xref: /linux/lib/vsprintf.c (revision 962fad301c33dec69324dc2d9320fd84a119a24c)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  linux/lib/vsprintf.c
4  *
5  *  Copyright (C) 1991, 1992  Linus Torvalds
6  */
7 
8 /* vsprintf.c -- Lars Wirzenius & Linus Torvalds. */
9 /*
10  * Wirzenius wrote this portably, Torvalds fucked it up :-)
11  */
12 
13 /*
14  * Fri Jul 13 2001 Crutcher Dunnavant <crutcher+kernel@datastacks.com>
15  * - changed to provide snprintf and vsnprintf functions
16  * So Feb  1 16:51:32 CET 2004 Juergen Quade <quade@hsnr.de>
17  * - scnprintf and vscnprintf
18  */
19 
20 #include <stdarg.h>
21 #include <linux/build_bug.h>
22 #include <linux/clk.h>
23 #include <linux/clk-provider.h>
24 #include <linux/errname.h>
25 #include <linux/module.h>	/* for KSYM_SYMBOL_LEN */
26 #include <linux/types.h>
27 #include <linux/string.h>
28 #include <linux/ctype.h>
29 #include <linux/kernel.h>
30 #include <linux/kallsyms.h>
31 #include <linux/math64.h>
32 #include <linux/uaccess.h>
33 #include <linux/ioport.h>
34 #include <linux/dcache.h>
35 #include <linux/cred.h>
36 #include <linux/rtc.h>
37 #include <linux/time.h>
38 #include <linux/uuid.h>
39 #include <linux/of.h>
40 #include <net/addrconf.h>
41 #include <linux/siphash.h>
42 #include <linux/compiler.h>
43 #include <linux/property.h>
44 #ifdef CONFIG_BLOCK
45 #include <linux/blkdev.h>
46 #endif
47 
48 #include "../mm/internal.h"	/* For the trace_print_flags arrays */
49 
50 #include <asm/page.h>		/* for PAGE_SIZE */
51 #include <asm/byteorder.h>	/* cpu_to_le16 */
52 
53 #include <linux/string_helpers.h>
54 #include "kstrtox.h"
55 
56 /**
57  * simple_strtoull - convert a string to an unsigned long long
58  * @cp: The start of the string
59  * @endp: A pointer to the end of the parsed string will be placed here
60  * @base: The number base to use
61  *
62  * This function has caveats. Please use kstrtoull instead.
63  */
64 unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base)
65 {
66 	unsigned long long result;
67 	unsigned int rv;
68 
69 	cp = _parse_integer_fixup_radix(cp, &base);
70 	rv = _parse_integer(cp, base, &result);
71 	/* FIXME */
72 	cp += (rv & ~KSTRTOX_OVERFLOW);
73 
74 	if (endp)
75 		*endp = (char *)cp;
76 
77 	return result;
78 }
79 EXPORT_SYMBOL(simple_strtoull);
80 
81 /**
82  * simple_strtoul - convert a string to an unsigned long
83  * @cp: The start of the string
84  * @endp: A pointer to the end of the parsed string will be placed here
85  * @base: The number base to use
86  *
87  * This function has caveats. Please use kstrtoul instead.
88  */
89 unsigned long simple_strtoul(const char *cp, char **endp, unsigned int base)
90 {
91 	return simple_strtoull(cp, endp, base);
92 }
93 EXPORT_SYMBOL(simple_strtoul);
94 
95 /**
96  * simple_strtol - convert a string to a signed long
97  * @cp: The start of the string
98  * @endp: A pointer to the end of the parsed string will be placed here
99  * @base: The number base to use
100  *
101  * This function has caveats. Please use kstrtol instead.
102  */
103 long simple_strtol(const char *cp, char **endp, unsigned int base)
104 {
105 	if (*cp == '-')
106 		return -simple_strtoul(cp + 1, endp, base);
107 
108 	return simple_strtoul(cp, endp, base);
109 }
110 EXPORT_SYMBOL(simple_strtol);
111 
112 /**
113  * simple_strtoll - convert a string to a signed long long
114  * @cp: The start of the string
115  * @endp: A pointer to the end of the parsed string will be placed here
116  * @base: The number base to use
117  *
118  * This function has caveats. Please use kstrtoll instead.
119  */
120 long long simple_strtoll(const char *cp, char **endp, unsigned int base)
121 {
122 	if (*cp == '-')
123 		return -simple_strtoull(cp + 1, endp, base);
124 
125 	return simple_strtoull(cp, endp, base);
126 }
127 EXPORT_SYMBOL(simple_strtoll);
128 
129 static noinline_for_stack
130 int skip_atoi(const char **s)
131 {
132 	int i = 0;
133 
134 	do {
135 		i = i*10 + *((*s)++) - '0';
136 	} while (isdigit(**s));
137 
138 	return i;
139 }
140 
141 /*
142  * Decimal conversion is by far the most typical, and is used for
143  * /proc and /sys data. This directly impacts e.g. top performance
144  * with many processes running. We optimize it for speed by emitting
145  * two characters at a time, using a 200 byte lookup table. This
146  * roughly halves the number of multiplications compared to computing
147  * the digits one at a time. Implementation strongly inspired by the
148  * previous version, which in turn used ideas described at
149  * <http://www.cs.uiowa.edu/~jones/bcd/divide.html> (with permission
150  * from the author, Douglas W. Jones).
151  *
152  * It turns out there is precisely one 26 bit fixed-point
153  * approximation a of 64/100 for which x/100 == (x * (u64)a) >> 32
154  * holds for all x in [0, 10^8-1], namely a = 0x28f5c29. The actual
155  * range happens to be somewhat larger (x <= 1073741898), but that's
156  * irrelevant for our purpose.
157  *
158  * For dividing a number in the range [10^4, 10^6-1] by 100, we still
159  * need a 32x32->64 bit multiply, so we simply use the same constant.
160  *
161  * For dividing a number in the range [100, 10^4-1] by 100, there are
162  * several options. The simplest is (x * 0x147b) >> 19, which is valid
163  * for all x <= 43698.
164  */
165 
166 static const u16 decpair[100] = {
167 #define _(x) (__force u16) cpu_to_le16(((x % 10) | ((x / 10) << 8)) + 0x3030)
168 	_( 0), _( 1), _( 2), _( 3), _( 4), _( 5), _( 6), _( 7), _( 8), _( 9),
169 	_(10), _(11), _(12), _(13), _(14), _(15), _(16), _(17), _(18), _(19),
170 	_(20), _(21), _(22), _(23), _(24), _(25), _(26), _(27), _(28), _(29),
171 	_(30), _(31), _(32), _(33), _(34), _(35), _(36), _(37), _(38), _(39),
172 	_(40), _(41), _(42), _(43), _(44), _(45), _(46), _(47), _(48), _(49),
173 	_(50), _(51), _(52), _(53), _(54), _(55), _(56), _(57), _(58), _(59),
174 	_(60), _(61), _(62), _(63), _(64), _(65), _(66), _(67), _(68), _(69),
175 	_(70), _(71), _(72), _(73), _(74), _(75), _(76), _(77), _(78), _(79),
176 	_(80), _(81), _(82), _(83), _(84), _(85), _(86), _(87), _(88), _(89),
177 	_(90), _(91), _(92), _(93), _(94), _(95), _(96), _(97), _(98), _(99),
178 #undef _
179 };
180 
181 /*
182  * This will print a single '0' even if r == 0, since we would
183  * immediately jump to out_r where two 0s would be written but only
184  * one of them accounted for in buf. This is needed by ip4_string
185  * below. All other callers pass a non-zero value of r.
186 */
187 static noinline_for_stack
188 char *put_dec_trunc8(char *buf, unsigned r)
189 {
190 	unsigned q;
191 
192 	/* 1 <= r < 10^8 */
193 	if (r < 100)
194 		goto out_r;
195 
196 	/* 100 <= r < 10^8 */
197 	q = (r * (u64)0x28f5c29) >> 32;
198 	*((u16 *)buf) = decpair[r - 100*q];
199 	buf += 2;
200 
201 	/* 1 <= q < 10^6 */
202 	if (q < 100)
203 		goto out_q;
204 
205 	/*  100 <= q < 10^6 */
206 	r = (q * (u64)0x28f5c29) >> 32;
207 	*((u16 *)buf) = decpair[q - 100*r];
208 	buf += 2;
209 
210 	/* 1 <= r < 10^4 */
211 	if (r < 100)
212 		goto out_r;
213 
214 	/* 100 <= r < 10^4 */
215 	q = (r * 0x147b) >> 19;
216 	*((u16 *)buf) = decpair[r - 100*q];
217 	buf += 2;
218 out_q:
219 	/* 1 <= q < 100 */
220 	r = q;
221 out_r:
222 	/* 1 <= r < 100 */
223 	*((u16 *)buf) = decpair[r];
224 	buf += r < 10 ? 1 : 2;
225 	return buf;
226 }
227 
228 #if BITS_PER_LONG == 64 && BITS_PER_LONG_LONG == 64
229 static noinline_for_stack
230 char *put_dec_full8(char *buf, unsigned r)
231 {
232 	unsigned q;
233 
234 	/* 0 <= r < 10^8 */
235 	q = (r * (u64)0x28f5c29) >> 32;
236 	*((u16 *)buf) = decpair[r - 100*q];
237 	buf += 2;
238 
239 	/* 0 <= q < 10^6 */
240 	r = (q * (u64)0x28f5c29) >> 32;
241 	*((u16 *)buf) = decpair[q - 100*r];
242 	buf += 2;
243 
244 	/* 0 <= r < 10^4 */
245 	q = (r * 0x147b) >> 19;
246 	*((u16 *)buf) = decpair[r - 100*q];
247 	buf += 2;
248 
249 	/* 0 <= q < 100 */
250 	*((u16 *)buf) = decpair[q];
251 	buf += 2;
252 	return buf;
253 }
254 
255 static noinline_for_stack
256 char *put_dec(char *buf, unsigned long long n)
257 {
258 	if (n >= 100*1000*1000)
259 		buf = put_dec_full8(buf, do_div(n, 100*1000*1000));
260 	/* 1 <= n <= 1.6e11 */
261 	if (n >= 100*1000*1000)
262 		buf = put_dec_full8(buf, do_div(n, 100*1000*1000));
263 	/* 1 <= n < 1e8 */
264 	return put_dec_trunc8(buf, n);
265 }
266 
267 #elif BITS_PER_LONG == 32 && BITS_PER_LONG_LONG == 64
268 
269 static void
270 put_dec_full4(char *buf, unsigned r)
271 {
272 	unsigned q;
273 
274 	/* 0 <= r < 10^4 */
275 	q = (r * 0x147b) >> 19;
276 	*((u16 *)buf) = decpair[r - 100*q];
277 	buf += 2;
278 	/* 0 <= q < 100 */
279 	*((u16 *)buf) = decpair[q];
280 }
281 
282 /*
283  * Call put_dec_full4 on x % 10000, return x / 10000.
284  * The approximation x/10000 == (x * 0x346DC5D7) >> 43
285  * holds for all x < 1,128,869,999.  The largest value this
286  * helper will ever be asked to convert is 1,125,520,955.
287  * (second call in the put_dec code, assuming n is all-ones).
288  */
289 static noinline_for_stack
290 unsigned put_dec_helper4(char *buf, unsigned x)
291 {
292         uint32_t q = (x * (uint64_t)0x346DC5D7) >> 43;
293 
294         put_dec_full4(buf, x - q * 10000);
295         return q;
296 }
297 
298 /* Based on code by Douglas W. Jones found at
299  * <http://www.cs.uiowa.edu/~jones/bcd/decimal.html#sixtyfour>
300  * (with permission from the author).
301  * Performs no 64-bit division and hence should be fast on 32-bit machines.
302  */
303 static
304 char *put_dec(char *buf, unsigned long long n)
305 {
306 	uint32_t d3, d2, d1, q, h;
307 
308 	if (n < 100*1000*1000)
309 		return put_dec_trunc8(buf, n);
310 
311 	d1  = ((uint32_t)n >> 16); /* implicit "& 0xffff" */
312 	h   = (n >> 32);
313 	d2  = (h      ) & 0xffff;
314 	d3  = (h >> 16); /* implicit "& 0xffff" */
315 
316 	/* n = 2^48 d3 + 2^32 d2 + 2^16 d1 + d0
317 	     = 281_4749_7671_0656 d3 + 42_9496_7296 d2 + 6_5536 d1 + d0 */
318 	q   = 656 * d3 + 7296 * d2 + 5536 * d1 + ((uint32_t)n & 0xffff);
319 	q = put_dec_helper4(buf, q);
320 
321 	q += 7671 * d3 + 9496 * d2 + 6 * d1;
322 	q = put_dec_helper4(buf+4, q);
323 
324 	q += 4749 * d3 + 42 * d2;
325 	q = put_dec_helper4(buf+8, q);
326 
327 	q += 281 * d3;
328 	buf += 12;
329 	if (q)
330 		buf = put_dec_trunc8(buf, q);
331 	else while (buf[-1] == '0')
332 		--buf;
333 
334 	return buf;
335 }
336 
337 #endif
338 
339 /*
340  * Convert passed number to decimal string.
341  * Returns the length of string.  On buffer overflow, returns 0.
342  *
343  * If speed is not important, use snprintf(). It's easy to read the code.
344  */
345 int num_to_str(char *buf, int size, unsigned long long num, unsigned int width)
346 {
347 	/* put_dec requires 2-byte alignment of the buffer. */
348 	char tmp[sizeof(num) * 3] __aligned(2);
349 	int idx, len;
350 
351 	/* put_dec() may work incorrectly for num = 0 (generate "", not "0") */
352 	if (num <= 9) {
353 		tmp[0] = '0' + num;
354 		len = 1;
355 	} else {
356 		len = put_dec(tmp, num) - tmp;
357 	}
358 
359 	if (len > size || width > size)
360 		return 0;
361 
362 	if (width > len) {
363 		width = width - len;
364 		for (idx = 0; idx < width; idx++)
365 			buf[idx] = ' ';
366 	} else {
367 		width = 0;
368 	}
369 
370 	for (idx = 0; idx < len; ++idx)
371 		buf[idx + width] = tmp[len - idx - 1];
372 
373 	return len + width;
374 }
375 
376 #define SIGN	1		/* unsigned/signed, must be 1 */
377 #define LEFT	2		/* left justified */
378 #define PLUS	4		/* show plus */
379 #define SPACE	8		/* space if plus */
380 #define ZEROPAD	16		/* pad with zero, must be 16 == '0' - ' ' */
381 #define SMALL	32		/* use lowercase in hex (must be 32 == 0x20) */
382 #define SPECIAL	64		/* prefix hex with "0x", octal with "0" */
383 
384 static_assert(ZEROPAD == ('0' - ' '));
385 static_assert(SMALL == ' ');
386 
387 enum format_type {
388 	FORMAT_TYPE_NONE, /* Just a string part */
389 	FORMAT_TYPE_WIDTH,
390 	FORMAT_TYPE_PRECISION,
391 	FORMAT_TYPE_CHAR,
392 	FORMAT_TYPE_STR,
393 	FORMAT_TYPE_PTR,
394 	FORMAT_TYPE_PERCENT_CHAR,
395 	FORMAT_TYPE_INVALID,
396 	FORMAT_TYPE_LONG_LONG,
397 	FORMAT_TYPE_ULONG,
398 	FORMAT_TYPE_LONG,
399 	FORMAT_TYPE_UBYTE,
400 	FORMAT_TYPE_BYTE,
401 	FORMAT_TYPE_USHORT,
402 	FORMAT_TYPE_SHORT,
403 	FORMAT_TYPE_UINT,
404 	FORMAT_TYPE_INT,
405 	FORMAT_TYPE_SIZE_T,
406 	FORMAT_TYPE_PTRDIFF
407 };
408 
409 struct printf_spec {
410 	unsigned int	type:8;		/* format_type enum */
411 	signed int	field_width:24;	/* width of output field */
412 	unsigned int	flags:8;	/* flags to number() */
413 	unsigned int	base:8;		/* number base, 8, 10 or 16 only */
414 	signed int	precision:16;	/* # of digits/chars */
415 } __packed;
416 static_assert(sizeof(struct printf_spec) == 8);
417 
418 #define FIELD_WIDTH_MAX ((1 << 23) - 1)
419 #define PRECISION_MAX ((1 << 15) - 1)
420 
421 static noinline_for_stack
422 char *number(char *buf, char *end, unsigned long long num,
423 	     struct printf_spec spec)
424 {
425 	/* put_dec requires 2-byte alignment of the buffer. */
426 	char tmp[3 * sizeof(num)] __aligned(2);
427 	char sign;
428 	char locase;
429 	int need_pfx = ((spec.flags & SPECIAL) && spec.base != 10);
430 	int i;
431 	bool is_zero = num == 0LL;
432 	int field_width = spec.field_width;
433 	int precision = spec.precision;
434 
435 	/* locase = 0 or 0x20. ORing digits or letters with 'locase'
436 	 * produces same digits or (maybe lowercased) letters */
437 	locase = (spec.flags & SMALL);
438 	if (spec.flags & LEFT)
439 		spec.flags &= ~ZEROPAD;
440 	sign = 0;
441 	if (spec.flags & SIGN) {
442 		if ((signed long long)num < 0) {
443 			sign = '-';
444 			num = -(signed long long)num;
445 			field_width--;
446 		} else if (spec.flags & PLUS) {
447 			sign = '+';
448 			field_width--;
449 		} else if (spec.flags & SPACE) {
450 			sign = ' ';
451 			field_width--;
452 		}
453 	}
454 	if (need_pfx) {
455 		if (spec.base == 16)
456 			field_width -= 2;
457 		else if (!is_zero)
458 			field_width--;
459 	}
460 
461 	/* generate full string in tmp[], in reverse order */
462 	i = 0;
463 	if (num < spec.base)
464 		tmp[i++] = hex_asc_upper[num] | locase;
465 	else if (spec.base != 10) { /* 8 or 16 */
466 		int mask = spec.base - 1;
467 		int shift = 3;
468 
469 		if (spec.base == 16)
470 			shift = 4;
471 		do {
472 			tmp[i++] = (hex_asc_upper[((unsigned char)num) & mask] | locase);
473 			num >>= shift;
474 		} while (num);
475 	} else { /* base 10 */
476 		i = put_dec(tmp, num) - tmp;
477 	}
478 
479 	/* printing 100 using %2d gives "100", not "00" */
480 	if (i > precision)
481 		precision = i;
482 	/* leading space padding */
483 	field_width -= precision;
484 	if (!(spec.flags & (ZEROPAD | LEFT))) {
485 		while (--field_width >= 0) {
486 			if (buf < end)
487 				*buf = ' ';
488 			++buf;
489 		}
490 	}
491 	/* sign */
492 	if (sign) {
493 		if (buf < end)
494 			*buf = sign;
495 		++buf;
496 	}
497 	/* "0x" / "0" prefix */
498 	if (need_pfx) {
499 		if (spec.base == 16 || !is_zero) {
500 			if (buf < end)
501 				*buf = '0';
502 			++buf;
503 		}
504 		if (spec.base == 16) {
505 			if (buf < end)
506 				*buf = ('X' | locase);
507 			++buf;
508 		}
509 	}
510 	/* zero or space padding */
511 	if (!(spec.flags & LEFT)) {
512 		char c = ' ' + (spec.flags & ZEROPAD);
513 
514 		while (--field_width >= 0) {
515 			if (buf < end)
516 				*buf = c;
517 			++buf;
518 		}
519 	}
520 	/* hmm even more zero padding? */
521 	while (i <= --precision) {
522 		if (buf < end)
523 			*buf = '0';
524 		++buf;
525 	}
526 	/* actual digits of result */
527 	while (--i >= 0) {
528 		if (buf < end)
529 			*buf = tmp[i];
530 		++buf;
531 	}
532 	/* trailing space padding */
533 	while (--field_width >= 0) {
534 		if (buf < end)
535 			*buf = ' ';
536 		++buf;
537 	}
538 
539 	return buf;
540 }
541 
542 static noinline_for_stack
543 char *special_hex_number(char *buf, char *end, unsigned long long num, int size)
544 {
545 	struct printf_spec spec;
546 
547 	spec.type = FORMAT_TYPE_PTR;
548 	spec.field_width = 2 + 2 * size;	/* 0x + hex */
549 	spec.flags = SPECIAL | SMALL | ZEROPAD;
550 	spec.base = 16;
551 	spec.precision = -1;
552 
553 	return number(buf, end, num, spec);
554 }
555 
556 static void move_right(char *buf, char *end, unsigned len, unsigned spaces)
557 {
558 	size_t size;
559 	if (buf >= end)	/* nowhere to put anything */
560 		return;
561 	size = end - buf;
562 	if (size <= spaces) {
563 		memset(buf, ' ', size);
564 		return;
565 	}
566 	if (len) {
567 		if (len > size - spaces)
568 			len = size - spaces;
569 		memmove(buf + spaces, buf, len);
570 	}
571 	memset(buf, ' ', spaces);
572 }
573 
574 /*
575  * Handle field width padding for a string.
576  * @buf: current buffer position
577  * @n: length of string
578  * @end: end of output buffer
579  * @spec: for field width and flags
580  * Returns: new buffer position after padding.
581  */
582 static noinline_for_stack
583 char *widen_string(char *buf, int n, char *end, struct printf_spec spec)
584 {
585 	unsigned spaces;
586 
587 	if (likely(n >= spec.field_width))
588 		return buf;
589 	/* we want to pad the sucker */
590 	spaces = spec.field_width - n;
591 	if (!(spec.flags & LEFT)) {
592 		move_right(buf - n, end, n, spaces);
593 		return buf + spaces;
594 	}
595 	while (spaces--) {
596 		if (buf < end)
597 			*buf = ' ';
598 		++buf;
599 	}
600 	return buf;
601 }
602 
603 /* Handle string from a well known address. */
604 static char *string_nocheck(char *buf, char *end, const char *s,
605 			    struct printf_spec spec)
606 {
607 	int len = 0;
608 	int lim = spec.precision;
609 
610 	while (lim--) {
611 		char c = *s++;
612 		if (!c)
613 			break;
614 		if (buf < end)
615 			*buf = c;
616 		++buf;
617 		++len;
618 	}
619 	return widen_string(buf, len, end, spec);
620 }
621 
622 static char *err_ptr(char *buf, char *end, void *ptr,
623 		     struct printf_spec spec)
624 {
625 	int err = PTR_ERR(ptr);
626 	const char *sym = errname(err);
627 
628 	if (sym)
629 		return string_nocheck(buf, end, sym, spec);
630 
631 	/*
632 	 * Somebody passed ERR_PTR(-1234) or some other non-existing
633 	 * Efoo - or perhaps CONFIG_SYMBOLIC_ERRNAME=n. Fall back to
634 	 * printing it as its decimal representation.
635 	 */
636 	spec.flags |= SIGN;
637 	spec.base = 10;
638 	return number(buf, end, err, spec);
639 }
640 
641 /* Be careful: error messages must fit into the given buffer. */
642 static char *error_string(char *buf, char *end, const char *s,
643 			  struct printf_spec spec)
644 {
645 	/*
646 	 * Hard limit to avoid a completely insane messages. It actually
647 	 * works pretty well because most error messages are in
648 	 * the many pointer format modifiers.
649 	 */
650 	if (spec.precision == -1)
651 		spec.precision = 2 * sizeof(void *);
652 
653 	return string_nocheck(buf, end, s, spec);
654 }
655 
656 /*
657  * Do not call any complex external code here. Nested printk()/vsprintf()
658  * might cause infinite loops. Failures might break printk() and would
659  * be hard to debug.
660  */
661 static const char *check_pointer_msg(const void *ptr)
662 {
663 	if (!ptr)
664 		return "(null)";
665 
666 	if ((unsigned long)ptr < PAGE_SIZE || IS_ERR_VALUE(ptr))
667 		return "(efault)";
668 
669 	return NULL;
670 }
671 
672 static int check_pointer(char **buf, char *end, const void *ptr,
673 			 struct printf_spec spec)
674 {
675 	const char *err_msg;
676 
677 	err_msg = check_pointer_msg(ptr);
678 	if (err_msg) {
679 		*buf = error_string(*buf, end, err_msg, spec);
680 		return -EFAULT;
681 	}
682 
683 	return 0;
684 }
685 
686 static noinline_for_stack
687 char *string(char *buf, char *end, const char *s,
688 	     struct printf_spec spec)
689 {
690 	if (check_pointer(&buf, end, s, spec))
691 		return buf;
692 
693 	return string_nocheck(buf, end, s, spec);
694 }
695 
696 static char *pointer_string(char *buf, char *end,
697 			    const void *ptr,
698 			    struct printf_spec spec)
699 {
700 	spec.base = 16;
701 	spec.flags |= SMALL;
702 	if (spec.field_width == -1) {
703 		spec.field_width = 2 * sizeof(ptr);
704 		spec.flags |= ZEROPAD;
705 	}
706 
707 	return number(buf, end, (unsigned long int)ptr, spec);
708 }
709 
710 /* Make pointers available for printing early in the boot sequence. */
711 static int debug_boot_weak_hash __ro_after_init;
712 
713 static int __init debug_boot_weak_hash_enable(char *str)
714 {
715 	debug_boot_weak_hash = 1;
716 	pr_info("debug_boot_weak_hash enabled\n");
717 	return 0;
718 }
719 early_param("debug_boot_weak_hash", debug_boot_weak_hash_enable);
720 
721 static DEFINE_STATIC_KEY_TRUE(not_filled_random_ptr_key);
722 static siphash_key_t ptr_key __read_mostly;
723 
724 static void enable_ptr_key_workfn(struct work_struct *work)
725 {
726 	get_random_bytes(&ptr_key, sizeof(ptr_key));
727 	/* Needs to run from preemptible context */
728 	static_branch_disable(&not_filled_random_ptr_key);
729 }
730 
731 static DECLARE_WORK(enable_ptr_key_work, enable_ptr_key_workfn);
732 
733 static void fill_random_ptr_key(struct random_ready_callback *unused)
734 {
735 	/* This may be in an interrupt handler. */
736 	queue_work(system_unbound_wq, &enable_ptr_key_work);
737 }
738 
739 static struct random_ready_callback random_ready = {
740 	.func = fill_random_ptr_key
741 };
742 
743 static int __init initialize_ptr_random(void)
744 {
745 	int key_size = sizeof(ptr_key);
746 	int ret;
747 
748 	/* Use hw RNG if available. */
749 	if (get_random_bytes_arch(&ptr_key, key_size) == key_size) {
750 		static_branch_disable(&not_filled_random_ptr_key);
751 		return 0;
752 	}
753 
754 	ret = add_random_ready_callback(&random_ready);
755 	if (!ret) {
756 		return 0;
757 	} else if (ret == -EALREADY) {
758 		/* This is in preemptible context */
759 		enable_ptr_key_workfn(&enable_ptr_key_work);
760 		return 0;
761 	}
762 
763 	return ret;
764 }
765 early_initcall(initialize_ptr_random);
766 
767 /* Maps a pointer to a 32 bit unique identifier. */
768 static inline int __ptr_to_hashval(const void *ptr, unsigned long *hashval_out)
769 {
770 	unsigned long hashval;
771 
772 	if (static_branch_unlikely(&not_filled_random_ptr_key))
773 		return -EAGAIN;
774 
775 #ifdef CONFIG_64BIT
776 	hashval = (unsigned long)siphash_1u64((u64)ptr, &ptr_key);
777 	/*
778 	 * Mask off the first 32 bits, this makes explicit that we have
779 	 * modified the address (and 32 bits is plenty for a unique ID).
780 	 */
781 	hashval = hashval & 0xffffffff;
782 #else
783 	hashval = (unsigned long)siphash_1u32((u32)ptr, &ptr_key);
784 #endif
785 	*hashval_out = hashval;
786 	return 0;
787 }
788 
789 int ptr_to_hashval(const void *ptr, unsigned long *hashval_out)
790 {
791 	return __ptr_to_hashval(ptr, hashval_out);
792 }
793 
794 static char *ptr_to_id(char *buf, char *end, const void *ptr,
795 		       struct printf_spec spec)
796 {
797 	const char *str = sizeof(ptr) == 8 ? "(____ptrval____)" : "(ptrval)";
798 	unsigned long hashval;
799 	int ret;
800 
801 	/*
802 	 * Print the real pointer value for NULL and error pointers,
803 	 * as they are not actual addresses.
804 	 */
805 	if (IS_ERR_OR_NULL(ptr))
806 		return pointer_string(buf, end, ptr, spec);
807 
808 	/* When debugging early boot use non-cryptographically secure hash. */
809 	if (unlikely(debug_boot_weak_hash)) {
810 		hashval = hash_long((unsigned long)ptr, 32);
811 		return pointer_string(buf, end, (const void *)hashval, spec);
812 	}
813 
814 	ret = __ptr_to_hashval(ptr, &hashval);
815 	if (ret) {
816 		spec.field_width = 2 * sizeof(ptr);
817 		/* string length must be less than default_width */
818 		return error_string(buf, end, str, spec);
819 	}
820 
821 	return pointer_string(buf, end, (const void *)hashval, spec);
822 }
823 
824 int kptr_restrict __read_mostly;
825 
826 static noinline_for_stack
827 char *restricted_pointer(char *buf, char *end, const void *ptr,
828 			 struct printf_spec spec)
829 {
830 	switch (kptr_restrict) {
831 	case 0:
832 		/* Handle as %p, hash and do _not_ leak addresses. */
833 		return ptr_to_id(buf, end, ptr, spec);
834 	case 1: {
835 		const struct cred *cred;
836 
837 		/*
838 		 * kptr_restrict==1 cannot be used in IRQ context
839 		 * because its test for CAP_SYSLOG would be meaningless.
840 		 */
841 		if (in_irq() || in_serving_softirq() || in_nmi()) {
842 			if (spec.field_width == -1)
843 				spec.field_width = 2 * sizeof(ptr);
844 			return error_string(buf, end, "pK-error", spec);
845 		}
846 
847 		/*
848 		 * Only print the real pointer value if the current
849 		 * process has CAP_SYSLOG and is running with the
850 		 * same credentials it started with. This is because
851 		 * access to files is checked at open() time, but %pK
852 		 * checks permission at read() time. We don't want to
853 		 * leak pointer values if a binary opens a file using
854 		 * %pK and then elevates privileges before reading it.
855 		 */
856 		cred = current_cred();
857 		if (!has_capability_noaudit(current, CAP_SYSLOG) ||
858 		    !uid_eq(cred->euid, cred->uid) ||
859 		    !gid_eq(cred->egid, cred->gid))
860 			ptr = NULL;
861 		break;
862 	}
863 	case 2:
864 	default:
865 		/* Always print 0's for %pK */
866 		ptr = NULL;
867 		break;
868 	}
869 
870 	return pointer_string(buf, end, ptr, spec);
871 }
872 
873 static noinline_for_stack
874 char *dentry_name(char *buf, char *end, const struct dentry *d, struct printf_spec spec,
875 		  const char *fmt)
876 {
877 	const char *array[4], *s;
878 	const struct dentry *p;
879 	int depth;
880 	int i, n;
881 
882 	switch (fmt[1]) {
883 		case '2': case '3': case '4':
884 			depth = fmt[1] - '0';
885 			break;
886 		default:
887 			depth = 1;
888 	}
889 
890 	rcu_read_lock();
891 	for (i = 0; i < depth; i++, d = p) {
892 		if (check_pointer(&buf, end, d, spec)) {
893 			rcu_read_unlock();
894 			return buf;
895 		}
896 
897 		p = READ_ONCE(d->d_parent);
898 		array[i] = READ_ONCE(d->d_name.name);
899 		if (p == d) {
900 			if (i)
901 				array[i] = "";
902 			i++;
903 			break;
904 		}
905 	}
906 	s = array[--i];
907 	for (n = 0; n != spec.precision; n++, buf++) {
908 		char c = *s++;
909 		if (!c) {
910 			if (!i)
911 				break;
912 			c = '/';
913 			s = array[--i];
914 		}
915 		if (buf < end)
916 			*buf = c;
917 	}
918 	rcu_read_unlock();
919 	return widen_string(buf, n, end, spec);
920 }
921 
922 static noinline_for_stack
923 char *file_dentry_name(char *buf, char *end, const struct file *f,
924 			struct printf_spec spec, const char *fmt)
925 {
926 	if (check_pointer(&buf, end, f, spec))
927 		return buf;
928 
929 	return dentry_name(buf, end, f->f_path.dentry, spec, fmt);
930 }
931 #ifdef CONFIG_BLOCK
932 static noinline_for_stack
933 char *bdev_name(char *buf, char *end, struct block_device *bdev,
934 		struct printf_spec spec, const char *fmt)
935 {
936 	struct gendisk *hd;
937 
938 	if (check_pointer(&buf, end, bdev, spec))
939 		return buf;
940 
941 	hd = bdev->bd_disk;
942 	buf = string(buf, end, hd->disk_name, spec);
943 	if (bdev->bd_part->partno) {
944 		if (isdigit(hd->disk_name[strlen(hd->disk_name)-1])) {
945 			if (buf < end)
946 				*buf = 'p';
947 			buf++;
948 		}
949 		buf = number(buf, end, bdev->bd_part->partno, spec);
950 	}
951 	return buf;
952 }
953 #endif
954 
955 static noinline_for_stack
956 char *symbol_string(char *buf, char *end, void *ptr,
957 		    struct printf_spec spec, const char *fmt)
958 {
959 	unsigned long value;
960 #ifdef CONFIG_KALLSYMS
961 	char sym[KSYM_SYMBOL_LEN];
962 #endif
963 
964 	if (fmt[1] == 'R')
965 		ptr = __builtin_extract_return_addr(ptr);
966 	value = (unsigned long)ptr;
967 
968 #ifdef CONFIG_KALLSYMS
969 	if (*fmt == 'B')
970 		sprint_backtrace(sym, value);
971 	else if (*fmt != 's')
972 		sprint_symbol(sym, value);
973 	else
974 		sprint_symbol_no_offset(sym, value);
975 
976 	return string_nocheck(buf, end, sym, spec);
977 #else
978 	return special_hex_number(buf, end, value, sizeof(void *));
979 #endif
980 }
981 
982 static const struct printf_spec default_str_spec = {
983 	.field_width = -1,
984 	.precision = -1,
985 };
986 
987 static const struct printf_spec default_flag_spec = {
988 	.base = 16,
989 	.precision = -1,
990 	.flags = SPECIAL | SMALL,
991 };
992 
993 static const struct printf_spec default_dec_spec = {
994 	.base = 10,
995 	.precision = -1,
996 };
997 
998 static const struct printf_spec default_dec02_spec = {
999 	.base = 10,
1000 	.field_width = 2,
1001 	.precision = -1,
1002 	.flags = ZEROPAD,
1003 };
1004 
1005 static const struct printf_spec default_dec04_spec = {
1006 	.base = 10,
1007 	.field_width = 4,
1008 	.precision = -1,
1009 	.flags = ZEROPAD,
1010 };
1011 
1012 static noinline_for_stack
1013 char *resource_string(char *buf, char *end, struct resource *res,
1014 		      struct printf_spec spec, const char *fmt)
1015 {
1016 #ifndef IO_RSRC_PRINTK_SIZE
1017 #define IO_RSRC_PRINTK_SIZE	6
1018 #endif
1019 
1020 #ifndef MEM_RSRC_PRINTK_SIZE
1021 #define MEM_RSRC_PRINTK_SIZE	10
1022 #endif
1023 	static const struct printf_spec io_spec = {
1024 		.base = 16,
1025 		.field_width = IO_RSRC_PRINTK_SIZE,
1026 		.precision = -1,
1027 		.flags = SPECIAL | SMALL | ZEROPAD,
1028 	};
1029 	static const struct printf_spec mem_spec = {
1030 		.base = 16,
1031 		.field_width = MEM_RSRC_PRINTK_SIZE,
1032 		.precision = -1,
1033 		.flags = SPECIAL | SMALL | ZEROPAD,
1034 	};
1035 	static const struct printf_spec bus_spec = {
1036 		.base = 16,
1037 		.field_width = 2,
1038 		.precision = -1,
1039 		.flags = SMALL | ZEROPAD,
1040 	};
1041 	static const struct printf_spec str_spec = {
1042 		.field_width = -1,
1043 		.precision = 10,
1044 		.flags = LEFT,
1045 	};
1046 
1047 	/* 32-bit res (sizeof==4): 10 chars in dec, 10 in hex ("0x" + 8)
1048 	 * 64-bit res (sizeof==8): 20 chars in dec, 18 in hex ("0x" + 16) */
1049 #define RSRC_BUF_SIZE		((2 * sizeof(resource_size_t)) + 4)
1050 #define FLAG_BUF_SIZE		(2 * sizeof(res->flags))
1051 #define DECODED_BUF_SIZE	sizeof("[mem - 64bit pref window disabled]")
1052 #define RAW_BUF_SIZE		sizeof("[mem - flags 0x]")
1053 	char sym[max(2*RSRC_BUF_SIZE + DECODED_BUF_SIZE,
1054 		     2*RSRC_BUF_SIZE + FLAG_BUF_SIZE + RAW_BUF_SIZE)];
1055 
1056 	char *p = sym, *pend = sym + sizeof(sym);
1057 	int decode = (fmt[0] == 'R') ? 1 : 0;
1058 	const struct printf_spec *specp;
1059 
1060 	if (check_pointer(&buf, end, res, spec))
1061 		return buf;
1062 
1063 	*p++ = '[';
1064 	if (res->flags & IORESOURCE_IO) {
1065 		p = string_nocheck(p, pend, "io  ", str_spec);
1066 		specp = &io_spec;
1067 	} else if (res->flags & IORESOURCE_MEM) {
1068 		p = string_nocheck(p, pend, "mem ", str_spec);
1069 		specp = &mem_spec;
1070 	} else if (res->flags & IORESOURCE_IRQ) {
1071 		p = string_nocheck(p, pend, "irq ", str_spec);
1072 		specp = &default_dec_spec;
1073 	} else if (res->flags & IORESOURCE_DMA) {
1074 		p = string_nocheck(p, pend, "dma ", str_spec);
1075 		specp = &default_dec_spec;
1076 	} else if (res->flags & IORESOURCE_BUS) {
1077 		p = string_nocheck(p, pend, "bus ", str_spec);
1078 		specp = &bus_spec;
1079 	} else {
1080 		p = string_nocheck(p, pend, "??? ", str_spec);
1081 		specp = &mem_spec;
1082 		decode = 0;
1083 	}
1084 	if (decode && res->flags & IORESOURCE_UNSET) {
1085 		p = string_nocheck(p, pend, "size ", str_spec);
1086 		p = number(p, pend, resource_size(res), *specp);
1087 	} else {
1088 		p = number(p, pend, res->start, *specp);
1089 		if (res->start != res->end) {
1090 			*p++ = '-';
1091 			p = number(p, pend, res->end, *specp);
1092 		}
1093 	}
1094 	if (decode) {
1095 		if (res->flags & IORESOURCE_MEM_64)
1096 			p = string_nocheck(p, pend, " 64bit", str_spec);
1097 		if (res->flags & IORESOURCE_PREFETCH)
1098 			p = string_nocheck(p, pend, " pref", str_spec);
1099 		if (res->flags & IORESOURCE_WINDOW)
1100 			p = string_nocheck(p, pend, " window", str_spec);
1101 		if (res->flags & IORESOURCE_DISABLED)
1102 			p = string_nocheck(p, pend, " disabled", str_spec);
1103 	} else {
1104 		p = string_nocheck(p, pend, " flags ", str_spec);
1105 		p = number(p, pend, res->flags, default_flag_spec);
1106 	}
1107 	*p++ = ']';
1108 	*p = '\0';
1109 
1110 	return string_nocheck(buf, end, sym, spec);
1111 }
1112 
1113 static noinline_for_stack
1114 char *hex_string(char *buf, char *end, u8 *addr, struct printf_spec spec,
1115 		 const char *fmt)
1116 {
1117 	int i, len = 1;		/* if we pass '%ph[CDN]', field width remains
1118 				   negative value, fallback to the default */
1119 	char separator;
1120 
1121 	if (spec.field_width == 0)
1122 		/* nothing to print */
1123 		return buf;
1124 
1125 	if (check_pointer(&buf, end, addr, spec))
1126 		return buf;
1127 
1128 	switch (fmt[1]) {
1129 	case 'C':
1130 		separator = ':';
1131 		break;
1132 	case 'D':
1133 		separator = '-';
1134 		break;
1135 	case 'N':
1136 		separator = 0;
1137 		break;
1138 	default:
1139 		separator = ' ';
1140 		break;
1141 	}
1142 
1143 	if (spec.field_width > 0)
1144 		len = min_t(int, spec.field_width, 64);
1145 
1146 	for (i = 0; i < len; ++i) {
1147 		if (buf < end)
1148 			*buf = hex_asc_hi(addr[i]);
1149 		++buf;
1150 		if (buf < end)
1151 			*buf = hex_asc_lo(addr[i]);
1152 		++buf;
1153 
1154 		if (separator && i != len - 1) {
1155 			if (buf < end)
1156 				*buf = separator;
1157 			++buf;
1158 		}
1159 	}
1160 
1161 	return buf;
1162 }
1163 
1164 static noinline_for_stack
1165 char *bitmap_string(char *buf, char *end, unsigned long *bitmap,
1166 		    struct printf_spec spec, const char *fmt)
1167 {
1168 	const int CHUNKSZ = 32;
1169 	int nr_bits = max_t(int, spec.field_width, 0);
1170 	int i, chunksz;
1171 	bool first = true;
1172 
1173 	if (check_pointer(&buf, end, bitmap, spec))
1174 		return buf;
1175 
1176 	/* reused to print numbers */
1177 	spec = (struct printf_spec){ .flags = SMALL | ZEROPAD, .base = 16 };
1178 
1179 	chunksz = nr_bits & (CHUNKSZ - 1);
1180 	if (chunksz == 0)
1181 		chunksz = CHUNKSZ;
1182 
1183 	i = ALIGN(nr_bits, CHUNKSZ) - CHUNKSZ;
1184 	for (; i >= 0; i -= CHUNKSZ) {
1185 		u32 chunkmask, val;
1186 		int word, bit;
1187 
1188 		chunkmask = ((1ULL << chunksz) - 1);
1189 		word = i / BITS_PER_LONG;
1190 		bit = i % BITS_PER_LONG;
1191 		val = (bitmap[word] >> bit) & chunkmask;
1192 
1193 		if (!first) {
1194 			if (buf < end)
1195 				*buf = ',';
1196 			buf++;
1197 		}
1198 		first = false;
1199 
1200 		spec.field_width = DIV_ROUND_UP(chunksz, 4);
1201 		buf = number(buf, end, val, spec);
1202 
1203 		chunksz = CHUNKSZ;
1204 	}
1205 	return buf;
1206 }
1207 
1208 static noinline_for_stack
1209 char *bitmap_list_string(char *buf, char *end, unsigned long *bitmap,
1210 			 struct printf_spec spec, const char *fmt)
1211 {
1212 	int nr_bits = max_t(int, spec.field_width, 0);
1213 	/* current bit is 'cur', most recently seen range is [rbot, rtop] */
1214 	int cur, rbot, rtop;
1215 	bool first = true;
1216 
1217 	if (check_pointer(&buf, end, bitmap, spec))
1218 		return buf;
1219 
1220 	rbot = cur = find_first_bit(bitmap, nr_bits);
1221 	while (cur < nr_bits) {
1222 		rtop = cur;
1223 		cur = find_next_bit(bitmap, nr_bits, cur + 1);
1224 		if (cur < nr_bits && cur <= rtop + 1)
1225 			continue;
1226 
1227 		if (!first) {
1228 			if (buf < end)
1229 				*buf = ',';
1230 			buf++;
1231 		}
1232 		first = false;
1233 
1234 		buf = number(buf, end, rbot, default_dec_spec);
1235 		if (rbot < rtop) {
1236 			if (buf < end)
1237 				*buf = '-';
1238 			buf++;
1239 
1240 			buf = number(buf, end, rtop, default_dec_spec);
1241 		}
1242 
1243 		rbot = cur;
1244 	}
1245 	return buf;
1246 }
1247 
1248 static noinline_for_stack
1249 char *mac_address_string(char *buf, char *end, u8 *addr,
1250 			 struct printf_spec spec, const char *fmt)
1251 {
1252 	char mac_addr[sizeof("xx:xx:xx:xx:xx:xx")];
1253 	char *p = mac_addr;
1254 	int i;
1255 	char separator;
1256 	bool reversed = false;
1257 
1258 	if (check_pointer(&buf, end, addr, spec))
1259 		return buf;
1260 
1261 	switch (fmt[1]) {
1262 	case 'F':
1263 		separator = '-';
1264 		break;
1265 
1266 	case 'R':
1267 		reversed = true;
1268 		/* fall through */
1269 
1270 	default:
1271 		separator = ':';
1272 		break;
1273 	}
1274 
1275 	for (i = 0; i < 6; i++) {
1276 		if (reversed)
1277 			p = hex_byte_pack(p, addr[5 - i]);
1278 		else
1279 			p = hex_byte_pack(p, addr[i]);
1280 
1281 		if (fmt[0] == 'M' && i != 5)
1282 			*p++ = separator;
1283 	}
1284 	*p = '\0';
1285 
1286 	return string_nocheck(buf, end, mac_addr, spec);
1287 }
1288 
1289 static noinline_for_stack
1290 char *ip4_string(char *p, const u8 *addr, const char *fmt)
1291 {
1292 	int i;
1293 	bool leading_zeros = (fmt[0] == 'i');
1294 	int index;
1295 	int step;
1296 
1297 	switch (fmt[2]) {
1298 	case 'h':
1299 #ifdef __BIG_ENDIAN
1300 		index = 0;
1301 		step = 1;
1302 #else
1303 		index = 3;
1304 		step = -1;
1305 #endif
1306 		break;
1307 	case 'l':
1308 		index = 3;
1309 		step = -1;
1310 		break;
1311 	case 'n':
1312 	case 'b':
1313 	default:
1314 		index = 0;
1315 		step = 1;
1316 		break;
1317 	}
1318 	for (i = 0; i < 4; i++) {
1319 		char temp[4] __aligned(2);	/* hold each IP quad in reverse order */
1320 		int digits = put_dec_trunc8(temp, addr[index]) - temp;
1321 		if (leading_zeros) {
1322 			if (digits < 3)
1323 				*p++ = '0';
1324 			if (digits < 2)
1325 				*p++ = '0';
1326 		}
1327 		/* reverse the digits in the quad */
1328 		while (digits--)
1329 			*p++ = temp[digits];
1330 		if (i < 3)
1331 			*p++ = '.';
1332 		index += step;
1333 	}
1334 	*p = '\0';
1335 
1336 	return p;
1337 }
1338 
1339 static noinline_for_stack
1340 char *ip6_compressed_string(char *p, const char *addr)
1341 {
1342 	int i, j, range;
1343 	unsigned char zerolength[8];
1344 	int longest = 1;
1345 	int colonpos = -1;
1346 	u16 word;
1347 	u8 hi, lo;
1348 	bool needcolon = false;
1349 	bool useIPv4;
1350 	struct in6_addr in6;
1351 
1352 	memcpy(&in6, addr, sizeof(struct in6_addr));
1353 
1354 	useIPv4 = ipv6_addr_v4mapped(&in6) || ipv6_addr_is_isatap(&in6);
1355 
1356 	memset(zerolength, 0, sizeof(zerolength));
1357 
1358 	if (useIPv4)
1359 		range = 6;
1360 	else
1361 		range = 8;
1362 
1363 	/* find position of longest 0 run */
1364 	for (i = 0; i < range; i++) {
1365 		for (j = i; j < range; j++) {
1366 			if (in6.s6_addr16[j] != 0)
1367 				break;
1368 			zerolength[i]++;
1369 		}
1370 	}
1371 	for (i = 0; i < range; i++) {
1372 		if (zerolength[i] > longest) {
1373 			longest = zerolength[i];
1374 			colonpos = i;
1375 		}
1376 	}
1377 	if (longest == 1)		/* don't compress a single 0 */
1378 		colonpos = -1;
1379 
1380 	/* emit address */
1381 	for (i = 0; i < range; i++) {
1382 		if (i == colonpos) {
1383 			if (needcolon || i == 0)
1384 				*p++ = ':';
1385 			*p++ = ':';
1386 			needcolon = false;
1387 			i += longest - 1;
1388 			continue;
1389 		}
1390 		if (needcolon) {
1391 			*p++ = ':';
1392 			needcolon = false;
1393 		}
1394 		/* hex u16 without leading 0s */
1395 		word = ntohs(in6.s6_addr16[i]);
1396 		hi = word >> 8;
1397 		lo = word & 0xff;
1398 		if (hi) {
1399 			if (hi > 0x0f)
1400 				p = hex_byte_pack(p, hi);
1401 			else
1402 				*p++ = hex_asc_lo(hi);
1403 			p = hex_byte_pack(p, lo);
1404 		}
1405 		else if (lo > 0x0f)
1406 			p = hex_byte_pack(p, lo);
1407 		else
1408 			*p++ = hex_asc_lo(lo);
1409 		needcolon = true;
1410 	}
1411 
1412 	if (useIPv4) {
1413 		if (needcolon)
1414 			*p++ = ':';
1415 		p = ip4_string(p, &in6.s6_addr[12], "I4");
1416 	}
1417 	*p = '\0';
1418 
1419 	return p;
1420 }
1421 
1422 static noinline_for_stack
1423 char *ip6_string(char *p, const char *addr, const char *fmt)
1424 {
1425 	int i;
1426 
1427 	for (i = 0; i < 8; i++) {
1428 		p = hex_byte_pack(p, *addr++);
1429 		p = hex_byte_pack(p, *addr++);
1430 		if (fmt[0] == 'I' && i != 7)
1431 			*p++ = ':';
1432 	}
1433 	*p = '\0';
1434 
1435 	return p;
1436 }
1437 
1438 static noinline_for_stack
1439 char *ip6_addr_string(char *buf, char *end, const u8 *addr,
1440 		      struct printf_spec spec, const char *fmt)
1441 {
1442 	char ip6_addr[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255")];
1443 
1444 	if (fmt[0] == 'I' && fmt[2] == 'c')
1445 		ip6_compressed_string(ip6_addr, addr);
1446 	else
1447 		ip6_string(ip6_addr, addr, fmt);
1448 
1449 	return string_nocheck(buf, end, ip6_addr, spec);
1450 }
1451 
1452 static noinline_for_stack
1453 char *ip4_addr_string(char *buf, char *end, const u8 *addr,
1454 		      struct printf_spec spec, const char *fmt)
1455 {
1456 	char ip4_addr[sizeof("255.255.255.255")];
1457 
1458 	ip4_string(ip4_addr, addr, fmt);
1459 
1460 	return string_nocheck(buf, end, ip4_addr, spec);
1461 }
1462 
1463 static noinline_for_stack
1464 char *ip6_addr_string_sa(char *buf, char *end, const struct sockaddr_in6 *sa,
1465 			 struct printf_spec spec, const char *fmt)
1466 {
1467 	bool have_p = false, have_s = false, have_f = false, have_c = false;
1468 	char ip6_addr[sizeof("[xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255]") +
1469 		      sizeof(":12345") + sizeof("/123456789") +
1470 		      sizeof("%1234567890")];
1471 	char *p = ip6_addr, *pend = ip6_addr + sizeof(ip6_addr);
1472 	const u8 *addr = (const u8 *) &sa->sin6_addr;
1473 	char fmt6[2] = { fmt[0], '6' };
1474 	u8 off = 0;
1475 
1476 	fmt++;
1477 	while (isalpha(*++fmt)) {
1478 		switch (*fmt) {
1479 		case 'p':
1480 			have_p = true;
1481 			break;
1482 		case 'f':
1483 			have_f = true;
1484 			break;
1485 		case 's':
1486 			have_s = true;
1487 			break;
1488 		case 'c':
1489 			have_c = true;
1490 			break;
1491 		}
1492 	}
1493 
1494 	if (have_p || have_s || have_f) {
1495 		*p = '[';
1496 		off = 1;
1497 	}
1498 
1499 	if (fmt6[0] == 'I' && have_c)
1500 		p = ip6_compressed_string(ip6_addr + off, addr);
1501 	else
1502 		p = ip6_string(ip6_addr + off, addr, fmt6);
1503 
1504 	if (have_p || have_s || have_f)
1505 		*p++ = ']';
1506 
1507 	if (have_p) {
1508 		*p++ = ':';
1509 		p = number(p, pend, ntohs(sa->sin6_port), spec);
1510 	}
1511 	if (have_f) {
1512 		*p++ = '/';
1513 		p = number(p, pend, ntohl(sa->sin6_flowinfo &
1514 					  IPV6_FLOWINFO_MASK), spec);
1515 	}
1516 	if (have_s) {
1517 		*p++ = '%';
1518 		p = number(p, pend, sa->sin6_scope_id, spec);
1519 	}
1520 	*p = '\0';
1521 
1522 	return string_nocheck(buf, end, ip6_addr, spec);
1523 }
1524 
1525 static noinline_for_stack
1526 char *ip4_addr_string_sa(char *buf, char *end, const struct sockaddr_in *sa,
1527 			 struct printf_spec spec, const char *fmt)
1528 {
1529 	bool have_p = false;
1530 	char *p, ip4_addr[sizeof("255.255.255.255") + sizeof(":12345")];
1531 	char *pend = ip4_addr + sizeof(ip4_addr);
1532 	const u8 *addr = (const u8 *) &sa->sin_addr.s_addr;
1533 	char fmt4[3] = { fmt[0], '4', 0 };
1534 
1535 	fmt++;
1536 	while (isalpha(*++fmt)) {
1537 		switch (*fmt) {
1538 		case 'p':
1539 			have_p = true;
1540 			break;
1541 		case 'h':
1542 		case 'l':
1543 		case 'n':
1544 		case 'b':
1545 			fmt4[2] = *fmt;
1546 			break;
1547 		}
1548 	}
1549 
1550 	p = ip4_string(ip4_addr, addr, fmt4);
1551 	if (have_p) {
1552 		*p++ = ':';
1553 		p = number(p, pend, ntohs(sa->sin_port), spec);
1554 	}
1555 	*p = '\0';
1556 
1557 	return string_nocheck(buf, end, ip4_addr, spec);
1558 }
1559 
1560 static noinline_for_stack
1561 char *ip_addr_string(char *buf, char *end, const void *ptr,
1562 		     struct printf_spec spec, const char *fmt)
1563 {
1564 	char *err_fmt_msg;
1565 
1566 	if (check_pointer(&buf, end, ptr, spec))
1567 		return buf;
1568 
1569 	switch (fmt[1]) {
1570 	case '6':
1571 		return ip6_addr_string(buf, end, ptr, spec, fmt);
1572 	case '4':
1573 		return ip4_addr_string(buf, end, ptr, spec, fmt);
1574 	case 'S': {
1575 		const union {
1576 			struct sockaddr		raw;
1577 			struct sockaddr_in	v4;
1578 			struct sockaddr_in6	v6;
1579 		} *sa = ptr;
1580 
1581 		switch (sa->raw.sa_family) {
1582 		case AF_INET:
1583 			return ip4_addr_string_sa(buf, end, &sa->v4, spec, fmt);
1584 		case AF_INET6:
1585 			return ip6_addr_string_sa(buf, end, &sa->v6, spec, fmt);
1586 		default:
1587 			return error_string(buf, end, "(einval)", spec);
1588 		}}
1589 	}
1590 
1591 	err_fmt_msg = fmt[0] == 'i' ? "(%pi?)" : "(%pI?)";
1592 	return error_string(buf, end, err_fmt_msg, spec);
1593 }
1594 
1595 static noinline_for_stack
1596 char *escaped_string(char *buf, char *end, u8 *addr, struct printf_spec spec,
1597 		     const char *fmt)
1598 {
1599 	bool found = true;
1600 	int count = 1;
1601 	unsigned int flags = 0;
1602 	int len;
1603 
1604 	if (spec.field_width == 0)
1605 		return buf;				/* nothing to print */
1606 
1607 	if (check_pointer(&buf, end, addr, spec))
1608 		return buf;
1609 
1610 	do {
1611 		switch (fmt[count++]) {
1612 		case 'a':
1613 			flags |= ESCAPE_ANY;
1614 			break;
1615 		case 'c':
1616 			flags |= ESCAPE_SPECIAL;
1617 			break;
1618 		case 'h':
1619 			flags |= ESCAPE_HEX;
1620 			break;
1621 		case 'n':
1622 			flags |= ESCAPE_NULL;
1623 			break;
1624 		case 'o':
1625 			flags |= ESCAPE_OCTAL;
1626 			break;
1627 		case 'p':
1628 			flags |= ESCAPE_NP;
1629 			break;
1630 		case 's':
1631 			flags |= ESCAPE_SPACE;
1632 			break;
1633 		default:
1634 			found = false;
1635 			break;
1636 		}
1637 	} while (found);
1638 
1639 	if (!flags)
1640 		flags = ESCAPE_ANY_NP;
1641 
1642 	len = spec.field_width < 0 ? 1 : spec.field_width;
1643 
1644 	/*
1645 	 * string_escape_mem() writes as many characters as it can to
1646 	 * the given buffer, and returns the total size of the output
1647 	 * had the buffer been big enough.
1648 	 */
1649 	buf += string_escape_mem(addr, len, buf, buf < end ? end - buf : 0, flags, NULL);
1650 
1651 	return buf;
1652 }
1653 
1654 static char *va_format(char *buf, char *end, struct va_format *va_fmt,
1655 		       struct printf_spec spec, const char *fmt)
1656 {
1657 	va_list va;
1658 
1659 	if (check_pointer(&buf, end, va_fmt, spec))
1660 		return buf;
1661 
1662 	va_copy(va, *va_fmt->va);
1663 	buf += vsnprintf(buf, end > buf ? end - buf : 0, va_fmt->fmt, va);
1664 	va_end(va);
1665 
1666 	return buf;
1667 }
1668 
1669 static noinline_for_stack
1670 char *uuid_string(char *buf, char *end, const u8 *addr,
1671 		  struct printf_spec spec, const char *fmt)
1672 {
1673 	char uuid[UUID_STRING_LEN + 1];
1674 	char *p = uuid;
1675 	int i;
1676 	const u8 *index = uuid_index;
1677 	bool uc = false;
1678 
1679 	if (check_pointer(&buf, end, addr, spec))
1680 		return buf;
1681 
1682 	switch (*(++fmt)) {
1683 	case 'L':
1684 		uc = true;		/* fall-through */
1685 	case 'l':
1686 		index = guid_index;
1687 		break;
1688 	case 'B':
1689 		uc = true;
1690 		break;
1691 	}
1692 
1693 	for (i = 0; i < 16; i++) {
1694 		if (uc)
1695 			p = hex_byte_pack_upper(p, addr[index[i]]);
1696 		else
1697 			p = hex_byte_pack(p, addr[index[i]]);
1698 		switch (i) {
1699 		case 3:
1700 		case 5:
1701 		case 7:
1702 		case 9:
1703 			*p++ = '-';
1704 			break;
1705 		}
1706 	}
1707 
1708 	*p = 0;
1709 
1710 	return string_nocheck(buf, end, uuid, spec);
1711 }
1712 
1713 static noinline_for_stack
1714 char *netdev_bits(char *buf, char *end, const void *addr,
1715 		  struct printf_spec spec,  const char *fmt)
1716 {
1717 	unsigned long long num;
1718 	int size;
1719 
1720 	if (check_pointer(&buf, end, addr, spec))
1721 		return buf;
1722 
1723 	switch (fmt[1]) {
1724 	case 'F':
1725 		num = *(const netdev_features_t *)addr;
1726 		size = sizeof(netdev_features_t);
1727 		break;
1728 	default:
1729 		return error_string(buf, end, "(%pN?)", spec);
1730 	}
1731 
1732 	return special_hex_number(buf, end, num, size);
1733 }
1734 
1735 static noinline_for_stack
1736 char *address_val(char *buf, char *end, const void *addr,
1737 		  struct printf_spec spec, const char *fmt)
1738 {
1739 	unsigned long long num;
1740 	int size;
1741 
1742 	if (check_pointer(&buf, end, addr, spec))
1743 		return buf;
1744 
1745 	switch (fmt[1]) {
1746 	case 'd':
1747 		num = *(const dma_addr_t *)addr;
1748 		size = sizeof(dma_addr_t);
1749 		break;
1750 	case 'p':
1751 	default:
1752 		num = *(const phys_addr_t *)addr;
1753 		size = sizeof(phys_addr_t);
1754 		break;
1755 	}
1756 
1757 	return special_hex_number(buf, end, num, size);
1758 }
1759 
1760 static noinline_for_stack
1761 char *date_str(char *buf, char *end, const struct rtc_time *tm, bool r)
1762 {
1763 	int year = tm->tm_year + (r ? 0 : 1900);
1764 	int mon = tm->tm_mon + (r ? 0 : 1);
1765 
1766 	buf = number(buf, end, year, default_dec04_spec);
1767 	if (buf < end)
1768 		*buf = '-';
1769 	buf++;
1770 
1771 	buf = number(buf, end, mon, default_dec02_spec);
1772 	if (buf < end)
1773 		*buf = '-';
1774 	buf++;
1775 
1776 	return number(buf, end, tm->tm_mday, default_dec02_spec);
1777 }
1778 
1779 static noinline_for_stack
1780 char *time_str(char *buf, char *end, const struct rtc_time *tm, bool r)
1781 {
1782 	buf = number(buf, end, tm->tm_hour, default_dec02_spec);
1783 	if (buf < end)
1784 		*buf = ':';
1785 	buf++;
1786 
1787 	buf = number(buf, end, tm->tm_min, default_dec02_spec);
1788 	if (buf < end)
1789 		*buf = ':';
1790 	buf++;
1791 
1792 	return number(buf, end, tm->tm_sec, default_dec02_spec);
1793 }
1794 
1795 static noinline_for_stack
1796 char *rtc_str(char *buf, char *end, const struct rtc_time *tm,
1797 	      struct printf_spec spec, const char *fmt)
1798 {
1799 	bool have_t = true, have_d = true;
1800 	bool raw = false;
1801 	int count = 2;
1802 
1803 	if (check_pointer(&buf, end, tm, spec))
1804 		return buf;
1805 
1806 	switch (fmt[count]) {
1807 	case 'd':
1808 		have_t = false;
1809 		count++;
1810 		break;
1811 	case 't':
1812 		have_d = false;
1813 		count++;
1814 		break;
1815 	}
1816 
1817 	raw = fmt[count] == 'r';
1818 
1819 	if (have_d)
1820 		buf = date_str(buf, end, tm, raw);
1821 	if (have_d && have_t) {
1822 		/* Respect ISO 8601 */
1823 		if (buf < end)
1824 			*buf = 'T';
1825 		buf++;
1826 	}
1827 	if (have_t)
1828 		buf = time_str(buf, end, tm, raw);
1829 
1830 	return buf;
1831 }
1832 
1833 static noinline_for_stack
1834 char *time64_str(char *buf, char *end, const time64_t time,
1835 		 struct printf_spec spec, const char *fmt)
1836 {
1837 	struct rtc_time rtc_time;
1838 	struct tm tm;
1839 
1840 	time64_to_tm(time, 0, &tm);
1841 
1842 	rtc_time.tm_sec = tm.tm_sec;
1843 	rtc_time.tm_min = tm.tm_min;
1844 	rtc_time.tm_hour = tm.tm_hour;
1845 	rtc_time.tm_mday = tm.tm_mday;
1846 	rtc_time.tm_mon = tm.tm_mon;
1847 	rtc_time.tm_year = tm.tm_year;
1848 	rtc_time.tm_wday = tm.tm_wday;
1849 	rtc_time.tm_yday = tm.tm_yday;
1850 
1851 	rtc_time.tm_isdst = 0;
1852 
1853 	return rtc_str(buf, end, &rtc_time, spec, fmt);
1854 }
1855 
1856 static noinline_for_stack
1857 char *time_and_date(char *buf, char *end, void *ptr, struct printf_spec spec,
1858 		    const char *fmt)
1859 {
1860 	switch (fmt[1]) {
1861 	case 'R':
1862 		return rtc_str(buf, end, (const struct rtc_time *)ptr, spec, fmt);
1863 	case 'T':
1864 		return time64_str(buf, end, *(const time64_t *)ptr, spec, fmt);
1865 	default:
1866 		return error_string(buf, end, "(%pt?)", spec);
1867 	}
1868 }
1869 
1870 static noinline_for_stack
1871 char *clock(char *buf, char *end, struct clk *clk, struct printf_spec spec,
1872 	    const char *fmt)
1873 {
1874 	if (!IS_ENABLED(CONFIG_HAVE_CLK))
1875 		return error_string(buf, end, "(%pC?)", spec);
1876 
1877 	if (check_pointer(&buf, end, clk, spec))
1878 		return buf;
1879 
1880 	switch (fmt[1]) {
1881 	case 'n':
1882 	default:
1883 #ifdef CONFIG_COMMON_CLK
1884 		return string(buf, end, __clk_get_name(clk), spec);
1885 #else
1886 		return ptr_to_id(buf, end, clk, spec);
1887 #endif
1888 	}
1889 }
1890 
1891 static
1892 char *format_flags(char *buf, char *end, unsigned long flags,
1893 					const struct trace_print_flags *names)
1894 {
1895 	unsigned long mask;
1896 
1897 	for ( ; flags && names->name; names++) {
1898 		mask = names->mask;
1899 		if ((flags & mask) != mask)
1900 			continue;
1901 
1902 		buf = string(buf, end, names->name, default_str_spec);
1903 
1904 		flags &= ~mask;
1905 		if (flags) {
1906 			if (buf < end)
1907 				*buf = '|';
1908 			buf++;
1909 		}
1910 	}
1911 
1912 	if (flags)
1913 		buf = number(buf, end, flags, default_flag_spec);
1914 
1915 	return buf;
1916 }
1917 
1918 static noinline_for_stack
1919 char *flags_string(char *buf, char *end, void *flags_ptr,
1920 		   struct printf_spec spec, const char *fmt)
1921 {
1922 	unsigned long flags;
1923 	const struct trace_print_flags *names;
1924 
1925 	if (check_pointer(&buf, end, flags_ptr, spec))
1926 		return buf;
1927 
1928 	switch (fmt[1]) {
1929 	case 'p':
1930 		flags = *(unsigned long *)flags_ptr;
1931 		/* Remove zone id */
1932 		flags &= (1UL << NR_PAGEFLAGS) - 1;
1933 		names = pageflag_names;
1934 		break;
1935 	case 'v':
1936 		flags = *(unsigned long *)flags_ptr;
1937 		names = vmaflag_names;
1938 		break;
1939 	case 'g':
1940 		flags = (__force unsigned long)(*(gfp_t *)flags_ptr);
1941 		names = gfpflag_names;
1942 		break;
1943 	default:
1944 		return error_string(buf, end, "(%pG?)", spec);
1945 	}
1946 
1947 	return format_flags(buf, end, flags, names);
1948 }
1949 
1950 static noinline_for_stack
1951 char *fwnode_full_name_string(struct fwnode_handle *fwnode, char *buf,
1952 			      char *end)
1953 {
1954 	int depth;
1955 
1956 	/* Loop starting from the root node to the current node. */
1957 	for (depth = fwnode_count_parents(fwnode); depth >= 0; depth--) {
1958 		struct fwnode_handle *__fwnode =
1959 			fwnode_get_nth_parent(fwnode, depth);
1960 
1961 		buf = string(buf, end, fwnode_get_name_prefix(__fwnode),
1962 			     default_str_spec);
1963 		buf = string(buf, end, fwnode_get_name(__fwnode),
1964 			     default_str_spec);
1965 
1966 		fwnode_handle_put(__fwnode);
1967 	}
1968 
1969 	return buf;
1970 }
1971 
1972 static noinline_for_stack
1973 char *device_node_string(char *buf, char *end, struct device_node *dn,
1974 			 struct printf_spec spec, const char *fmt)
1975 {
1976 	char tbuf[sizeof("xxxx") + 1];
1977 	const char *p;
1978 	int ret;
1979 	char *buf_start = buf;
1980 	struct property *prop;
1981 	bool has_mult, pass;
1982 
1983 	struct printf_spec str_spec = spec;
1984 	str_spec.field_width = -1;
1985 
1986 	if (fmt[0] != 'F')
1987 		return error_string(buf, end, "(%pO?)", spec);
1988 
1989 	if (!IS_ENABLED(CONFIG_OF))
1990 		return error_string(buf, end, "(%pOF?)", spec);
1991 
1992 	if (check_pointer(&buf, end, dn, spec))
1993 		return buf;
1994 
1995 	/* simple case without anything any more format specifiers */
1996 	fmt++;
1997 	if (fmt[0] == '\0' || strcspn(fmt,"fnpPFcC") > 0)
1998 		fmt = "f";
1999 
2000 	for (pass = false; strspn(fmt,"fnpPFcC"); fmt++, pass = true) {
2001 		int precision;
2002 		if (pass) {
2003 			if (buf < end)
2004 				*buf = ':';
2005 			buf++;
2006 		}
2007 
2008 		switch (*fmt) {
2009 		case 'f':	/* full_name */
2010 			buf = fwnode_full_name_string(of_fwnode_handle(dn), buf,
2011 						      end);
2012 			break;
2013 		case 'n':	/* name */
2014 			p = fwnode_get_name(of_fwnode_handle(dn));
2015 			precision = str_spec.precision;
2016 			str_spec.precision = strchrnul(p, '@') - p;
2017 			buf = string(buf, end, p, str_spec);
2018 			str_spec.precision = precision;
2019 			break;
2020 		case 'p':	/* phandle */
2021 			buf = number(buf, end, (unsigned int)dn->phandle, default_dec_spec);
2022 			break;
2023 		case 'P':	/* path-spec */
2024 			p = fwnode_get_name(of_fwnode_handle(dn));
2025 			if (!p[1])
2026 				p = "/";
2027 			buf = string(buf, end, p, str_spec);
2028 			break;
2029 		case 'F':	/* flags */
2030 			tbuf[0] = of_node_check_flag(dn, OF_DYNAMIC) ? 'D' : '-';
2031 			tbuf[1] = of_node_check_flag(dn, OF_DETACHED) ? 'd' : '-';
2032 			tbuf[2] = of_node_check_flag(dn, OF_POPULATED) ? 'P' : '-';
2033 			tbuf[3] = of_node_check_flag(dn, OF_POPULATED_BUS) ? 'B' : '-';
2034 			tbuf[4] = 0;
2035 			buf = string_nocheck(buf, end, tbuf, str_spec);
2036 			break;
2037 		case 'c':	/* major compatible string */
2038 			ret = of_property_read_string(dn, "compatible", &p);
2039 			if (!ret)
2040 				buf = string(buf, end, p, str_spec);
2041 			break;
2042 		case 'C':	/* full compatible string */
2043 			has_mult = false;
2044 			of_property_for_each_string(dn, "compatible", prop, p) {
2045 				if (has_mult)
2046 					buf = string_nocheck(buf, end, ",", str_spec);
2047 				buf = string_nocheck(buf, end, "\"", str_spec);
2048 				buf = string(buf, end, p, str_spec);
2049 				buf = string_nocheck(buf, end, "\"", str_spec);
2050 
2051 				has_mult = true;
2052 			}
2053 			break;
2054 		default:
2055 			break;
2056 		}
2057 	}
2058 
2059 	return widen_string(buf, buf - buf_start, end, spec);
2060 }
2061 
2062 static noinline_for_stack
2063 char *fwnode_string(char *buf, char *end, struct fwnode_handle *fwnode,
2064 		    struct printf_spec spec, const char *fmt)
2065 {
2066 	struct printf_spec str_spec = spec;
2067 	char *buf_start = buf;
2068 
2069 	str_spec.field_width = -1;
2070 
2071 	if (*fmt != 'w')
2072 		return error_string(buf, end, "(%pf?)", spec);
2073 
2074 	if (check_pointer(&buf, end, fwnode, spec))
2075 		return buf;
2076 
2077 	fmt++;
2078 
2079 	switch (*fmt) {
2080 	case 'P':	/* name */
2081 		buf = string(buf, end, fwnode_get_name(fwnode), str_spec);
2082 		break;
2083 	case 'f':	/* full_name */
2084 	default:
2085 		buf = fwnode_full_name_string(fwnode, buf, end);
2086 		break;
2087 	}
2088 
2089 	return widen_string(buf, buf - buf_start, end, spec);
2090 }
2091 
2092 /*
2093  * Show a '%p' thing.  A kernel extension is that the '%p' is followed
2094  * by an extra set of alphanumeric characters that are extended format
2095  * specifiers.
2096  *
2097  * Please update scripts/checkpatch.pl when adding/removing conversion
2098  * characters.  (Search for "check for vsprintf extension").
2099  *
2100  * Right now we handle:
2101  *
2102  * - 'S' For symbolic direct pointers (or function descriptors) with offset
2103  * - 's' For symbolic direct pointers (or function descriptors) without offset
2104  * - '[Ss]R' as above with __builtin_extract_return_addr() translation
2105  * - '[Ff]' %pf and %pF were obsoleted and later removed in favor of
2106  *	    %ps and %pS. Be careful when re-using these specifiers.
2107  * - 'B' For backtraced symbolic direct pointers with offset
2108  * - 'R' For decoded struct resource, e.g., [mem 0x0-0x1f 64bit pref]
2109  * - 'r' For raw struct resource, e.g., [mem 0x0-0x1f flags 0x201]
2110  * - 'b[l]' For a bitmap, the number of bits is determined by the field
2111  *       width which must be explicitly specified either as part of the
2112  *       format string '%32b[l]' or through '%*b[l]', [l] selects
2113  *       range-list format instead of hex format
2114  * - 'M' For a 6-byte MAC address, it prints the address in the
2115  *       usual colon-separated hex notation
2116  * - 'm' For a 6-byte MAC address, it prints the hex address without colons
2117  * - 'MF' For a 6-byte MAC FDDI address, it prints the address
2118  *       with a dash-separated hex notation
2119  * - '[mM]R' For a 6-byte MAC address, Reverse order (Bluetooth)
2120  * - 'I' [46] for IPv4/IPv6 addresses printed in the usual way
2121  *       IPv4 uses dot-separated decimal without leading 0's (1.2.3.4)
2122  *       IPv6 uses colon separated network-order 16 bit hex with leading 0's
2123  *       [S][pfs]
2124  *       Generic IPv4/IPv6 address (struct sockaddr *) that falls back to
2125  *       [4] or [6] and is able to print port [p], flowinfo [f], scope [s]
2126  * - 'i' [46] for 'raw' IPv4/IPv6 addresses
2127  *       IPv6 omits the colons (01020304...0f)
2128  *       IPv4 uses dot-separated decimal with leading 0's (010.123.045.006)
2129  *       [S][pfs]
2130  *       Generic IPv4/IPv6 address (struct sockaddr *) that falls back to
2131  *       [4] or [6] and is able to print port [p], flowinfo [f], scope [s]
2132  * - '[Ii][4S][hnbl]' IPv4 addresses in host, network, big or little endian order
2133  * - 'I[6S]c' for IPv6 addresses printed as specified by
2134  *       https://tools.ietf.org/html/rfc5952
2135  * - 'E[achnops]' For an escaped buffer, where rules are defined by combination
2136  *                of the following flags (see string_escape_mem() for the
2137  *                details):
2138  *                  a - ESCAPE_ANY
2139  *                  c - ESCAPE_SPECIAL
2140  *                  h - ESCAPE_HEX
2141  *                  n - ESCAPE_NULL
2142  *                  o - ESCAPE_OCTAL
2143  *                  p - ESCAPE_NP
2144  *                  s - ESCAPE_SPACE
2145  *                By default ESCAPE_ANY_NP is used.
2146  * - 'U' For a 16 byte UUID/GUID, it prints the UUID/GUID in the form
2147  *       "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
2148  *       Options for %pU are:
2149  *         b big endian lower case hex (default)
2150  *         B big endian UPPER case hex
2151  *         l little endian lower case hex
2152  *         L little endian UPPER case hex
2153  *           big endian output byte order is:
2154  *             [0][1][2][3]-[4][5]-[6][7]-[8][9]-[10][11][12][13][14][15]
2155  *           little endian output byte order is:
2156  *             [3][2][1][0]-[5][4]-[7][6]-[8][9]-[10][11][12][13][14][15]
2157  * - 'V' For a struct va_format which contains a format string * and va_list *,
2158  *       call vsnprintf(->format, *->va_list).
2159  *       Implements a "recursive vsnprintf".
2160  *       Do not use this feature without some mechanism to verify the
2161  *       correctness of the format string and va_list arguments.
2162  * - 'K' For a kernel pointer that should be hidden from unprivileged users
2163  * - 'NF' For a netdev_features_t
2164  * - 'h[CDN]' For a variable-length buffer, it prints it as a hex string with
2165  *            a certain separator (' ' by default):
2166  *              C colon
2167  *              D dash
2168  *              N no separator
2169  *            The maximum supported length is 64 bytes of the input. Consider
2170  *            to use print_hex_dump() for the larger input.
2171  * - 'a[pd]' For address types [p] phys_addr_t, [d] dma_addr_t and derivatives
2172  *           (default assumed to be phys_addr_t, passed by reference)
2173  * - 'd[234]' For a dentry name (optionally 2-4 last components)
2174  * - 'D[234]' Same as 'd' but for a struct file
2175  * - 'g' For block_device name (gendisk + partition number)
2176  * - 't[RT][dt][r]' For time and date as represented by:
2177  *      R    struct rtc_time
2178  *      T    time64_t
2179  * - 'C' For a clock, it prints the name (Common Clock Framework) or address
2180  *       (legacy clock framework) of the clock
2181  * - 'Cn' For a clock, it prints the name (Common Clock Framework) or address
2182  *        (legacy clock framework) of the clock
2183  * - 'G' For flags to be printed as a collection of symbolic strings that would
2184  *       construct the specific value. Supported flags given by option:
2185  *       p page flags (see struct page) given as pointer to unsigned long
2186  *       g gfp flags (GFP_* and __GFP_*) given as pointer to gfp_t
2187  *       v vma flags (VM_*) given as pointer to unsigned long
2188  * - 'OF[fnpPcCF]'  For a device tree object
2189  *                  Without any optional arguments prints the full_name
2190  *                  f device node full_name
2191  *                  n device node name
2192  *                  p device node phandle
2193  *                  P device node path spec (name + @unit)
2194  *                  F device node flags
2195  *                  c major compatible string
2196  *                  C full compatible string
2197  * - 'fw[fP]'	For a firmware node (struct fwnode_handle) pointer
2198  *		Without an option prints the full name of the node
2199  *		f full name
2200  *		P node name, including a possible unit address
2201  * - 'x' For printing the address. Equivalent to "%lx".
2202  * - '[ku]s' For a BPF/tracing related format specifier, e.g. used out of
2203  *           bpf_trace_printk() where [ku] prefix specifies either kernel (k)
2204  *           or user (u) memory to probe, and:
2205  *              s a string, equivalent to "%s" on direct vsnprintf() use
2206  *
2207  * ** When making changes please also update:
2208  *	Documentation/core-api/printk-formats.rst
2209  *
2210  * Note: The default behaviour (unadorned %p) is to hash the address,
2211  * rendering it useful as a unique identifier.
2212  */
2213 static noinline_for_stack
2214 char *pointer(const char *fmt, char *buf, char *end, void *ptr,
2215 	      struct printf_spec spec)
2216 {
2217 	switch (*fmt) {
2218 	case 'S':
2219 	case 's':
2220 		ptr = dereference_symbol_descriptor(ptr);
2221 		/* Fallthrough */
2222 	case 'B':
2223 		return symbol_string(buf, end, ptr, spec, fmt);
2224 	case 'R':
2225 	case 'r':
2226 		return resource_string(buf, end, ptr, spec, fmt);
2227 	case 'h':
2228 		return hex_string(buf, end, ptr, spec, fmt);
2229 	case 'b':
2230 		switch (fmt[1]) {
2231 		case 'l':
2232 			return bitmap_list_string(buf, end, ptr, spec, fmt);
2233 		default:
2234 			return bitmap_string(buf, end, ptr, spec, fmt);
2235 		}
2236 	case 'M':			/* Colon separated: 00:01:02:03:04:05 */
2237 	case 'm':			/* Contiguous: 000102030405 */
2238 					/* [mM]F (FDDI) */
2239 					/* [mM]R (Reverse order; Bluetooth) */
2240 		return mac_address_string(buf, end, ptr, spec, fmt);
2241 	case 'I':			/* Formatted IP supported
2242 					 * 4:	1.2.3.4
2243 					 * 6:	0001:0203:...:0708
2244 					 * 6c:	1::708 or 1::1.2.3.4
2245 					 */
2246 	case 'i':			/* Contiguous:
2247 					 * 4:	001.002.003.004
2248 					 * 6:   000102...0f
2249 					 */
2250 		return ip_addr_string(buf, end, ptr, spec, fmt);
2251 	case 'E':
2252 		return escaped_string(buf, end, ptr, spec, fmt);
2253 	case 'U':
2254 		return uuid_string(buf, end, ptr, spec, fmt);
2255 	case 'V':
2256 		return va_format(buf, end, ptr, spec, fmt);
2257 	case 'K':
2258 		return restricted_pointer(buf, end, ptr, spec);
2259 	case 'N':
2260 		return netdev_bits(buf, end, ptr, spec, fmt);
2261 	case 'a':
2262 		return address_val(buf, end, ptr, spec, fmt);
2263 	case 'd':
2264 		return dentry_name(buf, end, ptr, spec, fmt);
2265 	case 't':
2266 		return time_and_date(buf, end, ptr, spec, fmt);
2267 	case 'C':
2268 		return clock(buf, end, ptr, spec, fmt);
2269 	case 'D':
2270 		return file_dentry_name(buf, end, ptr, spec, fmt);
2271 #ifdef CONFIG_BLOCK
2272 	case 'g':
2273 		return bdev_name(buf, end, ptr, spec, fmt);
2274 #endif
2275 
2276 	case 'G':
2277 		return flags_string(buf, end, ptr, spec, fmt);
2278 	case 'O':
2279 		return device_node_string(buf, end, ptr, spec, fmt + 1);
2280 	case 'f':
2281 		return fwnode_string(buf, end, ptr, spec, fmt + 1);
2282 	case 'x':
2283 		return pointer_string(buf, end, ptr, spec);
2284 	case 'e':
2285 		/* %pe with a non-ERR_PTR gets treated as plain %p */
2286 		if (!IS_ERR(ptr))
2287 			break;
2288 		return err_ptr(buf, end, ptr, spec);
2289 	case 'u':
2290 	case 'k':
2291 		switch (fmt[1]) {
2292 		case 's':
2293 			return string(buf, end, ptr, spec);
2294 		default:
2295 			return error_string(buf, end, "(einval)", spec);
2296 		}
2297 	}
2298 
2299 	/* default is to _not_ leak addresses, hash before printing */
2300 	return ptr_to_id(buf, end, ptr, spec);
2301 }
2302 
2303 /*
2304  * Helper function to decode printf style format.
2305  * Each call decode a token from the format and return the
2306  * number of characters read (or likely the delta where it wants
2307  * to go on the next call).
2308  * The decoded token is returned through the parameters
2309  *
2310  * 'h', 'l', or 'L' for integer fields
2311  * 'z' support added 23/7/1999 S.H.
2312  * 'z' changed to 'Z' --davidm 1/25/99
2313  * 'Z' changed to 'z' --adobriyan 2017-01-25
2314  * 't' added for ptrdiff_t
2315  *
2316  * @fmt: the format string
2317  * @type of the token returned
2318  * @flags: various flags such as +, -, # tokens..
2319  * @field_width: overwritten width
2320  * @base: base of the number (octal, hex, ...)
2321  * @precision: precision of a number
2322  * @qualifier: qualifier of a number (long, size_t, ...)
2323  */
2324 static noinline_for_stack
2325 int format_decode(const char *fmt, struct printf_spec *spec)
2326 {
2327 	const char *start = fmt;
2328 	char qualifier;
2329 
2330 	/* we finished early by reading the field width */
2331 	if (spec->type == FORMAT_TYPE_WIDTH) {
2332 		if (spec->field_width < 0) {
2333 			spec->field_width = -spec->field_width;
2334 			spec->flags |= LEFT;
2335 		}
2336 		spec->type = FORMAT_TYPE_NONE;
2337 		goto precision;
2338 	}
2339 
2340 	/* we finished early by reading the precision */
2341 	if (spec->type == FORMAT_TYPE_PRECISION) {
2342 		if (spec->precision < 0)
2343 			spec->precision = 0;
2344 
2345 		spec->type = FORMAT_TYPE_NONE;
2346 		goto qualifier;
2347 	}
2348 
2349 	/* By default */
2350 	spec->type = FORMAT_TYPE_NONE;
2351 
2352 	for (; *fmt ; ++fmt) {
2353 		if (*fmt == '%')
2354 			break;
2355 	}
2356 
2357 	/* Return the current non-format string */
2358 	if (fmt != start || !*fmt)
2359 		return fmt - start;
2360 
2361 	/* Process flags */
2362 	spec->flags = 0;
2363 
2364 	while (1) { /* this also skips first '%' */
2365 		bool found = true;
2366 
2367 		++fmt;
2368 
2369 		switch (*fmt) {
2370 		case '-': spec->flags |= LEFT;    break;
2371 		case '+': spec->flags |= PLUS;    break;
2372 		case ' ': spec->flags |= SPACE;   break;
2373 		case '#': spec->flags |= SPECIAL; break;
2374 		case '0': spec->flags |= ZEROPAD; break;
2375 		default:  found = false;
2376 		}
2377 
2378 		if (!found)
2379 			break;
2380 	}
2381 
2382 	/* get field width */
2383 	spec->field_width = -1;
2384 
2385 	if (isdigit(*fmt))
2386 		spec->field_width = skip_atoi(&fmt);
2387 	else if (*fmt == '*') {
2388 		/* it's the next argument */
2389 		spec->type = FORMAT_TYPE_WIDTH;
2390 		return ++fmt - start;
2391 	}
2392 
2393 precision:
2394 	/* get the precision */
2395 	spec->precision = -1;
2396 	if (*fmt == '.') {
2397 		++fmt;
2398 		if (isdigit(*fmt)) {
2399 			spec->precision = skip_atoi(&fmt);
2400 			if (spec->precision < 0)
2401 				spec->precision = 0;
2402 		} else if (*fmt == '*') {
2403 			/* it's the next argument */
2404 			spec->type = FORMAT_TYPE_PRECISION;
2405 			return ++fmt - start;
2406 		}
2407 	}
2408 
2409 qualifier:
2410 	/* get the conversion qualifier */
2411 	qualifier = 0;
2412 	if (*fmt == 'h' || _tolower(*fmt) == 'l' ||
2413 	    *fmt == 'z' || *fmt == 't') {
2414 		qualifier = *fmt++;
2415 		if (unlikely(qualifier == *fmt)) {
2416 			if (qualifier == 'l') {
2417 				qualifier = 'L';
2418 				++fmt;
2419 			} else if (qualifier == 'h') {
2420 				qualifier = 'H';
2421 				++fmt;
2422 			}
2423 		}
2424 	}
2425 
2426 	/* default base */
2427 	spec->base = 10;
2428 	switch (*fmt) {
2429 	case 'c':
2430 		spec->type = FORMAT_TYPE_CHAR;
2431 		return ++fmt - start;
2432 
2433 	case 's':
2434 		spec->type = FORMAT_TYPE_STR;
2435 		return ++fmt - start;
2436 
2437 	case 'p':
2438 		spec->type = FORMAT_TYPE_PTR;
2439 		return ++fmt - start;
2440 
2441 	case '%':
2442 		spec->type = FORMAT_TYPE_PERCENT_CHAR;
2443 		return ++fmt - start;
2444 
2445 	/* integer number formats - set up the flags and "break" */
2446 	case 'o':
2447 		spec->base = 8;
2448 		break;
2449 
2450 	case 'x':
2451 		spec->flags |= SMALL;
2452 		/* fall through */
2453 
2454 	case 'X':
2455 		spec->base = 16;
2456 		break;
2457 
2458 	case 'd':
2459 	case 'i':
2460 		spec->flags |= SIGN;
2461 	case 'u':
2462 		break;
2463 
2464 	case 'n':
2465 		/*
2466 		 * Since %n poses a greater security risk than
2467 		 * utility, treat it as any other invalid or
2468 		 * unsupported format specifier.
2469 		 */
2470 		/* Fall-through */
2471 
2472 	default:
2473 		WARN_ONCE(1, "Please remove unsupported %%%c in format string\n", *fmt);
2474 		spec->type = FORMAT_TYPE_INVALID;
2475 		return fmt - start;
2476 	}
2477 
2478 	if (qualifier == 'L')
2479 		spec->type = FORMAT_TYPE_LONG_LONG;
2480 	else if (qualifier == 'l') {
2481 		BUILD_BUG_ON(FORMAT_TYPE_ULONG + SIGN != FORMAT_TYPE_LONG);
2482 		spec->type = FORMAT_TYPE_ULONG + (spec->flags & SIGN);
2483 	} else if (qualifier == 'z') {
2484 		spec->type = FORMAT_TYPE_SIZE_T;
2485 	} else if (qualifier == 't') {
2486 		spec->type = FORMAT_TYPE_PTRDIFF;
2487 	} else if (qualifier == 'H') {
2488 		BUILD_BUG_ON(FORMAT_TYPE_UBYTE + SIGN != FORMAT_TYPE_BYTE);
2489 		spec->type = FORMAT_TYPE_UBYTE + (spec->flags & SIGN);
2490 	} else if (qualifier == 'h') {
2491 		BUILD_BUG_ON(FORMAT_TYPE_USHORT + SIGN != FORMAT_TYPE_SHORT);
2492 		spec->type = FORMAT_TYPE_USHORT + (spec->flags & SIGN);
2493 	} else {
2494 		BUILD_BUG_ON(FORMAT_TYPE_UINT + SIGN != FORMAT_TYPE_INT);
2495 		spec->type = FORMAT_TYPE_UINT + (spec->flags & SIGN);
2496 	}
2497 
2498 	return ++fmt - start;
2499 }
2500 
2501 static void
2502 set_field_width(struct printf_spec *spec, int width)
2503 {
2504 	spec->field_width = width;
2505 	if (WARN_ONCE(spec->field_width != width, "field width %d too large", width)) {
2506 		spec->field_width = clamp(width, -FIELD_WIDTH_MAX, FIELD_WIDTH_MAX);
2507 	}
2508 }
2509 
2510 static void
2511 set_precision(struct printf_spec *spec, int prec)
2512 {
2513 	spec->precision = prec;
2514 	if (WARN_ONCE(spec->precision != prec, "precision %d too large", prec)) {
2515 		spec->precision = clamp(prec, 0, PRECISION_MAX);
2516 	}
2517 }
2518 
2519 /**
2520  * vsnprintf - Format a string and place it in a buffer
2521  * @buf: The buffer to place the result into
2522  * @size: The size of the buffer, including the trailing null space
2523  * @fmt: The format string to use
2524  * @args: Arguments for the format string
2525  *
2526  * This function generally follows C99 vsnprintf, but has some
2527  * extensions and a few limitations:
2528  *
2529  *  - ``%n`` is unsupported
2530  *  - ``%p*`` is handled by pointer()
2531  *
2532  * See pointer() or Documentation/core-api/printk-formats.rst for more
2533  * extensive description.
2534  *
2535  * **Please update the documentation in both places when making changes**
2536  *
2537  * The return value is the number of characters which would
2538  * be generated for the given input, excluding the trailing
2539  * '\0', as per ISO C99. If you want to have the exact
2540  * number of characters written into @buf as return value
2541  * (not including the trailing '\0'), use vscnprintf(). If the
2542  * return is greater than or equal to @size, the resulting
2543  * string is truncated.
2544  *
2545  * If you're not already dealing with a va_list consider using snprintf().
2546  */
2547 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
2548 {
2549 	unsigned long long num;
2550 	char *str, *end;
2551 	struct printf_spec spec = {0};
2552 
2553 	/* Reject out-of-range values early.  Large positive sizes are
2554 	   used for unknown buffer sizes. */
2555 	if (WARN_ON_ONCE(size > INT_MAX))
2556 		return 0;
2557 
2558 	str = buf;
2559 	end = buf + size;
2560 
2561 	/* Make sure end is always >= buf */
2562 	if (end < buf) {
2563 		end = ((void *)-1);
2564 		size = end - buf;
2565 	}
2566 
2567 	while (*fmt) {
2568 		const char *old_fmt = fmt;
2569 		int read = format_decode(fmt, &spec);
2570 
2571 		fmt += read;
2572 
2573 		switch (spec.type) {
2574 		case FORMAT_TYPE_NONE: {
2575 			int copy = read;
2576 			if (str < end) {
2577 				if (copy > end - str)
2578 					copy = end - str;
2579 				memcpy(str, old_fmt, copy);
2580 			}
2581 			str += read;
2582 			break;
2583 		}
2584 
2585 		case FORMAT_TYPE_WIDTH:
2586 			set_field_width(&spec, va_arg(args, int));
2587 			break;
2588 
2589 		case FORMAT_TYPE_PRECISION:
2590 			set_precision(&spec, va_arg(args, int));
2591 			break;
2592 
2593 		case FORMAT_TYPE_CHAR: {
2594 			char c;
2595 
2596 			if (!(spec.flags & LEFT)) {
2597 				while (--spec.field_width > 0) {
2598 					if (str < end)
2599 						*str = ' ';
2600 					++str;
2601 
2602 				}
2603 			}
2604 			c = (unsigned char) va_arg(args, int);
2605 			if (str < end)
2606 				*str = c;
2607 			++str;
2608 			while (--spec.field_width > 0) {
2609 				if (str < end)
2610 					*str = ' ';
2611 				++str;
2612 			}
2613 			break;
2614 		}
2615 
2616 		case FORMAT_TYPE_STR:
2617 			str = string(str, end, va_arg(args, char *), spec);
2618 			break;
2619 
2620 		case FORMAT_TYPE_PTR:
2621 			str = pointer(fmt, str, end, va_arg(args, void *),
2622 				      spec);
2623 			while (isalnum(*fmt))
2624 				fmt++;
2625 			break;
2626 
2627 		case FORMAT_TYPE_PERCENT_CHAR:
2628 			if (str < end)
2629 				*str = '%';
2630 			++str;
2631 			break;
2632 
2633 		case FORMAT_TYPE_INVALID:
2634 			/*
2635 			 * Presumably the arguments passed gcc's type
2636 			 * checking, but there is no safe or sane way
2637 			 * for us to continue parsing the format and
2638 			 * fetching from the va_list; the remaining
2639 			 * specifiers and arguments would be out of
2640 			 * sync.
2641 			 */
2642 			goto out;
2643 
2644 		default:
2645 			switch (spec.type) {
2646 			case FORMAT_TYPE_LONG_LONG:
2647 				num = va_arg(args, long long);
2648 				break;
2649 			case FORMAT_TYPE_ULONG:
2650 				num = va_arg(args, unsigned long);
2651 				break;
2652 			case FORMAT_TYPE_LONG:
2653 				num = va_arg(args, long);
2654 				break;
2655 			case FORMAT_TYPE_SIZE_T:
2656 				if (spec.flags & SIGN)
2657 					num = va_arg(args, ssize_t);
2658 				else
2659 					num = va_arg(args, size_t);
2660 				break;
2661 			case FORMAT_TYPE_PTRDIFF:
2662 				num = va_arg(args, ptrdiff_t);
2663 				break;
2664 			case FORMAT_TYPE_UBYTE:
2665 				num = (unsigned char) va_arg(args, int);
2666 				break;
2667 			case FORMAT_TYPE_BYTE:
2668 				num = (signed char) va_arg(args, int);
2669 				break;
2670 			case FORMAT_TYPE_USHORT:
2671 				num = (unsigned short) va_arg(args, int);
2672 				break;
2673 			case FORMAT_TYPE_SHORT:
2674 				num = (short) va_arg(args, int);
2675 				break;
2676 			case FORMAT_TYPE_INT:
2677 				num = (int) va_arg(args, int);
2678 				break;
2679 			default:
2680 				num = va_arg(args, unsigned int);
2681 			}
2682 
2683 			str = number(str, end, num, spec);
2684 		}
2685 	}
2686 
2687 out:
2688 	if (size > 0) {
2689 		if (str < end)
2690 			*str = '\0';
2691 		else
2692 			end[-1] = '\0';
2693 	}
2694 
2695 	/* the trailing null byte doesn't count towards the total */
2696 	return str-buf;
2697 
2698 }
2699 EXPORT_SYMBOL(vsnprintf);
2700 
2701 /**
2702  * vscnprintf - Format a string and place it in a buffer
2703  * @buf: The buffer to place the result into
2704  * @size: The size of the buffer, including the trailing null space
2705  * @fmt: The format string to use
2706  * @args: Arguments for the format string
2707  *
2708  * The return value is the number of characters which have been written into
2709  * the @buf not including the trailing '\0'. If @size is == 0 the function
2710  * returns 0.
2711  *
2712  * If you're not already dealing with a va_list consider using scnprintf().
2713  *
2714  * See the vsnprintf() documentation for format string extensions over C99.
2715  */
2716 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
2717 {
2718 	int i;
2719 
2720 	i = vsnprintf(buf, size, fmt, args);
2721 
2722 	if (likely(i < size))
2723 		return i;
2724 	if (size != 0)
2725 		return size - 1;
2726 	return 0;
2727 }
2728 EXPORT_SYMBOL(vscnprintf);
2729 
2730 /**
2731  * snprintf - Format a string and place it in a buffer
2732  * @buf: The buffer to place the result into
2733  * @size: The size of the buffer, including the trailing null space
2734  * @fmt: The format string to use
2735  * @...: Arguments for the format string
2736  *
2737  * The return value is the number of characters which would be
2738  * generated for the given input, excluding the trailing null,
2739  * as per ISO C99.  If the return is greater than or equal to
2740  * @size, the resulting string is truncated.
2741  *
2742  * See the vsnprintf() documentation for format string extensions over C99.
2743  */
2744 int snprintf(char *buf, size_t size, const char *fmt, ...)
2745 {
2746 	va_list args;
2747 	int i;
2748 
2749 	va_start(args, fmt);
2750 	i = vsnprintf(buf, size, fmt, args);
2751 	va_end(args);
2752 
2753 	return i;
2754 }
2755 EXPORT_SYMBOL(snprintf);
2756 
2757 /**
2758  * scnprintf - Format a string and place it in a buffer
2759  * @buf: The buffer to place the result into
2760  * @size: The size of the buffer, including the trailing null space
2761  * @fmt: The format string to use
2762  * @...: Arguments for the format string
2763  *
2764  * The return value is the number of characters written into @buf not including
2765  * the trailing '\0'. If @size is == 0 the function returns 0.
2766  */
2767 
2768 int scnprintf(char *buf, size_t size, const char *fmt, ...)
2769 {
2770 	va_list args;
2771 	int i;
2772 
2773 	va_start(args, fmt);
2774 	i = vscnprintf(buf, size, fmt, args);
2775 	va_end(args);
2776 
2777 	return i;
2778 }
2779 EXPORT_SYMBOL(scnprintf);
2780 
2781 /**
2782  * vsprintf - Format a string and place it in a buffer
2783  * @buf: The buffer to place the result into
2784  * @fmt: The format string to use
2785  * @args: Arguments for the format string
2786  *
2787  * The function returns the number of characters written
2788  * into @buf. Use vsnprintf() or vscnprintf() in order to avoid
2789  * buffer overflows.
2790  *
2791  * If you're not already dealing with a va_list consider using sprintf().
2792  *
2793  * See the vsnprintf() documentation for format string extensions over C99.
2794  */
2795 int vsprintf(char *buf, const char *fmt, va_list args)
2796 {
2797 	return vsnprintf(buf, INT_MAX, fmt, args);
2798 }
2799 EXPORT_SYMBOL(vsprintf);
2800 
2801 /**
2802  * sprintf - Format a string and place it in a buffer
2803  * @buf: The buffer to place the result into
2804  * @fmt: The format string to use
2805  * @...: Arguments for the format string
2806  *
2807  * The function returns the number of characters written
2808  * into @buf. Use snprintf() or scnprintf() in order to avoid
2809  * buffer overflows.
2810  *
2811  * See the vsnprintf() documentation for format string extensions over C99.
2812  */
2813 int sprintf(char *buf, const char *fmt, ...)
2814 {
2815 	va_list args;
2816 	int i;
2817 
2818 	va_start(args, fmt);
2819 	i = vsnprintf(buf, INT_MAX, fmt, args);
2820 	va_end(args);
2821 
2822 	return i;
2823 }
2824 EXPORT_SYMBOL(sprintf);
2825 
2826 #ifdef CONFIG_BINARY_PRINTF
2827 /*
2828  * bprintf service:
2829  * vbin_printf() - VA arguments to binary data
2830  * bstr_printf() - Binary data to text string
2831  */
2832 
2833 /**
2834  * vbin_printf - Parse a format string and place args' binary value in a buffer
2835  * @bin_buf: The buffer to place args' binary value
2836  * @size: The size of the buffer(by words(32bits), not characters)
2837  * @fmt: The format string to use
2838  * @args: Arguments for the format string
2839  *
2840  * The format follows C99 vsnprintf, except %n is ignored, and its argument
2841  * is skipped.
2842  *
2843  * The return value is the number of words(32bits) which would be generated for
2844  * the given input.
2845  *
2846  * NOTE:
2847  * If the return value is greater than @size, the resulting bin_buf is NOT
2848  * valid for bstr_printf().
2849  */
2850 int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args)
2851 {
2852 	struct printf_spec spec = {0};
2853 	char *str, *end;
2854 	int width;
2855 
2856 	str = (char *)bin_buf;
2857 	end = (char *)(bin_buf + size);
2858 
2859 #define save_arg(type)							\
2860 ({									\
2861 	unsigned long long value;					\
2862 	if (sizeof(type) == 8) {					\
2863 		unsigned long long val8;				\
2864 		str = PTR_ALIGN(str, sizeof(u32));			\
2865 		val8 = va_arg(args, unsigned long long);		\
2866 		if (str + sizeof(type) <= end) {			\
2867 			*(u32 *)str = *(u32 *)&val8;			\
2868 			*(u32 *)(str + 4) = *((u32 *)&val8 + 1);	\
2869 		}							\
2870 		value = val8;						\
2871 	} else {							\
2872 		unsigned int val4;					\
2873 		str = PTR_ALIGN(str, sizeof(type));			\
2874 		val4 = va_arg(args, int);				\
2875 		if (str + sizeof(type) <= end)				\
2876 			*(typeof(type) *)str = (type)(long)val4;	\
2877 		value = (unsigned long long)val4;			\
2878 	}								\
2879 	str += sizeof(type);						\
2880 	value;								\
2881 })
2882 
2883 	while (*fmt) {
2884 		int read = format_decode(fmt, &spec);
2885 
2886 		fmt += read;
2887 
2888 		switch (spec.type) {
2889 		case FORMAT_TYPE_NONE:
2890 		case FORMAT_TYPE_PERCENT_CHAR:
2891 			break;
2892 		case FORMAT_TYPE_INVALID:
2893 			goto out;
2894 
2895 		case FORMAT_TYPE_WIDTH:
2896 		case FORMAT_TYPE_PRECISION:
2897 			width = (int)save_arg(int);
2898 			/* Pointers may require the width */
2899 			if (*fmt == 'p')
2900 				set_field_width(&spec, width);
2901 			break;
2902 
2903 		case FORMAT_TYPE_CHAR:
2904 			save_arg(char);
2905 			break;
2906 
2907 		case FORMAT_TYPE_STR: {
2908 			const char *save_str = va_arg(args, char *);
2909 			const char *err_msg;
2910 			size_t len;
2911 
2912 			err_msg = check_pointer_msg(save_str);
2913 			if (err_msg)
2914 				save_str = err_msg;
2915 
2916 			len = strlen(save_str) + 1;
2917 			if (str + len < end)
2918 				memcpy(str, save_str, len);
2919 			str += len;
2920 			break;
2921 		}
2922 
2923 		case FORMAT_TYPE_PTR:
2924 			/* Dereferenced pointers must be done now */
2925 			switch (*fmt) {
2926 			/* Dereference of functions is still OK */
2927 			case 'S':
2928 			case 's':
2929 			case 'x':
2930 			case 'K':
2931 			case 'e':
2932 				save_arg(void *);
2933 				break;
2934 			default:
2935 				if (!isalnum(*fmt)) {
2936 					save_arg(void *);
2937 					break;
2938 				}
2939 				str = pointer(fmt, str, end, va_arg(args, void *),
2940 					      spec);
2941 				if (str + 1 < end)
2942 					*str++ = '\0';
2943 				else
2944 					end[-1] = '\0'; /* Must be nul terminated */
2945 			}
2946 			/* skip all alphanumeric pointer suffixes */
2947 			while (isalnum(*fmt))
2948 				fmt++;
2949 			break;
2950 
2951 		default:
2952 			switch (spec.type) {
2953 
2954 			case FORMAT_TYPE_LONG_LONG:
2955 				save_arg(long long);
2956 				break;
2957 			case FORMAT_TYPE_ULONG:
2958 			case FORMAT_TYPE_LONG:
2959 				save_arg(unsigned long);
2960 				break;
2961 			case FORMAT_TYPE_SIZE_T:
2962 				save_arg(size_t);
2963 				break;
2964 			case FORMAT_TYPE_PTRDIFF:
2965 				save_arg(ptrdiff_t);
2966 				break;
2967 			case FORMAT_TYPE_UBYTE:
2968 			case FORMAT_TYPE_BYTE:
2969 				save_arg(char);
2970 				break;
2971 			case FORMAT_TYPE_USHORT:
2972 			case FORMAT_TYPE_SHORT:
2973 				save_arg(short);
2974 				break;
2975 			default:
2976 				save_arg(int);
2977 			}
2978 		}
2979 	}
2980 
2981 out:
2982 	return (u32 *)(PTR_ALIGN(str, sizeof(u32))) - bin_buf;
2983 #undef save_arg
2984 }
2985 EXPORT_SYMBOL_GPL(vbin_printf);
2986 
2987 /**
2988  * bstr_printf - Format a string from binary arguments and place it in a buffer
2989  * @buf: The buffer to place the result into
2990  * @size: The size of the buffer, including the trailing null space
2991  * @fmt: The format string to use
2992  * @bin_buf: Binary arguments for the format string
2993  *
2994  * This function like C99 vsnprintf, but the difference is that vsnprintf gets
2995  * arguments from stack, and bstr_printf gets arguments from @bin_buf which is
2996  * a binary buffer that generated by vbin_printf.
2997  *
2998  * The format follows C99 vsnprintf, but has some extensions:
2999  *  see vsnprintf comment for details.
3000  *
3001  * The return value is the number of characters which would
3002  * be generated for the given input, excluding the trailing
3003  * '\0', as per ISO C99. If you want to have the exact
3004  * number of characters written into @buf as return value
3005  * (not including the trailing '\0'), use vscnprintf(). If the
3006  * return is greater than or equal to @size, the resulting
3007  * string is truncated.
3008  */
3009 int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf)
3010 {
3011 	struct printf_spec spec = {0};
3012 	char *str, *end;
3013 	const char *args = (const char *)bin_buf;
3014 
3015 	if (WARN_ON_ONCE(size > INT_MAX))
3016 		return 0;
3017 
3018 	str = buf;
3019 	end = buf + size;
3020 
3021 #define get_arg(type)							\
3022 ({									\
3023 	typeof(type) value;						\
3024 	if (sizeof(type) == 8) {					\
3025 		args = PTR_ALIGN(args, sizeof(u32));			\
3026 		*(u32 *)&value = *(u32 *)args;				\
3027 		*((u32 *)&value + 1) = *(u32 *)(args + 4);		\
3028 	} else {							\
3029 		args = PTR_ALIGN(args, sizeof(type));			\
3030 		value = *(typeof(type) *)args;				\
3031 	}								\
3032 	args += sizeof(type);						\
3033 	value;								\
3034 })
3035 
3036 	/* Make sure end is always >= buf */
3037 	if (end < buf) {
3038 		end = ((void *)-1);
3039 		size = end - buf;
3040 	}
3041 
3042 	while (*fmt) {
3043 		const char *old_fmt = fmt;
3044 		int read = format_decode(fmt, &spec);
3045 
3046 		fmt += read;
3047 
3048 		switch (spec.type) {
3049 		case FORMAT_TYPE_NONE: {
3050 			int copy = read;
3051 			if (str < end) {
3052 				if (copy > end - str)
3053 					copy = end - str;
3054 				memcpy(str, old_fmt, copy);
3055 			}
3056 			str += read;
3057 			break;
3058 		}
3059 
3060 		case FORMAT_TYPE_WIDTH:
3061 			set_field_width(&spec, get_arg(int));
3062 			break;
3063 
3064 		case FORMAT_TYPE_PRECISION:
3065 			set_precision(&spec, get_arg(int));
3066 			break;
3067 
3068 		case FORMAT_TYPE_CHAR: {
3069 			char c;
3070 
3071 			if (!(spec.flags & LEFT)) {
3072 				while (--spec.field_width > 0) {
3073 					if (str < end)
3074 						*str = ' ';
3075 					++str;
3076 				}
3077 			}
3078 			c = (unsigned char) get_arg(char);
3079 			if (str < end)
3080 				*str = c;
3081 			++str;
3082 			while (--spec.field_width > 0) {
3083 				if (str < end)
3084 					*str = ' ';
3085 				++str;
3086 			}
3087 			break;
3088 		}
3089 
3090 		case FORMAT_TYPE_STR: {
3091 			const char *str_arg = args;
3092 			args += strlen(str_arg) + 1;
3093 			str = string(str, end, (char *)str_arg, spec);
3094 			break;
3095 		}
3096 
3097 		case FORMAT_TYPE_PTR: {
3098 			bool process = false;
3099 			int copy, len;
3100 			/* Non function dereferences were already done */
3101 			switch (*fmt) {
3102 			case 'S':
3103 			case 's':
3104 			case 'F':
3105 			case 'f':
3106 			case 'x':
3107 			case 'K':
3108 			case 'e':
3109 				process = true;
3110 				break;
3111 			default:
3112 				if (!isalnum(*fmt)) {
3113 					process = true;
3114 					break;
3115 				}
3116 				/* Pointer dereference was already processed */
3117 				if (str < end) {
3118 					len = copy = strlen(args);
3119 					if (copy > end - str)
3120 						copy = end - str;
3121 					memcpy(str, args, copy);
3122 					str += len;
3123 					args += len + 1;
3124 				}
3125 			}
3126 			if (process)
3127 				str = pointer(fmt, str, end, get_arg(void *), spec);
3128 
3129 			while (isalnum(*fmt))
3130 				fmt++;
3131 			break;
3132 		}
3133 
3134 		case FORMAT_TYPE_PERCENT_CHAR:
3135 			if (str < end)
3136 				*str = '%';
3137 			++str;
3138 			break;
3139 
3140 		case FORMAT_TYPE_INVALID:
3141 			goto out;
3142 
3143 		default: {
3144 			unsigned long long num;
3145 
3146 			switch (spec.type) {
3147 
3148 			case FORMAT_TYPE_LONG_LONG:
3149 				num = get_arg(long long);
3150 				break;
3151 			case FORMAT_TYPE_ULONG:
3152 			case FORMAT_TYPE_LONG:
3153 				num = get_arg(unsigned long);
3154 				break;
3155 			case FORMAT_TYPE_SIZE_T:
3156 				num = get_arg(size_t);
3157 				break;
3158 			case FORMAT_TYPE_PTRDIFF:
3159 				num = get_arg(ptrdiff_t);
3160 				break;
3161 			case FORMAT_TYPE_UBYTE:
3162 				num = get_arg(unsigned char);
3163 				break;
3164 			case FORMAT_TYPE_BYTE:
3165 				num = get_arg(signed char);
3166 				break;
3167 			case FORMAT_TYPE_USHORT:
3168 				num = get_arg(unsigned short);
3169 				break;
3170 			case FORMAT_TYPE_SHORT:
3171 				num = get_arg(short);
3172 				break;
3173 			case FORMAT_TYPE_UINT:
3174 				num = get_arg(unsigned int);
3175 				break;
3176 			default:
3177 				num = get_arg(int);
3178 			}
3179 
3180 			str = number(str, end, num, spec);
3181 		} /* default: */
3182 		} /* switch(spec.type) */
3183 	} /* while(*fmt) */
3184 
3185 out:
3186 	if (size > 0) {
3187 		if (str < end)
3188 			*str = '\0';
3189 		else
3190 			end[-1] = '\0';
3191 	}
3192 
3193 #undef get_arg
3194 
3195 	/* the trailing null byte doesn't count towards the total */
3196 	return str - buf;
3197 }
3198 EXPORT_SYMBOL_GPL(bstr_printf);
3199 
3200 /**
3201  * bprintf - Parse a format string and place args' binary value in a buffer
3202  * @bin_buf: The buffer to place args' binary value
3203  * @size: The size of the buffer(by words(32bits), not characters)
3204  * @fmt: The format string to use
3205  * @...: Arguments for the format string
3206  *
3207  * The function returns the number of words(u32) written
3208  * into @bin_buf.
3209  */
3210 int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...)
3211 {
3212 	va_list args;
3213 	int ret;
3214 
3215 	va_start(args, fmt);
3216 	ret = vbin_printf(bin_buf, size, fmt, args);
3217 	va_end(args);
3218 
3219 	return ret;
3220 }
3221 EXPORT_SYMBOL_GPL(bprintf);
3222 
3223 #endif /* CONFIG_BINARY_PRINTF */
3224 
3225 /**
3226  * vsscanf - Unformat a buffer into a list of arguments
3227  * @buf:	input buffer
3228  * @fmt:	format of buffer
3229  * @args:	arguments
3230  */
3231 int vsscanf(const char *buf, const char *fmt, va_list args)
3232 {
3233 	const char *str = buf;
3234 	char *next;
3235 	char digit;
3236 	int num = 0;
3237 	u8 qualifier;
3238 	unsigned int base;
3239 	union {
3240 		long long s;
3241 		unsigned long long u;
3242 	} val;
3243 	s16 field_width;
3244 	bool is_sign;
3245 
3246 	while (*fmt) {
3247 		/* skip any white space in format */
3248 		/* white space in format matchs any amount of
3249 		 * white space, including none, in the input.
3250 		 */
3251 		if (isspace(*fmt)) {
3252 			fmt = skip_spaces(++fmt);
3253 			str = skip_spaces(str);
3254 		}
3255 
3256 		/* anything that is not a conversion must match exactly */
3257 		if (*fmt != '%' && *fmt) {
3258 			if (*fmt++ != *str++)
3259 				break;
3260 			continue;
3261 		}
3262 
3263 		if (!*fmt)
3264 			break;
3265 		++fmt;
3266 
3267 		/* skip this conversion.
3268 		 * advance both strings to next white space
3269 		 */
3270 		if (*fmt == '*') {
3271 			if (!*str)
3272 				break;
3273 			while (!isspace(*fmt) && *fmt != '%' && *fmt) {
3274 				/* '%*[' not yet supported, invalid format */
3275 				if (*fmt == '[')
3276 					return num;
3277 				fmt++;
3278 			}
3279 			while (!isspace(*str) && *str)
3280 				str++;
3281 			continue;
3282 		}
3283 
3284 		/* get field width */
3285 		field_width = -1;
3286 		if (isdigit(*fmt)) {
3287 			field_width = skip_atoi(&fmt);
3288 			if (field_width <= 0)
3289 				break;
3290 		}
3291 
3292 		/* get conversion qualifier */
3293 		qualifier = -1;
3294 		if (*fmt == 'h' || _tolower(*fmt) == 'l' ||
3295 		    *fmt == 'z') {
3296 			qualifier = *fmt++;
3297 			if (unlikely(qualifier == *fmt)) {
3298 				if (qualifier == 'h') {
3299 					qualifier = 'H';
3300 					fmt++;
3301 				} else if (qualifier == 'l') {
3302 					qualifier = 'L';
3303 					fmt++;
3304 				}
3305 			}
3306 		}
3307 
3308 		if (!*fmt)
3309 			break;
3310 
3311 		if (*fmt == 'n') {
3312 			/* return number of characters read so far */
3313 			*va_arg(args, int *) = str - buf;
3314 			++fmt;
3315 			continue;
3316 		}
3317 
3318 		if (!*str)
3319 			break;
3320 
3321 		base = 10;
3322 		is_sign = false;
3323 
3324 		switch (*fmt++) {
3325 		case 'c':
3326 		{
3327 			char *s = (char *)va_arg(args, char*);
3328 			if (field_width == -1)
3329 				field_width = 1;
3330 			do {
3331 				*s++ = *str++;
3332 			} while (--field_width > 0 && *str);
3333 			num++;
3334 		}
3335 		continue;
3336 		case 's':
3337 		{
3338 			char *s = (char *)va_arg(args, char *);
3339 			if (field_width == -1)
3340 				field_width = SHRT_MAX;
3341 			/* first, skip leading white space in buffer */
3342 			str = skip_spaces(str);
3343 
3344 			/* now copy until next white space */
3345 			while (*str && !isspace(*str) && field_width--)
3346 				*s++ = *str++;
3347 			*s = '\0';
3348 			num++;
3349 		}
3350 		continue;
3351 		/*
3352 		 * Warning: This implementation of the '[' conversion specifier
3353 		 * deviates from its glibc counterpart in the following ways:
3354 		 * (1) It does NOT support ranges i.e. '-' is NOT a special
3355 		 *     character
3356 		 * (2) It cannot match the closing bracket ']' itself
3357 		 * (3) A field width is required
3358 		 * (4) '%*[' (discard matching input) is currently not supported
3359 		 *
3360 		 * Example usage:
3361 		 * ret = sscanf("00:0a:95","%2[^:]:%2[^:]:%2[^:]",
3362 		 *		buf1, buf2, buf3);
3363 		 * if (ret < 3)
3364 		 *    // etc..
3365 		 */
3366 		case '[':
3367 		{
3368 			char *s = (char *)va_arg(args, char *);
3369 			DECLARE_BITMAP(set, 256) = {0};
3370 			unsigned int len = 0;
3371 			bool negate = (*fmt == '^');
3372 
3373 			/* field width is required */
3374 			if (field_width == -1)
3375 				return num;
3376 
3377 			if (negate)
3378 				++fmt;
3379 
3380 			for ( ; *fmt && *fmt != ']'; ++fmt, ++len)
3381 				set_bit((u8)*fmt, set);
3382 
3383 			/* no ']' or no character set found */
3384 			if (!*fmt || !len)
3385 				return num;
3386 			++fmt;
3387 
3388 			if (negate) {
3389 				bitmap_complement(set, set, 256);
3390 				/* exclude null '\0' byte */
3391 				clear_bit(0, set);
3392 			}
3393 
3394 			/* match must be non-empty */
3395 			if (!test_bit((u8)*str, set))
3396 				return num;
3397 
3398 			while (test_bit((u8)*str, set) && field_width--)
3399 				*s++ = *str++;
3400 			*s = '\0';
3401 			++num;
3402 		}
3403 		continue;
3404 		case 'o':
3405 			base = 8;
3406 			break;
3407 		case 'x':
3408 		case 'X':
3409 			base = 16;
3410 			break;
3411 		case 'i':
3412 			base = 0;
3413 			/* fall through */
3414 		case 'd':
3415 			is_sign = true;
3416 			/* fall through */
3417 		case 'u':
3418 			break;
3419 		case '%':
3420 			/* looking for '%' in str */
3421 			if (*str++ != '%')
3422 				return num;
3423 			continue;
3424 		default:
3425 			/* invalid format; stop here */
3426 			return num;
3427 		}
3428 
3429 		/* have some sort of integer conversion.
3430 		 * first, skip white space in buffer.
3431 		 */
3432 		str = skip_spaces(str);
3433 
3434 		digit = *str;
3435 		if (is_sign && digit == '-')
3436 			digit = *(str + 1);
3437 
3438 		if (!digit
3439 		    || (base == 16 && !isxdigit(digit))
3440 		    || (base == 10 && !isdigit(digit))
3441 		    || (base == 8 && (!isdigit(digit) || digit > '7'))
3442 		    || (base == 0 && !isdigit(digit)))
3443 			break;
3444 
3445 		if (is_sign)
3446 			val.s = qualifier != 'L' ?
3447 				simple_strtol(str, &next, base) :
3448 				simple_strtoll(str, &next, base);
3449 		else
3450 			val.u = qualifier != 'L' ?
3451 				simple_strtoul(str, &next, base) :
3452 				simple_strtoull(str, &next, base);
3453 
3454 		if (field_width > 0 && next - str > field_width) {
3455 			if (base == 0)
3456 				_parse_integer_fixup_radix(str, &base);
3457 			while (next - str > field_width) {
3458 				if (is_sign)
3459 					val.s = div_s64(val.s, base);
3460 				else
3461 					val.u = div_u64(val.u, base);
3462 				--next;
3463 			}
3464 		}
3465 
3466 		switch (qualifier) {
3467 		case 'H':	/* that's 'hh' in format */
3468 			if (is_sign)
3469 				*va_arg(args, signed char *) = val.s;
3470 			else
3471 				*va_arg(args, unsigned char *) = val.u;
3472 			break;
3473 		case 'h':
3474 			if (is_sign)
3475 				*va_arg(args, short *) = val.s;
3476 			else
3477 				*va_arg(args, unsigned short *) = val.u;
3478 			break;
3479 		case 'l':
3480 			if (is_sign)
3481 				*va_arg(args, long *) = val.s;
3482 			else
3483 				*va_arg(args, unsigned long *) = val.u;
3484 			break;
3485 		case 'L':
3486 			if (is_sign)
3487 				*va_arg(args, long long *) = val.s;
3488 			else
3489 				*va_arg(args, unsigned long long *) = val.u;
3490 			break;
3491 		case 'z':
3492 			*va_arg(args, size_t *) = val.u;
3493 			break;
3494 		default:
3495 			if (is_sign)
3496 				*va_arg(args, int *) = val.s;
3497 			else
3498 				*va_arg(args, unsigned int *) = val.u;
3499 			break;
3500 		}
3501 		num++;
3502 
3503 		if (!next)
3504 			break;
3505 		str = next;
3506 	}
3507 
3508 	return num;
3509 }
3510 EXPORT_SYMBOL(vsscanf);
3511 
3512 /**
3513  * sscanf - Unformat a buffer into a list of arguments
3514  * @buf:	input buffer
3515  * @fmt:	formatting of buffer
3516  * @...:	resulting arguments
3517  */
3518 int sscanf(const char *buf, const char *fmt, ...)
3519 {
3520 	va_list args;
3521 	int i;
3522 
3523 	va_start(args, fmt);
3524 	i = vsscanf(buf, fmt, args);
3525 	va_end(args);
3526 
3527 	return i;
3528 }
3529 EXPORT_SYMBOL(sscanf);
3530