syscalls.cc

cygwin, 著名的在win32下模拟unix操作系统的东东

    }

  if (real_b.exists ())
    {
      syscall_printf ("file '%s' exists?", (char *) real_b);
      set_errno (EEXIST);
      goto done;
    }

  if (real_b[strlen (real_b) - 1] == '.')
    {
      syscall_printf ("trailing dot, bailing out");
      set_errno (EINVAL);
      goto done;
    }

  /* Try to make hard link first on Windows NT */
  if (wincap.has_hard_links ())
    {
      if (CreateHardLinkA (real_b, real_a, NULL))
	{
	  res = 0;
	  goto done;
	}

      HANDLE hFileSource;

      WIN32_STREAM_ID StreamId;
      DWORD dwBytesWritten;
      LPVOID lpContext;
      DWORD cbPathLen;
      DWORD StreamSize;
      WCHAR wbuf[MAX_PATH];

      BOOL bSuccess;

      hFileSource = CreateFile (real_a, FILE_WRITE_ATTRIBUTES,
				FILE_SHARE_READ | FILE_SHARE_WRITE /*| FILE_SHARE_DELETE*/,
				&sec_none_nih, // sa
				OPEN_EXISTING, 0, NULL);

      if (hFileSource == INVALID_HANDLE_VALUE)
	{
	  syscall_printf ("cannot open source, %E");
	  goto docopy;
	}

      cbPathLen = sys_mbstowcs (wbuf, real_b, MAX_PATH) * sizeof (WCHAR);

      StreamId.dwStreamId = BACKUP_LINK;
      StreamId.dwStreamAttributes = 0;
      StreamId.dwStreamNameSize = 0;
      StreamId.Size.HighPart = 0;
      StreamId.Size.LowPart = cbPathLen;

      StreamSize = sizeof (WIN32_STREAM_ID) - sizeof (WCHAR**) +
		   StreamId.dwStreamNameSize;

      lpContext = NULL;
      /* Write the WIN32_STREAM_ID */
      bSuccess = BackupWrite (
	hFileSource,
	 (LPBYTE) &StreamId,	// buffer to write
	StreamSize,		// number of bytes to write
	&dwBytesWritten,
	FALSE,			// don't abort yet
	FALSE,			// don't process security
	&lpContext);

      if (bSuccess)
	{
	  /* write the buffer containing the path */
	  /* FIXME: BackupWrite sometimes traps if linkname is invalid.
	     Need to handle. */
	  bSuccess = BackupWrite (
		hFileSource,
		 (LPBYTE) wbuf,	// buffer to write
		cbPathLen,	// number of bytes to write
		&dwBytesWritten,
		FALSE,		// don't abort yet
		FALSE,		// don't process security
		&lpContext
		);

	  if (!bSuccess)
	    syscall_printf ("cannot write linkname, %E");

	  /* Free context */
	  BackupWrite (
	    hFileSource,
	    NULL,		// buffer to write
	    0,			// number of bytes to write
	    &dwBytesWritten,
	    TRUE,		// abort
	    FALSE,		// don't process security
	    &lpContext);
	}
      else
	syscall_printf ("cannot write streamId, %E");

      CloseHandle (hFileSource);

      if (!bSuccess)
	goto docopy;

      res = 0;
      goto done;
    }
docopy:
  /* do this with a copy */
  if (CopyFileA (real_a, real_b, 1))
    res = 0;
  else
    __seterrno ();

done:
  syscall_printf ("%d = link (%s, %s)", res, a, b);
  return res;
}

/* chown: POSIX 5.6.5.1 */
/*
 * chown () is only implemented for Windows NT.  Under other operating
 * systems, it is only a stub that always returns zero.
 */
static int
chown_worker (const char *name, unsigned fmode, __uid32_t uid, __gid32_t gid)
{
  int res;

  if (check_null_empty_str_errno (name))
    return -1;

  if (!wincap.has_security ())  // real chown only works on NT
    res = 0;			// return zero (and do nothing) under Windows 9x
  else
    {
      /* we need Win32 path names because of usage of Win32 API functions */
      path_conv win32_path (PC_NONULLEMPTY, name, fmode);

      if (win32_path.error)
	{
	  set_errno (win32_path.error);
	  res = -1;
	  goto done;
	}

      /* FIXME: This makes chown on a device succeed always.  Someday we'll want
	 to actually allow chown to work properly on devices. */
      if (win32_path.is_device ())
	{
	  res = 0;
	  goto done;
	}

      DWORD attrib = 0;
      if (win32_path.isdir ())
	attrib |= S_IFDIR;
      res = get_file_attribute (win32_path.has_acls (),
				win32_path.get_win32 (),
				(int *) &attrib);
      if (!res)
         res = set_file_attribute (win32_path.has_acls (), win32_path, uid,
				   gid, attrib);
      if (res != 0 && (!win32_path.has_acls () || !allow_ntsec))
	{
	  /* fake - if not supported, pretend we're like win95
	     where it just works */
	  res = 0;
	}
    }

done:
  syscall_printf ("%d = %schown (%s,...)",
		  res, (fmode & PC_SYM_NOFOLLOW) ? "l" : "", name);
  return res;
}

extern "C" int
chown32 (const char * name, __uid32_t uid, __gid32_t gid)
{
  sigframe thisframe (mainthread);
  return chown_worker (name, PC_SYM_FOLLOW, uid, gid);
}

extern "C" int
chown (const char * name, __uid16_t uid, __gid16_t gid)
{
  sigframe thisframe (mainthread);
  return chown_worker (name, PC_SYM_FOLLOW,
		       uid16touid32 (uid), gid16togid32 (gid));
}

extern "C" int
lchown32 (const char * name, __uid32_t uid, __gid32_t gid)
{
  sigframe thisframe (mainthread);
  return chown_worker (name, PC_SYM_NOFOLLOW, uid, gid);
}

extern "C" int
lchown (const char * name, __uid16_t uid, __gid16_t gid)
{
  sigframe thisframe (mainthread);
  return chown_worker (name, PC_SYM_NOFOLLOW,
		       uid16touid32 (uid), gid16togid32 (gid));
}

extern "C" int
fchown32 (int fd, __uid32_t uid, __gid32_t gid)
{
  sigframe thisframe (mainthread);
  cygheap_fdget cfd (fd);
  if (cfd < 0)
    {
      syscall_printf ("-1 = fchown (%d,...)", fd);
      return -1;
    }

  const char *path = cfd->get_name ();

  if (path == NULL)
    {
      syscall_printf ("-1 = fchown (%d,...) (no name)", fd);
      set_errno (ENOSYS);
      return -1;
    }

  syscall_printf ("fchown (%d,...): calling chown_worker (%s,FOLLOW,...)",
		  fd, path);
  return chown_worker (path, PC_SYM_FOLLOW, uid, gid);
}

extern "C" int
fchown (int fd, __uid16_t uid, __gid16_t gid)
{
  return fchown32 (fd, uid16touid32 (uid), gid16togid32 (gid));
}

/* umask: POSIX 5.3.3.1 */
extern "C" mode_t
umask (mode_t mask)
{
  mode_t oldmask;

  oldmask = cygheap->umask;
  cygheap->umask = mask & 0777;
  return oldmask;
}

/* chmod: POSIX 5.6.4.1 */
extern "C" int
chmod (const char *path, mode_t mode)
{
  int res = -1;
  sigframe thisframe (mainthread);

  path_conv win32_path (path);

  if (win32_path.error)
    {
      set_errno (win32_path.error);
      goto done;
    }

  /* FIXME: This makes chmod on a device succeed always.  Someday we'll want
     to actually allow chmod to work properly on devices. */
  if (win32_path.is_device ())
    {
      res = 0;
      goto done;
    }

  if (!win32_path.exists ())
    __seterrno ();
  else
    {
      /* temporary erase read only bit, to be able to set file security */
      SetFileAttributes (win32_path, (DWORD) win32_path & ~FILE_ATTRIBUTE_READONLY);

      if (win32_path.isdir ())
	mode |= S_IFDIR;
      if (!set_file_attribute (win32_path.has_acls (), win32_path,
			       ILLEGAL_UID, ILLEGAL_GID, mode)
	  && allow_ntsec)
	res = 0;

      /* if the mode we want has any write bits set, we can't
	 be read only. */
      if (mode & (S_IWUSR | S_IWGRP | S_IWOTH))
	(DWORD) win32_path &= ~FILE_ATTRIBUTE_READONLY;
      else
	(DWORD) win32_path |= FILE_ATTRIBUTE_READONLY;

      if (S_ISLNK (mode) || S_ISSOCK (mode))
	(DWORD) win32_path |= FILE_ATTRIBUTE_SYSTEM;

      if (!SetFileAttributes (win32_path, win32_path))
	__seterrno ();
      else if (!allow_ntsec)
	/* Correct NTFS security attributes have higher priority */
	res = 0;
    }

done:
  syscall_printf ("%d = chmod (%s, %p)", res, path, mode);
  return res;
}

/* fchmod: P96 5.6.4.1 */

extern "C" int
fchmod (int fd, mode_t mode)
{
  sigframe thisframe (mainthread);
  cygheap_fdget cfd (fd);
  if (cfd < 0)
    {
      syscall_printf ("-1 = fchmod (%d, 0%o)", fd, mode);
      return -1;
    }

  const char *path = cfd->get_name ();

  if (path == NULL)
    {
      syscall_printf ("-1 = fchmod (%d, 0%o) (no name)", fd, mode);
      set_errno (ENOSYS);
      return -1;
    }

  syscall_printf ("fchmod (%d, 0%o): calling chmod (%s, 0%o)",
		  fd, mode, path, mode);
  return chmod (path, mode);
}

static void
stat64_to_stat32 (struct __stat64 *src, struct __stat32 *dst)
{
  dst->st_dev = ((src->st_dev >> 8) & 0xff00) | (src->st_dev & 0xff);
  dst->st_ino = src->st_ino;
  dst->st_mode = src->st_mode;
  dst->st_nlink = src->st_nlink;
  dst->st_uid = src->st_uid;
  dst->st_gid = src->st_gid;
  dst->st_rdev = ((src->st_rdev >> 8) & 0xff00) | (src->st_rdev & 0xff);
  dst->st_size = src->st_size;
  dst->st_atim = src->st_atim;
  dst->st_mtim = src->st_mtim;
  dst->st_ctim = src->st_ctim;
  dst->st_blksize = src->st_blksize;
  dst->st_blocks = src->st_blocks;
}

extern "C" int
fstat64 (int fd, struct __stat64 *buf)
{
  int res;
  sigframe thisframe (mainthread);

  cygheap_fdget cfd (fd);
  if (cfd < 0)
    res = -1;
  else
    {
      path_conv pc (cfd->get_win32_name (), PC_SYM_NOFOLLOW);
      memset (buf, 0, sizeof (struct __stat64));
      res = cfd->fstat (buf, &pc);
      if (!res)
	{
	  if (!buf->st_ino)
	    buf->st_ino = hash_path_name (0, cfd->get_win32_name ());
	  if (!buf->st_dev)
	    buf->st_dev = (cfd->get_device () << 16) | cfd->get_unit ();
	  if (!buf->st_rdev)
	    buf->st_rdev = buf->st_dev;
	}
    }

  syscall_printf ("%d = fstat (%d, %p)", res, fd, buf);
  return res;
}

extern "C" int
_fstat (int fd, struct __stat32 *buf)
{
  struct __stat64 buf64;
  int ret = fstat64 (fd, &buf64);
  if (!ret)
    stat64_to_stat32 (&buf64, buf);
  return ret;
}

/* fsync: P96 6.6.1.1 */
extern "C" int
fsync (int fd)
{
  sigframe thisframe (mainthread);
  cygheap_fdget cfd (fd);
  if (cfd < 0)
    {
      syscall_printf ("-1 = fsync (%d)", fd);
      return -1;
    }

  if (FlushFileBuffers (cfd->get_handle ()) == 0)
    {
      __seterrno ();
      return -1;
    }
  return 0;
}

/* sync: standards? */
extern "C" int
sync ()
{
  return 0;
}

suffix_info stat_suffixes[] =
{
  suffix_info ("", 1),
  suffix_info (".exe", 1),
  suffix_info (NULL)
};

/* Cygwin internal */
int __stdcall
stat_worker (const char *name, struct __stat64 *buf, int nofollow,
	     path_conv *pc)
{
  int res = -1;
  path_conv real_path;
  fhandler_base *fh = NULL;

  if (check_null_invalid_struct_errno (buf))
    goto done;

  if (!pc)
    pc = &real_path;

  fh = cygheap->fdtab.build_fhandler_from_name (-1, name, NULL, *pc,
						(nofollow ? PC_SYM_NOFOLLOW
							  : PC_SYM_FOLLOW)
						| PC_FULL, stat_suffixes);

  if (pc->error)
    {
      debug_printf ("got %d error from build_fhandler_from_name", pc->error);
      set_errno (pc->error);
    }
  else
    {
      debug_printf ("(%s, %p, %d, %p), file_attributes %d", name, buf, nofollow,
		    pc, (DWORD) real_path);
      memset (buf, 0, sizeof (*buf));
      res = fh->fstat (buf, pc);
      if (!res)
	{
	  if (!buf->st_ino)
	    buf->st_ino = hash_path_name (0, fh->get_win32_name ());
	  if (!buf->st_dev)
	    buf->st_dev = (fh->get_device () << 16) | fh->get_unit ();
	  if (!buf->st_rdev)
	    buf->st_rdev = buf->st_dev;
	}
    }

 done:
  if (fh)
    delete fh;
  MALLOC_CHECK;
  syscall_printf ("%d = (%s, %p)", res, name, buf);
  return res;
}

extern "C" int
stat64 (const char *name, struct __stat64 *buf)
{
  sigframe thisframe (mainthread);
  syscall_printf ("entering");
  return stat_worker (name, buf, 0);
}

extern "C" int
_stat (const char *name, struct __stat32 *buf)
{
  struct __stat64 buf64;
  int ret = stat64 (name, &buf64);
  if (!ret)
    stat64_to_stat32 (&buf64, buf);
  return ret;
}

/* lstat: Provided by SVR4 and 4.3+BSD, POSIX? */
extern "C" int
lstat64 (const char *name, struct __stat64 *buf)
{
  sigframe thisframe (mainthread);
  syscall_printf ("entering");
  return stat_worker (name, buf, 1);
}

/* lstat: Provided by SVR4 and 4.3+BSD, POSIX? */
extern "C" int
cygwin_lstat (const char *name, struct __stat32 *buf)
{
  struct __stat64 buf64;
  int ret = lstat64 (name, &buf64);
  if (!ret)
    stat64_to_stat32 (&buf64, buf);
  return ret;
}

extern int acl_access (const char *, int);

extern "C" int
access (const char *fn, int flags)
{
  sigframe thisframe (mainthread);
  // flags were incorrectly specified
  if (flags & ~(F_OK|R_OK|W_OK|X_OK))
    {
      set_errno (EINVAL);
      return -1;
    }

  if (allow_ntsec)
    return acl_access (fn, flags);

  struct __stat64 st;
  int r = stat_worker (fn, &st, 0);
  if (r)
    return -1;
  r = -1;
  if (flags & R_OK)
    {
      if (st.st_uid == myself->uid)
	{
	  if (!(st.st_mode & S_IRUSR))
	    goto done;
	}
      else if (st.st_gid == myself->gid)
	{
	  if (!(st.st_mode & S_IRGRP))
	    goto done;
	}
      else if (!(st.st_mode & S_IROTH))
	goto done;
    }
  if (flags & W_OK)
    {
      if (st.st_uid == myself->uid)
	{
	  if (!(st.st_mode & S_IWUSR))
	    goto done;
	}
      else if (st.st_gid == myself->gid)
	{
	  if (!(st.st_mode & S_IWGRP))
	    goto done;
	}
      else if (!(st.st_mode & S_IWOTH))
	goto done;
    }
  if (flags & X_OK)
    {
      if (st.st_uid == myself->uid)
	{
	  if (!(st.st_mode & S_IXUSR))
	    goto done;
	}
      else if (st.st_gid == myself->gid)
	{
	  if (!(st.st_mode & S_IXGRP))
	    goto done;
	}
      else if (!(st.st_mode & S_IXOTH))
	goto done;
    }
  r = 0;
done:
  if (r)
    set_errno (EACCES);
  return r;
}

extern "C" int
rename (const char *oldpath, const char *newpath)
{
  sigframe thisframe (mainthread);
  int res = 0;
  char *lnk_suffix = NULL;

  path_conv real_old (oldpath, PC_SYM_NOFOLLOW);

  if (real_old.error)
    {
      syscall_printf ("-1 = rename (%s, %s)", oldpath, newpath);
      set_errno (real_old.error);
      return -1;
    }

  path_conv real_new (newpath, PC_SYM_NOFOLLOW);

  /* Shortcut hack. */
  char new_lnk_buf[MAX_PATH + 5];
  if (real_old.issymlink () && !real_new.error && !real_new.case_clash)
    {
      int len_old = strlen (real_old.get_win32 ());
      if (strcasematch (real_old.get_win32 () + len_old - 4, ".lnk"))
	{
	  strcpy (new_lnk_buf, newpath);
	  strcat (new_lnk_buf, ".lnk");
	  newpath = new_lnk_buf;
	  real_new.check (newpath, PC_SYM_NOFOLLOW);
	}
    }

  if (real_new.error || real_new.case_clash)
    {
      syscall_printf ("-1 = rename (%s, %s)", oldpath, newpath);
      set_errno (real_new.case_clash ? ECASECLASH : real_new.error);
      return -1;
    }

  if (!writable_directory (real_old) || !writable_directory (real_new))
    {
      syscall_printf ("-1 = rename (%s, %s)", oldpath, newpath);
      set_errno (EACCES);
      return -1;
    }

  if (!real_old.exists ()) /* file to move doesn't exist */
    {
       syscall_printf ("file to move doesn't exist");
       set_errno (ENOENT);
       return (-1);
    }

  /* Destination file exists and is read only, change that or else
     the rename won't work. */
  if (real_new.has_attribute (FILE_ATTRIBUTE_READONLY))
    SetFileAttributes (real_new, (DWORD) real_new & ~FILE_ATTRIBUTE_READONLY);

  /* Shortcut hack No. 2, part 1 */
  if (!real_old.issymlink () && !real_new.error && real_new.issymlink () &&
      real_new.known_suffix && strcasematch (real_new.known_suffix, ".lnk") &&