summaryrefslogtreecommitdiffstats
path: root/src/utils.c
blob: ea0bbde0695cbf04ff657704c49a0b040284e500 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
/*
 * (C) 2011 by Harald Welte <laforge@gnumonks.org>
 * (C) 2011 by Sylvain Munaut <tnt@246tNt.com>
 * (C) 2014 by Nils O. Selåsdal <noselasd@fiane.dyndns.org>
 *
 * All Rights Reserved
 *
 * SPDX-License-Identifier: GPL-2.0+
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 */


#include <stdbool.h>
#include <string.h>
#include <stdint.h>
#include <errno.h>
#include <stdio.h>
#include <inttypes.h>

#include <osmocom/core/utils.h>
#include <osmocom/core/bit64gen.h>


/*! \addtogroup utils
 * @{
 * various utility routines
 *
 * \file utils.c */

static char namebuf[255];

/*! get human-readable string for given value
 *  \param[in] vs Array of value_string tuples
 *  \param[in] val Value to be converted
 *  \returns pointer to human-readable string
 *
 * If val is found in vs, the array's string entry is returned. Otherwise, an
 * "unknown" string containing the actual value is composed in a static buffer
 * that is reused across invocations.
 */
const char *get_value_string(const struct value_string *vs, uint32_t val)
{
	const char *str = get_value_string_or_null(vs, val);
	if (str)
		return str;

	snprintf(namebuf, sizeof(namebuf), "unknown 0x%"PRIx32, val);
	namebuf[sizeof(namebuf) - 1] = '\0';
	return namebuf;
}

/*! get human-readable string or NULL for given value
 *  \param[in] vs Array of value_string tuples
 *  \param[in] val Value to be converted
 *  \returns pointer to human-readable string or NULL if val is not found
 */
const char *get_value_string_or_null(const struct value_string *vs,
				     uint32_t val)
{
	int i;

	for (i = 0;; i++) {
		if (vs[i].value == 0 && vs[i].str == NULL)
			break;
		if (vs[i].value == val)
			return vs[i].str;
	}

	return NULL;
}

/*! get numeric value for given human-readable string
 *  \param[in] vs Array of value_string tuples
 *  \param[in] str human-readable string
 *  \returns numeric value (>0) or negative numer in case of error
 */
int get_string_value(const struct value_string *vs, const char *str)
{
	int i;

	for (i = 0;; i++) {
		if (vs[i].value == 0 && vs[i].str == NULL)
			break;
		if (!strcasecmp(vs[i].str, str))
			return vs[i].value;
	}
	return -EINVAL;
}

/*! Convert BCD-encoded digit into printable character
 *  \param[in] bcd A single BCD-encoded digit
 *  \returns single printable character
 */
char osmo_bcd2char(uint8_t bcd)
{
	if (bcd < 0xa)
		return '0' + bcd;
	else
		return 'A' + (bcd - 0xa);
}

/*! Convert number in ASCII to BCD value
 *  \param[in] c ASCII character
 *  \returns BCD encoded value of character
 */
uint8_t osmo_char2bcd(char c)
{
	if (c >= '0' && c <= '9')
		return c - 0x30;
	else if (c >= 'A' && c <= 'F')
		return 0xa + (c - 'A');
	else if (c >= 'a' && c <= 'f')
		return 0xa + (c - 'a');
	else
		return 0;
}

/*! Parse a string containing hexadecimal digits
 *  \param[in] str string containing ASCII encoded hexadecimal digits
 *  \param[out] b output buffer
 *  \param[in] max_len maximum space in output buffer
 *  \returns number of parsed octets, or -1 on error
 */
int osmo_hexparse(const char *str, uint8_t *b, int max_len)

{
	char c;
	uint8_t v;
	const char *strpos;
	unsigned int nibblepos = 0;

	memset(b, 0x00, max_len);

	for (strpos = str; (c = *strpos); strpos++) {
		/* skip whitespace */
		if (c == ' ' || c == '\t' || c == '\n' || c == '\r')
			continue;

		/* If the buffer is too small, error out */
		if (nibblepos >= (max_len << 1))
			return -1;

		if (c >= '0' && c <= '9')
			v = c - '0';
		else if (c >= 'a' && c <= 'f')
			v = 10 + (c - 'a');
		else if (c >= 'A' && c <= 'F')
			v = 10 + (c - 'A');
		else
			return -1;

		b[nibblepos >> 1] |= v << (nibblepos & 1 ? 0 : 4);
		nibblepos ++;
	}

	/* In case of uneven amount of digits, the last byte is not complete
	 * and that's an error. */
	if (nibblepos & 1)
		return -1;

	return nibblepos >> 1;
}

static char hexd_buff[4096];
static const char hex_chars[] = "0123456789abcdef";

static char *_osmo_hexdump(const unsigned char *buf, int len, char *delim)
{
	int i;
	char *cur = hexd_buff;

	hexd_buff[0] = 0;
	for (i = 0; i < len; i++) {
		const char *delimp = delim;
		int len_remain = sizeof(hexd_buff) - (cur - hexd_buff);
		if (len_remain < 3)
			break;

		*cur++ = hex_chars[buf[i] >> 4];
		*cur++ = hex_chars[buf[i] & 0xf];

		while (len_remain > 1 && *delimp) {
			*cur++ = *delimp++;
			len_remain--;
		}

		*cur = 0;
	}
	hexd_buff[sizeof(hexd_buff)-1] = 0;
	return hexd_buff;
}

/*! Convert a sequence of unpacked bits to ASCII string
 * \param[in] bits A sequence of unpacked bits
 * \param[in] len Length of bits
 */
char *osmo_ubit_dump(const uint8_t *bits, unsigned int len)
{
	int i;

	if (len > sizeof(hexd_buff)-1)
		len = sizeof(hexd_buff)-1;
	memset(hexd_buff, 0, sizeof(hexd_buff));

	for (i = 0; i < len; i++) {
		char outch;
		switch (bits[i]) {
		case 0:
			outch = '0';
			break;
		case 0xff:
			outch = '?';
			break;
		case 1:
			outch = '1';
			break;
		default:
			outch = 'E';
			break;
		}
		hexd_buff[i] = outch;
	}
	hexd_buff[sizeof(hexd_buff)-1] = 0;
	return hexd_buff;
}

/*! Convert binary sequence to hexadecimal ASCII string
 *  \param[in] buf pointer to sequence of bytes
 *  \param[in] len length of buf in number of bytes
 *  \returns pointer to zero-terminated string
 *
 * This function will print a sequence of bytes as hexadecimal numbers,
 * adding one space character between each byte (e.g. "1a ef d9")
 *
 * The maximum size of the output buffer is 4096 bytes, i.e. the maximum
 * number of input bytes that can be printed in one call is 1365!
 */
char *osmo_hexdump(const unsigned char *buf, int len)
{
	return _osmo_hexdump(buf, len, " ");
}

/*! Convert binary sequence to hexadecimal ASCII string
 *  \param[in] buf pointer to sequence of bytes
 *  \param[in] len length of buf in number of bytes
 *  \returns pointer to zero-terminated string
 *
 * This function will print a sequence of bytes as hexadecimal numbers,
 * without any space character between each byte (e.g. "1aefd9")
 *
 * The maximum size of the output buffer is 4096 bytes, i.e. the maximum
 * number of input bytes that can be printed in one call is 2048!
 */
char *osmo_hexdump_nospc(const unsigned char *buf, int len)
{
	return _osmo_hexdump(buf, len, "");
}

/* Compat with previous typo to preserve abi */
char *osmo_osmo_hexdump_nospc(const unsigned char *buf, int len)
#if defined(__MACH__) && defined(__APPLE__)
	;
#else
	__attribute__((weak, alias("osmo_hexdump_nospc")));
#endif

#include "../config.h"
#ifdef HAVE_CTYPE_H
#include <ctype.h>
/*! Convert an entire string to lower case
 *  \param[out] out output string, caller-allocated
 *  \param[in] in input string
 */
void osmo_str2lower(char *out, const char *in)
{
	unsigned int i;

	for (i = 0; i < strlen(in); i++)
		out[i] = tolower((const unsigned char)in[i]);
	out[strlen(in)] = '\0';
}

/*! Convert an entire string to upper case
 *  \param[out] out output string, caller-allocated
 *  \param[in] in input string
 */
void osmo_str2upper(char *out, const char *in)
{
	unsigned int i;

	for (i = 0; i < strlen(in); i++)
		out[i] = toupper((const unsigned char)in[i]);
	out[strlen(in)] = '\0';
}
#endif /* HAVE_CTYPE_H */

/*! Wishful thinking to generate a constant time compare
 *  \param[in] exp Expected data
 *  \param[in] rel Comparison value
 *  \param[in] count Number of bytes to compare
 *  \returns 1 in case \a exp equals \a rel; zero otherwise
 *
 * Compare count bytes of exp to rel. Return 0 if they are identical, 1
 * otherwise. Do not return a mismatch on the first mismatching byte,
 * but always compare all bytes, regardless. The idea is that the amount of
 * matching bytes cannot be inferred from the time the comparison took. */
int osmo_constant_time_cmp(const uint8_t *exp, const uint8_t *rel, const int count)
{
	int x = 0, i;

	for (i = 0; i < count; ++i)
		x |= exp[i] ^ rel[i];

	/* if x is zero, all data was identical */
	return x? 1 : 0;
}

/*! Generic retrieval of 1..8 bytes as big-endian uint64_t
 *  \param[in] data Input data as byte-array
 *  \param[in] data_len Length of \a data in octets
 *  \returns uint64_t of \a data interpreted as big-endian
 *
 * This is like osmo_load64be_ext, except that if data_len is less than
 * sizeof(uint64_t), the data is interpreted as the least significant bytes
 * (osmo_load64be_ext loads them as the most significant bytes into the
 * returned uint64_t). In this way, any integer size up to 64 bits can be
 * decoded conveniently by using sizeof(), without the need to call specific
 * numbered functions (osmo_load16, 32, ...). */
uint64_t osmo_decode_big_endian(const uint8_t *data, size_t data_len)
{
	uint64_t value = 0;

	while (data_len > 0) {
		value = (value << 8) + *data;
		data += 1;
		data_len -= 1;
	}

	return value;
}

/*! Generic big-endian encoding of big endian number up to 64bit
 *  \param[in] value unsigned integer value to be stored
 *  \param[in] data_len number of octets 
 *  \returns static buffer containing big-endian stored value
 *
 * This is like osmo_store64be_ext, except that this returns a static buffer of
 * the result (for convenience, but not threadsafe). If data_len is less than
 * sizeof(uint64_t), only the least significant bytes of value are encoded. */
uint8_t *osmo_encode_big_endian(uint64_t value, size_t data_len)
{
	static uint8_t buf[sizeof(uint64_t)];
	OSMO_ASSERT(data_len <= ARRAY_SIZE(buf));
	osmo_store64be_ext(value, buf, data_len);
	return buf;
}

/*! Copy a C-string into a sized buffer
 *  \param[in] src source string
 *  \param[out] dst destination string
 *  \param[in] siz size of the \a dst buffer
 *  \returns length of \a src
 *
 * Copy at most \a siz bytes from \a src to \a dst, ensuring that the result is
 * NUL terminated. The NUL character is included in \a siz, i.e. passing the
 * actual sizeof(*dst) is correct.
 */
size_t osmo_strlcpy(char *dst, const char *src, size_t siz)
{
	size_t ret = src ? strlen(src) : 0;

	if (siz) {
		size_t len = (ret >= siz) ? siz - 1 : ret;
		if (src)
			memcpy(dst, src, len);
		dst[len] = '\0';
	}
	return ret;
}

/*! Validate that a given string is a hex string within given size limits.
 * Note that each hex digit amounts to a nibble, so if checking for a hex
 * string to result in N bytes, pass amount of digits as 2*N.
 * \param str  A nul-terminated string to validate, or NULL.
 * \param min_digits  least permitted amount of digits.
 * \param max_digits  most permitted amount of digits.
 * \param require_even  if true, require an even amount of digits.
 * \returns true when the hex_str contains only hexadecimal digits (no
 *          whitespace) and matches the requested length; also true
 *          when min_digits <= 0 and str is NULL.
 */
bool osmo_is_hexstr(const char *str, int min_digits, int max_digits,
		    bool require_even)
{
	int len;
	/* Use unsigned char * to avoid a compiler warning of
	 * "error: array subscript has type 'char' [-Werror=char-subscripts]" */
	const unsigned char *pos = (const unsigned char*)str;
	if (!pos)
		return min_digits < 1;
	for (len = 0; *pos && len < max_digits; len++, pos++)
		if (!isxdigit(*pos))
			return false;
	if (len < min_digits)
		return false;
	/* With not too many digits, we should have reached *str == nul */
	if (*pos)
		return false;
	if (require_even && (len & 1))
		return false;

	return true;
}

/*! Determine if a given identifier is valid, i.e. doesn't contain illegal chars
 *  \param[in] str String to validate
 *  \param[in] sep_chars Permitted separation characters between identifiers.
 *  \returns true in case \a str contains only valid identifiers and sep_chars, false otherwise
 */
bool osmo_separated_identifiers_valid(const char *str, const char *sep_chars)
{
	/* characters that are illegal in names */
	static const char illegal_chars[] = "., {}[]()<>|~\\^`'\"?=;/+*&%$#!";
	unsigned int i;
	size_t len;

	/* an empty string is not a valid identifier */
	if (!str || (len = strlen(str)) == 0)
		return false;

	for (i = 0; i < len; i++) {
		if (sep_chars && strchr(sep_chars, str[i]))
			continue;
		/* check for 7-bit ASCII */
		if (str[i] & 0x80)
			return false;
		if (!isprint((int)str[i]))
			return false;
		/* check for some explicit reserved control characters */
		if (strchr(illegal_chars, str[i]))
			return false;
	}

	return true;
}

/*! Determine if a given identifier is valid, i.e. doesn't contain illegal chars
 *  \param[in] str String to validate
 *  \returns true in case \a str contains valid identifier, false otherwise
 */
bool osmo_identifier_valid(const char *str)
{
	return osmo_separated_identifiers_valid(str, NULL);
}

/*! Return the string with all non-printable characters escaped.
 * \param[in] str  A string that may contain any characters.
 * \param[in] len  Pass -1 to print until nul char, or >= 0 to force a length.
 * \param[inout] buf  string buffer to write escaped characters to.
 * \param[in] bufsize  size of \a buf.
 * \returns buf containing an escaped representation, possibly truncated, or str itself.
 */
const char *osmo_escape_str_buf(const char *str, int in_len, char *buf, size_t bufsize)
{
	int in_pos = 0;
	int next_unprintable = 0;
	int out_pos = 0;
	char *out = buf;
	/* -1 to leave space for a final \0 */
	int out_len = bufsize-1;

	if (!str)
		return "(null)";

	if (in_len < 0)
		in_len = strlen(str);

	while (in_pos < in_len) {
		for (next_unprintable = in_pos;
		     next_unprintable < in_len && isprint((int)str[next_unprintable])
		     && str[next_unprintable] != '"'
		     && str[next_unprintable] != '\\';
		     next_unprintable++);

		if (next_unprintable == in_len
		    && in_pos == 0)
			return str;

		while (in_pos < next_unprintable && out_pos < out_len)
			out[out_pos++] = str[in_pos++];

		if (out_pos == out_len || in_pos == in_len)
			goto done;

		switch (str[next_unprintable]) {
#define BACKSLASH_CASE(c, repr) \
		case c: \
			if (out_pos > out_len-2) \
				goto done; \
			out[out_pos++] = '\\'; \
			out[out_pos++] = repr; \
			break

		BACKSLASH_CASE('\n', 'n');
		BACKSLASH_CASE('\r', 'r');
		BACKSLASH_CASE('\t', 't');
		BACKSLASH_CASE('\0', '0');
		BACKSLASH_CASE('\a', 'a');
		BACKSLASH_CASE('\b', 'b');
		BACKSLASH_CASE('\v', 'v');
		BACKSLASH_CASE('\f', 'f');
		BACKSLASH_CASE('\\', '\\');
		BACKSLASH_CASE('"', '"');
#undef BACKSLASH_CASE

		default:
			out_pos += snprintf(&out[out_pos], out_len - out_pos, "\\%u", (unsigned char)str[in_pos]);
			if (out_pos > out_len) {
				out_pos = out_len;
				goto done;
			}
			break;
		}
		in_pos ++;
	}

done:
	out[out_pos] = '\0';
	return out;
}

/*! Return the string with all non-printable characters escaped.
 * Call osmo_escape_str_buf() with a static buffer.
 * \param[in] str  A string that may contain any characters.
 * \param[in] len  Pass -1 to print until nul char, or >= 0 to force a length.
 * \returns buf containing an escaped representation, possibly truncated, or str itself.
 */
const char *osmo_escape_str(const char *str, int in_len)
{
	return osmo_escape_str_buf(str, in_len, namebuf, sizeof(namebuf));
}

/*! Like osmo_escape_str(), but returns double-quotes around a string, or "NULL" for a NULL string.
 * This allows passing any char* value and get its C representation as string.
 * \param[in] str  A string that may contain any characters.
 * \param[in] len  Pass -1 to print until nul char, or >= 0 to force a length.
 * \returns buf containing an escaped representation, possibly truncated, or str itself.
 */
const char *osmo_quote_str_buf(const char *str, int in_len, char *buf, size_t bufsize)
{
	const char *res;
	int l;
	if (!str)
		return "NULL";
	if (bufsize < 3)
		return "<buf-too-small>";
	buf[0] = '"';
	res = osmo_escape_str_buf(str, in_len, buf + 1, bufsize - 2);
	/* if osmo_escape_str_buf() returned the str itself, we need to copy it to buf to be able to
	 * quote it. */
	if (res == str) {
		/* max_len = bufsize - two quotes - nul term */
		int max_len = bufsize - 2 - 1;
		if (in_len >= 0)
			max_len = OSMO_MIN(in_len, max_len);
		/* It is not allowed to pass unterminated strings into osmo_strlcpy() :/ */
		strncpy(buf + 1, str, max_len);
		buf[1 + max_len] = '\0';
	}
	l = strlen(buf);
	buf[l] = '"';
	buf[l+1] = '\0'; /* both osmo_escape_str_buf() and max_len above ensure room for '\0' */
	return buf;
}

const char *osmo_quote_str(const char *str, int in_len)
{
	return osmo_quote_str_buf(str, in_len, namebuf, sizeof(namebuf));
}

/*! perform an integer square root operation on unsigned 32bit integer.
 *  This implementation is taken from "Hacker's Delight" Figure 11-1 "Integer square root, Newton's
 *  method", which can also be found at http://www.hackersdelight.org/hdcodetxt/isqrt.c.txt */
uint32_t osmo_isqrt32(uint32_t x)
{
	uint32_t x1;
	int s, g0, g1;

	if (x <= 1)
		return x;

	s = 1;
	x1 = x - 1;
	if (x1 > 0xffff) {
		s = s + 8;
		x1 = x1 >> 16;
	}
	if (x1 > 0xff) {
		s = s + 4;
		x1 = x1 >> 8;
	}
	if (x1 > 0xf) {
		s = s + 2;
		x1 = x1 >> 4;
	}
	if (x1 > 0x3) {
		s = s + 1;
	}

	g0 = 1 << s;			/* g0 = 2**s */
	g1 = (g0 + (x >> s)) >> 1;	/* g1 = (g0 + x/g0)/2 */

	/* converges after four to five divisions for arguments up to 16,785,407 */
	while (g1 < g0) {
		g0 = g1;
		g1 = (g0 + (x/g0)) >> 1;
	}
	return g0;
}

/*! @} */