/* fhandler_netdrive.cc: fhandler for // and //MACHINE handling

   Copyright 2005 Red Hat, Inc.

This file is part of Cygwin.

This software is a copyrighted work licensed under the terms of the
Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
details. */

#include "winsup.h"
#include <unistd.h>
#include <stdlib.h>
#include <sys/cygwin.h>
#include "cygerrno.h"
#include "security.h"
#include "path.h"
#include "fhandler.h"
#include "dtable.h"
#include "cygheap.h"
#include "sigproc.h"
#include "cygthread.h"
#include <assert.h>
#include <winnetwk.h>

#include <dirent.h>

enum
  {
    GET_RESOURCE_INFO = 0,
    GET_RESOURCE_OPENENUM = 1,
    GET_RESOURCE_OPENENUMTOP = 2,
    GET_RESOURCE_ENUM = 3
  };

struct netdriveinf
  {
    int what;
    int ret;
    PVOID in;
    PVOID out;
    DWORD outsize;
    HANDLE sem;
  };

static DWORD WINAPI
thread_netdrive (void *arg)
{
  netdriveinf *ndi = (netdriveinf *) arg;
  LPTSTR dummy = NULL;
  LPNETRESOURCE nro, nro2;
  DWORD size;
  HANDLE enumhdl;

  ReleaseSemaphore (ndi->sem, 1, NULL);
  switch (ndi->what)
    {
    case GET_RESOURCE_INFO:
      nro = (LPNETRESOURCE) alloca (size = 4096);
      ndi->ret = WNetGetResourceInformation ((LPNETRESOURCE) ndi->in,
					     nro, &size, &dummy);
      break;
    case GET_RESOURCE_OPENENUM:
    case GET_RESOURCE_OPENENUMTOP:
      nro = (LPNETRESOURCE) alloca (size = 4096);
      ndi->ret = WNetGetResourceInformation ((LPNETRESOURCE) ndi->in,
					     nro, &size, &dummy);
      if (ndi->ret != NO_ERROR)
        break;
      if (ndi->what == GET_RESOURCE_OPENENUMTOP)
        {
	  nro2 = nro;
	  nro = (LPNETRESOURCE) alloca (size = 4096);
	  ndi->ret = WNetGetResourceParent (nro2, nro, &size);
	  if (ndi->ret != NO_ERROR)
	    break;
	}
      ndi->ret = WNetOpenEnum (RESOURCE_GLOBALNET, RESOURCETYPE_DISK, 0, nro,
			       &enumhdl);
      if (ndi->ret == NO_ERROR)
        *(HANDLE *) ndi->out = enumhdl;
      break;
    case GET_RESOURCE_ENUM:
      ndi->ret = WNetEnumResource ((HANDLE) ndi->in, (size = 1, &size),
				   (LPNETRESOURCE) ndi->out, &ndi->outsize);
      break;
    }
  ReleaseSemaphore (ndi->sem, 1, NULL);
  return 0;
}

static DWORD
create_thread_and_wait (int what, PVOID in, PVOID out, DWORD outsize,
			const char *name)
{
  netdriveinf ndi = { what, 0, in, out, outsize,
		      CreateSemaphore (&sec_none_nih, 0, 2, NULL) };
  cygthread *thr = new cygthread (thread_netdrive, (LPVOID) &ndi, name);
  if (thr->detach (ndi.sem))
    ndi.ret = ERROR_OPERATION_ABORTED;
  CloseHandle (ndi.sem);
  return ndi.ret;
}

/* Returns 0 if path doesn't exist, >0 if path is a directory,
   -1 if path is a file, -2 if it's a symlink.  */
int
fhandler_netdrive::exists ()
{
  char *to;
  const char *from;
  size_t len = strlen (get_name ());
  if (len == 2)
    return 1;
  char namebuf[len + 1];
  for (to = namebuf, from = get_name (); *from; to++, from++)
    *to = (*from == '/') ? '\\' : *from;
  *to = '\0';

  NETRESOURCE nr = {0};
  nr.dwScope = RESOURCE_GLOBALNET;
  nr.dwType = RESOURCETYPE_DISK;
  nr.lpLocalName = NULL;
  nr.lpRemoteName = namebuf;
  DWORD ret = create_thread_and_wait (GET_RESOURCE_INFO, &nr, NULL, 0,
				      "WNetGetResourceInformation");
  if (ret != ERROR_MORE_DATA && ret != NO_ERROR)
    return 0;
  return 1;
}

fhandler_netdrive::fhandler_netdrive ():
  fhandler_virtual ()
{
}

int
fhandler_netdrive::fstat (struct __stat64 *buf)
{
  const char *path = get_name ();
  debug_printf ("fstat (%s)", path);

  (void) fhandler_base::fstat (buf);

  buf->st_mode = S_IFDIR | STD_RBITS | STD_XBITS;

  return 0;
}

struct dirent *
fhandler_netdrive::readdir (DIR *dir)
{
  DWORD size;
  NETRESOURCE *nro;
  DWORD ret;

  if (!dir->__d_position)
    {
      size_t len = strlen (get_name ());
      char *namebuf;
      NETRESOURCE nr = { 0 };

      if (len == 2)	/* // */
        {
	  namebuf = (char *) alloca (MAX_COMPUTERNAME_LENGTH + 3);
	  strcpy (namebuf, "\\\\");
	  size = MAX_COMPUTERNAME_LENGTH + 1;
	  if (!GetComputerName (namebuf + 2, &size))
	    {
	      __seterrno ();
	      return NULL;
	    }
	}
      else
        {
	  const char *from;
	  char *to;
	  namebuf = (char *) alloca (len + 1);
	  for (to = namebuf, from = get_name (); *from; to++, from++)
	    *to = (*from == '/') ? '\\' : *from;
	  *to = '\0';
	}

      nr.lpRemoteName = namebuf;
      nr.dwType = RESOURCETYPE_DISK;
      nro = (NETRESOURCE *) alloca (4096);
      ret = create_thread_and_wait (len == 2 ? GET_RESOURCE_OPENENUMTOP
					     : GET_RESOURCE_OPENENUM,
				    &nr, &dir->__handle, 0, "WNetOpenEnum");
      if (ret != NO_ERROR)
	{
	  __seterrno_from_win_error (ret);
	  dir->__handle = INVALID_HANDLE_VALUE;
	  return NULL;
	}
    }
  ret = create_thread_and_wait (GET_RESOURCE_ENUM, dir->__handle,
  				nro = (LPNETRESOURCE) alloca (16384),
				16384, "WnetEnumResource");
  if (ret != NO_ERROR)
    {
      if (ret != ERROR_NO_MORE_ITEMS)
	__seterrno_from_win_error (ret);
      return NULL;
    }
  dir->__d_position++;
  char *bs = strrchr (nro->lpRemoteName, '\\');
  strcpy (dir->__d_dirent->d_name, bs ? bs + 1 : nro->lpRemoteName);
  return dir->__d_dirent;
}

void
fhandler_netdrive::seekdir (DIR *dir, _off64_t pos)
{
  rewinddir (dir);
  if (pos < 0)
    return;
  while (dir->__d_position < pos)
    if (!readdir (dir))
      break;
}

void
fhandler_netdrive::rewinddir (DIR *dir)
{
  if (dir->__handle != INVALID_HANDLE_VALUE)
    WNetCloseEnum (dir->__handle);
  dir->__handle = INVALID_HANDLE_VALUE;
  return fhandler_virtual::rewinddir (dir);
}

int
fhandler_netdrive::closedir (DIR *dir)
{
  rewinddir (dir);
  return fhandler_virtual::closedir (dir);
}

int
fhandler_netdrive::open (int flags, mode_t mode)
{
  int res = fhandler_virtual::open (flags, mode);
  if (!res)
    goto out;

  nohandle (true);

  if ((flags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
    {
      set_errno (EEXIST);
      res = 0;
      goto out;
    }
  else if (flags & O_WRONLY)
    {
      set_errno (EISDIR);
      res = 0;
      goto out;
    }

  res = 1;
  set_flags ((flags & ~O_TEXT) | O_BINARY | O_DIROPEN);
  set_open_status ();
out:
  syscall_printf ("%d = fhandler_netdrive::open (%p, %d)", res, flags, mode);
  return res;
}