GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: bin/dd/position.c Lines: 0 41 0.0 %
Date: 2016-12-06 Branches: 0 42 0.0 %

Line Branch Exec Source
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/*	$OpenBSD: position.c,v 1.10 2009/10/27 23:59:21 deraadt Exp $	*/
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/*	$NetBSD: position.c,v 1.4 1995/03/21 09:04:12 cgd Exp $	*/
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/*-
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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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 * 3. 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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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/ioctl.h>
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#include <sys/mtio.h>
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#include <sys/time.h>
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#include <err.h>
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#include <errno.h>
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#include <string.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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	size_t bcnt;
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	ssize_t nr;
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	off_t cnt;
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	int warned;
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	/* If not a pipe, tape or tty device, try to seek on it. */
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	if (!(in.flags & (ISPIPE|ISTAPE)) && !isatty(in.fd)) {
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		if (lseek(in.fd, in.offset * in.dbsz, SEEK_CUR) == -1)
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			err(1, "%s", in.name);
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		return;
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	}
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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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			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 & ISTAPE)) {
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		if (lseek(out.fd, out.offset * out.dbsz, SEEK_SET) == -1)
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			err(1, "%s", out.name);
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		return;
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	}
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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) < 0)
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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 < 0)
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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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			if ((n = write(out.fd, out.db, out.dbsz)) != out.dbsz)
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				err(1, "%s", out.name);
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		break;
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	}
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}