xref: /openbmc/linux/lib/vsprintf.c (revision 9d749629)
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 <net/addrconf.h>
30 
31 #include <asm/page.h>		/* for PAGE_SIZE */
32 #include <asm/sections.h>	/* for dereference_function_descriptor() */
33 
34 #include "kstrtox.h"
35 
36 /**
37  * simple_strtoull - convert a string to an unsigned long long
38  * @cp: The start of the string
39  * @endp: A pointer to the end of the parsed string will be placed here
40  * @base: The number base to use
41  *
42  * This function is obsolete. Please use kstrtoull instead.
43  */
44 unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base)
45 {
46 	unsigned long long result;
47 	unsigned int rv;
48 
49 	cp = _parse_integer_fixup_radix(cp, &base);
50 	rv = _parse_integer(cp, base, &result);
51 	/* FIXME */
52 	cp += (rv & ~KSTRTOX_OVERFLOW);
53 
54 	if (endp)
55 		*endp = (char *)cp;
56 
57 	return result;
58 }
59 EXPORT_SYMBOL(simple_strtoull);
60 
61 /**
62  * simple_strtoul - convert a string to an unsigned long
63  * @cp: The start of the string
64  * @endp: A pointer to the end of the parsed string will be placed here
65  * @base: The number base to use
66  *
67  * This function is obsolete. Please use kstrtoul instead.
68  */
69 unsigned long simple_strtoul(const char *cp, char **endp, unsigned int base)
70 {
71 	return simple_strtoull(cp, endp, base);
72 }
73 EXPORT_SYMBOL(simple_strtoul);
74 
75 /**
76  * simple_strtol - convert a string to a signed long
77  * @cp: The start of the string
78  * @endp: A pointer to the end of the parsed string will be placed here
79  * @base: The number base to use
80  *
81  * This function is obsolete. Please use kstrtol instead.
82  */
83 long simple_strtol(const char *cp, char **endp, unsigned int base)
84 {
85 	if (*cp == '-')
86 		return -simple_strtoul(cp + 1, endp, base);
87 
88 	return simple_strtoul(cp, endp, base);
89 }
90 EXPORT_SYMBOL(simple_strtol);
91 
92 /**
93  * simple_strtoll - convert a string to a signed long long
94  * @cp: The start of the string
95  * @endp: A pointer to the end of the parsed string will be placed here
96  * @base: The number base to use
97  *
98  * This function is obsolete. Please use kstrtoll instead.
99  */
100 long long simple_strtoll(const char *cp, char **endp, unsigned int base)
101 {
102 	if (*cp == '-')
103 		return -simple_strtoull(cp + 1, endp, base);
104 
105 	return simple_strtoull(cp, endp, base);
106 }
107 EXPORT_SYMBOL(simple_strtoll);
108 
109 static noinline_for_stack
110 int skip_atoi(const char **s)
111 {
112 	int i = 0;
113 
114 	while (isdigit(**s))
115 		i = i*10 + *((*s)++) - '0';
116 
117 	return i;
118 }
119 
120 /* Decimal conversion is by far the most typical, and is used
121  * for /proc and /sys data. This directly impacts e.g. top performance
122  * with many processes running. We optimize it for speed
123  * using ideas described at <http://www.cs.uiowa.edu/~jones/bcd/divide.html>
124  * (with permission from the author, Douglas W. Jones).
125  */
126 
127 #if BITS_PER_LONG != 32 || BITS_PER_LONG_LONG != 64
128 /* Formats correctly any integer in [0, 999999999] */
129 static noinline_for_stack
130 char *put_dec_full9(char *buf, unsigned q)
131 {
132 	unsigned r;
133 
134 	/*
135 	 * Possible ways to approx. divide by 10
136 	 * (x * 0x1999999a) >> 32 x < 1073741829 (multiply must be 64-bit)
137 	 * (x * 0xcccd) >> 19     x <      81920 (x < 262149 when 64-bit mul)
138 	 * (x * 0x6667) >> 18     x <      43699
139 	 * (x * 0x3334) >> 17     x <      16389
140 	 * (x * 0x199a) >> 16     x <      16389
141 	 * (x * 0x0ccd) >> 15     x <      16389
142 	 * (x * 0x0667) >> 14     x <       2739
143 	 * (x * 0x0334) >> 13     x <       1029
144 	 * (x * 0x019a) >> 12     x <       1029
145 	 * (x * 0x00cd) >> 11     x <       1029 shorter code than * 0x67 (on i386)
146 	 * (x * 0x0067) >> 10     x <        179
147 	 * (x * 0x0034) >>  9     x <         69 same
148 	 * (x * 0x001a) >>  8     x <         69 same
149 	 * (x * 0x000d) >>  7     x <         69 same, shortest code (on i386)
150 	 * (x * 0x0007) >>  6     x <         19
151 	 * See <http://www.cs.uiowa.edu/~jones/bcd/divide.html>
152 	 */
153 	r      = (q * (uint64_t)0x1999999a) >> 32;
154 	*buf++ = (q - 10 * r) + '0'; /* 1 */
155 	q      = (r * (uint64_t)0x1999999a) >> 32;
156 	*buf++ = (r - 10 * q) + '0'; /* 2 */
157 	r      = (q * (uint64_t)0x1999999a) >> 32;
158 	*buf++ = (q - 10 * r) + '0'; /* 3 */
159 	q      = (r * (uint64_t)0x1999999a) >> 32;
160 	*buf++ = (r - 10 * q) + '0'; /* 4 */
161 	r      = (q * (uint64_t)0x1999999a) >> 32;
162 	*buf++ = (q - 10 * r) + '0'; /* 5 */
163 	/* Now value is under 10000, can avoid 64-bit multiply */
164 	q      = (r * 0x199a) >> 16;
165 	*buf++ = (r - 10 * q)  + '0'; /* 6 */
166 	r      = (q * 0xcd) >> 11;
167 	*buf++ = (q - 10 * r)  + '0'; /* 7 */
168 	q      = (r * 0xcd) >> 11;
169 	*buf++ = (r - 10 * q) + '0'; /* 8 */
170 	*buf++ = q + '0'; /* 9 */
171 	return buf;
172 }
173 #endif
174 
175 /* Similar to above but do not pad with zeros.
176  * Code can be easily arranged to print 9 digits too, but our callers
177  * always call put_dec_full9() instead when the number has 9 decimal digits.
178  */
179 static noinline_for_stack
180 char *put_dec_trunc8(char *buf, unsigned r)
181 {
182 	unsigned q;
183 
184 	/* Copy of previous function's body with added early returns */
185 	while (r >= 10000) {
186 		q = r + '0';
187 		r  = (r * (uint64_t)0x1999999a) >> 32;
188 		*buf++ = q - 10*r;
189 	}
190 
191 	q      = (r * 0x199a) >> 16;	/* r <= 9999 */
192 	*buf++ = (r - 10 * q)  + '0';
193 	if (q == 0)
194 		return buf;
195 	r      = (q * 0xcd) >> 11;	/* q <= 999 */
196 	*buf++ = (q - 10 * r)  + '0';
197 	if (r == 0)
198 		return buf;
199 	q      = (r * 0xcd) >> 11;	/* r <= 99 */
200 	*buf++ = (r - 10 * q) + '0';
201 	if (q == 0)
202 		return buf;
203 	*buf++ = q + '0';		 /* q <= 9 */
204 	return buf;
205 }
206 
207 /* There are two algorithms to print larger numbers.
208  * One is generic: divide by 1000000000 and repeatedly print
209  * groups of (up to) 9 digits. It's conceptually simple,
210  * but requires a (unsigned long long) / 1000000000 division.
211  *
212  * Second algorithm splits 64-bit unsigned long long into 16-bit chunks,
213  * manipulates them cleverly and generates groups of 4 decimal digits.
214  * It so happens that it does NOT require long long division.
215  *
216  * If long is > 32 bits, division of 64-bit values is relatively easy,
217  * and we will use the first algorithm.
218  * If long long is > 64 bits (strange architecture with VERY large long long),
219  * second algorithm can't be used, and we again use the first one.
220  *
221  * Else (if long is 32 bits and long long is 64 bits) we use second one.
222  */
223 
224 #if BITS_PER_LONG != 32 || BITS_PER_LONG_LONG != 64
225 
226 /* First algorithm: generic */
227 
228 static
229 char *put_dec(char *buf, unsigned long long n)
230 {
231 	if (n >= 100*1000*1000) {
232 		while (n >= 1000*1000*1000)
233 			buf = put_dec_full9(buf, do_div(n, 1000*1000*1000));
234 		if (n >= 100*1000*1000)
235 			return put_dec_full9(buf, n);
236 	}
237 	return put_dec_trunc8(buf, n);
238 }
239 
240 #else
241 
242 /* Second algorithm: valid only for 64-bit long longs */
243 
244 /* See comment in put_dec_full9 for choice of constants */
245 static noinline_for_stack
246 void put_dec_full4(char *buf, unsigned q)
247 {
248 	unsigned r;
249 	r      = (q * 0xccd) >> 15;
250 	buf[0] = (q - 10 * r) + '0';
251 	q      = (r * 0xcd) >> 11;
252 	buf[1] = (r - 10 * q)  + '0';
253 	r      = (q * 0xcd) >> 11;
254 	buf[2] = (q - 10 * r)  + '0';
255 	buf[3] = r + '0';
256 }
257 
258 /*
259  * Call put_dec_full4 on x % 10000, return x / 10000.
260  * The approximation x/10000 == (x * 0x346DC5D7) >> 43
261  * holds for all x < 1,128,869,999.  The largest value this
262  * helper will ever be asked to convert is 1,125,520,955.
263  * (d1 in the put_dec code, assuming n is all-ones).
264  */
265 static
266 unsigned put_dec_helper4(char *buf, unsigned x)
267 {
268         uint32_t q = (x * (uint64_t)0x346DC5D7) >> 43;
269 
270         put_dec_full4(buf, x - q * 10000);
271         return q;
272 }
273 
274 /* Based on code by Douglas W. Jones found at
275  * <http://www.cs.uiowa.edu/~jones/bcd/decimal.html#sixtyfour>
276  * (with permission from the author).
277  * Performs no 64-bit division and hence should be fast on 32-bit machines.
278  */
279 static
280 char *put_dec(char *buf, unsigned long long n)
281 {
282 	uint32_t d3, d2, d1, q, h;
283 
284 	if (n < 100*1000*1000)
285 		return put_dec_trunc8(buf, n);
286 
287 	d1  = ((uint32_t)n >> 16); /* implicit "& 0xffff" */
288 	h   = (n >> 32);
289 	d2  = (h      ) & 0xffff;
290 	d3  = (h >> 16); /* implicit "& 0xffff" */
291 
292 	q   = 656 * d3 + 7296 * d2 + 5536 * d1 + ((uint32_t)n & 0xffff);
293 	q = put_dec_helper4(buf, q);
294 
295 	q += 7671 * d3 + 9496 * d2 + 6 * d1;
296 	q = put_dec_helper4(buf+4, q);
297 
298 	q += 4749 * d3 + 42 * d2;
299 	q = put_dec_helper4(buf+8, q);
300 
301 	q += 281 * d3;
302 	buf += 12;
303 	if (q)
304 		buf = put_dec_trunc8(buf, q);
305 	else while (buf[-1] == '0')
306 		--buf;
307 
308 	return buf;
309 }
310 
311 #endif
312 
313 /*
314  * Convert passed number to decimal string.
315  * Returns the length of string.  On buffer overflow, returns 0.
316  *
317  * If speed is not important, use snprintf(). It's easy to read the code.
318  */
319 int num_to_str(char *buf, int size, unsigned long long num)
320 {
321 	char tmp[sizeof(num) * 3];
322 	int idx, len;
323 
324 	/* put_dec() may work incorrectly for num = 0 (generate "", not "0") */
325 	if (num <= 9) {
326 		tmp[0] = '0' + num;
327 		len = 1;
328 	} else {
329 		len = put_dec(tmp, num) - tmp;
330 	}
331 
332 	if (len > size)
333 		return 0;
334 	for (idx = 0; idx < len; ++idx)
335 		buf[idx] = tmp[len - idx - 1];
336 	return len;
337 }
338 
339 #define ZEROPAD	1		/* pad with zero */
340 #define SIGN	2		/* unsigned/signed long */
341 #define PLUS	4		/* show plus */
342 #define SPACE	8		/* space if plus */
343 #define LEFT	16		/* left justified */
344 #define SMALL	32		/* use lowercase in hex (must be 32 == 0x20) */
345 #define SPECIAL	64		/* prefix hex with "0x", octal with "0" */
346 
347 enum format_type {
348 	FORMAT_TYPE_NONE, /* Just a string part */
349 	FORMAT_TYPE_WIDTH,
350 	FORMAT_TYPE_PRECISION,
351 	FORMAT_TYPE_CHAR,
352 	FORMAT_TYPE_STR,
353 	FORMAT_TYPE_PTR,
354 	FORMAT_TYPE_PERCENT_CHAR,
355 	FORMAT_TYPE_INVALID,
356 	FORMAT_TYPE_LONG_LONG,
357 	FORMAT_TYPE_ULONG,
358 	FORMAT_TYPE_LONG,
359 	FORMAT_TYPE_UBYTE,
360 	FORMAT_TYPE_BYTE,
361 	FORMAT_TYPE_USHORT,
362 	FORMAT_TYPE_SHORT,
363 	FORMAT_TYPE_UINT,
364 	FORMAT_TYPE_INT,
365 	FORMAT_TYPE_NRCHARS,
366 	FORMAT_TYPE_SIZE_T,
367 	FORMAT_TYPE_PTRDIFF
368 };
369 
370 struct printf_spec {
371 	u8	type;		/* format_type enum */
372 	u8	flags;		/* flags to number() */
373 	u8	base;		/* number base, 8, 10 or 16 only */
374 	u8	qualifier;	/* number qualifier, one of 'hHlLtzZ' */
375 	s16	field_width;	/* width of output field */
376 	s16	precision;	/* # of digits/chars */
377 };
378 
379 static noinline_for_stack
380 char *number(char *buf, char *end, unsigned long long num,
381 	     struct printf_spec spec)
382 {
383 	/* we are called with base 8, 10 or 16, only, thus don't need "G..."  */
384 	static const char digits[16] = "0123456789ABCDEF"; /* "GHIJKLMNOPQRSTUVWXYZ"; */
385 
386 	char tmp[66];
387 	char sign;
388 	char locase;
389 	int need_pfx = ((spec.flags & SPECIAL) && spec.base != 10);
390 	int i;
391 	bool is_zero = num == 0LL;
392 
393 	/* locase = 0 or 0x20. ORing digits or letters with 'locase'
394 	 * produces same digits or (maybe lowercased) letters */
395 	locase = (spec.flags & SMALL);
396 	if (spec.flags & LEFT)
397 		spec.flags &= ~ZEROPAD;
398 	sign = 0;
399 	if (spec.flags & SIGN) {
400 		if ((signed long long)num < 0) {
401 			sign = '-';
402 			num = -(signed long long)num;
403 			spec.field_width--;
404 		} else if (spec.flags & PLUS) {
405 			sign = '+';
406 			spec.field_width--;
407 		} else if (spec.flags & SPACE) {
408 			sign = ' ';
409 			spec.field_width--;
410 		}
411 	}
412 	if (need_pfx) {
413 		if (spec.base == 16)
414 			spec.field_width -= 2;
415 		else if (!is_zero)
416 			spec.field_width--;
417 	}
418 
419 	/* generate full string in tmp[], in reverse order */
420 	i = 0;
421 	if (num < spec.base)
422 		tmp[i++] = digits[num] | locase;
423 	/* Generic code, for any base:
424 	else do {
425 		tmp[i++] = (digits[do_div(num,base)] | locase);
426 	} while (num != 0);
427 	*/
428 	else if (spec.base != 10) { /* 8 or 16 */
429 		int mask = spec.base - 1;
430 		int shift = 3;
431 
432 		if (spec.base == 16)
433 			shift = 4;
434 		do {
435 			tmp[i++] = (digits[((unsigned char)num) & mask] | locase);
436 			num >>= shift;
437 		} while (num);
438 	} else { /* base 10 */
439 		i = put_dec(tmp, num) - tmp;
440 	}
441 
442 	/* printing 100 using %2d gives "100", not "00" */
443 	if (i > spec.precision)
444 		spec.precision = i;
445 	/* leading space padding */
446 	spec.field_width -= spec.precision;
447 	if (!(spec.flags & (ZEROPAD+LEFT))) {
448 		while (--spec.field_width >= 0) {
449 			if (buf < end)
450 				*buf = ' ';
451 			++buf;
452 		}
453 	}
454 	/* sign */
455 	if (sign) {
456 		if (buf < end)
457 			*buf = sign;
458 		++buf;
459 	}
460 	/* "0x" / "0" prefix */
461 	if (need_pfx) {
462 		if (spec.base == 16 || !is_zero) {
463 			if (buf < end)
464 				*buf = '0';
465 			++buf;
466 		}
467 		if (spec.base == 16) {
468 			if (buf < end)
469 				*buf = ('X' | locase);
470 			++buf;
471 		}
472 	}
473 	/* zero or space padding */
474 	if (!(spec.flags & LEFT)) {
475 		char c = (spec.flags & ZEROPAD) ? '0' : ' ';
476 		while (--spec.field_width >= 0) {
477 			if (buf < end)
478 				*buf = c;
479 			++buf;
480 		}
481 	}
482 	/* hmm even more zero padding? */
483 	while (i <= --spec.precision) {
484 		if (buf < end)
485 			*buf = '0';
486 		++buf;
487 	}
488 	/* actual digits of result */
489 	while (--i >= 0) {
490 		if (buf < end)
491 			*buf = tmp[i];
492 		++buf;
493 	}
494 	/* trailing space padding */
495 	while (--spec.field_width >= 0) {
496 		if (buf < end)
497 			*buf = ' ';
498 		++buf;
499 	}
500 
501 	return buf;
502 }
503 
504 static noinline_for_stack
505 char *string(char *buf, char *end, const char *s, struct printf_spec spec)
506 {
507 	int len, i;
508 
509 	if ((unsigned long)s < PAGE_SIZE)
510 		s = "(null)";
511 
512 	len = strnlen(s, spec.precision);
513 
514 	if (!(spec.flags & LEFT)) {
515 		while (len < spec.field_width--) {
516 			if (buf < end)
517 				*buf = ' ';
518 			++buf;
519 		}
520 	}
521 	for (i = 0; i < len; ++i) {
522 		if (buf < end)
523 			*buf = *s;
524 		++buf; ++s;
525 	}
526 	while (len < spec.field_width--) {
527 		if (buf < end)
528 			*buf = ' ';
529 		++buf;
530 	}
531 
532 	return buf;
533 }
534 
535 static noinline_for_stack
536 char *symbol_string(char *buf, char *end, void *ptr,
537 		    struct printf_spec spec, char ext)
538 {
539 	unsigned long value = (unsigned long) ptr;
540 #ifdef CONFIG_KALLSYMS
541 	char sym[KSYM_SYMBOL_LEN];
542 	if (ext == 'B')
543 		sprint_backtrace(sym, value);
544 	else if (ext != 'f' && ext != 's')
545 		sprint_symbol(sym, value);
546 	else
547 		sprint_symbol_no_offset(sym, value);
548 
549 	return string(buf, end, sym, spec);
550 #else
551 	spec.field_width = 2 * sizeof(void *);
552 	spec.flags |= SPECIAL | SMALL | ZEROPAD;
553 	spec.base = 16;
554 
555 	return number(buf, end, value, spec);
556 #endif
557 }
558 
559 static noinline_for_stack
560 char *resource_string(char *buf, char *end, struct resource *res,
561 		      struct printf_spec spec, const char *fmt)
562 {
563 #ifndef IO_RSRC_PRINTK_SIZE
564 #define IO_RSRC_PRINTK_SIZE	6
565 #endif
566 
567 #ifndef MEM_RSRC_PRINTK_SIZE
568 #define MEM_RSRC_PRINTK_SIZE	10
569 #endif
570 	static const struct printf_spec io_spec = {
571 		.base = 16,
572 		.field_width = IO_RSRC_PRINTK_SIZE,
573 		.precision = -1,
574 		.flags = SPECIAL | SMALL | ZEROPAD,
575 	};
576 	static const struct printf_spec mem_spec = {
577 		.base = 16,
578 		.field_width = MEM_RSRC_PRINTK_SIZE,
579 		.precision = -1,
580 		.flags = SPECIAL | SMALL | ZEROPAD,
581 	};
582 	static const struct printf_spec bus_spec = {
583 		.base = 16,
584 		.field_width = 2,
585 		.precision = -1,
586 		.flags = SMALL | ZEROPAD,
587 	};
588 	static const struct printf_spec dec_spec = {
589 		.base = 10,
590 		.precision = -1,
591 		.flags = 0,
592 	};
593 	static const struct printf_spec str_spec = {
594 		.field_width = -1,
595 		.precision = 10,
596 		.flags = LEFT,
597 	};
598 	static const struct printf_spec flag_spec = {
599 		.base = 16,
600 		.precision = -1,
601 		.flags = SPECIAL | SMALL,
602 	};
603 
604 	/* 32-bit res (sizeof==4): 10 chars in dec, 10 in hex ("0x" + 8)
605 	 * 64-bit res (sizeof==8): 20 chars in dec, 18 in hex ("0x" + 16) */
606 #define RSRC_BUF_SIZE		((2 * sizeof(resource_size_t)) + 4)
607 #define FLAG_BUF_SIZE		(2 * sizeof(res->flags))
608 #define DECODED_BUF_SIZE	sizeof("[mem - 64bit pref window disabled]")
609 #define RAW_BUF_SIZE		sizeof("[mem - flags 0x]")
610 	char sym[max(2*RSRC_BUF_SIZE + DECODED_BUF_SIZE,
611 		     2*RSRC_BUF_SIZE + FLAG_BUF_SIZE + RAW_BUF_SIZE)];
612 
613 	char *p = sym, *pend = sym + sizeof(sym);
614 	int decode = (fmt[0] == 'R') ? 1 : 0;
615 	const struct printf_spec *specp;
616 
617 	*p++ = '[';
618 	if (res->flags & IORESOURCE_IO) {
619 		p = string(p, pend, "io  ", str_spec);
620 		specp = &io_spec;
621 	} else if (res->flags & IORESOURCE_MEM) {
622 		p = string(p, pend, "mem ", str_spec);
623 		specp = &mem_spec;
624 	} else if (res->flags & IORESOURCE_IRQ) {
625 		p = string(p, pend, "irq ", str_spec);
626 		specp = &dec_spec;
627 	} else if (res->flags & IORESOURCE_DMA) {
628 		p = string(p, pend, "dma ", str_spec);
629 		specp = &dec_spec;
630 	} else if (res->flags & IORESOURCE_BUS) {
631 		p = string(p, pend, "bus ", str_spec);
632 		specp = &bus_spec;
633 	} else {
634 		p = string(p, pend, "??? ", str_spec);
635 		specp = &mem_spec;
636 		decode = 0;
637 	}
638 	p = number(p, pend, res->start, *specp);
639 	if (res->start != res->end) {
640 		*p++ = '-';
641 		p = number(p, pend, res->end, *specp);
642 	}
643 	if (decode) {
644 		if (res->flags & IORESOURCE_MEM_64)
645 			p = string(p, pend, " 64bit", str_spec);
646 		if (res->flags & IORESOURCE_PREFETCH)
647 			p = string(p, pend, " pref", str_spec);
648 		if (res->flags & IORESOURCE_WINDOW)
649 			p = string(p, pend, " window", str_spec);
650 		if (res->flags & IORESOURCE_DISABLED)
651 			p = string(p, pend, " disabled", str_spec);
652 	} else {
653 		p = string(p, pend, " flags ", str_spec);
654 		p = number(p, pend, res->flags, flag_spec);
655 	}
656 	*p++ = ']';
657 	*p = '\0';
658 
659 	return string(buf, end, sym, spec);
660 }
661 
662 static noinline_for_stack
663 char *hex_string(char *buf, char *end, u8 *addr, struct printf_spec spec,
664 		 const char *fmt)
665 {
666 	int i, len = 1;		/* if we pass '%ph[CDN]', field witdh remains
667 				   negative value, fallback to the default */
668 	char separator;
669 
670 	if (spec.field_width == 0)
671 		/* nothing to print */
672 		return buf;
673 
674 	if (ZERO_OR_NULL_PTR(addr))
675 		/* NULL pointer */
676 		return string(buf, end, NULL, spec);
677 
678 	switch (fmt[1]) {
679 	case 'C':
680 		separator = ':';
681 		break;
682 	case 'D':
683 		separator = '-';
684 		break;
685 	case 'N':
686 		separator = 0;
687 		break;
688 	default:
689 		separator = ' ';
690 		break;
691 	}
692 
693 	if (spec.field_width > 0)
694 		len = min_t(int, spec.field_width, 64);
695 
696 	for (i = 0; i < len && buf < end - 1; i++) {
697 		buf = hex_byte_pack(buf, addr[i]);
698 
699 		if (buf < end && separator && i != len - 1)
700 			*buf++ = separator;
701 	}
702 
703 	return buf;
704 }
705 
706 static noinline_for_stack
707 char *mac_address_string(char *buf, char *end, u8 *addr,
708 			 struct printf_spec spec, const char *fmt)
709 {
710 	char mac_addr[sizeof("xx:xx:xx:xx:xx:xx")];
711 	char *p = mac_addr;
712 	int i;
713 	char separator;
714 	bool reversed = false;
715 
716 	switch (fmt[1]) {
717 	case 'F':
718 		separator = '-';
719 		break;
720 
721 	case 'R':
722 		reversed = true;
723 		/* fall through */
724 
725 	default:
726 		separator = ':';
727 		break;
728 	}
729 
730 	for (i = 0; i < 6; i++) {
731 		if (reversed)
732 			p = hex_byte_pack(p, addr[5 - i]);
733 		else
734 			p = hex_byte_pack(p, addr[i]);
735 
736 		if (fmt[0] == 'M' && i != 5)
737 			*p++ = separator;
738 	}
739 	*p = '\0';
740 
741 	return string(buf, end, mac_addr, spec);
742 }
743 
744 static noinline_for_stack
745 char *ip4_string(char *p, const u8 *addr, const char *fmt)
746 {
747 	int i;
748 	bool leading_zeros = (fmt[0] == 'i');
749 	int index;
750 	int step;
751 
752 	switch (fmt[2]) {
753 	case 'h':
754 #ifdef __BIG_ENDIAN
755 		index = 0;
756 		step = 1;
757 #else
758 		index = 3;
759 		step = -1;
760 #endif
761 		break;
762 	case 'l':
763 		index = 3;
764 		step = -1;
765 		break;
766 	case 'n':
767 	case 'b':
768 	default:
769 		index = 0;
770 		step = 1;
771 		break;
772 	}
773 	for (i = 0; i < 4; i++) {
774 		char temp[3];	/* hold each IP quad in reverse order */
775 		int digits = put_dec_trunc8(temp, addr[index]) - temp;
776 		if (leading_zeros) {
777 			if (digits < 3)
778 				*p++ = '0';
779 			if (digits < 2)
780 				*p++ = '0';
781 		}
782 		/* reverse the digits in the quad */
783 		while (digits--)
784 			*p++ = temp[digits];
785 		if (i < 3)
786 			*p++ = '.';
787 		index += step;
788 	}
789 	*p = '\0';
790 
791 	return p;
792 }
793 
794 static noinline_for_stack
795 char *ip6_compressed_string(char *p, const char *addr)
796 {
797 	int i, j, range;
798 	unsigned char zerolength[8];
799 	int longest = 1;
800 	int colonpos = -1;
801 	u16 word;
802 	u8 hi, lo;
803 	bool needcolon = false;
804 	bool useIPv4;
805 	struct in6_addr in6;
806 
807 	memcpy(&in6, addr, sizeof(struct in6_addr));
808 
809 	useIPv4 = ipv6_addr_v4mapped(&in6) || ipv6_addr_is_isatap(&in6);
810 
811 	memset(zerolength, 0, sizeof(zerolength));
812 
813 	if (useIPv4)
814 		range = 6;
815 	else
816 		range = 8;
817 
818 	/* find position of longest 0 run */
819 	for (i = 0; i < range; i++) {
820 		for (j = i; j < range; j++) {
821 			if (in6.s6_addr16[j] != 0)
822 				break;
823 			zerolength[i]++;
824 		}
825 	}
826 	for (i = 0; i < range; i++) {
827 		if (zerolength[i] > longest) {
828 			longest = zerolength[i];
829 			colonpos = i;
830 		}
831 	}
832 	if (longest == 1)		/* don't compress a single 0 */
833 		colonpos = -1;
834 
835 	/* emit address */
836 	for (i = 0; i < range; i++) {
837 		if (i == colonpos) {
838 			if (needcolon || i == 0)
839 				*p++ = ':';
840 			*p++ = ':';
841 			needcolon = false;
842 			i += longest - 1;
843 			continue;
844 		}
845 		if (needcolon) {
846 			*p++ = ':';
847 			needcolon = false;
848 		}
849 		/* hex u16 without leading 0s */
850 		word = ntohs(in6.s6_addr16[i]);
851 		hi = word >> 8;
852 		lo = word & 0xff;
853 		if (hi) {
854 			if (hi > 0x0f)
855 				p = hex_byte_pack(p, hi);
856 			else
857 				*p++ = hex_asc_lo(hi);
858 			p = hex_byte_pack(p, lo);
859 		}
860 		else if (lo > 0x0f)
861 			p = hex_byte_pack(p, lo);
862 		else
863 			*p++ = hex_asc_lo(lo);
864 		needcolon = true;
865 	}
866 
867 	if (useIPv4) {
868 		if (needcolon)
869 			*p++ = ':';
870 		p = ip4_string(p, &in6.s6_addr[12], "I4");
871 	}
872 	*p = '\0';
873 
874 	return p;
875 }
876 
877 static noinline_for_stack
878 char *ip6_string(char *p, const char *addr, const char *fmt)
879 {
880 	int i;
881 
882 	for (i = 0; i < 8; i++) {
883 		p = hex_byte_pack(p, *addr++);
884 		p = hex_byte_pack(p, *addr++);
885 		if (fmt[0] == 'I' && i != 7)
886 			*p++ = ':';
887 	}
888 	*p = '\0';
889 
890 	return p;
891 }
892 
893 static noinline_for_stack
894 char *ip6_addr_string(char *buf, char *end, const u8 *addr,
895 		      struct printf_spec spec, const char *fmt)
896 {
897 	char ip6_addr[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255")];
898 
899 	if (fmt[0] == 'I' && fmt[2] == 'c')
900 		ip6_compressed_string(ip6_addr, addr);
901 	else
902 		ip6_string(ip6_addr, addr, fmt);
903 
904 	return string(buf, end, ip6_addr, spec);
905 }
906 
907 static noinline_for_stack
908 char *ip4_addr_string(char *buf, char *end, const u8 *addr,
909 		      struct printf_spec spec, const char *fmt)
910 {
911 	char ip4_addr[sizeof("255.255.255.255")];
912 
913 	ip4_string(ip4_addr, addr, fmt);
914 
915 	return string(buf, end, ip4_addr, spec);
916 }
917 
918 static noinline_for_stack
919 char *uuid_string(char *buf, char *end, const u8 *addr,
920 		  struct printf_spec spec, const char *fmt)
921 {
922 	char uuid[sizeof("xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx")];
923 	char *p = uuid;
924 	int i;
925 	static const u8 be[16] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
926 	static const u8 le[16] = {3,2,1,0,5,4,7,6,8,9,10,11,12,13,14,15};
927 	const u8 *index = be;
928 	bool uc = false;
929 
930 	switch (*(++fmt)) {
931 	case 'L':
932 		uc = true;		/* fall-through */
933 	case 'l':
934 		index = le;
935 		break;
936 	case 'B':
937 		uc = true;
938 		break;
939 	}
940 
941 	for (i = 0; i < 16; i++) {
942 		p = hex_byte_pack(p, addr[index[i]]);
943 		switch (i) {
944 		case 3:
945 		case 5:
946 		case 7:
947 		case 9:
948 			*p++ = '-';
949 			break;
950 		}
951 	}
952 
953 	*p = 0;
954 
955 	if (uc) {
956 		p = uuid;
957 		do {
958 			*p = toupper(*p);
959 		} while (*(++p));
960 	}
961 
962 	return string(buf, end, uuid, spec);
963 }
964 
965 static
966 char *netdev_feature_string(char *buf, char *end, const u8 *addr,
967 		      struct printf_spec spec)
968 {
969 	spec.flags |= SPECIAL | SMALL | ZEROPAD;
970 	if (spec.field_width == -1)
971 		spec.field_width = 2 + 2 * sizeof(netdev_features_t);
972 	spec.base = 16;
973 
974 	return number(buf, end, *(const netdev_features_t *)addr, spec);
975 }
976 
977 int kptr_restrict __read_mostly;
978 
979 /*
980  * Show a '%p' thing.  A kernel extension is that the '%p' is followed
981  * by an extra set of alphanumeric characters that are extended format
982  * specifiers.
983  *
984  * Right now we handle:
985  *
986  * - 'F' For symbolic function descriptor pointers with offset
987  * - 'f' For simple symbolic function names without offset
988  * - 'S' For symbolic direct pointers with offset
989  * - 's' For symbolic direct pointers without offset
990  * - 'B' For backtraced symbolic direct pointers with offset
991  * - 'R' For decoded struct resource, e.g., [mem 0x0-0x1f 64bit pref]
992  * - 'r' For raw struct resource, e.g., [mem 0x0-0x1f flags 0x201]
993  * - 'M' For a 6-byte MAC address, it prints the address in the
994  *       usual colon-separated hex notation
995  * - 'm' For a 6-byte MAC address, it prints the hex address without colons
996  * - 'MF' For a 6-byte MAC FDDI address, it prints the address
997  *       with a dash-separated hex notation
998  * - '[mM]R' For a 6-byte MAC address, Reverse order (Bluetooth)
999  * - 'I' [46] for IPv4/IPv6 addresses printed in the usual way
1000  *       IPv4 uses dot-separated decimal without leading 0's (1.2.3.4)
1001  *       IPv6 uses colon separated network-order 16 bit hex with leading 0's
1002  * - 'i' [46] for 'raw' IPv4/IPv6 addresses
1003  *       IPv6 omits the colons (01020304...0f)
1004  *       IPv4 uses dot-separated decimal with leading 0's (010.123.045.006)
1005  * - '[Ii]4[hnbl]' IPv4 addresses in host, network, big or little endian order
1006  * - 'I6c' for IPv6 addresses printed as specified by
1007  *       http://tools.ietf.org/html/rfc5952
1008  * - 'U' For a 16 byte UUID/GUID, it prints the UUID/GUID in the form
1009  *       "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
1010  *       Options for %pU are:
1011  *         b big endian lower case hex (default)
1012  *         B big endian UPPER case hex
1013  *         l little endian lower case hex
1014  *         L little endian UPPER case hex
1015  *           big endian output byte order is:
1016  *             [0][1][2][3]-[4][5]-[6][7]-[8][9]-[10][11][12][13][14][15]
1017  *           little endian output byte order is:
1018  *             [3][2][1][0]-[5][4]-[7][6]-[8][9]-[10][11][12][13][14][15]
1019  * - 'V' For a struct va_format which contains a format string * and va_list *,
1020  *       call vsnprintf(->format, *->va_list).
1021  *       Implements a "recursive vsnprintf".
1022  *       Do not use this feature without some mechanism to verify the
1023  *       correctness of the format string and va_list arguments.
1024  * - 'K' For a kernel pointer that should be hidden from unprivileged users
1025  * - 'NF' For a netdev_features_t
1026  * - 'h[CDN]' For a variable-length buffer, it prints it as a hex string with
1027  *            a certain separator (' ' by default):
1028  *              C colon
1029  *              D dash
1030  *              N no separator
1031  *            The maximum supported length is 64 bytes of the input. Consider
1032  *            to use print_hex_dump() for the larger input.
1033  * - 'a' For a phys_addr_t type and its derivative types (passed by reference)
1034  *
1035  * Note: The difference between 'S' and 'F' is that on ia64 and ppc64
1036  * function pointers are really function descriptors, which contain a
1037  * pointer to the real address.
1038  */
1039 static noinline_for_stack
1040 char *pointer(const char *fmt, char *buf, char *end, void *ptr,
1041 	      struct printf_spec spec)
1042 {
1043 	int default_width = 2 * sizeof(void *) + (spec.flags & SPECIAL ? 2 : 0);
1044 
1045 	if (!ptr && *fmt != 'K') {
1046 		/*
1047 		 * Print (null) with the same width as a pointer so it makes
1048 		 * tabular output look nice.
1049 		 */
1050 		if (spec.field_width == -1)
1051 			spec.field_width = default_width;
1052 		return string(buf, end, "(null)", spec);
1053 	}
1054 
1055 	switch (*fmt) {
1056 	case 'F':
1057 	case 'f':
1058 		ptr = dereference_function_descriptor(ptr);
1059 		/* Fallthrough */
1060 	case 'S':
1061 	case 's':
1062 	case 'B':
1063 		return symbol_string(buf, end, ptr, spec, *fmt);
1064 	case 'R':
1065 	case 'r':
1066 		return resource_string(buf, end, ptr, spec, fmt);
1067 	case 'h':
1068 		return hex_string(buf, end, ptr, spec, fmt);
1069 	case 'M':			/* Colon separated: 00:01:02:03:04:05 */
1070 	case 'm':			/* Contiguous: 000102030405 */
1071 					/* [mM]F (FDDI) */
1072 					/* [mM]R (Reverse order; Bluetooth) */
1073 		return mac_address_string(buf, end, ptr, spec, fmt);
1074 	case 'I':			/* Formatted IP supported
1075 					 * 4:	1.2.3.4
1076 					 * 6:	0001:0203:...:0708
1077 					 * 6c:	1::708 or 1::1.2.3.4
1078 					 */
1079 	case 'i':			/* Contiguous:
1080 					 * 4:	001.002.003.004
1081 					 * 6:   000102...0f
1082 					 */
1083 		switch (fmt[1]) {
1084 		case '6':
1085 			return ip6_addr_string(buf, end, ptr, spec, fmt);
1086 		case '4':
1087 			return ip4_addr_string(buf, end, ptr, spec, fmt);
1088 		}
1089 		break;
1090 	case 'U':
1091 		return uuid_string(buf, end, ptr, spec, fmt);
1092 	case 'V':
1093 		{
1094 			va_list va;
1095 
1096 			va_copy(va, *((struct va_format *)ptr)->va);
1097 			buf += vsnprintf(buf, end > buf ? end - buf : 0,
1098 					 ((struct va_format *)ptr)->fmt, va);
1099 			va_end(va);
1100 			return buf;
1101 		}
1102 	case 'K':
1103 		/*
1104 		 * %pK cannot be used in IRQ context because its test
1105 		 * for CAP_SYSLOG would be meaningless.
1106 		 */
1107 		if (kptr_restrict && (in_irq() || in_serving_softirq() ||
1108 				      in_nmi())) {
1109 			if (spec.field_width == -1)
1110 				spec.field_width = default_width;
1111 			return string(buf, end, "pK-error", spec);
1112 		}
1113 		if (!((kptr_restrict == 0) ||
1114 		      (kptr_restrict == 1 &&
1115 		       has_capability_noaudit(current, CAP_SYSLOG))))
1116 			ptr = NULL;
1117 		break;
1118 	case 'N':
1119 		switch (fmt[1]) {
1120 		case 'F':
1121 			return netdev_feature_string(buf, end, ptr, spec);
1122 		}
1123 		break;
1124 	case 'a':
1125 		spec.flags |= SPECIAL | SMALL | ZEROPAD;
1126 		spec.field_width = sizeof(phys_addr_t) * 2 + 2;
1127 		spec.base = 16;
1128 		return number(buf, end,
1129 			      (unsigned long long) *((phys_addr_t *)ptr), spec);
1130 	}
1131 	spec.flags |= SMALL;
1132 	if (spec.field_width == -1) {
1133 		spec.field_width = default_width;
1134 		spec.flags |= ZEROPAD;
1135 	}
1136 	spec.base = 16;
1137 
1138 	return number(buf, end, (unsigned long) ptr, spec);
1139 }
1140 
1141 /*
1142  * Helper function to decode printf style format.
1143  * Each call decode a token from the format and return the
1144  * number of characters read (or likely the delta where it wants
1145  * to go on the next call).
1146  * The decoded token is returned through the parameters
1147  *
1148  * 'h', 'l', or 'L' for integer fields
1149  * 'z' support added 23/7/1999 S.H.
1150  * 'z' changed to 'Z' --davidm 1/25/99
1151  * 't' added for ptrdiff_t
1152  *
1153  * @fmt: the format string
1154  * @type of the token returned
1155  * @flags: various flags such as +, -, # tokens..
1156  * @field_width: overwritten width
1157  * @base: base of the number (octal, hex, ...)
1158  * @precision: precision of a number
1159  * @qualifier: qualifier of a number (long, size_t, ...)
1160  */
1161 static noinline_for_stack
1162 int format_decode(const char *fmt, struct printf_spec *spec)
1163 {
1164 	const char *start = fmt;
1165 
1166 	/* we finished early by reading the field width */
1167 	if (spec->type == FORMAT_TYPE_WIDTH) {
1168 		if (spec->field_width < 0) {
1169 			spec->field_width = -spec->field_width;
1170 			spec->flags |= LEFT;
1171 		}
1172 		spec->type = FORMAT_TYPE_NONE;
1173 		goto precision;
1174 	}
1175 
1176 	/* we finished early by reading the precision */
1177 	if (spec->type == FORMAT_TYPE_PRECISION) {
1178 		if (spec->precision < 0)
1179 			spec->precision = 0;
1180 
1181 		spec->type = FORMAT_TYPE_NONE;
1182 		goto qualifier;
1183 	}
1184 
1185 	/* By default */
1186 	spec->type = FORMAT_TYPE_NONE;
1187 
1188 	for (; *fmt ; ++fmt) {
1189 		if (*fmt == '%')
1190 			break;
1191 	}
1192 
1193 	/* Return the current non-format string */
1194 	if (fmt != start || !*fmt)
1195 		return fmt - start;
1196 
1197 	/* Process flags */
1198 	spec->flags = 0;
1199 
1200 	while (1) { /* this also skips first '%' */
1201 		bool found = true;
1202 
1203 		++fmt;
1204 
1205 		switch (*fmt) {
1206 		case '-': spec->flags |= LEFT;    break;
1207 		case '+': spec->flags |= PLUS;    break;
1208 		case ' ': spec->flags |= SPACE;   break;
1209 		case '#': spec->flags |= SPECIAL; break;
1210 		case '0': spec->flags |= ZEROPAD; break;
1211 		default:  found = false;
1212 		}
1213 
1214 		if (!found)
1215 			break;
1216 	}
1217 
1218 	/* get field width */
1219 	spec->field_width = -1;
1220 
1221 	if (isdigit(*fmt))
1222 		spec->field_width = skip_atoi(&fmt);
1223 	else if (*fmt == '*') {
1224 		/* it's the next argument */
1225 		spec->type = FORMAT_TYPE_WIDTH;
1226 		return ++fmt - start;
1227 	}
1228 
1229 precision:
1230 	/* get the precision */
1231 	spec->precision = -1;
1232 	if (*fmt == '.') {
1233 		++fmt;
1234 		if (isdigit(*fmt)) {
1235 			spec->precision = skip_atoi(&fmt);
1236 			if (spec->precision < 0)
1237 				spec->precision = 0;
1238 		} else if (*fmt == '*') {
1239 			/* it's the next argument */
1240 			spec->type = FORMAT_TYPE_PRECISION;
1241 			return ++fmt - start;
1242 		}
1243 	}
1244 
1245 qualifier:
1246 	/* get the conversion qualifier */
1247 	spec->qualifier = -1;
1248 	if (*fmt == 'h' || _tolower(*fmt) == 'l' ||
1249 	    _tolower(*fmt) == 'z' || *fmt == 't') {
1250 		spec->qualifier = *fmt++;
1251 		if (unlikely(spec->qualifier == *fmt)) {
1252 			if (spec->qualifier == 'l') {
1253 				spec->qualifier = 'L';
1254 				++fmt;
1255 			} else if (spec->qualifier == 'h') {
1256 				spec->qualifier = 'H';
1257 				++fmt;
1258 			}
1259 		}
1260 	}
1261 
1262 	/* default base */
1263 	spec->base = 10;
1264 	switch (*fmt) {
1265 	case 'c':
1266 		spec->type = FORMAT_TYPE_CHAR;
1267 		return ++fmt - start;
1268 
1269 	case 's':
1270 		spec->type = FORMAT_TYPE_STR;
1271 		return ++fmt - start;
1272 
1273 	case 'p':
1274 		spec->type = FORMAT_TYPE_PTR;
1275 		return fmt - start;
1276 		/* skip alnum */
1277 
1278 	case 'n':
1279 		spec->type = FORMAT_TYPE_NRCHARS;
1280 		return ++fmt - start;
1281 
1282 	case '%':
1283 		spec->type = FORMAT_TYPE_PERCENT_CHAR;
1284 		return ++fmt - start;
1285 
1286 	/* integer number formats - set up the flags and "break" */
1287 	case 'o':
1288 		spec->base = 8;
1289 		break;
1290 
1291 	case 'x':
1292 		spec->flags |= SMALL;
1293 
1294 	case 'X':
1295 		spec->base = 16;
1296 		break;
1297 
1298 	case 'd':
1299 	case 'i':
1300 		spec->flags |= SIGN;
1301 	case 'u':
1302 		break;
1303 
1304 	default:
1305 		spec->type = FORMAT_TYPE_INVALID;
1306 		return fmt - start;
1307 	}
1308 
1309 	if (spec->qualifier == 'L')
1310 		spec->type = FORMAT_TYPE_LONG_LONG;
1311 	else if (spec->qualifier == 'l') {
1312 		if (spec->flags & SIGN)
1313 			spec->type = FORMAT_TYPE_LONG;
1314 		else
1315 			spec->type = FORMAT_TYPE_ULONG;
1316 	} else if (_tolower(spec->qualifier) == 'z') {
1317 		spec->type = FORMAT_TYPE_SIZE_T;
1318 	} else if (spec->qualifier == 't') {
1319 		spec->type = FORMAT_TYPE_PTRDIFF;
1320 	} else if (spec->qualifier == 'H') {
1321 		if (spec->flags & SIGN)
1322 			spec->type = FORMAT_TYPE_BYTE;
1323 		else
1324 			spec->type = FORMAT_TYPE_UBYTE;
1325 	} else if (spec->qualifier == 'h') {
1326 		if (spec->flags & SIGN)
1327 			spec->type = FORMAT_TYPE_SHORT;
1328 		else
1329 			spec->type = FORMAT_TYPE_USHORT;
1330 	} else {
1331 		if (spec->flags & SIGN)
1332 			spec->type = FORMAT_TYPE_INT;
1333 		else
1334 			spec->type = FORMAT_TYPE_UINT;
1335 	}
1336 
1337 	return ++fmt - start;
1338 }
1339 
1340 /**
1341  * vsnprintf - Format a string and place it in a buffer
1342  * @buf: The buffer to place the result into
1343  * @size: The size of the buffer, including the trailing null space
1344  * @fmt: The format string to use
1345  * @args: Arguments for the format string
1346  *
1347  * This function follows C99 vsnprintf, but has some extensions:
1348  * %pS output the name of a text symbol with offset
1349  * %ps output the name of a text symbol without offset
1350  * %pF output the name of a function pointer with its offset
1351  * %pf output the name of a function pointer without its offset
1352  * %pB output the name of a backtrace symbol with its offset
1353  * %pR output the address range in a struct resource with decoded flags
1354  * %pr output the address range in a struct resource with raw flags
1355  * %pM output a 6-byte MAC address with colons
1356  * %pMR output a 6-byte MAC address with colons in reversed order
1357  * %pMF output a 6-byte MAC address with dashes
1358  * %pm output a 6-byte MAC address without colons
1359  * %pmR output a 6-byte MAC address without colons in reversed order
1360  * %pI4 print an IPv4 address without leading zeros
1361  * %pi4 print an IPv4 address with leading zeros
1362  * %pI6 print an IPv6 address with colons
1363  * %pi6 print an IPv6 address without colons
1364  * %pI6c print an IPv6 address as specified by RFC 5952
1365  * %pU[bBlL] print a UUID/GUID in big or little endian using lower or upper
1366  *   case.
1367  * %*ph[CDN] a variable-length hex string with a separator (supports up to 64
1368  *           bytes of the input)
1369  * %n is ignored
1370  *
1371  * ** Please update Documentation/printk-formats.txt when making changes **
1372  *
1373  * The return value is the number of characters which would
1374  * be generated for the given input, excluding the trailing
1375  * '\0', as per ISO C99. If you want to have the exact
1376  * number of characters written into @buf as return value
1377  * (not including the trailing '\0'), use vscnprintf(). If the
1378  * return is greater than or equal to @size, the resulting
1379  * string is truncated.
1380  *
1381  * If you're not already dealing with a va_list consider using snprintf().
1382  */
1383 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
1384 {
1385 	unsigned long long num;
1386 	char *str, *end;
1387 	struct printf_spec spec = {0};
1388 
1389 	/* Reject out-of-range values early.  Large positive sizes are
1390 	   used for unknown buffer sizes. */
1391 	if (WARN_ON_ONCE((int) size < 0))
1392 		return 0;
1393 
1394 	str = buf;
1395 	end = buf + size;
1396 
1397 	/* Make sure end is always >= buf */
1398 	if (end < buf) {
1399 		end = ((void *)-1);
1400 		size = end - buf;
1401 	}
1402 
1403 	while (*fmt) {
1404 		const char *old_fmt = fmt;
1405 		int read = format_decode(fmt, &spec);
1406 
1407 		fmt += read;
1408 
1409 		switch (spec.type) {
1410 		case FORMAT_TYPE_NONE: {
1411 			int copy = read;
1412 			if (str < end) {
1413 				if (copy > end - str)
1414 					copy = end - str;
1415 				memcpy(str, old_fmt, copy);
1416 			}
1417 			str += read;
1418 			break;
1419 		}
1420 
1421 		case FORMAT_TYPE_WIDTH:
1422 			spec.field_width = va_arg(args, int);
1423 			break;
1424 
1425 		case FORMAT_TYPE_PRECISION:
1426 			spec.precision = va_arg(args, int);
1427 			break;
1428 
1429 		case FORMAT_TYPE_CHAR: {
1430 			char c;
1431 
1432 			if (!(spec.flags & LEFT)) {
1433 				while (--spec.field_width > 0) {
1434 					if (str < end)
1435 						*str = ' ';
1436 					++str;
1437 
1438 				}
1439 			}
1440 			c = (unsigned char) va_arg(args, int);
1441 			if (str < end)
1442 				*str = c;
1443 			++str;
1444 			while (--spec.field_width > 0) {
1445 				if (str < end)
1446 					*str = ' ';
1447 				++str;
1448 			}
1449 			break;
1450 		}
1451 
1452 		case FORMAT_TYPE_STR:
1453 			str = string(str, end, va_arg(args, char *), spec);
1454 			break;
1455 
1456 		case FORMAT_TYPE_PTR:
1457 			str = pointer(fmt+1, str, end, va_arg(args, void *),
1458 				      spec);
1459 			while (isalnum(*fmt))
1460 				fmt++;
1461 			break;
1462 
1463 		case FORMAT_TYPE_PERCENT_CHAR:
1464 			if (str < end)
1465 				*str = '%';
1466 			++str;
1467 			break;
1468 
1469 		case FORMAT_TYPE_INVALID:
1470 			if (str < end)
1471 				*str = '%';
1472 			++str;
1473 			break;
1474 
1475 		case FORMAT_TYPE_NRCHARS: {
1476 			u8 qualifier = spec.qualifier;
1477 
1478 			if (qualifier == 'l') {
1479 				long *ip = va_arg(args, long *);
1480 				*ip = (str - buf);
1481 			} else if (_tolower(qualifier) == 'z') {
1482 				size_t *ip = va_arg(args, size_t *);
1483 				*ip = (str - buf);
1484 			} else {
1485 				int *ip = va_arg(args, int *);
1486 				*ip = (str - buf);
1487 			}
1488 			break;
1489 		}
1490 
1491 		default:
1492 			switch (spec.type) {
1493 			case FORMAT_TYPE_LONG_LONG:
1494 				num = va_arg(args, long long);
1495 				break;
1496 			case FORMAT_TYPE_ULONG:
1497 				num = va_arg(args, unsigned long);
1498 				break;
1499 			case FORMAT_TYPE_LONG:
1500 				num = va_arg(args, long);
1501 				break;
1502 			case FORMAT_TYPE_SIZE_T:
1503 				if (spec.flags & SIGN)
1504 					num = va_arg(args, ssize_t);
1505 				else
1506 					num = va_arg(args, size_t);
1507 				break;
1508 			case FORMAT_TYPE_PTRDIFF:
1509 				num = va_arg(args, ptrdiff_t);
1510 				break;
1511 			case FORMAT_TYPE_UBYTE:
1512 				num = (unsigned char) va_arg(args, int);
1513 				break;
1514 			case FORMAT_TYPE_BYTE:
1515 				num = (signed char) va_arg(args, int);
1516 				break;
1517 			case FORMAT_TYPE_USHORT:
1518 				num = (unsigned short) va_arg(args, int);
1519 				break;
1520 			case FORMAT_TYPE_SHORT:
1521 				num = (short) va_arg(args, int);
1522 				break;
1523 			case FORMAT_TYPE_INT:
1524 				num = (int) va_arg(args, int);
1525 				break;
1526 			default:
1527 				num = va_arg(args, unsigned int);
1528 			}
1529 
1530 			str = number(str, end, num, spec);
1531 		}
1532 	}
1533 
1534 	if (size > 0) {
1535 		if (str < end)
1536 			*str = '\0';
1537 		else
1538 			end[-1] = '\0';
1539 	}
1540 
1541 	/* the trailing null byte doesn't count towards the total */
1542 	return str-buf;
1543 
1544 }
1545 EXPORT_SYMBOL(vsnprintf);
1546 
1547 /**
1548  * vscnprintf - Format a string and place it in a buffer
1549  * @buf: The buffer to place the result into
1550  * @size: The size of the buffer, including the trailing null space
1551  * @fmt: The format string to use
1552  * @args: Arguments for the format string
1553  *
1554  * The return value is the number of characters which have been written into
1555  * the @buf not including the trailing '\0'. If @size is == 0 the function
1556  * returns 0.
1557  *
1558  * If you're not already dealing with a va_list consider using scnprintf().
1559  *
1560  * See the vsnprintf() documentation for format string extensions over C99.
1561  */
1562 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
1563 {
1564 	int i;
1565 
1566 	i = vsnprintf(buf, size, fmt, args);
1567 
1568 	if (likely(i < size))
1569 		return i;
1570 	if (size != 0)
1571 		return size - 1;
1572 	return 0;
1573 }
1574 EXPORT_SYMBOL(vscnprintf);
1575 
1576 /**
1577  * snprintf - Format a string and place it in a buffer
1578  * @buf: The buffer to place the result into
1579  * @size: The size of the buffer, including the trailing null space
1580  * @fmt: The format string to use
1581  * @...: Arguments for the format string
1582  *
1583  * The return value is the number of characters which would be
1584  * generated for the given input, excluding the trailing null,
1585  * as per ISO C99.  If the return is greater than or equal to
1586  * @size, the resulting string is truncated.
1587  *
1588  * See the vsnprintf() documentation for format string extensions over C99.
1589  */
1590 int snprintf(char *buf, size_t size, const char *fmt, ...)
1591 {
1592 	va_list args;
1593 	int i;
1594 
1595 	va_start(args, fmt);
1596 	i = vsnprintf(buf, size, fmt, args);
1597 	va_end(args);
1598 
1599 	return i;
1600 }
1601 EXPORT_SYMBOL(snprintf);
1602 
1603 /**
1604  * scnprintf - Format a string and place it in a buffer
1605  * @buf: The buffer to place the result into
1606  * @size: The size of the buffer, including the trailing null space
1607  * @fmt: The format string to use
1608  * @...: Arguments for the format string
1609  *
1610  * The return value is the number of characters written into @buf not including
1611  * the trailing '\0'. If @size is == 0 the function returns 0.
1612  */
1613 
1614 int scnprintf(char *buf, size_t size, const char *fmt, ...)
1615 {
1616 	va_list args;
1617 	int i;
1618 
1619 	va_start(args, fmt);
1620 	i = vscnprintf(buf, size, fmt, args);
1621 	va_end(args);
1622 
1623 	return i;
1624 }
1625 EXPORT_SYMBOL(scnprintf);
1626 
1627 /**
1628  * vsprintf - Format a string and place it in a buffer
1629  * @buf: The buffer to place the result into
1630  * @fmt: The format string to use
1631  * @args: Arguments for the format string
1632  *
1633  * The function returns the number of characters written
1634  * into @buf. Use vsnprintf() or vscnprintf() in order to avoid
1635  * buffer overflows.
1636  *
1637  * If you're not already dealing with a va_list consider using sprintf().
1638  *
1639  * See the vsnprintf() documentation for format string extensions over C99.
1640  */
1641 int vsprintf(char *buf, const char *fmt, va_list args)
1642 {
1643 	return vsnprintf(buf, INT_MAX, fmt, args);
1644 }
1645 EXPORT_SYMBOL(vsprintf);
1646 
1647 /**
1648  * sprintf - Format a string and place it in a buffer
1649  * @buf: The buffer to place the result into
1650  * @fmt: The format string to use
1651  * @...: Arguments for the format string
1652  *
1653  * The function returns the number of characters written
1654  * into @buf. Use snprintf() or scnprintf() in order to avoid
1655  * buffer overflows.
1656  *
1657  * See the vsnprintf() documentation for format string extensions over C99.
1658  */
1659 int sprintf(char *buf, const char *fmt, ...)
1660 {
1661 	va_list args;
1662 	int i;
1663 
1664 	va_start(args, fmt);
1665 	i = vsnprintf(buf, INT_MAX, fmt, args);
1666 	va_end(args);
1667 
1668 	return i;
1669 }
1670 EXPORT_SYMBOL(sprintf);
1671 
1672 #ifdef CONFIG_BINARY_PRINTF
1673 /*
1674  * bprintf service:
1675  * vbin_printf() - VA arguments to binary data
1676  * bstr_printf() - Binary data to text string
1677  */
1678 
1679 /**
1680  * vbin_printf - Parse a format string and place args' binary value in a buffer
1681  * @bin_buf: The buffer to place args' binary value
1682  * @size: The size of the buffer(by words(32bits), not characters)
1683  * @fmt: The format string to use
1684  * @args: Arguments for the format string
1685  *
1686  * The format follows C99 vsnprintf, except %n is ignored, and its argument
1687  * is skiped.
1688  *
1689  * The return value is the number of words(32bits) which would be generated for
1690  * the given input.
1691  *
1692  * NOTE:
1693  * If the return value is greater than @size, the resulting bin_buf is NOT
1694  * valid for bstr_printf().
1695  */
1696 int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args)
1697 {
1698 	struct printf_spec spec = {0};
1699 	char *str, *end;
1700 
1701 	str = (char *)bin_buf;
1702 	end = (char *)(bin_buf + size);
1703 
1704 #define save_arg(type)							\
1705 do {									\
1706 	if (sizeof(type) == 8) {					\
1707 		unsigned long long value;				\
1708 		str = PTR_ALIGN(str, sizeof(u32));			\
1709 		value = va_arg(args, unsigned long long);		\
1710 		if (str + sizeof(type) <= end) {			\
1711 			*(u32 *)str = *(u32 *)&value;			\
1712 			*(u32 *)(str + 4) = *((u32 *)&value + 1);	\
1713 		}							\
1714 	} else {							\
1715 		unsigned long value;					\
1716 		str = PTR_ALIGN(str, sizeof(type));			\
1717 		value = va_arg(args, int);				\
1718 		if (str + sizeof(type) <= end)				\
1719 			*(typeof(type) *)str = (type)value;		\
1720 	}								\
1721 	str += sizeof(type);						\
1722 } while (0)
1723 
1724 	while (*fmt) {
1725 		int read = format_decode(fmt, &spec);
1726 
1727 		fmt += read;
1728 
1729 		switch (spec.type) {
1730 		case FORMAT_TYPE_NONE:
1731 		case FORMAT_TYPE_INVALID:
1732 		case FORMAT_TYPE_PERCENT_CHAR:
1733 			break;
1734 
1735 		case FORMAT_TYPE_WIDTH:
1736 		case FORMAT_TYPE_PRECISION:
1737 			save_arg(int);
1738 			break;
1739 
1740 		case FORMAT_TYPE_CHAR:
1741 			save_arg(char);
1742 			break;
1743 
1744 		case FORMAT_TYPE_STR: {
1745 			const char *save_str = va_arg(args, char *);
1746 			size_t len;
1747 
1748 			if ((unsigned long)save_str > (unsigned long)-PAGE_SIZE
1749 					|| (unsigned long)save_str < PAGE_SIZE)
1750 				save_str = "(null)";
1751 			len = strlen(save_str) + 1;
1752 			if (str + len < end)
1753 				memcpy(str, save_str, len);
1754 			str += len;
1755 			break;
1756 		}
1757 
1758 		case FORMAT_TYPE_PTR:
1759 			save_arg(void *);
1760 			/* skip all alphanumeric pointer suffixes */
1761 			while (isalnum(*fmt))
1762 				fmt++;
1763 			break;
1764 
1765 		case FORMAT_TYPE_NRCHARS: {
1766 			/* skip %n 's argument */
1767 			u8 qualifier = spec.qualifier;
1768 			void *skip_arg;
1769 			if (qualifier == 'l')
1770 				skip_arg = va_arg(args, long *);
1771 			else if (_tolower(qualifier) == 'z')
1772 				skip_arg = va_arg(args, size_t *);
1773 			else
1774 				skip_arg = va_arg(args, int *);
1775 			break;
1776 		}
1777 
1778 		default:
1779 			switch (spec.type) {
1780 
1781 			case FORMAT_TYPE_LONG_LONG:
1782 				save_arg(long long);
1783 				break;
1784 			case FORMAT_TYPE_ULONG:
1785 			case FORMAT_TYPE_LONG:
1786 				save_arg(unsigned long);
1787 				break;
1788 			case FORMAT_TYPE_SIZE_T:
1789 				save_arg(size_t);
1790 				break;
1791 			case FORMAT_TYPE_PTRDIFF:
1792 				save_arg(ptrdiff_t);
1793 				break;
1794 			case FORMAT_TYPE_UBYTE:
1795 			case FORMAT_TYPE_BYTE:
1796 				save_arg(char);
1797 				break;
1798 			case FORMAT_TYPE_USHORT:
1799 			case FORMAT_TYPE_SHORT:
1800 				save_arg(short);
1801 				break;
1802 			default:
1803 				save_arg(int);
1804 			}
1805 		}
1806 	}
1807 
1808 	return (u32 *)(PTR_ALIGN(str, sizeof(u32))) - bin_buf;
1809 #undef save_arg
1810 }
1811 EXPORT_SYMBOL_GPL(vbin_printf);
1812 
1813 /**
1814  * bstr_printf - Format a string from binary arguments and place it in a buffer
1815  * @buf: The buffer to place the result into
1816  * @size: The size of the buffer, including the trailing null space
1817  * @fmt: The format string to use
1818  * @bin_buf: Binary arguments for the format string
1819  *
1820  * This function like C99 vsnprintf, but the difference is that vsnprintf gets
1821  * arguments from stack, and bstr_printf gets arguments from @bin_buf which is
1822  * a binary buffer that generated by vbin_printf.
1823  *
1824  * The format follows C99 vsnprintf, but has some extensions:
1825  *  see vsnprintf comment for details.
1826  *
1827  * The return value is the number of characters which would
1828  * be generated for the given input, excluding the trailing
1829  * '\0', as per ISO C99. If you want to have the exact
1830  * number of characters written into @buf as return value
1831  * (not including the trailing '\0'), use vscnprintf(). If the
1832  * return is greater than or equal to @size, the resulting
1833  * string is truncated.
1834  */
1835 int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf)
1836 {
1837 	struct printf_spec spec = {0};
1838 	char *str, *end;
1839 	const char *args = (const char *)bin_buf;
1840 
1841 	if (WARN_ON_ONCE((int) size < 0))
1842 		return 0;
1843 
1844 	str = buf;
1845 	end = buf + size;
1846 
1847 #define get_arg(type)							\
1848 ({									\
1849 	typeof(type) value;						\
1850 	if (sizeof(type) == 8) {					\
1851 		args = PTR_ALIGN(args, sizeof(u32));			\
1852 		*(u32 *)&value = *(u32 *)args;				\
1853 		*((u32 *)&value + 1) = *(u32 *)(args + 4);		\
1854 	} else {							\
1855 		args = PTR_ALIGN(args, sizeof(type));			\
1856 		value = *(typeof(type) *)args;				\
1857 	}								\
1858 	args += sizeof(type);						\
1859 	value;								\
1860 })
1861 
1862 	/* Make sure end is always >= buf */
1863 	if (end < buf) {
1864 		end = ((void *)-1);
1865 		size = end - buf;
1866 	}
1867 
1868 	while (*fmt) {
1869 		const char *old_fmt = fmt;
1870 		int read = format_decode(fmt, &spec);
1871 
1872 		fmt += read;
1873 
1874 		switch (spec.type) {
1875 		case FORMAT_TYPE_NONE: {
1876 			int copy = read;
1877 			if (str < end) {
1878 				if (copy > end - str)
1879 					copy = end - str;
1880 				memcpy(str, old_fmt, copy);
1881 			}
1882 			str += read;
1883 			break;
1884 		}
1885 
1886 		case FORMAT_TYPE_WIDTH:
1887 			spec.field_width = get_arg(int);
1888 			break;
1889 
1890 		case FORMAT_TYPE_PRECISION:
1891 			spec.precision = get_arg(int);
1892 			break;
1893 
1894 		case FORMAT_TYPE_CHAR: {
1895 			char c;
1896 
1897 			if (!(spec.flags & LEFT)) {
1898 				while (--spec.field_width > 0) {
1899 					if (str < end)
1900 						*str = ' ';
1901 					++str;
1902 				}
1903 			}
1904 			c = (unsigned char) get_arg(char);
1905 			if (str < end)
1906 				*str = c;
1907 			++str;
1908 			while (--spec.field_width > 0) {
1909 				if (str < end)
1910 					*str = ' ';
1911 				++str;
1912 			}
1913 			break;
1914 		}
1915 
1916 		case FORMAT_TYPE_STR: {
1917 			const char *str_arg = args;
1918 			args += strlen(str_arg) + 1;
1919 			str = string(str, end, (char *)str_arg, spec);
1920 			break;
1921 		}
1922 
1923 		case FORMAT_TYPE_PTR:
1924 			str = pointer(fmt+1, str, end, get_arg(void *), spec);
1925 			while (isalnum(*fmt))
1926 				fmt++;
1927 			break;
1928 
1929 		case FORMAT_TYPE_PERCENT_CHAR:
1930 		case FORMAT_TYPE_INVALID:
1931 			if (str < end)
1932 				*str = '%';
1933 			++str;
1934 			break;
1935 
1936 		case FORMAT_TYPE_NRCHARS:
1937 			/* skip */
1938 			break;
1939 
1940 		default: {
1941 			unsigned long long num;
1942 
1943 			switch (spec.type) {
1944 
1945 			case FORMAT_TYPE_LONG_LONG:
1946 				num = get_arg(long long);
1947 				break;
1948 			case FORMAT_TYPE_ULONG:
1949 			case FORMAT_TYPE_LONG:
1950 				num = get_arg(unsigned long);
1951 				break;
1952 			case FORMAT_TYPE_SIZE_T:
1953 				num = get_arg(size_t);
1954 				break;
1955 			case FORMAT_TYPE_PTRDIFF:
1956 				num = get_arg(ptrdiff_t);
1957 				break;
1958 			case FORMAT_TYPE_UBYTE:
1959 				num = get_arg(unsigned char);
1960 				break;
1961 			case FORMAT_TYPE_BYTE:
1962 				num = get_arg(signed char);
1963 				break;
1964 			case FORMAT_TYPE_USHORT:
1965 				num = get_arg(unsigned short);
1966 				break;
1967 			case FORMAT_TYPE_SHORT:
1968 				num = get_arg(short);
1969 				break;
1970 			case FORMAT_TYPE_UINT:
1971 				num = get_arg(unsigned int);
1972 				break;
1973 			default:
1974 				num = get_arg(int);
1975 			}
1976 
1977 			str = number(str, end, num, spec);
1978 		} /* default: */
1979 		} /* switch(spec.type) */
1980 	} /* while(*fmt) */
1981 
1982 	if (size > 0) {
1983 		if (str < end)
1984 			*str = '\0';
1985 		else
1986 			end[-1] = '\0';
1987 	}
1988 
1989 #undef get_arg
1990 
1991 	/* the trailing null byte doesn't count towards the total */
1992 	return str - buf;
1993 }
1994 EXPORT_SYMBOL_GPL(bstr_printf);
1995 
1996 /**
1997  * bprintf - Parse a format string and place args' binary value in a buffer
1998  * @bin_buf: The buffer to place args' binary value
1999  * @size: The size of the buffer(by words(32bits), not characters)
2000  * @fmt: The format string to use
2001  * @...: Arguments for the format string
2002  *
2003  * The function returns the number of words(u32) written
2004  * into @bin_buf.
2005  */
2006 int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...)
2007 {
2008 	va_list args;
2009 	int ret;
2010 
2011 	va_start(args, fmt);
2012 	ret = vbin_printf(bin_buf, size, fmt, args);
2013 	va_end(args);
2014 
2015 	return ret;
2016 }
2017 EXPORT_SYMBOL_GPL(bprintf);
2018 
2019 #endif /* CONFIG_BINARY_PRINTF */
2020 
2021 /**
2022  * vsscanf - Unformat a buffer into a list of arguments
2023  * @buf:	input buffer
2024  * @fmt:	format of buffer
2025  * @args:	arguments
2026  */
2027 int vsscanf(const char *buf, const char *fmt, va_list args)
2028 {
2029 	const char *str = buf;
2030 	char *next;
2031 	char digit;
2032 	int num = 0;
2033 	u8 qualifier;
2034 	unsigned int base;
2035 	union {
2036 		long long s;
2037 		unsigned long long u;
2038 	} val;
2039 	s16 field_width;
2040 	bool is_sign;
2041 
2042 	while (*fmt) {
2043 		/* skip any white space in format */
2044 		/* white space in format matchs any amount of
2045 		 * white space, including none, in the input.
2046 		 */
2047 		if (isspace(*fmt)) {
2048 			fmt = skip_spaces(++fmt);
2049 			str = skip_spaces(str);
2050 		}
2051 
2052 		/* anything that is not a conversion must match exactly */
2053 		if (*fmt != '%' && *fmt) {
2054 			if (*fmt++ != *str++)
2055 				break;
2056 			continue;
2057 		}
2058 
2059 		if (!*fmt)
2060 			break;
2061 		++fmt;
2062 
2063 		/* skip this conversion.
2064 		 * advance both strings to next white space
2065 		 */
2066 		if (*fmt == '*') {
2067 			if (!*str)
2068 				break;
2069 			while (!isspace(*fmt) && *fmt != '%' && *fmt)
2070 				fmt++;
2071 			while (!isspace(*str) && *str)
2072 				str++;
2073 			continue;
2074 		}
2075 
2076 		/* get field width */
2077 		field_width = -1;
2078 		if (isdigit(*fmt)) {
2079 			field_width = skip_atoi(&fmt);
2080 			if (field_width <= 0)
2081 				break;
2082 		}
2083 
2084 		/* get conversion qualifier */
2085 		qualifier = -1;
2086 		if (*fmt == 'h' || _tolower(*fmt) == 'l' ||
2087 		    _tolower(*fmt) == 'z') {
2088 			qualifier = *fmt++;
2089 			if (unlikely(qualifier == *fmt)) {
2090 				if (qualifier == 'h') {
2091 					qualifier = 'H';
2092 					fmt++;
2093 				} else if (qualifier == 'l') {
2094 					qualifier = 'L';
2095 					fmt++;
2096 				}
2097 			}
2098 		}
2099 
2100 		if (!*fmt)
2101 			break;
2102 
2103 		if (*fmt == 'n') {
2104 			/* return number of characters read so far */
2105 			*va_arg(args, int *) = str - buf;
2106 			++fmt;
2107 			continue;
2108 		}
2109 
2110 		if (!*str)
2111 			break;
2112 
2113 		base = 10;
2114 		is_sign = 0;
2115 
2116 		switch (*fmt++) {
2117 		case 'c':
2118 		{
2119 			char *s = (char *)va_arg(args, char*);
2120 			if (field_width == -1)
2121 				field_width = 1;
2122 			do {
2123 				*s++ = *str++;
2124 			} while (--field_width > 0 && *str);
2125 			num++;
2126 		}
2127 		continue;
2128 		case 's':
2129 		{
2130 			char *s = (char *)va_arg(args, char *);
2131 			if (field_width == -1)
2132 				field_width = SHRT_MAX;
2133 			/* first, skip leading white space in buffer */
2134 			str = skip_spaces(str);
2135 
2136 			/* now copy until next white space */
2137 			while (*str && !isspace(*str) && field_width--)
2138 				*s++ = *str++;
2139 			*s = '\0';
2140 			num++;
2141 		}
2142 		continue;
2143 		case 'o':
2144 			base = 8;
2145 			break;
2146 		case 'x':
2147 		case 'X':
2148 			base = 16;
2149 			break;
2150 		case 'i':
2151 			base = 0;
2152 		case 'd':
2153 			is_sign = 1;
2154 		case 'u':
2155 			break;
2156 		case '%':
2157 			/* looking for '%' in str */
2158 			if (*str++ != '%')
2159 				return num;
2160 			continue;
2161 		default:
2162 			/* invalid format; stop here */
2163 			return num;
2164 		}
2165 
2166 		/* have some sort of integer conversion.
2167 		 * first, skip white space in buffer.
2168 		 */
2169 		str = skip_spaces(str);
2170 
2171 		digit = *str;
2172 		if (is_sign && digit == '-')
2173 			digit = *(str + 1);
2174 
2175 		if (!digit
2176 		    || (base == 16 && !isxdigit(digit))
2177 		    || (base == 10 && !isdigit(digit))
2178 		    || (base == 8 && (!isdigit(digit) || digit > '7'))
2179 		    || (base == 0 && !isdigit(digit)))
2180 			break;
2181 
2182 		if (is_sign)
2183 			val.s = qualifier != 'L' ?
2184 				simple_strtol(str, &next, base) :
2185 				simple_strtoll(str, &next, base);
2186 		else
2187 			val.u = qualifier != 'L' ?
2188 				simple_strtoul(str, &next, base) :
2189 				simple_strtoull(str, &next, base);
2190 
2191 		if (field_width > 0 && next - str > field_width) {
2192 			if (base == 0)
2193 				_parse_integer_fixup_radix(str, &base);
2194 			while (next - str > field_width) {
2195 				if (is_sign)
2196 					val.s = div_s64(val.s, base);
2197 				else
2198 					val.u = div_u64(val.u, base);
2199 				--next;
2200 			}
2201 		}
2202 
2203 		switch (qualifier) {
2204 		case 'H':	/* that's 'hh' in format */
2205 			if (is_sign)
2206 				*va_arg(args, signed char *) = val.s;
2207 			else
2208 				*va_arg(args, unsigned char *) = val.u;
2209 			break;
2210 		case 'h':
2211 			if (is_sign)
2212 				*va_arg(args, short *) = val.s;
2213 			else
2214 				*va_arg(args, unsigned short *) = val.u;
2215 			break;
2216 		case 'l':
2217 			if (is_sign)
2218 				*va_arg(args, long *) = val.s;
2219 			else
2220 				*va_arg(args, unsigned long *) = val.u;
2221 			break;
2222 		case 'L':
2223 			if (is_sign)
2224 				*va_arg(args, long long *) = val.s;
2225 			else
2226 				*va_arg(args, unsigned long long *) = val.u;
2227 			break;
2228 		case 'Z':
2229 		case 'z':
2230 			*va_arg(args, size_t *) = val.u;
2231 			break;
2232 		default:
2233 			if (is_sign)
2234 				*va_arg(args, int *) = val.s;
2235 			else
2236 				*va_arg(args, unsigned int *) = val.u;
2237 			break;
2238 		}
2239 		num++;
2240 
2241 		if (!next)
2242 			break;
2243 		str = next;
2244 	}
2245 
2246 	return num;
2247 }
2248 EXPORT_SYMBOL(vsscanf);
2249 
2250 /**
2251  * sscanf - Unformat a buffer into a list of arguments
2252  * @buf:	input buffer
2253  * @fmt:	formatting of buffer
2254  * @...:	resulting arguments
2255  */
2256 int sscanf(const char *buf, const char *fmt, ...)
2257 {
2258 	va_list args;
2259 	int i;
2260 
2261 	va_start(args, fmt);
2262 	i = vsscanf(buf, fmt, args);
2263 	va_end(args);
2264 
2265 	return i;
2266 }
2267 EXPORT_SYMBOL(sscanf);
2268