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| author | David Brownell <david-b@pacbell.net> | 2008-05-01 04:34:42 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-05-01 08:03:59 -0700 |
| commit | 34990cf702bdf2b4964e0629dab4af7669f8b2c5 (patch) | |
| tree | 33ec40ee97be1a9a6b3565dcf49d1dcffff191f9 | |
| parent | 7dffa3c673fbcf835cd7be80bb4aec8ad3f51168 (diff) | |
| download | linux-34990cf702bdf2b4964e0629dab4af7669f8b2c5.tar.bz2 | |
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.h | 2 | ||||
| -rw-r--r-- | lib/string.c | 27 |
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); extern char **argv_split(gfp_t gfp, const char *str, int *argcp); extern void argv_free(char **argv); +extern bool sysfs_streq(const char *s1, const char *s2); + #endif #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) EXPORT_SYMBOL(strsep); #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 /** * memset - Fill a region of memory with the given value |