Commit-ID: d5f1fb53353edc38da326445267c1df0c9676df2
Gitweb: http://git.kernel.org/tip/d5f1fb53353edc38da326445267c1df0c9676df2
Author: Li Zefan <lizf@xxxxxxxxxxxxxx>
AuthorDate: Thu, 14 Jan 2010 10:53:55 +0800
Committer: Steven Rostedt <rostedt@xxxxxxxxxxx>
CommitDate: Thu, 14 Jan 2010 22:38:09 -0500
lib: Introduce strnstr()
It differs strstr() in that it limits the length to be searched
in the first string.
Signed-off-by: Li Zefan <lizf@xxxxxxxxxxxxxx>
LKML-Reference: <4B4E8743.6030805@xxxxxxxxxxxxxx>
Acked-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
include/linux/string.h | 5 ++++-
lib/string.c | 27 ++++++++++++++++++++++++++-
2 files changed, 30 insertions(+), 2 deletions(-)
diff --git a/include/linux/string.h b/include/linux/string.h
index 651839a..a716ee2 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -72,7 +72,10 @@ static inline __must_check char *strstrip(char *str)
}
#ifndef __HAVE_ARCH_STRSTR
-extern char * strstr(const char *,const char *);
+extern char * strstr(const char *, const char *);
+#endif
+#ifndef __HAVE_ARCH_STRNSTR
+extern char * strnstr(const char *, const char *, size_t);
#endif
#ifndef __HAVE_ARCH_STRLEN
extern __kernel_size_t strlen(const char *);
diff --git a/lib/string.c b/lib/string.c
index 9f75b4e..a1cdcfc 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -667,7 +667,7 @@ EXPORT_SYMBOL(memscan);
*/
char *strstr(const char *s1, const char *s2)
{
- int l1, l2;
+ size_t l1, l2;
l2 = strlen(s2);
if (!l2)
@@ -684,6 +684,31 @@ char *strstr(const char *s1, const char *s2)
EXPORT_SYMBOL(strstr);
#endif
+#ifndef __HAVE_ARCH_STRNSTR
+/**
+ * strnstr - Find the first substring in a length-limited string
+ * @s1: The string to be searched
+ * @s2: The string to search for
+ * @len: the maximum number of characters to search
+ */
+char *strnstr(const char *s1, const char *s2, size_t len)
+{
+ size_t l1 = len, l2;
+
+ l2 = strlen(s2);
+ if (!l2)
+ return (char *)s1;
+ while (l1 >= l2) {
+ l1--;
+ if (!memcmp(s1, s2, l2))
+ return (char *)s1;
+ s1++;
+ }
+ return NULL;
+}
+EXPORT_SYMBOL(strnstr);
+#endif
+
#ifndef __HAVE_ARCH_MEMCHR
/**
* memchr - Find a character in an area of memory.
--
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