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List:       busybox
Subject:    Re: [PATCH] readlink: Support --, -n always
From:       Denys Vlasenko <vda.linux () googlemail ! com>
Date:       2023-04-16 16:02:17
Message-ID: CAK1hOcPM+BCz0S2K1eZBYqfxx5s_9s3D5iiL=6CE27qZ_0RYMA () mail ! gmail ! com
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Applied, thank you

On Mon, Apr 10, 2023 at 4:00 PM Eric Blake <eblake@redhat.com> wrote:
>
> Ping
>
> On Fri, Mar 24, 2023 at 09:58:14AM -0500, Eric Blake wrote:
> > POSIX will be standardizing readlink (just the -n option) and realpath
> > (just -E and -e options):
> > https://www.austingroupbugs.net/view.php?id=1457
> >
> > Change things for readlink so that the POSIX-mandated -n and -- work
> > even when disabling the non-standard (and partially non-working) -f
> > when FEATURE_READLINK_FOLLOW is clear.
> >
> > POSIX also wants readlink to be verbose by default (if the argument is
> > not a symlink, readlink must output a diagnostic); I did NOT address
> > that one, because I'm waiting to see what the GNU Coreutils folks do:
> > https://lists.gnu.org/archive/html/bug-coreutils/2023-03/msg00035.html
> >
> > Partial fix for https://bugs.busybox.net/show_bug.cgi?id=15466
> >
> > Signed-off-by: Eric Blake <eblake@redhat.com>
> > ---
> >  coreutils/readlink.c | 29 ++++++++++++-----------------
> >  1 file changed, 12 insertions(+), 17 deletions(-)
> >
> > diff --git a/coreutils/readlink.c b/coreutils/readlink.c
> > index b2e867883..0a9aa957e 100644
> > --- a/coreutils/readlink.c
> > +++ b/coreutils/readlink.c
> > @@ -25,12 +25,14 @@
> >  //kbuild:lib-$(CONFIG_READLINK) += readlink.o
> >
> >  //usage:#define readlink_trivial_usage
> > -//usage:     IF_FEATURE_READLINK_FOLLOW("[-fnv] ") "FILE"
> > +//usage:     IF_FEATURE_READLINK_FOLLOW("[-fnv] ")
> > +//usage:     IF_NOT_FEATURE_READLINK_FOLLOW("[-n] ")
> > +//usage:     "FILE"
> >  //usage:#define readlink_full_usage "\n\n"
> > -//usage:       "Display the value of a symlink"
> > -//usage:     IF_FEATURE_READLINK_FOLLOW( "\n"
> > -//usage:     "\n     -f      Canonicalize by following all symlinks"
> > +//usage:       "Display the value of a symlink" "\n"
> >  //usage:     "\n     -n      Don't add newline"
> > +//usage:     IF_FEATURE_READLINK_FOLLOW(
> > +//usage:     "\n     -f      Canonicalize by following all symlinks"
> >  //usage:     "\n     -v      Verbose"
> >  //usage:     )
> >
> > @@ -67,25 +69,18 @@ int readlink_main(int argc UNUSED_PARAM, char **argv)
> >  {
> >       char *buf;
> >       char *fname;
> > +     unsigned opt;
> >
> > -     IF_FEATURE_READLINK_FOLLOW(
> > -             unsigned opt;
> > -             /* We need exactly one non-option argument.  */
> > -             opt = getopt32(argv, "^" "fnvsq" "\0" "=1");
> > -             fname = argv[optind];
> > -     )
> > -     IF_NOT_FEATURE_READLINK_FOLLOW(
> > -             const unsigned opt = 0;
> > -             if (argc != 2) bb_show_usage();
> > -             fname = argv[1];
> > -     )
> > +     opt = getopt32(argv, "^" "n" IF_FEATURE_READLINK_FOLLOW("fvsq")
> > +                       "\0" "=1");
> > +     fname = argv[optind];
> >
> >       /* compat: coreutils readlink reports errors silently via exit code */
> >       if (!(opt & 4)) /* not -v */
> >               logmode = LOGMODE_NONE;
> >
> >       /* NOFORK: only one alloc is allowed; must free */
> > -     if (opt & 1) { /* -f */
> > +     if (opt & 2) { /* -f */
> >               buf = xmalloc_realpath_coreutils(fname);
> >       } else {
> >               buf = xmalloc_readlink_or_warn(fname);
> > @@ -93,7 +88,7 @@ int readlink_main(int argc UNUSED_PARAM, char **argv)
> >
> >       if (!buf)
> >               return EXIT_FAILURE;
> > -     printf((opt & 2) ? "%s" : "%s\n", buf);
> > +     printf((opt & 1) ? "%s" : "%s\n", buf);
> >       free(buf);
> >
> >       fflush_stdout_and_exit_SUCCESS();
> > --
> > 2.39.2
> >
> > _______________________________________________
> > busybox mailing list
> > busybox@busybox.net
> > http://lists.busybox.net/mailman/listinfo/busybox
> >
>
> --
> Eric Blake, Principal Software Engineer
> Red Hat, Inc.           +1-919-301-3266
> Virtualization:  qemu.org | libvirt.org
>
> _______________________________________________
> busybox mailing list
> busybox@busybox.net
> http://lists.busybox.net/mailman/listinfo/busybox
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