Re: [PATCH] dpkg: acquire a read (shared) locks while building packages

[Jan Kiszka <jan.kiszka@siemens.com>]

On 08.03.19 10:57, Cedric Hombourger wrote:
> As debhelper scripts involved during the actual build process
> (dpkg-buildpackage) may access the dpkg database, we need to
> make sure it does not get modified in the background by other
> build tasks for other packages (such as install_build_deps).
> An example of a reader is dh_shlibdeps/dpkg-shlibdeps: it
> needs to find packages providing the shared libraries the
> package depends on to substitue shlibs variables found in its

substitute

> control file with package dependencies. Acquire the isar-apt
> lock as a shared lock to block writers.

Ah... Understood now.

> 
> Signed-off-by: Cedric Hombourger <Cedric_Hombourger@mentor.com>
> ---
>   meta/classes/dpkg.bbclass | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/meta/classes/dpkg.bbclass b/meta/classes/dpkg.bbclass
> index 24b9fe3..f4e3d7a 100644
> --- a/meta/classes/dpkg.bbclass
> +++ b/meta/classes/dpkg.bbclass
> @@ -19,5 +19,6 @@ do_install_builddeps[stamp-extra-info] = "${DISTRO}-${DISTRO_ARCH}"
>   # Build package from sources using build script
>   dpkg_runbuild() {
>       E="${@ bb.utils.export_proxies(d)}"
> +    flock -s "${REPO_ISAR_DIR}/isar.lock" \
>       sudo -E chroot --userspec=$( id -u ):$( id -g ) ${BUILDCHROOT_DIR} /isar/build.sh ${PP}/${PPS} ${DISTRO_ARCH}
>   }
> 

Couldn't we have the same issue with dpkg-base derived classes? The kernel? Or 
downstream classes? IOW, shouldn't this go to the caller of dpkg_runbuild?

Jan

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