xref: /openbmc/linux/lib/vsprintf.c (revision 2c684d89)
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/clk.h>
21 #include <linux/clk-provider.h>
22 #include <linux/module.h>	/* for KSYM_SYMBOL_LEN */
23 #include <linux/types.h>
24 #include <linux/string.h>
25 #include <linux/ctype.h>
26 #include <linux/kernel.h>
27 #include <linux/kallsyms.h>
28 #include <linux/math64.h>
29 #include <linux/uaccess.h>
30 #include <linux/ioport.h>
31 #include <linux/dcache.h>
32 #include <linux/cred.h>
33 #include <net/addrconf.h>
34 
35 #include <asm/page.h>		/* for PAGE_SIZE */
36 #include <asm/sections.h>	/* for dereference_function_descriptor() */
37 #include <asm/byteorder.h>	/* cpu_to_le16 */
38 
39 #include <linux/string_helpers.h>
40 #include "kstrtox.h"
41 
42 /**
43  * simple_strtoull - convert a string to an unsigned long long
44  * @cp: The start of the string
45  * @endp: A pointer to the end of the parsed string will be placed here
46  * @base: The number base to use
47  *
48  * This function is obsolete. Please use kstrtoull instead.
49  */
50 unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base)
51 {
52 	unsigned long long result;
53 	unsigned int rv;
54 
55 	cp = _parse_integer_fixup_radix(cp, &base);
56 	rv = _parse_integer(cp, base, &result);
57 	/* FIXME */
58 	cp += (rv & ~KSTRTOX_OVERFLOW);
59 
60 	if (endp)
61 		*endp = (char *)cp;
62 
63 	return result;
64 }
65 EXPORT_SYMBOL(simple_strtoull);
66 
67 /**
68  * simple_strtoul - convert a string to an unsigned long
69  * @cp: The start of the string
70  * @endp: A pointer to the end of the parsed string will be placed here
71  * @base: The number base to use
72  *
73  * This function is obsolete. Please use kstrtoul instead.
74  */
75 unsigned long simple_strtoul(const char *cp, char **endp, unsigned int base)
76 {
77 	return simple_strtoull(cp, endp, base);
78 }
79 EXPORT_SYMBOL(simple_strtoul);
80 
81 /**
82  * simple_strtol - convert a string to a signed long
83  * @cp: The start of the string
84  * @endp: A pointer to the end of the parsed string will be placed here
85  * @base: The number base to use
86  *
87  * This function is obsolete. Please use kstrtol instead.
88  */
89 long simple_strtol(const char *cp, char **endp, unsigned int base)
90 {
91 	if (*cp == '-')
92 		return -simple_strtoul(cp + 1, endp, base);
93 
94 	return simple_strtoul(cp, endp, base);
95 }
96 EXPORT_SYMBOL(simple_strtol);
97 
98 /**
99  * simple_strtoll - convert a string to a signed long long
100  * @cp: The start of the string
101  * @endp: A pointer to the end of the parsed string will be placed here
102  * @base: The number base to use
103  *
104  * This function is obsolete. Please use kstrtoll instead.
105  */
106 long long simple_strtoll(const char *cp, char **endp, unsigned int base)
107 {
108 	if (*cp == '-')
109 		return -simple_strtoull(cp + 1, endp, base);
110 
111 	return simple_strtoull(cp, endp, base);
112 }
113 EXPORT_SYMBOL(simple_strtoll);
114 
115 static noinline_for_stack
116 int skip_atoi(const char **s)
117 {
118 	int i = 0;
119 
120 	do {
121 		i = i*10 + *((*s)++) - '0';
122 	} while (isdigit(**s));
123 
124 	return i;
125 }
126 
127 /*
128  * Decimal conversion is by far the most typical, and is used for
129  * /proc and /sys data. This directly impacts e.g. top performance
130  * with many processes running. We optimize it for speed by emitting
131  * two characters at a time, using a 200 byte lookup table. This
132  * roughly halves the number of multiplications compared to computing
133  * the digits one at a time. Implementation strongly inspired by the
134  * previous version, which in turn used ideas described at
135  * <http://www.cs.uiowa.edu/~jones/bcd/divide.html> (with permission
136  * from the author, Douglas W. Jones).
137  *
138  * It turns out there is precisely one 26 bit fixed-point
139  * approximation a of 64/100 for which x/100 == (x * (u64)a) >> 32
140  * holds for all x in [0, 10^8-1], namely a = 0x28f5c29. The actual
141  * range happens to be somewhat larger (x <= 1073741898), but that's
142  * irrelevant for our purpose.
143  *
144  * For dividing a number in the range [10^4, 10^6-1] by 100, we still
145  * need a 32x32->64 bit multiply, so we simply use the same constant.
146  *
147  * For dividing a number in the range [100, 10^4-1] by 100, there are
148  * several options. The simplest is (x * 0x147b) >> 19, which is valid
149  * for all x <= 43698.
150  */
151 
152 static const u16 decpair[100] = {
153 #define _(x) (__force u16) cpu_to_le16(((x % 10) | ((x / 10) << 8)) + 0x3030)
154 	_( 0), _( 1), _( 2), _( 3), _( 4), _( 5), _( 6), _( 7), _( 8), _( 9),
155 	_(10), _(11), _(12), _(13), _(14), _(15), _(16), _(17), _(18), _(19),
156 	_(20), _(21), _(22), _(23), _(24), _(25), _(26), _(27), _(28), _(29),
157 	_(30), _(31), _(32), _(33), _(34), _(35), _(36), _(37), _(38), _(39),
158 	_(40), _(41), _(42), _(43), _(44), _(45), _(46), _(47), _(48), _(49),
159 	_(50), _(51), _(52), _(53), _(54), _(55), _(56), _(57), _(58), _(59),
160 	_(60), _(61), _(62), _(63), _(64), _(65), _(66), _(67), _(68), _(69),
161 	_(70), _(71), _(72), _(73), _(74), _(75), _(76), _(77), _(78), _(79),
162 	_(80), _(81), _(82), _(83), _(84), _(85), _(86), _(87), _(88), _(89),
163 	_(90), _(91), _(92), _(93), _(94), _(95), _(96), _(97), _(98), _(99),
164 #undef _
165 };
166 
167 /*
168  * This will print a single '0' even if r == 0, since we would
169  * immediately jump to out_r where two 0s would be written but only
170  * one of them accounted for in buf. This is needed by ip4_string
171  * below. All other callers pass a non-zero value of r.
172 */
173 static noinline_for_stack
174 char *put_dec_trunc8(char *buf, unsigned r)
175 {
176 	unsigned q;
177 
178 	/* 1 <= r < 10^8 */
179 	if (r < 100)
180 		goto out_r;
181 
182 	/* 100 <= r < 10^8 */
183 	q = (r * (u64)0x28f5c29) >> 32;
184 	*((u16 *)buf) = decpair[r - 100*q];
185 	buf += 2;
186 
187 	/* 1 <= q < 10^6 */
188 	if (q < 100)
189 		goto out_q;
190 
191 	/*  100 <= q < 10^6 */
192 	r = (q * (u64)0x28f5c29) >> 32;
193 	*((u16 *)buf) = decpair[q - 100*r];
194 	buf += 2;
195 
196 	/* 1 <= r < 10^4 */
197 	if (r < 100)
198 		goto out_r;
199 
200 	/* 100 <= r < 10^4 */
201 	q = (r * 0x147b) >> 19;
202 	*((u16 *)buf) = decpair[r - 100*q];
203 	buf += 2;
204 out_q:
205 	/* 1 <= q < 100 */
206 	r = q;
207 out_r:
208 	/* 1 <= r < 100 */
209 	*((u16 *)buf) = decpair[r];
210 	buf += r < 10 ? 1 : 2;
211 	return buf;
212 }
213 
214 #if BITS_PER_LONG == 64 && BITS_PER_LONG_LONG == 64
215 static noinline_for_stack
216 char *put_dec_full8(char *buf, unsigned r)
217 {
218 	unsigned q;
219 
220 	/* 0 <= r < 10^8 */
221 	q = (r * (u64)0x28f5c29) >> 32;
222 	*((u16 *)buf) = decpair[r - 100*q];
223 	buf += 2;
224 
225 	/* 0 <= q < 10^6 */
226 	r = (q * (u64)0x28f5c29) >> 32;
227 	*((u16 *)buf) = decpair[q - 100*r];
228 	buf += 2;
229 
230 	/* 0 <= r < 10^4 */
231 	q = (r * 0x147b) >> 19;
232 	*((u16 *)buf) = decpair[r - 100*q];
233 	buf += 2;
234 
235 	/* 0 <= q < 100 */
236 	*((u16 *)buf) = decpair[q];
237 	buf += 2;
238 	return buf;
239 }
240 
241 static noinline_for_stack
242 char *put_dec(char *buf, unsigned long long n)
243 {
244 	if (n >= 100*1000*1000)
245 		buf = put_dec_full8(buf, do_div(n, 100*1000*1000));
246 	/* 1 <= n <= 1.6e11 */
247 	if (n >= 100*1000*1000)
248 		buf = put_dec_full8(buf, do_div(n, 100*1000*1000));
249 	/* 1 <= n < 1e8 */
250 	return put_dec_trunc8(buf, n);
251 }
252 
253 #elif BITS_PER_LONG == 32 && BITS_PER_LONG_LONG == 64
254 
255 static void
256 put_dec_full4(char *buf, unsigned r)
257 {
258 	unsigned q;
259 
260 	/* 0 <= r < 10^4 */
261 	q = (r * 0x147b) >> 19;
262 	*((u16 *)buf) = decpair[r - 100*q];
263 	buf += 2;
264 	/* 0 <= q < 100 */
265 	*((u16 *)buf) = decpair[q];
266 }
267 
268 /*
269  * Call put_dec_full4 on x % 10000, return x / 10000.
270  * The approximation x/10000 == (x * 0x346DC5D7) >> 43
271  * holds for all x < 1,128,869,999.  The largest value this
272  * helper will ever be asked to convert is 1,125,520,955.
273  * (second call in the put_dec code, assuming n is all-ones).
274  */
275 static noinline_for_stack
276 unsigned put_dec_helper4(char *buf, unsigned x)
277 {
278         uint32_t q = (x * (uint64_t)0x346DC5D7) >> 43;
279 
280         put_dec_full4(buf, x - q * 10000);
281         return q;
282 }
283 
284 /* Based on code by Douglas W. Jones found at
285  * <http://www.cs.uiowa.edu/~jones/bcd/decimal.html#sixtyfour>
286  * (with permission from the author).
287  * Performs no 64-bit division and hence should be fast on 32-bit machines.
288  */
289 static
290 char *put_dec(char *buf, unsigned long long n)
291 {
292 	uint32_t d3, d2, d1, q, h;
293 
294 	if (n < 100*1000*1000)
295 		return put_dec_trunc8(buf, n);
296 
297 	d1  = ((uint32_t)n >> 16); /* implicit "& 0xffff" */
298 	h   = (n >> 32);
299 	d2  = (h      ) & 0xffff;
300 	d3  = (h >> 16); /* implicit "& 0xffff" */
301 
302 	/* n = 2^48 d3 + 2^32 d2 + 2^16 d1 + d0
303 	     = 281_4749_7671_0656 d3 + 42_9496_7296 d2 + 6_5536 d1 + d0 */
304 	q   = 656 * d3 + 7296 * d2 + 5536 * d1 + ((uint32_t)n & 0xffff);
305 	q = put_dec_helper4(buf, q);
306 
307 	q += 7671 * d3 + 9496 * d2 + 6 * d1;
308 	q = put_dec_helper4(buf+4, q);
309 
310 	q += 4749 * d3 + 42 * d2;
311 	q = put_dec_helper4(buf+8, q);
312 
313 	q += 281 * d3;
314 	buf += 12;
315 	if (q)
316 		buf = put_dec_trunc8(buf, q);
317 	else while (buf[-1] == '0')
318 		--buf;
319 
320 	return buf;
321 }
322 
323 #endif
324 
325 /*
326  * Convert passed number to decimal string.
327  * Returns the length of string.  On buffer overflow, returns 0.
328  *
329  * If speed is not important, use snprintf(). It's easy to read the code.
330  */
331 int num_to_str(char *buf, int size, unsigned long long num)
332 {
333 	/* put_dec requires 2-byte alignment of the buffer. */
334 	char tmp[sizeof(num) * 3] __aligned(2);
335 	int idx, len;
336 
337 	/* put_dec() may work incorrectly for num = 0 (generate "", not "0") */
338 	if (num <= 9) {
339 		tmp[0] = '0' + num;
340 		len = 1;
341 	} else {
342 		len = put_dec(tmp, num) - tmp;
343 	}
344 
345 	if (len > size)
346 		return 0;
347 	for (idx = 0; idx < len; ++idx)
348 		buf[idx] = tmp[len - idx - 1];
349 	return len;
350 }
351 
352 #define SIGN	1		/* unsigned/signed, must be 1 */
353 #define LEFT	2		/* left justified */
354 #define PLUS	4		/* show plus */
355 #define SPACE	8		/* space if plus */
356 #define ZEROPAD	16		/* pad with zero, must be 16 == '0' - ' ' */
357 #define SMALL	32		/* use lowercase in hex (must be 32 == 0x20) */
358 #define SPECIAL	64		/* prefix hex with "0x", octal with "0" */
359 
360 enum format_type {
361 	FORMAT_TYPE_NONE, /* Just a string part */
362 	FORMAT_TYPE_WIDTH,
363 	FORMAT_TYPE_PRECISION,
364 	FORMAT_TYPE_CHAR,
365 	FORMAT_TYPE_STR,
366 	FORMAT_TYPE_PTR,
367 	FORMAT_TYPE_PERCENT_CHAR,
368 	FORMAT_TYPE_INVALID,
369 	FORMAT_TYPE_LONG_LONG,
370 	FORMAT_TYPE_ULONG,
371 	FORMAT_TYPE_LONG,
372 	FORMAT_TYPE_UBYTE,
373 	FORMAT_TYPE_BYTE,
374 	FORMAT_TYPE_USHORT,
375 	FORMAT_TYPE_SHORT,
376 	FORMAT_TYPE_UINT,
377 	FORMAT_TYPE_INT,
378 	FORMAT_TYPE_SIZE_T,
379 	FORMAT_TYPE_PTRDIFF
380 };
381 
382 struct printf_spec {
383 	u8	type;		/* format_type enum */
384 	u8	flags;		/* flags to number() */
385 	u8	base;		/* number base, 8, 10 or 16 only */
386 	u8	qualifier;	/* number qualifier, one of 'hHlLtzZ' */
387 	s16	field_width;	/* width of output field */
388 	s16	precision;	/* # of digits/chars */
389 };
390 
391 static noinline_for_stack
392 char *number(char *buf, char *end, unsigned long long num,
393 	     struct printf_spec spec)
394 {
395 	/* put_dec requires 2-byte alignment of the buffer. */
396 	char tmp[3 * sizeof(num)] __aligned(2);
397 	char sign;
398 	char locase;
399 	int need_pfx = ((spec.flags & SPECIAL) && spec.base != 10);
400 	int i;
401 	bool is_zero = num == 0LL;
402 
403 	/* locase = 0 or 0x20. ORing digits or letters with 'locase'
404 	 * produces same digits or (maybe lowercased) letters */
405 	locase = (spec.flags & SMALL);
406 	if (spec.flags & LEFT)
407 		spec.flags &= ~ZEROPAD;
408 	sign = 0;
409 	if (spec.flags & SIGN) {
410 		if ((signed long long)num < 0) {
411 			sign = '-';
412 			num = -(signed long long)num;
413 			spec.field_width--;
414 		} else if (spec.flags & PLUS) {
415 			sign = '+';
416 			spec.field_width--;
417 		} else if (spec.flags & SPACE) {
418 			sign = ' ';
419 			spec.field_width--;
420 		}
421 	}
422 	if (need_pfx) {
423 		if (spec.base == 16)
424 			spec.field_width -= 2;
425 		else if (!is_zero)
426 			spec.field_width--;
427 	}
428 
429 	/* generate full string in tmp[], in reverse order */
430 	i = 0;
431 	if (num < spec.base)
432 		tmp[i++] = hex_asc_upper[num] | locase;
433 	else if (spec.base != 10) { /* 8 or 16 */
434 		int mask = spec.base - 1;
435 		int shift = 3;
436 
437 		if (spec.base == 16)
438 			shift = 4;
439 		do {
440 			tmp[i++] = (hex_asc_upper[((unsigned char)num) & mask] | locase);
441 			num >>= shift;
442 		} while (num);
443 	} else { /* base 10 */
444 		i = put_dec(tmp, num) - tmp;
445 	}
446 
447 	/* printing 100 using %2d gives "100", not "00" */
448 	if (i > spec.precision)
449 		spec.precision = i;
450 	/* leading space padding */
451 	spec.field_width -= spec.precision;
452 	if (!(spec.flags & (ZEROPAD | LEFT))) {
453 		while (--spec.field_width >= 0) {
454 			if (buf < end)
455 				*buf = ' ';
456 			++buf;
457 		}
458 	}
459 	/* sign */
460 	if (sign) {
461 		if (buf < end)
462 			*buf = sign;
463 		++buf;
464 	}
465 	/* "0x" / "0" prefix */
466 	if (need_pfx) {
467 		if (spec.base == 16 || !is_zero) {
468 			if (buf < end)
469 				*buf = '0';
470 			++buf;
471 		}
472 		if (spec.base == 16) {
473 			if (buf < end)
474 				*buf = ('X' | locase);
475 			++buf;
476 		}
477 	}
478 	/* zero or space padding */
479 	if (!(spec.flags & LEFT)) {
480 		char c = ' ' + (spec.flags & ZEROPAD);
481 		BUILD_BUG_ON(' ' + ZEROPAD != '0');
482 		while (--spec.field_width >= 0) {
483 			if (buf < end)
484 				*buf = c;
485 			++buf;
486 		}
487 	}
488 	/* hmm even more zero padding? */
489 	while (i <= --spec.precision) {
490 		if (buf < end)
491 			*buf = '0';
492 		++buf;
493 	}
494 	/* actual digits of result */
495 	while (--i >= 0) {
496 		if (buf < end)
497 			*buf = tmp[i];
498 		++buf;
499 	}
500 	/* trailing space padding */
501 	while (--spec.field_width >= 0) {
502 		if (buf < end)
503 			*buf = ' ';
504 		++buf;
505 	}
506 
507 	return buf;
508 }
509 
510 static noinline_for_stack
511 char *string(char *buf, char *end, const char *s, struct printf_spec spec)
512 {
513 	int len, i;
514 
515 	if ((unsigned long)s < PAGE_SIZE)
516 		s = "(null)";
517 
518 	len = strnlen(s, spec.precision);
519 
520 	if (!(spec.flags & LEFT)) {
521 		while (len < spec.field_width--) {
522 			if (buf < end)
523 				*buf = ' ';
524 			++buf;
525 		}
526 	}
527 	for (i = 0; i < len; ++i) {
528 		if (buf < end)
529 			*buf = *s;
530 		++buf; ++s;
531 	}
532 	while (len < spec.field_width--) {
533 		if (buf < end)
534 			*buf = ' ';
535 		++buf;
536 	}
537 
538 	return buf;
539 }
540 
541 static void widen(char *buf, char *end, unsigned len, unsigned spaces)
542 {
543 	size_t size;
544 	if (buf >= end)	/* nowhere to put anything */
545 		return;
546 	size = end - buf;
547 	if (size <= spaces) {
548 		memset(buf, ' ', size);
549 		return;
550 	}
551 	if (len) {
552 		if (len > size - spaces)
553 			len = size - spaces;
554 		memmove(buf + spaces, buf, len);
555 	}
556 	memset(buf, ' ', spaces);
557 }
558 
559 static noinline_for_stack
560 char *dentry_name(char *buf, char *end, const struct dentry *d, struct printf_spec spec,
561 		  const char *fmt)
562 {
563 	const char *array[4], *s;
564 	const struct dentry *p;
565 	int depth;
566 	int i, n;
567 
568 	switch (fmt[1]) {
569 		case '2': case '3': case '4':
570 			depth = fmt[1] - '0';
571 			break;
572 		default:
573 			depth = 1;
574 	}
575 
576 	rcu_read_lock();
577 	for (i = 0; i < depth; i++, d = p) {
578 		p = ACCESS_ONCE(d->d_parent);
579 		array[i] = ACCESS_ONCE(d->d_name.name);
580 		if (p == d) {
581 			if (i)
582 				array[i] = "";
583 			i++;
584 			break;
585 		}
586 	}
587 	s = array[--i];
588 	for (n = 0; n != spec.precision; n++, buf++) {
589 		char c = *s++;
590 		if (!c) {
591 			if (!i)
592 				break;
593 			c = '/';
594 			s = array[--i];
595 		}
596 		if (buf < end)
597 			*buf = c;
598 	}
599 	rcu_read_unlock();
600 	if (n < spec.field_width) {
601 		/* we want to pad the sucker */
602 		unsigned spaces = spec.field_width - n;
603 		if (!(spec.flags & LEFT)) {
604 			widen(buf - n, end, n, spaces);
605 			return buf + spaces;
606 		}
607 		while (spaces--) {
608 			if (buf < end)
609 				*buf = ' ';
610 			++buf;
611 		}
612 	}
613 	return buf;
614 }
615 
616 static noinline_for_stack
617 char *symbol_string(char *buf, char *end, void *ptr,
618 		    struct printf_spec spec, const char *fmt)
619 {
620 	unsigned long value;
621 #ifdef CONFIG_KALLSYMS
622 	char sym[KSYM_SYMBOL_LEN];
623 #endif
624 
625 	if (fmt[1] == 'R')
626 		ptr = __builtin_extract_return_addr(ptr);
627 	value = (unsigned long)ptr;
628 
629 #ifdef CONFIG_KALLSYMS
630 	if (*fmt == 'B')
631 		sprint_backtrace(sym, value);
632 	else if (*fmt != 'f' && *fmt != 's')
633 		sprint_symbol(sym, value);
634 	else
635 		sprint_symbol_no_offset(sym, value);
636 
637 	return string(buf, end, sym, spec);
638 #else
639 	spec.field_width = 2 * sizeof(void *);
640 	spec.flags |= SPECIAL | SMALL | ZEROPAD;
641 	spec.base = 16;
642 
643 	return number(buf, end, value, spec);
644 #endif
645 }
646 
647 static noinline_for_stack
648 char *resource_string(char *buf, char *end, struct resource *res,
649 		      struct printf_spec spec, const char *fmt)
650 {
651 #ifndef IO_RSRC_PRINTK_SIZE
652 #define IO_RSRC_PRINTK_SIZE	6
653 #endif
654 
655 #ifndef MEM_RSRC_PRINTK_SIZE
656 #define MEM_RSRC_PRINTK_SIZE	10
657 #endif
658 	static const struct printf_spec io_spec = {
659 		.base = 16,
660 		.field_width = IO_RSRC_PRINTK_SIZE,
661 		.precision = -1,
662 		.flags = SPECIAL | SMALL | ZEROPAD,
663 	};
664 	static const struct printf_spec mem_spec = {
665 		.base = 16,
666 		.field_width = MEM_RSRC_PRINTK_SIZE,
667 		.precision = -1,
668 		.flags = SPECIAL | SMALL | ZEROPAD,
669 	};
670 	static const struct printf_spec bus_spec = {
671 		.base = 16,
672 		.field_width = 2,
673 		.precision = -1,
674 		.flags = SMALL | ZEROPAD,
675 	};
676 	static const struct printf_spec dec_spec = {
677 		.base = 10,
678 		.precision = -1,
679 		.flags = 0,
680 	};
681 	static const struct printf_spec str_spec = {
682 		.field_width = -1,
683 		.precision = 10,
684 		.flags = LEFT,
685 	};
686 	static const struct printf_spec flag_spec = {
687 		.base = 16,
688 		.precision = -1,
689 		.flags = SPECIAL | SMALL,
690 	};
691 
692 	/* 32-bit res (sizeof==4): 10 chars in dec, 10 in hex ("0x" + 8)
693 	 * 64-bit res (sizeof==8): 20 chars in dec, 18 in hex ("0x" + 16) */
694 #define RSRC_BUF_SIZE		((2 * sizeof(resource_size_t)) + 4)
695 #define FLAG_BUF_SIZE		(2 * sizeof(res->flags))
696 #define DECODED_BUF_SIZE	sizeof("[mem - 64bit pref window disabled]")
697 #define RAW_BUF_SIZE		sizeof("[mem - flags 0x]")
698 	char sym[max(2*RSRC_BUF_SIZE + DECODED_BUF_SIZE,
699 		     2*RSRC_BUF_SIZE + FLAG_BUF_SIZE + RAW_BUF_SIZE)];
700 
701 	char *p = sym, *pend = sym + sizeof(sym);
702 	int decode = (fmt[0] == 'R') ? 1 : 0;
703 	const struct printf_spec *specp;
704 
705 	*p++ = '[';
706 	if (res->flags & IORESOURCE_IO) {
707 		p = string(p, pend, "io  ", str_spec);
708 		specp = &io_spec;
709 	} else if (res->flags & IORESOURCE_MEM) {
710 		p = string(p, pend, "mem ", str_spec);
711 		specp = &mem_spec;
712 	} else if (res->flags & IORESOURCE_IRQ) {
713 		p = string(p, pend, "irq ", str_spec);
714 		specp = &dec_spec;
715 	} else if (res->flags & IORESOURCE_DMA) {
716 		p = string(p, pend, "dma ", str_spec);
717 		specp = &dec_spec;
718 	} else if (res->flags & IORESOURCE_BUS) {
719 		p = string(p, pend, "bus ", str_spec);
720 		specp = &bus_spec;
721 	} else {
722 		p = string(p, pend, "??? ", str_spec);
723 		specp = &mem_spec;
724 		decode = 0;
725 	}
726 	if (decode && res->flags & IORESOURCE_UNSET) {
727 		p = string(p, pend, "size ", str_spec);
728 		p = number(p, pend, resource_size(res), *specp);
729 	} else {
730 		p = number(p, pend, res->start, *specp);
731 		if (res->start != res->end) {
732 			*p++ = '-';
733 			p = number(p, pend, res->end, *specp);
734 		}
735 	}
736 	if (decode) {
737 		if (res->flags & IORESOURCE_MEM_64)
738 			p = string(p, pend, " 64bit", str_spec);
739 		if (res->flags & IORESOURCE_PREFETCH)
740 			p = string(p, pend, " pref", str_spec);
741 		if (res->flags & IORESOURCE_WINDOW)
742 			p = string(p, pend, " window", str_spec);
743 		if (res->flags & IORESOURCE_DISABLED)
744 			p = string(p, pend, " disabled", str_spec);
745 	} else {
746 		p = string(p, pend, " flags ", str_spec);
747 		p = number(p, pend, res->flags, flag_spec);
748 	}
749 	*p++ = ']';
750 	*p = '\0';
751 
752 	return string(buf, end, sym, spec);
753 }
754 
755 static noinline_for_stack
756 char *hex_string(char *buf, char *end, u8 *addr, struct printf_spec spec,
757 		 const char *fmt)
758 {
759 	int i, len = 1;		/* if we pass '%ph[CDN]', field width remains
760 				   negative value, fallback to the default */
761 	char separator;
762 
763 	if (spec.field_width == 0)
764 		/* nothing to print */
765 		return buf;
766 
767 	if (ZERO_OR_NULL_PTR(addr))
768 		/* NULL pointer */
769 		return string(buf, end, NULL, spec);
770 
771 	switch (fmt[1]) {
772 	case 'C':
773 		separator = ':';
774 		break;
775 	case 'D':
776 		separator = '-';
777 		break;
778 	case 'N':
779 		separator = 0;
780 		break;
781 	default:
782 		separator = ' ';
783 		break;
784 	}
785 
786 	if (spec.field_width > 0)
787 		len = min_t(int, spec.field_width, 64);
788 
789 	for (i = 0; i < len; ++i) {
790 		if (buf < end)
791 			*buf = hex_asc_hi(addr[i]);
792 		++buf;
793 		if (buf < end)
794 			*buf = hex_asc_lo(addr[i]);
795 		++buf;
796 
797 		if (separator && i != len - 1) {
798 			if (buf < end)
799 				*buf = separator;
800 			++buf;
801 		}
802 	}
803 
804 	return buf;
805 }
806 
807 static noinline_for_stack
808 char *bitmap_string(char *buf, char *end, unsigned long *bitmap,
809 		    struct printf_spec spec, const char *fmt)
810 {
811 	const int CHUNKSZ = 32;
812 	int nr_bits = max_t(int, spec.field_width, 0);
813 	int i, chunksz;
814 	bool first = true;
815 
816 	/* reused to print numbers */
817 	spec = (struct printf_spec){ .flags = SMALL | ZEROPAD, .base = 16 };
818 
819 	chunksz = nr_bits & (CHUNKSZ - 1);
820 	if (chunksz == 0)
821 		chunksz = CHUNKSZ;
822 
823 	i = ALIGN(nr_bits, CHUNKSZ) - CHUNKSZ;
824 	for (; i >= 0; i -= CHUNKSZ) {
825 		u32 chunkmask, val;
826 		int word, bit;
827 
828 		chunkmask = ((1ULL << chunksz) - 1);
829 		word = i / BITS_PER_LONG;
830 		bit = i % BITS_PER_LONG;
831 		val = (bitmap[word] >> bit) & chunkmask;
832 
833 		if (!first) {
834 			if (buf < end)
835 				*buf = ',';
836 			buf++;
837 		}
838 		first = false;
839 
840 		spec.field_width = DIV_ROUND_UP(chunksz, 4);
841 		buf = number(buf, end, val, spec);
842 
843 		chunksz = CHUNKSZ;
844 	}
845 	return buf;
846 }
847 
848 static noinline_for_stack
849 char *bitmap_list_string(char *buf, char *end, unsigned long *bitmap,
850 			 struct printf_spec spec, const char *fmt)
851 {
852 	int nr_bits = max_t(int, spec.field_width, 0);
853 	/* current bit is 'cur', most recently seen range is [rbot, rtop] */
854 	int cur, rbot, rtop;
855 	bool first = true;
856 
857 	/* reused to print numbers */
858 	spec = (struct printf_spec){ .base = 10 };
859 
860 	rbot = cur = find_first_bit(bitmap, nr_bits);
861 	while (cur < nr_bits) {
862 		rtop = cur;
863 		cur = find_next_bit(bitmap, nr_bits, cur + 1);
864 		if (cur < nr_bits && cur <= rtop + 1)
865 			continue;
866 
867 		if (!first) {
868 			if (buf < end)
869 				*buf = ',';
870 			buf++;
871 		}
872 		first = false;
873 
874 		buf = number(buf, end, rbot, spec);
875 		if (rbot < rtop) {
876 			if (buf < end)
877 				*buf = '-';
878 			buf++;
879 
880 			buf = number(buf, end, rtop, spec);
881 		}
882 
883 		rbot = cur;
884 	}
885 	return buf;
886 }
887 
888 static noinline_for_stack
889 char *mac_address_string(char *buf, char *end, u8 *addr,
890 			 struct printf_spec spec, const char *fmt)
891 {
892 	char mac_addr[sizeof("xx:xx:xx:xx:xx:xx")];
893 	char *p = mac_addr;
894 	int i;
895 	char separator;
896 	bool reversed = false;
897 
898 	switch (fmt[1]) {
899 	case 'F':
900 		separator = '-';
901 		break;
902 
903 	case 'R':
904 		reversed = true;
905 		/* fall through */
906 
907 	default:
908 		separator = ':';
909 		break;
910 	}
911 
912 	for (i = 0; i < 6; i++) {
913 		if (reversed)
914 			p = hex_byte_pack(p, addr[5 - i]);
915 		else
916 			p = hex_byte_pack(p, addr[i]);
917 
918 		if (fmt[0] == 'M' && i != 5)
919 			*p++ = separator;
920 	}
921 	*p = '\0';
922 
923 	return string(buf, end, mac_addr, spec);
924 }
925 
926 static noinline_for_stack
927 char *ip4_string(char *p, const u8 *addr, const char *fmt)
928 {
929 	int i;
930 	bool leading_zeros = (fmt[0] == 'i');
931 	int index;
932 	int step;
933 
934 	switch (fmt[2]) {
935 	case 'h':
936 #ifdef __BIG_ENDIAN
937 		index = 0;
938 		step = 1;
939 #else
940 		index = 3;
941 		step = -1;
942 #endif
943 		break;
944 	case 'l':
945 		index = 3;
946 		step = -1;
947 		break;
948 	case 'n':
949 	case 'b':
950 	default:
951 		index = 0;
952 		step = 1;
953 		break;
954 	}
955 	for (i = 0; i < 4; i++) {
956 		char temp[4] __aligned(2);	/* hold each IP quad in reverse order */
957 		int digits = put_dec_trunc8(temp, addr[index]) - temp;
958 		if (leading_zeros) {
959 			if (digits < 3)
960 				*p++ = '0';
961 			if (digits < 2)
962 				*p++ = '0';
963 		}
964 		/* reverse the digits in the quad */
965 		while (digits--)
966 			*p++ = temp[digits];
967 		if (i < 3)
968 			*p++ = '.';
969 		index += step;
970 	}
971 	*p = '\0';
972 
973 	return p;
974 }
975 
976 static noinline_for_stack
977 char *ip6_compressed_string(char *p, const char *addr)
978 {
979 	int i, j, range;
980 	unsigned char zerolength[8];
981 	int longest = 1;
982 	int colonpos = -1;
983 	u16 word;
984 	u8 hi, lo;
985 	bool needcolon = false;
986 	bool useIPv4;
987 	struct in6_addr in6;
988 
989 	memcpy(&in6, addr, sizeof(struct in6_addr));
990 
991 	useIPv4 = ipv6_addr_v4mapped(&in6) || ipv6_addr_is_isatap(&in6);
992 
993 	memset(zerolength, 0, sizeof(zerolength));
994 
995 	if (useIPv4)
996 		range = 6;
997 	else
998 		range = 8;
999 
1000 	/* find position of longest 0 run */
1001 	for (i = 0; i < range; i++) {
1002 		for (j = i; j < range; j++) {
1003 			if (in6.s6_addr16[j] != 0)
1004 				break;
1005 			zerolength[i]++;
1006 		}
1007 	}
1008 	for (i = 0; i < range; i++) {
1009 		if (zerolength[i] > longest) {
1010 			longest = zerolength[i];
1011 			colonpos = i;
1012 		}
1013 	}
1014 	if (longest == 1)		/* don't compress a single 0 */
1015 		colonpos = -1;
1016 
1017 	/* emit address */
1018 	for (i = 0; i < range; i++) {
1019 		if (i == colonpos) {
1020 			if (needcolon || i == 0)
1021 				*p++ = ':';
1022 			*p++ = ':';
1023 			needcolon = false;
1024 			i += longest - 1;
1025 			continue;
1026 		}
1027 		if (needcolon) {
1028 			*p++ = ':';
1029 			needcolon = false;
1030 		}
1031 		/* hex u16 without leading 0s */
1032 		word = ntohs(in6.s6_addr16[i]);
1033 		hi = word >> 8;
1034 		lo = word & 0xff;
1035 		if (hi) {
1036 			if (hi > 0x0f)
1037 				p = hex_byte_pack(p, hi);
1038 			else
1039 				*p++ = hex_asc_lo(hi);
1040 			p = hex_byte_pack(p, lo);
1041 		}
1042 		else if (lo > 0x0f)
1043 			p = hex_byte_pack(p, lo);
1044 		else
1045 			*p++ = hex_asc_lo(lo);
1046 		needcolon = true;
1047 	}
1048 
1049 	if (useIPv4) {
1050 		if (needcolon)
1051 			*p++ = ':';
1052 		p = ip4_string(p, &in6.s6_addr[12], "I4");
1053 	}
1054 	*p = '\0';
1055 
1056 	return p;
1057 }
1058 
1059 static noinline_for_stack
1060 char *ip6_string(char *p, const char *addr, const char *fmt)
1061 {
1062 	int i;
1063 
1064 	for (i = 0; i < 8; i++) {
1065 		p = hex_byte_pack(p, *addr++);
1066 		p = hex_byte_pack(p, *addr++);
1067 		if (fmt[0] == 'I' && i != 7)
1068 			*p++ = ':';
1069 	}
1070 	*p = '\0';
1071 
1072 	return p;
1073 }
1074 
1075 static noinline_for_stack
1076 char *ip6_addr_string(char *buf, char *end, const u8 *addr,
1077 		      struct printf_spec spec, const char *fmt)
1078 {
1079 	char ip6_addr[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255")];
1080 
1081 	if (fmt[0] == 'I' && fmt[2] == 'c')
1082 		ip6_compressed_string(ip6_addr, addr);
1083 	else
1084 		ip6_string(ip6_addr, addr, fmt);
1085 
1086 	return string(buf, end, ip6_addr, spec);
1087 }
1088 
1089 static noinline_for_stack
1090 char *ip4_addr_string(char *buf, char *end, const u8 *addr,
1091 		      struct printf_spec spec, const char *fmt)
1092 {
1093 	char ip4_addr[sizeof("255.255.255.255")];
1094 
1095 	ip4_string(ip4_addr, addr, fmt);
1096 
1097 	return string(buf, end, ip4_addr, spec);
1098 }
1099 
1100 static noinline_for_stack
1101 char *ip6_addr_string_sa(char *buf, char *end, const struct sockaddr_in6 *sa,
1102 			 struct printf_spec spec, const char *fmt)
1103 {
1104 	bool have_p = false, have_s = false, have_f = false, have_c = false;
1105 	char ip6_addr[sizeof("[xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255]") +
1106 		      sizeof(":12345") + sizeof("/123456789") +
1107 		      sizeof("%1234567890")];
1108 	char *p = ip6_addr, *pend = ip6_addr + sizeof(ip6_addr);
1109 	const u8 *addr = (const u8 *) &sa->sin6_addr;
1110 	char fmt6[2] = { fmt[0], '6' };
1111 	u8 off = 0;
1112 
1113 	fmt++;
1114 	while (isalpha(*++fmt)) {
1115 		switch (*fmt) {
1116 		case 'p':
1117 			have_p = true;
1118 			break;
1119 		case 'f':
1120 			have_f = true;
1121 			break;
1122 		case 's':
1123 			have_s = true;
1124 			break;
1125 		case 'c':
1126 			have_c = true;
1127 			break;
1128 		}
1129 	}
1130 
1131 	if (have_p || have_s || have_f) {
1132 		*p = '[';
1133 		off = 1;
1134 	}
1135 
1136 	if (fmt6[0] == 'I' && have_c)
1137 		p = ip6_compressed_string(ip6_addr + off, addr);
1138 	else
1139 		p = ip6_string(ip6_addr + off, addr, fmt6);
1140 
1141 	if (have_p || have_s || have_f)
1142 		*p++ = ']';
1143 
1144 	if (have_p) {
1145 		*p++ = ':';
1146 		p = number(p, pend, ntohs(sa->sin6_port), spec);
1147 	}
1148 	if (have_f) {
1149 		*p++ = '/';
1150 		p = number(p, pend, ntohl(sa->sin6_flowinfo &
1151 					  IPV6_FLOWINFO_MASK), spec);
1152 	}
1153 	if (have_s) {
1154 		*p++ = '%';
1155 		p = number(p, pend, sa->sin6_scope_id, spec);
1156 	}
1157 	*p = '\0';
1158 
1159 	return string(buf, end, ip6_addr, spec);
1160 }
1161 
1162 static noinline_for_stack
1163 char *ip4_addr_string_sa(char *buf, char *end, const struct sockaddr_in *sa,
1164 			 struct printf_spec spec, const char *fmt)
1165 {
1166 	bool have_p = false;
1167 	char *p, ip4_addr[sizeof("255.255.255.255") + sizeof(":12345")];
1168 	char *pend = ip4_addr + sizeof(ip4_addr);
1169 	const u8 *addr = (const u8 *) &sa->sin_addr.s_addr;
1170 	char fmt4[3] = { fmt[0], '4', 0 };
1171 
1172 	fmt++;
1173 	while (isalpha(*++fmt)) {
1174 		switch (*fmt) {
1175 		case 'p':
1176 			have_p = true;
1177 			break;
1178 		case 'h':
1179 		case 'l':
1180 		case 'n':
1181 		case 'b':
1182 			fmt4[2] = *fmt;
1183 			break;
1184 		}
1185 	}
1186 
1187 	p = ip4_string(ip4_addr, addr, fmt4);
1188 	if (have_p) {
1189 		*p++ = ':';
1190 		p = number(p, pend, ntohs(sa->sin_port), spec);
1191 	}
1192 	*p = '\0';
1193 
1194 	return string(buf, end, ip4_addr, spec);
1195 }
1196 
1197 static noinline_for_stack
1198 char *escaped_string(char *buf, char *end, u8 *addr, struct printf_spec spec,
1199 		     const char *fmt)
1200 {
1201 	bool found = true;
1202 	int count = 1;
1203 	unsigned int flags = 0;
1204 	int len;
1205 
1206 	if (spec.field_width == 0)
1207 		return buf;				/* nothing to print */
1208 
1209 	if (ZERO_OR_NULL_PTR(addr))
1210 		return string(buf, end, NULL, spec);	/* NULL pointer */
1211 
1212 
1213 	do {
1214 		switch (fmt[count++]) {
1215 		case 'a':
1216 			flags |= ESCAPE_ANY;
1217 			break;
1218 		case 'c':
1219 			flags |= ESCAPE_SPECIAL;
1220 			break;
1221 		case 'h':
1222 			flags |= ESCAPE_HEX;
1223 			break;
1224 		case 'n':
1225 			flags |= ESCAPE_NULL;
1226 			break;
1227 		case 'o':
1228 			flags |= ESCAPE_OCTAL;
1229 			break;
1230 		case 'p':
1231 			flags |= ESCAPE_NP;
1232 			break;
1233 		case 's':
1234 			flags |= ESCAPE_SPACE;
1235 			break;
1236 		default:
1237 			found = false;
1238 			break;
1239 		}
1240 	} while (found);
1241 
1242 	if (!flags)
1243 		flags = ESCAPE_ANY_NP;
1244 
1245 	len = spec.field_width < 0 ? 1 : spec.field_width;
1246 
1247 	/*
1248 	 * string_escape_mem() writes as many characters as it can to
1249 	 * the given buffer, and returns the total size of the output
1250 	 * had the buffer been big enough.
1251 	 */
1252 	buf += string_escape_mem(addr, len, buf, buf < end ? end - buf : 0, flags, NULL);
1253 
1254 	return buf;
1255 }
1256 
1257 static noinline_for_stack
1258 char *uuid_string(char *buf, char *end, const u8 *addr,
1259 		  struct printf_spec spec, const char *fmt)
1260 {
1261 	char uuid[sizeof("xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx")];
1262 	char *p = uuid;
1263 	int i;
1264 	static const u8 be[16] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
1265 	static const u8 le[16] = {3,2,1,0,5,4,7,6,8,9,10,11,12,13,14,15};
1266 	const u8 *index = be;
1267 	bool uc = false;
1268 
1269 	switch (*(++fmt)) {
1270 	case 'L':
1271 		uc = true;		/* fall-through */
1272 	case 'l':
1273 		index = le;
1274 		break;
1275 	case 'B':
1276 		uc = true;
1277 		break;
1278 	}
1279 
1280 	for (i = 0; i < 16; i++) {
1281 		p = hex_byte_pack(p, addr[index[i]]);
1282 		switch (i) {
1283 		case 3:
1284 		case 5:
1285 		case 7:
1286 		case 9:
1287 			*p++ = '-';
1288 			break;
1289 		}
1290 	}
1291 
1292 	*p = 0;
1293 
1294 	if (uc) {
1295 		p = uuid;
1296 		do {
1297 			*p = toupper(*p);
1298 		} while (*(++p));
1299 	}
1300 
1301 	return string(buf, end, uuid, spec);
1302 }
1303 
1304 static
1305 char *netdev_feature_string(char *buf, char *end, const u8 *addr,
1306 		      struct printf_spec spec)
1307 {
1308 	spec.flags |= SPECIAL | SMALL | ZEROPAD;
1309 	if (spec.field_width == -1)
1310 		spec.field_width = 2 + 2 * sizeof(netdev_features_t);
1311 	spec.base = 16;
1312 
1313 	return number(buf, end, *(const netdev_features_t *)addr, spec);
1314 }
1315 
1316 static noinline_for_stack
1317 char *address_val(char *buf, char *end, const void *addr,
1318 		  struct printf_spec spec, const char *fmt)
1319 {
1320 	unsigned long long num;
1321 
1322 	spec.flags |= SPECIAL | SMALL | ZEROPAD;
1323 	spec.base = 16;
1324 
1325 	switch (fmt[1]) {
1326 	case 'd':
1327 		num = *(const dma_addr_t *)addr;
1328 		spec.field_width = sizeof(dma_addr_t) * 2 + 2;
1329 		break;
1330 	case 'p':
1331 	default:
1332 		num = *(const phys_addr_t *)addr;
1333 		spec.field_width = sizeof(phys_addr_t) * 2 + 2;
1334 		break;
1335 	}
1336 
1337 	return number(buf, end, num, spec);
1338 }
1339 
1340 static noinline_for_stack
1341 char *clock(char *buf, char *end, struct clk *clk, struct printf_spec spec,
1342 	    const char *fmt)
1343 {
1344 	if (!IS_ENABLED(CONFIG_HAVE_CLK) || !clk)
1345 		return string(buf, end, NULL, spec);
1346 
1347 	switch (fmt[1]) {
1348 	case 'r':
1349 		return number(buf, end, clk_get_rate(clk), spec);
1350 
1351 	case 'n':
1352 	default:
1353 #ifdef CONFIG_COMMON_CLK
1354 		return string(buf, end, __clk_get_name(clk), spec);
1355 #else
1356 		spec.base = 16;
1357 		spec.field_width = sizeof(unsigned long) * 2 + 2;
1358 		spec.flags |= SPECIAL | SMALL | ZEROPAD;
1359 		return number(buf, end, (unsigned long)clk, spec);
1360 #endif
1361 	}
1362 }
1363 
1364 int kptr_restrict __read_mostly;
1365 
1366 /*
1367  * Show a '%p' thing.  A kernel extension is that the '%p' is followed
1368  * by an extra set of alphanumeric characters that are extended format
1369  * specifiers.
1370  *
1371  * Right now we handle:
1372  *
1373  * - 'F' For symbolic function descriptor pointers with offset
1374  * - 'f' For simple symbolic function names without offset
1375  * - 'S' For symbolic direct pointers with offset
1376  * - 's' For symbolic direct pointers without offset
1377  * - '[FfSs]R' as above with __builtin_extract_return_addr() translation
1378  * - 'B' For backtraced symbolic direct pointers with offset
1379  * - 'R' For decoded struct resource, e.g., [mem 0x0-0x1f 64bit pref]
1380  * - 'r' For raw struct resource, e.g., [mem 0x0-0x1f flags 0x201]
1381  * - 'b[l]' For a bitmap, the number of bits is determined by the field
1382  *       width which must be explicitly specified either as part of the
1383  *       format string '%32b[l]' or through '%*b[l]', [l] selects
1384  *       range-list format instead of hex format
1385  * - 'M' For a 6-byte MAC address, it prints the address in the
1386  *       usual colon-separated hex notation
1387  * - 'm' For a 6-byte MAC address, it prints the hex address without colons
1388  * - 'MF' For a 6-byte MAC FDDI address, it prints the address
1389  *       with a dash-separated hex notation
1390  * - '[mM]R' For a 6-byte MAC address, Reverse order (Bluetooth)
1391  * - 'I' [46] for IPv4/IPv6 addresses printed in the usual way
1392  *       IPv4 uses dot-separated decimal without leading 0's (1.2.3.4)
1393  *       IPv6 uses colon separated network-order 16 bit hex with leading 0's
1394  *       [S][pfs]
1395  *       Generic IPv4/IPv6 address (struct sockaddr *) that falls back to
1396  *       [4] or [6] and is able to print port [p], flowinfo [f], scope [s]
1397  * - 'i' [46] for 'raw' IPv4/IPv6 addresses
1398  *       IPv6 omits the colons (01020304...0f)
1399  *       IPv4 uses dot-separated decimal with leading 0's (010.123.045.006)
1400  *       [S][pfs]
1401  *       Generic IPv4/IPv6 address (struct sockaddr *) that falls back to
1402  *       [4] or [6] and is able to print port [p], flowinfo [f], scope [s]
1403  * - '[Ii][4S][hnbl]' IPv4 addresses in host, network, big or little endian order
1404  * - 'I[6S]c' for IPv6 addresses printed as specified by
1405  *       http://tools.ietf.org/html/rfc5952
1406  * - 'E[achnops]' For an escaped buffer, where rules are defined by combination
1407  *                of the following flags (see string_escape_mem() for the
1408  *                details):
1409  *                  a - ESCAPE_ANY
1410  *                  c - ESCAPE_SPECIAL
1411  *                  h - ESCAPE_HEX
1412  *                  n - ESCAPE_NULL
1413  *                  o - ESCAPE_OCTAL
1414  *                  p - ESCAPE_NP
1415  *                  s - ESCAPE_SPACE
1416  *                By default ESCAPE_ANY_NP is used.
1417  * - 'U' For a 16 byte UUID/GUID, it prints the UUID/GUID in the form
1418  *       "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
1419  *       Options for %pU are:
1420  *         b big endian lower case hex (default)
1421  *         B big endian UPPER case hex
1422  *         l little endian lower case hex
1423  *         L little endian UPPER case hex
1424  *           big endian output byte order is:
1425  *             [0][1][2][3]-[4][5]-[6][7]-[8][9]-[10][11][12][13][14][15]
1426  *           little endian output byte order is:
1427  *             [3][2][1][0]-[5][4]-[7][6]-[8][9]-[10][11][12][13][14][15]
1428  * - 'V' For a struct va_format which contains a format string * and va_list *,
1429  *       call vsnprintf(->format, *->va_list).
1430  *       Implements a "recursive vsnprintf".
1431  *       Do not use this feature without some mechanism to verify the
1432  *       correctness of the format string and va_list arguments.
1433  * - 'K' For a kernel pointer that should be hidden from unprivileged users
1434  * - 'NF' For a netdev_features_t
1435  * - 'h[CDN]' For a variable-length buffer, it prints it as a hex string with
1436  *            a certain separator (' ' by default):
1437  *              C colon
1438  *              D dash
1439  *              N no separator
1440  *            The maximum supported length is 64 bytes of the input. Consider
1441  *            to use print_hex_dump() for the larger input.
1442  * - 'a[pd]' For address types [p] phys_addr_t, [d] dma_addr_t and derivatives
1443  *           (default assumed to be phys_addr_t, passed by reference)
1444  * - 'd[234]' For a dentry name (optionally 2-4 last components)
1445  * - 'D[234]' Same as 'd' but for a struct file
1446  * - 'C' For a clock, it prints the name (Common Clock Framework) or address
1447  *       (legacy clock framework) of the clock
1448  * - 'Cn' For a clock, it prints the name (Common Clock Framework) or address
1449  *        (legacy clock framework) of the clock
1450  * - 'Cr' For a clock, it prints the current rate of the clock
1451  *
1452  * ** Please update also Documentation/printk-formats.txt when making changes **
1453  *
1454  * Note: The difference between 'S' and 'F' is that on ia64 and ppc64
1455  * function pointers are really function descriptors, which contain a
1456  * pointer to the real address.
1457  */
1458 static noinline_for_stack
1459 char *pointer(const char *fmt, char *buf, char *end, void *ptr,
1460 	      struct printf_spec spec)
1461 {
1462 	const int default_width = 2 * sizeof(void *);
1463 
1464 	if (!ptr && *fmt != 'K') {
1465 		/*
1466 		 * Print (null) with the same width as a pointer so it makes
1467 		 * tabular output look nice.
1468 		 */
1469 		if (spec.field_width == -1)
1470 			spec.field_width = default_width;
1471 		return string(buf, end, "(null)", spec);
1472 	}
1473 
1474 	switch (*fmt) {
1475 	case 'F':
1476 	case 'f':
1477 		ptr = dereference_function_descriptor(ptr);
1478 		/* Fallthrough */
1479 	case 'S':
1480 	case 's':
1481 	case 'B':
1482 		return symbol_string(buf, end, ptr, spec, fmt);
1483 	case 'R':
1484 	case 'r':
1485 		return resource_string(buf, end, ptr, spec, fmt);
1486 	case 'h':
1487 		return hex_string(buf, end, ptr, spec, fmt);
1488 	case 'b':
1489 		switch (fmt[1]) {
1490 		case 'l':
1491 			return bitmap_list_string(buf, end, ptr, spec, fmt);
1492 		default:
1493 			return bitmap_string(buf, end, ptr, spec, fmt);
1494 		}
1495 	case 'M':			/* Colon separated: 00:01:02:03:04:05 */
1496 	case 'm':			/* Contiguous: 000102030405 */
1497 					/* [mM]F (FDDI) */
1498 					/* [mM]R (Reverse order; Bluetooth) */
1499 		return mac_address_string(buf, end, ptr, spec, fmt);
1500 	case 'I':			/* Formatted IP supported
1501 					 * 4:	1.2.3.4
1502 					 * 6:	0001:0203:...:0708
1503 					 * 6c:	1::708 or 1::1.2.3.4
1504 					 */
1505 	case 'i':			/* Contiguous:
1506 					 * 4:	001.002.003.004
1507 					 * 6:   000102...0f
1508 					 */
1509 		switch (fmt[1]) {
1510 		case '6':
1511 			return ip6_addr_string(buf, end, ptr, spec, fmt);
1512 		case '4':
1513 			return ip4_addr_string(buf, end, ptr, spec, fmt);
1514 		case 'S': {
1515 			const union {
1516 				struct sockaddr		raw;
1517 				struct sockaddr_in	v4;
1518 				struct sockaddr_in6	v6;
1519 			} *sa = ptr;
1520 
1521 			switch (sa->raw.sa_family) {
1522 			case AF_INET:
1523 				return ip4_addr_string_sa(buf, end, &sa->v4, spec, fmt);
1524 			case AF_INET6:
1525 				return ip6_addr_string_sa(buf, end, &sa->v6, spec, fmt);
1526 			default:
1527 				return string(buf, end, "(invalid address)", spec);
1528 			}}
1529 		}
1530 		break;
1531 	case 'E':
1532 		return escaped_string(buf, end, ptr, spec, fmt);
1533 	case 'U':
1534 		return uuid_string(buf, end, ptr, spec, fmt);
1535 	case 'V':
1536 		{
1537 			va_list va;
1538 
1539 			va_copy(va, *((struct va_format *)ptr)->va);
1540 			buf += vsnprintf(buf, end > buf ? end - buf : 0,
1541 					 ((struct va_format *)ptr)->fmt, va);
1542 			va_end(va);
1543 			return buf;
1544 		}
1545 	case 'K':
1546 		/*
1547 		 * %pK cannot be used in IRQ context because its test
1548 		 * for CAP_SYSLOG would be meaningless.
1549 		 */
1550 		if (kptr_restrict && (in_irq() || in_serving_softirq() ||
1551 				      in_nmi())) {
1552 			if (spec.field_width == -1)
1553 				spec.field_width = default_width;
1554 			return string(buf, end, "pK-error", spec);
1555 		}
1556 
1557 		switch (kptr_restrict) {
1558 		case 0:
1559 			/* Always print %pK values */
1560 			break;
1561 		case 1: {
1562 			/*
1563 			 * Only print the real pointer value if the current
1564 			 * process has CAP_SYSLOG and is running with the
1565 			 * same credentials it started with. This is because
1566 			 * access to files is checked at open() time, but %pK
1567 			 * checks permission at read() time. We don't want to
1568 			 * leak pointer values if a binary opens a file using
1569 			 * %pK and then elevates privileges before reading it.
1570 			 */
1571 			const struct cred *cred = current_cred();
1572 
1573 			if (!has_capability_noaudit(current, CAP_SYSLOG) ||
1574 			    !uid_eq(cred->euid, cred->uid) ||
1575 			    !gid_eq(cred->egid, cred->gid))
1576 				ptr = NULL;
1577 			break;
1578 		}
1579 		case 2:
1580 		default:
1581 			/* Always print 0's for %pK */
1582 			ptr = NULL;
1583 			break;
1584 		}
1585 		break;
1586 
1587 	case 'N':
1588 		switch (fmt[1]) {
1589 		case 'F':
1590 			return netdev_feature_string(buf, end, ptr, spec);
1591 		}
1592 		break;
1593 	case 'a':
1594 		return address_val(buf, end, ptr, spec, fmt);
1595 	case 'd':
1596 		return dentry_name(buf, end, ptr, spec, fmt);
1597 	case 'C':
1598 		return clock(buf, end, ptr, spec, fmt);
1599 	case 'D':
1600 		return dentry_name(buf, end,
1601 				   ((const struct file *)ptr)->f_path.dentry,
1602 				   spec, fmt);
1603 	}
1604 	spec.flags |= SMALL;
1605 	if (spec.field_width == -1) {
1606 		spec.field_width = default_width;
1607 		spec.flags |= ZEROPAD;
1608 	}
1609 	spec.base = 16;
1610 
1611 	return number(buf, end, (unsigned long) ptr, spec);
1612 }
1613 
1614 /*
1615  * Helper function to decode printf style format.
1616  * Each call decode a token from the format and return the
1617  * number of characters read (or likely the delta where it wants
1618  * to go on the next call).
1619  * The decoded token is returned through the parameters
1620  *
1621  * 'h', 'l', or 'L' for integer fields
1622  * 'z' support added 23/7/1999 S.H.
1623  * 'z' changed to 'Z' --davidm 1/25/99
1624  * 't' added for ptrdiff_t
1625  *
1626  * @fmt: the format string
1627  * @type of the token returned
1628  * @flags: various flags such as +, -, # tokens..
1629  * @field_width: overwritten width
1630  * @base: base of the number (octal, hex, ...)
1631  * @precision: precision of a number
1632  * @qualifier: qualifier of a number (long, size_t, ...)
1633  */
1634 static noinline_for_stack
1635 int format_decode(const char *fmt, struct printf_spec *spec)
1636 {
1637 	const char *start = fmt;
1638 
1639 	/* we finished early by reading the field width */
1640 	if (spec->type == FORMAT_TYPE_WIDTH) {
1641 		if (spec->field_width < 0) {
1642 			spec->field_width = -spec->field_width;
1643 			spec->flags |= LEFT;
1644 		}
1645 		spec->type = FORMAT_TYPE_NONE;
1646 		goto precision;
1647 	}
1648 
1649 	/* we finished early by reading the precision */
1650 	if (spec->type == FORMAT_TYPE_PRECISION) {
1651 		if (spec->precision < 0)
1652 			spec->precision = 0;
1653 
1654 		spec->type = FORMAT_TYPE_NONE;
1655 		goto qualifier;
1656 	}
1657 
1658 	/* By default */
1659 	spec->type = FORMAT_TYPE_NONE;
1660 
1661 	for (; *fmt ; ++fmt) {
1662 		if (*fmt == '%')
1663 			break;
1664 	}
1665 
1666 	/* Return the current non-format string */
1667 	if (fmt != start || !*fmt)
1668 		return fmt - start;
1669 
1670 	/* Process flags */
1671 	spec->flags = 0;
1672 
1673 	while (1) { /* this also skips first '%' */
1674 		bool found = true;
1675 
1676 		++fmt;
1677 
1678 		switch (*fmt) {
1679 		case '-': spec->flags |= LEFT;    break;
1680 		case '+': spec->flags |= PLUS;    break;
1681 		case ' ': spec->flags |= SPACE;   break;
1682 		case '#': spec->flags |= SPECIAL; break;
1683 		case '0': spec->flags |= ZEROPAD; break;
1684 		default:  found = false;
1685 		}
1686 
1687 		if (!found)
1688 			break;
1689 	}
1690 
1691 	/* get field width */
1692 	spec->field_width = -1;
1693 
1694 	if (isdigit(*fmt))
1695 		spec->field_width = skip_atoi(&fmt);
1696 	else if (*fmt == '*') {
1697 		/* it's the next argument */
1698 		spec->type = FORMAT_TYPE_WIDTH;
1699 		return ++fmt - start;
1700 	}
1701 
1702 precision:
1703 	/* get the precision */
1704 	spec->precision = -1;
1705 	if (*fmt == '.') {
1706 		++fmt;
1707 		if (isdigit(*fmt)) {
1708 			spec->precision = skip_atoi(&fmt);
1709 			if (spec->precision < 0)
1710 				spec->precision = 0;
1711 		} else if (*fmt == '*') {
1712 			/* it's the next argument */
1713 			spec->type = FORMAT_TYPE_PRECISION;
1714 			return ++fmt - start;
1715 		}
1716 	}
1717 
1718 qualifier:
1719 	/* get the conversion qualifier */
1720 	spec->qualifier = -1;
1721 	if (*fmt == 'h' || _tolower(*fmt) == 'l' ||
1722 	    _tolower(*fmt) == 'z' || *fmt == 't') {
1723 		spec->qualifier = *fmt++;
1724 		if (unlikely(spec->qualifier == *fmt)) {
1725 			if (spec->qualifier == 'l') {
1726 				spec->qualifier = 'L';
1727 				++fmt;
1728 			} else if (spec->qualifier == 'h') {
1729 				spec->qualifier = 'H';
1730 				++fmt;
1731 			}
1732 		}
1733 	}
1734 
1735 	/* default base */
1736 	spec->base = 10;
1737 	switch (*fmt) {
1738 	case 'c':
1739 		spec->type = FORMAT_TYPE_CHAR;
1740 		return ++fmt - start;
1741 
1742 	case 's':
1743 		spec->type = FORMAT_TYPE_STR;
1744 		return ++fmt - start;
1745 
1746 	case 'p':
1747 		spec->type = FORMAT_TYPE_PTR;
1748 		return ++fmt - start;
1749 
1750 	case '%':
1751 		spec->type = FORMAT_TYPE_PERCENT_CHAR;
1752 		return ++fmt - start;
1753 
1754 	/* integer number formats - set up the flags and "break" */
1755 	case 'o':
1756 		spec->base = 8;
1757 		break;
1758 
1759 	case 'x':
1760 		spec->flags |= SMALL;
1761 
1762 	case 'X':
1763 		spec->base = 16;
1764 		break;
1765 
1766 	case 'd':
1767 	case 'i':
1768 		spec->flags |= SIGN;
1769 	case 'u':
1770 		break;
1771 
1772 	case 'n':
1773 		/*
1774 		 * Since %n poses a greater security risk than
1775 		 * utility, treat it as any other invalid or
1776 		 * unsupported format specifier.
1777 		 */
1778 		/* Fall-through */
1779 
1780 	default:
1781 		WARN_ONCE(1, "Please remove unsupported %%%c in format string\n", *fmt);
1782 		spec->type = FORMAT_TYPE_INVALID;
1783 		return fmt - start;
1784 	}
1785 
1786 	if (spec->qualifier == 'L')
1787 		spec->type = FORMAT_TYPE_LONG_LONG;
1788 	else if (spec->qualifier == 'l') {
1789 		BUILD_BUG_ON(FORMAT_TYPE_ULONG + SIGN != FORMAT_TYPE_LONG);
1790 		spec->type = FORMAT_TYPE_ULONG + (spec->flags & SIGN);
1791 	} else if (_tolower(spec->qualifier) == 'z') {
1792 		spec->type = FORMAT_TYPE_SIZE_T;
1793 	} else if (spec->qualifier == 't') {
1794 		spec->type = FORMAT_TYPE_PTRDIFF;
1795 	} else if (spec->qualifier == 'H') {
1796 		BUILD_BUG_ON(FORMAT_TYPE_UBYTE + SIGN != FORMAT_TYPE_BYTE);
1797 		spec->type = FORMAT_TYPE_UBYTE + (spec->flags & SIGN);
1798 	} else if (spec->qualifier == 'h') {
1799 		BUILD_BUG_ON(FORMAT_TYPE_USHORT + SIGN != FORMAT_TYPE_SHORT);
1800 		spec->type = FORMAT_TYPE_USHORT + (spec->flags & SIGN);
1801 	} else {
1802 		BUILD_BUG_ON(FORMAT_TYPE_UINT + SIGN != FORMAT_TYPE_INT);
1803 		spec->type = FORMAT_TYPE_UINT + (spec->flags & SIGN);
1804 	}
1805 
1806 	return ++fmt - start;
1807 }
1808 
1809 /**
1810  * vsnprintf - Format a string and place it in a buffer
1811  * @buf: The buffer to place the result into
1812  * @size: The size of the buffer, including the trailing null space
1813  * @fmt: The format string to use
1814  * @args: Arguments for the format string
1815  *
1816  * This function generally follows C99 vsnprintf, but has some
1817  * extensions and a few limitations:
1818  *
1819  * %n is unsupported
1820  * %p* is handled by pointer()
1821  *
1822  * See pointer() or Documentation/printk-formats.txt for more
1823  * extensive description.
1824  *
1825  * ** Please update the documentation in both places when making changes **
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  * If you're not already dealing with a va_list consider using snprintf().
1836  */
1837 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
1838 {
1839 	unsigned long long num;
1840 	char *str, *end;
1841 	struct printf_spec spec = {0};
1842 
1843 	/* Reject out-of-range values early.  Large positive sizes are
1844 	   used for unknown buffer sizes. */
1845 	if (WARN_ON_ONCE(size > INT_MAX))
1846 		return 0;
1847 
1848 	str = buf;
1849 	end = buf + size;
1850 
1851 	/* Make sure end is always >= buf */
1852 	if (end < buf) {
1853 		end = ((void *)-1);
1854 		size = end - buf;
1855 	}
1856 
1857 	while (*fmt) {
1858 		const char *old_fmt = fmt;
1859 		int read = format_decode(fmt, &spec);
1860 
1861 		fmt += read;
1862 
1863 		switch (spec.type) {
1864 		case FORMAT_TYPE_NONE: {
1865 			int copy = read;
1866 			if (str < end) {
1867 				if (copy > end - str)
1868 					copy = end - str;
1869 				memcpy(str, old_fmt, copy);
1870 			}
1871 			str += read;
1872 			break;
1873 		}
1874 
1875 		case FORMAT_TYPE_WIDTH:
1876 			spec.field_width = va_arg(args, int);
1877 			break;
1878 
1879 		case FORMAT_TYPE_PRECISION:
1880 			spec.precision = va_arg(args, int);
1881 			break;
1882 
1883 		case FORMAT_TYPE_CHAR: {
1884 			char c;
1885 
1886 			if (!(spec.flags & LEFT)) {
1887 				while (--spec.field_width > 0) {
1888 					if (str < end)
1889 						*str = ' ';
1890 					++str;
1891 
1892 				}
1893 			}
1894 			c = (unsigned char) va_arg(args, int);
1895 			if (str < end)
1896 				*str = c;
1897 			++str;
1898 			while (--spec.field_width > 0) {
1899 				if (str < end)
1900 					*str = ' ';
1901 				++str;
1902 			}
1903 			break;
1904 		}
1905 
1906 		case FORMAT_TYPE_STR:
1907 			str = string(str, end, va_arg(args, char *), spec);
1908 			break;
1909 
1910 		case FORMAT_TYPE_PTR:
1911 			str = pointer(fmt, str, end, va_arg(args, void *),
1912 				      spec);
1913 			while (isalnum(*fmt))
1914 				fmt++;
1915 			break;
1916 
1917 		case FORMAT_TYPE_PERCENT_CHAR:
1918 			if (str < end)
1919 				*str = '%';
1920 			++str;
1921 			break;
1922 
1923 		case FORMAT_TYPE_INVALID:
1924 			/*
1925 			 * Presumably the arguments passed gcc's type
1926 			 * checking, but there is no safe or sane way
1927 			 * for us to continue parsing the format and
1928 			 * fetching from the va_list; the remaining
1929 			 * specifiers and arguments would be out of
1930 			 * sync.
1931 			 */
1932 			goto out;
1933 
1934 		default:
1935 			switch (spec.type) {
1936 			case FORMAT_TYPE_LONG_LONG:
1937 				num = va_arg(args, long long);
1938 				break;
1939 			case FORMAT_TYPE_ULONG:
1940 				num = va_arg(args, unsigned long);
1941 				break;
1942 			case FORMAT_TYPE_LONG:
1943 				num = va_arg(args, long);
1944 				break;
1945 			case FORMAT_TYPE_SIZE_T:
1946 				if (spec.flags & SIGN)
1947 					num = va_arg(args, ssize_t);
1948 				else
1949 					num = va_arg(args, size_t);
1950 				break;
1951 			case FORMAT_TYPE_PTRDIFF:
1952 				num = va_arg(args, ptrdiff_t);
1953 				break;
1954 			case FORMAT_TYPE_UBYTE:
1955 				num = (unsigned char) va_arg(args, int);
1956 				break;
1957 			case FORMAT_TYPE_BYTE:
1958 				num = (signed char) va_arg(args, int);
1959 				break;
1960 			case FORMAT_TYPE_USHORT:
1961 				num = (unsigned short) va_arg(args, int);
1962 				break;
1963 			case FORMAT_TYPE_SHORT:
1964 				num = (short) va_arg(args, int);
1965 				break;
1966 			case FORMAT_TYPE_INT:
1967 				num = (int) va_arg(args, int);
1968 				break;
1969 			default:
1970 				num = va_arg(args, unsigned int);
1971 			}
1972 
1973 			str = number(str, end, num, spec);
1974 		}
1975 	}
1976 
1977 out:
1978 	if (size > 0) {
1979 		if (str < end)
1980 			*str = '\0';
1981 		else
1982 			end[-1] = '\0';
1983 	}
1984 
1985 	/* the trailing null byte doesn't count towards the total */
1986 	return str-buf;
1987 
1988 }
1989 EXPORT_SYMBOL(vsnprintf);
1990 
1991 /**
1992  * vscnprintf - Format a string and place it in a buffer
1993  * @buf: The buffer to place the result into
1994  * @size: The size of the buffer, including the trailing null space
1995  * @fmt: The format string to use
1996  * @args: Arguments for the format string
1997  *
1998  * The return value is the number of characters which have been written into
1999  * the @buf not including the trailing '\0'. If @size is == 0 the function
2000  * returns 0.
2001  *
2002  * If you're not already dealing with a va_list consider using scnprintf().
2003  *
2004  * See the vsnprintf() documentation for format string extensions over C99.
2005  */
2006 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
2007 {
2008 	int i;
2009 
2010 	i = vsnprintf(buf, size, fmt, args);
2011 
2012 	if (likely(i < size))
2013 		return i;
2014 	if (size != 0)
2015 		return size - 1;
2016 	return 0;
2017 }
2018 EXPORT_SYMBOL(vscnprintf);
2019 
2020 /**
2021  * snprintf - Format a string and place it in a buffer
2022  * @buf: The buffer to place the result into
2023  * @size: The size of the buffer, including the trailing null space
2024  * @fmt: The format string to use
2025  * @...: Arguments for the format string
2026  *
2027  * The return value is the number of characters which would be
2028  * generated for the given input, excluding the trailing null,
2029  * as per ISO C99.  If the return is greater than or equal to
2030  * @size, the resulting string is truncated.
2031  *
2032  * See the vsnprintf() documentation for format string extensions over C99.
2033  */
2034 int snprintf(char *buf, size_t size, const char *fmt, ...)
2035 {
2036 	va_list args;
2037 	int i;
2038 
2039 	va_start(args, fmt);
2040 	i = vsnprintf(buf, size, fmt, args);
2041 	va_end(args);
2042 
2043 	return i;
2044 }
2045 EXPORT_SYMBOL(snprintf);
2046 
2047 /**
2048  * scnprintf - Format a string and place it in a buffer
2049  * @buf: The buffer to place the result into
2050  * @size: The size of the buffer, including the trailing null space
2051  * @fmt: The format string to use
2052  * @...: Arguments for the format string
2053  *
2054  * The return value is the number of characters written into @buf not including
2055  * the trailing '\0'. If @size is == 0 the function returns 0.
2056  */
2057 
2058 int scnprintf(char *buf, size_t size, const char *fmt, ...)
2059 {
2060 	va_list args;
2061 	int i;
2062 
2063 	va_start(args, fmt);
2064 	i = vscnprintf(buf, size, fmt, args);
2065 	va_end(args);
2066 
2067 	return i;
2068 }
2069 EXPORT_SYMBOL(scnprintf);
2070 
2071 /**
2072  * vsprintf - Format a string and place it in a buffer
2073  * @buf: The buffer to place the result into
2074  * @fmt: The format string to use
2075  * @args: Arguments for the format string
2076  *
2077  * The function returns the number of characters written
2078  * into @buf. Use vsnprintf() or vscnprintf() in order to avoid
2079  * buffer overflows.
2080  *
2081  * If you're not already dealing with a va_list consider using sprintf().
2082  *
2083  * See the vsnprintf() documentation for format string extensions over C99.
2084  */
2085 int vsprintf(char *buf, const char *fmt, va_list args)
2086 {
2087 	return vsnprintf(buf, INT_MAX, fmt, args);
2088 }
2089 EXPORT_SYMBOL(vsprintf);
2090 
2091 /**
2092  * sprintf - Format a string and place it in a buffer
2093  * @buf: The buffer to place the result into
2094  * @fmt: The format string to use
2095  * @...: Arguments for the format string
2096  *
2097  * The function returns the number of characters written
2098  * into @buf. Use snprintf() or scnprintf() in order to avoid
2099  * buffer overflows.
2100  *
2101  * See the vsnprintf() documentation for format string extensions over C99.
2102  */
2103 int sprintf(char *buf, const char *fmt, ...)
2104 {
2105 	va_list args;
2106 	int i;
2107 
2108 	va_start(args, fmt);
2109 	i = vsnprintf(buf, INT_MAX, fmt, args);
2110 	va_end(args);
2111 
2112 	return i;
2113 }
2114 EXPORT_SYMBOL(sprintf);
2115 
2116 #ifdef CONFIG_BINARY_PRINTF
2117 /*
2118  * bprintf service:
2119  * vbin_printf() - VA arguments to binary data
2120  * bstr_printf() - Binary data to text string
2121  */
2122 
2123 /**
2124  * vbin_printf - Parse a format string and place args' binary value in a buffer
2125  * @bin_buf: The buffer to place args' binary value
2126  * @size: The size of the buffer(by words(32bits), not characters)
2127  * @fmt: The format string to use
2128  * @args: Arguments for the format string
2129  *
2130  * The format follows C99 vsnprintf, except %n is ignored, and its argument
2131  * is skipped.
2132  *
2133  * The return value is the number of words(32bits) which would be generated for
2134  * the given input.
2135  *
2136  * NOTE:
2137  * If the return value is greater than @size, the resulting bin_buf is NOT
2138  * valid for bstr_printf().
2139  */
2140 int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args)
2141 {
2142 	struct printf_spec spec = {0};
2143 	char *str, *end;
2144 
2145 	str = (char *)bin_buf;
2146 	end = (char *)(bin_buf + size);
2147 
2148 #define save_arg(type)							\
2149 do {									\
2150 	if (sizeof(type) == 8) {					\
2151 		unsigned long long value;				\
2152 		str = PTR_ALIGN(str, sizeof(u32));			\
2153 		value = va_arg(args, unsigned long long);		\
2154 		if (str + sizeof(type) <= end) {			\
2155 			*(u32 *)str = *(u32 *)&value;			\
2156 			*(u32 *)(str + 4) = *((u32 *)&value + 1);	\
2157 		}							\
2158 	} else {							\
2159 		unsigned long value;					\
2160 		str = PTR_ALIGN(str, sizeof(type));			\
2161 		value = va_arg(args, int);				\
2162 		if (str + sizeof(type) <= end)				\
2163 			*(typeof(type) *)str = (type)value;		\
2164 	}								\
2165 	str += sizeof(type);						\
2166 } while (0)
2167 
2168 	while (*fmt) {
2169 		int read = format_decode(fmt, &spec);
2170 
2171 		fmt += read;
2172 
2173 		switch (spec.type) {
2174 		case FORMAT_TYPE_NONE:
2175 		case FORMAT_TYPE_PERCENT_CHAR:
2176 			break;
2177 		case FORMAT_TYPE_INVALID:
2178 			goto out;
2179 
2180 		case FORMAT_TYPE_WIDTH:
2181 		case FORMAT_TYPE_PRECISION:
2182 			save_arg(int);
2183 			break;
2184 
2185 		case FORMAT_TYPE_CHAR:
2186 			save_arg(char);
2187 			break;
2188 
2189 		case FORMAT_TYPE_STR: {
2190 			const char *save_str = va_arg(args, char *);
2191 			size_t len;
2192 
2193 			if ((unsigned long)save_str > (unsigned long)-PAGE_SIZE
2194 					|| (unsigned long)save_str < PAGE_SIZE)
2195 				save_str = "(null)";
2196 			len = strlen(save_str) + 1;
2197 			if (str + len < end)
2198 				memcpy(str, save_str, len);
2199 			str += len;
2200 			break;
2201 		}
2202 
2203 		case FORMAT_TYPE_PTR:
2204 			save_arg(void *);
2205 			/* skip all alphanumeric pointer suffixes */
2206 			while (isalnum(*fmt))
2207 				fmt++;
2208 			break;
2209 
2210 		default:
2211 			switch (spec.type) {
2212 
2213 			case FORMAT_TYPE_LONG_LONG:
2214 				save_arg(long long);
2215 				break;
2216 			case FORMAT_TYPE_ULONG:
2217 			case FORMAT_TYPE_LONG:
2218 				save_arg(unsigned long);
2219 				break;
2220 			case FORMAT_TYPE_SIZE_T:
2221 				save_arg(size_t);
2222 				break;
2223 			case FORMAT_TYPE_PTRDIFF:
2224 				save_arg(ptrdiff_t);
2225 				break;
2226 			case FORMAT_TYPE_UBYTE:
2227 			case FORMAT_TYPE_BYTE:
2228 				save_arg(char);
2229 				break;
2230 			case FORMAT_TYPE_USHORT:
2231 			case FORMAT_TYPE_SHORT:
2232 				save_arg(short);
2233 				break;
2234 			default:
2235 				save_arg(int);
2236 			}
2237 		}
2238 	}
2239 
2240 out:
2241 	return (u32 *)(PTR_ALIGN(str, sizeof(u32))) - bin_buf;
2242 #undef save_arg
2243 }
2244 EXPORT_SYMBOL_GPL(vbin_printf);
2245 
2246 /**
2247  * bstr_printf - Format a string from binary arguments and place it in a buffer
2248  * @buf: The buffer to place the result into
2249  * @size: The size of the buffer, including the trailing null space
2250  * @fmt: The format string to use
2251  * @bin_buf: Binary arguments for the format string
2252  *
2253  * This function like C99 vsnprintf, but the difference is that vsnprintf gets
2254  * arguments from stack, and bstr_printf gets arguments from @bin_buf which is
2255  * a binary buffer that generated by vbin_printf.
2256  *
2257  * The format follows C99 vsnprintf, but has some extensions:
2258  *  see vsnprintf comment for details.
2259  *
2260  * The return value is the number of characters which would
2261  * be generated for the given input, excluding the trailing
2262  * '\0', as per ISO C99. If you want to have the exact
2263  * number of characters written into @buf as return value
2264  * (not including the trailing '\0'), use vscnprintf(). If the
2265  * return is greater than or equal to @size, the resulting
2266  * string is truncated.
2267  */
2268 int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf)
2269 {
2270 	struct printf_spec spec = {0};
2271 	char *str, *end;
2272 	const char *args = (const char *)bin_buf;
2273 
2274 	if (WARN_ON_ONCE(size > INT_MAX))
2275 		return 0;
2276 
2277 	str = buf;
2278 	end = buf + size;
2279 
2280 #define get_arg(type)							\
2281 ({									\
2282 	typeof(type) value;						\
2283 	if (sizeof(type) == 8) {					\
2284 		args = PTR_ALIGN(args, sizeof(u32));			\
2285 		*(u32 *)&value = *(u32 *)args;				\
2286 		*((u32 *)&value + 1) = *(u32 *)(args + 4);		\
2287 	} else {							\
2288 		args = PTR_ALIGN(args, sizeof(type));			\
2289 		value = *(typeof(type) *)args;				\
2290 	}								\
2291 	args += sizeof(type);						\
2292 	value;								\
2293 })
2294 
2295 	/* Make sure end is always >= buf */
2296 	if (end < buf) {
2297 		end = ((void *)-1);
2298 		size = end - buf;
2299 	}
2300 
2301 	while (*fmt) {
2302 		const char *old_fmt = fmt;
2303 		int read = format_decode(fmt, &spec);
2304 
2305 		fmt += read;
2306 
2307 		switch (spec.type) {
2308 		case FORMAT_TYPE_NONE: {
2309 			int copy = read;
2310 			if (str < end) {
2311 				if (copy > end - str)
2312 					copy = end - str;
2313 				memcpy(str, old_fmt, copy);
2314 			}
2315 			str += read;
2316 			break;
2317 		}
2318 
2319 		case FORMAT_TYPE_WIDTH:
2320 			spec.field_width = get_arg(int);
2321 			break;
2322 
2323 		case FORMAT_TYPE_PRECISION:
2324 			spec.precision = get_arg(int);
2325 			break;
2326 
2327 		case FORMAT_TYPE_CHAR: {
2328 			char c;
2329 
2330 			if (!(spec.flags & LEFT)) {
2331 				while (--spec.field_width > 0) {
2332 					if (str < end)
2333 						*str = ' ';
2334 					++str;
2335 				}
2336 			}
2337 			c = (unsigned char) get_arg(char);
2338 			if (str < end)
2339 				*str = c;
2340 			++str;
2341 			while (--spec.field_width > 0) {
2342 				if (str < end)
2343 					*str = ' ';
2344 				++str;
2345 			}
2346 			break;
2347 		}
2348 
2349 		case FORMAT_TYPE_STR: {
2350 			const char *str_arg = args;
2351 			args += strlen(str_arg) + 1;
2352 			str = string(str, end, (char *)str_arg, spec);
2353 			break;
2354 		}
2355 
2356 		case FORMAT_TYPE_PTR:
2357 			str = pointer(fmt, str, end, get_arg(void *), spec);
2358 			while (isalnum(*fmt))
2359 				fmt++;
2360 			break;
2361 
2362 		case FORMAT_TYPE_PERCENT_CHAR:
2363 			if (str < end)
2364 				*str = '%';
2365 			++str;
2366 			break;
2367 
2368 		case FORMAT_TYPE_INVALID:
2369 			goto out;
2370 
2371 		default: {
2372 			unsigned long long num;
2373 
2374 			switch (spec.type) {
2375 
2376 			case FORMAT_TYPE_LONG_LONG:
2377 				num = get_arg(long long);
2378 				break;
2379 			case FORMAT_TYPE_ULONG:
2380 			case FORMAT_TYPE_LONG:
2381 				num = get_arg(unsigned long);
2382 				break;
2383 			case FORMAT_TYPE_SIZE_T:
2384 				num = get_arg(size_t);
2385 				break;
2386 			case FORMAT_TYPE_PTRDIFF:
2387 				num = get_arg(ptrdiff_t);
2388 				break;
2389 			case FORMAT_TYPE_UBYTE:
2390 				num = get_arg(unsigned char);
2391 				break;
2392 			case FORMAT_TYPE_BYTE:
2393 				num = get_arg(signed char);
2394 				break;
2395 			case FORMAT_TYPE_USHORT:
2396 				num = get_arg(unsigned short);
2397 				break;
2398 			case FORMAT_TYPE_SHORT:
2399 				num = get_arg(short);
2400 				break;
2401 			case FORMAT_TYPE_UINT:
2402 				num = get_arg(unsigned int);
2403 				break;
2404 			default:
2405 				num = get_arg(int);
2406 			}
2407 
2408 			str = number(str, end, num, spec);
2409 		} /* default: */
2410 		} /* switch(spec.type) */
2411 	} /* while(*fmt) */
2412 
2413 out:
2414 	if (size > 0) {
2415 		if (str < end)
2416 			*str = '\0';
2417 		else
2418 			end[-1] = '\0';
2419 	}
2420 
2421 #undef get_arg
2422 
2423 	/* the trailing null byte doesn't count towards the total */
2424 	return str - buf;
2425 }
2426 EXPORT_SYMBOL_GPL(bstr_printf);
2427 
2428 /**
2429  * bprintf - Parse a format string and place args' binary value in a buffer
2430  * @bin_buf: The buffer to place args' binary value
2431  * @size: The size of the buffer(by words(32bits), not characters)
2432  * @fmt: The format string to use
2433  * @...: Arguments for the format string
2434  *
2435  * The function returns the number of words(u32) written
2436  * into @bin_buf.
2437  */
2438 int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...)
2439 {
2440 	va_list args;
2441 	int ret;
2442 
2443 	va_start(args, fmt);
2444 	ret = vbin_printf(bin_buf, size, fmt, args);
2445 	va_end(args);
2446 
2447 	return ret;
2448 }
2449 EXPORT_SYMBOL_GPL(bprintf);
2450 
2451 #endif /* CONFIG_BINARY_PRINTF */
2452 
2453 /**
2454  * vsscanf - Unformat a buffer into a list of arguments
2455  * @buf:	input buffer
2456  * @fmt:	format of buffer
2457  * @args:	arguments
2458  */
2459 int vsscanf(const char *buf, const char *fmt, va_list args)
2460 {
2461 	const char *str = buf;
2462 	char *next;
2463 	char digit;
2464 	int num = 0;
2465 	u8 qualifier;
2466 	unsigned int base;
2467 	union {
2468 		long long s;
2469 		unsigned long long u;
2470 	} val;
2471 	s16 field_width;
2472 	bool is_sign;
2473 
2474 	while (*fmt) {
2475 		/* skip any white space in format */
2476 		/* white space in format matchs any amount of
2477 		 * white space, including none, in the input.
2478 		 */
2479 		if (isspace(*fmt)) {
2480 			fmt = skip_spaces(++fmt);
2481 			str = skip_spaces(str);
2482 		}
2483 
2484 		/* anything that is not a conversion must match exactly */
2485 		if (*fmt != '%' && *fmt) {
2486 			if (*fmt++ != *str++)
2487 				break;
2488 			continue;
2489 		}
2490 
2491 		if (!*fmt)
2492 			break;
2493 		++fmt;
2494 
2495 		/* skip this conversion.
2496 		 * advance both strings to next white space
2497 		 */
2498 		if (*fmt == '*') {
2499 			if (!*str)
2500 				break;
2501 			while (!isspace(*fmt) && *fmt != '%' && *fmt)
2502 				fmt++;
2503 			while (!isspace(*str) && *str)
2504 				str++;
2505 			continue;
2506 		}
2507 
2508 		/* get field width */
2509 		field_width = -1;
2510 		if (isdigit(*fmt)) {
2511 			field_width = skip_atoi(&fmt);
2512 			if (field_width <= 0)
2513 				break;
2514 		}
2515 
2516 		/* get conversion qualifier */
2517 		qualifier = -1;
2518 		if (*fmt == 'h' || _tolower(*fmt) == 'l' ||
2519 		    _tolower(*fmt) == 'z') {
2520 			qualifier = *fmt++;
2521 			if (unlikely(qualifier == *fmt)) {
2522 				if (qualifier == 'h') {
2523 					qualifier = 'H';
2524 					fmt++;
2525 				} else if (qualifier == 'l') {
2526 					qualifier = 'L';
2527 					fmt++;
2528 				}
2529 			}
2530 		}
2531 
2532 		if (!*fmt)
2533 			break;
2534 
2535 		if (*fmt == 'n') {
2536 			/* return number of characters read so far */
2537 			*va_arg(args, int *) = str - buf;
2538 			++fmt;
2539 			continue;
2540 		}
2541 
2542 		if (!*str)
2543 			break;
2544 
2545 		base = 10;
2546 		is_sign = false;
2547 
2548 		switch (*fmt++) {
2549 		case 'c':
2550 		{
2551 			char *s = (char *)va_arg(args, char*);
2552 			if (field_width == -1)
2553 				field_width = 1;
2554 			do {
2555 				*s++ = *str++;
2556 			} while (--field_width > 0 && *str);
2557 			num++;
2558 		}
2559 		continue;
2560 		case 's':
2561 		{
2562 			char *s = (char *)va_arg(args, char *);
2563 			if (field_width == -1)
2564 				field_width = SHRT_MAX;
2565 			/* first, skip leading white space in buffer */
2566 			str = skip_spaces(str);
2567 
2568 			/* now copy until next white space */
2569 			while (*str && !isspace(*str) && field_width--)
2570 				*s++ = *str++;
2571 			*s = '\0';
2572 			num++;
2573 		}
2574 		continue;
2575 		case 'o':
2576 			base = 8;
2577 			break;
2578 		case 'x':
2579 		case 'X':
2580 			base = 16;
2581 			break;
2582 		case 'i':
2583 			base = 0;
2584 		case 'd':
2585 			is_sign = true;
2586 		case 'u':
2587 			break;
2588 		case '%':
2589 			/* looking for '%' in str */
2590 			if (*str++ != '%')
2591 				return num;
2592 			continue;
2593 		default:
2594 			/* invalid format; stop here */
2595 			return num;
2596 		}
2597 
2598 		/* have some sort of integer conversion.
2599 		 * first, skip white space in buffer.
2600 		 */
2601 		str = skip_spaces(str);
2602 
2603 		digit = *str;
2604 		if (is_sign && digit == '-')
2605 			digit = *(str + 1);
2606 
2607 		if (!digit
2608 		    || (base == 16 && !isxdigit(digit))
2609 		    || (base == 10 && !isdigit(digit))
2610 		    || (base == 8 && (!isdigit(digit) || digit > '7'))
2611 		    || (base == 0 && !isdigit(digit)))
2612 			break;
2613 
2614 		if (is_sign)
2615 			val.s = qualifier != 'L' ?
2616 				simple_strtol(str, &next, base) :
2617 				simple_strtoll(str, &next, base);
2618 		else
2619 			val.u = qualifier != 'L' ?
2620 				simple_strtoul(str, &next, base) :
2621 				simple_strtoull(str, &next, base);
2622 
2623 		if (field_width > 0 && next - str > field_width) {
2624 			if (base == 0)
2625 				_parse_integer_fixup_radix(str, &base);
2626 			while (next - str > field_width) {
2627 				if (is_sign)
2628 					val.s = div_s64(val.s, base);
2629 				else
2630 					val.u = div_u64(val.u, base);
2631 				--next;
2632 			}
2633 		}
2634 
2635 		switch (qualifier) {
2636 		case 'H':	/* that's 'hh' in format */
2637 			if (is_sign)
2638 				*va_arg(args, signed char *) = val.s;
2639 			else
2640 				*va_arg(args, unsigned char *) = val.u;
2641 			break;
2642 		case 'h':
2643 			if (is_sign)
2644 				*va_arg(args, short *) = val.s;
2645 			else
2646 				*va_arg(args, unsigned short *) = val.u;
2647 			break;
2648 		case 'l':
2649 			if (is_sign)
2650 				*va_arg(args, long *) = val.s;
2651 			else
2652 				*va_arg(args, unsigned long *) = val.u;
2653 			break;
2654 		case 'L':
2655 			if (is_sign)
2656 				*va_arg(args, long long *) = val.s;
2657 			else
2658 				*va_arg(args, unsigned long long *) = val.u;
2659 			break;
2660 		case 'Z':
2661 		case 'z':
2662 			*va_arg(args, size_t *) = val.u;
2663 			break;
2664 		default:
2665 			if (is_sign)
2666 				*va_arg(args, int *) = val.s;
2667 			else
2668 				*va_arg(args, unsigned int *) = val.u;
2669 			break;
2670 		}
2671 		num++;
2672 
2673 		if (!next)
2674 			break;
2675 		str = next;
2676 	}
2677 
2678 	return num;
2679 }
2680 EXPORT_SYMBOL(vsscanf);
2681 
2682 /**
2683  * sscanf - Unformat a buffer into a list of arguments
2684  * @buf:	input buffer
2685  * @fmt:	formatting of buffer
2686  * @...:	resulting arguments
2687  */
2688 int sscanf(const char *buf, const char *fmt, ...)
2689 {
2690 	va_list args;
2691 	int i;
2692 
2693 	va_start(args, fmt);
2694 	i = vsscanf(buf, fmt, args);
2695 	va_end(args);
2696 
2697 	return i;
2698 }
2699 EXPORT_SYMBOL(sscanf);
2700