Caleb J. Gardner
114 lines
4.3 KiB
Zig
114 lines
4.3 KiB
Zig
//! A squashfs archive read from a file.
|
|
//! Can be used to directly access File's contents or extract to the filesystem.
|
|
|
|
const std = @import("std");
|
|
const File = std.fs.File;
|
|
const builtin = @import("builtin");
|
|
|
|
const Decomp = @import("decomp.zig");
|
|
const ExtractionOptions = @import("options.zig");
|
|
const Inode = @import("inode.zig");
|
|
const InodeRef = Inode.Ref;
|
|
const BlockSize = @import("inode_data/file.zig").BlockSize;
|
|
const SfsFile = @import("file.zig");
|
|
const Superblock = @import("super.zig").Superblock;
|
|
const Table = @import("table.zig").Table;
|
|
const MetadataReader = @import("util/metadata.zig");
|
|
const OffsetFile = @import("util/offset_file.zig");
|
|
|
|
const config = if (builtin.is_test) .{
|
|
.use_c_libs = true,
|
|
.allow_lzo = false,
|
|
} else @import("config");
|
|
|
|
/// Information about a fragment section. Multiple fragments are contained in the block described by a single FragEntry.
|
|
/// The offset into the block and fragment size is stored in the file's inode.
|
|
pub const FragEntry = packed struct {
|
|
start: u64,
|
|
size: BlockSize,
|
|
_: u32,
|
|
};
|
|
|
|
const Archive = @This();
|
|
|
|
fil: OffsetFile,
|
|
|
|
super: Superblock,
|
|
|
|
decomp: Decomp.DecompFn,
|
|
|
|
frag_table: Table(FragEntry),
|
|
id_table: Table(u16),
|
|
export_table: Table(InodeRef),
|
|
|
|
/// Begin reading a squashfs archive from the given File at the given offset.
|
|
pub fn init(fil: File, offset: u64) !Archive {
|
|
var super: Superblock = undefined;
|
|
_ = try fil.pread(@ptrCast(&super), offset);
|
|
try super.validate();
|
|
const decomp: Decomp.DecompFn = switch (super.compression) {
|
|
.gzip => Decomp.gzipDecompress,
|
|
.lzma => Decomp.lzmaDecompress,
|
|
.xz => Decomp.xzDecompress,
|
|
.zstd => Decomp.zstdDecompress,
|
|
.lz4 => if (config.use_c_libs) Decomp.cLz4 else return error.Lz4Unsupported,
|
|
.lzo => if (config.use_c_libs and config.allow_lzo) Decomp.lzoDecompress else return error.LzoUnsupported,
|
|
};
|
|
const offset_fil: OffsetFile = .init(fil, offset);
|
|
return .{
|
|
.fil = offset_fil,
|
|
.super = super,
|
|
|
|
.decomp = decomp,
|
|
|
|
.frag_table = .init(offset_fil, decomp, super.frag_start, super.frag_count),
|
|
.id_table = .init(offset_fil, decomp, super.id_start, super.id_count),
|
|
.export_table = .init(offset_fil, decomp, super.export_start, super.inode_count),
|
|
};
|
|
}
|
|
|
|
pub fn inode(self: Archive, num: u32) !Inode {
|
|
if (!self.setup) try self.setupValues();
|
|
const ref = try self.export_table.get(num - 1);
|
|
var rdr = try self.fil.readerAt(ref.block_start + self.super.inode_start, &[0]u8{});
|
|
var meta: MetadataReader = .init(self.alloc, &rdr.interface, &self.decomp);
|
|
try meta.interface.discardAll(ref.block_offset);
|
|
return try .read(self.alloc, &meta.interface, self.super.block_size);
|
|
}
|
|
|
|
pub fn root(self: Archive, alloc: std.mem.Allocator) !SfsFile {
|
|
var rdr = try self.fil.readerAt(self.super.root_ref.block_start + self.super.inode_start, &[0]u8{});
|
|
var meta: MetadataReader = .init(alloc, &rdr.interface, self.decomp);
|
|
try meta.interface.discardAll(self.super.root_ref.block_offset);
|
|
const in: Inode = try .read(alloc, &meta.interface, self.super.block_size);
|
|
return .init(alloc, self, in, "");
|
|
}
|
|
|
|
pub fn open(self: Archive, alloc: std.mem.Allocator, path: []const u8) !SfsFile {
|
|
var root_fil = try self.root(alloc);
|
|
defer if (!SfsFile.pathIsSelf(path)) root_fil.deinit();
|
|
return root_fil.open(alloc, path);
|
|
}
|
|
|
|
pub fn extract(self: Archive, alloc: std.mem.Allocator, path: []const u8, options: ExtractionOptions) !void {
|
|
var ext_path: []u8 = undefined;
|
|
if (std.fs.cwd().statFile(path)) |stat| {
|
|
if (stat.kind == .directory) {
|
|
ext_path = @constCast(path);
|
|
} else return error.ExtractionPathExists;
|
|
} else |err| {
|
|
if (err == error.FileNotFound) {
|
|
ext_path = @constCast(path);
|
|
} else {
|
|
std.log.err("Error stat-ing extraction path {s}: {}\n", .{ path, err });
|
|
return err;
|
|
}
|
|
}
|
|
defer if (ext_path.len > path.len) alloc.free(ext_path);
|
|
var rdr = try self.fil.readerAt(self.super.root_ref.block_start + self.super.inode_start, &[0]u8{});
|
|
var meta: MetadataReader = .init(alloc, &rdr.interface, self.decomp);
|
|
try meta.interface.discardAll(self.super.root_ref.block_offset);
|
|
const in: Inode = try .read(alloc, &meta.interface, self.super.block_size);
|
|
try in.extractTo(alloc, self, ext_path, options);
|
|
}
|