbcmd.h"
  24 #include "inferior.h"
  25 #include "infrun.h"
  26 #include "annotate.h"
  27 #include "valprint.h"
  28 #include "cli/cli-utils.h"
  29 #include "completer.h"
  30 #include "cli/cli-style.h"
  31 #include "cli/cli-decode.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
  38    catchpoint.  */
  39
  40 struct signal_catchpoint : public catchpoint
  41 {
  42   signal_catchpoint (struct gdbarch *gdbarch, bool temp,
  43                      std::vector<gdb_signal> &&sigs,
  44                      bool catch_all_)
  45     : catchpoint (gdbarch, temp, nullptr),
  46       signals_to_be_caught (std::move (sigs)),
  47       catch_all (catch_all_)
  48   {
  49   }
  50
  51   int insert_location (struct bp_location *) override;
  52   int remove_location (struct bp_location *,
  53                        enum remove_bp_reason reason) override;
  54   int breakpoint_hit (const struct bp_location *bl,
  55                       const address_space *aspace,
  56                       CORE_ADDR bp_addr,
  57                       const target_waitstatus &ws) override;
  58   enum print_stop_action print_it (const bpstat *bs) const override;
  59   bool print_one (const bp_location **) const override;
  60   void print_mention () const override;
  61   void print_recreate (struct ui_file *fp) const override;
  62   bool explains_signal (enum gdb_signal) override;
  63
  64   /* Signal numbers used for the 'catch signal' feature.  If no signal
  65      has been specified for filtering, it is empty.  Otherwise,
  66      it holds a list of all signals to be caught.  */
  67
  68   std::vector<gdb_signal> signals_to_be_caught;
  69
  70   /* If SIGNALS_TO_BE_CAUGHT is empty, then all "ordinary" signals are
  71      caught.  If CATCH_ALL is true, then internal signals are caught
  72      as well.  If SIGNALS_TO_BE_CAUGHT is not empty, then this field
  73      is ignored.  */
  74
  75   bool catch_all;
  76 };
  77
  78 /* Count of each signal.  */
  79
  80 static unsigned int signal_catch_counts[GDB_SIGNAL_LAST];
  81
  82 \f
  83
  84 /* A convenience wrapper for gdb_signal_to_name that returns the
  85    integer value if the name is not known.  */
  86
  87 static const char *
  88 signal_to_name_or_int (enum gdb_signal sig)
  89 {
  90   const char *result = gdb_signal_to_name (sig);
  91
  92   if (strcmp (result, "?") == 0)
  93     result = plongest (sig);
  94
  95   return result;
  96 }
  97
  98 \f
  99
 100 /* Implement the "insert_location" method for signal catchpoints.  */
 101
 102 int
 103 signal_catchpoint::insert_location (struct bp_location *bl)
 104 {
 105   signal_catchpoint *c
 106     = gdb::checked_static_cast<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   signal_catchpoint *c
 134     = gdb::checked_static_cast<signal_catchpoint *> (bl->owner);
 135
 136   if (!c->signals_to_be_caught.empty ())
 137     {
 138       for (gdb_signal iter : c->signals_to_be_caught)
 139         {
 140           gdb_assert (signal_catch_counts[iter] > 0);
 141           --signal_catch_counts[iter];
 142         }
 143     }
 144   else
 145     {
 146       for (int i = 0; i < GDB_SIGNAL_LAST; ++i)
 147         {
 148           if (c->catch_all || !INTERNAL_SIGNAL (i))
 149             {
 150               gdb_assert (signal_catch_counts[i] > 0);
 151               --signal_catch_counts[i];
 152             }
 153         }
 154     }
 155
 156   signal_catch_update (signal_catch_counts);
 157
 158   return 0;
 159 }
 160
 161 /* Implement the "breakpoint_hit" method for signal catchpoints.  */
 162
 163 int
 164 signal_catchpoint::breakpoint_hit (const struct bp_location *bl,
 165                                    const address_space *aspace,
 166                                    CORE_ADDR bp_addr,
 167                                    const target_waitstatus &ws)
 168 {
 169   const signal_catchpoint *c
 170     = gdb::checked_static_cast<const signal_catchpoint *> (bl->owner);
 171   gdb_signal signal_number;
 172
 173   if (ws.kind () != TARGET_WAITKIND_STOPPED)
 174     return 0;
 175
 176   signal_number = ws.sig ();
 177
 178   /* If we are catching specific signals in this breakpoint, then we
 179      must guarantee that the called signal is the same signal we are
 180      catching.  */
 181   if (!c->signals_to_be_caught.empty ())
 182     {
 183       for (gdb_signal iter : c->signals_to_be_caught)
 184         if (signal_number == iter)
 185           return 1;
 186       /* Not the same.  */
 187       return 0;
 188     }
 189   else
 190     return c->catch_all || !INTERNAL_SIGNAL (signal_number);
 191 }
 192
 193 /* Implement the "print_it" method for signal catchpoints.  */
 194
 195 enum print_stop_action
 196 signal_catchpoint::print_it (const bpstat *bs) const
 197 {
 198   struct target_waitstatus last;
 199   const char *signal_name;
 200   struct ui_out *uiout = current_uiout;
 201
 202   get_last_target_status (nullptr, nullptr, &last);
 203
 204   signal_name = signal_to_name_or_int (last.sig ());
 205
 206   annotate_catchpoint (number);
 207   maybe_print_thread_hit_breakpoint (uiout);
 208
 209   gdb_printf (_("Catchpoint %d (signal %s), "), number, signal_name);
 210
 211   return PRINT_SRC_AND_LOC;
 212 }
 213
 214 /* Implement the "print_one" method for signal catchpoints.  */
 215
 216 bool
 217 signal_catchpoint::print_one (const bp_location **last_loc) const
 218 {
 219   struct value_print_options opts;
 220   struct ui_out *uiout = current_uiout;
 221
 222   get_user_print_options (&opts);
 223
 224   /* Field 4, the address, is omitted (which makes the columns
 225      not line up too nicely with the headers, but the effect
 226      is relatively readable).  */
 227   if (opts.addressprint)
 228     uiout->field_skip ("addr");
 229   annotate_field (5);
 230
 231   if (signals_to_be_caught.size () > 1)
 232     uiout->text ("signals \"");
 233   else
 234     uiout->text ("signal \"");
 235
 236   if (!signals_to_be_caught.empty ())
 237     {
 238       std::string text;
 239
 240       bool first = true;
 241       for (gdb_signal iter : signals_to_be_caught)
 242         {
 243           const char *name = signal_to_name_or_int (iter);
 244
 245           if (!first)
 246             text += " ";
 247           first = false;
 248
 249           text += name;
 250         }
 251       uiout->field_string ("what", text);
 252     }
 253   else
 254     uiout->field_string ("what",
 255                          catch_all ? "<any signal>" : "<standard signals>",
 256                          metadata_style.style ());
 257   uiout->text ("\" ");
 258
 259   if (uiout->is_mi_like_p ())
 260     uiout->field_string ("catch-type", "signal");
 261
 262   return true;
 263 }
 264
 265 /* Implement the "print_mention" method for signal catchpoints.  */
 266
 267 void
 268 signal_catchpoint::print_mention () const
 269 {
 270   if (!signals_to_be_caught.empty ())
 271     {
 272       if (signals_to_be_caught.size () > 1)
 273         gdb_printf (_("Catchpoint %d (signals"), number);
 274       else
 275         gdb_printf (_("Catchpoint %d (signal"), number);
 276
 277       for (gdb_signal iter : signals_to_be_caught)
 278         {
 279           const char *name = signal_to_name_or_int (iter);
 280
 281           gdb_printf (" %s", name);
 282         }
 283       gdb_printf (")");
 284     }
 285   else if (catch_all)
 286     gdb_printf (_("Catchpoint %d (any signal)"), number);
 287   else
 288     gdb_printf (_("Catchpoint %d (standard signals)"), number);
 289 }
 290
 291 /* Implement the "print_recreate" method for signal catchpoints.  */
 292
 293 void
 294 signal_catchpoint::print_recreate (struct ui_file *fp) const
 295 {
 296   gdb_printf (fp, "catch signal");
 297
 298   if (!signals_to_be_caught.empty ())
 299     {
 300       for (gdb_signal iter : signals_to_be_caught)
 301         gdb_printf (fp, " %s", signal_to_name_or_int (iter));
 302     }
 303   else if (catch_all)
 304     gdb_printf (fp, " all");
 305   gdb_putc ('\n', fp);
 306 }
 307
 308 /* Implement the "explains_signal" method for signal catchpoints.  */
 309
 310 bool
 311 signal_catchpoint::explains_signal (enum gdb_signal sig)
 312 {
 313   return true;
 314 }
 315
 316 /* Create a new signal catchpoint.  TEMPFLAG is true if this should be
 317    a temporary catchpoint.  FILTER is the list of signals to catch; it
 318    can be empty, meaning all signals.  CATCH_ALL is a flag indicating
 319    whether signals used internally by gdb should be caught; it is only
 320    valid if FILTER is NULL.  If FILTER is empty and CATCH_ALL is zero,
 321    then internal signals like SIGTRAP are not caught.  */
 322
 323 static void
 324 create_signal_catchpoint (int tempflag, std::vector<gdb_signal> &&filter,
 325                           bool catch_all)
 326 {
 327   struct gdbarch *gdbarch = get_current_arch ();
 328
 329   std::unique_ptr<signal_catchpoint> c
 330     (new signal_catchpoint (gdbarch, tempflag, std::move (filter), catch_all));
 331
 332   install_breakpoint (0, std::move (c), 1);
 333 }
 334
 335
 336 /* Splits the argument using space as delimiter.  Returns a filter
 337    list, which is empty if no filtering is required.  */
 338
 339 static std::vector<gdb_signal>
 340 catch_signal_split_args (const char *arg, bool *catch_all)
 341 {
 342   std::vector<gdb_signal> result;
 343   bool first = true;
 344
 345   while (*arg != '\0')
 346     {
 347       int num;
 348       gdb_signal signal_number;
 349       char *endptr;
 350
 351       std::string one_arg = extract_arg (&arg);
 352       if (one_arg.empty ())
 353         break;
 354
 355       /* Check for the special flag "all".  */
 356       if (one_arg == "all")
 357         {
 358           arg = skip_spaces (arg);
 359           if (*arg != '\0' || !first)
 360             error (_("'all' cannot be caught with other signals"));
 361           *catch_all = true;
 362           gdb_assert (result.empty ());
 363           return result;
 364         }
 365
 366       first = false;
 367
 368       /* Check if the user provided a signal name or a number.  */
 369       num = (int) strtol (one_arg.c_str (), &endptr, 0);
 370       if (*endptr == '\0')
 371         signal_number = gdb_signal_from_command (num);
 372       else
 373         {
 374           signal_number = gdb_signal_from_name (one_arg.c_str ());
 375           if (signal_number == GDB_SIGNAL_UNKNOWN)
 376             error (_("Unknown signal name '%s'."), one_arg.c_str ());
 377         }
 378
 379       result.push_back (signal_number);
 380     }
 381
 382   result.shrink_to_fit ();
 383   return result;
 384 }
 385
 386 /* Implement the "catch signal" command.  */
 387
 388 static void
 389 catch_signal_command (const char *arg, int from_tty,
 390                       struct cmd_list_element *command)
 391 {
 392   int tempflag;
 393   bool catch_all = false;
 394   std::vector<gdb_signal> filter;
 395
 396   tempflag = command->context () == CATCH_TEMPORARY;
 397
 398   arg = skip_spaces (arg);
 399
 400   /* The allowed syntax is:
 401      catch signal
 402      catch signal <name | number> [<name | number> ... <name | number>]
 403
 404      Let's check if there's a signal name.  */
 405
 406   if (arg != NULL)
 407     filter = catch_signal_split_args (arg, &catch_all);
 408
 409   create_signal_catchpoint (tempflag, std::move (filter), catch_all);
 410 }
 411
 412 void _initialize_break_catch_sig ();
 413 void
 414 _initialize_break_catch_sig ()
 415 {
 416   add_catch_command ("signal", _("\
 417 Catch signals by their names and/or numbers.\n\
 418 Usage: catch signal [[NAME|NUMBER] [NAME|NUMBER]...|all]\n\
 419 Arguments say which signals to catch.  If no arguments\n\
 420 are given, every \"normal\" signal will be caught.\n\
 421 The argument \"all\" means to also catch signals used by GDB.\n\
 422 Arguments, if given, should be one or more signal names\n\
 423 (if your system supports that), or signal numbers."),
 424                      catch_signal_command,
 425                      signal_completer,
 426                      CATCH_PERMANENT,
 427                      CATCH_TEMPORARY);
 428 }