lib: Adding the strstr() function

The strstr function finds the first occurrence of a substring
in another string, null terminated strings are not compared, this
function is added for compability for porting other libraries (like
mbedtls)

Jira: ZEP-327

Origin: http://www.leidinger.net/freebsd/dox/libkern/html/d3/d29/
strstr_8c_source.html

Change-Id: I52aac218ce0bd86373ec60f5afc49a92c85f6319
Signed-off-by: Sergio Rodriguez <sergio.sf.rodriguez@intel.com>

3 files changed, 63 insertions, 1 deletions

diff --git a/lib/libc/minimal/include/string.h b/lib/libc/minimal/include/string.h
index 2b4f860b2..8e98dd4c2 100644
--- a/lib/libc/minimal/include/string.h
+++ b/lib/libc/minimal/include/string.h
@@ -35,6 +35,7 @@ extern int    strcmp(const char *s1, const char *s2);
 extern int    strncmp(const char *s1, const char *s2, size_t n);
 extern char *strcat(char *_Restrict dest, const char *_Restrict src);
 extern char  *strncat(char *_Restrict d, const char *_Restrict s, size_t n);
+extern char *strstr(const char *s, const char *find);
 
 extern int    memcmp(const void *m1, const void *m2, size_t n);
 extern void  *memmove(void *d, const void *s, size_t n);
diff --git a/lib/libc/minimal/source/string/Makefile b/lib/libc/minimal/source/string/Makefile
index c64286d68..e9d047635 100644
--- a/lib/libc/minimal/source/string/Makefile
+++ b/lib/libc/minimal/source/string/Makefile
@@ -1,2 +1,2 @@
 obj-y := string.o
-obj-$(CONFIG_MINIMAL_LIBC_EXTENDED) += strncasecmp.o
+obj-$(CONFIG_MINIMAL_LIBC_EXTENDED) += strncasecmp.o strstr.o
diff --git a/lib/libc/minimal/source/string/strstr.c b/lib/libc/minimal/source/string/strstr.c
new file mode 100644
index 000000000..73348934a
--- /dev/null
+++ b/lib/libc/minimal/source/string/strstr.c
@@ -0,0 +1,61 @@
+/*-
+ * Copyright (c) 1990, 1993
+ *      The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Chris Torek.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgment:
+ *      This product includes software developed by the University of
+ *      California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <string.h>
+
+/*
+ * Find the first occurrence of find in s.
+ */
+char *
+strstr(const char *s, const char *find)
+{
+	char c, sc;
+	size_t len;
+
+	c = *find++;
+	if (c != 0) {
+		len = strlen(find);
+		do {
+			do {
+				sc = *s++;
+				if (sc == 0)
+				return NULL;
+			} while (sc != c);
+		} while (strncmp(s, find, len) != 0);
+	s--;
+	}
+	return (char *)s;
+}