[PATCH] Fix invocation of b4.sh through a symlink

[PATCH] Fix invocation of b4.sh through a symlink

[Geert Uytterhoeven]

If b4 in your $PATH is a symlink pointing to b4.sh, $SCRIPT_TOP points
to the directory containing the symlink, and b4/command.py cannot be
found.

Fix this by following any symlinks, if present.

After this it works for being invoked through either an alias, symlink,
or plain path.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
Stack Overflow tells me "readlink -f" is not supported on OS X and some
BSDs. Do we care?
---
 b4.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/b4.sh b/b4.sh
index cafeee186115832d..e5459192d978e41b 100755
--- a/b4.sh
+++ b/b4.sh
@@ -3,6 +3,6 @@
 # Run b4 from a git checkout.
 #
 
-SCRIPT_TOP="${SCRIPT_TOP:-$(cd "${BASH_SOURCE%/*}" && pwd)}"
+SCRIPT_TOP="${SCRIPT_TOP:-$(dirname $(readlink -f $0))}"
 
 exec env PYTHONPATH="${SCRIPT_TOP}" python3 "${SCRIPT_TOP}/b4/command.py" "${@}"
-- 
2.17.1

Re: [PATCH] Fix invocation of b4.sh through a symlink

[Konstantin Ryabitsev]

On Tue, Mar 24, 2020 at 10:00:57AM +0100, Geert Uytterhoeven wrote:
> If b4 in your $PATH is a symlink pointing to b4.sh, $SCRIPT_TOP points
> to the directory containing the symlink, and b4/command.py cannot be
> found.
> 
> Fix this by following any symlinks, if present.
> 
> After this it works for being invoked through either an alias, symlink,
> or plain path.
> 
> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
> ---
> Stack Overflow tells me "readlink -f" is not supported on OS X and some
> BSDs. Do we care?

I used a similar patch that Greg sent because it used "realpath" 
instead. It doesn't exist at all on OSX/BSDs, but if they are doing any 
kernel development at all, they probably know how to install coreutils.  
I think that's an easier requirement than setting up a GNU-compatible 
version of readlink.

Best,
-K

Re: [PATCH] Fix invocation of b4.sh through a symlink

[Geert Uytterhoeven]

Hi Konstantin,

On Tue, Mar 24, 2020 at 3:33 PM Konstantin Ryabitsev
<konstantin@linuxfoundation.org> wrote:
> On Tue, Mar 24, 2020 at 10:00:57AM +0100, Geert Uytterhoeven wrote:
> > If b4 in your $PATH is a symlink pointing to b4.sh, $SCRIPT_TOP points
> > to the directory containing the symlink, and b4/command.py cannot be
> > found.
> >
> > Fix this by following any symlinks, if present.
> >
> > After this it works for being invoked through either an alias, symlink,
> > or plain path.
> >
> > Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
> > ---
> > Stack Overflow tells me "readlink -f" is not supported on OS X and some
> > BSDs. Do we care?
>
> I used a similar patch that Greg sent because it used "realpath"
> instead. It doesn't exist at all on OSX/BSDs, but if they are doing any
> kernel development at all, they probably know how to install coreutils.
> I think that's an easier requirement than setting up a GNU-compatible
> version of readlink.

Greg's version works fine for me, too.

Note that both readlink and realpath are part of coreutils ;-)

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds