[Buildroot] Issue with the HOST_DIR/usr -> HOST_DIR move

[Buildroot] Issue with the HOST_DIR/usr -> HOST_DIR move

[Thomas Petazzoni]

Hello Arnout,

I've started rebuilding the pre-built Buildroot external toolchains
after the HOST_DIR/usr -> HOST_DIR move. I've dropped my hack on the
toolchain wrapper to support the fact that I was moving the toolchain
out of the usr/ folder... because obviously this is no longer needed.
So basically, I'm building on top of master + a patch that builds
host-flex, host-gmp, host-mpc, etc. as static libraries instead of
shared ones.

Using this defconfig:

BR2_arm=y
BR2_HOST_DIR="/opt/br-arm-full-2017.05-1071-gef605f5"
BR2_JLEVEL=16
BR2_KERNEL_HEADERS_3_10=y
BR2_TOOLCHAIN_BUILDROOT_LOCALE=y
BR2_GCC_VERSION_4_9_X=y
BR2_TOOLCHAIN_BUILDROOT_CXX=y
BR2_INIT_NONE=y
BR2_SYSTEM_BIN_SH_NONE=y
# BR2_PACKAGE_BUSYBOX is not set
# BR2_TARGET_ROOTFS_TAR is not set

I'm seeing this build failure:

ESC[7m>>> uclibc 1.0.25 BuildingESC[27m
/usr/bin/make -j16 -C /opt/toolchain-build/build/uclibc-1.0.25 ARCH="arm" CROSS_COMPILE="/opt/br-arm-full-2017.05-1071-gef605f5/bin/arm-buildroot-linux-uclibcgnueabi-" UCLIBC_EXTRA_CFLAGS=" " HOSTCC="/usr/bin/gcc" headers
/opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory
/opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory
/opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory
/opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory
make[1]: Entering directory `/opt/toolchain-build/build/uclibc-1.0.25'
  MKDIR include/bits
  GEN include/bits/uClibc_config.h
/opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory
/opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory
/opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory
/opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory
  LN include/semaphore.h
  LN include/pthread.h
  LN include/bits/libc-lock.h
  LN include/bits/stdio-lock.h
  LN include/bits/pthreadtypes.h
  LN include/bits/semaphore.h
  GEN include/bits/sysnum.h
/opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory
/opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory

There are two problems here:

 * First, the problem that $(HOST_DIR)/usr didn't exist. The reason is
   that you rule that creates $(HOST_DIR)/usr is only triggered if the
   Buildroot Makefile creates $(HOST_DIR). But when you're building a
   SDK inside /opt/foo/, therefore setting BR2_HOST_DIR=/opt/foo/, it's
   pretty likely that /opt/foo/ might exist before Buildroot gets
   triggered. In such a situation, your $(HOST_DIR) rule in the main
   Makefile doesn't get triggered, and $(HOST_DIR)/usr is not created.

 * Even if the symlink doesn't exist, the build should still work.
   Indeed, the symlink was kept for backward compatibility reasons, but
   here I'm doing a full build from scratch, which I would expect to
   work even without the usr/ compatibility symlink.

Best regards,

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

[Buildroot] Issue with the HOST_DIR/usr -> HOST_DIR move

[Arnout Vandecappelle]

On 09-07-17 18:25, Thomas Petazzoni wrote:
> Hello Arnout,
> 
> I've started rebuilding the pre-built Buildroot external toolchains
> after the HOST_DIR/usr -> HOST_DIR move. I've dropped my hack on the
> toolchain wrapper to support the fact that I was moving the toolchain
> out of the usr/ folder... because obviously this is no longer needed.
> So basically, I'm building on top of master + a patch that builds
> host-flex, host-gmp, host-mpc, etc. as static libraries instead of
> shared ones.
> 
> Using this defconfig:
> 
> BR2_arm=y
> BR2_HOST_DIR="/opt/br-arm-full-2017.05-1071-gef605f5"
> BR2_JLEVEL=16
> BR2_KERNEL_HEADERS_3_10=y
> BR2_TOOLCHAIN_BUILDROOT_LOCALE=y
> BR2_GCC_VERSION_4_9_X=y
> BR2_TOOLCHAIN_BUILDROOT_CXX=y
> BR2_INIT_NONE=y
> BR2_SYSTEM_BIN_SH_NONE=y
> # BR2_PACKAGE_BUSYBOX is not set
> # BR2_TARGET_ROOTFS_TAR is not set
> 
> I'm seeing this build failure:
> 
> ESC[7m>>> uclibc 1.0.25 BuildingESC[27m
> /usr/bin/make -j16 -C /opt/toolchain-build/build/uclibc-1.0.25 ARCH="arm" CROSS_COMPILE="/opt/br-arm-full-2017.05-1071-gef605f5/bin/arm-buildroot-linux-uclibcgnueabi-" UCLIBC_EXTRA_CFLAGS=" " HOSTCC="/usr/bin/gcc" headers
> /opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory
> /opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory
> /opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory
> /opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory
> make[1]: Entering directory `/opt/toolchain-build/build/uclibc-1.0.25'
>   MKDIR include/bits
>   GEN include/bits/uClibc_config.h
> /opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory
> /opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory
> /opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory
> /opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory
>   LN include/semaphore.h
>   LN include/pthread.h
>   LN include/bits/libc-lock.h
>   LN include/bits/stdio-lock.h
>   LN include/bits/pthreadtypes.h
>   LN include/bits/semaphore.h
>   GEN include/bits/sysnum.h
> /opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory
> /opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory
> 
> There are two problems here:
> 
>  * First, the problem that $(HOST_DIR)/usr didn't exist. The reason is
>    that you rule that creates $(HOST_DIR)/usr is only triggered if the
>    Buildroot Makefile creates $(HOST_DIR). But when you're building a
>    SDK inside /opt/foo/, therefore setting BR2_HOST_DIR=/opt/foo/, it's
>    pretty likely that /opt/foo/ might exist before Buildroot gets
>    triggered. In such a situation, your $(HOST_DIR) rule in the main
>    Makefile doesn't get triggered, and $(HOST_DIR)/usr is not created.

 I never thought of that - I assumed that the HOST_DIR would always be created
by Buildroot. But indeed it does make sense to install a toolchain in a
pre-existing directory.

 There is one problem with that, though: in such a situation, it is also
possible that the usr/ directory already exists, so we can't create the
compatibility symlink. I guess we'll just have to live with that.

 I'll make an explicit rule for $(HOST_DIR)/usr to solve this.



>  * Even if the symlink doesn't exist, the build should still work.
>    Indeed, the symlink was kept for backward compatibility reasons, but
>    here I'm doing a full build from scratch, which I would expect to
>    work even without the usr/ compatibility symlink.

 D'oh, this is really, really weird, I'm sure I looked at that piece of code
when I made my initial version of the series, but apparently I didn't look at it
again last week. There are still *three* references to $(HOST_DIR)/usr in
toolchain-wrapper.c...


 Regards,
 Arnout

-- 
Arnout Vandecappelle                          arnout at mind be
Senior Embedded Software Architect            +32-16-286500
Essensium/Mind                                http://www.mind.be
G.Geenslaan 9, 3001 Leuven, Belgium           BE 872 984 063 RPR Leuven
LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle
GPG fingerprint:  7493 020B C7E3 8618 8DEC 222C 82EB F404 F9AC 0DDF

[Buildroot] Issue with the HOST_DIR/usr -> HOST_DIR move

[Yann E. MORIN]

Arnout, All,

On 2017-07-09 21:30 +0200, Arnout Vandecappelle spake thusly:
> On 09-07-17 18:25, Thomas Petazzoni wrote:
> > Hello Arnout,
> > 
> > I've started rebuilding the pre-built Buildroot external toolchains
> > after the HOST_DIR/usr -> HOST_DIR move. I've dropped my hack on the
> > toolchain wrapper to support the fact that I was moving the toolchain
> > out of the usr/ folder... because obviously this is no longer needed.
> > So basically, I'm building on top of master + a patch that builds
> > host-flex, host-gmp, host-mpc, etc. as static libraries instead of
> > shared ones.
> > 
> > Using this defconfig:
> > 
> > BR2_arm=y
> > BR2_HOST_DIR="/opt/br-arm-full-2017.05-1071-gef605f5"
> > BR2_JLEVEL=16
> > BR2_KERNEL_HEADERS_3_10=y
> > BR2_TOOLCHAIN_BUILDROOT_LOCALE=y
> > BR2_GCC_VERSION_4_9_X=y
> > BR2_TOOLCHAIN_BUILDROOT_CXX=y
> > BR2_INIT_NONE=y
> > BR2_SYSTEM_BIN_SH_NONE=y
> > # BR2_PACKAGE_BUSYBOX is not set
> > # BR2_TARGET_ROOTFS_TAR is not set
> > 
> > I'm seeing this build failure:
> > 
> > ESC[7m>>> uclibc 1.0.25 BuildingESC[27m
> > /usr/bin/make -j16 -C /opt/toolchain-build/build/uclibc-1.0.25 ARCH="arm" CROSS_COMPILE="/opt/br-arm-full-2017.05-1071-gef605f5/bin/arm-buildroot-linux-uclibcgnueabi-" UCLIBC_EXTRA_CFLAGS=" " HOSTCC="/usr/bin/gcc" headers
> > /opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory
> > /opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory
> > /opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory
> > /opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory
> > make[1]: Entering directory `/opt/toolchain-build/build/uclibc-1.0.25'
> >   MKDIR include/bits
> >   GEN include/bits/uClibc_config.h
> > /opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory
> > /opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory
> > /opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory
> > /opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory
> >   LN include/semaphore.h
> >   LN include/pthread.h
> >   LN include/bits/libc-lock.h
> >   LN include/bits/stdio-lock.h
> >   LN include/bits/pthreadtypes.h
> >   LN include/bits/semaphore.h
> >   GEN include/bits/sysnum.h
> > /opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory
> > /opt/br-arm-full-2017.05-1071-gef605f5/usr/bin/arm-buildroot-linux-uclibcgnueabi-gcc.br_real: No such file or directory
> > 
> > There are two problems here:
> > 
> >  * First, the problem that $(HOST_DIR)/usr didn't exist. The reason is
> >    that you rule that creates $(HOST_DIR)/usr is only triggered if the
> >    Buildroot Makefile creates $(HOST_DIR). But when you're building a
> >    SDK inside /opt/foo/, therefore setting BR2_HOST_DIR=/opt/foo/, it's
> >    pretty likely that /opt/foo/ might exist before Buildroot gets
> >    triggered. In such a situation, your $(HOST_DIR) rule in the main
> >    Makefile doesn't get triggered, and $(HOST_DIR)/usr is not created.
> 
>  I never thought of that - I assumed that the HOST_DIR would always be created
> by Buildroot. But indeed it does make sense to install a toolchain in a
> pre-existing directory.
> 
>  There is one problem with that, though: in such a situation, it is also
> possible that the usr/ directory already exists, so we can't create the
> compatibility symlink. I guess we'll just have to live with that.
> 
>  I'll make an explicit rule for $(HOST_DIR)/usr to solve this.

I can totally understand the need to install in an existing directory,
but I don;t think we should accept that there is a usr/ directory in
there.

As far as I understand, we keep the compatibility usr/ as a symlink for
two reasons:

  - that a host-package accidentally wants to install stuff in usr/ and
    we missed that (e.g. for out-of-tree host-packages), but still want
    the build to succeed,

  - that existing users' post-build/fakeroot/image scripts still work
    without modification.

However, we do not add $(HOST_DIR)/usr/{s,}bin in the PATH, so an
existing usr/ directory would have the potential to break when a package
unexpectedly installs stuff therein, especially out-of-tree packages.
And in this case, the build is broken.

So I would argue that we should only accept to use an existing directory
if it is empty.

Regards,
Yann E. MORIN.

> >  * Even if the symlink doesn't exist, the build should still work.
> >    Indeed, the symlink was kept for backward compatibility reasons, but
> >    here I'm doing a full build from scratch, which I would expect to
> >    work even without the usr/ compatibility symlink.
> 
>  D'oh, this is really, really weird, I'm sure I looked at that piece of code
> when I made my initial version of the series, but apparently I didn't look at it
> again last week. There are still *three* references to $(HOST_DIR)/usr in
> toolchain-wrapper.c...
> 
> 
>  Regards,
>  Arnout
> 
> -- 
> Arnout Vandecappelle                          arnout at mind be
> Senior Embedded Software Architect            +32-16-286500
> Essensium/Mind                                http://www.mind.be
> G.Geenslaan 9, 3001 Leuven, Belgium           BE 872 984 063 RPR Leuven
> LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle
> GPG fingerprint:  7493 020B C7E3 8618 8DEC 222C 82EB F404 F9AC 0DDF
> _______________________________________________
> buildroot mailing list
> buildroot at busybox.net
> http://lists.busybox.net/mailman/listinfo/buildroot

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[Buildroot] Issue with the HOST_DIR/usr -> HOST_DIR move

[Arnout Vandecappelle]

On 09-07-17 21:44, Yann E. MORIN wrote:
> Arnout, All,
> 
> On 2017-07-09 21:30 +0200, Arnout Vandecappelle spake thusly:

[snip]
>>  I'll make an explicit rule for $(HOST_DIR)/usr to solve this.

> I can totally understand the need to install in an existing directory,
> but I don;t think we should accept that there is a usr/ directory in
> there.
> 
> As far as I understand, we keep the compatibility usr/ as a symlink for
> two reasons:
> 
>   - that a host-package accidentally wants to install stuff in usr/ and
>     we missed that (e.g. for out-of-tree host-packages), but still want
>     the build to succeed,
> 
>   - that existing users' post-build/fakeroot/image scripts still work
>     without modification.
> 
> However, we do not add $(HOST_DIR)/usr/{s,}bin in the PATH, so an
> existing usr/ directory would have the potential to break when a package
> unexpectedly installs stuff therein, especially out-of-tree packages.
> And in this case, the build is broken.
> 
> So I would argue that we should only accept to use an existing directory
> if it is empty.

 I agree with your reasoning. However, it's a bit complicated to accomplish.
Since $(HOST_DIR)/usr exists already, we can't use the normal make dependency
mechanism to trigger the check. So we'd either need to FORCE it, or add another
PHONY rule just for this check.

 So I'm not sure that the added complexity is really warranted.

 I'll see if I can cook something up and add it as RFC to my series.

 Regards,
 Arnout

-- 
Arnout Vandecappelle                          arnout at mind be
Senior Embedded Software Architect            +32-16-286500
Essensium/Mind                                http://www.mind.be
G.Geenslaan 9, 3001 Leuven, Belgium           BE 872 984 063 RPR Leuven
LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle
GPG fingerprint:  7493 020B C7E3 8618 8DEC 222C 82EB F404 F9AC 0DDF