77 lines
2.5 KiB
C
77 lines
2.5 KiB
C
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/* Copyright (C) 1991, 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If
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not, write to the Free Software Foundation, Inc., 675 Mass Ave,
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Cambridge, MA 02139, USA. */
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#include <ansidecl.h>
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#include <unistd.h>
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#include <hurd.h>
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#include <hurd/paths.h>
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#include <fcntl.h>
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#include <string.h>
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/* Read the contents of the symbolic link FILE_NAME into no more than
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LEN bytes of BUF. The contents are not null-terminated.
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Returns the number of characters read, or -1 for errors. */
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ssize_t
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DEFUN(__readlink, (file_name, buf, len),
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CONST char *file_name AND char *buf AND size_t len)
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{
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error_t err;
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file_t file;
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char mybuf[2048], *transp = mybuf;
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mach_msg_type_number_t translen = sizeof (mybuf);
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file = __file_name_lookup (file_name, O_NOTRANS, 0);
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if (file == MACH_PORT_NULL)
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return -1;
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err = __file_get_translator (file, &transp, &translen);
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__mach_port_deallocate (__mach_task_self (), file);
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if (err)
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return __hurd_fail (err);
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if (translen < sizeof (_HURD_SYMLINK) ||
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memcmp (transp, _HURD_SYMLINK, sizeof (_HURD_SYMLINK)))
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/* The file is not actually a symlink. */
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err = EINVAL;
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else
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{
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/* This is a symlink; its translator is "/hurd/symlink\0target\0". */
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if (len >= translen - sizeof (_HURD_SYMLINK))
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{
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len = translen - sizeof (_HURD_SYMLINK);
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if (transp[translen - 1] == '\0')
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/* Remove the null terminator. */
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--len;
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}
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if (buf == NULL)
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/* This call is just to find out how large a buffer is required. */
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len = translen - sizeof (_HURD_SYMLINK) - 1;
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else
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/* Copy into the user's buffer. */
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memcpy (buf, transp + sizeof (_HURD_SYMLINK), len);
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}
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if (transp != mybuf)
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__vm_deallocate (__mach_task_self (), (vm_address_t) transp, translen);
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return err ? __hurd_fail (err) : len;
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}
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weak_alias (__readlink, readlink)
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