Refactor native follow-fork.

This patch reorganizes the code that implements follow-fork and
detach-on-fork in preparation for implementation of those features for the
extended-remote target.  The function linux-nat.c:linux_child_follow_fork
contained target-independent code mixed in with target-dependent code.  The
target-independent pieces need to be accessible for the host-side
implementation of follow-fork for extended-remote Linux targets.

The changes are fairly mechanical.  A new routine, follow_fork_inferior,
is implemented in infrun.c, containing those parts of
linux_child_follow_fork that manage inferiors and the inferior list.  The
parts of linux_child_follow_fork that deal with LWPs and target-specifics
were left in-place.  Although the order of some operations was changed, the
resulting functionality was not.

Modifications were made to the other native target follow-fork functions,
inf_ttrace_follow_fork and inf_ptrace_follow_fork, that should allow them
to work with follow_fork_inferior.  Some other adjustments were necessary
in inf-ttrace.c.  The changes to inf-ttrace.c and inf-ptrace.c were not
tested.

gdb/ChangeLog:

	* inf-ptrace.c (inf_ptrace_follow_fork): Remove target-independent
	code so as to work with follow_fork_inferior.
	* inf-ttrace.c (inf_ttrace_follow_fork): Ditto.
	(inf_ttrace_create_inferior): Remove reference to
	inf_ttrace_vfork_ppid.
	(inf_ttrace_attach): Ditto.
	(inf_ttrace_detach): Ditto.
	(inf_ttrace_kill): Use current_inferior instead of
	inf_ttrace_vfork_ppid.
	(inf_ttrace_wait): Eliminate use of inf_ttrace_vfork_ppid, report
	TARGET_WAITKIND_VFORK_DONE event, delete HACK that switched the
	inferior away from the parent.
	* infrun.c (follow_fork): Call follow_fork_inferior instead of
	target_follow_fork.
	(follow_fork_inferior): New function.
	(follow_inferior_reset_breakpoints): Make function static.
	* infrun.h (follow_inferior_reset_breakpoints): Remove declaration.
	* linux-nat.c (linux_child_follow_fork): Move target-independent
	code to infrun.c:follow_fork_inferior.

1 files changed, 6 insertions, 42 deletions

diff --git a/gdb/inf-ptrace.c b/gdb/inf-ptrace.c
index dd71b3abc3..6eb8080242 100644
--- a/gdb/inf-ptrace.c
+++ b/gdb/inf-ptrace.c
@@ -36,57 +36,21 @@
 
 #ifdef PT_GET_PROCESS_STATE
 
+/* Target hook for follow_fork.  On entry and at return inferior_ptid is
+   the ptid of the followed inferior.  */
+
 static int
 inf_ptrace_follow_fork (struct target_ops *ops, int follow_child,
 			int detach_fork)
 {
-  pid_t pid, fpid;
-  ptrace_state_t pe;
-
-  pid = ptid_get_pid (inferior_ptid);
-
-  if (ptrace (PT_GET_PROCESS_STATE, pid,
-	       (PTRACE_TYPE_ARG3)&pe, sizeof pe) == -1)
-    perror_with_name (("ptrace"));
-
-  gdb_assert (pe.pe_report_event == PTRACE_FORK);
-  fpid = pe.pe_other_pid;
-
-  if (follow_child)
+  if (!follow_child)
     {
-      struct inferior *parent_inf, *child_inf;
-      struct thread_info *tp;
-
-      parent_inf = find_inferior_pid (pid);
-
-      /* Add the child.  */
-      child_inf = add_inferior (fpid);
-      child_inf->attach_flag = parent_inf->attach_flag;
-      copy_terminal_info (child_inf, parent_inf);
-      child_inf->pspace = parent_inf->pspace;
-      child_inf->aspace = parent_inf->aspace;
+      pid_t child_pid = inferior_thread->pending_follow.value.related_pid;
 
-      /* Before detaching from the parent, remove all breakpoints from
-	 it.  */
-      remove_breakpoints ();
-
-      if (ptrace (PT_DETACH, pid, (PTRACE_TYPE_ARG3)1, 0) == -1)
-	perror_with_name (("ptrace"));
-
-      /* Switch inferior_ptid out of the parent's way.  */
-      inferior_ptid = pid_to_ptid (fpid);
-
-      /* Delete the parent.  */
-      detach_inferior (pid);
-
-      add_thread_silent (inferior_ptid);
-    }
-  else
-    {
       /* Breakpoints have already been detached from the child by
 	 infrun.c.  */
 
-      if (ptrace (PT_DETACH, fpid, (PTRACE_TYPE_ARG3)1, 0) == -1)
+      if (ptrace (PT_DETACH, child_pid, (PTRACE_TYPE_ARG3)1, 0) == -1)
 	perror_with_name (("ptrace"));
     }