linux-6.12.1/lib/hexdump.c

1 // SPDX-License-Identifier: GPL-2.0-only
20  * hex_to_bin - convert a hex digit to its real value
23  * hex_to_bin() converts one hex digit to its actual value or -1 in case of bad
26  * This function is used to load cryptographic keys, so it is coded in such a
30  * (ch - '9' - 1) is negative if ch <= '9'
31  * ('0' - 1 - ch) is negative if ch >= '0'
33  *	'0' ... '9'
34  * we are only interested in the sign, so we do a shift ">> 8"; note that right
35  *	shift of a negative value is implementation-defined, so we cast the
36  *	value to (unsigned) before the shift --- we have 0xffffff if ch is in
37  *	the range '0' ... '9', 0 otherwise
38  * we "and" this value with (ch - '0' + 1) --- we have a value 1 ... 10 if ch is
39  *	in the range '0' ... '9', 0 otherwise
40  * we add this value to -1 --- we have a value 0 ... 9 if ch is in the range '0'
41  *	... '9', -1 otherwise
49 	return -1 +  in hex_to_bin()
50 		((ch - '0' +  1) & (unsigned)((ch - '9' - 1) & ('0' - 1 - ch)) >> 8) +  in hex_to_bin()
51 		((cu - 'A' + 11) & (unsigned)((cu - 'F' - 1) & ('A' - 1 - cu)) >> 8);  in hex_to_bin()
56  * hex2bin - convert an ascii hexadecimal string to its binary representation
61  * Return 0 on success, -EINVAL in case of bad input.
65 	while (count--) {  in hex2bin()
70 			return -EINVAL;  in hex2bin()
73 			return -EINVAL;  in hex2bin()
82  * bin2hex - convert binary data to an ascii hexadecimal string
91 	while (count--)  in bin2hex()
98  * hex_dump_to_buffer - convert a blob of data to "hex ASCII" in memory
102  * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
107  * hex_dump_to_buffer() works on one "line" of output at a time, i.e.,
110  * Given a buffer of u8 data, hex_dump_to_buffer() converts the input data
111  * to a hex + ASCII dump at the supplied memory location.
112  * The converted output is always NUL-terminated.
114  * E.g.:
115  *   hex_dump_to_buffer(frame->data, frame->len, 16, 1,
119  * 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f  @ABCDEFGHIJKLMNO
140 	if (len > rowsize)		/* limit to one line at a time */  in hex_dump_to_buffer()
143 		groupsize = 1;  in hex_dump_to_buffer()
145 		groupsize = 1;  in hex_dump_to_buffer()
148 	ascii_column = rowsize * 2 + rowsize / groupsize + 1;  in hex_dump_to_buffer()
160 			ret = snprintf(linebuf + lx, linebuflen - lx,  in hex_dump_to_buffer()
163 			if (ret >= linebuflen - lx)  in hex_dump_to_buffer()
171 			ret = snprintf(linebuf + lx, linebuflen - lx,  in hex_dump_to_buffer()
174 			if (ret >= linebuflen - lx)  in hex_dump_to_buffer()
182 			ret = snprintf(linebuf + lx, linebuflen - lx,  in hex_dump_to_buffer()
185 			if (ret >= linebuflen - lx)  in hex_dump_to_buffer()
203 			lx--;  in hex_dump_to_buffer()
225 	return ascii ? ascii_column + len : (groupsize * 2 + 1) * ngroups - 1;  in hex_dump_to_buffer()
231  * print_hex_dump - print a text hex dump to syslog for a binary blob of data
232  * @level: kernel log level (e.g. KERN_DEBUG)
238  * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
243  * Given a buffer of u8 data, print_hex_dump() prints a hex + ASCII dump
247  * print_hex_dump() works on one "line" of output at a time, i.e.,
252  * E.g.:
254  *		    16, 1, frame->data, frame->len, true);
256  * Example output using %DUMP_PREFIX_OFFSET and 1-byte mode:
257  * 0009ab42: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f  @ABCDEFGHIJKLMNO
258  * Example output using %DUMP_PREFIX_ADDRESS and 4-byte mode:
267 	unsigned char linebuf[32 * 3 + 2 + 32 + 1];  in print_hex_dump()
274 		remaining -= rowsize;  in print_hex_dump()