diff options
Diffstat (limited to 'lib/string_helpers.c')
| -rw-r--r-- | lib/string_helpers.c | 102 |
1 files changed, 61 insertions, 41 deletions
diff --git a/lib/string_helpers.c b/lib/string_helpers.c index 7f2d5fbaf243..5a35c7e16e96 100644 --- a/lib/string_helpers.c +++ b/lib/string_helpers.c @@ -452,18 +452,20 @@ static bool escape_hex(unsigned char c, char **dst, char *end) * The process of escaping byte buffer includes several parts. They are applied * in the following sequence. * - * 1. 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 not matched to the one from @only string and thus + * 1. The character is not matched to the one from @only string and thus * must go as-is to the output. - * 3. The character is checked if it falls into the class given by @flags. + * 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 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. * * Caller must provide valid source and destination pointers. Be aware that * destination buffer will not be NULL-terminated, thus caller have to append - * it if needs. The supported flags are:: + * it if needs. The supported flags are:: * * %ESCAPE_SPACE: (special white space, not space itself) * '\f' - form feed @@ -482,11 +484,27 @@ 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() + * %ESCAPE_NAP: + * escape only non-printable or non-ascii characters + * %ESCAPE_APPEND: + * append characters from @only to be escaped by the given classes + * + * %ESCAPE_APPEND would help to pass additional characters to the escaped, when + * one of %ESCAPE_NP, %ESCAPE_NA, or %ESCAPE_NAP is provided. + * + * 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 @@ -500,67 +518,69 @@ int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz, char *p = dst; char *end = p + osz; bool is_dict = only && *only; + bool is_append = flags & ESCAPE_APPEND; while (isz--) { unsigned char c = *src++; + bool in_dict = is_dict && strchr(only, c); /* * Apply rules in the following sequence: - * - the character is printable, when @flags has - * %ESCAPE_NP bit set * - 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 + * %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 * output buffer. + * + * When %ESCAPE_APPEND is passed, the characters from @only + * have been excluded from the %ESCAPE_NAP, %ESCAPE_NP, and + * %ESCAPE_NA cases. */ - if ((flags & ESCAPE_NP && isprint(c)) || - (is_dict && !strchr(only, c))) { - /* do nothing */ - } else { - if (flags & ESCAPE_SPACE && escape_space(c, &p, end)) - continue; + if (!(is_append || in_dict) && is_dict && + escape_passthrough(c, &p, end)) + continue; - if (flags & ESCAPE_SPECIAL && escape_special(c, &p, end)) - continue; + if (!(is_append && in_dict) && isascii(c) && isprint(c) && + flags & ESCAPE_NAP && escape_passthrough(c, &p, end)) + continue; - if (flags & ESCAPE_NULL && escape_null(c, &p, end)) - continue; + if (!(is_append && in_dict) && isprint(c) && + flags & ESCAPE_NP && escape_passthrough(c, &p, end)) + continue; - /* ESCAPE_OCTAL and ESCAPE_HEX always go last */ - if (flags & ESCAPE_OCTAL && escape_octal(c, &p, end)) - continue; + if (!(is_append && in_dict) && isascii(c) && + flags & ESCAPE_NA && escape_passthrough(c, &p, end)) + continue; - if (flags & ESCAPE_HEX && escape_hex(c, &p, end)) - continue; - } + if (flags & ESCAPE_SPACE && escape_space(c, &p, end)) + continue; - escape_passthrough(c, &p, end); - } + if (flags & ESCAPE_SPECIAL && escape_special(c, &p, end)) + continue; - return p - dst; -} -EXPORT_SYMBOL(string_escape_mem); + if (flags & ESCAPE_NULL && escape_null(c, &p, end)) + continue; -int string_escape_mem_ascii(const char *src, size_t isz, char *dst, - size_t osz) -{ - char *p = dst; - char *end = p + osz; + /* ESCAPE_OCTAL and ESCAPE_HEX always go last */ + if (flags & ESCAPE_OCTAL && escape_octal(c, &p, end)) + continue; - while (isz--) { - unsigned char c = *src++; + if (flags & ESCAPE_HEX && escape_hex(c, &p, end)) + continue; - if (!isprint(c) || !isascii(c) || c == '"' || c == '\\') - escape_hex(c, &p, end); - else - escape_passthrough(c, &p, end); + escape_passthrough(c, &p, end); } return p - dst; } -EXPORT_SYMBOL(string_escape_mem_ascii); +EXPORT_SYMBOL(string_escape_mem); /* * Return an allocated string that has been escaped of special characters |