scripts: make dockerenv.sh and docker_exec.sh podman-compatible

podman is a (almost) drop-in replacment to docker that runs rootless
and without a daemon. Since it runs rootless, it maps the host user to
the root user inside the container. This clashes with the tricks used
for docker to mount the volume with the same host user id and group
id. This script removes these docker tricks when using podman.

Author: benma

scripts/docker_exec.sh

@@ -18,9 +18,16 @@ DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null && pwd )"
 PROJECT_NAME="$(basename $(realpath "$DIR/.."))"
 CONTAINER_NAME=$PROJECT_NAME-dev
 
+if [ -n "$CONTAINER_RUNTIME" ]; then
+  RUNTIME="$CONTAINER_RUNTIME"
+elif command -v podman &>/dev/null; then
+  RUNTIME=podman
+else
+  RUNTIME=docker
+fi
 
 function docker_cleanup {
-    docker exec $IMAGE bash -c "if [ -f $PIDFILE ]; then kill -TERM -\$(cat $PIDFILE); rm $PIDFILE; fi"
+    $RUNTIME exec $IMAGE bash -c "if [ -f $PIDFILE ]; then kill -TERM -\$(cat $PIDFILE); rm $PIDFILE; fi"
 }
 
 # See https://github.com/moby/moby/issues/9098#issuecomment-189743947.
@@ -29,7 +36,14 @@ function docker_exec {
     PIDFILE=/tmp/docker-exec-$$
     shift
     trap 'kill $PID; docker_cleanup $IMAGE $PIDFILE' TERM INT
-    docker exec --user=dockeruser --workdir="$DIR/.." -i $IMAGE bash -c "echo \"\$\$\" > $PIDFILE; eval $*" &
+
+    USERFLAG=""
+    if [ "$RUNTIME" = "docker" ] ; then
+        # Only needed for docker - see the comments in dockerenv.sh.
+        USERFLAG="--user=dockeruser"
+    fi
+
+    $RUNTIME exec $USERFLAG --workdir="$DIR/.." -i $IMAGE bash -c "echo \"\$\$\" > $PIDFILE; eval $*" &
     PID=$!
     wait $PID
     RESULT=$?

scripts/dockerenv.sh

@@ -16,6 +16,14 @@
 
 DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null && pwd )"
 
+if [ -n "$CONTAINER_RUNTIME" ]; then
+  RUNTIME="$CONTAINER_RUNTIME"
+elif command -v podman &>/dev/null; then
+  RUNTIME=podman
+else
+  RUNTIME=docker
+fi
+
 if [ "$1" = "release" ] ; then
     MOUNT_DIR=/bb02
     CONTAINER_NAME_SUFFIX=rel
@@ -37,37 +45,46 @@ dockerdev () {
         exit 1
     fi
 
+    USERFLAG=""
+    if [ "$RUNTIME" = "docker" ] ; then
+        # Only needed for docker - see the comment below.
+        USERFLAG="--user=dockeruser"
+    fi
+
     # If already running, enter the container.
-    if docker ps --filter "name=^${CONTAINER_NAME}$" | grep -q "$CONTAINER_NAME"; then
-        docker exec --user=dockeruser --workdir="$MOUNT_DIR" -it "$CONTAINER_NAME" bash
+    if $RUNTIME ps --filter "name=^${CONTAINER_NAME}$" | grep -q "$CONTAINER_NAME"; then
+        $RUNTIME exec $USERFLAG --workdir="$MOUNT_DIR" -it "$CONTAINER_NAME" bash
         return
     fi
 
-    if docker ps --all --filter "name=^${CONTAINER_NAME}$" | grep -q "$CONTAINER_NAME"; then
-        docker rm "$CONTAINER_NAME"
+    if $RUNTIME ps --all --filter "name=^${CONTAINER_NAME}$" | grep -q "$CONTAINER_NAME"; then
+        $RUNTIME rm "$CONTAINER_NAME"
     fi
 
     # SYS_PTRACE is needed to run address sanitizer
-    docker run \
+    $RUNTIME run \
            --detach \
            --interactive --tty \
            --name="$CONTAINER_NAME" \
            -v "$repo_path":"$MOUNT_DIR" \
            --cap-add SYS_PTRACE \
            ${CONTAINER_IMAGE} bash
 
-    # Use same user/group id as on the host, so that files are not created as root in the mounted
-    # volume.
-    docker exec -it "$CONTAINER_NAME" groupadd -o -g "$(id -g)" dockergroup
-    docker exec -it "$CONTAINER_NAME" useradd -u "$(id -u)" -m -g dockergroup dockeruser
+    if [ "$RUNTIME" = "docker" ] ; then
+        # Use same user/group id as on the host, so that files are not created as root in the
+        # mounted volume. Only needed for Docker. On rootless podman, the host user maps to the
+        # container root user.
+        $RUNTIME exec -it "$CONTAINER_NAME" groupadd -o -g "$(id -g)" dockergroup
+        $RUNTIME exec -it "$CONTAINER_NAME" useradd -u "$(id -u)" -m -g dockergroup dockeruser
+    fi
 
     # Call a second time to enter the container.
     dockerdev
 }
 
 if test "$1" == "stop"; then
-    if docker ps -a | grep -q "$CONTAINER_NAME"; then
-        docker stop "$CONTAINER_NAME"
+    if $RUNTIME ps -a | grep -q "$CONTAINER_NAME"; then
+        $RUNTIME stop "$CONTAINER_NAME"
     fi
 else
     dockerdev