| -- |
| -- Licensed to the Apache Software Foundation (ASF) under one or more |
| -- contributor license agreements. See the NOTICE file distributed with |
| -- this work for additional information regarding copyright ownership. |
| -- The ASF licenses this file to You under the Apache License, Version 2.0 |
| -- (the "License"); you may not use this file except in compliance with |
| -- the License. You may obtain a copy of the License at |
| -- |
| -- http://www.apache.org/licenses/LICENSE-2.0 |
| -- |
| -- Unless required by applicable law or agreed to in writing, software |
| -- distributed under the License is distributed on an "AS IS" BASIS, |
| -- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| -- See the License for the specific language governing permissions and |
| -- limitations under the License. |
| -- |
| local ffi = require("ffi") |
| local ffi_str = ffi.string |
| local ffi_errno = ffi.errno |
| local C = ffi.C |
| local tostring = tostring |
| local type = type |
| |
| |
| local _M = {} |
| local WNOHANG = 1 |
| |
| |
| ffi.cdef[[ |
| typedef int32_t pid_t; |
| typedef unsigned int useconds_t; |
| |
| int setenv(const char *name, const char *value, int overwrite); |
| char *strerror(int errnum); |
| |
| int usleep(useconds_t usec); |
| pid_t waitpid(pid_t pid, int *wstatus, int options); |
| ]] |
| |
| |
| local function err() |
| return ffi_str(C.strerror(ffi_errno())) |
| end |
| |
| |
| -- setenv sets the value of the environment variable |
| function _M.setenv(name, value) |
| local tv = type(value) |
| if type(name) ~= "string" or (tv ~= "string" and tv ~= "number") then |
| return false, "invalid argument" |
| end |
| |
| value = tostring(value) |
| local ok = C.setenv(name, value, 1) == 0 |
| if not ok then |
| return false, err() |
| end |
| return true |
| end |
| |
| |
| local function waitpid_nohang(pid) |
| local res = C.waitpid(pid, nil, WNOHANG) |
| if res == -1 then |
| return nil, err() |
| end |
| return res > 0 |
| end |
| |
| |
| function _M.waitpid(pid, timeout) |
| local count = 0 |
| local step = 1000 * 10 |
| local total = timeout * 1000 * 1000 |
| while step * count < total do |
| count = count + 1 |
| C.usleep(step) |
| local ok, err = waitpid_nohang(pid) |
| if err then |
| return nil, err |
| end |
| if ok then |
| return true |
| end |
| end |
| end |
| |
| |
| return _M |