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/minmax.h>
11 #include <linux/export.h>
12 #include <asm/unaligned.h>
13 
14 const char hex_asc[] = "0123456789abcdef";
15 EXPORT_SYMBOL(hex_asc);
16 const char hex_asc_upper[] = "0123456789ABCDEF";
17 EXPORT_SYMBOL(hex_asc_upper);
18 
19 /**
20  * hex_to_bin - convert a hex digit to its real value
21  * @ch: ascii character represents hex digit
22  *
23  * hex_to_bin() converts one hex digit to its actual value or -1 in case of bad
24  * input.
25  */
hex_to_bin(char ch)26 int hex_to_bin(char ch)
27 {
28 	if ((ch >= '0') && (ch <= '9'))
29 		return ch - '0';
30 	ch = tolower(ch);
31 	if ((ch >= 'a') && (ch <= 'f'))
32 		return ch - 'a' + 10;
33 	return -1;
34 }
35 EXPORT_SYMBOL(hex_to_bin);
36 
37 /**
38  * hex2bin - convert an ascii hexadecimal string to its binary representation
39  * @dst: binary result
40  * @src: ascii hexadecimal string
41  * @count: result length
42  *
43  * Return 0 on success, -EINVAL in case of bad input.
44  */
hex2bin(u8 * dst,const char * src,size_t count)45 int hex2bin(u8 *dst, const char *src, size_t count)
46 {
47 	while (count--) {
48 		int hi = hex_to_bin(*src++);
49 		int lo = hex_to_bin(*src++);
50 
51 		if ((hi < 0) || (lo < 0))
52 			return -EINVAL;
53 
54 		*dst++ = (hi << 4) | lo;
55 	}
56 	return 0;
57 }
58 EXPORT_SYMBOL(hex2bin);
59 
60 /**
61  * bin2hex - convert binary data to an ascii hexadecimal string
62  * @dst: ascii hexadecimal result
63  * @src: binary data
64  * @count: binary data length
65  */
bin2hex(char * dst,const void * src,size_t count)66 char *bin2hex(char *dst, const void *src, size_t count)
67 {
68 	const unsigned char *_src = src;
69 
70 	while (count--)
71 		dst = hex_byte_pack(dst, *_src++);
72 	return dst;
73 }
74 EXPORT_SYMBOL(bin2hex);
75 
76 /**
77  * hex_dump_to_buffer - convert a blob of data to "hex ASCII" in memory
78  * @buf: data blob to dump
79  * @len: number of bytes in the @buf
80  * @rowsize: number of bytes to print per line; must be 16 or 32
81  * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
82  * @linebuf: where to put the converted data
83  * @linebuflen: total size of @linebuf, including space for terminating NUL
84  * @ascii: include ASCII after the hex output
85  *
86  * hex_dump_to_buffer() works on one "line" of output at a time, i.e.,
87  * 16 or 32 bytes of input data converted to hex + ASCII output.
88  *
89  * Given a buffer of u8 data, hex_dump_to_buffer() converts the input data
90  * to a hex + ASCII dump at the supplied memory location.
91  * The converted output is always NUL-terminated.
92  *
93  * E.g.:
94  *   hex_dump_to_buffer(frame->data, frame->len, 16, 1,
95  *			linebuf, sizeof(linebuf), true);
96  *
97  * example output buffer:
98  * 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f  @ABCDEFGHIJKLMNO
99  *
100  * Return:
101  * The amount of bytes placed in the buffer without terminating NUL. If the
102  * output was truncated, then the return value is the number of bytes
103  * (excluding the terminating NUL) which would have been written to the final
104  * string if enough space had been available.
105  */
hex_dump_to_buffer(const void * buf,size_t len,int rowsize,int groupsize,char * linebuf,size_t linebuflen,bool ascii)106 int hex_dump_to_buffer(const void *buf, size_t len, int rowsize, int groupsize,
107 		       char *linebuf, size_t linebuflen, bool ascii)
108 {
109 	const u8 *ptr = buf;
110 	int ngroups;
111 	u8 ch;
112 	int j, lx = 0;
113 	int ascii_column;
114 	int ret;
115 
116 	if (rowsize != 16 && rowsize != 32)
117 		rowsize = 16;
118 
119 	if (len > rowsize)		/* limit to one line at a time */
120 		len = rowsize;
121 	if (!is_power_of_2(groupsize) || groupsize > 8)
122 		groupsize = 1;
123 	if ((len % groupsize) != 0)	/* no mixed size output */
124 		groupsize = 1;
125 
126 	ngroups = len / groupsize;
127 	ascii_column = rowsize * 2 + rowsize / groupsize + 1;
128 
129 	if (!linebuflen)
130 		goto overflow1;
131 
132 	if (!len)
133 		goto nil;
134 
135 	if (groupsize == 8) {
136 		const u64 *ptr8 = buf;
137 
138 		for (j = 0; j < ngroups; j++) {
139 			ret = snprintf(linebuf + lx, linebuflen - lx,
140 				       "%s%16.16llx", j ? " " : "",
141 				       get_unaligned(ptr8 + j));
142 			if (ret >= linebuflen - lx)
143 				goto overflow1;
144 			lx += ret;
145 		}
146 	} else if (groupsize == 4) {
147 		const u32 *ptr4 = buf;
148 
149 		for (j = 0; j < ngroups; j++) {
150 			ret = snprintf(linebuf + lx, linebuflen - lx,
151 				       "%s%8.8x", j ? " " : "",
152 				       get_unaligned(ptr4 + j));
153 			if (ret >= linebuflen - lx)
154 				goto overflow1;
155 			lx += ret;
156 		}
157 	} else if (groupsize == 2) {
158 		const u16 *ptr2 = buf;
159 
160 		for (j = 0; j < ngroups; j++) {
161 			ret = snprintf(linebuf + lx, linebuflen - lx,
162 				       "%s%4.4x", j ? " " : "",
163 				       get_unaligned(ptr2 + j));
164 			if (ret >= linebuflen - lx)
165 				goto overflow1;
166 			lx += ret;
167 		}
168 	} else {
169 		for (j = 0; j < len; j++) {
170 			if (linebuflen < lx + 2)
171 				goto overflow2;
172 			ch = ptr[j];
173 			linebuf[lx++] = hex_asc_hi(ch);
174 			if (linebuflen < lx + 2)
175 				goto overflow2;
176 			linebuf[lx++] = hex_asc_lo(ch);
177 			if (linebuflen < lx + 2)
178 				goto overflow2;
179 			linebuf[lx++] = ' ';
180 		}
181 		if (j)
182 			lx--;
183 	}
184 	if (!ascii)
185 		goto nil;
186 
187 	while (lx < ascii_column) {
188 		if (linebuflen < lx + 2)
189 			goto overflow2;
190 		linebuf[lx++] = ' ';
191 	}
192 	for (j = 0; j < len; j++) {
193 		if (linebuflen < lx + 2)
194 			goto overflow2;
195 		ch = ptr[j];
196 		linebuf[lx++] = (isascii(ch) && isprint(ch)) ? ch : '.';
197 	}
198 nil:
199 	linebuf[lx] = '\0';
200 	return lx;
201 overflow2:
202 	linebuf[lx++] = '\0';
203 overflow1:
204 	return ascii ? ascii_column + len : (groupsize * 2 + 1) * ngroups - 1;
205 }
206 EXPORT_SYMBOL(hex_dump_to_buffer);
207 
208 #ifdef CONFIG_PRINTK
209 /**
210  * print_hex_dump - print a text hex dump to syslog for a binary blob of data
211  * @level: kernel log level (e.g. KERN_DEBUG)
212  * @prefix_str: string to prefix each line with;
213  *  caller supplies trailing spaces for alignment if desired
214  * @prefix_type: controls whether prefix of an offset, address, or none
215  *  is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
216  * @rowsize: number of bytes to print per line; must be 16 or 32
217  * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
218  * @buf: data blob to dump
219  * @len: number of bytes in the @buf
220  * @ascii: include ASCII after the hex output
221  *
222  * Given a buffer of u8 data, print_hex_dump() prints a hex + ASCII dump
223  * to the kernel log at the specified kernel log level, with an optional
224  * leading prefix.
225  *
226  * print_hex_dump() works on one "line" of output at a time, i.e.,
227  * 16 or 32 bytes of input data converted to hex + ASCII output.
228  * print_hex_dump() iterates over the entire input @buf, breaking it into
229  * "line size" chunks to format and print.
230  *
231  * E.g.:
232  *   print_hex_dump(KERN_DEBUG, "raw data: ", DUMP_PREFIX_ADDRESS,
233  *		    16, 1, frame->data, frame->len, true);
234  *
235  * Example output using %DUMP_PREFIX_OFFSET and 1-byte mode:
236  * 0009ab42: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f  @ABCDEFGHIJKLMNO
237  * Example output using %DUMP_PREFIX_ADDRESS and 4-byte mode:
238  * ffffffff88089af0: 73727170 77767574 7b7a7978 7f7e7d7c  pqrstuvwxyz{|}~.
239  */
print_hex_dump(const char * level,const char * prefix_str,int prefix_type,int rowsize,int groupsize,const void * buf,size_t len,bool ascii)240 void print_hex_dump(const char *level, const char *prefix_str, int prefix_type,
241 		    int rowsize, int groupsize,
242 		    const void *buf, size_t len, bool ascii)
243 {
244 	const u8 *ptr = buf;
245 	int i, linelen, remaining = len;
246 	unsigned char linebuf[32 * 3 + 2 + 32 + 1];
247 
248 	if (rowsize != 16 && rowsize != 32)
249 		rowsize = 16;
250 
251 	for (i = 0; i < len; i += rowsize) {
252 		linelen = min(remaining, rowsize);
253 		remaining -= rowsize;
254 
255 		hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
256 				   linebuf, sizeof(linebuf), ascii);
257 
258 		switch (prefix_type) {
259 		case DUMP_PREFIX_ADDRESS:
260 			printk("%s%s%p: %s\n",
261 			       level, prefix_str, ptr + i, linebuf);
262 			break;
263 		case DUMP_PREFIX_OFFSET:
264 			printk("%s%s%.8x: %s\n", level, prefix_str, i, linebuf);
265 			break;
266 		default:
267 			printk("%s%s%s\n", level, prefix_str, linebuf);
268 			break;
269 		}
270 	}
271 }
272 EXPORT_SYMBOL(print_hex_dump);
273 
274 #endif /* defined(CONFIG_PRINTK) */
275