Merge branch 'cpuinit_phase2' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg...
[linux-2.6.git] / lib / vsprintf.c
blob739a36366b79ad1b5515aa1aec275222a28d2e7f
1 /*
2 * linux/lib/vsprintf.c
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
7 /* vsprintf.c -- Lars Wirzenius & Linus Torvalds. */
8 /*
9 * Wirzenius wrote this portably, Torvalds fucked it up :-)
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
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>
31 #include <asm/page.h> /* for PAGE_SIZE */
32 #include <asm/sections.h> /* for dereference_function_descriptor() */
34 #include "kstrtox.h"
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
42 * This function is obsolete. Please use kstrtoull instead.
44 unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base)
46 unsigned long long result;
47 unsigned int rv;
49 cp = _parse_integer_fixup_radix(cp, &base);
50 rv = _parse_integer(cp, base, &result);
51 /* FIXME */
52 cp += (rv & ~KSTRTOX_OVERFLOW);
54 if (endp)
55 *endp = (char *)cp;
57 return result;
59 EXPORT_SYMBOL(simple_strtoull);
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
67 * This function is obsolete. Please use kstrtoul instead.
69 unsigned long simple_strtoul(const char *cp, char **endp, unsigned int base)
71 return simple_strtoull(cp, endp, base);
73 EXPORT_SYMBOL(simple_strtoul);
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
81 * This function is obsolete. Please use kstrtol instead.
83 long simple_strtol(const char *cp, char **endp, unsigned int base)
85 if (*cp == '-')
86 return -simple_strtoul(cp + 1, endp, base);
88 return simple_strtoul(cp, endp, base);
90 EXPORT_SYMBOL(simple_strtol);
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
98 * This function is obsolete. Please use kstrtoll instead.
100 long long simple_strtoll(const char *cp, char **endp, unsigned int base)
102 if (*cp == '-')
103 return -simple_strtoull(cp + 1, endp, base);
105 return simple_strtoull(cp, endp, base);
107 EXPORT_SYMBOL(simple_strtoll);
109 static noinline_for_stack
110 int skip_atoi(const char **s)
112 int i = 0;
114 while (isdigit(**s))
115 i = i*10 + *((*s)++) - '0';
117 return i;
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).
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)
132 unsigned r;
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>
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;
173 #endif
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.
179 static noinline_for_stack
180 char *put_dec_trunc8(char *buf, unsigned r)
182 unsigned q;
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;
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;
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.
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.
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.
221 * Else (if long is 32 bits and long long is 64 bits) we use second one.
224 #if BITS_PER_LONG != 32 || BITS_PER_LONG_LONG != 64
226 /* First algorithm: generic */
228 static
229 char *put_dec(char *buf, unsigned long long n)
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);
237 return put_dec_trunc8(buf, n);
240 #else
242 /* Second algorithm: valid only for 64-bit long longs */
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)
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';
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).
265 static
266 unsigned put_dec_helper4(char *buf, unsigned x)
268 uint32_t q = (x * (uint64_t)0x346DC5D7) >> 43;
270 put_dec_full4(buf, x - q * 10000);
271 return q;
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.
279 static
280 char *put_dec(char *buf, unsigned long long n)
282 uint32_t d3, d2, d1, q, h;
284 if (n < 100*1000*1000)
285 return put_dec_trunc8(buf, n);
287 d1 = ((uint32_t)n >> 16); /* implicit "& 0xffff" */
288 h = (n >> 32);
289 d2 = (h ) & 0xffff;
290 d3 = (h >> 16); /* implicit "& 0xffff" */
292 q = 656 * d3 + 7296 * d2 + 5536 * d1 + ((uint32_t)n & 0xffff);
293 q = put_dec_helper4(buf, q);
295 q += 7671 * d3 + 9496 * d2 + 6 * d1;
296 q = put_dec_helper4(buf+4, q);
298 q += 4749 * d3 + 42 * d2;
299 q = put_dec_helper4(buf+8, q);
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;
308 return buf;
311 #endif
314 * Convert passed number to decimal string.
315 * Returns the length of string. On buffer overflow, returns 0.
317 * If speed is not important, use snprintf(). It's easy to read the code.
319 int num_to_str(char *buf, int size, unsigned long long num)
321 char tmp[sizeof(num) * 3];
322 int idx, len;
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;
332 if (len > size)
333 return 0;
334 for (idx = 0; idx < len; ++idx)
335 buf[idx] = tmp[len - idx - 1];
336 return len;
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" */
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
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 */
379 static noinline_for_stack
380 char *number(char *buf, char *end, unsigned long long num,
381 struct printf_spec spec)
383 /* we are called with base 8, 10 or 16, only, thus don't need "G..." */
384 static const char digits[16] = "0123456789ABCDEF"; /* "GHIJKLMNOPQRSTUVWXYZ"; */
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;
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--;
412 if (need_pfx) {
413 if (spec.base == 16)
414 spec.field_width -= 2;
415 else if (!is_zero)
416 spec.field_width--;
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);
428 else if (spec.base != 10) { /* 8 or 16 */
429 int mask = spec.base - 1;
430 int shift = 3;
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;
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;
454 /* sign */
455 if (sign) {
456 if (buf < end)
457 *buf = sign;
458 ++buf;
460 /* "0x" / "0" prefix */
461 if (need_pfx) {
462 if (spec.base == 16 || !is_zero) {
463 if (buf < end)
464 *buf = '0';
465 ++buf;
467 if (spec.base == 16) {
468 if (buf < end)
469 *buf = ('X' | locase);
470 ++buf;
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;
482 /* hmm even more zero padding? */
483 while (i <= --spec.precision) {
484 if (buf < end)
485 *buf = '0';
486 ++buf;
488 /* actual digits of result */
489 while (--i >= 0) {
490 if (buf < end)
491 *buf = tmp[i];
492 ++buf;
494 /* trailing space padding */
495 while (--spec.field_width >= 0) {
496 if (buf < end)
497 *buf = ' ';
498 ++buf;
501 return buf;
504 static noinline_for_stack
505 char *string(char *buf, char *end, const char *s, struct printf_spec spec)
507 int len, i;
509 if ((unsigned long)s < PAGE_SIZE)
510 s = "(null)";
512 len = strnlen(s, spec.precision);
514 if (!(spec.flags & LEFT)) {
515 while (len < spec.field_width--) {
516 if (buf < end)
517 *buf = ' ';
518 ++buf;
521 for (i = 0; i < len; ++i) {
522 if (buf < end)
523 *buf = *s;
524 ++buf; ++s;
526 while (len < spec.field_width--) {
527 if (buf < end)
528 *buf = ' ';
529 ++buf;
532 return buf;
535 static noinline_for_stack
536 char *symbol_string(char *buf, char *end, void *ptr,
537 struct printf_spec spec, const char *fmt)
539 unsigned long value;
540 #ifdef CONFIG_KALLSYMS
541 char sym[KSYM_SYMBOL_LEN];
542 #endif
544 if (fmt[1] == 'R')
545 ptr = __builtin_extract_return_addr(ptr);
546 value = (unsigned long)ptr;
548 #ifdef CONFIG_KALLSYMS
549 if (*fmt == 'B')
550 sprint_backtrace(sym, value);
551 else if (*fmt != 'f' && *fmt != 's')
552 sprint_symbol(sym, value);
553 else
554 sprint_symbol_no_offset(sym, value);
556 return string(buf, end, sym, spec);
557 #else
558 spec.field_width = 2 * sizeof(void *);
559 spec.flags |= SPECIAL | SMALL | ZEROPAD;
560 spec.base = 16;
562 return number(buf, end, value, spec);
563 #endif
566 static noinline_for_stack
567 char *resource_string(char *buf, char *end, struct resource *res,
568 struct printf_spec spec, const char *fmt)
570 #ifndef IO_RSRC_PRINTK_SIZE
571 #define IO_RSRC_PRINTK_SIZE 6
572 #endif
574 #ifndef MEM_RSRC_PRINTK_SIZE
575 #define MEM_RSRC_PRINTK_SIZE 10
576 #endif
577 static const struct printf_spec io_spec = {
578 .base = 16,
579 .field_width = IO_RSRC_PRINTK_SIZE,
580 .precision = -1,
581 .flags = SPECIAL | SMALL | ZEROPAD,
583 static const struct printf_spec mem_spec = {
584 .base = 16,
585 .field_width = MEM_RSRC_PRINTK_SIZE,
586 .precision = -1,
587 .flags = SPECIAL | SMALL | ZEROPAD,
589 static const struct printf_spec bus_spec = {
590 .base = 16,
591 .field_width = 2,
592 .precision = -1,
593 .flags = SMALL | ZEROPAD,
595 static const struct printf_spec dec_spec = {
596 .base = 10,
597 .precision = -1,
598 .flags = 0,
600 static const struct printf_spec str_spec = {
601 .field_width = -1,
602 .precision = 10,
603 .flags = LEFT,
605 static const struct printf_spec flag_spec = {
606 .base = 16,
607 .precision = -1,
608 .flags = SPECIAL | SMALL,
611 /* 32-bit res (sizeof==4): 10 chars in dec, 10 in hex ("0x" + 8)
612 * 64-bit res (sizeof==8): 20 chars in dec, 18 in hex ("0x" + 16) */
613 #define RSRC_BUF_SIZE ((2 * sizeof(resource_size_t)) + 4)
614 #define FLAG_BUF_SIZE (2 * sizeof(res->flags))
615 #define DECODED_BUF_SIZE sizeof("[mem - 64bit pref window disabled]")
616 #define RAW_BUF_SIZE sizeof("[mem - flags 0x]")
617 char sym[max(2*RSRC_BUF_SIZE + DECODED_BUF_SIZE,
618 2*RSRC_BUF_SIZE + FLAG_BUF_SIZE + RAW_BUF_SIZE)];
620 char *p = sym, *pend = sym + sizeof(sym);
621 int decode = (fmt[0] == 'R') ? 1 : 0;
622 const struct printf_spec *specp;
624 *p++ = '[';
625 if (res->flags & IORESOURCE_IO) {
626 p = string(p, pend, "io ", str_spec);
627 specp = &io_spec;
628 } else if (res->flags & IORESOURCE_MEM) {
629 p = string(p, pend, "mem ", str_spec);
630 specp = &mem_spec;
631 } else if (res->flags & IORESOURCE_IRQ) {
632 p = string(p, pend, "irq ", str_spec);
633 specp = &dec_spec;
634 } else if (res->flags & IORESOURCE_DMA) {
635 p = string(p, pend, "dma ", str_spec);
636 specp = &dec_spec;
637 } else if (res->flags & IORESOURCE_BUS) {
638 p = string(p, pend, "bus ", str_spec);
639 specp = &bus_spec;
640 } else {
641 p = string(p, pend, "??? ", str_spec);
642 specp = &mem_spec;
643 decode = 0;
645 p = number(p, pend, res->start, *specp);
646 if (res->start != res->end) {
647 *p++ = '-';
648 p = number(p, pend, res->end, *specp);
650 if (decode) {
651 if (res->flags & IORESOURCE_MEM_64)
652 p = string(p, pend, " 64bit", str_spec);
653 if (res->flags & IORESOURCE_PREFETCH)
654 p = string(p, pend, " pref", str_spec);
655 if (res->flags & IORESOURCE_WINDOW)
656 p = string(p, pend, " window", str_spec);
657 if (res->flags & IORESOURCE_DISABLED)
658 p = string(p, pend, " disabled", str_spec);
659 } else {
660 p = string(p, pend, " flags ", str_spec);
661 p = number(p, pend, res->flags, flag_spec);
663 *p++ = ']';
664 *p = '\0';
666 return string(buf, end, sym, spec);
669 static noinline_for_stack
670 char *hex_string(char *buf, char *end, u8 *addr, struct printf_spec spec,
671 const char *fmt)
673 int i, len = 1; /* if we pass '%ph[CDN]', field width remains
674 negative value, fallback to the default */
675 char separator;
677 if (spec.field_width == 0)
678 /* nothing to print */
679 return buf;
681 if (ZERO_OR_NULL_PTR(addr))
682 /* NULL pointer */
683 return string(buf, end, NULL, spec);
685 switch (fmt[1]) {
686 case 'C':
687 separator = ':';
688 break;
689 case 'D':
690 separator = '-';
691 break;
692 case 'N':
693 separator = 0;
694 break;
695 default:
696 separator = ' ';
697 break;
700 if (spec.field_width > 0)
701 len = min_t(int, spec.field_width, 64);
703 for (i = 0; i < len && buf < end - 1; i++) {
704 buf = hex_byte_pack(buf, addr[i]);
706 if (buf < end && separator && i != len - 1)
707 *buf++ = separator;
710 return buf;
713 static noinline_for_stack
714 char *mac_address_string(char *buf, char *end, u8 *addr,
715 struct printf_spec spec, const char *fmt)
717 char mac_addr[sizeof("xx:xx:xx:xx:xx:xx")];
718 char *p = mac_addr;
719 int i;
720 char separator;
721 bool reversed = false;
723 switch (fmt[1]) {
724 case 'F':
725 separator = '-';
726 break;
728 case 'R':
729 reversed = true;
730 /* fall through */
732 default:
733 separator = ':';
734 break;
737 for (i = 0; i < 6; i++) {
738 if (reversed)
739 p = hex_byte_pack(p, addr[5 - i]);
740 else
741 p = hex_byte_pack(p, addr[i]);
743 if (fmt[0] == 'M' && i != 5)
744 *p++ = separator;
746 *p = '\0';
748 return string(buf, end, mac_addr, spec);
751 static noinline_for_stack
752 char *ip4_string(char *p, const u8 *addr, const char *fmt)
754 int i;
755 bool leading_zeros = (fmt[0] == 'i');
756 int index;
757 int step;
759 switch (fmt[2]) {
760 case 'h':
761 #ifdef __BIG_ENDIAN
762 index = 0;
763 step = 1;
764 #else
765 index = 3;
766 step = -1;
767 #endif
768 break;
769 case 'l':
770 index = 3;
771 step = -1;
772 break;
773 case 'n':
774 case 'b':
775 default:
776 index = 0;
777 step = 1;
778 break;
780 for (i = 0; i < 4; i++) {
781 char temp[3]; /* hold each IP quad in reverse order */
782 int digits = put_dec_trunc8(temp, addr[index]) - temp;
783 if (leading_zeros) {
784 if (digits < 3)
785 *p++ = '0';
786 if (digits < 2)
787 *p++ = '0';
789 /* reverse the digits in the quad */
790 while (digits--)
791 *p++ = temp[digits];
792 if (i < 3)
793 *p++ = '.';
794 index += step;
796 *p = '\0';
798 return p;
801 static noinline_for_stack
802 char *ip6_compressed_string(char *p, const char *addr)
804 int i, j, range;
805 unsigned char zerolength[8];
806 int longest = 1;
807 int colonpos = -1;
808 u16 word;
809 u8 hi, lo;
810 bool needcolon = false;
811 bool useIPv4;
812 struct in6_addr in6;
814 memcpy(&in6, addr, sizeof(struct in6_addr));
816 useIPv4 = ipv6_addr_v4mapped(&in6) || ipv6_addr_is_isatap(&in6);
818 memset(zerolength, 0, sizeof(zerolength));
820 if (useIPv4)
821 range = 6;
822 else
823 range = 8;
825 /* find position of longest 0 run */
826 for (i = 0; i < range; i++) {
827 for (j = i; j < range; j++) {
828 if (in6.s6_addr16[j] != 0)
829 break;
830 zerolength[i]++;
833 for (i = 0; i < range; i++) {
834 if (zerolength[i] > longest) {
835 longest = zerolength[i];
836 colonpos = i;
839 if (longest == 1) /* don't compress a single 0 */
840 colonpos = -1;
842 /* emit address */
843 for (i = 0; i < range; i++) {
844 if (i == colonpos) {
845 if (needcolon || i == 0)
846 *p++ = ':';
847 *p++ = ':';
848 needcolon = false;
849 i += longest - 1;
850 continue;
852 if (needcolon) {
853 *p++ = ':';
854 needcolon = false;
856 /* hex u16 without leading 0s */
857 word = ntohs(in6.s6_addr16[i]);
858 hi = word >> 8;
859 lo = word & 0xff;
860 if (hi) {
861 if (hi > 0x0f)
862 p = hex_byte_pack(p, hi);
863 else
864 *p++ = hex_asc_lo(hi);
865 p = hex_byte_pack(p, lo);
867 else if (lo > 0x0f)
868 p = hex_byte_pack(p, lo);
869 else
870 *p++ = hex_asc_lo(lo);
871 needcolon = true;
874 if (useIPv4) {
875 if (needcolon)
876 *p++ = ':';
877 p = ip4_string(p, &in6.s6_addr[12], "I4");
879 *p = '\0';
881 return p;
884 static noinline_for_stack
885 char *ip6_string(char *p, const char *addr, const char *fmt)
887 int i;
889 for (i = 0; i < 8; i++) {
890 p = hex_byte_pack(p, *addr++);
891 p = hex_byte_pack(p, *addr++);
892 if (fmt[0] == 'I' && i != 7)
893 *p++ = ':';
895 *p = '\0';
897 return p;
900 static noinline_for_stack
901 char *ip6_addr_string(char *buf, char *end, const u8 *addr,
902 struct printf_spec spec, const char *fmt)
904 char ip6_addr[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255")];
906 if (fmt[0] == 'I' && fmt[2] == 'c')
907 ip6_compressed_string(ip6_addr, addr);
908 else
909 ip6_string(ip6_addr, addr, fmt);
911 return string(buf, end, ip6_addr, spec);
914 static noinline_for_stack
915 char *ip4_addr_string(char *buf, char *end, const u8 *addr,
916 struct printf_spec spec, const char *fmt)
918 char ip4_addr[sizeof("255.255.255.255")];
920 ip4_string(ip4_addr, addr, fmt);
922 return string(buf, end, ip4_addr, spec);
925 static noinline_for_stack
926 char *ip6_addr_string_sa(char *buf, char *end, const struct sockaddr_in6 *sa,
927 struct printf_spec spec, const char *fmt)
929 bool have_p = false, have_s = false, have_f = false, have_c = false;
930 char ip6_addr[sizeof("[xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255]") +
931 sizeof(":12345") + sizeof("/123456789") +
932 sizeof("%1234567890")];
933 char *p = ip6_addr, *pend = ip6_addr + sizeof(ip6_addr);
934 const u8 *addr = (const u8 *) &sa->sin6_addr;
935 char fmt6[2] = { fmt[0], '6' };
936 u8 off = 0;
938 fmt++;
939 while (isalpha(*++fmt)) {
940 switch (*fmt) {
941 case 'p':
942 have_p = true;
943 break;
944 case 'f':
945 have_f = true;
946 break;
947 case 's':
948 have_s = true;
949 break;
950 case 'c':
951 have_c = true;
952 break;
956 if (have_p || have_s || have_f) {
957 *p = '[';
958 off = 1;
961 if (fmt6[0] == 'I' && have_c)
962 p = ip6_compressed_string(ip6_addr + off, addr);
963 else
964 p = ip6_string(ip6_addr + off, addr, fmt6);
966 if (have_p || have_s || have_f)
967 *p++ = ']';
969 if (have_p) {
970 *p++ = ':';
971 p = number(p, pend, ntohs(sa->sin6_port), spec);
973 if (have_f) {
974 *p++ = '/';
975 p = number(p, pend, ntohl(sa->sin6_flowinfo &
976 IPV6_FLOWINFO_MASK), spec);
978 if (have_s) {
979 *p++ = '%';
980 p = number(p, pend, sa->sin6_scope_id, spec);
982 *p = '\0';
984 return string(buf, end, ip6_addr, spec);
987 static noinline_for_stack
988 char *ip4_addr_string_sa(char *buf, char *end, const struct sockaddr_in *sa,
989 struct printf_spec spec, const char *fmt)
991 bool have_p = false;
992 char *p, ip4_addr[sizeof("255.255.255.255") + sizeof(":12345")];
993 char *pend = ip4_addr + sizeof(ip4_addr);
994 const u8 *addr = (const u8 *) &sa->sin_addr.s_addr;
995 char fmt4[3] = { fmt[0], '4', 0 };
997 fmt++;
998 while (isalpha(*++fmt)) {
999 switch (*fmt) {
1000 case 'p':
1001 have_p = true;
1002 break;
1003 case 'h':
1004 case 'l':
1005 case 'n':
1006 case 'b':
1007 fmt4[2] = *fmt;
1008 break;
1012 p = ip4_string(ip4_addr, addr, fmt4);
1013 if (have_p) {
1014 *p++ = ':';
1015 p = number(p, pend, ntohs(sa->sin_port), spec);
1017 *p = '\0';
1019 return string(buf, end, ip4_addr, spec);
1022 static noinline_for_stack
1023 char *uuid_string(char *buf, char *end, const u8 *addr,
1024 struct printf_spec spec, const char *fmt)
1026 char uuid[sizeof("xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx")];
1027 char *p = uuid;
1028 int i;
1029 static const u8 be[16] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
1030 static const u8 le[16] = {3,2,1,0,5,4,7,6,8,9,10,11,12,13,14,15};
1031 const u8 *index = be;
1032 bool uc = false;
1034 switch (*(++fmt)) {
1035 case 'L':
1036 uc = true; /* fall-through */
1037 case 'l':
1038 index = le;
1039 break;
1040 case 'B':
1041 uc = true;
1042 break;
1045 for (i = 0; i < 16; i++) {
1046 p = hex_byte_pack(p, addr[index[i]]);
1047 switch (i) {
1048 case 3:
1049 case 5:
1050 case 7:
1051 case 9:
1052 *p++ = '-';
1053 break;
1057 *p = 0;
1059 if (uc) {
1060 p = uuid;
1061 do {
1062 *p = toupper(*p);
1063 } while (*(++p));
1066 return string(buf, end, uuid, spec);
1069 static
1070 char *netdev_feature_string(char *buf, char *end, const u8 *addr,
1071 struct printf_spec spec)
1073 spec.flags |= SPECIAL | SMALL | ZEROPAD;
1074 if (spec.field_width == -1)
1075 spec.field_width = 2 + 2 * sizeof(netdev_features_t);
1076 spec.base = 16;
1078 return number(buf, end, *(const netdev_features_t *)addr, spec);
1081 int kptr_restrict __read_mostly;
1084 * Show a '%p' thing. A kernel extension is that the '%p' is followed
1085 * by an extra set of alphanumeric characters that are extended format
1086 * specifiers.
1088 * Right now we handle:
1090 * - 'F' For symbolic function descriptor pointers with offset
1091 * - 'f' For simple symbolic function names without offset
1092 * - 'S' For symbolic direct pointers with offset
1093 * - 's' For symbolic direct pointers without offset
1094 * - '[FfSs]R' as above with __builtin_extract_return_addr() translation
1095 * - 'B' For backtraced symbolic direct pointers with offset
1096 * - 'R' For decoded struct resource, e.g., [mem 0x0-0x1f 64bit pref]
1097 * - 'r' For raw struct resource, e.g., [mem 0x0-0x1f flags 0x201]
1098 * - 'M' For a 6-byte MAC address, it prints the address in the
1099 * usual colon-separated hex notation
1100 * - 'm' For a 6-byte MAC address, it prints the hex address without colons
1101 * - 'MF' For a 6-byte MAC FDDI address, it prints the address
1102 * with a dash-separated hex notation
1103 * - '[mM]R' For a 6-byte MAC address, Reverse order (Bluetooth)
1104 * - 'I' [46] for IPv4/IPv6 addresses printed in the usual way
1105 * IPv4 uses dot-separated decimal without leading 0's (1.2.3.4)
1106 * IPv6 uses colon separated network-order 16 bit hex with leading 0's
1107 * [S][pfs]
1108 * Generic IPv4/IPv6 address (struct sockaddr *) that falls back to
1109 * [4] or [6] and is able to print port [p], flowinfo [f], scope [s]
1110 * - 'i' [46] for 'raw' IPv4/IPv6 addresses
1111 * IPv6 omits the colons (01020304...0f)
1112 * IPv4 uses dot-separated decimal with leading 0's (010.123.045.006)
1113 * [S][pfs]
1114 * Generic IPv4/IPv6 address (struct sockaddr *) that falls back to
1115 * [4] or [6] and is able to print port [p], flowinfo [f], scope [s]
1116 * - '[Ii][4S][hnbl]' IPv4 addresses in host, network, big or little endian order
1117 * - 'I[6S]c' for IPv6 addresses printed as specified by
1118 * http://tools.ietf.org/html/rfc5952
1119 * - 'U' For a 16 byte UUID/GUID, it prints the UUID/GUID in the form
1120 * "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
1121 * Options for %pU are:
1122 * b big endian lower case hex (default)
1123 * B big endian UPPER case hex
1124 * l little endian lower case hex
1125 * L little endian UPPER case hex
1126 * big endian output byte order is:
1127 * [0][1][2][3]-[4][5]-[6][7]-[8][9]-[10][11][12][13][14][15]
1128 * little endian output byte order is:
1129 * [3][2][1][0]-[5][4]-[7][6]-[8][9]-[10][11][12][13][14][15]
1130 * - 'V' For a struct va_format which contains a format string * and va_list *,
1131 * call vsnprintf(->format, *->va_list).
1132 * Implements a "recursive vsnprintf".
1133 * Do not use this feature without some mechanism to verify the
1134 * correctness of the format string and va_list arguments.
1135 * - 'K' For a kernel pointer that should be hidden from unprivileged users
1136 * - 'NF' For a netdev_features_t
1137 * - 'h[CDN]' For a variable-length buffer, it prints it as a hex string with
1138 * a certain separator (' ' by default):
1139 * C colon
1140 * D dash
1141 * N no separator
1142 * The maximum supported length is 64 bytes of the input. Consider
1143 * to use print_hex_dump() for the larger input.
1144 * - 'a' For a phys_addr_t type and its derivative types (passed by reference)
1146 * Note: The difference between 'S' and 'F' is that on ia64 and ppc64
1147 * function pointers are really function descriptors, which contain a
1148 * pointer to the real address.
1150 static noinline_for_stack
1151 char *pointer(const char *fmt, char *buf, char *end, void *ptr,
1152 struct printf_spec spec)
1154 int default_width = 2 * sizeof(void *) + (spec.flags & SPECIAL ? 2 : 0);
1156 if (!ptr && *fmt != 'K') {
1158 * Print (null) with the same width as a pointer so it makes
1159 * tabular output look nice.
1161 if (spec.field_width == -1)
1162 spec.field_width = default_width;
1163 return string(buf, end, "(null)", spec);
1166 switch (*fmt) {
1167 case 'F':
1168 case 'f':
1169 ptr = dereference_function_descriptor(ptr);
1170 /* Fallthrough */
1171 case 'S':
1172 case 's':
1173 case 'B':
1174 return symbol_string(buf, end, ptr, spec, fmt);
1175 case 'R':
1176 case 'r':
1177 return resource_string(buf, end, ptr, spec, fmt);
1178 case 'h':
1179 return hex_string(buf, end, ptr, spec, fmt);
1180 case 'M': /* Colon separated: 00:01:02:03:04:05 */
1181 case 'm': /* Contiguous: 000102030405 */
1182 /* [mM]F (FDDI) */
1183 /* [mM]R (Reverse order; Bluetooth) */
1184 return mac_address_string(buf, end, ptr, spec, fmt);
1185 case 'I': /* Formatted IP supported
1186 * 4: 1.2.3.4
1187 * 6: 0001:0203:...:0708
1188 * 6c: 1::708 or 1::1.2.3.4
1190 case 'i': /* Contiguous:
1191 * 4: 001.002.003.004
1192 * 6: 000102...0f
1194 switch (fmt[1]) {
1195 case '6':
1196 return ip6_addr_string(buf, end, ptr, spec, fmt);
1197 case '4':
1198 return ip4_addr_string(buf, end, ptr, spec, fmt);
1199 case 'S': {
1200 const union {
1201 struct sockaddr raw;
1202 struct sockaddr_in v4;
1203 struct sockaddr_in6 v6;
1204 } *sa = ptr;
1206 switch (sa->raw.sa_family) {
1207 case AF_INET:
1208 return ip4_addr_string_sa(buf, end, &sa->v4, spec, fmt);
1209 case AF_INET6:
1210 return ip6_addr_string_sa(buf, end, &sa->v6, spec, fmt);
1211 default:
1212 return string(buf, end, "(invalid address)", spec);
1215 break;
1216 case 'U':
1217 return uuid_string(buf, end, ptr, spec, fmt);
1218 case 'V':
1220 va_list va;
1222 va_copy(va, *((struct va_format *)ptr)->va);
1223 buf += vsnprintf(buf, end > buf ? end - buf : 0,
1224 ((struct va_format *)ptr)->fmt, va);
1225 va_end(va);
1226 return buf;
1228 case 'K':
1230 * %pK cannot be used in IRQ context because its test
1231 * for CAP_SYSLOG would be meaningless.
1233 if (kptr_restrict && (in_irq() || in_serving_softirq() ||
1234 in_nmi())) {
1235 if (spec.field_width == -1)
1236 spec.field_width = default_width;
1237 return string(buf, end, "pK-error", spec);
1239 if (!((kptr_restrict == 0) ||
1240 (kptr_restrict == 1 &&
1241 has_capability_noaudit(current, CAP_SYSLOG))))
1242 ptr = NULL;
1243 break;
1244 case 'N':
1245 switch (fmt[1]) {
1246 case 'F':
1247 return netdev_feature_string(buf, end, ptr, spec);
1249 break;
1250 case 'a':
1251 spec.flags |= SPECIAL | SMALL | ZEROPAD;
1252 spec.field_width = sizeof(phys_addr_t) * 2 + 2;
1253 spec.base = 16;
1254 return number(buf, end,
1255 (unsigned long long) *((phys_addr_t *)ptr), spec);
1257 spec.flags |= SMALL;
1258 if (spec.field_width == -1) {
1259 spec.field_width = default_width;
1260 spec.flags |= ZEROPAD;
1262 spec.base = 16;
1264 return number(buf, end, (unsigned long) ptr, spec);
1268 * Helper function to decode printf style format.
1269 * Each call decode a token from the format and return the
1270 * number of characters read (or likely the delta where it wants
1271 * to go on the next call).
1272 * The decoded token is returned through the parameters
1274 * 'h', 'l', or 'L' for integer fields
1275 * 'z' support added 23/7/1999 S.H.
1276 * 'z' changed to 'Z' --davidm 1/25/99
1277 * 't' added for ptrdiff_t
1279 * @fmt: the format string
1280 * @type of the token returned
1281 * @flags: various flags such as +, -, # tokens..
1282 * @field_width: overwritten width
1283 * @base: base of the number (octal, hex, ...)
1284 * @precision: precision of a number
1285 * @qualifier: qualifier of a number (long, size_t, ...)
1287 static noinline_for_stack
1288 int format_decode(const char *fmt, struct printf_spec *spec)
1290 const char *start = fmt;
1292 /* we finished early by reading the field width */
1293 if (spec->type == FORMAT_TYPE_WIDTH) {
1294 if (spec->field_width < 0) {
1295 spec->field_width = -spec->field_width;
1296 spec->flags |= LEFT;
1298 spec->type = FORMAT_TYPE_NONE;
1299 goto precision;
1302 /* we finished early by reading the precision */
1303 if (spec->type == FORMAT_TYPE_PRECISION) {
1304 if (spec->precision < 0)
1305 spec->precision = 0;
1307 spec->type = FORMAT_TYPE_NONE;
1308 goto qualifier;
1311 /* By default */
1312 spec->type = FORMAT_TYPE_NONE;
1314 for (; *fmt ; ++fmt) {
1315 if (*fmt == '%')
1316 break;
1319 /* Return the current non-format string */
1320 if (fmt != start || !*fmt)
1321 return fmt - start;
1323 /* Process flags */
1324 spec->flags = 0;
1326 while (1) { /* this also skips first '%' */
1327 bool found = true;
1329 ++fmt;
1331 switch (*fmt) {
1332 case '-': spec->flags |= LEFT; break;
1333 case '+': spec->flags |= PLUS; break;
1334 case ' ': spec->flags |= SPACE; break;
1335 case '#': spec->flags |= SPECIAL; break;
1336 case '0': spec->flags |= ZEROPAD; break;
1337 default: found = false;
1340 if (!found)
1341 break;
1344 /* get field width */
1345 spec->field_width = -1;
1347 if (isdigit(*fmt))
1348 spec->field_width = skip_atoi(&fmt);
1349 else if (*fmt == '*') {
1350 /* it's the next argument */
1351 spec->type = FORMAT_TYPE_WIDTH;
1352 return ++fmt - start;
1355 precision:
1356 /* get the precision */
1357 spec->precision = -1;
1358 if (*fmt == '.') {
1359 ++fmt;
1360 if (isdigit(*fmt)) {
1361 spec->precision = skip_atoi(&fmt);
1362 if (spec->precision < 0)
1363 spec->precision = 0;
1364 } else if (*fmt == '*') {
1365 /* it's the next argument */
1366 spec->type = FORMAT_TYPE_PRECISION;
1367 return ++fmt - start;
1371 qualifier:
1372 /* get the conversion qualifier */
1373 spec->qualifier = -1;
1374 if (*fmt == 'h' || _tolower(*fmt) == 'l' ||
1375 _tolower(*fmt) == 'z' || *fmt == 't') {
1376 spec->qualifier = *fmt++;
1377 if (unlikely(spec->qualifier == *fmt)) {
1378 if (spec->qualifier == 'l') {
1379 spec->qualifier = 'L';
1380 ++fmt;
1381 } else if (spec->qualifier == 'h') {
1382 spec->qualifier = 'H';
1383 ++fmt;
1388 /* default base */
1389 spec->base = 10;
1390 switch (*fmt) {
1391 case 'c':
1392 spec->type = FORMAT_TYPE_CHAR;
1393 return ++fmt - start;
1395 case 's':
1396 spec->type = FORMAT_TYPE_STR;
1397 return ++fmt - start;
1399 case 'p':
1400 spec->type = FORMAT_TYPE_PTR;
1401 return fmt - start;
1402 /* skip alnum */
1404 case 'n':
1405 spec->type = FORMAT_TYPE_NRCHARS;
1406 return ++fmt - start;
1408 case '%':
1409 spec->type = FORMAT_TYPE_PERCENT_CHAR;
1410 return ++fmt - start;
1412 /* integer number formats - set up the flags and "break" */
1413 case 'o':
1414 spec->base = 8;
1415 break;
1417 case 'x':
1418 spec->flags |= SMALL;
1420 case 'X':
1421 spec->base = 16;
1422 break;
1424 case 'd':
1425 case 'i':
1426 spec->flags |= SIGN;
1427 case 'u':
1428 break;
1430 default:
1431 spec->type = FORMAT_TYPE_INVALID;
1432 return fmt - start;
1435 if (spec->qualifier == 'L')
1436 spec->type = FORMAT_TYPE_LONG_LONG;
1437 else if (spec->qualifier == 'l') {
1438 if (spec->flags & SIGN)
1439 spec->type = FORMAT_TYPE_LONG;
1440 else
1441 spec->type = FORMAT_TYPE_ULONG;
1442 } else if (_tolower(spec->qualifier) == 'z') {
1443 spec->type = FORMAT_TYPE_SIZE_T;
1444 } else if (spec->qualifier == 't') {
1445 spec->type = FORMAT_TYPE_PTRDIFF;
1446 } else if (spec->qualifier == 'H') {
1447 if (spec->flags & SIGN)
1448 spec->type = FORMAT_TYPE_BYTE;
1449 else
1450 spec->type = FORMAT_TYPE_UBYTE;
1451 } else if (spec->qualifier == 'h') {
1452 if (spec->flags & SIGN)
1453 spec->type = FORMAT_TYPE_SHORT;
1454 else
1455 spec->type = FORMAT_TYPE_USHORT;
1456 } else {
1457 if (spec->flags & SIGN)
1458 spec->type = FORMAT_TYPE_INT;
1459 else
1460 spec->type = FORMAT_TYPE_UINT;
1463 return ++fmt - start;
1467 * vsnprintf - Format a string and place it in a buffer
1468 * @buf: The buffer to place the result into
1469 * @size: The size of the buffer, including the trailing null space
1470 * @fmt: The format string to use
1471 * @args: Arguments for the format string
1473 * This function follows C99 vsnprintf, but has some extensions:
1474 * %pS output the name of a text symbol with offset
1475 * %ps output the name of a text symbol without offset
1476 * %pF output the name of a function pointer with its offset
1477 * %pf output the name of a function pointer without its offset
1478 * %pB output the name of a backtrace symbol with its offset
1479 * %pR output the address range in a struct resource with decoded flags
1480 * %pr output the address range in a struct resource with raw flags
1481 * %pM output a 6-byte MAC address with colons
1482 * %pMR output a 6-byte MAC address with colons in reversed order
1483 * %pMF output a 6-byte MAC address with dashes
1484 * %pm output a 6-byte MAC address without colons
1485 * %pmR output a 6-byte MAC address without colons in reversed order
1486 * %pI4 print an IPv4 address without leading zeros
1487 * %pi4 print an IPv4 address with leading zeros
1488 * %pI6 print an IPv6 address with colons
1489 * %pi6 print an IPv6 address without colons
1490 * %pI6c print an IPv6 address as specified by RFC 5952
1491 * %pIS depending on sa_family of 'struct sockaddr *' print IPv4/IPv6 address
1492 * %piS depending on sa_family of 'struct sockaddr *' print IPv4/IPv6 address
1493 * %pU[bBlL] print a UUID/GUID in big or little endian using lower or upper
1494 * case.
1495 * %*ph[CDN] a variable-length hex string with a separator (supports up to 64
1496 * bytes of the input)
1497 * %n is ignored
1499 * ** Please update Documentation/printk-formats.txt when making changes **
1501 * The return value is the number of characters which would
1502 * be generated for the given input, excluding the trailing
1503 * '\0', as per ISO C99. If you want to have the exact
1504 * number of characters written into @buf as return value
1505 * (not including the trailing '\0'), use vscnprintf(). If the
1506 * return is greater than or equal to @size, the resulting
1507 * string is truncated.
1509 * If you're not already dealing with a va_list consider using snprintf().
1511 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
1513 unsigned long long num;
1514 char *str, *end;
1515 struct printf_spec spec = {0};
1517 /* Reject out-of-range values early. Large positive sizes are
1518 used for unknown buffer sizes. */
1519 if (WARN_ON_ONCE((int) size < 0))
1520 return 0;
1522 str = buf;
1523 end = buf + size;
1525 /* Make sure end is always >= buf */
1526 if (end < buf) {
1527 end = ((void *)-1);
1528 size = end - buf;
1531 while (*fmt) {
1532 const char *old_fmt = fmt;
1533 int read = format_decode(fmt, &spec);
1535 fmt += read;
1537 switch (spec.type) {
1538 case FORMAT_TYPE_NONE: {
1539 int copy = read;
1540 if (str < end) {
1541 if (copy > end - str)
1542 copy = end - str;
1543 memcpy(str, old_fmt, copy);
1545 str += read;
1546 break;
1549 case FORMAT_TYPE_WIDTH:
1550 spec.field_width = va_arg(args, int);
1551 break;
1553 case FORMAT_TYPE_PRECISION:
1554 spec.precision = va_arg(args, int);
1555 break;
1557 case FORMAT_TYPE_CHAR: {
1558 char c;
1560 if (!(spec.flags & LEFT)) {
1561 while (--spec.field_width > 0) {
1562 if (str < end)
1563 *str = ' ';
1564 ++str;
1568 c = (unsigned char) va_arg(args, int);
1569 if (str < end)
1570 *str = c;
1571 ++str;
1572 while (--spec.field_width > 0) {
1573 if (str < end)
1574 *str = ' ';
1575 ++str;
1577 break;
1580 case FORMAT_TYPE_STR:
1581 str = string(str, end, va_arg(args, char *), spec);
1582 break;
1584 case FORMAT_TYPE_PTR:
1585 str = pointer(fmt+1, str, end, va_arg(args, void *),
1586 spec);
1587 while (isalnum(*fmt))
1588 fmt++;
1589 break;
1591 case FORMAT_TYPE_PERCENT_CHAR:
1592 if (str < end)
1593 *str = '%';
1594 ++str;
1595 break;
1597 case FORMAT_TYPE_INVALID:
1598 if (str < end)
1599 *str = '%';
1600 ++str;
1601 break;
1603 case FORMAT_TYPE_NRCHARS: {
1604 u8 qualifier = spec.qualifier;
1606 if (qualifier == 'l') {
1607 long *ip = va_arg(args, long *);
1608 *ip = (str - buf);
1609 } else if (_tolower(qualifier) == 'z') {
1610 size_t *ip = va_arg(args, size_t *);
1611 *ip = (str - buf);
1612 } else {
1613 int *ip = va_arg(args, int *);
1614 *ip = (str - buf);
1616 break;
1619 default:
1620 switch (spec.type) {
1621 case FORMAT_TYPE_LONG_LONG:
1622 num = va_arg(args, long long);
1623 break;
1624 case FORMAT_TYPE_ULONG:
1625 num = va_arg(args, unsigned long);
1626 break;
1627 case FORMAT_TYPE_LONG:
1628 num = va_arg(args, long);
1629 break;
1630 case FORMAT_TYPE_SIZE_T:
1631 if (spec.flags & SIGN)
1632 num = va_arg(args, ssize_t);
1633 else
1634 num = va_arg(args, size_t);
1635 break;
1636 case FORMAT_TYPE_PTRDIFF:
1637 num = va_arg(args, ptrdiff_t);
1638 break;
1639 case FORMAT_TYPE_UBYTE:
1640 num = (unsigned char) va_arg(args, int);
1641 break;
1642 case FORMAT_TYPE_BYTE:
1643 num = (signed char) va_arg(args, int);
1644 break;
1645 case FORMAT_TYPE_USHORT:
1646 num = (unsigned short) va_arg(args, int);
1647 break;
1648 case FORMAT_TYPE_SHORT:
1649 num = (short) va_arg(args, int);
1650 break;
1651 case FORMAT_TYPE_INT:
1652 num = (int) va_arg(args, int);
1653 break;
1654 default:
1655 num = va_arg(args, unsigned int);
1658 str = number(str, end, num, spec);
1662 if (size > 0) {
1663 if (str < end)
1664 *str = '\0';
1665 else
1666 end[-1] = '\0';
1669 /* the trailing null byte doesn't count towards the total */
1670 return str-buf;
1673 EXPORT_SYMBOL(vsnprintf);
1676 * vscnprintf - Format a string and place it in a buffer
1677 * @buf: The buffer to place the result into
1678 * @size: The size of the buffer, including the trailing null space
1679 * @fmt: The format string to use
1680 * @args: Arguments for the format string
1682 * The return value is the number of characters which have been written into
1683 * the @buf not including the trailing '\0'. If @size is == 0 the function
1684 * returns 0.
1686 * If you're not already dealing with a va_list consider using scnprintf().
1688 * See the vsnprintf() documentation for format string extensions over C99.
1690 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
1692 int i;
1694 i = vsnprintf(buf, size, fmt, args);
1696 if (likely(i < size))
1697 return i;
1698 if (size != 0)
1699 return size - 1;
1700 return 0;
1702 EXPORT_SYMBOL(vscnprintf);
1705 * snprintf - Format a string and place it in a buffer
1706 * @buf: The buffer to place the result into
1707 * @size: The size of the buffer, including the trailing null space
1708 * @fmt: The format string to use
1709 * @...: Arguments for the format string
1711 * The return value is the number of characters which would be
1712 * generated for the given input, excluding the trailing null,
1713 * as per ISO C99. If the return is greater than or equal to
1714 * @size, the resulting string is truncated.
1716 * See the vsnprintf() documentation for format string extensions over C99.
1718 int snprintf(char *buf, size_t size, const char *fmt, ...)
1720 va_list args;
1721 int i;
1723 va_start(args, fmt);
1724 i = vsnprintf(buf, size, fmt, args);
1725 va_end(args);
1727 return i;
1729 EXPORT_SYMBOL(snprintf);
1732 * scnprintf - Format a string and place it in a buffer
1733 * @buf: The buffer to place the result into
1734 * @size: The size of the buffer, including the trailing null space
1735 * @fmt: The format string to use
1736 * @...: Arguments for the format string
1738 * The return value is the number of characters written into @buf not including
1739 * the trailing '\0'. If @size is == 0 the function returns 0.
1742 int scnprintf(char *buf, size_t size, const char *fmt, ...)
1744 va_list args;
1745 int i;
1747 va_start(args, fmt);
1748 i = vscnprintf(buf, size, fmt, args);
1749 va_end(args);
1751 return i;
1753 EXPORT_SYMBOL(scnprintf);
1756 * vsprintf - Format a string and place it in a buffer
1757 * @buf: The buffer to place the result into
1758 * @fmt: The format string to use
1759 * @args: Arguments for the format string
1761 * The function returns the number of characters written
1762 * into @buf. Use vsnprintf() or vscnprintf() in order to avoid
1763 * buffer overflows.
1765 * If you're not already dealing with a va_list consider using sprintf().
1767 * See the vsnprintf() documentation for format string extensions over C99.
1769 int vsprintf(char *buf, const char *fmt, va_list args)
1771 return vsnprintf(buf, INT_MAX, fmt, args);
1773 EXPORT_SYMBOL(vsprintf);
1776 * sprintf - Format a string and place it in a buffer
1777 * @buf: The buffer to place the result into
1778 * @fmt: The format string to use
1779 * @...: Arguments for the format string
1781 * The function returns the number of characters written
1782 * into @buf. Use snprintf() or scnprintf() in order to avoid
1783 * buffer overflows.
1785 * See the vsnprintf() documentation for format string extensions over C99.
1787 int sprintf(char *buf, const char *fmt, ...)
1789 va_list args;
1790 int i;
1792 va_start(args, fmt);
1793 i = vsnprintf(buf, INT_MAX, fmt, args);
1794 va_end(args);
1796 return i;
1798 EXPORT_SYMBOL(sprintf);
1800 #ifdef CONFIG_BINARY_PRINTF
1802 * bprintf service:
1803 * vbin_printf() - VA arguments to binary data
1804 * bstr_printf() - Binary data to text string
1808 * vbin_printf - Parse a format string and place args' binary value in a buffer
1809 * @bin_buf: The buffer to place args' binary value
1810 * @size: The size of the buffer(by words(32bits), not characters)
1811 * @fmt: The format string to use
1812 * @args: Arguments for the format string
1814 * The format follows C99 vsnprintf, except %n is ignored, and its argument
1815 * is skiped.
1817 * The return value is the number of words(32bits) which would be generated for
1818 * the given input.
1820 * NOTE:
1821 * If the return value is greater than @size, the resulting bin_buf is NOT
1822 * valid for bstr_printf().
1824 int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args)
1826 struct printf_spec spec = {0};
1827 char *str, *end;
1829 str = (char *)bin_buf;
1830 end = (char *)(bin_buf + size);
1832 #define save_arg(type) \
1833 do { \
1834 if (sizeof(type) == 8) { \
1835 unsigned long long value; \
1836 str = PTR_ALIGN(str, sizeof(u32)); \
1837 value = va_arg(args, unsigned long long); \
1838 if (str + sizeof(type) <= end) { \
1839 *(u32 *)str = *(u32 *)&value; \
1840 *(u32 *)(str + 4) = *((u32 *)&value + 1); \
1842 } else { \
1843 unsigned long value; \
1844 str = PTR_ALIGN(str, sizeof(type)); \
1845 value = va_arg(args, int); \
1846 if (str + sizeof(type) <= end) \
1847 *(typeof(type) *)str = (type)value; \
1849 str += sizeof(type); \
1850 } while (0)
1852 while (*fmt) {
1853 int read = format_decode(fmt, &spec);
1855 fmt += read;
1857 switch (spec.type) {
1858 case FORMAT_TYPE_NONE:
1859 case FORMAT_TYPE_INVALID:
1860 case FORMAT_TYPE_PERCENT_CHAR:
1861 break;
1863 case FORMAT_TYPE_WIDTH:
1864 case FORMAT_TYPE_PRECISION:
1865 save_arg(int);
1866 break;
1868 case FORMAT_TYPE_CHAR:
1869 save_arg(char);
1870 break;
1872 case FORMAT_TYPE_STR: {
1873 const char *save_str = va_arg(args, char *);
1874 size_t len;
1876 if ((unsigned long)save_str > (unsigned long)-PAGE_SIZE
1877 || (unsigned long)save_str < PAGE_SIZE)
1878 save_str = "(null)";
1879 len = strlen(save_str) + 1;
1880 if (str + len < end)
1881 memcpy(str, save_str, len);
1882 str += len;
1883 break;
1886 case FORMAT_TYPE_PTR:
1887 save_arg(void *);
1888 /* skip all alphanumeric pointer suffixes */
1889 while (isalnum(*fmt))
1890 fmt++;
1891 break;
1893 case FORMAT_TYPE_NRCHARS: {
1894 /* skip %n 's argument */
1895 u8 qualifier = spec.qualifier;
1896 void *skip_arg;
1897 if (qualifier == 'l')
1898 skip_arg = va_arg(args, long *);
1899 else if (_tolower(qualifier) == 'z')
1900 skip_arg = va_arg(args, size_t *);
1901 else
1902 skip_arg = va_arg(args, int *);
1903 break;
1906 default:
1907 switch (spec.type) {
1909 case FORMAT_TYPE_LONG_LONG:
1910 save_arg(long long);
1911 break;
1912 case FORMAT_TYPE_ULONG:
1913 case FORMAT_TYPE_LONG:
1914 save_arg(unsigned long);
1915 break;
1916 case FORMAT_TYPE_SIZE_T:
1917 save_arg(size_t);
1918 break;
1919 case FORMAT_TYPE_PTRDIFF:
1920 save_arg(ptrdiff_t);
1921 break;
1922 case FORMAT_TYPE_UBYTE:
1923 case FORMAT_TYPE_BYTE:
1924 save_arg(char);
1925 break;
1926 case FORMAT_TYPE_USHORT:
1927 case FORMAT_TYPE_SHORT:
1928 save_arg(short);
1929 break;
1930 default:
1931 save_arg(int);
1936 return (u32 *)(PTR_ALIGN(str, sizeof(u32))) - bin_buf;
1937 #undef save_arg
1939 EXPORT_SYMBOL_GPL(vbin_printf);
1942 * bstr_printf - Format a string from binary arguments and place it in a buffer
1943 * @buf: The buffer to place the result into
1944 * @size: The size of the buffer, including the trailing null space
1945 * @fmt: The format string to use
1946 * @bin_buf: Binary arguments for the format string
1948 * This function like C99 vsnprintf, but the difference is that vsnprintf gets
1949 * arguments from stack, and bstr_printf gets arguments from @bin_buf which is
1950 * a binary buffer that generated by vbin_printf.
1952 * The format follows C99 vsnprintf, but has some extensions:
1953 * see vsnprintf comment for details.
1955 * The return value is the number of characters which would
1956 * be generated for the given input, excluding the trailing
1957 * '\0', as per ISO C99. If you want to have the exact
1958 * number of characters written into @buf as return value
1959 * (not including the trailing '\0'), use vscnprintf(). If the
1960 * return is greater than or equal to @size, the resulting
1961 * string is truncated.
1963 int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf)
1965 struct printf_spec spec = {0};
1966 char *str, *end;
1967 const char *args = (const char *)bin_buf;
1969 if (WARN_ON_ONCE((int) size < 0))
1970 return 0;
1972 str = buf;
1973 end = buf + size;
1975 #define get_arg(type) \
1976 ({ \
1977 typeof(type) value; \
1978 if (sizeof(type) == 8) { \
1979 args = PTR_ALIGN(args, sizeof(u32)); \
1980 *(u32 *)&value = *(u32 *)args; \
1981 *((u32 *)&value + 1) = *(u32 *)(args + 4); \
1982 } else { \
1983 args = PTR_ALIGN(args, sizeof(type)); \
1984 value = *(typeof(type) *)args; \
1986 args += sizeof(type); \
1987 value; \
1990 /* Make sure end is always >= buf */
1991 if (end < buf) {
1992 end = ((void *)-1);
1993 size = end - buf;
1996 while (*fmt) {
1997 const char *old_fmt = fmt;
1998 int read = format_decode(fmt, &spec);
2000 fmt += read;
2002 switch (spec.type) {
2003 case FORMAT_TYPE_NONE: {
2004 int copy = read;
2005 if (str < end) {
2006 if (copy > end - str)
2007 copy = end - str;
2008 memcpy(str, old_fmt, copy);
2010 str += read;
2011 break;
2014 case FORMAT_TYPE_WIDTH:
2015 spec.field_width = get_arg(int);
2016 break;
2018 case FORMAT_TYPE_PRECISION:
2019 spec.precision = get_arg(int);
2020 break;
2022 case FORMAT_TYPE_CHAR: {
2023 char c;
2025 if (!(spec.flags & LEFT)) {
2026 while (--spec.field_width > 0) {
2027 if (str < end)
2028 *str = ' ';
2029 ++str;
2032 c = (unsigned char) get_arg(char);
2033 if (str < end)
2034 *str = c;
2035 ++str;
2036 while (--spec.field_width > 0) {
2037 if (str < end)
2038 *str = ' ';
2039 ++str;
2041 break;
2044 case FORMAT_TYPE_STR: {
2045 const char *str_arg = args;
2046 args += strlen(str_arg) + 1;
2047 str = string(str, end, (char *)str_arg, spec);
2048 break;
2051 case FORMAT_TYPE_PTR:
2052 str = pointer(fmt+1, str, end, get_arg(void *), spec);
2053 while (isalnum(*fmt))
2054 fmt++;
2055 break;
2057 case FORMAT_TYPE_PERCENT_CHAR:
2058 case FORMAT_TYPE_INVALID:
2059 if (str < end)
2060 *str = '%';
2061 ++str;
2062 break;
2064 case FORMAT_TYPE_NRCHARS:
2065 /* skip */
2066 break;
2068 default: {
2069 unsigned long long num;
2071 switch (spec.type) {
2073 case FORMAT_TYPE_LONG_LONG:
2074 num = get_arg(long long);
2075 break;
2076 case FORMAT_TYPE_ULONG:
2077 case FORMAT_TYPE_LONG:
2078 num = get_arg(unsigned long);
2079 break;
2080 case FORMAT_TYPE_SIZE_T:
2081 num = get_arg(size_t);
2082 break;
2083 case FORMAT_TYPE_PTRDIFF:
2084 num = get_arg(ptrdiff_t);
2085 break;
2086 case FORMAT_TYPE_UBYTE:
2087 num = get_arg(unsigned char);
2088 break;
2089 case FORMAT_TYPE_BYTE:
2090 num = get_arg(signed char);
2091 break;
2092 case FORMAT_TYPE_USHORT:
2093 num = get_arg(unsigned short);
2094 break;
2095 case FORMAT_TYPE_SHORT:
2096 num = get_arg(short);
2097 break;
2098 case FORMAT_TYPE_UINT:
2099 num = get_arg(unsigned int);
2100 break;
2101 default:
2102 num = get_arg(int);
2105 str = number(str, end, num, spec);
2106 } /* default: */
2107 } /* switch(spec.type) */
2108 } /* while(*fmt) */
2110 if (size > 0) {
2111 if (str < end)
2112 *str = '\0';
2113 else
2114 end[-1] = '\0';
2117 #undef get_arg
2119 /* the trailing null byte doesn't count towards the total */
2120 return str - buf;
2122 EXPORT_SYMBOL_GPL(bstr_printf);
2125 * bprintf - Parse a format string and place args' binary value in a buffer
2126 * @bin_buf: The buffer to place args' binary value
2127 * @size: The size of the buffer(by words(32bits), not characters)
2128 * @fmt: The format string to use
2129 * @...: Arguments for the format string
2131 * The function returns the number of words(u32) written
2132 * into @bin_buf.
2134 int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...)
2136 va_list args;
2137 int ret;
2139 va_start(args, fmt);
2140 ret = vbin_printf(bin_buf, size, fmt, args);
2141 va_end(args);
2143 return ret;
2145 EXPORT_SYMBOL_GPL(bprintf);
2147 #endif /* CONFIG_BINARY_PRINTF */
2150 * vsscanf - Unformat a buffer into a list of arguments
2151 * @buf: input buffer
2152 * @fmt: format of buffer
2153 * @args: arguments
2155 int vsscanf(const char *buf, const char *fmt, va_list args)
2157 const char *str = buf;
2158 char *next;
2159 char digit;
2160 int num = 0;
2161 u8 qualifier;
2162 unsigned int base;
2163 union {
2164 long long s;
2165 unsigned long long u;
2166 } val;
2167 s16 field_width;
2168 bool is_sign;
2170 while (*fmt) {
2171 /* skip any white space in format */
2172 /* white space in format matchs any amount of
2173 * white space, including none, in the input.
2175 if (isspace(*fmt)) {
2176 fmt = skip_spaces(++fmt);
2177 str = skip_spaces(str);
2180 /* anything that is not a conversion must match exactly */
2181 if (*fmt != '%' && *fmt) {
2182 if (*fmt++ != *str++)
2183 break;
2184 continue;
2187 if (!*fmt)
2188 break;
2189 ++fmt;
2191 /* skip this conversion.
2192 * advance both strings to next white space
2194 if (*fmt == '*') {
2195 if (!*str)
2196 break;
2197 while (!isspace(*fmt) && *fmt != '%' && *fmt)
2198 fmt++;
2199 while (!isspace(*str) && *str)
2200 str++;
2201 continue;
2204 /* get field width */
2205 field_width = -1;
2206 if (isdigit(*fmt)) {
2207 field_width = skip_atoi(&fmt);
2208 if (field_width <= 0)
2209 break;
2212 /* get conversion qualifier */
2213 qualifier = -1;
2214 if (*fmt == 'h' || _tolower(*fmt) == 'l' ||
2215 _tolower(*fmt) == 'z') {
2216 qualifier = *fmt++;
2217 if (unlikely(qualifier == *fmt)) {
2218 if (qualifier == 'h') {
2219 qualifier = 'H';
2220 fmt++;
2221 } else if (qualifier == 'l') {
2222 qualifier = 'L';
2223 fmt++;
2228 if (!*fmt)
2229 break;
2231 if (*fmt == 'n') {
2232 /* return number of characters read so far */
2233 *va_arg(args, int *) = str - buf;
2234 ++fmt;
2235 continue;
2238 if (!*str)
2239 break;
2241 base = 10;
2242 is_sign = 0;
2244 switch (*fmt++) {
2245 case 'c':
2247 char *s = (char *)va_arg(args, char*);
2248 if (field_width == -1)
2249 field_width = 1;
2250 do {
2251 *s++ = *str++;
2252 } while (--field_width > 0 && *str);
2253 num++;
2255 continue;
2256 case 's':
2258 char *s = (char *)va_arg(args, char *);
2259 if (field_width == -1)
2260 field_width = SHRT_MAX;
2261 /* first, skip leading white space in buffer */
2262 str = skip_spaces(str);
2264 /* now copy until next white space */
2265 while (*str && !isspace(*str) && field_width--)
2266 *s++ = *str++;
2267 *s = '\0';
2268 num++;
2270 continue;
2271 case 'o':
2272 base = 8;
2273 break;
2274 case 'x':
2275 case 'X':
2276 base = 16;
2277 break;
2278 case 'i':
2279 base = 0;
2280 case 'd':
2281 is_sign = 1;
2282 case 'u':
2283 break;
2284 case '%':
2285 /* looking for '%' in str */
2286 if (*str++ != '%')
2287 return num;
2288 continue;
2289 default:
2290 /* invalid format; stop here */
2291 return num;
2294 /* have some sort of integer conversion.
2295 * first, skip white space in buffer.
2297 str = skip_spaces(str);
2299 digit = *str;
2300 if (is_sign && digit == '-')
2301 digit = *(str + 1);
2303 if (!digit
2304 || (base == 16 && !isxdigit(digit))
2305 || (base == 10 && !isdigit(digit))
2306 || (base == 8 && (!isdigit(digit) || digit > '7'))
2307 || (base == 0 && !isdigit(digit)))
2308 break;
2310 if (is_sign)
2311 val.s = qualifier != 'L' ?
2312 simple_strtol(str, &next, base) :
2313 simple_strtoll(str, &next, base);
2314 else
2315 val.u = qualifier != 'L' ?
2316 simple_strtoul(str, &next, base) :
2317 simple_strtoull(str, &next, base);
2319 if (field_width > 0 && next - str > field_width) {
2320 if (base == 0)
2321 _parse_integer_fixup_radix(str, &base);
2322 while (next - str > field_width) {
2323 if (is_sign)
2324 val.s = div_s64(val.s, base);
2325 else
2326 val.u = div_u64(val.u, base);
2327 --next;
2331 switch (qualifier) {
2332 case 'H': /* that's 'hh' in format */
2333 if (is_sign)
2334 *va_arg(args, signed char *) = val.s;
2335 else
2336 *va_arg(args, unsigned char *) = val.u;
2337 break;
2338 case 'h':
2339 if (is_sign)
2340 *va_arg(args, short *) = val.s;
2341 else
2342 *va_arg(args, unsigned short *) = val.u;
2343 break;
2344 case 'l':
2345 if (is_sign)
2346 *va_arg(args, long *) = val.s;
2347 else
2348 *va_arg(args, unsigned long *) = val.u;
2349 break;
2350 case 'L':
2351 if (is_sign)
2352 *va_arg(args, long long *) = val.s;
2353 else
2354 *va_arg(args, unsigned long long *) = val.u;
2355 break;
2356 case 'Z':
2357 case 'z':
2358 *va_arg(args, size_t *) = val.u;
2359 break;
2360 default:
2361 if (is_sign)
2362 *va_arg(args, int *) = val.s;
2363 else
2364 *va_arg(args, unsigned int *) = val.u;
2365 break;
2367 num++;
2369 if (!next)
2370 break;
2371 str = next;
2374 return num;
2376 EXPORT_SYMBOL(vsscanf);
2379 * sscanf - Unformat a buffer into a list of arguments
2380 * @buf: input buffer
2381 * @fmt: formatting of buffer
2382 * @...: resulting arguments
2384 int sscanf(const char *buf, const char *fmt, ...)
2386 va_list args;
2387 int i;
2389 va_start(args, fmt);
2390 i = vsscanf(buf, fmt, args);
2391 va_end(args);
2393 return i;
2395 EXPORT_SYMBOL(sscanf);