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Commit 34990cf7 authored by David Brownell's avatar David Brownell Committed by Linus Torvalds
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Add a new sysfs_streq() string comparison function 



Add a new sysfs_streq() string comparison function, which ignores
the trailing newlines found in sysfs inputs.  By example:

	sysfs_streq("a", "b")	==> false
	sysfs_streq("a", "a")	==> true
	sysfs_streq("a", "a\n")	==> true
	sysfs_streq("a\n", "a")	==> true

This is intended to simplify parsing of sysfs inputs, letting them
avoid the need to manually strip off newlines from inputs.

Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Acked-by: default avatarGreg KH <greg@kroah.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7dffa3c6

include/linux/string.h

+2 −0
Original line number Original line Diff line number Diff line
@@ -109,5 +109,7 @@ extern void *kmemdup(const void *src, size_t len, gfp_t gfp); 
extern char **argv_split(gfp_t gfp, const char *str, int *argcp);

extern char **argv_split(gfp_t gfp, const char *str, int *argcp);

extern void argv_free(char **argv);

extern void argv_free(char **argv);





extern bool sysfs_streq(const char *s1, const char *s2);



#endif

#endif

#endif /* _LINUX_STRING_H_ */
 
#endif /* _LINUX_STRING_H_ */

lib/string.c

+27 −0
Original line number Original line Diff line number Diff line
@@ -493,6 +493,33 @@ char *strsep(char **s, const char *ct) 
EXPORT_SYMBOL(strsep);

EXPORT_SYMBOL(strsep);

#endif

#endif





/**

 * sysfs_streq - return true if strings are equal, modulo trailing newline

 * @s1: one string

 * @s2: another string

 *

 * This routine returns true iff two strings are equal, treating both

 * NUL and newline-then-NUL as equivalent string terminations.  It's

 * geared for use with sysfs input strings, which generally terminate

 * with newlines but are compared against values without newlines.

 */

bool sysfs_streq(const char *s1, const char *s2)

{

	while (*s1 && *s1 == *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_streq);



#ifndef __HAVE_ARCH_MEMSET

#ifndef __HAVE_ARCH_MEMSET

/**

/**

 * memset - Fill a region of memory with the given value

 * memset - Fill a region of memory with the given value