arozos/mod/filesystem/fspermission/fspermission.go

package fspermission

import (
	"errors"
	"fmt"
	"log"
	"os"
	"strconv"

	"imuslab.com/arozos/mod/filesystem"
	"imuslab.com/arozos/mod/filesystem/fsdef"
)

/*
	This module handle functions realted to local file system permission.
	Only enabling when the system is run with sudo mode

*/

func GetFilePermissions(fsh *filesystem.FileSystemHandler, file string) (string, error) {
	fshAbs := fsh.FileSystemAbstraction
	fileStat, err := fshAbs.Stat(file)
	if err != nil {
		return "", err
	}

	permission := "0000"
	permission = fmt.Sprintf("%04o", fileStat.Mode().Perm())
	return permission, nil
}

func SetFilePermisson(fsh *filesystem.FileSystemHandler, file string, permissionKey string) error {
	fshAbs := fsh.FileSystemAbstraction
	if fshAbs.FileExists(file) && filesystem.FileExists(file) {
		//This ensure this must be a local file on the system
		mode := os.FileMode(0644)
		if len(permissionKey) != 4 {
			return errors.New("Invalid File Node")
		}

		finalMode := 0
		for i := 0; i < len(permissionKey); i++ {
			thisInt, err := strconv.Atoi(string(permissionKey[i]))
			if err != nil {
				return errors.New("Failed to parse permission key")
			}
			if i == 0 {
				if thisInt != 0 {
					return errors.New("Failed to parse permission key")
				}
			} else if i == 1 {
				if thisInt > 7 {
					return errors.New("Failed to parse permission key: Permission value > 7")
				} else {
					finalMode = finalMode + thisInt*100
				}
			} else if i == 2 {
				if thisInt > 7 {
					return errors.New("Failed to parse permission key: Permission value > 7")
				} else {
					finalMode = finalMode + thisInt*10
				}
			} else if i == 3 {
				if thisInt > 7 {
					return errors.New("Failed to parse permission key: Permission value > 7")
				} else {
					finalMode = finalMode + thisInt
				}
			}
		}

		//Convert the value into a file mode
		log.Println("Updating " + file + " permission to " + strconv.Itoa(finalMode))

		//Magic way to convert dec to oct
		output, _ := strconv.ParseInt("0"+strconv.Itoa(finalMode), 8, 64)
		mode = os.FileMode(output)

		//Set its mode
		err := os.Chmod(file, mode)
		if err != nil {
			return err
		}
	} else {
		return fsdef.ErrOperationNotSupported
	}
	return nil
}