packaging: consistently create build user in Dockerfiles

Previously, dockerlib.sh appended some commands to create a
"build" user in each Docker image. The resulting Docker images
could be inconsistent depending on the execution environment
and base image.

With this change, we explicitly create our custom user and
group as the first action in each Dockerfile. The user always
has user:group 1000:1000 and all built images are consistent.

We also create a home directory for the user under /build.
This directory is currently ignored.

As part of this, we stop setting the DBUILDUSER variable in
dockerlib.sh and instead set it in the respective scripts that
call it. This is in preparation for further refactoring of
dockerlib.sh.

Differential Revision: https://phab.mercurial-scm.org/D3758

contrib/packaging/docker/centos5

@@ -1,23 +1,27 b''
 FROM centos:centos5
+
+RUN groupadd -g 1000 build && \
+    useradd -u 1000 -g 1000 -s /bin/bash -d /build -m build
+
 RUN \
 	sed -i 's/^mirrorlist/#mirrorlist/' /etc/yum.repos.d/*.repo && \
 	sed -i 's/^#\(baseurl=\)http:\/\/mirror.centos.org\/centos/\1http:\/\/vault.centos.org/' /etc/yum.repos.d/*.repo && \
 	sed -i 's/\$releasever/5.11/' /etc/yum.repos.d/*.repo
 
 RUN yum install -y \
 	gcc \
 	gettext \
 	make \
 	python-devel \
 	python-docutils \
 	rpm-build \
 	tar
 
 # For creating repo meta data
 RUN yum install -y \
 	bzip2-devel \
 	createrepo \
 	ncurses-devel \
 	openssl-devel \
 	readline-devel \
 	zlib-devel

contrib/packaging/docker/centos6

@@ -1,20 +1,24 b''
 FROM centos:centos6
+
+RUN groupadd -g 1000 build && \
+    useradd -u 1000 -g 1000 -s /bin/bash -d /build -m build
+
 RUN yum install -y \
 	gcc \
 	gettext \
 	make \
 	python-devel \
 	python-docutils \
 	rpm-build \
 	tar
 
 # For creating repo meta data
 RUN yum install -y createrepo
 
 # For python
 RUN yum install -y \
 	bzip2-devel \
 	ncurses-devel \
 	openssl-devel \
 	readline-devel \
 	zlib-devel

contrib/packaging/docker/centos7

@@ -1,12 +1,16 b''
 FROM centos:centos7
+
+RUN groupadd -g 1000 build && \
+    useradd -u 1000 -g 1000 -s /bin/bash -d /build -m build
+
 RUN yum install -y \
 	gcc \
 	gettext \
 	make \
 	python-devel \
 	python-docutils \
 	rpm-build \
 	tar
 
 # For creating repo meta data
 RUN yum install -y createrepo

contrib/packaging/docker/debian.template

@@ -1,12 +1,16 b''
 FROM debian:__CODENAME__
+
+RUN groupadd -g 1000 build && \
+    useradd -u 1000 -g 1000 -s /bin/bash -d /build -m build
+
 RUN apt-get update && apt-get install -y \
   build-essential \
   debhelper \
   devscripts \
   dh-python \
   less \
   python \
   python-all-dev \
   python-docutils \
   unzip \
   zip

contrib/packaging/docker/fedora20

@@ -1,11 +1,15 b''
 FROM fedora:20
+
+RUN groupadd -g 1000 build && \
+    useradd -u 1000 -g 1000 -s /bin/bash -d /build -m build
+
 RUN yum install -y \
 	gcc \
 	gettext \
 	make \
 	python-devel \
 	python-docutils \
 	rpm-build
 
 # For creating repo meta data
 RUN yum install -y createrepo

contrib/packaging/docker/fedora21

@@ -1,11 +1,15 b''
 FROM fedora:21
+
+RUN groupadd -g 1000 build && \
+    useradd -u 1000 -g 1000 -s /bin/bash -d /build -m build
+
 RUN yum install -y \
 	gcc \
 	gettext \
 	make \
 	python-devel \
 	python-docutils \
 	rpm-build
 
 # For creating repo meta data
 RUN yum install -y createrepo

contrib/packaging/docker/ubuntu.template

@@ -1,12 +1,16 b''
 FROM ubuntu:__CODENAME__
+
+RUN groupadd -g 1000 build && \
+    useradd -u 1000 -g 1000 -s /bin/bash -d /build -m build
+
 RUN apt-get update && apt-get install -y \
   build-essential \
   debhelper \
   devscripts \
   dh-python \
   less \
   python \
   python-all-dev \
   python-docutils \
   unzip \
   zip

contrib/packaging/dockerdeb

@@ -1,35 +1,37 b''
 #!/bin/bash -eu
 
 . $(dirname $0)/dockerlib.sh
 . $(dirname $0)/packagelib.sh
 
 BUILDDIR=$(dirname $0)
 export ROOTDIR=$(cd $BUILDDIR/../.. > /dev/null; pwd)
 
 checkdocker
 
 DISTID="$1"
 CODENAME="$2"
 PLATFORM="$1-$2"
 shift; shift # extra params are passed to build process
 
 OUTPUTDIR=${OUTPUTDIR:=$ROOTDIR/packages/$PLATFORM}
 
 initcontainer $PLATFORM
 
 # debuild only appears to be able to save built debs etc to .., so we
 # have to share the .. of the current directory with the docker
 # container and hope it's writable. Whee.
 dn=$(basename $ROOTDIR)
 
+DBUILDUSER=build
+
 if [ $(uname) = "Darwin" ] ; then
     $DOCKER run -u $DBUILDUSER --rm -v $PWD/..:/mnt $CONTAINER \
             sh -c "cd /mnt/$dn && make clean && make local"
 fi
 $DOCKER run -u $DBUILDUSER --rm -v $ROOTDIR/..:/mnt $CONTAINER \
   sh -c "cd /mnt/$dn && DEB_BUILD_OPTIONS='${DEB_BUILD_OPTIONS:=}' contrib/packaging/builddeb --build --distid $DISTID --codename $CODENAME $@"
 contrib/packaging/builddeb --cleanup --distid $DISTID --codename $CODENAME
 if [ $(uname) = "Darwin" ] ; then
     $DOCKER run -u $DBUILDUSER --rm -v $PWD/..:/mnt $CONTAINER \
             sh -c "cd /mnt/$dn && make clean"
 fi

contrib/packaging/dockerlib.sh

@@ -1,42 +1,30 b''
 #!/bin/sh -eu
 
 # This function exists to set up the DOCKER variable and verify that
 # it's the binary we expect. It also verifies that the docker service
 # is running on the system and we can talk to it.
 function checkdocker() {
   if which docker.io >> /dev/null 2>&1 ; then
     DOCKER=docker.io
   elif which docker >> /dev/null 2>&1 ; then
     DOCKER=docker
   else
     echo "Error: docker must be installed"
     exit 1
   fi
 
   $DOCKER -h 2> /dev/null | grep -q Jansens && { echo "Error: $DOCKER is the Docking System Tray - install docker.io instead"; exit 1; }
   $DOCKER version | grep -Eq "^Client( version)?:" || { echo "Error: unexpected output from \"$DOCKER version\""; exit 1; }
   $DOCKER version | grep -Eq "^Server( version)?:" || { echo "Error: could not get docker server version - check it is running and your permissions"; exit 1; }
 }
 
 # Construct a container and leave its name in $CONTAINER for future use.
 function initcontainer() {
   [ "$1" ] || { echo "Error: platform name must be specified"; exit 1; }
 
   DFILE="$ROOTDIR/contrib/packaging/docker/$1"
   [ -f "$DFILE" ] || { echo "Error: docker file $DFILE not found"; exit 1; }
 
   CONTAINER="hg-dockerrpm-$1"
-  DBUILDUSER=build
-  (
-    cat $DFILE
-    if [ $(uname) = "Darwin" ] ; then
-        # The builder is using boot2docker on OS X, so we're going to
-        # *guess* the uid of the user inside the VM that is actually
-        # running docker. This is *very likely* to fail at some point.
-        echo RUN useradd $DBUILDUSER -u 1000
-    else
-        echo RUN groupadd $DBUILDUSER -g `id -g` -o
-        echo RUN useradd $DBUILDUSER -u `id -u` -g $DBUILDUSER -o
-    fi
-  ) | $DOCKER build --build-arg http_proxy --build-arg https_proxy --tag $CONTAINER -
+  cat $DFILE | $DOCKER build --build-arg http_proxy --build-arg https_proxy --tag $CONTAINER -
 }

contrib/packaging/dockerrpm

@@ -1,37 +1,39 b''
 #!/bin/bash -e
 
 . $(dirname $0)/dockerlib.sh
 
 BUILDDIR=$(dirname $0)
 export ROOTDIR=$(cd $BUILDDIR/../..; pwd)
 
 checkdocker
 
 PLATFORM="$1"
 shift # extra params are passed to buildrpm
 
 initcontainer $PLATFORM
 
 RPMBUILDDIR=$ROOTDIR/packages/$PLATFORM
 $ROOTDIR/contrib/packaging/buildrpm --rpmbuilddir $RPMBUILDDIR --prepare $*
 
 DSHARED=/mnt/shared
+DBUILDUSER=build
+
 $DOCKER run -e http_proxy -e https_proxy -u $DBUILDUSER --rm -v $RPMBUILDDIR:$DSHARED $CONTAINER \
     rpmbuild --define "_topdir $DSHARED" -ba $DSHARED/SPECS/mercurial.spec --clean
 
 $DOCKER run -e http_proxy -e https_proxy -u $DBUILDUSER --rm -v $RPMBUILDDIR:$DSHARED $CONTAINER \
     createrepo $DSHARED
 
 cat << EOF > $RPMBUILDDIR/mercurial.repo
 # Place this file in /etc/yum.repos.d/mercurial.repo
 [mercurial]
 name=Mercurial packages for $PLATFORM
 # baseurl=file://$RPMBUILDDIR/
 baseurl=http://hg.example.com/build/$PLATFORM/
 skip_if_unavailable=True
 gpgcheck=0
 enabled=1
 EOF
 
 echo
 echo "Build complete - results can be found in $RPMBUILDDIR"