[PATCH v2 2/3] arm: boot: Use double quotes for image name

[Simon Glass]

Hi Masahiro,

On Tue, 7 Nov 2023 at 07:13, Masahiro Yamada <masahiroy at kernel.org> wrote:
>
> Hi Simon,
>
>
> On Tue, Nov 7, 2023 at 3:11 PM Simon Glass <sjg at chromium.org> wrote:
> >
> > Hi Masahiro,
> >
> > On Tue, 7 Nov 2023 at 03:13, Masahiro Yamada <masahiroy at kernel.org> wrote:
> > >
> > > On Sat, Nov 4, 2023 at 9:42 PM Simon Glass <sjg at chromium.org> wrote:
> > > >
> > > > The use of single quotes in the image name causes them to appear in
> > > > the image description when the uImage is created. Use double quotes, to
> > > > avoid this.
> > > >
> > > > Signed-off-by: Simon Glass <sjg at chromium.org>
> > > > ---
> > > >
> > > > Changes in v2:
> > > > - Split double-quote change out into its own patch
> > > >
> > > >  scripts/Makefile.lib | 2 +-
> > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > >
> > > > diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
> > > > index 68d0134bdbf9..03e79e319293 100644
> > > > --- a/scripts/Makefile.lib
> > > > +++ b/scripts/Makefile.lib
> > > > @@ -487,7 +487,7 @@ UIMAGE_OPTS-y ?=
> > > >  UIMAGE_TYPE ?= kernel
> > > >  UIMAGE_LOADADDR ?= arch_must_set_this
> > > >  UIMAGE_ENTRYADDR ?= $(UIMAGE_LOADADDR)
> > > > -UIMAGE_NAME ?= 'Linux-$(KERNELRELEASE)'
> > > > +UIMAGE_NAME ?= "Linux-$(KERNELRELEASE)"
> > > >
> > > >  quiet_cmd_uimage = UIMAGE  $@
> > > >        cmd_uimage = $(BASH) $(MKIMAGE) -A $(UIMAGE_ARCH) -O linux \
> > > > --
> > > > 2.42.0.869.gea05f2083d-goog
> > > >
> > >
> > >
> > > NACK.
> > >
> > >
> > > This is because you are doing *WRONG* in 3/3.
> > >
> > > Look at your code closely.
> > >
> > > https://lore.kernel.org/linux-kbuild/20231104194207.3370542-4-sjg@chromium.org/T/#me2fb68151d6f4f330808406f9a711fffee149529
> > >
> > >
> > >
> > > In the mainline kernel, the quotation appears
> > > only in the definition of UIMAGE_NAME.
> > >
> > >
> > > masahiro at zoe:~/ref/linux(master)$ git grep UIMAGE_NAME
> > > scripts/Makefile.lib:UIMAGE_NAME ?= 'Linux-$(KERNELRELEASE)'
> > > scripts/Makefile.lib:                   -n $(UIMAGE_NAME) -d $< $@
> > >
> > >
> > > The single quotes are consumed by shell.
> > >
> > >
> > >
> > >
> > >
> > >
> > > This is mainline + your patch set.
> > >
> > > masahiro at zoe:~/ref/linux(simon-v2)$ git grep UIMAGE_NAME
> > > scripts/Makefile.lib:UIMAGE_NAME ?= "Linux-$(KERNELRELEASE)"
> > > scripts/Makefile.lib:                   -n "$(UIMAGE_NAME)" -d $< $@
> > > scripts/Makefile.lib:                   --name "$(UIMAGE_NAME)" \
> > >
> > >
> > > You quoted the definition of UIMAGE_NAME,
> > > and also variable references.
> > >
> > >
> > >
> > >
> > > See how it is expanded.
> > >
> > >
> > > --name "$(UIMAGE_NAME)"
> > >
> > >
> > >  ==>
> > >
> > >
> > > --name ""Linux-$(KERNELRELEASE)""
> > >
> > >
> > >  ==>
> > >
> > >
> > > --name Linux-$(KERNELRELEASE)
> > >
> > >
> > >
> > >
> > > You added double quotes in a row, just to cancel it.
> >
> > Yes, I understand that. But without the quotes in -n "$(UIMAGE_NAME)"
> > then the name cannot contain spaces. So we do need some sort of
> > quoting, right?
>
>
> Yes.
>
> If you move the quoting to the variable reference,
> it is acceptable because there is a good reason to do so.
>
>
>
> UIMAGE_NAME ?= Linux-$(KERNELRELEASE)
>
>
>             ...
>              -n '$(UIMAGE_NAME)' -d $< $@
>
>
> This is the correct change.

OK.

>
>
>
> >
> > It just seems strange to use single quotes in a Makefile variable. I
> > found it confusing.
>
>
> Right. Why don't you remove it, then?
>
>
> For clarification, there is no concept of quoting in GNU Make.
>
> The single quote character ' and the double quote character " are
> just normal characters for Make.
>
> GNU Make handles them just like alphabets and numbers.
>
> GNU Make just replaces $(UIMAGE_NAME)
> with 'Linux-$(KERNELRELEASE)' verbatim.
>
>
> It is the _shell_ that understands the quoting.
>
> Just in case here is the spec for
> "2.2.2 Single-Quotes" vs "2.2.3 Double-Quotes"
>
> https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html
>
>
> Shell supports both single-quoting and double-quoting
> for good reasons.
>
> There is no good or bad because both of them are meaningful.

Yes...I suppose I knew that Makefiles are completely literal, but
thanks for the pointers. I tend to use double quotes by default and
single quotes only when I have to...but it doesn't really matter so
long as it is consistent.

Anyway, moving the single quotes away from the var removes the
confusion I had at the start of all of this.

>
>
>
>
>
>
> >
> > I think you are saying you want to keep the single quotes in the var
> > declaration and drop the quotes from the cmd_fit rule. I am OK with
> > that, but I do think it is unusual not to quote something which might
> > have spaces. It may cause confusion for others, as it did for me?
> >
> > Anyway, I'll send a new version with the quoting reverted.
> >
>
>
> Please move the single quotes as I suggested above.
>
> The reason is because UIMAGE_NAME can be passed-in
> by a user and it can contain whitespaces.

OK, done in v4.

Regards,
Simon