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   /* True if the breakpoint is for vfork, false for fork.  */
  38   bool is_vfork;
  39
  40   /* Process id of a child process whose forking triggered this
  41      catchpoint.  This field is only valid immediately after this
  42      catchpoint has triggered.  */
  43   ptid_t forked_inferior_pid;
  44 };
  45
  46 /* Implement the "insert" breakpoint_ops method for fork
  47    catchpoints.  */
  48
  49 static int
  50 insert_catch_fork (struct bp_location *bl)
  51 {
  52   struct fork_catchpoint *c = (struct fork_catchpoint *) bl->owner;
  53
  54   if (c->is_vfork)
  55     return target_insert_vfork_catchpoint (inferior_ptid.pid ());
  56   else
  57     return target_insert_fork_catchpoint (inferior_ptid.pid ());
  58 }
  59
  60 /* Implement the "remove" breakpoint_ops method for fork
  61    catchpoints.  */
  62
  63 static int
  64 remove_catch_fork (struct bp_location *bl, enum remove_bp_reason reason)
  65 {
  66   struct fork_catchpoint *c = (struct fork_catchpoint *) bl->owner;
  67
  68   if (c->is_vfork)
  69     return target_remove_vfork_catchpoint (inferior_ptid.pid ());
  70   else
  71     return target_remove_fork_catchpoint (inferior_ptid.pid ());
  72 }
  73
  74 /* Implement the "breakpoint_hit" breakpoint_ops method for fork
  75    catchpoints.  */
  76
  77 static int
  78 breakpoint_hit_catch_fork (const struct bp_location *bl,
  79                            const address_space *aspace, CORE_ADDR bp_addr,
  80                            const target_waitstatus &ws)
  81 {
  82   struct fork_catchpoint *c = (struct fork_catchpoint *) bl->owner;
  83
  84   if (ws.kind () != (c->is_vfork
  85                      ? TARGET_WAITKIND_VFORKED
  86                      : TARGET_WAITKIND_FORKED))
  87     return 0;
  88
  89   c->forked_inferior_pid = ws.child_ptid ();
  90   return 1;
  91 }
  92
  93 /* Implement the "print_it" breakpoint_ops method for fork
  94    catchpoints.  */
  95
  96 static enum print_stop_action
  97 print_it_catch_fork (bpstat *bs)
  98 {
  99   struct ui_out *uiout = current_uiout;
 100   struct breakpoint *b = bs->breakpoint_at;
 101   struct fork_catchpoint *c = (struct fork_catchpoint *) bs->breakpoint_at;
 102
 103   annotate_catchpoint (b->number);
 104   maybe_print_thread_hit_breakpoint (uiout);
 105   if (b->disposition == disp_del)
 106     uiout->text ("Temporary catchpoint ");
 107   else
 108     uiout->text ("Catchpoint ");
 109   if (uiout->is_mi_like_p ())
 110     {
 111       uiout->field_string ("reason",
 112                            async_reason_lookup (c->is_vfork
 113                                                 ? EXEC_ASYNC_VFORK
 114                                                 : EXEC_ASYNC_FORK));
 115       uiout->field_string ("disp", bpdisp_text (b->disposition));
 116     }
 117   uiout->field_signed ("bkptno", b->number);
 118   if (c->is_vfork)
 119     uiout->text (" (vforked process ");
 120   else
 121     uiout->text (" (forked process ");
 122   uiout->field_signed ("newpid", c->forked_inferior_pid.pid ());
 123   uiout->text ("), ");
 124   return PRINT_SRC_AND_LOC;
 125 }
 126
 127 /* Implement the "print_one" breakpoint_ops method for fork
 128    catchpoints.  */
 129
 130 static void
 131 print_one_catch_fork (struct breakpoint *b, struct bp_location **last_loc)
 132 {
 133   struct fork_catchpoint *c = (struct fork_catchpoint *) b;
 134   struct value_print_options opts;
 135   struct ui_out *uiout = current_uiout;
 136
 137   get_user_print_options (&opts);
 138
 139   /* Field 4, the address, is omitted (which makes the columns not
 140      line up too nicely with the headers, but the effect is relatively
 141      readable).  */
 142   if (opts.addressprint)
 143     uiout->field_skip ("addr");
 144   annotate_field (5);
 145   const char *name = c->is_vfork ? "vfork" : "fork";
 146   uiout->text (name);
 147   if (c->forked_inferior_pid != null_ptid)
 148     {
 149       uiout->text (", process ");
 150       uiout->field_signed ("what", c->forked_inferior_pid.pid ());
 151       uiout->spaces (1);
 152     }
 153
 154   if (uiout->is_mi_like_p ())
 155     uiout->field_string ("catch-type", name);
 156 }
 157
 158 /* Implement the "print_mention" breakpoint_ops method for fork
 159    catchpoints.  */
 160
 161 static void
 162 print_mention_catch_fork (struct breakpoint *b)
 163 {
 164   struct fork_catchpoint *c = (struct fork_catchpoint *) b;
 165   gdb_printf (_("Catchpoint %d (%s)"), c->number,
 166               c->is_vfork ? "vfork" : "fork");
 167 }
 168
 169 /* Implement the "print_recreate" breakpoint_ops method for fork
 170    catchpoints.  */
 171
 172 static void
 173 print_recreate_catch_fork (struct breakpoint *b, struct ui_file *fp)
 174 {
 175   struct fork_catchpoint *c = (struct fork_catchpoint *) b;
 176   gdb_printf (fp, "catch %s",
 177               c->is_vfork ? "vfork" : "fork");
 178   print_recreate_thread (b, fp);
 179 }
 180
 181 /* The breakpoint_ops structure to be used in fork catchpoints.  */
 182
 183 static struct breakpoint_ops catch_fork_breakpoint_ops;
 184
 185 static void
 186 create_fork_vfork_event_catchpoint (struct gdbarch *gdbarch,
 187                                     bool temp, const char *cond_string,
 188                                     bool is_vfork)
 189 {
 190   std::unique_ptr<fork_catchpoint> c (new fork_catchpoint ());
 191
 192   init_catchpoint (c.get (), gdbarch, temp, cond_string,
 193                    &catch_fork_breakpoint_ops);
 194   c->is_vfork = is_vfork;
 195   c->forked_inferior_pid = null_ptid;
 196
 197   install_breakpoint (0, std::move (c), 1);
 198 }
 199
 200 typedef enum
 201 {
 202   catch_fork_temporary, catch_vfork_temporary,
 203   catch_fork_permanent, catch_vfork_permanent
 204 }
 205 catch_fork_kind;
 206
 207 static void
 208 catch_fork_command_1 (const char *arg, int from_tty,
 209                       struct cmd_list_element *command)
 210 {
 211   struct gdbarch *gdbarch = get_current_arch ();
 212   const char *cond_string = NULL;
 213   catch_fork_kind fork_kind;
 214
 215   fork_kind = (catch_fork_kind) (uintptr_t) command->context ();
 216   bool temp = (fork_kind == catch_fork_temporary
 217                || fork_kind == catch_vfork_temporary);
 218
 219   if (!arg)
 220     arg = "";
 221   arg = skip_spaces (arg);
 222
 223   /* The allowed syntax is:
 224      catch [v]fork
 225      catch [v]fork if <cond>
 226
 227      First, check if there's an if clause.  */
 228   cond_string = ep_parse_optional_if_clause (&arg);
 229
 230   if ((*arg != '\0') && !isspace (*arg))
 231     error (_("Junk at end of arguments."));
 232
 233   /* If this target supports it, create a fork or vfork catchpoint
 234      and enable reporting of such events.  */
 235   switch (fork_kind)
 236     {
 237     case catch_fork_temporary:
 238     case catch_fork_permanent:
 239       create_fork_vfork_event_catchpoint (gdbarch, temp, cond_string, false);
 240       break;
 241     case catch_vfork_temporary:
 242     case catch_vfork_permanent:
 243       create_fork_vfork_event_catchpoint (gdbarch, temp, cond_string, true);
 244       break;
 245     default:
 246       error (_("unsupported or unknown fork kind; cannot catch it"));
 247       break;
 248     }
 249 }
 250
 251 static void
 252 initialize_ops ()
 253 {
 254   struct breakpoint_ops *ops;
 255
 256   initialize_breakpoint_ops ();
 257
 258   /* Fork catchpoints.  */
 259   ops = &catch_fork_breakpoint_ops;
 260   *ops = base_breakpoint_ops;
 261   ops->insert_location = insert_catch_fork;
 262   ops->remove_location = remove_catch_fork;
 263   ops->breakpoint_hit = breakpoint_hit_catch_fork;
 264   ops->print_it = print_it_catch_fork;
 265   ops->print_one = print_one_catch_fork;
 266   ops->print_mention = print_mention_catch_fork;
 267   ops->print_recreate = print_recreate_catch_fork;
 268 }
 269
 270 void _initialize_break_catch_fork ();
 271 void
 272 _initialize_break_catch_fork ()
 273 {
 274   initialize_ops ();
 275
 276   add_catch_command ("fork", _("Catch calls to fork."),
 277                      catch_fork_command_1,
 278                      NULL,
 279                      (void *) (uintptr_t) catch_fork_permanent,
 280                      (void *) (uintptr_t) catch_fork_temporary);
 281   add_catch_command ("vfork", _("Catch calls to vfork."),
 282                      catch_fork_command_1,
 283                      NULL,
 284                      (void *) (uintptr_t) catch_vfork_permanent,
 285                      (void *) (uintptr_t) catch_vfork_temporary);
 286 }