1 files changed, 41 insertions, 20 deletions

diff --git a/lib/string.c b/lib/string.c
index 9f75b4ec50b8..f71bead1be3e 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -36,25 +36,21 @@ int strnicmp(const char *s1, const char *s2, size_t len)
         /* Yes, Virginia, it had better be unsigned */
         unsigned char c1, c2;
 
-        c1 = c2 = 0;
-        if (len) {
-                do {
-                        c1 = *s1;
-                        c2 = *s2;
-                        s1++;
-                        s2++;
-                        if (!c1)
-                                break;
-                        if (!c2)
-                                break;
-                        if (c1 == c2)
-                                continue;
-                        c1 = tolower(c1);
-                        c2 = tolower(c2);
-                        if (c1 != c2)
-                                break;
-                } while (--len);
-        }
+        if (!len)
+                return 0;
+
+        do {
+                c1 = *s1++;
+                c2 = *s2++;
+                if (!c1 || !c2)
+                        break;
+                if (c1 == c2)
+                        continue;
+                c1 = tolower(c1);
+                c2 = tolower(c2);
+                if (c1 != c2)
+                        break;
+        } while (--len);
         return (int)c1 - (int)c2;
 }
 EXPORT_SYMBOL(strnicmp);
@@ -667,7 +663,7 @@ 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 +680,31 @@ 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 l2;
+
+        l2 = strlen(s2);
+        if (!l2)
+                return (char *)s1;
+        while (len >= l2) {
+                len--;
+                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.