wget/lib/lseek.c

63 lines
1.7 KiB
C

/* An lseek() function that detects pipes.
Copyright (C) 2007 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, 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, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
#include <config.h>
/* Specification. */
#include <unistd.h>
#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
/* Windows platforms. */
/* Get GetFileType. */
# include <windows.h>
#else
# include <sys/stat.h>
#endif
#include <errno.h>
#undef lseek
off_t
rpl_lseek (int fd, off_t offset, int whence)
{
#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
/* mingw lseek mistakenly succeeds on pipes, sockets, and terminals. */
HANDLE h = (HANDLE) _get_osfhandle (fd);
if (h == INVALID_HANDLE_VALUE)
{
errno = EBADF;
return -1;
}
if (GetFileType (h) != FILE_TYPE_DISK)
{
errno = ESPIPE;
return -1;
}
#else
/* BeOS lseek mistakenly succeeds on pipes... */
struct stat statbuf;
if (fstat (fd, &statbuf) < 0)
return -1;
if (!S_ISREG (statbuf.st_mode))
{
errno = ESPIPE;
return -1;
}
#endif
return lseek (fd, offset, whence);
}