The patch titled
Subject: lib/string_helpers: introduce ESCAPE_NAP to escape non-ASCII and non-printable
has been added to the -mm tree. Its filename is
lib-string_helpers-introduce-escape_nap-to-escape-non-ascii-and-non-printable.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/lib-string_helpers-introduce-escape_nap-to-escape-non-ascii-and-non-printable.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/lib-string_helpers-introduce-escape_nap-to-escape-non-ascii-and-non-printable.patch
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------------------------------------------------------
From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Subject: lib/string_helpers: introduce ESCAPE_NAP to escape non-ASCII and non-printable
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.
Link: https://lkml.kernel.org/r/20210504180819.73127-6-andriy.shevchenko@xxxxxxxxxxxxxxx
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Chuck Lever <chuck.lever@xxxxxxxxxx>
Cc: "J. Bruce Fields" <bfields@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/string_helpers.h | 1 +
lib/string_helpers.c | 20 ++++++++++++++++----
2 files changed, 17 insertions(+), 4 deletions(-)
--- a/include/linux/string_helpers.h~lib-string_helpers-introduce-escape_nap-to-escape-non-ascii-and-non-printable
+++ a/include/linux/string_helpers.h
@@ -53,6 +53,7 @@ static inline int string_unescape_any_in
#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);
--- a/lib/string_helpers.c~lib-string_helpers-introduce-escape_nap-to-escape-non-ascii-and-non-printable
+++ a/lib/string_helpers.c
@@ -454,9 +454,11 @@ static bool escape_hex(unsigned char c,
*
* 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,
* '\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, s
* 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, s
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;
_
Patches currently in -mm which might be from andriy.shevchenko@xxxxxxxxxxxxxxx are
lib-string_helpers-switch-to-use-bit-macro.patch
lib-string_helpers-move-escape_np-check-inside-else-branch-in-a-loop.patch
lib-string_helpers-drop-indentation-level-in-string_escape_mem.patch
lib-string_helpers-introduce-escape_na-for-escaping-non-ascii.patch
lib-string_helpers-introduce-escape_nap-to-escape-non-ascii-and-non-printable.patch
lib-string_helpers-allow-to-append-additional-characters-to-be-escaped.patch
lib-test-string_helpers-print-flags-in-hexadecimal-format.patch
lib-test-string_helpers-get-rid-of-trailing-comma-in-terminators.patch
lib-test-string_helpers-add-test-cases-for-new-features.patch
maintainers-add-myself-as-designated-reviewer-for-generic-string-library.patch
seq_file-introduce-seq_escape_mem.patch
seq_file-add-seq_escape_str-as-replica-of-string_escape_str.patch
seq_file-convert-seq_escape-to-use-seq_escape_str.patch
nfsd-avoid-non-flexible-api-in-seq_quote_mem.patch
seq_file-drop-unused-_escape_mem_ascii.patch
