Merge branch 'vendor/OPENSSL'
[dragonfly.git] / bin / dd / position.c
CommitLineData
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1/*-
2 * Copyright (c) 1991, 1993, 1994
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Keith Muller of the University of California, San Diego and Lance
7 * Visser of Convex Computer Corporation.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
1902d433 17 * 3. Neither the name of the University nor the names of its contributors
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18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
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32 *
33 * @(#)position.c 8.3 (Berkeley) 4/2/94
34 * $FreeBSD: src/bin/dd/position.c,v 1.17.2.2 2001/01/23 14:23:55 asmodai Exp $
1902d433 35 * $DragonFly: src/bin/dd/position.c,v 1.4 2008/01/28 16:08:02 matthias Exp $
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36 */
37
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38#include <sys/types.h>
39#include <sys/mtio.h>
40
41#include <err.h>
42#include <errno.h>
43#include <unistd.h>
44
45#include "dd.h"
46#include "extern.h"
47
48/*
49 * Position input/output data streams before starting the copy. Device type
50 * dependent. Seekable devices use lseek, and the rest position by reading.
51 * Seeking past the end of file can cause null blocks to be written to the
52 * output.
53 */
54void
b5744197 55pos_in(void)
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56{
57 off_t cnt;
58 int warned;
59 ssize_t nr;
60 size_t bcnt;
61
62 /* If known to be seekable, try to seek on it. */
63 if (in.flags & ISSEEK) {
64 errno = 0;
65 if (lseek(in.fd, in.offset * in.dbsz, SEEK_CUR) == -1 &&
66 errno != 0)
67 err(1, "%s", in.name);
68 return;
69 }
70
71 /* Don't try to read a really weird amount (like negative). */
72 if (in.offset < 0)
73 errx(1, "%s: illegal offset", "iseek/skip");
74
75 /*
76 * Read the data. If a pipe, read until satisfy the number of bytes
77 * being skipped. No differentiation for reading complete and partial
78 * blocks for other devices.
79 */
80 for (bcnt = in.dbsz, cnt = in.offset, warned = 0; cnt;) {
81 if ((nr = read(in.fd, in.db, bcnt)) > 0) {
82 if (in.flags & ISPIPE) {
83 if (!(bcnt -= nr)) {
84 bcnt = in.dbsz;
85 --cnt;
86 }
87 } else
88 --cnt;
89 continue;
90 }
91
92 if (nr == 0) {
93 if (files_cnt > 1) {
94 --files_cnt;
95 continue;
96 }
97 errx(1, "skip reached end of input");
98 }
99
100 /*
101 * Input error -- either EOF with no more files, or I/O error.
102 * If noerror not set die. POSIX requires that the warning
103 * message be followed by an I/O display.
104 */
105 if (ddflags & C_NOERROR) {
106 if (!warned) {
107 warn("%s", in.name);
108 warned = 1;
109 summary();
110 }
111 continue;
112 }
113 err(1, "%s", in.name);
114 }
115}
116
117void
b5744197 118pos_out(void)
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119{
120 struct mtop t_op;
121 off_t cnt;
122 ssize_t n;
123
124 /*
125 * If not a tape, try seeking on the file. Seeking on a pipe is
126 * going to fail, but don't protect the user -- they shouldn't
127 * have specified the seek operand.
128 */
129 if (out.flags & (ISSEEK | ISPIPE)) {
130 errno = 0;
131 if (lseek(out.fd, out.offset * out.dbsz, SEEK_CUR) == -1 &&
132 errno != 0)
133 err(1, "%s", out.name);
134 return;
135 }
136
137 /* Don't try to read a really weird amount (like negative). */
138 if (out.offset < 0)
139 errx(1, "%s: illegal offset", "oseek/seek");
140
141 /* If no read access, try using mtio. */
142 if (out.flags & NOREAD) {
143 t_op.mt_op = MTFSR;
144 t_op.mt_count = out.offset;
145
146 if (ioctl(out.fd, MTIOCTOP, &t_op) == -1)
147 err(1, "%s", out.name);
148 return;
149 }
150
151 /* Read it. */
152 for (cnt = 0; cnt < out.offset; ++cnt) {
153 if ((n = read(out.fd, out.db, out.dbsz)) > 0)
154 continue;
155
156 if (n == -1)
157 err(1, "%s", out.name);
158
159 /*
160 * If reach EOF, fill with NUL characters; first, back up over
161 * the EOF mark. Note, cnt has not yet been incremented, so
162 * the EOF read does not count as a seek'd block.
163 */
164 t_op.mt_op = MTBSR;
165 t_op.mt_count = 1;
166 if (ioctl(out.fd, MTIOCTOP, &t_op) == -1)
167 err(1, "%s", out.name);
168
169 while (cnt++ < out.offset) {
170 n = write(out.fd, out.db, out.dbsz);
171 if (n == -1)
172 err(1, "%s", out.name);
173 if ((size_t)n != out.dbsz)
174 errx(1, "%s: write failure", out.name);
175 }
176 break;
177 }
178}