/* Work around rename bugs in some systems.

   Copyright (C) 2001, 2002, 2003, 2005, 2006, 2009 Free Software
   Foundation, Inc.

   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/>.  */

/* Written by Volker Borchert, Eric Blake.  */

#include <config.h>

#include <stdio.h>

#undef rename

#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
/* The mingw rename has problems with trailing slashes; it also
   requires use of native Windows calls to allow atomic renames over
   existing files.  */

# include <errno.h>

# define WIN32_LEAN_AND_MEAN
# include <windows.h>

/* Rename the file SRC to DST.  This replacement is necessary on
   Windows, on which the system rename function will not replace
   an existing DST.  */
int
rpl_rename (char const *src, char const *dst)
{
  int error;

  /* MoveFileEx works if SRC is a directory without any flags,
     but fails with MOVEFILE_REPLACE_EXISTING, so try without
     flags first. */
  if (MoveFileEx (src, dst, 0))
    return 0;

  /* Retry with MOVEFILE_REPLACE_EXISTING if the move failed
   * due to the destination already existing. */
  error = GetLastError ();
  if (error == ERROR_FILE_EXISTS || error == ERROR_ALREADY_EXISTS)
    {
      if (MoveFileEx (src, dst, MOVEFILE_REPLACE_EXISTING))
        return 0;

      error = GetLastError ();
    }

  switch (error)
    {
    case ERROR_FILE_NOT_FOUND:
    case ERROR_PATH_NOT_FOUND:
    case ERROR_BAD_PATHNAME:
    case ERROR_DIRECTORY:
      errno = ENOENT;
      break;

    case ERROR_ACCESS_DENIED:
    case ERROR_SHARING_VIOLATION:
      errno = EACCES;
      break;

    case ERROR_OUTOFMEMORY:
      errno = ENOMEM;
      break;

    case ERROR_CURRENT_DIRECTORY:
      errno = EBUSY;
      break;

    case ERROR_NOT_SAME_DEVICE:
      errno = EXDEV;
      break;

    case ERROR_WRITE_PROTECT:
      errno = EROFS;
      break;

    case ERROR_WRITE_FAULT:
    case ERROR_READ_FAULT:
    case ERROR_GEN_FAILURE:
      errno = EIO;
      break;

    case ERROR_HANDLE_DISK_FULL:
    case ERROR_DISK_FULL:
    case ERROR_DISK_TOO_FRAGMENTED:
      errno = ENOSPC;
      break;

    case ERROR_FILE_EXISTS:
    case ERROR_ALREADY_EXISTS:
      errno = EEXIST;
      break;

    case ERROR_BUFFER_OVERFLOW:
    case ERROR_FILENAME_EXCED_RANGE:
      errno = ENAMETOOLONG;
      break;

    case ERROR_INVALID_NAME:
    case ERROR_DELETE_PENDING:
      errno = EPERM;        /* ? */
      break;

# ifndef ERROR_FILE_TOO_LARGE
/* This value is documented but not defined in all versions of windows.h. */
#  define ERROR_FILE_TOO_LARGE 223
# endif
    case ERROR_FILE_TOO_LARGE:
      errno = EFBIG;
      break;

    default:
      errno = EINVAL;
      break;
    }

  return -1;
}

#else /* ! W32 platform */

# include <errno.h>
# include <stdio.h>
# include <stdlib.h>
# include <string.h>
# include <sys/stat.h>

# include "dirname.h"
# include "same-inode.h"

/* Rename the file SRC to DST, fixing any trailing slash bugs.  */

int
rpl_rename (char const *src, char const *dst)
{
  size_t src_len = strlen (src);
  size_t dst_len = strlen (dst);
  char *src_temp = (char *) src;
  char *dst_temp = (char *) dst;
  bool src_slash;
  bool dst_slash;
  int ret_val = -1;
  int rename_errno = ENOTDIR;
  struct stat src_st;
  struct stat dst_st;

  if (!src_len || !dst_len)
    return rename (src, dst); /* Let strace see the ENOENT failure.  */

# if RENAME_DEST_EXISTS_BUG
  {
    char *src_base = last_component (src);
    char *dst_base = last_component (dst);
    if (*src_base == '.')
      {
        size_t len = base_len (src_base);
        if (len == 1 || (len == 2 && src_base[1] == '.'))
          {
            errno = EINVAL;
            return -1;
          }
      }
    if (*dst_base == '.')
      {
        size_t len = base_len (dst_base);
        if (len == 1 || (len == 2 && dst_base[1] == '.'))
          {
            errno = EINVAL;
            return -1;
          }
      }
  }
# endif /* RENAME_DEST_EXISTS_BUG */

  src_slash = src[src_len - 1] == '/';
  dst_slash = dst[dst_len - 1] == '/';

# if !RENAME_DEST_EXISTS_BUG
  /* If there are no trailing slashes, then trust the native
     implementation unless we also suspect issues with hard link
     detection.  */
  if (!src_slash && !dst_slash)
    return rename (src, dst);
# endif /* !RENAME_DEST_EXISTS_BUG */

  /* Presence of a trailing slash requires directory semantics.  If
     the source does not exist, or if the destination cannot be turned
     into a directory, give up now.  Otherwise, strip trailing slashes
     before calling rename.  */
  if (lstat (src, &src_st))
    return -1;
  if (lstat (dst, &dst_st))
    {
      if (errno != ENOENT || (!S_ISDIR (src_st.st_mode) && dst_slash))
        return -1;
    }
  else
    {
      if (S_ISDIR (dst_st.st_mode) != S_ISDIR (src_st.st_mode))
	{
	  errno = S_ISDIR (dst_st.st_mode) ? EISDIR : ENOTDIR;
	  return -1;
	}
# if RENAME_DEST_EXISTS_BUG
      if (SAME_INODE (src_st, dst_st))
	return 0;
# endif /* RENAME_DEST_EXISTS_BUG */
    }

# if RENAME_TRAILING_SLASH_SOURCE_BUG || RENAME_DEST_EXISTS_BUG
  /* If the only bug was that a trailing slash was allowed on a
     non-existing file destination, as in Solaris 10, then we've
     already covered that situation.  But if there is any problem with
     a trailing slash on an existing source or destination, as in
     Solaris 9, or if a directory can overwrite a symlink, as on
     Cygwin 1.5, or if directories cannot be created with trailing
     slash, as on NetBSD 1.6, then we must strip the offending slash
     and check that we have not encountered a symlink instead of a
     directory.

     Stripping a trailing slash interferes with POSIX semantics, where
     rename behavior on a symlink with a trailing slash operates on
     the corresponding target directory.  We prefer the GNU semantics
     of rejecting any use of a symlink with trailing slash, but do not
     enforce them, since Solaris 10 is able to obey POSIX semantics
     and there might be clients expecting it, as counter-intuitive as
     those semantics are.

     Technically, we could also follow the POSIX behavior by chasing a
     readlink trail, but that is harder to implement.  */
  if (src_slash)
    {
      src_temp = strdup (src);
      if (!src_temp)
        {
          /* Rather than rely on strdup-posix, we set errno ourselves.  */
          rename_errno = ENOMEM;
          goto out;
        }
      strip_trailing_slashes (src_temp);
      if (lstat (src_temp, &src_st))
        {
          rename_errno = errno;
          goto out;
        }
      if (S_ISLNK (src_st.st_mode))
        goto out;
    }
  if (dst_slash)
    {
      dst_temp = strdup (dst);
      if (!dst_temp)
        {
          rename_errno = ENOMEM;
          goto out;
        }
      strip_trailing_slashes (dst_temp);
      if (lstat (dst_temp, &dst_st))
        {
          if (errno != ENOENT)
            {
              rename_errno = errno;
              goto out;
            }
        }
      else if (S_ISLNK (dst_st.st_mode))
        goto out;
    }
# endif /* RENAME_TRAILING_SLASH_SOURCE_BUG || RENAME_DEST_EXISTS_BUG */

  ret_val = rename (src_temp, dst_temp);
  rename_errno = errno;
 out:
  if (src_temp != src)
    free (src_temp);
  if (dst_temp != dst)
    free (dst_temp);
  errno = rename_errno;
  return ret_val;
}
#endif /* ! W32 platform */