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connect.go
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connect.go
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// SPDX-License-Identifier: MPL-2.0
/*
* Copyright (C) 2024 The Noisy Sockets Authors.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*/
package shell
import (
"context"
"errors"
"fmt"
stdio "io"
"log/slog"
"net/http"
"os"
"time"
"github.com/gorilla/websocket"
"github.com/noisysockets/noisysockets"
latestconfig "github.com/noisysockets/noisysockets/config/v1alpha2"
"github.com/noisysockets/nsh/internal/util"
"github.com/noisysockets/shell"
"github.com/noisysockets/shell/env"
"github.com/noisysockets/shell/io"
"golang.org/x/sync/errgroup"
"golang.org/x/term"
)
func Connect(ctx context.Context, logger *slog.Logger, conf *latestconfig.Config, address string) error {
logger.Debug("Opening WireGuard network")
net, err := noisysockets.OpenNetwork(logger, conf)
if err != nil {
return fmt.Errorf("failed to open WireGuard network: %w", err)
}
defer net.Close()
logger.Debug("Connecting to server", slog.String("address", address))
dialer := &websocket.Dialer{
NetDial: net.Dial,
NetDialContext: net.DialContext,
HandshakeTimeout: 45 * time.Second,
}
urlStr := fmt.Sprintf("ws://%s/shell/ws", address)
ws, _, err := dialer.Dial(urlStr, http.Header{
"Origin": []string{fmt.Sprintf("http://%s", address)},
})
if err != nil {
return fmt.Errorf("failed to connect to server: %w", err)
}
logger.Debug("Creating client")
c, err := shell.NewClient(ctx, logger, ws)
if err != nil {
return fmt.Errorf("failed to create client: %w", err)
}
// Set the terminal to raw mode.
origTermState, err := term.MakeRaw(int(os.Stdin.Fd()))
if err != nil {
return fmt.Errorf("failed to set terminal to raw mode: %w", err)
}
defer func() {
if err := term.Restore(int(os.Stdin.Fd()), origTermState); err != nil {
logger.Warn("Failed to restore terminal state", slog.Any("error", err))
}
}()
// Create a pipe so we can make stdin non-blocking.
input, inputWriter, err := os.Pipe()
if err != nil {
return fmt.Errorf("failed to create stdin pipe: %w", err)
}
defer input.Close()
// Pump stdin into the pipe (blocking in a seperate goroutine).
// We can't use errgroup here as context cancellation is not available.
go func() {
defer inputWriter.Close()
if _, err := stdio.Copy(inputWriter, os.Stdin); err != nil && !errors.Is(err, io.ErrClosedPipe) {
logger.Error("Failed to read from stdin", slog.Any("error", err))
}
}()
if err := io.SetNonblock(input); err != nil {
return fmt.Errorf("failed to set stdin file descriptor to non-blocking: %w", err)
}
output := io.NopDeadlineWriter(os.Stdout)
ctx, cancel := context.WithCancel(ctx)
g, ctx := errgroup.WithContext(ctx)
// Close the client on cancellation of the error group.
g.Go(func() error {
<-ctx.Done()
return c.Close()
})
// Catch unexpected client errors (eg. dropped connections).
g.Go(func() error {
if err := c.Wait(); err != nil {
return err
}
return context.Canceled
})
// Handle the shell exit.
onExit := func(exitStatus int) error {
if exitStatus != 0 {
logger.Debug("Shell exited with non-zero status", slog.Int("exit_status", exitStatus))
g.Go(func() error {
return util.ExitError(exitStatus)
})
} else {
cancel()
}
return nil
}
logger.Debug("Opening shell")
// Get the initial terminal dimensions.
columns, rows, err := term.GetSize(int(os.Stdin.Fd()))
if err != nil {
return fmt.Errorf("failed to get terminal size: %w", err)
}
// Request a new terminal.
env := env.FilterSafe(os.Environ())
if err := c.OpenTerminal(columns, rows, env, input, output, onExit); err != nil {
return fmt.Errorf("failed to open shell: %w", err)
}
// Listen for window change events.
windowChangeEv, err := listenForWindowChangeEvents(ctx)
if err != nil {
return fmt.Errorf("failed to listen for window change events: %w", err)
}
g.Go(func() error {
for {
select {
case <-ctx.Done():
return ctx.Err()
case <-windowChangeEv:
columns, rows, err := term.GetSize(int(os.Stdin.Fd()))
if err != nil {
return fmt.Errorf("failed to get terminal size: %w", err)
}
if err := c.ResizeTerminal(columns, rows); err != nil {
return fmt.Errorf("failed to resize PTY: %w", err)
}
logger.Debug("Resized PTY", slog.Int("columns", columns), slog.Int("rows", rows))
}
}
})
// Wait for the terminal to exit.
if err := g.Wait(); err != nil && !errors.Is(err, context.Canceled) {
return err
}
return nil
}