1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
|
// Copyright 2018 The gVisor Authors.
//
// Licensed 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.
package syscalls
import (
"time"
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/sentry/kernel"
"gvisor.dev/gvisor/pkg/sentry/kernel/epoll"
ktime "gvisor.dev/gvisor/pkg/sentry/kernel/time"
"gvisor.dev/gvisor/pkg/syserror"
"gvisor.dev/gvisor/pkg/waiter"
)
// CreateEpoll implements the epoll_create(2) linux syscall.
func CreateEpoll(t *kernel.Task, closeOnExec bool) (int32, error) {
file := epoll.NewEventPoll(t)
defer file.DecRef(t)
fd, err := t.NewFDFrom(0, file, kernel.FDFlags{
CloseOnExec: closeOnExec,
})
if err != nil {
return 0, err
}
return fd, nil
}
// AddEpoll implements the epoll_ctl(2) linux syscall when op is EPOLL_CTL_ADD.
func AddEpoll(t *kernel.Task, epfd int32, fd int32, flags epoll.EntryFlags, mask waiter.EventMask, userData [2]int32) error {
// Get epoll from the file descriptor.
epollfile := t.GetFile(epfd)
if epollfile == nil {
return syserror.EBADF
}
defer epollfile.DecRef(t)
// Get the target file id.
file := t.GetFile(fd)
if file == nil {
return syserror.EBADF
}
defer file.DecRef(t)
// Extract the epollPoll operations.
e, ok := epollfile.FileOperations.(*epoll.EventPoll)
if !ok {
return syserror.EBADF
}
// Try to add the entry.
return e.AddEntry(epoll.FileIdentifier{file, fd}, flags, mask, userData)
}
// UpdateEpoll implements the epoll_ctl(2) linux syscall when op is EPOLL_CTL_MOD.
func UpdateEpoll(t *kernel.Task, epfd int32, fd int32, flags epoll.EntryFlags, mask waiter.EventMask, userData [2]int32) error {
// Get epoll from the file descriptor.
epollfile := t.GetFile(epfd)
if epollfile == nil {
return syserror.EBADF
}
defer epollfile.DecRef(t)
// Get the target file id.
file := t.GetFile(fd)
if file == nil {
return syserror.EBADF
}
defer file.DecRef(t)
// Extract the epollPoll operations.
e, ok := epollfile.FileOperations.(*epoll.EventPoll)
if !ok {
return syserror.EBADF
}
// Try to update the entry.
return e.UpdateEntry(epoll.FileIdentifier{file, fd}, flags, mask, userData)
}
// RemoveEpoll implements the epoll_ctl(2) linux syscall when op is EPOLL_CTL_DEL.
func RemoveEpoll(t *kernel.Task, epfd int32, fd int32) error {
// Get epoll from the file descriptor.
epollfile := t.GetFile(epfd)
if epollfile == nil {
return syserror.EBADF
}
defer epollfile.DecRef(t)
// Get the target file id.
file := t.GetFile(fd)
if file == nil {
return syserror.EBADF
}
defer file.DecRef(t)
// Extract the epollPoll operations.
e, ok := epollfile.FileOperations.(*epoll.EventPoll)
if !ok {
return syserror.EBADF
}
// Try to remove the entry.
return e.RemoveEntry(t, epoll.FileIdentifier{file, fd})
}
// WaitEpoll implements the epoll_wait(2) linux syscall.
func WaitEpoll(t *kernel.Task, fd int32, max int, timeout int) ([]linux.EpollEvent, error) {
// Get epoll from the file descriptor.
epollfile := t.GetFile(fd)
if epollfile == nil {
return nil, syserror.EBADF
}
defer epollfile.DecRef(t)
// Extract the epollPoll operations.
e, ok := epollfile.FileOperations.(*epoll.EventPoll)
if !ok {
return nil, syserror.EBADF
}
// Try to read events and return right away if we got them or if the
// caller requested a non-blocking "wait".
r := e.ReadEvents(max)
if len(r) != 0 || timeout == 0 {
return r, nil
}
// We'll have to wait. Set up the timer if a timeout was specified and
// and register with the epoll object for readability events.
var haveDeadline bool
var deadline ktime.Time
if timeout > 0 {
timeoutDur := time.Duration(timeout) * time.Millisecond
deadline = t.Kernel().MonotonicClock().Now().Add(timeoutDur)
haveDeadline = true
}
w, ch := waiter.NewChannelEntry(nil)
e.EventRegister(&w, waiter.EventIn)
defer e.EventUnregister(&w)
// Try to read the events again until we succeed, timeout or get
// interrupted.
for {
r = e.ReadEvents(max)
if len(r) != 0 {
return r, nil
}
if err := t.BlockWithDeadline(ch, haveDeadline, deadline); err != nil {
if err == syserror.ETIMEDOUT {
return nil, nil
}
return nil, err
}
}
}
|
