ln: explain why we use xstrdup

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/coreutils/ln.c b/coreutils/ln.c
index ddad120..6da290c 100644 (file)
--- a/coreutils/ln.c
+++ b/coreutils/ln.c
@@ -40,8 +40,12 @@ int ln_main(int argc, char **argv)
        last = argv[argc - 1];
        argv += optind;
 
-       if (argc == optind + 1) {
+       if (!argv[1]) {
+               /* "ln PATH/TO/FILE" -> "ln PATH/TO/FILE FILE" */
                *--argv = last;
+               /* xstrdup is needed: "ln -s PATH/TO/FILE/" is equivalent to
+                * "ln -s PATH/TO/FILE/ FILE", not "ln -s PATH/TO/FILE FILE"
+                */
                last = bb_get_last_path_component_strip(xstrdup(last));
        }