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