xref: /linux-6.15/lib/vsprintf.c (revision e9107f88)
1 /*
2  *  linux/lib/vsprintf.c
3  *
4  *  Copyright (C) 1991, 1992  Linus Torvalds
5  */
6 
7 /* vsprintf.c -- Lars Wirzenius & Linus Torvalds. */
8 /*
9  * Wirzenius wrote this portably, Torvalds fucked it up :-)
10  */
11 
12 /*
13  * Fri Jul 13 2001 Crutcher Dunnavant <[email protected]>
14  * - changed to provide snprintf and vsnprintf functions
15  * So Feb  1 16:51:32 CET 2004 Juergen Quade <[email protected]>
16  * - scnprintf and vscnprintf
17  */
18 
19 #include <stdarg.h>
20 #include <linux/module.h>	/* for KSYM_SYMBOL_LEN */
21 #include <linux/types.h>
22 #include <linux/string.h>
23 #include <linux/ctype.h>
24 #include <linux/kernel.h>
25 #include <linux/kallsyms.h>
26 #include <linux/math64.h>
27 #include <linux/uaccess.h>
28 #include <linux/ioport.h>
29 #include <linux/dcache.h>
30 #include <linux/cred.h>
31 #include <net/addrconf.h>
32 
33 #include <asm/page.h>		/* for PAGE_SIZE */
34 #include <asm/sections.h>	/* for dereference_function_descriptor() */
35 
36 #include "kstrtox.h"
37 
38 /**
39  * simple_strtoull - convert a string to an unsigned long long
40  * @cp: The start of the string
41  * @endp: A pointer to the end of the parsed string will be placed here
42  * @base: The number base to use
43  *
44  * This function is obsolete. Please use kstrtoull instead.
45  */
46 unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base)
47 {
48 	unsigned long long result;
49 	unsigned int rv;
50 
51 	cp = _parse_integer_fixup_radix(cp, &base);
52 	rv = _parse_integer(cp, base, &result);
53 	/* FIXME */
54 	cp += (rv & ~KSTRTOX_OVERFLOW);
55 
56 	if (endp)
57 		*endp = (char *)cp;
58 
59 	return result;
60 }
61 EXPORT_SYMBOL(simple_strtoull);
62 
63 /**
64  * simple_strtoul - convert a string to an unsigned long
65  * @cp: The start of the string
66  * @endp: A pointer to the end of the parsed string will be placed here
67  * @base: The number base to use
68  *
69  * This function is obsolete. Please use kstrtoul instead.
70  */
71 unsigned long simple_strtoul(const char *cp, char **endp, unsigned int base)
72 {
73 	return simple_strtoull(cp, endp, base);
74 }
75 EXPORT_SYMBOL(simple_strtoul);
76 
77 /**
78  * simple_strtol - convert a string to a signed long
79  * @cp: The start of the string
80  * @endp: A pointer to the end of the parsed string will be placed here
81  * @base: The number base to use
82  *
83  * This function is obsolete. Please use kstrtol instead.
84  */
85 long simple_strtol(const char *cp, char **endp, unsigned int base)
86 {
87 	if (*cp == '-')
88 		return -simple_strtoul(cp + 1, endp, base);
89 
90 	return simple_strtoul(cp, endp, base);
91 }
92 EXPORT_SYMBOL(simple_strtol);
93 
94 /**
95  * simple_strtoll - convert a string to a signed long long
96  * @cp: The start of the string
97  * @endp: A pointer to the end of the parsed string will be placed here
98  * @base: The number base to use
99  *
100  * This function is obsolete. Please use kstrtoll instead.
101  */
102 long long simple_strtoll(const char *cp, char **endp, unsigned int base)
103 {
104 	if (*cp == '-')
105 		return -simple_strtoull(cp + 1, endp, base);
106 
107 	return simple_strtoull(cp, endp, base);
108 }
109 EXPORT_SYMBOL(simple_strtoll);
110 
111 static noinline_for_stack
112 int skip_atoi(const char **s)
113 {
114 	int i = 0;
115 
116 	while (isdigit(**s))
117 		i = i*10 + *((*s)++) - '0';
118 
119 	return i;
120 }
121 
122 /* Decimal conversion is by far the most typical, and is used
123  * for /proc and /sys data. This directly impacts e.g. top performance
124  * with many processes running. We optimize it for speed
125  * using ideas described at <http://www.cs.uiowa.edu/~jones/bcd/divide.html>
126  * (with permission from the author, Douglas W. Jones).
127  */
128 
129 #if BITS_PER_LONG != 32 || BITS_PER_LONG_LONG != 64
130 /* Formats correctly any integer in [0, 999999999] */
131 static noinline_for_stack
132 char *put_dec_full9(char *buf, unsigned q)
133 {
134 	unsigned r;
135 
136 	/*
137 	 * Possible ways to approx. divide by 10
138 	 * (x * 0x1999999a) >> 32 x < 1073741829 (multiply must be 64-bit)
139 	 * (x * 0xcccd) >> 19     x <      81920 (x < 262149 when 64-bit mul)
140 	 * (x * 0x6667) >> 18     x <      43699
141 	 * (x * 0x3334) >> 17     x <      16389
142 	 * (x * 0x199a) >> 16     x <      16389
143 	 * (x * 0x0ccd) >> 15     x <      16389
144 	 * (x * 0x0667) >> 14     x <       2739
145 	 * (x * 0x0334) >> 13     x <       1029
146 	 * (x * 0x019a) >> 12     x <       1029
147 	 * (x * 0x00cd) >> 11     x <       1029 shorter code than * 0x67 (on i386)
148 	 * (x * 0x0067) >> 10     x <        179
149 	 * (x * 0x0034) >>  9     x <         69 same
150 	 * (x * 0x001a) >>  8     x <         69 same
151 	 * (x * 0x000d) >>  7     x <         69 same, shortest code (on i386)
152 	 * (x * 0x0007) >>  6     x <         19
153 	 * See <http://www.cs.uiowa.edu/~jones/bcd/divide.html>
154 	 */
155 	r      = (q * (uint64_t)0x1999999a) >> 32;
156 	*buf++ = (q - 10 * r) + '0'; /* 1 */
157 	q      = (r * (uint64_t)0x1999999a) >> 32;
158 	*buf++ = (r - 10 * q) + '0'; /* 2 */
159 	r      = (q * (uint64_t)0x1999999a) >> 32;
160 	*buf++ = (q - 10 * r) + '0'; /* 3 */
161 	q      = (r * (uint64_t)0x1999999a) >> 32;
162 	*buf++ = (r - 10 * q) + '0'; /* 4 */
163 	r      = (q * (uint64_t)0x1999999a) >> 32;
164 	*buf++ = (q - 10 * r) + '0'; /* 5 */
165 	/* Now value is under 10000, can avoid 64-bit multiply */
166 	q      = (r * 0x199a) >> 16;
167 	*buf++ = (r - 10 * q)  + '0'; /* 6 */
168 	r      = (q * 0xcd) >> 11;
169 	*buf++ = (q - 10 * r)  + '0'; /* 7 */
170 	q      = (r * 0xcd) >> 11;
171 	*buf++ = (r - 10 * q) + '0'; /* 8 */
172 	*buf++ = q + '0'; /* 9 */
173 	return buf;
174 }
175 #endif
176 
177 /* Similar to above but do not pad with zeros.
178  * Code can be easily arranged to print 9 digits too, but our callers
179  * always call put_dec_full9() instead when the number has 9 decimal digits.
180  */
181 static noinline_for_stack
182 char *put_dec_trunc8(char *buf, unsigned r)
183 {
184 	unsigned q;
185 
186 	/* Copy of previous function's body with added early returns */
187 	while (r >= 10000) {
188 		q = r + '0';
189 		r  = (r * (uint64_t)0x1999999a) >> 32;
190 		*buf++ = q - 10*r;
191 	}
192 
193 	q      = (r * 0x199a) >> 16;	/* r <= 9999 */
194 	*buf++ = (r - 10 * q)  + '0';
195 	if (q == 0)
196 		return buf;
197 	r      = (q * 0xcd) >> 11;	/* q <= 999 */
198 	*buf++ = (q - 10 * r)  + '0';
199 	if (r == 0)
200 		return buf;
201 	q      = (r * 0xcd) >> 11;	/* r <= 99 */
202 	*buf++ = (r - 10 * q) + '0';
203 	if (q == 0)
204 		return buf;
205 	*buf++ = q + '0';		 /* q <= 9 */
206 	return buf;
207 }
208 
209 /* There are two algorithms to print larger numbers.
210  * One is generic: divide by 1000000000 and repeatedly print
211  * groups of (up to) 9 digits. It's conceptually simple,
212  * but requires a (unsigned long long) / 1000000000 division.
213  *
214  * Second algorithm splits 64-bit unsigned long long into 16-bit chunks,
215  * manipulates them cleverly and generates groups of 4 decimal digits.
216  * It so happens that it does NOT require long long division.
217  *
218  * If long is > 32 bits, division of 64-bit values is relatively easy,
219  * and we will use the first algorithm.
220  * If long long is > 64 bits (strange architecture with VERY large long long),
221  * second algorithm can't be used, and we again use the first one.
222  *
223  * Else (if long is 32 bits and long long is 64 bits) we use second one.
224  */
225 
226 #if BITS_PER_LONG != 32 || BITS_PER_LONG_LONG != 64
227 
228 /* First algorithm: generic */
229 
230 static
231 char *put_dec(char *buf, unsigned long long n)
232 {
233 	if (n >= 100*1000*1000) {
234 		while (n >= 1000*1000*1000)
235 			buf = put_dec_full9(buf, do_div(n, 1000*1000*1000));
236 		if (n >= 100*1000*1000)
237 			return put_dec_full9(buf, n);
238 	}
239 	return put_dec_trunc8(buf, n);
240 }
241 
242 #else
243 
244 /* Second algorithm: valid only for 64-bit long longs */
245 
246 /* See comment in put_dec_full9 for choice of constants */
247 static noinline_for_stack
248 void put_dec_full4(char *buf, unsigned q)
249 {
250 	unsigned r;
251 	r      = (q * 0xccd) >> 15;
252 	buf[0] = (q - 10 * r) + '0';
253 	q      = (r * 0xcd) >> 11;
254 	buf[1] = (r - 10 * q)  + '0';
255 	r      = (q * 0xcd) >> 11;
256 	buf[2] = (q - 10 * r)  + '0';
257 	buf[3] = r + '0';
258 }
259 
260 /*
261  * Call put_dec_full4 on x % 10000, return x / 10000.
262  * The approximation x/10000 == (x * 0x346DC5D7) >> 43
263  * holds for all x < 1,128,869,999.  The largest value this
264  * helper will ever be asked to convert is 1,125,520,955.
265  * (d1 in the put_dec code, assuming n is all-ones).
266  */
267 static
268 unsigned put_dec_helper4(char *buf, unsigned x)
269 {
270         uint32_t q = (x * (uint64_t)0x346DC5D7) >> 43;
271 
272         put_dec_full4(buf, x - q * 10000);
273         return q;
274 }
275 
276 /* Based on code by Douglas W. Jones found at
277  * <http://www.cs.uiowa.edu/~jones/bcd/decimal.html#sixtyfour>
278  * (with permission from the author).
279  * Performs no 64-bit division and hence should be fast on 32-bit machines.
280  */
281 static
282 char *put_dec(char *buf, unsigned long long n)
283 {
284 	uint32_t d3, d2, d1, q, h;
285 
286 	if (n < 100*1000*1000)
287 		return put_dec_trunc8(buf, n);
288 
289 	d1  = ((uint32_t)n >> 16); /* implicit "& 0xffff" */
290 	h   = (n >> 32);
291 	d2  = (h      ) & 0xffff;
292 	d3  = (h >> 16); /* implicit "& 0xffff" */
293 
294 	q   = 656 * d3 + 7296 * d2 + 5536 * d1 + ((uint32_t)n & 0xffff);
295 	q = put_dec_helper4(buf, q);
296 
297 	q += 7671 * d3 + 9496 * d2 + 6 * d1;
298 	q = put_dec_helper4(buf+4, q);
299 
300 	q += 4749 * d3 + 42 * d2;
301 	q = put_dec_helper4(buf+8, q);
302 
303 	q += 281 * d3;
304 	buf += 12;
305 	if (q)
306 		buf = put_dec_trunc8(buf, q);
307 	else while (buf[-1] == '0')
308 		--buf;
309 
310 	return buf;
311 }
312 
313 #endif
314 
315 /*
316  * Convert passed number to decimal string.
317  * Returns the length of string.  On buffer overflow, returns 0.
318  *
319  * If speed is not important, use snprintf(). It's easy to read the code.
320  */
321 int num_to_str(char *buf, int size, unsigned long long num)
322 {
323 	char tmp[sizeof(num) * 3];
324 	int idx, len;
325 
326 	/* put_dec() may work incorrectly for num = 0 (generate "", not "0") */
327 	if (num <= 9) {
328 		tmp[0] = '0' + num;
329 		len = 1;
330 	} else {
331 		len = put_dec(tmp, num) - tmp;
332 	}
333 
334 	if (len > size)
335 		return 0;
336 	for (idx = 0; idx < len; ++idx)
337 		buf[idx] = tmp[len - idx - 1];
338 	return len;
339 }
340 
341 #define ZEROPAD	1		/* pad with zero */
342 #define SIGN	2		/* unsigned/signed long */
343 #define PLUS	4		/* show plus */
344 #define SPACE	8		/* space if plus */
345 #define LEFT	16		/* left justified */
346 #define SMALL	32		/* use lowercase in hex (must be 32 == 0x20) */
347 #define SPECIAL	64		/* prefix hex with "0x", octal with "0" */
348 
349 enum format_type {
350 	FORMAT_TYPE_NONE, /* Just a string part */
351 	FORMAT_TYPE_WIDTH,
352 	FORMAT_TYPE_PRECISION,
353 	FORMAT_TYPE_CHAR,
354 	FORMAT_TYPE_STR,
355 	FORMAT_TYPE_PTR,
356 	FORMAT_TYPE_PERCENT_CHAR,
357 	FORMAT_TYPE_INVALID,
358 	FORMAT_TYPE_LONG_LONG,
359 	FORMAT_TYPE_ULONG,
360 	FORMAT_TYPE_LONG,
361 	FORMAT_TYPE_UBYTE,
362 	FORMAT_TYPE_BYTE,
363 	FORMAT_TYPE_USHORT,
364 	FORMAT_TYPE_SHORT,
365 	FORMAT_TYPE_UINT,
366 	FORMAT_TYPE_INT,
367 	FORMAT_TYPE_NRCHARS,
368 	FORMAT_TYPE_SIZE_T,
369 	FORMAT_TYPE_PTRDIFF
370 };
371 
372 struct printf_spec {
373 	u8	type;		/* format_type enum */
374 	u8	flags;		/* flags to number() */
375 	u8	base;		/* number base, 8, 10 or 16 only */
376 	u8	qualifier;	/* number qualifier, one of 'hHlLtzZ' */
377 	s16	field_width;	/* width of output field */
378 	s16	precision;	/* # of digits/chars */
379 };
380 
381 static noinline_for_stack
382 char *number(char *buf, char *end, unsigned long long num,
383 	     struct printf_spec spec)
384 {
385 	/* we are called with base 8, 10 or 16, only, thus don't need "G..."  */
386 	static const char digits[16] = "0123456789ABCDEF"; /* "GHIJKLMNOPQRSTUVWXYZ"; */
387 
388 	char tmp[66];
389 	char sign;
390 	char locase;
391 	int need_pfx = ((spec.flags & SPECIAL) && spec.base != 10);
392 	int i;
393 	bool is_zero = num == 0LL;
394 
395 	/* locase = 0 or 0x20. ORing digits or letters with 'locase'
396 	 * produces same digits or (maybe lowercased) letters */
397 	locase = (spec.flags & SMALL);
398 	if (spec.flags & LEFT)
399 		spec.flags &= ~ZEROPAD;
400 	sign = 0;
401 	if (spec.flags & SIGN) {
402 		if ((signed long long)num < 0) {
403 			sign = '-';
404 			num = -(signed long long)num;
405 			spec.field_width--;
406 		} else if (spec.flags & PLUS) {
407 			sign = '+';
408 			spec.field_width--;
409 		} else if (spec.flags & SPACE) {
410 			sign = ' ';
411 			spec.field_width--;
412 		}
413 	}
414 	if (need_pfx) {
415 		if (spec.base == 16)
416 			spec.field_width -= 2;
417 		else if (!is_zero)
418 			spec.field_width--;
419 	}
420 
421 	/* generate full string in tmp[], in reverse order */
422 	i = 0;
423 	if (num < spec.base)
424 		tmp[i++] = digits[num] | locase;
425 	/* Generic code, for any base:
426 	else do {
427 		tmp[i++] = (digits[do_div(num,base)] | locase);
428 	} while (num != 0);
429 	*/
430 	else if (spec.base != 10) { /* 8 or 16 */
431 		int mask = spec.base - 1;
432 		int shift = 3;
433 
434 		if (spec.base == 16)
435 			shift = 4;
436 		do {
437 			tmp[i++] = (digits[((unsigned char)num) & mask] | locase);
438 			num >>= shift;
439 		} while (num);
440 	} else { /* base 10 */
441 		i = put_dec(tmp, num) - tmp;
442 	}
443 
444 	/* printing 100 using %2d gives "100", not "00" */
445 	if (i > spec.precision)
446 		spec.precision = i;
447 	/* leading space padding */
448 	spec.field_width -= spec.precision;
449 	if (!(spec.flags & (ZEROPAD+LEFT))) {
450 		while (--spec.field_width >= 0) {
451 			if (buf < end)
452 				*buf = ' ';
453 			++buf;
454 		}
455 	}
456 	/* sign */
457 	if (sign) {
458 		if (buf < end)
459 			*buf = sign;
460 		++buf;
461 	}
462 	/* "0x" / "0" prefix */
463 	if (need_pfx) {
464 		if (spec.base == 16 || !is_zero) {
465 			if (buf < end)
466 				*buf = '0';
467 			++buf;
468 		}
469 		if (spec.base == 16) {
470 			if (buf < end)
471 				*buf = ('X' | locase);
472 			++buf;
473 		}
474 	}
475 	/* zero or space padding */
476 	if (!(spec.flags & LEFT)) {
477 		char c = (spec.flags & ZEROPAD) ? '0' : ' ';
478 		while (--spec.field_width >= 0) {
479 			if (buf < end)
480 				*buf = c;
481 			++buf;
482 		}
483 	}
484 	/* hmm even more zero padding? */
485 	while (i <= --spec.precision) {
486 		if (buf < end)
487 			*buf = '0';
488 		++buf;
489 	}
490 	/* actual digits of result */
491 	while (--i >= 0) {
492 		if (buf < end)
493 			*buf = tmp[i];
494 		++buf;
495 	}
496 	/* trailing space padding */
497 	while (--spec.field_width >= 0) {
498 		if (buf < end)
499 			*buf = ' ';
500 		++buf;
501 	}
502 
503 	return buf;
504 }
505 
506 static noinline_for_stack
507 char *string(char *buf, char *end, const char *s, struct printf_spec spec)
508 {
509 	int len, i;
510 
511 	if ((unsigned long)s < PAGE_SIZE)
512 		s = "(null)";
513 
514 	len = strnlen(s, spec.precision);
515 
516 	if (!(spec.flags & LEFT)) {
517 		while (len < spec.field_width--) {
518 			if (buf < end)
519 				*buf = ' ';
520 			++buf;
521 		}
522 	}
523 	for (i = 0; i < len; ++i) {
524 		if (buf < end)
525 			*buf = *s;
526 		++buf; ++s;
527 	}
528 	while (len < spec.field_width--) {
529 		if (buf < end)
530 			*buf = ' ';
531 		++buf;
532 	}
533 
534 	return buf;
535 }
536 
537 static void widen(char *buf, char *end, unsigned len, unsigned spaces)
538 {
539 	size_t size;
540 	if (buf >= end)	/* nowhere to put anything */
541 		return;
542 	size = end - buf;
543 	if (size <= spaces) {
544 		memset(buf, ' ', size);
545 		return;
546 	}
547 	if (len) {
548 		if (len > size - spaces)
549 			len = size - spaces;
550 		memmove(buf + spaces, buf, len);
551 	}
552 	memset(buf, ' ', spaces);
553 }
554 
555 static noinline_for_stack
556 char *dentry_name(char *buf, char *end, const struct dentry *d, struct printf_spec spec,
557 		  const char *fmt)
558 {
559 	const char *array[4], *s;
560 	const struct dentry *p;
561 	int depth;
562 	int i, n;
563 
564 	switch (fmt[1]) {
565 		case '2': case '3': case '4':
566 			depth = fmt[1] - '0';
567 			break;
568 		default:
569 			depth = 1;
570 	}
571 
572 	rcu_read_lock();
573 	for (i = 0; i < depth; i++, d = p) {
574 		p = ACCESS_ONCE(d->d_parent);
575 		array[i] = ACCESS_ONCE(d->d_name.name);
576 		if (p == d) {
577 			if (i)
578 				array[i] = "";
579 			i++;
580 			break;
581 		}
582 	}
583 	s = array[--i];
584 	for (n = 0; n != spec.precision; n++, buf++) {
585 		char c = *s++;
586 		if (!c) {
587 			if (!i)
588 				break;
589 			c = '/';
590 			s = array[--i];
591 		}
592 		if (buf < end)
593 			*buf = c;
594 	}
595 	rcu_read_unlock();
596 	if (n < spec.field_width) {
597 		/* we want to pad the sucker */
598 		unsigned spaces = spec.field_width - n;
599 		if (!(spec.flags & LEFT)) {
600 			widen(buf - n, end, n, spaces);
601 			return buf + spaces;
602 		}
603 		while (spaces--) {
604 			if (buf < end)
605 				*buf = ' ';
606 			++buf;
607 		}
608 	}
609 	return buf;
610 }
611 
612 static noinline_for_stack
613 char *symbol_string(char *buf, char *end, void *ptr,
614 		    struct printf_spec spec, const char *fmt)
615 {
616 	unsigned long value;
617 #ifdef CONFIG_KALLSYMS
618 	char sym[KSYM_SYMBOL_LEN];
619 #endif
620 
621 	if (fmt[1] == 'R')
622 		ptr = __builtin_extract_return_addr(ptr);
623 	value = (unsigned long)ptr;
624 
625 #ifdef CONFIG_KALLSYMS
626 	if (*fmt == 'B')
627 		sprint_backtrace(sym, value);
628 	else if (*fmt != 'f' && *fmt != 's')
629 		sprint_symbol(sym, value);
630 	else
631 		sprint_symbol_no_offset(sym, value);
632 
633 	return string(buf, end, sym, spec);
634 #else
635 	spec.field_width = 2 * sizeof(void *);
636 	spec.flags |= SPECIAL | SMALL | ZEROPAD;
637 	spec.base = 16;
638 
639 	return number(buf, end, value, spec);
640 #endif
641 }
642 
643 static noinline_for_stack
644 char *resource_string(char *buf, char *end, struct resource *res,
645 		      struct printf_spec spec, const char *fmt)
646 {
647 #ifndef IO_RSRC_PRINTK_SIZE
648 #define IO_RSRC_PRINTK_SIZE	6
649 #endif
650 
651 #ifndef MEM_RSRC_PRINTK_SIZE
652 #define MEM_RSRC_PRINTK_SIZE	10
653 #endif
654 	static const struct printf_spec io_spec = {
655 		.base = 16,
656 		.field_width = IO_RSRC_PRINTK_SIZE,
657 		.precision = -1,
658 		.flags = SPECIAL | SMALL | ZEROPAD,
659 	};
660 	static const struct printf_spec mem_spec = {
661 		.base = 16,
662 		.field_width = MEM_RSRC_PRINTK_SIZE,
663 		.precision = -1,
664 		.flags = SPECIAL | SMALL | ZEROPAD,
665 	};
666 	static const struct printf_spec bus_spec = {
667 		.base = 16,
668 		.field_width = 2,
669 		.precision = -1,
670 		.flags = SMALL | ZEROPAD,
671 	};
672 	static const struct printf_spec dec_spec = {
673 		.base = 10,
674 		.precision = -1,
675 		.flags = 0,
676 	};
677 	static const struct printf_spec str_spec = {
678 		.field_width = -1,
679 		.precision = 10,
680 		.flags = LEFT,
681 	};
682 	static const struct printf_spec flag_spec = {
683 		.base = 16,
684 		.precision = -1,
685 		.flags = SPECIAL | SMALL,
686 	};
687 
688 	/* 32-bit res (sizeof==4): 10 chars in dec, 10 in hex ("0x" + 8)
689 	 * 64-bit res (sizeof==8): 20 chars in dec, 18 in hex ("0x" + 16) */
690 #define RSRC_BUF_SIZE		((2 * sizeof(resource_size_t)) + 4)
691 #define FLAG_BUF_SIZE		(2 * sizeof(res->flags))
692 #define DECODED_BUF_SIZE	sizeof("[mem - 64bit pref window disabled]")
693 #define RAW_BUF_SIZE		sizeof("[mem - flags 0x]")
694 	char sym[max(2*RSRC_BUF_SIZE + DECODED_BUF_SIZE,
695 		     2*RSRC_BUF_SIZE + FLAG_BUF_SIZE + RAW_BUF_SIZE)];
696 
697 	char *p = sym, *pend = sym + sizeof(sym);
698 	int decode = (fmt[0] == 'R') ? 1 : 0;
699 	const struct printf_spec *specp;
700 
701 	*p++ = '[';
702 	if (res->flags & IORESOURCE_IO) {
703 		p = string(p, pend, "io  ", str_spec);
704 		specp = &io_spec;
705 	} else if (res->flags & IORESOURCE_MEM) {
706 		p = string(p, pend, "mem ", str_spec);
707 		specp = &mem_spec;
708 	} else if (res->flags & IORESOURCE_IRQ) {
709 		p = string(p, pend, "irq ", str_spec);
710 		specp = &dec_spec;
711 	} else if (res->flags & IORESOURCE_DMA) {
712 		p = string(p, pend, "dma ", str_spec);
713 		specp = &dec_spec;
714 	} else if (res->flags & IORESOURCE_BUS) {
715 		p = string(p, pend, "bus ", str_spec);
716 		specp = &bus_spec;
717 	} else {
718 		p = string(p, pend, "??? ", str_spec);
719 		specp = &mem_spec;
720 		decode = 0;
721 	}
722 	if (decode && res->flags & IORESOURCE_UNSET) {
723 		p = string(p, pend, "size ", str_spec);
724 		p = number(p, pend, resource_size(res), *specp);
725 	} else {
726 		p = number(p, pend, res->start, *specp);
727 		if (res->start != res->end) {
728 			*p++ = '-';
729 			p = number(p, pend, res->end, *specp);
730 		}
731 	}
732 	if (decode) {
733 		if (res->flags & IORESOURCE_MEM_64)
734 			p = string(p, pend, " 64bit", str_spec);
735 		if (res->flags & IORESOURCE_PREFETCH)
736 			p = string(p, pend, " pref", str_spec);
737 		if (res->flags & IORESOURCE_WINDOW)
738 			p = string(p, pend, " window", str_spec);
739 		if (res->flags & IORESOURCE_DISABLED)
740 			p = string(p, pend, " disabled", str_spec);
741 	} else {
742 		p = string(p, pend, " flags ", str_spec);
743 		p = number(p, pend, res->flags, flag_spec);
744 	}
745 	*p++ = ']';
746 	*p = '\0';
747 
748 	return string(buf, end, sym, spec);
749 }
750 
751 static noinline_for_stack
752 char *hex_string(char *buf, char *end, u8 *addr, struct printf_spec spec,
753 		 const char *fmt)
754 {
755 	int i, len = 1;		/* if we pass '%ph[CDN]', field width remains
756 				   negative value, fallback to the default */
757 	char separator;
758 
759 	if (spec.field_width == 0)
760 		/* nothing to print */
761 		return buf;
762 
763 	if (ZERO_OR_NULL_PTR(addr))
764 		/* NULL pointer */
765 		return string(buf, end, NULL, spec);
766 
767 	switch (fmt[1]) {
768 	case 'C':
769 		separator = ':';
770 		break;
771 	case 'D':
772 		separator = '-';
773 		break;
774 	case 'N':
775 		separator = 0;
776 		break;
777 	default:
778 		separator = ' ';
779 		break;
780 	}
781 
782 	if (spec.field_width > 0)
783 		len = min_t(int, spec.field_width, 64);
784 
785 	for (i = 0; i < len && buf < end - 1; i++) {
786 		buf = hex_byte_pack(buf, addr[i]);
787 
788 		if (buf < end && separator && i != len - 1)
789 			*buf++ = separator;
790 	}
791 
792 	return buf;
793 }
794 
795 static noinline_for_stack
796 char *mac_address_string(char *buf, char *end, u8 *addr,
797 			 struct printf_spec spec, const char *fmt)
798 {
799 	char mac_addr[sizeof("xx:xx:xx:xx:xx:xx")];
800 	char *p = mac_addr;
801 	int i;
802 	char separator;
803 	bool reversed = false;
804 
805 	switch (fmt[1]) {
806 	case 'F':
807 		separator = '-';
808 		break;
809 
810 	case 'R':
811 		reversed = true;
812 		/* fall through */
813 
814 	default:
815 		separator = ':';
816 		break;
817 	}
818 
819 	for (i = 0; i < 6; i++) {
820 		if (reversed)
821 			p = hex_byte_pack(p, addr[5 - i]);
822 		else
823 			p = hex_byte_pack(p, addr[i]);
824 
825 		if (fmt[0] == 'M' && i != 5)
826 			*p++ = separator;
827 	}
828 	*p = '\0';
829 
830 	return string(buf, end, mac_addr, spec);
831 }
832 
833 static noinline_for_stack
834 char *ip4_string(char *p, const u8 *addr, const char *fmt)
835 {
836 	int i;
837 	bool leading_zeros = (fmt[0] == 'i');
838 	int index;
839 	int step;
840 
841 	switch (fmt[2]) {
842 	case 'h':
843 #ifdef __BIG_ENDIAN
844 		index = 0;
845 		step = 1;
846 #else
847 		index = 3;
848 		step = -1;
849 #endif
850 		break;
851 	case 'l':
852 		index = 3;
853 		step = -1;
854 		break;
855 	case 'n':
856 	case 'b':
857 	default:
858 		index = 0;
859 		step = 1;
860 		break;
861 	}
862 	for (i = 0; i < 4; i++) {
863 		char temp[3];	/* hold each IP quad in reverse order */
864 		int digits = put_dec_trunc8(temp, addr[index]) - temp;
865 		if (leading_zeros) {
866 			if (digits < 3)
867 				*p++ = '0';
868 			if (digits < 2)
869 				*p++ = '0';
870 		}
871 		/* reverse the digits in the quad */
872 		while (digits--)
873 			*p++ = temp[digits];
874 		if (i < 3)
875 			*p++ = '.';
876 		index += step;
877 	}
878 	*p = '\0';
879 
880 	return p;
881 }
882 
883 static noinline_for_stack
884 char *ip6_compressed_string(char *p, const char *addr)
885 {
886 	int i, j, range;
887 	unsigned char zerolength[8];
888 	int longest = 1;
889 	int colonpos = -1;
890 	u16 word;
891 	u8 hi, lo;
892 	bool needcolon = false;
893 	bool useIPv4;
894 	struct in6_addr in6;
895 
896 	memcpy(&in6, addr, sizeof(struct in6_addr));
897 
898 	useIPv4 = ipv6_addr_v4mapped(&in6) || ipv6_addr_is_isatap(&in6);
899 
900 	memset(zerolength, 0, sizeof(zerolength));
901 
902 	if (useIPv4)
903 		range = 6;
904 	else
905 		range = 8;
906 
907 	/* find position of longest 0 run */
908 	for (i = 0; i < range; i++) {
909 		for (j = i; j < range; j++) {
910 			if (in6.s6_addr16[j] != 0)
911 				break;
912 			zerolength[i]++;
913 		}
914 	}
915 	for (i = 0; i < range; i++) {
916 		if (zerolength[i] > longest) {
917 			longest = zerolength[i];
918 			colonpos = i;
919 		}
920 	}
921 	if (longest == 1)		/* don't compress a single 0 */
922 		colonpos = -1;
923 
924 	/* emit address */
925 	for (i = 0; i < range; i++) {
926 		if (i == colonpos) {
927 			if (needcolon || i == 0)
928 				*p++ = ':';
929 			*p++ = ':';
930 			needcolon = false;
931 			i += longest - 1;
932 			continue;
933 		}
934 		if (needcolon) {
935 			*p++ = ':';
936 			needcolon = false;
937 		}
938 		/* hex u16 without leading 0s */
939 		word = ntohs(in6.s6_addr16[i]);
940 		hi = word >> 8;
941 		lo = word & 0xff;
942 		if (hi) {
943 			if (hi > 0x0f)
944 				p = hex_byte_pack(p, hi);
945 			else
946 				*p++ = hex_asc_lo(hi);
947 			p = hex_byte_pack(p, lo);
948 		}
949 		else if (lo > 0x0f)
950 			p = hex_byte_pack(p, lo);
951 		else
952 			*p++ = hex_asc_lo(lo);
953 		needcolon = true;
954 	}
955 
956 	if (useIPv4) {
957 		if (needcolon)
958 			*p++ = ':';
959 		p = ip4_string(p, &in6.s6_addr[12], "I4");
960 	}
961 	*p = '\0';
962 
963 	return p;
964 }
965 
966 static noinline_for_stack
967 char *ip6_string(char *p, const char *addr, const char *fmt)
968 {
969 	int i;
970 
971 	for (i = 0; i < 8; i++) {
972 		p = hex_byte_pack(p, *addr++);
973 		p = hex_byte_pack(p, *addr++);
974 		if (fmt[0] == 'I' && i != 7)
975 			*p++ = ':';
976 	}
977 	*p = '\0';
978 
979 	return p;
980 }
981 
982 static noinline_for_stack
983 char *ip6_addr_string(char *buf, char *end, const u8 *addr,
984 		      struct printf_spec spec, const char *fmt)
985 {
986 	char ip6_addr[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255")];
987 
988 	if (fmt[0] == 'I' && fmt[2] == 'c')
989 		ip6_compressed_string(ip6_addr, addr);
990 	else
991 		ip6_string(ip6_addr, addr, fmt);
992 
993 	return string(buf, end, ip6_addr, spec);
994 }
995 
996 static noinline_for_stack
997 char *ip4_addr_string(char *buf, char *end, const u8 *addr,
998 		      struct printf_spec spec, const char *fmt)
999 {
1000 	char ip4_addr[sizeof("255.255.255.255")];
1001 
1002 	ip4_string(ip4_addr, addr, fmt);
1003 
1004 	return string(buf, end, ip4_addr, spec);
1005 }
1006 
1007 static noinline_for_stack
1008 char *ip6_addr_string_sa(char *buf, char *end, const struct sockaddr_in6 *sa,
1009 			 struct printf_spec spec, const char *fmt)
1010 {
1011 	bool have_p = false, have_s = false, have_f = false, have_c = false;
1012 	char ip6_addr[sizeof("[xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255]") +
1013 		      sizeof(":12345") + sizeof("/123456789") +
1014 		      sizeof("%1234567890")];
1015 	char *p = ip6_addr, *pend = ip6_addr + sizeof(ip6_addr);
1016 	const u8 *addr = (const u8 *) &sa->sin6_addr;
1017 	char fmt6[2] = { fmt[0], '6' };
1018 	u8 off = 0;
1019 
1020 	fmt++;
1021 	while (isalpha(*++fmt)) {
1022 		switch (*fmt) {
1023 		case 'p':
1024 			have_p = true;
1025 			break;
1026 		case 'f':
1027 			have_f = true;
1028 			break;
1029 		case 's':
1030 			have_s = true;
1031 			break;
1032 		case 'c':
1033 			have_c = true;
1034 			break;
1035 		}
1036 	}
1037 
1038 	if (have_p || have_s || have_f) {
1039 		*p = '[';
1040 		off = 1;
1041 	}
1042 
1043 	if (fmt6[0] == 'I' && have_c)
1044 		p = ip6_compressed_string(ip6_addr + off, addr);
1045 	else
1046 		p = ip6_string(ip6_addr + off, addr, fmt6);
1047 
1048 	if (have_p || have_s || have_f)
1049 		*p++ = ']';
1050 
1051 	if (have_p) {
1052 		*p++ = ':';
1053 		p = number(p, pend, ntohs(sa->sin6_port), spec);
1054 	}
1055 	if (have_f) {
1056 		*p++ = '/';
1057 		p = number(p, pend, ntohl(sa->sin6_flowinfo &
1058 					  IPV6_FLOWINFO_MASK), spec);
1059 	}
1060 	if (have_s) {
1061 		*p++ = '%';
1062 		p = number(p, pend, sa->sin6_scope_id, spec);
1063 	}
1064 	*p = '\0';
1065 
1066 	return string(buf, end, ip6_addr, spec);
1067 }
1068 
1069 static noinline_for_stack
1070 char *ip4_addr_string_sa(char *buf, char *end, const struct sockaddr_in *sa,
1071 			 struct printf_spec spec, const char *fmt)
1072 {
1073 	bool have_p = false;
1074 	char *p, ip4_addr[sizeof("255.255.255.255") + sizeof(":12345")];
1075 	char *pend = ip4_addr + sizeof(ip4_addr);
1076 	const u8 *addr = (const u8 *) &sa->sin_addr.s_addr;
1077 	char fmt4[3] = { fmt[0], '4', 0 };
1078 
1079 	fmt++;
1080 	while (isalpha(*++fmt)) {
1081 		switch (*fmt) {
1082 		case 'p':
1083 			have_p = true;
1084 			break;
1085 		case 'h':
1086 		case 'l':
1087 		case 'n':
1088 		case 'b':
1089 			fmt4[2] = *fmt;
1090 			break;
1091 		}
1092 	}
1093 
1094 	p = ip4_string(ip4_addr, addr, fmt4);
1095 	if (have_p) {
1096 		*p++ = ':';
1097 		p = number(p, pend, ntohs(sa->sin_port), spec);
1098 	}
1099 	*p = '\0';
1100 
1101 	return string(buf, end, ip4_addr, spec);
1102 }
1103 
1104 static noinline_for_stack
1105 char *uuid_string(char *buf, char *end, const u8 *addr,
1106 		  struct printf_spec spec, const char *fmt)
1107 {
1108 	char uuid[sizeof("xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx")];
1109 	char *p = uuid;
1110 	int i;
1111 	static const u8 be[16] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
1112 	static const u8 le[16] = {3,2,1,0,5,4,7,6,8,9,10,11,12,13,14,15};
1113 	const u8 *index = be;
1114 	bool uc = false;
1115 
1116 	switch (*(++fmt)) {
1117 	case 'L':
1118 		uc = true;		/* fall-through */
1119 	case 'l':
1120 		index = le;
1121 		break;
1122 	case 'B':
1123 		uc = true;
1124 		break;
1125 	}
1126 
1127 	for (i = 0; i < 16; i++) {
1128 		p = hex_byte_pack(p, addr[index[i]]);
1129 		switch (i) {
1130 		case 3:
1131 		case 5:
1132 		case 7:
1133 		case 9:
1134 			*p++ = '-';
1135 			break;
1136 		}
1137 	}
1138 
1139 	*p = 0;
1140 
1141 	if (uc) {
1142 		p = uuid;
1143 		do {
1144 			*p = toupper(*p);
1145 		} while (*(++p));
1146 	}
1147 
1148 	return string(buf, end, uuid, spec);
1149 }
1150 
1151 static
1152 char *netdev_feature_string(char *buf, char *end, const u8 *addr,
1153 		      struct printf_spec spec)
1154 {
1155 	spec.flags |= SPECIAL | SMALL | ZEROPAD;
1156 	if (spec.field_width == -1)
1157 		spec.field_width = 2 + 2 * sizeof(netdev_features_t);
1158 	spec.base = 16;
1159 
1160 	return number(buf, end, *(const netdev_features_t *)addr, spec);
1161 }
1162 
1163 static noinline_for_stack
1164 char *address_val(char *buf, char *end, const void *addr,
1165 		  struct printf_spec spec, const char *fmt)
1166 {
1167 	unsigned long long num;
1168 
1169 	spec.flags |= SPECIAL | SMALL | ZEROPAD;
1170 	spec.base = 16;
1171 
1172 	switch (fmt[1]) {
1173 	case 'd':
1174 		num = *(const dma_addr_t *)addr;
1175 		spec.field_width = sizeof(dma_addr_t) * 2 + 2;
1176 		break;
1177 	case 'p':
1178 	default:
1179 		num = *(const phys_addr_t *)addr;
1180 		spec.field_width = sizeof(phys_addr_t) * 2 + 2;
1181 		break;
1182 	}
1183 
1184 	return number(buf, end, num, spec);
1185 }
1186 
1187 int kptr_restrict __read_mostly;
1188 
1189 /*
1190  * Show a '%p' thing.  A kernel extension is that the '%p' is followed
1191  * by an extra set of alphanumeric characters that are extended format
1192  * specifiers.
1193  *
1194  * Right now we handle:
1195  *
1196  * - 'F' For symbolic function descriptor pointers with offset
1197  * - 'f' For simple symbolic function names without offset
1198  * - 'S' For symbolic direct pointers with offset
1199  * - 's' For symbolic direct pointers without offset
1200  * - '[FfSs]R' as above with __builtin_extract_return_addr() translation
1201  * - 'B' For backtraced symbolic direct pointers with offset
1202  * - 'R' For decoded struct resource, e.g., [mem 0x0-0x1f 64bit pref]
1203  * - 'r' For raw struct resource, e.g., [mem 0x0-0x1f flags 0x201]
1204  * - 'M' For a 6-byte MAC address, it prints the address in the
1205  *       usual colon-separated hex notation
1206  * - 'm' For a 6-byte MAC address, it prints the hex address without colons
1207  * - 'MF' For a 6-byte MAC FDDI address, it prints the address
1208  *       with a dash-separated hex notation
1209  * - '[mM]R' For a 6-byte MAC address, Reverse order (Bluetooth)
1210  * - 'I' [46] for IPv4/IPv6 addresses printed in the usual way
1211  *       IPv4 uses dot-separated decimal without leading 0's (1.2.3.4)
1212  *       IPv6 uses colon separated network-order 16 bit hex with leading 0's
1213  *       [S][pfs]
1214  *       Generic IPv4/IPv6 address (struct sockaddr *) that falls back to
1215  *       [4] or [6] and is able to print port [p], flowinfo [f], scope [s]
1216  * - 'i' [46] for 'raw' IPv4/IPv6 addresses
1217  *       IPv6 omits the colons (01020304...0f)
1218  *       IPv4 uses dot-separated decimal with leading 0's (010.123.045.006)
1219  *       [S][pfs]
1220  *       Generic IPv4/IPv6 address (struct sockaddr *) that falls back to
1221  *       [4] or [6] and is able to print port [p], flowinfo [f], scope [s]
1222  * - '[Ii][4S][hnbl]' IPv4 addresses in host, network, big or little endian order
1223  * - 'I[6S]c' for IPv6 addresses printed as specified by
1224  *       http://tools.ietf.org/html/rfc5952
1225  * - 'U' For a 16 byte UUID/GUID, it prints the UUID/GUID in the form
1226  *       "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
1227  *       Options for %pU are:
1228  *         b big endian lower case hex (default)
1229  *         B big endian UPPER case hex
1230  *         l little endian lower case hex
1231  *         L little endian UPPER case hex
1232  *           big endian output byte order is:
1233  *             [0][1][2][3]-[4][5]-[6][7]-[8][9]-[10][11][12][13][14][15]
1234  *           little endian output byte order is:
1235  *             [3][2][1][0]-[5][4]-[7][6]-[8][9]-[10][11][12][13][14][15]
1236  * - 'V' For a struct va_format which contains a format string * and va_list *,
1237  *       call vsnprintf(->format, *->va_list).
1238  *       Implements a "recursive vsnprintf".
1239  *       Do not use this feature without some mechanism to verify the
1240  *       correctness of the format string and va_list arguments.
1241  * - 'K' For a kernel pointer that should be hidden from unprivileged users
1242  * - 'NF' For a netdev_features_t
1243  * - 'h[CDN]' For a variable-length buffer, it prints it as a hex string with
1244  *            a certain separator (' ' by default):
1245  *              C colon
1246  *              D dash
1247  *              N no separator
1248  *            The maximum supported length is 64 bytes of the input. Consider
1249  *            to use print_hex_dump() for the larger input.
1250  * - 'a[pd]' For address types [p] phys_addr_t, [d] dma_addr_t and derivatives
1251  *           (default assumed to be phys_addr_t, passed by reference)
1252  * - 'd[234]' For a dentry name (optionally 2-4 last components)
1253  * - 'D[234]' Same as 'd' but for a struct file
1254  *
1255  * Note: The difference between 'S' and 'F' is that on ia64 and ppc64
1256  * function pointers are really function descriptors, which contain a
1257  * pointer to the real address.
1258  */
1259 static noinline_for_stack
1260 char *pointer(const char *fmt, char *buf, char *end, void *ptr,
1261 	      struct printf_spec spec)
1262 {
1263 	int default_width = 2 * sizeof(void *) + (spec.flags & SPECIAL ? 2 : 0);
1264 
1265 	if (!ptr && *fmt != 'K') {
1266 		/*
1267 		 * Print (null) with the same width as a pointer so it makes
1268 		 * tabular output look nice.
1269 		 */
1270 		if (spec.field_width == -1)
1271 			spec.field_width = default_width;
1272 		return string(buf, end, "(null)", spec);
1273 	}
1274 
1275 	switch (*fmt) {
1276 	case 'F':
1277 	case 'f':
1278 		ptr = dereference_function_descriptor(ptr);
1279 		/* Fallthrough */
1280 	case 'S':
1281 	case 's':
1282 	case 'B':
1283 		return symbol_string(buf, end, ptr, spec, fmt);
1284 	case 'R':
1285 	case 'r':
1286 		return resource_string(buf, end, ptr, spec, fmt);
1287 	case 'h':
1288 		return hex_string(buf, end, ptr, spec, fmt);
1289 	case 'M':			/* Colon separated: 00:01:02:03:04:05 */
1290 	case 'm':			/* Contiguous: 000102030405 */
1291 					/* [mM]F (FDDI) */
1292 					/* [mM]R (Reverse order; Bluetooth) */
1293 		return mac_address_string(buf, end, ptr, spec, fmt);
1294 	case 'I':			/* Formatted IP supported
1295 					 * 4:	1.2.3.4
1296 					 * 6:	0001:0203:...:0708
1297 					 * 6c:	1::708 or 1::1.2.3.4
1298 					 */
1299 	case 'i':			/* Contiguous:
1300 					 * 4:	001.002.003.004
1301 					 * 6:   000102...0f
1302 					 */
1303 		switch (fmt[1]) {
1304 		case '6':
1305 			return ip6_addr_string(buf, end, ptr, spec, fmt);
1306 		case '4':
1307 			return ip4_addr_string(buf, end, ptr, spec, fmt);
1308 		case 'S': {
1309 			const union {
1310 				struct sockaddr		raw;
1311 				struct sockaddr_in	v4;
1312 				struct sockaddr_in6	v6;
1313 			} *sa = ptr;
1314 
1315 			switch (sa->raw.sa_family) {
1316 			case AF_INET:
1317 				return ip4_addr_string_sa(buf, end, &sa->v4, spec, fmt);
1318 			case AF_INET6:
1319 				return ip6_addr_string_sa(buf, end, &sa->v6, spec, fmt);
1320 			default:
1321 				return string(buf, end, "(invalid address)", spec);
1322 			}}
1323 		}
1324 		break;
1325 	case 'U':
1326 		return uuid_string(buf, end, ptr, spec, fmt);
1327 	case 'V':
1328 		{
1329 			va_list va;
1330 
1331 			va_copy(va, *((struct va_format *)ptr)->va);
1332 			buf += vsnprintf(buf, end > buf ? end - buf : 0,
1333 					 ((struct va_format *)ptr)->fmt, va);
1334 			va_end(va);
1335 			return buf;
1336 		}
1337 	case 'K':
1338 		/*
1339 		 * %pK cannot be used in IRQ context because its test
1340 		 * for CAP_SYSLOG would be meaningless.
1341 		 */
1342 		if (kptr_restrict && (in_irq() || in_serving_softirq() ||
1343 				      in_nmi())) {
1344 			if (spec.field_width == -1)
1345 				spec.field_width = default_width;
1346 			return string(buf, end, "pK-error", spec);
1347 		}
1348 
1349 		switch (kptr_restrict) {
1350 		case 0:
1351 			/* Always print %pK values */
1352 			break;
1353 		case 1: {
1354 			/*
1355 			 * Only print the real pointer value if the current
1356 			 * process has CAP_SYSLOG and is running with the
1357 			 * same credentials it started with. This is because
1358 			 * access to files is checked at open() time, but %pK
1359 			 * checks permission at read() time. We don't want to
1360 			 * leak pointer values if a binary opens a file using
1361 			 * %pK and then elevates privileges before reading it.
1362 			 */
1363 			const struct cred *cred = current_cred();
1364 
1365 			if (!has_capability_noaudit(current, CAP_SYSLOG) ||
1366 			    !uid_eq(cred->euid, cred->uid) ||
1367 			    !gid_eq(cred->egid, cred->gid))
1368 				ptr = NULL;
1369 			break;
1370 		}
1371 		case 2:
1372 		default:
1373 			/* Always print 0's for %pK */
1374 			ptr = NULL;
1375 			break;
1376 		}
1377 		break;
1378 
1379 	case 'N':
1380 		switch (fmt[1]) {
1381 		case 'F':
1382 			return netdev_feature_string(buf, end, ptr, spec);
1383 		}
1384 		break;
1385 	case 'a':
1386 		return address_val(buf, end, ptr, spec, fmt);
1387 	case 'd':
1388 		return dentry_name(buf, end, ptr, spec, fmt);
1389 	case 'D':
1390 		return dentry_name(buf, end,
1391 				   ((const struct file *)ptr)->f_path.dentry,
1392 				   spec, fmt);
1393 	}
1394 	spec.flags |= SMALL;
1395 	if (spec.field_width == -1) {
1396 		spec.field_width = default_width;
1397 		spec.flags |= ZEROPAD;
1398 	}
1399 	spec.base = 16;
1400 
1401 	return number(buf, end, (unsigned long) ptr, spec);
1402 }
1403 
1404 /*
1405  * Helper function to decode printf style format.
1406  * Each call decode a token from the format and return the
1407  * number of characters read (or likely the delta where it wants
1408  * to go on the next call).
1409  * The decoded token is returned through the parameters
1410  *
1411  * 'h', 'l', or 'L' for integer fields
1412  * 'z' support added 23/7/1999 S.H.
1413  * 'z' changed to 'Z' --davidm 1/25/99
1414  * 't' added for ptrdiff_t
1415  *
1416  * @fmt: the format string
1417  * @type of the token returned
1418  * @flags: various flags such as +, -, # tokens..
1419  * @field_width: overwritten width
1420  * @base: base of the number (octal, hex, ...)
1421  * @precision: precision of a number
1422  * @qualifier: qualifier of a number (long, size_t, ...)
1423  */
1424 static noinline_for_stack
1425 int format_decode(const char *fmt, struct printf_spec *spec)
1426 {
1427 	const char *start = fmt;
1428 
1429 	/* we finished early by reading the field width */
1430 	if (spec->type == FORMAT_TYPE_WIDTH) {
1431 		if (spec->field_width < 0) {
1432 			spec->field_width = -spec->field_width;
1433 			spec->flags |= LEFT;
1434 		}
1435 		spec->type = FORMAT_TYPE_NONE;
1436 		goto precision;
1437 	}
1438 
1439 	/* we finished early by reading the precision */
1440 	if (spec->type == FORMAT_TYPE_PRECISION) {
1441 		if (spec->precision < 0)
1442 			spec->precision = 0;
1443 
1444 		spec->type = FORMAT_TYPE_NONE;
1445 		goto qualifier;
1446 	}
1447 
1448 	/* By default */
1449 	spec->type = FORMAT_TYPE_NONE;
1450 
1451 	for (; *fmt ; ++fmt) {
1452 		if (*fmt == '%')
1453 			break;
1454 	}
1455 
1456 	/* Return the current non-format string */
1457 	if (fmt != start || !*fmt)
1458 		return fmt - start;
1459 
1460 	/* Process flags */
1461 	spec->flags = 0;
1462 
1463 	while (1) { /* this also skips first '%' */
1464 		bool found = true;
1465 
1466 		++fmt;
1467 
1468 		switch (*fmt) {
1469 		case '-': spec->flags |= LEFT;    break;
1470 		case '+': spec->flags |= PLUS;    break;
1471 		case ' ': spec->flags |= SPACE;   break;
1472 		case '#': spec->flags |= SPECIAL; break;
1473 		case '0': spec->flags |= ZEROPAD; break;
1474 		default:  found = false;
1475 		}
1476 
1477 		if (!found)
1478 			break;
1479 	}
1480 
1481 	/* get field width */
1482 	spec->field_width = -1;
1483 
1484 	if (isdigit(*fmt))
1485 		spec->field_width = skip_atoi(&fmt);
1486 	else if (*fmt == '*') {
1487 		/* it's the next argument */
1488 		spec->type = FORMAT_TYPE_WIDTH;
1489 		return ++fmt - start;
1490 	}
1491 
1492 precision:
1493 	/* get the precision */
1494 	spec->precision = -1;
1495 	if (*fmt == '.') {
1496 		++fmt;
1497 		if (isdigit(*fmt)) {
1498 			spec->precision = skip_atoi(&fmt);
1499 			if (spec->precision < 0)
1500 				spec->precision = 0;
1501 		} else if (*fmt == '*') {
1502 			/* it's the next argument */
1503 			spec->type = FORMAT_TYPE_PRECISION;
1504 			return ++fmt - start;
1505 		}
1506 	}
1507 
1508 qualifier:
1509 	/* get the conversion qualifier */
1510 	spec->qualifier = -1;
1511 	if (*fmt == 'h' || _tolower(*fmt) == 'l' ||
1512 	    _tolower(*fmt) == 'z' || *fmt == 't') {
1513 		spec->qualifier = *fmt++;
1514 		if (unlikely(spec->qualifier == *fmt)) {
1515 			if (spec->qualifier == 'l') {
1516 				spec->qualifier = 'L';
1517 				++fmt;
1518 			} else if (spec->qualifier == 'h') {
1519 				spec->qualifier = 'H';
1520 				++fmt;
1521 			}
1522 		}
1523 	}
1524 
1525 	/* default base */
1526 	spec->base = 10;
1527 	switch (*fmt) {
1528 	case 'c':
1529 		spec->type = FORMAT_TYPE_CHAR;
1530 		return ++fmt - start;
1531 
1532 	case 's':
1533 		spec->type = FORMAT_TYPE_STR;
1534 		return ++fmt - start;
1535 
1536 	case 'p':
1537 		spec->type = FORMAT_TYPE_PTR;
1538 		return fmt - start;
1539 		/* skip alnum */
1540 
1541 	case 'n':
1542 		spec->type = FORMAT_TYPE_NRCHARS;
1543 		return ++fmt - start;
1544 
1545 	case '%':
1546 		spec->type = FORMAT_TYPE_PERCENT_CHAR;
1547 		return ++fmt - start;
1548 
1549 	/* integer number formats - set up the flags and "break" */
1550 	case 'o':
1551 		spec->base = 8;
1552 		break;
1553 
1554 	case 'x':
1555 		spec->flags |= SMALL;
1556 
1557 	case 'X':
1558 		spec->base = 16;
1559 		break;
1560 
1561 	case 'd':
1562 	case 'i':
1563 		spec->flags |= SIGN;
1564 	case 'u':
1565 		break;
1566 
1567 	default:
1568 		spec->type = FORMAT_TYPE_INVALID;
1569 		return fmt - start;
1570 	}
1571 
1572 	if (spec->qualifier == 'L')
1573 		spec->type = FORMAT_TYPE_LONG_LONG;
1574 	else if (spec->qualifier == 'l') {
1575 		if (spec->flags & SIGN)
1576 			spec->type = FORMAT_TYPE_LONG;
1577 		else
1578 			spec->type = FORMAT_TYPE_ULONG;
1579 	} else if (_tolower(spec->qualifier) == 'z') {
1580 		spec->type = FORMAT_TYPE_SIZE_T;
1581 	} else if (spec->qualifier == 't') {
1582 		spec->type = FORMAT_TYPE_PTRDIFF;
1583 	} else if (spec->qualifier == 'H') {
1584 		if (spec->flags & SIGN)
1585 			spec->type = FORMAT_TYPE_BYTE;
1586 		else
1587 			spec->type = FORMAT_TYPE_UBYTE;
1588 	} else if (spec->qualifier == 'h') {
1589 		if (spec->flags & SIGN)
1590 			spec->type = FORMAT_TYPE_SHORT;
1591 		else
1592 			spec->type = FORMAT_TYPE_USHORT;
1593 	} else {
1594 		if (spec->flags & SIGN)
1595 			spec->type = FORMAT_TYPE_INT;
1596 		else
1597 			spec->type = FORMAT_TYPE_UINT;
1598 	}
1599 
1600 	return ++fmt - start;
1601 }
1602 
1603 /**
1604  * vsnprintf - Format a string and place it in a buffer
1605  * @buf: The buffer to place the result into
1606  * @size: The size of the buffer, including the trailing null space
1607  * @fmt: The format string to use
1608  * @args: Arguments for the format string
1609  *
1610  * This function follows C99 vsnprintf, but has some extensions:
1611  * %pS output the name of a text symbol with offset
1612  * %ps output the name of a text symbol without offset
1613  * %pF output the name of a function pointer with its offset
1614  * %pf output the name of a function pointer without its offset
1615  * %pB output the name of a backtrace symbol with its offset
1616  * %pR output the address range in a struct resource with decoded flags
1617  * %pr output the address range in a struct resource with raw flags
1618  * %pM output a 6-byte MAC address with colons
1619  * %pMR output a 6-byte MAC address with colons in reversed order
1620  * %pMF output a 6-byte MAC address with dashes
1621  * %pm output a 6-byte MAC address without colons
1622  * %pmR output a 6-byte MAC address without colons in reversed order
1623  * %pI4 print an IPv4 address without leading zeros
1624  * %pi4 print an IPv4 address with leading zeros
1625  * %pI6 print an IPv6 address with colons
1626  * %pi6 print an IPv6 address without colons
1627  * %pI6c print an IPv6 address as specified by RFC 5952
1628  * %pIS depending on sa_family of 'struct sockaddr *' print IPv4/IPv6 address
1629  * %piS depending on sa_family of 'struct sockaddr *' print IPv4/IPv6 address
1630  * %pU[bBlL] print a UUID/GUID in big or little endian using lower or upper
1631  *   case.
1632  * %*ph[CDN] a variable-length hex string with a separator (supports up to 64
1633  *           bytes of the input)
1634  * %n is ignored
1635  *
1636  * ** Please update Documentation/printk-formats.txt when making changes **
1637  *
1638  * The return value is the number of characters which would
1639  * be generated for the given input, excluding the trailing
1640  * '\0', as per ISO C99. If you want to have the exact
1641  * number of characters written into @buf as return value
1642  * (not including the trailing '\0'), use vscnprintf(). If the
1643  * return is greater than or equal to @size, the resulting
1644  * string is truncated.
1645  *
1646  * If you're not already dealing with a va_list consider using snprintf().
1647  */
1648 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
1649 {
1650 	unsigned long long num;
1651 	char *str, *end;
1652 	struct printf_spec spec = {0};
1653 
1654 	/* Reject out-of-range values early.  Large positive sizes are
1655 	   used for unknown buffer sizes. */
1656 	if (WARN_ON_ONCE((int) size < 0))
1657 		return 0;
1658 
1659 	str = buf;
1660 	end = buf + size;
1661 
1662 	/* Make sure end is always >= buf */
1663 	if (end < buf) {
1664 		end = ((void *)-1);
1665 		size = end - buf;
1666 	}
1667 
1668 	while (*fmt) {
1669 		const char *old_fmt = fmt;
1670 		int read = format_decode(fmt, &spec);
1671 
1672 		fmt += read;
1673 
1674 		switch (spec.type) {
1675 		case FORMAT_TYPE_NONE: {
1676 			int copy = read;
1677 			if (str < end) {
1678 				if (copy > end - str)
1679 					copy = end - str;
1680 				memcpy(str, old_fmt, copy);
1681 			}
1682 			str += read;
1683 			break;
1684 		}
1685 
1686 		case FORMAT_TYPE_WIDTH:
1687 			spec.field_width = va_arg(args, int);
1688 			break;
1689 
1690 		case FORMAT_TYPE_PRECISION:
1691 			spec.precision = va_arg(args, int);
1692 			break;
1693 
1694 		case FORMAT_TYPE_CHAR: {
1695 			char c;
1696 
1697 			if (!(spec.flags & LEFT)) {
1698 				while (--spec.field_width > 0) {
1699 					if (str < end)
1700 						*str = ' ';
1701 					++str;
1702 
1703 				}
1704 			}
1705 			c = (unsigned char) va_arg(args, int);
1706 			if (str < end)
1707 				*str = c;
1708 			++str;
1709 			while (--spec.field_width > 0) {
1710 				if (str < end)
1711 					*str = ' ';
1712 				++str;
1713 			}
1714 			break;
1715 		}
1716 
1717 		case FORMAT_TYPE_STR:
1718 			str = string(str, end, va_arg(args, char *), spec);
1719 			break;
1720 
1721 		case FORMAT_TYPE_PTR:
1722 			str = pointer(fmt+1, str, end, va_arg(args, void *),
1723 				      spec);
1724 			while (isalnum(*fmt))
1725 				fmt++;
1726 			break;
1727 
1728 		case FORMAT_TYPE_PERCENT_CHAR:
1729 			if (str < end)
1730 				*str = '%';
1731 			++str;
1732 			break;
1733 
1734 		case FORMAT_TYPE_INVALID:
1735 			if (str < end)
1736 				*str = '%';
1737 			++str;
1738 			break;
1739 
1740 		case FORMAT_TYPE_NRCHARS: {
1741 			/*
1742 			 * Since %n poses a greater security risk than
1743 			 * utility, ignore %n and skip its argument.
1744 			 */
1745 			void *skip_arg;
1746 
1747 			WARN_ONCE(1, "Please remove ignored %%n in '%s'\n",
1748 					old_fmt);
1749 
1750 			skip_arg = va_arg(args, void *);
1751 			break;
1752 		}
1753 
1754 		default:
1755 			switch (spec.type) {
1756 			case FORMAT_TYPE_LONG_LONG:
1757 				num = va_arg(args, long long);
1758 				break;
1759 			case FORMAT_TYPE_ULONG:
1760 				num = va_arg(args, unsigned long);
1761 				break;
1762 			case FORMAT_TYPE_LONG:
1763 				num = va_arg(args, long);
1764 				break;
1765 			case FORMAT_TYPE_SIZE_T:
1766 				if (spec.flags & SIGN)
1767 					num = va_arg(args, ssize_t);
1768 				else
1769 					num = va_arg(args, size_t);
1770 				break;
1771 			case FORMAT_TYPE_PTRDIFF:
1772 				num = va_arg(args, ptrdiff_t);
1773 				break;
1774 			case FORMAT_TYPE_UBYTE:
1775 				num = (unsigned char) va_arg(args, int);
1776 				break;
1777 			case FORMAT_TYPE_BYTE:
1778 				num = (signed char) va_arg(args, int);
1779 				break;
1780 			case FORMAT_TYPE_USHORT:
1781 				num = (unsigned short) va_arg(args, int);
1782 				break;
1783 			case FORMAT_TYPE_SHORT:
1784 				num = (short) va_arg(args, int);
1785 				break;
1786 			case FORMAT_TYPE_INT:
1787 				num = (int) va_arg(args, int);
1788 				break;
1789 			default:
1790 				num = va_arg(args, unsigned int);
1791 			}
1792 
1793 			str = number(str, end, num, spec);
1794 		}
1795 	}
1796 
1797 	if (size > 0) {
1798 		if (str < end)
1799 			*str = '\0';
1800 		else
1801 			end[-1] = '\0';
1802 	}
1803 
1804 	/* the trailing null byte doesn't count towards the total */
1805 	return str-buf;
1806 
1807 }
1808 EXPORT_SYMBOL(vsnprintf);
1809 
1810 /**
1811  * vscnprintf - Format a string and place it in a buffer
1812  * @buf: The buffer to place the result into
1813  * @size: The size of the buffer, including the trailing null space
1814  * @fmt: The format string to use
1815  * @args: Arguments for the format string
1816  *
1817  * The return value is the number of characters which have been written into
1818  * the @buf not including the trailing '\0'. If @size is == 0 the function
1819  * returns 0.
1820  *
1821  * If you're not already dealing with a va_list consider using scnprintf().
1822  *
1823  * See the vsnprintf() documentation for format string extensions over C99.
1824  */
1825 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
1826 {
1827 	int i;
1828 
1829 	i = vsnprintf(buf, size, fmt, args);
1830 
1831 	if (likely(i < size))
1832 		return i;
1833 	if (size != 0)
1834 		return size - 1;
1835 	return 0;
1836 }
1837 EXPORT_SYMBOL(vscnprintf);
1838 
1839 /**
1840  * snprintf - Format a string and place it in a buffer
1841  * @buf: The buffer to place the result into
1842  * @size: The size of the buffer, including the trailing null space
1843  * @fmt: The format string to use
1844  * @...: Arguments for the format string
1845  *
1846  * The return value is the number of characters which would be
1847  * generated for the given input, excluding the trailing null,
1848  * as per ISO C99.  If the return is greater than or equal to
1849  * @size, the resulting string is truncated.
1850  *
1851  * See the vsnprintf() documentation for format string extensions over C99.
1852  */
1853 int snprintf(char *buf, size_t size, const char *fmt, ...)
1854 {
1855 	va_list args;
1856 	int i;
1857 
1858 	va_start(args, fmt);
1859 	i = vsnprintf(buf, size, fmt, args);
1860 	va_end(args);
1861 
1862 	return i;
1863 }
1864 EXPORT_SYMBOL(snprintf);
1865 
1866 /**
1867  * scnprintf - Format a string and place it in a buffer
1868  * @buf: The buffer to place the result into
1869  * @size: The size of the buffer, including the trailing null space
1870  * @fmt: The format string to use
1871  * @...: Arguments for the format string
1872  *
1873  * The return value is the number of characters written into @buf not including
1874  * the trailing '\0'. If @size is == 0 the function returns 0.
1875  */
1876 
1877 int scnprintf(char *buf, size_t size, const char *fmt, ...)
1878 {
1879 	va_list args;
1880 	int i;
1881 
1882 	va_start(args, fmt);
1883 	i = vscnprintf(buf, size, fmt, args);
1884 	va_end(args);
1885 
1886 	return i;
1887 }
1888 EXPORT_SYMBOL(scnprintf);
1889 
1890 /**
1891  * vsprintf - Format a string and place it in a buffer
1892  * @buf: The buffer to place the result into
1893  * @fmt: The format string to use
1894  * @args: Arguments for the format string
1895  *
1896  * The function returns the number of characters written
1897  * into @buf. Use vsnprintf() or vscnprintf() in order to avoid
1898  * buffer overflows.
1899  *
1900  * If you're not already dealing with a va_list consider using sprintf().
1901  *
1902  * See the vsnprintf() documentation for format string extensions over C99.
1903  */
1904 int vsprintf(char *buf, const char *fmt, va_list args)
1905 {
1906 	return vsnprintf(buf, INT_MAX, fmt, args);
1907 }
1908 EXPORT_SYMBOL(vsprintf);
1909 
1910 /**
1911  * sprintf - Format a string and place it in a buffer
1912  * @buf: The buffer to place the result into
1913  * @fmt: The format string to use
1914  * @...: Arguments for the format string
1915  *
1916  * The function returns the number of characters written
1917  * into @buf. Use snprintf() or scnprintf() in order to avoid
1918  * buffer overflows.
1919  *
1920  * See the vsnprintf() documentation for format string extensions over C99.
1921  */
1922 int sprintf(char *buf, const char *fmt, ...)
1923 {
1924 	va_list args;
1925 	int i;
1926 
1927 	va_start(args, fmt);
1928 	i = vsnprintf(buf, INT_MAX, fmt, args);
1929 	va_end(args);
1930 
1931 	return i;
1932 }
1933 EXPORT_SYMBOL(sprintf);
1934 
1935 #ifdef CONFIG_BINARY_PRINTF
1936 /*
1937  * bprintf service:
1938  * vbin_printf() - VA arguments to binary data
1939  * bstr_printf() - Binary data to text string
1940  */
1941 
1942 /**
1943  * vbin_printf - Parse a format string and place args' binary value in a buffer
1944  * @bin_buf: The buffer to place args' binary value
1945  * @size: The size of the buffer(by words(32bits), not characters)
1946  * @fmt: The format string to use
1947  * @args: Arguments for the format string
1948  *
1949  * The format follows C99 vsnprintf, except %n is ignored, and its argument
1950  * is skiped.
1951  *
1952  * The return value is the number of words(32bits) which would be generated for
1953  * the given input.
1954  *
1955  * NOTE:
1956  * If the return value is greater than @size, the resulting bin_buf is NOT
1957  * valid for bstr_printf().
1958  */
1959 int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args)
1960 {
1961 	struct printf_spec spec = {0};
1962 	char *str, *end;
1963 
1964 	str = (char *)bin_buf;
1965 	end = (char *)(bin_buf + size);
1966 
1967 #define save_arg(type)							\
1968 do {									\
1969 	if (sizeof(type) == 8) {					\
1970 		unsigned long long value;				\
1971 		str = PTR_ALIGN(str, sizeof(u32));			\
1972 		value = va_arg(args, unsigned long long);		\
1973 		if (str + sizeof(type) <= end) {			\
1974 			*(u32 *)str = *(u32 *)&value;			\
1975 			*(u32 *)(str + 4) = *((u32 *)&value + 1);	\
1976 		}							\
1977 	} else {							\
1978 		unsigned long value;					\
1979 		str = PTR_ALIGN(str, sizeof(type));			\
1980 		value = va_arg(args, int);				\
1981 		if (str + sizeof(type) <= end)				\
1982 			*(typeof(type) *)str = (type)value;		\
1983 	}								\
1984 	str += sizeof(type);						\
1985 } while (0)
1986 
1987 	while (*fmt) {
1988 		int read = format_decode(fmt, &spec);
1989 
1990 		fmt += read;
1991 
1992 		switch (spec.type) {
1993 		case FORMAT_TYPE_NONE:
1994 		case FORMAT_TYPE_INVALID:
1995 		case FORMAT_TYPE_PERCENT_CHAR:
1996 			break;
1997 
1998 		case FORMAT_TYPE_WIDTH:
1999 		case FORMAT_TYPE_PRECISION:
2000 			save_arg(int);
2001 			break;
2002 
2003 		case FORMAT_TYPE_CHAR:
2004 			save_arg(char);
2005 			break;
2006 
2007 		case FORMAT_TYPE_STR: {
2008 			const char *save_str = va_arg(args, char *);
2009 			size_t len;
2010 
2011 			if ((unsigned long)save_str > (unsigned long)-PAGE_SIZE
2012 					|| (unsigned long)save_str < PAGE_SIZE)
2013 				save_str = "(null)";
2014 			len = strlen(save_str) + 1;
2015 			if (str + len < end)
2016 				memcpy(str, save_str, len);
2017 			str += len;
2018 			break;
2019 		}
2020 
2021 		case FORMAT_TYPE_PTR:
2022 			save_arg(void *);
2023 			/* skip all alphanumeric pointer suffixes */
2024 			while (isalnum(*fmt))
2025 				fmt++;
2026 			break;
2027 
2028 		case FORMAT_TYPE_NRCHARS: {
2029 			/* skip %n 's argument */
2030 			u8 qualifier = spec.qualifier;
2031 			void *skip_arg;
2032 			if (qualifier == 'l')
2033 				skip_arg = va_arg(args, long *);
2034 			else if (_tolower(qualifier) == 'z')
2035 				skip_arg = va_arg(args, size_t *);
2036 			else
2037 				skip_arg = va_arg(args, int *);
2038 			break;
2039 		}
2040 
2041 		default:
2042 			switch (spec.type) {
2043 
2044 			case FORMAT_TYPE_LONG_LONG:
2045 				save_arg(long long);
2046 				break;
2047 			case FORMAT_TYPE_ULONG:
2048 			case FORMAT_TYPE_LONG:
2049 				save_arg(unsigned long);
2050 				break;
2051 			case FORMAT_TYPE_SIZE_T:
2052 				save_arg(size_t);
2053 				break;
2054 			case FORMAT_TYPE_PTRDIFF:
2055 				save_arg(ptrdiff_t);
2056 				break;
2057 			case FORMAT_TYPE_UBYTE:
2058 			case FORMAT_TYPE_BYTE:
2059 				save_arg(char);
2060 				break;
2061 			case FORMAT_TYPE_USHORT:
2062 			case FORMAT_TYPE_SHORT:
2063 				save_arg(short);
2064 				break;
2065 			default:
2066 				save_arg(int);
2067 			}
2068 		}
2069 	}
2070 
2071 	return (u32 *)(PTR_ALIGN(str, sizeof(u32))) - bin_buf;
2072 #undef save_arg
2073 }
2074 EXPORT_SYMBOL_GPL(vbin_printf);
2075 
2076 /**
2077  * bstr_printf - Format a string from binary arguments and place it in a buffer
2078  * @buf: The buffer to place the result into
2079  * @size: The size of the buffer, including the trailing null space
2080  * @fmt: The format string to use
2081  * @bin_buf: Binary arguments for the format string
2082  *
2083  * This function like C99 vsnprintf, but the difference is that vsnprintf gets
2084  * arguments from stack, and bstr_printf gets arguments from @bin_buf which is
2085  * a binary buffer that generated by vbin_printf.
2086  *
2087  * The format follows C99 vsnprintf, but has some extensions:
2088  *  see vsnprintf comment for details.
2089  *
2090  * The return value is the number of characters which would
2091  * be generated for the given input, excluding the trailing
2092  * '\0', as per ISO C99. If you want to have the exact
2093  * number of characters written into @buf as return value
2094  * (not including the trailing '\0'), use vscnprintf(). If the
2095  * return is greater than or equal to @size, the resulting
2096  * string is truncated.
2097  */
2098 int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf)
2099 {
2100 	struct printf_spec spec = {0};
2101 	char *str, *end;
2102 	const char *args = (const char *)bin_buf;
2103 
2104 	if (WARN_ON_ONCE((int) size < 0))
2105 		return 0;
2106 
2107 	str = buf;
2108 	end = buf + size;
2109 
2110 #define get_arg(type)							\
2111 ({									\
2112 	typeof(type) value;						\
2113 	if (sizeof(type) == 8) {					\
2114 		args = PTR_ALIGN(args, sizeof(u32));			\
2115 		*(u32 *)&value = *(u32 *)args;				\
2116 		*((u32 *)&value + 1) = *(u32 *)(args + 4);		\
2117 	} else {							\
2118 		args = PTR_ALIGN(args, sizeof(type));			\
2119 		value = *(typeof(type) *)args;				\
2120 	}								\
2121 	args += sizeof(type);						\
2122 	value;								\
2123 })
2124 
2125 	/* Make sure end is always >= buf */
2126 	if (end < buf) {
2127 		end = ((void *)-1);
2128 		size = end - buf;
2129 	}
2130 
2131 	while (*fmt) {
2132 		const char *old_fmt = fmt;
2133 		int read = format_decode(fmt, &spec);
2134 
2135 		fmt += read;
2136 
2137 		switch (spec.type) {
2138 		case FORMAT_TYPE_NONE: {
2139 			int copy = read;
2140 			if (str < end) {
2141 				if (copy > end - str)
2142 					copy = end - str;
2143 				memcpy(str, old_fmt, copy);
2144 			}
2145 			str += read;
2146 			break;
2147 		}
2148 
2149 		case FORMAT_TYPE_WIDTH:
2150 			spec.field_width = get_arg(int);
2151 			break;
2152 
2153 		case FORMAT_TYPE_PRECISION:
2154 			spec.precision = get_arg(int);
2155 			break;
2156 
2157 		case FORMAT_TYPE_CHAR: {
2158 			char c;
2159 
2160 			if (!(spec.flags & LEFT)) {
2161 				while (--spec.field_width > 0) {
2162 					if (str < end)
2163 						*str = ' ';
2164 					++str;
2165 				}
2166 			}
2167 			c = (unsigned char) get_arg(char);
2168 			if (str < end)
2169 				*str = c;
2170 			++str;
2171 			while (--spec.field_width > 0) {
2172 				if (str < end)
2173 					*str = ' ';
2174 				++str;
2175 			}
2176 			break;
2177 		}
2178 
2179 		case FORMAT_TYPE_STR: {
2180 			const char *str_arg = args;
2181 			args += strlen(str_arg) + 1;
2182 			str = string(str, end, (char *)str_arg, spec);
2183 			break;
2184 		}
2185 
2186 		case FORMAT_TYPE_PTR:
2187 			str = pointer(fmt+1, str, end, get_arg(void *), spec);
2188 			while (isalnum(*fmt))
2189 				fmt++;
2190 			break;
2191 
2192 		case FORMAT_TYPE_PERCENT_CHAR:
2193 		case FORMAT_TYPE_INVALID:
2194 			if (str < end)
2195 				*str = '%';
2196 			++str;
2197 			break;
2198 
2199 		case FORMAT_TYPE_NRCHARS:
2200 			/* skip */
2201 			break;
2202 
2203 		default: {
2204 			unsigned long long num;
2205 
2206 			switch (spec.type) {
2207 
2208 			case FORMAT_TYPE_LONG_LONG:
2209 				num = get_arg(long long);
2210 				break;
2211 			case FORMAT_TYPE_ULONG:
2212 			case FORMAT_TYPE_LONG:
2213 				num = get_arg(unsigned long);
2214 				break;
2215 			case FORMAT_TYPE_SIZE_T:
2216 				num = get_arg(size_t);
2217 				break;
2218 			case FORMAT_TYPE_PTRDIFF:
2219 				num = get_arg(ptrdiff_t);
2220 				break;
2221 			case FORMAT_TYPE_UBYTE:
2222 				num = get_arg(unsigned char);
2223 				break;
2224 			case FORMAT_TYPE_BYTE:
2225 				num = get_arg(signed char);
2226 				break;
2227 			case FORMAT_TYPE_USHORT:
2228 				num = get_arg(unsigned short);
2229 				break;
2230 			case FORMAT_TYPE_SHORT:
2231 				num = get_arg(short);
2232 				break;
2233 			case FORMAT_TYPE_UINT:
2234 				num = get_arg(unsigned int);
2235 				break;
2236 			default:
2237 				num = get_arg(int);
2238 			}
2239 
2240 			str = number(str, end, num, spec);
2241 		} /* default: */
2242 		} /* switch(spec.type) */
2243 	} /* while(*fmt) */
2244 
2245 	if (size > 0) {
2246 		if (str < end)
2247 			*str = '\0';
2248 		else
2249 			end[-1] = '\0';
2250 	}
2251 
2252 #undef get_arg
2253 
2254 	/* the trailing null byte doesn't count towards the total */
2255 	return str - buf;
2256 }
2257 EXPORT_SYMBOL_GPL(bstr_printf);
2258 
2259 /**
2260  * bprintf - Parse a format string and place args' binary value in a buffer
2261  * @bin_buf: The buffer to place args' binary value
2262  * @size: The size of the buffer(by words(32bits), not characters)
2263  * @fmt: The format string to use
2264  * @...: Arguments for the format string
2265  *
2266  * The function returns the number of words(u32) written
2267  * into @bin_buf.
2268  */
2269 int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...)
2270 {
2271 	va_list args;
2272 	int ret;
2273 
2274 	va_start(args, fmt);
2275 	ret = vbin_printf(bin_buf, size, fmt, args);
2276 	va_end(args);
2277 
2278 	return ret;
2279 }
2280 EXPORT_SYMBOL_GPL(bprintf);
2281 
2282 #endif /* CONFIG_BINARY_PRINTF */
2283 
2284 /**
2285  * vsscanf - Unformat a buffer into a list of arguments
2286  * @buf:	input buffer
2287  * @fmt:	format of buffer
2288  * @args:	arguments
2289  */
2290 int vsscanf(const char *buf, const char *fmt, va_list args)
2291 {
2292 	const char *str = buf;
2293 	char *next;
2294 	char digit;
2295 	int num = 0;
2296 	u8 qualifier;
2297 	unsigned int base;
2298 	union {
2299 		long long s;
2300 		unsigned long long u;
2301 	} val;
2302 	s16 field_width;
2303 	bool is_sign;
2304 
2305 	while (*fmt) {
2306 		/* skip any white space in format */
2307 		/* white space in format matchs any amount of
2308 		 * white space, including none, in the input.
2309 		 */
2310 		if (isspace(*fmt)) {
2311 			fmt = skip_spaces(++fmt);
2312 			str = skip_spaces(str);
2313 		}
2314 
2315 		/* anything that is not a conversion must match exactly */
2316 		if (*fmt != '%' && *fmt) {
2317 			if (*fmt++ != *str++)
2318 				break;
2319 			continue;
2320 		}
2321 
2322 		if (!*fmt)
2323 			break;
2324 		++fmt;
2325 
2326 		/* skip this conversion.
2327 		 * advance both strings to next white space
2328 		 */
2329 		if (*fmt == '*') {
2330 			if (!*str)
2331 				break;
2332 			while (!isspace(*fmt) && *fmt != '%' && *fmt)
2333 				fmt++;
2334 			while (!isspace(*str) && *str)
2335 				str++;
2336 			continue;
2337 		}
2338 
2339 		/* get field width */
2340 		field_width = -1;
2341 		if (isdigit(*fmt)) {
2342 			field_width = skip_atoi(&fmt);
2343 			if (field_width <= 0)
2344 				break;
2345 		}
2346 
2347 		/* get conversion qualifier */
2348 		qualifier = -1;
2349 		if (*fmt == 'h' || _tolower(*fmt) == 'l' ||
2350 		    _tolower(*fmt) == 'z') {
2351 			qualifier = *fmt++;
2352 			if (unlikely(qualifier == *fmt)) {
2353 				if (qualifier == 'h') {
2354 					qualifier = 'H';
2355 					fmt++;
2356 				} else if (qualifier == 'l') {
2357 					qualifier = 'L';
2358 					fmt++;
2359 				}
2360 			}
2361 		}
2362 
2363 		if (!*fmt)
2364 			break;
2365 
2366 		if (*fmt == 'n') {
2367 			/* return number of characters read so far */
2368 			*va_arg(args, int *) = str - buf;
2369 			++fmt;
2370 			continue;
2371 		}
2372 
2373 		if (!*str)
2374 			break;
2375 
2376 		base = 10;
2377 		is_sign = 0;
2378 
2379 		switch (*fmt++) {
2380 		case 'c':
2381 		{
2382 			char *s = (char *)va_arg(args, char*);
2383 			if (field_width == -1)
2384 				field_width = 1;
2385 			do {
2386 				*s++ = *str++;
2387 			} while (--field_width > 0 && *str);
2388 			num++;
2389 		}
2390 		continue;
2391 		case 's':
2392 		{
2393 			char *s = (char *)va_arg(args, char *);
2394 			if (field_width == -1)
2395 				field_width = SHRT_MAX;
2396 			/* first, skip leading white space in buffer */
2397 			str = skip_spaces(str);
2398 
2399 			/* now copy until next white space */
2400 			while (*str && !isspace(*str) && field_width--)
2401 				*s++ = *str++;
2402 			*s = '\0';
2403 			num++;
2404 		}
2405 		continue;
2406 		case 'o':
2407 			base = 8;
2408 			break;
2409 		case 'x':
2410 		case 'X':
2411 			base = 16;
2412 			break;
2413 		case 'i':
2414 			base = 0;
2415 		case 'd':
2416 			is_sign = 1;
2417 		case 'u':
2418 			break;
2419 		case '%':
2420 			/* looking for '%' in str */
2421 			if (*str++ != '%')
2422 				return num;
2423 			continue;
2424 		default:
2425 			/* invalid format; stop here */
2426 			return num;
2427 		}
2428 
2429 		/* have some sort of integer conversion.
2430 		 * first, skip white space in buffer.
2431 		 */
2432 		str = skip_spaces(str);
2433 
2434 		digit = *str;
2435 		if (is_sign && digit == '-')
2436 			digit = *(str + 1);
2437 
2438 		if (!digit
2439 		    || (base == 16 && !isxdigit(digit))
2440 		    || (base == 10 && !isdigit(digit))
2441 		    || (base == 8 && (!isdigit(digit) || digit > '7'))
2442 		    || (base == 0 && !isdigit(digit)))
2443 			break;
2444 
2445 		if (is_sign)
2446 			val.s = qualifier != 'L' ?
2447 				simple_strtol(str, &next, base) :
2448 				simple_strtoll(str, &next, base);
2449 		else
2450 			val.u = qualifier != 'L' ?
2451 				simple_strtoul(str, &next, base) :
2452 				simple_strtoull(str, &next, base);
2453 
2454 		if (field_width > 0 && next - str > field_width) {
2455 			if (base == 0)
2456 				_parse_integer_fixup_radix(str, &base);
2457 			while (next - str > field_width) {
2458 				if (is_sign)
2459 					val.s = div_s64(val.s, base);
2460 				else
2461 					val.u = div_u64(val.u, base);
2462 				--next;
2463 			}
2464 		}
2465 
2466 		switch (qualifier) {
2467 		case 'H':	/* that's 'hh' in format */
2468 			if (is_sign)
2469 				*va_arg(args, signed char *) = val.s;
2470 			else
2471 				*va_arg(args, unsigned char *) = val.u;
2472 			break;
2473 		case 'h':
2474 			if (is_sign)
2475 				*va_arg(args, short *) = val.s;
2476 			else
2477 				*va_arg(args, unsigned short *) = val.u;
2478 			break;
2479 		case 'l':
2480 			if (is_sign)
2481 				*va_arg(args, long *) = val.s;
2482 			else
2483 				*va_arg(args, unsigned long *) = val.u;
2484 			break;
2485 		case 'L':
2486 			if (is_sign)
2487 				*va_arg(args, long long *) = val.s;
2488 			else
2489 				*va_arg(args, unsigned long long *) = val.u;
2490 			break;
2491 		case 'Z':
2492 		case 'z':
2493 			*va_arg(args, size_t *) = val.u;
2494 			break;
2495 		default:
2496 			if (is_sign)
2497 				*va_arg(args, int *) = val.s;
2498 			else
2499 				*va_arg(args, unsigned int *) = val.u;
2500 			break;
2501 		}
2502 		num++;
2503 
2504 		if (!next)
2505 			break;
2506 		str = next;
2507 	}
2508 
2509 	return num;
2510 }
2511 EXPORT_SYMBOL(vsscanf);
2512 
2513 /**
2514  * sscanf - Unformat a buffer into a list of arguments
2515  * @buf:	input buffer
2516  * @fmt:	formatting of buffer
2517  * @...:	resulting arguments
2518  */
2519 int sscanf(const char *buf, const char *fmt, ...)
2520 {
2521 	va_list args;
2522 	int i;
2523 
2524 	va_start(args, fmt);
2525 	i = vsscanf(buf, fmt, args);
2526 	va_end(args);
2527 
2528 	return i;
2529 }
2530 EXPORT_SYMBOL(sscanf);
2531