Re: [PATCH 2/2] initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP

[Benjamin Gray <bgray@linux.ibm.com>]

On Tue, 2023-06-06 at 13:14 +0900, Masahiro Yamada wrote:
> Hi Benjamin,
> 
> 
> I like this patch.
> 
> Will you send v2 with fixes I pointed out?
> (add double-quotes and remove the unneeded comment)
> 
> 
> On Sun, Apr 16, 2023 at 1:06 PM Masahiro Yamada
> <masahiroy@kernel.org> wrote:
> > 
> > On Mon, Mar 20, 2023 at 1:09 PM Benjamin Gray <bgray@linux.ibm.com>
> > wrote:
> > > 
> > > gen_initramfs.sh has an internal dependency on
> > > KBUILD_BUILD_TIMESTAMP
> > > for generating file mtimes that is not exposed to make, so
> > > changing
> > > KBUILD_BUILD_TIMESTAMP will not trigger a rebuild of the archive.
> > > 
> > > Declare the mtime date as a new parameter to gen_initramfs.sh to
> > > encode
> > > KBUILD_BUILD_TIMESTAMP in the shell command, thereby making make
> > > aware
> > > of the dependency.
> > > 
> > > It will rebuild if KBUILD_BUILD_TIMESTAMP changes or is newly
> > > set/unset.
> > > It will _not_ rebuild if KBUILD_BUILD_TIMESTAMP is unset before
> > > and
> > > after. This should be fine for anyone who doesn't care about
> > > setting
> > > specific build times in the first place.
> > > 
> > > Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
> > > 
> > > ---
> > > 
> > > Ran into this while debugging the issue in the first patch. Made
> > > for a
> > > very perplexing debug session before we worked out the state
> > > wasn't
> > > being rebuilt.
> > > ---
> > >  usr/Makefile         |  2 ++
> > >  usr/gen_initramfs.sh | 16 +++++++++-------
> > >  2 files changed, 11 insertions(+), 7 deletions(-)
> > > 
> > > diff --git a/usr/Makefile b/usr/Makefile
> > > index 59d9e8b07a01..2aa386cf48d6 100644
> > > --- a/usr/Makefile
> > > +++ b/usr/Makefile
> > > @@ -64,6 +64,7 @@ quiet_cmd_initfs = GEN     $@
> > >         $(CONFIG_SHELL) $< -o $@ -l $(obj)/.initramfs_data.cpio.d
> > > \
> > >         $(if $(CONFIG_INITRAMFS_ROOT_UID), -u
> > > $(CONFIG_INITRAMFS_ROOT_UID)) \
> > >         $(if $(CONFIG_INITRAMFS_ROOT_GID), -g
> > > $(CONFIG_INITRAMFS_ROOT_GID)) \
> > > +       $(if $(KBUILD_BUILD_TIMESTAMP), -d
> > > $(KBUILD_BUILD_TIMESTAMP)) \
> > >         $(ramfs-input)
> > 
> > 
> > 
> > If I apply this patch, I see a build error.
> > 
> > 
> > $ make -j16 KBUILD_BUILD_TIMESTAMP="$(date)"
> > [snip]
> >   GEN     usr/initramfs_data.cpio
> >   usr/gen_initramfs.sh: Cannot open 'Apr'
> > make[2]: *** [usr/Makefile:76: usr/initramfs_data.cpio] Error 1
> > make[1]: *** [scripts/Makefile.build:494: usr] Error 2
> > make[1]: *** Waiting for unfinished jobs....
> > 
> > 
> > 
> > 
> > Because KBUILD_BUILD_TIMESTAMP may contain spaces
> > depending on the format, init/Makefile and
> > kernel/gen_kheaders.sh surround the date with
> > double-quotes.
> > 
> > 
> > Double-quoting it in the same way fixes the issue.
> > 
> > $(if $(KBUILD_BUILD_TIMESTAMP), -d "$(KBUILD_BUILD_TIMESTAMP)") \
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > >  # We rebuild initramfs_data.cpio if:
> > > @@ -71,6 +72,7 @@ quiet_cmd_initfs = GEN     $@
> > >  # 2) There are changes in which files are included (added or
> > > deleted)
> > >  # 3) If gen_init_cpio are newer than initramfs_data.cpio
> > >  # 4) Arguments to gen_initramfs.sh changes
> > > +# 5) KBUILD_BUILD_TIMESTAMP is changed
> > 
> > 
> > This is unneeded because the change of KBUILD_BUILD_TIMESTAMP
> > is contained in
> > 
> >   4) Arguments to gen_initramfs.sh changes
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > >  $(obj)/initramfs_data.cpio: $(src)/gen_initramfs.sh
> > > $(obj)/gen_init_cpio $(deps_initramfs) FORCE
> > >         $(call if_changed,initfs)
> > > 
> > > diff --git a/usr/gen_initramfs.sh b/usr/gen_initramfs.sh
> > > index 63476bb70b41..14b5782f961a 100755
> > > --- a/usr/gen_initramfs.sh
> > > +++ b/usr/gen_initramfs.sh
> > > @@ -23,6 +23,7 @@ $0 [-o <file>] [-l <dep_list>] [-u <uid>] [-g
> > > <gid>] {-d | <cpio_source>} ...
> > >         -g <gid>       Group ID to map to group ID 0 (root).
> > >                        <gid> is only meaningful if <cpio_source>
> > > is a
> > >                        directory.  "squash" forces all files to
> > > gid 0.
> > > +       -d <date>      Use date for all file mtime values
> > >         <cpio_source>  File list or directory for cpio archive.
> > >                        If <cpio_source> is a .cpio file it will
> > > be used
> > >                        as direct input to initramfs.
> > > @@ -190,6 +191,7 @@ prog=$0
> > >  root_uid=0
> > >  root_gid=0
> > >  dep_list=
> > > +timestamp=
> > >  cpio_list=$(mktemp ${TMPDIR:-/tmp}/cpiolist.XXXXXX)
> > >  output="/dev/stdout"
> > > 
> > > @@ -218,6 +220,13 @@ while [ $# -gt 0 ]; do
> > >                         [ "$root_gid" = "-1" ] && root_gid=$(id -
> > > g || echo 0)
> > >                         shift
> > >                         ;;
> > > +               "-d")   # date for file mtimes
> > > +                       timestamp="$(date -d"$1" +%s || :)"
> > > +                       if test -n "$timestamp"; then
> > > +                               timestamp="-t $timestamp"
> > > +                       fi
> > > +                       shift
> > > +                       ;;
> > >                 "-h")
> > >                         usage
> > >                         exit 0
> > > @@ -237,11 +246,4 @@ done
> > > 
> > >  # If output_file is set we will generate cpio archive
> > >  # we are careful to delete tmp files
> > > -timestamp=
> > > -if test -n "$KBUILD_BUILD_TIMESTAMP"; then
> > > -       timestamp="$(date -d"$KBUILD_BUILD_TIMESTAMP" +%s || :)"
> > > -       if test -n "$timestamp"; then
> > > -               timestamp="-t $timestamp"
> > > -       fi
> > > -fi
> > >  usr/gen_init_cpio $timestamp $cpio_list > $output
> > > --
> > > 2.39.2
> > > 
> > 
> > 
> > --
> > Best Regards
> > Masahiro Yamada
> 
> 
> 
> --
> Best Regards
> Masahiro Yamada

Sorry, I forgot to follow up on this one. Sent the v2 now.