From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: "J. Bruce Fields" <bfields@redhat.com>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org,
linux-fsdevel@vger.kernel.org
Cc: "J. Bruce Fields" <bfields@fieldses.org>,
Chuck Lever <chuck.lever@oracle.com>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Andy Shevchenko <andy@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>
Subject: [PATCH v2 05/14] lib/string_helpers: Introduce ESCAPE_NAP to escape non-ASCII and non-printable
Date: Tue, 4 May 2021 13:26:39 +0300 [thread overview]
Message-ID: <20210504102648.88057-6-andriy.shevchenko@linux.intel.com> (raw)
In-Reply-To: <20210504102648.88057-1-andriy.shevchenko@linux.intel.com>
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@linux.intel.com>
---
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
next prev parent reply other threads:[~2021-05-04 10:27 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-04 10:26 [PATCH v2 00/14] lib/string_helpers: get rid of ugly *_escape_mem_ascii() Andy Shevchenko
2021-05-04 10:26 ` [PATCH v2 01/14] lib/string_helpers: Switch to use BIT() macro Andy Shevchenko
2021-05-04 10:26 ` [PATCH v2 02/14] lib/string_helpers: Move ESCAPE_NP check inside 'else' branch in a loop Andy Shevchenko
2021-05-04 10:26 ` [PATCH v2 03/14] lib/string_helpers: Drop indentation level in string_escape_mem() Andy Shevchenko
2021-05-04 10:26 ` [PATCH v2 04/14] lib/string_helpers: Introduce ESCAPE_NA for escaping non-ASCII Andy Shevchenko
2021-05-04 10:26 ` Andy Shevchenko [this message]
2021-05-04 10:26 ` [PATCH v2 06/14] lib/string_helpers: Allow to append additional characters to be escaped Andy Shevchenko
2021-05-04 10:26 ` [PATCH v2 07/14] lib/test-string_helpers: Print flags in hexadecimal format Andy Shevchenko
2021-05-04 10:26 ` [PATCH v2 08/14] lib/test-string_helpers: Get rid of trailing comma in terminators Andy Shevchenko
2021-05-04 10:26 ` [PATCH v2 09/14] lib/test-string_helpers: Add test cases for new features Andy Shevchenko
2021-05-04 10:26 ` [PATCH v2 10/14] MAINTAINERS: Add myself as designated reviewer for generic string library Andy Shevchenko
2021-05-04 10:26 ` [PATCH v2 11/14] seq_file: Introduce seq_escape_mem() Andy Shevchenko
2021-05-04 10:26 ` [PATCH v2 12/14] seq_file: Replace seq_escape() with inliner Andy Shevchenko
2021-05-04 12:41 ` kernel test robot
2021-05-04 13:17 ` kernel test robot
2021-05-04 13:53 ` Andy Shevchenko
2021-05-04 15:54 ` kernel test robot
2021-05-04 16:26 ` Andy Shevchenko
2021-05-04 10:26 ` [PATCH v2 13/14] nfsd: Avoid non-flexible API in seq_quote_mem() Andy Shevchenko
2021-05-04 10:26 ` [PATCH v2 14/14] seq_file: Drop unused *_escape_mem_ascii() Andy Shevchenko
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