| Message ID | 20210424115553.396516-1-masahiroy@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | kbuild: add comment about why cmd_shipped uses 'cat' | expand |
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index a4fbaf8880b9..1677a7dcd18c 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -240,6 +240,9 @@ quiet_cmd_copy = COPY $@ # Shipped files # =========================================================================== +# 'cp' preserves permissions. If you use it to copy a file in read-only srctree, +# the copy would be read-only as well, leading to an error when executing the +# rule next time. Use 'cat' instead in order to generate a writable file. quiet_cmd_shipped = SHIPPED $@ cmd_shipped = cat $< > $@
cmd_shipped uses 'cat' instead of 'cp' for copying a file. The reason is explained in the commit [1], but it was in the pre-git era. $ touch a $ chmod -w a $ cp a b $ cp a b cp: cannot create regular file 'b': Permission denied Add comments so that you can see the reason without looking into the history. [1]: https://git.kernel.org/pub/scm/linux/kernel/git/history/history.git/commit/?id=a70dba8086160449cc94c5bdaff78419b6b8e3c8 Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> --- scripts/Makefile.lib | 3 +++ 1 file changed, 3 insertions(+)