Fixes #195 and #125 (#197)

* Added SquashfsReader()

* Fixed #195 and #125

* Added more comments to SquashfsReader

src/appimaged/desktop.go

@@ -95,7 +95,7 @@ func writeDesktopFile(ai AppImage) {
 	time.Sleep(1 * time.Second)
 	add := ""
 	args, err := ai.Args()
-	if err == nil {
+	if err == nil && len(args) > 0 {
 		add = " " + strings.Join(args, " ")
 	}
 	cfg.Section("Desktop Entry").Key("Exec").SetValue(arg0abs + " wrap \"" + ai.Path + "\"" + add) // Resolve to a full path

src/appimaged/prerequisites.go

@@ -207,16 +207,16 @@ func stopSystemdService(servicename string) {
 */
 
 func exitIfBinfmtExists(path string) {
-	cmd := exec.Command("/bin/sh", "-c", "echo -1 | sudo tee "+path)
-	cmd.Run()
-	// if err != nil {
-	// helpers.PrintError("prerequisites: exitIfBinfmtExists", err)
-	// If these binfmts are not there, that is actually not an error and should not be reported as that
-	// }
 	if _, err := os.Stat(path); err == nil {
-		log.Println("ERROR:", path, "exists. Please remove it by running")
-		println("echo -1 | sudo tee", path)
-		os.Exit(1)
+		//If path exists, try to get sudo and remove it.
+		cmd := exec.Command("/bin/sh", "-c", "echo -1 | sudo tee "+path)
+		cmd.Run()
+		if _, err := os.Stat(path); err == nil {
+			//It still exists, so we panic and quit.
+			log.Println("ERROR:", path, "exists. Please remove it by running")
+			println("echo -1 | sudo tee", path)
+			os.Exit(1)
+		}
 	}
 }
 

src/goappimage/appimage.go

@@ -4,7 +4,6 @@ import (
 	"bufio"
 	"bytes"
 	"errors"
-	"fmt"
 	"io"
 	"os"
 	"os/exec"
@@ -13,6 +12,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/CalebQ42/squashfs"
 	"github.com/probonopd/go-appimage/internal/helpers"
 	"gopkg.in/ini.v1"
 )
@@ -149,6 +149,25 @@ func (ai AppImage) determineImageType() int {
 	return -1
 }
 
+//SquashfsReader allows direct access to an AppImage's squashfs.
+//Only works on type 2 AppImages
+func (ai AppImage) SquashfsReader() (*squashfs.Reader, error) {
+	if ai.imageType != 2 {
+		return nil, errors.New("not a type 2 appimage")
+	}
+	aiFil, err := os.Open(ai.Path)
+	if err != nil {
+		return nil, err
+	}
+	stat, _ := aiFil.Stat()
+	aiRdr := io.NewSectionReader(aiFil, ai.offset, stat.Size()-ai.offset)
+	squashRdr, err := squashfs.NewSquashfsReader(aiRdr)
+	if err != nil {
+		return nil, err
+	}
+	return squashRdr, nil
+}
+
 //Type is the type of the AppImage. Should be either 1 or 2.
 func (ai AppImage) Type() int {
 	return ai.imageType
@@ -216,7 +235,6 @@ func (ai AppImage) Args() ([]string, error) {
 		return nil, errors.New("desktop file wasn't parsed")
 	}
 	var exec = ai.Desktop.Section("Desktop Entry").Key("Exec").Value()
-	fmt.Println("exec:", exec)
 	if exec == "" {
 		return nil, errors.New("exec key not present")
 	}