add strlcpy/strlcat, safe and sensible string copy/append

1 files changed, 71 insertions, 0 deletions

diff --git a/src/lib/libc/string/strlcat.c b/src/lib/libc/string/strlcat.c
new file mode 100644
index 0000000000..2e8c56926e
--- /dev/null
+++ b/src/lib/libc/string/strlcat.c
@@ -0,0 +1,71 @@
+/*      $OpenBSD: strlcat.c,v 1.1 1998/07/01 01:29:45 millert Exp $     */
+
+/*
+ * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
+ * All rights reserved.
+ *
+ * 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. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED ``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 AUTHOR 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.
+ */
+
+#if defined(LIBC_SCCS) && !defined(lint)
+static char *rcsid = "$OpenBSD: strlcat.c,v 1.1 1998/07/01 01:29:45 millert Exp $";
+#endif /* LIBC_SCCS and not lint */
+
+#include <sys/types.h>
+#include <string.h>
+
+/*
+ * Appends src to string dst of size siz (unlike strncat, siz is the
+ * full size of dst, not space left).  At most siz-1 characters
+ * will be copied.  Always NUL terminates (unless siz == 0).
+ * Returns strlen(src); if retval >= siz, truncation occurred.
+ */
+size_t strlcat(dst, src, siz)
+        char *dst;
+        const char *src;
+        size_t siz;
+{
+        register char *d = dst;
+        register const char *s = src;
+        register size_t n = siz;
+        size_t dlen;
+
+        /* Find the end of dst and adjust bytes left */
+        while (*d != '\0' && n != 0)
+                d++;
+        dlen = d - dst;
+        n -= dlen;
+
+        if (n == 0)
+                return(dlen + strlen(s));
+        while (*s != '\0') {
+                if (n != 1) {
+                        *d++ = *s;
+                        n--;
+                }
+                s++;
+        }
+        *d = '\0';
+
+        return(dlen + (s - src));       /* count does not include NUL */
+}