Hard to say where should live, but lib/strings.c seemed fair.
See the appended patch. I made it not care which string has
newline termination, since caring seems very error-prone.
- Dave
========= CUT HERE
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>
---
include/linux/string.h | 2 ++
lib/string.c | 27 +++++++++++++++++++++++++++
2 files changed, 29 insertions(+)
--- g26.orig/include/linux/string.h 2008-04-29 05:45:53.000000000 -0700
+++ g26/include/linux/string.h 2008-04-29 05:55:14.000000000 -0700
@@ -109,5 +109,7 @@ extern void *kmemdup(const void *src, si
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_ */
--- g26.orig/lib/string.c 2008-04-29 05:15:52.000000000 -0700
+++ g26/lib/string.c 2008-04-29 05:55:32.000000000 -0700
@@ -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
--
