summaryrefslogtreecommitdiff
path: root/coreutils/dd.c
blob: c0df0b75c2525f27b364b52bffc44ca6ced9bc84 (plain)
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
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
/* vi: set sw=4 ts=4: */
/*
 * Mini dd implementation for busybox
 *
 *
 * Copyright (C) 2000,2001  Matt Kraai
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

#include "busybox.h"
#include <signal.h>  /* For FEATURE_DD_SIGNAL_HANDLING */

static const struct suffix_mult dd_suffixes[] = {
	{ "c", 1 },
	{ "w", 2 },
	{ "b", 512 },
	{ "kD", 1000 },
	{ "k", 1024 },
	{ "K", 1024 },	// compat with coreutils dd
	{ "MD", 1000000 },
	{ "M", 1048576 },
	{ "GD", 1000000000 },
	{ "G", 1073741824 },
	{ NULL, 0 }
};

static off_t out_full, out_part, in_full, in_part;

static void dd_output_status(int ATTRIBUTE_UNUSED cur_signal)
{
	fprintf(stderr, "%"OFF_FMT"+%"OFF_FMT" records in\n"
			"%"OFF_FMT"+%"OFF_FMT" records out\n",
			in_full, in_part,
			out_full, out_part);
}

static ssize_t full_write_or_warn(int fd, const void *buf, size_t len,
		const char* filename)
{
	ssize_t n = full_write(fd, buf, len);
	if (n < 0)
		bb_perror_msg("writing '%s'", filename);
	return n;
}

int dd_main(int argc, char **argv)
{
	enum {
		sync_flag    = 1 << 0,
		noerror      = 1 << 1,
		trunc_flag   = 1 << 2,
		twobufs_flag = 1 << 3,
	};
	int flags = trunc_flag;
	size_t oc = 0, ibs = 512, obs = 512;
	ssize_t n, w;
	off_t seek = 0, skip = 0, count = OFF_T_MAX;
	int oflag, ifd, ofd;
	const char *infile = NULL, *outfile = NULL;
	char *ibuf, *obuf;

	if (ENABLE_FEATURE_DD_SIGNAL_HANDLING) {
		struct sigaction sa;

		memset(&sa, 0, sizeof(sa));
		sa.sa_handler = dd_output_status;
		sa.sa_flags = SA_RESTART;
		sigemptyset(&sa.sa_mask);
		sigaction(SIGUSR1, &sa, 0);
	}

	for (n = 1; n < argc; n++) {
		char *arg = argv[n];
		/* Must fit into positive ssize_t */
		if (ENABLE_FEATURE_DD_IBS_OBS && !strncmp("ibs=", arg, 4))
			ibs = xatoul_range_sfx(arg+4, 0, ((size_t)-1L)/2, dd_suffixes);
		else if (ENABLE_FEATURE_DD_IBS_OBS && !strncmp("obs=", arg, 4))
			obs = xatoul_range_sfx(arg+4, 0, ((size_t)-1L)/2, dd_suffixes);
		else if (!strncmp("bs=", arg, 3))
			ibs = obs = xatoul_range_sfx(arg+3, 0, ((size_t)-1L)/2, dd_suffixes);
		// FIXME: make them capable of eating LARGE numbers
		else if (!strncmp("count=", arg, 6))
			count = xatoul_sfx(arg+6, dd_suffixes);
		else if (!strncmp("seek=", arg, 5))
			seek = xatoul_sfx(arg+5, dd_suffixes);
		else if (!strncmp("skip=", arg, 5))
			skip = xatoul_sfx(arg+5, dd_suffixes);

		else if (!strncmp("if=", arg, 3))
			infile = arg+3;
		else if (!strncmp("of=", arg, 3))
			outfile = arg+3;
		else if (ENABLE_FEATURE_DD_IBS_OBS && !strncmp("conv=", arg, 5)) {
			arg += 5;
			while (1) {
				if (!strncmp("notrunc", arg, 7)) {
					flags &= ~trunc_flag;
					arg += 7;
				} else if (!strncmp("sync", arg, 4)) {
					flags |= sync_flag;
					arg += 4;
				} else if (!strncmp("noerror", arg, 7)) {
					flags |= noerror;
					arg += 7;
				} else {
					bb_error_msg_and_die(bb_msg_invalid_arg, arg, "conv");
				}
				if (arg[0] == '\0') break;
				if (*arg++ != ',') bb_show_usage();
			}
		} else
			bb_show_usage();
	}

	ibuf = obuf = xmalloc(ibs);
	if (ibs != obs) {
		flags |= twobufs_flag;
		obuf = xmalloc(obs);
	}

	if (infile != NULL)
		ifd = xopen(infile, O_RDONLY);
	else {
		ifd = STDIN_FILENO;
		infile = bb_msg_standard_input;
	}

	if (outfile != NULL) {
		oflag = O_WRONLY | O_CREAT;

		if (!seek && (flags & trunc_flag))
			oflag |= O_TRUNC;

		ofd = xopen3(outfile, oflag, 0666);

		if (seek && (flags & trunc_flag)) {
			if (ftruncate(ofd, seek * obs) < 0) {
				struct stat st;

				if (fstat(ofd, &st) < 0 || S_ISREG(st.st_mode) ||
						S_ISDIR(st.st_mode))
					goto die_outfile;
			}
		}
	} else {
		ofd = STDOUT_FILENO;
		outfile = bb_msg_standard_output;
	}

	if (skip) {
		if (lseek(ifd, skip * ibs, SEEK_CUR) < 0) {
			while (skip-- > 0) {
				n = safe_read(ifd, ibuf, ibs);
				if (n < 0)
					bb_perror_msg_and_die("%s", infile);
				if (n == 0)
					break;
			}
		}
	}

	if (seek) {
		if (lseek(ofd, seek * obs, SEEK_CUR) < 0)
			goto die_outfile;
	}

	while (in_full + in_part != count) {
		if (flags & noerror) {
			/* Pre-zero the buffer when doing the noerror thing */
			memset(ibuf, '\0', ibs);
		}

		n = safe_read(ifd, ibuf, ibs);
		if (n == 0)
			break;
		if (n < 0) {
			if (flags & noerror) {
				n = ibs;
				bb_perror_msg("%s", infile);
			} else
				bb_perror_msg_and_die("%s", infile);
		}
		if ((size_t)n == ibs)
			in_full++;
		else {
			in_part++;
			if (flags & sync_flag) {
				memset(ibuf + n, '\0', ibs - n);
				n = ibs;
			}
		}
		if (flags & twobufs_flag) {
			char *tmp = ibuf;
			while (n) {
				size_t d = obs - oc;

				if (d > n)
					d = n;
				memcpy(obuf + oc, tmp, d);
				n -= d;
				tmp += d;
				oc += d;
				if (oc == obs) {
					w = full_write_or_warn(ofd, obuf, obs, outfile);
					if (w < 0) goto out_status;
					if (w == obs)
						out_full++;
					else if (w > 0)
						out_part++;
					oc = 0;
				}
			}
		} else {
			w = full_write_or_warn(ofd, ibuf, n, outfile);
			if (w < 0) goto out_status;
			if (w == obs)
				out_full++;
			else if (w > 0)
				out_part++;
		}
	}

	if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
		w = full_write_or_warn(ofd, obuf, oc, outfile);
		if (w < 0) goto out_status;
		if (w > 0)
			out_part++;
	}
	if (close(ifd) < 0) {
		bb_perror_msg_and_die("%s", infile);
	}

	if (close(ofd) < 0) {
 die_outfile:
		bb_perror_msg_and_die("%s", outfile);
	}
 out_status:
	dd_output_status(0);

	return EXIT_SUCCESS;
}