1 /* xxd.c - hexdump.
2 *
3 * Copyright 2015 The Android Open Source Project
4 *
5 * No obvious standard.
6 * Regular output:
7 * "00000000: 4c69 6e75 7820 7665 7273 696f 6e20 342e Linux version 4."
8 * xxd -i "include" or "initializer" output:
9 * " 0x4c, 0x69, 0x6e, 0x75, 0x78, 0x20, 0x76, 0x65, 0x72, 0x73, 0x69, 0x6f,"
10 * xxd -p "plain" output:
11 * "4c696e75782076657273696f6e20342e392e302d342d616d643634202864"
12
13 USE_XXD(NEWTOY(xxd, ">1c#<0>256l#o#g#<0=2eiprs#[!rs][!re]", TOYFLAG_USR|TOYFLAG_BIN))
14
15 config XXD
16 bool "xxd"
17 default y
18 help
19 usage: xxd [-eipr] [-cglos N] [file]
20
21 Hexdump a file to stdout. If no file is listed, copy from stdin.
22 Filename "-" is a synonym for stdin.
23
24 -c N Show N bytes per line (default 16)
25 -e Little-endian
26 -g N Group bytes by adding a ' ' every N bytes (default 2)
27 -i Output include file (CSV hex bytes, plus C header/footer if not stdin)
28 -l N Limit of N bytes before stopping (default is no limit)
29 -o N Add N to display offset
30 -p Plain hexdump (30 bytes/line, no grouping. With -c 0 no wrap/group)
31 -r Reverse operation: turn a hexdump into a binary file
32 -s N Skip to offset N
33 */
34
35 #define FOR_xxd
36 #include "toys.h"
37
GLOBALS(long s,g,o,l,c;)38 GLOBALS(
39 long s, g, o, l, c;
40 )
41
42 static void do_xxd(int fd, char *name)
43 {
44 FILE *fp = xfdopen(xdup(fd), "r");
45 long long pos = 0;
46 long long limit = TT.l;
47 int i, j, k, len, space, c = TT.c ? : sizeof(toybuf);
48
49 if (FLAG(s)) {
50 if (fseek(fp, TT.s, SEEK_SET)) perror_exit("seek %ld", TT.s);
51 pos = TT.s;
52 if (limit) limit += TT.s;
53 }
54
55 while ((len=fread(toybuf, 1, (limit && limit-pos<c) ? limit-pos : c, fp))>0){
56 if (!FLAG(p)) printf("%08llx: ", TT.o + pos);
57 pos += len;
58 space = 2*TT.c;
59 space += TT.g ? (TT.c+TT.g-1)/TT.g+1 : 2;
60
61 for (i=0, j=1; i<len; ) {
62 // Insert padding for short groups in little-endian mode.
63 if (FLAG(e) && j==1 && (len-i)<TT.g) {
64 for (k=0; k<(TT.g-(len-i)); k++) {
65 space -= printf(" ");
66 j++;
67 }
68 }
69
70 space -= printf("%02x", toybuf[FLAG(e) ? (i + TT.g - j) : i]);
71 i++,j+=2;
72 if (!FLAG(p) && TT.g && !(i%TT.g)) {
73 putchar(' ');
74 space--;
75 j=1;
76 }
77 }
78
79 if (!FLAG(p)) {
80 printf("%*s", space, "");
81 for (i = 0; i<len; i++)
82 putchar((toybuf[i]>=' ' && toybuf[i]<='~') ? toybuf[i] : '.');
83 }
84 if (TT.c || !FLAG(p)) putchar('\n');
85 }
86 if (!TT.c && FLAG(p)) putchar('\n');
87 if (len<0) perror_exit("read");
88 fclose(fp);
89 }
90
do_xxd_include(int fd,char * name)91 static void do_xxd_include(int fd, char *name)
92 {
93 int c = 1, i, len;
94
95 // The original xxd outputs a header/footer if given a filename (not stdin).
96 // We don't, which means that unlike the original we can implement -ri.
97 while ((len = read(fd, toybuf, sizeof(toybuf))) > 0) {
98 for (i = 0; i < len; ++i) {
99 printf("%s%#.02x", c > 1 ? ", " : " ", toybuf[i]);
100 if (c++ == TT.c) {
101 xprintf(",\n");
102 c = 1;
103 }
104 }
105 }
106 if (len < 0) perror_msg_raw(name);
107 if (c > 1) xputc('\n');
108 }
109
dehex(char ch)110 static int dehex(char ch)
111 {
112 if (ch >= '0' && ch <= '9') return ch - '0';
113 if (ch >= 'a' && ch <= 'f') return ch - 'a' + 10;
114 if (ch >= 'A' && ch <= 'F') return ch - 'A' + 10;
115 return (ch == '\n') ? -2 : -1;
116 }
117
do_xxd_reverse(int fd,char * name)118 static void do_xxd_reverse(int fd, char *name)
119 {
120 FILE *fp = xfdopen(xdup(fd), "r");
121 long long pos, current_pos = 0;
122 int tmp;
123
124 // -ri is a very easy special case.
125 if (FLAG(i)) while (fscanf(fp, " 0x%02x,", &tmp) == 1) xputc(tmp);
126 else while (!feof(fp)) {
127 int col = 0;
128 char ch;
129
130 // Each line of a regular hexdump starts with an offset/address.
131 // Each line of a plain hexdump just goes straight into the bytes.
132 if (!FLAG(p) && fscanf(fp, "%llx%c ", &pos, &ch) == 2) {
133 if (ch != ':' && ch != ' ')
134 error_exit("%s: no separator between offset/address and bytes "
135 "(missing -p?)", name);
136 if (pos != current_pos && fseek(stdout, pos, SEEK_SET)) {
137 // TODO: just write out zeros if non-seekable?
138 perror_exit("%s: seek %llx failed", name, pos);
139 }
140 }
141
142 // A plain hexdump can have as many bytes per line as you like,
143 // but a non-plain hexdump assumes garbage after it's seen the
144 // specified number of bytes.
145 while (FLAG(p) || !TT.c || col < TT.c) {
146 int n1, n2;
147
148 // If we're at EOF or EOL or we read some non-hex...
149 if ((n1 = n2 = dehex(fgetc(fp))) < 0 || (n2 = dehex(fgetc(fp))) < 0) {
150 // If we're at EOL, start on that line.
151 if (n1 == -2 || n2 == -2) continue;
152 // Otherwise, skip to the next line.
153 break;
154 }
155
156 fputc((n1 << 4) | (n2 & 0xf), stdout);
157 col++;
158 current_pos++;
159
160 // Is there any grouping going on? Ignore a single space.
161 tmp = fgetc(fp);
162 if (tmp != ' ') ungetc(tmp, fp);
163 }
164
165 // Skip anything else on this line (such as the ASCII dump).
166 while ((tmp = fgetc(fp)) != EOF && tmp != '\n');
167 }
168
169 if (ferror(fp)) perror_msg_raw(name);
170 fclose(fp);
171 }
172
xxd_main(void)173 void xxd_main(void)
174 {
175 // Plain style is 30 bytes/line, no grouping.
176 if (!FLAG(c)) TT.c = FLAG(p) ? 30 : FLAG(i) ? 12 : 16;
177 if (FLAG(e) && !FLAG(g)) TT.g = 4;
178 if (FLAG(p) && !FLAG(g)) TT.g = TT.c;
179
180 loopfiles(toys.optargs,
181 FLAG(r) ? do_xxd_reverse : (FLAG(i) ? do_xxd_include : do_xxd));
182 }
183