lib/string_helpers: clarify esc arg in string_escape_mem
The esc argument is used to reduce which characters will be escaped. For
example, using " " with ESCAPE_SPACE will not produce any escaped spaces.
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Mathias Krause <minipli@googlemail.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/lib/string_helpers.c b/lib/string_helpers.c
index c98ae81..0a307a9 100644
--- a/lib/string_helpers.c
+++ b/lib/string_helpers.c
@@ -410,7 +410,7 @@
* @dst: destination buffer (escaped)
* @osz: destination buffer size
* @flags: combination of the flags (bitwise OR):
- * %ESCAPE_SPACE:
+ * %ESCAPE_SPACE: (special white space, not space itself)
* '\f' - form feed
* '\n' - new line
* '\r' - carriage return
@@ -432,8 +432,10 @@
* all previous together
* %ESCAPE_HEX:
* '\xHH' - byte with hexadecimal value HH (2 digits)
- * @esc: NULL-terminated string of characters any of which, if found in
- * the source, has to be escaped
+ * @esc: NULL-terminated string containing characters used to limit
+ * the selected escape class. If characters are included in @esc
+ * that would not normally be escaped by the classes selected
+ * in @flags, they will be copied to @dst unescaped.
*
* Description:
* The process of escaping byte buffer includes several parts. They are applied
@@ -441,7 +443,7 @@
* 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 @esc string and thus
- * must go as is to the output.
+ * must go as-is 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
