Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0-only
2 : /*
3 : * lib/hexdump.c
4 : */
5 :
6 : #include <stdio.h>
7 :
8 : #include "linux_types.h"
9 : #include "defs.h"
10 :
11 : #define __get_unaligned_t(type, ptr) ({ \
12 : const struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr); \
13 : __pptr->x; \
14 : })
15 :
16 : #define get_unaligned(ptr) __get_unaligned_t(typeof(*(ptr)), (ptr))
17 :
18 : const char hex_asc[] = "0123456789abcdef";
19 :
20 : #define hex_asc_lo(x) hex_asc[((x) & 0x0f)]
21 : #define hex_asc_hi(x) hex_asc[((x) & 0xf0) >> 4]
22 :
23 : void print_hex_dump(const char *prefix_str, int prefix_type,
24 : int rowsize, int groupsize,
25 : const void *buf, size_t len, bool ascii);
26 : /**
27 : * hex_dump_to_buffer - convert a blob of data to "hex ASCII" in memory
28 : * @buf: data blob to dump
29 : * @len: number of bytes in the @buf
30 : * @rowsize: number of bytes to print per line; must be 16 or 32
31 : * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
32 : * @linebuf: where to put the converted data
33 : * @linebuflen: total size of @linebuf, including space for terminating NUL
34 : * @ascii: include ASCII after the hex output
35 : *
36 : * hex_dump_to_buffer() works on one "line" of output at a time, i.e.,
37 : * 16 or 32 bytes of input data converted to hex + ASCII output.
38 : *
39 : * Given a buffer of u8 data, hex_dump_to_buffer() converts the input data
40 : * to a hex + ASCII dump at the supplied memory location.
41 : * The converted output is always NUL-terminated.
42 : *
43 : * E.g.:
44 : * hex_dump_to_buffer(frame->data, frame->len, 16, 1,
45 : * linebuf, sizeof(linebuf), true);
46 : *
47 : * example output buffer:
48 : * 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO
49 : *
50 : * Return:
51 : * The amount of bytes placed in the buffer without terminating NUL. If the
52 : * output was truncated, then the return value is the number of bytes
53 : * (excluding the terminating NUL) which would have been written to the final
54 : * string if enough space had been available.
55 : */
56 829680 : static int hex_dump_to_buffer(const void *buf, size_t len, int rowsize,
57 : int groupsize, char *linebuf, size_t linebuflen,
58 : bool ascii)
59 : {
60 829680 : const u8 *ptr = buf;
61 : int ngroups;
62 : u8 ch;
63 829680 : int j, lx = 0;
64 : int ascii_column;
65 : int ret;
66 :
67 829680 : if (rowsize != 16 && rowsize != 32)
68 0 : rowsize = 16;
69 :
70 829680 : if (len > rowsize) /* limit to one line at a time */
71 0 : len = rowsize;
72 1659360 : if (!is_power_of_2(groupsize) || groupsize > 8)
73 0 : groupsize = 1;
74 829680 : if ((len % groupsize) != 0) /* no mixed size output */
75 0 : groupsize = 1;
76 :
77 829680 : ngroups = len / groupsize;
78 829680 : ascii_column = rowsize * 2 + rowsize / groupsize + 1;
79 :
80 829680 : if (!linebuflen)
81 : goto overflow1;
82 :
83 829680 : if (!len)
84 : goto nil;
85 :
86 829680 : if (groupsize == 8) {
87 : const u64 *ptr8 = buf;
88 :
89 0 : for (j = 0; j < ngroups; j++) {
90 0 : ret = snprintf(linebuf + lx, linebuflen - lx,
91 : "%s%16.16llx", j ? " " : "",
92 0 : get_unaligned(ptr8 + j));
93 0 : if (ret >= linebuflen - lx)
94 : goto overflow1;
95 0 : lx += ret;
96 : }
97 829680 : } else if (groupsize == 4) {
98 : const u32 *ptr4 = buf;
99 :
100 5136524 : for (j = 0; j < ngroups; j++) {
101 5136524 : ret = snprintf(linebuf + lx, linebuflen - lx,
102 : "%s%8.8x", j ? " " : "",
103 5136524 : get_unaligned(ptr4 + j));
104 5136524 : if (ret >= linebuflen - lx)
105 : goto overflow1;
106 5136524 : lx += ret;
107 : }
108 187430 : } else if (groupsize == 2) {
109 : const u16 *ptr2 = buf;
110 :
111 0 : for (j = 0; j < ngroups; j++) {
112 0 : ret = snprintf(linebuf + lx, linebuflen - lx,
113 : "%s%4.4x", j ? " " : "",
114 0 : get_unaligned(ptr2 + j));
115 0 : if (ret >= linebuflen - lx)
116 : goto overflow1;
117 0 : lx += ret;
118 : }
119 : } else {
120 4513992 : for (j = 0; j < len; j++) {
121 4513992 : if (linebuflen < lx + 2)
122 : goto overflow2;
123 4513992 : ch = ptr[j];
124 4513992 : linebuf[lx++] = hex_asc_hi(ch);
125 4513992 : if (linebuflen < lx + 2)
126 : goto overflow2;
127 4513992 : linebuf[lx++] = hex_asc_lo(ch);
128 4513992 : if (linebuflen < lx + 2)
129 : goto overflow2;
130 4513992 : linebuf[lx++] = ' ';
131 : }
132 187430 : if (j)
133 187430 : lx--;
134 : }
135 829680 : if (!ascii)
136 : goto nil;
137 :
138 6939840 : while (lx < ascii_column) {
139 6112412 : if (linebuflen < lx + 2)
140 : goto overflow2;
141 6112412 : linebuf[lx++] = ' ';
142 : }
143 24990368 : for (j = 0; j < len; j++) {
144 24990368 : if (linebuflen < lx + 2)
145 : goto overflow2;
146 24990368 : ch = ptr[j];
147 24990368 : linebuf[lx++] = (isascii(ch) && isprint(ch)) ? ch : '.';
148 : }
149 829680 : nil:
150 829680 : linebuf[lx] = '\0';
151 829680 : return lx;
152 0 : overflow2:
153 0 : linebuf[lx++] = '\0';
154 0 : overflow1:
155 0 : return ascii ? ascii_column + len : (groupsize * 2 + 1) * ngroups - 1;
156 : }
157 :
158 : /**
159 : * print_hex_dump - print a text hex dump to syslog for a binary blob of data
160 : * @prefix_str: string to prefix each line with;
161 : * caller supplies trailing spaces for alignment if desired
162 : * @prefix_type: controls whether prefix of an offset, address, or none
163 : * is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
164 : * @rowsize: number of bytes to print per line; must be 16 or 32
165 : * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
166 : * @buf: data blob to dump
167 : * @len: number of bytes in the @buf
168 : * @ascii: include ASCII after the hex output
169 : *
170 : * Given a buffer of u8 data, print_hex_dump() prints a hex + ASCII dump
171 : * to the kernel log at the specified kernel log level, with an optional
172 : * leading prefix.
173 : *
174 : * print_hex_dump() works on one "line" of output at a time, i.e.,
175 : * 16 or 32 bytes of input data converted to hex + ASCII output.
176 : * print_hex_dump() iterates over the entire input @buf, breaking it into
177 : * "line size" chunks to format and print.
178 : *
179 : * E.g.:
180 : * print_hex_dump(KERN_DEBUG, "raw data: ", DUMP_PREFIX_ADDRESS,
181 : * 16, 1, frame->data, frame->len, true);
182 : *
183 : * Example output using %DUMP_PREFIX_OFFSET and 1-byte mode:
184 : * 0009ab42: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO
185 : * Example output using %DUMP_PREFIX_ADDRESS and 4-byte mode:
186 : * ffffffff88089af0: 73727170 77767574 7b7a7978 7f7e7d7c pqrstuvwxyz{|}~.
187 : */
188 188162 : void print_hex_dump(const char *prefix_str, int prefix_type,
189 : int rowsize, int groupsize,
190 : const void *buf, size_t len, bool ascii)
191 : {
192 188162 : const u8 *ptr = buf;
193 188162 : int i, linelen, remaining = len;
194 : char linebuf[32 * 3 + 2 + 32 + 1];
195 :
196 188162 : if (rowsize != 16 && rowsize != 32)
197 0 : rowsize = 16;
198 :
199 1017842 : for (i = 0; i < len; i += rowsize) {
200 829680 : linelen = min(remaining, rowsize);
201 829680 : remaining -= rowsize;
202 :
203 829680 : hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
204 : linebuf, sizeof(linebuf), ascii);
205 :
206 829680 : switch (prefix_type) {
207 0 : case DUMP_PREFIX_ADDRESS:
208 0 : printf("%s%p: %s\n", prefix_str, ptr + i, linebuf);
209 0 : break;
210 829680 : case DUMP_PREFIX_OFFSET:
211 829680 : printf("%s%.8x: %s\n", prefix_str, i, linebuf);
212 829680 : break;
213 0 : default:
214 0 : printf("%s%s\n", prefix_str, linebuf);
215 0 : break;
216 : }
217 : }
218 188162 : }
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