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authorDavid Brownell <david-b@pacbell.net>2008-05-01 07:34:42 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2008-05-01 11:03:59 -0400
commit34990cf702bdf2b4964e0629dab4af7669f8b2c5 (patch)
tree33ec40ee97be1a9a6b3565dcf49d1dcffff191f9
parent7dffa3c673fbcf835cd7be80bb4aec8ad3f51168 (diff)
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: David Brownell <dbrownell@users.sourceforge.net> Acked-by: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/string.h2
-rw-r--r--lib/string.c27
2 files changed, 29 insertions, 0 deletions
diff --git a/include/linux/string.h b/include/linux/string.h
index c5d3fcad7b57..efdc44593b52 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -109,5 +109,7 @@ extern void *kmemdup(const void *src, size_t len, gfp_t gfp);
109extern char **argv_split(gfp_t gfp, const char *str, int *argcp); 109extern char **argv_split(gfp_t gfp, const char *str, int *argcp);
110extern void argv_free(char **argv); 110extern void argv_free(char **argv);
111 111
112extern bool sysfs_streq(const char *s1, const char *s2);
113
112#endif 114#endif
113#endif /* _LINUX_STRING_H_ */ 115#endif /* _LINUX_STRING_H_ */
diff --git a/lib/string.c b/lib/string.c
index 5efafed3d6b6..b19b87af65a3 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -493,6 +493,33 @@ char *strsep(char **s, const char *ct)
493EXPORT_SYMBOL(strsep); 493EXPORT_SYMBOL(strsep);
494#endif 494#endif
495 495
496/**
497 * sysfs_streq - return true if strings are equal, modulo trailing newline
498 * @s1: one string
499 * @s2: another string
500 *
501 * This routine returns true iff two strings are equal, treating both
502 * NUL and newline-then-NUL as equivalent string terminations. It's
503 * geared for use with sysfs input strings, which generally terminate
504 * with newlines but are compared against values without newlines.
505 */
506bool sysfs_streq(const char *s1, const char *s2)
507{
508 while (*s1 && *s1 == *s2) {
509 s1++;
510 s2++;
511 }
512
513 if (*s1 == *s2)
514 return true;
515 if (!*s1 && *s2 == '\n' && !s2[1])
516 return true;
517 if (*s1 == '\n' && !s1[1] && !*s2)
518 return true;
519 return false;
520}
521EXPORT_SYMBOL(sysfs_streq);
522
496#ifndef __HAVE_ARCH_MEMSET 523#ifndef __HAVE_ARCH_MEMSET
497/** 524/**
498 * memset - Fill a region of memory with the given value 525 * memset - Fill a region of memory with the given value