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tailscale/ssh/tailssh/context.go

65 lines
1.6 KiB
Go

// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tailssh
import (
"context"
"sync"
"time"
)
// sshContext is the context.Context implementation we use for SSH
// that adds a CloseWithError method. Otherwise it's just a normalish
// Context.
type sshContext struct {
underlying context.Context
cancel context.CancelFunc // cancels underlying
mu sync.Mutex
closed bool
err error
}
func newSSHContext(ctx context.Context) *sshContext {
ctx, cancel := context.WithCancel(ctx)
return &sshContext{underlying: ctx, cancel: cancel}
}
func (ctx *sshContext) CloseWithError(err error) {
ctx.mu.Lock()
defer ctx.mu.Unlock()
if ctx.closed {
return
}
ctx.closed = true
ctx.err = err
ctx.cancel()
}
func (ctx *sshContext) Err() error {
ctx.mu.Lock()
defer ctx.mu.Unlock()
return ctx.err
}
func (ctx *sshContext) Done() <-chan struct{} { return ctx.underlying.Done() }
func (ctx *sshContext) Deadline() (deadline time.Time, ok bool) { return }
func (ctx *sshContext) Value(k any) any { return ctx.underlying.Value(k) }
// userVisibleError is a wrapper around an error that implements
// SSHTerminationError, so msg is written to their session.
type userVisibleError struct {
msg string
error
}
func (ue userVisibleError) SSHTerminationMessage() string { return ue.msg }
// SSHTerminationError is implemented by errors that terminate an SSH
// session and should be written to user's sessions.
type SSHTerminationError interface {
error
SSHTerminationMessage() string
}