/*
* Helpers for formatting and printing strings
*
* Copyright 31 August 2008 James Bottomley
* Copyright (C) 2013, Intel Corporation
*/
#include <linux/kernel.h>
#include <linux/math64.h>
#include <linux/export.h>
#include <linux/ctype.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/string_helpers.h>
/**
* string_get_size - get the size in the specified units
* @size: The size to be converted
* @units: units to use (powers of 1000 or 1024)
* @buf: buffer to format to
* @len: length of buffer
*
* This function returns a string formatted to 3 significant figures
* giving the size in the required units. @buf should have room for
* at least 9 bytes and will always be zero terminated.
*
*/
void string_get_size(u64 size, const enum string_size_units units,
char *buf, int len)
{
static const char *const units_10[] = {
"B", "kB", "MB", "GB", "TB", "PB", "EB"
};
static const char *const units_2[] = {
"B", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB"
};
static const char *const *const units_str[] = {
[STRING_UNITS_10] = units_10,
[STRING_UNITS_2] = units_2,
};
static const unsigned int divisor[] = {
[STRING_UNITS_10] = 1000,
[STRING_UNITS_2] = 1024,
};
int i, j;
u32 remainder = 0, sf_cap;
char tmp[8];
tmp[0] = '\0';
i = 0;
if (size >= divisor[units]) {
while (size >= divisor[units]) {
remainder = do_div(size, divisor[units]);
i++;
}
sf_cap = size;
for (j = 0; sf_cap*10 < 1000; j++)
sf_cap *= 10;
if (j) {
remainder *= 1000;
remainder /= divisor[units];
snprintf(tmp, sizeof(tmp), ".%03u", remainder);
tmp[j+1] = '\0';
}
}
snprintf(buf, len, "%u%s %s", (u32)size,
tmp, units_str[units][i]);
}
EXPORT_SYMBOL(string_get_size);
static bool unescape_space(char **src, char **dst)
{
char *p = *dst, *q = *src;
switch (*q) {
case 'n':
*p = '\n';
break;
case 'r':
*p = '\r';
break;
case 't':
*p = '\t';
break;
case 'v':
*p = '\v';
break;
case 'f':
*p = '\f';
break;
default:
return false;
}
*dst += 1;
*src += 1;
return true;
}
static bool unescape_octal(char **src, char **dst)
{
char *p = *dst, *q = *src;
u8 num;
if (isodigit(*q) == 0)
return false;
num = (*q++) & 7;
while (num < 32 && isodigit(*q) && (q - *src < 3)) {
num <<= 3;
num += (*q++) & 7;
}
*p = num;
*dst += 1;
*src = q;
return true;
}
static bool unescape_hex(char **src, char **dst)
{
char *p = *dst, *q = *src;
int digit;
u8 num;
if (*q++ != 'x')
return false;
num = digit = hex_to_bin(*q++);
if (digit < 0)
return false;
digit = hex_to_bin(*q);
if (digit >= 0) {
q++;
num = (num << 4) | digit;
}
*p = num;
*dst += 1;
*src = q;
return true;
}
static bool unescape_special(char **src, char **dst)
{
char *p = *dst, *q = *src;
switch (*q) {
case '\"':
*p = '\"';
break;
case '\\':
*p = '\\';
break;
case 'a':
*p = '\a';
break;
case 'e':
*p = '\e';
break;
default:
return false;
}
*dst += 1;
*src += 1;
return true;
}
/**
* string_unescape - unquote characters in the given string
* @src: source buffer (escaped)
* @dst: destination buffer (unescaped)
* @size: size of the destination buffer (0 to unlimit)
* @flags: combination of the flags (bitwise OR):
* %UNESCAPE_SPACE:
* '\f' - form feed
* '\n' - new line
* '\r' - carriage return
* '\t' - horizontal tab
* '\v' - vertical tab
* %UNESCAPE_OCTAL:
* '\NNN' - byte with octal value NNN (1 to 3 digits)
* %UNESCAPE_HEX:
* '\xHH' - byte with hexadecimal value HH (1 to 2 digits)
* %UNESCAPE_SPECIAL:
* '\"' - double quote
* '\\' - backslash
* '\a' - alert (BEL)
* '\e' - escape
* %UNESCAPE_ANY:
* all previous together
*
* Description:
* The function unquotes characters in the given string.
*
* Because the size of the output will be the same as or less than the size of
* the input, the transformation may be performed in place.
*
* Caller must provide valid source and destination pointers. Be aware that
* destination buffer will always be NULL-terminated. Source string must be
* NULL-terminated as well.
*
* Return:
* The amount of the characters processed to the destination buffer excluding
* trailing '\0' is returned.
*/
int string_unescape(char *src, char *dst, size_t size, unsigned int flags)
{
char *out = dst;
while (*src && --size) {
if (src[0] == '\\' && src[1] != '\0' && size > 1) {
src++;
size--;
if (flags & UNESCAPE_SPACE &&
unescape_space(&src, &out))
continue;
if (flags & UNESCAPE_OCTAL &&
unescape_octal(&src, &out))
continue;
if (flags & UNESCAPE_HEX &&
unescape_hex(&src, &out))
continue;
if (flags & UNESCAPE_SPECIAL &&
unescape_special(&src, &out))
continue;
*out++ = '\\';
}
*out++ = *src++;
}
*out = '\0';
return out - dst;
}
EXPORT_SYMBOL(string_unescape);
static int escape_passthrough(unsigned char c, char **dst, size_t *osz)
{
char *out = *dst;
if (*osz < 1)
return -ENOMEM;
*out++ = c;
*dst = out;
*osz -= 1;
return 1;
}
static int escape_space(unsigned char c, char **dst, size_t *osz)
{
char *out = *dst;
unsigned char to;
if (*osz < 2)
return -ENOMEM;
switch (c) {
case '\n':
to = 'n';
break;
case '\r':
to = 'r';
break;
case '\t':
to = 't';
break;
case '\v':
to = 'v';
break;
case '\f':
to = 'f';
break;
default:
return 0;
}
*out++ = '\\';
*out++ = to;
*dst = out;
*osz -= 2;
return 1;
}
static int escape_special(unsigned char c, char **dst, size_t *osz)
{
char *out = *dst;
unsigned char to;
if (*osz < 2)
return -ENOMEM;
switch (c) {
case '\\':
to = '\\';
break;
case '\a':
to = 'a';
break;
case '\e':
to = 'e';
break;
default:
return 0;
}
*out++ = '\\';
*out++ = to;
*dst = out;
*osz -= 2;
return 1;
}
static int escape_null(unsigned char c, char **dst, size_t *osz)
{
char *out = *dst;
if (*osz < 2)
return -ENOMEM;
if (c)
return 0;
*out++ = '\\';
*out++ = '0';
*dst = out;
*osz -= 2;
return 1;
}
static int escape_octal(unsigned char c, char **dst, size_t *osz)
{
char *out = *dst;
if (*osz < 4)
return -ENOMEM;
*out++ = '\\';
*out++ = ((c >> 6) & 0x07) + '0';
*out++ = ((c >> 3) & 0x07) + '0';
*out++ = ((c >> 0) & 0x07) + '0';
*dst = out;
*osz -= 4;
return 1;
}
static int escape_hex(unsigned char c, char **dst, size_t *osz)
{
char *out = *dst;
if (*osz < 4)
return -ENOMEM;
*out++ = '\\';
*out++ = 'x';
*out++ = hex_asc_hi(c);
*out++ = hex_asc_lo(c);
*dst = out;
*osz -= 4;
return 1;
}
/**
* string_escape_mem - quote characters in the given memory buffer
* @src: source buffer (unescaped)
* @isz: source buffer size
* @dst: destination buffer (escaped)
* @osz: destination buffer size
* @flags: combination of the flags (bitwise OR):
* %ESCAPE_SPACE:
* '\f' - form feed
* '\n' - new line
* '\r' - carriage return
* '\t' - horizontal tab
* '\v' - vertical tab
* %ESCAPE_SPECIAL:
* '\\' - backslash
* '\a' - alert (BEL)
* '\e' - escape
* %ESCAPE_NULL:
* '\0' - null
* %ESCAPE_OCTAL:
* '\NNN' - byte with octal value NNN (3 digits)
* %ESCAPE_ANY:
* all previous together
* %ESCAPE_NP:
* escape only non-printable characters (checked by isprint)
* %ESCAPE_ANY_NP:
* all previous together
* %ESCAPE_HEX:
* '\xHH' - byte with hexadecimal value HH (2 digits)
* @esc: NULL-terminated string of characters any of which, if found in
* the source, has to be escaped
*
* Description:
* The process of escaping byte buffer includes several parts. They are applied
* in the following sequence.
* 1. The character is matched to the printable class, if asked, and in
* case of match it passes through to the output.
* 2. The character is not matched to the one from @esc string and thus
* must go as is to the output.
* 3. The character is checked if it falls into the class given by @flags.
* %ESCAPE_OCTAL and %ESCAPE_HEX are going last since they cover any
* character. Note that they actually can't go together, otherwise
* %ESCAPE_HEX will be ignored.
*
* Caller must provide valid source and destination pointers. Be aware that
* destination buffer will not be NULL-terminated, thus caller have to append
* it if needs.
*
* Return:
* The amount of the characters processed to the destination buffer, or
* %-ENOMEM if the size of buffer is not enough to put an escaped character is
* returned.
*
* Even in the case of error @dst pointer will be updated to point to the byte
* after the last processed character.
*/
int string_escape_mem(const char *src, size_t isz, char **dst, size_t osz,
unsigned int flags, const char *esc)
{
char *out = *dst, *p = out;
bool is_dict = esc && *esc;
int ret = 0;
while (isz--) {
unsigned char c = *src++;
/*
* Apply rules in the following sequence:
* - the character is printable, when @flags has
* %ESCAPE_NP bit set
* - the @esc string is supplied and does not contain a
* character under question
* - the character doesn't fall into a class of symbols
* defined by given @flags
* In these cases we just pass through a character to the
* output buffer.
*/
if ((flags & ESCAPE_NP && isprint(c)) ||
(is_dict && !strchr(esc, c))) {
/* do nothing */
} else {
if (flags & ESCAPE_SPACE) {
ret = escape_space(c, &p, &osz);
if (ret < 0)
break;
if (ret > 0)
continue;
}
if (flags & ESCAPE_SPECIAL) {
ret = escape_special(c, &p, &osz);
if (ret < 0)
break;
if (ret > 0)
continue;
}
if (flags & ESCAPE_NULL) {
ret = escape_null(c, &p, &osz);
if (ret < 0)
break;
if (ret > 0)
continue;
}
/* ESCAPE_OCTAL and ESCAPE_HEX always go last */
if (flags & ESCAPE_OCTAL) {
ret = escape_octal(c, &p, &osz);
if (ret < 0)
break;
continue;
}
if (flags & ESCAPE_HEX) {
ret = escape_hex(c, &p, &osz);
if (ret < 0)
break;
continue;
}
}
ret = escape_passthrough(c, &p, &osz);
if (ret < 0)
break;
}
*dst = p;
if (ret < 0)
return ret;
return p - out;
}
EXPORT_SYMBOL(string_escape_mem);
