import gdb-2000-01-17 snapshot

1 files changed, 1095 insertions, 0 deletions

diff --git a/gdb/uw-thread.c b/gdb/uw-thread.c
new file mode 100644
index 0000000..91d6638
--- /dev/null
+++ b/gdb/uw-thread.c
@@ -0,0 +1,1095 @@
+/* Low level interface for debugging UnixWare user-mode threads for
+   GDB, the GNU debugger.
+
+   Copyright 1999, 2000 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 2 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, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+
+/* Like many systems, UnixWare implements two classes of threads:
+   kernel-mode threads, which are scheduled by the kernel; and
+   user-mode threads, which are scheduled by a library.  UnixWare
+   calls these two classes lightweight processes (LWPs) and threads,
+   respectively.
+
+   This module deals with user-mode threads.  It calls procfs_ops
+   functions to deal with LWPs and processes and core_ops functions to
+   deal with core files.
+
+   As of this writing, the user-mode thread debugging interface is not
+   documented beyond the comments in <thread.h>.  The following
+   description has been gleaned from experience and from information
+   provided by SCO.
+
+   libthread.so, against which all UnixWare user-mode thread programs
+   link, provides a global thread_debug structure named _thr_debug.
+   It has three fields:
+
+     (1) thr_map is a pointer to a pointer to an element of a
+	 thread_map ring.  A thread_map contains a single thread's id
+	 number, state, LWP pointer, recent register state, and other
+	 useful information.
+
+     (2) thr_brk is a pointer to a stub function that libthread.so
+	 calls when it changes a thread's state, e.g. by creating it,
+	 switching it to an LWP, or causing it to exit.
+
+     (3) thr_debug_on controls whether libthread.so calls thr_brk().
+
+   Debuggers are able to track thread activity by setting a private
+   breakpoint on thr_brk() and setting thr_debug_on to 1.
+
+   thr_brk() receives two arguments:
+
+     (1) a pointer to a thread_map describing the thread being
+	 changed; and
+
+     (2) an enum thread_change specifying one of the following
+	 changes:
+
+	 invalid		 unknown
+	 thread_create		 thread has just been created
+	 thread_exit		 thread has just exited
+	 switch_begin		 thread will be switched to an LWP
+	 switch_complete	 thread has been switched to an LWP
+	 cancel_complete	 thread wasn't switched to an LWP
+	 thread_suspend		 thread has been thr_suspend()ed
+	 thread_suspend_pending	 thread will be thr_suspend()ed
+	 thread_continue	 thread has been thr_continue()d
+
+   The thread_map argument to thr_brk() is NULL under the following
+   circumstances:
+
+     - The main thread is being acted upon.  The main thread always
+       has id 1, so its thread_map is easy to find by scanning through
+       _thr_debug.thr_map.
+
+     - A "switch_complete" change is occurring, which means that the
+       thread specified in the most recent "switch_begin" change has
+       moved to an LWP.
+
+     - A "cancel_complete" change is occurring, which means that the
+       thread specified in the most recent "switch_begin" change has
+       not moved to an LWP after all.
+
+     - A spurious "switch_begin" change is occurring after a
+       "thread_exit" change.
+
+   Between switch_begin and switch_complete or cancel_complete, the
+   affected thread's LWP pointer is not reliable.  It is possible that
+   other parts of the thread's thread_map are also unreliable during
+   that time. */
+
+
+#include "defs.h"
+#include "gdbthread.h"
+#include "target.h"
+#include "inferior.h"
+#include <fcntl.h>
+
+/*
+ * <thread.h> includes <sys/priocntl.h>, which requires boolean_t from
+ * <sys/types.h>, which doesn't typedef boolean_t with gcc.
+ */
+#define boolean_t int
+#include <thread.h>
+#undef boolean_t
+
+#include <synch.h>		/* for UnixWare 2.x */
+
+
+/*
+ * Whether to emit debugging output.
+ */
+#define DEBUG 0
+
+/*
+ * Default debugging output file, overridden by envvar UWTHR_DEBUG.
+ */
+#define DEBUG_FILE "/dev/tty"
+
+/*
+ * #if DEBUG, write string S to the debugging output channel.
+ */
+#if !DEBUG
+# define DBG(fmt_and_args)
+# define DBG2(fmt_and_args)
+#else
+# define DBG(fmt_and_args) dbg fmt_and_args
+# define DBG2(fmt_and_args)
+#endif
+
+/*
+ * Back end to CALL_BASE() and TRY_BASE(): evaluate CALL, then convert
+ * inferior_pid to a composite thread/process id.
+ */
+#define CALL_BASE_1(call)		\
+do {					\
+  DBG2(("CALL_BASE(" #call ")"));	\
+  call;					\
+  do_cleanups (infpid_cleanup);		\
+} while (0)
+
+/*
+ * If inferior_pid can be converted to a composite lwp/process id, do so,
+ * evaluate base_ops function CALL, and then convert inferior_pid back to a
+ * composite thread/process id.
+ *
+ * Otherwise, issue an error message and return nonlocally.
+ */
+#define CALL_BASE(call)					\
+do {							\
+  if (!lwp_infpid ())					\
+    error ("uw-thread: "__FUNCTION__": no lwp");	\
+  CALL_BASE_1 (call);					\
+} while (0)
+
+/*
+ * Like CALL_BASE(), but instead of returning nonlocally on error, set
+ * *CALLED to whether the inferior_pid conversion was successful.
+ */
+#define TRY_BASE(call, called)		\
+do {					\
+  if ((*(called) = lwp_infpid ()))	\
+    CALL_BASE_1 (call);			\
+} while (0)
+
+/*
+ * Information passed by thread_iter() to its callback parameter.
+ */
+typedef struct {
+  struct thread_map map;
+  __lwp_desc_t lwp;
+  CORE_ADDR mapp;
+} iter_t;
+
+/*
+ * Private thread data for the thread_info struct.
+ */
+struct private_thread_info {
+  int stable;		/* 0 if libthread.so is modifying thread map */
+  int thrid;		/* thread id assigned by libthread.so */
+  int lwpid;		/* thread's lwp if .stable, 0 means no lwp */
+  CORE_ADDR mapp;	/* address of thread's map structure */
+};
+
+
+/* procfs.c's target-specific operations. */
+extern struct target_ops procfs_ops;
+
+/* Flag to prevent procfs.c from starting inferior processes. */
+extern int procfs_suppress_run;
+
+/* This module's target-specific operations. */
+static struct target_ops uw_thread_ops;
+
+/* Copy of the target over which uw_thread_ops is pushed.  This is
+   more convenient than a pointer to procfs_ops or core_ops, because
+   they lack current_target's default callbacks. */
+static struct target_ops base_ops;
+
+/* Saved pointer to previous owner of target_new_objfile_hook. */
+static void (*target_new_objfile_chain)(struct objfile *);
+
+/* Whether we are debugging a user-space thread program.  This isn't
+   set until after libthread.so is loaded by the program being
+   debugged.
+
+   Except for module one-time intialization and where otherwise
+   documented, no functions in this module get called when
+   !uw_thread_active. */
+static int uw_thread_active;
+
+/* For efficiency, cache the addresses of libthread.so's _thr_debug
+   structure, its thr_brk stub function, and the main thread's map. */
+static CORE_ADDR thr_debug_addr;
+static CORE_ADDR thr_brk_addr;
+static CORE_ADDR thr_map_main;
+
+/* Remember the thread most recently marked as switching.  Necessary because
+   libthread.so passes null map when calling stub with tc_*_complete. */
+static struct thread_info *switchto_thread;
+
+/* Cleanup chain for safely restoring inferior_pid after CALL_BASE. */
+static struct cleanup *infpid_cleanup;
+
+
+#if DEBUG
+/*
+ * Helper function for DBG() macro: if printf-style FMT is non-null, format it
+ * with args and display the result on the debugging output channel.
+ */
+static void
+dbg (char *fmt, ...)
+{
+  static int fd = -1, len;
+  va_list args;
+  char buf[1024];
+  char *path;
+
+  if (!fmt)
+    return;
+
+  if (fd < 0)
+    {
+      path = getenv ("UWTHR_DEBUG");
+      if (!path)
+	path = DEBUG_FILE;
+      if ((fd = open (path, O_WRONLY | O_CREAT | O_TRUNC, 0664)) < 0)
+	error ("can't open %s\n", path);
+    }
+
+  va_start (args, fmt);
+  vsprintf (buf, fmt, args);
+  va_end (args);
+
+  len = strlen (buf);
+  buf[len] = '\n';
+  (void)write (fd, buf, len + 1);
+}
+
+#if 0
+/*
+ * Return a string representing composite PID's components.
+ */
+static char *
+dbgpid (int pid)
+{
+  static char *buf, buf1[80], buf2[80];
+  if (!buf || buf == buf2)
+    buf = buf1;
+  else
+    buf = buf2;
+
+  if (pid <= 0)
+    sprintf (buf, "%d", pid);
+  else
+    sprintf (buf, "%s %d/%d", ISTID (pid) ? "thr" : "lwp",
+	     TIDGET (pid), PIDGET (pid));
+
+  return buf;
+}
+
+/*
+ * Return a string representing thread state CHANGE.
+ */
+static char *
+dbgchange (enum thread_change change)
+{
+  switch (change) {
+  case tc_invalid:			return "invalid";
+  case tc_thread_create:		return "thread_create";
+  case tc_thread_exit:			return "thread_exit";
+  case tc_switch_begin:			return "switch_begin";
+  case tc_switch_complete:		return "switch_complete";
+  case tc_cancel_complete:		return "cancel_complete";
+  case tc_thread_suspend:		return "thread_suspend";
+  case tc_thread_suspend_pending:	return "thread_suspend_pending";
+  case tc_thread_continue:		return "thread_continue";
+  default:				return "unknown";
+  }
+}
+
+/*
+ * Return a string representing thread STATE.
+ */
+static char *
+dbgstate (int state)
+{
+  switch (state) {
+  case TS_ONPROC:	return "running";
+  case TS_SLEEP:	return "sleeping";
+  case TS_RUNNABLE:	return "runnable";
+  case TS_ZOMBIE:	return "zombie";
+  case TS_SUSPENDED:	return "suspended";
+#ifdef TS_FORK
+  case TS_FORK:		return "forking";
+#endif
+  default:		return "confused";
+  }
+}
+#endif  /* 0 */
+#endif  /* DEBUG */
+
+
+/*
+ * Read the contents of _thr_debug into *DEBUGP.  Return success.
+ */
+static int
+read_thr_debug (struct thread_debug *debugp)
+{
+  return base_ops.to_xfer_memory (thr_debug_addr, (char *)debugp,
+				  sizeof (*debugp), 0, &base_ops);
+}
+
+/*
+ * Read into MAP the contents of the thread map at inferior process address
+ * MAPP.  Return success.
+ */
+static int
+read_map (CORE_ADDR mapp, struct thread_map *map)
+{
+  return base_ops.to_xfer_memory ((CORE_ADDR)THR_MAP (mapp), (char *)map,
+				  sizeof (*map), 0, &base_ops);
+}
+
+/*
+ * Read into LWP the contents of the lwp decriptor at inferior process address
+ * LWPP.  Return success.
+ */
+static int
+read_lwp (CORE_ADDR lwpp, __lwp_desc_t *lwp)
+{
+  return base_ops.to_xfer_memory (lwpp, (char *)lwp,
+				  sizeof (*lwp), 0, &base_ops);
+}
+
+/*
+ * Iterate through all user threads, applying FUNC(<map>, <lwp>, DATA) until
+ *   (a) FUNC returns nonzero,
+ *   (b) FUNC has been applied to all threads, or
+ *   (c) an error occurs,
+ * where <map> is the thread's struct thread_map and <lwp> if non-null is the
+ * thread's current __lwp_desc_t.
+ *
+ * If a call to FUNC returns nonzero, return that value; otherwise, return 0.
+ */
+static int
+thread_iter (int (*func)(iter_t *, void *), void *data)
+{
+  struct thread_debug debug;
+  CORE_ADDR first, mapp;
+  iter_t iter;
+  int ret;
+
+  if (!read_thr_debug (&debug))
+    return 0;
+  if (!base_ops.to_xfer_memory ((CORE_ADDR)debug.thr_map, (char *)&mapp,
+				sizeof (mapp), 0, &base_ops))
+    return 0;
+  if (!mapp)
+    return 0;
+
+  for (first = mapp;;)
+    {
+      if (!read_map (mapp, &iter.map))
+	return 0;
+
+      if (iter.map.thr_lwpp)
+	if (!read_lwp ((CORE_ADDR)iter.map.thr_lwpp, &iter.lwp))
+	  return 0;
+
+      iter.mapp = mapp;
+      if ((ret = func (&iter, data)))
+	return ret;
+
+      mapp = (CORE_ADDR)iter.map.thr_next;
+      if (mapp == first)
+	return 0;
+    }
+}
+
+/*
+ * Deactivate user-mode thread support.
+ */
+static void
+deactivate_uw_thread (void)
+{
+  uw_thread_active = 0;
+  unpush_target (&uw_thread_ops);
+}
+
+/*
+ * Return the composite lwp/process id corresponding to composite
+ * id PID.  If PID is a thread with no lwp, return 0.
+ */
+static int
+thr_to_lwp (int pid)
+{
+  struct thread_info *info;
+  int lid;
+
+  if (!ISTID (pid))
+    lid = pid;
+  else if (!(info = find_thread_pid (pid)))
+    lid = 0;
+  else if (!info->private->lwpid)
+    lid = 0;
+  else
+    lid = MKLID (pid, info->private->lwpid);
+
+  DBG2(("  thr_to_lwp(%s) = %s", dbgpid (pid), dbgpid (lid)));
+  return lid;
+}
+
+/*
+ * find_thread_lwp() callback: return whether TP describes a thread
+ * associated with lwp id DATA.
+ */
+static int
+find_thread_lwp_callback (struct thread_info *tp, void *data)
+{
+  int lwpid = (int)data;
+
+  if (!ISTID (tp->pid))
+    return 0;
+  if (!tp->private->stable)
+    return 0;
+  if (lwpid != tp->private->lwpid)
+    return 0;
+
+  /* match */
+  return 1;
+}
+
+/*
+ * If a thread is associated with lwp id LWPID, return the corresponding
+ * member of the global thread list; otherwise, return null.
+ */
+static struct thread_info *
+find_thread_lwp (int lwpid)
+{
+  return iterate_over_threads (find_thread_lwp_callback, (void *)lwpid);
+}
+
+/*
+ * Return the composite thread/process id corresponding to composite
+ * id PID.  If PID is an lwp with no thread, return PID.
+ */
+static int
+lwp_to_thr (int pid)
+{
+  struct thread_info *info;
+  int tid = pid, lwpid;
+
+  if (ISTID (pid))
+    goto done;
+  if (!(lwpid = LIDGET (pid)))
+    goto done;
+  if (!(info = find_thread_lwp (lwpid)))
+    goto done;
+  tid = MKTID (pid, info->private->thrid);
+
+ done:
+  DBG2((ISTID (tid) ? NULL : "lwp_to_thr: no thr for %s", dbgpid (pid)));
+  return tid;
+}
+
+/*
+ * do_cleanups() callback: convert inferior_pid to a composite
+ * thread/process id after having made a procfs call.
+ */
+static void
+thr_infpid (void *unused)
+{
+  int pid = lwp_to_thr (inferior_pid);
+  DBG2((" inferior_pid from procfs: %s => %s",
+	dbgpid (inferior_pid), dbgpid (pid)));
+  inferior_pid = pid;
+}
+
+/*
+ * If possible, convert inferior_pid to a composite lwp/process id in
+ * preparation for making a procfs call.  Return success.
+ */
+static int
+lwp_infpid (void)
+{
+  int pid = thr_to_lwp (inferior_pid);
+  DBG2((" inferior_pid to procfs: %s => %s",
+	dbgpid (inferior_pid), dbgpid (pid)));
+
+  if (!pid)
+    return 0;
+
+  inferior_pid = pid;
+  infpid_cleanup = make_cleanup (thr_infpid, NULL);
+  return 1;
+}
+
+/*
+ * Add to the global thread list a new user-mode thread with system id THRID,
+ * lwp id LWPID, map address MAPP, and composite thread/process PID.
+ */
+static void
+add_thread_uw (int thrid, int lwpid, CORE_ADDR mapp, int pid)
+{
+  struct thread_info *newthread;
+
+  if ((newthread = add_thread (pid)) == NULL)
+    error ("failed to create new thread structure");
+
+  newthread->private = xmalloc (sizeof (struct private_thread_info));
+  newthread->private->stable = 1;
+  newthread->private->thrid = thrid;
+  newthread->private->lwpid = lwpid;
+  newthread->private->mapp = mapp;
+
+  if (target_has_execution)
+    printf_unfiltered ("[New %s]\n", target_pid_to_str (pid));
+}
+
+/*
+ * notice_threads() and find_main() callback: if the thread list doesn't
+ * already contain the thread described by ITER, add it if it's the main
+ * thread or if !DATA.
+ */
+static int
+notice_thread (iter_t *iter, void *data)
+{
+  int thrid = iter->map.thr_tid;
+  int lwpid = !iter->map.thr_lwpp ? 0 : iter->lwp.lwp_id;
+  int pid = MKTID (inferior_pid, thrid);
+
+  if (!find_thread_pid (pid) && (!data || thrid == 1))
+    add_thread_uw (thrid, lwpid, iter->mapp, pid);
+
+  return 0;
+}
+
+/*
+ * Add to the thread list any threads it doesn't already contain.
+ */
+static void
+notice_threads (void)
+{
+  thread_iter (notice_thread, NULL);
+}
+
+/*
+ * Return the address of the main thread's map.  On error, return 0.
+ */
+static CORE_ADDR
+find_main (void)
+{
+  if (!thr_map_main)
+    {
+      struct thread_info *info;
+      thread_iter (notice_thread, (void *)1);
+      if ((info = find_thread_pid (MKTID (inferior_pid, 1))))
+	thr_map_main = info->private->mapp;
+    }
+  return thr_map_main;
+}
+
+/*
+ * Attach to process specified by ARGS, then initialize for debugging it
+ * and wait for the trace-trap that results from attaching.
+ *
+ * This function only gets called with uw_thread_active == 0.
+ */
+static void
+uw_thread_attach (char *args, int from_tty)
+{
+  procfs_ops.to_attach (args, from_tty);
+  if (uw_thread_active)
+    thr_infpid (NULL);
+}
+
+/*
+ * Detach from the process attached to by uw_thread_attach().
+ */
+static void
+uw_thread_detach (char *args, int from_tty)
+{
+  deactivate_uw_thread ();
+  base_ops.to_detach (args, from_tty);
+}
+
+/*
+ * Tell the inferior process to continue running thread PID if >= 0
+ * and all threads otherwise.
+ */
+static void
+uw_thread_resume (int pid, int step, enum target_signal signo)
+{
+  if (pid > 0 && !(pid = thr_to_lwp (pid)))
+    pid = -1;
+
+  CALL_BASE (base_ops.to_resume (pid, step, signo));
+}
+
+/*
+ * If the trap we just received from lwp PID was due to a breakpoint
+ * on the libthread.so debugging stub, update this module's state
+ * accordingly.
+ */
+static void
+libthread_stub (int pid)
+{
+  CORE_ADDR sp, mapp, mapp_main;
+  enum thread_change change;
+  struct thread_map map;
+  __lwp_desc_t lwp;
+  int tid = 0, lwpid;
+  struct thread_info *info;
+
+  /* Check for stub breakpoint. */
+  if (read_pc_pid (pid) - DECR_PC_AFTER_BREAK != thr_brk_addr)
+    return;
+
+  /* Retrieve stub args. */
+  sp = read_register_pid (SP_REGNUM, pid);
+  if (!base_ops.to_xfer_memory (sp + SP_ARG0, (char *)&mapp,
+				sizeof (mapp), 0, &base_ops))
+    goto err;
+  if (!base_ops.to_xfer_memory (sp + SP_ARG0 + sizeof (mapp), (char *)&change,
+				sizeof (change), 0, &base_ops))
+    goto err;
+
+  /* create_inferior() may not have finished yet, so notice the main
+     thread to ensure that it's displayed first by add_thread(). */
+  mapp_main = find_main ();
+
+  /* Notice thread creation, deletion, or stability change. */
+  switch (change) {
+  case tc_switch_begin:
+    if (!mapp)				/* usually means main thread */
+      mapp = mapp_main;
+    /* fall through */
+
+  case tc_thread_create:
+  case tc_thread_exit:
+    if (!mapp)
+      break;
+    if (!read_map (mapp, &map))
+      goto err;
+    tid = MKTID (pid, map.thr_tid);
+
+    switch (change) {
+    case tc_thread_create:		/* new thread */
+      if (!map.thr_lwpp)
+	lwpid = 0;
+      else if (!read_lwp ((CORE_ADDR)map.thr_lwpp, &lwp))
+	goto err;
+      else
+	lwpid = lwp.lwp_id;
+      add_thread_uw (map.thr_tid, lwpid, mapp, tid);
+      break;
+
+    case tc_thread_exit:		/* thread has exited */
+      printf_unfiltered ("[Exited %s]\n", target_pid_to_str (tid));
+      delete_thread (tid);
+      if (tid == inferior_pid)
+	inferior_pid = pid;
+      break;
+
+    case tc_switch_begin:		/* lwp is switching threads */
+      if (switchto_thread)
+	goto err;
+      if (!(switchto_thread = find_thread_pid (tid)))
+	goto err;
+      switchto_thread->private->stable = 0;
+      break;
+
+    default:
+      break;
+    }
+    break;
+
+  case tc_switch_complete:		/* lwp has switched threads */
+  case tc_cancel_complete:		/* lwp didn't switch threads */
+    if (!switchto_thread)
+      goto err;
+
+    if (change == tc_switch_complete)
+      {
+	/*
+	 * If switchto_thread is the main thread, then (a) the corresponding
+	 * tc_switch_begin probably received a null map argument and therefore
+	 * (b) it may have been a spurious switch following a tc_thread_exit.
+	 *
+	 * Therefore, explicitly query the thread's lwp before caching it in
+	 * its thread list entry.
+	 */
+	if (!read_map (switchto_thread->private->mapp, &map))
+	  goto err;
+	if (map.thr_lwpp)
+	  {
+	    if (!read_lwp ((CORE_ADDR)map.thr_lwpp, &lwp))
+	      goto err;
+	    if ((info = find_thread_lwp (lwp.lwp_id)))
+	      info->private->lwpid = 0;
+	    switchto_thread->private->lwpid = lwp.lwp_id;
+	  }
+      }
+
+    switchto_thread->private->stable = 1;
+    switchto_thread = NULL;
+    break;
+
+  case tc_invalid:
+  case tc_thread_suspend:
+  case tc_thread_suspend_pending:
+  case tc_thread_continue:
+  err:
+    DBG(("unexpected condition in libthread_stub()"));
+    break;
+  }
+
+  DBG2(("libthread_stub(%s): %s %s %s", dbgpid (pid), dbgpid (tid),
+	dbgchange (change), tid ? dbgstate (map.thr_state) : ""));
+}
+
+/*
+ * Wait for thread/lwp/process ID if >= 0 or for any thread otherwise.
+ */
+static int
+uw_thread_wait (int pid, struct target_waitstatus *status)
+{
+  if (pid > 0)
+    pid = thr_to_lwp (pid);
+  CALL_BASE (pid = base_ops.to_wait (pid > 0 ? pid : -1, status));
+
+  if (status->kind == TARGET_WAITKIND_STOPPED &&
+      status->value.sig == TARGET_SIGNAL_TRAP)
+    libthread_stub (pid);
+
+  return lwp_to_thr (pid);
+}
+
+/*
+ * Tell gdb about the registers in the thread/lwp/process specified by
+ * inferior_pid.
+ */
+static void
+uw_thread_fetch_registers (int regno)
+{
+  int called;
+  struct thread_info *info;
+  struct thread_map map;
+
+  TRY_BASE (base_ops.to_fetch_registers (regno), &called);
+  if (called)
+    return;
+
+  if (!(info = find_thread_pid (inferior_pid)))
+    return;
+  if (!read_map (info->private->mapp, &map))
+    return;
+
+  supply_gregset (&map.thr_ucontext.uc_mcontext.gregs);
+  supply_fpregset (&map.thr_ucontext.uc_mcontext.fpregs);
+}
+
+/*
+ * Store gdb's current view of the register set into the thread/lwp/process
+ * specified by inferior_pid.
+ */
+static void
+uw_thread_store_registers (int regno)
+{
+  CALL_BASE (base_ops.to_store_registers (regno));
+}
+
+/*
+ * Prepare to modify the registers array.
+ */
+static void
+uw_thread_prepare_to_store (void)
+{
+  CALL_BASE (base_ops.to_prepare_to_store ());
+}
+
+/*
+ * Fork an inferior process and start debugging it.
+ *
+ * This function only gets called with uw_thread_active == 0.
+ */
+static void
+uw_thread_create_inferior (char *exec_file, char *allargs, char **env)
+{
+  if (uw_thread_active)
+    deactivate_uw_thread ();
+
+  procfs_ops.to_create_inferior (exec_file, allargs, env);
+  if (uw_thread_active)
+    {
+      find_main ();
+      thr_infpid (NULL);
+    }
+}
+
+/*
+ * Kill and forget about the inferior process.
+ */
+static void
+uw_thread_kill (void)
+{
+  base_ops.to_kill ();
+}
+
+/*
+ * Clean up after the inferior exits.
+ */
+static void
+uw_thread_mourn_inferior (void)
+{
+  remove_thread_event_breakpoints ();
+  deactivate_uw_thread ();
+  base_ops.to_mourn_inferior ();
+}
+
+/*
+ * Return whether this module can attach to and run processes.
+ *
+ * This function only gets called with uw_thread_active == 0.
+ */
+static int
+uw_thread_can_run (void)
+{
+  return procfs_suppress_run;
+}
+
+/*
+ * Return whether thread PID is still valid.
+ */
+static int
+uw_thread_alive (int pid)
+{
+  if (!ISTID (pid))
+    return base_ops.to_thread_alive (pid);
+
+  /* If it's in the thread list, it's valid, because otherwise
+     libthread_stub() would have deleted it. */
+  return in_thread_list (pid);
+}
+
+/*
+ * Add to the thread list any threads and lwps it doesn't already contain.
+ */
+static void
+uw_thread_find_new_threads (void)
+{
+  CALL_BASE (if (base_ops.to_find_new_threads)
+	       base_ops.to_find_new_threads ());
+  notice_threads ();
+}
+
+/*
+ * Return a string for pretty-printing PID in "info threads" output.
+ * This may be called by either procfs.c or by generic gdb.
+ */
+static char *
+uw_thread_pid_to_str (int pid)
+{
+#define FMT "Thread %d"
+  static char buf[sizeof (FMT) + 3 * sizeof (pid)];
+
+  if (!ISTID (pid))
+    /* core_ops says "process foo", so call procfs_ops explicitly. */
+    return procfs_ops.to_pid_to_str (pid);
+
+  sprintf (buf, FMT, TIDGET (pid));
+#undef FMT
+  return buf;
+}
+
+/*
+ * Return a string displaying INFO state information in "info threads"
+ * output.
+ */
+static char *
+uw_extra_thread_info (struct thread_info *info)
+{
+  static char buf[80];
+  struct thread_map map;
+  __lwp_desc_t lwp;
+  int lwpid;
+  char *name;
+
+  if (!ISTID (info->pid))
+    return NULL;
+
+  if (!info->private->stable)
+    return "switching";
+
+  if (!read_map (info->private->mapp, &map))
+    return NULL;
+
+  if (!map.thr_lwpp || !read_lwp ((CORE_ADDR)map.thr_lwpp, &lwp))
+    lwpid = 0;
+  else
+    lwpid = lwp.lwp_id;
+
+  switch (map.thr_state) {
+  case TS_ONPROC:	name = "running";	break;
+  case TS_SLEEP:	name = "sleeping";	break;
+  case TS_RUNNABLE:	name = "runnable";	break;
+  case TS_ZOMBIE:	name = "zombie";	break;
+  case TS_SUSPENDED:	name = "suspended";	break;
+#ifdef TS_FORK
+  case TS_FORK:		name = "forking";	break;
+#endif
+  default:		name = "confused";	break;
+  }
+
+  if (!lwpid)
+    return name;
+
+  sprintf (buf, "%s, LWP %d", name, lwpid);
+  return buf;
+}
+
+/*
+ * Check whether libthread.so has just been loaded, and if so, try to
+ * initialize user-space thread debugging support.
+ *
+ * libthread.so loading happens while (a) an inferior process is being
+ * started by procfs and (b) a core image is being loaded.
+ *
+ * This function often gets called with uw_thread_active == 0.
+ */
+static void
+libthread_init (void)
+{
+  struct minimal_symbol *ms;
+  struct thread_debug debug;
+  CORE_ADDR onp;
+  struct breakpoint *b;
+  int one = 1;
+
+  /* Don't initialize twice. */
+  if (uw_thread_active)
+    return;
+
+  /* Check whether libthread.so has been loaded. */
+  if (!(ms = lookup_minimal_symbol ("_thr_debug", NULL, NULL)))
+    return;
+
+  /* Cache _thr_debug's address. */
+  if (!(thr_debug_addr = SYMBOL_VALUE_ADDRESS (ms)))
+    return;
+
+  /* Initialize base_ops.to_xfer_memory(). */
+  base_ops = current_target;
+
+  /* Load _thr_debug's current contents. */
+  if (!read_thr_debug (&debug))
+    return;
+
+  /* User code (e.g. my test programs) may dereference _thr_debug,
+     making it availble to GDB before shared libs are loaded. */
+  if (!debug.thr_map)
+    return;
+
+  /* libthread.so has been loaded, and the current_target should now
+     reflect core_ops or procfs_ops. */
+  push_target (&uw_thread_ops);		/* must precede notice_threads() */
+  uw_thread_active = 1;
+
+  if (!target_has_execution)
+
+    /* Locate threads in core file. */
+    notice_threads ();
+
+  else
+    {
+      /* Set a breakpoint on the stub function provided by libthread.so. */
+      thr_brk_addr = (CORE_ADDR)debug.thr_brk;
+      if (!(b = create_thread_event_breakpoint (thr_brk_addr)))
+	goto err;
+
+      /* Activate the stub function. */
+      onp = (CORE_ADDR)&((struct thread_debug *)thr_debug_addr)->thr_debug_on;
+      if (!base_ops.to_xfer_memory ((CORE_ADDR)onp, (char *)&one,
+				    sizeof (one), 1, &base_ops))
+	{
+	  delete_breakpoint (b);
+	  goto err;
+	}
+
+      /* Prepare for finding the main thread, which doesn't yet exist. */
+      thr_map_main = 0;
+    }
+
+  return;
+
+ err:
+  warning ("uw-thread: unable to initialize user-mode thread debugging\n");
+  deactivate_uw_thread ();
+}
+
+/*
+ * target_new_objfile_hook callback.
+ *
+ * If OBJFILE is non-null, check whether libthread.so was just loaded,
+ * and if so, prepare for user-mode thread debugging.
+ *
+ * If OBJFILE is null, libthread.so has gone away, so stop debugging
+ * user-mode threads.
+ *
+ * This function often gets called with uw_thread_active == 0.
+ */
+static void
+uw_thread_new_objfile (struct objfile *objfile)
+{
+  if (objfile)
+    libthread_init ();
+
+  else if (uw_thread_active)
+    deactivate_uw_thread ();
+
+  if (target_new_objfile_chain)
+    target_new_objfile_chain (objfile);
+}
+
+/*
+ * Initialize uw_thread_ops.
+ */
+static void
+init_uw_thread_ops (void)
+{
+  uw_thread_ops.to_shortname          = "unixware-threads";
+  uw_thread_ops.to_longname           = "UnixWare threads and pthread.";
+  uw_thread_ops.to_doc        = "UnixWare threads and pthread support.";
+  uw_thread_ops.to_attach             = uw_thread_attach;
+  uw_thread_ops.to_detach             = uw_thread_detach;
+  uw_thread_ops.to_resume             = uw_thread_resume;
+  uw_thread_ops.to_wait               = uw_thread_wait;
+  uw_thread_ops.to_fetch_registers    = uw_thread_fetch_registers;
+  uw_thread_ops.to_store_registers    = uw_thread_store_registers;
+  uw_thread_ops.to_prepare_to_store   = uw_thread_prepare_to_store;
+  uw_thread_ops.to_create_inferior    = uw_thread_create_inferior;
+  uw_thread_ops.to_kill               = uw_thread_kill;
+  uw_thread_ops.to_mourn_inferior     = uw_thread_mourn_inferior;
+  uw_thread_ops.to_can_run            = uw_thread_can_run;
+  uw_thread_ops.to_thread_alive       = uw_thread_alive;
+  uw_thread_ops.to_find_new_threads   = uw_thread_find_new_threads;
+  uw_thread_ops.to_pid_to_str         = uw_thread_pid_to_str;
+  uw_thread_ops.to_extra_thread_info  = uw_extra_thread_info;
+  uw_thread_ops.to_stratum            = thread_stratum;
+  uw_thread_ops.to_magic              = OPS_MAGIC;
+}
+
+/*
+ * Module startup initialization function, automagically called by
+ * init.c.
+ */
+void
+_initialize_uw_thread (void)
+{
+  init_uw_thread_ops ();
+  add_target (&uw_thread_ops);
+
+  procfs_suppress_run = 1;
+
+  /* Notice when libthread.so gets loaded. */
+  target_new_objfile_chain = target_new_objfile_hook;
+  target_new_objfile_hook = uw_thread_new_objfile;
+}