Commit 34990cf7 authored by David Brownell's avatar David Brownell Committed by Linus Torvalds

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
...@@ -109,5 +109,7 @@ extern void *kmemdup(const void *src, size_t len, gfp_t gfp); ...@@ -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_ */
...@@ -493,6 +493,33 @@ char *strsep(char **s, const char *ct) ...@@ -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
......
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