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4ac1163902
PR: bin/75258 Submitted by: "Oleg V. Nauman" <oleg@reis.zp.ua> Arrival Date: Sun Dec 19 14:50:21 GMT 2004 Reviewed by: mjg, jhb Reviewed by: jilles (earlier version) MFC after: 1 week
187 lines
5.0 KiB
C
187 lines
5.0 KiB
C
/*-
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* Copyright (c) 1991, 1993, 1994
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Keith Muller of the University of California, San Diego and Lance
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* Visser of Convex Computer Corporation.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef lint
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#if 0
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static char sccsid[] = "@(#)position.c 8.3 (Berkeley) 4/2/94";
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#endif
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#endif /* not lint */
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/types.h>
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#include <sys/mtio.h>
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#include <err.h>
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#include <errno.h>
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#include <inttypes.h>
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#include <signal.h>
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#include <unistd.h>
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#include "dd.h"
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#include "extern.h"
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/*
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* Position input/output data streams before starting the copy. Device type
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* dependent. Seekable devices use lseek, and the rest position by reading.
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* Seeking past the end of file can cause null blocks to be written to the
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* output.
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*/
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void
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pos_in(void)
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{
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off_t cnt;
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int warned;
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ssize_t nr;
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size_t bcnt;
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/* If known to be seekable, try to seek on it. */
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if (in.flags & ISSEEK) {
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errno = 0;
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if (lseek(in.fd, in.offset * in.dbsz, SEEK_CUR) == -1 &&
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errno != 0)
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err(1, "%s", in.name);
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return;
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}
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/* Don't try to read a really weird amount (like negative). */
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if (in.offset < 0)
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errx(1, "%s: illegal offset", "iseek/skip");
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/*
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* Read the data. If a pipe, read until satisfy the number of bytes
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* being skipped. No differentiation for reading complete and partial
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* blocks for other devices.
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*/
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for (bcnt = in.dbsz, cnt = in.offset, warned = 0; cnt;) {
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if ((nr = read(in.fd, in.db, bcnt)) > 0) {
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if (in.flags & ISPIPE) {
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if (!(bcnt -= nr)) {
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bcnt = in.dbsz;
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--cnt;
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}
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} else
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--cnt;
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if (need_summary)
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summary();
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continue;
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}
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if (nr == 0) {
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if (files_cnt > 1) {
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--files_cnt;
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continue;
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}
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errx(1, "skip reached end of input");
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}
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/*
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* Input error -- either EOF with no more files, or I/O error.
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* If noerror not set die. POSIX requires that the warning
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* message be followed by an I/O display.
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*/
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if (ddflags & C_NOERROR) {
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if (!warned) {
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warn("%s", in.name);
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warned = 1;
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summary();
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}
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continue;
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}
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err(1, "%s", in.name);
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}
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}
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void
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pos_out(void)
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{
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struct mtop t_op;
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off_t cnt;
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ssize_t n;
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/*
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* If not a tape, try seeking on the file. Seeking on a pipe is
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* going to fail, but don't protect the user -- they shouldn't
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* have specified the seek operand.
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*/
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if (out.flags & (ISSEEK | ISPIPE)) {
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errno = 0;
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if (lseek(out.fd, out.offset * out.dbsz, SEEK_CUR) == -1 &&
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errno != 0)
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err(1, "%s", out.name);
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return;
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}
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/* Don't try to read a really weird amount (like negative). */
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if (out.offset < 0)
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errx(1, "%s: illegal offset", "oseek/seek");
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/* If no read access, try using mtio. */
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if (out.flags & NOREAD) {
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t_op.mt_op = MTFSR;
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t_op.mt_count = out.offset;
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if (ioctl(out.fd, MTIOCTOP, &t_op) == -1)
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err(1, "%s", out.name);
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return;
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}
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/* Read it. */
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for (cnt = 0; cnt < out.offset; ++cnt) {
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if ((n = read(out.fd, out.db, out.dbsz)) > 0)
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continue;
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if (n == -1)
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err(1, "%s", out.name);
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/*
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* If reach EOF, fill with NUL characters; first, back up over
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* the EOF mark. Note, cnt has not yet been incremented, so
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* the EOF read does not count as a seek'd block.
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*/
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t_op.mt_op = MTBSR;
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t_op.mt_count = 1;
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if (ioctl(out.fd, MTIOCTOP, &t_op) == -1)
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err(1, "%s", out.name);
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while (cnt++ < out.offset) {
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n = write(out.fd, out.db, out.dbsz);
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if (n == -1)
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err(1, "%s", out.name);
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if ((size_t)n != out.dbsz)
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errx(1, "%s: write failure", out.name);
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}
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break;
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}
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}
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