Starting on writing the library

Currently just parses the superblock (but that works!)
2020-11-10 05:54:49 -06:00
parent 40541575f8
commit 630e6e0f7c
10 changed files with 2232 additions and 2094 deletions
@@ -1,24 +1,59 @@
 package squashfs

+//Superblock is a raw representation of a squashfs
 //Descriptions provided by https://dr-emann.github.io/squashfs/
-type superblock struct {
-	Magic               uint32 //Magic will be 0x73717368 if it's a legit Squashfs filesystem
-	Inodes              uint32 //Inodes is the number of inodes in the inodes table
-	MkfsTime            int32  //MkfsTime is when archive was created
-	BlockSize           uint32 //BlockSize is the size of data blocks in bytes
-	Fragments           uint32 //Fragments is the number of entries in fragment table
-	Compression         uint16 //Compression is what type of compression is used
-	BlockLog            uint16 //BlockLog should be log base 2 of BlockSize. If not then the squash might be corrupt
-	Flags               uint16 //Flags are the superblock's flags
-	IDCount             uint16 //IDCount is the number of IDs in the id lookup table
-	Major               uint16
-	Minor               uint16
-	RootInode           Inode
-	BytesUsed           int64
-	IDTableStart        int64
-	XattrIDTableStart   int64
-	InodeTableStart     int64
-	DirectoryTableStart int64
-	FragmentTableStart  int64
-	LookupTableStart    int64
+type Superblock struct {
+	Magic                uint32 //Magic will be 0x73717368 if it's a legit Squashfs filesystem
+	Inodes               uint32 //Inodes is the number of inodes in the inodes table
+	MkfsTime             uint32 //MkfsTime is when archive was created
+	BlockSize            uint32 //BlockSize is the size of data blocks in bytes
+	Fragments            uint32 //Fragments is the number of entries in fragment table
+	Compression          uint16 //Compression is what type of compression is used
+	BlockLog             uint16 //BlockLog should be log base 2 of BlockSize. If not then the squash might be corrupt
+	Flags                uint16 //Flags are the superblock's flags
+	IDCount              uint16 //IDCount is the number of IDs in the id lookup table
+	Major                uint16 //Major version of squashfs format
+	Minor                uint16 //Minor version of squashfs format
+	RootInode            uint64 //RootInode is a reference to the root of the squashfs
+	BytesUsed            uint64 //BytesUsed is how many bytes the archive is. squashfs archives are often padded to 4KB.
+	IDTableOffset        uint64 //IDTableOff is the byte offset of the IDTable
+	XattrIDTableOffset   uint64 //XattrIDTableOffset is the byte offset of the xattr id table
+	InodeTableOffset     uint64 //InodeTableOffset is the byte offset of the inode table
+	DirectoryTableOffset uint64 //DirectoryTableOffset is the byte offset of the directory table
+	FragmentTableOffset  uint64 //FragmentTableOffset is the byte offset of the fragment table
+	ExportTableOffset    uint64 //ExportTableOffset is the byte offset of the export table
+}
+
+//SuperblockFlags is a parsed list of options set in Superblock.Flags
+type SuperblockFlags struct {
+	UncompressedInodes    bool
+	UncompressedData      bool
+	Check                 bool //Check is unused in current versions of squashfs
+	UncompressedFragments bool
+	NoFragments           bool
+	AlwaysFragments       bool
+	Duplicates            bool //Identical files are stored only once
+	Exportable            bool
+	UncompressedXattrs    bool
+	NoXattrs              bool
+	CompressorOptions     bool
+	UncompressedIDs       bool
+}
+
+//GetFlags returns the Flags parsed into a SuperblockFlags
+func (s *Superblock) GetFlags() SuperblockFlags {
+	return SuperblockFlags{
+		UncompressedInodes:    s.Flags&0x1 == 0x1,
+		UncompressedData:      s.Flags&0x2 == 0x2,
+		Check:                 s.Flags&0x4 == 0x4,
+		UncompressedFragments: s.Flags&0x8 == 0x8,
+		NoFragments:           s.Flags&0x10 == 0x10,
+		AlwaysFragments:       s.Flags&0x20 == 0x20,
+		Duplicates:            s.Flags&0x40 == 0x40,
+		Exportable:            s.Flags&0x80 == 0x80,
+		UncompressedXattrs:    s.Flags&0x100 == 0x100,
+		NoXattrs:              s.Flags&0x200 == 0x200,
+		CompressorOptions:     s.Flags&0x400 == 0x400,
+		UncompressedIDs:       s.Flags&0x800 == 0x800,
+	}
 }