mcp-bash

#!/usr/bin/env bash # Portable lock-dir primitives for stdout serialization and state coordination. set -euo pipefail MCPBASH_LOCK_POLL_INTERVAL="${MCPBASH_LOCK_POLL_INTERVAL:-0.02}" MCPBASH_LOCK_REAP_GRACE_SECS="${MCPBASH_LOCK_REAP_GRACE_SECS:-1}" mcp_lock_init() { if [ -z "${MCPBASH_LOCK_ROOT}" ]; then printf '%s\n' 'MCPBASH_LOCK_ROOT not set; call mcp_runtime_init_paths first.' >&2 exit 1 fi mkdir -p "${MCPBASH_LOCK_ROOT}" } mcp_lock_path() { printf '%s/%s.lock' "${MCPBASH_LOCK_ROOT}" "$1" } mcp_lock_stat_mtime() { local path="$1" local mtime="0" if [ ! -e "${path}" ]; then printf '%s' "${mtime}" return 0 fi if command -v stat >/dev/null 2>&1; then if stat -c %Y "${path}" >/dev/null 2>&1; then mtime="$(stat -c %Y "${path}")" elif stat -f %m "${path}" >/dev/null 2>&1; then mtime="$(stat -f %m "${path}")" fi fi printf '%s' "${mtime}" } mcp_lock_acquire() { local name="$1" local path path="$(mcp_lock_path "${name}")" while :; do if mkdir "${path}" 2>/dev/null; then if printf '%s' "${BASHPID:-$$}" >"${path}/pid" 2>/dev/null; then break fi rm -rf "${path}" 2>/dev/null || true else mcp_lock_try_reap "${path}" sleep "${MCPBASH_LOCK_POLL_INTERVAL}" fi done } mcp_lock_acquire_timeout() { local name="$1" local timeout_secs="${2:-5}" local path path="$(mcp_lock_path "${name}")" local start start="$(date +%s)" while :; do if mkdir "${path}" 2>/dev/null; then if printf '%s' "${BASHPID:-$$}" >"${path}/pid" 2>/dev/null; then break fi rm -rf "${path}" 2>/dev/null || true else mcp_lock_try_reap "${path}" if [ "${timeout_secs}" -gt 0 ]; then local now now="$(date +%s)" if [ $((now - start)) -ge "${timeout_secs}" ]; then return 1 fi fi sleep "${MCPBASH_LOCK_POLL_INTERVAL}" fi done } mcp_lock_release() { local name="$1" local path local owner="" local current_pid="${BASHPID:-$$}" path="$(mcp_lock_path "${name}")" if [ -d "${path}" ]; then owner="$(cat "${path}/pid" 2>/dev/null || true)" if [ -z "${owner}" ] || [ "${owner}" = "${current_pid}" ] || ! kill -0 "${owner}" 2>/dev/null; then rm -rf "${path}" else printf '%s\n' "mcp-lock: refusing to release lock ${name} owned by pid ${owner}" >&2 fi fi } mcp_lock_try_reap() { local path="$1" local owner local current local now age mtime if [ ! -d "${path}" ]; then return fi if [ ! -f "${path}/pid" ]; then now="$(date +%s)" mtime="$(mcp_lock_stat_mtime "${path}")" age=$((now - mtime)) if [ "${age}" -lt "${MCPBASH_LOCK_REAP_GRACE_SECS}" ]; then # Grace window: allow the creator to finish writing the pid file. return fi rm -rf "${path}" return fi owner="$(cat "${path}/pid" 2>/dev/null || true)" if [ -z "${owner}" ]; then rm -rf "${path}" return fi if kill -0 "${owner}" 2>/dev/null; then return fi current="$(cat "${path}/pid" 2>/dev/null || true)" if [ "${current}" != "${owner}" ]; then return fi rm -rf "${path}" } mcp_lock_release_owned() { local name="$1" local owner_pid="$2" local path local recorded="" if [ -z "${name}" ] || [ -z "${owner_pid}" ]; then return 0 fi path="$(mcp_lock_path "${name}")" if [ ! -d "${path}" ]; then return 0 fi recorded="$(cat "${path}/pid" 2>/dev/null || true)" if [ -z "${recorded}" ]; then rm -rf "${path}" return 0 fi # Clear the lock if it belongs to the specified pid or the recorded owner is gone. if [ "${recorded}" = "${owner_pid}" ] || ! kill -0 "${recorded}" 2>/dev/null; then rm -rf "${path}" fi }