veyron/lib/exec: adding support for passing callback endpoint and
nonce to the child process
Change-Id: Ia161ac70bac47f4f3d06de792a21391825ea2dc3
diff --git a/lib/exec/child.go b/lib/exec/child.go
index 676beb2..f200751 100644
--- a/lib/exec/child.go
+++ b/lib/exec/child.go
@@ -1,54 +1,81 @@
package exec
import (
+ "encoding/binary"
"errors"
+ "io"
"os"
)
var (
ErrNoVersion = errors.New(versionVariable + " environment variable missing")
- ErrUnsupportedVersion = errors.New("Unsupported version of veyron/runtimes/google/lib/exec request by " + versionVariable + " environment variable")
+ ErrUnsupportedVersion = errors.New("Unsupported version of veyron/lib/exec request by " + versionVariable + " environment variable")
)
type ChildHandle struct {
- // A Secret passed to the child by its parent via a trusted channel
- Secret string
+ // Endpoint is a callback endpoint that can be use to notify the
+ // parent that the child has started up successfully via the
+ // Callback() RPC.
+ Endpoint string
+ // ID is a callback ID that can be used by a parent to identify this
+ // child when the child invokes the Callback() RPC using the
+ // callback endpoint.
+ ID string
+ // Secret is a secret passed to the child by its parent via a
+ // trusted channel.
+ Secret string
+ // statusPipe is a pipe that is used to notify the parent that the
+ // child process has started successfully. Unlike the Callback()
+ // RPC, which is to be invoked by the application to notify the
+ // parent that the application is "ready", the statusPipe is to be
+ // invoked by the veyron framework to notify the parent that the
+ // child process has successfully started.
statusPipe *os.File
}
-// fileOffset accounts for the file descriptors that are always passed to the
-// child by the parent: stderr, stdin, stdout, token read, and status write.
-// Any extra files added by the client will follow fileOffset.
+// fileOffset accounts for the file descriptors that are always passed
+// to the child by the parent: stderr, stdin, stdout, data read, and
+// status write. Any extra files added by the client will follow
+// fileOffset.
const fileOffset = 5
// NewChildHandle creates a new ChildHandle that can be used to signal
// that the child is 'ready' (by calling SetReady) to its parent. The
-// value of the ChildHandle's Secret securely passed to it by the parent; this
-// is intended for subsequent use to create a secure communication channels
-// and or authentication.
+// value of the ChildHandle's Secret securely passed to it by the
+// parent; this is intended for subsequent use to create a secure
+// communication channels and or authentication.
//
-// If the child is relying on exec.Cmd.ExtraFiles then its first file descriptor
-// will not be 3, but will be offset by extra files added by the framework. The
-// developer should use the NewExtraFile method to robustly get their extra
-// files with the correct offset applied.
+// If the child is relying on exec.Cmd.ExtraFiles then its first file
+// descriptor will not be 3, but will be offset by extra files added
+// by the framework. The developer should use the NewExtraFile method
+// to robustly get their extra files with the correct offset applied.
func NewChildHandle() (*ChildHandle, error) {
switch os.Getenv(versionVariable) {
case "":
return nil, ErrNoVersion
case version1:
- // TODO(cnicolaou): need to use major.minor.build format for version #s
+ // TODO(cnicolaou): need to use major.minor.build format for
+ // version #s.
default:
return nil, ErrUnsupportedVersion
}
- tokenPipe := os.NewFile(3, "token_rd")
-
- buf := make([]byte, MaxSecretSize)
- n, err := tokenPipe.Read(buf)
+ dataPipe := os.NewFile(3, "data_rd")
+ endpoint, err := readData(dataPipe)
+ if err != nil {
+ return nil, err
+ }
+ id, err := readData(dataPipe)
+ if err != nil {
+ return nil, err
+ }
+ secret, err := readData(dataPipe)
if err != nil {
return nil, err
}
c := &ChildHandle{
- Secret: string(buf[:n]),
+ Endpoint: endpoint,
+ ID: id,
+ Secret: secret,
statusPipe: os.NewFile(4, "status_wr"),
}
return c, nil
@@ -67,3 +94,19 @@
func (c *ChildHandle) NewExtraFile(i uintptr, name string) *os.File {
return os.NewFile(i+fileOffset, name)
}
+
+func readData(r io.Reader) (string, error) {
+ var l int64 = 0
+ if err := binary.Read(r, binary.BigEndian, &l); err != nil {
+ return "", err
+ }
+ var data []byte = make([]byte, l)
+ if n, err := r.Read(data); err != nil || int64(n) != l {
+ if err != nil {
+ return "", err
+ } else {
+ return "", errors.New("partial read")
+ }
+ }
+ return string(data), nil
+}
