diff --git a/stand/libsa/lseek.c b/stand/libsa/lseek.c index df2591acd76d..1a39eb31421b 100644 --- a/stand/libsa/lseek.c +++ b/stand/libsa/lseek.c @@ -1,141 +1,142 @@ /* $NetBSD: lseek.c,v 1.4 1997/01/22 00:38:10 cgd Exp $ */ /*- * Copyright (c) 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * The Mach Operating System project at Carnegie-Mellon University. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)lseek.c 8.1 (Berkeley) 6/11/93 - * + * * * Copyright (c) 1989, 1990, 1991 Carnegie Mellon University * All Rights Reserved. * * Author: Alessandro Forin - * + * * Permission to use, copy, modify and distribute this software and its * documentation is hereby granted, provided that both the copyright * notice and this permission notice appear in all copies of the * software, derivative works or modified versions, and any portions * thereof, and that both notices appear in supporting documentation. - * + * * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. - * + * * Carnegie Mellon requests users of this software to return to - * + * * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU * School of Computer Science * Carnegie Mellon University * Pittsburgh PA 15213-3890 - * + * * any improvements or extensions that they make and grant Carnegie the * rights to redistribute these changes. */ #include __FBSDID("$FreeBSD$"); #include "stand.h" off_t lseek(int fd, off_t offset, int where) { - off_t bufpos, filepos, target; - struct open_file *f = &files[fd]; + off_t bufpos, filepos, target; + struct open_file *f = &files[fd]; - if ((unsigned)fd >= SOPEN_MAX || f->f_flags == 0) { - errno = EBADF; - return (-1); - } - - if (f->f_flags & F_RAW) { - /* - * On RAW devices, update internal offset. - */ - switch (where) { - case SEEK_SET: - f->f_offset = offset; - break; - case SEEK_CUR: - f->f_offset += offset; - break; - default: - errno = EOFFSET; - return (-1); + if ((unsigned)fd >= SOPEN_MAX || f->f_flags == 0) { + errno = EBADF; + return (-1); } - return (f->f_offset); - } - /* - * If there is some unconsumed data in the readahead buffer and it - * contains the desired offset, simply adjust the buffer offset and - * length. We don't bother with SEEK_END here, since the code to - * handle it would fail in the same cases where the non-readahead - * code fails (namely, for streams which cannot seek backward and whose - * size isn't known in advance). - */ - if (f->f_ralen != 0 && where != SEEK_END) { - if ((filepos = (f->f_ops->fo_seek)(f, (off_t)0, SEEK_CUR)) == -1) - return (-1); - bufpos = filepos - f->f_ralen; - switch (where) { - case SEEK_SET: - target = offset; - break; - case SEEK_CUR: - target = bufpos + offset; - break; - default: - errno = EINVAL; - return (-1); + if (f->f_flags & F_RAW) { + /* + * On RAW devices, update internal offset. + */ + switch (where) { + case SEEK_SET: + f->f_offset = offset; + break; + case SEEK_CUR: + f->f_offset += offset; + break; + default: + errno = EOFFSET; + return (-1); + } + return (f->f_offset); } - if (bufpos <= target && target < filepos) { - f->f_raoffset += target - bufpos; - f->f_ralen -= target - bufpos; - return (target); + + /* + * If there is some unconsumed data in the readahead buffer and it + * contains the desired offset, simply adjust the buffer offset and + * length. We don't bother with SEEK_END here, since the code to + * handle it would fail in the same cases where the non-readahead + * code fails (namely, for streams which cannot seek backward and whose + * size isn't known in advance). + */ + if (f->f_ralen != 0 && where != SEEK_END) { + filepos = (f->f_ops->fo_seek)(f, 0, SEEK_CUR); + if (filepos == -1) + return (-1); + bufpos = filepos - f->f_ralen; + switch (where) { + case SEEK_SET: + target = offset; + break; + case SEEK_CUR: + target = bufpos + offset; + break; + default: + errno = EINVAL; + return (-1); + } + if (bufpos <= target && target < filepos) { + f->f_raoffset += target - bufpos; + f->f_ralen -= target - bufpos; + return (target); + } } - } - /* - * If this is a relative seek, we need to correct the offset for - * bytes that we have already read but the caller doesn't know - * about. - */ - if (where == SEEK_CUR) - offset -= f->f_ralen; + /* + * If this is a relative seek, we need to correct the offset for + * bytes that we have already read but the caller doesn't know + * about. + */ + if (where == SEEK_CUR) + offset -= f->f_ralen; - /* - * Invalidate the readahead buffer. - */ - f->f_ralen = 0; + /* + * Invalidate the readahead buffer. + */ + f->f_ralen = 0; - return (f->f_ops->fo_seek)(f, offset, where); + return (f->f_ops->fo_seek)(f, offset, where); }