xref: /openbmc/linux/lib/hexdump.c (revision 2eb5f31b)
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/export.h>
14  #include <asm/unaligned.h>
15  
16  const char hex_asc[] = "0123456789abcdef";
17  EXPORT_SYMBOL(hex_asc);
18  const char hex_asc_upper[] = "0123456789ABCDEF";
19  EXPORT_SYMBOL(hex_asc_upper);
20  
21  /**
22   * hex_to_bin - convert a hex digit to its real value
23   * @ch: ascii character represents hex digit
24   *
25   * hex_to_bin() converts one hex digit to its actual value or -1 in case of bad
26   * input.
27   */
28  int hex_to_bin(char ch)
29  {
30  	if ((ch >= '0') && (ch <= '9'))
31  		return ch - '0';
32  	ch = tolower(ch);
33  	if ((ch >= 'a') && (ch <= 'f'))
34  		return ch - 'a' + 10;
35  	return -1;
36  }
37  EXPORT_SYMBOL(hex_to_bin);
38  
39  /**
40   * hex2bin - convert an ascii hexadecimal string to its binary representation
41   * @dst: binary result
42   * @src: ascii hexadecimal string
43   * @count: result length
44   *
45   * Return 0 on success, -1 in case of bad input.
46   */
47  int hex2bin(u8 *dst, const char *src, size_t count)
48  {
49  	while (count--) {
50  		int hi = hex_to_bin(*src++);
51  		int lo = hex_to_bin(*src++);
52  
53  		if ((hi < 0) || (lo < 0))
54  			return -1;
55  
56  		*dst++ = (hi << 4) | lo;
57  	}
58  	return 0;
59  }
60  EXPORT_SYMBOL(hex2bin);
61  
62  /**
63   * bin2hex - convert binary data to an ascii hexadecimal string
64   * @dst: ascii hexadecimal result
65   * @src: binary data
66   * @count: binary data length
67   */
68  char *bin2hex(char *dst, const void *src, size_t count)
69  {
70  	const unsigned char *_src = src;
71  
72  	while (count--)
73  		dst = hex_byte_pack(dst, *_src++);
74  	return dst;
75  }
76  EXPORT_SYMBOL(bin2hex);
77  
78  /**
79   * hex_dump_to_buffer - convert a blob of data to "hex ASCII" in memory
80   * @buf: data blob to dump
81   * @len: number of bytes in the @buf
82   * @rowsize: number of bytes to print per line; must be 16 or 32
83   * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
84   * @linebuf: where to put the converted data
85   * @linebuflen: total size of @linebuf, including space for terminating NUL
86   * @ascii: include ASCII after the hex output
87   *
88   * hex_dump_to_buffer() works on one "line" of output at a time, i.e.,
89   * 16 or 32 bytes of input data converted to hex + ASCII output.
90   *
91   * Given a buffer of u8 data, hex_dump_to_buffer() converts the input data
92   * to a hex + ASCII dump at the supplied memory location.
93   * The converted output is always NUL-terminated.
94   *
95   * E.g.:
96   *   hex_dump_to_buffer(frame->data, frame->len, 16, 1,
97   *			linebuf, sizeof(linebuf), true);
98   *
99   * example output buffer:
100   * 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f  @ABCDEFGHIJKLMNO
101   *
102   * Return:
103   * The amount of bytes placed in the buffer without terminating NUL. If the
104   * output was truncated, then the return value is the number of bytes
105   * (excluding the terminating NUL) which would have been written to the final
106   * string if enough space had been available.
107   */
108  int hex_dump_to_buffer(const void *buf, size_t len, int rowsize, int groupsize,
109  		       char *linebuf, size_t linebuflen, bool ascii)
110  {
111  	const u8 *ptr = buf;
112  	int ngroups;
113  	u8 ch;
114  	int j, lx = 0;
115  	int ascii_column;
116  	int ret;
117  
118  	if (rowsize != 16 && rowsize != 32)
119  		rowsize = 16;
120  
121  	if (len > rowsize)		/* limit to one line at a time */
122  		len = rowsize;
123  	if (!is_power_of_2(groupsize) || groupsize > 8)
124  		groupsize = 1;
125  	if ((len % groupsize) != 0)	/* no mixed size output */
126  		groupsize = 1;
127  
128  	ngroups = len / groupsize;
129  	ascii_column = rowsize * 2 + rowsize / groupsize + 1;
130  
131  	if (!linebuflen)
132  		goto overflow1;
133  
134  	if (!len)
135  		goto nil;
136  
137  	if (groupsize == 8) {
138  		const u64 *ptr8 = buf;
139  
140  		for (j = 0; j < ngroups; j++) {
141  			ret = snprintf(linebuf + lx, linebuflen - lx,
142  				       "%s%16.16llx", j ? " " : "",
143  				       get_unaligned(ptr8 + j));
144  			if (ret >= linebuflen - lx)
145  				goto overflow1;
146  			lx += ret;
147  		}
148  	} else if (groupsize == 4) {
149  		const u32 *ptr4 = buf;
150  
151  		for (j = 0; j < ngroups; j++) {
152  			ret = snprintf(linebuf + lx, linebuflen - lx,
153  				       "%s%8.8x", j ? " " : "",
154  				       get_unaligned(ptr4 + j));
155  			if (ret >= linebuflen - lx)
156  				goto overflow1;
157  			lx += ret;
158  		}
159  	} else if (groupsize == 2) {
160  		const u16 *ptr2 = buf;
161  
162  		for (j = 0; j < ngroups; j++) {
163  			ret = snprintf(linebuf + lx, linebuflen - lx,
164  				       "%s%4.4x", j ? " " : "",
165  				       get_unaligned(ptr2 + j));
166  			if (ret >= linebuflen - lx)
167  				goto overflow1;
168  			lx += ret;
169  		}
170  	} else {
171  		for (j = 0; j < len; j++) {
172  			if (linebuflen < lx + 3)
173  				goto overflow2;
174  			ch = ptr[j];
175  			linebuf[lx++] = hex_asc_hi(ch);
176  			linebuf[lx++] = hex_asc_lo(ch);
177  			linebuf[lx++] = ' ';
178  		}
179  		if (j)
180  			lx--;
181  	}
182  	if (!ascii)
183  		goto nil;
184  
185  	while (lx < ascii_column) {
186  		if (linebuflen < lx + 2)
187  			goto overflow2;
188  		linebuf[lx++] = ' ';
189  	}
190  	for (j = 0; j < len; j++) {
191  		if (linebuflen < lx + 2)
192  			goto overflow2;
193  		ch = ptr[j];
194  		linebuf[lx++] = (isascii(ch) && isprint(ch)) ? ch : '.';
195  	}
196  nil:
197  	linebuf[lx] = '\0';
198  	return lx;
199  overflow2:
200  	linebuf[lx++] = '\0';
201  overflow1:
202  	return ascii ? ascii_column + len : (groupsize * 2 + 1) * ngroups - 1;
203  }
204  EXPORT_SYMBOL(hex_dump_to_buffer);
205  
206  #ifdef CONFIG_PRINTK
207  /**
208   * print_hex_dump - print a text hex dump to syslog for a binary blob of data
209   * @level: kernel log level (e.g. KERN_DEBUG)
210   * @prefix_str: string to prefix each line with;
211   *  caller supplies trailing spaces for alignment if desired
212   * @prefix_type: controls whether prefix of an offset, address, or none
213   *  is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
214   * @rowsize: number of bytes to print per line; must be 16 or 32
215   * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
216   * @buf: data blob to dump
217   * @len: number of bytes in the @buf
218   * @ascii: include ASCII after the hex output
219   *
220   * Given a buffer of u8 data, print_hex_dump() prints a hex + ASCII dump
221   * to the kernel log at the specified kernel log level, with an optional
222   * leading prefix.
223   *
224   * print_hex_dump() works on one "line" of output at a time, i.e.,
225   * 16 or 32 bytes of input data converted to hex + ASCII output.
226   * print_hex_dump() iterates over the entire input @buf, breaking it into
227   * "line size" chunks to format and print.
228   *
229   * E.g.:
230   *   print_hex_dump(KERN_DEBUG, "raw data: ", DUMP_PREFIX_ADDRESS,
231   *		    16, 1, frame->data, frame->len, true);
232   *
233   * Example output using %DUMP_PREFIX_OFFSET and 1-byte mode:
234   * 0009ab42: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f  @ABCDEFGHIJKLMNO
235   * Example output using %DUMP_PREFIX_ADDRESS and 4-byte mode:
236   * ffffffff88089af0: 73727170 77767574 7b7a7978 7f7e7d7c  pqrstuvwxyz{|}~.
237   */
238  void print_hex_dump(const char *level, const char *prefix_str, int prefix_type,
239  		    int rowsize, int groupsize,
240  		    const void *buf, size_t len, bool ascii)
241  {
242  	const u8 *ptr = buf;
243  	int i, linelen, remaining = len;
244  	unsigned char linebuf[32 * 3 + 2 + 32 + 1];
245  
246  	if (rowsize != 16 && rowsize != 32)
247  		rowsize = 16;
248  
249  	for (i = 0; i < len; i += rowsize) {
250  		linelen = min(remaining, rowsize);
251  		remaining -= rowsize;
252  
253  		hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
254  				   linebuf, sizeof(linebuf), ascii);
255  
256  		switch (prefix_type) {
257  		case DUMP_PREFIX_ADDRESS:
258  			printk("%s%s%p: %s\n",
259  			       level, prefix_str, ptr + i, linebuf);
260  			break;
261  		case DUMP_PREFIX_OFFSET:
262  			printk("%s%s%.8x: %s\n", level, prefix_str, i, linebuf);
263  			break;
264  		default:
265  			printk("%s%s%s\n", level, prefix_str, linebuf);
266  			break;
267  		}
268  	}
269  }
270  EXPORT_SYMBOL(print_hex_dump);
271  
272  #if !defined(CONFIG_DYNAMIC_DEBUG)
273  /**
274   * print_hex_dump_bytes - shorthand form of print_hex_dump() with default params
275   * @prefix_str: string to prefix each line with;
276   *  caller supplies trailing spaces for alignment if desired
277   * @prefix_type: controls whether prefix of an offset, address, or none
278   *  is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
279   * @buf: data blob to dump
280   * @len: number of bytes in the @buf
281   *
282   * Calls print_hex_dump(), with log level of KERN_DEBUG,
283   * rowsize of 16, groupsize of 1, and ASCII output included.
284   */
285  void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
286  			  const void *buf, size_t len)
287  {
288  	print_hex_dump(KERN_DEBUG, prefix_str, prefix_type, 16, 1,
289  		       buf, len, true);
290  }
291  EXPORT_SYMBOL(print_hex_dump_bytes);
292  #endif /* !defined(CONFIG_DYNAMIC_DEBUG) */
293  #endif /* defined(CONFIG_PRINTK) */
294