catch and handle errors in src/cmd/moby

Signed-off-by: Riyaz Faizullabhoy <riyaz.faizullabhoy@docker.com>

src/cmd/moby/build.go

@@ -27,7 +27,9 @@ func build(args []string) {
 	buildName := buildCmd.String("name", "", "Name to use for output files")
 	buildPull := buildCmd.Bool("pull", false, "Always pull images")
 
-	buildCmd.Parse(args)
+	if err := buildCmd.Parse(args); err != nil {
+		log.Fatal("Unable to parse args")
+	}
 	remArgs := buildCmd.Args()
 
 	if len(remArgs) == 0 {

src/cmd/moby/gcp.go

@@ -401,10 +401,15 @@ func (g GCPClient) ConnectToInstanceSerialPort(instance, zone string) error {
 		}
 	}
 
-	session.RequestPty("xterm", termHeight, termWidth, ssh.TerminalModes{
+	if err = session.RequestPty("xterm", termHeight, termWidth, ssh.TerminalModes{
 		ssh.ECHO: 1,
-	})
-	session.Shell()
+	}); err != nil {
+		return err
+	}
+
+	if err = session.Shell(); err != nil {
+		return err
+	}
 
 	err = session.Wait()
 	//exit <- true

src/cmd/moby/image.go

@@ -79,7 +79,9 @@ func tarPrefix(path string, tw *tar.Writer) error {
 			Mode:     0755,
 			Typeflag: tar.TypeDir,
 		}
-		tw.WriteHeader(hdr)
+		if err := tw.WriteHeader(hdr); err != nil {
+			return err
+		}
 		mkdir = mkdir + "/"
 	}
 	return nil
@@ -118,21 +120,37 @@ func imageTar(image, prefix string, tw *tar.Writer) error {
 		}
 		if exclude[hdr.Name] {
 			log.Debugf("image tar: %s %s exclude %s", image, prefix, hdr.Name)
-			io.Copy(ioutil.Discard, tr)
+			_, err = io.Copy(ioutil.Discard, tr)
+			if err != nil {
+				return err
+			}
 		} else if replace[hdr.Name] != "" {
 			contents := replace[hdr.Name]
 			hdr.Size = int64(len(contents))
 			hdr.Name = prefix + hdr.Name
 			log.Debugf("image tar: %s %s add %s", image, prefix, hdr.Name)
-			tw.WriteHeader(hdr)
+			if err := tw.WriteHeader(hdr); err != nil {
+				return err
+			}
 			buf := bytes.NewBufferString(contents)
-			io.Copy(tw, buf)
-			io.Copy(ioutil.Discard, tr)
+			_, err = io.Copy(tw, buf)
+			if err != nil {
+				return err
+			}
+			_, err = io.Copy(ioutil.Discard, tr)
+			if err != nil {
+				return err
+			}
 		} else {
 			log.Debugf("image tar: %s %s add %s", image, prefix, hdr.Name)
 			hdr.Name = prefix + hdr.Name
-			tw.WriteHeader(hdr)
-			io.Copy(tw, tr)
+			if err := tw.WriteHeader(hdr); err != nil {
+				return err
+			}
+			_, err = io.Copy(tw, tr)
+			if err != nil {
+				return err
+			}
 		}
 	}
 	err = tw.Close()

src/cmd/moby/run_gcp.go

@@ -41,7 +41,9 @@ func runGcp(args []string) {
 	publicFlag := gcpCmd.Bool("public", false, "Select if file on GS should be public. *Optional* when 'prefix' is a filename")
 	familyFlag := gcpCmd.String("family", "", "GCP Image Family. A group of images where the family name points to the most recent image. *Optional* when 'prefix' is a filename")
 	nameFlag := gcpCmd.String("img-name", "", "Overrides the Name used to identify the file in Google Storage, Image and Instance. Defaults to [name]")
-	gcpCmd.Parse(args)
+	if err := gcpCmd.Parse(args); err != nil {
+		log.Fatal("Unable to parse args")
+	}
 
 	remArgs := gcpCmd.Args()
 	if len(remArgs) == 0 {

src/cmd/moby/run_hyperkit.go

@@ -30,7 +30,9 @@ func runHyperKit(args []string) {
 	data := hyperkitCmd.String("data", "", "Metadata to pass to VM (either a path to a file or a string)")
 	ipStr := hyperkitCmd.String("ip", "", "IP address for the VM")
 
-	hyperkitCmd.Parse(args)
+	if err := hyperkitCmd.Parse(args); err != nil {
+		log.Fatal("Unable to parse args")
+	}
 	remArgs := hyperkitCmd.Args()
 	if len(remArgs) == 0 {
 		fmt.Println("Please specify the prefix to the image to boot\n")
@@ -59,7 +61,9 @@ func runHyperKit(args []string) {
 		if err != nil {
 			log.Fatalf("Cannot write user data ISO: %v", err)
 		}
-		outfh.Close()
+		if err = outfh.Close(); err != nil {
+			log.Fatalf("Cannot close output ISO: %v", err)
+		}
 	}
 
 	uuidStr := ""

src/cmd/moby/run_qemu.go

@@ -36,7 +36,9 @@ func runQemu(args []string) {
 	qemuCPUs := qemuFlags.String("cpus", "1", "Number of CPUs")
 	qemuMem := qemuFlags.String("mem", "1024", "Amount of memory in MB")
 
-	qemuFlags.Parse(args)
+	if err := qemuFlags.Parse(args); err != nil {
+		log.Fatal("Unable to parse args")
+	}
 	remArgs := qemuFlags.Args()
 
 	if len(remArgs) == 0 {

src/cmd/moby/run_vmware.go

@@ -70,7 +70,9 @@ func runVMware(args []string) {
 	runMem := vmwareArgs.Int("mem", 1024, "Amount of memory in MB")
 	runDisk := vmwareArgs.String("disk", "", "Path to disk image to use")
 
-	vmwareArgs.Parse(args)
+	if err := vmwareArgs.Parse(args); err != nil {
+		log.Fatal("Unable to parse args")
+	}
 	remArgs := vmwareArgs.Args()
 
 	if len(remArgs) == 0 {