lib/string_helpers: introduce generic string_unescape (16c7fa05) · Commits · 戴 / test

drivers/char/random.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -1485,6 +1485,7 @@ unsigned int get_random_int(void)

		return ret;
		}
		EXPORT_SYMBOL(get_random_int);

		/*
		* randomize_range() returns a start address such that

include/linux/string_helpers.h

+58 −0

Original line number	Diff line number	Diff line
		@@ -13,4 +13,62 @@ enum string_size_units {
		int string_get_size(u64 size, enum string_size_units units,
		char *buf, int len);

		#define UNESCAPE_SPACE 0x01
		#define UNESCAPE_OCTAL 0x02
		#define UNESCAPE_HEX 0x04
		#define UNESCAPE_SPECIAL 0x08
		#define UNESCAPE_ANY \
		(UNESCAPE_SPACE \| UNESCAPE_OCTAL \| UNESCAPE_HEX \| UNESCAPE_SPECIAL)

		/**
		* string_unescape - unquote characters in the given string
		* @src: source buffer (escaped)
		* @dst: destination buffer (unescaped)
		* @size: size of the destination buffer (0 to unlimit)
		* @flags: combination of the flags (bitwise OR):
		* %UNESCAPE_SPACE:
		* '\f' - form feed
		* '\n' - new line
		* '\r' - carriage return
		* '\t' - horizontal tab
		* '\v' - vertical tab
		* %UNESCAPE_OCTAL:
		* '\NNN' - byte with octal value NNN (1 to 3 digits)
		* %UNESCAPE_HEX:
		* '\xHH' - byte with hexadecimal value HH (1 to 2 digits)
		* %UNESCAPE_SPECIAL:
		* '\"' - double quote
		* '\\' - backslash
		* '\a' - alert (BEL)
		* '\e' - escape
		* %UNESCAPE_ANY:
		* all previous together
		*
		* Returns amount of characters processed to the destination buffer excluding
		* trailing '\0'.
		*
		* Because the size of the output will be the same as or less than the size of
		* the input, the transformation may be performed in place.
		*
		* Caller must provide valid source and destination pointers. Be aware that
		* destination buffer will always be NULL-terminated. Source string must be
		* NULL-terminated as well.
		*/
		int string_unescape(char src, char dst, size_t size, unsigned int flags);

		static inline int string_unescape_inplace(char *buf, unsigned int flags)
		{
		return string_unescape(buf, buf, 0, flags);
		}

		static inline int string_unescape_any(char src, char dst, size_t size)
		{
		return string_unescape(src, dst, size, UNESCAPE_ANY);
		}

		static inline int string_unescape_any_inplace(char *buf)
		{
		return string_unescape_any(buf, buf, 0);
		}

		#endif

lib/Kconfig.debug

+3 −0

Original line number	Diff line number	Diff line
		@@ -1463,5 +1463,8 @@ source "lib/Kconfig.kgdb"

		source "lib/Kconfig.kmemcheck"

		config TEST_STRING_HELPERS
		tristate "Test functions located in the string_helpers module at runtime"

		config TEST_KSTRTOX
		tristate "Test kstrto*() family of functions at runtime"

lib/Makefile

+3 −1

Original line number	Diff line number	Diff line
		@@ -22,8 +22,10 @@ lib-y += kobject.o klist.o

		obj-y += bcd.o div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \
		bust_spinlocks.o hexdump.o kasprintf.o bitmap.o scatterlist.o \
		string_helpers.o gcd.o lcm.o list_sort.o uuid.o flex_array.o \
		gcd.o lcm.o list_sort.o uuid.o flex_array.o \
		bsearch.o find_last_bit.o find_next_bit.o llist.o memweight.o kfifo.o
		obj-y += string_helpers.o
		obj-$(CONFIG_TEST_STRING_HELPERS) += test-string_helpers.o
		obj-y += kstrtox.o
		obj-$(CONFIG_TEST_KSTRTOX) += test-kstrtox.o

lib/string_helpers.c

+133 −0

Original line number	Diff line number	Diff line
		@@ -2,10 +2,12 @@
		* Helpers for formatting and printing strings
		*
		* Copyright 31 August 2008 James Bottomley
		* Copyright (C) 2013, Intel Corporation
		*/
		#include <linux/kernel.h>
		#include <linux/math64.h>
		#include <linux/export.h>
		#include <linux/ctype.h>
		#include <linux/string_helpers.h>

		/**
		@@ -66,3 +68,134 @@ int string_get_size(u64 size, const enum string_size_units units,
		return 0;
		}
		EXPORT_SYMBOL(string_get_size);

		static bool unescape_space(char src, char dst)
		{
		char p = dst, q = src;

		switch (*q) {
		case 'n':
		*p = '\n';
		break;
		case 'r':
		*p = '\r';
		break;
		case 't':
		*p = '\t';
		break;
		case 'v':
		*p = '\v';
		break;
		case 'f':
		*p = '\f';
		break;
		default:
		return false;
		}
		*dst += 1;
		*src += 1;
		return true;
		}

		static bool unescape_octal(char src, char dst)
		{
		char p = dst, q = src;
		u8 num;

		if (isodigit(*q) == 0)
		return false;

		num = (*q++) & 7;
		while (num < 32 && isodigit(q) && (q - src < 3)) {
		num <<= 3;
		num += (*q++) & 7;
		}
		*p = num;
		*dst += 1;
		*src = q;
		return true;
		}

		static bool unescape_hex(char src, char dst)
		{
		char p = dst, q = src;
		int digit;
		u8 num;

		if (*q++ != 'x')
		return false;

		num = digit = hex_to_bin(*q++);
		if (digit < 0)
		return false;

		digit = hex_to_bin(*q);
		if (digit >= 0) {
		q++;
		num = (num << 4) \| digit;
		}
		*p = num;
		*dst += 1;
		*src = q;
		return true;
		}

		static bool unescape_special(char src, char dst)
		{
		char p = dst, q = src;

		switch (*q) {
		case '\"':
		*p = '\"';
		break;
		case '\\':
		*p = '\\';
		break;
		case 'a':
		*p = '\a';
		break;
		case 'e':
		*p = '\e';
		break;
		default:
		return false;
		}
		*dst += 1;
		*src += 1;
		return true;
		}

		int string_unescape(char src, char dst, size_t size, unsigned int flags)
		{
		char *out = dst;

		while (*src && --size) {
		if (src[0] == '\\' && src[1] != '\0' && size > 1) {
		src++;
		size--;

		if (flags & UNESCAPE_SPACE &&
		unescape_space(&src, &out))
		continue;

		if (flags & UNESCAPE_OCTAL &&
		unescape_octal(&src, &out))
		continue;

		if (flags & UNESCAPE_HEX &&
		unescape_hex(&src, &out))
		continue;

		if (flags & UNESCAPE_SPECIAL &&
		unescape_special(&src, &out))
		continue;

		*out++ = '\\';
		}
		out++ = src++;
		}
		*out = '\0';

		return out - dst;
		}
		EXPORT_SYMBOL(string_unescape);

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