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 long long pos = 0;
45 long long limit = TT.l;
46 int i, j, k, len, space, c = TT.c ? : sizeof(toybuf);
47
48 if (FLAG(s)) {
49 xlseek(fd, TT.s, SEEK_SET);
50 pos = TT.s;
51 if (limit) limit += TT.s;
52 }
53
54 while (0<(len = readall(fd, toybuf,
55 (limit && limit-pos<c)?limit-pos:c)))
56 {
57 if (!FLAG(p)) printf("%08llx: ", TT.o + pos);
58 pos += len;
59 space = 2*TT.c;
60 space += TT.g ? (TT.c+TT.g-1)/TT.g+1 : 2;
61
62 for (i=0, j=1; i<len; ) {
63 // Insert padding for short groups in little-endian mode.
64 if (FLAG(e) && j==1 && (len-i)<TT.g) {
65 for (k=0; k<(TT.g-(len-i)); k++) {
66 space -= printf(" ");
67 j++;
68 }
69 }
70
71 space -= printf("%02x", toybuf[FLAG(e) ? (i + TT.g - j) : i]);
72 i++,j+=2;
73 if (TT.g && !(i%TT.g)) {
74 putchar(' ');
75 space--;
76 j=1;
77 }
78 }
79
80 if (!FLAG(p)) {
81 printf("%*s", space, "");
82 for (i = 0; i<len; i++)
83 putchar((toybuf[i]>=' ' && toybuf[i]<='~') ? toybuf[i] : '.');
84 }
85 if (TT.c || !FLAG(p)) putchar('\n');
86 }
87 if (!TT.c && FLAG(p)) putchar('\n');
88 if (len<0) perror_exit("read");
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
129 // Each line of a regular hexdump starts with an offset/address.
130 // Each line of a plain hexdump just goes straight into the bytes.
131 if (!FLAG(p) && fscanf(fp, "%llx: ", &pos) == 1) {
132 if (pos != current_pos && fseek(stdout, pos, SEEK_SET)) {
133 // TODO: just write out zeros if non-seekable?
134 perror_exit("%s: seek failed", name);
135 }
136 }
137
138 // A plain hexdump can have as many bytes per line as you like,
139 // but a non-plain hexdump assumes garbage after it's seen the
140 // specified number of bytes.
141 while (FLAG(p) || !TT.c || col < TT.c) {
142 int n1, n2;
143
144 // If we're at EOF or EOL or we read some non-hex...
145 if ((n1 = n2 = dehex(fgetc(fp))) < 0 || (n2 = dehex(fgetc(fp))) < 0) {
146 // If we're at EOL, start on that line.
147 if (n1 == -2 || n2 == -2) continue;
148 // Otherwise, skip to the next line.
149 break;
150 }
151
152 fputc((n1 << 4) | (n2 & 0xf), stdout);
153 col++;
154 current_pos++;
155
156 // Is there any grouping going on? Ignore a single space.
157 tmp = fgetc(fp);
158 if (tmp != ' ') ungetc(tmp, fp);
159 }
160
161 // Skip anything else on this line (such as the ASCII dump).
162 while ((tmp = fgetc(fp)) != EOF && tmp != '\n');
163 }
164
165 if (ferror(fp)) perror_msg_raw(name);
166 fclose(fp);
167 }
168
xxd_main(void)169 void xxd_main(void)
170 {
171 // Plain style is 30 bytes/line, no grouping.
172 if (!FLAG(c)) TT.c = FLAG(p) ? 30 : FLAG(i) ? 12 : 16;
173 if (FLAG(e) && !FLAG(g)) TT.g = 4;
174 if (FLAG(p) && !FLAG(g)) TT.g = TT.c;
175
176 loopfiles(toys.optargs,
177 FLAG(r) ? do_xxd_reverse : (FLAG(i) ? do_xxd_include : do_xxd));
178 }
179