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![Andy Shevchenko](/assets/img/avatar_default.png)
There are several places in kernel where modules unescapes input to convert C-Style Escape Sequences into byte codes. The patch provides generic implementation of such approach. Test cases are also included into the patch. [akpm@linux-foundation.org: clarify comment] [akpm@linux-foundation.org: export get_random_int() to modules] Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Samuel Thibault <samuel.thibault@ens-lyon.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jason Baron <jbaron@redhat.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: William Hubbs <w.d.hubbs@gmail.com> Cc: Chris Brannon <chris@the-brannons.com> Cc: Kirk Reiser <kirk@braille.uwo.ca> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
201 lines
3.6 KiB
C
201 lines
3.6 KiB
C
/*
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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/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 *units_10[] = { "B", "kB", "MB", "GB", "TB", "PB",
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"EB", "ZB", "YB", NULL};
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static const char *units_2[] = {"B", "KiB", "MiB", "GiB", "TiB", "PiB",
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"EiB", "ZiB", "YiB", NULL };
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static const char **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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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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