vorteil/vorteil

package imagetools

/**
 * SPDX-License-Identifier: Apache-2.0
 * Copyright 2020 vorteil.io Pty Ltd
 */

import (
    "crypto/md5"
    "encoding/hex"
    "fmt"
    "io"
    "strings"

    "github.com/vorteil/vorteil/pkg/vdecompiler"
)

// MDSumImageFile returns the md5sum of a imageFilePath stored in vorteilImage
func MDSumImageFile(vorteilImagePath string, imageFilePath string, seekOS bool) (string, error) {
    var rdr io.Reader
    var err error
    var md5sumOut string

    vorteilImage, err := vdecompiler.Open(vorteilImagePath)
    if err != nil {
        return md5sumOut, err
    }

    defer vorteilImage.Close()

    if seekOS {
        imageFilePath = strings.TrimPrefix(imageFilePath, "/")
        rdr, err = vorteilImage.KernelFile(imageFilePath)
    } else {
        ino, err := vorteilImage.ResolvePathToInodeNo(imageFilePath)
        if err != nil {
            return md5sumOut, err
        }

        inode, err := vorteilImage.ResolveInode(ino)
        if err == nil {
            if vdecompiler.InodeIsDirectory(inode) {
                err = fmt.Errorf("\"%s\" is not a regular file", imageFilePath)
            } else {
                rdr, err = vorteilImage.InodeReader(inode)
            }
        }

        if err != nil {
            return md5sumOut, err
        }

        rdr = io.LimitReader(rdr, int64(vdecompiler.InodeSize(inode)))
    }

    hasher := md5.New()
    _, err = io.Copy(hasher, rdr)
    if err == nil {
        md5sumOut = hex.EncodeToString(hasher.Sum(nil))
    }

    return md5sumOut, err
}