gdb/libgdb/fbsd-threads.c

/* $FreeBSD: head/gnu/usr.bin/gdb/libgdb/fbsd-threads.c 134149 2004-08-22 08:48:56Z davidxu $ */
/* FreeBSD libthread_db assisted debugging support.
   Copyright 1999, 2000, 2001 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.  */

#include <dlfcn.h>
#include <sys/types.h>
#include <sys/ptrace.h>

#include "proc_service.h"
#include "thread_db.h"

#include "defs.h"
#include "bfd.h"
#include "elf-bfd.h"
#include "gdb_assert.h"
#include "gdbcore.h"
#include "gdbthread.h"
#include "inferior.h"
#include "objfiles.h"
#include "regcache.h"
#include "symfile.h"
#include "symtab.h"
#include "target.h"
#include "gdbcmd.h"
#include "solib-svr4.h"


#define LIBTHREAD_DB_SO "libthread_db.so"

struct ps_prochandle
{
  pid_t pid;
};

extern int child_suppress_run;

extern struct target_ops child_ops;

/* This module's target vector.  */
static struct target_ops fbsd_thread_ops;
static struct target_ops fbsd_core_ops;

/* Saved copy of orignal core_ops. */
static struct target_ops orig_core_ops;
extern struct target_ops core_ops;

/* Pointer to the next function on the objfile event chain.  */
static void (*target_new_objfile_chain) (struct objfile *objfile);

/* Non-zero if there is a thread module */
static int fbsd_thread_present;

/* Non-zero if we're using this module's target vector.  */
static int fbsd_thread_active;

/* Non-zero if core_open is called */
static int fbsd_thread_core = 0;

/* Non-zero if we have to keep this module's target vector active
   across re-runs.  */
static int keep_thread_db;

/* Structure that identifies the child process for the
   <proc_service.h> interface.  */
static struct ps_prochandle proc_handle;

/* Connection to the libthread_db library.  */
static td_thragent_t *thread_agent;

/* The last thread we are single stepping */
static ptid_t last_single_step_thread;

/* Pointers to the libthread_db functions.  */

static td_err_e (*td_init_p) (void);

static td_err_e (*td_ta_new_p) (struct ps_prochandle *ps, td_thragent_t **ta);
static td_err_e (*td_ta_delete_p) (td_thragent_t *);
static td_err_e (*td_ta_map_id2thr_p) (const td_thragent_t *ta, thread_t pt,
				       td_thrhandle_t *__th);
static td_err_e (*td_ta_map_lwp2thr_p) (const td_thragent_t *ta, lwpid_t lwpid,
					td_thrhandle_t *th);
static td_err_e (*td_ta_thr_iter_p) (const td_thragent_t *ta,
				     td_thr_iter_f *callback,
				     void *cbdata_p, td_thr_state_e state,
				     int ti_pri, sigset_t *ti_sigmask_p,
				     unsigned int ti_user_flags);
static td_err_e (*td_ta_event_addr_p) (const td_thragent_t *ta,
				       td_event_e event, td_notify_t *ptr);
static td_err_e (*td_ta_set_event_p) (const td_thragent_t *ta,
				      td_thr_events_t *event);
static td_err_e (*td_ta_event_getmsg_p) (const td_thragent_t *ta,
					 td_event_msg_t *msg);
static td_err_e (*td_thr_get_info_p) (const td_thrhandle_t *th,
				      td_thrinfo_t *infop);
static td_err_e (*td_thr_getfpregs_p) (const td_thrhandle_t *th,
				       prfpregset_t *regset);
static td_err_e (*td_thr_getgregs_p) (const td_thrhandle_t *th,
				      prgregset_t gregs);
static td_err_e (*td_thr_setfpregs_p) (const td_thrhandle_t *th,
				       const prfpregset_t *fpregs);
static td_err_e (*td_thr_setgregs_p) (const td_thrhandle_t *th,
				      prgregset_t gregs);
static td_err_e (*td_thr_event_enable_p) (const td_thrhandle_t *th, int event);

static td_err_e (*td_thr_sstep_p) (td_thrhandle_t *th, int step);

static td_err_e (*td_ta_tsd_iter_p) (const td_thragent_t *ta,
				 td_key_iter_f *func, void *data);
static td_err_e (*td_thr_tls_get_addr_p) (const td_thrhandle_t *th,
                                          void *map_address,
                                          size_t offset, void **address);
static td_err_e (*td_thr_dbsuspend_p) (const td_thrhandle_t *);
static td_err_e (*td_thr_dbresume_p) (const td_thrhandle_t *);

/* Prototypes for local functions.  */
static void fbsd_thread_find_new_threads (void);
static int fbsd_thread_alive (ptid_t ptid);

/* Building process ids.  */

#define GET_PID(ptid)		ptid_get_pid (ptid)
#define GET_LWP(ptid)		ptid_get_lwp (ptid)
#define GET_THREAD(ptid)	ptid_get_tid (ptid)

#define IS_LWP(ptid)		(GET_LWP (ptid) != 0)
#define IS_THREAD(ptid)		(GET_THREAD (ptid) != 0)

#define BUILD_LWP(lwp, pid)	ptid_build (pid, lwp, 0)
#define BUILD_THREAD(tid, pid)	ptid_build (pid, 0, tid)

static char *
thread_db_err_str (td_err_e err)
{
  static char buf[64];

  switch (err)
    {
    case TD_OK:
      return "generic 'call succeeded'";
    case TD_ERR:
      return "generic error";
    case TD_NOTHR:
      return "no thread to satisfy query";
    case TD_NOSV:
      return "no sync handle to satisfy query";
    case TD_NOLWP:
      return "no LWP to satisfy query";
    case TD_BADPH:
      return "invalid process handle";
    case TD_BADTH:
      return "invalid thread handle";
    case TD_BADSH:
      return "invalid synchronization handle";
    case TD_BADTA:
      return "invalid thread agent";
    case TD_BADKEY:
      return "invalid key";
    case TD_NOMSG:
      return "no event message for getmsg";
    case TD_NOFPREGS:
      return "FPU register set not available";
    case TD_NOLIBTHREAD:
      return "application not linked with libthread";
    case TD_NOEVENT:
      return "requested event is not supported";
    case TD_NOCAPAB:
      return "capability not available";
    case TD_DBERR:
      return "debugger service failed";
    case TD_NOAPLIC:
      return "operation not applicable to";
    case TD_NOTSD:
      return "no thread-specific data for this thread";
    case TD_MALLOC:
      return "malloc failed";
    case TD_PARTIALREG:
      return "only part of register set was written/read";
    case TD_NOXREGS:
      return "X register set not available for this thread";
    default:
      snprintf (buf, sizeof (buf), "unknown thread_db error '%d'", err);
      return buf;
    }
}

static char *
thread_db_state_str (td_thr_state_e state)
{
  static char buf[64];

  switch (state)
    {
    case TD_THR_STOPPED:
      return "stopped by debugger";
    case TD_THR_RUN:
      return "runnable";
    case TD_THR_ACTIVE:
      return "active";
    case TD_THR_ZOMBIE:
      return "zombie";
    case TD_THR_SLEEP:
      return "sleeping";
    case TD_THR_STOPPED_ASLEEP:
      return "stopped by debugger AND blocked";
    default:
      snprintf (buf, sizeof (buf), "unknown thread_db state %d", state);
      return buf;
    }
}

/* Convert LWP to user-level thread id. */
static ptid_t
thread_from_lwp (ptid_t ptid)
{
  td_thrinfo_t ti;
  td_thrhandle_t th;
  td_err_e err;

  gdb_assert (IS_LWP (ptid));

  if (fbsd_thread_active)
    {
      err = td_ta_map_lwp2thr_p (thread_agent, GET_LWP (ptid), &th);
      if (err == TD_OK)
        {
          err = td_thr_get_info_p (&th, &ti);
          if (err != TD_OK)
            error ("Cannot get thread info: %s", thread_db_err_str (err));
          return BUILD_THREAD (ti.ti_tid, GET_PID (ptid));
        }
    }

  /* the LWP is not mapped to user thread */
  return BUILD_LWP (GET_LWP (ptid), GET_PID (ptid));
}

static void
fbsd_core_get_first_lwp (bfd *abfd, asection *asect, void *obj)
{
  if (strncmp (bfd_section_name (abfd, asect), ".reg/", 5) != 0)
    return;

  if (*(lwpid_t *)obj != 0)
    return;

  *(lwpid_t *)obj = atoi (bfd_section_name (abfd, asect) + 5);
}

static long
get_current_lwp (int pid)
{
  struct ptrace_lwpinfo pl;
  lwpid_t lwpid;

  if (!target_has_execution)
    {
      lwpid = 0;
      bfd_map_over_sections (core_bfd, fbsd_core_get_first_lwp, &lwpid);
      return lwpid;
    }
  if (ptrace (PT_LWPINFO, pid, (caddr_t)&pl, sizeof(pl)))
    perror_with_name("PT_LWPINFO");

  return (long)pl.pl_lwpid;
}

static void
get_current_thread ()
{
  long lwp;
  ptid_t tmp, ptid;

  lwp = get_current_lwp (proc_handle.pid);
  tmp = BUILD_LWP (lwp, proc_handle.pid);
  ptid = thread_from_lwp (tmp);
  if (!in_thread_list (ptid))
    {
      add_thread (ptid);
      inferior_ptid = ptid;
    }
}

static void
fbsd_thread_activate (void)
{
  fbsd_thread_active = 1;
  init_thread_list();
  fbsd_thread_find_new_threads ();
  get_current_thread ();
}

static void
fbsd_thread_deactivate (void)
{
  td_ta_delete_p (thread_agent);

  inferior_ptid = pid_to_ptid (proc_handle.pid);
  proc_handle.pid = 0;
  fbsd_thread_active = 0;
  fbsd_thread_present = 0;
  init_thread_list ();
}

static void
fbsd_thread_new_objfile (struct objfile *objfile)
{
  td_err_e err;

  /* Don't attempt to use thread_db on targets which can not run
     (core files).  */
  if (objfile == NULL)
    {
      /* All symbols have been discarded.  If the thread_db target is
         active, deactivate it now.  */
      if (fbsd_thread_active)
        {
          gdb_assert (proc_handle.pid == 0);
          fbsd_thread_active = 0;
        }

      goto quit;
    }

  if (!child_suppress_run)
    goto quit;

  if (fbsd_thread_active)
    /* Nothing to do.  The thread library was already detected and the
       target vector was already activated.  */
    goto quit;

  /* Initialize the structure that identifies the child process.  Note
     that at this point there is no guarantee that we actually have a
     child process.  */
  proc_handle.pid = GET_PID (inferior_ptid);

  /* Now attempt to open a connection to the thread library.  */
  err = td_ta_new_p (&proc_handle, &thread_agent);
  switch (err)
    {
    case TD_NOLIBTHREAD:
      /* No thread library was detected.  */
      break;

    case TD_OK:
      /* The thread library was detected.  Activate the thread_db target.  */
      fbsd_thread_present = 1;

      /* We can only poke around if there actually is a child process.
         If there is no child process alive, postpone the steps below
         until one has been created.  */
      if (fbsd_thread_core == 0 && proc_handle.pid != 0)
        {
          push_target(&fbsd_thread_ops);
          fbsd_thread_activate();
        }
      else
        {
          td_ta_delete_p(thread_agent);
          thread_agent = NULL;
        }
      break;

    default:
      warning ("Cannot initialize thread debugging library: %s",
               thread_db_err_str (err));
      break;
    }

 quit:
  if (target_new_objfile_chain)
    target_new_objfile_chain (objfile);
}

static void
fbsd_thread_attach (char *args, int from_tty)
{
  fbsd_thread_core = 0;

  child_ops.to_attach (args, from_tty);

  /* Must get symbols from solibs before libthread_db can run! */
  SOLIB_ADD ((char *) 0, from_tty, (struct target_ops *) 0, auto_solib_add);

  if (fbsd_thread_present && !fbsd_thread_active)
    push_target(&fbsd_thread_ops);
}

static void
fbsd_thread_post_attach (int pid)
{
  child_ops.to_post_attach (pid);

  if (fbsd_thread_present && !fbsd_thread_active)
    {
      proc_handle.pid = GET_PID (inferior_ptid);
      fbsd_thread_activate ();
    }
}

static void
fbsd_thread_detach (char *args, int from_tty)
{
  fbsd_thread_deactivate ();
  unpush_target (&fbsd_thread_ops);

  /* Clear gdb solib information and symbol file
     cache, so that after detach and re-attach, new_objfile
     hook will be called */

  clear_solib();
  symbol_file_clear(0);
  proc_handle.pid = 0;
  child_ops.to_detach (args, from_tty);
}

static int
suspend_thread_callback (const td_thrhandle_t *th_p, void *data)
{
  int err = td_thr_dbsuspend_p (th_p);
  if (err != 0)
	fprintf_filtered(gdb_stderr, "%s %s\n", __func__, thread_db_err_str (err));
  return (err);
}

static int
resume_thread_callback (const td_thrhandle_t *th_p, void *data)
{
  int err = td_thr_dbresume_p (th_p);
  if (err != 0)
	fprintf_filtered(gdb_stderr, "%s %s\n", __func__, thread_db_err_str (err));
  return (err);
}

static void
fbsd_thread_resume (ptid_t ptid, int step, enum target_signal signo)
{
  td_thrhandle_t th;
  td_thrinfo_t ti;
  ptid_t work_ptid;
  int resume_all, ret;
  long lwp, thvalid = 0;

  if (!fbsd_thread_active)
    {
      child_ops.to_resume (ptid, step, signo);
      return;
    }

  if (GET_PID(ptid) != -1 && step != 0)
    {
      resume_all = 0;
      work_ptid = ptid;
    }
  else
    {
      resume_all = 1;
      work_ptid = inferior_ptid;
    }

  lwp = GET_LWP (work_ptid);
  if (lwp == 0)
    {
      /* check user thread */
      ret = td_ta_map_id2thr_p (thread_agent, GET_THREAD(work_ptid), &th);
      if (ret)
        error (thread_db_err_str (ret));

      /*
       * For M:N thread, we need to tell UTS to set/unset single step
       * flag at context switch time, the flag will be written into
       * thread mailbox. This becauses some architecture may not have
       * machine single step flag in ucontext, so we put the flag in mailbox,
       * when the thread switches back, kse_switchin restores the single step
       * state.
       */
      ret = td_thr_sstep_p (&th, step);
      if (ret)
        error (thread_db_err_str (ret));
      ret = td_thr_get_info_p (&th, &ti);
      if (ret)
        error (thread_db_err_str (ret));
      thvalid = 1;
      lwp = ti.ti_lid;
    }

  if (lwp)
    {
      int req = step ? PT_SETSTEP : PT_CLEARSTEP;
      if (ptrace (req, (pid_t) lwp, (caddr_t) 1, target_signal_to_host(signo)))
        perror_with_name ("PT_SETSTEP/PT_CLEARSTEP");
    }

  if (!ptid_equal (last_single_step_thread, null_ptid))
    {
       ret = td_ta_thr_iter_p (thread_agent, resume_thread_callback, NULL,
          TD_THR_ANY_STATE, TD_THR_LOWEST_PRIORITY,
          TD_SIGNO_MASK, TD_THR_ANY_USER_FLAGS);
      if (ret != TD_OK)
        error ("resume error: %s", thread_db_err_str (ret));
    }

  if (!resume_all)
    {
      ret = td_ta_thr_iter_p (thread_agent, suspend_thread_callback, NULL,
          TD_THR_ANY_STATE, TD_THR_LOWEST_PRIORITY,
          TD_SIGNO_MASK, TD_THR_ANY_USER_FLAGS);
      if (ret != TD_OK)
        error ("suspend error: %s", thread_db_err_str (ret));
      last_single_step_thread = work_ptid;
    }
  else
    last_single_step_thread = null_ptid;

  if (thvalid)
    {
      ret = td_thr_dbresume_p (&th);
      if (ret != TD_OK)
        error ("resume error: %s", thread_db_err_str (ret));
    }
  else
    {
      /* it is not necessary, put it here for completness */
      ret = ptrace(PT_RESUME, lwp, 0, 0);
    }

  /* now continue the process, suspended thread wont run */
  if (ptrace (PT_CONTINUE, proc_handle.pid , (caddr_t)1,
	      target_signal_to_host(signo)))
    perror_with_name ("PT_CONTINUE");
}

static ptid_t
fbsd_thread_wait (ptid_t ptid, struct target_waitstatus *ourstatus)
{
  ptid_t ret;
  long lwp;
  CORE_ADDR stop_pc;

  ret = child_ops.to_wait (ptid, ourstatus);
  if (GET_PID(ret) >= 0 && ourstatus->kind == TARGET_WAITKIND_STOPPED)
    {
      lwp = get_current_lwp (GET_PID(ret));
      ret = thread_from_lwp (BUILD_LWP (lwp, GET_PID (ret)));
      if (!in_thread_list (ret))
        add_thread (ret);
      /* this is a hack, if an event won't cause gdb to stop, for example,
         SIGARLM, gdb resumes the process immediatly without setting
         inferior_ptid to the new thread returned here, this is a bug
         because inferior_ptid may already not exist there, and passing
         a none existing thread to fbsd_thread_resume causes error. */
      if (!fbsd_thread_alive (inferior_ptid))
        {
          delete_thread (inferior_ptid);
          inferior_ptid = ret;
       }
    }

  return (ret);
}

static int
fbsd_thread_xfer_memory (CORE_ADDR memaddr, char *myaddr, int len, int write,
                        struct mem_attrib *attrib, struct target_ops *target)
{
  int err;

  if (target_has_execution)
    err = child_ops.to_xfer_memory (memaddr, myaddr, len, write, attrib,
	target);
  else
    err = orig_core_ops.to_xfer_memory (memaddr, myaddr, len, write, attrib,
	target);

  return (err);
}

static void
fbsd_lwp_fetch_registers (int regno)
{
  gregset_t gregs;
  fpregset_t fpregs;
  lwpid_t lwp;

  if (!target_has_execution)
    {
      orig_core_ops.to_fetch_registers (-1);
      return;
    }

  lwp = GET_LWP (inferior_ptid);

  if (ptrace (PT_GETREGS, lwp, (caddr_t) &gregs, 0) == -1)
    error ("Cannot get lwp %d registers: %s\n", lwp, safe_strerror (errno));
  supply_gregset (&gregs);

  if (ptrace (PT_GETFPREGS, lwp, (caddr_t) &fpregs, 0) == -1)
    error ("Cannot get lwp %d registers: %s\n ", lwp, safe_strerror (errno));

  supply_fpregset (&fpregs);
}

static void
fbsd_thread_fetch_registers (int regno)
{
  prgregset_t gregset;
  prfpregset_t fpregset;
  td_thrhandle_t th;
  td_err_e err;

  if (!IS_THREAD (inferior_ptid))
    {
      fbsd_lwp_fetch_registers (regno);
      return;
    }

  err = td_ta_map_id2thr_p (thread_agent, GET_THREAD (inferior_ptid), &th);
  if (err != TD_OK)
    error ("Cannot find thread %d: Thread ID=%ld, %s",
           pid_to_thread_id (inferior_ptid),
           GET_THREAD (inferior_ptid), thread_db_err_str (err));

  err = td_thr_getgregs_p (&th, gregset);
  if (err != TD_OK)
    error ("Cannot fetch general-purpose registers for thread %d: Thread ID=%ld, %s",
           pid_to_thread_id (inferior_ptid),
           GET_THREAD (inferior_ptid), thread_db_err_str (err));

  err = td_thr_getfpregs_p (&th, &fpregset);
  if (err != TD_OK)
    error ("Cannot get floating-point registers for thread %d: Thread ID=%ld, %s",
           pid_to_thread_id (inferior_ptid),
           GET_THREAD (inferior_ptid), thread_db_err_str (err));

  supply_gregset (gregset);
  supply_fpregset (&fpregset);
}

static void
fbsd_lwp_store_registers (int regno)
{
  gregset_t gregs;
  fpregset_t fpregs;
  lwpid_t lwp;

  /* FIXME, is it possible ? */
  if (!IS_LWP (inferior_ptid))
    {
      child_ops.to_store_registers (regno);
      return ;
    }

  lwp = GET_LWP (inferior_ptid);
  if (regno != -1)
    if (ptrace (PT_GETREGS, lwp, (caddr_t) &gregs, 0) == -1)
      error ("Cannot get lwp %d registers: %s\n", lwp, safe_strerror (errno));

  fill_gregset (&gregs, regno);
  if (ptrace (PT_SETREGS, lwp, (caddr_t) &gregs, 0) == -1)
      error ("Cannot set lwp %d registers: %s\n", lwp, safe_strerror (errno));

  if (regno != -1)
    if (ptrace (PT_GETFPREGS, lwp, (caddr_t) &fpregs, 0) == -1)
      error ("Cannot get lwp %d float registers: %s\n", lwp,
             safe_strerror (errno));

  fill_fpregset (&fpregs, regno);
  if (ptrace (PT_SETFPREGS, lwp, (caddr_t) &fpregs, 0) == -1)
     error ("Cannot set lwp %d float registers: %s\n", lwp,
            safe_strerror (errno));
}

static void
fbsd_thread_store_registers (int regno)
{
  prgregset_t gregset;
  prfpregset_t fpregset;
  td_thrhandle_t th;
  td_err_e err;

  if (!IS_THREAD (inferior_ptid))
    {
      fbsd_lwp_store_registers (regno);
      return;
    }

  err = td_ta_map_id2thr_p (thread_agent, GET_THREAD (inferior_ptid), &th);
  if (err != TD_OK)
    error ("Cannot find thread %d: Thread ID=%ld, %s",
           pid_to_thread_id (inferior_ptid),
           GET_THREAD (inferior_ptid),
           thread_db_err_str (err));

  if (regno != -1)
    {
      char old_value[MAX_REGISTER_SIZE];

      regcache_collect (regno, old_value);
      err = td_thr_getgregs_p (&th, gregset);
      if (err != TD_OK)
        error ("%s: td_thr_getgregs %s", __func__, thread_db_err_str (err));
      err = td_thr_getfpregs_p (&th, &fpregset);
      if (err != TD_OK)
        error ("%s: td_thr_getfpgregs %s", __func__, thread_db_err_str (err));
      supply_register (regno, old_value);
    }

  fill_gregset (gregset, regno);
  fill_fpregset (&fpregset, regno);

  err = td_thr_setgregs_p (&th, gregset);
  if (err != TD_OK)
    error ("Cannot store general-purpose registers for thread %d: Thread ID=%d, %s",
           pid_to_thread_id (inferior_ptid), GET_THREAD (inferior_ptid),
           thread_db_err_str (err));
  err = td_thr_setfpregs_p (&th, &fpregset);
  if (err != TD_OK)
    error ("Cannot store floating-point registers for thread %d: Thread ID=%d, %s",
           pid_to_thread_id (inferior_ptid), GET_THREAD (inferior_ptid),
           thread_db_err_str (err));
}

static void
fbsd_thread_kill (void)
{
  child_ops.to_kill();
}

static int
fbsd_thread_can_run (void)
{
  return child_suppress_run;
}

static void
fbsd_thread_create_inferior (char *exec_file, char *allargs, char **env)
{
  if (fbsd_thread_present && !fbsd_thread_active)
    push_target(&fbsd_thread_ops);

  child_ops.to_create_inferior (exec_file, allargs, env);
}

static void
fbsd_thread_post_startup_inferior (ptid_t ptid)
{
  if (fbsd_thread_present && !fbsd_thread_active)
    {
      /*
       * The child process is now the actual multi-threaded
       * program.  Snatch its process ID...
       */
      proc_handle.pid = GET_PID (ptid);
      td_ta_new_p (&proc_handle, &thread_agent);
      fbsd_thread_activate();
    }
}

static void
fbsd_thread_mourn_inferior (void)
{
  /*
   * Forget about the child's process ID.  We shouldn't need it
   * anymore.
   */
  if (fbsd_thread_active)
    fbsd_thread_deactivate ();

  unpush_target (&fbsd_thread_ops);

  child_ops.to_mourn_inferior ();
}

static void
fbsd_core_check_lwp (bfd *abfd, asection *asect, void *obj)
{
  lwpid_t lwp;

  if (strncmp (bfd_section_name (abfd, asect), ".reg/", 5) != 0)
    return;

  /* already found */
  if (*(lwpid_t *)obj == 0)
    return;

  lwp = atoi (bfd_section_name (abfd, asect) + 5);
  if (*(lwpid_t *)obj == lwp)
    *(lwpid_t *)obj = 0;
}

static int
fbsd_thread_alive (ptid_t ptid)
{
  td_thrhandle_t th;
  td_thrinfo_t ti;
  td_err_e err;
  gregset_t gregs;
  lwpid_t lwp;

  if (IS_THREAD (ptid))
    {
      err = td_ta_map_id2thr_p (thread_agent, GET_THREAD (ptid), &th);
      if (err != TD_OK)
        return 0;

      err = td_thr_get_info_p (&th, &ti);
      if (err != TD_OK)
        return 0;

      /* A zombie thread. */
      if (ti.ti_state == TD_THR_UNKNOWN || ti.ti_state == TD_THR_ZOMBIE)
        return 0;

      return 1;
    }
  else if (GET_LWP (ptid) == 0)
    {
      /* we sometimes are called with lwp == 0 */
      return 1;
    }

  if (fbsd_thread_active)
    {
      err = td_ta_map_lwp2thr_p (thread_agent, GET_LWP (ptid), &th);

      /*
       * if the lwp was already mapped to user thread, don't use it
       * directly, please use user thread id instead.
       */
      if (err == TD_OK)
        return 0;
    }

  if (!target_has_execution)
    {
      lwp = GET_LWP (ptid);
      bfd_map_over_sections (core_bfd, fbsd_core_check_lwp, &lwp);
      return (lwp == 0);
    }

  /* check lwp in kernel */
  return ptrace (PT_GETREGS, GET_LWP (ptid), (caddr_t)&gregs, 0) == 0;
}

static void
fbsd_thread_files_info (struct target_ops *ignore)
{
  child_ops.to_files_info (ignore);
}

static int
find_new_threads_callback (const td_thrhandle_t *th_p, void *data)
{
  td_thrinfo_t ti;
  td_err_e err;
  ptid_t ptid;

  err = td_thr_get_info_p (th_p, &ti);
  if (err != TD_OK)
    error ("Cannot get thread info: %s", thread_db_err_str (err));

  /* Ignore zombie */
  if (ti.ti_state == TD_THR_UNKNOWN || ti.ti_state == TD_THR_ZOMBIE)
    return 0;

  ptid = BUILD_THREAD (ti.ti_tid, proc_handle.pid);

  if (!in_thread_list (ptid))
      add_thread (ptid);
  return 0;
}

static void
fbsd_thread_find_new_threads (void)
{
  td_err_e err;

  if (!fbsd_thread_active)
    return;

  /* Iterate over all user-space threads to discover new threads. */
  err = td_ta_thr_iter_p (thread_agent, find_new_threads_callback, NULL,
          TD_THR_ANY_STATE, TD_THR_LOWEST_PRIORITY,
          TD_SIGNO_MASK, TD_THR_ANY_USER_FLAGS);
  if (err != TD_OK)
    error ("Cannot find new threads: %s", thread_db_err_str (err));
}

static char *
fbsd_thread_pid_to_str (ptid_t ptid)
{
  static char buf[64];

  if (IS_THREAD (ptid))
    {
      td_thrhandle_t th;
      td_thrinfo_t ti;
      td_err_e err;

      err = td_ta_map_id2thr_p (thread_agent, GET_THREAD (ptid), &th);
      if (err != TD_OK)
        error ("Cannot find thread, Thread ID=%ld, %s",
                GET_THREAD (ptid), thread_db_err_str (err));

      err = td_thr_get_info_p (&th, &ti);
      if (err != TD_OK)
        error ("Cannot get thread info, Thread ID=%ld, %s",
               GET_THREAD (ptid), thread_db_err_str (err));

      if (ti.ti_lid != 0)
        {
          snprintf (buf, sizeof (buf), "Thread %ld (LWP %d)",
                    GET_THREAD (ptid), ti.ti_lid);
        }
      else
        {
          snprintf (buf, sizeof (buf), "Thread %ld (%s)",
                    GET_THREAD (ptid), thread_db_state_str (ti.ti_state));
        }

      return buf;
    }
  else if (IS_LWP (ptid))
    {
      snprintf (buf, sizeof (buf), "LWP %d", (int) GET_LWP (ptid));
      return buf;
    }
  return normal_pid_to_str (ptid);
}

CORE_ADDR
fbsd_thread_get_local_address(ptid_t ptid, struct objfile *objfile,
                              CORE_ADDR offset)
{
  td_thrhandle_t th;
  void *address;
  CORE_ADDR lm;
  int ret, is_library = (objfile->flags & OBJF_SHARED);

  if (IS_THREAD (ptid))
    {
      if (!td_thr_tls_get_addr_p)
        error ("Cannot find thread-local interface in thread_db library.");

      /* Get the address of the link map for this objfile. */
      lm = svr4_fetch_objfile_link_map (objfile);

      /* Couldn't find link map. Bail out. */
      if (!lm)
        {
          if (is_library)
            error ("Cannot find shared library `%s' link_map in dynamic"
                   " linker's module list", objfile->name);
          else
            error ("Cannot find executable file `%s' link_map in dynamic"
                   " linker's module list", objfile->name);
        }

      ret = td_ta_map_id2thr_p (thread_agent, GET_THREAD(ptid), &th);

      /* get the address of the variable. */
      ret = td_thr_tls_get_addr_p (&th, (void *) lm, offset, &address);

      if (ret != TD_OK)
        {
          if (is_library)
            error ("Cannot find thread-local storage for thread %ld, "
                   "shared library %s:\n%s",
                   (long) GET_THREAD (ptid),
                   objfile->name, thread_db_err_str (ret));
          else
            error ("Cannot find thread-local storage for thread %ld, "
                   "executable file %s:\n%s",
                   (long) GET_THREAD (ptid),
                   objfile->name, thread_db_err_str (ret));
        }

      /* Cast assuming host == target. */
      return (CORE_ADDR) address;
    }
  return (0);
}

static int
tsd_cb (thread_key_t key, void (*destructor)(void *), void *ignore)
{
  struct minimal_symbol *ms;
  char *name;

  ms = lookup_minimal_symbol_by_pc ((CORE_ADDR)destructor);
  if (!ms)
    name = "???";
  else
    name = DEPRECATED_SYMBOL_NAME (ms);

  printf_filtered ("Destructor %p <%s>\n", destructor, name);
  return 0;
}

static void
fbsd_thread_tsd_cmd (char *exp, int from_tty)
{
  if (fbsd_thread_active)
    td_ta_tsd_iter_p (thread_agent, tsd_cb, NULL);
}

static int
ignore (CORE_ADDR addr, char *contents)
{
  return 0;
}

static void
fbsd_core_open (char *filename, int from_tty)
{
  int err;

  fbsd_thread_core = 1;

  orig_core_ops.to_open (filename, from_tty);

  if (fbsd_thread_present)
    {
      err = td_ta_new_p (&proc_handle, &thread_agent);
      if (err == TD_OK)
        {
          proc_handle.pid = elf_tdata (core_bfd)->core_pid;
          fbsd_thread_activate ();
        }
      else
        error ("fbsd_core_open: td_ta_new: %s", thread_db_err_str (err));
    }
}

static void
fbsd_core_close (int quitting)
{
  orig_core_ops.to_close (quitting);
}

static void
fbsd_core_detach (char *args, int from_tty)
{
  if (fbsd_thread_active)
    fbsd_thread_deactivate ();
  unpush_target (&fbsd_thread_ops);
  orig_core_ops.to_detach (args, from_tty);

  /* Clear gdb solib information and symbol file
     cache, so that after detach and re-attach, new_objfile
     hook will be called */
  clear_solib();
  symbol_file_clear(0);
}

static void
fbsd_core_files_info (struct target_ops *ignore)
{
  orig_core_ops.to_files_info (ignore);
}

static void
init_fbsd_core_ops (void)
{
  fbsd_core_ops.to_shortname = "FreeBSD-core";
  fbsd_core_ops.to_longname = "FreeBSD core thread.";
  fbsd_core_ops.to_doc = "FreeBSD threads support for core files.";
  fbsd_core_ops.to_open = fbsd_core_open;
  fbsd_core_ops.to_close = fbsd_core_close;
  fbsd_core_ops.to_attach = 0;
  fbsd_core_ops.to_post_attach = 0;
  fbsd_core_ops.to_detach = fbsd_core_detach;
  /* fbsd_core_ops.to_resume  = 0; */
  /* fbsd_core_ops.to_wait  = 0;  */
  fbsd_core_ops.to_fetch_registers = fbsd_thread_fetch_registers;
  /* fbsd_core_ops.to_store_registers  = 0; */
  /* fbsd_core_ops.to_prepare_to_store  = 0; */
  fbsd_core_ops.to_xfer_memory = fbsd_thread_xfer_memory;
  fbsd_core_ops.to_files_info = fbsd_core_files_info;
  fbsd_core_ops.to_insert_breakpoint = ignore;
  fbsd_core_ops.to_remove_breakpoint = ignore;
  /* fbsd_core_ops.to_lookup_symbol  = 0; */
  fbsd_core_ops.to_create_inferior = fbsd_thread_create_inferior;
  fbsd_core_ops.to_stratum = core_stratum;
  fbsd_core_ops.to_has_all_memory = 0;
  fbsd_core_ops.to_has_memory = 1;
  fbsd_core_ops.to_has_stack = 1;
  fbsd_core_ops.to_has_registers = 1;
  fbsd_core_ops.to_has_execution = 0;
  fbsd_core_ops.to_has_thread_control = tc_none;
  fbsd_core_ops.to_thread_alive = fbsd_thread_alive;
  fbsd_core_ops.to_pid_to_str = fbsd_thread_pid_to_str;
  fbsd_core_ops.to_find_new_threads = fbsd_thread_find_new_threads;
  fbsd_core_ops.to_sections = 0;
  fbsd_core_ops.to_sections_end = 0;
  fbsd_core_ops.to_magic = OPS_MAGIC;
}

static void
init_fbsd_thread_ops (void)
{
  fbsd_thread_ops.to_shortname = "freebsd-threads";
  fbsd_thread_ops.to_longname = "FreeBSD multithreaded child process.";
  fbsd_thread_ops.to_doc = "FreeBSD threads support.";
  fbsd_thread_ops.to_attach = fbsd_thread_attach;
  fbsd_thread_ops.to_detach = fbsd_thread_detach;
  fbsd_thread_ops.to_post_attach = fbsd_thread_post_attach;
  fbsd_thread_ops.to_resume = fbsd_thread_resume;
  fbsd_thread_ops.to_wait = fbsd_thread_wait;
  fbsd_thread_ops.to_fetch_registers = fbsd_thread_fetch_registers;
  fbsd_thread_ops.to_store_registers = fbsd_thread_store_registers;
  fbsd_thread_ops.to_xfer_memory = fbsd_thread_xfer_memory;
  fbsd_thread_ops.to_files_info = fbsd_thread_files_info;
  fbsd_thread_ops.to_kill = fbsd_thread_kill;
  fbsd_thread_ops.to_create_inferior = fbsd_thread_create_inferior;
  fbsd_thread_ops.to_post_startup_inferior = fbsd_thread_post_startup_inferior;
  fbsd_thread_ops.to_mourn_inferior = fbsd_thread_mourn_inferior;
  fbsd_thread_ops.to_can_run = fbsd_thread_can_run;
  fbsd_thread_ops.to_thread_alive = fbsd_thread_alive;
  fbsd_thread_ops.to_find_new_threads = fbsd_thread_find_new_threads;
  fbsd_thread_ops.to_pid_to_str = fbsd_thread_pid_to_str;
  fbsd_thread_ops.to_stratum = thread_stratum;
  fbsd_thread_ops.to_has_thread_control = tc_none;
  fbsd_thread_ops.to_has_all_memory = 1;
  fbsd_thread_ops.to_has_memory = 1;
  fbsd_thread_ops.to_has_stack = 1;
  fbsd_thread_ops.to_has_registers = 1;
  fbsd_thread_ops.to_has_execution = 1;
  fbsd_thread_ops.to_insert_breakpoint = memory_insert_breakpoint;
  fbsd_thread_ops.to_remove_breakpoint = memory_remove_breakpoint;
  fbsd_thread_ops.to_get_thread_local_address = fbsd_thread_get_local_address;
  fbsd_thread_ops.to_magic = OPS_MAGIC;
}

static int
thread_db_load (void)
{
  void *handle;
  td_err_e err;

  handle = dlopen (LIBTHREAD_DB_SO, RTLD_NOW);
  if (handle == NULL)
      return 0;

#define resolve(X)			\
 if (!(X##_p = dlsym (handle, #X)))	\
   return 0;

  resolve(td_init);
  resolve(td_ta_new);
  resolve(td_ta_delete);
  resolve(td_ta_map_id2thr);
  resolve(td_ta_map_lwp2thr);
  resolve(td_ta_thr_iter);
  resolve(td_thr_get_info);
  resolve(td_thr_getfpregs);
  resolve(td_thr_getgregs);
  resolve(td_thr_setfpregs);
  resolve(td_thr_setgregs);
  resolve(td_thr_sstep);
  resolve(td_ta_tsd_iter);
  resolve(td_thr_dbsuspend);
  resolve(td_thr_dbresume);
  resolve(td_thr_tls_get_addr);

  /* Initialize the library.  */
  err = td_init_p ();
  if (err != TD_OK)
    {
      warning ("Cannot initialize libthread_db: %s", thread_db_err_str (err));
      return 0;
    }

  return 1;
}

/* we suppress the call to add_target of core_ops in corelow because
   if there are two targets in the stratum core_stratum, find_core_target
   won't know which one to return.  see corelow.c for an additonal
   comment on coreops_suppress_target. */

int coreops_suppress_target = 1;

void
_initialize_thread_db (void)
{
  init_fbsd_thread_ops ();
  init_fbsd_core_ops ();

  if (thread_db_load ())
    {
      add_target (&fbsd_thread_ops);

      /* "thread tsd" command */
      add_cmd ("tsd", class_run, fbsd_thread_tsd_cmd,
            "Show the thread-specific data keys and destructors "
            "for the process.\n",
           &thread_cmd_list);

      memcpy (&orig_core_ops, &core_ops, sizeof (struct target_ops));
      memcpy (&core_ops, &fbsd_core_ops, sizeof (struct target_ops));
      add_target (&core_ops);

      /* Add ourselves to objfile event chain. */
      target_new_objfile_chain = target_new_objfile_hook;
      target_new_objfile_hook = fbsd_thread_new_objfile;

      child_suppress_run = 1;
    }
  else
    {
      fprintf_unfiltered (gdb_stderr,
        "[GDB will not be able to debug user-mode threads: %s]\n", dlerror());

      /* allow the user to debug non-threaded core files */
      add_target (&core_ops);
    }
}

/* proc service functions */
void
ps_plog (const char *fmt, ...)
{
  va_list args;

  va_start (args, fmt);
  vfprintf_filtered (gdb_stderr, fmt, args);
  va_end (args);
}

ps_err_e
ps_pglobal_lookup (struct ps_prochandle *ph, const char *obj,
   const char *name, psaddr_t *sym_addr)
{
  struct minimal_symbol *ms;

  ms = lookup_minimal_symbol (name, NULL, NULL);
  if (ms == NULL)
    return PS_NOSYM;

  *sym_addr = (psaddr_t) SYMBOL_VALUE_ADDRESS (ms);
  return PS_OK;
}

ps_err_e
ps_pread (struct ps_prochandle *ph, psaddr_t addr, void *buf, size_t len)
{
  int err = target_read_memory ((CORE_ADDR) addr, buf, len);
  return (err == 0 ? PS_OK : PS_ERR);
}

ps_err_e
ps_pwrite (struct ps_prochandle *ph, psaddr_t addr, const void *buf,
            size_t len)
{
  int err = target_write_memory ((CORE_ADDR) addr, (void *)buf, len);
  return (err == 0 ? PS_OK : PS_ERR);
}

ps_err_e
ps_lgetregs (struct ps_prochandle *ph, lwpid_t lwpid, prgregset_t gregset)
{
  struct cleanup *old_chain;

  old_chain = save_inferior_ptid ();
  inferior_ptid = BUILD_LWP (lwpid, PIDGET (inferior_ptid));
  target_fetch_registers (-1);
  fill_gregset (gregset, -1);
  do_cleanups (old_chain);
  return PS_OK;
}

ps_err_e
ps_lsetregs (struct ps_prochandle *ph, lwpid_t lwpid, const prgregset_t gregset)
{
  struct cleanup *old_chain;

  old_chain = save_inferior_ptid ();
  inferior_ptid = BUILD_LWP (lwpid, PIDGET (inferior_ptid));
  supply_gregset (gregset);
  target_store_registers (-1);
  do_cleanups (old_chain);
  return PS_OK;
}

ps_err_e
ps_lgetfpregs (struct ps_prochandle *ph, lwpid_t lwpid, prfpregset_t *fpregset)
{
  struct cleanup *old_chain;

  old_chain = save_inferior_ptid ();
  inferior_ptid = BUILD_LWP (lwpid, PIDGET (inferior_ptid));
  target_fetch_registers (-1);
  fill_fpregset (fpregset, -1);
  do_cleanups (old_chain);
  return PS_OK;
}

ps_err_e
ps_lsetfpregs (struct ps_prochandle *ph, lwpid_t lwpid,
               const prfpregset_t *fpregset)
{
  struct cleanup *old_chain;

  old_chain = save_inferior_ptid ();
  inferior_ptid = BUILD_LWP (lwpid, PIDGET (inferior_ptid));
  supply_fpregset (fpregset);
  target_store_registers (-1);
  do_cleanups (old_chain);
  return PS_OK;
}

ps_err_e
ps_lstop(struct ps_prochandle *ph, lwpid_t lwpid)
{
  if (ptrace (PT_SUSPEND, lwpid, 0, 0) == -1)
    return PS_ERR;
  return PS_OK;
}

ps_err_e
ps_lcontinue(struct ps_prochandle *ph, lwpid_t lwpid)
{
  if (ptrace (PT_RESUME, lwpid, 0, 0) == -1)
    return PS_ERR;
  return PS_OK;
}