1 /*
2  * Copyright 2012 Google, Inc
3  * Licensed under the Apache License, Version 2.0 (the "License");
4  * you may not use this file except in compliance with the License.
5  * You may obtain a copy of the License at
6  *
7  *     http://www.apache.org/licenses/LICENSE-2.0
8  *
9  * Unless required by applicable law or agreed to in writing, software
10  * distributed under the License is distributed on an "AS IS" BASIS,
11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12  * See the License for the specific language governing permissions and
13  * limitations under the License.
14  */
15 #include "sync.h"
16 #include <errno.h>
17 #include <poll.h>
18 #include <stdio.h>
19 
SyncWait(int num, int time)20 int SyncWait(int num, int time)
21 {
22     struct pollfd work;
23     int result;
24 
25     if (num < 0) {
26         errno = EINVAL;
27         return -1;
28     }
29 
30     work.fd = num;
31     work.events = POLLIN;
32 
33     do {
34         result = poll(&work, 1, time);
35         if (result > 0) {
36             if (work.revents & (POLLERR | POLLNVAL)) {
37                 errno = EINVAL;
38                 return -1;
39             }
40             return 0;
41         } else if (result == 0) {
42             errno = ETIME;
43             return -1;
44         }
45     } while (result == -1 && (errno == EINTR || errno == EAGAIN));
46 
47     return result;
48 }
49