binutils-gdb/gdb/dec-thread.c

/* Copyright (C) 2008-2014 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"
#include "command.h"
#include "gdbcmd.h"
#include "target.h"
#include "observer.h"
#include <sys/procfs.h>
#include "gregset.h"
#include "regcache.h"
#include "inferior.h"
#include "gdbthread.h"

#include <pthread_debug.h>

/* Print debugging traces if set to non-zero.  */
static int debug_dec_thread = 0;

/* Non-zero if the dec-thread layer is active.  */
static int dec_thread_active = 0;

/* The pthread_debug context.  */
pthreadDebugContext_t debug_context;

/* The dec-thread target_ops structure.  */
static struct target_ops dec_thread_ops;

/* Print a debug trace if DEBUG_DEC_THREAD is set (its value is adjusted
   by the user using "set debug dec-thread ...").  */

static void
debug (char *format, ...)
{
  if (debug_dec_thread)
    {
      va_list args;

      va_start (args, format);
      printf_unfiltered ("DEC Threads: ");
      vprintf_unfiltered (format, args);
      printf_unfiltered ("\n");
      va_end (args);
    }
}

/* pthread debug callbacks.  */

static int
suspend_clbk (void *caller_context)
{
  return ESUCCESS;
}

static int
resume_clbk (void *caller_context)
{
  return ESUCCESS;
} 

static int
hold_clbk (void *caller_context, pthreadDebugKId_t kernel_tid)
{ 
  return ESUCCESS;
}

static int
unhold_clbk (void *caller_context, pthreadDebugKId_t kernel_tid)
{
  return ESUCCESS;
}

static int
read_clbk (void *caller_context, void *address, void *buffer,
           unsigned long size)
{
  int status = target_read_memory ((CORE_ADDR) address, buffer, size);

  if (status != 0)
    return EINVAL;

  return ESUCCESS;
}

static int
write_clbk (void *caller_context, void *address, void *buffer,
            unsigned long size)
{
  int status = target_write_memory ((CORE_ADDR) address, buffer, size);
  
  if (status != 0)
    return EINVAL;

  return ESUCCESS;
}

/* Get integer regs.  */

static int
get_reg_clbk(void *caller_context, pthreadDebugGetRegRtn_t regs,
             pthreadDebugKId_t kernel_tid)
{
  debug ("get_reg_clbk");

  /* Not sure that we actually need to do anything in this callback.  */
  return ESUCCESS;
}

/* Set integer regs.  */

static int
set_reg_clbk(void *caller_context, const pthreadDebugRegs_t *regs,
             pthreadDebugKId_t kernel_tid)
{
  debug ("set_reg_clbk");

  /* Not sure that we actually need to do anything in this callback.  */
  return ESUCCESS;
}

static int
output_clbk (void *caller_context, char *line)
{
  printf_filtered ("%s\n", line);
  return ESUCCESS;
}

static int
error_clbk (void *caller_context, char *line)
{
  fprintf_filtered (gdb_stderr, "%s\n", line);
  return ESUCCESS;
}

/* Get floating-point regs.  */

static int
get_fpreg_clbk (void *caller_context, pthreadDebugFregs_p fregs,
                pthreadDebugKId_t kernel_tid)
{
  debug ("get_fpreg_clbk");

  /* Not sure that we actually need to do anything in this callback.  */
  return ESUCCESS;
}

/* Set floating-point regs.  */

static int
set_fpreg_clbk (void *caller_context, const pthreadDebugFregs_t *fregs,
                pthreadDebugKId_t kernel_tid)
{
  debug ("set_fpreg_clbk");

  /* Not sure that we actually need to do anything in this callback.  */
  return ESUCCESS;
}

static void *
malloc_clbk (void *caller_context, size_t size)
{
  return xmalloc (size);
}

static void
free_clbk (void *caller_context, void *address)
{
  xfree (address);
}

static int
kthdinfo_clbk (pthreadDebugClient_t caller_context,
               pthreadDebugKId_t kernel_tid,
               pthreadDebugKThreadInfo_p thread_info)
{
  return ENOTSUP;
}

static int
speckthd_clbk (pthreadDebugClient_t caller_context,
               pthreadDebugSpecialType_t type,
               pthreadDebugKId_t *kernel_tid)
{
  return ENOTSUP;
}

static pthreadDebugCallbacks_t debug_callbacks =
{
  PTHREAD_DEBUG_VERSION,
  (pthreadDebugGetMemRtn_t) read_clbk,
  (pthreadDebugSetMemRtn_t) write_clbk,
  suspend_clbk,
  resume_clbk,
  kthdinfo_clbk,
  hold_clbk,
  unhold_clbk,
  (pthreadDebugGetFregRtn_t) get_fpreg_clbk,
  (pthreadDebugSetFregRtn_t) set_fpreg_clbk,
  (pthreadDebugGetRegRtn_t) get_reg_clbk,
  (pthreadDebugSetRegRtn_t) set_reg_clbk,
  (pthreadDebugOutputRtn_t) output_clbk,
  (pthreadDebugOutputRtn_t) error_clbk,
  malloc_clbk,
  free_clbk,
  speckthd_clbk
};

/* Activate thread support if appropriate.  Do nothing if thread
   support is already active.  */

static void
enable_dec_thread (void)
{
  struct bound_minimal_symbol msym;
  void* caller_context;
  int status;

  /* If already active, nothing more to do.  */
  if (dec_thread_active)
    return;

  msym = lookup_minimal_symbol ("__pthread_dbg_symtable", NULL, NULL);
  if (msym.minsym == NULL)
    {
      debug ("enable_dec_thread: No __pthread_dbg_symtable");
      return;
    }

  status = pthreadDebugContextInit (&caller_context, &debug_callbacks,
                                    (void *) SYMBOL_VALUE_ADDRESS (msym.minsym),
                                    &debug_context);
  if (status != ESUCCESS)
    {
      debug ("enable_dec_thread: pthreadDebugContextInit -> %d",
             status);
      return;
    }

  push_target (&dec_thread_ops);
  dec_thread_active = 1;

  debug ("enable_dec_thread: Thread support enabled.");
}

/* Deactivate thread support.  Do nothing if thread support is
   already inactive.  */

static void
disable_dec_thread (void)
{
  if (!dec_thread_active)
    return;

  pthreadDebugContextDestroy (debug_context);
  unpush_target (&dec_thread_ops);
  dec_thread_active = 0;
}

/* A structure that contains a thread ID and is associated
   pthreadDebugThreadInfo_t data.  */

struct dec_thread_info
{
  pthreadDebugId_t thread;
  pthreadDebugThreadInfo_t info;
};
typedef struct dec_thread_info dec_thread_info_s;

/* The list of user threads.  */

DEF_VEC_O (dec_thread_info_s);
VEC(dec_thread_info_s) *dec_thread_list;

/* Release the memory used by the given VECP thread list pointer.
   Then set *VECP to NULL.  */

static void
free_dec_thread_info_vec (VEC(dec_thread_info_s) **vecp)
{
  int i;
  struct dec_thread_info *item;
  VEC(dec_thread_info_s) *vec = *vecp;

  for (i = 0; VEC_iterate (dec_thread_info_s, vec, i, item); i++)
     xfree (item);
  VEC_free (dec_thread_info_s, vec);
  *vecp = NULL;
}

/* Return a thread's ptid given its associated INFO.  */

static ptid_t
ptid_build_from_info (struct dec_thread_info info)
{
  int pid = ptid_get_pid (inferior_ptid);

  return ptid_build (pid, 0, (long) info.thread);
}

/* Return non-zero if PTID is still alive.

   Assumes that DEC_THREAD_LIST is up to date.  */
static int
dec_thread_ptid_is_alive (ptid_t ptid)
{
  pthreadDebugId_t tid = ptid_get_tid (ptid);
  int i;
  struct dec_thread_info *info;

  if (tid == 0)
    /* This is the thread corresponding to the process.  This ptid
       is always alive until the program exits.  */
    return 1;

  /* Search whether an entry with the same tid exists in the dec-thread
     list of threads.  If it does, then the thread is still alive.
     No match found means that the thread must be dead, now.  */
  for (i = 0; VEC_iterate (dec_thread_info_s, dec_thread_list, i, info); i++)
    if (info->thread == tid)
      return 1;
  return 0;
}

/* Recompute the list of user threads and store the result in
   DEC_THREAD_LIST.  */

static void
update_dec_thread_list (void)
{
  pthreadDebugId_t thread;
  pthreadDebugThreadInfo_t info;
  int res;

  free_dec_thread_info_vec (&dec_thread_list);
  res = pthreadDebugThdSeqInit (debug_context, &thread);
  while (res == ESUCCESS)
    {

      res = pthreadDebugThdGetInfo (debug_context, thread, &info);
      if (res != ESUCCESS)
        warning (_("unable to get thread info, ignoring thread %ld"),
                   thread);
      else if (info.kind == PTHREAD_DEBUG_THD_KIND_INITIAL
               || info.kind == PTHREAD_DEBUG_THD_KIND_NORMAL)
        {
          struct dec_thread_info *item = 
            xmalloc (sizeof (struct dec_thread_info));

          item->thread = thread;
          item->info = info;
          VEC_safe_push (dec_thread_info_s, dec_thread_list, item);
        }
      res = pthreadDebugThdSeqNext (debug_context, &thread);
    }
  pthreadDebugThdSeqDestroy (debug_context);
}

/* Implement the update_thread_list target_ops method.  */

static void
dec_thread_update_thread_list (struct target_ops *ops)
{
  int i;
  struct dec_thread_info *info;
  struct thread_info *tp, *tmp;

  update_dec_thread_list ();

  /* Delete GDB-side threads no longer found in dec_thread_list.  */
  ALL_NON_EXITED_THREADS_SAFE (tp, tmp)
    {
      for (i = 0; VEC_iterate (dec_thread_info_s, dec_thread_list, i, info); i++)
	{
	  if (ptid_equal (info->ptid, tp->ptid))
	    break;
	}
      if (i == VEC_length (dec_thread_info_s, dec_thread_list))
	{
	  /* Not found.  */
	  delete_thread (tp->ptid);
	}
    }

  /* And now add new threads.  */
  for (i = 0; VEC_iterate (dec_thread_info_s, dec_thread_list, i, info); i++)
    {
      ptid_t ptid = ptid_build_from_info (*info);

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

/* The "to_detach" method of the dec_thread_ops.  */

static void
dec_thread_detach (struct target_ops *ops, const char *args, int from_tty)
{   
  struct target_ops *beneath = find_target_beneath (ops);

  debug ("dec_thread_detach");

  disable_dec_thread ();
  beneath->to_detach (beneath, args, from_tty);
}

/* Return the ptid of the thread that is currently active.  */

static ptid_t
get_active_ptid (void)
{
  int i;
  struct dec_thread_info *info;

  for (i = 0; VEC_iterate (dec_thread_info_s, dec_thread_list, i, info);
       i++)
    if (info->info.state == PTHREAD_DEBUG_STATE_RUNNING)
      return ptid_build_from_info (*info);

  /* No active thread found.  This can happen when the program
     has just exited.  */
  return null_ptid;
}

/* The "to_wait" method of the dec_thread_ops.  */

static ptid_t
dec_thread_wait (struct target_ops *ops,
		 ptid_t ptid, struct target_waitstatus *status, int options)
{
  ptid_t active_ptid;
  struct target_ops *beneath = find_target_beneath (ops);

  debug ("dec_thread_wait");

  ptid = beneath->to_wait (beneath, ptid, status, options);

  /* The ptid returned by the target beneath us is the ptid of the process.
     We need to find which thread is currently active and return its ptid.  */
  dec_thread_update_thread_list (ops);
  active_ptid = get_active_ptid ();
  if (ptid_equal (active_ptid, null_ptid))
    return ptid;
  return active_ptid;
}

/* Fetch the general purpose and floating point registers for the given
   thread TID, and store the result in GREGSET and FPREGSET.  Return
   zero if successful.  */

static int
dec_thread_get_regsets (pthreadDebugId_t tid, gdb_gregset_t *gregset,
                        gdb_fpregset_t *fpregset)
{
  int res;
  pthreadDebugRegs_t regs;
  pthreadDebugFregs_t fregs;

  res = pthreadDebugThdGetReg (debug_context, tid, &regs);
  if (res != ESUCCESS)
    {
      debug ("dec_thread_get_regsets: pthreadDebugThdGetReg -> %d", res);
      return -1;
    }
  memcpy (gregset->regs, &regs, sizeof (regs));

  res = pthreadDebugThdGetFreg (debug_context, tid, &fregs);
  if (res != ESUCCESS)
    {
      debug ("dec_thread_get_regsets: pthreadDebugThdGetFreg -> %d", res);
      return -1;
    }
  memcpy (fpregset->regs, &fregs, sizeof (fregs));

  return 0;
}

/* The "to_fetch_registers" method of the dec_thread_ops.

   Because the dec-thread debug API doesn't allow us to fetch
   only one register, we simply ignore regno and fetch+supply all
   registers.  */

static void
dec_thread_fetch_registers (struct target_ops *ops,
                            struct regcache *regcache, int regno)
{
  pthreadDebugId_t tid = ptid_get_tid (inferior_ptid);
  gregset_t gregset;
  fpregset_t fpregset;
  int res;

  debug ("dec_thread_fetch_registers (tid=%ld, regno=%d)", tid, regno);


  if (tid == 0 || ptid_equal (inferior_ptid, get_active_ptid ()))
    {
      struct target_ops *beneath = find_target_beneath (ops);

      beneath->to_fetch_registers (beneath, regcache, regno);
      return;
    }

  res = dec_thread_get_regsets (tid, &gregset, &fpregset);
  if (res != 0)
    return;

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

/* Store the registers given in GREGSET and FPREGSET into the associated
   general purpose and floating point registers of thread TID.  Return
   zero if successful.  */

static int
dec_thread_set_regsets (pthreadDebugId_t tid, gdb_gregset_t gregset,
                        gdb_fpregset_t fpregset)
{
  int res;
  pthreadDebugRegs_t regs;
  pthreadDebugFregs_t fregs;

  memcpy (&regs, gregset.regs, sizeof (regs));
  res = pthreadDebugThdSetReg (debug_context, tid, &regs);
  if (res != ESUCCESS)
    {
      debug ("dec_thread_set_regsets: pthreadDebugThdSetReg -> %d", res);
      return -1;
    }

  memcpy (&fregs, fpregset.regs, sizeof (fregs));
  res = pthreadDebugThdSetFreg (debug_context, tid, &fregs);
  if (res != ESUCCESS)
    {
      debug ("dec_thread_set_regsets: pthreadDebugThdSetFreg -> %d", res);
      return -1;
    }

  return 0;
}

/* The "to_store_registers" method of the dec_thread_ops.

   Because the dec-thread debug API doesn't allow us to store
   just one register, we store all the registers.  */

static void
dec_thread_store_registers (struct target_ops *ops,
                            struct regcache *regcache, int regno)
{
  pthreadDebugId_t tid = ptid_get_tid (inferior_ptid);
  gregset_t gregset;
  fpregset_t fpregset;
  int res;

  debug ("dec_thread_store_registers (tid=%ld, regno=%d)", tid, regno);

  if (tid == 0 || ptid_equal (inferior_ptid, get_active_ptid ()))
    {
      struct target_ops *beneath = find_target_beneath (ops);

      beneath->to_store_registers (beneath, regcache, regno);
      return;
    }

  /* FIXME: brobecker/2008-05-28: I wonder if we could simply check
     in which register set the register is and then only store the
     registers for that register set, instead of storing both register
     sets.  */
  fill_gregset (regcache, &gregset, -1);
  fill_fpregset (regcache, &fpregset, -1);
  
  res = dec_thread_set_regsets (tid, gregset, fpregset);
  if (res != 0)
    warning (_("failed to store registers."));
}

/* The "to_mourn_inferior" method of the dec_thread_ops.  */

static void
dec_thread_mourn_inferior (struct target_ops *ops)
{
  struct target_ops *beneath = find_target_beneath (ops);

  debug ("dec_thread_mourn_inferior");

  disable_dec_thread ();
  beneath->to_mourn_inferior (beneath);
}

/* The "to_thread_alive" method of the dec_thread_ops.  */
static int
dec_thread_thread_alive (struct target_ops *ops, ptid_t ptid)
{
  debug ("dec_thread_thread_alive (tid=%ld)", ptid_get_tid (ptid));

  /* The thread list maintained by GDB is up to date, since we update
     it everytime we stop.   So check this list.  */
  return in_thread_list (ptid);
}

/* The "to_pid_to_str" method of the dec_thread_ops.  */

static char *
dec_thread_pid_to_str (struct target_ops *ops, ptid_t ptid)
{
  static char *ret = NULL;

  if (ptid_get_tid (ptid) == 0)
    {
      struct target_ops *beneath = find_target_beneath (ops);

      return beneath->to_pid_to_str (beneath, ptid);
    }

  /* Free previous return value; a new one will be allocated by
     xstrprintf().  */
  xfree (ret);

  ret = xstrprintf (_("Thread %ld"), ptid_get_tid (ptid));
  return ret;
}

/* A "new-objfile" observer.  Used to activate/deactivate dec-thread
   support.  */

static void
dec_thread_new_objfile_observer (struct objfile *objfile)
{
  if (objfile != NULL)
     enable_dec_thread ();
  else
     disable_dec_thread ();
}

/* The "to_get_ada_task_ptid" method of the dec_thread_ops.  */

static ptid_t
dec_thread_get_ada_task_ptid (struct target_ops *self, long lwp, long thread)
{
  int i;
  struct dec_thread_info *info;

  debug ("dec_thread_get_ada_task_ptid (struct target_ops *self,"
	 " lwp=0x%lx, thread=0x%lx)",
         lwp, thread);

  for (i = 0; VEC_iterate (dec_thread_info_s, dec_thread_list, i, info);
       i++)
    if (info->info.teb == (pthread_t) thread)
      return ptid_build_from_info (*info);

  warning (_("Could not find thread id from THREAD = 0x%lx"), thread);
  return inferior_ptid;
}

static void
init_dec_thread_ops (void)
{
  dec_thread_ops.to_shortname          = "dec-threads";
  dec_thread_ops.to_longname           = _("DEC threads support");
  dec_thread_ops.to_doc                = _("DEC threads support");
  dec_thread_ops.to_detach             = dec_thread_detach;
  dec_thread_ops.to_wait               = dec_thread_wait;
  dec_thread_ops.to_fetch_registers    = dec_thread_fetch_registers;
  dec_thread_ops.to_store_registers    = dec_thread_store_registers;
  dec_thread_ops.to_mourn_inferior     = dec_thread_mourn_inferior;
  dec_thread_ops.to_thread_alive       = dec_thread_thread_alive;
  dec_thread_ops.to_update_thread_list = dec_thread_update_thread_list;
  dec_thread_ops.to_pid_to_str         = dec_thread_pid_to_str;
  dec_thread_ops.to_stratum            = thread_stratum;
  dec_thread_ops.to_get_ada_task_ptid  = dec_thread_get_ada_task_ptid;
  dec_thread_ops.to_magic              = OPS_MAGIC;
}

void
_initialize_dec_thread (void)
{
  init_dec_thread_ops ();
  complete_target_initialization (&dec_thread_ops);

  observer_attach_new_objfile (dec_thread_new_objfile_observer);

  add_setshow_boolean_cmd ("dec-thread", class_maintenance, &debug_dec_thread,
                            _("Set debugging of DEC threads module."),
                            _("Show debugging of DEC threads module."),
                            _("Enables debugging output (used to debug GDB)."),
                            NULL, NULL,
                            &setdebuglist, &showdebuglist);
}