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WIP: Add socat injection to rootfs build scripts

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Inject a statically-linked socat binary into rootfs images. envd's
port forwarder requires socat to bridge localhost-listening services
(e.g. Jupyter kernel) to the guest TAP interface.

Both scripts follow the same 3-step resolution: check rootfs, check
host, build from source (http://www.dest-unreach.org/socat/ v1.8.1.1).
Static linkage is verified before injection.

This is an intermediate state — needs further work for the full code
interpreter feature.
This commit is contained in:
Rafeed M. Bhuiyan
2026-03-26 02:11:54 +06:00
parent 8cdf91d895
commit 602ee470d9
2 changed files with 76 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

44
scripts/rootfs-from-container.sh
View File

@ -15,7 +15,8 @@
# Output:
# ${AGENT_FILES_ROOTDIR}/images/<image_name>/rootfs.ext4
#
# Requires: docker, mkfs.ext4, resize2fs, e2fsck, make (for building envd), curl (for tini download)
# Requires: docker, mkfs.ext4, resize2fs, e2fsck, make (for building envd), curl (for tini/socat download),
# gcc, make (for building socat from source)
# Sudo is used only for mount/umount/copy-into-image operations.
set -euo pipefail
@ -130,16 +131,51 @@ sudo mkdir -p "${MOUNT_DIR}/sbin"
sudo cp "${TINI_BIN}" "${MOUNT_DIR}/sbin/tini"
sudo chmod 755 "${MOUNT_DIR}/sbin/tini"
# Step 6: Verify.
echo "==> Installing socat..."
SOCAT_BIN=""
# 1. Already in the exported container image?
for p in "${MOUNT_DIR}/usr/bin/socat" "${MOUNT_DIR}/usr/local/bin/socat"; do
if [ -f "$p" ]; then SOCAT_BIN="$p"; break; fi
done
# 2. Available on the host?
if [ -z "${SOCAT_BIN}" ]; then
for p in /usr/bin/socat /usr/local/bin/socat; do
if [ -f "$p" ]; then SOCAT_BIN="$p"; break; fi
done
fi
# 3. Build from source.
if [ -z "${SOCAT_BIN}" ]; then
SOCAT_VERSION="1.8.1.1"
SOCAT_URL="http://www.dest-unreach.org/socat/download/socat-${SOCAT_VERSION}.tar.gz"
SOCAT_BUILD_DIR="/tmp/socat-build"
echo " Building socat ${SOCAT_VERSION} from source..."
rm -rf "${SOCAT_BUILD_DIR}"
mkdir -p "${SOCAT_BUILD_DIR}"
curl -fsSL "${SOCAT_URL}" | tar xz -C "${SOCAT_BUILD_DIR}" --strip-components=1
(cd "${SOCAT_BUILD_DIR}" && LDFLAGS="-static" ./configure --quiet && make -j"$(nproc)" -s)
SOCAT_BIN="${SOCAT_BUILD_DIR}/socat"
if [ ! -f "${SOCAT_BIN}" ]; then
echo "ERROR: socat build failed"
exit 1
fi
if ! file "${SOCAT_BIN}" | grep -q "statically linked"; then
echo "ERROR: socat is not statically linked!"
exit 1
fi
fi
sudo cp "${SOCAT_BIN}" "${MOUNT_DIR}/usr/local/bin/socat"
sudo chmod 755 "${MOUNT_DIR}/usr/local/bin/socat"
# Step 7: Verify.
echo ""
echo "==> Installed guest binaries:"
ls -la "${MOUNT_DIR}/usr/local/bin/envd" "${MOUNT_DIR}/usr/local/bin/wrenn-init" "${MOUNT_DIR}/sbin/tini"
ls -la "${MOUNT_DIR}/usr/local/bin/envd" "${MOUNT_DIR}/usr/local/bin/wrenn-init" "${MOUNT_DIR}/sbin/tini" "${MOUNT_DIR}/usr/local/bin/socat"
# Unmount before shrinking.
sudo umount "${MOUNT_DIR}"
rmdir "${MOUNT_DIR}" 2>/dev/null || true
# Step 7: Shrink the image to minimum size.
# Step 8: Shrink the image to minimum size.
echo ""
echo "==> Shrinking image..."
sudo e2fsck -fy "${OUTPUT_FILE}"

37
scripts/update-debug-rootfs.sh
View File

@ -96,10 +96,45 @@ sudo mkdir -p "${MOUNT_DIR}/sbin"
sudo cp "${TINI_BIN}" "${MOUNT_DIR}/sbin/tini"
sudo chmod 755 "${MOUNT_DIR}/sbin/tini"
echo "==> Installing socat..."
SOCAT_BIN=""
# 1. Already in the rootfs?
for p in "${MOUNT_DIR}/usr/bin/socat" "${MOUNT_DIR}/usr/local/bin/socat"; do
if [ -f "$p" ]; then SOCAT_BIN="$p"; break; fi
done
# 2. Available on the host?
if [ -z "${SOCAT_BIN}" ]; then
for p in /usr/bin/socat /usr/local/bin/socat; do
if [ -f "$p" ]; then SOCAT_BIN="$p"; break; fi
done
fi
# 3. Build from source.
if [ -z "${SOCAT_BIN}" ]; then
SOCAT_VERSION="1.8.1.1"
SOCAT_URL="http://www.dest-unreach.org/socat/download/socat-${SOCAT_VERSION}.tar.gz"
SOCAT_BUILD_DIR="/tmp/socat-build"
echo " Building socat ${SOCAT_VERSION} from source..."
rm -rf "${SOCAT_BUILD_DIR}"
mkdir -p "${SOCAT_BUILD_DIR}"
curl -fsSL "${SOCAT_URL}" | tar xz -C "${SOCAT_BUILD_DIR}" --strip-components=1
(cd "${SOCAT_BUILD_DIR}" && LDFLAGS="-static" ./configure --quiet && make -j"$(nproc)" -s)
SOCAT_BIN="${SOCAT_BUILD_DIR}/socat"
if [ ! -f "${SOCAT_BIN}" ]; then
echo "ERROR: socat build failed"
exit 1
fi
if ! file "${SOCAT_BIN}" | grep -q "statically linked"; then
echo "ERROR: socat is not statically linked!"
exit 1
fi
fi
sudo cp "${SOCAT_BIN}" "${MOUNT_DIR}/usr/local/bin/socat"
sudo chmod 755 "${MOUNT_DIR}/usr/local/bin/socat"
# Step 4: Verify.
echo ""
echo "==> Installed files:"
ls -la "${MOUNT_DIR}/usr/local/bin/envd" "${MOUNT_DIR}/usr/local/bin/wrenn-init" "${MOUNT_DIR}/sbin/tini"
ls -la "${MOUNT_DIR}/usr/local/bin/envd" "${MOUNT_DIR}/usr/local/bin/wrenn-init" "${MOUNT_DIR}/sbin/tini" "${MOUNT_DIR}/usr/local/bin/socat"
echo ""
echo "==> Done. Rootfs updated: ${ROOTFS}"