uclibc-ng/libc/unistd/fpathconf.c

/* fpathconf -- adjusted for busybox
   Copyright (C) 1991,95,96,98,99,2000,2001 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#include <errno.h>
#include <unistd.h>
#include <limits.h>
#include <stddef.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/statfs.h>


#ifndef __USE_FILE_OFFSET64
extern int fstatfs (int __fildes, struct statfs *__buf)
     __THROW __nonnull ((2));
#else
# ifdef __REDIRECT_NTH
	 extern int __REDIRECT_NTH (fstatfs, (int __fildes, struct statfs *__buf),
	                            fstatfs64) __nonnull ((2));
# else
#  define fstatfs fstatfs64
# endif
#endif

extern __typeof(fstatfs) __libc_fstatfs;

/* The Linux kernel headers mention this as a kind of generic value.  */
#define LINUX_LINK_MAX	127


/* Get file-specific information about descriptor FD.  */
long int fpathconf(int fd, int name)
{
    if (fd < 0)
    {
	__set_errno (EBADF);
	return -1;
    }

    if (name == _PC_LINK_MAX)
    {
	/* Cut some corners */
#if 0
	struct statfs fsbuf;

	/* Determine the filesystem type.  */
	if (__libc_fstatfs (fd, &fsbuf) < 0)
	{
	    if (errno == ENOSYS)
		/* not possible, return the default value.  */
		return LINUX_LINK_MAX;

	    /* Some error occured.  */
	    return -1;
	}

	switch (fsbuf.f_type)
	{
	    case EXT2_SUPER_MAGIC:
		return EXT2_LINK_MAX;

	    case MINIX_SUPER_MAGIC:
	    case MINIX_SUPER_MAGIC2:
		return MINIX_LINK_MAX;

	    case MINIX2_SUPER_MAGIC:
	    case MINIX2_SUPER_MAGIC2:
		return MINIX2_LINK_MAX;

	    case XENIX_SUPER_MAGIC:
		return XENIX_LINK_MAX;

	    case SYSV4_SUPER_MAGIC:
	    case SYSV2_SUPER_MAGIC:
		return SYSV_LINK_MAX;

	    case COH_SUPER_MAGIC:
		return COH_LINK_MAX;

	    case UFS_MAGIC:
	    case UFS_CIGAM:
		return UFS_LINK_MAX;

	    case REISERFS_SUPER_MAGIC:
		return REISERFS_LINK_MAX;

	    default:
		return LINUX_LINK_MAX;
	}
#else
	return LINUX_LINK_MAX;
#endif
    }

    switch (name)
    {
	default:
	    __set_errno (EINVAL);
	    return -1;

	case _PC_MAX_CANON:
#ifdef	MAX_CANON
	    return MAX_CANON;
#else
	    return -1;
#endif

	case _PC_MAX_INPUT:
#ifdef	MAX_INPUT
	    return MAX_INPUT;
#else
	    return -1;
#endif

	case _PC_NAME_MAX:
#ifdef	NAME_MAX
	    {
		struct statfs buf;
		int save_errno = errno;

		if (__libc_fstatfs (fd, &buf) < 0)
		{
		    if (errno == ENOSYS)
		    {
			errno = save_errno;
			return NAME_MAX;
		    }
		    return -1;
		}
		else
		{
#ifdef _STATFS_F_NAMELEN
		    return buf.f_namelen;
#else
# ifdef _STATFS_F_NAME_MAX
		    return buf.f_name_max;
# else
		    return NAME_MAX;
# endif
#endif
		}
	    }
#else
	    return -1;
#endif

	case _PC_PATH_MAX:
#ifdef	PATH_MAX
	    return PATH_MAX;
#else
	    return -1;
#endif

	case _PC_PIPE_BUF:
#ifdef	PIPE_BUF
	    return PIPE_BUF;
#else
	    return -1;
#endif

	case _PC_CHOWN_RESTRICTED:
#ifdef	_POSIX_CHOWN_RESTRICTED
	    return _POSIX_CHOWN_RESTRICTED;
#else
	    return -1;
#endif

	case _PC_NO_TRUNC:
#ifdef	_POSIX_NO_TRUNC
	    return _POSIX_NO_TRUNC;
#else
	    return -1;
#endif

	case _PC_VDISABLE:
#ifdef	_POSIX_VDISABLE
	    return _POSIX_VDISABLE;
#else
	    return -1;
#endif

	case _PC_SYNC_IO:
#ifdef	_POSIX_SYNC_IO
	    return _POSIX_SYNC_IO;
#else
	    return -1;
#endif

	case _PC_ASYNC_IO:
#if defined _POSIX_ASYNC_IO
	    {
		/* AIO is only allowed on regular files and block devices.  */
		struct stat st;

		if (fstat (fd, &st) < 0 || (! S_ISREG (st.st_mode) && ! S_ISBLK (st.st_mode)))
		    return -1;
		else
		    return 1;
	    }
#else
	    return -1;
#endif

	case _PC_PRIO_IO:
#ifdef	_POSIX_PRIO_IO
	    return _POSIX_PRIO_IO;
#else
	    return -1;
#endif

	case _PC_SOCK_MAXBUF:
#ifdef	SOCK_MAXBUF
	    return SOCK_MAXBUF;
#else
	    return -1;
#endif

	case _PC_FILESIZEBITS:
#ifdef FILESIZEBITS
	    return FILESIZEBITS;
#else
	    /* We let platforms with larger file sizes overwrite this value.  */
	    return 32;
#endif

	    /* Be lazy -- skip these */
	case _PC_REC_INCR_XFER_SIZE:
	case _PC_REC_MAX_XFER_SIZE:
	case _PC_REC_MIN_XFER_SIZE:
	case _PC_REC_XFER_ALIGN:
	case _PC_ALLOC_SIZE_MIN:
	case _PC_SYMLINK_MAX:
	    return -1;
    }

}