lib: implement strnstr()
Implement library function strnstr().
Implement strstr() using strnstr().
Sort the includes.
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
[jf: replace <stdint.h> by <limits.h>, folded from next patch]
Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>
diff --git a/include/linux/string.h b/include/linux/string.h
index 27b2beb..d943fcc 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -72,6 +72,9 @@
#ifndef __HAVE_ARCH_STRSTR
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 *);
#endif
diff --git a/lib/string.c b/lib/string.c
index 0e0900d..d56f88d 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -15,13 +15,14 @@
* reentrant and should be faster). Use only strsep() in new code, please.
*/
+#include <asm/sections.h>
#include <config.h>
+#include <limits.h>
#include <linux/compiler.h>
-#include <linux/types.h>
-#include <linux/string.h>
#include <linux/ctype.h>
+#include <linux/string.h>
+#include <linux/types.h>
#include <malloc.h>
-#include <asm/sections.h>
/**
* strncasecmp - Case insensitive, length-limited string comparison
@@ -679,30 +680,48 @@
return p;
}
-#ifndef __HAVE_ARCH_STRSTR
+#ifndef __HAVE_ARCH_STRNSTR
/**
- * strstr - Find the first substring in a %NUL terminated string
- * @s1: The string to be searched
- * @s2: The string to search for
+ * strnstr() - find the first substring occurrence in a NUL terminated string
+ *
+ * @s1: string to be searched
+ * @s2: string to search for
+ * @len: maximum number of characters in s2 to consider
+ *
+ * Return: pointer to the first occurrence or NULL
*/
-char * strstr(const char * s1,const char * s2)
+char *strnstr(const char *s1, const char *s2, size_t len)
{
- int l1, l2;
+ size_t l1, l2;
+ l1 = strnlen(s1, len);
l2 = strlen(s2);
- if (!l2)
- return (char *) s1;
- l1 = strlen(s1);
- while (l1 >= l2) {
- l1--;
- if (!memcmp(s1,s2,l2))
+
+ for (; l1 >= l2; --l1, ++s1) {
+ if (!memcmp(s1, s2, l2))
return (char *) s1;
- s1++;
}
+
return NULL;
}
#endif
+#ifndef __HAVE_ARCH_STRSTR
+/**
+ * strstr() - find the first substring occurrence in a NUL terminated string
+ *
+ * @s1: string to be searched
+ * @s2: string to search for
+ * @len: maximum number of characters in s2 to consider
+ *
+ * Return: pointer to the first occurrence or NULL
+ */
+char *strstr(const char *s1, const char *s2)
+{
+ return strnstr(s1, s2, SIZE_MAX);
+}
+#endif
+
#ifndef __HAVE_ARCH_MEMCHR
/**
* memchr - Find a character in an area of memory.