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1 /*
2  * Copyright (C) 2023 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #include <sys/inotify.h>
18 #include <unistd.h>
19 #include <string>
20 #include <vector>
21 
22 #include <android-base/logging.h>
23 
24 namespace cuttlefish {
25 
26 #define INOTIFY_MAX_EVENT_SIZE (sizeof(struct inotify_event) + NAME_MAX + 1)
GetCreatedFileListFromInotifyFd(int fd)27 std::vector<std::string> GetCreatedFileListFromInotifyFd(int fd) {
28   char event_readout[INOTIFY_MAX_EVENT_SIZE];
29   int bytes_parsed = 0;
30   std::vector<std::string> result;
31   // Each successful read can contain one or more of inotify_event events
32   // Note: read() on inotify returns 'whole' events, will never partially
33   // populate the buffer.
34   int event_read_out_length = read(fd, event_readout, INOTIFY_MAX_EVENT_SIZE);
35 
36   if (event_read_out_length == -1) {
37     LOG(ERROR) << __FUNCTION__
38                << ": Couldn't read out inotify event due to error: '"
39                << strerror(errno) << "' (" << errno << ")";
40     return std::vector<std::string>();
41   }
42 
43   while (bytes_parsed < event_read_out_length) {
44     struct inotify_event* event =
45         reinterpret_cast<inotify_event*>(event_readout + bytes_parsed);
46     bytes_parsed += sizeof(struct inotify_event) + event->len;
47 
48     // No file name was present
49     if (event->len == 0) {
50       LOG(ERROR) << __FUNCTION__ << ": inotify event didn't contain filename";
51       continue;
52     }
53     if (!(event->mask & IN_CREATE)) {
54       LOG(ERROR) << __FUNCTION__
55                  << ": inotify event didn't pertain to file creation";
56       continue;
57     }
58     result.push_back(std::string(event->name));
59   }
60 
61   return result;
62 }
63 
64 }  // namespace cuttlefish
65