xbps-src: added license to xbps-src-capchroot helper.

xbps-src/libexec/chroot.c

@@ -1,8 +1,35 @@
+/*-
+ * Copyright (c) 2010-2011 Juan Romero Pardines.
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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.
+ */
+
 /*
  * chroot() to target directory by using the CAP_CHROOT
  * capability set on the file.
  *
- * Juan RP - 2010/04/26 - Public Domain.
+ * As security measure it only allows to chroot when the target directory
+ * is owned by the same user executing the process and it has read/write
+ * permission on it.
  */
 #include <stdio.h>
 #include <stdlib.h>
@@ -15,10 +42,12 @@
 #include <sys/mount.h>
 #include <sys/capability.h>
 
+#define _PROGNAME	"xbps-src-capchroot"
+
 void
 usage(void)
 {
-	fprintf(stderr, "Usage: xbps-src-capchroot <newroot> <args>\n");
+	fprintf(stderr, "Usage: %s <newroot> <args>\n", _PROGNAME);
 	exit(EXIT_FAILURE);
 }