ciao-launcher, qemu: Move launchQemu to qemu

The launcher function launchQemu has been moved to the qemu package
and is now called LaunchQemu.

Signed-off-by: Mark Ryan <mark.d.ryan@intel.com>

qemu.go

@@ -0,0 +1,62 @@
+/*
+// Copyright (c) 2016 Intel Corporation
+//
+// 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 qemu
+
+import (
+	"bytes"
+	"os"
+	"os/exec"
+
+	"golang.org/x/net/context"
+)
+
+// LaunchQemu can be used to launch a new qemu instance by invoking the
+// qemu-system-x86_64 binary.
+//
+// The ctx parameter is not currently used but has been added so that the
+// signature of this function will not need to change when launch cancellation
+// is implemented.
+//
+// params is a slice of options to pass to qemu-system-x86_64 and fds is a
+// list of open file descriptors that are to be passed to the spawned qemu
+// process.
+//
+// This function writes its log output via logger parameter.
+//
+// The function will block until the launched qemu process exits.  "", nil
+// will be returned if the launch succeeds.  Otherwise a string containing
+// the contents of stderr + a Go error object will be returned.
+func LaunchQemu(ctx context.Context, params []string, fds []*os.File, logger QMPLog) (string, error) {
+	errStr := ""
+	cmd := exec.Command("qemu-system-x86_64", params...)
+	if fds != nil {
+		logger.Infof("Adding extra file %v", fds)
+		cmd.ExtraFiles = fds
+	}
+
+	var stderr bytes.Buffer
+	cmd.Stderr = &stderr
+	logger.Infof("launching qemu with: %v", params)
+
+	err := cmd.Run()
+	if err != nil {
+		logger.Errorf("Unable to launch qemu: %v", err)
+		errStr = stderr.String()
+		logger.Errorf("%s", errStr)
+	}
+	return errStr, err
+}

qmp.go

@@ -29,9 +29,6 @@ import (
 	"golang.org/x/net/context"
 )
 
-// Code to launch qemu
-// move to package and document
-
 // QMPLog is a logging interface used by the qemu package to log various
 // interesting pieces of information.  Rather than introduce a dependency
 // on a given logging package, qemu presents this interface that allows