Implement library function strnstr().
Implement strstr() using strnstr().
Sort the includes.
Signed-off-by: Heinrich Schuchardt <heinrich.schucha...@canonical.com>
---
include/linux/string.h | 3 +++
lib/string.c | 49 +++++++++++++++++++++++++++++-------------
2 files changed, 37 insertions(+), 15 deletions(-)
diff --git a/include/linux/string.h b/include/linux/string.h
index 27b2beb9ddb..8a377a8176a 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -72,6 +72,9 @@ extern char * strrchr(const char *,int);
#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 feae9519f2f..d5a486fb89d 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -16,11 +16,12 @@
*/
#include <config.h>
+#include <malloc.h>
+#include <stdint.h>
#include <linux/compiler.h>
+#include <linux/ctype.h>
#include <linux/types.h>
#include <linux/string.h>
-#include <linux/ctype.h>
-#include <malloc.h>
/**
* strncasecmp - Case insensitive, length-limited string comparison
@@ -678,30 +679,48 @@ char *memdup(const void *src, size_t len)
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.
--
2.47.1
