Move "catch fork" to a new file

The "catch fork" code is reasonably self-contained, and so this patch
moves it out of breakpoint.c (the second largest source file in gdb)
and into a new file, break-catch-fork.c.

1 files changed, 286 insertions, 0 deletions

diff --git a/gdb/break-catch-fork.c b/gdb/break-catch-fork.c
new file mode 100644
index 0000000..af44a9f
--- /dev/null
+++ b/gdb/break-catch-fork.c
@@ -0,0 +1,286 @@
+/* Everything about vfork catchpoints, for GDB.
+
+   Copyright (C) 1986-2022 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "defs.h"
+
+#include "annotate.h"
+#include "arch-utils.h"
+#include "breakpoint.h"
+#include "cli/cli-decode.h"
+#include "inferior.h"
+#include "mi/mi-common.h"
+#include "target.h"
+#include "valprint.h"
+
+/* An instance of this type is used to represent a fork or vfork
+   catchpoint.  A breakpoint is really of this type iff its ops pointer points
+   to CATCH_FORK_BREAKPOINT_OPS.  */
+
+struct fork_catchpoint : public breakpoint
+{
+  /* True if the breakpoint is for vfork, false for fork.  */
+  bool is_vfork;
+
+  /* Process id of a child process whose forking triggered this
+     catchpoint.  This field is only valid immediately after this
+     catchpoint has triggered.  */
+  ptid_t forked_inferior_pid;
+};
+
+/* Implement the "insert" breakpoint_ops method for fork
+   catchpoints.  */
+
+static int
+insert_catch_fork (struct bp_location *bl)
+{
+  struct fork_catchpoint *c = (struct fork_catchpoint *) bl->owner;
+
+  if (c->is_vfork)
+    return target_insert_vfork_catchpoint (inferior_ptid.pid ());
+  else
+    return target_insert_fork_catchpoint (inferior_ptid.pid ());
+}
+
+/* Implement the "remove" breakpoint_ops method for fork
+   catchpoints.  */
+
+static int
+remove_catch_fork (struct bp_location *bl, enum remove_bp_reason reason)
+{
+  struct fork_catchpoint *c = (struct fork_catchpoint *) bl->owner;
+
+  if (c->is_vfork)
+    return target_remove_vfork_catchpoint (inferior_ptid.pid ());
+  else
+    return target_remove_fork_catchpoint (inferior_ptid.pid ());
+}
+
+/* Implement the "breakpoint_hit" breakpoint_ops method for fork
+   catchpoints.  */
+
+static int
+breakpoint_hit_catch_fork (const struct bp_location *bl,
+			   const address_space *aspace, CORE_ADDR bp_addr,
+			   const target_waitstatus &ws)
+{
+  struct fork_catchpoint *c = (struct fork_catchpoint *) bl->owner;
+
+  if (ws.kind () != (c->is_vfork
+		     ? TARGET_WAITKIND_VFORKED
+		     : TARGET_WAITKIND_FORKED))
+    return 0;
+
+  c->forked_inferior_pid = ws.child_ptid ();
+  return 1;
+}
+
+/* Implement the "print_it" breakpoint_ops method for fork
+   catchpoints.  */
+
+static enum print_stop_action
+print_it_catch_fork (bpstat *bs)
+{
+  struct ui_out *uiout = current_uiout;
+  struct breakpoint *b = bs->breakpoint_at;
+  struct fork_catchpoint *c = (struct fork_catchpoint *) bs->breakpoint_at;
+
+  annotate_catchpoint (b->number);
+  maybe_print_thread_hit_breakpoint (uiout);
+  if (b->disposition == disp_del)
+    uiout->text ("Temporary catchpoint ");
+  else
+    uiout->text ("Catchpoint ");
+  if (uiout->is_mi_like_p ())
+    {
+      uiout->field_string ("reason",
+			   async_reason_lookup (c->is_vfork
+						? EXEC_ASYNC_VFORK
+						: EXEC_ASYNC_FORK));
+      uiout->field_string ("disp", bpdisp_text (b->disposition));
+    }
+  uiout->field_signed ("bkptno", b->number);
+  if (c->is_vfork)
+    uiout->text (" (vforked process ");
+  else
+    uiout->text (" (forked process ");
+  uiout->field_signed ("newpid", c->forked_inferior_pid.pid ());
+  uiout->text ("), ");
+  return PRINT_SRC_AND_LOC;
+}
+
+/* Implement the "print_one" breakpoint_ops method for fork
+   catchpoints.  */
+
+static void
+print_one_catch_fork (struct breakpoint *b, struct bp_location **last_loc)
+{
+  struct fork_catchpoint *c = (struct fork_catchpoint *) b;
+  struct value_print_options opts;
+  struct ui_out *uiout = current_uiout;
+
+  get_user_print_options (&opts);
+
+  /* Field 4, the address, is omitted (which makes the columns not
+     line up too nicely with the headers, but the effect is relatively
+     readable).  */
+  if (opts.addressprint)
+    uiout->field_skip ("addr");
+  annotate_field (5);
+  const char *name = c->is_vfork ? "vfork" : "fork";
+  uiout->text (name);
+  if (c->forked_inferior_pid != null_ptid)
+    {
+      uiout->text (", process ");
+      uiout->field_signed ("what", c->forked_inferior_pid.pid ());
+      uiout->spaces (1);
+    }
+
+  if (uiout->is_mi_like_p ())
+    uiout->field_string ("catch-type", name);
+}
+
+/* Implement the "print_mention" breakpoint_ops method for fork
+   catchpoints.  */
+
+static void
+print_mention_catch_fork (struct breakpoint *b)
+{
+  struct fork_catchpoint *c = (struct fork_catchpoint *) b;
+  printf_filtered (_("Catchpoint %d (%s)"), c->number,
+		   c->is_vfork ? "vfork" : "fork");
+}
+
+/* Implement the "print_recreate" breakpoint_ops method for fork
+   catchpoints.  */
+
+static void
+print_recreate_catch_fork (struct breakpoint *b, struct ui_file *fp)
+{
+  struct fork_catchpoint *c = (struct fork_catchpoint *) b;
+  fprintf_unfiltered (fp, "catch %s",
+		      c->is_vfork ? "vfork" : "fork");
+  print_recreate_thread (b, fp);
+}
+
+/* The breakpoint_ops structure to be used in fork catchpoints.  */
+
+static struct breakpoint_ops catch_fork_breakpoint_ops;
+
+static void
+create_fork_vfork_event_catchpoint (struct gdbarch *gdbarch,
+				    bool temp, const char *cond_string,
+				    bool is_vfork)
+{
+  std::unique_ptr<fork_catchpoint> c (new fork_catchpoint ());
+
+  init_catchpoint (c.get (), gdbarch, temp, cond_string,
+		   &catch_fork_breakpoint_ops);
+  c->is_vfork = is_vfork;
+  c->forked_inferior_pid = null_ptid;
+
+  install_breakpoint (0, std::move (c), 1);
+}
+
+typedef enum
+{
+  catch_fork_temporary, catch_vfork_temporary,
+  catch_fork_permanent, catch_vfork_permanent
+}
+catch_fork_kind;
+
+static void
+catch_fork_command_1 (const char *arg, int from_tty,
+		      struct cmd_list_element *command)
+{
+  struct gdbarch *gdbarch = get_current_arch ();
+  const char *cond_string = NULL;
+  catch_fork_kind fork_kind;
+
+  fork_kind = (catch_fork_kind) (uintptr_t) command->context ();
+  bool temp = (fork_kind == catch_fork_temporary
+	       || fork_kind == catch_vfork_temporary);
+
+  if (!arg)
+    arg = "";
+  arg = skip_spaces (arg);
+
+  /* The allowed syntax is:
+     catch [v]fork
+     catch [v]fork if <cond>
+
+     First, check if there's an if clause.  */
+  cond_string = ep_parse_optional_if_clause (&arg);
+
+  if ((*arg != '\0') && !isspace (*arg))
+    error (_("Junk at end of arguments."));
+
+  /* If this target supports it, create a fork or vfork catchpoint
+     and enable reporting of such events.  */
+  switch (fork_kind)
+    {
+    case catch_fork_temporary:
+    case catch_fork_permanent:
+      create_fork_vfork_event_catchpoint (gdbarch, temp, cond_string, false);
+      break;
+    case catch_vfork_temporary:
+    case catch_vfork_permanent:
+      create_fork_vfork_event_catchpoint (gdbarch, temp, cond_string, true);
+      break;
+    default:
+      error (_("unsupported or unknown fork kind; cannot catch it"));
+      break;
+    }
+}
+
+static void
+initialize_ops ()
+{
+  struct breakpoint_ops *ops;
+
+  initialize_breakpoint_ops ();
+
+  /* Fork catchpoints.  */
+  ops = &catch_fork_breakpoint_ops;
+  *ops = base_breakpoint_ops;
+  ops->insert_location = insert_catch_fork;
+  ops->remove_location = remove_catch_fork;
+  ops->breakpoint_hit = breakpoint_hit_catch_fork;
+  ops->print_it = print_it_catch_fork;
+  ops->print_one = print_one_catch_fork;
+  ops->print_mention = print_mention_catch_fork;
+  ops->print_recreate = print_recreate_catch_fork;
+}
+
+void _initialize_break_catch_fork ();
+void
+_initialize_break_catch_fork ()
+{
+  initialize_ops ();
+
+  add_catch_command ("fork", _("Catch calls to fork."),
+		     catch_fork_command_1,
+		     NULL,
+		     (void *) (uintptr_t) catch_fork_permanent,
+		     (void *) (uintptr_t) catch_fork_temporary);
+  add_catch_command ("vfork", _("Catch calls to vfork."),
+		     catch_fork_command_1,
+		     NULL,
+		     (void *) (uintptr_t) catch_vfork_permanent,
+		     (void *) (uintptr_t) catch_vfork_temporary);
+}