chmod: fix +X.

I broke this when I added the masking out of the S_IFMT bits for macOS,
because string_to_mode needs the full mode with those extra bits,
specifically so that it can recognize directories for +X to work.

I've duplicated chtest rather than change chtest to explicitly set the
modes to 000 before running the given chmod command because I didn't
want to touch *all* the tests and obscure the addition of just one.

2 files changed, 6 insertions, 1 deletions

diff --git a/tests/chmod.test b/tests/chmod.test
index cd4f8100..6c4de0c0 100755
--- a/tests/chmod.test
+++ b/tests/chmod.test
@@ -115,6 +115,11 @@ unset SKIP
 chtest +t  "drwxr-xr-t\n-rw-r--r-T\n"
 chtest a=r+w+x "drwxrwxrwx\n-rwxrwxrwx\n"
 
+# (chtest starts off with a directory that's +x...)
+testing "+X" \
+  "mkdir -m 000 Xd && touch Xf && chmod +X Xd Xf && ls -ld Xd Xf | cut -d' ' -f 1" \
+  "d--x--x--x\n-rw-r--r--\n" "" ""
+
 mkdir foo
 ln -s bar foo/baz
 # If you explicitly ask us, we'll try (and fail) to chmod a symlink.
diff --git a/toys/posix/chmod.c b/toys/posix/chmod.c
index 2cdda951..ef74c4fa 100644
--- a/toys/posix/chmod.c
+++ b/toys/posix/chmod.c
@@ -50,7 +50,7 @@ static int do_chmod(struct dirtree *try)
     // symlinks mentioned directly as arguments. We'll fail, of course,
     // but that's what you asked for in that case.
   } else {
-    mode = string_to_mode(TT.mode, try->st.st_mode & ~S_IFMT);
+    mode = string_to_mode(TT.mode, try->st.st_mode) & ~S_IFMT;
     if (FLAG(v)) {
       char *s = dirtree_path(try, 0);