From cf40e4b299ca4023f842eed1ecc5b254eb3eb688 Mon Sep 17 00:00:00 2001
From: Stefan Becker <stefanb2@users.noreply.github.com>
Date: Mon, 27 Mar 2023 16:30:34 +0300
Subject: [PATCH] Check that docker is not set up in rootless mode (#679)

Mounting binfmt_misc inside the container requires root rights. If
"docker info" indicates rootless mode then fall back to "sudo docker".

Allow the user to override the docker command with the DOCKER by setting
the environment variable.
---
 build-docker.sh | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/build-docker.sh b/build-docker.sh
index a7f18f1..b3995d5 100755
--- a/build-docker.sh
+++ b/build-docker.sh
@@ -4,10 +4,15 @@ DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
 
 BUILD_OPTS="$*"
 
-DOCKER="docker"
+# Allow user to override docker command
+DOCKER=${DOCKER:-docker}
 
-if ! ${DOCKER} ps >/dev/null 2>&1; then
-	DOCKER="sudo docker"
+# Ensure that default docker command is not set up in rootless mode
+if \
+  ! ${DOCKER} ps    >/dev/null 2>&1 || \
+    ${DOCKER} info 2>/dev/null | grep -q rootless \
+; then
+	DOCKER="sudo ${DOCKER}"
 fi
 if ! ${DOCKER} ps >/dev/null; then
 	echo "error connecting to docker:"