gdb/break-catch-fork.c

   1 /* Everything about vfork catchpoints, for GDB.
   2
   3    Copyright (C) 1986-2022 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
  22 #include "annotate.h"
  23 #include "arch-utils.h"
  24 #include "breakpoint.h"
  25 #include "cli/cli-decode.h"
  26 #include "inferior.h"
  27 #include "mi/mi-common.h"
  28 #include "target.h"
  29 #include "valprint.h"
  30
  31 /* An instance of this type is used to represent a fork or vfork
  32    catchpoint.  A breakpoint is really of this type iff its ops pointer points
  33    to CATCH_FORK_BREAKPOINT_OPS.  */
  34
  35 struct fork_catchpoint : public breakpoint
  36 {
  37   fork_catchpoint (struct gdbarch *gdbarch, bool is_vfork_)
  38     : breakpoint (gdbarch, bp_catchpoint),
  39       is_vfork (is_vfork_)
  40   {
  41   }
  42
  43   int insert_location (struct bp_location *) override;
  44   int remove_location (struct bp_location *,
  45                        enum remove_bp_reason reason) override;
  46   int breakpoint_hit (const struct bp_location *bl,
  47                       const address_space *aspace,
  48                       CORE_ADDR bp_addr,
  49                       const target_waitstatus &ws) override;
  50   enum print_stop_action print_it (const bpstat *bs) const override;
  51   bool print_one (bp_location **) const override;
  52   void print_mention () const override;
  53   void print_recreate (struct ui_file *fp) const override;
  54
  55   /* True if the breakpoint is for vfork, false for fork.  */
  56   bool is_vfork;
  57
  58   /* Process id of a child process whose forking triggered this
  59      catchpoint.  This field is only valid immediately after this
  60      catchpoint has triggered.  */
  61   ptid_t forked_inferior_pid = null_ptid;
  62 };
  63
  64 /* Implement the "insert" method for fork catchpoints.  */
  65
  66 int
  67 fork_catchpoint::insert_location (struct bp_location *bl)
  68 {
  69   if (is_vfork)
  70     return target_insert_vfork_catchpoint (inferior_ptid.pid ());
  71   else
  72     return target_insert_fork_catchpoint (inferior_ptid.pid ());
  73 }
  74
  75 /* Implement the "remove" method for fork catchpoints.  */
  76
  77 int
  78 fork_catchpoint::remove_location (struct bp_location *bl,
  79                                   enum remove_bp_reason reason)
  80 {
  81   if (is_vfork)
  82     return target_remove_vfork_catchpoint (inferior_ptid.pid ());
  83   else
  84     return target_remove_fork_catchpoint (inferior_ptid.pid ());
  85 }
  86
  87 /* Implement the "breakpoint_hit" method for fork catchpoints.  */
  88
  89 int
  90 fork_catchpoint::breakpoint_hit (const struct bp_location *bl,
  91                                  const address_space *aspace,
  92                                  CORE_ADDR bp_addr,
  93                                  const target_waitstatus &ws)
  94 {
  95   if (ws.kind () != (is_vfork
  96                      ? TARGET_WAITKIND_VFORKED
  97                      : TARGET_WAITKIND_FORKED))
  98     return 0;
  99
 100   forked_inferior_pid = ws.child_ptid ();
 101   return 1;
 102 }
 103
 104 /* Implement the "print_it" method for fork catchpoints.  */
 105
 106 enum print_stop_action
 107 fork_catchpoint::print_it (const bpstat *bs) const
 108 {
 109   struct ui_out *uiout = current_uiout;
 110
 111   annotate_catchpoint (number);
 112   maybe_print_thread_hit_breakpoint (uiout);
 113   if (disposition == disp_del)
 114     uiout->text ("Temporary catchpoint ");
 115   else
 116     uiout->text ("Catchpoint ");
 117   if (uiout->is_mi_like_p ())
 118     {
 119       uiout->field_string ("reason",
 120                            async_reason_lookup (is_vfork
 121                                                 ? EXEC_ASYNC_VFORK
 122                                                 : EXEC_ASYNC_FORK));
 123       uiout->field_string ("disp", bpdisp_text (disposition));
 124     }
 125   uiout->field_signed ("bkptno", number);
 126   if (is_vfork)
 127     uiout->text (" (vforked process ");
 128   else
 129     uiout->text (" (forked process ");
 130   uiout->field_signed ("newpid", forked_inferior_pid.pid ());
 131   uiout->text ("), ");
 132   return PRINT_SRC_AND_LOC;
 133 }
 134
 135 /* Implement the "print_one" method for fork catchpoints.  */
 136
 137 bool
 138 fork_catchpoint::print_one (bp_location **last_loc) const
 139 {
 140   struct value_print_options opts;
 141   struct ui_out *uiout = current_uiout;
 142
 143   get_user_print_options (&opts);
 144
 145   /* Field 4, the address, is omitted (which makes the columns not
 146      line up too nicely with the headers, but the effect is relatively
 147      readable).  */
 148   if (opts.addressprint)
 149     uiout->field_skip ("addr");
 150   annotate_field (5);
 151   const char *name = is_vfork ? "vfork" : "fork";
 152   uiout->text (name);
 153   if (forked_inferior_pid != null_ptid)
 154     {
 155       uiout->text (", process ");
 156       uiout->field_signed ("what", forked_inferior_pid.pid ());
 157       uiout->spaces (1);
 158     }
 159
 160   if (uiout->is_mi_like_p ())
 161     uiout->field_string ("catch-type", name);
 162
 163   return true;
 164 }
 165
 166 /* Implement the "print_mention" method for fork catchpoints.  */
 167
 168 void
 169 fork_catchpoint::print_mention () const
 170 {
 171   gdb_printf (_("Catchpoint %d (%s)"), number,
 172               is_vfork ? "vfork" : "fork");
 173 }
 174
 175 /* Implement the "print_recreate" method for fork catchpoints.  */
 176
 177 void
 178 fork_catchpoint::print_recreate (struct ui_file *fp) const
 179 {
 180   gdb_printf (fp, "catch %s", is_vfork ? "vfork" : "fork");
 181   print_recreate_thread (fp);
 182 }
 183
 184 static void
 185 create_fork_vfork_event_catchpoint (struct gdbarch *gdbarch,
 186                                     bool temp, const char *cond_string,
 187                                     bool is_vfork)
 188 {
 189   std::unique_ptr<fork_catchpoint> c (new fork_catchpoint (gdbarch,
 190                                                            is_vfork));
 191
 192   init_catchpoint (c.get (), gdbarch, temp, cond_string);
 193
 194   install_breakpoint (0, std::move (c), 1);
 195 }
 196
 197 enum catch_fork_kind
 198 {
 199   catch_fork_temporary, catch_vfork_temporary,
 200   catch_fork_permanent, catch_vfork_permanent
 201 };
 202
 203 static void
 204 catch_fork_command_1 (const char *arg, int from_tty,
 205                       struct cmd_list_element *command)
 206 {
 207   struct gdbarch *gdbarch = get_current_arch ();
 208   const char *cond_string = NULL;
 209   catch_fork_kind fork_kind;
 210
 211   fork_kind = (catch_fork_kind) (uintptr_t) command->context ();
 212   bool temp = (fork_kind == catch_fork_temporary
 213                || fork_kind == catch_vfork_temporary);
 214
 215   if (!arg)
 216     arg = "";
 217   arg = skip_spaces (arg);
 218
 219   /* The allowed syntax is:
 220      catch [v]fork
 221      catch [v]fork if <cond>
 222
 223      First, check if there's an if clause.  */
 224   cond_string = ep_parse_optional_if_clause (&arg);
 225
 226   if ((*arg != '\0') && !isspace (*arg))
 227     error (_("Junk at end of arguments."));
 228
 229   /* If this target supports it, create a fork or vfork catchpoint
 230      and enable reporting of such events.  */
 231   switch (fork_kind)
 232     {
 233     case catch_fork_temporary:
 234     case catch_fork_permanent:
 235       create_fork_vfork_event_catchpoint (gdbarch, temp, cond_string, false);
 236       break;
 237     case catch_vfork_temporary:
 238     case catch_vfork_permanent:
 239       create_fork_vfork_event_catchpoint (gdbarch, temp, cond_string, true);
 240       break;
 241     default:
 242       error (_("unsupported or unknown fork kind; cannot catch it"));
 243       break;
 244     }
 245 }
 246
 247 void _initialize_break_catch_fork ();
 248 void
 249 _initialize_break_catch_fork ()
 250 {
 251   add_catch_command ("fork", _("Catch calls to fork."),
 252                      catch_fork_command_1,
 253                      NULL,
 254                      (void *) (uintptr_t) catch_fork_permanent,
 255                      (void *) (uintptr_t) catch_fork_temporary);
 256   add_catch_command ("vfork", _("Catch calls to vfork."),
 257                      catch_fork_command_1,
 258                      NULL,
 259                      (void *) (uintptr_t) catch_vfork_permanent,
 260                      (void *) (uintptr_t) catch_vfork_temporary);
 261 }