Initial commit

.gitignore

@@ -1,2 +1,4 @@
+testing/
+
 .zig-cache/
 zig-out/

README.md

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+# zig-squashfs
+
+Messing around with zig via making a squashfs library. May amount to something. Or not.

inode.zig

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+pub const InodeRef = packed struct {
+    _: u16,
+    block_start: u32,
+    offset: u16,
+};
+
+const InodeType = enum(u16) {
+    dir = 1,
+    file,
+    symlink,
+    block_device,
+    char_device,
+    fifo,
+    socket,
+    ext_dir,
+    ext_file,
+    ext_symlink,
+    ext_block_device,
+    ext_char_device,
+    ext_fifo,
+    ext_socket,
+};
+
+pub const InodeHeader = packed struct {
+    inode_type: InodeType,
+    perm: u16,
+    uid_index: u16,
+    gid_index: u16,
+    mod_time: u32,
+    inode_num: u32,
+};
+
+const itypes = @import("inode_types.zig");
+
+const InodeData = union(enum) {
+    dir: itypes.DirInode,
+    file: itypes.FileInode,
+    symlink: itypes.SymlinkInode,
+    block_device: itypes.DeviceInode,
+    char_device: itypes.DeviceInode,
+    fifo: itypes.FifoInode,
+    socket: itypes.FifoInode,
+    ext_dir: itypes.ExtDirInode,
+    ext_file: itypes.ExtFileInode,
+    ext_symlink: itypes.ExtSymlinkInode,
+    ext_block_device: itypes.ExtDeviceInode,
+    ext_char_device: itypes.ExtDeviceInode,
+    ext_fifo: itypes.ExtFifoInode,
+    ext_socket: itypes.ExtFifoInode,
+};

inode_types.zig

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+pub const DirInode = packed struct {
+    dir_block_start: u32,
+    hard_links: u32,
+    dir_table_size: u16,
+    dir_block_offset: u16,
+    parent_inode_num: u32,
+};
+
+pub const DirIndexStart = packed struct {
+    dir_header_offset: u32,
+    dir_table_offset: u32,
+    name_size: u32,
+};
+
+pub const DirIndex = struct {
+    start: DirIndexStart,
+    name: []const u8,
+};
+
+pub const ExtDirInodeStart = packed struct {
+    hard_links: u32,
+    dir_table_size: u32,
+    dir_block_start: u32,
+    parent_inode_num: u32,
+    dir_index_count: u16,
+    dir_block_offset: u16,
+    xattr_index: u32,
+};
+
+pub const ExtDirInode = struct {
+    start: ExtDirInodeStart,
+    indexes: []const u8,
+};
+
+pub const FileInodeStart = packed struct {
+    start: u32,
+    frag_index: u32,
+    frag_block_offset: u32,
+    size: u32,
+};
+
+pub const FileInode = struct {
+    start: FileInodeStart,
+    block_sizes: []const u32,
+};
+
+pub const ExtFileInodeStart = packed struct {
+    start: u64,
+    size: u64,
+    sparse: u64,
+    hard_links: u32,
+    frag_index: u32,
+    frag_block_offset: u32,
+    xattr_index: u32,
+};
+
+pub const ExtFileInode = struct {
+    start: ExtFileInodeStart,
+    block_sizes: []const u32,
+};

squashfs.zig

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+const std = @import("std");
+const io = std.io;
+const Superblock = @import("superblock.zig").Superblock;
+
+pub const Reader = struct {
+    super: Superblock,
+    rdr: io.AnyReader,
+};
+
+pub fn newReader(rdr: io.AnyReader) !Reader {
+    const super = try rdr.readStruct(Superblock);
+    try super.valid();
+    return Reader{
+        .super = super,
+        .rdr = rdr,
+    };
+}

superblock.zig

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+const std = @import("std");
+
+pub const SuperblockError = error{
+    InvalidMagic,
+    InvalidLog,
+    InvalidVersion,
+};
+
+pub const Superblock = packed struct {
+    magic: u32,
+    count: u32,
+    mod_time: u32,
+    block_size: u32,
+    frags: u32,
+    comp: u16,
+    block_log: u16,
+    flags: packed struct {
+        inode_uncomp: bool,
+        data_uncomp: bool,
+        _unused: bool,
+        frag_uncomp: bool,
+        frag_always: bool,
+        data_dedupe: bool,
+        export_table: bool,
+        xattr_uncomp: bool,
+        no_xattr: bool,
+        comp_options: bool,
+        id_uncomp: bool,
+        _padding: u5,
+    },
+    id_count: u16,
+    ver_maj: u16,
+    ver_min: u16,
+    root_inode: @import("inode.zig").InodeRef,
+    size: u64,
+    id_table: u64,
+    xattr_table: u64,
+    inode_table: u64,
+    dir_table: u64,
+    frag_table: u64,
+    export_table: u64,
+
+    pub fn valid(self: Superblock) SuperblockError!void {
+        if (self.magic != 0x73717368) {
+            return SuperblockError.InvalidMagic;
+        } else if (self.block_log != std.math.log2(self.block_size)) {
+            return SuperblockError.InvalidLog;
+        } else if (self.ver_maj != 4 or self.ver_min != 0) {
+            return SuperblockError.InvalidVersion;
+        }
+    }
+};

test_squashfs.zig

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+const std = @import("std");
+const debug = std.debug;
+const squashfs = @import("squashfs.zig");
+
+const testFileName = "testing/LinuxPATest.sfs";
+
+test "open test file" {
+    const testFile = try std.fs.cwd().openFile(
+        testFileName,
+        .{},
+    );
+    defer testFile.close();
+    const reader = try squashfs.newReader(testFile.reader().any());
+    _ = reader;
+}