A pure Go implementation of an Ext4 reader with journaling support that does not require the kernel.
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assets
jbd2
.travis.yml
LICENSE
README.md
TODO
block_group_descriptor.go
block_group_descriptor_list.go
block_group_descriptor_list_test.go
block_group_descriptor_test.go
directory.go
directory_browser.go
directory_browser_test.go
directory_walk.go
directory_walk_test.go
extent.go
extent_test.go
inode.go
inode_reader.go
inode_reader_test.go
inode_test.go
superblock.go
superblock_test.go
testing_common.go

README.md

Build Status Coverage Status GoDoc

Overview

This package allows you to browse an ext4 filesystem directly. It does not use FUSE or touch the kernel, so no privileges are required.

This package also exposes the data in the journal (if one is available).

Example

Recursively walk all of the files in the filesystem:

inodeNumber := InodeRootDirectory

filepath := path.Join(assetsPath, "hierarchy_32.ext4")

f, err := os.Open(filepath)
log.PanicIf(err)

defer f.Close()

_, err = f.Seek(Superblock0Offset, io.SeekStart)
log.PanicIf(err)

sb, err := NewSuperblockWithReader(f)
log.PanicIf(err)

bgdl, err := NewBlockGroupDescriptorListWithReadSeeker(f, sb)
log.PanicIf(err)

bgd, err := bgdl.GetWithAbsoluteInode(inodeNumber)
log.PanicIf(err)

dw, err := NewDirectoryWalk(f, bgd, inodeNumber)
log.PanicIf(err)

allEntries := make([]string, 0)

for {
	fullPath, de, err := dw.Next()
	if err == io.EOF {
		break
	} else if err != nil {
		log.Panic(err)
	}

	description := fmt.Sprintf("%s: %s", fullPath, de.String())
	allEntries = append(allEntries, description)
}

sort.Strings(allEntries)

for _, entryDescription := range allEntries {
	fmt.Println(entryDescription)
}

// Output:
//
// directory1/fortune1: DirectoryEntry<NAME=[fortune1] INODE=(15) TYPE=[regular]-(1)>
// directory1/fortune2: DirectoryEntry<NAME=[fortune2] INODE=(14) TYPE=[regular]-(1)>
// directory1/fortune5: DirectoryEntry<NAME=[fortune5] INODE=(20) TYPE=[regular]-(1)>
// directory1/fortune6: DirectoryEntry<NAME=[fortune6] INODE=(21) TYPE=[regular]-(1)>
// directory1/subdirectory1/fortune3: DirectoryEntry<NAME=[fortune3] INODE=(17) TYPE=[regular]-(1)>
// directory1/subdirectory1/fortune4: DirectoryEntry<NAME=[fortune4] INODE=(18) TYPE=[regular]-(1)>
// directory1/subdirectory1: DirectoryEntry<NAME=[subdirectory1] INODE=(16) TYPE=[directory]-(2)>
// directory1/subdirectory2/fortune7: DirectoryEntry<NAME=[fortune7] INODE=(22) TYPE=[regular]-(1)>
// directory1/subdirectory2/fortune8: DirectoryEntry<NAME=[fortune8] INODE=(23) TYPE=[regular]-(1)>
// directory1/subdirectory2: DirectoryEntry<NAME=[subdirectory2] INODE=(19) TYPE=[directory]-(2)>
// directory1: DirectoryEntry<NAME=[directory1] INODE=(13) TYPE=[directory]-(2)>
// directory2/fortune10: DirectoryEntry<NAME=[fortune10] INODE=(26) TYPE=[regular]-(1)>
// directory2/fortune9: DirectoryEntry<NAME=[fortune9] INODE=(25) TYPE=[regular]-(1)>
// directory2: DirectoryEntry<NAME=[directory2] INODE=(24) TYPE=[directory]-(2)>
// lost+found: DirectoryEntry<NAME=[lost+found] INODE=(11) TYPE=[directory]-(2)>
// thejungle.txt: DirectoryEntry<NAME=[thejungle.txt] INODE=(12) TYPE=[regular]-(1)>

This example and others are documented here.

Notes

  • Modern filesystems are supported, including both 32-bit and 64-bit addressing. Obscure filesystem options may not be compatible. See the compatibility assertions in NewSuperblockWithReader.
    • 64-bit addressing should be fine, as the high addressing should likely be zero when 64-bit addressing is turned-off (which is primarily what our unit-tests test with). However, the available documentation is limited on the subject. It's specifically not clear which of the various high/low addresses are affected by the 64-bit mode.

To Do

  • Finish implementing checksum calculation and validation. Currently all checksums are readable but with no additional functionality.