xref: /openbmc/linux/lib/hexdump.c (revision 9d56dd3b083a3bec56e9da35ce07baca81030b03)
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 
15 const char hex_asc[] = "0123456789abcdef";
16 EXPORT_SYMBOL(hex_asc);
17 
18 /**
19  * hex_dump_to_buffer - convert a blob of data to "hex ASCII" in memory
20  * @buf: data blob to dump
21  * @len: number of bytes in the @buf
22  * @rowsize: number of bytes to print per line; must be 16 or 32
23  * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
24  * @linebuf: where to put the converted data
25  * @linebuflen: total size of @linebuf, including space for terminating NUL
26  * @ascii: include ASCII after the hex output
27  *
28  * hex_dump_to_buffer() works on one "line" of output at a time, i.e.,
29  * 16 or 32 bytes of input data converted to hex + ASCII output.
30  *
31  * Given a buffer of u8 data, hex_dump_to_buffer() converts the input data
32  * to a hex + ASCII dump at the supplied memory location.
33  * The converted output is always NUL-terminated.
34  *
35  * E.g.:
36  *   hex_dump_to_buffer(frame->data, frame->len, 16, 1,
37  *			linebuf, sizeof(linebuf), 1);
38  *
39  * example output buffer:
40  * 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f  @ABCDEFGHIJKLMNO
41  */
42 void hex_dump_to_buffer(const void *buf, size_t len, int rowsize,
43 			int groupsize, char *linebuf, size_t linebuflen,
44 			bool ascii)
45 {
46 	const u8 *ptr = buf;
47 	u8 ch;
48 	int j, lx = 0;
49 	int ascii_column;
50 
51 	if (rowsize != 16 && rowsize != 32)
52 		rowsize = 16;
53 
54 	if (!len)
55 		goto nil;
56 	if (len > rowsize)		/* limit to one line at a time */
57 		len = rowsize;
58 	if ((len % groupsize) != 0)	/* no mixed size output */
59 		groupsize = 1;
60 
61 	switch (groupsize) {
62 	case 8: {
63 		const u64 *ptr8 = buf;
64 		int ngroups = len / groupsize;
65 
66 		for (j = 0; j < ngroups; j++)
67 			lx += scnprintf(linebuf + lx, linebuflen - lx,
68 				"%s%16.16llx", j ? " " : "",
69 				(unsigned long long)*(ptr8 + j));
70 		ascii_column = 17 * ngroups + 2;
71 		break;
72 	}
73 
74 	case 4: {
75 		const u32 *ptr4 = buf;
76 		int ngroups = len / groupsize;
77 
78 		for (j = 0; j < ngroups; j++)
79 			lx += scnprintf(linebuf + lx, linebuflen - lx,
80 				"%s%8.8x", j ? " " : "", *(ptr4 + j));
81 		ascii_column = 9 * ngroups + 2;
82 		break;
83 	}
84 
85 	case 2: {
86 		const u16 *ptr2 = buf;
87 		int ngroups = len / groupsize;
88 
89 		for (j = 0; j < ngroups; j++)
90 			lx += scnprintf(linebuf + lx, linebuflen - lx,
91 				"%s%4.4x", j ? " " : "", *(ptr2 + j));
92 		ascii_column = 5 * ngroups + 2;
93 		break;
94 	}
95 
96 	default:
97 		for (j = 0; (j < len) && (lx + 3) <= linebuflen; j++) {
98 			ch = ptr[j];
99 			linebuf[lx++] = hex_asc_hi(ch);
100 			linebuf[lx++] = hex_asc_lo(ch);
101 			linebuf[lx++] = ' ';
102 		}
103 		if (j)
104 			lx--;
105 
106 		ascii_column = 3 * rowsize + 2;
107 		break;
108 	}
109 	if (!ascii)
110 		goto nil;
111 
112 	while (lx < (linebuflen - 1) && lx < (ascii_column - 1))
113 		linebuf[lx++] = ' ';
114 	for (j = 0; (j < len) && (lx + 2) < linebuflen; j++)
115 		linebuf[lx++] = (isascii(ptr[j]) && isprint(ptr[j])) ? ptr[j]
116 				: '.';
117 nil:
118 	linebuf[lx++] = '\0';
119 }
120 EXPORT_SYMBOL(hex_dump_to_buffer);
121 
122 /**
123  * print_hex_dump - print a text hex dump to syslog for a binary blob of data
124  * @level: kernel log level (e.g. KERN_DEBUG)
125  * @prefix_str: string to prefix each line with;
126  *  caller supplies trailing spaces for alignment if desired
127  * @prefix_type: controls whether prefix of an offset, address, or none
128  *  is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
129  * @rowsize: number of bytes to print per line; must be 16 or 32
130  * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
131  * @buf: data blob to dump
132  * @len: number of bytes in the @buf
133  * @ascii: include ASCII after the hex output
134  *
135  * Given a buffer of u8 data, print_hex_dump() prints a hex + ASCII dump
136  * to the kernel log at the specified kernel log level, with an optional
137  * leading prefix.
138  *
139  * print_hex_dump() works on one "line" of output at a time, i.e.,
140  * 16 or 32 bytes of input data converted to hex + ASCII output.
141  * print_hex_dump() iterates over the entire input @buf, breaking it into
142  * "line size" chunks to format and print.
143  *
144  * E.g.:
145  *   print_hex_dump(KERN_DEBUG, "raw data: ", DUMP_PREFIX_ADDRESS,
146  *		16, 1, frame->data, frame->len, 1);
147  *
148  * Example output using %DUMP_PREFIX_OFFSET and 1-byte mode:
149  * 0009ab42: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f  @ABCDEFGHIJKLMNO
150  * Example output using %DUMP_PREFIX_ADDRESS and 4-byte mode:
151  * ffffffff88089af0: 73727170 77767574 7b7a7978 7f7e7d7c  pqrstuvwxyz{|}~.
152  */
153 void print_hex_dump(const char *level, const char *prefix_str, int prefix_type,
154 			int rowsize, int groupsize,
155 			const void *buf, size_t len, bool ascii)
156 {
157 	const u8 *ptr = buf;
158 	int i, linelen, remaining = len;
159 	unsigned char linebuf[200];
160 
161 	if (rowsize != 16 && rowsize != 32)
162 		rowsize = 16;
163 
164 	for (i = 0; i < len; i += rowsize) {
165 		linelen = min(remaining, rowsize);
166 		remaining -= rowsize;
167 		hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
168 				linebuf, sizeof(linebuf), ascii);
169 
170 		switch (prefix_type) {
171 		case DUMP_PREFIX_ADDRESS:
172 			printk("%s%s%*p: %s\n", level, prefix_str,
173 				(int)(2 * sizeof(void *)), ptr + i, linebuf);
174 			break;
175 		case DUMP_PREFIX_OFFSET:
176 			printk("%s%s%.8x: %s\n", level, prefix_str, i, linebuf);
177 			break;
178 		default:
179 			printk("%s%s%s\n", level, prefix_str, linebuf);
180 			break;
181 		}
182 	}
183 }
184 EXPORT_SYMBOL(print_hex_dump);
185 
186 /**
187  * print_hex_dump_bytes - shorthand form of print_hex_dump() with default params
188  * @prefix_str: string to prefix each line with;
189  *  caller supplies trailing spaces for alignment if desired
190  * @prefix_type: controls whether prefix of an offset, address, or none
191  *  is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
192  * @buf: data blob to dump
193  * @len: number of bytes in the @buf
194  *
195  * Calls print_hex_dump(), with log level of KERN_DEBUG,
196  * rowsize of 16, groupsize of 1, and ASCII output included.
197  */
198 void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
199 			const void *buf, size_t len)
200 {
201 	print_hex_dump(KERN_DEBUG, prefix_str, prefix_type, 16, 1,
202 			buf, len, 1);
203 }
204 EXPORT_SYMBOL(print_hex_dump_bytes);
205