diff mbox series

[net-next,1/2] lib: string: add strreplace_nonalnum

Message ID 981d965e-b25b-be2b-2067-07aec5eafc7a@gmail.com
State Deferred
Delegated to: David Miller
Headers show
Series lib: string: add strreplace_nonalnum | expand

Commit Message

Heiner Kallweit March 3, 2019, 5:20 p.m. UTC 
Add a new function strreplace_nonalnum that replaces all
non-alphanumeric characters. Such functionality is needed e.g. when a
string is supposed to be used in a sysfs file name. If '\0' is given
as new character then non-alphanumeric characters are cut. 

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
 include/linux/string.h |  1 +
 lib/string.c           | 27 +++++++++++++++++++++++++++
 2 files changed, 28 insertions(+)
diff mbox series

Patch

diff --git a/include/linux/string.h b/include/linux/string.h
index 7927b875f..d827b0b0f 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -169,6 +169,7 @@  static inline void memcpy_flushcache(void *dst, const void *src, size_t cnt)
 #endif
 void *memchr_inv(const void *s, int c, size_t n);
 char *strreplace(char *s, char old, char new);
+char *strreplace_nonalnum(char *s, char new);
 
 extern void kfree_const(const void *x);
 
diff --git a/lib/string.c b/lib/string.c
index 38e4ca08e..f2b1baf96 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -1047,6 +1047,33 @@  char *strreplace(char *s, char old, char new)
 }
 EXPORT_SYMBOL(strreplace);
 
+/**
+ * strreplace_nonalnum - Replace all non-alphanumeric characters in a string.
+ * @s: The string to operate on.
+ * @new: The character non-alphanumeric characters are replaced with.
+ *
+ * If new is '\0' then non-alphanumeric characters are cut.
+ *
+ * Returns pointer to the nul byte at the end of the modified string.
+ */
+char *strreplace_nonalnum(char *s, char new)
+{
+	char *p = s;
+
+	for (; *s; ++s)
+		if (isalnum(*s)) {
+			if (p != s)
+				*p = *s;
+			++p;
+		} else if (new) {
+			*p++ = new;
+		}
+	*p = '\0';
+
+	return p;
+}
+EXPORT_SYMBOL(strreplace_nonalnum);
+
 void fortify_panic(const char *name)
 {
 	pr_emerg("detected buffer overflow in %s\n", name);