Commit a0809783 authored by Andy Shevchenko's avatar Andy Shevchenko Committed by Linus Torvalds
Browse files

lib/string_helpers: introduce ESCAPE_NA for escaping non-ASCII 

Some users may want to have an ASCII based filter, provided by isascii()
function.  Here is the addition of a such.

Link: https://lkml.kernel.org/r/20210504180819.73127-5-andriy.shevchenko@linux.intel.com


Signed-off-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7e5969ae

include/linux/string_helpers.h

+1 −0
Original line number Diff line number Diff line
@@ -52,6 +52,7 @@ static inline int string_unescape_any_inplace(char *buf) 
#define ESCAPE_NP		BIT(4)

#define ESCAPE_ANY_NP		(ESCAPE_ANY | ESCAPE_NP)

#define ESCAPE_HEX		BIT(5)

#define ESCAPE_NA		BIT(6)



int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz,

		unsigned int flags, const char *only);

lib/string_helpers.c

+17 −4
Original line number Diff line number Diff line
@@ -454,8 +454,8 @@ static bool escape_hex(unsigned char c, char **dst, char *end) 
 *

 *	1. The character is not matched to the one from @only string and thus

 *	   must go as-is to the output.

 *	2. The character is matched to the printable class, if asked, and in

 *	   case of match it passes through to the output.

 *	2. The character is matched to the printable or ASCII class, if asked,

 *	   and in case of match it passes through to the output.

 *	3. The character is checked if it falls into the class given by @flags.

 *	   %ESCAPE_OCTAL and %ESCAPE_HEX are going last since they cover any

 *	   character. Note that they actually can't go together, otherwise
@@ -482,11 +482,18 @@ static bool escape_hex(unsigned char c, char **dst, char *end) 
 *	%ESCAPE_ANY:

 *		all previous together

 *	%ESCAPE_NP:

 *		escape only non-printable characters (checked by isprint)

 *		escape only non-printable characters, checked by isprint()

 *	%ESCAPE_ANY_NP:

 *		all previous together

 *	%ESCAPE_HEX:

 *		'\xHH' - byte with hexadecimal value HH (2 digits)

 *	%ESCAPE_NA:

 *		escape only non-ascii characters, checked by isascii()

 *

 * One notable caveat, the %ESCAPE_NP and %ESCAPE_NA have higher priority

 * than the rest of the flags (%ESCAPE_NP is higher than %ESCAPE_NA).

 * It doesn't make much sense to use either of them without %ESCAPE_OCTAL

 * or %ESCAPE_HEX, because they cover most of the other character classes.

 *

 * Return:

 * The total size of the escaped output that would be generated for
@@ -510,6 +517,8 @@ int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz, 
		 *	  character under question

		 *	- the character is printable, when @flags has

		 *	  %ESCAPE_NP bit set

		 *	- the character is ASCII, when @flags has

		 *	  %ESCAPE_NA bit set

		 *	- the character doesn't fall into a class of symbols

		 *	  defined by given @flags

		 * In these cases we just pass through a character to the
@@ -523,6 +532,10 @@ int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz, 
		    flags & ESCAPE_NP && escape_passthrough(c, &p, end))

			continue;



		if (isascii(c) &&

		    flags & ESCAPE_NA && escape_passthrough(c, &p, end))

			continue;



		if (flags & ESCAPE_SPACE && escape_space(c, &p, end))

			continue;