1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * lib/hexdump.c
4 */
5
6 #include <linux/types.h>
7 #include <linux/ctype.h>
8 #include <linux/errno.h>
9 #include <linux/kernel.h>
10 #include <linux/export.h>
11 #include <asm/unaligned.h>
12
13 const char hex_asc[] = "0123456789abcdef";
14 EXPORT_SYMBOL(hex_asc);
15 const char hex_asc_upper[] = "0123456789ABCDEF";
16 EXPORT_SYMBOL(hex_asc_upper);
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 */
25 int 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 }
34 EXPORT_SYMBOL(hex_to_bin);
35
36 /**
37 * hex2bin - convert an ascii hexadecimal string to its binary representation
38 * @dst: binary result
39 * @src: ascii hexadecimal string
40 * @count: result length
41 *
42 * Return 0 on success, -EINVAL in case of bad input.
43 */
44 int hex2bin(u8 *dst, const char *src, size_t count)
45 {
46 while (count--) {
47 int hi = hex_to_bin(*src++);
48 int lo = hex_to_bin(*src++);
49
50 if ((hi < 0) || (lo < 0))
51 return -EINVAL;
52
53 *dst++ = (hi << 4) | lo;
54 }
55 return 0;
56 }
57 EXPORT_SYMBOL(hex2bin);
58
59 /**
60 * bin2hex - convert binary data to an ascii hexadecimal string
61 * @dst: ascii hexadecimal result
62 * @src: binary data
63 * @count: binary data length
64 */
65 char *bin2hex(char *dst, const void *src, size_t count)
66 {
67 const unsigned char *_src = src;
68
69 while (count--)
70 dst = hex_byte_pack(dst, *_src++);
71 return dst;
72 }
73 EXPORT_SYMBOL(bin2hex);
74
75 /**
76 * hex_dump_to_buffer - convert a blob of data to "hex ASCII" in memory
77 * @buf: data blob to dump
78 * @len: number of bytes in the @buf
79 * @rowsize: number of bytes to print per line; must be 16 or 32
80 * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
81 * @linebuf: where to put the converted data
82 * @linebuflen: total size of @linebuf, including space for terminating NUL
83 * @ascii: include ASCII after the hex output
84 *
85 * hex_dump_to_buffer() works on one "line" of output at a time, i.e.,
86 * 16 or 32 bytes of input data converted to hex + ASCII output.
87 *
88 * Given a buffer of u8 data, hex_dump_to_buffer() converts the input data
89 * to a hex + ASCII dump at the supplied memory location.
90 * The converted output is always NUL-terminated.
91 *
92 * E.g.:
93 * hex_dump_to_buffer(frame->data, frame->len, 16, 1,
94 * linebuf, sizeof(linebuf), true);
95 *
96 * example output buffer:
97 * 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO
98 *
99 * Return:
100 * The amount of bytes placed in the buffer without terminating NUL. If the
101 * output was truncated, then the return value is the number of bytes
102 * (excluding the terminating NUL) which would have been written to the final
103 * string if enough space had been available.
104 */
105 int hex_dump_to_buffer(const void *buf, size_t len, int rowsize, int groupsize,
106 char *linebuf, size_t linebuflen, bool ascii)
107 {
108 const u8 *ptr = buf;
109 int ngroups;
110 u8 ch;
111 int j, lx = 0;
112 int ascii_column;
113 int ret;
114
115 if (rowsize != 16 && rowsize != 32)
116 rowsize = 16;
117
118 if (len > rowsize) /* limit to one line at a time */
119 len = rowsize;
120 if (!is_power_of_2(groupsize) || groupsize > 8)
121 groupsize = 1;
122 if ((len % groupsize) != 0) /* no mixed size output */
123 groupsize = 1;
124
125 ngroups = len / groupsize;
126 ascii_column = rowsize * 2 + rowsize / groupsize + 1;
127
128 if (!linebuflen)
129 goto overflow1;
130
131 if (!len)
132 goto nil;
133
134 if (groupsize == 8) {
135 const u64 *ptr8 = buf;
136
137 for (j = 0; j < ngroups; j++) {
138 ret = snprintf(linebuf + lx, linebuflen - lx,
139 "%s%16.16llx", j ? " " : "",
140 get_unaligned(ptr8 + j));
141 if (ret >= linebuflen - lx)
142 goto overflow1;
143 lx += ret;
144 }
145 } else if (groupsize == 4) {
146 const u32 *ptr4 = buf;
147
148 for (j = 0; j < ngroups; j++) {
149 ret = snprintf(linebuf + lx, linebuflen - lx,
150 "%s%8.8x", j ? " " : "",
151 get_unaligned(ptr4 + j));
152 if (ret >= linebuflen - lx)
153 goto overflow1;
154 lx += ret;
155 }
156 } else if (groupsize == 2) {
157 const u16 *ptr2 = buf;
158
159 for (j = 0; j < ngroups; j++) {
160 ret = snprintf(linebuf + lx, linebuflen - lx,
161 "%s%4.4x", j ? " " : "",
162 get_unaligned(ptr2 + j));
163 if (ret >= linebuflen - lx)
164 goto overflow1;
165 lx += ret;
166 }
167 } else {
168 for (j = 0; j < len; j++) {
169 if (linebuflen < lx + 2)
170 goto overflow2;
171 ch = ptr[j];
172 linebuf[lx++] = hex_asc_hi(ch);
173 if (linebuflen < lx + 2)
174 goto overflow2;
175 linebuf[lx++] = hex_asc_lo(ch);
176 if (linebuflen < lx + 2)
177 goto overflow2;
178 linebuf[lx++] = ' ';
179 }
180 if (j)
181 lx--;
182 }
183 if (!ascii)
184 goto nil;
185
186 while (lx < ascii_column) {
187 if (linebuflen < lx + 2)
188 goto overflow2;
189 linebuf[lx++] = ' ';
190 }
191 for (j = 0; j < len; j++) {
192 if (linebuflen < lx + 2)
193 goto overflow2;
194 ch = ptr[j];
195 linebuf[lx++] = (isascii(ch) && isprint(ch)) ? ch : '.';
196 }
197 nil:
198 linebuf[lx] = '\0';
199 return lx;
200 overflow2:
201 linebuf[lx++] = '\0';
202 overflow1:
203 return ascii ? ascii_column + len : (groupsize * 2 + 1) * ngroups - 1;
204 }
205 EXPORT_SYMBOL(hex_dump_to_buffer);
206
207 #ifdef CONFIG_PRINTK
208 /**
209 * print_hex_dump - print a text hex dump to syslog for a binary blob of data
210 * @level: kernel log level (e.g. KERN_DEBUG)
211 * @prefix_str: string to prefix each line with;
212 * caller supplies trailing spaces for alignment if desired
213 * @prefix_type: controls whether prefix of an offset, address, or none
214 * is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
215 * @rowsize: number of bytes to print per line; must be 16 or 32
216 * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
217 * @buf: data blob to dump
218 * @len: number of bytes in the @buf
219 * @ascii: include ASCII after the hex output
220 *
221 * Given a buffer of u8 data, print_hex_dump() prints a hex + ASCII dump
222 * to the kernel log at the specified kernel log level, with an optional
223 * leading prefix.
224 *
225 * print_hex_dump() works on one "line" of output at a time, i.e.,
226 * 16 or 32 bytes of input data converted to hex + ASCII output.
227 * print_hex_dump() iterates over the entire input @buf, breaking it into
228 * "line size" chunks to format and print.
229 *
230 * E.g.:
231 * print_hex_dump(KERN_DEBUG, "raw data: ", DUMP_PREFIX_ADDRESS,
232 * 16, 1, frame->data, frame->len, true);
233 *
234 * Example output using %DUMP_PREFIX_OFFSET and 1-byte mode:
235 * 0009ab42: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO
236 * Example output using %DUMP_PREFIX_ADDRESS and 4-byte mode:
237 * ffffffff88089af0: 73727170 77767574 7b7a7978 7f7e7d7c pqrstuvwxyz{|}~.
238 */
239 void print_hex_dump(const char *level, const char *prefix_str, int prefix_type,
240 int rowsize, int groupsize,
241 const void *buf, size_t len, bool ascii)
242 {
243 const u8 *ptr = buf;
244 int i, linelen, remaining = len;
245 unsigned char linebuf[32 * 3 + 2 + 32 + 1];
246
247 if (rowsize != 16 && rowsize != 32)
248 rowsize = 16;
249
250 for (i = 0; i < len; i += rowsize) {
251 linelen = min(remaining, rowsize);
252 remaining -= rowsize;
253
254 hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
255 linebuf, sizeof(linebuf), ascii);
256
257 switch (prefix_type) {
258 case DUMP_PREFIX_ADDRESS:
259 printk("%s%s%p: %s\n",
260 level, prefix_str, ptr + i, linebuf);
261 break;
262 case DUMP_PREFIX_OFFSET:
263 printk("%s%s%.8x: %s\n", level, prefix_str, i, linebuf);
264 break;
265 default:
266 printk("%s%s%s\n", level, prefix_str, linebuf);
267 break;
268 }
269 }
270 }
271 EXPORT_SYMBOL(print_hex_dump);
272
273 #endif /* defined(CONFIG_PRINTK) */