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674 lines
14 KiB
674 lines
14 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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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/bug.h> |
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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/fs.h> |
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#include <linux/limits.h> |
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#include <linux/mm.h> |
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#include <linux/slab.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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/** |
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* string_get_size - get the size in the specified units |
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* @size: The size to be converted in blocks |
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* @blk_size: Size of the block (use 1 for size in bytes) |
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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. @buf should have room for |
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* at least 9 bytes and will always be zero terminated. |
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* |
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*/ |
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void string_get_size(u64 size, u64 blk_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" |
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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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}; |
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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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static const unsigned int rounding[] = { 500, 50, 5 }; |
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int i = 0, j; |
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u32 remainder = 0, sf_cap; |
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char tmp[8]; |
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const char *unit; |
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tmp[0] = '\0'; |
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|
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if (blk_size == 0) |
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size = 0; |
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if (size == 0) |
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goto out; |
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|
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/* This is Napier's algorithm. Reduce the original block size to |
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* |
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* coefficient * divisor[units]^i |
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* |
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* we do the reduction so both coefficients are just under 32 bits so |
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* that multiplying them together won't overflow 64 bits and we keep |
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* as much precision as possible in the numbers. |
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* |
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* Note: it's safe to throw away the remainders here because all the |
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* precision is in the coefficients. |
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*/ |
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while (blk_size >> 32) { |
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do_div(blk_size, divisor[units]); |
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i++; |
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} |
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|
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while (size >> 32) { |
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do_div(size, divisor[units]); |
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i++; |
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} |
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|
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/* now perform the actual multiplication keeping i as the sum of the |
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* two logarithms */ |
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size *= blk_size; |
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|
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/* and logarithmically reduce it until it's just under the divisor */ |
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while (size >= divisor[units]) { |
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remainder = do_div(size, divisor[units]); |
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i++; |
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} |
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|
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/* work out in j how many digits of precision we need from the |
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* remainder */ |
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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 (units == STRING_UNITS_2) { |
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/* express the remainder as a decimal. It's currently the |
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* numerator of a fraction whose denominator is |
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* divisor[units], which is 1 << 10 for STRING_UNITS_2 */ |
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remainder *= 1000; |
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remainder >>= 10; |
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} |
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|
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/* add a 5 to the digit below what will be printed to ensure |
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* an arithmetical round up and carry it through to size */ |
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remainder += rounding[j]; |
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if (remainder >= 1000) { |
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remainder -= 1000; |
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size += 1; |
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} |
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if (j) { |
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snprintf(tmp, sizeof(tmp), ".%03u", remainder); |
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tmp[j+1] = '\0'; |
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} |
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out: |
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if (i >= ARRAY_SIZE(units_2)) |
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unit = "UNK"; |
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else |
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unit = units_str[units][i]; |
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snprintf(buf, len, "%u%s %s", (u32)size, |
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tmp, unit); |
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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. |
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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. The supported flags are:: |
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* |
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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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* 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 bool escape_passthrough(unsigned char c, char **dst, char *end) |
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{ |
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char *out = *dst; |
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if (out < end) |
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*out = c; |
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*dst = out + 1; |
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return true; |
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} |
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static bool escape_space(unsigned char c, char **dst, char *end) |
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{ |
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char *out = *dst; |
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unsigned char to; |
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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 false; |
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} |
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if (out < end) |
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*out = '\\'; |
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++out; |
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if (out < end) |
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*out = to; |
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++out; |
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*dst = out; |
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return true; |
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} |
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static bool escape_special(unsigned char c, char **dst, char *end) |
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{ |
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char *out = *dst; |
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unsigned char to; |
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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 false; |
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} |
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if (out < end) |
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*out = '\\'; |
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++out; |
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if (out < end) |
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*out = to; |
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++out; |
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*dst = out; |
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return true; |
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} |
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static bool escape_null(unsigned char c, char **dst, char *end) |
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{ |
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char *out = *dst; |
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if (c) |
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return false; |
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if (out < end) |
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*out = '\\'; |
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++out; |
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if (out < end) |
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*out = '0'; |
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++out; |
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*dst = out; |
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return true; |
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} |
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static bool escape_octal(unsigned char c, char **dst, char *end) |
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{ |
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char *out = *dst; |
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if (out < end) |
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*out = '\\'; |
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++out; |
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if (out < end) |
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*out = ((c >> 6) & 0x07) + '0'; |
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++out; |
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if (out < end) |
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*out = ((c >> 3) & 0x07) + '0'; |
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++out; |
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if (out < end) |
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*out = ((c >> 0) & 0x07) + '0'; |
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++out; |
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*dst = out; |
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return true; |
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} |
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static bool escape_hex(unsigned char c, char **dst, char *end) |
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{ |
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char *out = *dst; |
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if (out < end) |
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*out = '\\'; |
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++out; |
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if (out < end) |
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*out = 'x'; |
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++out; |
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if (out < end) |
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*out = hex_asc_hi(c); |
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++out; |
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if (out < end) |
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*out = hex_asc_lo(c); |
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++out; |
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*dst = out; |
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return true; |
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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 |
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* @only: NULL-terminated string containing characters used to limit |
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* the selected escape class. If characters are included in @only |
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* that would not normally be escaped by the classes selected |
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* in @flags, they will be copied to @dst unescaped. |
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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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* |
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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 @only 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. The supported flags are:: |
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* |
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* %ESCAPE_SPACE: (special white space, not space itself) |
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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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* |
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* Return: |
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* The total size of the escaped output that would be generated for |
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* the given input and flags. To check whether the output was |
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* truncated, compare the return value to osz. There is room left in |
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* dst for a '\0' terminator if and only if ret < osz. |
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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 *only) |
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{ |
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char *p = dst; |
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char *end = p + osz; |
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bool is_dict = only && *only; |
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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 @only 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(only, c))) { |
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/* do nothing */ |
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} else { |
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if (flags & ESCAPE_SPACE && escape_space(c, &p, end)) |
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continue; |
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if (flags & ESCAPE_SPECIAL && escape_special(c, &p, end)) |
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continue; |
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if (flags & ESCAPE_NULL && escape_null(c, &p, end)) |
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continue; |
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/* ESCAPE_OCTAL and ESCAPE_HEX always go last */ |
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if (flags & ESCAPE_OCTAL && escape_octal(c, &p, end)) |
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continue; |
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if (flags & ESCAPE_HEX && escape_hex(c, &p, end)) |
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continue; |
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} |
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escape_passthrough(c, &p, end); |
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} |
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return p - dst; |
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} |
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EXPORT_SYMBOL(string_escape_mem); |
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int string_escape_mem_ascii(const char *src, size_t isz, char *dst, |
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size_t osz) |
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{ |
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char *p = dst; |
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char *end = p + osz; |
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while (isz--) { |
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unsigned char c = *src++; |
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if (!isprint(c) || !isascii(c) || c == '"' || c == '\\') |
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escape_hex(c, &p, end); |
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else |
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escape_passthrough(c, &p, end); |
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} |
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return p - dst; |
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} |
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EXPORT_SYMBOL(string_escape_mem_ascii); |
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|
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/* |
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* Return an allocated string that has been escaped of special characters |
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* and double quotes, making it safe to log in quotes. |
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*/ |
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char *kstrdup_quotable(const char *src, gfp_t gfp) |
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{ |
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size_t slen, dlen; |
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char *dst; |
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const int flags = ESCAPE_HEX; |
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const char esc[] = "\f\n\r\t\v\a\e\\\""; |
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if (!src) |
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return NULL; |
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slen = strlen(src); |
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dlen = string_escape_mem(src, slen, NULL, 0, flags, esc); |
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dst = kmalloc(dlen + 1, gfp); |
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if (!dst) |
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return NULL; |
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WARN_ON(string_escape_mem(src, slen, dst, dlen, flags, esc) != dlen); |
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dst[dlen] = '\0'; |
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return dst; |
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} |
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EXPORT_SYMBOL_GPL(kstrdup_quotable); |
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|
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/* |
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* Returns allocated NULL-terminated string containing process |
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* command line, with inter-argument NULLs replaced with spaces, |
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* and other special characters escaped. |
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*/ |
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char *kstrdup_quotable_cmdline(struct task_struct *task, gfp_t gfp) |
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{ |
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char *buffer, *quoted; |
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int i, res; |
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buffer = kmalloc(PAGE_SIZE, GFP_KERNEL); |
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if (!buffer) |
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return NULL; |
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res = get_cmdline(task, buffer, PAGE_SIZE - 1); |
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buffer[res] = '\0'; |
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|
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/* Collapse trailing NULLs, leave res pointing to last non-NULL. */ |
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while (--res >= 0 && buffer[res] == '\0') |
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; |
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|
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/* Replace inter-argument NULLs. */ |
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for (i = 0; i <= res; i++) |
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if (buffer[i] == '\0') |
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buffer[i] = ' '; |
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|
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/* Make sure result is printable. */ |
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quoted = kstrdup_quotable(buffer, gfp); |
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kfree(buffer); |
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return quoted; |
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} |
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EXPORT_SYMBOL_GPL(kstrdup_quotable_cmdline); |
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|
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/* |
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* Returns allocated NULL-terminated string containing pathname, |
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* with special characters escaped, able to be safely logged. If |
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* there is an error, the leading character will be "<". |
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*/ |
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char *kstrdup_quotable_file(struct file *file, gfp_t gfp) |
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{ |
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char *temp, *pathname; |
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|
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if (!file) |
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return kstrdup("<unknown>", gfp); |
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|
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/* We add 11 spaces for ' (deleted)' to be appended */ |
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temp = kmalloc(PATH_MAX + 11, GFP_KERNEL); |
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if (!temp) |
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return kstrdup("<no_memory>", gfp); |
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pathname = file_path(file, temp, PATH_MAX + 11); |
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if (IS_ERR(pathname)) |
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pathname = kstrdup("<too_long>", gfp); |
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else |
|
pathname = kstrdup_quotable(pathname, gfp); |
|
|
|
kfree(temp); |
|
return pathname; |
|
} |
|
EXPORT_SYMBOL_GPL(kstrdup_quotable_file); |
|
|
|
/** |
|
* kfree_strarray - free a number of dynamically allocated strings contained |
|
* in an array and the array itself |
|
* |
|
* @array: Dynamically allocated array of strings to free. |
|
* @n: Number of strings (starting from the beginning of the array) to free. |
|
* |
|
* Passing a non-NULL @array and @n == 0 as well as NULL @array are valid |
|
* use-cases. If @array is NULL, the function does nothing. |
|
*/ |
|
void kfree_strarray(char **array, size_t n) |
|
{ |
|
unsigned int i; |
|
|
|
if (!array) |
|
return; |
|
|
|
for (i = 0; i < n; i++) |
|
kfree(array[i]); |
|
kfree(array); |
|
} |
|
EXPORT_SYMBOL_GPL(kfree_strarray);
|
|
|