-
Notifications
You must be signed in to change notification settings - Fork 0
/
termhandlers.go
203 lines (167 loc) · 5.4 KB
/
termhandlers.go
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
/*
Copyright 2017 Gravitational, Inc.
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 srv
import (
"golang.org/x/crypto/ssh"
rsession "github.com/gravitational/teleport/lib/session"
"github.com/gravitational/teleport/lib/sshutils"
"github.com/gravitational/trace"
)
// TermHandlers are common terminal handling functions used by both the
// regular and forwarding server.
type TermHandlers struct {
SessionRegistry *SessionRegistry
}
// HandleExec handles requests of type "exec" which can execute with or
// without a TTY. Result of execution is propagated back on the ExecResult
// channel of the context.
func (t *TermHandlers) HandleExec(ch ssh.Channel, req *ssh.Request, ctx *ServerContext) error {
execRequest, err := parseExecRequest(req, ctx)
if err != nil {
return trace.Wrap(err)
}
// a terminal has been previously allocate for this command.
// run this inside an interactive session
if ctx.GetTerm() != nil {
return t.SessionRegistry.OpenSession(ch, req, ctx)
}
// otherwise, regular execution
result, err := execRequest.Start(ch)
if err != nil {
return trace.Wrap(err)
}
// if the program failed to start, we should send that result back
if result != nil {
ctx.Debugf("Exec request (%v) result: %v", execRequest, result)
ctx.SendExecResult(*result)
}
// in case if result is nil and no error, this means that program is
// running in the background
go func() {
result, err = execRequest.Wait()
if err != nil {
ctx.Errorf("Exec request (%v) wait failed: %v", execRequest, err)
}
if result != nil {
ctx.SendExecResult(*result)
}
}()
return nil
}
// HandlePTYReq handles requests of type "pty-req" which allocate a TTY for
// "exec" or "shell" requests. The "pty-req" includes the size of the TTY as
// well as the terminal type requested.
func (t *TermHandlers) HandlePTYReq(ch ssh.Channel, req *ssh.Request, ctx *ServerContext) error {
// parse and extract the requested window size of the pty
ptyRequest, err := parsePTYReq(req)
if err != nil {
return trace.Wrap(err)
}
termModes, err := ptyRequest.TerminalModes()
if err != nil {
return trace.Wrap(err)
}
params, err := rsession.NewTerminalParamsFromUint32(ptyRequest.W, ptyRequest.H)
if err != nil {
return trace.Wrap(err)
}
ctx.Debugf("Requested terminal %q of size %v", ptyRequest.Env, *params)
// get an existing terminal or create a new one
term := ctx.GetTerm()
if term == nil {
// a regular or forwarding terminal will be allocated
term, err = NewTerminal(ctx)
if err != nil {
return trace.Wrap(err)
}
ctx.SetTerm(term)
}
term.SetWinSize(*params)
term.SetTermType(ptyRequest.Env)
term.SetTerminalModes(termModes)
// update the session
if err := t.SessionRegistry.NotifyWinChange(*params, ctx); err != nil {
ctx.Errorf("Unable to update session: %v", err)
}
return nil
}
// HandleShell handles requests of type "shell" which request a interactive
// shell be created within a TTY.
func (t *TermHandlers) HandleShell(ch ssh.Channel, req *ssh.Request, ctx *ServerContext) error {
var err error
// creating an empty exec request implies a interactive shell was requested
ctx.ExecRequest, err = NewExecRequest(ctx, "")
if err != nil {
return trace.Wrap(err)
}
if err := t.SessionRegistry.OpenSession(ch, req, ctx); err != nil {
return trace.Wrap(err)
}
return nil
}
// HandleWinChange handles requests of type "window-change" which update the
// size of the TTY running on the server.
func (t *TermHandlers) HandleWinChange(ch ssh.Channel, req *ssh.Request, ctx *ServerContext) error {
params, err := parseWinChange(req)
if err != nil {
ctx.Error(err)
return trace.Wrap(err)
}
term := ctx.GetTerm()
if term != nil {
err = term.SetWinSize(*params)
if err != nil {
ctx.Errorf("Unable to set window size: %v", err)
}
}
err = t.SessionRegistry.NotifyWinChange(*params, ctx)
if err != nil {
return trace.Wrap(err)
}
return nil
}
func parseExecRequest(req *ssh.Request, ctx *ServerContext) (Exec, error) {
var err error
var r sshutils.ExecReq
if err = ssh.Unmarshal(req.Payload, &r); err != nil {
return nil, trace.Wrap(err)
}
ctx.ExecRequest, err = NewExecRequest(ctx, r.Command)
if err != nil {
return nil, trace.Wrap(err)
}
return ctx.ExecRequest, nil
}
func parsePTYReq(req *ssh.Request) (*sshutils.PTYReqParams, error) {
var r sshutils.PTYReqParams
if err := ssh.Unmarshal(req.Payload, &r); err != nil {
return nil, trace.Wrap(err)
}
// if the caller asked for an invalid sized pty (like ansible
// which asks for a 0x0 size) update the request with defaults
if err := r.CheckAndSetDefaults(); err != nil {
return nil, trace.Wrap(err)
}
return &r, nil
}
func parseWinChange(req *ssh.Request) (*rsession.TerminalParams, error) {
var r sshutils.WinChangeReqParams
if err := ssh.Unmarshal(req.Payload, &r); err != nil {
return nil, trace.Wrap(err)
}
params, err := rsession.NewTerminalParamsFromUint32(r.W, r.H)
if err != nil {
return nil, trace.Wrap(err)
}
return params, nil
}