xref: /openbmc/linux/lib/vsprintf.c (revision afb46f79)
1 /*
2  *  linux/lib/vsprintf.c
3  *
4  *  Copyright (C) 1991, 1992  Linus Torvalds
5  */
6 
7 /* vsprintf.c -- Lars Wirzenius & Linus Torvalds. */
8 /*
9  * Wirzenius wrote this portably, Torvalds fucked it up :-)
10  */
11 
12 /*
13  * Fri Jul 13 2001 Crutcher Dunnavant <crutcher+kernel@datastacks.com>
14  * - changed to provide snprintf and vsnprintf functions
15  * So Feb  1 16:51:32 CET 2004 Juergen Quade <quade@hsnr.de>
16  * - scnprintf and vscnprintf
17  */
18 
19 #include <stdarg.h>
20 #include <linux/module.h>	/* for KSYM_SYMBOL_LEN */
21 #include <linux/types.h>
22 #include <linux/string.h>
23 #include <linux/ctype.h>
24 #include <linux/kernel.h>
25 #include <linux/kallsyms.h>
26 #include <linux/math64.h>
27 #include <linux/uaccess.h>
28 #include <linux/ioport.h>
29 #include <linux/dcache.h>
30 #include <linux/cred.h>
31 #include <net/addrconf.h>
32 
33 #include <asm/page.h>		/* for PAGE_SIZE */
34 #include <asm/sections.h>	/* for dereference_function_descriptor() */
35 
36 #include "kstrtox.h"
37 
38 /**
39  * simple_strtoull - convert a string to an unsigned long long
40  * @cp: The start of the string
41  * @endp: A pointer to the end of the parsed string will be placed here
42  * @base: The number base to use
43  *
44  * This function is obsolete. Please use kstrtoull instead.
45  */
46 unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base)
47 {
48 	unsigned long long result;
49 	unsigned int rv;
50 
51 	cp = _parse_integer_fixup_radix(cp, &base);
52 	rv = _parse_integer(cp, base, &result);
53 	/* FIXME */
54 	cp += (rv & ~KSTRTOX_OVERFLOW);
55 
56 	if (endp)
57 		*endp = (char *)cp;
58 
59 	return result;
60 }
61 EXPORT_SYMBOL(simple_strtoull);
62 
63 /**
64  * simple_strtoul - convert a string to an unsigned long
65  * @cp: The start of the string
66  * @endp: A pointer to the end of the parsed string will be placed here
67  * @base: The number base to use
68  *
69  * This function is obsolete. Please use kstrtoul instead.
70  */
71 unsigned long simple_strtoul(const char *cp, char **endp, unsigned int base)
72 {
73 	return simple_strtoull(cp, endp, base);
74 }
75 EXPORT_SYMBOL(simple_strtoul);
76 
77 /**
78  * simple_strtol - convert a string to a signed long
79  * @cp: The start of the string
80  * @endp: A pointer to the end of the parsed string will be placed here
81  * @base: The number base to use
82  *
83  * This function is obsolete. Please use kstrtol instead.
84  */
85 long simple_strtol(const char *cp, char **endp, unsigned int base)
86 {
87 	if (*cp == '-')
88 		return -simple_strtoul(cp + 1, endp, base);
89 
90 	return simple_strtoul(cp, endp, base);
91 }
92 EXPORT_SYMBOL(simple_strtol);
93 
94 /**
95  * simple_strtoll - convert a string to a signed long long
96  * @cp: The start of the string
97  * @endp: A pointer to the end of the parsed string will be placed here
98  * @base: The number base to use
99  *
100  * This function is obsolete. Please use kstrtoll instead.
101  */
102 long long simple_strtoll(const char *cp, char **endp, unsigned int base)
103 {
104 	if (*cp == '-')
105 		return -simple_strtoull(cp + 1, endp, base);
106 
107 	return simple_strtoull(cp, endp, base);
108 }
109 EXPORT_SYMBOL(simple_strtoll);
110 
111 static noinline_for_stack
112 int skip_atoi(const char **s)
113 {
114 	int i = 0;
115 
116 	while (isdigit(**s))
117 		i = i*10 + *((*s)++) - '0';
118 
119 	return i;
120 }
121 
122 /* Decimal conversion is by far the most typical, and is used
123  * for /proc and /sys data. This directly impacts e.g. top performance
124  * with many processes running. We optimize it for speed
125  * using ideas described at <http://www.cs.uiowa.edu/~jones/bcd/divide.html>
126  * (with permission from the author, Douglas W. Jones).
127  */
128 
129 #if BITS_PER_LONG != 32 || BITS_PER_LONG_LONG != 64
130 /* Formats correctly any integer in [0, 999999999] */
131 static noinline_for_stack
132 char *put_dec_full9(char *buf, unsigned q)
133 {
134 	unsigned r;
135 
136 	/*
137 	 * Possible ways to approx. divide by 10
138 	 * (x * 0x1999999a) >> 32 x < 1073741829 (multiply must be 64-bit)
139 	 * (x * 0xcccd) >> 19     x <      81920 (x < 262149 when 64-bit mul)
140 	 * (x * 0x6667) >> 18     x <      43699
141 	 * (x * 0x3334) >> 17     x <      16389
142 	 * (x * 0x199a) >> 16     x <      16389
143 	 * (x * 0x0ccd) >> 15     x <      16389
144 	 * (x * 0x0667) >> 14     x <       2739
145 	 * (x * 0x0334) >> 13     x <       1029
146 	 * (x * 0x019a) >> 12     x <       1029
147 	 * (x * 0x00cd) >> 11     x <       1029 shorter code than * 0x67 (on i386)
148 	 * (x * 0x0067) >> 10     x <        179
149 	 * (x * 0x0034) >>  9     x <         69 same
150 	 * (x * 0x001a) >>  8     x <         69 same
151 	 * (x * 0x000d) >>  7     x <         69 same, shortest code (on i386)
152 	 * (x * 0x0007) >>  6     x <         19
153 	 * See <http://www.cs.uiowa.edu/~jones/bcd/divide.html>
154 	 */
155 	r      = (q * (uint64_t)0x1999999a) >> 32;
156 	*buf++ = (q - 10 * r) + '0'; /* 1 */
157 	q      = (r * (uint64_t)0x1999999a) >> 32;
158 	*buf++ = (r - 10 * q) + '0'; /* 2 */
159 	r      = (q * (uint64_t)0x1999999a) >> 32;
160 	*buf++ = (q - 10 * r) + '0'; /* 3 */
161 	q      = (r * (uint64_t)0x1999999a) >> 32;
162 	*buf++ = (r - 10 * q) + '0'; /* 4 */
163 	r      = (q * (uint64_t)0x1999999a) >> 32;
164 	*buf++ = (q - 10 * r) + '0'; /* 5 */
165 	/* Now value is under 10000, can avoid 64-bit multiply */
166 	q      = (r * 0x199a) >> 16;
167 	*buf++ = (r - 10 * q)  + '0'; /* 6 */
168 	r      = (q * 0xcd) >> 11;
169 	*buf++ = (q - 10 * r)  + '0'; /* 7 */
170 	q      = (r * 0xcd) >> 11;
171 	*buf++ = (r - 10 * q) + '0'; /* 8 */
172 	*buf++ = q + '0'; /* 9 */
173 	return buf;
174 }
175 #endif
176 
177 /* Similar to above but do not pad with zeros.
178  * Code can be easily arranged to print 9 digits too, but our callers
179  * always call put_dec_full9() instead when the number has 9 decimal digits.
180  */
181 static noinline_for_stack
182 char *put_dec_trunc8(char *buf, unsigned r)
183 {
184 	unsigned q;
185 
186 	/* Copy of previous function's body with added early returns */
187 	while (r >= 10000) {
188 		q = r + '0';
189 		r  = (r * (uint64_t)0x1999999a) >> 32;
190 		*buf++ = q - 10*r;
191 	}
192 
193 	q      = (r * 0x199a) >> 16;	/* r <= 9999 */
194 	*buf++ = (r - 10 * q)  + '0';
195 	if (q == 0)
196 		return buf;
197 	r      = (q * 0xcd) >> 11;	/* q <= 999 */
198 	*buf++ = (q - 10 * r)  + '0';
199 	if (r == 0)
200 		return buf;
201 	q      = (r * 0xcd) >> 11;	/* r <= 99 */
202 	*buf++ = (r - 10 * q) + '0';
203 	if (q == 0)
204 		return buf;
205 	*buf++ = q + '0';		 /* q <= 9 */
206 	return buf;
207 }
208 
209 /* There are two algorithms to print larger numbers.
210  * One is generic: divide by 1000000000 and repeatedly print
211  * groups of (up to) 9 digits. It's conceptually simple,
212  * but requires a (unsigned long long) / 1000000000 division.
213  *
214  * Second algorithm splits 64-bit unsigned long long into 16-bit chunks,
215  * manipulates them cleverly and generates groups of 4 decimal digits.
216  * It so happens that it does NOT require long long division.
217  *
218  * If long is > 32 bits, division of 64-bit values is relatively easy,
219  * and we will use the first algorithm.
220  * If long long is > 64 bits (strange architecture with VERY large long long),
221  * second algorithm can't be used, and we again use the first one.
222  *
223  * Else (if long is 32 bits and long long is 64 bits) we use second one.
224  */
225 
226 #if BITS_PER_LONG != 32 || BITS_PER_LONG_LONG != 64
227 
228 /* First algorithm: generic */
229 
230 static
231 char *put_dec(char *buf, unsigned long long n)
232 {
233 	if (n >= 100*1000*1000) {
234 		while (n >= 1000*1000*1000)
235 			buf = put_dec_full9(buf, do_div(n, 1000*1000*1000));
236 		if (n >= 100*1000*1000)
237 			return put_dec_full9(buf, n);
238 	}
239 	return put_dec_trunc8(buf, n);
240 }
241 
242 #else
243 
244 /* Second algorithm: valid only for 64-bit long longs */
245 
246 /* See comment in put_dec_full9 for choice of constants */
247 static noinline_for_stack
248 void put_dec_full4(char *buf, unsigned q)
249 {
250 	unsigned r;
251 	r      = (q * 0xccd) >> 15;
252 	buf[0] = (q - 10 * r) + '0';
253 	q      = (r * 0xcd) >> 11;
254 	buf[1] = (r - 10 * q)  + '0';
255 	r      = (q * 0xcd) >> 11;
256 	buf[2] = (q - 10 * r)  + '0';
257 	buf[3] = r + '0';
258 }
259 
260 /*
261  * Call put_dec_full4 on x % 10000, return x / 10000.
262  * The approximation x/10000 == (x * 0x346DC5D7) >> 43
263  * holds for all x < 1,128,869,999.  The largest value this
264  * helper will ever be asked to convert is 1,125,520,955.
265  * (d1 in the put_dec code, assuming n is all-ones).
266  */
267 static
268 unsigned put_dec_helper4(char *buf, unsigned x)
269 {
270         uint32_t q = (x * (uint64_t)0x346DC5D7) >> 43;
271 
272         put_dec_full4(buf, x - q * 10000);
273         return q;
274 }
275 
276 /* Based on code by Douglas W. Jones found at
277  * <http://www.cs.uiowa.edu/~jones/bcd/decimal.html#sixtyfour>
278  * (with permission from the author).
279  * Performs no 64-bit division and hence should be fast on 32-bit machines.
280  */
281 static
282 char *put_dec(char *buf, unsigned long long n)
283 {
284 	uint32_t d3, d2, d1, q, h;
285 
286 	if (n < 100*1000*1000)
287 		return put_dec_trunc8(buf, n);
288 
289 	d1  = ((uint32_t)n >> 16); /* implicit "& 0xffff" */
290 	h   = (n >> 32);
291 	d2  = (h      ) & 0xffff;
292 	d3  = (h >> 16); /* implicit "& 0xffff" */
293 
294 	q   = 656 * d3 + 7296 * d2 + 5536 * d1 + ((uint32_t)n & 0xffff);
295 	q = put_dec_helper4(buf, q);
296 
297 	q += 7671 * d3 + 9496 * d2 + 6 * d1;
298 	q = put_dec_helper4(buf+4, q);
299 
300 	q += 4749 * d3 + 42 * d2;
301 	q = put_dec_helper4(buf+8, q);
302 
303 	q += 281 * d3;
304 	buf += 12;
305 	if (q)
306 		buf = put_dec_trunc8(buf, q);
307 	else while (buf[-1] == '0')
308 		--buf;
309 
310 	return buf;
311 }
312 
313 #endif
314 
315 /*
316  * Convert passed number to decimal string.
317  * Returns the length of string.  On buffer overflow, returns 0.
318  *
319  * If speed is not important, use snprintf(). It's easy to read the code.
320  */
321 int num_to_str(char *buf, int size, unsigned long long num)
322 {
323 	char tmp[sizeof(num) * 3];
324 	int idx, len;
325 
326 	/* put_dec() may work incorrectly for num = 0 (generate "", not "0") */
327 	if (num <= 9) {
328 		tmp[0] = '0' + num;
329 		len = 1;
330 	} else {
331 		len = put_dec(tmp, num) - tmp;
332 	}
333 
334 	if (len > size)
335 		return 0;
336 	for (idx = 0; idx < len; ++idx)
337 		buf[idx] = tmp[len - idx - 1];
338 	return len;
339 }
340 
341 #define ZEROPAD	1		/* pad with zero */
342 #define SIGN	2		/* unsigned/signed long */
343 #define PLUS	4		/* show plus */
344 #define SPACE	8		/* space if plus */
345 #define LEFT	16		/* left justified */
346 #define SMALL	32		/* use lowercase in hex (must be 32 == 0x20) */
347 #define SPECIAL	64		/* prefix hex with "0x", octal with "0" */
348 
349 enum format_type {
350 	FORMAT_TYPE_NONE, /* Just a string part */
351 	FORMAT_TYPE_WIDTH,
352 	FORMAT_TYPE_PRECISION,
353 	FORMAT_TYPE_CHAR,
354 	FORMAT_TYPE_STR,
355 	FORMAT_TYPE_PTR,
356 	FORMAT_TYPE_PERCENT_CHAR,
357 	FORMAT_TYPE_INVALID,
358 	FORMAT_TYPE_LONG_LONG,
359 	FORMAT_TYPE_ULONG,
360 	FORMAT_TYPE_LONG,
361 	FORMAT_TYPE_UBYTE,
362 	FORMAT_TYPE_BYTE,
363 	FORMAT_TYPE_USHORT,
364 	FORMAT_TYPE_SHORT,
365 	FORMAT_TYPE_UINT,
366 	FORMAT_TYPE_INT,
367 	FORMAT_TYPE_SIZE_T,
368 	FORMAT_TYPE_PTRDIFF
369 };
370 
371 struct printf_spec {
372 	u8	type;		/* format_type enum */
373 	u8	flags;		/* flags to number() */
374 	u8	base;		/* number base, 8, 10 or 16 only */
375 	u8	qualifier;	/* number qualifier, one of 'hHlLtzZ' */
376 	s16	field_width;	/* width of output field */
377 	s16	precision;	/* # of digits/chars */
378 };
379 
380 static noinline_for_stack
381 char *number(char *buf, char *end, unsigned long long num,
382 	     struct printf_spec spec)
383 {
384 	/* we are called with base 8, 10 or 16, only, thus don't need "G..."  */
385 	static const char digits[16] = "0123456789ABCDEF"; /* "GHIJKLMNOPQRSTUVWXYZ"; */
386 
387 	char tmp[66];
388 	char sign;
389 	char locase;
390 	int need_pfx = ((spec.flags & SPECIAL) && spec.base != 10);
391 	int i;
392 	bool is_zero = num == 0LL;
393 
394 	/* locase = 0 or 0x20. ORing digits or letters with 'locase'
395 	 * produces same digits or (maybe lowercased) letters */
396 	locase = (spec.flags & SMALL);
397 	if (spec.flags & LEFT)
398 		spec.flags &= ~ZEROPAD;
399 	sign = 0;
400 	if (spec.flags & SIGN) {
401 		if ((signed long long)num < 0) {
402 			sign = '-';
403 			num = -(signed long long)num;
404 			spec.field_width--;
405 		} else if (spec.flags & PLUS) {
406 			sign = '+';
407 			spec.field_width--;
408 		} else if (spec.flags & SPACE) {
409 			sign = ' ';
410 			spec.field_width--;
411 		}
412 	}
413 	if (need_pfx) {
414 		if (spec.base == 16)
415 			spec.field_width -= 2;
416 		else if (!is_zero)
417 			spec.field_width--;
418 	}
419 
420 	/* generate full string in tmp[], in reverse order */
421 	i = 0;
422 	if (num < spec.base)
423 		tmp[i++] = digits[num] | locase;
424 	/* Generic code, for any base:
425 	else do {
426 		tmp[i++] = (digits[do_div(num,base)] | locase);
427 	} while (num != 0);
428 	*/
429 	else if (spec.base != 10) { /* 8 or 16 */
430 		int mask = spec.base - 1;
431 		int shift = 3;
432 
433 		if (spec.base == 16)
434 			shift = 4;
435 		do {
436 			tmp[i++] = (digits[((unsigned char)num) & mask] | locase);
437 			num >>= shift;
438 		} while (num);
439 	} else { /* base 10 */
440 		i = put_dec(tmp, num) - tmp;
441 	}
442 
443 	/* printing 100 using %2d gives "100", not "00" */
444 	if (i > spec.precision)
445 		spec.precision = i;
446 	/* leading space padding */
447 	spec.field_width -= spec.precision;
448 	if (!(spec.flags & (ZEROPAD+LEFT))) {
449 		while (--spec.field_width >= 0) {
450 			if (buf < end)
451 				*buf = ' ';
452 			++buf;
453 		}
454 	}
455 	/* sign */
456 	if (sign) {
457 		if (buf < end)
458 			*buf = sign;
459 		++buf;
460 	}
461 	/* "0x" / "0" prefix */
462 	if (need_pfx) {
463 		if (spec.base == 16 || !is_zero) {
464 			if (buf < end)
465 				*buf = '0';
466 			++buf;
467 		}
468 		if (spec.base == 16) {
469 			if (buf < end)
470 				*buf = ('X' | locase);
471 			++buf;
472 		}
473 	}
474 	/* zero or space padding */
475 	if (!(spec.flags & LEFT)) {
476 		char c = (spec.flags & ZEROPAD) ? '0' : ' ';
477 		while (--spec.field_width >= 0) {
478 			if (buf < end)
479 				*buf = c;
480 			++buf;
481 		}
482 	}
483 	/* hmm even more zero padding? */
484 	while (i <= --spec.precision) {
485 		if (buf < end)
486 			*buf = '0';
487 		++buf;
488 	}
489 	/* actual digits of result */
490 	while (--i >= 0) {
491 		if (buf < end)
492 			*buf = tmp[i];
493 		++buf;
494 	}
495 	/* trailing space padding */
496 	while (--spec.field_width >= 0) {
497 		if (buf < end)
498 			*buf = ' ';
499 		++buf;
500 	}
501 
502 	return buf;
503 }
504 
505 static noinline_for_stack
506 char *string(char *buf, char *end, const char *s, struct printf_spec spec)
507 {
508 	int len, i;
509 
510 	if ((unsigned long)s < PAGE_SIZE)
511 		s = "(null)";
512 
513 	len = strnlen(s, spec.precision);
514 
515 	if (!(spec.flags & LEFT)) {
516 		while (len < spec.field_width--) {
517 			if (buf < end)
518 				*buf = ' ';
519 			++buf;
520 		}
521 	}
522 	for (i = 0; i < len; ++i) {
523 		if (buf < end)
524 			*buf = *s;
525 		++buf; ++s;
526 	}
527 	while (len < spec.field_width--) {
528 		if (buf < end)
529 			*buf = ' ';
530 		++buf;
531 	}
532 
533 	return buf;
534 }
535 
536 static void widen(char *buf, char *end, unsigned len, unsigned spaces)
537 {
538 	size_t size;
539 	if (buf >= end)	/* nowhere to put anything */
540 		return;
541 	size = end - buf;
542 	if (size <= spaces) {
543 		memset(buf, ' ', size);
544 		return;
545 	}
546 	if (len) {
547 		if (len > size - spaces)
548 			len = size - spaces;
549 		memmove(buf + spaces, buf, len);
550 	}
551 	memset(buf, ' ', spaces);
552 }
553 
554 static noinline_for_stack
555 char *dentry_name(char *buf, char *end, const struct dentry *d, struct printf_spec spec,
556 		  const char *fmt)
557 {
558 	const char *array[4], *s;
559 	const struct dentry *p;
560 	int depth;
561 	int i, n;
562 
563 	switch (fmt[1]) {
564 		case '2': case '3': case '4':
565 			depth = fmt[1] - '0';
566 			break;
567 		default:
568 			depth = 1;
569 	}
570 
571 	rcu_read_lock();
572 	for (i = 0; i < depth; i++, d = p) {
573 		p = ACCESS_ONCE(d->d_parent);
574 		array[i] = ACCESS_ONCE(d->d_name.name);
575 		if (p == d) {
576 			if (i)
577 				array[i] = "";
578 			i++;
579 			break;
580 		}
581 	}
582 	s = array[--i];
583 	for (n = 0; n != spec.precision; n++, buf++) {
584 		char c = *s++;
585 		if (!c) {
586 			if (!i)
587 				break;
588 			c = '/';
589 			s = array[--i];
590 		}
591 		if (buf < end)
592 			*buf = c;
593 	}
594 	rcu_read_unlock();
595 	if (n < spec.field_width) {
596 		/* we want to pad the sucker */
597 		unsigned spaces = spec.field_width - n;
598 		if (!(spec.flags & LEFT)) {
599 			widen(buf - n, end, n, spaces);
600 			return buf + spaces;
601 		}
602 		while (spaces--) {
603 			if (buf < end)
604 				*buf = ' ';
605 			++buf;
606 		}
607 	}
608 	return buf;
609 }
610 
611 static noinline_for_stack
612 char *symbol_string(char *buf, char *end, void *ptr,
613 		    struct printf_spec spec, const char *fmt)
614 {
615 	unsigned long value;
616 #ifdef CONFIG_KALLSYMS
617 	char sym[KSYM_SYMBOL_LEN];
618 #endif
619 
620 	if (fmt[1] == 'R')
621 		ptr = __builtin_extract_return_addr(ptr);
622 	value = (unsigned long)ptr;
623 
624 #ifdef CONFIG_KALLSYMS
625 	if (*fmt == 'B')
626 		sprint_backtrace(sym, value);
627 	else if (*fmt != 'f' && *fmt != 's')
628 		sprint_symbol(sym, value);
629 	else
630 		sprint_symbol_no_offset(sym, value);
631 
632 	return string(buf, end, sym, spec);
633 #else
634 	spec.field_width = 2 * sizeof(void *);
635 	spec.flags |= SPECIAL | SMALL | ZEROPAD;
636 	spec.base = 16;
637 
638 	return number(buf, end, value, spec);
639 #endif
640 }
641 
642 static noinline_for_stack
643 char *resource_string(char *buf, char *end, struct resource *res,
644 		      struct printf_spec spec, const char *fmt)
645 {
646 #ifndef IO_RSRC_PRINTK_SIZE
647 #define IO_RSRC_PRINTK_SIZE	6
648 #endif
649 
650 #ifndef MEM_RSRC_PRINTK_SIZE
651 #define MEM_RSRC_PRINTK_SIZE	10
652 #endif
653 	static const struct printf_spec io_spec = {
654 		.base = 16,
655 		.field_width = IO_RSRC_PRINTK_SIZE,
656 		.precision = -1,
657 		.flags = SPECIAL | SMALL | ZEROPAD,
658 	};
659 	static const struct printf_spec mem_spec = {
660 		.base = 16,
661 		.field_width = MEM_RSRC_PRINTK_SIZE,
662 		.precision = -1,
663 		.flags = SPECIAL | SMALL | ZEROPAD,
664 	};
665 	static const struct printf_spec bus_spec = {
666 		.base = 16,
667 		.field_width = 2,
668 		.precision = -1,
669 		.flags = SMALL | ZEROPAD,
670 	};
671 	static const struct printf_spec dec_spec = {
672 		.base = 10,
673 		.precision = -1,
674 		.flags = 0,
675 	};
676 	static const struct printf_spec str_spec = {
677 		.field_width = -1,
678 		.precision = 10,
679 		.flags = LEFT,
680 	};
681 	static const struct printf_spec flag_spec = {
682 		.base = 16,
683 		.precision = -1,
684 		.flags = SPECIAL | SMALL,
685 	};
686 
687 	/* 32-bit res (sizeof==4): 10 chars in dec, 10 in hex ("0x" + 8)
688 	 * 64-bit res (sizeof==8): 20 chars in dec, 18 in hex ("0x" + 16) */
689 #define RSRC_BUF_SIZE		((2 * sizeof(resource_size_t)) + 4)
690 #define FLAG_BUF_SIZE		(2 * sizeof(res->flags))
691 #define DECODED_BUF_SIZE	sizeof("[mem - 64bit pref window disabled]")
692 #define RAW_BUF_SIZE		sizeof("[mem - flags 0x]")
693 	char sym[max(2*RSRC_BUF_SIZE + DECODED_BUF_SIZE,
694 		     2*RSRC_BUF_SIZE + FLAG_BUF_SIZE + RAW_BUF_SIZE)];
695 
696 	char *p = sym, *pend = sym + sizeof(sym);
697 	int decode = (fmt[0] == 'R') ? 1 : 0;
698 	const struct printf_spec *specp;
699 
700 	*p++ = '[';
701 	if (res->flags & IORESOURCE_IO) {
702 		p = string(p, pend, "io  ", str_spec);
703 		specp = &io_spec;
704 	} else if (res->flags & IORESOURCE_MEM) {
705 		p = string(p, pend, "mem ", str_spec);
706 		specp = &mem_spec;
707 	} else if (res->flags & IORESOURCE_IRQ) {
708 		p = string(p, pend, "irq ", str_spec);
709 		specp = &dec_spec;
710 	} else if (res->flags & IORESOURCE_DMA) {
711 		p = string(p, pend, "dma ", str_spec);
712 		specp = &dec_spec;
713 	} else if (res->flags & IORESOURCE_BUS) {
714 		p = string(p, pend, "bus ", str_spec);
715 		specp = &bus_spec;
716 	} else {
717 		p = string(p, pend, "??? ", str_spec);
718 		specp = &mem_spec;
719 		decode = 0;
720 	}
721 	if (decode && res->flags & IORESOURCE_UNSET) {
722 		p = string(p, pend, "size ", str_spec);
723 		p = number(p, pend, resource_size(res), *specp);
724 	} else {
725 		p = number(p, pend, res->start, *specp);
726 		if (res->start != res->end) {
727 			*p++ = '-';
728 			p = number(p, pend, res->end, *specp);
729 		}
730 	}
731 	if (decode) {
732 		if (res->flags & IORESOURCE_MEM_64)
733 			p = string(p, pend, " 64bit", str_spec);
734 		if (res->flags & IORESOURCE_PREFETCH)
735 			p = string(p, pend, " pref", str_spec);
736 		if (res->flags & IORESOURCE_WINDOW)
737 			p = string(p, pend, " window", str_spec);
738 		if (res->flags & IORESOURCE_DISABLED)
739 			p = string(p, pend, " disabled", str_spec);
740 	} else {
741 		p = string(p, pend, " flags ", str_spec);
742 		p = number(p, pend, res->flags, flag_spec);
743 	}
744 	*p++ = ']';
745 	*p = '\0';
746 
747 	return string(buf, end, sym, spec);
748 }
749 
750 static noinline_for_stack
751 char *hex_string(char *buf, char *end, u8 *addr, struct printf_spec spec,
752 		 const char *fmt)
753 {
754 	int i, len = 1;		/* if we pass '%ph[CDN]', field width remains
755 				   negative value, fallback to the default */
756 	char separator;
757 
758 	if (spec.field_width == 0)
759 		/* nothing to print */
760 		return buf;
761 
762 	if (ZERO_OR_NULL_PTR(addr))
763 		/* NULL pointer */
764 		return string(buf, end, NULL, spec);
765 
766 	switch (fmt[1]) {
767 	case 'C':
768 		separator = ':';
769 		break;
770 	case 'D':
771 		separator = '-';
772 		break;
773 	case 'N':
774 		separator = 0;
775 		break;
776 	default:
777 		separator = ' ';
778 		break;
779 	}
780 
781 	if (spec.field_width > 0)
782 		len = min_t(int, spec.field_width, 64);
783 
784 	for (i = 0; i < len && buf < end - 1; i++) {
785 		buf = hex_byte_pack(buf, addr[i]);
786 
787 		if (buf < end && separator && i != len - 1)
788 			*buf++ = separator;
789 	}
790 
791 	return buf;
792 }
793 
794 static noinline_for_stack
795 char *mac_address_string(char *buf, char *end, u8 *addr,
796 			 struct printf_spec spec, const char *fmt)
797 {
798 	char mac_addr[sizeof("xx:xx:xx:xx:xx:xx")];
799 	char *p = mac_addr;
800 	int i;
801 	char separator;
802 	bool reversed = false;
803 
804 	switch (fmt[1]) {
805 	case 'F':
806 		separator = '-';
807 		break;
808 
809 	case 'R':
810 		reversed = true;
811 		/* fall through */
812 
813 	default:
814 		separator = ':';
815 		break;
816 	}
817 
818 	for (i = 0; i < 6; i++) {
819 		if (reversed)
820 			p = hex_byte_pack(p, addr[5 - i]);
821 		else
822 			p = hex_byte_pack(p, addr[i]);
823 
824 		if (fmt[0] == 'M' && i != 5)
825 			*p++ = separator;
826 	}
827 	*p = '\0';
828 
829 	return string(buf, end, mac_addr, spec);
830 }
831 
832 static noinline_for_stack
833 char *ip4_string(char *p, const u8 *addr, const char *fmt)
834 {
835 	int i;
836 	bool leading_zeros = (fmt[0] == 'i');
837 	int index;
838 	int step;
839 
840 	switch (fmt[2]) {
841 	case 'h':
842 #ifdef __BIG_ENDIAN
843 		index = 0;
844 		step = 1;
845 #else
846 		index = 3;
847 		step = -1;
848 #endif
849 		break;
850 	case 'l':
851 		index = 3;
852 		step = -1;
853 		break;
854 	case 'n':
855 	case 'b':
856 	default:
857 		index = 0;
858 		step = 1;
859 		break;
860 	}
861 	for (i = 0; i < 4; i++) {
862 		char temp[3];	/* hold each IP quad in reverse order */
863 		int digits = put_dec_trunc8(temp, addr[index]) - temp;
864 		if (leading_zeros) {
865 			if (digits < 3)
866 				*p++ = '0';
867 			if (digits < 2)
868 				*p++ = '0';
869 		}
870 		/* reverse the digits in the quad */
871 		while (digits--)
872 			*p++ = temp[digits];
873 		if (i < 3)
874 			*p++ = '.';
875 		index += step;
876 	}
877 	*p = '\0';
878 
879 	return p;
880 }
881 
882 static noinline_for_stack
883 char *ip6_compressed_string(char *p, const char *addr)
884 {
885 	int i, j, range;
886 	unsigned char zerolength[8];
887 	int longest = 1;
888 	int colonpos = -1;
889 	u16 word;
890 	u8 hi, lo;
891 	bool needcolon = false;
892 	bool useIPv4;
893 	struct in6_addr in6;
894 
895 	memcpy(&in6, addr, sizeof(struct in6_addr));
896 
897 	useIPv4 = ipv6_addr_v4mapped(&in6) || ipv6_addr_is_isatap(&in6);
898 
899 	memset(zerolength, 0, sizeof(zerolength));
900 
901 	if (useIPv4)
902 		range = 6;
903 	else
904 		range = 8;
905 
906 	/* find position of longest 0 run */
907 	for (i = 0; i < range; i++) {
908 		for (j = i; j < range; j++) {
909 			if (in6.s6_addr16[j] != 0)
910 				break;
911 			zerolength[i]++;
912 		}
913 	}
914 	for (i = 0; i < range; i++) {
915 		if (zerolength[i] > longest) {
916 			longest = zerolength[i];
917 			colonpos = i;
918 		}
919 	}
920 	if (longest == 1)		/* don't compress a single 0 */
921 		colonpos = -1;
922 
923 	/* emit address */
924 	for (i = 0; i < range; i++) {
925 		if (i == colonpos) {
926 			if (needcolon || i == 0)
927 				*p++ = ':';
928 			*p++ = ':';
929 			needcolon = false;
930 			i += longest - 1;
931 			continue;
932 		}
933 		if (needcolon) {
934 			*p++ = ':';
935 			needcolon = false;
936 		}
937 		/* hex u16 without leading 0s */
938 		word = ntohs(in6.s6_addr16[i]);
939 		hi = word >> 8;
940 		lo = word & 0xff;
941 		if (hi) {
942 			if (hi > 0x0f)
943 				p = hex_byte_pack(p, hi);
944 			else
945 				*p++ = hex_asc_lo(hi);
946 			p = hex_byte_pack(p, lo);
947 		}
948 		else if (lo > 0x0f)
949 			p = hex_byte_pack(p, lo);
950 		else
951 			*p++ = hex_asc_lo(lo);
952 		needcolon = true;
953 	}
954 
955 	if (useIPv4) {
956 		if (needcolon)
957 			*p++ = ':';
958 		p = ip4_string(p, &in6.s6_addr[12], "I4");
959 	}
960 	*p = '\0';
961 
962 	return p;
963 }
964 
965 static noinline_for_stack
966 char *ip6_string(char *p, const char *addr, const char *fmt)
967 {
968 	int i;
969 
970 	for (i = 0; i < 8; i++) {
971 		p = hex_byte_pack(p, *addr++);
972 		p = hex_byte_pack(p, *addr++);
973 		if (fmt[0] == 'I' && i != 7)
974 			*p++ = ':';
975 	}
976 	*p = '\0';
977 
978 	return p;
979 }
980 
981 static noinline_for_stack
982 char *ip6_addr_string(char *buf, char *end, const u8 *addr,
983 		      struct printf_spec spec, const char *fmt)
984 {
985 	char ip6_addr[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255")];
986 
987 	if (fmt[0] == 'I' && fmt[2] == 'c')
988 		ip6_compressed_string(ip6_addr, addr);
989 	else
990 		ip6_string(ip6_addr, addr, fmt);
991 
992 	return string(buf, end, ip6_addr, spec);
993 }
994 
995 static noinline_for_stack
996 char *ip4_addr_string(char *buf, char *end, const u8 *addr,
997 		      struct printf_spec spec, const char *fmt)
998 {
999 	char ip4_addr[sizeof("255.255.255.255")];
1000 
1001 	ip4_string(ip4_addr, addr, fmt);
1002 
1003 	return string(buf, end, ip4_addr, spec);
1004 }
1005 
1006 static noinline_for_stack
1007 char *ip6_addr_string_sa(char *buf, char *end, const struct sockaddr_in6 *sa,
1008 			 struct printf_spec spec, const char *fmt)
1009 {
1010 	bool have_p = false, have_s = false, have_f = false, have_c = false;
1011 	char ip6_addr[sizeof("[xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255]") +
1012 		      sizeof(":12345") + sizeof("/123456789") +
1013 		      sizeof("%1234567890")];
1014 	char *p = ip6_addr, *pend = ip6_addr + sizeof(ip6_addr);
1015 	const u8 *addr = (const u8 *) &sa->sin6_addr;
1016 	char fmt6[2] = { fmt[0], '6' };
1017 	u8 off = 0;
1018 
1019 	fmt++;
1020 	while (isalpha(*++fmt)) {
1021 		switch (*fmt) {
1022 		case 'p':
1023 			have_p = true;
1024 			break;
1025 		case 'f':
1026 			have_f = true;
1027 			break;
1028 		case 's':
1029 			have_s = true;
1030 			break;
1031 		case 'c':
1032 			have_c = true;
1033 			break;
1034 		}
1035 	}
1036 
1037 	if (have_p || have_s || have_f) {
1038 		*p = '[';
1039 		off = 1;
1040 	}
1041 
1042 	if (fmt6[0] == 'I' && have_c)
1043 		p = ip6_compressed_string(ip6_addr + off, addr);
1044 	else
1045 		p = ip6_string(ip6_addr + off, addr, fmt6);
1046 
1047 	if (have_p || have_s || have_f)
1048 		*p++ = ']';
1049 
1050 	if (have_p) {
1051 		*p++ = ':';
1052 		p = number(p, pend, ntohs(sa->sin6_port), spec);
1053 	}
1054 	if (have_f) {
1055 		*p++ = '/';
1056 		p = number(p, pend, ntohl(sa->sin6_flowinfo &
1057 					  IPV6_FLOWINFO_MASK), spec);
1058 	}
1059 	if (have_s) {
1060 		*p++ = '%';
1061 		p = number(p, pend, sa->sin6_scope_id, spec);
1062 	}
1063 	*p = '\0';
1064 
1065 	return string(buf, end, ip6_addr, spec);
1066 }
1067 
1068 static noinline_for_stack
1069 char *ip4_addr_string_sa(char *buf, char *end, const struct sockaddr_in *sa,
1070 			 struct printf_spec spec, const char *fmt)
1071 {
1072 	bool have_p = false;
1073 	char *p, ip4_addr[sizeof("255.255.255.255") + sizeof(":12345")];
1074 	char *pend = ip4_addr + sizeof(ip4_addr);
1075 	const u8 *addr = (const u8 *) &sa->sin_addr.s_addr;
1076 	char fmt4[3] = { fmt[0], '4', 0 };
1077 
1078 	fmt++;
1079 	while (isalpha(*++fmt)) {
1080 		switch (*fmt) {
1081 		case 'p':
1082 			have_p = true;
1083 			break;
1084 		case 'h':
1085 		case 'l':
1086 		case 'n':
1087 		case 'b':
1088 			fmt4[2] = *fmt;
1089 			break;
1090 		}
1091 	}
1092 
1093 	p = ip4_string(ip4_addr, addr, fmt4);
1094 	if (have_p) {
1095 		*p++ = ':';
1096 		p = number(p, pend, ntohs(sa->sin_port), spec);
1097 	}
1098 	*p = '\0';
1099 
1100 	return string(buf, end, ip4_addr, spec);
1101 }
1102 
1103 static noinline_for_stack
1104 char *uuid_string(char *buf, char *end, const u8 *addr,
1105 		  struct printf_spec spec, const char *fmt)
1106 {
1107 	char uuid[sizeof("xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx")];
1108 	char *p = uuid;
1109 	int i;
1110 	static const u8 be[16] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
1111 	static const u8 le[16] = {3,2,1,0,5,4,7,6,8,9,10,11,12,13,14,15};
1112 	const u8 *index = be;
1113 	bool uc = false;
1114 
1115 	switch (*(++fmt)) {
1116 	case 'L':
1117 		uc = true;		/* fall-through */
1118 	case 'l':
1119 		index = le;
1120 		break;
1121 	case 'B':
1122 		uc = true;
1123 		break;
1124 	}
1125 
1126 	for (i = 0; i < 16; i++) {
1127 		p = hex_byte_pack(p, addr[index[i]]);
1128 		switch (i) {
1129 		case 3:
1130 		case 5:
1131 		case 7:
1132 		case 9:
1133 			*p++ = '-';
1134 			break;
1135 		}
1136 	}
1137 
1138 	*p = 0;
1139 
1140 	if (uc) {
1141 		p = uuid;
1142 		do {
1143 			*p = toupper(*p);
1144 		} while (*(++p));
1145 	}
1146 
1147 	return string(buf, end, uuid, spec);
1148 }
1149 
1150 static
1151 char *netdev_feature_string(char *buf, char *end, const u8 *addr,
1152 		      struct printf_spec spec)
1153 {
1154 	spec.flags |= SPECIAL | SMALL | ZEROPAD;
1155 	if (spec.field_width == -1)
1156 		spec.field_width = 2 + 2 * sizeof(netdev_features_t);
1157 	spec.base = 16;
1158 
1159 	return number(buf, end, *(const netdev_features_t *)addr, spec);
1160 }
1161 
1162 static noinline_for_stack
1163 char *address_val(char *buf, char *end, const void *addr,
1164 		  struct printf_spec spec, const char *fmt)
1165 {
1166 	unsigned long long num;
1167 
1168 	spec.flags |= SPECIAL | SMALL | ZEROPAD;
1169 	spec.base = 16;
1170 
1171 	switch (fmt[1]) {
1172 	case 'd':
1173 		num = *(const dma_addr_t *)addr;
1174 		spec.field_width = sizeof(dma_addr_t) * 2 + 2;
1175 		break;
1176 	case 'p':
1177 	default:
1178 		num = *(const phys_addr_t *)addr;
1179 		spec.field_width = sizeof(phys_addr_t) * 2 + 2;
1180 		break;
1181 	}
1182 
1183 	return number(buf, end, num, spec);
1184 }
1185 
1186 int kptr_restrict __read_mostly;
1187 
1188 /*
1189  * Show a '%p' thing.  A kernel extension is that the '%p' is followed
1190  * by an extra set of alphanumeric characters that are extended format
1191  * specifiers.
1192  *
1193  * Right now we handle:
1194  *
1195  * - 'F' For symbolic function descriptor pointers with offset
1196  * - 'f' For simple symbolic function names without offset
1197  * - 'S' For symbolic direct pointers with offset
1198  * - 's' For symbolic direct pointers without offset
1199  * - '[FfSs]R' as above with __builtin_extract_return_addr() translation
1200  * - 'B' For backtraced symbolic direct pointers with offset
1201  * - 'R' For decoded struct resource, e.g., [mem 0x0-0x1f 64bit pref]
1202  * - 'r' For raw struct resource, e.g., [mem 0x0-0x1f flags 0x201]
1203  * - 'M' For a 6-byte MAC address, it prints the address in the
1204  *       usual colon-separated hex notation
1205  * - 'm' For a 6-byte MAC address, it prints the hex address without colons
1206  * - 'MF' For a 6-byte MAC FDDI address, it prints the address
1207  *       with a dash-separated hex notation
1208  * - '[mM]R' For a 6-byte MAC address, Reverse order (Bluetooth)
1209  * - 'I' [46] for IPv4/IPv6 addresses printed in the usual way
1210  *       IPv4 uses dot-separated decimal without leading 0's (1.2.3.4)
1211  *       IPv6 uses colon separated network-order 16 bit hex with leading 0's
1212  *       [S][pfs]
1213  *       Generic IPv4/IPv6 address (struct sockaddr *) that falls back to
1214  *       [4] or [6] and is able to print port [p], flowinfo [f], scope [s]
1215  * - 'i' [46] for 'raw' IPv4/IPv6 addresses
1216  *       IPv6 omits the colons (01020304...0f)
1217  *       IPv4 uses dot-separated decimal with leading 0's (010.123.045.006)
1218  *       [S][pfs]
1219  *       Generic IPv4/IPv6 address (struct sockaddr *) that falls back to
1220  *       [4] or [6] and is able to print port [p], flowinfo [f], scope [s]
1221  * - '[Ii][4S][hnbl]' IPv4 addresses in host, network, big or little endian order
1222  * - 'I[6S]c' for IPv6 addresses printed as specified by
1223  *       http://tools.ietf.org/html/rfc5952
1224  * - 'U' For a 16 byte UUID/GUID, it prints the UUID/GUID in the form
1225  *       "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
1226  *       Options for %pU are:
1227  *         b big endian lower case hex (default)
1228  *         B big endian UPPER case hex
1229  *         l little endian lower case hex
1230  *         L little endian UPPER case hex
1231  *           big endian output byte order is:
1232  *             [0][1][2][3]-[4][5]-[6][7]-[8][9]-[10][11][12][13][14][15]
1233  *           little endian output byte order is:
1234  *             [3][2][1][0]-[5][4]-[7][6]-[8][9]-[10][11][12][13][14][15]
1235  * - 'V' For a struct va_format which contains a format string * and va_list *,
1236  *       call vsnprintf(->format, *->va_list).
1237  *       Implements a "recursive vsnprintf".
1238  *       Do not use this feature without some mechanism to verify the
1239  *       correctness of the format string and va_list arguments.
1240  * - 'K' For a kernel pointer that should be hidden from unprivileged users
1241  * - 'NF' For a netdev_features_t
1242  * - 'h[CDN]' For a variable-length buffer, it prints it as a hex string with
1243  *            a certain separator (' ' by default):
1244  *              C colon
1245  *              D dash
1246  *              N no separator
1247  *            The maximum supported length is 64 bytes of the input. Consider
1248  *            to use print_hex_dump() for the larger input.
1249  * - 'a[pd]' For address types [p] phys_addr_t, [d] dma_addr_t and derivatives
1250  *           (default assumed to be phys_addr_t, passed by reference)
1251  * - 'd[234]' For a dentry name (optionally 2-4 last components)
1252  * - 'D[234]' Same as 'd' but for a struct file
1253  *
1254  * Note: The difference between 'S' and 'F' is that on ia64 and ppc64
1255  * function pointers are really function descriptors, which contain a
1256  * pointer to the real address.
1257  */
1258 static noinline_for_stack
1259 char *pointer(const char *fmt, char *buf, char *end, void *ptr,
1260 	      struct printf_spec spec)
1261 {
1262 	int default_width = 2 * sizeof(void *) + (spec.flags & SPECIAL ? 2 : 0);
1263 
1264 	if (!ptr && *fmt != 'K') {
1265 		/*
1266 		 * Print (null) with the same width as a pointer so it makes
1267 		 * tabular output look nice.
1268 		 */
1269 		if (spec.field_width == -1)
1270 			spec.field_width = default_width;
1271 		return string(buf, end, "(null)", spec);
1272 	}
1273 
1274 	switch (*fmt) {
1275 	case 'F':
1276 	case 'f':
1277 		ptr = dereference_function_descriptor(ptr);
1278 		/* Fallthrough */
1279 	case 'S':
1280 	case 's':
1281 	case 'B':
1282 		return symbol_string(buf, end, ptr, spec, fmt);
1283 	case 'R':
1284 	case 'r':
1285 		return resource_string(buf, end, ptr, spec, fmt);
1286 	case 'h':
1287 		return hex_string(buf, end, ptr, spec, fmt);
1288 	case 'M':			/* Colon separated: 00:01:02:03:04:05 */
1289 	case 'm':			/* Contiguous: 000102030405 */
1290 					/* [mM]F (FDDI) */
1291 					/* [mM]R (Reverse order; Bluetooth) */
1292 		return mac_address_string(buf, end, ptr, spec, fmt);
1293 	case 'I':			/* Formatted IP supported
1294 					 * 4:	1.2.3.4
1295 					 * 6:	0001:0203:...:0708
1296 					 * 6c:	1::708 or 1::1.2.3.4
1297 					 */
1298 	case 'i':			/* Contiguous:
1299 					 * 4:	001.002.003.004
1300 					 * 6:   000102...0f
1301 					 */
1302 		switch (fmt[1]) {
1303 		case '6':
1304 			return ip6_addr_string(buf, end, ptr, spec, fmt);
1305 		case '4':
1306 			return ip4_addr_string(buf, end, ptr, spec, fmt);
1307 		case 'S': {
1308 			const union {
1309 				struct sockaddr		raw;
1310 				struct sockaddr_in	v4;
1311 				struct sockaddr_in6	v6;
1312 			} *sa = ptr;
1313 
1314 			switch (sa->raw.sa_family) {
1315 			case AF_INET:
1316 				return ip4_addr_string_sa(buf, end, &sa->v4, spec, fmt);
1317 			case AF_INET6:
1318 				return ip6_addr_string_sa(buf, end, &sa->v6, spec, fmt);
1319 			default:
1320 				return string(buf, end, "(invalid address)", spec);
1321 			}}
1322 		}
1323 		break;
1324 	case 'U':
1325 		return uuid_string(buf, end, ptr, spec, fmt);
1326 	case 'V':
1327 		{
1328 			va_list va;
1329 
1330 			va_copy(va, *((struct va_format *)ptr)->va);
1331 			buf += vsnprintf(buf, end > buf ? end - buf : 0,
1332 					 ((struct va_format *)ptr)->fmt, va);
1333 			va_end(va);
1334 			return buf;
1335 		}
1336 	case 'K':
1337 		/*
1338 		 * %pK cannot be used in IRQ context because its test
1339 		 * for CAP_SYSLOG would be meaningless.
1340 		 */
1341 		if (kptr_restrict && (in_irq() || in_serving_softirq() ||
1342 				      in_nmi())) {
1343 			if (spec.field_width == -1)
1344 				spec.field_width = default_width;
1345 			return string(buf, end, "pK-error", spec);
1346 		}
1347 
1348 		switch (kptr_restrict) {
1349 		case 0:
1350 			/* Always print %pK values */
1351 			break;
1352 		case 1: {
1353 			/*
1354 			 * Only print the real pointer value if the current
1355 			 * process has CAP_SYSLOG and is running with the
1356 			 * same credentials it started with. This is because
1357 			 * access to files is checked at open() time, but %pK
1358 			 * checks permission at read() time. We don't want to
1359 			 * leak pointer values if a binary opens a file using
1360 			 * %pK and then elevates privileges before reading it.
1361 			 */
1362 			const struct cred *cred = current_cred();
1363 
1364 			if (!has_capability_noaudit(current, CAP_SYSLOG) ||
1365 			    !uid_eq(cred->euid, cred->uid) ||
1366 			    !gid_eq(cred->egid, cred->gid))
1367 				ptr = NULL;
1368 			break;
1369 		}
1370 		case 2:
1371 		default:
1372 			/* Always print 0's for %pK */
1373 			ptr = NULL;
1374 			break;
1375 		}
1376 		break;
1377 
1378 	case 'N':
1379 		switch (fmt[1]) {
1380 		case 'F':
1381 			return netdev_feature_string(buf, end, ptr, spec);
1382 		}
1383 		break;
1384 	case 'a':
1385 		return address_val(buf, end, ptr, spec, fmt);
1386 	case 'd':
1387 		return dentry_name(buf, end, ptr, spec, fmt);
1388 	case 'D':
1389 		return dentry_name(buf, end,
1390 				   ((const struct file *)ptr)->f_path.dentry,
1391 				   spec, fmt);
1392 	}
1393 	spec.flags |= SMALL;
1394 	if (spec.field_width == -1) {
1395 		spec.field_width = default_width;
1396 		spec.flags |= ZEROPAD;
1397 	}
1398 	spec.base = 16;
1399 
1400 	return number(buf, end, (unsigned long) ptr, spec);
1401 }
1402 
1403 /*
1404  * Helper function to decode printf style format.
1405  * Each call decode a token from the format and return the
1406  * number of characters read (or likely the delta where it wants
1407  * to go on the next call).
1408  * The decoded token is returned through the parameters
1409  *
1410  * 'h', 'l', or 'L' for integer fields
1411  * 'z' support added 23/7/1999 S.H.
1412  * 'z' changed to 'Z' --davidm 1/25/99
1413  * 't' added for ptrdiff_t
1414  *
1415  * @fmt: the format string
1416  * @type of the token returned
1417  * @flags: various flags such as +, -, # tokens..
1418  * @field_width: overwritten width
1419  * @base: base of the number (octal, hex, ...)
1420  * @precision: precision of a number
1421  * @qualifier: qualifier of a number (long, size_t, ...)
1422  */
1423 static noinline_for_stack
1424 int format_decode(const char *fmt, struct printf_spec *spec)
1425 {
1426 	const char *start = fmt;
1427 
1428 	/* we finished early by reading the field width */
1429 	if (spec->type == FORMAT_TYPE_WIDTH) {
1430 		if (spec->field_width < 0) {
1431 			spec->field_width = -spec->field_width;
1432 			spec->flags |= LEFT;
1433 		}
1434 		spec->type = FORMAT_TYPE_NONE;
1435 		goto precision;
1436 	}
1437 
1438 	/* we finished early by reading the precision */
1439 	if (spec->type == FORMAT_TYPE_PRECISION) {
1440 		if (spec->precision < 0)
1441 			spec->precision = 0;
1442 
1443 		spec->type = FORMAT_TYPE_NONE;
1444 		goto qualifier;
1445 	}
1446 
1447 	/* By default */
1448 	spec->type = FORMAT_TYPE_NONE;
1449 
1450 	for (; *fmt ; ++fmt) {
1451 		if (*fmt == '%')
1452 			break;
1453 	}
1454 
1455 	/* Return the current non-format string */
1456 	if (fmt != start || !*fmt)
1457 		return fmt - start;
1458 
1459 	/* Process flags */
1460 	spec->flags = 0;
1461 
1462 	while (1) { /* this also skips first '%' */
1463 		bool found = true;
1464 
1465 		++fmt;
1466 
1467 		switch (*fmt) {
1468 		case '-': spec->flags |= LEFT;    break;
1469 		case '+': spec->flags |= PLUS;    break;
1470 		case ' ': spec->flags |= SPACE;   break;
1471 		case '#': spec->flags |= SPECIAL; break;
1472 		case '0': spec->flags |= ZEROPAD; break;
1473 		default:  found = false;
1474 		}
1475 
1476 		if (!found)
1477 			break;
1478 	}
1479 
1480 	/* get field width */
1481 	spec->field_width = -1;
1482 
1483 	if (isdigit(*fmt))
1484 		spec->field_width = skip_atoi(&fmt);
1485 	else if (*fmt == '*') {
1486 		/* it's the next argument */
1487 		spec->type = FORMAT_TYPE_WIDTH;
1488 		return ++fmt - start;
1489 	}
1490 
1491 precision:
1492 	/* get the precision */
1493 	spec->precision = -1;
1494 	if (*fmt == '.') {
1495 		++fmt;
1496 		if (isdigit(*fmt)) {
1497 			spec->precision = skip_atoi(&fmt);
1498 			if (spec->precision < 0)
1499 				spec->precision = 0;
1500 		} else if (*fmt == '*') {
1501 			/* it's the next argument */
1502 			spec->type = FORMAT_TYPE_PRECISION;
1503 			return ++fmt - start;
1504 		}
1505 	}
1506 
1507 qualifier:
1508 	/* get the conversion qualifier */
1509 	spec->qualifier = -1;
1510 	if (*fmt == 'h' || _tolower(*fmt) == 'l' ||
1511 	    _tolower(*fmt) == 'z' || *fmt == 't') {
1512 		spec->qualifier = *fmt++;
1513 		if (unlikely(spec->qualifier == *fmt)) {
1514 			if (spec->qualifier == 'l') {
1515 				spec->qualifier = 'L';
1516 				++fmt;
1517 			} else if (spec->qualifier == 'h') {
1518 				spec->qualifier = 'H';
1519 				++fmt;
1520 			}
1521 		}
1522 	}
1523 
1524 	/* default base */
1525 	spec->base = 10;
1526 	switch (*fmt) {
1527 	case 'c':
1528 		spec->type = FORMAT_TYPE_CHAR;
1529 		return ++fmt - start;
1530 
1531 	case 's':
1532 		spec->type = FORMAT_TYPE_STR;
1533 		return ++fmt - start;
1534 
1535 	case 'p':
1536 		spec->type = FORMAT_TYPE_PTR;
1537 		return fmt - start;
1538 		/* skip alnum */
1539 
1540 	case '%':
1541 		spec->type = FORMAT_TYPE_PERCENT_CHAR;
1542 		return ++fmt - start;
1543 
1544 	/* integer number formats - set up the flags and "break" */
1545 	case 'o':
1546 		spec->base = 8;
1547 		break;
1548 
1549 	case 'x':
1550 		spec->flags |= SMALL;
1551 
1552 	case 'X':
1553 		spec->base = 16;
1554 		break;
1555 
1556 	case 'd':
1557 	case 'i':
1558 		spec->flags |= SIGN;
1559 	case 'u':
1560 		break;
1561 
1562 	case 'n':
1563 		/*
1564 		 * Since %n poses a greater security risk than utility, treat
1565 		 * it as an invalid format specifier. Warn about its use so
1566 		 * that new instances don't get added.
1567 		 */
1568 		WARN_ONCE(1, "Please remove ignored %%n in '%s'\n", fmt);
1569 		/* Fall-through */
1570 
1571 	default:
1572 		spec->type = FORMAT_TYPE_INVALID;
1573 		return fmt - start;
1574 	}
1575 
1576 	if (spec->qualifier == 'L')
1577 		spec->type = FORMAT_TYPE_LONG_LONG;
1578 	else if (spec->qualifier == 'l') {
1579 		if (spec->flags & SIGN)
1580 			spec->type = FORMAT_TYPE_LONG;
1581 		else
1582 			spec->type = FORMAT_TYPE_ULONG;
1583 	} else if (_tolower(spec->qualifier) == 'z') {
1584 		spec->type = FORMAT_TYPE_SIZE_T;
1585 	} else if (spec->qualifier == 't') {
1586 		spec->type = FORMAT_TYPE_PTRDIFF;
1587 	} else if (spec->qualifier == 'H') {
1588 		if (spec->flags & SIGN)
1589 			spec->type = FORMAT_TYPE_BYTE;
1590 		else
1591 			spec->type = FORMAT_TYPE_UBYTE;
1592 	} else if (spec->qualifier == 'h') {
1593 		if (spec->flags & SIGN)
1594 			spec->type = FORMAT_TYPE_SHORT;
1595 		else
1596 			spec->type = FORMAT_TYPE_USHORT;
1597 	} else {
1598 		if (spec->flags & SIGN)
1599 			spec->type = FORMAT_TYPE_INT;
1600 		else
1601 			spec->type = FORMAT_TYPE_UINT;
1602 	}
1603 
1604 	return ++fmt - start;
1605 }
1606 
1607 /**
1608  * vsnprintf - Format a string and place it in a buffer
1609  * @buf: The buffer to place the result into
1610  * @size: The size of the buffer, including the trailing null space
1611  * @fmt: The format string to use
1612  * @args: Arguments for the format string
1613  *
1614  * This function follows C99 vsnprintf, but has some extensions:
1615  * %pS output the name of a text symbol with offset
1616  * %ps output the name of a text symbol without offset
1617  * %pF output the name of a function pointer with its offset
1618  * %pf output the name of a function pointer without its offset
1619  * %pB output the name of a backtrace symbol with its offset
1620  * %pR output the address range in a struct resource with decoded flags
1621  * %pr output the address range in a struct resource with raw flags
1622  * %pM output a 6-byte MAC address with colons
1623  * %pMR output a 6-byte MAC address with colons in reversed order
1624  * %pMF output a 6-byte MAC address with dashes
1625  * %pm output a 6-byte MAC address without colons
1626  * %pmR output a 6-byte MAC address without colons in reversed order
1627  * %pI4 print an IPv4 address without leading zeros
1628  * %pi4 print an IPv4 address with leading zeros
1629  * %pI6 print an IPv6 address with colons
1630  * %pi6 print an IPv6 address without colons
1631  * %pI6c print an IPv6 address as specified by RFC 5952
1632  * %pIS depending on sa_family of 'struct sockaddr *' print IPv4/IPv6 address
1633  * %piS depending on sa_family of 'struct sockaddr *' print IPv4/IPv6 address
1634  * %pU[bBlL] print a UUID/GUID in big or little endian using lower or upper
1635  *   case.
1636  * %*ph[CDN] a variable-length hex string with a separator (supports up to 64
1637  *           bytes of the input)
1638  * %n is ignored
1639  *
1640  * ** Please update Documentation/printk-formats.txt when making changes **
1641  *
1642  * The return value is the number of characters which would
1643  * be generated for the given input, excluding the trailing
1644  * '\0', as per ISO C99. If you want to have the exact
1645  * number of characters written into @buf as return value
1646  * (not including the trailing '\0'), use vscnprintf(). If the
1647  * return is greater than or equal to @size, the resulting
1648  * string is truncated.
1649  *
1650  * If you're not already dealing with a va_list consider using snprintf().
1651  */
1652 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
1653 {
1654 	unsigned long long num;
1655 	char *str, *end;
1656 	struct printf_spec spec = {0};
1657 
1658 	/* Reject out-of-range values early.  Large positive sizes are
1659 	   used for unknown buffer sizes. */
1660 	if (WARN_ON_ONCE((int) size < 0))
1661 		return 0;
1662 
1663 	str = buf;
1664 	end = buf + size;
1665 
1666 	/* Make sure end is always >= buf */
1667 	if (end < buf) {
1668 		end = ((void *)-1);
1669 		size = end - buf;
1670 	}
1671 
1672 	while (*fmt) {
1673 		const char *old_fmt = fmt;
1674 		int read = format_decode(fmt, &spec);
1675 
1676 		fmt += read;
1677 
1678 		switch (spec.type) {
1679 		case FORMAT_TYPE_NONE: {
1680 			int copy = read;
1681 			if (str < end) {
1682 				if (copy > end - str)
1683 					copy = end - str;
1684 				memcpy(str, old_fmt, copy);
1685 			}
1686 			str += read;
1687 			break;
1688 		}
1689 
1690 		case FORMAT_TYPE_WIDTH:
1691 			spec.field_width = va_arg(args, int);
1692 			break;
1693 
1694 		case FORMAT_TYPE_PRECISION:
1695 			spec.precision = va_arg(args, int);
1696 			break;
1697 
1698 		case FORMAT_TYPE_CHAR: {
1699 			char c;
1700 
1701 			if (!(spec.flags & LEFT)) {
1702 				while (--spec.field_width > 0) {
1703 					if (str < end)
1704 						*str = ' ';
1705 					++str;
1706 
1707 				}
1708 			}
1709 			c = (unsigned char) va_arg(args, int);
1710 			if (str < end)
1711 				*str = c;
1712 			++str;
1713 			while (--spec.field_width > 0) {
1714 				if (str < end)
1715 					*str = ' ';
1716 				++str;
1717 			}
1718 			break;
1719 		}
1720 
1721 		case FORMAT_TYPE_STR:
1722 			str = string(str, end, va_arg(args, char *), spec);
1723 			break;
1724 
1725 		case FORMAT_TYPE_PTR:
1726 			str = pointer(fmt+1, str, end, va_arg(args, void *),
1727 				      spec);
1728 			while (isalnum(*fmt))
1729 				fmt++;
1730 			break;
1731 
1732 		case FORMAT_TYPE_PERCENT_CHAR:
1733 			if (str < end)
1734 				*str = '%';
1735 			++str;
1736 			break;
1737 
1738 		case FORMAT_TYPE_INVALID:
1739 			if (str < end)
1740 				*str = '%';
1741 			++str;
1742 			break;
1743 
1744 		default:
1745 			switch (spec.type) {
1746 			case FORMAT_TYPE_LONG_LONG:
1747 				num = va_arg(args, long long);
1748 				break;
1749 			case FORMAT_TYPE_ULONG:
1750 				num = va_arg(args, unsigned long);
1751 				break;
1752 			case FORMAT_TYPE_LONG:
1753 				num = va_arg(args, long);
1754 				break;
1755 			case FORMAT_TYPE_SIZE_T:
1756 				if (spec.flags & SIGN)
1757 					num = va_arg(args, ssize_t);
1758 				else
1759 					num = va_arg(args, size_t);
1760 				break;
1761 			case FORMAT_TYPE_PTRDIFF:
1762 				num = va_arg(args, ptrdiff_t);
1763 				break;
1764 			case FORMAT_TYPE_UBYTE:
1765 				num = (unsigned char) va_arg(args, int);
1766 				break;
1767 			case FORMAT_TYPE_BYTE:
1768 				num = (signed char) va_arg(args, int);
1769 				break;
1770 			case FORMAT_TYPE_USHORT:
1771 				num = (unsigned short) va_arg(args, int);
1772 				break;
1773 			case FORMAT_TYPE_SHORT:
1774 				num = (short) va_arg(args, int);
1775 				break;
1776 			case FORMAT_TYPE_INT:
1777 				num = (int) va_arg(args, int);
1778 				break;
1779 			default:
1780 				num = va_arg(args, unsigned int);
1781 			}
1782 
1783 			str = number(str, end, num, spec);
1784 		}
1785 	}
1786 
1787 	if (size > 0) {
1788 		if (str < end)
1789 			*str = '\0';
1790 		else
1791 			end[-1] = '\0';
1792 	}
1793 
1794 	/* the trailing null byte doesn't count towards the total */
1795 	return str-buf;
1796 
1797 }
1798 EXPORT_SYMBOL(vsnprintf);
1799 
1800 /**
1801  * vscnprintf - Format a string and place it in a buffer
1802  * @buf: The buffer to place the result into
1803  * @size: The size of the buffer, including the trailing null space
1804  * @fmt: The format string to use
1805  * @args: Arguments for the format string
1806  *
1807  * The return value is the number of characters which have been written into
1808  * the @buf not including the trailing '\0'. If @size is == 0 the function
1809  * returns 0.
1810  *
1811  * If you're not already dealing with a va_list consider using scnprintf().
1812  *
1813  * See the vsnprintf() documentation for format string extensions over C99.
1814  */
1815 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
1816 {
1817 	int i;
1818 
1819 	i = vsnprintf(buf, size, fmt, args);
1820 
1821 	if (likely(i < size))
1822 		return i;
1823 	if (size != 0)
1824 		return size - 1;
1825 	return 0;
1826 }
1827 EXPORT_SYMBOL(vscnprintf);
1828 
1829 /**
1830  * snprintf - Format a string and place it in a buffer
1831  * @buf: The buffer to place the result into
1832  * @size: The size of the buffer, including the trailing null space
1833  * @fmt: The format string to use
1834  * @...: Arguments for the format string
1835  *
1836  * The return value is the number of characters which would be
1837  * generated for the given input, excluding the trailing null,
1838  * as per ISO C99.  If the return is greater than or equal to
1839  * @size, the resulting string is truncated.
1840  *
1841  * See the vsnprintf() documentation for format string extensions over C99.
1842  */
1843 int snprintf(char *buf, size_t size, const char *fmt, ...)
1844 {
1845 	va_list args;
1846 	int i;
1847 
1848 	va_start(args, fmt);
1849 	i = vsnprintf(buf, size, fmt, args);
1850 	va_end(args);
1851 
1852 	return i;
1853 }
1854 EXPORT_SYMBOL(snprintf);
1855 
1856 /**
1857  * scnprintf - Format a string and place it in a buffer
1858  * @buf: The buffer to place the result into
1859  * @size: The size of the buffer, including the trailing null space
1860  * @fmt: The format string to use
1861  * @...: Arguments for the format string
1862  *
1863  * The return value is the number of characters written into @buf not including
1864  * the trailing '\0'. If @size is == 0 the function returns 0.
1865  */
1866 
1867 int scnprintf(char *buf, size_t size, const char *fmt, ...)
1868 {
1869 	va_list args;
1870 	int i;
1871 
1872 	va_start(args, fmt);
1873 	i = vscnprintf(buf, size, fmt, args);
1874 	va_end(args);
1875 
1876 	return i;
1877 }
1878 EXPORT_SYMBOL(scnprintf);
1879 
1880 /**
1881  * vsprintf - Format a string and place it in a buffer
1882  * @buf: The buffer to place the result into
1883  * @fmt: The format string to use
1884  * @args: Arguments for the format string
1885  *
1886  * The function returns the number of characters written
1887  * into @buf. Use vsnprintf() or vscnprintf() in order to avoid
1888  * buffer overflows.
1889  *
1890  * If you're not already dealing with a va_list consider using sprintf().
1891  *
1892  * See the vsnprintf() documentation for format string extensions over C99.
1893  */
1894 int vsprintf(char *buf, const char *fmt, va_list args)
1895 {
1896 	return vsnprintf(buf, INT_MAX, fmt, args);
1897 }
1898 EXPORT_SYMBOL(vsprintf);
1899 
1900 /**
1901  * sprintf - Format a string and place it in a buffer
1902  * @buf: The buffer to place the result into
1903  * @fmt: The format string to use
1904  * @...: Arguments for the format string
1905  *
1906  * The function returns the number of characters written
1907  * into @buf. Use snprintf() or scnprintf() in order to avoid
1908  * buffer overflows.
1909  *
1910  * See the vsnprintf() documentation for format string extensions over C99.
1911  */
1912 int sprintf(char *buf, const char *fmt, ...)
1913 {
1914 	va_list args;
1915 	int i;
1916 
1917 	va_start(args, fmt);
1918 	i = vsnprintf(buf, INT_MAX, fmt, args);
1919 	va_end(args);
1920 
1921 	return i;
1922 }
1923 EXPORT_SYMBOL(sprintf);
1924 
1925 #ifdef CONFIG_BINARY_PRINTF
1926 /*
1927  * bprintf service:
1928  * vbin_printf() - VA arguments to binary data
1929  * bstr_printf() - Binary data to text string
1930  */
1931 
1932 /**
1933  * vbin_printf - Parse a format string and place args' binary value in a buffer
1934  * @bin_buf: The buffer to place args' binary value
1935  * @size: The size of the buffer(by words(32bits), not characters)
1936  * @fmt: The format string to use
1937  * @args: Arguments for the format string
1938  *
1939  * The format follows C99 vsnprintf, except %n is ignored, and its argument
1940  * is skiped.
1941  *
1942  * The return value is the number of words(32bits) which would be generated for
1943  * the given input.
1944  *
1945  * NOTE:
1946  * If the return value is greater than @size, the resulting bin_buf is NOT
1947  * valid for bstr_printf().
1948  */
1949 int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args)
1950 {
1951 	struct printf_spec spec = {0};
1952 	char *str, *end;
1953 
1954 	str = (char *)bin_buf;
1955 	end = (char *)(bin_buf + size);
1956 
1957 #define save_arg(type)							\
1958 do {									\
1959 	if (sizeof(type) == 8) {					\
1960 		unsigned long long value;				\
1961 		str = PTR_ALIGN(str, sizeof(u32));			\
1962 		value = va_arg(args, unsigned long long);		\
1963 		if (str + sizeof(type) <= end) {			\
1964 			*(u32 *)str = *(u32 *)&value;			\
1965 			*(u32 *)(str + 4) = *((u32 *)&value + 1);	\
1966 		}							\
1967 	} else {							\
1968 		unsigned long value;					\
1969 		str = PTR_ALIGN(str, sizeof(type));			\
1970 		value = va_arg(args, int);				\
1971 		if (str + sizeof(type) <= end)				\
1972 			*(typeof(type) *)str = (type)value;		\
1973 	}								\
1974 	str += sizeof(type);						\
1975 } while (0)
1976 
1977 	while (*fmt) {
1978 		int read = format_decode(fmt, &spec);
1979 
1980 		fmt += read;
1981 
1982 		switch (spec.type) {
1983 		case FORMAT_TYPE_NONE:
1984 		case FORMAT_TYPE_INVALID:
1985 		case FORMAT_TYPE_PERCENT_CHAR:
1986 			break;
1987 
1988 		case FORMAT_TYPE_WIDTH:
1989 		case FORMAT_TYPE_PRECISION:
1990 			save_arg(int);
1991 			break;
1992 
1993 		case FORMAT_TYPE_CHAR:
1994 			save_arg(char);
1995 			break;
1996 
1997 		case FORMAT_TYPE_STR: {
1998 			const char *save_str = va_arg(args, char *);
1999 			size_t len;
2000 
2001 			if ((unsigned long)save_str > (unsigned long)-PAGE_SIZE
2002 					|| (unsigned long)save_str < PAGE_SIZE)
2003 				save_str = "(null)";
2004 			len = strlen(save_str) + 1;
2005 			if (str + len < end)
2006 				memcpy(str, save_str, len);
2007 			str += len;
2008 			break;
2009 		}
2010 
2011 		case FORMAT_TYPE_PTR:
2012 			save_arg(void *);
2013 			/* skip all alphanumeric pointer suffixes */
2014 			while (isalnum(*fmt))
2015 				fmt++;
2016 			break;
2017 
2018 		default:
2019 			switch (spec.type) {
2020 
2021 			case FORMAT_TYPE_LONG_LONG:
2022 				save_arg(long long);
2023 				break;
2024 			case FORMAT_TYPE_ULONG:
2025 			case FORMAT_TYPE_LONG:
2026 				save_arg(unsigned long);
2027 				break;
2028 			case FORMAT_TYPE_SIZE_T:
2029 				save_arg(size_t);
2030 				break;
2031 			case FORMAT_TYPE_PTRDIFF:
2032 				save_arg(ptrdiff_t);
2033 				break;
2034 			case FORMAT_TYPE_UBYTE:
2035 			case FORMAT_TYPE_BYTE:
2036 				save_arg(char);
2037 				break;
2038 			case FORMAT_TYPE_USHORT:
2039 			case FORMAT_TYPE_SHORT:
2040 				save_arg(short);
2041 				break;
2042 			default:
2043 				save_arg(int);
2044 			}
2045 		}
2046 	}
2047 
2048 	return (u32 *)(PTR_ALIGN(str, sizeof(u32))) - bin_buf;
2049 #undef save_arg
2050 }
2051 EXPORT_SYMBOL_GPL(vbin_printf);
2052 
2053 /**
2054  * bstr_printf - Format a string from binary arguments and place it in a buffer
2055  * @buf: The buffer to place the result into
2056  * @size: The size of the buffer, including the trailing null space
2057  * @fmt: The format string to use
2058  * @bin_buf: Binary arguments for the format string
2059  *
2060  * This function like C99 vsnprintf, but the difference is that vsnprintf gets
2061  * arguments from stack, and bstr_printf gets arguments from @bin_buf which is
2062  * a binary buffer that generated by vbin_printf.
2063  *
2064  * The format follows C99 vsnprintf, but has some extensions:
2065  *  see vsnprintf comment for details.
2066  *
2067  * The return value is the number of characters which would
2068  * be generated for the given input, excluding the trailing
2069  * '\0', as per ISO C99. If you want to have the exact
2070  * number of characters written into @buf as return value
2071  * (not including the trailing '\0'), use vscnprintf(). If the
2072  * return is greater than or equal to @size, the resulting
2073  * string is truncated.
2074  */
2075 int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf)
2076 {
2077 	struct printf_spec spec = {0};
2078 	char *str, *end;
2079 	const char *args = (const char *)bin_buf;
2080 
2081 	if (WARN_ON_ONCE((int) size < 0))
2082 		return 0;
2083 
2084 	str = buf;
2085 	end = buf + size;
2086 
2087 #define get_arg(type)							\
2088 ({									\
2089 	typeof(type) value;						\
2090 	if (sizeof(type) == 8) {					\
2091 		args = PTR_ALIGN(args, sizeof(u32));			\
2092 		*(u32 *)&value = *(u32 *)args;				\
2093 		*((u32 *)&value + 1) = *(u32 *)(args + 4);		\
2094 	} else {							\
2095 		args = PTR_ALIGN(args, sizeof(type));			\
2096 		value = *(typeof(type) *)args;				\
2097 	}								\
2098 	args += sizeof(type);						\
2099 	value;								\
2100 })
2101 
2102 	/* Make sure end is always >= buf */
2103 	if (end < buf) {
2104 		end = ((void *)-1);
2105 		size = end - buf;
2106 	}
2107 
2108 	while (*fmt) {
2109 		const char *old_fmt = fmt;
2110 		int read = format_decode(fmt, &spec);
2111 
2112 		fmt += read;
2113 
2114 		switch (spec.type) {
2115 		case FORMAT_TYPE_NONE: {
2116 			int copy = read;
2117 			if (str < end) {
2118 				if (copy > end - str)
2119 					copy = end - str;
2120 				memcpy(str, old_fmt, copy);
2121 			}
2122 			str += read;
2123 			break;
2124 		}
2125 
2126 		case FORMAT_TYPE_WIDTH:
2127 			spec.field_width = get_arg(int);
2128 			break;
2129 
2130 		case FORMAT_TYPE_PRECISION:
2131 			spec.precision = get_arg(int);
2132 			break;
2133 
2134 		case FORMAT_TYPE_CHAR: {
2135 			char c;
2136 
2137 			if (!(spec.flags & LEFT)) {
2138 				while (--spec.field_width > 0) {
2139 					if (str < end)
2140 						*str = ' ';
2141 					++str;
2142 				}
2143 			}
2144 			c = (unsigned char) get_arg(char);
2145 			if (str < end)
2146 				*str = c;
2147 			++str;
2148 			while (--spec.field_width > 0) {
2149 				if (str < end)
2150 					*str = ' ';
2151 				++str;
2152 			}
2153 			break;
2154 		}
2155 
2156 		case FORMAT_TYPE_STR: {
2157 			const char *str_arg = args;
2158 			args += strlen(str_arg) + 1;
2159 			str = string(str, end, (char *)str_arg, spec);
2160 			break;
2161 		}
2162 
2163 		case FORMAT_TYPE_PTR:
2164 			str = pointer(fmt+1, str, end, get_arg(void *), spec);
2165 			while (isalnum(*fmt))
2166 				fmt++;
2167 			break;
2168 
2169 		case FORMAT_TYPE_PERCENT_CHAR:
2170 		case FORMAT_TYPE_INVALID:
2171 			if (str < end)
2172 				*str = '%';
2173 			++str;
2174 			break;
2175 
2176 		default: {
2177 			unsigned long long num;
2178 
2179 			switch (spec.type) {
2180 
2181 			case FORMAT_TYPE_LONG_LONG:
2182 				num = get_arg(long long);
2183 				break;
2184 			case FORMAT_TYPE_ULONG:
2185 			case FORMAT_TYPE_LONG:
2186 				num = get_arg(unsigned long);
2187 				break;
2188 			case FORMAT_TYPE_SIZE_T:
2189 				num = get_arg(size_t);
2190 				break;
2191 			case FORMAT_TYPE_PTRDIFF:
2192 				num = get_arg(ptrdiff_t);
2193 				break;
2194 			case FORMAT_TYPE_UBYTE:
2195 				num = get_arg(unsigned char);
2196 				break;
2197 			case FORMAT_TYPE_BYTE:
2198 				num = get_arg(signed char);
2199 				break;
2200 			case FORMAT_TYPE_USHORT:
2201 				num = get_arg(unsigned short);
2202 				break;
2203 			case FORMAT_TYPE_SHORT:
2204 				num = get_arg(short);
2205 				break;
2206 			case FORMAT_TYPE_UINT:
2207 				num = get_arg(unsigned int);
2208 				break;
2209 			default:
2210 				num = get_arg(int);
2211 			}
2212 
2213 			str = number(str, end, num, spec);
2214 		} /* default: */
2215 		} /* switch(spec.type) */
2216 	} /* while(*fmt) */
2217 
2218 	if (size > 0) {
2219 		if (str < end)
2220 			*str = '\0';
2221 		else
2222 			end[-1] = '\0';
2223 	}
2224 
2225 #undef get_arg
2226 
2227 	/* the trailing null byte doesn't count towards the total */
2228 	return str - buf;
2229 }
2230 EXPORT_SYMBOL_GPL(bstr_printf);
2231 
2232 /**
2233  * bprintf - Parse a format string and place args' binary value in a buffer
2234  * @bin_buf: The buffer to place args' binary value
2235  * @size: The size of the buffer(by words(32bits), not characters)
2236  * @fmt: The format string to use
2237  * @...: Arguments for the format string
2238  *
2239  * The function returns the number of words(u32) written
2240  * into @bin_buf.
2241  */
2242 int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...)
2243 {
2244 	va_list args;
2245 	int ret;
2246 
2247 	va_start(args, fmt);
2248 	ret = vbin_printf(bin_buf, size, fmt, args);
2249 	va_end(args);
2250 
2251 	return ret;
2252 }
2253 EXPORT_SYMBOL_GPL(bprintf);
2254 
2255 #endif /* CONFIG_BINARY_PRINTF */
2256 
2257 /**
2258  * vsscanf - Unformat a buffer into a list of arguments
2259  * @buf:	input buffer
2260  * @fmt:	format of buffer
2261  * @args:	arguments
2262  */
2263 int vsscanf(const char *buf, const char *fmt, va_list args)
2264 {
2265 	const char *str = buf;
2266 	char *next;
2267 	char digit;
2268 	int num = 0;
2269 	u8 qualifier;
2270 	unsigned int base;
2271 	union {
2272 		long long s;
2273 		unsigned long long u;
2274 	} val;
2275 	s16 field_width;
2276 	bool is_sign;
2277 
2278 	while (*fmt) {
2279 		/* skip any white space in format */
2280 		/* white space in format matchs any amount of
2281 		 * white space, including none, in the input.
2282 		 */
2283 		if (isspace(*fmt)) {
2284 			fmt = skip_spaces(++fmt);
2285 			str = skip_spaces(str);
2286 		}
2287 
2288 		/* anything that is not a conversion must match exactly */
2289 		if (*fmt != '%' && *fmt) {
2290 			if (*fmt++ != *str++)
2291 				break;
2292 			continue;
2293 		}
2294 
2295 		if (!*fmt)
2296 			break;
2297 		++fmt;
2298 
2299 		/* skip this conversion.
2300 		 * advance both strings to next white space
2301 		 */
2302 		if (*fmt == '*') {
2303 			if (!*str)
2304 				break;
2305 			while (!isspace(*fmt) && *fmt != '%' && *fmt)
2306 				fmt++;
2307 			while (!isspace(*str) && *str)
2308 				str++;
2309 			continue;
2310 		}
2311 
2312 		/* get field width */
2313 		field_width = -1;
2314 		if (isdigit(*fmt)) {
2315 			field_width = skip_atoi(&fmt);
2316 			if (field_width <= 0)
2317 				break;
2318 		}
2319 
2320 		/* get conversion qualifier */
2321 		qualifier = -1;
2322 		if (*fmt == 'h' || _tolower(*fmt) == 'l' ||
2323 		    _tolower(*fmt) == 'z') {
2324 			qualifier = *fmt++;
2325 			if (unlikely(qualifier == *fmt)) {
2326 				if (qualifier == 'h') {
2327 					qualifier = 'H';
2328 					fmt++;
2329 				} else if (qualifier == 'l') {
2330 					qualifier = 'L';
2331 					fmt++;
2332 				}
2333 			}
2334 		}
2335 
2336 		if (!*fmt)
2337 			break;
2338 
2339 		if (*fmt == 'n') {
2340 			/* return number of characters read so far */
2341 			*va_arg(args, int *) = str - buf;
2342 			++fmt;
2343 			continue;
2344 		}
2345 
2346 		if (!*str)
2347 			break;
2348 
2349 		base = 10;
2350 		is_sign = 0;
2351 
2352 		switch (*fmt++) {
2353 		case 'c':
2354 		{
2355 			char *s = (char *)va_arg(args, char*);
2356 			if (field_width == -1)
2357 				field_width = 1;
2358 			do {
2359 				*s++ = *str++;
2360 			} while (--field_width > 0 && *str);
2361 			num++;
2362 		}
2363 		continue;
2364 		case 's':
2365 		{
2366 			char *s = (char *)va_arg(args, char *);
2367 			if (field_width == -1)
2368 				field_width = SHRT_MAX;
2369 			/* first, skip leading white space in buffer */
2370 			str = skip_spaces(str);
2371 
2372 			/* now copy until next white space */
2373 			while (*str && !isspace(*str) && field_width--)
2374 				*s++ = *str++;
2375 			*s = '\0';
2376 			num++;
2377 		}
2378 		continue;
2379 		case 'o':
2380 			base = 8;
2381 			break;
2382 		case 'x':
2383 		case 'X':
2384 			base = 16;
2385 			break;
2386 		case 'i':
2387 			base = 0;
2388 		case 'd':
2389 			is_sign = 1;
2390 		case 'u':
2391 			break;
2392 		case '%':
2393 			/* looking for '%' in str */
2394 			if (*str++ != '%')
2395 				return num;
2396 			continue;
2397 		default:
2398 			/* invalid format; stop here */
2399 			return num;
2400 		}
2401 
2402 		/* have some sort of integer conversion.
2403 		 * first, skip white space in buffer.
2404 		 */
2405 		str = skip_spaces(str);
2406 
2407 		digit = *str;
2408 		if (is_sign && digit == '-')
2409 			digit = *(str + 1);
2410 
2411 		if (!digit
2412 		    || (base == 16 && !isxdigit(digit))
2413 		    || (base == 10 && !isdigit(digit))
2414 		    || (base == 8 && (!isdigit(digit) || digit > '7'))
2415 		    || (base == 0 && !isdigit(digit)))
2416 			break;
2417 
2418 		if (is_sign)
2419 			val.s = qualifier != 'L' ?
2420 				simple_strtol(str, &next, base) :
2421 				simple_strtoll(str, &next, base);
2422 		else
2423 			val.u = qualifier != 'L' ?
2424 				simple_strtoul(str, &next, base) :
2425 				simple_strtoull(str, &next, base);
2426 
2427 		if (field_width > 0 && next - str > field_width) {
2428 			if (base == 0)
2429 				_parse_integer_fixup_radix(str, &base);
2430 			while (next - str > field_width) {
2431 				if (is_sign)
2432 					val.s = div_s64(val.s, base);
2433 				else
2434 					val.u = div_u64(val.u, base);
2435 				--next;
2436 			}
2437 		}
2438 
2439 		switch (qualifier) {
2440 		case 'H':	/* that's 'hh' in format */
2441 			if (is_sign)
2442 				*va_arg(args, signed char *) = val.s;
2443 			else
2444 				*va_arg(args, unsigned char *) = val.u;
2445 			break;
2446 		case 'h':
2447 			if (is_sign)
2448 				*va_arg(args, short *) = val.s;
2449 			else
2450 				*va_arg(args, unsigned short *) = val.u;
2451 			break;
2452 		case 'l':
2453 			if (is_sign)
2454 				*va_arg(args, long *) = val.s;
2455 			else
2456 				*va_arg(args, unsigned long *) = val.u;
2457 			break;
2458 		case 'L':
2459 			if (is_sign)
2460 				*va_arg(args, long long *) = val.s;
2461 			else
2462 				*va_arg(args, unsigned long long *) = val.u;
2463 			break;
2464 		case 'Z':
2465 		case 'z':
2466 			*va_arg(args, size_t *) = val.u;
2467 			break;
2468 		default:
2469 			if (is_sign)
2470 				*va_arg(args, int *) = val.s;
2471 			else
2472 				*va_arg(args, unsigned int *) = val.u;
2473 			break;
2474 		}
2475 		num++;
2476 
2477 		if (!next)
2478 			break;
2479 		str = next;
2480 	}
2481 
2482 	return num;
2483 }
2484 EXPORT_SYMBOL(vsscanf);
2485 
2486 /**
2487  * sscanf - Unformat a buffer into a list of arguments
2488  * @buf:	input buffer
2489  * @fmt:	formatting of buffer
2490  * @...:	resulting arguments
2491  */
2492 int sscanf(const char *buf, const char *fmt, ...)
2493 {
2494 	va_list args;
2495 	int i;
2496 
2497 	va_start(args, fmt);
2498 	i = vsscanf(buf, fmt, args);
2499 	va_end(args);
2500 
2501 	return i;
2502 }
2503 EXPORT_SYMBOL(sscanf);
2504