/*
* Taken from Linux kernel's linux/lib/vsprintf.c
* and somewhat simplified.
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
/* vsprintf.c -- Lars Wirzenius & Linus Torvalds. */
/*
* Wirzenius wrote this portably, Torvalds fucked it up :-)
*/
#include "defs.h"
#if USE_CUSTOM_PRINTF
#include <stdarg.h>
#include <limits.h>
#ifndef HAVE_FPUTS_UNLOCKED
# define fputs_unlocked fputs
#endif
#define noinline_for_stack /*nothing*/
#define likely(expr) (expr)
#define unlikely(expr) (expr)
#define do_div(n, d) ({ __typeof(num) t = n % d; n /= d; t; })
#undef isdigit
#define isdigit(a) ((unsigned char)((a) - '0') <= 9)
static inline
int skip_atoi(const char **s)
{
int i = 0;
const char *p = *s;
while (isdigit(*p))
i = i*10 + *p++ - '0';
*s = p;
return i;
}
/* 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
* using ideas described at <http://www.cs.uiowa.edu/~jones/bcd/divide.html>
* (with permission from the author, Douglas W. Jones).
*/
#if LONG_MAX != 0x7fffffffUL || LLONG_MAX != 0x7fffffffffffffffULL
/* Formats correctly any integer in [0, 999999999] */
static noinline_for_stack
char *put_dec_full9(char *buf, unsigned q)
{
unsigned r;
/* Possible ways to approx. divide by 10
* (x * 0x1999999a) >> 32 x < 1073741829 (multiply must be 64-bit)
* (x * 0xcccd) >> 19 x < 81920 (x < 262149 when 64-bit mul)
* (x * 0x6667) >> 18 x < 43699
* (x * 0x3334) >> 17 x < 16389
* (x * 0x199a) >> 16 x < 16389
* (x * 0x0ccd) >> 15 x < 16389
* (x * 0x0667) >> 14 x < 2739
* (x * 0x0334) >> 13 x < 1029
* (x * 0x019a) >> 12 x < 1029
* (x * 0x00cd) >> 11 x < 1029 shorter code than * 0x67 (on i386)
* (x * 0x0067) >> 10 x < 179
* (x * 0x0034) >> 9 x < 69 same
* (x * 0x001a) >> 8 x < 69 same
* (x * 0x000d) >> 7 x < 69 same, shortest code (on i386)
* (x * 0x0007) >> 6 x < 19
* See <http://www.cs.uiowa.edu/~jones/bcd/divide.html>
*/
r = (q * (uint64_t)0x1999999a) >> 32;
*buf++ = (q - 10 * r) + '0'; /* 1 */
q = (r * (uint64_t)0x1999999a) >> 32;
*buf++ = (r - 10 * q) + '0'; /* 2 */
r = (q * (uint64_t)0x1999999a) >> 32;
*buf++ = (q - 10 * r) + '0'; /* 3 */
q = (r * (uint64_t)0x1999999a) >> 32;
*buf++ = (r - 10 * q) + '0'; /* 4 */
r = (q * (uint64_t)0x1999999a) >> 32;
*buf++ = (q - 10 * r) + '0'; /* 5 */
/* Now value is under 10000, can avoid 64-bit multiply */
q = (r * 0x199a) >> 16;
*buf++ = (r - 10 * q) + '0'; /* 6 */
r = (q * 0xcd) >> 11;
*buf++ = (q - 10 * r) + '0'; /* 7 */
q = (r * 0xcd) >> 11;
*buf++ = (r - 10 * q) + '0'; /* 8 */
*buf++ = q + '0'; /* 9 */
return buf;
}
#endif
/* Similar to above but do not pad with zeros.
* Code can be easily arranged to print 9 digits too, but our callers
* always call put_dec_full9() instead when the number has 9 decimal digits.
*/
static noinline_for_stack
char *put_dec_trunc8(char *buf, unsigned r)
{
unsigned q;
/* Copy of previous function's body with added early returns */
q = (r * (uint64_t)0x1999999a) >> 32;
*buf++ = (r - 10 * q) + '0'; /* 2 */
if (q == 0) return buf;
r = (q * (uint64_t)0x1999999a) >> 32;
*buf++ = (q - 10 * r) + '0'; /* 3 */
if (r == 0) return buf;
q = (r * (uint64_t)0x1999999a) >> 32;
*buf++ = (r - 10 * q) + '0'; /* 4 */
if (q == 0) return buf;
r = (q * (uint64_t)0x1999999a) >> 32;
*buf++ = (q - 10 * r) + '0'; /* 5 */
if (r == 0) return buf;
q = (r * 0x199a) >> 16;
*buf++ = (r - 10 * q) + '0'; /* 6 */
if (q == 0) return buf;
r = (q * 0xcd) >> 11;
*buf++ = (q - 10 * r) + '0'; /* 7 */
if (r == 0) return buf;
q = (r * 0xcd) >> 11;
*buf++ = (r - 10 * q) + '0'; /* 8 */
if (q == 0) return buf;
*buf++ = q + '0'; /* 9 */
return buf;
}
/* There are two algorithms to print larger numbers.
* One is generic: divide by 1000000000 and repeatedly print
* groups of (up to) 9 digits. It's conceptually simple,
* but requires a (unsigned long long) / 1000000000 division.
*
* Second algorithm splits 64-bit unsigned long long into 16-bit chunks,
* manipulates them cleverly and generates groups of 4 decimal digits.
* It so happens that it does NOT require long long division.
*
* If long is > 32 bits, division of 64-bit values is relatively easy,
* and we will use the first algorithm.
* If long long is > 64 bits (strange architecture with VERY large long long),
* second algorithm can't be used, and we again use the first one.
*
* Else (if long is 32 bits and long long is 64 bits) we use second one.
*/
#if LONG_MAX != 0x7fffffffUL || LLONG_MAX != 0x7fffffffffffffffULL
/* First algorithm: generic */
static
char *put_dec(char *buf, unsigned long long n)
{
if (n >= 100*1000*1000) {
while (n >= 1000*1000*1000)
buf = put_dec_full9(buf, do_div(n, 1000*1000*1000));
if (n >= 100*1000*1000)
return put_dec_full9(buf, n);
}
return put_dec_trunc8(buf, n);
}
#else
/* Second algorithm: valid only for 64-bit long longs */
static noinline_for_stack
char *put_dec_full4(char *buf, unsigned q)
{
unsigned r;
r = (q * 0xcccd) >> 19;
*buf++ = (q - 10 * r) + '0';
q = (r * 0x199a) >> 16;
*buf++ = (r - 10 * q) + '0';
r = (q * 0xcd) >> 11;
*buf++ = (q - 10 * r) + '0';
*buf++ = r + '0';
return buf;
}
/* 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" */
q = 656 * d3 + 7296 * d2 + 5536 * d1 + ((uint32_t)n & 0xffff);
buf = put_dec_full4(buf, q % 10000);
q = q / 10000;
d1 = q + 7671 * d3 + 9496 * d2 + 6 * d1;
buf = put_dec_full4(buf, d1 % 10000);
q = d1 / 10000;
d2 = q + 4749 * d3 + 42 * d2;
buf = put_dec_full4(buf, d2 % 10000);
q = d2 / 10000;
d3 = q + 281 * d3;
if (!d3)
goto done;
buf = put_dec_full4(buf, d3 % 10000);
q = d3 / 10000;
if (!q)
goto done;
buf = put_dec_full4(buf, q);
done:
while (buf[-1] == '0')
--buf;
return buf;
}
#endif
/*
* For strace, the following formats are not supported:
* %h[h]u, %zu, %tu - use [unsigned] int/long/long long fmt instead
* %8.4u - no precision field for integers allowed (ok for strings)
* %+d, % d - no forced sign or force "space positive" sign
* %-07u - use %-7u instead
* %X - works as %x
*/
#define ZEROPAD 1 /* pad with zero */
#define SIGN 2 /* unsigned/signed long */
//#define PLUS 4 /* show plus */
//#define SPACE 8 /* space if plus */
#define LEFT 16 /* left justified */
//#deefine 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_UINT,
FORMAT_TYPE_INT,
};
struct printf_spec {
uint8_t type; /* format_type enum */
uint8_t flags; /* flags to number() */
uint8_t base; /* number base, 8, 10 or 16 only */
uint8_t qualifier; /* number qualifier, one of 'hHlLtzZ' */
int field_width; /* width of output field */
int precision; /* # of digits/chars */
};
static noinline_for_stack
char *number(char *buf, char *end, unsigned long long num,
struct printf_spec spec)
{
/* we are called with base 8, 10 or 16, only, thus don't need "G..." */
static const char digits[16] = "0123456789abcdef"; /* "GHIJKLMNOPQRSTUVWXYZ"; */
char tmp[sizeof(long long)*3 + 4];
char sign;
int need_pfx = ((spec.flags & SPECIAL) && spec.base != 10);
int i;
/* We may overflow the buf. Crudely check for it */
i = sizeof(long long)*3 + 4;
if (i < spec.field_width)
i = spec.field_width;
if ((end - buf) <= i)
return buf + i;
//we don't use formats like "%-07u"
// 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;
spec.field_width--;
// } else if (spec.flags & PLUS) {
// sign = '+';
// spec.field_width--;
// } else if (spec.flags & SPACE) {
// sign = ' ';
// spec.field_width--;
}
}
if (need_pfx) {
spec.field_width--;
if (spec.base == 16)
spec.field_width--;
}
/* generate full string in tmp[], in reverse order */
i = 0;
if (num < spec.base)
tmp[i++] = digits[num];
/* Generic code, for any base:
else do {
tmp[i++] = (digits[do_div(num,base)]);
} while (num != 0);
*/
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++] = digits[((unsigned char)num) & mask];
num >>= shift;
} while (num);
} else { /* base 10 */
i = put_dec(tmp, num) - tmp;
}
//spec.precision is assumed 0 ("not specified")
// /* printing 100 using %2d gives "100", not "00" */
// if (i > spec.precision)
// spec.precision = i;
// /* leading space padding */
// spec.field_width -= spec.precision;
spec.field_width -= i;
if (!(spec.flags & (ZEROPAD+LEFT))) {
while (--spec.field_width >= 0) {
///if (buf < end)
*buf = ' ';
++buf;
}
}
/* sign */
if (sign) {
///if (buf < end)
*buf = sign;
++buf;
}
/* "0x" / "0" prefix */
if (need_pfx) {
///if (buf < end)
*buf = '0';
++buf;
if (spec.base == 16) {
///if (buf < end)
*buf = 'x';
++buf;
}
}
/* zero or space padding */
if (!(spec.flags & LEFT)) {
char c = (spec.flags & ZEROPAD) ? '0' : ' ';
while (--spec.field_width >= 0) {
///if (buf < end)
*buf = c;
++buf;
}
}
// /* hmm even more zero padding? */
// while (i <= --spec.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 (--spec.field_width >= 0) {
///if (buf < end)
*buf = ' ';
++buf;
}
return buf;
}
static noinline_for_stack
char *string(char *buf, char *end, const char *s, struct printf_spec spec)
{
int len, i;
if (!s)
s = "(null)";
len = strnlen(s, spec.precision);
/* We may overflow the buf. Crudely check for it */
i = len;
if (i < spec.field_width)
i = spec.field_width;
if ((end - buf) <= i)
return buf + i;
if (!(spec.flags & LEFT)) {
while (len < spec.field_width--) {
///if (buf < end)
*buf = ' ';
++buf;
}
}
for (i = 0; i < len; ++i) {
///if (buf < end)
*buf = *s;
++buf; ++s;
}
while (len < spec.field_width--) {
///if (buf < end)
*buf = ' ';
++buf;
}
return buf;
}
static noinline_for_stack
char *pointer(const char *fmt, char *buf, char *end, void *ptr,
struct printf_spec spec)
{
// spec.flags |= SMALL;
if (spec.field_width == -1) {
spec.field_width = 2 * sizeof(void *);
spec.flags |= ZEROPAD;
}
spec.base = 16;
return number(buf, end, (unsigned long) ptr, spec);
}
/*
* Helper function to decode printf style format.
* Each call decode a token from the format and return the
* number of characters read (or likely the delta where it wants
* to go on the next call).
* The decoded token is returned through the parameters
*
* 'h', 'l', or 'L' for integer fields
* 'z' support added 23/7/1999 S.H.
* 'z' changed to 'Z' --davidm 1/25/99
* 't' added for ptrdiff_t
*
* @fmt: the format string
* @type of the token returned
* @flags: various flags such as +, -, # tokens..
* @field_width: overwritten width
* @base: base of the number (octal, hex, ...)
* @precision: precision of a number
* @qualifier: qualifier of a number (long, size_t, ...)
*/
static noinline_for_stack
int format_decode(const char *fmt, struct printf_spec *spec)
{
const char *start = fmt;
/* we finished early by reading the field width */
if (spec->type == FORMAT_TYPE_WIDTH) {
if (spec->field_width < 0) {
spec->field_width = -spec->field_width;
spec->flags |= LEFT;
}
spec->type = FORMAT_TYPE_NONE;
goto precision;
}
/* we finished early by reading the precision */
if (spec->type == FORMAT_TYPE_PRECISION) {
if (spec->precision < 0)
spec->precision = 0;
spec->type = FORMAT_TYPE_NONE;
goto qualifier;
}
/* By default */
spec->type = FORMAT_TYPE_NONE;
for (;;) {
if (*fmt == '\0')
return fmt - start;
if (*fmt == '%')
break;
++fmt;
}
/* Return the current non-format string */
if (fmt != start)
return fmt - start;
/* Process flags */
spec->flags = 0;
while (1) { /* this also skips first '%' */
bool found = true;
++fmt;
switch (*fmt) {
case '-': spec->flags |= LEFT; break;
// case '+': spec->flags |= PLUS; break;
// case ' ': spec->flags |= SPACE; break;
case '#': spec->flags |= SPECIAL; break;
case '0': spec->flags |= ZEROPAD; break;
default: found = false;
}
if (!found)
break;
}
/* get field width */
spec->field_width = -1;
if (isdigit(*fmt))
spec->field_width = skip_atoi(&fmt);
else if (*fmt == '*') {
/* it's the next argument */
spec->type = FORMAT_TYPE_WIDTH;
return ++fmt - start;
}
precision:
/* get the precision */
spec->precision = -1;
if (*fmt == '.') {
++fmt;
if (isdigit(*fmt)) {
spec->precision = skip_atoi(&fmt);
// if (spec->precision < 0)
// spec->precision = 0;
} else if (*fmt == '*') {
/* it's the next argument */
spec->type = FORMAT_TYPE_PRECISION;
return ++fmt - start;
}
}
qualifier:
/* get the conversion qualifier */
spec->qualifier = -1;
if (*fmt == 'l') {
spec->qualifier = *fmt++;
if (unlikely(spec->qualifier == *fmt)) {
spec->qualifier = 'L';
++fmt;
}
}
/* default base */
spec->base = 10;
switch (*fmt) {
case 'c':
spec->type = FORMAT_TYPE_CHAR;
return ++fmt - start;
case 's':
spec->type = FORMAT_TYPE_STR;
return ++fmt - start;
case 'p':
spec->type = FORMAT_TYPE_PTR;
return ++fmt - start;
case '%':
spec->type = FORMAT_TYPE_PERCENT_CHAR;
return ++fmt - start;
/* integer number formats - set up the flags and "break" */
case 'o':
spec->base = 8;
break;
case 'x':
// spec->flags |= SMALL;
case 'X':
spec->base = 16;
break;
case 'd':
case 'i':
spec->flags |= SIGN;
case 'u':
break;
default:
spec->type = FORMAT_TYPE_INVALID;
return fmt - start;
}
if (spec->qualifier == 'L')
spec->type = FORMAT_TYPE_LONG_LONG;
else if (spec->qualifier == 'l') {
if (spec->flags & SIGN)
spec->type = FORMAT_TYPE_LONG;
else
spec->type = FORMAT_TYPE_ULONG;
} else {
if (spec->flags & SIGN)
spec->type = FORMAT_TYPE_INT;
else
spec->type = FORMAT_TYPE_UINT;
}
return ++fmt - start;
}
/**
* vsnprintf - Format a string and place it in a buffer
* @buf: The buffer to place the result into
* @size: The size of the buffer, including the trailing null space
* @fmt: The format string to use
* @args: Arguments for the format string
*
* The return value is the number of characters which would
* be generated for the given input, excluding the trailing
* '\0', as per ISO C99. If you want to have the exact
* number of characters written into @buf as return value
* (not including the trailing '\0'), use vscnprintf(). If the
* return is greater than or equal to @size, the resulting
* string is truncated.
*
* If you're not already dealing with a va_list consider using snprintf().
*/
static
int kernel_vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
{
unsigned long long num;
char *str, *end;
struct printf_spec spec = {0};
str = buf;
end = buf + size;
while (*fmt) {
const char *old_fmt = fmt;
int read = format_decode(fmt, &spec);
fmt += read;
switch (spec.type) {
case FORMAT_TYPE_NONE: {
int copy = read;
if (str < end) {
if (copy > end - str)
copy = end - str;
memcpy(str, old_fmt, copy);
}
str += read;
break;
}
case FORMAT_TYPE_WIDTH:
spec.field_width = va_arg(args, int);
break;
case FORMAT_TYPE_PRECISION:
spec.precision = va_arg(args, int);
break;
case FORMAT_TYPE_CHAR: {
char c;
if (!(spec.flags & LEFT)) {
while (--spec.field_width > 0) {
if (str < end)
*str = ' ';
++str;
}
}
c = (unsigned char) va_arg(args, int);
if (str < end)
*str = c;
++str;
while (--spec.field_width > 0) {
if (str < end)
*str = ' ';
++str;
}
break;
}
case FORMAT_TYPE_STR:
str = string(str, end, va_arg(args, char *), spec);
break;
case FORMAT_TYPE_PTR:
str = pointer(fmt+1, str, end, va_arg(args, void *),
spec);
// while (isalnum(*fmt))
// fmt++;
break;
case FORMAT_TYPE_PERCENT_CHAR:
if (str < end)
*str = '%';
++str;
break;
case FORMAT_TYPE_INVALID:
if (str < end)
*str = '%';
++str;
break;
default:
switch (spec.type) {
case FORMAT_TYPE_LONG_LONG:
num = va_arg(args, long long);
break;
case FORMAT_TYPE_ULONG:
num = va_arg(args, unsigned long);
break;
case FORMAT_TYPE_LONG:
num = va_arg(args, long);
break;
case FORMAT_TYPE_INT:
num = (int) va_arg(args, int);
break;
default:
num = va_arg(args, unsigned int);
}
str = number(str, end, num, spec);
}
}
// if (size > 0) {
if (str < end)
*str = '\0';
// else
// end[-1] = '\0';
// }
/* the trailing null byte doesn't count towards the total */
return str-buf;
}
int strace_vfprintf(FILE *fp, const char *fmt, va_list args)
{
static char *buf = NULL;
static unsigned buflen = 0;
int r;
va_list a1;
va_copy(a1, args);
unsigned len = kernel_vsnprintf(buf, buflen, fmt, a1);
va_end(a1);
if (len >= buflen) {
buflen = len + 256;
free(buf);
buf = malloc(buflen);
if (!buf)
die_out_of_memory();
/*len =*/ kernel_vsnprintf(buf, buflen, fmt, args);
}
r = fputs_unlocked(buf, fp);
if (r < 0) return r;
return len;
}
#endif /* USE_CUSTOM_PRINTF */