Re: [PATCH] tty: vt: conmakehash: remove non-portable code printing comment header

[Max Krummenacher <max.oss.09@gmail.com>]

On Tue, Aug 13, 2024 at 12:44:40AM +0900, Masahiro Yamada wrote:
> On Mon, Aug 12, 2024 at 11:58 PM Max Krummenacher <max.oss.09@gmail.com> wrote:
> >
> > On Sat, Aug 10, 2024 at 01:07:20AM +0900, Masahiro Yamada wrote:
> > > Commit 6e20753da6bc ("tty: vt: conmakehash: cope with abs_srctree no
> > > longer in env") included <linux/limits.h>, which invoked another
> > > (wrong) patch that tried to address a build error on macOS.
> > >
> > > According to the specification [1], the correct header to use PATH_MAX
> > > is <limits.h>.
> > >
> > > The minimal fix would be to replace <linux/limits.h> with <limits.h>.
> > I can change that in a v2.
> 
> 
> You cannot.
> 
> Your buggy commit already landed in Linus' tree:
> 
> https://github.com/torvalds/linux/commit/6e20753da6bc651e02378a0cdb78f16c42098c88
> 
> 
> 
> 
> 
> > >
> > > However, the following commits seem questionable to me:
> > >
> > >  - 3bd85c6c97b2 ("tty: vt: conmakehash: Don't mention the full path of the input in output")
> > >  - 6e20753da6bc ("tty: vt: conmakehash: cope with abs_srctree no longer in env")
> > >
> > > These commits made too many efforts to cope with a comment header in
> > > drivers/tty/vt/consolemap_deftbl.c:
> > >
> > >   /*
> > >    * Do not edit this file; it was automatically generated by
> > >    *
> > >    * conmakehash drivers/tty/vt/cp437.uni > [this file]
> > >    *
> > >    */
> >
> > This is the output you get when keeping the build artifacts within the
> > linux source tree.
> > However if you keep the artifacts outside the source tree
> > (make O=/somepath ...) the output looks like this:
> >
> >     /*
> >      * Do not edit this file; it was automatically generated by
> >      *
> >      * conmakehash /path-to-kernel-source-tree/drivers/tty/vt/cp437.uni > [this file]
> >      *
> >      */
> >
> > i.e. it does keep a reference to where in your filesystem the kernel
> > source did reside when building which is against the goal of having a
> > reproducable build.
> 
> 
> 
> You do not need to educate me.
> 
> It is well described in commit 3bd85c6c97b2d232638594bf828de62083fe3389
> and I know how it works.

Sorry about that. I read your new commit as a comment to mine.
Thanks for fixing the bug I added.

Regards
Max

> 
> 
> 
> > >
> > > With this commit, the header part of the generate C file will be
> > > simplified as follows:
> > >
> > >   /*
> > >    * Automatically generated file; Do not edit.
> > >    */
> >
> > This is not what I observed, for me with this proposed commit the
> > comment becomes with or without the 'O=somepath':
> >
> >     /*
> >      * Do not edit this file; it was automatically generated by
> >      *
> >      * conmakehash cp437.uni > [this file]
> >      *
> >      */
> >
> > i.e. it strips the directory path of the chartable source file used.
> 
> 
> 
> See my patch closely.
> 
> I deleted the line "* conmakehash %s > [this file]\n\"
> 
> 
> 
> 
> 
> 
> 
> 
> 
> > Regards
> > Max
> >
> > >
> > > BTW, another series of excessive efforts for a comment header can be
> > > seen in the following:
> > >
> > >  - 5ef6dc08cfde ("lib/build_OID_registry: don't mention the full path of the script in output")
> > >  - 2fe29fe94563 ("lib/build_OID_registry: avoid non-destructive substitution for Perl < 5.13.2 compat")
> > >
> > > [1]: https://pubs.opengroup.org/onlinepubs/009695399/basedefs/limits.h.html
> > >
> > > Fixes: 6e20753da6bc ("tty: vt: conmakehash: cope with abs_srctree no longer in env")
> > > Reported-by: Daniel Gomez <da.gomez@samsung.com>
> > > Closes: https://lore.kernel.org/all/20240807-macos-build-support-v1-11-4cd1ded85694@samsung.com/
> > > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
> > > ---
> > >
> > >  drivers/tty/vt/conmakehash.c | 12 ++----------
> > >  1 file changed, 2 insertions(+), 10 deletions(-)
> > >
> > > diff --git a/drivers/tty/vt/conmakehash.c b/drivers/tty/vt/conmakehash.c
> > > index 82d9db68b2ce..a931fcde7ad9 100644
> > > --- a/drivers/tty/vt/conmakehash.c
> > > +++ b/drivers/tty/vt/conmakehash.c
> > > @@ -11,8 +11,6 @@
> > >   * Copyright (C) 1995-1997 H. Peter Anvin
> > >   */
> > >
> > > -#include <libgen.h>
> > > -#include <linux/limits.h>
> > >  #include <stdio.h>
> > >  #include <stdlib.h>
> > >  #include <sysexits.h>
> > > @@ -79,7 +77,6 @@ int main(int argc, char *argv[])
> > >  {
> > >    FILE *ctbl;
> > >    const char *tblname;
> > > -  char base_tblname[PATH_MAX];
> > >    char buffer[65536];
> > >    int fontlen;
> > >    int i, nuni, nent;
> > > @@ -245,20 +242,15 @@ int main(int argc, char *argv[])
> > >    for ( i = 0 ; i < fontlen ; i++ )
> > >      nuni += unicount[i];
> > >
> > > -  strncpy(base_tblname, tblname, PATH_MAX);
> > > -  base_tblname[PATH_MAX - 1] = 0;
> > >    printf("\
> > >  /*\n\
> > > - * Do not edit this file; it was automatically generated by\n\
> > > - *\n\
> > > - * conmakehash %s > [this file]\n\
> > > - *\n\
> > > + * Automatically generated file; Do not edit.\n\
> > >   */\n\
> > >  \n\
> > >  #include <linux/types.h>\n\
> > >  \n\
> > >  u8 dfont_unicount[%d] = \n\
> > > -{\n\t", basename(base_tblname), fontlen);
> > > +{\n\t", fontlen);
> > >
> > >    for ( i = 0 ; i < fontlen ; i++ )
> > >      {
> > > --
> > > 2.43.0
> > >
> 
> 
> 
> --
> Best Regards
> 
> Masahiro Yamada