* target.h (struct target_ops): Make to_has_all_memory,

[thirdparty/binutils-gdb.git] / gdb / windows-nat.c

/* Target-vector operations for controlling windows child processes, for GDB.

   Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
   2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.

   Contributed by Cygnus Solutions, A Red Hat Company.

   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/>.  */

/* Originally by Steve Chamberlain, sac@cygnus.com */

#include "defs.h"
#include "frame.h"              /* required by inferior.h */
#include "inferior.h"
#include "target.h"
#include "exceptions.h"
#include "gdbcore.h"
#include "command.h"
#include "completer.h"
#include "regcache.h"
#include "top.h"
#include <signal.h>
#include <sys/types.h>
#include <fcntl.h>
#include <stdlib.h>
#include <windows.h>
#include <imagehlp.h>
#include <psapi.h>
#ifdef __CYGWIN__
#include <sys/cygwin.h>
#endif
#include <signal.h>

#include "buildsym.h"
#include "symfile.h"
#include "objfiles.h"
#include "gdb_obstack.h"
#include "gdb_string.h"
#include "gdbthread.h"
#include "gdbcmd.h"
#include <sys/param.h>
#include <unistd.h>
#include "exec.h"
#include "solist.h"
#include "solib.h"
#include "xml-support.h"

#include "i386-tdep.h"
#include "i387-tdep.h"

#include "windows-tdep.h"
#include "windows-nat.h"
#include "i386-nat.h"

#define AdjustTokenPrivileges           dyn_AdjustTokenPrivileges
#define DebugActiveProcessStop          dyn_DebugActiveProcessStop
#define DebugBreakProcess               dyn_DebugBreakProcess
#define DebugSetProcessKillOnExit       dyn_DebugSetProcessKillOnExit
#define EnumProcessModules              dyn_EnumProcessModules
#define GetModuleFileNameExA            dyn_GetModuleFileNameExA
#define GetModuleInformation            dyn_GetModuleInformation
#define LookupPrivilegeValueA           dyn_LookupPrivilegeValueA
#define OpenProcessToken                dyn_OpenProcessToken

static BOOL WINAPI (*AdjustTokenPrivileges)(HANDLE, BOOL, PTOKEN_PRIVILEGES,
                                            DWORD, PTOKEN_PRIVILEGES, PDWORD);
static BOOL WINAPI (*DebugActiveProcessStop) (DWORD);
static BOOL WINAPI (*DebugBreakProcess) (HANDLE);
static BOOL WINAPI (*DebugSetProcessKillOnExit) (BOOL);
static BOOL WINAPI (*EnumProcessModules) (HANDLE, HMODULE *, DWORD,
                                          LPDWORD);
static DWORD WINAPI (*GetModuleFileNameExA) (HANDLE, HMODULE, LPSTR,
                                            DWORD);
static BOOL WINAPI (*GetModuleInformation) (HANDLE, HMODULE, LPMODULEINFO,
                                            DWORD);
static BOOL WINAPI (*LookupPrivilegeValueA)(LPCSTR, LPCSTR, PLUID);
static BOOL WINAPI (*OpenProcessToken)(HANDLE, DWORD, PHANDLE);

static struct target_ops windows_ops;

#ifdef __CYGWIN__
/* The starting and ending address of the cygwin1.dll text segment. */
static CORE_ADDR cygwin_load_start;
static CORE_ADDR cygwin_load_end;
#endif

static int have_saved_context;  /* True if we've saved context from a cygwin signal. */
static CONTEXT saved_context;   /* Containes the saved context from a cygwin signal. */

/* If we're not using the old Cygwin header file set, define the
   following which never should have been in the generic Win32 API
   headers in the first place since they were our own invention... */
#ifndef _GNU_H_WINDOWS_H
enum
  {
    FLAG_TRACE_BIT = 0x100,
    CONTEXT_DEBUGGER = (CONTEXT_FULL | CONTEXT_FLOATING_POINT)
  };
#endif

#ifndef CONTEXT_EXTENDED_REGISTERS
/* This macro is only defined on ia32.  It only makes sense on this target,
   so define it as zero if not already defined.  */
#define CONTEXT_EXTENDED_REGISTERS 0
#endif

#define CONTEXT_DEBUGGER_DR CONTEXT_DEBUGGER | CONTEXT_DEBUG_REGISTERS \
        | CONTEXT_EXTENDED_REGISTERS

static uintptr_t dr[8];
static int debug_registers_changed;
static int debug_registers_used;
#define DR6_CLEAR_VALUE 0xffff0ff0

/* The string sent by cygwin when it processes a signal.
   FIXME: This should be in a cygwin include file. */
#ifndef _CYGWIN_SIGNAL_STRING
#define _CYGWIN_SIGNAL_STRING "cYgSiGw00f"
#endif

#define CHECK(x)        check (x, __FILE__,__LINE__)
#define DEBUG_EXEC(x)   if (debug_exec)         printf_unfiltered x
#define DEBUG_EVENTS(x) if (debug_events)       printf_unfiltered x
#define DEBUG_MEM(x)    if (debug_memory)       printf_unfiltered x
#define DEBUG_EXCEPT(x) if (debug_exceptions)   printf_unfiltered x

static void windows_stop (ptid_t);
static int windows_thread_alive (struct target_ops *, ptid_t);
static void windows_kill_inferior (struct target_ops *);

static void cygwin_set_dr (int i, CORE_ADDR addr);
static void cygwin_set_dr7 (unsigned long val);
static unsigned long cygwin_get_dr6 (void);

static enum target_signal last_sig = TARGET_SIGNAL_0;
/* Set if a signal was received from the debugged process */

/* Thread information structure used to track information that is
   not available in gdb's thread structure.  */
typedef struct thread_info_struct
  {
    struct thread_info_struct *next;
    DWORD id;
    HANDLE h;
    char *name;
    int suspended;
    int reload_context;
    CONTEXT context;
    STACKFRAME sf;
  }
thread_info;

static thread_info thread_head;

/* The process and thread handles for the above context. */

static DEBUG_EVENT current_event;       /* The current debug event from
                                           WaitForDebugEvent */
static HANDLE current_process_handle;   /* Currently executing process */
static thread_info *current_thread;     /* Info on currently selected thread */
static DWORD main_thread_id;            /* Thread ID of the main thread */

/* Counts of things. */
static int exception_count = 0;
static int event_count = 0;
static int saw_create;
static int open_process_used = 0;

/* User options. */
static int new_console = 0;
#ifdef __CYGWIN__
static int cygwin_exceptions = 0;
#endif
static int new_group = 1;
static int debug_exec = 0;              /* show execution */
static int debug_events = 0;            /* show events from kernel */
static int debug_memory = 0;            /* show target memory accesses */
static int debug_exceptions = 0;        /* show target exceptions */
static int useshell = 0;                /* use shell for subprocesses */

/* This vector maps GDB's idea of a register's number into an offset
   in the windows exception context vector.

   It also contains the bit mask needed to load the register in question.

   The contents of this table can only be computed by the units
   that provide CPU-specific support for Windows native debugging.
   These units should set the table by calling
   windows_set_context_register_offsets.

   One day we could read a reg, we could inspect the context we
   already have loaded, if it doesn't have the bit set that we need,
   we read that set of registers in using GetThreadContext.  If the
   context already contains what we need, we just unpack it. Then to
   write a register, first we have to ensure that the context contains
   the other regs of the group, and then we copy the info in and set
   out bit. */

static const int *mappings;

/* This vector maps the target's idea of an exception (extracted
   from the DEBUG_EVENT structure) to GDB's idea. */

struct xlate_exception
  {
    int them;
    enum target_signal us;
  };

static const struct xlate_exception
  xlate[] =
{
  {EXCEPTION_ACCESS_VIOLATION, TARGET_SIGNAL_SEGV},
  {STATUS_STACK_OVERFLOW, TARGET_SIGNAL_SEGV},
  {EXCEPTION_BREAKPOINT, TARGET_SIGNAL_TRAP},
  {DBG_CONTROL_C, TARGET_SIGNAL_INT},
  {EXCEPTION_SINGLE_STEP, TARGET_SIGNAL_TRAP},
  {STATUS_FLOAT_DIVIDE_BY_ZERO, TARGET_SIGNAL_FPE},
  {-1, -1}};

/* Set the MAPPINGS static global to OFFSETS.
   See the description of MAPPINGS for more details.  */

void
windows_set_context_register_offsets (const int *offsets)
{
  mappings = offsets;
}

static void
check (BOOL ok, const char *file, int line)
{
  if (!ok)
    printf_filtered ("error return %s:%d was %lu\n", file, line,
                     GetLastError ());
}

/* Find a thread record given a thread id.  If GET_CONTEXT is not 0,
   then also retrieve the context for this thread.  If GET_CONTEXT is
   negative, then don't suspend the thread.  */
static thread_info *
thread_rec (DWORD id, int get_context)
{
  thread_info *th;

  for (th = &thread_head; (th = th->next) != NULL;)
    if (th->id == id)
      {
        if (!th->suspended && get_context)
          {
            if (get_context > 0 && id != current_event.dwThreadId)
              {
                if (SuspendThread (th->h) == (DWORD) -1)
                  {
                    DWORD err = GetLastError ();
                    warning (_("SuspendThread failed. (winerr %d)"),
                             (int) err);
                    return NULL;
                  }
                th->suspended = 1;
              }
            else if (get_context < 0)
              th->suspended = -1;
            th->reload_context = 1;
          }
        return th;
      }

  return NULL;
}

/* Add a thread to the thread list.  */
static thread_info *
windows_add_thread (ptid_t ptid, HANDLE h)
{
  thread_info *th;
  DWORD id;

  gdb_assert (ptid_get_tid (ptid) != 0);

  id = ptid_get_tid (ptid);

  if ((th = thread_rec (id, FALSE)))
    return th;

  th = XZALLOC (thread_info);
  th->id = id;
  th->h = h;
  th->next = thread_head.next;
  thread_head.next = th;
  add_thread (ptid);
  /* Set the debug registers for the new thread if they are used.  */
  if (debug_registers_used)
    {
      /* Only change the value of the debug registers.  */
      th->context.ContextFlags = CONTEXT_DEBUG_REGISTERS;
      CHECK (GetThreadContext (th->h, &th->context));
      th->context.Dr0 = dr[0];
      th->context.Dr1 = dr[1];
      th->context.Dr2 = dr[2];
      th->context.Dr3 = dr[3];
      th->context.Dr6 = DR6_CLEAR_VALUE;
      th->context.Dr7 = dr[7];
      CHECK (SetThreadContext (th->h, &th->context));
      th->context.ContextFlags = 0;
    }
  return th;
}

/* Clear out any old thread list and reintialize it to a
   pristine state. */
static void
windows_init_thread_list (void)
{
  thread_info *th = &thread_head;

  DEBUG_EVENTS (("gdb: windows_init_thread_list\n"));
  init_thread_list ();
  while (th->next != NULL)
    {
      thread_info *here = th->next;
      th->next = here->next;
      xfree (here);
    }
  thread_head.next = NULL;
}

/* Delete a thread from the list of threads */
static void
windows_delete_thread (ptid_t ptid)
{
  thread_info *th;
  DWORD id;

  gdb_assert (ptid_get_tid (ptid) != 0);

  id = ptid_get_tid (ptid);

  if (info_verbose)
    printf_unfiltered ("[Deleting %s]\n", target_pid_to_str (ptid));
  delete_thread (ptid);

  for (th = &thread_head;
       th->next != NULL && th->next->id != id;
       th = th->next)
    continue;

  if (th->next != NULL)
    {
      thread_info *here = th->next;
      th->next = here->next;
      xfree (here);
    }
}

static void
do_windows_fetch_inferior_registers (struct regcache *regcache, int r)
{
  char *context_offset = ((char *) &current_thread->context) + mappings[r];
  struct gdbarch *gdbarch = get_regcache_arch (regcache);
  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  long l;

  if (!current_thread)
    return;     /* Windows sometimes uses a non-existent thread id in its
                   events */

  if (current_thread->reload_context)
    {
#ifdef __COPY_CONTEXT_SIZE
      if (have_saved_context)
        {
          /* Lie about where the program actually is stopped since cygwin has informed us that
             we should consider the signal to have occurred at another location which is stored
             in "saved_context. */
          memcpy (&current_thread->context, &saved_context, __COPY_CONTEXT_SIZE);
          have_saved_context = 0;
        }
      else
#endif
        {
          thread_info *th = current_thread;
          th->context.ContextFlags = CONTEXT_DEBUGGER_DR;
          GetThreadContext (th->h, &th->context);
          /* Copy dr values from that thread.
             But only if there were not modified since last stop. PR gdb/2388 */
          if (!debug_registers_changed)
            {
              dr[0] = th->context.Dr0;
              dr[1] = th->context.Dr1;
              dr[2] = th->context.Dr2;
              dr[3] = th->context.Dr3;
              dr[6] = th->context.Dr6;
              dr[7] = th->context.Dr7;
            }
        }
      current_thread->reload_context = 0;
    }

  if (r == I387_FISEG_REGNUM (tdep))
    {
      l = *((long *) context_offset) & 0xffff;
      regcache_raw_supply (regcache, r, (char *) &l);
    }
  else if (r == I387_FOP_REGNUM (tdep))
    {
      l = (*((long *) context_offset) >> 16) & ((1 << 11) - 1);
      regcache_raw_supply (regcache, r, (char *) &l);
    }
  else if (r >= 0)
    regcache_raw_supply (regcache, r, context_offset);
  else
    {
      for (r = 0; r < gdbarch_num_regs (gdbarch); r++)
        do_windows_fetch_inferior_registers (regcache, r);
    }
}

static void
windows_fetch_inferior_registers (struct target_ops *ops,
                                  struct regcache *regcache, int r)
{
  current_thread = thread_rec (ptid_get_tid (inferior_ptid), TRUE);
  /* Check if current_thread exists.  Windows sometimes uses a non-existent
     thread id in its events */
  if (current_thread)
    do_windows_fetch_inferior_registers (regcache, r);
}

static void
do_windows_store_inferior_registers (const struct regcache *regcache, int r)
{
  if (!current_thread)
    /* Windows sometimes uses a non-existent thread id in its events */;
  else if (r >= 0)
    regcache_raw_collect (regcache, r,
                          ((char *) &current_thread->context) + mappings[r]);
  else
    {
      for (r = 0; r < gdbarch_num_regs (get_regcache_arch (regcache)); r++)
        do_windows_store_inferior_registers (regcache, r);
    }
}

/* Store a new register value into the current thread context */
static void
windows_store_inferior_registers (struct target_ops *ops,
                                  struct regcache *regcache, int r)
{
  current_thread = thread_rec (ptid_get_tid (inferior_ptid), TRUE);
  /* Check if current_thread exists.  Windows sometimes uses a non-existent
     thread id in its events */
  if (current_thread)
    do_windows_store_inferior_registers (regcache, r);
}

/* Get the name of a given module at at given base address.  If base_address
   is zero return the first loaded module (which is always the name of the
   executable).  */
static int
get_module_name (LPVOID base_address, char *dll_name_ret)
{
  DWORD len;
  MODULEINFO mi;
  int i;
  HMODULE dh_buf[1];
  HMODULE *DllHandle = dh_buf;  /* Set to temporary storage for initial query */
  DWORD cbNeeded;
#ifdef __CYGWIN__
  char pathbuf[PATH_MAX + 1];   /* Temporary storage prior to converting to
                                   posix form */
#else
  char *pathbuf = dll_name_ret; /* Just copy directly to passed-in arg */
#endif

  cbNeeded = 0;
  /* Find size of buffer needed to handle list of modules loaded in inferior */
  if (!EnumProcessModules (current_process_handle, DllHandle,
                           sizeof (HMODULE), &cbNeeded) || !cbNeeded)
    goto failed;

  /* Allocate correct amount of space for module list */
  DllHandle = (HMODULE *) alloca (cbNeeded);
  if (!DllHandle)
    goto failed;

  /* Get the list of modules */
  if (!EnumProcessModules (current_process_handle, DllHandle, cbNeeded,
                                 &cbNeeded))
    goto failed;

  for (i = 0; i < (int) (cbNeeded / sizeof (HMODULE)); i++)
    {
      /* Get information on this module */
      if (!GetModuleInformation (current_process_handle, DllHandle[i],
                                 &mi, sizeof (mi)))
        error (_("Can't get module info"));

      if (!base_address || mi.lpBaseOfDll == base_address)
        {
          /* Try to find the name of the given module */
          len = GetModuleFileNameExA (current_process_handle,
                                      DllHandle[i], pathbuf, MAX_PATH);
          if (len == 0)
            error (_("Error getting dll name: %u."), (unsigned) GetLastError ());
#ifdef __CYGWIN__
          /* Cygwin prefers that the path be in /x/y/z format */
          cygwin_conv_to_full_posix_path (pathbuf, dll_name_ret);
#endif
          return 1;     /* success */
        }
    }

failed:
  dll_name_ret[0] = '\0';
  return 0;             /* failure */
}

/* Encapsulate the information required in a call to
   symbol_file_add_args */
struct safe_symbol_file_add_args
{
  char *name;
  int from_tty;
  struct section_addr_info *addrs;
  int mainline;
  int flags;
  struct ui_file *err, *out;
  struct objfile *ret;
};

/* Maintain a linked list of "so" information. */
struct lm_info
{
  LPVOID load_addr;
};

static struct so_list solib_start, *solib_end;

/* Call symbol_file_add with stderr redirected.  We don't care if there
   are errors. */
static int
safe_symbol_file_add_stub (void *argv)
{
#define p ((struct safe_symbol_file_add_args *) argv)
  p->ret = symbol_file_add (p->name, p->from_tty, p->addrs, p->mainline, p->flags);
  return !!p->ret;
#undef p
}

/* Restore gdb's stderr after calling symbol_file_add */
static void
safe_symbol_file_add_cleanup (void *p)
{
#define sp ((struct safe_symbol_file_add_args *)p)
  gdb_flush (gdb_stderr);
  gdb_flush (gdb_stdout);
  ui_file_delete (gdb_stderr);
  ui_file_delete (gdb_stdout);
  gdb_stderr = sp->err;
  gdb_stdout = sp->out;
#undef sp
}

/* symbol_file_add wrapper that prevents errors from being displayed. */
static struct objfile *
safe_symbol_file_add (char *name, int from_tty,
                      struct section_addr_info *addrs,
                      int mainline, int flags)
{
  struct safe_symbol_file_add_args p;
  struct cleanup *cleanup;

  cleanup = make_cleanup (safe_symbol_file_add_cleanup, &p);

  p.err = gdb_stderr;
  p.out = gdb_stdout;
  gdb_flush (gdb_stderr);
  gdb_flush (gdb_stdout);
  gdb_stderr = ui_file_new ();
  gdb_stdout = ui_file_new ();
  p.name = name;
  p.from_tty = from_tty;
  p.addrs = addrs;
  p.mainline = mainline;
  p.flags = flags;
  catch_errors (safe_symbol_file_add_stub, &p, "", RETURN_MASK_ERROR);

  do_cleanups (cleanup);
  return p.ret;
}

static struct so_list *
windows_make_so (const char *name, LPVOID load_addr)
{
  struct so_list *so;
  char buf[MAX_PATH + 1];
  char cwd[MAX_PATH + 1];
  char *p;
  WIN32_FIND_DATA w32_fd;
  HANDLE h = FindFirstFile(name, &w32_fd);
  MEMORY_BASIC_INFORMATION m;

  if (h == INVALID_HANDLE_VALUE)
    strcpy (buf, name);
  else
    {
      FindClose (h);
      strcpy (buf, name);
      if (GetCurrentDirectory (MAX_PATH + 1, cwd))
        {
          p = strrchr (buf, '\\');
          if (p)
            p[1] = '\0';
          SetCurrentDirectory (buf);
          GetFullPathName (w32_fd.cFileName, MAX_PATH, buf, &p);
          SetCurrentDirectory (cwd);
        }
    }

  if (strcasecmp (buf, "ntdll.dll") == 0)
    {
      GetSystemDirectory (buf, sizeof (buf));
      strcat (buf, "\\ntdll.dll");
    }
  so = XZALLOC (struct so_list);
  so->lm_info = (struct lm_info *) xmalloc (sizeof (struct lm_info));
  so->lm_info->load_addr = load_addr;
  strcpy (so->so_original_name, name);
#ifndef __CYGWIN__
  strcpy (so->so_name, buf);
#else
  cygwin_conv_to_posix_path (buf, so->so_name);
  /* Record cygwin1.dll .text start/end.  */
  p = strchr (so->so_name, '\0') - (sizeof ("/cygwin1.dll") - 1);
  if (p >= so->so_name && strcasecmp (p, "/cygwin1.dll") == 0)
    {
      bfd *abfd;
      asection *text = NULL;
      CORE_ADDR text_vma;

      abfd = bfd_openr (so->so_name, "pei-i386");

      if (!abfd)
        return so;

      if (bfd_check_format (abfd, bfd_object))
        text = bfd_get_section_by_name (abfd, ".text");

      if (!text)
        {
          bfd_close (abfd);
          return so;
        }

      /* The symbols in a dll are offset by 0x1000, which is the the
         offset from 0 of the first byte in an image - because of the
         file header and the section alignment. */
      cygwin_load_start = (CORE_ADDR) (uintptr_t) ((char *) load_addr + 0x1000);
      cygwin_load_end = cygwin_load_start + bfd_section_size (abfd, text);

      bfd_close (abfd);
    }
#endif

  return so;
}

static char *
get_image_name (HANDLE h, void *address, int unicode)
{
  static char buf[(2 * MAX_PATH) + 1];
  DWORD size = unicode ? sizeof (WCHAR) : sizeof (char);
  char *address_ptr;
  int len = 0;
  char b[2];
  SIZE_T done;

  /* Attempt to read the name of the dll that was detected.
     This is documented to work only when actively debugging
     a program.  It will not work for attached processes. */
  if (address == NULL)
    return NULL;

  /* See if we could read the address of a string, and that the
     address isn't null. */
  if (!ReadProcessMemory (h, address,  &address_ptr, sizeof (address_ptr), &done)
      || done != sizeof (address_ptr) || !address_ptr)
    return NULL;

  /* Find the length of the string */
  while (ReadProcessMemory (h, address_ptr + len++ * size, &b, size, &done)
         && (b[0] != 0 || b[size - 1] != 0) && done == size)
    continue;

  if (!unicode)
    ReadProcessMemory (h, address_ptr, buf, len, &done);
  else
    {
      WCHAR *unicode_address = (WCHAR *) alloca (len * sizeof (WCHAR));
      ReadProcessMemory (h, address_ptr, unicode_address, len * sizeof (WCHAR),
                         &done);

      WideCharToMultiByte (CP_ACP, 0, unicode_address, len, buf, len, 0, 0);
    }

  return buf;
}

/* Wait for child to do something.  Return pid of child, or -1 in case
   of error; store status through argument pointer OURSTATUS.  */
static int
handle_load_dll (void *dummy)
{
  LOAD_DLL_DEBUG_INFO *event = &current_event.u.LoadDll;
  char dll_buf[MAX_PATH + 1];
  char *dll_name = NULL;

  dll_buf[0] = dll_buf[sizeof (dll_buf) - 1] = '\0';

  if (!get_module_name (event->lpBaseOfDll, dll_buf))
    dll_buf[0] = dll_buf[sizeof (dll_buf) - 1] = '\0';

  dll_name = dll_buf;

  if (*dll_name == '\0')
    dll_name = get_image_name (current_process_handle,
                               event->lpImageName, event->fUnicode);
  if (!dll_name)
    return 1;

  solib_end->next = windows_make_so (dll_name, event->lpBaseOfDll);
  solib_end = solib_end->next;

  DEBUG_EVENTS (("gdb: Loading dll \"%s\" at %s.\n", solib_end->so_name,
                 host_address_to_string (solib_end->lm_info->load_addr)));

  return 1;
}

static void
windows_free_so (struct so_list *so)
{
  if (so->lm_info)
    xfree (so->lm_info);
  xfree (so);
}

static int
handle_unload_dll (void *dummy)
{
  LPVOID lpBaseOfDll = current_event.u.UnloadDll.lpBaseOfDll;
  struct so_list *so;

  for (so = &solib_start; so->next != NULL; so = so->next)
    if (so->next->lm_info->load_addr == lpBaseOfDll)
      {
        struct so_list *sodel = so->next;
        so->next = sodel->next;
        if (!so->next)
          solib_end = so;
        DEBUG_EVENTS (("gdb: Unloading dll \"%s\".\n", sodel->so_name));

        windows_free_so (sodel);
        solib_add (NULL, 0, NULL, auto_solib_add);
        return 1;
      }

  error (_("Error: dll starting at %s not found."),
           host_address_to_string (lpBaseOfDll));

  return 0;
}

/* Clear list of loaded DLLs. */
static void
windows_clear_solib (void)
{
  solib_start.next = NULL;
  solib_end = &solib_start;
}

/* Load DLL symbol info. */
void
dll_symbol_command (char *args, int from_tty)
{
  int n;
  dont_repeat ();

  if (args == NULL)
    error (_("dll-symbols requires a file name"));

  n = strlen (args);
  if (n > 4 && strcasecmp (args + n - 4, ".dll") != 0)
    {
      char *newargs = (char *) alloca (n + 4 + 1);
      strcpy (newargs, args);
      strcat (newargs, ".dll");
      args = newargs;
    }

  safe_symbol_file_add (args, from_tty, NULL, 0, OBJF_SHARED | OBJF_USERLOADED);
}

/* Handle DEBUG_STRING output from child process.
   Cygwin prepends its messages with a "cygwin:".  Interpret this as
   a Cygwin signal.  Otherwise just print the string as a warning. */
static int
handle_output_debug_string (struct target_waitstatus *ourstatus)
{
  char *s = NULL;
  int retval = 0;

  if (!target_read_string
        ((CORE_ADDR) (uintptr_t) current_event.u.DebugString.lpDebugStringData,
        &s, 1024, 0)
      || !s || !*s)
    /* nothing to do */;
  else if (strncmp (s, _CYGWIN_SIGNAL_STRING, sizeof (_CYGWIN_SIGNAL_STRING) - 1) != 0)
    {
#ifdef __CYGWIN__
      if (strncmp (s, "cYg", 3) != 0)
#endif
        warning (("%s"), s);
    }
#ifdef __COPY_CONTEXT_SIZE
  else
    {
      /* Got a cygwin signal marker.  A cygwin signal is followed by the signal number
         itself and then optionally followed by the thread id and address to saved context
         within the DLL.  If these are supplied, then the given thread is assumed to have
         issued the signal and the context from the thread is assumed to be stored at the
         given address in the inferior.  Tell gdb to treat this like a real signal.  */
      char *p;
      int sig = strtol (s + sizeof (_CYGWIN_SIGNAL_STRING) - 1, &p, 0);
      int gotasig = target_signal_from_host (sig);
      ourstatus->value.sig = gotasig;
      if (gotasig)
        {
          LPCVOID x;
          DWORD n;
          ourstatus->kind = TARGET_WAITKIND_STOPPED;
          retval = strtoul (p, &p, 0);
          if (!retval)
            retval = main_thread_id;
          else if ((x = (LPCVOID) strtoul (p, &p, 0))
                   && ReadProcessMemory (current_process_handle, x,
                                         &saved_context, __COPY_CONTEXT_SIZE, &n)
                   && n == __COPY_CONTEXT_SIZE)
            have_saved_context = 1;
          current_event.dwThreadId = retval;
        }
    }
#endif

  if (s)
    xfree (s);
  return retval;
}

static int
display_selector (HANDLE thread, DWORD sel)
{
  LDT_ENTRY info;
  if (GetThreadSelectorEntry (thread, sel, &info))
    {
      int base, limit;
      printf_filtered ("0x%03lx: ", sel);
      if (!info.HighWord.Bits.Pres)
        {
          puts_filtered ("Segment not present\n");
          return 0;
        }
      base = (info.HighWord.Bits.BaseHi << 24) +
             (info.HighWord.Bits.BaseMid << 16)
             + info.BaseLow;
      limit = (info.HighWord.Bits.LimitHi << 16) + info.LimitLow;
      if (info.HighWord.Bits.Granularity)
        limit = (limit << 12) | 0xfff;
      printf_filtered ("base=0x%08x limit=0x%08x", base, limit);
      if (info.HighWord.Bits.Default_Big)
        puts_filtered(" 32-bit ");
      else
        puts_filtered(" 16-bit ");
      switch ((info.HighWord.Bits.Type & 0xf) >> 1)
        {
        case 0:
          puts_filtered ("Data (Read-Only, Exp-up");
          break;
        case 1:
          puts_filtered ("Data (Read/Write, Exp-up");
          break;
        case 2:
          puts_filtered ("Unused segment (");
          break;
        case 3:
          puts_filtered ("Data (Read/Write, Exp-down");
          break;
        case 4:
          puts_filtered ("Code (Exec-Only, N.Conf");
          break;
        case 5:
          puts_filtered ("Code (Exec/Read, N.Conf");
          break;
        case 6:
          puts_filtered ("Code (Exec-Only, Conf");
          break;
        case 7:
          puts_filtered ("Code (Exec/Read, Conf");
          break;
        default:
          printf_filtered ("Unknown type 0x%x",info.HighWord.Bits.Type);
        }
      if ((info.HighWord.Bits.Type & 0x1) == 0)
        puts_filtered(", N.Acc");
      puts_filtered (")\n");
      if ((info.HighWord.Bits.Type & 0x10) == 0)
        puts_filtered("System selector ");
      printf_filtered ("Priviledge level = %d. ", info.HighWord.Bits.Dpl);
      if (info.HighWord.Bits.Granularity)
        puts_filtered ("Page granular.\n");
      else
        puts_filtered ("Byte granular.\n");
      return 1;
    }
  else
    {
      printf_filtered ("Invalid selector 0x%lx.\n",sel);
      return 0;
    }
}

static void
display_selectors (char * args, int from_tty)
{
  if (!current_thread)
    {
      puts_filtered ("Impossible to display selectors now.\n");
      return;
    }
  if (!args)
    {

      puts_filtered ("Selector $cs\n");
      display_selector (current_thread->h,
        current_thread->context.SegCs);
      puts_filtered ("Selector $ds\n");
      display_selector (current_thread->h,
        current_thread->context.SegDs);
      puts_filtered ("Selector $es\n");
      display_selector (current_thread->h,
        current_thread->context.SegEs);
      puts_filtered ("Selector $ss\n");
      display_selector (current_thread->h,
        current_thread->context.SegSs);
      puts_filtered ("Selector $fs\n");
      display_selector (current_thread->h,
        current_thread->context.SegFs);
      puts_filtered ("Selector $gs\n");
      display_selector (current_thread->h,
        current_thread->context.SegGs);
    }
  else
    {
      int sel;
      sel = parse_and_eval_long (args);
      printf_filtered ("Selector \"%s\"\n",args);
      display_selector (current_thread->h, sel);
    }
}

static struct cmd_list_element *info_w32_cmdlist = NULL;

static void
info_w32_command (char *args, int from_tty)
{
  help_list (info_w32_cmdlist, "info w32 ", class_info, gdb_stdout);
}


#define DEBUG_EXCEPTION_SIMPLE(x)       if (debug_exceptions) \
  printf_unfiltered ("gdb: Target exception %s at %s\n", x, \
    host_address_to_string (\
      current_event.u.Exception.ExceptionRecord.ExceptionAddress))

static int
handle_exception (struct target_waitstatus *ourstatus)
{
  thread_info *th;
  DWORD code = current_event.u.Exception.ExceptionRecord.ExceptionCode;

  ourstatus->kind = TARGET_WAITKIND_STOPPED;

  /* Record the context of the current thread */
  th = thread_rec (current_event.dwThreadId, -1);

  switch (code)
    {
    case EXCEPTION_ACCESS_VIOLATION:
      DEBUG_EXCEPTION_SIMPLE ("EXCEPTION_ACCESS_VIOLATION");
      ourstatus->value.sig = TARGET_SIGNAL_SEGV;
#ifdef __CYGWIN__
      {
        /* See if the access violation happened within the cygwin DLL itself.  Cygwin uses
           a kind of exception handling to deal with passed-in invalid addresses. gdb
           should not treat these as real SEGVs since they will be silently handled by
           cygwin.  A real SEGV will (theoretically) be caught by cygwin later in the process
           and will be sent as a cygwin-specific-signal.  So, ignore SEGVs if they show up
           within the text segment of the DLL itself. */
        char *fn;
        CORE_ADDR addr = (CORE_ADDR) (uintptr_t) current_event.u.Exception.ExceptionRecord.ExceptionAddress;
        if ((!cygwin_exceptions && (addr >= cygwin_load_start && addr < cygwin_load_end))
            || (find_pc_partial_function (addr, &fn, NULL, NULL)
                && strncmp (fn, "KERNEL32!IsBad", strlen ("KERNEL32!IsBad")) == 0))
          return 0;
      }
#endif
      break;
    case STATUS_STACK_OVERFLOW:
      DEBUG_EXCEPTION_SIMPLE ("STATUS_STACK_OVERFLOW");
      ourstatus->value.sig = TARGET_SIGNAL_SEGV;
      break;
    case STATUS_FLOAT_DENORMAL_OPERAND:
      DEBUG_EXCEPTION_SIMPLE ("STATUS_FLOAT_DENORMAL_OPERAND");
      ourstatus->value.sig = TARGET_SIGNAL_FPE;
      break;
    case EXCEPTION_ARRAY_BOUNDS_EXCEEDED:
      DEBUG_EXCEPTION_SIMPLE ("EXCEPTION_ARRAY_BOUNDS_EXCEEDED");
      ourstatus->value.sig = TARGET_SIGNAL_FPE;
      break;
    case STATUS_FLOAT_INEXACT_RESULT:
      DEBUG_EXCEPTION_SIMPLE ("STATUS_FLOAT_INEXACT_RESULT");
      ourstatus->value.sig = TARGET_SIGNAL_FPE;
      break;
    case STATUS_FLOAT_INVALID_OPERATION:
      DEBUG_EXCEPTION_SIMPLE ("STATUS_FLOAT_INVALID_OPERATION");
      ourstatus->value.sig = TARGET_SIGNAL_FPE;
      break;
    case STATUS_FLOAT_OVERFLOW:
      DEBUG_EXCEPTION_SIMPLE ("STATUS_FLOAT_OVERFLOW");
      ourstatus->value.sig = TARGET_SIGNAL_FPE;
      break;
    case STATUS_FLOAT_STACK_CHECK:
      DEBUG_EXCEPTION_SIMPLE ("STATUS_FLOAT_STACK_CHECK");
      ourstatus->value.sig = TARGET_SIGNAL_FPE;
      break;
    case STATUS_FLOAT_UNDERFLOW:
      DEBUG_EXCEPTION_SIMPLE ("STATUS_FLOAT_UNDERFLOW");
      ourstatus->value.sig = TARGET_SIGNAL_FPE;
      break;
    case STATUS_FLOAT_DIVIDE_BY_ZERO:
      DEBUG_EXCEPTION_SIMPLE ("STATUS_FLOAT_DIVIDE_BY_ZERO");
      ourstatus->value.sig = TARGET_SIGNAL_FPE;
      break;
    case STATUS_INTEGER_DIVIDE_BY_ZERO:
      DEBUG_EXCEPTION_SIMPLE ("STATUS_INTEGER_DIVIDE_BY_ZERO");
      ourstatus->value.sig = TARGET_SIGNAL_FPE;
      break;
    case STATUS_INTEGER_OVERFLOW:
      DEBUG_EXCEPTION_SIMPLE ("STATUS_INTEGER_OVERFLOW");
      ourstatus->value.sig = TARGET_SIGNAL_FPE;
      break;
    case EXCEPTION_BREAKPOINT:
      DEBUG_EXCEPTION_SIMPLE ("EXCEPTION_BREAKPOINT");
      ourstatus->value.sig = TARGET_SIGNAL_TRAP;
      break;
    case DBG_CONTROL_C:
      DEBUG_EXCEPTION_SIMPLE ("DBG_CONTROL_C");
      ourstatus->value.sig = TARGET_SIGNAL_INT;
      break;
    case DBG_CONTROL_BREAK:
      DEBUG_EXCEPTION_SIMPLE ("DBG_CONTROL_BREAK");
      ourstatus->value.sig = TARGET_SIGNAL_INT;
      break;
    case EXCEPTION_SINGLE_STEP:
      DEBUG_EXCEPTION_SIMPLE ("EXCEPTION_SINGLE_STEP");
      ourstatus->value.sig = TARGET_SIGNAL_TRAP;
      break;
    case EXCEPTION_ILLEGAL_INSTRUCTION:
      DEBUG_EXCEPTION_SIMPLE ("EXCEPTION_ILLEGAL_INSTRUCTION");
      ourstatus->value.sig = TARGET_SIGNAL_ILL;
      break;
    case EXCEPTION_PRIV_INSTRUCTION:
      DEBUG_EXCEPTION_SIMPLE ("EXCEPTION_PRIV_INSTRUCTION");
      ourstatus->value.sig = TARGET_SIGNAL_ILL;
      break;
    case EXCEPTION_NONCONTINUABLE_EXCEPTION:
      DEBUG_EXCEPTION_SIMPLE ("EXCEPTION_NONCONTINUABLE_EXCEPTION");
      ourstatus->value.sig = TARGET_SIGNAL_ILL;
      break;
    default:
      /* Treat unhandled first chance exceptions specially. */
      if (current_event.u.Exception.dwFirstChance)
        return -1;
      printf_unfiltered ("gdb: unknown target exception 0x%08lx at %s\n",
        current_event.u.Exception.ExceptionRecord.ExceptionCode,
        host_address_to_string (
          current_event.u.Exception.ExceptionRecord.ExceptionAddress));
      ourstatus->value.sig = TARGET_SIGNAL_UNKNOWN;
      break;
    }
  exception_count++;
  last_sig = ourstatus->value.sig;
  return 1;
}

/* Resume all artificially suspended threads if we are continuing
   execution */
static BOOL
windows_continue (DWORD continue_status, int id)
{
  int i;
  thread_info *th;
  BOOL res;

  DEBUG_EVENTS (("ContinueDebugEvent (cpid=%ld, ctid=%ld, %s);\n",
                  current_event.dwProcessId, current_event.dwThreadId,
                  continue_status == DBG_CONTINUE ?
                  "DBG_CONTINUE" : "DBG_EXCEPTION_NOT_HANDLED"));

  for (th = &thread_head; (th = th->next) != NULL;)
    if ((id == -1 || id == (int) th->id)
        && th->suspended)
      {
        if (debug_registers_changed)
          {
            th->context.ContextFlags |= CONTEXT_DEBUG_REGISTERS;
            th->context.Dr0 = dr[0];
            th->context.Dr1 = dr[1];
            th->context.Dr2 = dr[2];
            th->context.Dr3 = dr[3];
            th->context.Dr6 = DR6_CLEAR_VALUE;
            th->context.Dr7 = dr[7];
          }
        if (th->context.ContextFlags)
          {
            CHECK (SetThreadContext (th->h, &th->context));
            th->context.ContextFlags = 0;
          }
        if (th->suspended > 0)
          (void) ResumeThread (th->h);
        th->suspended = 0;
      }

  res = ContinueDebugEvent (current_event.dwProcessId,
                            current_event.dwThreadId,
                            continue_status);

  debug_registers_changed = 0;
  return res;
}

/* Called in pathological case where Windows fails to send a
   CREATE_PROCESS_DEBUG_EVENT after an attach.  */
static DWORD
fake_create_process (void)
{
  current_process_handle = OpenProcess (PROCESS_ALL_ACCESS, FALSE,
                                        current_event.dwProcessId);
  if (current_process_handle != NULL)
    open_process_used = 1;
  else
    {
      error (_("OpenProcess call failed, GetLastError = %lud\n"),
       GetLastError ());
      /*  We can not debug anything in that case.  */
    }
  main_thread_id = current_event.dwThreadId;
  current_thread = windows_add_thread (ptid_build (current_event.dwProcessId, 0,
                                                   current_event.dwThreadId),
                                       current_event.u.CreateThread.hThread);
  return main_thread_id;
}

static void
windows_resume (struct target_ops *ops,
                ptid_t ptid, int step, enum target_signal sig)
{
  thread_info *th;
  DWORD continue_status = DBG_CONTINUE;

  /* A specific PTID means `step only this thread id'.  */
  int resume_all = ptid_equal (ptid, minus_one_ptid);

  /* If we're continuing all threads, it's the current inferior that
     should be handled specially.  */
  if (resume_all)
    ptid = inferior_ptid;

  if (sig != TARGET_SIGNAL_0)
    {
      if (current_event.dwDebugEventCode != EXCEPTION_DEBUG_EVENT)
        {
          DEBUG_EXCEPT(("Cannot continue with signal %d here.\n",sig));
        }
      else if (sig == last_sig)
        continue_status = DBG_EXCEPTION_NOT_HANDLED;
      else
#if 0
/* This code does not seem to work, because
  the kernel does probably not consider changes in the ExceptionRecord
  structure when passing the exception to the inferior.
  Note that this seems possible in the exception handler itself.  */
        {
          int i;
          for (i = 0; xlate[i].them != -1; i++)
            if (xlate[i].us == sig)
              {
                current_event.u.Exception.ExceptionRecord.ExceptionCode =
                  xlate[i].them;
                continue_status = DBG_EXCEPTION_NOT_HANDLED;
                break;
              }
          if (continue_status == DBG_CONTINUE)
            {
              DEBUG_EXCEPT(("Cannot continue with signal %d.\n",sig));
            }
        }
#endif
        DEBUG_EXCEPT(("Can only continue with recieved signal %d.\n",
          last_sig));
    }

  last_sig = TARGET_SIGNAL_0;

  DEBUG_EXEC (("gdb: windows_resume (pid=%d, tid=%ld, step=%d, sig=%d);\n",
               ptid_get_pid (ptid), ptid_get_tid (ptid), step, sig));

  /* Get context for currently selected thread */
  th = thread_rec (ptid_get_tid (inferior_ptid), FALSE);
  if (th)
    {
      if (step)
        {
          /* Single step by setting t bit */
          windows_fetch_inferior_registers (ops,
                                            get_current_regcache (),
                                            gdbarch_ps_regnum (current_gdbarch));
          th->context.EFlags |= FLAG_TRACE_BIT;
        }

      if (th->context.ContextFlags)
        {
          if (debug_registers_changed)
            {
              th->context.Dr0 = dr[0];
              th->context.Dr1 = dr[1];
              th->context.Dr2 = dr[2];
              th->context.Dr3 = dr[3];
              th->context.Dr6 = DR6_CLEAR_VALUE;
              th->context.Dr7 = dr[7];
            }
          CHECK (SetThreadContext (th->h, &th->context));
          th->context.ContextFlags = 0;
        }
    }

  /* Allow continuing with the same signal that interrupted us.
     Otherwise complain. */

  if (resume_all)
    windows_continue (continue_status, -1);
  else
    windows_continue (continue_status, ptid_get_tid (ptid));
}

/* Ctrl-C handler used when the inferior is not run in the same console.  The
   handler is in charge of interrupting the inferior using DebugBreakProcess.
   Note that this function is not available prior to Windows XP.  In this case
   we emit a warning.  */
BOOL WINAPI
ctrl_c_handler (DWORD event_type)
{
  const int attach_flag = current_inferior ()->attach_flag;

  /* Only handle Ctrl-C event.  Ignore others.  */
  if (event_type != CTRL_C_EVENT)
    return FALSE;

  /* If the inferior and the debugger share the same console, do nothing as
     the inferior has also received the Ctrl-C event.  */
  if (!new_console && !attach_flag)
    return TRUE;

  if (!DebugBreakProcess (current_process_handle))
    warning (_("\
Could not interrupt program.  Press Ctrl-c in the program console."));

  /* Return true to tell that Ctrl-C has been handled.  */
  return TRUE;
}

/* Get the next event from the child.  Return 1 if the event requires
   handling by WFI (or whatever).  */
static int
get_windows_debug_event (struct target_ops *ops,
                         int pid, struct target_waitstatus *ourstatus)
{
  BOOL debug_event;
  DWORD continue_status, event_code;
  thread_info *th;
  static thread_info dummy_thread_info;
  int retval = 0;

  last_sig = TARGET_SIGNAL_0;

  if (!(debug_event = WaitForDebugEvent (&current_event, 1000)))
    goto out;

  event_count++;
  continue_status = DBG_CONTINUE;

  event_code = current_event.dwDebugEventCode;
  ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
  th = NULL;
  have_saved_context = 0;

  switch (event_code)
    {
    case CREATE_THREAD_DEBUG_EVENT:
      DEBUG_EVENTS (("gdb: kernel event for pid=%d tid=%x code=%s)\n",
                     (unsigned) current_event.dwProcessId,
                     (unsigned) current_event.dwThreadId,
                     "CREATE_THREAD_DEBUG_EVENT"));
      if (saw_create != 1)
        {
          struct inferior *inf;
          inf = find_inferior_pid (current_event.dwProcessId);
          if (!saw_create && inf->attach_flag)
            {
              /* Kludge around a Windows bug where first event is a create
                 thread event.  Caused when attached process does not have
                 a main thread. */
              retval = fake_create_process ();
              if (retval)
                saw_create++;
            }
          break;
        }
      /* Record the existence of this thread */
      retval = current_event.dwThreadId;
      th = windows_add_thread (ptid_build (current_event.dwProcessId, 0,
                                         current_event.dwThreadId),
                             current_event.u.CreateThread.hThread);
      break;

    case EXIT_THREAD_DEBUG_EVENT:
      DEBUG_EVENTS (("gdb: kernel event for pid=%d tid=%d code=%s)\n",
                     (unsigned) current_event.dwProcessId,
                     (unsigned) current_event.dwThreadId,
                     "EXIT_THREAD_DEBUG_EVENT"));
      if (current_event.dwThreadId != main_thread_id)
        {
          windows_delete_thread (ptid_build (current_event.dwProcessId, 0,
                                           current_event.dwThreadId));
          th = &dummy_thread_info;
        }
      break;

    case CREATE_PROCESS_DEBUG_EVENT:
      DEBUG_EVENTS (("gdb: kernel event for pid=%d tid=%d code=%s)\n",
                     (unsigned) current_event.dwProcessId,
                     (unsigned) current_event.dwThreadId,
                     "CREATE_PROCESS_DEBUG_EVENT"));
      CloseHandle (current_event.u.CreateProcessInfo.hFile);
      if (++saw_create != 1)
        break;

      current_process_handle = current_event.u.CreateProcessInfo.hProcess;
      if (main_thread_id)
        windows_delete_thread (ptid_build (current_event.dwProcessId, 0,
                                           main_thread_id));
      main_thread_id = current_event.dwThreadId;
      /* Add the main thread */
      th = windows_add_thread (ptid_build (current_event.dwProcessId, 0,
                                           current_event.dwThreadId),
                               current_event.u.CreateProcessInfo.hThread);
      retval = current_event.dwThreadId;
      break;

    case EXIT_PROCESS_DEBUG_EVENT:
      DEBUG_EVENTS (("gdb: kernel event for pid=%d tid=%d code=%s)\n",
                     (unsigned) current_event.dwProcessId,
                     (unsigned) current_event.dwThreadId,
                     "EXIT_PROCESS_DEBUG_EVENT"));
      if (saw_create != 1)
        break;
      ourstatus->kind = TARGET_WAITKIND_EXITED;
      ourstatus->value.integer = current_event.u.ExitProcess.dwExitCode;
      retval = main_thread_id;
      break;

    case LOAD_DLL_DEBUG_EVENT:
      DEBUG_EVENTS (("gdb: kernel event for pid=%d tid=%d code=%s)\n",
                     (unsigned) current_event.dwProcessId,
                     (unsigned) current_event.dwThreadId,
                     "LOAD_DLL_DEBUG_EVENT"));
      CloseHandle (current_event.u.LoadDll.hFile);
      if (saw_create != 1)
        break;
      catch_errors (handle_load_dll, NULL, (char *) "", RETURN_MASK_ALL);
      ourstatus->kind = TARGET_WAITKIND_LOADED;
      ourstatus->value.integer = 0;
      retval = main_thread_id;
      break;

    case UNLOAD_DLL_DEBUG_EVENT:
      DEBUG_EVENTS (("gdb: kernel event for pid=%d tid=%d code=%s)\n",
                     (unsigned) current_event.dwProcessId,
                     (unsigned) current_event.dwThreadId,
                     "UNLOAD_DLL_DEBUG_EVENT"));
      if (saw_create != 1)
        break;
      catch_errors (handle_unload_dll, NULL, (char *) "", RETURN_MASK_ALL);
      ourstatus->kind = TARGET_WAITKIND_LOADED;
      ourstatus->value.integer = 0;
      retval = main_thread_id;
      break;

    case EXCEPTION_DEBUG_EVENT:
      DEBUG_EVENTS (("gdb: kernel event for pid=%d tid=%d code=%s)\n",
                     (unsigned) current_event.dwProcessId,
                     (unsigned) current_event.dwThreadId,
                     "EXCEPTION_DEBUG_EVENT"));
      if (saw_create != 1)
        break;
      switch (handle_exception (ourstatus))
        {
        case 0:
          continue_status = DBG_EXCEPTION_NOT_HANDLED;
          break;
        case 1:
          retval = current_event.dwThreadId;
          break;
        case -1:
          last_sig = 1;
          continue_status = -1;
          break;
        }
      break;

    case OUTPUT_DEBUG_STRING_EVENT:     /* message from the kernel */
      DEBUG_EVENTS (("gdb: kernel event for pid=%d tid=%d code=%s)\n",
                     (unsigned) current_event.dwProcessId,
                     (unsigned) current_event.dwThreadId,
                     "OUTPUT_DEBUG_STRING_EVENT"));
      if (saw_create != 1)
        break;
      retval = handle_output_debug_string (ourstatus);
      break;

    default:
      if (saw_create != 1)
        break;
      printf_unfiltered ("gdb: kernel event for pid=%ld tid=%ld\n",
                         (DWORD) current_event.dwProcessId,
                         (DWORD) current_event.dwThreadId);
      printf_unfiltered ("                 unknown event code %ld\n",
                         current_event.dwDebugEventCode);
      break;
    }

  if (!retval || saw_create != 1)
    {
      if (continue_status == -1)
        windows_resume (ops, minus_one_ptid, 0, 1);
      else
        CHECK (windows_continue (continue_status, -1));
    }
  else
    {
      inferior_ptid = ptid_build (current_event.dwProcessId, 0,
                                  retval);
      current_thread = th ?: thread_rec (current_event.dwThreadId, TRUE);
    }

out:
  return retval;
}

/* Wait for interesting events to occur in the target process.  */
static ptid_t
windows_wait (struct target_ops *ops,
              ptid_t ptid, struct target_waitstatus *ourstatus, int options)
{
  int pid = -1;

  target_terminal_ours ();

  /* We loop when we get a non-standard exception rather than return
     with a SPURIOUS because resume can try and step or modify things,
     which needs a current_thread->h.  But some of these exceptions mark
     the birth or death of threads, which mean that the current thread
     isn't necessarily what you think it is. */

  while (1)
    {
      int retval;

      /* If the user presses Ctrl-c while the debugger is waiting
         for an event, he expects the debugger to interrupt his program
         and to get the prompt back.  There are two possible situations:

           - The debugger and the program do not share the console, in
             which case the Ctrl-c event only reached the debugger.
             In that case, the ctrl_c handler will take care of interrupting
             the inferior. Note that this case is working starting with
             Windows XP. For Windows 2000, Ctrl-C should be pressed in the
             inferior console.

           - The debugger and the program share the same console, in which
             case both debugger and inferior will receive the Ctrl-c event.
             In that case the ctrl_c handler will ignore the event, as the
             Ctrl-c event generated inside the inferior will trigger the
             expected debug event.

             FIXME: brobecker/2008-05-20: If the inferior receives the
             signal first and the delay until GDB receives that signal
             is sufficiently long, GDB can sometimes receive the SIGINT
             after we have unblocked the CTRL+C handler.  This would
             lead to the debugger stopping prematurely while handling
             the new-thread event that comes with the handling of the SIGINT
             inside the inferior, and then stop again immediately when
             the user tries to resume the execution in the inferior.
             This is a classic race that we should try to fix one day.  */
      SetConsoleCtrlHandler (&ctrl_c_handler, TRUE);
      retval = get_windows_debug_event (ops, pid, ourstatus);
      SetConsoleCtrlHandler (&ctrl_c_handler, FALSE);

      if (retval)
        return ptid_build (current_event.dwProcessId, 0, retval);
      else
        {
          int detach = 0;

          if (deprecated_ui_loop_hook != NULL)
            detach = deprecated_ui_loop_hook (0);

          if (detach)
            windows_kill_inferior (ops);
        }
    }
}

static void
do_initial_windows_stuff (struct target_ops *ops, DWORD pid, int attaching)
{
  extern int stop_after_trap;
  int i;
  struct inferior *inf;
  struct thread_info *tp;

  last_sig = TARGET_SIGNAL_0;
  event_count = 0;
  exception_count = 0;
  open_process_used = 0;
  debug_registers_changed = 0;
  debug_registers_used = 0;
  for (i = 0; i < sizeof (dr) / sizeof (dr[0]); i++)
    dr[i] = 0;
#ifdef __CYGWIN__
  cygwin_load_start = cygwin_load_end = 0;
#endif
  current_event.dwProcessId = pid;
  memset (&current_event, 0, sizeof (current_event));
  push_target (ops);
  disable_breakpoints_in_shlibs ();
  windows_clear_solib ();
  clear_proceed_status ();
  init_wait_for_inferior ();

  inf = add_inferior (pid);
  inf->attach_flag = attaching;

  /* Make the new process the current inferior, so terminal handling
     can rely on it.  When attaching, we don't know about any thread
     id here, but that's OK --- nothing should be referencing the
     current thread until we report an event out of windows_wait.  */
  inferior_ptid = pid_to_ptid (pid);

  terminal_init_inferior_with_pgrp (pid);
  target_terminal_inferior ();

  inf->stop_soon = STOP_QUIETLY;
  while (1)
    {
      stop_after_trap = 1;
      wait_for_inferior (0);
      tp = inferior_thread ();
      if (tp->stop_signal != TARGET_SIGNAL_TRAP)
        resume (0, tp->stop_signal);
      else
        break;
    }

  inf->stop_soon = NO_STOP_QUIETLY;
  stop_after_trap = 0;
  return;
}

/* Try to set or remove a user privilege to the current process.  Return -1
   if that fails, the previous setting of that privilege otherwise.

   This code is copied from the Cygwin source code and rearranged to allow
   dynamically loading of the needed symbols from advapi32 which is only
   available on NT/2K/XP. */
static int
set_process_privilege (const char *privilege, BOOL enable)
{
  HANDLE token_hdl = NULL;
  LUID restore_priv;
  TOKEN_PRIVILEGES new_priv, orig_priv;
  int ret = -1;
  DWORD size;

  if (!OpenProcessToken (GetCurrentProcess (),
                         TOKEN_QUERY | TOKEN_ADJUST_PRIVILEGES,
                         &token_hdl))
    goto out;

  if (!LookupPrivilegeValueA (NULL, privilege, &restore_priv))
    goto out;

  new_priv.PrivilegeCount = 1;
  new_priv.Privileges[0].Luid = restore_priv;
  new_priv.Privileges[0].Attributes = enable ? SE_PRIVILEGE_ENABLED : 0;

  if (!AdjustTokenPrivileges (token_hdl, FALSE, &new_priv,
                              sizeof orig_priv, &orig_priv, &size))
    goto out;
#if 0
  /* Disabled, otherwise every `attach' in an unprivileged user session
     would raise the "Failed to get SE_DEBUG_NAME privilege" warning in
     windows_attach(). */
  /* AdjustTokenPrivileges returns TRUE even if the privilege could not
     be enabled. GetLastError () returns an correct error code, though. */
  if (enable && GetLastError () == ERROR_NOT_ALL_ASSIGNED)
    goto out;
#endif

  ret = orig_priv.Privileges[0].Attributes == SE_PRIVILEGE_ENABLED ? 1 : 0;

out:
  if (token_hdl)
    CloseHandle (token_hdl);

  return ret;
}

/* Attach to process PID, then initialize for debugging it.  */
static void
windows_attach (struct target_ops *ops, char *args, int from_tty)
{
  BOOL ok;
  DWORD pid;

  if (!args)
    error_no_arg (_("process-id to attach"));

  if (set_process_privilege (SE_DEBUG_NAME, TRUE) < 0)
    {
      printf_unfiltered ("Warning: Failed to get SE_DEBUG_NAME privilege\n");
      printf_unfiltered ("This can cause attach to fail on Windows NT/2K/XP\n");
    }

  pid = strtoul (args, 0, 0);           /* Windows pid */

  windows_init_thread_list ();
  ok = DebugActiveProcess (pid);
  saw_create = 0;

#ifdef __CYGWIN__
  if (!ok)
    {
      /* Try fall back to Cygwin pid */
      pid = cygwin_internal (CW_CYGWIN_PID_TO_WINPID, pid);

      if (pid > 0)
        ok = DebugActiveProcess (pid);
  }
#endif

  if (!ok)
    error (_("Can't attach to process."));

  DebugSetProcessKillOnExit (FALSE);

  if (from_tty)
    {
      char *exec_file = (char *) get_exec_file (0);

      if (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",
                           target_pid_to_str (pid_to_ptid (pid)));

      gdb_flush (gdb_stdout);
    }

  do_initial_windows_stuff (ops, pid, 1);
  target_terminal_ours ();
}

static void
windows_detach (struct target_ops *ops, char *args, int from_tty)
{
  int detached = 1;

  ptid_t ptid = {-1};
  windows_resume (ops, ptid, 0, TARGET_SIGNAL_0);

  if (!DebugActiveProcessStop (current_event.dwProcessId))
    {
      error (_("Can't detach process %lu (error %lu)"),
             current_event.dwProcessId, GetLastError ());
      detached = 0;
    }
  DebugSetProcessKillOnExit (FALSE);

  if (detached && from_tty)
    {
      char *exec_file = get_exec_file (0);
      if (exec_file == 0)
        exec_file = "";
      printf_unfiltered ("Detaching from program: %s, Pid %lu\n", exec_file,
                         current_event.dwProcessId);
      gdb_flush (gdb_stdout);
    }

  inferior_ptid = null_ptid;
  detach_inferior (current_event.dwProcessId);

  unpush_target (ops);
}

static char *
windows_pid_to_exec_file (int pid)
{
  static char path[MAX_PATH + 1];

#ifdef __CYGWIN__
  /* Try to find exe name as symlink target of /proc/<pid>/exe */
  int nchars;
  char procexe[sizeof ("/proc/4294967295/exe")];
  sprintf (procexe, "/proc/%u/exe", pid);
  nchars = readlink (procexe, path, sizeof(path));
  if (nchars > 0 && nchars < sizeof (path))
    {
      path[nchars] = '\0';      /* Got it */
      return path;
    }
#endif

  /* If we get here then either Cygwin is hosed, this isn't a Cygwin version
     of gdb, or we're trying to debug a non-Cygwin windows executable. */
  if (!get_module_name (0, path))
    path[0] = '\0';

  return path;
}

/* Print status information about what we're accessing.  */

static void
windows_files_info (struct target_ops *ignore)
{
  struct inferior *inf = current_inferior ();

  printf_unfiltered ("\tUsing the running image of %s %s.\n",
                     inf->attach_flag ? "attached" : "child",
                     target_pid_to_str (inferior_ptid));
}

static void
windows_open (char *arg, int from_tty)
{
  error (_("Use the \"run\" command to start a Unix child process."));
}

/* Start an inferior windows 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().  */

static void
windows_create_inferior (struct target_ops *ops, char *exec_file,
                       char *allargs, char **in_env, int from_tty)
{
  STARTUPINFO si;
  PROCESS_INFORMATION pi;
  BOOL ret;
  DWORD flags;
  char *args;
  char real_path[MAXPATHLEN];
  char *toexec;
  char shell[MAX_PATH + 1]; /* Path to shell */
  const char *sh;
#ifdef __CYGWIN__
  int tty;
  int ostdin, ostdout, ostderr;
#else
  HANDLE tty;
#endif
  const char *inferior_io_terminal = get_inferior_io_terminal ();

  if (!exec_file)
    error (_("No executable specified, use `target exec'."));

  memset (&si, 0, sizeof (si));
  si.cb = sizeof (si);

#ifdef __CYGWIN__
  if (!useshell)
    {
      flags = DEBUG_ONLY_THIS_PROCESS;
      cygwin_conv_to_win32_path (exec_file, real_path);
      toexec = real_path;
    }
  else
    {
      char *newallargs;
      sh = getenv ("SHELL");
      if (!sh)
        sh = "/bin/sh";
      cygwin_conv_to_win32_path (sh, shell);
      newallargs = alloca (sizeof (" -c 'exec  '") + strlen (exec_file)
                           + strlen (allargs) + 2);
      sprintf (newallargs, " -c 'exec %s %s'", exec_file, allargs);
      allargs = newallargs;
      toexec = shell;
      flags = DEBUG_PROCESS;
    }
#else
  toexec = exec_file;
  flags = DEBUG_ONLY_THIS_PROCESS;
#endif

  if (new_group)
    flags |= CREATE_NEW_PROCESS_GROUP;

  if (new_console)
    flags |= CREATE_NEW_CONSOLE;

  args = alloca (strlen (toexec) + strlen (allargs) + 2);
  strcpy (args, toexec);
  strcat (args, " ");
  strcat (args, allargs);

#ifdef __CYGWIN__
  /* Prepare the environment vars for CreateProcess.  */
  cygwin_internal (CW_SYNC_WINENV);

  if (!inferior_io_terminal)
    tty = ostdin = ostdout = ostderr = -1;
  else
    {
      tty = open (inferior_io_terminal, O_RDWR | O_NOCTTY);
      if (tty < 0)
        {
          print_sys_errmsg (inferior_io_terminal, errno);
          ostdin = ostdout = ostderr = -1;
        }
      else
        {
          ostdin = dup (0);
          ostdout = dup (1);
          ostderr = dup (2);
          dup2 (tty, 0);
          dup2 (tty, 1);
          dup2 (tty, 2);
        }
    }
#else
  if (!inferior_io_terminal)
    tty = INVALID_HANDLE_VALUE;
  else
    {
      SECURITY_ATTRIBUTES sa;
      sa.nLength = sizeof(sa);
      sa.lpSecurityDescriptor = 0;
      sa.bInheritHandle = TRUE;
      tty = CreateFileA (inferior_io_terminal, GENERIC_READ | GENERIC_WRITE,
                         0, &sa, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);
      if (tty == INVALID_HANDLE_VALUE)
        warning (_("Warning: Failed to open TTY %s, error %#x."),
                 inferior_io_terminal, (unsigned) GetLastError ());
      else
        {
          si.hStdInput = tty;
          si.hStdOutput = tty;
          si.hStdError = tty;
          si.dwFlags |= STARTF_USESTDHANDLES;
        }
    }
#endif

  windows_init_thread_list ();
  ret = CreateProcess (0,
                       args,    /* command line */
                       NULL,    /* Security */
                       NULL,    /* thread */
                       TRUE,    /* inherit handles */
                       flags,   /* start flags */
                       NULL,    /* environment */
                       NULL,    /* current directory */
                       &si,
                       &pi);

#ifdef __CYGWIN__
  if (tty >= 0)
    {
      close (tty);
      dup2 (ostdin, 0);
      dup2 (ostdout, 1);
      dup2 (ostderr, 2);
      close (ostdin);
      close (ostdout);
      close (ostderr);
    }
#else
  if (tty != INVALID_HANDLE_VALUE)
    CloseHandle (tty);
#endif

  if (!ret)
    error (_("Error creating process %s, (error %d)."),
           exec_file, (unsigned) GetLastError ());

  CloseHandle (pi.hThread);
  CloseHandle (pi.hProcess);

  if (useshell && shell[0] != '\0')
    saw_create = -1;
  else
    saw_create = 0;

  do_initial_windows_stuff (ops, pi.dwProcessId, 0);

  /* windows_continue (DBG_CONTINUE, -1); */
}

static void
windows_mourn_inferior (struct target_ops *ops)
{
  (void) windows_continue (DBG_CONTINUE, -1);
  i386_cleanup_dregs();
  if (open_process_used)
    {
      CHECK (CloseHandle (current_process_handle));
      open_process_used = 0;
    }
  unpush_target (ops);
  generic_mourn_inferior ();
}

/* Send a SIGINT to the process group.  This acts just like the user typed a
   ^C on the controlling terminal. */

static void
windows_stop (ptid_t ptid)
{
  DEBUG_EVENTS (("gdb: GenerateConsoleCtrlEvent (CTRLC_EVENT, 0)\n"));
  CHECK (GenerateConsoleCtrlEvent (CTRL_C_EVENT, current_event.dwProcessId));
  registers_changed ();         /* refresh register state */
}

static int
windows_xfer_memory (CORE_ADDR memaddr, gdb_byte *our, int len,
                   int write, struct mem_attrib *mem,
                   struct target_ops *target)
{
  SIZE_T done = 0;
  if (write)
    {
      DEBUG_MEM (("gdb: write target memory, %d bytes at 0x%08lx\n",
                  len, (DWORD) (uintptr_t) memaddr));
      if (!WriteProcessMemory (current_process_handle,
                               (LPVOID) (uintptr_t) memaddr, our,
                               len, &done))
        done = 0;
      FlushInstructionCache (current_process_handle,
                             (LPCVOID) (uintptr_t) memaddr, len);
    }
  else
    {
      DEBUG_MEM (("gdb: read target memory, %d bytes at 0x%08lx\n",
                  len, (DWORD) (uintptr_t) memaddr));
      if (!ReadProcessMemory (current_process_handle,
                              (LPCVOID) (uintptr_t) memaddr, our,
                              len, &done))
        done = 0;
    }
  return done;
}

static void
windows_kill_inferior (struct target_ops *ops)
{
  CHECK (TerminateProcess (current_process_handle, 0));

  for (;;)
    {
      if (!windows_continue (DBG_CONTINUE, -1))
        break;
      if (!WaitForDebugEvent (&current_event, INFINITE))
        break;
      if (current_event.dwDebugEventCode == EXIT_PROCESS_DEBUG_EVENT)
        break;
    }

  target_mourn_inferior ();     /* or just windows_mourn_inferior? */
}

static void
windows_prepare_to_store (struct regcache *regcache)
{
  /* Do nothing, since we can store individual regs */
}

static int
windows_can_run (void)
{
  return 1;
}

static void
windows_close (int x)
{
  DEBUG_EVENTS (("gdb: windows_close, inferior_ptid=%d\n",
                PIDGET (inferior_ptid)));
}

/* Convert pid to printable format. */
static char *
windows_pid_to_str (struct target_ops *ops, ptid_t ptid)
{
  static char buf[80];

  if (ptid_get_tid (ptid) != 0)
    {
      snprintf (buf, sizeof (buf), "Thread %d.0x%lx",
                ptid_get_pid (ptid), ptid_get_tid (ptid));
      return buf;
    }

  return normal_pid_to_str (ptid);
}

static LONGEST
windows_xfer_shared_libraries (struct target_ops *ops,
                             enum target_object object, const char *annex,
                             gdb_byte *readbuf, const gdb_byte *writebuf,
                             ULONGEST offset, LONGEST len)
{
  struct obstack obstack;
  const char *buf;
  LONGEST len_avail;
  struct so_list *so;

  if (writebuf)
    return -1;

  obstack_init (&obstack);
  obstack_grow_str (&obstack, "<library-list>\n");
  for (so = solib_start.next; so; so = so->next)
    windows_xfer_shared_library (so->so_name, (CORE_ADDR) (uintptr_t) so->lm_info->load_addr,
                                 &obstack);
  obstack_grow_str0 (&obstack, "</library-list>\n");

  buf = obstack_finish (&obstack);
  len_avail = strlen (buf);
  if (offset >= len_avail)
    return 0;

  if (len > len_avail - offset)
    len = len_avail - offset;
  memcpy (readbuf, buf + offset, len);

  obstack_free (&obstack, NULL);
  return len;
}

static LONGEST
windows_xfer_partial (struct target_ops *ops, enum target_object object,
                    const char *annex, gdb_byte *readbuf,
                    const gdb_byte *writebuf, ULONGEST offset, LONGEST len)
{
  switch (object)
    {
    case TARGET_OBJECT_MEMORY:
      if (readbuf)
        return (*ops->deprecated_xfer_memory) (offset, readbuf,
                                               len, 0/*read*/, NULL, ops);
      if (writebuf)
        return (*ops->deprecated_xfer_memory) (offset, (gdb_byte *) writebuf,
                                               len, 1/*write*/, NULL, ops);
      return -1;

    case TARGET_OBJECT_LIBRARIES:
      return windows_xfer_shared_libraries (ops, object, annex, readbuf,
                                          writebuf, offset, len);

    default:
      if (ops->beneath != NULL)
        return ops->beneath->to_xfer_partial (ops->beneath, object, annex,
                                              readbuf, writebuf, offset, len);
      return -1;
    }
}

static ptid_t
windows_get_ada_task_ptid (long lwp, long thread)
{
  return ptid_build (ptid_get_pid (inferior_ptid), 0, lwp);
}

static void
init_windows_ops (void)
{
  windows_ops.to_shortname = "child";
  windows_ops.to_longname = "Win32 child process";
  windows_ops.to_doc = "Win32 child process (started by the \"run\" command).";
  windows_ops.to_open = windows_open;
  windows_ops.to_close = windows_close;
  windows_ops.to_attach = windows_attach;
  windows_ops.to_attach_no_wait = 1;
  windows_ops.to_detach = windows_detach;
  windows_ops.to_resume = windows_resume;
  windows_ops.to_wait = windows_wait;
  windows_ops.to_fetch_registers = windows_fetch_inferior_registers;
  windows_ops.to_store_registers = windows_store_inferior_registers;
  windows_ops.to_prepare_to_store = windows_prepare_to_store;
  windows_ops.deprecated_xfer_memory = windows_xfer_memory;
  windows_ops.to_xfer_partial = windows_xfer_partial;
  windows_ops.to_files_info = windows_files_info;
  windows_ops.to_insert_breakpoint = memory_insert_breakpoint;
  windows_ops.to_remove_breakpoint = memory_remove_breakpoint;
  windows_ops.to_terminal_init = terminal_init_inferior;
  windows_ops.to_terminal_inferior = terminal_inferior;
  windows_ops.to_terminal_ours_for_output = terminal_ours_for_output;
  windows_ops.to_terminal_ours = terminal_ours;
  windows_ops.to_terminal_save_ours = terminal_save_ours;
  windows_ops.to_terminal_info = child_terminal_info;
  windows_ops.to_kill = windows_kill_inferior;
  windows_ops.to_create_inferior = windows_create_inferior;
  windows_ops.to_mourn_inferior = windows_mourn_inferior;
  windows_ops.to_can_run = windows_can_run;
  windows_ops.to_thread_alive = windows_thread_alive;
  windows_ops.to_pid_to_str = windows_pid_to_str;
  windows_ops.to_stop = windows_stop;
  windows_ops.to_stratum = process_stratum;
  windows_ops.to_has_all_memory = default_child_has_all_memory;
  windows_ops.to_has_memory = default_child_has_memory;
  windows_ops.to_has_stack = default_child_has_stack;
  windows_ops.to_has_registers = default_child_has_registers;
  windows_ops.to_has_execution = default_child_has_execution;
  windows_ops.to_pid_to_exec_file = windows_pid_to_exec_file;
  windows_ops.to_get_ada_task_ptid = windows_get_ada_task_ptid;

  i386_use_watchpoints (&windows_ops);

  i386_dr_low.set_control = cygwin_set_dr7;
  i386_dr_low.set_addr = cygwin_set_dr;
  i386_dr_low.reset_addr = NULL;
  i386_dr_low.get_status = cygwin_get_dr6;

  /* i386_dr_low.debug_register_length field is set by
     calling i386_set_debug_register_length function
     in processor windows specific native file.  */

  windows_ops.to_magic = OPS_MAGIC;
}

static void
set_windows_aliases (char *argv0)
{
  add_info_alias ("dll", "sharedlibrary", 1);
}

void
_initialize_windows_nat (void)
{
  struct cmd_list_element *c;

  init_windows_ops ();

  c = add_com ("dll-symbols", class_files, dll_symbol_command,
               _("Load dll library symbols from FILE."));
  set_cmd_completer (c, filename_completer);

  add_com_alias ("sharedlibrary", "dll-symbols", class_alias, 1);

  add_com_alias ("add-shared-symbol-files", "dll-symbols", class_alias, 1);

  add_com_alias ("assf", "dll-symbols", class_alias, 1);

#ifdef __CYGWIN__
  add_setshow_boolean_cmd ("shell", class_support, &useshell, _("\
Set use of shell to start subprocess."), _("\
Show use of shell to start subprocess."), NULL,
                           NULL,
                           NULL, /* FIXME: i18n: */
                           &setlist, &showlist);

  add_setshow_boolean_cmd ("cygwin-exceptions", class_support, &cygwin_exceptions, _("\
Break when an exception is detected in the Cygwin DLL itself."), _("\
Show whether gdb breaks on exceptions in the Cygwin DLL itself."), NULL,
                           NULL,
                           NULL, /* FIXME: i18n: */
                           &setlist, &showlist);
#endif

  add_setshow_boolean_cmd ("new-console", class_support, &new_console, _("\
Set creation of new console when creating child process."), _("\
Show creation of new console when creating child process."), NULL,
                           NULL,
                           NULL, /* FIXME: i18n: */
                           &setlist, &showlist);

  add_setshow_boolean_cmd ("new-group", class_support, &new_group, _("\
Set creation of new group when creating child process."), _("\
Show creation of new group when creating child process."), NULL,
                           NULL,
                           NULL, /* FIXME: i18n: */
                           &setlist, &showlist);

  add_setshow_boolean_cmd ("debugexec", class_support, &debug_exec, _("\
Set whether to display execution in child process."), _("\
Show whether to display execution in child process."), NULL,
                           NULL,
                           NULL, /* FIXME: i18n: */
                           &setlist, &showlist);

  add_setshow_boolean_cmd ("debugevents", class_support, &debug_events, _("\
Set whether to display kernel events in child process."), _("\
Show whether to display kernel events in child process."), NULL,
                           NULL,
                           NULL, /* FIXME: i18n: */
                           &setlist, &showlist);

  add_setshow_boolean_cmd ("debugmemory", class_support, &debug_memory, _("\
Set whether to display memory accesses in child process."), _("\
Show whether to display memory accesses in child process."), NULL,
                           NULL,
                           NULL, /* FIXME: i18n: */
                           &setlist, &showlist);

  add_setshow_boolean_cmd ("debugexceptions", class_support,
                           &debug_exceptions, _("\
Set whether to display kernel exceptions in child process."), _("\
Show whether to display kernel exceptions in child process."), NULL,
                           NULL,
                           NULL, /* FIXME: i18n: */
                           &setlist, &showlist);

  add_prefix_cmd ("w32", class_info, info_w32_command,
                  _("Print information specific to Win32 debugging."),
                  &info_w32_cmdlist, "info w32 ", 0, &infolist);

  add_cmd ("selector", class_info, display_selectors,
           _("Display selectors infos."),
           &info_w32_cmdlist);
  add_target (&windows_ops);
  deprecated_init_ui_hook = set_windows_aliases;
}

/* Hardware watchpoint support, adapted from go32-nat.c code.  */

/* Pass the address ADDR to the inferior in the I'th debug register.
   Here we just store the address in dr array, the registers will be
   actually set up when windows_continue is called.  */
static void
cygwin_set_dr (int i, CORE_ADDR addr)
{
  if (i < 0 || i > 3)
    internal_error (__FILE__, __LINE__,
                    _("Invalid register %d in cygwin_set_dr.\n"), i);
  dr[i] = addr;
  debug_registers_changed = 1;
  debug_registers_used = 1;
}

/* Pass the value VAL to the inferior in the DR7 debug control
   register.  Here we just store the address in D_REGS, the watchpoint
   will be actually set up in windows_wait.  */
static void
cygwin_set_dr7 (unsigned long val)
{
  dr[7] = (CORE_ADDR) val;
  debug_registers_changed = 1;
  debug_registers_used = 1;
}

/* Get the value of the DR6 debug status register from the inferior.
   Here we just return the value stored in dr[6]
   by the last call to thread_rec for current_event.dwThreadId id.  */
static unsigned long
cygwin_get_dr6 (void)
{
  return (unsigned long) dr[6];
}

/* Determine if the thread referenced by "ptid" is alive
   by "polling" it.  If WaitForSingleObject returns WAIT_OBJECT_0
   it means that the thread has died.  Otherwise it is assumed to be alive. */
static int
windows_thread_alive (struct target_ops *ops, ptid_t ptid)
{
  int tid;

  gdb_assert (ptid_get_tid (ptid) != 0);
  tid = ptid_get_tid (ptid);

  return WaitForSingleObject (thread_rec (tid, FALSE)->h, 0) == WAIT_OBJECT_0 ?
    FALSE : TRUE;
}

void
_initialize_check_for_gdb_ini (void)
{
  char *homedir;
  if (inhibit_gdbinit)
    return;

  homedir = getenv ("HOME");
  if (homedir)
    {
      char *p;
      char *oldini = (char *) alloca (strlen (homedir) +
                                      sizeof ("/gdb.ini"));
      strcpy (oldini, homedir);
      p = strchr (oldini, '\0');
      if (p > oldini && p[-1] != '/')
        *p++ = '/';
      strcpy (p, "gdb.ini");
      if (access (oldini, 0) == 0)
        {
          int len = strlen (oldini);
          char *newini = alloca (len + 1);
          sprintf (newini, "%.*s.gdbinit",
            (int) (len - (sizeof ("gdb.ini") - 1)), oldini);
          warning (_("obsolete '%s' found. Rename to '%s'."), oldini, newini);
        }
    }
}

/* Define dummy functions which always return error for the rare cases where
   these functions could not be found. */
static BOOL WINAPI
bad_DebugActiveProcessStop (DWORD w)
{
  return FALSE;
}
static BOOL WINAPI
bad_DebugBreakProcess (HANDLE w)
{
  return FALSE;
}
static BOOL WINAPI
bad_DebugSetProcessKillOnExit (BOOL w)
{
  return FALSE;
}
static BOOL WINAPI
bad_EnumProcessModules (HANDLE w, HMODULE *x, DWORD y, LPDWORD z)
{
  return FALSE;
}
static DWORD WINAPI
bad_GetModuleFileNameExA (HANDLE w, HMODULE x, LPSTR y, DWORD z)
{
  return 0;
}
static BOOL WINAPI
bad_GetModuleInformation (HANDLE w, HMODULE x, LPMODULEINFO y, DWORD z)
{
  return FALSE;
}

static BOOL WINAPI
bad_OpenProcessToken (HANDLE w, DWORD x, PHANDLE y)
{
  return FALSE;
}

/* Load any functions which may not be available in ancient versions
   of Windows. */
void
_initialize_loadable (void)
{
  HMODULE hm = NULL;

  hm = LoadLibrary ("kernel32.dll");
  if (hm)
    {
      dyn_DebugActiveProcessStop = (void *)
        GetProcAddress (hm, "DebugActiveProcessStop");
      dyn_DebugBreakProcess = (void *)
        GetProcAddress (hm, "DebugBreakProcess");
      dyn_DebugSetProcessKillOnExit = (void *)
        GetProcAddress (hm, "DebugSetProcessKillOnExit");
    }

  /* Set variables to dummy versions of these processes if the function
     wasn't found in kernel32.dll. */
  if (!dyn_DebugBreakProcess)
    dyn_DebugBreakProcess = bad_DebugBreakProcess;
  if (!dyn_DebugActiveProcessStop || !dyn_DebugSetProcessKillOnExit)
    {
      dyn_DebugActiveProcessStop = bad_DebugActiveProcessStop;
      dyn_DebugSetProcessKillOnExit = bad_DebugSetProcessKillOnExit;
    }

  /* Load optional functions used for retrieving filename information
     associated with the currently debugged process or its dlls. */
  hm = LoadLibrary ("psapi.dll");
  if (hm)
    {
      dyn_EnumProcessModules = (void *)
        GetProcAddress (hm, "EnumProcessModules");
      dyn_GetModuleInformation = (void *)
        GetProcAddress (hm, "GetModuleInformation");
      dyn_GetModuleFileNameExA = (void *)
        GetProcAddress (hm, "GetModuleFileNameExA");
    }

  if (!dyn_EnumProcessModules || !dyn_GetModuleInformation || !dyn_GetModuleFileNameExA)
    {
      /* Set variables to dummy versions of these processes if the function
         wasn't found in psapi.dll. */
      dyn_EnumProcessModules = bad_EnumProcessModules;
      dyn_GetModuleInformation = bad_GetModuleInformation;
      dyn_GetModuleFileNameExA = bad_GetModuleFileNameExA;
      /* This will probably fail on Windows 9x/Me.  Let the user know that we're
         missing some functionality. */
      warning(_("cannot automatically find executable file or library to read symbols.\nUse \"file\" or \"dll\" command to load executable/libraries directly."));
    }

  hm = LoadLibrary ("advapi32.dll");
  if (hm)
    {
      dyn_OpenProcessToken = (void *)
        GetProcAddress (hm, "OpenProcessToken");
      dyn_LookupPrivilegeValueA = (void *)
        GetProcAddress (hm, "LookupPrivilegeValueA");
      dyn_AdjustTokenPrivileges = (void *)
        GetProcAddress (hm, "AdjustTokenPrivileges");
      /* Only need to set one of these since if OpenProcessToken fails nothing
         else is needed. */
      if (!dyn_OpenProcessToken || !dyn_LookupPrivilegeValueA || !dyn_AdjustTokenPrivileges)
        dyn_OpenProcessToken = bad_OpenProcessToken;
    }
}