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
|
// Copyright 2018 Google LLC
//
// 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 linux
import (
"gvisor.googlesource.com/gvisor/pkg/abi/linux"
"gvisor.googlesource.com/gvisor/pkg/sentry/arch"
"gvisor.googlesource.com/gvisor/pkg/sentry/kernel"
"gvisor.googlesource.com/gvisor/pkg/sentry/kernel/shm"
"gvisor.googlesource.com/gvisor/pkg/syserror"
)
// Shmget implements shmget(2).
func Shmget(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
key := args[0].Int()
size := uint64(args[1].SizeT())
flag := args[2].Int()
private := key == linux.IPC_PRIVATE
create := flag&linux.IPC_CREAT == linux.IPC_CREAT
exclusive := flag&linux.IPC_EXCL == linux.IPC_EXCL
mode := linux.FileMode(flag & 0777)
pid := int32(t.ThreadGroup().ID())
r := t.IPCNamespace().ShmRegistry()
segment, err := r.FindOrCreate(t, pid, key, size, mode, private, create, exclusive)
if err != nil {
return 0, nil, err
}
return uintptr(segment.ID), nil, nil
}
// findSegment retrives a shm segment by the given id.
func findSegment(t *kernel.Task, id int32) (*shm.Shm, error) {
r := t.IPCNamespace().ShmRegistry()
segment := r.FindByID(id)
if segment == nil {
// No segment with provided id.
return nil, syserror.EINVAL
}
return segment, nil
}
// Shmat implements shmat(2).
func Shmat(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
id := args[0].Int()
addr := args[1].Pointer()
flag := args[2].Int()
segment, err := findSegment(t, id)
if err != nil {
return 0, nil, syserror.EINVAL
}
opts, err := segment.ConfigureAttach(t, addr, shm.AttachOpts{
Execute: flag&linux.SHM_EXEC == linux.SHM_EXEC,
Readonly: flag&linux.SHM_RDONLY == linux.SHM_RDONLY,
Remap: flag&linux.SHM_REMAP == linux.SHM_REMAP,
})
if err != nil {
return 0, nil, err
}
defer segment.DecRef()
addr, err = t.MemoryManager().MMap(t, opts)
return uintptr(addr), nil, err
}
// Shmdt implements shmdt(2).
func Shmdt(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
addr := args[0].Pointer()
err := t.MemoryManager().DetachShm(t, addr)
return 0, nil, err
}
// Shmctl implements shmctl(2).
func Shmctl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
id := args[0].Int()
cmd := args[1].Int()
buf := args[2].Pointer()
r := t.IPCNamespace().ShmRegistry()
switch cmd {
case linux.SHM_STAT:
// Technically, we should be treating id as "an index into the kernel's
// internal array that maintains information about all shared memory
// segments on the system". Since we don't track segments in an array,
// we'll just pretend the shmid is the index and do the same thing as
// IPC_STAT. Linux also uses the index as the shmid.
fallthrough
case linux.IPC_STAT:
segment, err := findSegment(t, id)
if err != nil {
return 0, nil, syserror.EINVAL
}
stat, err := segment.IPCStat(t)
if err == nil {
_, err = t.CopyOut(buf, stat)
}
return 0, nil, err
case linux.IPC_INFO:
params := r.IPCInfo()
_, err := t.CopyOut(buf, params)
return 0, nil, err
case linux.SHM_INFO:
info := r.ShmInfo()
_, err := t.CopyOut(buf, info)
return 0, nil, err
}
// Remaining commands refer to a specific segment.
segment, err := findSegment(t, id)
if err != nil {
return 0, nil, syserror.EINVAL
}
switch cmd {
case linux.IPC_SET:
var ds linux.ShmidDS
_, err = t.CopyIn(buf, &ds)
if err != nil {
return 0, nil, err
}
err = segment.Set(t, &ds)
return 0, nil, err
case linux.IPC_RMID:
segment.MarkDestroyed()
return 0, nil, nil
case linux.SHM_LOCK, linux.SHM_UNLOCK:
// We currently do not support memmory locking anywhere.
// mlock(2)/munlock(2) are currently stubbed out as no-ops so do the
// same here.
t.Kernel().EmitUnimplementedEvent(t)
return 0, nil, nil
default:
return 0, nil, syserror.EINVAL
}
}
|
