1 /* dd.c - program to convert and copy a file.
2 *
3 * Copyright 2013 Ashwini Kumar <ak.ashwini@gmail.com>
4 * Copyright 2013 Kyungwan Han <asura321@gmail.com>
5 *
6 * See http://opengroup.org/onlinepubs/9699919799/utilities/dd.html
7
8 USE_DD(NEWTOY(dd, 0, TOYFLAG_USR|TOYFLAG_BIN))
9
10 config DD
11 bool "dd"
12 default n
13 help
14 usage: dd [if=FILE] [of=FILE] [ibs=N] [obs=N] [iflag=FLAGS] [oflag=FLAGS]
15 [bs=N] [count=N] [seek=N] [skip=N]
16 [conv=notrunc|noerror|sync|fsync] [status=noxfer|none]
17
18 Copy/convert files.
19
20 if=FILE Read from FILE instead of stdin
21 of=FILE Write to FILE instead of stdout
22 bs=N Read and write N bytes at a time
23 ibs=N Input block size
24 obs=N Output block size
25 count=N Copy only N input blocks
26 skip=N Skip N input blocks
27 seek=N Skip N output blocks
28 iflag=FLAGS Set input flags
29 oflag=FLAGS Set output flags
30 conv=notrunc Don't truncate output file
31 conv=noerror Continue after read errors
32 conv=sync Pad blocks with zeros
33 conv=fsync Physically write data out before finishing
34 status=noxfer Don't show transfer rate
35 status=none Don't show transfer rate or records in/out
36
37 FLAGS is a comma-separated list of:
38
39 count_bytes (iflag) interpret count=N in bytes, not blocks
40 seek_bytes (oflag) interpret seek=N in bytes, not blocks
41 skip_bytes (iflag) interpret skip=N in bytes, not blocks
42
43 Numbers may be suffixed by c (*1), w (*2), b (*512), kD (*1000), k (*1024),
44 MD (*1000*1000), M (*1024*1024), GD (*1000*1000*1000) or G (*1024*1024*1024).
45 */
46
47 #define FOR_dd
48 #include "toys.h"
49
50 GLOBALS(
51 int show_xfer, show_records;
52 unsigned long long bytes, c_count, in_full, in_part, out_full, out_part;
53 struct timeval start;
54 struct {
55 char *name;
56 int fd;
57 unsigned char *buff, *bp;
58 long sz, count;
59 unsigned long long offset;
60 } in, out;
61 unsigned conv, iflag, oflag;
62 )
63
64 struct dd_flag {
65 char *name;
66 };
67
68 static const struct dd_flag dd_conv[] = TAGGED_ARRAY(DD_conv,
69 {"fsync"}, {"noerror"}, {"notrunc"}, {"sync"},
70 );
71
72 static const struct dd_flag dd_iflag[] = TAGGED_ARRAY(DD_iflag,
73 {"count_bytes"}, {"skip_bytes"},
74 );
75
76 static const struct dd_flag dd_oflag[] = TAGGED_ARRAY(DD_oflag,
77 {"seek_bytes"},
78 );
79
status()80 static void status()
81 {
82 double seconds;
83 struct timeval now;
84
85 gettimeofday(&now, NULL);
86 seconds = ((now.tv_sec * 1000000 + now.tv_usec) -
87 (TT.start.tv_sec * 1000000 + TT.start.tv_usec))/1000000.0;
88
89 if (TT.show_records)
90 fprintf(stderr, "%llu+%llu records in\n%llu+%llu records out\n",
91 TT.in_full, TT.in_part, TT.out_full, TT.out_part);
92
93 if (TT.show_xfer) {
94 human_readable(toybuf, TT.bytes, HR_SPACE|HR_B);
95 fprintf(stderr, "%llu bytes (%s) copied, ", TT.bytes, toybuf);
96 human_readable(toybuf, TT.bytes/seconds, HR_SPACE|HR_B);
97 fprintf(stderr, "%f s, %s/s\n", seconds, toybuf);
98 }
99 }
100
dd_sigint(int sig)101 static void dd_sigint(int sig)
102 {
103 toys.exitval = sig|128;
104 xexit();
105 }
106
write_out(int all)107 static void write_out(int all)
108 {
109 TT.out.bp = TT.out.buff;
110 while (TT.out.count) {
111 ssize_t nw = writeall(TT.out.fd, TT.out.bp, ((all)? TT.out.count : TT.out.sz));
112
113 all = 0; //further writes will be on obs
114 if (nw <= 0) perror_exit("%s: write error", TT.out.name);
115 if (nw == TT.out.sz) TT.out_full++;
116 else TT.out_part++;
117 TT.out.count -= nw;
118 TT.out.bp += nw;
119 TT.bytes += nw;
120 if (TT.out.count < TT.out.sz) break;
121 }
122 if (TT.out.count) memmove(TT.out.buff, TT.out.bp, TT.out.count); //move remainder to front
123 }
124
parse_flags(char * what,char * arg,const struct dd_flag * flags,int flag_count,unsigned * result)125 static void parse_flags(char *what, char *arg,
126 const struct dd_flag* flags, int flag_count, unsigned *result)
127 {
128 char *pre = xstrdup(arg);
129 int i;
130
131 for (i=0; i<flag_count; ++i) {
132 while (comma_remove(pre, flags[i].name)) *result |= 1<<i;
133 }
134 if (*pre) error_exit("bad %s=%s", what, pre);
135 free(pre);
136 }
137
dd_main()138 void dd_main()
139 {
140 char **args;
141 unsigned long long bs = 0;
142 int trunc = O_TRUNC;
143
144 TT.show_xfer = TT.show_records = 1;
145 TT.c_count = ULLONG_MAX;
146
147 TT.in.sz = TT.out.sz = 512; //default io block size
148 for (args = toys.optargs; *args; args++) {
149 char *arg = *args;
150
151 if (strstart(&arg, "bs=")) bs = atolx_range(arg, 1, LONG_MAX);
152 else if (strstart(&arg, "ibs=")) TT.in.sz = atolx_range(arg, 1, LONG_MAX);
153 else if (strstart(&arg, "obs=")) TT.out.sz = atolx_range(arg, 1, LONG_MAX);
154 else if (strstart(&arg, "count="))
155 TT.c_count = atolx_range(arg, 0, LLONG_MAX);
156 else if (strstart(&arg, "if=")) TT.in.name = arg;
157 else if (strstart(&arg, "of=")) TT.out.name = arg;
158 else if (strstart(&arg, "seek="))
159 TT.out.offset = atolx_range(arg, 0, LLONG_MAX);
160 else if (strstart(&arg, "skip="))
161 TT.in.offset = atolx_range(arg, 0, LLONG_MAX);
162 else if (strstart(&arg, "status=")) {
163 if (!strcmp(arg, "noxfer")) TT.show_xfer = 0;
164 else if (!strcmp(arg, "none")) TT.show_xfer = TT.show_records = 0;
165 else error_exit("unknown status '%s'", arg);
166 } else if (strstart(&arg, "conv=")) {
167 parse_flags("conv", arg, dd_conv, ARRAY_LEN(dd_conv), &TT.conv);
168 fprintf(stderr, "conv=%x\n", TT.conv);
169 } else if (strstart(&arg, "iflag="))
170 parse_flags("iflag", arg, dd_iflag, ARRAY_LEN(dd_iflag), &TT.iflag);
171 else if (strstart(&arg, "oflag="))
172 parse_flags("oflag", arg, dd_oflag, ARRAY_LEN(dd_oflag), &TT.oflag);
173 else error_exit("bad arg %s", arg);
174 }
175 if (bs) TT.in.sz = TT.out.sz = bs;
176
177 sigatexit(status);
178 xsignal(SIGINT, dd_sigint);
179 xsignal(SIGUSR1, status);
180 gettimeofday(&TT.start, NULL);
181
182 // For bs=, in/out is done as it is. so only in.sz is enough.
183 // With Single buffer there will be overflow in a read following partial read.
184 TT.in.buff = TT.out.buff = xmalloc(TT.in.sz + (bs ? 0 : TT.out.sz));
185 TT.in.bp = TT.out.bp = TT.in.buff;
186
187 if (!TT.in.name) TT.in.name = "stdin";
188 else TT.in.fd = xopenro(TT.in.name);
189
190 if (TT.conv & _DD_conv_notrunc) trunc = 0;
191
192 if (!TT.out.name) {
193 TT.out.name = "stdout";
194 TT.out.fd = 1;
195 } else TT.out.fd = xcreate(TT.out.name,
196 O_WRONLY|O_CREAT|(trunc*!TT.out.offset), 0666);
197
198 // Implement skip=
199 if (TT.in.offset) {
200 off_t off = TT.in.offset;
201
202 if (!(TT.iflag & _DD_iflag_skip_bytes)) off *= TT.in.sz;
203 if (lseek(TT.in.fd, off, SEEK_CUR) < 0) {
204 while (off > 0) {
205 int chunk = off < TT.in.sz ? off : TT.in.sz;
206 ssize_t n = read(TT.in.fd, TT.in.bp, chunk);
207
208 if (n < 0) {
209 perror_msg("%s", TT.in.name);
210 if (TT.conv & _DD_conv_noerror) status();
211 else return;
212 } else if (!n) {
213 xprintf("%s: Can't skip\n", TT.in.name);
214 return;
215 }
216 off -= n;
217 }
218 }
219 }
220
221 // Implement seek= and truncate as necessary. We handled position zero
222 // truncate with O_TRUNC on open, so output to /dev/null and such doesn't
223 // error.
224 bs = TT.out.offset;
225 if (!(TT.oflag & _DD_oflag_seek_bytes)) bs *= TT.out.sz;
226 if (bs) {
227 struct stat st;
228
229 xlseek(TT.out.fd, bs, SEEK_CUR);
230 if (trunc && !fstat(TT.out.fd, &st) && S_ISREG(st.st_mode)
231 && ftruncate(TT.out.fd, bs)) perror_exit("unexpected ftruncate failure");
232 }
233
234 unsigned long long bytes_left = TT.c_count;
235 if (TT.c_count != ULLONG_MAX && !(TT.iflag & _DD_iflag_count_bytes)) {
236 bytes_left *= TT.in.sz;
237 }
238 while (bytes_left) {
239 int chunk = bytes_left < TT.in.sz ? bytes_left : TT.in.sz;
240 ssize_t n;
241
242 TT.in.bp = TT.in.buff + TT.in.count;
243 if (TT.conv & _DD_conv_sync) memset(TT.in.bp, 0, TT.in.sz);
244 if (!(n = read(TT.in.fd, TT.in.bp, chunk))) break;
245 if (n < 0) {
246 if (errno == EINTR) continue;
247 //read error case.
248 perror_msg("%s: read error", TT.in.name);
249 if (!(TT.conv & _DD_conv_noerror)) exit(1);
250 status();
251 xlseek(TT.in.fd, TT.in.sz, SEEK_CUR);
252 if (!(TT.conv & _DD_conv_sync)) continue;
253 // if SYNC, then treat as full block of nuls
254 n = TT.in.sz;
255 }
256 if (n == TT.in.sz) {
257 TT.in_full++;
258 TT.in.count += n;
259 } else {
260 TT.in_part++;
261 if (TT.conv & _DD_conv_sync) TT.in.count += TT.in.sz;
262 else TT.in.count += n;
263 }
264 bytes_left -= n;
265
266 TT.out.count = TT.in.count;
267 if (bs) {
268 write_out(1);
269 TT.in.count = 0;
270 continue;
271 }
272
273 if (TT.in.count >= TT.out.sz) {
274 write_out(0);
275 TT.in.count = TT.out.count;
276 }
277 }
278 if (TT.out.count) write_out(1); //write any remaining input blocks
279 if ((TT.conv & _DD_conv_fsync) && fsync(TT.out.fd)<0)
280 perror_exit("%s: fsync", TT.out.name);
281
282 close(TT.in.fd);
283 close(TT.out.fd);
284 if (TT.in.buff) free(TT.in.buff);
285 }
286