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

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