Root/lib/hexdump.c

1/*
2 * lib/hexdump.c
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation. See README and COPYING for
7 * more details.
8 */
9
10#include <linux/types.h>
11#include <linux/ctype.h>
12#include <linux/kernel.h>
13#include <linux/export.h>
14
15const char hex_asc[] = "0123456789abcdef";
16EXPORT_SYMBOL(hex_asc);
17const char hex_asc_upper[] = "0123456789ABCDEF";
18EXPORT_SYMBOL(hex_asc_upper);
19
20/**
21 * hex_to_bin - convert a hex digit to its real value
22 * @ch: ascii character represents hex digit
23 *
24 * hex_to_bin() converts one hex digit to its actual value or -1 in case of bad
25 * input.
26 */
27int hex_to_bin(char ch)
28{
29    if ((ch >= '0') && (ch <= '9'))
30        return ch - '0';
31    ch = tolower(ch);
32    if ((ch >= 'a') && (ch <= 'f'))
33        return ch - 'a' + 10;
34    return -1;
35}
36EXPORT_SYMBOL(hex_to_bin);
37
38/**
39 * hex2bin - convert an ascii hexadecimal string to its binary representation
40 * @dst: binary result
41 * @src: ascii hexadecimal string
42 * @count: result length
43 *
44 * Return 0 on success, -1 in case of bad input.
45 */
46int hex2bin(u8 *dst, const char *src, size_t count)
47{
48    while (count--) {
49        int hi = hex_to_bin(*src++);
50        int lo = hex_to_bin(*src++);
51
52        if ((hi < 0) || (lo < 0))
53            return -1;
54
55        *dst++ = (hi << 4) | lo;
56    }
57    return 0;
58}
59EXPORT_SYMBOL(hex2bin);
60
61/**
62 * hex_dump_to_buffer - convert a blob of data to "hex ASCII" in memory
63 * @buf: data blob to dump
64 * @len: number of bytes in the @buf
65 * @rowsize: number of bytes to print per line; must be 16 or 32
66 * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
67 * @linebuf: where to put the converted data
68 * @linebuflen: total size of @linebuf, including space for terminating NUL
69 * @ascii: include ASCII after the hex output
70 *
71 * hex_dump_to_buffer() works on one "line" of output at a time, i.e.,
72 * 16 or 32 bytes of input data converted to hex + ASCII output.
73 *
74 * Given a buffer of u8 data, hex_dump_to_buffer() converts the input data
75 * to a hex + ASCII dump at the supplied memory location.
76 * The converted output is always NUL-terminated.
77 *
78 * E.g.:
79 * hex_dump_to_buffer(frame->data, frame->len, 16, 1,
80 * linebuf, sizeof(linebuf), true);
81 *
82 * example output buffer:
83 * 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO
84 */
85void hex_dump_to_buffer(const void *buf, size_t len, int rowsize,
86            int groupsize, char *linebuf, size_t linebuflen,
87            bool ascii)
88{
89    const u8 *ptr = buf;
90    u8 ch;
91    int j, lx = 0;
92    int ascii_column;
93
94    if (rowsize != 16 && rowsize != 32)
95        rowsize = 16;
96
97    if (!len)
98        goto nil;
99    if (len > rowsize) /* limit to one line at a time */
100        len = rowsize;
101    if ((len % groupsize) != 0) /* no mixed size output */
102        groupsize = 1;
103
104    switch (groupsize) {
105    case 8: {
106        const u64 *ptr8 = buf;
107        int ngroups = len / groupsize;
108
109        for (j = 0; j < ngroups; j++)
110            lx += scnprintf(linebuf + lx, linebuflen - lx,
111                    "%s%16.16llx", j ? " " : "",
112                    (unsigned long long)*(ptr8 + j));
113        ascii_column = 17 * ngroups + 2;
114        break;
115    }
116
117    case 4: {
118        const u32 *ptr4 = buf;
119        int ngroups = len / groupsize;
120
121        for (j = 0; j < ngroups; j++)
122            lx += scnprintf(linebuf + lx, linebuflen - lx,
123                    "%s%8.8x", j ? " " : "", *(ptr4 + j));
124        ascii_column = 9 * ngroups + 2;
125        break;
126    }
127
128    case 2: {
129        const u16 *ptr2 = buf;
130        int ngroups = len / groupsize;
131
132        for (j = 0; j < ngroups; j++)
133            lx += scnprintf(linebuf + lx, linebuflen - lx,
134                    "%s%4.4x", j ? " " : "", *(ptr2 + j));
135        ascii_column = 5 * ngroups + 2;
136        break;
137    }
138
139    default:
140        for (j = 0; (j < len) && (lx + 3) <= linebuflen; j++) {
141            ch = ptr[j];
142            linebuf[lx++] = hex_asc_hi(ch);
143            linebuf[lx++] = hex_asc_lo(ch);
144            linebuf[lx++] = ' ';
145        }
146        if (j)
147            lx--;
148
149        ascii_column = 3 * rowsize + 2;
150        break;
151    }
152    if (!ascii)
153        goto nil;
154
155    while (lx < (linebuflen - 1) && lx < (ascii_column - 1))
156        linebuf[lx++] = ' ';
157    for (j = 0; (j < len) && (lx + 2) < linebuflen; j++) {
158        ch = ptr[j];
159        linebuf[lx++] = (isascii(ch) && isprint(ch)) ? ch : '.';
160    }
161nil:
162    linebuf[lx++] = '\0';
163}
164EXPORT_SYMBOL(hex_dump_to_buffer);
165
166#ifdef CONFIG_PRINTK
167/**
168 * print_hex_dump - print a text hex dump to syslog for a binary blob of data
169 * @level: kernel log level (e.g. KERN_DEBUG)
170 * @prefix_str: string to prefix each line with;
171 * caller supplies trailing spaces for alignment if desired
172 * @prefix_type: controls whether prefix of an offset, address, or none
173 * is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
174 * @rowsize: number of bytes to print per line; must be 16 or 32
175 * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
176 * @buf: data blob to dump
177 * @len: number of bytes in the @buf
178 * @ascii: include ASCII after the hex output
179 *
180 * Given a buffer of u8 data, print_hex_dump() prints a hex + ASCII dump
181 * to the kernel log at the specified kernel log level, with an optional
182 * leading prefix.
183 *
184 * print_hex_dump() works on one "line" of output at a time, i.e.,
185 * 16 or 32 bytes of input data converted to hex + ASCII output.
186 * print_hex_dump() iterates over the entire input @buf, breaking it into
187 * "line size" chunks to format and print.
188 *
189 * E.g.:
190 * print_hex_dump(KERN_DEBUG, "raw data: ", DUMP_PREFIX_ADDRESS,
191 * 16, 1, frame->data, frame->len, true);
192 *
193 * Example output using %DUMP_PREFIX_OFFSET and 1-byte mode:
194 * 0009ab42: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO
195 * Example output using %DUMP_PREFIX_ADDRESS and 4-byte mode:
196 * ffffffff88089af0: 73727170 77767574 7b7a7978 7f7e7d7c pqrstuvwxyz{|}~.
197 */
198void print_hex_dump(const char *level, const char *prefix_str, int prefix_type,
199            int rowsize, int groupsize,
200            const void *buf, size_t len, bool ascii)
201{
202    const u8 *ptr = buf;
203    int i, linelen, remaining = len;
204    unsigned char linebuf[32 * 3 + 2 + 32 + 1];
205
206    if (rowsize != 16 && rowsize != 32)
207        rowsize = 16;
208
209    for (i = 0; i < len; i += rowsize) {
210        linelen = min(remaining, rowsize);
211        remaining -= rowsize;
212
213        hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
214                   linebuf, sizeof(linebuf), ascii);
215
216        switch (prefix_type) {
217        case DUMP_PREFIX_ADDRESS:
218            printk("%s%s%p: %s\n",
219                   level, prefix_str, ptr + i, linebuf);
220            break;
221        case DUMP_PREFIX_OFFSET:
222            printk("%s%s%.8x: %s\n", level, prefix_str, i, linebuf);
223            break;
224        default:
225            printk("%s%s%s\n", level, prefix_str, linebuf);
226            break;
227        }
228    }
229}
230EXPORT_SYMBOL(print_hex_dump);
231
232#if !defined(CONFIG_DYNAMIC_DEBUG)
233/**
234 * print_hex_dump_bytes - shorthand form of print_hex_dump() with default params
235 * @prefix_str: string to prefix each line with;
236 * caller supplies trailing spaces for alignment if desired
237 * @prefix_type: controls whether prefix of an offset, address, or none
238 * is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
239 * @buf: data blob to dump
240 * @len: number of bytes in the @buf
241 *
242 * Calls print_hex_dump(), with log level of KERN_DEBUG,
243 * rowsize of 16, groupsize of 1, and ASCII output included.
244 */
245void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
246              const void *buf, size_t len)
247{
248    print_hex_dump(KERN_DEBUG, prefix_str, prefix_type, 16, 1,
249               buf, len, true);
250}
251EXPORT_SYMBOL(print_hex_dump_bytes);
252#endif /* !defined(CONFIG_DYNAMIC_DEBUG) */
253#endif /* defined(CONFIG_PRINTK) */
254

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