1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
|
/*
* Copyright (c) 1999 by David I. Bell
* Permission is granted to use, distribute, or modify this source,
* provided that this copyright notice remains intact.
*
* The "dd" command, originally taken from sash.
*
* Permission to distribute this code under the GPL has been granted.
* Mostly rewritten and bugs fixed for busybox by Erik Andersen <andersee@debian.org>
*/
#include "internal.h"
#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
const char dd_usage[] =
"Copy a file, converting and formatting according to options\n\
\n\
usage: [if=name] [of=name] [bs=n] [count=n]\n\
\tif=FILE\tread from FILE instead of stdin\n\
\tof=FILE\twrite to FILE instead of stout\n\
\tbs=n\tread and write N BYTES at a time\n\
\tcount=n\tcopy only n input blocks\n\
\tskip=n\tskip n input blocks\n\
\n\
BYTES may be suffixed: by k for x1024, b for x512, and w for x2.\n";
/*
* Read a number with a possible multiplier.
* Returns -1 if the number format is illegal.
*/
static long getNum (const char *cp)
{
long value;
if (!isDecimal (*cp))
return -1;
value = 0;
while (isDecimal (*cp))
value = value * 10 + *cp++ - '0';
switch (*cp++) {
case 'k':
value *= 1024;
break;
case 'b':
value *= 512;
break;
case 'w':
value *= 2;
break;
case '\0':
return value;
default:
return -1;
}
if (*cp)
return -1;
return value;
}
extern int dd_main (int argc, char **argv)
{
const char *inFile;
const char *outFile;
char *cp;
int inFd;
int outFd;
int inCc = 0;
int outCc;
int skipBlocks;
int blockSize;
long count;
long intotal;
long outTotal;
unsigned char *buf;
inFile = NULL;
outFile = NULL;
blockSize = 512;
skipBlocks = 0;
count = 1;
argc--;
argv++;
/* Parse any options */
while (argc) {
if (inFile == NULL && (strncmp(*argv, "if", 2) == 0))
inFile=((strchr(*argv, '='))+1);
else if (outFile == NULL && (strncmp(*argv, "of", 2) == 0))
outFile=((strchr(*argv, '='))+1);
else if (strncmp("count", *argv, 5) == 0) {
count = getNum ((strchr(*argv, '='))+1);
if (count <= 0) {
fprintf (stderr, "Bad count value %ld\n", count);
goto usage;
}
}
else if (strncmp(*argv, "bs", 2) == 0) {
blockSize = getNum ((strchr(*argv, '='))+1);
if (blockSize <= 0) {
fprintf (stderr, "Bad block size value %d\n", blockSize);
goto usage;
}
}
else if (strncmp(*argv, "skip", 4) == 0) {
skipBlocks = atoi( *argv);
if (skipBlocks <= 0) {
fprintf (stderr, "Bad skip value %d\n", skipBlocks);
goto usage;
}
}
else {
fprintf (stderr, "Got here. argv=%s\n", *argv);
goto usage;
}
argc--;
argv++;
}
if ( inFile == NULL || outFile == NULL)
goto usage;
buf = malloc (blockSize);
if (buf == NULL) {
fprintf (stderr, "Cannot allocate buffer\n");
exit( FALSE);
}
intotal = 0;
outTotal = 0;
if (inFile == NULL)
inFd = STDIN;
else
inFd = open (inFile, 0);
if (inFd < 0) {
perror (inFile);
free (buf);
exit( FALSE);
}
if (outFile == NULL)
outFd = STDOUT;
else
outFd = creat (outFile, 0666);
if (outFd < 0) {
perror (outFile);
close (inFd);
free (buf);
exit( FALSE);
}
//lseek(inFd, skipBlocks*blockSize, SEEK_SET);
while (outTotal < count * blockSize) {
inCc = read (inFd, buf, blockSize);
if (inCc < 0) {
perror (inFile);
goto cleanup;
}
intotal += inCc;
cp = buf;
while (intotal > outTotal) {
if (outTotal + inCc > count * blockSize)
inCc = count * blockSize - outTotal;
outCc = write (outFd, cp, inCc);
if (outCc < 0) {
perror (outFile);
goto cleanup;
}
inCc -= outCc;
cp += outCc;
outTotal += outCc;
}
}
if (inCc < 0)
perror (inFile);
cleanup:
close (inFd);
close (outFd);
free (buf);
printf ("%ld+%d records in\n", intotal / blockSize,
(intotal % blockSize) != 0);
printf ("%ld+%d records out\n", outTotal / blockSize,
(outTotal % blockSize) != 0);
exit( TRUE);
usage:
fprintf (stderr, "%s", dd_usage);
exit( FALSE);
}
|
