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zig-squashfs/src/inode.zig
T
Caleb J. Gardner 5f629df47c alloc-ified many functions.
Updated README
2026-02-28 22:33:57 -06:00

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Zig

//! A file-system object. Represents a File or directory.
const std = @import("std");
const Reader = std.Io.Reader;
const WaitGroup = std.Thread.WaitGroup;
const Pool = std.Thread.Pool;
const Mutex = std.Thread.Mutex;
const Archive = @import("archive.zig");
const DirEntry = @import("dir_entry.zig");
const ExtractionOptions = @import("options.zig");
const dir = @import("inode_data/dir.zig");
const file = @import("inode_data/file.zig");
const misc = @import("inode_data/misc.zig");
const DataReader = @import("util/data.zig");
const ThreadedDataReader = @import("util/data_threaded.zig");
const MetadataReader = @import("util/metadata.zig");
pub const Ref = packed struct {
block_offset: u16,
block_start: u32,
_: u16,
};
pub const InodeType = enum(u16) {
dir = 1,
file,
symlink,
block_dev,
char_dev,
fifo,
socket,
ext_dir,
ext_file,
ext_symlink,
ext_block_dev,
ext_char_dev,
ext_fifo,
ext_socket,
};
pub const InodeData = union(InodeType) {
dir: dir.Dir,
file: file.File,
symlink: misc.Symlink,
block_dev: misc.Dev,
char_dev: misc.Dev,
fifo: misc.IPC,
socket: misc.IPC,
ext_dir: dir.ExtDir,
ext_file: file.ExtFile,
ext_symlink: misc.ExtSymlink,
ext_block_dev: misc.ExtDev,
ext_char_dev: misc.ExtDev,
ext_fifo: misc.ExtIPC,
ext_socket: misc.ExtIPC,
};
pub const Header = packed struct {
inode_type: InodeType,
permissions: u16,
uid_idx: u16,
gid_idx: u16,
mod_time: u32,
num: u32,
};
const Inode = @This();
hdr: Header,
data: InodeData,
pub fn read(alloc: std.mem.Allocator, rdr: *Reader, block_size: u32) !Inode {
var hdr: Header = undefined;
try rdr.readSliceEndian(Header, @ptrCast(&hdr), .little);
return .{
.hdr = hdr,
.data = switch (hdr.inode_type) {
.dir => .{ .dir = try .read(rdr) },
.file => .{ .file = try .read(alloc, rdr, block_size) },
.symlink => .{ .symlink = try .read(alloc, rdr) },
.block_dev => .{ .block_dev = try .read(rdr) },
.char_dev => .{ .char_dev = try .read(rdr) },
.fifo => .{ .fifo = try .read(rdr) },
.socket => .{ .socket = try .read(rdr) },
.ext_dir => .{ .ext_dir = try .read(rdr) },
.ext_file => .{ .ext_file = try .read(alloc, rdr, block_size) },
.ext_symlink => .{ .ext_symlink = try .read(alloc, rdr) },
.ext_block_dev => .{ .ext_block_dev = try .read(rdr) },
.ext_char_dev => .{ .ext_char_dev = try .read(rdr) },
.ext_fifo => .{ .ext_fifo = try .read(rdr) },
.ext_socket => .{ .ext_socket = try .read(rdr) },
},
};
}
pub fn readFromEntry(alloc: std.mem.Allocator, archive: *Archive, entry: DirEntry) !Inode {
var rdr = try archive.fil.readerAt(archive.super.inode_start + entry.block_start, &[0]u8{});
var meta: MetadataReader = .init(alloc, &rdr.interface, archive.decomp);
try meta.interface.discardAll(entry.block_offset);
return read(alloc, &meta.interface, archive.super.block_size);
}
pub fn deinit(self: Inode, alloc: std.mem.Allocator) void {
switch (self.data) {
.file => |f| alloc.free(f.block_sizes),
.ext_file => |f| alloc.free(f.block_sizes),
.symlink => |s| alloc.free(s.target),
.ext_symlink => |s| alloc.free(s.target),
else => {},
}
}
/// Get the data reader for a file inode.
pub fn dataReader(self: Inode, alloc: std.mem.Allocator, archive: *Archive) !DataReader {
return switch (self.hdr.inode_type) {
.file => readerFromData(alloc, archive, self.data.file),
.ext_file => readerFromData(alloc, archive, self.data.ext_file),
else => error.NotRegularFile,
};
}
fn readerFromData(alloc: std.mem.Allocator, archive: *Archive, data: anytype) !DataReader {
var out: DataReader = .init(alloc, archive.*, data.block_sizes, data.block_start, data.size);
if (data.frag_idx != 0xFFFFFFFF)
out.addFragment(try archive.frag_table.get(data.frag_idx), data.frag_block_offset);
return out;
}
/// Get a threaded data reader for a file inode.
pub fn threadedDataReader(self: Inode, alloc: std.mem.Allocator, archive: *Archive) !ThreadedDataReader {
return switch (self.hdr.inode_type) {
.file => threadedReaderFromData(alloc, archive, self.data.file),
.ext_file => threadedReaderFromData(alloc, archive, self.data.ext_file),
else => error.NotRegularFile,
};
}
fn threadedReaderFromData(alloc: std.mem.Allocator, archive: *Archive, data: anytype) !ThreadedDataReader {
var out: ThreadedDataReader = .init(alloc, archive.*, data.block_sizes, data.block_start, data.size);
if (data.frag_idx != 0xFFFFFFFF)
out.addFragment(try archive.frag_table.get(data.frag_idx), data.frag_block_offset);
return out;
}
/// Get the directory entries for a directory inode.
pub fn dirEntries(self: Inode, alloc: std.mem.Allocator, archive: Archive) ![]DirEntry {
return switch (self.hdr.inode_type) {
.dir => entriesFromData(alloc, archive, self.data.dir),
.ext_dir => entriesFromData(alloc, archive, self.data.ext_dir),
else => error.NotDirectory,
};
}
fn entriesFromData(alloc: std.mem.Allocator, archive: Archive, data: anytype) ![]DirEntry {
var rdr = try archive.fil.readerAt(archive.super.dir_start + data.block_start, &[0]u8{});
var meta: MetadataReader = .init(alloc, &rdr.interface, archive.decomp);
try meta.interface.discardAll(data.block_offset);
return DirEntry.readDir(alloc, &meta.interface, data.size);
}
/// Extract the inode to the given path. Single threaded.
pub fn extractTo(self: Inode, alloc: std.mem.Allocator, archive: *Archive, path: []const u8, options: ExtractionOptions) !void {
if (options.threads > 1) return self.extractToThreaded(alloc, archive, path, options);
switch (self.hdr.inode_type) {
.dir, .ext_dir => {
// Removing any trailing separators since that's the easiest path forward.
if (path[path.len - 1] == '/') return self.extractTo(alloc, archive, path[0 .. path.len - 1], options);
std.fs.cwd().makeDir(path) catch |err| {
if (err != std.fs.Dir.MakeError.PathAlreadyExists) return err;
};
const entries = try self.dirEntries(alloc, archive.*);
defer {
for (entries) |entry| entry.deinit(alloc);
alloc.free(entries);
}
for (entries) |entry| {
var new_path = try alloc.alloc(u8, path.len + 1 + entry.name.len);
@memcpy(new_path[0..path.len], path);
@memcpy(new_path[path.len + 1 ..], entry.name);
new_path[path.len] = '/';
defer alloc.free(new_path);
var inode: Inode = try readFromEntry(alloc, archive, entry);
defer inode.deinit(alloc);
try inode.extractTo(alloc, archive, new_path, options);
}
},
.file, .ext_file => try self.extractRegFile(alloc, archive, path, options),
.symlink, .ext_symlink => try self.extractSymlink(path),
else => try self.extractDevice(archive, path, options),
}
}
const Parent = struct {
alloc: std.mem.Allocator,
path: []const u8,
uid: u16,
gid: u16,
perm: u16,
mod_time: u32,
ignore_permissions: bool,
ignore_xattr: bool,
wg: WaitGroup = .{},
mut: Mutex = .{},
fn create(alloc: std.mem.Allocator, hdr: Header, archive: *Archive, path: []const u8, options: ExtractionOptions, dir_size: usize) !*Parent {
const out = try alloc.create(Parent);
errdefer alloc.destroy(out);
out.* = .{
.alloc = alloc,
.path = path,
.uid = try archive.id_table.get(hdr.uid_idx),
.gid = try archive.id_table.get(hdr.gid_idx),
.perm = hdr.permissions,
.mod_time = hdr.mod_time,
.ignore_permissions = options.ignore_permissions,
.ignore_xattr = options.ignore_xattr,
};
out.wg.startMany(dir_size);
return out;
}
fn finish(p: *Parent) !void {
p.mut.lock();
{
defer p.mut.unlock();
p.wg.finish();
if (!p.wg.isDone()) return;
}
defer p.alloc.destroy(p);
var fil = try std.fs.cwd().openFile(p.path, .{});
defer fil.close();
const time = @as(i128, p.mod_time) * 1000000000;
try fil.updateTimes(time, time);
if (p.ignore_permissions) {
try fil.chmod(p.perm);
try fil.chown(p.uid, p.gid);
}
}
};
/// Extract the inode to the given path. Multi-threaded.
/// Functions identically to extractTo on all but regular files and directories.
///
/// If threads <= 1, then this just calls extractTo.
fn extractToThreaded(self: Inode, allocator: std.mem.Allocator, archive: *Archive, path: []const u8, options: ExtractionOptions) !void {
switch (self.hdr.inode_type) {
.dir, .ext_dir => {
// Removing any trailing separators since that's the easiest path forward.
if (path[path.len - 1] == '/') return self.extractToThreaded(allocator, archive, path[0 .. path.len - 1], options);
// Fixed Allocator
// const mem_buf = archive.allocator().alloc(u8, 2 * 1024 * 1024 * 1024);
// defer archive.allocator().free(mem_buf);
// var fixed_alloc: std.heap.FixedBufferAllocator = .init(mem_buf);
// const alloc = fixed_alloc.threadSafeAllocator();
// Arena Allocator
var arena_alloc: std.heap.ArenaAllocator = .init(allocator);
defer arena_alloc.deinit();
var thread_alloc: std.heap.ThreadSafeAllocator = .{ .child_allocator = arena_alloc.allocator() };
const alloc = thread_alloc.allocator();
var wg: WaitGroup = .{};
// defer if(!options.ignore_permissions) perms.?.deinit(alloc); We don't need to do this due to ArenaAllocator
var pool: Pool = undefined;
try pool.init(.{ .allocator = allocator, .n_jobs = options.threads - 1 });
defer pool.deinit();
var out_err: ?anyerror = null;
wg.start();
self.extractThread(alloc, archive, path, options, &wg, &pool, &out_err, null);
pool.waitAndWork(&wg);
if (out_err != null) return out_err.?;
var fil = try std.fs.cwd().openFile(path, .{});
defer fil.close();
const time = @as(i128, self.hdr.mod_time) * 1000000000;
try fil.updateTimes(time, time);
if (options.ignore_permissions) {
try fil.chmod(self.hdr.permissions);
try fil.chown(try archive.id_table.get(self.hdr.uid_idx), try archive.id_table.get(self.hdr.gid_idx));
}
},
.file, .ext_file => {
var pool: Pool = undefined;
try pool.init(.{ .allocator = allocator, .n_jobs = options.threads - 1 });
defer pool.deinit();
var arena_alloc: std.heap.ArenaAllocator = .init(allocator);
defer arena_alloc.deinit();
var thread_alloc: std.heap.ThreadSafeAllocator = .{ .child_allocator = arena_alloc.allocator() };
const alloc = thread_alloc.allocator();
try self.extractRegFileThreaded(alloc, archive, path, options, &pool);
var fil = try std.fs.cwd().openFile(path, .{});
defer fil.close();
const time = @as(i128, self.hdr.mod_time) * 1000000000;
try fil.updateTimes(time, time);
if (!options.ignore_permissions) {
try fil.chmod(self.hdr.permissions);
try fil.chown(try archive.id_table.get(self.hdr.uid_idx), try archive.id_table.get(self.hdr.gid_idx));
}
},
.symlink, .ext_symlink => try self.extractSymlink(path),
else => try self.extractDevice(archive, path, options),
}
}
fn extractThreadEntry(
entry: DirEntry,
alloc: std.mem.Allocator,
archive: *Archive,
path: []const u8,
options: ExtractionOptions,
wg: *WaitGroup,
pool: *Pool,
out_err: *?anyerror,
parent: ?*Parent,
) void {
var new_path = alloc.alloc(u8, path.len + entry.name.len + 1) catch |err| {
wg.finish();
out_err.* = err;
return;
};
@memcpy(new_path[0..path.len], path);
@memcpy(new_path[path.len + 1 ..], entry.name);
new_path[path.len] = '/';
var inode = readFromEntry(alloc, archive, entry) catch |err| {
out_err.* = err;
wg.finish();
return;
};
inode.extractThread(alloc, archive, new_path, options, wg, pool, out_err, parent);
}
/// Extract threadedly the inode to the path.
fn extractThread(
self: Inode,
alloc: std.mem.Allocator,
archive: *Archive,
path: []const u8,
options: ExtractionOptions,
wg: *WaitGroup,
pool: *Pool,
out_err: *?anyerror,
parent: ?*Parent,
) void {
if (options.verbose)
options.verbose_writer.?.print("Extracting inode #{} to {s}\n", .{ self.hdr.num, path }) catch {};
defer {
if (parent != null) parent.?.finish() catch |err| {
if (options.verbose)
options.verbose_writer.?.print("Error setting folder permission to {s}: {}\n", .{ path, err }) catch {};
out_err.* = err;
};
wg.finish();
}
if (out_err.* != null) return;
switch (self.hdr.inode_type) {
.dir, .ext_dir => {
_ = std.fs.cwd().makePathStatus(path) catch |err| {
if (options.verbose)
options.verbose_writer.?.print("Error creating {s}: {}\n", .{ path, err }) catch {};
out_err.* = err;
return;
};
const entries = self.dirEntries(alloc, archive.*) catch |err| {
if (options.verbose)
options.verbose_writer.?.print("Error getting directory entries for inode #{} (extracting to {s}): {}\n", .{ self.hdr.num, path, err }) catch {};
out_err.* = err;
return;
};
const p = Parent.create(alloc, self.hdr, archive, path, options, entries.len) catch |err| {
out_err.* = err;
return;
};
wg.startMany(entries.len);
// defer files.deinit(alloc); We don't need to do this due to ArenaAllocator
for (entries) |entry| {
if (entry.inode_type == .dir) {
extractThreadEntry(entry, alloc, archive, path, options, wg, pool, out_err, p);
continue;
}
pool.spawn(
extractThreadEntry,
.{
entry,
alloc,
archive,
path,
options,
wg,
pool,
out_err,
p,
},
) catch |err| {
wg.finish();
if (options.verbose)
options.verbose_writer.?.print("Error starting extraction thread: {}\n", .{err}) catch {};
out_err.* = err;
continue;
};
}
},
.file, .ext_file => {
self.extractRegFileThreaded(alloc, archive, path, options, pool) catch |err| {
if (options.verbose)
options.verbose_writer.?.print("Error extracting file inode #{} to {s}: {}\n", .{ self.hdr.num, path, err }) catch {};
out_err.* = err;
};
},
.symlink, .ext_symlink => {
self.extractSymlink(path) catch |err| {
if (options.verbose)
options.verbose_writer.?.print("Error extracting symlink inode #{} to {s}: {}\n", .{ self.hdr.num, path, err }) catch {};
out_err.* = err;
};
},
else => {
self.extractDevice(archive, path, options) catch |err| {
if (options.verbose)
options.verbose_writer.?.print("Error extracting device/IPC inode #{} to {s}: {}\n", .{ self.hdr.num, path, err }) catch {};
out_err.* = err;
};
},
}
}
/// Creates and writes the inode file contents to the given path.
/// Optionally set owner & permissions.
///
/// Assumes the inode is a file or ext_file type.
fn extractRegFile(self: Inode, alloc: std.mem.Allocator, archive: *Archive, path: []const u8, options: ExtractionOptions) !void {
var fil = try std.fs.cwd().createFile(path, .{ .exclusive = true });
defer fil.close();
var wrt = fil.writer(&[0]u8{});
var dat_rdr = try self.dataReader(alloc, archive);
defer dat_rdr.deinit();
_ = try dat_rdr.interface.streamRemaining(&wrt.interface);
try wrt.interface.flush();
const time = @as(i128, self.hdr.mod_time) * 1000000000;
try fil.updateTimes(time, time);
if (!options.ignore_permissions) {
try fil.chmod(self.hdr.permissions);
try fil.chown(try archive.id_table.get(self.hdr.uid_idx), try archive.id_table.get(self.hdr.gid_idx));
}
}
/// Extract the inode file contents to the given path threadedly.
/// pool is used to spawn threads.
///
/// Assumes the inode is a file or ext_file type.
fn extractRegFileThreaded(self: Inode, alloc: std.mem.Allocator, archive: *Archive, path: []const u8, options: ExtractionOptions, pool: *Pool) !void {
var fil = try std.fs.cwd().createFile(path, .{});
defer fil.close();
var data = try self.threadedDataReader(alloc, archive);
try data.extractThreaded(fil, pool);
const time = @as(i128, self.hdr.mod_time) * 1000000000;
try fil.updateTimes(time, time);
if (!options.ignore_permissions) {
try fil.chmod(self.hdr.permissions);
try fil.chown(try archive.id_table.get(self.hdr.uid_idx), try archive.id_table.get(self.hdr.gid_idx));
}
}
/// Creates the symlink described by the inode.
///
/// Assumes the inode is a symlink or ext_symlink type.
fn extractSymlink(self: Inode, path: []const u8) !void {
const target = switch (self.data) {
.symlink => |s| s.target,
.ext_symlink => |s| s.target,
else => unreachable,
};
try std.fs.cwd().symLink(target, path, .{});
}
/// Creates the device described by the inode.
///
/// Optionally set owner & permissions.
/// Assumes the inode is a char_dev, block_dev, fifo, socket, or their extended counterparts.
fn extractDevice(self: Inode, archive: *Archive, path: []const u8, options: ExtractionOptions) !void {
var mode: u32 = undefined;
var dev: u32 = 0;
switch (self.data) {
.char_dev => |d| {
mode = std.posix.S.IFCHR;
dev = d.dev;
},
.ext_char_dev => |d| {
mode = std.posix.S.IFCHR;
dev = d.dev;
},
.block_dev => |d| {
mode = std.posix.S.IFBLK;
dev = d.dev;
},
.ext_block_dev => |d| {
mode = std.posix.S.IFBLK;
dev = d.dev;
},
.fifo, .ext_fifo => mode = std.posix.S.IFIFO,
.socket, .ext_socket => mode = std.posix.S.IFSOCK,
else => unreachable,
}
const res: std.os.linux.E = @enumFromInt(std.os.linux.mknod(@ptrCast(path), mode, dev));
switch (res) {
.SUCCESS => {},
.ACCES => return std.fs.Dir.MakeError.AccessDenied,
.DQUOT => return std.fs.Dir.MakeError.DiskQuota,
.EXIST => return std.fs.Dir.MakeError.PathAlreadyExists,
.FAULT, .NOENT => return std.fs.Dir.MakeError.BadPathName,
.LOOP => return std.fs.Dir.MakeError.SymLinkLoop,
.NAMETOOLONG => return std.fs.Dir.MakeError.NameTooLong,
.NOMEM => return std.fs.Dir.MakeError.SystemResources,
.NOSPC => return std.fs.Dir.MakeError.NoSpaceLeft,
.NOTDIR => return std.fs.Dir.MakeError.NotDir,
.PERM => return std.fs.Dir.MakeError.PermissionDenied,
.ROFS => return std.fs.Dir.MakeError.ReadOnlyFileSystem,
else => return blk: {
std.debug.print("unhandled mknod result: {}\n", .{res});
break :blk std.fs.Dir.MakeError.Unexpected;
},
}
var fil = try std.fs.cwd().openFile(path, .{});
defer fil.close();
const time = @as(i128, self.hdr.mod_time) * 1000000000;
try fil.updateTimes(time, time);
if (!options.ignore_permissions) {
try fil.chmod(self.hdr.permissions);
try fil.chown(try archive.id_table.get(self.hdr.uid_idx), try archive.id_table.get(self.hdr.gid_idx));
}
if (!options.ignore_xattr) {
// TODO
}
}