xref: /openbmc/linux/lib/hexdump.c (revision 732a675a)
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 				"%16.16llx ", (unsigned long long)*(ptr8 + j));
69 		ascii_column = 17 * ngroups + 2;
70 		break;
71 	}
72 
73 	case 4: {
74 		const u32 *ptr4 = buf;
75 		int ngroups = len / groupsize;
76 
77 		for (j = 0; j < ngroups; j++)
78 			lx += scnprintf(linebuf + lx, linebuflen - lx,
79 				"%8.8x ", *(ptr4 + j));
80 		ascii_column = 9 * ngroups + 2;
81 		break;
82 	}
83 
84 	case 2: {
85 		const u16 *ptr2 = buf;
86 		int ngroups = len / groupsize;
87 
88 		for (j = 0; j < ngroups; j++)
89 			lx += scnprintf(linebuf + lx, linebuflen - lx,
90 				"%4.4x ", *(ptr2 + j));
91 		ascii_column = 5 * ngroups + 2;
92 		break;
93 	}
94 
95 	default:
96 		for (j = 0; (j < rowsize) && (j < len) && (lx + 4) < linebuflen;
97 		     j++) {
98 			ch = ptr[j];
99 			linebuf[lx++] = hex_asc_hi(ch);
100 			linebuf[lx++] = hex_asc_lo(ch);
101 			linebuf[lx++] = ' ';
102 		}
103 		ascii_column = 3 * rowsize + 2;
104 		break;
105 	}
106 	if (!ascii)
107 		goto nil;
108 
109 	while (lx < (linebuflen - 1) && lx < (ascii_column - 1))
110 		linebuf[lx++] = ' ';
111 	for (j = 0; (j < rowsize) && (j < len) && (lx + 2) < linebuflen; j++)
112 		linebuf[lx++] = (isascii(ptr[j]) && isprint(ptr[j])) ? ptr[j]
113 				: '.';
114 nil:
115 	linebuf[lx++] = '\0';
116 }
117 EXPORT_SYMBOL(hex_dump_to_buffer);
118 
119 /**
120  * print_hex_dump - print a text hex dump to syslog for a binary blob of data
121  * @level: kernel log level (e.g. KERN_DEBUG)
122  * @prefix_str: string to prefix each line with;
123  *  caller supplies trailing spaces for alignment if desired
124  * @prefix_type: controls whether prefix of an offset, address, or none
125  *  is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
126  * @rowsize: number of bytes to print per line; must be 16 or 32
127  * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
128  * @buf: data blob to dump
129  * @len: number of bytes in the @buf
130  * @ascii: include ASCII after the hex output
131  *
132  * Given a buffer of u8 data, print_hex_dump() prints a hex + ASCII dump
133  * to the kernel log at the specified kernel log level, with an optional
134  * leading prefix.
135  *
136  * print_hex_dump() works on one "line" of output at a time, i.e.,
137  * 16 or 32 bytes of input data converted to hex + ASCII output.
138  * print_hex_dump() iterates over the entire input @buf, breaking it into
139  * "line size" chunks to format and print.
140  *
141  * E.g.:
142  *   print_hex_dump(KERN_DEBUG, "raw data: ", DUMP_PREFIX_ADDRESS,
143  *		16, 1, frame->data, frame->len, 1);
144  *
145  * Example output using %DUMP_PREFIX_OFFSET and 1-byte mode:
146  * 0009ab42: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f  @ABCDEFGHIJKLMNO
147  * Example output using %DUMP_PREFIX_ADDRESS and 4-byte mode:
148  * ffffffff88089af0: 73727170 77767574 7b7a7978 7f7e7d7c  pqrstuvwxyz{|}~.
149  */
150 void print_hex_dump(const char *level, const char *prefix_str, int prefix_type,
151 			int rowsize, int groupsize,
152 			const void *buf, size_t len, bool ascii)
153 {
154 	const u8 *ptr = buf;
155 	int i, linelen, remaining = len;
156 	unsigned char linebuf[200];
157 
158 	if (rowsize != 16 && rowsize != 32)
159 		rowsize = 16;
160 
161 	for (i = 0; i < len; i += rowsize) {
162 		linelen = min(remaining, rowsize);
163 		remaining -= rowsize;
164 		hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
165 				linebuf, sizeof(linebuf), ascii);
166 
167 		switch (prefix_type) {
168 		case DUMP_PREFIX_ADDRESS:
169 			printk("%s%s%*p: %s\n", level, prefix_str,
170 				(int)(2 * sizeof(void *)), ptr + i, linebuf);
171 			break;
172 		case DUMP_PREFIX_OFFSET:
173 			printk("%s%s%.8x: %s\n", level, prefix_str, i, linebuf);
174 			break;
175 		default:
176 			printk("%s%s%s\n", level, prefix_str, linebuf);
177 			break;
178 		}
179 	}
180 }
181 EXPORT_SYMBOL(print_hex_dump);
182 
183 /**
184  * print_hex_dump_bytes - shorthand form of print_hex_dump() with default params
185  * @prefix_str: string to prefix each line with;
186  *  caller supplies trailing spaces for alignment if desired
187  * @prefix_type: controls whether prefix of an offset, address, or none
188  *  is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
189  * @buf: data blob to dump
190  * @len: number of bytes in the @buf
191  *
192  * Calls print_hex_dump(), with log level of KERN_DEBUG,
193  * rowsize of 16, groupsize of 1, and ASCII output included.
194  */
195 void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
196 			const void *buf, size_t len)
197 {
198 	print_hex_dump(KERN_DEBUG, prefix_str, prefix_type, 16, 1,
199 			buf, len, 1);
200 }
201 EXPORT_SYMBOL(print_hex_dump_bytes);
202