Yocto build container: start as builduser

Signed-off-by: Thomas Klaehn <thomas.klaehn@u-blox.com>

Dockerfile

@@ -1,6 +1,6 @@
 FROM debian:jessie
 
-MAINTAINER Thomas Klaehn <thomas.klaehn@u-blox.com>
+LABEL maintainer="thomas.klaehn@u-blox.com"
 
 RUN apt-get update && \
 	apt-get install -yq sudo build-essential git python python3 man bash diffstat \
@@ -19,11 +19,6 @@ RUN echo "en_US.UTF-8 UTF-8" > /etc/locale.gen && locale-gen
 
 ENV LANG en_US.utf8
 
-RUN mkdir -p /var/build
-
-WORKDIR /var/build
-
 ADD init.sh /usr/local/bin/init.sh
 
 ENTRYPOINT ["/usr/local/bin/init.sh"]
-

init.sh

@@ -1,31 +1,45 @@
 #!/bin/bash
 
-username=builduser
-usergroup=buildgroup
-builddir=/var/build
+now="$(date +%s >&1)"
+username=builduser_${now}
+usergroup=buildgroup_${now}
+builddir=$(pwd)
 homedir=/home/${username}
 sshdir=${homedir}/.ssh
 
-# figure out the uid/gid we need to use by integrating the path that has
-# been bind mounted in. this is then used for the builduser.
+# Figure out the uid/gid we need to use by integrating the path that has
+# been bind mounted in. This is then used for the builduser.
 BUILD_UID=$(stat --printf=%u ${builddir} 2> /dev/null)
 BUILD_GID=$(stat --printf=%g ${builddir} 2> /dev/null)
 
-# create a group
+# Add docker container group/user.
 groupadd --gid ${BUILD_GID} --non-unique ${usergroup}
-
-# add user
 useradd -s /bin/bash --home ${homedir} --non-unique --uid ${BUILD_UID} \
 	--gid ${BUILD_GID} --groups sudo ${username}
 
-# give users in the sudo group sudo access in the container
+# Give users in the sudo group sudo access in the container.
 echo '%sudo ALL=(ALL) NOPASSWD:ALL' >> /etc/sudoers
 
-# copy ssh key files
+# Copy ssh key files.
 mkdir -p ${homedir}
 mkdir -p ${sshdir}
 cp /var/ssh/* ${sshdir}/
 chown -R ${username}:${usergroup} ${homedir}
 
-exec "$@"
+# Determine parallel build capabilities.
+parallel_build="$(nproc >&1)"
 
+if [ ${parallel_build} -gt 20 ]
+then
+	BB_NUMBER_THREADS=20
+	PARALLEL_MAKE=20
+else
+	BB_NUMBER_THREADS=${parallel_build}
+	PARALLEL_MAKE=${parallel_build}
+fi
+
+export BB_NUMBER_THREADS
+export PARALLEL_MAKE
+
+# Execute CMD
+su ${username} -c "$@"