[PATCH v1 00/12] lib/string_helpers: get rid of ugly *_escape_mem_ascii() API

[PATCH v1 00/12] lib/string_helpers: get rid of ugly *_escape_mem_ascii() API

[Andy Shevchenko]

Get rid of ugly *_escape_mem_ascii() API since it's not flexible and
has the only single user. Provide better approach based on usage of the
string_escape_mem() with appropriate flags.

Test cases has been expanded accordingly to cover new functionality.

Andy Shevchenko (12):
  lib/string_helpers: Switch to use BIT() macro
  lib/string_helpers: Move ESCAPE_NP check inside 'else' branch in a
    loop
  lib/string_helpers: Introduce ESCAPE_NA for escaping non-ASCII
  lib/string_helpers: Introduce ESCAPE_NAP to escape non-ASCII and
    non-printable
  lib/string_helpers: Drop indentation level in string_escape_mem()
  lib/string_helpers: Allow to append additional characters to be
    escaped
  lib/test-string_helpers: Print flags in hexadecimal format
  lib/test-string_helpers: Get rid of trailing comma in terminators
  lib/test-string_helpers: Add test cases for new features
  nfsd: Avoid non-flexible API in seq_quote_mem()
  lib/string_helpers: Drop unused *_escape_mem_ascii()
  MAINTAINERS: Add myself as designated reviewer for generic string
    library

 MAINTAINERS                    |   8 ++
 fs/nfsd/nfs4state.c            |   8 +-
 fs/seq_file.c                  |  11 ---
 include/linux/seq_file.h       |   1 -
 include/linux/string_helpers.h |  31 ++++---
 lib/string_helpers.c           | 102 ++++++++++++---------
 lib/test-string_helpers.c      | 157 +++++++++++++++++++++++++++++----
 7 files changed, 235 insertions(+), 83 deletions(-)

-- 
2.30.2

[PATCH v1 01/12] lib/string_helpers: Switch to use BIT() macro

[Andy Shevchenko]

Switch to use BIT() macro for flag definitions. No changes implied.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 include/linux/string_helpers.h | 21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/include/linux/string_helpers.h b/include/linux/string_helpers.h
index fa06dcdc481e..bf01e24edd89 100644
--- a/include/linux/string_helpers.h
+++ b/include/linux/string_helpers.h
@@ -2,6 +2,7 @@
 #ifndef _LINUX_STRING_HELPERS_H_
 #define _LINUX_STRING_HELPERS_H_
 
+#include <linux/bits.h>
 #include <linux/ctype.h>
 #include <linux/types.h>
 
@@ -18,10 +19,10 @@ enum string_size_units {
 void string_get_size(u64 size, u64 blk_size, enum string_size_units units,
 		     char *buf, int len);
 
-#define UNESCAPE_SPACE		0x01
-#define UNESCAPE_OCTAL		0x02
-#define UNESCAPE_HEX		0x04
-#define UNESCAPE_SPECIAL	0x08
+#define UNESCAPE_SPACE		BIT(0)
+#define UNESCAPE_OCTAL		BIT(1)
+#define UNESCAPE_HEX		BIT(2)
+#define UNESCAPE_SPECIAL	BIT(3)
 #define UNESCAPE_ANY		\
 	(UNESCAPE_SPACE | UNESCAPE_OCTAL | UNESCAPE_HEX | UNESCAPE_SPECIAL)
 
@@ -42,15 +43,15 @@ static inline int string_unescape_any_inplace(char *buf)
 	return string_unescape_any(buf, buf, 0);
 }
 
-#define ESCAPE_SPACE		0x01
-#define ESCAPE_SPECIAL		0x02
-#define ESCAPE_NULL		0x04
-#define ESCAPE_OCTAL		0x08
+#define ESCAPE_SPACE		BIT(0)
+#define ESCAPE_SPECIAL		BIT(1)
+#define ESCAPE_NULL		BIT(2)
+#define ESCAPE_OCTAL		BIT(3)
 #define ESCAPE_ANY		\
 	(ESCAPE_SPACE | ESCAPE_OCTAL | ESCAPE_SPECIAL | ESCAPE_NULL)
-#define ESCAPE_NP		0x10
+#define ESCAPE_NP		BIT(4)
 #define ESCAPE_ANY_NP		(ESCAPE_ANY | ESCAPE_NP)
-#define ESCAPE_HEX		0x20
+#define ESCAPE_HEX		BIT(5)
 
 int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz,
 		unsigned int flags, const char *only);
-- 
2.30.2

[PATCH v1 02/12] lib/string_helpers: Move ESCAPE_NP check inside 'else' branch in a loop

[Andy Shevchenko]

Refactor code to have better readability by moving ESCAPE_NP handling
inside 'else' branch in the loop.

No functional change intended.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 lib/string_helpers.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/lib/string_helpers.c b/lib/string_helpers.c
index 7f2d5fbaf243..b10a18b4663b 100644
--- a/lib/string_helpers.c
+++ b/lib/string_helpers.c
@@ -452,10 +452,10 @@ 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.
+ *	2. The character is matched to the printable class, 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.
  *	   %ESCAPE_OCTAL and %ESCAPE_HEX are going last since they cover any
  *	   character. Note that they actually can't go together, otherwise
@@ -506,19 +506,22 @@ int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz,
 
 		/*
 		 * 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, when @flags has
+		 *	  %ESCAPE_NP 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.
 		 */
-		if ((flags & ESCAPE_NP && isprint(c)) ||
-		    (is_dict && !strchr(only, c))) {
+		if (is_dict && !strchr(only, c)) {
 			/* do nothing */
 		} else {
+			if (isprint(c) &&
+			    flags & ESCAPE_NP && escape_passthrough(c, &p, end))
+				continue;
+
 			if (flags & ESCAPE_SPACE && escape_space(c, &p, end))
 				continue;
 
-- 
2.30.2

[PATCH v1 03/12] lib/string_helpers: Introduce ESCAPE_NA for escaping non-ASCII

[Andy Shevchenko]

Some users may want to have an ASCII based filter, provided by
isascii() function. 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           | 21 +++++++++++++++++----
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/include/linux/string_helpers.h b/include/linux/string_helpers.h
index bf01e24edd89..d6cf6fe10f74 100644
--- a/include/linux/string_helpers.h
+++ b/include/linux/string_helpers.h
@@ -52,6 +52,7 @@ static inline int string_unescape_any_inplace(char *buf)
 #define ESCAPE_NP		BIT(4)
 #define ESCAPE_ANY_NP		(ESCAPE_ANY | ESCAPE_NP)
 #define ESCAPE_HEX		BIT(5)
+#define ESCAPE_NA		BIT(6)
 
 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 b10a18b4663b..d426163cb446 100644
--- a/lib/string_helpers.c
+++ b/lib/string_helpers.c
@@ -454,8 +454,8 @@ 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 class, if asked, and in
- *	   case of match it passes through to the output.
+ *	2. The character is matched to the printable or ASCII class, 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.
  *	   %ESCAPE_OCTAL and %ESCAPE_HEX are going last since they cover any
  *	   character. Note that they actually can't go together, otherwise
@@ -463,7 +463,7 @@ static bool escape_hex(unsigned char c, char **dst, char *end)
  *
  * 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 +482,18 @@ 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()
+ *
+ * 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).
+ * 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.
  *
  * Return:
  * The total size of the escaped output that would be generated for
@@ -510,6 +517,8 @@ int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz,
 		 *	  character under question
 		 *	- 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
@@ -522,6 +531,10 @@ int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz,
 			    flags & ESCAPE_NP && escape_passthrough(c, &p, end))
 				continue;
 
+			if (isascii(c) &&
+			    flags & ESCAPE_NA && escape_passthrough(c, &p, end))
+				continue;
+
 			if (flags & ESCAPE_SPACE && escape_space(c, &p, end))
 				continue;
 
-- 
2.30.2

[PATCH v1 04/12] lib/string_helpers: Introduce ESCAPE_NAP to escape non-ASCII and non-printable

[Andy Shevchenko]

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 d426163cb446..26e35018684f 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
@@ -527,6 +535,10 @@ int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz,
 		if (is_dict && !strchr(only, c)) {
 			/* do nothing */
 		} else {
+			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

[PATCH v1 05/12] lib/string_helpers: Drop indentation level in string_escape_mem()

[Andy Shevchenko]

The only one conditional is left on the upper level, move the rest
to the same level and drop indentation level. No functional changes.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 lib/string_helpers.c | 47 ++++++++++++++++++++++----------------------
 1 file changed, 23 insertions(+), 24 deletions(-)

diff --git a/lib/string_helpers.c b/lib/string_helpers.c
index 26e35018684f..8e58e2c6f83d 100644
--- a/lib/string_helpers.c
+++ b/lib/string_helpers.c
@@ -532,37 +532,36 @@ int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz,
 		 * In these cases we just pass through a character to the
 		 * output buffer.
 		 */
-		if (is_dict && !strchr(only, c)) {
-			/* do nothing */
-		} else {
-			if (isascii(c) && isprint(c) &&
-			    flags & ESCAPE_NAP && escape_passthrough(c, &p, end))
-				continue;
+		if (is_dict && !strchr(only, c) && escape_passthrough(c, &p, end))
+			continue;
 
-			if (isprint(c) &&
-			    flags & ESCAPE_NP && escape_passthrough(c, &p, end))
-				continue;
+		if (isascii(c) && isprint(c) &&
+		    flags & ESCAPE_NAP && escape_passthrough(c, &p, end))
+			continue;
 
-			if (isascii(c) &&
-			    flags & ESCAPE_NA && escape_passthrough(c, &p, end))
-				continue;
+		if (isprint(c) &&
+		    flags & ESCAPE_NP && escape_passthrough(c, &p, end))
+			continue;
 
-			if (flags & ESCAPE_SPACE && escape_space(c, &p, end))
-				continue;
+		if (isascii(c) &&
+		    flags & ESCAPE_NA && escape_passthrough(c, &p, end))
+			continue;
 
-			if (flags & ESCAPE_SPECIAL && escape_special(c, &p, end))
-				continue;
+		if (flags & ESCAPE_SPACE && escape_space(c, &p, end))
+			continue;
 
-			if (flags & ESCAPE_NULL && escape_null(c, &p, end))
-				continue;
+		if (flags & ESCAPE_SPECIAL && escape_special(c, &p, end))
+			continue;
 
-			/* ESCAPE_OCTAL and ESCAPE_HEX always go last */
-			if (flags & ESCAPE_OCTAL && escape_octal(c, &p, end))
-				continue;
+		if (flags & ESCAPE_NULL && escape_null(c, &p, end))
+			continue;
 
-			if (flags & ESCAPE_HEX && escape_hex(c, &p, end))
-				continue;
-		}
+		/* ESCAPE_OCTAL and ESCAPE_HEX always go last */
+		if (flags & ESCAPE_OCTAL && escape_octal(c, &p, end))
+			continue;
+
+		if (flags & ESCAPE_HEX && escape_hex(c, &p, end))
+			continue;
 
 		escape_passthrough(c, &p, end);
 	}
-- 
2.30.2

[PATCH v1 06/12] lib/string_helpers: Allow to append additional characters to be escaped

[Andy Shevchenko]

Introduce a new flag to append additional characters, passed in 'only'
parameter, to be escaped if they fall in the corresponding class.

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 811c6a627620..f8728ed4d563 100644
--- a/include/linux/string_helpers.h
+++ b/include/linux/string_helpers.h
@@ -54,6 +54,7 @@ static inline int string_unescape_any_inplace(char *buf)
 #define ESCAPE_HEX		BIT(5)
 #define ESCAPE_NA		BIT(6)
 #define ESCAPE_NAP		BIT(7)
+#define ESCAPE_APPEND		BIT(8)
 
 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 8e58e2c6f83d..c15aea7a82e9 100644
--- a/lib/string_helpers.c
+++ b/lib/string_helpers.c
@@ -493,6 +493,11 @@ static bool escape_hex(unsigned char c, char **dst, char *end)
  *		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).
@@ -513,9 +518,11 @@ 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:
@@ -531,19 +538,24 @@ int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz,
 		 *	  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 (is_dict && !strchr(only, c) && escape_passthrough(c, &p, end))
+		if (!(is_append || in_dict) && is_dict &&
+					  escape_passthrough(c, &p, end))
 			continue;
 
-		if (isascii(c) && isprint(c) &&
+		if (!(is_append && in_dict) && isascii(c) && isprint(c) &&
 		    flags & ESCAPE_NAP && escape_passthrough(c, &p, end))
 			continue;
 
-		if (isprint(c) &&
+		if (!(is_append && in_dict) && isprint(c) &&
 		    flags & ESCAPE_NP && escape_passthrough(c, &p, end))
 			continue;
 
-		if (isascii(c) &&
+		if (!(is_append && in_dict) && isascii(c) &&
 		    flags & ESCAPE_NA && escape_passthrough(c, &p, end))
 			continue;
 
-- 
2.30.2

[PATCH v1 07/12] lib/test-string_helpers: Print flags in hexadecimal format

[Andy Shevchenko]

Since flags are bitmapped, it's better to print them in hexadecimal format.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 lib/test-string_helpers.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/test-string_helpers.c b/lib/test-string_helpers.c
index 10360d4ea273..079fb12d59cc 100644
--- a/lib/test-string_helpers.c
+++ b/lib/test-string_helpers.c
@@ -19,7 +19,7 @@ static __init bool test_string_check_buf(const char *name, unsigned int flags,
 	if (q_real == q_test && !memcmp(out_test, out_real, q_test))
 		return true;
 
-	pr_warn("Test '%s' failed: flags = %u\n", name, flags);
+	pr_warn("Test '%s' failed: flags = %#x\n", name, flags);
 
 	print_hex_dump(KERN_WARNING, "Input: ", DUMP_PREFIX_NONE, 16, 1,
 		       in, p, true);
@@ -290,7 +290,7 @@ test_string_escape_overflow(const char *in, int p, unsigned int flags, const cha
 
 	q_real = string_escape_mem(in, p, NULL, 0, flags, esc);
 	if (q_real != q_test)
-		pr_warn("Test '%s' failed: flags = %u, osz = 0, expected %d, got %d\n",
+		pr_warn("Test '%s' failed: flags = %#x, osz = 0, expected %d, got %d\n",
 			name, flags, q_test, q_real);
 }
 
-- 
2.30.2

[PATCH v1 08/12] lib/test-string_helpers: Get rid of trailing comma in terminators

[Andy Shevchenko]

Terminators by definition shouldn't accept anything behind.
Make them robust by removing trailing commas.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 lib/test-string_helpers.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/lib/test-string_helpers.c b/lib/test-string_helpers.c
index 079fb12d59cc..3e2def9ccfac 100644
--- a/lib/test-string_helpers.c
+++ b/lib/test-string_helpers.c
@@ -136,7 +136,7 @@ static const struct test_string_2 escape0[] __initconst = {{
 		.flags = ESCAPE_SPACE | ESCAPE_HEX,
 	},{
 		/* terminator */
-	}},
+	}}
 },{
 	.in = "\\h\\\"\a\e\\",
 	.s1 = {{
@@ -150,7 +150,7 @@ static const struct test_string_2 escape0[] __initconst = {{
 		.flags = ESCAPE_SPECIAL | ESCAPE_HEX,
 	},{
 		/* terminator */
-	}},
+	}}
 },{
 	.in = "\eb \\C\007\"\x90\r]",
 	.s1 = {{
@@ -201,7 +201,7 @@ static const struct test_string_2 escape0[] __initconst = {{
 		.flags = ESCAPE_NP | ESCAPE_HEX,
 	},{
 		/* terminator */
-	}},
+	}}
 },{
 	/* terminator */
 }};
@@ -217,7 +217,7 @@ static const struct test_string_2 escape1[] __initconst = {{
 		.flags = ESCAPE_HEX,
 	},{
 		/* terminator */
-	}},
+	}}
 },{
 	.in = "\\h\\\"\a\e\\",
 	.s1 = {{
@@ -225,7 +225,7 @@ static const struct test_string_2 escape1[] __initconst = {{
 		.flags = ESCAPE_OCTAL,
 	},{
 		/* terminator */
-	}},
+	}}
 },{
 	.in = "\eb \\C\007\"\x90\r]",
 	.s1 = {{
@@ -233,7 +233,7 @@ static const struct test_string_2 escape1[] __initconst = {{
 		.flags = ESCAPE_OCTAL,
 	},{
 		/* terminator */
-	}},
+	}}
 },{
 	/* terminator */
 }};
-- 
2.30.2

[PATCH v1 09/12] lib/test-string_helpers: Add test cases for new features

[Andy Shevchenko]

We have got new flags and hence new features of string_escape_mem().
Add test cases for that.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 include/linux/string_helpers.h |   4 +
 lib/test-string_helpers.c      | 141 +++++++++++++++++++++++++++++++--
 2 files changed, 137 insertions(+), 8 deletions(-)

diff --git a/include/linux/string_helpers.h b/include/linux/string_helpers.h
index f8728ed4d563..9b0eca2badf2 100644
--- a/include/linux/string_helpers.h
+++ b/include/linux/string_helpers.h
@@ -26,6 +26,8 @@ void string_get_size(u64 size, u64 blk_size, enum string_size_units units,
 #define UNESCAPE_ANY		\
 	(UNESCAPE_SPACE | UNESCAPE_OCTAL | UNESCAPE_HEX | UNESCAPE_SPECIAL)
 
+#define UNESCAPE_ALL_MASK	GENMASK(3, 0)
+
 int string_unescape(char *src, char *dst, size_t size, unsigned int flags);
 
 static inline int string_unescape_inplace(char *buf, unsigned int flags)
@@ -56,6 +58,8 @@ static inline int string_unescape_any_inplace(char *buf)
 #define ESCAPE_NAP		BIT(7)
 #define ESCAPE_APPEND		BIT(8)
 
+#define ESCAPE_ALL_MASK		GENMASK(8, 0)
+
 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/test-string_helpers.c b/lib/test-string_helpers.c
index 3e2def9ccfac..2185d71704f0 100644
--- a/lib/test-string_helpers.c
+++ b/lib/test-string_helpers.c
@@ -202,11 +202,25 @@ static const struct test_string_2 escape0[] __initconst = {{
 	},{
 		/* terminator */
 	}}
+},{
+	.in = "\007 \eb\"\x90\xCF\r",
+	.s1 = {{
+		.out = "\007 \eb\"\\220\\317\r",
+		.flags = ESCAPE_OCTAL | ESCAPE_NA,
+	},{
+		.out = "\007 \eb\"\\x90\\xcf\r",
+		.flags = ESCAPE_HEX | ESCAPE_NA,
+	},{
+		.out = "\007 \eb\"\x90\xCF\r",
+		.flags = ESCAPE_NA,
+	},{
+		/* terminator */
+	}}
 },{
 	/* terminator */
 }};
 
-#define	TEST_STRING_2_DICT_1		"b\\ \t\r"
+#define	TEST_STRING_2_DICT_1		"b\\ \t\r\xCF"
 static const struct test_string_2 escape1[] __initconst = {{
 	.in = "\f\\ \n\r\t\v",
 	.s1 = {{
@@ -215,14 +229,38 @@ static const struct test_string_2 escape1[] __initconst = {{
 	},{
 		.out = "\f\\x5c\\x20\n\\x0d\\x09\v",
 		.flags = ESCAPE_HEX,
+	},{
+		.out = "\f\\134\\040\n\\015\\011\v",
+		.flags = ESCAPE_ANY | ESCAPE_APPEND,
+	},{
+		.out = "\\014\\134\\040\\012\\015\\011\\013",
+		.flags = ESCAPE_OCTAL | ESCAPE_APPEND | ESCAPE_NAP,
+	},{
+		.out = "\\x0c\\x5c\\x20\\x0a\\x0d\\x09\\x0b",
+		.flags = ESCAPE_HEX | ESCAPE_APPEND | ESCAPE_NAP,
+	},{
+		.out = "\f\\134\\040\n\\015\\011\v",
+		.flags = ESCAPE_OCTAL | ESCAPE_APPEND | ESCAPE_NA,
+	},{
+		.out = "\f\\x5c\\x20\n\\x0d\\x09\v",
+		.flags = ESCAPE_HEX | ESCAPE_APPEND | ESCAPE_NA,
 	},{
 		/* terminator */
 	}}
 },{
-	.in = "\\h\\\"\a\e\\",
+	.in = "\\h\\\"\a\xCF\e\\",
 	.s1 = {{
-		.out = "\\134h\\134\"\a\e\\134",
+		.out = "\\134h\\134\"\a\\317\e\\134",
 		.flags = ESCAPE_OCTAL,
+	},{
+		.out = "\\134h\\134\"\a\\317\e\\134",
+		.flags = ESCAPE_ANY | ESCAPE_APPEND,
+	},{
+		.out = "\\134h\\134\"\\007\\317\\033\\134",
+		.flags = ESCAPE_OCTAL | ESCAPE_APPEND | ESCAPE_NAP,
+	},{
+		.out = "\\134h\\134\"\a\\317\e\\134",
+		.flags = ESCAPE_OCTAL | ESCAPE_APPEND | ESCAPE_NA,
 	},{
 		/* terminator */
 	}}
@@ -234,6 +272,88 @@ static const struct test_string_2 escape1[] __initconst = {{
 	},{
 		/* terminator */
 	}}
+},{
+	.in = "\007 \eb\"\x90\xCF\r",
+	.s1 = {{
+		.out = "\007 \eb\"\x90\xCF\r",
+		.flags = ESCAPE_NA,
+	},{
+		.out = "\007 \eb\"\x90\xCF\r",
+		.flags = ESCAPE_SPACE | ESCAPE_NA,
+	},{
+		.out = "\007 \eb\"\x90\xCF\r",
+		.flags = ESCAPE_SPECIAL | ESCAPE_NA,
+	},{
+		.out = "\007 \eb\"\x90\xCF\r",
+		.flags = ESCAPE_SPACE | ESCAPE_SPECIAL | ESCAPE_NA,
+	},{
+		.out = "\007 \eb\"\x90\\317\r",
+		.flags = ESCAPE_OCTAL | ESCAPE_NA,
+	},{
+		.out = "\007 \eb\"\x90\\317\r",
+		.flags = ESCAPE_SPACE | ESCAPE_OCTAL | ESCAPE_NA,
+	},{
+		.out = "\007 \eb\"\x90\\317\r",
+		.flags = ESCAPE_SPECIAL | ESCAPE_OCTAL | ESCAPE_NA,
+	},{
+		.out = "\007 \eb\"\x90\\317\r",
+		.flags = ESCAPE_ANY | ESCAPE_NA,
+	},{
+		.out = "\007 \eb\"\x90\\xcf\r",
+		.flags = ESCAPE_HEX | ESCAPE_NA,
+	},{
+		.out = "\007 \eb\"\x90\\xcf\r",
+		.flags = ESCAPE_SPACE | ESCAPE_HEX | ESCAPE_NA,
+	},{
+		.out = "\007 \eb\"\x90\\xcf\r",
+		.flags = ESCAPE_SPECIAL | ESCAPE_HEX | ESCAPE_NA,
+	},{
+		.out = "\007 \eb\"\x90\\xcf\r",
+		.flags = ESCAPE_SPACE | ESCAPE_SPECIAL | ESCAPE_HEX | ESCAPE_NA,
+	},{
+		/* terminator */
+	}}
+},{
+	.in = "\007 \eb\"\x90\xCF\r",
+	.s1 = {{
+		.out = "\007 \eb\"\x90\xCF\r",
+		.flags = ESCAPE_NAP,
+	},{
+		.out = "\007 \eb\"\x90\xCF\\r",
+		.flags = ESCAPE_SPACE | ESCAPE_NAP,
+	},{
+		.out = "\007 \eb\"\x90\xCF\r",
+		.flags = ESCAPE_SPECIAL | ESCAPE_NAP,
+	},{
+		.out = "\007 \eb\"\x90\xCF\\r",
+		.flags = ESCAPE_SPACE | ESCAPE_SPECIAL | ESCAPE_NAP,
+	},{
+		.out = "\007 \eb\"\x90\\317\\015",
+		.flags = ESCAPE_OCTAL | ESCAPE_NAP,
+	},{
+		.out = "\007 \eb\"\x90\\317\\r",
+		.flags = ESCAPE_SPACE | ESCAPE_OCTAL | ESCAPE_NAP,
+	},{
+		.out = "\007 \eb\"\x90\\317\\015",
+		.flags = ESCAPE_SPECIAL | ESCAPE_OCTAL | ESCAPE_NAP,
+	},{
+		.out = "\007 \eb\"\x90\\317\r",
+		.flags = ESCAPE_ANY | ESCAPE_NAP,
+	},{
+		.out = "\007 \eb\"\x90\\xcf\\x0d",
+		.flags = ESCAPE_HEX | ESCAPE_NAP,
+	},{
+		.out = "\007 \eb\"\x90\\xcf\\r",
+		.flags = ESCAPE_SPACE | ESCAPE_HEX | ESCAPE_NAP,
+	},{
+		.out = "\007 \eb\"\x90\\xcf\\x0d",
+		.flags = ESCAPE_SPECIAL | ESCAPE_HEX | ESCAPE_NAP,
+	},{
+		.out = "\007 \eb\"\x90\\xcf\\r",
+		.flags = ESCAPE_SPACE | ESCAPE_SPECIAL | ESCAPE_HEX | ESCAPE_NAP,
+	},{
+		/* terminator */
+	}}
 },{
 	/* terminator */
 }};
@@ -315,8 +435,13 @@ static __init void test_string_escape(const char *name,
 		/* NULL injection */
 		if (flags & ESCAPE_NULL) {
 			in[p++] = '\0';
-			out_test[q_test++] = '\\';
-			out_test[q_test++] = '0';
+			/* '\0' passes isascii() test */
+			if (flags & ESCAPE_NA && !(flags & ESCAPE_APPEND && esc)) {
+				out_test[q_test++] = '\0';
+			} else {
+				out_test[q_test++] = '\\';
+				out_test[q_test++] = '0';
+			}
 		}
 
 		/* Don't try strings that have no output */
@@ -459,17 +584,17 @@ static int __init test_string_helpers_init(void)
 	unsigned int i;
 
 	pr_info("Running tests...\n");
-	for (i = 0; i < UNESCAPE_ANY + 1; i++)
+	for (i = 0; i < UNESCAPE_ALL_MASK + 1; i++)
 		test_string_unescape("unescape", i, false);
 	test_string_unescape("unescape inplace",
 			     get_random_int() % (UNESCAPE_ANY + 1), true);
 
 	/* Without dictionary */
-	for (i = 0; i < (ESCAPE_ANY_NP | ESCAPE_HEX) + 1; i++)
+	for (i = 0; i < ESCAPE_ALL_MASK + 1; i++)
 		test_string_escape("escape 0", escape0, i, TEST_STRING_2_DICT_0);
 
 	/* With dictionary */
-	for (i = 0; i < (ESCAPE_ANY_NP | ESCAPE_HEX) + 1; i++)
+	for (i = 0; i < ESCAPE_ALL_MASK + 1; i++)
 		test_string_escape("escape 1", escape1, i, TEST_STRING_2_DICT_1);
 
 	/* Test string_get_size() */
-- 
2.30.2

[PATCH v1 10/12] nfsd: Avoid non-flexible API in seq_quote_mem()

[Andy Shevchenko]

string_escape_mem_ascii() followed by seq_escape_mem_ascii() is completely
non-flexible and shouldn't be exist from day 1.

Replace it with properly called string_escape_mem().

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 fs/nfsd/nfs4state.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index b517a8794400..15535589e5e4 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -2350,8 +2350,14 @@ static struct nfs4_client *get_nfsdfs_clp(struct inode *inode)
 
 static void seq_quote_mem(struct seq_file *m, char *data, int len)
 {
+	char *buf;
+	size_t size = seq_get_buf(m, &buf);
+	const char *only = "\"\\";
+	int ret;
+
 	seq_printf(m, "\"");
-	seq_escape_mem_ascii(m, data, len);
+	ret = string_escape_mem(data, len, buf, size, ESCAPE_HEX | ESCAPE_APPEND, only);
+	seq_commit(m, ret < size ? ret : -1);
 	seq_printf(m, "\"");
 }
 
-- 
2.30.2

Re: [PATCH v1 10/12] nfsd: Avoid non-flexible API in seq_quote_mem()

[Al Viro]

On Mon, May 03, 2021 at 11:49:05PM +0300, Andy Shevchenko wrote:
> string_escape_mem_ascii() followed by seq_escape_mem_ascii() is completely
> non-flexible and shouldn't be exist from day 1.
> 
> Replace it with properly called string_escape_mem().


NAKed-by: Al Viro <viro@zeniv.linux.org.uk>

Reason: use of seq_get_buf().  Which should have been static inline in
fs/seq_file.c, to start with.

Again, any new uses of seq_get_buf()/seq_commit() are grounds for automatic
NAK.  These interfaces *will* be withdrawn.

Re: [PATCH v1 10/12] nfsd: Avoid non-flexible API in seq_quote_mem()

[Andy Shevchenko]

On Mon, May 3, 2021 at 11:54 PM Al Viro <viro@zeniv.linux.org.uk> wrote:
>
> On Mon, May 03, 2021 at 11:49:05PM +0300, Andy Shevchenko wrote:
> > string_escape_mem_ascii() followed by seq_escape_mem_ascii() is completely
> > non-flexible and shouldn't be exist from day 1.
> >
> > Replace it with properly called string_escape_mem().
>
> NAKed-by: Al Viro <viro@zeniv.linux.org.uk>
>
> Reason: use of seq_get_buf().  Which should have been static inline in
> fs/seq_file.c, to start with.

I see.

> Again, any new uses of seq_get_buf()/seq_commit() are grounds for automatic
> NAK.  These interfaces *will* be withdrawn.

You meant that this is no way to get rid of this guy?
Any suggestions how to replace that API with a newer one?


-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v1 10/12] nfsd: Avoid non-flexible API in seq_quote_mem()

[Al Viro]

On Mon, May 03, 2021 at 11:56:41PM +0300, Andy Shevchenko wrote:
> On Mon, May 3, 2021 at 11:54 PM Al Viro <viro@zeniv.linux.org.uk> wrote:
> >
> > On Mon, May 03, 2021 at 11:49:05PM +0300, Andy Shevchenko wrote:
> > > string_escape_mem_ascii() followed by seq_escape_mem_ascii() is completely
> > > non-flexible and shouldn't be exist from day 1.
> > >
> > > Replace it with properly called string_escape_mem().
> >
> > NAKed-by: Al Viro <viro@zeniv.linux.org.uk>
> >
> > Reason: use of seq_get_buf().  Which should have been static inline in
> > fs/seq_file.c, to start with.
> 
> I see.
> 
> > Again, any new uses of seq_get_buf()/seq_commit() are grounds for automatic
> > NAK.  These interfaces *will* be withdrawn.
> 
> You meant that this is no way to get rid of this guy?
> Any suggestions how to replace that API with a newer one?

seq_escape_mem(), perhaps?

Re: [PATCH v1 10/12] nfsd: Avoid non-flexible API in seq_quote_mem()

[Andy Shevchenko]

On Tue, May 4, 2021 at 12:09 AM Al Viro <viro@zeniv.linux.org.uk> wrote:
> On Mon, May 03, 2021 at 11:56:41PM +0300, Andy Shevchenko wrote:
> > On Mon, May 3, 2021 at 11:54 PM Al Viro <viro@zeniv.linux.org.uk> wrote:
> > >
> > > On Mon, May 03, 2021 at 11:49:05PM +0300, Andy Shevchenko wrote:
> > > > string_escape_mem_ascii() followed by seq_escape_mem_ascii() is completely
> > > > non-flexible and shouldn't be exist from day 1.
> > > >
> > > > Replace it with properly called string_escape_mem().
> > >
> > > NAKed-by: Al Viro <viro@zeniv.linux.org.uk>
> > >
> > > Reason: use of seq_get_buf().  Which should have been static inline in
> > > fs/seq_file.c, to start with.
> >
> > I see.
> >
> > > Again, any new uses of seq_get_buf()/seq_commit() are grounds for automatic
> > > NAK.  These interfaces *will* be withdrawn.
> >
> > You meant that this is no way to get rid of this guy?
> > Any suggestions how to replace that API with a newer one?
>
> seq_escape_mem(), perhaps?

I think I have a better idea. What about adding seq_escape_with_flags()
and seq_escape() --> seq_escape_with_flags(..., ESCAPE_OCTAL, ...) ?

Would it work for you?

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v1 10/12] nfsd: Avoid non-flexible API in seq_quote_mem()

[Andy Shevchenko]

On Tue, May 4, 2021 at 12:11 AM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
> On Tue, May 4, 2021 at 12:09 AM Al Viro <viro@zeniv.linux.org.uk> wrote:
> > On Mon, May 03, 2021 at 11:56:41PM +0300, Andy Shevchenko wrote:
> > > On Mon, May 3, 2021 at 11:54 PM Al Viro <viro@zeniv.linux.org.uk> wrote:

...

> > > Any suggestions how to replace that API with a newer one?
> >
> > seq_escape_mem(), perhaps?
>
> I think I have a better idea. What about adding seq_escape_with_flags()
> and seq_escape() --> seq_escape_with_flags(..., ESCAPE_OCTAL, ...) ?
>
> Would it work for you?

Ah, it wouldn't work for the user, because it wants to pass the buffer size.
Okay, I'll take your suggestion, thanks!

-- 
With Best Regards,
Andy Shevchenko

[PATCH v1 11/12] lib/string_helpers: Drop unused *_escape_mem_ascii()

[Andy Shevchenko]

There are no more users of the seq_escape_mem_ascii()
followed by string_escape_mem_ascii().

Remove them for good.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 fs/seq_file.c                  | 11 -----------
 include/linux/seq_file.h       |  1 -
 include/linux/string_helpers.h |  3 ---
 lib/string_helpers.c           | 19 -------------------
 4 files changed, 34 deletions(-)

diff --git a/fs/seq_file.c b/fs/seq_file.c
index 5059248f2d64..f7956b299408 100644
--- a/fs/seq_file.c
+++ b/fs/seq_file.c
@@ -376,17 +376,6 @@ void seq_escape(struct seq_file *m, const char *s, const char *esc)
 }
 EXPORT_SYMBOL(seq_escape);
 
-void seq_escape_mem_ascii(struct seq_file *m, const char *src, size_t isz)
-{
-	char *buf;
-	size_t size = seq_get_buf(m, &buf);
-	int ret;
-
-	ret = string_escape_mem_ascii(src, isz, buf, size);
-	seq_commit(m, ret < size ? ret : -1);
-}
-EXPORT_SYMBOL(seq_escape_mem_ascii);
-
 void seq_vprintf(struct seq_file *m, const char *f, va_list args)
 {
 	int len;
diff --git a/include/linux/seq_file.h b/include/linux/seq_file.h
index 723b1fa1177e..adf62aa9c6c5 100644
--- a/include/linux/seq_file.h
+++ b/include/linux/seq_file.h
@@ -127,7 +127,6 @@ void seq_put_hex_ll(struct seq_file *m, const char *delimiter,
 		    unsigned long long v, unsigned int width);
 
 void seq_escape(struct seq_file *m, const char *s, const char *esc);
-void seq_escape_mem_ascii(struct seq_file *m, const char *src, size_t isz);
 
 void seq_hex_dump(struct seq_file *m, const char *prefix_str, int prefix_type,
 		  int rowsize, int groupsize, const void *buf, size_t len,
diff --git a/include/linux/string_helpers.h b/include/linux/string_helpers.h
index 9b0eca2badf2..68189c4a2eb1 100644
--- a/include/linux/string_helpers.h
+++ b/include/linux/string_helpers.h
@@ -63,9 +63,6 @@ static inline int string_unescape_any_inplace(char *buf)
 int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz,
 		unsigned int flags, const char *only);
 
-int string_escape_mem_ascii(const char *src, size_t isz, char *dst,
-					size_t osz);
-
 static inline int string_escape_mem_any_np(const char *src, size_t isz,
 		char *dst, size_t osz, const char *only)
 {
diff --git a/lib/string_helpers.c b/lib/string_helpers.c
index c15aea7a82e9..5a35c7e16e96 100644
--- a/lib/string_helpers.c
+++ b/lib/string_helpers.c
@@ -582,25 +582,6 @@ int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz,
 }
 EXPORT_SYMBOL(string_escape_mem);
 
-int string_escape_mem_ascii(const char *src, size_t isz, char *dst,
-					size_t osz)
-{
-	char *p = dst;
-	char *end = p + osz;
-
-	while (isz--) {
-		unsigned char c = *src++;
-
-		if (!isprint(c) || !isascii(c) || c == '"' || c == '\\')
-			escape_hex(c, &p, end);
-		else
-			escape_passthrough(c, &p, end);
-	}
-
-	return p - dst;
-}
-EXPORT_SYMBOL(string_escape_mem_ascii);
-
 /*
  * Return an allocated string that has been escaped of special characters
  * and double quotes, making it safe to log in quotes.
-- 
2.30.2

[PATCH v1 12/12] MAINTAINERS: Add myself as designated reviewer for generic string library

[Andy Shevchenko]

Add myself as designated reviewer for generic string library.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 MAINTAINERS | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 1783372a608a..2c5797fc462c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7650,6 +7650,14 @@ L:	linux-input@vger.kernel.org
 S:	Maintained
 F:	drivers/input/touchscreen/resistive-adc-touch.c
 
+GENERIC STRING LIBRARY
+R:	Andy Shevchenko <andy@kernel.org>
+S:	Maintained
+F:	lib/string.c
+F:	lib/string_helpers.c
+F:	lib/test_string.c
+F:	lib/test-string_helpers.c
+
 GENERIC UIO DRIVER FOR PCI DEVICES
 M:	"Michael S. Tsirkin" <mst@redhat.com>
 L:	kvm@vger.kernel.org
-- 
2.30.2