xref: /glogg/src/kqueuewatchtowerdriver.cpp (revision c1f737e476dd5f2427c03f48844bf9ed87cac11b)
1 /*
2  * Copyright (C) 2018 Nicolas Bonnefon and other contributors
3  *
4  * This file is part of glogg.
5  *
6  * glogg is free software: you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation, either version 3 of the License, or
9  * (at your option) any later version.
10  *
11  * glogg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with glogg.  If not, see <http://www.gnu.org/licenses/>.
18  */
19 
20 #include "kqueuewatchtowerdriver.h"
21 
22 #include <sys/types.h>
23 #include <sys/event.h>
24 #include <sys/time.h>
25 #include <fcntl.h>
26 #include <unistd.h>
27 
28 #include "log.h"
29 
30 #include "watchtowerlist.h"
31 
32 KQueueWatchTowerDriver::KQueueWatchTowerDriver() : kqueue_fd_( kqueue() )
33 {
34     int pipefd[2];
35 
36     pipe( pipefd );
37     fcntl( pipefd[0], F_SETFD, O_NONBLOCK );
38     fcntl( pipefd[1], F_SETFD, O_NONBLOCK );
39 
40     breaking_pipe_read_fd_  = pipefd[0];
41     breaking_pipe_write_fd_ = pipefd[1];
42 
43     struct kevent changelist;
44     const struct timespec no_timeout = { 0, 0 };
45 
46     EV_SET( &changelist,
47             breaking_pipe_read_fd_, // ident
48             EVFILT_READ, // filter
49             EV_ADD, // flags
50             0, // fflags
51             NULL, // data
52             (void*) 0 // opaque data
53           );
54 
55     // Add a watch for the breaking pipe
56     if ( kevent( kqueue_fd_, &changelist, 1, NULL, 0, &no_timeout ) != -1 )
57         LOG(logDEBUG) << "KQueueWatchTowerDriver::KQueueWatchTowerDriver breaking pipe monitored";
58     else
59         LOG(logERROR) << "KQueueWatchTowerDriver::KQueueWatchTowerDriver cannot add breaking pipe";
60 }
61 
62 KQueueWatchTowerDriver::~KQueueWatchTowerDriver()
63 {
64     close( breaking_pipe_read_fd_ );
65     close( breaking_pipe_write_fd_ );
66 
67     close( kqueue_fd_ );
68 }
69 
70 KQueueWatchTowerDriver::FileId KQueueWatchTowerDriver::addFile(
71         const std::string& file_name )
72 {
73     struct kevent changelist;
74     const struct timespec no_timeout = { 0, 0 };
75     int fd = open( file_name.c_str(), O_EVTONLY );
76 
77     if ( fd != -1 ) {
78         LOG(logDEBUG) << "KQueueWatchTowerDriver::addFile new fd " << fd << " for file " << file_name;
79         EV_SET( &changelist,
80                 fd, // ident
81                 EVFILT_VNODE, // filter
82                 EV_ADD | EV_ENABLE | EV_CLEAR, // flags
83                 NOTE_DELETE | NOTE_WRITE | NOTE_RENAME | NOTE_REVOKE, // fflags
84                 NULL, // data
85                 (void*) 0 // opaque data
86               );
87 
88         // Add a watch for the inode
89         if ( kevent( kqueue_fd_, &changelist, 1, NULL, 0, &no_timeout ) != -1 )
90             LOG(logDEBUG) << "KQueueWatchTowerDriver::addFile new kevent added for fd " << fd;
91         else
92             LOG(logERROR) << "KQueueWatchTowerDriver::addFile cannot add file";
93     }
94     else {
95         LOG(logERROR) << "KQueueWatchTowerDriver::addFile cannot open " << file_name;
96     }
97 
98     return { fd };
99 }
100 
101 KQueueWatchTowerDriver::SymlinkId KQueueWatchTowerDriver::addSymlink(
102         const std::string& file_name )
103 {
104     /*
105     int symlink_wd = inotify_add_watch( inotify_fd_, file_name.c_str(),
106             IN_DONT_FOLLOW | IN_DELETE_SELF | IN_MODIFY | IN_MOVE_SELF );
107     LOG(logDEBUG) << "INotifyWatchTower::addFile new inotify symlink_wd " << symlink_wd;
108     // (not sure a symlink can be modified but you never know)
109 
110     return { symlink_wd };
111     */
112     return { 0 };
113 }
114 
115 KQueueWatchTowerDriver::DirId KQueueWatchTowerDriver::addDir(
116         const std::string& file_name )
117 {
118     /*
119     int dir_wd = inotify_add_watch( inotify_fd_, file_name.c_str(),
120             IN_CREATE | IN_MOVE | IN_ONLYDIR );
121     LOG(logDEBUG) << "INotifyWatchTower::addFile dir " << file_name
122         << " watched wd " << dir_wd;
123 
124     return { dir_wd };
125         */
126     struct kevent changelist;
127     const struct timespec no_timeout = { 0, 0 };
128     int fd = open( file_name.c_str(), O_EVTONLY );
129 
130     if ( fd != -1 ) {
131         LOG(logDEBUG) << "KQueueWatchTowerDriver::addDir new fd " << fd << " for dir " << file_name;
132         EV_SET( &changelist,
133                 fd, // ident
134                 EVFILT_VNODE, // filter
135                 EV_ADD | EV_ENABLE | EV_CLEAR, // flags
136                 NOTE_WRITE, // fflags
137                 NULL, // data
138                 (void*) 0 // opaque data
139               );
140 
141         // Add a watch for the inode
142         if ( kevent( kqueue_fd_, &changelist, 1, NULL, 0, &no_timeout ) != -1 )
143             LOG(logDEBUG) << "KQueueWatchTowerDriver::addDir new kevent added for fd " << fd;
144         else
145             LOG(logERROR) << "KQueueWatchTowerDriver::addDir cannot add file";
146     }
147     else {
148         LOG(logERROR) << "KQueueWatchTowerDriver::addDir cannot open " << file_name;
149     }
150 
151     return { fd };
152 }
153 
154 void KQueueWatchTowerDriver::removeFile(
155         const KQueueWatchTowerDriver::FileId& file_id )
156 {
157     LOG(logDEBUG) << "KQueueWatchTowerDriver::removeFile removing fd " << file_id.fd_;
158     close( file_id.fd_ );
159 }
160 
161 void KQueueWatchTowerDriver::removeSymlink( const SymlinkId& symlink_id )
162 {
163     /*
164     if ( symlink_id.wd_ >= 0 )
165         inotify_rm_watch( inotify_fd_, symlink_id.wd_ );
166         */
167 }
168 
169 void KQueueWatchTowerDriver::removeDir( const DirId& dir_id )
170 {
171     /*
172    LOG(logDEBUG) << "INotifyWatchTower::removeDir removing inotify wd " << dir_id.wd_;
173 
174     if ( dir_id.wd_ >= 0 )
175         inotify_rm_watch( inotify_fd_, dir_id.wd_ );
176         */
177 }
178 
179 std::vector<KQueueWatchTowerDriver::KQueueObservedFile*>
180 KQueueWatchTowerDriver::waitAndProcessEvents(
181         KQueueObservedFileList* list,
182         std::unique_lock<std::mutex>* list_lock,
183         std::vector<KQueueObservedFile*>* files_needing_readding,
184         int timeout_ms )
185 {
186     std::vector<KQueueObservedFile*> files_to_notify;
187     struct kevent event;
188     struct timespec timeout = { timeout_ms / 1000, (timeout_ms % 1000) * 1000000};
189 
190     list_lock->unlock();
191     int event_count = kevent( kqueue_fd_, NULL, 0, &event, 1, timeout_ms ? &timeout : NULL );
192     list_lock->lock();
193 
194     LOG(logDEBUG) << "KQueueWatchTowerDriver::waitAndProcessEvents: event_count " << event_count;
195 
196     if ( event.flags == EV_ERROR )
197     {
198         LOG(logERROR) << "kqueue event error!";
199     }
200     else if ( event_count > 0 )
201     {
202         LOG(logDEBUG) << "kqueue event received: " << event.ident << " " <<
203             std::hex << event.filter << " " << event.flags << " " << event.fflags;
204 
205         KQueueObservedFile* file = nullptr;
206 
207         // Retrieve the file (if it was file)
208         file = list->searchByFileOrSymlinkWd( event.ident, event.ident );
209 
210         if ( file )
211         {
212             LOG(logDEBUG) << "Adding file to notify list: " << std::hex << file;
213             files_to_notify.push_back( file );
214         }
215         else
216         {
217             /* We signal all watched files in this directory, yes it is wasteful,
218              * but kqueue doesn't give us enough information so we reach for
219              * the sledgehammer rather than trying to see what has changed in this dir!
220              */
221             LOG(logDEBUG) << "File not found, is it a directory?";
222             auto files_in_dir = list->searchByDirWd( event.ident );
223             LOG(logDEBUG) << files_in_dir.size() << " files in dir.";
224             files_to_notify.reserve( files_in_dir.size() );
225             files_to_notify.insert( files_to_notify.end(), files_in_dir.begin(), files_in_dir.end() );
226         }
227     }
228     else
229     {
230         LOG(logDEBUG) << "No kevent...";
231     }
232 
233     return files_to_notify;
234 }
235 
236 void KQueueWatchTowerDriver::interruptWait()
237 {
238     char byte = 'X';
239 
240     (void) write( breaking_pipe_write_fd_, (void*) &byte, sizeof byte );
241 }
242