Add strndup

[Andreas Hauser]

Hoi,

this patch adds strndup(3) and makes strdup(3) use it.

-- 
Andy

http://ftp.fortunaty.net/DragonFly/inofficial/patches/strndup.patch

diff -r 818115c3be2b lib/libc/string/Makefile.inc
--- a/lib/libc/string/Makefile.inc	Sun Jun 11 22:54:18 2006 +0000
+++ b/lib/libc/string/Makefile.inc	Tue Jun 20 21:37:50 2006 +0200
@@ -34,6 +34,7 @@ MLINKS+=strcat.3 strncat.3
 MLINKS+=strcat.3 strncat.3
 MLINKS+=strcmp.3 strncmp.3
 MLINKS+=strcpy.3 strncpy.3
+MLINKS+=strdup.3 strndup.3
 MLINKS+=strerror.3 perror.3 strerror.3 sys_errlist.3 strerror.3 sys_nerr.3
 MLINKS+=strerror.3 strerror_r.3
 MLINKS+=strlcpy.3 strlcat.3
diff -r 818115c3be2b lib/libc/string/strdup.3
--- a/lib/libc/string/strdup.3	Sun Jun 11 22:54:18 2006 +0000
+++ b/lib/libc/string/strdup.3	Tue Jun 20 21:37:50 2006 +0200
@@ -38,6 +38,7 @@
 .Os
 .Sh NAME
 .Nm strdup
+.Nm strndup
 .Nd save a copy of a string
 .Sh LIBRARY
 .Lb libc
@@ -45,14 +46,22 @@
 .In string.h
 .Ft char *
 .Fn strdup "const char *str"
+.Ft char *
+.Fn strdup "const char *str" "size_t len"
 .Sh DESCRIPTION
 The
 .Fn strdup
-function
-allocates sufficient memory for a copy
+and
+.Fn strndup
+functions
+allocate sufficient memory for a copy
 of the string
 .Fa str ,
-does the copy, and returns a pointer to it.
+do the copy, and return a pointer to it. The
+.Fn strndup
+function copies
+.Fa len
+characters.
 The pointer may subsequently be used as an
 argument to the function
 .Xr free 3 .
diff -r 818115c3be2b lib/libc/string/strdup.c
--- a/lib/libc/string/strdup.c	Sun Jun 11 22:54:18 2006 +0000
+++ b/lib/libc/string/strdup.c	Tue Jun 20 21:37:50 2006 +0200
@@ -40,14 +40,20 @@
 #include <string.h>
 
 char *
+strndup(const char *str, size_t len)
+{
+	char *copy;
+
+	if ((copy = malloc(len + 1)) == NULL)
+		return (NULL);
+	memcpy(copy, str, len);
+    copy[len + 1] = '\0';
+	return (copy);
+}
+
+char *
 strdup(const char *str)
 {
-	size_t len;
-	char *copy;
+	return strndup(str, strlen(str));
+}
 
-	len = strlen(str) + 1;
-	if ((copy = malloc(len)) == NULL)
-		return (NULL);
-	memcpy(copy, str, len);
-	return (copy);
-}