Commit 94df2904 authored Jun 25, 2015 by Rasmus Villemoes Committed by Linus Torvalds Jun 25, 2015

lib/string.c: introduce strreplace()



Strings are sometimes sanitized by replacing a certain character (often
'/') by another (often '!').  In a few places, this is done the same way
Schlemiel the Painter would do it.  Others are slightly smarter but still
do multiple strchr() calls.  Introduce strreplace() to do this using a
single function call and a single pass over the string.

One would expect the return value to be one of three things: void, s, or
the number of replacements made.  I chose the fourth, returning a pointer
to the end of the string.  This is more likely to be useful (for example
allowing the caller to avoid a strlen call).

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Neil Brown <neilb@suse.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 9d2a8da0

include/linux/string.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -111,6 +111,7 @@ extern int memcmp(const void ,const void ,__kernel_size_t);
		extern void * memchr(const void *,int,__kernel_size_t);
		#endif
		void memchr_inv(const void s, int c, size_t n);
		char strreplace(char s, char old, char new);

		extern void kfree_const(const void *x);

lib/string.c

+17 −0

Original line number	Diff line number	Diff line
		@@ -849,3 +849,20 @@ void memchr_inv(const void start, int c, size_t bytes)
		return check_bytes8(start, value, bytes % 8);
		}
		EXPORT_SYMBOL(memchr_inv);

		/**
		* strreplace - Replace all occurrences of character in string.
		* @s: The string to operate on.
		* @old: The character being replaced.
		* @new: The character @old is replaced with.
		*
		* Returns pointer to the nul byte at the end of @s.
		*/
		char strreplace(char s, char old, char new)
		{
		for (; *s; ++s)
		if (*s == old)
		*s = new;
		return s;
		}
		EXPORT_SYMBOL(strreplace);

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