Some users may want to have an ASCII based filter for printable only characters, provided by conjunction of isascii() and isprint() functions. Here is the addition of a such. Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> --- include/linux/string_helpers.h | 1 + lib/string_helpers.c | 20 ++++++++++++++++---- 2 files changed, 17 insertions(+), 4 deletions(-) diff --git a/include/linux/string_helpers.h b/include/linux/string_helpers.h index d6cf6fe10f74..811c6a627620 100644 --- a/include/linux/string_helpers.h +++ b/include/linux/string_helpers.h @@ -53,6 +53,7 @@ static inline int string_unescape_any_inplace(char *buf) #define ESCAPE_ANY_NP (ESCAPE_ANY | ESCAPE_NP) #define ESCAPE_HEX BIT(5) #define ESCAPE_NA BIT(6) +#define ESCAPE_NAP BIT(7) int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz, unsigned int flags, const char *only); diff --git a/lib/string_helpers.c b/lib/string_helpers.c index a963404b8c16..ceca5fbbd92c 100644 --- a/lib/string_helpers.c +++ b/lib/string_helpers.c @@ -454,9 +454,11 @@ 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 or ASCII class, if asked, + * 2. The character is matched to the printable and ASCII classes, 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. + * 3. The character is matched to the printable or ASCII class, if asked, + * and in case of match it passes through to the output. + * 4. 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 * %ESCAPE_HEX will be ignored. @@ -489,11 +491,15 @@ static bool escape_hex(unsigned char c, char **dst, char *end) * '\xHH' - byte with hexadecimal value HH (2 digits) * %ESCAPE_NA: * escape only non-ascii characters, checked by isascii() + * %ESCAPE_NAP: + * escape only non-printable or non-ascii characters * - * 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). + * One notable caveat, the %ESCAPE_NAP, %ESCAPE_NP and %ESCAPE_NA have the + * higher priority than the rest of the flags (%ESCAPE_NAP is the highest). * 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. + * %ESCAPE_NAP can utilize %ESCAPE_SPACE or %ESCAPE_SPECIAL in addition to + * the above. * * Return: * The total size of the escaped output that would be generated for @@ -515,6 +521,8 @@ int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz, * Apply rules in the following sequence: * - the @only string is supplied and does not contain a * character under question + * - the character is printable and ASCII, when @flags has + * %ESCAPE_NAP bit set * - the character is printable, when @flags has * %ESCAPE_NP bit set * - the character is ASCII, when @flags has @@ -528,6 +536,10 @@ int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz, escape_passthrough(c, &p, end)) continue; + if (isascii(c) && isprint(c) && + flags & ESCAPE_NAP && escape_passthrough(c, &p, end)) + continue; + if (isprint(c) && flags & ESCAPE_NP && escape_passthrough(c, &p, end)) continue; -- 2.30.2
