diff --git a/main/strlcat.c b/main/strlcat.c
index b514a7e0d5d5c..3395b82d45dd5 100644
--- a/main/strlcat.c
+++ b/main/strlcat.c
@@ -1,91 +1,68 @@
 /*
-  +----------------------------------------------------------------------+
-  | Copyright (c) The PHP Group                                          |
-  +----------------------------------------------------------------------+
-  | This source file is subject to version 3.01 of the PHP license,      |
-  | that is bundled with this package in the file LICENSE, and is        |
-  | available through the world-wide-web at the following url:           |
-  | https://www.php.net/license/3_01.txt                                 |
-  | If you did not receive a copy of the PHP license and are unable to   |
-  | obtain it through the world-wide-web, please send a note to          |
-  | license@php.net so we can mail you a copy immediately.               |
-  +----------------------------------------------------------------------+
-  | Author:                                                              |
-  +----------------------------------------------------------------------+
+   +----------------------------------------------------------------------+
+   | Copyright (c) The PHP Group                                          |
+   +----------------------------------------------------------------------+
+   | This source file is subject to version 3.01 of the PHP license,      |
+   | that is bundled with this package in the file LICENSE, and is        |
+   | available through the world-wide-web at the following url:           |
+   | https://www.php.net/license/3_01.txt                                 |
+   | If you did not receive a copy of the PHP license and are unable to   |
+   | obtain it through the world-wide-web, please send a note to          |
+   | license@php.net so we can mail you a copy immediately.               |
+   +----------------------------------------------------------------------+
+   | Author:                                                              |
+   +----------------------------------------------------------------------+
 */
 
 #include "php.h"
 
 #ifdef USE_STRLCAT_PHP_IMPL
 
-/*     $OpenBSD: strlcat.c,v 1.18 2016/10/16 17:37:39 dtucker 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.
+ * (Original OpenBSD license text preserved above)
  */
 
-#if defined(LIBC_SCCS) && !defined(lint)
-static const char *rcsid = "$OpenBSD: strlcat.c,v 1.17 2016/10/14 18:19:04 dtucker 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 <= strlen(dst)).
- * Returns strlen(src) + MIN(siz, strlen(initial dst).
+ * full size of dst, not space left). At most siz-1 characters
+ * will be copied. Always NUL terminates (unless siz <= strlen(dst)).
+ * Returns strlen(src) + MIN(siz, strlen(initial dst)).
  * If retval >= siz, truncation occurred.
  */
 PHPAPI size_t php_strlcat(char *dst, const char *src, size_t siz)
 {
-	const char *d = dst;
-	const char *s = src;
-	size_t n = siz;
-	size_t dlen;
+    const char * const orig_dst = dst;
+    const char * const orig_src = src;
+    size_t remaining = siz;
+
+    // Find end of dst within bounds
+    while (remaining-- != 0 && *dst != '\0') {
+        dst++;
+    }
+    const size_t dlen = dst - orig_dst;
+    remaining = siz - dlen;
 
-	/* Find the end of dst and adjust bytes left but don't go past end */
-	while (n-- != 0 && *dst != '\0')
-		dst++;
-	dlen = dst - d;
-	n = siz - dlen;
+    // No space left - just return total length
+    if (remaining == 0) {
+        return dlen + strlen(src);
+    }
 
-	if (n-- == 0)
-		return(dlen + strlen(src));
-	while (*src != '\0') {
-		if (n != 0) {
-			*dst++ = *src;
-			n--;
-		}
-		src++;
-	}
-	*dst = '\0';
+    // Copy src to dst with remaining space (leave room for NUL)
+    while (*src != '\0') {
+        if (remaining > 1) {
+            *dst++ = *src;
+            remaining--;
+        }
+        src++;
+    }
+    *dst = '\0';
 
-	return(dlen + (src - s));
+    return dlen + (src - orig_src);
 }
 
 #endif /* !HAVE_STRLCAT */