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
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
|
// 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 cmd
import (
"context"
"encoding/json"
"io"
"os"
"path/filepath"
"github.com/google/subcommands"
specs "github.com/opencontainers/runtime-spec/specs-go"
"gvisor.dev/gvisor/runsc/flag"
)
func writeSpec(w io.Writer, cwd string, netns string, args []string) error {
spec := &specs.Spec{
Version: "1.0.0",
Process: &specs.Process{
Terminal: true,
User: specs.User{
UID: 0,
GID: 0,
},
Args: args,
Env: []string{
"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
"TERM=xterm",
},
Cwd: cwd,
Capabilities: &specs.LinuxCapabilities{
Bounding: []string{
"CAP_AUDIT_WRITE",
"CAP_KILL",
"CAP_NET_BIND_SERVICE",
},
Effective: []string{
"CAP_AUDIT_WRITE",
"CAP_KILL",
"CAP_NET_BIND_SERVICE",
},
Inheritable: []string{
"CAP_AUDIT_WRITE",
"CAP_KILL",
"CAP_NET_BIND_SERVICE",
},
Permitted: []string{
"CAP_AUDIT_WRITE",
"CAP_KILL",
"CAP_NET_BIND_SERVICE",
},
// TODO(gvisor.dev/issue/3166): support ambient capabilities
},
Rlimits: []specs.POSIXRlimit{
{
Type: "RLIMIT_NOFILE",
Hard: 1024,
Soft: 1024,
},
},
},
Root: &specs.Root{
Path: "rootfs",
Readonly: true,
},
Hostname: "runsc",
Mounts: []specs.Mount{
{
Destination: "/proc",
Type: "proc",
Source: "proc",
},
{
Destination: "/dev",
Type: "tmpfs",
Source: "tmpfs",
},
{
Destination: "/sys",
Type: "sysfs",
Source: "sysfs",
Options: []string{
"nosuid",
"noexec",
"nodev",
"ro",
},
},
},
Linux: &specs.Linux{
Namespaces: []specs.LinuxNamespace{
{
Type: "pid",
},
{
Type: "network",
Path: netns,
},
{
Type: "ipc",
},
{
Type: "uts",
},
{
Type: "mount",
},
},
},
}
e := json.NewEncoder(w)
e.SetIndent("", " ")
return e.Encode(spec)
}
// Spec implements subcommands.Command for the "spec" command.
type Spec struct {
bundle string
cwd string
netns string
}
// Name implements subcommands.Command.Name.
func (*Spec) Name() string {
return "spec"
}
// Synopsis implements subcommands.Command.Synopsis.
func (*Spec) Synopsis() string {
return "create a new OCI bundle specification file"
}
// Usage implements subcommands.Command.Usage.
func (*Spec) Usage() string {
return `spec [options] [-- args...] - create a new OCI bundle specification file.
The spec command creates a new specification file (config.json) for a new OCI
bundle.
The specification file is a starter file that runs the command specified by
'args' in the container. If 'args' is not specified the default is to run the
'sh' program.
While a number of flags are provided to change values in the specification, you
can examine the file and edit it to suit your needs after this command runs.
You can find out more about the format of the specification file by visiting
the OCI runtime spec repository:
https://github.com/opencontainers/runtime-spec/
EXAMPLE:
$ mkdir -p bundle/rootfs
$ cd bundle
$ runsc spec -- /hello
$ docker export $(docker create hello-world) | tar -xf - -C rootfs
$ sudo runsc run hello
`
}
// SetFlags implements subcommands.Command.SetFlags.
func (s *Spec) SetFlags(f *flag.FlagSet) {
f.StringVar(&s.bundle, "bundle", ".", "path to the root of the OCI bundle")
f.StringVar(&s.cwd, "cwd", "/", "working directory that will be set for the executable, "+
"this value MUST be an absolute path")
f.StringVar(&s.netns, "netns", "", "network namespace path")
}
// Execute implements subcommands.Command.Execute.
func (s *Spec) Execute(_ context.Context, f *flag.FlagSet, args ...interface{}) subcommands.ExitStatus {
// Grab the arguments.
containerArgs := f.Args()
if len(containerArgs) == 0 {
containerArgs = []string{"sh"}
}
confPath := filepath.Join(s.bundle, "config.json")
if _, err := os.Stat(confPath); !os.IsNotExist(err) {
Fatalf("file %q already exists", confPath)
}
configFile, err := os.OpenFile(confPath, os.O_WRONLY|os.O_CREATE, 0664)
if err != nil {
Fatalf("opening file %q: %v", confPath, err)
}
err = writeSpec(configFile, s.cwd, s.netns, containerArgs)
if err != nil {
Fatalf("writing to %q: %v", confPath, err)
}
return subcommands.ExitSuccess
}
|
