cregit-Linux how code gets into the kernel

Release 4.7 lib/vsprintf.c

Directory: lib
/*
 *  linux/lib/vsprintf.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 */

/* vsprintf.c -- Lars Wirzenius & Linus Torvalds. */
/*
 * Wirzenius wrote this portably, Torvalds fucked it up :-)
 */

/*
 * Fri Jul 13 2001 Crutcher Dunnavant <crutcher+kernel@datastacks.com>
 * - changed to provide snprintf and vsnprintf functions
 * So Feb  1 16:51:32 CET 2004 Juergen Quade <quade@hsnr.de>
 * - scnprintf and vscnprintf
 */

#include <stdarg.h>
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/module.h>	/* for KSYM_SYMBOL_LEN */
#include <linux/types.h>
#include <linux/string.h>
#include <linux/ctype.h>
#include <linux/kernel.h>
#include <linux/kallsyms.h>
#include <linux/math64.h>
#include <linux/uaccess.h>
#include <linux/ioport.h>
#include <linux/dcache.h>
#include <linux/cred.h>
#include <linux/uuid.h>
#include <net/addrconf.h>
#ifdef CONFIG_BLOCK
#include <linux/blkdev.h>
#endif

#include "../mm/internal.h"	/* For the trace_print_flags arrays */

#include <asm/page.h>		/* for PAGE_SIZE */
#include <asm/sections.h>	/* for dereference_function_descriptor() */
#include <asm/byteorder.h>	/* cpu_to_le16 */

#include <linux/string_helpers.h>
#include "kstrtox.h"

/**
 * simple_strtoull - convert a string to an unsigned long long
 * @cp: The start of the string
 * @endp: A pointer to the end of the parsed string will be placed here
 * @base: The number base to use
 *
 * This function is obsolete. Please use kstrtoull instead.
 */

unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base) { unsigned long long result; unsigned int rv; cp = _parse_integer_fixup_radix(cp, &base); rv = _parse_integer(cp, base, &result); /* FIXME */ cp += (rv & ~KSTRTOX_OVERFLOW); if (endp) *endp = (char *)cp; return result; }

Contributors

PersonTokensPropCommitsCommitProp
pre-gitpre-git5064.10%125.00%
alexey dobriyanalexey dobriyan2228.21%125.00%
andre goddard rosaandre goddard rosa33.85%125.00%
harvey harrisonharvey harrison33.85%125.00%
Total78100.00%4100.00%

EXPORT_SYMBOL(simple_strtoull); /** * simple_strtoul - convert a string to an unsigned long * @cp: The start of the string * @endp: A pointer to the end of the parsed string will be placed here * @base: The number base to use * * This function is obsolete. Please use kstrtoul instead. */
unsigned long simple_strtoul(const char *cp, char **endp, unsigned int base) { return simple_strtoull(cp, endp, base); }

Contributors

PersonTokensPropCommitsCommitProp
pre-gitpre-git2790.00%150.00%
andre goddard rosaandre goddard rosa310.00%150.00%
Total30100.00%2100.00%

EXPORT_SYMBOL(simple_strtoul); /** * simple_strtol - convert a string to a signed long * @cp: The start of the string * @endp: A pointer to the end of the parsed string will be placed here * @base: The number base to use * * This function is obsolete. Please use kstrtol instead. */
long simple_strtol(const char *cp, char **endp, unsigned int base) { if (*cp == '-') return -simple_strtoul(cp + 1, endp, base); return simple_strtoul(cp, endp, base); }

Contributors

PersonTokensPropCommitsCommitProp
pre-gitpre-git2857.14%125.00%
andre goddard rosaandre goddard rosa1836.73%125.00%
chris wrightchris wright24.08%125.00%
harvey harrisonharvey harrison12.04%125.00%
Total49100.00%4100.00%

EXPORT_SYMBOL(simple_strtol); /** * simple_strtoll - convert a string to a signed long long * @cp: The start of the string * @endp: A pointer to the end of the parsed string will be placed here * @base: The number base to use * * This function is obsolete. Please use kstrtoll instead. */
long long simple_strtoll(const char *cp, char **endp, unsigned int base) { if (*cp == '-') return -simple_strtoull(cp + 1, endp, base); return simple_strtoull(cp, endp, base); }

Contributors

PersonTokensPropCommitsCommitProp
pre-gitpre-git50100.00%1100.00%
Total50100.00%1100.00%

EXPORT_SYMBOL(simple_strtoll);
static noinline_for_stack int skip_atoi(const char **s) { int i = 0; do { i = i*10 + *((*s)++) - '0'; } while (isdigit(**s)); return i; }

Contributors

PersonTokensPropCommitsCommitProp
pre-gitpre-git3772.55%133.33%
rasmus villemoesrasmus villemoes1325.49%133.33%
joe perchesjoe perches11.96%133.33%
Total51100.00%3100.00%

/* * Decimal conversion is by far the most typical, and is used for * /proc and /sys data. This directly impacts e.g. top performance * with many processes running. We optimize it for speed by emitting * two characters at a time, using a 200 byte lookup table. This * roughly halves the number of multiplications compared to computing * the digits one at a time. Implementation strongly inspired by the * previous version, which in turn used ideas described at * <http://www.cs.uiowa.edu/~jones/bcd/divide.html> (with permission * from the author, Douglas W. Jones). * * It turns out there is precisely one 26 bit fixed-point * approximation a of 64/100 for which x/100 == (x * (u64)a) >> 32 * holds for all x in [0, 10^8-1], namely a = 0x28f5c29. The actual * range happens to be somewhat larger (x <= 1073741898), but that's * irrelevant for our purpose. * * For dividing a number in the range [10^4, 10^6-1] by 100, we still * need a 32x32->64 bit multiply, so we simply use the same constant. * * For dividing a number in the range [100, 10^4-1] by 100, there are * several options. The simplest is (x * 0x147b) >> 19, which is valid * for all x <= 43698. */ static const u16 decpair[100] = { #define _(x) (__force u16) cpu_to_le16(((x % 10) | ((x / 10) << 8)) + 0x3030) _( 0), _( 1), _( 2), _( 3), _( 4), _( 5), _( 6), _( 7), _( 8), _( 9), _(10), _(11), _(12), _(13), _(14), _(15), _(16), _(17), _(18), _(19), _(20), _(21), _(22), _(23), _(24), _(25), _(26), _(27), _(28), _(29), _(30), _(31), _(32), _(33), _(34), _(35), _(36), _(37), _(38), _(39), _(40), _(41), _(42), _(43), _(44), _(45), _(46), _(47), _(48), _(49), _(50), _(51), _(52), _(53), _(54), _(55), _(56), _(57), _(58), _(59), _(60), _(61), _(62), _(63), _(64), _(65), _(66), _(67), _(68), _(69), _(70), _(71), _(72), _(73), _(74), _(75), _(76), _(77), _(78), _(79), _(80), _(81), _(82), _(83), _(84), _(85), _(86), _(87), _(88), _(89), _(90), _(91), _(92), _(93), _(94), _(95), _(96), _(97), _(98), _(99), #undef _ }; /* * This will print a single '0' even if r == 0, since we would * immediately jump to out_r where two 0s would be written but only * one of them accounted for in buf. This is needed by ip4_string * below. All other callers pass a non-zero value of r. */
static noinline_for_stack char *put_dec_trunc8(char *buf, unsigned r) { unsigned q; /* 1 <= r < 10^8 */ if (r < 100) goto out_r; /* 100 <= r < 10^8 */ q = (r * (u64)0x28f5c29) >> 32; *((u16 *)buf) = decpair[r - 100*q]; buf += 2; /* 1 <= q < 10^6 */ if (q < 100) goto out_q; /* 100 <= q < 10^6 */ r = (q * (u64)0x28f5c29) >> 32; *((u16 *)buf) = decpair[q - 100*r]; buf += 2; /* 1 <= r < 10^4 */ if (r < 100) goto out_r; /* 100 <= r < 10^4 */ q = (r * 0x147b) >> 19; *((u16 *)buf) = decpair[r - 100*q]; buf += 2; out_q: /* 1 <= q < 100 */ r = q; out_r: /* 1 <= r < 100 */ *((u16 *)buf) = decpair[r]; buf += r < 10 ? 1 : 2; return buf; }

Contributors

PersonTokensPropCommitsCommitProp
rasmus villemoesrasmus villemoes16486.32%250.00%
denys vlasenkodenys vlasenko2613.68%250.00%
Total190100.00%4100.00%

#if BITS_PER_LONG == 64 && BITS_PER_LONG_LONG == 64
static noinline_for_stack char *put_dec_full8(char *buf, unsigned r) { unsigned q; /* 0 <= r < 10^8 */ q = (r * (u64)0x28f5c29) >> 32; *((u16 *)buf) = decpair[r - 100*q]; buf += 2; /* 0 <= q < 10^6 */ r = (q * (u64)0x28f5c29) >> 32; *((u16 *)buf) = decpair[q - 100*r]; buf += 2; /* 0 <= r < 10^4 */ q = (r * 0x147b) >> 19; *((u16 *)buf) = decpair[r - 100*q]; buf += 2; /* 0 <= q < 100 */ *((u16 *)buf) = decpair[q]; buf += 2; return buf; }

Contributors

PersonTokensPropCommitsCommitProp
denys vlasenkodenys vlasenko7853.79%240.00%
rasmus villemoesrasmus villemoes6544.83%120.00%
george spelvingeorge spelvin10.69%120.00%
joe perchesjoe perches10.69%120.00%
Total145100.00%5100.00%


static noinline_for_stack char *put_dec(char *buf, unsigned long long n) { if (n >= 100*1000*1000) buf = put_dec_full8(buf, do_div(n, 100*1000*1000)); /* 1 <= n <= 1.6e11 */ if (n >= 100*1000*1000) buf = put_dec_full8(buf, do_div(n, 100*1000*1000)); /* 1 <= n < 1e8 */ return put_dec_trunc8(buf, n); }

Contributors

PersonTokensPropCommitsCommitProp
denys vlasenkodenys vlasenko6578.31%150.00%
rasmus villemoesrasmus villemoes1821.69%150.00%
Total83100.00%2100.00%

#elif BITS_PER_LONG == 32 && BITS_PER_LONG_LONG == 64
static void put_dec_full4(char *buf, unsigned r) { unsigned q; /* 0 <= r < 10^4 */ q = (r * 0x147b) >> 19; *((u16 *)buf) = decpair[r - 100*q]; buf += 2; /* 0 <= q < 100 */ *((u16 *)buf) = decpair[q]; }

Contributors

PersonTokensPropCommitsCommitProp
denys vlasenkodenys vlasenko3554.69%133.33%
rasmus villemoesrasmus villemoes2437.50%133.33%
george spelvingeorge spelvin57.81%133.33%
Total64100.00%3100.00%

/* * Call put_dec_full4 on x % 10000, return x / 10000. * The approximation x/10000 == (x * 0x346DC5D7) >> 43 * holds for all x < 1,128,869,999. The largest value this * helper will ever be asked to convert is 1,125,520,955. * (second call in the put_dec code, assuming n is all-ones). */
static noinline_for_stack unsigned put_dec_helper4(char *buf, unsigned x) { uint32_t q = (x * (uint64_t)0x346DC5D7) >> 43; put_dec_full4(buf, x - q * 10000); return q; }

Contributors

PersonTokensPropCommitsCommitProp
george spelvingeorge spelvin3890.48%133.33%
denys vlasenkodenys vlasenko37.14%133.33%
rasmus villemoesrasmus villemoes12.38%133.33%
Total42100.00%3100.00%

/* Based on code by Douglas W. Jones found at * <http://www.cs.uiowa.edu/~jones/bcd/decimal.html#sixtyfour> * (with permission from the author). * Performs no 64-bit division and hence should be fast on 32-bit machines. */
static char *put_dec(char *buf, unsigned long long n) { uint32_t d3, d2, d1, q, h; if (n < 100*1000*1000) return put_dec_trunc8(buf, n); d1 = ((uint32_t)n >> 16); /* implicit "& 0xffff" */ h = (n >> 32); d2 = (h ) & 0xffff; d3 = (h >> 16); /* implicit "& 0xffff" */ /* n = 2^48 d3 + 2^32 d2 + 2^16 d1 + d0 = 281_4749_7671_0656 d3 + 42_9496_7296 d2 + 6_5536 d1 + d0 */ q = 656 * d3 + 7296 * d2 + 5536 * d1 + ((uint32_t)n & 0xffff); q = put_dec_helper4(buf, q); q += 7671 * d3 + 9496 * d2 + 6 * d1; q = put_dec_helper4(buf+4, q); q += 4749 * d3 + 42 * d2; q = put_dec_helper4(buf+8, q); q += 281 * d3; buf += 12; if (q) buf = put_dec_trunc8(buf, q); else while (buf[-1] == '0') --buf; return buf; }

Contributors

PersonTokensPropCommitsCommitProp
denys vlasenkodenys vlasenko18190.05%250.00%
george spelvingeorge spelvin199.45%125.00%
rasmus villemoesrasmus villemoes10.50%125.00%
Total201100.00%4100.00%

#endif /* * Convert passed number to decimal string. * Returns the length of string. On buffer overflow, returns 0. * * If speed is not important, use snprintf(). It's easy to read the code. */
int num_to_str(char *buf, int size, unsigned long long num) { /* put_dec requires 2-byte alignment of the buffer. */ char tmp[sizeof(num) * 3] __aligned(2); int idx, len; /* put_dec() may work incorrectly for num = 0 (generate "", not "0") */ if (num <= 9) { tmp[0] = '0' + num; len = 1; } else { len = put_dec(tmp, num) - tmp; } if (len > size) return 0; for (idx = 0; idx < len; ++idx) buf[idx] = tmp[len - idx - 1]; return len; }

Contributors

PersonTokensPropCommitsCommitProp
kamezawa hiroyukikamezawa hiroyuki7768.14%133.33%
denys vlasenkodenys vlasenko3127.43%133.33%
rasmus villemoesrasmus villemoes54.42%133.33%
Total113100.00%3100.00%

#define SIGN 1 /* unsigned/signed, must be 1 */ #define LEFT 2 /* left justified */ #define PLUS 4 /* show plus */ #define SPACE 8 /* space if plus */ #define ZEROPAD 16 /* pad with zero, must be 16 == '0' - ' ' */ #define SMALL 32 /* use lowercase in hex (must be 32 == 0x20) */ #define SPECIAL 64 /* prefix hex with "0x", octal with "0" */ enum format_type { FORMAT_TYPE_NONE, /* Just a string part */ FORMAT_TYPE_WIDTH, FORMAT_TYPE_PRECISION, FORMAT_TYPE_CHAR, FORMAT_TYPE_STR, FORMAT_TYPE_PTR, FORMAT_TYPE_PERCENT_CHAR, FORMAT_TYPE_INVALID, FORMAT_TYPE_LONG_LONG, FORMAT_TYPE_ULONG, FORMAT_TYPE_LONG, FORMAT_TYPE_UBYTE, FORMAT_TYPE_BYTE, FORMAT_TYPE_USHORT, FORMAT_TYPE_SHORT, FORMAT_TYPE_UINT, FORMAT_TYPE_INT, FORMAT_TYPE_SIZE_T, FORMAT_TYPE_PTRDIFF }; struct printf_spec { unsigned int type:8; /* format_type enum */ signed int field_width:24; /* width of output field */ unsigned int flags:8; /* flags to number() */ unsigned int base:8; /* number base, 8, 10 or 16 only */ signed int precision:16; /* # of digits/chars */ } __packed; #define FIELD_WIDTH_MAX ((1 << 23) - 1) #define PRECISION_MAX ((1 << 15) - 1)
static noinline_for_stack char *number(char *buf, char *end, unsigned long long num, struct printf_spec spec) { /* put_dec requires 2-byte alignment of the buffer. */ char tmp[3 * sizeof(num)] __aligned(2); char sign; char locase; int need_pfx = ((spec.flags & SPECIAL) && spec.base != 10); int i; bool is_zero = num == 0LL; int field_width = spec.field_width; int precision = spec.precision; BUILD_BUG_ON(sizeof(struct printf_spec) != 8); /* locase = 0 or 0x20. ORing digits or letters with 'locase' * produces same digits or (maybe lowercased) letters */ locase = (spec.flags & SMALL); if (spec.flags & LEFT) spec.flags &= ~ZEROPAD; sign = 0; if (spec.flags & SIGN) { if ((signed long long)num < 0) { sign = '-'; num = -(signed long long)num; field_width--; } else if (spec.flags & PLUS) { sign = '+'; field_width--; } else if (spec.flags & SPACE) { sign = ' '; field_width--; } } if (need_pfx) { if (spec.base == 16) field_width -= 2; else if (!is_zero) field_width--; } /* generate full string in tmp[], in reverse order */ i = 0; if (num < spec.base) tmp[i++] = hex_asc_upper[num] | locase; else if (spec.base != 10) { /* 8 or 16 */ int mask = spec.base - 1; int shift = 3; if (spec.base == 16) shift = 4; do { tmp[i++] = (hex_asc_upper[((unsigned char)num) & mask] | locase); num >>= shift; } while (num); } else { /* base 10 */ i = put_dec(tmp, num) - tmp; } /* printing 100 using %2d gives "100", not "00" */ if (i > precision) precision = i; /* leading space padding */ field_width -= precision; if (!(spec.flags & (ZEROPAD | LEFT))) { while (--field_width >= 0) { if (buf < end) *buf = ' '; ++buf; } } /* sign */ if (sign) { if (buf < end) *buf = sign; ++buf; } /* "0x" / "0" prefix */ if (need_pfx) { if (spec.base == 16 || !is_zero) { if (buf < end) *buf = '0'; ++buf; } if (spec.base == 16) { if (buf < end) *buf = ('X' | locase); ++buf; } } /* zero or space padding */ if (!(spec.flags & LEFT)) { char c = ' ' + (spec.flags & ZEROPAD); BUILD_BUG_ON(' ' + ZEROPAD != '0'); while (--field_width >= 0) { if (buf < end) *buf = c; ++buf; } } /* hmm even more zero padding? */ while (i <= --precision) { if (buf < end) *buf = '0'; ++buf; } /* actual digits of result */ while (--i >= 0) { if (buf < end) *buf = tmp[i]; ++buf; } /* trailing space padding */ while (--field_width >= 0) { if (buf < end) *buf = ' '; ++buf; } return buf; }

Contributors

PersonTokensPropCommitsCommitProp
pre-gitpre-git23437.50%417.39%
denys vlasenkodenys vlasenko13521.63%417.39%
linus torvaldslinus torvalds11217.95%313.04%
frederic weisbeckerfrederic weisbecker538.49%14.35%
rasmus villemoesrasmus villemoes508.01%730.43%
pierre carrierpierre carrier304.81%14.35%
jeremy fitzhardingejeremy fitzhardinge81.28%14.35%
joe perchesjoe perches10.16%14.35%
bernardo innocentibernardo innocenti10.16%14.35%
Total624100.00%23100.00%


static noinline_for_stack char *special_hex_number(char *buf, char *end, unsigned long long num, int size) { struct printf_spec spec; spec.type = FORMAT_TYPE_PTR; spec.field_width = 2 + 2 * size; /* 0x + hex */ spec.flags = SPECIAL | SMALL | ZEROPAD; spec.base = 16; spec.precision = -1; return number(buf, end, num, spec); }

Contributors

PersonTokensPropCommitsCommitProp
andy shevchenkoandy shevchenko80100.00%1100.00%
Total80100.00%1100.00%


static void move_right(char *buf, char *end, unsigned len, unsigned spaces) { size_t size; if (buf >= end) /* nowhere to put anything */ return; size = end - buf; if (size <= spaces) { memset(buf, ' ', size); return; } if (len) { if (len > size - spaces) len = size - spaces; memmove(buf + spaces, buf, len); } memset(buf, ' ', spaces); }

Contributors

PersonTokensPropCommitsCommitProp
al viroal viro9498.95%150.00%
rasmus villemoesrasmus villemoes11.05%150.00%
Total95100.00%2100.00%

/* * Handle field width padding for a string. * @buf: current buffer position * @n: length of string * @end: end of output buffer * @spec: for field width and flags * Returns: new buffer position after padding. */
static noinline_for_stack char *widen_string(char *buf, int n, char *end, struct printf_spec spec) { unsigned spaces; if (likely(n >= spec.field_width)) return buf; /* we want to pad the sucker */ spaces = spec.field_width - n; if (!(spec.flags & LEFT)) { move_right(buf - n, end, n, spaces); return buf + spaces; } while (spaces--) { if (buf < end) *buf = ' '; ++buf; } return buf; }

Contributors

PersonTokensPropCommitsCommitProp
rasmus villemoesrasmus villemoes104100.00%1100.00%
Total104100.00%1100.00%


static noinline_for_stack char *string(char *buf, char *end, const char *s, struct printf_spec spec) { int len = 0; size_t lim = spec.precision; if ((unsigned long)s < PAGE_SIZE) s = "(null)"; while (lim--) { char c = *s++; if (!c) break; if (buf < end) *buf = c; ++buf; ++len; } return widen_string(buf,