Add support for following forks. Backported from the to-be released gdb 6.4.

Only works on amd64, i386, m88k, mips64, sparc, sparc64 and vax for now.

1 files changed, 450 insertions, 355 deletions

diff --git a/gnu/usr.bin/binutils/gdb/inf-ptrace.c b/gnu/usr.bin/binutils/gdb/inf-ptrace.c
index 74faf5788b6..f2f6d276dd2 100644
--- a/gnu/usr.bin/binutils/gdb/inf-ptrace.c
+++ b/gnu/usr.bin/binutils/gdb/inf-ptrace.c
@@ -1,7 +1,8 @@
-/* Low level Unix child interface to ptrace, for GDB when running under Unix.
+/* Low-level child interface to ptrace.
 
    Copyright 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996,
-   1998, 1999, 2000, 2001, 2002, 2004 Free Software Foundation, Inc.
+   1998, 1999, 2000, 2001, 2002, 2004, 2005
+   Free Software Foundation, Inc.
 
    This file is part of GDB.
 
@@ -21,188 +22,195 @@
    Boston, MA 02111-1307, USA.  */
 
 #include "defs.h"
-#include "observer.h"
-#include "gdb_ptrace.h"
-#include "inflow.h"
-#include "inferior.h"
-#include "regcache.h"
 #include "command.h"
+#include "inferior.h"
+#include "inflow.h"
 #include "gdbcore.h"
-#include "inf-child.h"
-#include "gdbcmd.h"
-#include "gdb_string.h"
+#include "observer.h"
+#include "regcache.h"
 
+#include "gdb_assert.h"
+#include "gdb_string.h"
+#include "gdb_ptrace.h"
 #include "gdb_wait.h"
 #include <signal.h>
 
-/* HACK: Save the ptrace ops returned by ptrace_target.  */
+#include "inf-child.h"
+
+/* HACK: Save the ptrace ops returned by inf_ptrace_target.  */
 static struct target_ops *ptrace_ops_hack;
+
 
-static void
-inf_ptrace_kill_inferior (void)
+#ifdef PT_GET_PROCESS_STATE
+
+static int
+inf_ptrace_follow_fork (int follow_child)
 {
-  int status;
-  int pid = PIDGET (inferior_ptid);
+  pid_t pid, fpid;
+  ptrace_state_t pe;
 
-  if (pid == 0)
-    return;
+  /* FIXME: kettenis/20050720: This stuff should really be passed as
+     an argument by our caller.  */
+  {
+    ptid_t ptid;
+    struct target_waitstatus status;
 
-  /* This once used to call "kill" to kill the inferior just in case
-     the inferior was still running.  As others have noted in the past
-     (kingdon) there shouldn't be any way to get here if the inferior
-     is still running -- else there's a major problem elsewere in gdb
-     and it needs to be fixed.
+    get_last_target_status (&ptid, &status);
+    gdb_assert (status.kind == TARGET_WAITKIND_FORKED);
 
-     The kill call causes problems under hpux10, so it's been removed;
-     if this causes problems we'll deal with them as they arise.  */
-  ptrace (PT_KILL, pid, (PTRACE_TYPE_ARG3) 0, 0);
-  wait (&status);
-  target_mourn_inferior ();
-}
+    pid = ptid_get_pid (ptid);
+  }
 
-/* Resume execution of the inferior process.  If STEP is nonzero,
-   single-step it.  If SIGNAL is nonzero, give it that signal.  */
+  if (ptrace (PT_GET_PROCESS_STATE, pid,
+	       (PTRACE_TYPE_ARG3)&pe, sizeof pe) == -1)
+    perror_with_name (("ptrace"));
 
-static void
-inf_ptrace_resume (ptid_t ptid, int step, enum target_signal signal)
-{
-  int request = PT_CONTINUE;
-  int pid = PIDGET (ptid);
+  gdb_assert (pe.pe_report_event == PTRACE_FORK);
+  fpid = pe.pe_other_pid;
 
-  if (pid == -1)
-    /* Resume all threads.  */
-    /* I think this only gets used in the non-threaded case, where
-       "resume all threads" and "resume inferior_ptid" are the
-       same.  */
-    pid = PIDGET (inferior_ptid);
+  if (follow_child)
+    {
+      inferior_ptid = pid_to_ptid (fpid);
+      detach_breakpoints (pid);
 
-  if (step)
+      /* Reset breakpoints in the child as appropriate.  */
+      follow_inferior_reset_breakpoints ();
+
+      if (ptrace (PT_DETACH, pid, (PTRACE_TYPE_ARG3)1, 0) == -1)
+	perror_with_name (("ptrace"));
+    }
+  else
     {
-      /* If this system does not support PT_STEP, a higher level
-         function will have called single_step() to transmute the step
-         request into a continue request (by setting breakpoints on
-         all possible successor instructions), so we don't have to
-         worry about that here.  */
-      request = PT_STEP;
+      inferior_ptid = pid_to_ptid (pid);
+      detach_breakpoints (fpid);
+
+      if (ptrace (PT_DETACH, fpid, (PTRACE_TYPE_ARG3)1, 0) == -1)
+	perror_with_name (("ptrace"));
     }
 
-  /* An address of (PTRACE_TYPE_ARG3)1 tells ptrace to continue from
-     where it was.  If GDB wanted it to start some other way, we have
-     already written a new PC value to the child.  */
-  errno = 0;
-  ptrace (request, pid, (PTRACE_TYPE_ARG3) 1, target_signal_to_host (signal));
-  if (errno != 0)
-    perror_with_name ("ptrace");
+  return 0;
 }
 
-/* Wait for child to do something.  Return pid of child, or -1 in case
-   of error; store status through argument pointer OURSTATUS.  */
+#endif /* PT_GET_PROCESS_STATE */
+
 
-static ptid_t
-inf_ptrace_wait (ptid_t ptid, struct target_waitstatus *ourstatus)
+/* Prepare to be traced.  */
+
+static void
+inf_ptrace_me (void)
 {
-  int save_errno;
-  int status;
-  char *execd_pathname = NULL;
-  int exit_status;
-  int related_pid;
-  int syscall_id;
-  enum target_waitkind kind;
-  int pid;
+  /* "Trace me, Dr. Memory!"  */
+  ptrace (PT_TRACE_ME, 0, (PTRACE_TYPE_ARG3)0, 0);
+}
 
-  do
-    {
-      set_sigint_trap ();	/* Causes SIGINT to be passed on to the
-				   attached process. */
-      set_sigio_trap ();
+/* Start tracing PID.  */
 
-      pid = wait (&status);
+static void
+inf_ptrace_him (int pid)
+{
+  push_target (ptrace_ops_hack);
 
-      save_errno = errno;
+  /* On some targets, there must be some explicit synchronization
+     between the parent and child processes after the debugger
+     forks, and before the child execs the debuggee program.  This
+     call basically gives permission for the child to exec.  */
 
-      clear_sigio_trap ();
+  target_acknowledge_created_inferior (pid);
 
-      clear_sigint_trap ();
+  /* START_INFERIOR_TRAPS_EXPECTED is defined in inferior.h, and will
+     be 1 or 2 depending on whether we're starting without or with a
+     shell.  */
+  startup_inferior (START_INFERIOR_TRAPS_EXPECTED);
 
-      if (pid == -1)
-	{
-	  if (save_errno == EINTR)
-	    continue;
+  /* On some targets, there must be some explicit actions taken after
+     the inferior has been started up.  */
+  target_post_startup_inferior (pid_to_ptid (pid));
+}
 
-	  fprintf_unfiltered (gdb_stderr,
-			      "Child process unexpectedly missing: %s.\n",
-			      safe_strerror (save_errno));
+/* Start a new inferior Unix child process.  EXEC_FILE is the file to
+   run, ALLARGS is a string containing the arguments to the program.
+   ENV is the environment vector to pass.  If FROM_TTY is non-zero, be
+   chatty about it.  */
 
-	  /* Claim it exited with unknown signal.  */
-	  ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
-	  ourstatus->value.sig = TARGET_SIGNAL_UNKNOWN;
-	  return pid_to_ptid (-1);
-	}
+static void
+inf_ptrace_create_inferior (char *exec_file, char *allargs, char **env,
+			    int from_tty)
+{
+  fork_inferior (exec_file, allargs, env, inf_ptrace_me, inf_ptrace_him,
+		 NULL, NULL);
 
-      /* Did it exit?
-       */
-      if (target_has_exited (pid, status, &exit_status))
-	{
-	  /* ??rehrauer: For now, ignore this. */
-	  continue;
-	}
+  /* We are at the first instruction we care about.  */
+  observer_notify_inferior_created (&current_target, from_tty);
 
-      if (!target_thread_alive (pid_to_ptid (pid)))
-	{
-	  ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
-	  return pid_to_ptid (pid);
-	}
-    }
-  while (pid != PIDGET (inferior_ptid));	/* Some other child died or stopped */
+  /* Pedal to the metal...  */
+  proceed ((CORE_ADDR) -1, TARGET_SIGNAL_0, 0);
+}
 
-  store_waitstatus (ourstatus, status);
-  return pid_to_ptid (pid);
+#ifdef PT_GET_PROCESS_STATE
+
+static void
+inf_ptrace_post_startup_inferior (ptid_t pid)
+{
+  ptrace_event_t pe;
+
+  /* Set the initial event mask.  */
+  memset (&pe, 0, sizeof pe);
+  pe.pe_set_event |= PTRACE_FORK;
+  if (ptrace (PT_SET_EVENT_MASK, ptid_get_pid (pid),
+	      (PTRACE_TYPE_ARG3)&pe, sizeof pe) == -1)
+    perror_with_name (("ptrace"));
 }
 
-/* Check to see if the given thread is alive.
+#endif
 
-   FIXME: Is kill() ever the right way to do this?  I doubt it, but
-   for now we're going to try and be compatable with the old thread
-   code.  */
+/* Clean up a rotting corpse of an inferior after it died.  */
 
-static int
-inf_ptrace_thread_alive (ptid_t ptid)
+static void
+inf_ptrace_mourn_inferior (void)
 {
-  pid_t pid = PIDGET (ptid);
+  int status;
 
-  return (kill (pid, 0) != -1);
+  /* Wait just one more time to collect the inferior's exit status.
+     Don not check whether this succeeds though, since we may be
+     dealing with a process that we attached to.  Such a process will
+     only report its exit status to its origional parent.  */
+  waitpid (ptid_get_pid (inferior_ptid), &status, 0);
+
+  unpush_target (ptrace_ops_hack);
+  generic_mourn_inferior ();
 }
 
-/* Attach to process PID, then initialize for debugging it.  */
+/* Attach to the process specified by ARGS.  If FROM_TTY is non-zero,
+   be chatty about it.  */
 
 static void
 inf_ptrace_attach (char *args, int from_tty)
 {
   char *exec_file;
-  int pid;
+  pid_t pid;
   char *dummy;
 
   if (!args)
-    error_no_arg ("process-id to attach");
+    error_no_arg (_("process-id to attach"));
 
   dummy = args;
   pid = strtol (args, &dummy, 0);
-  /* Some targets don't set errno on errors, grrr! */
+  /* Some targets don't set errno on errors, grrr!  */
   if (pid == 0 && args == dummy)
-    error ("Illegal process-id: %s\n", args);
+    error (_("Illegal process-id: %s."), args);
 
-  if (pid == getpid ())		/* Trying to masturbate? */
-    error ("I refuse to debug myself!");
+  if (pid == getpid ())		/* Trying to masturbate?  */
+    error (_("I refuse to debug myself!"));
 
   if (from_tty)
     {
-      exec_file = (char *) get_exec_file (0);
+      exec_file = get_exec_file (0);
 
       if (exec_file)
-	printf_unfiltered ("Attaching to program: %s, %s\n", exec_file,
+	printf_unfiltered (_("Attaching to program: %s, %s\n"), exec_file,
 			   target_pid_to_str (pid_to_ptid (pid)));
       else
-	printf_unfiltered ("Attaching to %s\n",
+	printf_unfiltered (_("Attaching to %s\n"),
 			   target_pid_to_str (pid_to_ptid (pid)));
 
       gdb_flush (gdb_stdout);
@@ -210,44 +218,54 @@ inf_ptrace_attach (char *args, int from_tty)
 
 #ifdef PT_ATTACH
   errno = 0;
-  ptrace (PT_ATTACH, pid, (PTRACE_TYPE_ARG3) 0, 0);
+  ptrace (PT_ATTACH, pid, (PTRACE_TYPE_ARG3)0, 0);
   if (errno != 0)
-    perror_with_name ("ptrace");
+    perror_with_name (("ptrace"));
   attach_flag = 1;
 #else
-  error ("This system does not support attaching to a process");
+  error (_("This system does not support attaching to a process"));
 #endif
 
   inferior_ptid = pid_to_ptid (pid);
   push_target (ptrace_ops_hack);
+
+  /* Do this first, before anything has had a chance to query the
+     inferior's symbol table or similar.  */
+  observer_notify_inferior_created (&current_target, from_tty);
 }
 
-static void
+#ifdef PT_GET_PROCESS_STATE
+
+void
 inf_ptrace_post_attach (int pid)
 {
-  /* This version of Unix doesn't require a meaningful "post attach"
-     operation by a debugger.  */
+  ptrace_event_t pe;
+
+  /* Set the initial event mask.  */
+  memset (&pe, 0, sizeof pe);
+  pe.pe_set_event |= PTRACE_FORK;
+  if (ptrace (PT_SET_EVENT_MASK, pid,
+	      (PTRACE_TYPE_ARG3)&pe, sizeof pe) == -1)
+    perror_with_name (("ptrace"));
 }
 
-/* Take a program previously attached to and detaches it.  The program
-   resumes execution and will no longer stop on signals, etc.  We'd
-   better not have left any breakpoints in the program or it'll die
-   when it hits one.  For this to work, it may be necessary for the
-   process to have been previously attached.  It *might* work if the
-   program was started via the normal ptrace (PTRACE_TRACEME).  */
+#endif
+
+/* Detach from the inferior, optionally passing it the signal
+   specified ARGS.  If FROM_TTY is non-zero, be chatty about it.  */
 
 static void
 inf_ptrace_detach (char *args, int from_tty)
 {
+  pid_t pid = ptid_get_pid (inferior_ptid);
   int sig = 0;
-  int pid = PIDGET (inferior_ptid);
 
   if (from_tty)
     {
       char *exec_file = get_exec_file (0);
       if (exec_file == 0)
 	exec_file = "";
-      printf_unfiltered ("Detaching from program: %s, %s\n", exec_file,
+      printf_unfiltered (_("Detaching from program: %s, %s\n"), exec_file,
 			 target_pid_to_str (pid_to_ptid (pid)));
       gdb_flush (gdb_stdout);
     }
@@ -255,228 +273,184 @@ inf_ptrace_detach (char *args, int from_tty)
     sig = atoi (args);
 
 #ifdef PT_DETACH
+  /* We'd better not have left any breakpoints in the program or it'll
+     die when it hits one.  Alsno note that this may only work if we
+     previously attached to the inferior.  It *might* work if we
+     started the process ourselves.  */
   errno = 0;
-  ptrace (PT_DETACH, pid, (PTRACE_TYPE_ARG3) 1, sig);
+  ptrace (PT_DETACH, pid, (PTRACE_TYPE_ARG3)1, sig);
   if (errno != 0)
-    perror_with_name ("ptrace");
+    perror_with_name (("ptrace"));
   attach_flag = 0;
 #else
-  error ("This system does not support detaching from a process");
+  error (_("This system does not support detaching from a process"));
 #endif
 
   inferior_ptid = null_ptid;
   unpush_target (ptrace_ops_hack);
 }
 
-/* Get ready to modify the registers array.  On machines which store
-   individual registers, this doesn't need to do anything.  On
-   machines which store all the registers in one fell swoop, this
-   makes sure that registers contains all the registers from the
-   program being debugged.  */
-
-static void
-inf_ptrace_prepare_to_store (void)
-{
-}
-
-/* Print status information about what we're accessing.  */
+/* Kill the inferior.  */
 
 static void
-inf_ptrace_files_info (struct target_ops *ignore)
+inf_ptrace_kill (void)
 {
-  printf_unfiltered ("\tUsing the running image of %s %s.\n",
-		     attach_flag ? "attached" : "child",
-		     target_pid_to_str (inferior_ptid));
-}
+  pid_t pid = ptid_get_pid (inferior_ptid);
+  int status;
 
-static void
-inf_ptrace_open (char *arg, int from_tty)
-{
-  error ("Use the \"run\" command to start a Unix child process.");
-}
+  if (pid == 0)
+    return;
 
-/* Stub function which causes the inferior that runs it, to be ptrace-able
-   by its parent process.  */
+  ptrace (PT_KILL, pid, (PTRACE_TYPE_ARG3)0, 0);
+  waitpid (pid, &status, 0);
 
-static void
-inf_ptrace_me (void)
-{
-  /* "Trace me, Dr. Memory!" */
-  ptrace (0, 0, (PTRACE_TYPE_ARG3) 0, 0);
+  target_mourn_inferior ();
 }
 
-/* Stub function which causes the GDB that runs it, to start ptrace-ing
-   the child process.  */
+/* Stop the inferior.  */
 
 static void
-inf_ptrace_him (int pid)
+inf_ptrace_stop (void)
 {
-  push_target (ptrace_ops_hack);
-
-  /* On some targets, there must be some explicit synchronization
-     between the parent and child processes after the debugger
-     forks, and before the child execs the debuggee program.  This
-     call basically gives permission for the child to exec.
-   */
-
-  target_acknowledge_created_inferior (pid);
-
-  /* START_INFERIOR_TRAPS_EXPECTED is defined in inferior.h,
-   * and will be 1 or 2 depending on whether we're starting
-   * without or with a shell.
-   */
-  startup_inferior (START_INFERIOR_TRAPS_EXPECTED);
-
-  /* On some targets, there must be some explicit actions taken after
-     the inferior has been started up.
-   */
-  target_post_startup_inferior (pid_to_ptid (pid));
+  /* Send a SIGINT to the process group.  This acts just like the user
+     typed a ^C on the controlling terminal.  Note that using a
+     negative process number in kill() is a System V-ism.  The proper
+     BSD interface is killpg().  However, all modern BSDs support the
+     System V interface too.  */
+  kill (-inferior_process_group, SIGINT);
 }
 
-/* Start an inferior Unix child process and sets inferior_ptid to its
-   pid.  EXEC_FILE is the file to run.  ALLARGS is a string containing
-   the arguments to the program.  ENV is the environment vector to
-   pass.  Errors reported with error().  */
+/* Resume execution of thread PTID, or all threads if PTID is -1.  If
+   STEP is nonzero, single-step it.  If SIGNAL is nonzero, give it
+   that signal.  */
 
 static void
-inf_ptrace_create_inferior (char *exec_file, char *allargs, char **env,
-			    int from_tty)
+inf_ptrace_resume (ptid_t ptid, int step, enum target_signal signal)
 {
-  fork_inferior (exec_file, allargs, env, inf_ptrace_me, inf_ptrace_him,
-		 NULL, NULL);
-  /* We are at the first instruction we care about.  */
-  observer_notify_inferior_created (&current_target, from_tty);
-  /* Pedal to the metal... */
-  proceed ((CORE_ADDR) -1, TARGET_SIGNAL_0, 0);
-}
+  pid_t pid = ptid_get_pid (ptid);
+  int request = PT_CONTINUE;
 
-static void
-inf_ptrace_post_startup_inferior (ptid_t ptid)
-{
-  /* This version of Unix doesn't require a meaningful "post startup inferior"
-     operation by a debugger.
-   */
-}
+  if (pid == -1)
+    /* Resume all threads.  Traditionally ptrace() only supports
+       single-threaded processes, so simply resume the inferior.  */
+    pid = ptid_get_pid (inferior_ptid);
 
-static void
-inf_ptrace_acknowledge_created_inferior (int pid)
-{
-  /* This version of Unix doesn't require a meaningful "acknowledge created inferior"
-     operation by a debugger.
-   */
-}
+  if (step)
+    {
+      /* If this system does not support PT_STEP, a higher level
+         function will have called single_step() to transmute the step
+         request into a continue request (by setting breakpoints on
+         all possible successor instructions), so we don't have to
+         worry about that here.  */
+      request = PT_STEP;
+    }
 
-static int
-inf_ptrace_insert_fork_catchpoint (int pid)
-{
-  /* This version of Unix doesn't support notification of fork events.  */
-  return 0;
+  /* An address of (PTRACE_TYPE_ARG3)1 tells ptrace to continue from
+     where it was.  If GDB wanted it to start some other way, we have
+     already written a new program counter value to the child.  */
+  errno = 0;
+  ptrace (request, pid, (PTRACE_TYPE_ARG3)1, target_signal_to_host (signal));
+  if (errno != 0)
+    perror_with_name (("ptrace"));
 }
 
-static int
-inf_ptrace_remove_fork_catchpoint (int pid)
-{
-  /* This version of Unix doesn't support notification of fork events.  */
-  return 0;
-}
+/* Wait for the child specified by PTID to do something.  Return the
+   process ID of the child, or MINUS_ONE_PTID in case of error; store
+   the status in *OURSTATUS.  */
 
-static int
-inf_ptrace_insert_vfork_catchpoint (int pid)
+static ptid_t
+inf_ptrace_wait (ptid_t ptid, struct target_waitstatus *ourstatus)
 {
-  /* This version of Unix doesn't support notification of vfork events.  */
-  return 0;
-}
+  pid_t pid;
+  int status, save_errno;
 
-static int
-inf_ptrace_remove_vfork_catchpoint (int pid)
-{
-  /* This version of Unix doesn't support notification of vfork events.  */
-  return 0;
-}
+  do
+    {
+      set_sigint_trap ();
+      set_sigio_trap ();
 
-static int
-inf_ptrace_follow_fork (int follow_child)
-{
-  /* This version of Unix doesn't support following fork or vfork events.  */
-  return 0;
-}
+      do
+	{
+	  pid = waitpid (ptid_get_pid (ptid), &status, 0);
+	  save_errno = errno;
+	}
+      while (pid == -1 && errno == EINTR);
 
-static int
-inf_ptrace_insert_exec_catchpoint (int pid)
-{
-  /* This version of Unix doesn't support notification of exec events.  */
-  return 0;
-}
+      clear_sigio_trap ();
+      clear_sigint_trap ();
 
-static int
-inf_ptrace_remove_exec_catchpoint (int pid)
-{
-  /* This version of Unix doesn't support notification of exec events.  */
-  return 0;
-}
+      if (pid == -1)
+	{
+	  fprintf_unfiltered (gdb_stderr,
+			      _("Child process unexpectedly missing: %s.\n"),
+			      safe_strerror (save_errno));
 
-static int
-inf_ptrace_reported_exec_events_per_exec_call (void)
-{
-  /* This version of Unix doesn't support notification of exec events.
-   */
-  return 1;
-}
+	  /* Claim it exited with unknown signal.  */
+	  ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
+	  ourstatus->value.sig = TARGET_SIGNAL_UNKNOWN;
+	  return minus_one_ptid;
+	}
 
-static int
-inf_ptrace_has_exited (int pid, int wait_status, int *exit_status)
-{
-  if (WIFEXITED (wait_status))
-    {
-      *exit_status = WEXITSTATUS (wait_status);
-      return 1;
+      /* Ignore terminated detached child processes.  */
+      if (!WIFSTOPPED (status) && pid != ptid_get_pid (inferior_ptid))
+	pid = -1;
     }
+  while (pid == -1);
 
-  if (WIFSIGNALED (wait_status))
+#ifdef PT_GET_PROCESS_STATE
+  if (WIFSTOPPED (status))
     {
-      *exit_status = 0;		/* ?? Don't know what else to say here. */
-      return 1;
-    }
-
-  /* ?? Do we really need to consult the event state, too?  Assume the
-     wait_state alone suffices.
-   */
-  return 0;
-}
-
-static void
-inf_ptrace_mourn_inferior (void)
-{
-  unpush_target (ptrace_ops_hack);
-  generic_mourn_inferior ();
-}
+      ptrace_state_t pe;
+      pid_t fpid;
 
-static int
-inf_ptrace_can_run (void)
-{
-  return 1;
-}
+      if (ptrace (PT_GET_PROCESS_STATE, pid,
+		  (PTRACE_TYPE_ARG3)&pe, sizeof pe) == -1)
+	perror_with_name (("ptrace"));
 
-/* Send a SIGINT to the process group.  This acts just like the user
-   typed a ^C on the controlling terminal.
+      switch (pe.pe_report_event)
+	{
+	case PTRACE_FORK:
+	  ourstatus->kind = TARGET_WAITKIND_FORKED;
+	  ourstatus->value.related_pid = pe.pe_other_pid;
+
+	  /* Make sure the other end of the fork is stopped too.  */
+	  fpid = waitpid (pe.pe_other_pid, &status, 0);
+	  if (fpid == -1)
+	    perror_with_name (("waitpid"));
+
+	  if (ptrace (PT_GET_PROCESS_STATE, fpid,
+		      (PTRACE_TYPE_ARG3)&pe, sizeof pe) == -1)
+	    perror_with_name (("ptrace"));
+
+	  gdb_assert (pe.pe_report_event == PTRACE_FORK);
+	  gdb_assert (pe.pe_other_pid == pid);
+	  if (fpid == ptid_get_pid (inferior_ptid))
+	    {
+	      ourstatus->value.related_pid = pe.pe_other_pid;
+	      return pid_to_ptid (fpid);
+	    }
 
-   XXX - This may not be correct for all systems.  Some may want to
-   use killpg() instead of kill (-pgrp). */
+	  return pid_to_ptid (pid);
+	}
+    }
+#endif
 
-static void
-inf_ptrace_stop (void)
-{
-  kill (-inferior_process_group, SIGINT);
+  store_waitstatus (ourstatus, status);
+  return pid_to_ptid (pid);
 }
 
-/* Perform a partial transfer to/from the specified object.  For
-   memory transfers, fall back to the old memory xfer functions.  */
+/* Attempt a transfer all LEN bytes starting at OFFSET between the
+   inferior's OBJECT:ANNEX space and GDB's READBUF/WRITEBUF buffer.
+   Return the number of bytes actually transferred.  */
 
 static LONGEST
 inf_ptrace_xfer_partial (struct target_ops *ops, enum target_object object,
 			 const char *annex, void *readbuf,
-			 const void *writebuf, ULONGEST offset, LONGEST len)
+			 const void *writebuf,
+			 ULONGEST offset, LONGEST len)
 {
+  pid_t pid = ptid_get_pid (inferior_ptid);
+
   switch (object)
     {
     case TARGET_OBJECT_MEMORY:
@@ -486,16 +460,16 @@ inf_ptrace_xfer_partial (struct target_ops *ops, enum target_object object,
 	 and writing data in the traced process's address space.  */
       {
 	struct ptrace_io_desc piod;
-	
+
 	/* NOTE: We assume that there are no distinct address spaces
 	   for instruction and data.  */
-	piod.piod_op = writebuf ? PIOD_WRITE_I : PIOD_READ_I;
+	piod.piod_op = writebuf ? PIOD_WRITE_I : PIOD_READ_D;
 	piod.piod_addr = writebuf ? (void *) writebuf : readbuf;
 	piod.piod_offs = (void *) (long) offset;
 	piod.piod_len = len;
 
 	errno = 0;
-	if (ptrace (PT_IO, PIDGET (inferior_ptid), (caddr_t) &piod, 0) == 0)
+	if (ptrace (PT_IO, pid, (caddr_t)&piod, 0) == 0)
 	  /* Return the actual number of bytes read or written.  */
 	  return piod.piod_len;
 	/* If the PT_IO request is somehow not supported, fallback on
@@ -509,15 +483,15 @@ inf_ptrace_xfer_partial (struct target_ops *ops, enum target_object object,
 	union
 	{
 	  PTRACE_TYPE_RET word;
-	  unsigned char byte[sizeof (PTRACE_TYPE_RET)];
+	  char byte[sizeof (PTRACE_TYPE_RET)];
 	} buffer;
 	ULONGEST rounded_offset;
 	LONGEST partial_len;
-	
+
 	/* Round the start offset down to the next long word
 	   boundary.  */
 	rounded_offset = offset & -(ULONGEST) sizeof (PTRACE_TYPE_RET);
-	
+
 	/* Since ptrace will transfer a single word starting at that
 	   rounded_offset the partial_len needs to be adjusted down to
 	   that (remember this function only does a single transfer).
@@ -526,7 +500,7 @@ inf_ptrace_xfer_partial (struct target_ops *ops, enum target_object object,
 	partial_len = (rounded_offset + sizeof (PTRACE_TYPE_RET)) - offset;
 	if (partial_len > len)
 	  partial_len = len;
-	
+
 	if (writebuf)
 	  {
 	    /* If OFFSET:PARTIAL_LEN is smaller than
@@ -536,41 +510,41 @@ inf_ptrace_xfer_partial (struct target_ops *ops, enum target_object object,
 		|| (offset + partial_len
 		    < rounded_offset + sizeof (PTRACE_TYPE_RET)))
 	      /* Need part of initial word -- fetch it.  */
-	      buffer.word = ptrace (PT_READ_I, PIDGET (inferior_ptid),
-				    (PTRACE_TYPE_ARG3) (long) rounded_offset,
-				    0);
-	    
+	      buffer.word = ptrace (PT_READ_I, pid,
+				    (PTRACE_TYPE_ARG3)(long)rounded_offset, 0);
+
 	    /* Copy data to be written over corresponding part of
 	       buffer.  */
-	    memcpy (buffer.byte + (offset - rounded_offset), writebuf, partial_len);
-	    
+	    memcpy (buffer.byte + (offset - rounded_offset),
+		    writebuf, partial_len);
+
 	    errno = 0;
-	    ptrace (PT_WRITE_D, PIDGET (inferior_ptid),
-		    (PTRACE_TYPE_ARG3) (long) rounded_offset,
-		    buffer.word);
+	    ptrace (PT_WRITE_D, pid,
+		    (PTRACE_TYPE_ARG3)(long)rounded_offset, buffer.word);
 	    if (errno)
 	      {
 		/* Using the appropriate one (I or D) is necessary for
 		   Gould NP1, at least.  */
 		errno = 0;
-		ptrace (PT_WRITE_I, PIDGET (inferior_ptid),
-			(PTRACE_TYPE_ARG3) (long) rounded_offset,
-			buffer.word);
+		ptrace (PT_WRITE_I, pid,
+			(PTRACE_TYPE_ARG3)(long)rounded_offset, buffer.word);
 		if (errno)
 		  return 0;
 	      }
 	  }
+
 	if (readbuf)
 	  {
 	    errno = 0;
-	    buffer.word = ptrace (PT_READ_I, PIDGET (inferior_ptid),
-				  (PTRACE_TYPE_ARG3) (long) rounded_offset, 0);
+	    buffer.word = ptrace (PT_READ_I, pid,
+				  (PTRACE_TYPE_ARG3)(long)rounded_offset, 0);
 	    if (errno)
 	      return 0;
 	    /* Copy appropriate bytes out of the buffer.  */
 	    memcpy (readbuf, buffer.byte + (offset - rounded_offset),
 		    partial_len);
 	  }
+
 	return partial_len;
       }
 
@@ -588,52 +562,173 @@ inf_ptrace_xfer_partial (struct target_ops *ops, enum target_object object,
     }
 }
 
-static char *
-inf_ptrace_pid_to_str (ptid_t ptid)
+/* Return non-zero if the thread specified by PTID is alive.  */
+
+static int
+inf_ptrace_thread_alive (ptid_t ptid)
+{
+  /* ??? Is kill the right way to do this?  */
+  return (kill (ptid_get_pid (ptid), 0) != -1);
+}
+
+/* Print status information about what we're accessing.  */
+
+static void
+inf_ptrace_files_info (struct target_ops *ignore)
 {
-  return normal_pid_to_str (ptid);
+  printf_filtered (_("\tUsing the running image of %s %s.\n"),
+		   attach_flag ? "attached" : "child",
+		   target_pid_to_str (inferior_ptid));
 }
 
+/* Create a prototype ptrace target.  The client can override it with
+   local methods.  */
+
 struct target_ops *
 inf_ptrace_target (void)
 {
   struct target_ops *t = inf_child_target ();
-  t->to_open = inf_ptrace_open;
+
   t->to_attach = inf_ptrace_attach;
-  t->to_post_attach = inf_ptrace_post_attach;
   t->to_detach = inf_ptrace_detach;
   t->to_resume = inf_ptrace_resume;
   t->to_wait = inf_ptrace_wait;
-  t->to_prepare_to_store = inf_ptrace_prepare_to_store;
-  t->to_xfer_partial = inf_ptrace_xfer_partial;
   t->to_files_info = inf_ptrace_files_info;
-  t->to_kill = inf_ptrace_kill_inferior;
+  t->to_kill = inf_ptrace_kill;
   t->to_create_inferior = inf_ptrace_create_inferior;
-  t->to_post_startup_inferior = inf_ptrace_post_startup_inferior;
-  t->to_acknowledge_created_inferior =
-    inf_ptrace_acknowledge_created_inferior;
-  t->to_insert_fork_catchpoint = inf_ptrace_insert_fork_catchpoint;
-  t->to_remove_fork_catchpoint = inf_ptrace_remove_fork_catchpoint;
-  t->to_insert_vfork_catchpoint = inf_ptrace_insert_vfork_catchpoint;
-  t->to_remove_vfork_catchpoint = inf_ptrace_remove_vfork_catchpoint;
+#ifdef PT_GET_PROCESS_STATE
   t->to_follow_fork = inf_ptrace_follow_fork;
-  t->to_insert_exec_catchpoint = inf_ptrace_insert_exec_catchpoint;
-  t->to_remove_exec_catchpoint = inf_ptrace_remove_exec_catchpoint;
-  t->to_reported_exec_events_per_exec_call =
-    inf_ptrace_reported_exec_events_per_exec_call;
-  t->to_has_exited = inf_ptrace_has_exited;
+  t->to_post_startup_inferior = inf_ptrace_post_startup_inferior;
+  t->to_post_attach = inf_ptrace_post_attach;
+#endif
   t->to_mourn_inferior = inf_ptrace_mourn_inferior;
-  t->to_can_run = inf_ptrace_can_run;
   t->to_thread_alive = inf_ptrace_thread_alive;
-  t->to_pid_to_str = inf_ptrace_pid_to_str;
+  t->to_pid_to_str = normal_pid_to_str;
   t->to_stop = inf_ptrace_stop;
-  t->to_stratum = process_stratum;
-  t->to_has_all_memory = 1;
-  t->to_has_memory = 1;
-  t->to_has_stack = 1;
-  t->to_has_registers = 1;
-  t->to_has_execution = 1;
-  t->to_magic = OPS_MAGIC;
+  t->to_xfer_partial = inf_ptrace_xfer_partial;
+
   ptrace_ops_hack = t;
   return t;
 }
+
+
+/* Pointer to a function that returns the offset within the user area
+   where a particular register is stored.  */
+static CORE_ADDR (*inf_ptrace_register_u_offset)(int);
+
+/* Fetch register REGNUM from the inferior.  */
+
+static void
+inf_ptrace_fetch_register (int regnum)
+{
+  CORE_ADDR addr;
+  size_t size;
+  PTRACE_TYPE_RET *buf;
+  int pid, i;
+
+  /* Cater for systems like GNU/Linux, that implement threads as
+     seperate processes.  */
+  pid = ptid_get_lwp (inferior_ptid);
+  if (pid == 0)
+    pid = ptid_get_pid (inferior_ptid);
+
+  /* This isn't really an address, but ptrace thinks of it as one.  */
+  addr = inf_ptrace_register_u_offset (regnum);
+  size = register_size (current_gdbarch, regnum);
+
+  gdb_assert ((size % sizeof (PTRACE_TYPE_RET)) == 0);
+  buf = alloca (size);
+
+  /* Read the register contents from the inferior a chuck at the time.  */
+  for (i = 0; i < size / sizeof (PTRACE_TYPE_RET); i++)
+    {
+      errno = 0;
+      buf[i] = ptrace (PT_READ_U, pid, (PTRACE_TYPE_ARG3)addr, 0);
+      if (errno != 0)
+	error (_("Couldn't read register %s (#%d): %s."),
+	       REGISTER_NAME (regnum), regnum, safe_strerror (errno));
+
+      addr += sizeof (PTRACE_TYPE_RET);
+    }
+  regcache_raw_supply (current_regcache, regnum, buf);
+}
+
+/* Fetch register REGNUM from the inferior.  If REGNUM is -1, do this
+   for all registers.  */
+
+static void
+inf_ptrace_fetch_registers (int regnum)
+{
+  if (regnum == -1)
+    for (regnum = 0; regnum < NUM_REGS; regnum++)
+      inf_ptrace_fetch_register (regnum);
+  else
+    inf_ptrace_fetch_register (regnum);
+}
+
+/* Store register REGNUM into the inferior.  */
+
+static void
+inf_ptrace_store_register (int regnum)
+{
+  CORE_ADDR addr;
+  size_t size;
+  PTRACE_TYPE_RET *buf;
+  int pid, i;
+
+  /* Cater for systems like GNU/Linux, that implement threads as
+     seperate processes.  */
+  pid = ptid_get_lwp (inferior_ptid);
+  if (pid == 0)
+    pid = ptid_get_pid (inferior_ptid);
+
+  /* This isn't really an address, but ptrace thinks of it as one.  */
+  addr = inf_ptrace_register_u_offset (regnum);
+  size = register_size (current_gdbarch, regnum);
+
+  gdb_assert ((size % sizeof (PTRACE_TYPE_RET)) == 0);
+  buf = alloca (size);
+
+  /* Write the register contents into the inferior a chunk at the time.  */
+  regcache_raw_collect (current_regcache, regnum, buf);
+  for (i = 0; i < size / sizeof (PTRACE_TYPE_RET); i++)
+    {
+      errno = 0;
+      ptrace (PT_WRITE_U, pid, (PTRACE_TYPE_ARG3)addr, buf[i]);
+      if (errno != 0)
+	error (_("Couldn't write register %s (#%d): %s."),
+	       REGISTER_NAME (regnum), regnum, safe_strerror (errno));
+
+      addr += sizeof (PTRACE_TYPE_RET);
+    }
+}
+
+/* Store register REGNUM back into the inferior.  If REGNUM is -1, do
+   this for all registers.  */
+
+void
+inf_ptrace_store_registers (int regnum)
+{
+  if (regnum == -1)
+    for (regnum = 0; regnum < NUM_REGS; regnum++)
+      inf_ptrace_store_register (regnum);
+  else
+    inf_ptrace_store_register (regnum);
+}
+
+/* Create a "traditional" ptrace target.  REGISTER_U_OFFSET should be
+   a function returning the offset within the user area where a
+   particular register is stored.  */
+
+struct target_ops *
+inf_ptrace_trad_target (CORE_ADDR (*register_u_offset)(int))
+{
+  struct target_ops *t = inf_ptrace_target();
+
+  gdb_assert (register_u_offset);
+  inf_ptrace_register_u_offset = register_u_offset;
+  t->to_fetch_registers = inf_ptrace_fetch_registers;
+  t->to_store_registers = inf_ptrace_store_registers;
+
+  return t;
+}