1 |
|
|
/* $OpenBSD: position.c,v 1.10 2009/10/27 23:59:21 deraadt Exp $ */ |
2 |
|
|
/* $NetBSD: position.c,v 1.4 1995/03/21 09:04:12 cgd Exp $ */ |
3 |
|
|
|
4 |
|
|
/*- |
5 |
|
|
* Copyright (c) 1991, 1993, 1994 |
6 |
|
|
* The Regents of the University of California. All rights reserved. |
7 |
|
|
* |
8 |
|
|
* This code is derived from software contributed to Berkeley by |
9 |
|
|
* Keith Muller of the University of California, San Diego and Lance |
10 |
|
|
* Visser of Convex Computer Corporation. |
11 |
|
|
* |
12 |
|
|
* Redistribution and use in source and binary forms, with or without |
13 |
|
|
* modification, are permitted provided that the following conditions |
14 |
|
|
* are met: |
15 |
|
|
* 1. Redistributions of source code must retain the above copyright |
16 |
|
|
* notice, this list of conditions and the following disclaimer. |
17 |
|
|
* 2. Redistributions in binary form must reproduce the above copyright |
18 |
|
|
* notice, this list of conditions and the following disclaimer in the |
19 |
|
|
* documentation and/or other materials provided with the distribution. |
20 |
|
|
* 3. Neither the name of the University nor the names of its contributors |
21 |
|
|
* may be used to endorse or promote products derived from this software |
22 |
|
|
* without specific prior written permission. |
23 |
|
|
* |
24 |
|
|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
25 |
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
26 |
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
27 |
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
28 |
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
29 |
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
30 |
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
31 |
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
32 |
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
33 |
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
34 |
|
|
* SUCH DAMAGE. |
35 |
|
|
*/ |
36 |
|
|
|
37 |
|
|
#include <sys/types.h> |
38 |
|
|
#include <sys/stat.h> |
39 |
|
|
#include <sys/ioctl.h> |
40 |
|
|
#include <sys/mtio.h> |
41 |
|
|
#include <sys/time.h> |
42 |
|
|
|
43 |
|
|
#include <err.h> |
44 |
|
|
#include <errno.h> |
45 |
|
|
#include <string.h> |
46 |
|
|
#include <unistd.h> |
47 |
|
|
|
48 |
|
|
#include "dd.h" |
49 |
|
|
#include "extern.h" |
50 |
|
|
|
51 |
|
|
/* |
52 |
|
|
* Position input/output data streams before starting the copy. Device type |
53 |
|
|
* dependent. Seekable devices use lseek, and the rest position by reading. |
54 |
|
|
* Seeking past the end of file can cause null blocks to be written to the |
55 |
|
|
* output. |
56 |
|
|
*/ |
57 |
|
|
void |
58 |
|
|
pos_in(void) |
59 |
|
|
{ |
60 |
|
|
size_t bcnt; |
61 |
|
|
ssize_t nr; |
62 |
|
|
off_t cnt; |
63 |
|
|
int warned; |
64 |
|
|
|
65 |
|
|
/* If not a pipe, tape or tty device, try to seek on it. */ |
66 |
|
|
if (!(in.flags & (ISPIPE|ISTAPE)) && !isatty(in.fd)) { |
67 |
|
|
if (lseek(in.fd, in.offset * in.dbsz, SEEK_CUR) == -1) |
68 |
|
|
err(1, "%s", in.name); |
69 |
|
|
return; |
70 |
|
|
} |
71 |
|
|
|
72 |
|
|
/* |
73 |
|
|
* Read the data. If a pipe, read until satisfy the number of bytes |
74 |
|
|
* being skipped. No differentiation for reading complete and partial |
75 |
|
|
* blocks for other devices. |
76 |
|
|
*/ |
77 |
|
|
for (bcnt = in.dbsz, cnt = in.offset, warned = 0; cnt;) { |
78 |
|
|
if ((nr = read(in.fd, in.db, bcnt)) > 0) { |
79 |
|
|
if (in.flags & ISPIPE) { |
80 |
|
|
if (!(bcnt -= nr)) { |
81 |
|
|
bcnt = in.dbsz; |
82 |
|
|
--cnt; |
83 |
|
|
} |
84 |
|
|
} else |
85 |
|
|
--cnt; |
86 |
|
|
continue; |
87 |
|
|
} |
88 |
|
|
|
89 |
|
|
if (nr == 0) { |
90 |
|
|
if (files_cnt > 1) { |
91 |
|
|
--files_cnt; |
92 |
|
|
continue; |
93 |
|
|
} |
94 |
|
|
errx(1, "skip reached end of input"); |
95 |
|
|
} |
96 |
|
|
|
97 |
|
|
/* |
98 |
|
|
* Input error -- either EOF with no more files, or I/O error. |
99 |
|
|
* If noerror not set die. POSIX requires that the warning |
100 |
|
|
* message be followed by an I/O display. |
101 |
|
|
*/ |
102 |
|
|
if (ddflags & C_NOERROR) { |
103 |
|
|
if (!warned) { |
104 |
|
|
warn("%s", in.name); |
105 |
|
|
warned = 1; |
106 |
|
|
summary(); |
107 |
|
|
} |
108 |
|
|
continue; |
109 |
|
|
} |
110 |
|
|
err(1, "%s", in.name); |
111 |
|
|
} |
112 |
|
|
} |
113 |
|
|
|
114 |
|
|
void |
115 |
|
|
pos_out(void) |
116 |
|
|
{ |
117 |
|
|
struct mtop t_op; |
118 |
|
|
off_t cnt; |
119 |
|
|
ssize_t n; |
120 |
|
|
|
121 |
|
|
/* |
122 |
|
|
* If not a tape, try seeking on the file. Seeking on a pipe is |
123 |
|
|
* going to fail, but don't protect the user -- they shouldn't |
124 |
|
|
* have specified the seek operand. |
125 |
|
|
*/ |
126 |
|
|
if (!(out.flags & ISTAPE)) { |
127 |
|
|
if (lseek(out.fd, out.offset * out.dbsz, SEEK_SET) == -1) |
128 |
|
|
err(1, "%s", out.name); |
129 |
|
|
return; |
130 |
|
|
} |
131 |
|
|
|
132 |
|
|
/* If no read access, try using mtio. */ |
133 |
|
|
if (out.flags & NOREAD) { |
134 |
|
|
t_op.mt_op = MTFSR; |
135 |
|
|
t_op.mt_count = out.offset; |
136 |
|
|
|
137 |
|
|
if (ioctl(out.fd, MTIOCTOP, &t_op) < 0) |
138 |
|
|
err(1, "%s", out.name); |
139 |
|
|
return; |
140 |
|
|
} |
141 |
|
|
|
142 |
|
|
/* Read it. */ |
143 |
|
|
for (cnt = 0; cnt < out.offset; ++cnt) { |
144 |
|
|
if ((n = read(out.fd, out.db, out.dbsz)) > 0) |
145 |
|
|
continue; |
146 |
|
|
|
147 |
|
|
if (n < 0) |
148 |
|
|
err(1, "%s", out.name); |
149 |
|
|
|
150 |
|
|
/* |
151 |
|
|
* If reach EOF, fill with NUL characters; first, back up over |
152 |
|
|
* the EOF mark. Note, cnt has not yet been incremented, so |
153 |
|
|
* the EOF read does not count as a seek'd block. |
154 |
|
|
*/ |
155 |
|
|
t_op.mt_op = MTBSR; |
156 |
|
|
t_op.mt_count = 1; |
157 |
|
|
if (ioctl(out.fd, MTIOCTOP, &t_op) == -1) |
158 |
|
|
err(1, "%s", out.name); |
159 |
|
|
|
160 |
|
|
while (cnt++ < out.offset) |
161 |
|
|
if ((n = write(out.fd, out.db, out.dbsz)) != out.dbsz) |
162 |
|
|
err(1, "%s", out.name); |
163 |
|
|
break; |
164 |
|
|
} |
165 |
|
|
} |