211 lines
6.9 KiB
Bash
211 lines
6.9 KiB
Bash
#!/bin/sh
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set -e
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CYAN="\033[1;36m"
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NC="\033[0m"
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log() { echo "$(date '+%Y-%m-%d %H:%M:%S') $*"; }
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fail() { echo "$(date '+%Y-%m-%d %H:%M:%S') [!] $*" >&2; exit 1; }
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print_banner() {
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version=$(cat VERSION 2>/dev/null || echo "unknown")
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title="Socat Proxy - Version ${version}"
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lines="Source: https://git.djeex.fr/Djeex/socat-proxy
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Mirror: https://github.com/Djeex/socat-proxy"
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width=${#title}
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old_ifs=$IFS
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IFS='
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'
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for l in $lines; do
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[ ${#l} -gt "$width" ] && width=${#l}
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done
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IFS=$old_ifs
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width=$((width + 2))
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border=""
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i=0
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while [ "$i" -lt "$width" ]; do
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border="${border}─"
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i=$((i + 1))
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done
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printf "${CYAN}╭%s╮${NC}\n" "$border"
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total_pad=$((width - ${#title}))
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left=$((total_pad / 2))
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right=$((total_pad - left))
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printf "${CYAN}│${NC}%*s%s%*s${CYAN}│${NC}\n" "$left" "" "$title" "$right" ""
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printf "${CYAN}├%s┤${NC}\n" "$border"
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IFS='
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'
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for l in $lines; do
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printf "${CYAN}│${NC} %-*s${CYAN}│${NC}\n" "$((width - 1))" "$l"
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done
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IFS=$old_ifs
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printf "${CYAN}╰%s╯${NC}\n" "$border"
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}
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print_banner
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DEBUG_LEVEL=${DEBUG_LEVEL:-1}
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UNIX_SOCKET_PATH=${UNIX_SOCKET_PATH%/}
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HOST_SOCKET_PATH=${HOST_SOCKET_PATH%/}
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FULL_HOST_SOCKET_PATH="$HOST_SOCKET_PATH/$UNIX_SOCKET_NAME"
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FULL_UNIX_SOCKET_PATH="$UNIX_SOCKET_PATH/$UNIX_SOCKET_NAME"
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# Validate required environment variables
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[ -n "$TARGET_HOST" ] || fail "TARGET_HOST environment variable is required"
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[ -n "$TARGET_PORT" ] || fail "TARGET_PORT environment variable is required"
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[ -n "$UNIX_SOCKET_NAME" ] || fail "UNIX_SOCKET_NAME environment variable is required"
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[ -n "$UNIX_SOCKET_PATH" ] || fail "UNIX_SOCKET_PATH environment variable is required"
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[ -n "$HOST_SOCKET_PATH" ] || fail "HOST_SOCKET_PATH environment variable is required"
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PUID=${PUID:-911}
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PGID=${PGID:-911}
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case "$PGID" in
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''|*[!0-9]*) fail "PGID '$PGID' is not a valid numeric group id." ;;
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esac
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case "$PUID" in
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''|*[!0-9]*) fail "PUID '$PUID' is not a valid numeric user id." ;;
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esac
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log "[i] Requested PUID=$PUID, PGID=$PGID"
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log "[~] Checking group for GID $PGID..."
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GROUP_NAME=$(getent group "$PGID" | cut -d: -f1 || true)
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if [ -z "$GROUP_NAME" ]; then
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log "[→] No existing group with GID $PGID, creating 'appgroup'."
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addgroup -g "$PGID" appgroup || fail "Failed to create group with GID $PGID (addgroup exited $?)."
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GROUP_NAME=appgroup
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else
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log "[i] Reusing existing group '$GROUP_NAME' (GID $PGID)."
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fi
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log "[✓] Group ready: $GROUP_NAME"
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log "[~] Checking user for UID $PUID..."
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USER_NAME=$(getent passwd "$PUID" | cut -d: -f1 || true)
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if [ -z "$USER_NAME" ]; then
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log "[→] No existing user with UID $PUID, creating 'appuser'."
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adduser -D -u "$PUID" -G "$GROUP_NAME" appuser || fail "Failed to create user with UID $PUID (adduser exited $?)."
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USER_NAME=appuser
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else
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log "[i] Reusing existing user '$USER_NAME' (UID $PUID)."
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fi
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log "[✓] User ready: $USER_NAME"
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log "[~] Starting socat proxy..."
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log "[i] TCP target: $TARGET_HOST:$TARGET_PORT"
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log "[i] HOST path: $HOST_SOCKET_PATH"
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log "[i] Full host socket path: $FULL_HOST_SOCKET_PATH"
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log "[i] Full socket path: $FULL_UNIX_SOCKET_PATH"
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# Check if socket file/folder exists and handle it
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if [ -e "$FULL_UNIX_SOCKET_PATH" ]; then
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log "[~] Socket file/folder $FULL_UNIX_SOCKET_PATH exists, removing it..."
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if rm -rf "$FULL_UNIX_SOCKET_PATH"; then
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log "[✓] Removed existing socket $FULL_UNIX_SOCKET_PATH"
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else
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fail "Failed to remove existing socket $FULL_UNIX_SOCKET_PATH"
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fi
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fi
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log "[~] Creating socket directory structure..."
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# Create directory if needed
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if mkdir -p "$UNIX_SOCKET_PATH"; then
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log "[✓] Created directory $UNIX_SOCKET_PATH"
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else
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fail "Failed to create directory $UNIX_SOCKET_PATH"
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fi
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# Grant the target user write access to the socket directory so the
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# su-exec'd socat process below can create the socket file in it.
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log "[~] Setting ownership of $UNIX_SOCKET_PATH to $USER_NAME:$GROUP_NAME..."
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chown "$USER_NAME:$GROUP_NAME" "$UNIX_SOCKET_PATH" || fail "chown on $UNIX_SOCKET_PATH failed — check that the host directory permissions allow it."
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log "[✓] Ownership set on $UNIX_SOCKET_PATH"
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log "[~] Preparing socket path..."
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# Create socket file by touching it, then remove it (this creates the path but leaves it clean for socat)
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touch "$FULL_UNIX_SOCKET_PATH"
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rm "$FULL_UNIX_SOCKET_PATH"
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log "[✓] Socket path prepared at $FULL_UNIX_SOCKET_PATH"
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# Debug: Check if socket file exists and its permissions
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if [ -S "$FULL_UNIX_SOCKET_PATH" ]; then
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log "[✓] Socket file exists and is a socket"
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ls -la "$FULL_UNIX_SOCKET_PATH"
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else
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log "[!] Socket file does not exist or is not a socket"
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ls -la "$UNIX_SOCKET_PATH"
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fi
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log "[~] Testing connection to target..."
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# Test if we can reach the target before starting socat
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if ! nc -z "$TARGET_HOST" "$TARGET_PORT" 2>/dev/null; then
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log "[!] Cannot connect to $TARGET_HOST:$TARGET_PORT - socat will retry automatically"
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else
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log "[✓] Connection to $TARGET_HOST:$TARGET_PORT is working"
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fi
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# Signal handler for graceful shutdown
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cleanup() {
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log "[!] Received SIGTERM, shutting down gracefully..."
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if [ -n "$SOCAT_PID" ]; then
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log "[~] Stopping socat process (PID: $SOCAT_PID)..."
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kill "$SOCAT_PID" 2>/dev/null || true
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wait "$SOCAT_PID" 2>/dev/null || true
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fi
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log "[~] Cleanup completed, exiting..."
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exit 0
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}
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# Set up signal trap
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trap cleanup SIGTERM SIGINT
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log "[~] Starting socat proxy..."
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# Start socat with configurable verbosity
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DEBUG_FLAGS=""
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if [ "$DEBUG_LEVEL" -eq 1 ]; then
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DEBUG_FLAGS="-d"
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elif [ "$DEBUG_LEVEL" -eq 2 ]; then
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DEBUG_FLAGS="-d -d"
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elif [ "$DEBUG_LEVEL" -eq 3 ]; then
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DEBUG_FLAGS="-d -d -d"
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fi
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log "[i] Using debug level: $DEBUG_LEVEL ($DEBUG_FLAGS)"
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# mode=666 keeps the socket connectable from another container's UID
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# regardless of PUID/PGID here — see project notes on the socket
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# permission trade-off (this proxy's own threat model is the host/network
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# boundary, not multi-tenant isolation between containers on the same host).
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log "[→] Dropping privileges to $USER_NAME:$GROUP_NAME and starting socat"
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if su-exec "$USER_NAME:$GROUP_NAME" socat $DEBUG_FLAGS UNIX-LISTEN:$FULL_UNIX_SOCKET_PATH,fork,unlink-early,mode=666 TCP:$TARGET_HOST:$TARGET_PORT & then
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SOCAT_PID=$!
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log "[✓] Socat started with PID: $SOCAT_PID"
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log "[i] Socat command: socat $DEBUG_FLAGS UNIX-LISTEN:$FULL_UNIX_SOCKET_PATH,fork,unlink-early,mode=666 TCP:$TARGET_HOST:$TARGET_PORT"
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log "[~] Container is ready and running..."
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# Debug: Check socket after socat starts
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sleep 2
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if [ -S "$FULL_UNIX_SOCKET_PATH" ]; then
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log "[✓] Socat socket is active"
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ls -la "$FULL_UNIX_SOCKET_PATH"
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else
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log "[!] Socat socket not found"
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fi
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else
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fail "Failed to start socat proxy"
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fi
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# Keep the script alive and wait for socat process
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while kill -0 "$SOCAT_PID" 2>/dev/null; do
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sleep 1
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done
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fail "Socat process has stopped"
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