[PATCH v2 1/3] buildchroot: Align UID and GID of builder user with caller

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

This fixes EPERM on rebuild and also some clean builds: We have to align
the IDs of the builder user with the user in the host environment.
Otherwise, files and directories can become unaccessible during the
build.

Fixes: be291cd991bd ("buildchroot: build debian packages as "builder" not "root"")
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---

Changes in v2:
 - permit duplicate UID and GID inside buildchroot

 meta/recipes-devtools/buildchroot/buildchroot.inc       | 4 +++-
 meta/recipes-devtools/buildchroot/files/configscript.sh | 4 ++--
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/meta/recipes-devtools/buildchroot/buildchroot.inc b/meta/recipes-devtools/buildchroot/buildchroot.inc
index 7dd909e..2c44db9 100644
--- a/meta/recipes-devtools/buildchroot/buildchroot.inc
+++ b/meta/recipes-devtools/buildchroot/buildchroot.inc
@@ -36,7 +36,9 @@ do_build() {
 
     # Configure root filesystem
     sudo install -m 755 ${WORKDIR}/configscript.sh ${BUILDCHROOT_DIR}
-    sudo chroot ${BUILDCHROOT_DIR} /configscript.sh
+    USER_ID=$(id -u)
+    GROUP_ID=$(id -g)
+    sudo chroot ${BUILDCHROOT_DIR} /configscript.sh $USER_ID $GROUP_ID
 
     sudo mount --bind ${DL_DIR} ${BUILDCHROOT_DIR}/downloads
 }
diff --git a/meta/recipes-devtools/buildchroot/files/configscript.sh b/meta/recipes-devtools/buildchroot/files/configscript.sh
index 30660e7..25a21ef 100644
--- a/meta/recipes-devtools/buildchroot/files/configscript.sh
+++ b/meta/recipes-devtools/buildchroot/files/configscript.sh
@@ -10,6 +10,6 @@ locales locales/locales_to_be_generated multiselect en_US.UTF-8 UTF-8
 locales locales/default_environment_locale select en_US.UTF-8
 END
 
-addgroup --quiet --system builder
-useradd --system --gid builder --no-create-home --home /home/builder --no-user-group --comment "Isar buildchroot build user" builder
+groupadd --system builder -o --gid $2
+useradd --system -o --uid $1 --gid builder --no-create-home --home /home/builder --no-user-group --comment "Isar buildchroot build user" builder
 chown -R builder:builder /home/builder
-- 
2.16.4