diff --git a/cmd/restic/cmd_backup.go b/cmd/restic/cmd_backup.go index 798d5609c..af736d13b 100644 --- a/cmd/restic/cmd_backup.go +++ b/cmd/restic/cmd_backup.go @@ -301,7 +301,7 @@ func (opts BackupOptions) Check(gopts GlobalOptions, args []string) error { return errors.Fatal("--stdin and --files-from-raw cannot be used together") } - if len(args) > 0 && opts.StdinCommand == false { + if len(args) > 0 && !opts.StdinCommand { return errors.Fatal("--stdin was specified and files/dirs were listed as arguments") } } @@ -596,30 +596,17 @@ func runBackup(ctx context.Context, opts BackupOptions, gopts GlobalOptions, ter targetFS = localVss } - var command *exec.Cmd - var stderr io.ReadCloser if opts.Stdin || opts.StdinCommand { if !gopts.JSON { progressPrinter.V("read data from stdin") } filename := path.Join("/", opts.StdinFilename) - var closer io.ReadCloser + var closer io.ReadCloser = os.Stdin if opts.StdinCommand { - command = exec.CommandContext(ctx, args[0], args[1:]...) - stdout, err := command.StdoutPipe() + closer, err = prepareStdinCommand(ctx, args) if err != nil { return err } - stderr, err = command.StderrPipe() - if err != nil { - return err - } - if err := command.Start(); err != nil { - return err - } - closer = stdout - } else { - closer = os.Stdin } targetFS = &fs.Reader{ ModTime: timeStamp, @@ -676,8 +663,6 @@ func runBackup(ctx context.Context, opts BackupOptions, gopts GlobalOptions, ter Hostname: opts.Host, ParentSnapshot: parentSnapshot, ProgramVersion: "restic " + version, - Command: command, - CommandStderr: stderr, } if !gopts.JSON { @@ -708,3 +693,32 @@ func runBackup(ctx context.Context, opts BackupOptions, gopts GlobalOptions, ter // Return error if any return werr } + +func prepareStdinCommand(ctx context.Context, args []string) (io.ReadCloser, error) { + // Prepare command and stdout. These variables will be assigned to the + // io.ReadCloser that is used by the archiver to read data, so that the + // Close() function waits for the program to finish. See + // fs.ReadCloserCommand. + command := exec.CommandContext(ctx, args[0], args[1:]...) + stdout, err := command.StdoutPipe() + if err != nil { + return nil, errors.Wrap(err, "command.StdoutPipe") + } + + // Use a Go routine to handle the stderr to avoid deadlocks + stderr, err := command.StderrPipe() + if err != nil { + return nil, errors.Wrap(err, "command.StderrPipe") + } + go func() { + sc := bufio.NewScanner(stderr) + for sc.Scan() { + _, _ = fmt.Fprintf(os.Stderr, "subprocess %v: %v\n", command.Args[0], sc.Text()) + } + }() + + if err := command.Start(); err != nil { + return nil, errors.Wrap(err, "command.Start") + } + return &fs.ReadCloserCommand{Cmd: command, Stdout: stdout}, nil +} diff --git a/internal/archiver/archiver.go b/internal/archiver/archiver.go index 91f991e7d..98819d797 100644 --- a/internal/archiver/archiver.go +++ b/internal/archiver/archiver.go @@ -2,9 +2,7 @@ package archiver import ( "context" - "io" "os" - "os/exec" "path" "runtime" "sort" @@ -683,8 +681,6 @@ type SnapshotOptions struct { Time time.Time ParentSnapshot *restic.Snapshot ProgramVersion string - Command *exec.Cmd - CommandStderr io.ReadCloser } // loadParentTree loads a tree referenced by snapshot id. If id is null, nil is returned. @@ -796,15 +792,6 @@ func (arch *Archiver) Snapshot(ctx context.Context, targets []string, opts Snaps return nil, restic.ID{}, err } - if opts.Command != nil { - errBytes, _ := io.ReadAll(opts.CommandStderr) - cmdErr := opts.Command.Wait() - if cmdErr != nil { - debug.Log("error while executing command: %v", cmdErr) - return nil, restic.ID{}, errors.New(string(errBytes)) - } - } - sn, err := restic.NewSnapshot(targets, opts.Tags, opts.Hostname, opts.Time) if err != nil { return nil, restic.ID{}, err diff --git a/internal/fs/fs_reader_command.go b/internal/fs/fs_reader_command.go new file mode 100644 index 000000000..f35454c7f --- /dev/null +++ b/internal/fs/fs_reader_command.go @@ -0,0 +1,23 @@ +package fs + +import ( + "io" + "os/exec" +) + +// ReadCloserCommand wraps an exec.Cmd and its standard output to provide an +// io.ReadCloser that waits for the command to terminate on Close(), reporting +// any error in the command.Wait() function back to the Close() caller. +type ReadCloserCommand struct { + Cmd *exec.Cmd + Stdout io.ReadCloser +} + +func (fp *ReadCloserCommand) Read(p []byte) (n int, err error) { + return fp.Stdout.Read(p) +} + +func (fp *ReadCloserCommand) Close() error { + // No need to close fp.Stdout as Wait() closes all pipes. + return fp.Cmd.Wait() +}