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* [PATCH] lib/string: Introduce sysfs_streqcase
@ 2021-04-07  6:14 Gioh Kim
  2021-04-07 20:06 ` Nick Desaulniers
  0 siblings, 1 reply; 10+ messages in thread
From: Gioh Kim @ 2021-04-07  6:14 UTC (permalink / raw)
  To: linux-kernel
  Cc: ndesaulniers, dan.j.williams, andreyknvl, laniel_francis,
	keescook, dja, akpm, Gioh Kim

As the name shows, it checks if strings are equal in case insensitive
manner.

For example, drivers/infiniband/ulp/rtrs/rtrs-clt-sysfs.c uses
strncasecmp to check that the input via sysfs is "mi". But it would
work even-if the input is "min-wrongcommand".

I found some more cases using strncasecmp to check the entire string
such as rtrs-clt-sysfs.c does. drivers/pnp/interface.c checks
"disable" command with strncasecmp but it would also work if the
command is "disable-wrong".

Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
---
 include/linux/string.h |  1 +
 lib/string.c           | 23 +++++++++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/include/linux/string.h b/include/linux/string.h
index 4fcfb56abcf5..36d00ff8013e 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -184,6 +184,7 @@ extern char **argv_split(gfp_t gfp, const char *str, int *argcp);
 extern void argv_free(char **argv);
 
 extern bool sysfs_streq(const char *s1, const char *s2);
+extern bool sysfs_streqcase(const char *s1, const char *s2);
 extern int kstrtobool(const char *s, bool *res);
 static inline int strtobool(const char *s, bool *res)
 {
diff --git a/lib/string.c b/lib/string.c
index 7548eb715ddb..5e6bc0d3d5c6 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -714,6 +714,29 @@ bool sysfs_streq(const char *s1, const char *s2)
 }
 EXPORT_SYMBOL(sysfs_streq);
 
+/**
+ * sysfs_streqcase - same to sysfs_streq and case insensitive
+ * @s1: one string
+ * @s2: another string
+ *
+ */
+bool sysfs_streqcase(const char *s1, const char *s2)
+{
+	while (*s1 && tolower(*s1) == tolower(*s2)) {
+		s1++;
+		s2++;
+	}
+
+	if (*s1 == *s2)
+		return true;
+	if (!*s1 && *s2 == '\n' && !s2[1])
+		return true;
+	if (*s1 == '\n' && !s1[1] && !*s2)
+		return true;
+	return false;
+}
+EXPORT_SYMBOL(sysfs_streqcase);
+
 /**
  * match_string - matches given string in an array
  * @array:	array of strings
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 10+ messages in thread
* [PATCH] lib/string: Introduce sysfs_streqcase
@ 2021-04-02  9:40 Gioh Kim
  2021-04-02 17:59   ` kernel test robot
  2021-04-02 18:17 ` Nick Desaulniers
  0 siblings, 2 replies; 10+ messages in thread
From: Gioh Kim @ 2021-04-02  9:40 UTC (permalink / raw)
  To: linux-kernel; +Cc: ndesaulniers, jinpu.wang, Gioh Kim

As the name shows, it checks if strings are equal in case insensitive
manner. I found some cases using strncasecmp to check the entire
strings and they would not work as intended.

For example, drivers/infiniband/ulp/rtrs/rtrs-clt-sysfs.c uses
strncasecmp to check that the input via sysfs is "mi". But it would
work even-if the input is "min-wrongcommand".
And also drivers/pnp/interface.c checks "disable" command with
strncasecmp but it would also work if the command is "disable-wrong".

Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
---
 lib/string.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/lib/string.c b/lib/string.c
index 7548eb715ddb..5e6bc0d3d5c6 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -714,6 +714,29 @@ bool sysfs_streq(const char *s1, const char *s2)
 }
 EXPORT_SYMBOL(sysfs_streq);
 
+/**
+ * sysfs_streqcase - same to sysfs_streq and case insensitive
+ * @s1: one string
+ * @s2: another string
+ *
+ */
+bool sysfs_streqcase(const char *s1, const char *s2)
+{
+	while (*s1 && tolower(*s1) == tolower(*s2)) {
+		s1++;
+		s2++;
+	}
+
+	if (*s1 == *s2)
+		return true;
+	if (!*s1 && *s2 == '\n' && !s2[1])
+		return true;
+	if (*s1 == '\n' && !s1[1] && !*s2)
+		return true;
+	return false;
+}
+EXPORT_SYMBOL(sysfs_streqcase);
+
 /**
  * match_string - matches given string in an array
  * @array:	array of strings
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 10+ messages in thread
end of thread, other threads:[~2021-04-08  7:26 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-04-07  6:14 [PATCH] lib/string: Introduce sysfs_streqcase Gioh Kim
2021-04-07 20:06 ` Nick Desaulniers
2021-04-08  7:25   ` Gioh Kim
  -- strict thread matches above, loose matches on Subject: below --
2021-04-02  9:40 Gioh Kim
2021-04-02 17:59 ` kernel test robot
2021-04-02 17:59   ` kernel test robot
2021-04-02 18:17 ` Nick Desaulniers
2021-04-02 18:23   ` Kees Cook
2021-04-02 19:43     ` Gioh Kim
2021-04-02 19:41   ` Gioh Kim

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