Commit 861ea64009
Changed files (1)
src
link
src/link/MachO.zig
@@ -947,119 +947,6 @@ fn linkWithLLD(self: *MachO, comp: *Compilation) !void {
log.warn("unexpected LLD stderr:\n{s}", .{stderr});
}
}
-
- // At this stage, LLD has done its job. It is time to patch the resultant
- // binaries up!
- const out_file = try directory.handle.openFile(self.base.options.emit.?.sub_path, .{ .write = true });
- try self.parseFromFile(out_file);
-
- if (self.libsystem_cmd_index == null and self.header.?.filetype == macho.MH_EXECUTE) {
- const text_segment = self.load_commands.items[self.text_segment_cmd_index.?].Segment;
- const text_section = text_segment.sections.items[self.text_section_index.?];
- const after_last_cmd_offset = self.header.?.sizeofcmds + @sizeOf(macho.mach_header_64);
- const needed_size = padToIdeal(@sizeOf(macho.linkedit_data_command));
-
- if (needed_size + after_last_cmd_offset > text_section.offset) {
- log.err("Unable to extend padding between the end of load commands and start of __text section.", .{});
- log.err("Re-run the linker with '-headerpad 0x{x}' option if available, or", .{needed_size});
- log.err("fall back to the system linker by exporting 'ZIG_SYSTEM_LINKER_HACK=1'.", .{});
- return error.NotEnoughPadding;
- }
-
- // Calculate next available dylib ordinal.
- const next_ordinal = blk: {
- var ordinal: u32 = 1;
- for (self.load_commands.items) |cmd| {
- switch (cmd) {
- .Dylib => ordinal += 1,
- else => {},
- }
- }
- break :blk ordinal;
- };
-
- // Add load dylib load command
- self.libsystem_cmd_index = @intCast(u16, self.load_commands.items.len);
- const cmdsize = @intCast(u32, mem.alignForwardGeneric(
- u64,
- @sizeOf(macho.dylib_command) + mem.lenZ(LIB_SYSTEM_PATH),
- @sizeOf(u64),
- ));
- // TODO Find a way to work out runtime version from the OS version triple stored in std.Target.
- // In the meantime, we're gonna hardcode to the minimum compatibility version of 0.0.0.
- const min_version = 0x0;
- var dylib_cmd = emptyGenericCommandWithData(macho.dylib_command{
- .cmd = macho.LC_LOAD_DYLIB,
- .cmdsize = cmdsize,
- .dylib = .{
- .name = @sizeOf(macho.dylib_command),
- .timestamp = 2, // not sure why not simply 0; this is reverse engineered from Mach-O files
- .current_version = min_version,
- .compatibility_version = min_version,
- },
- });
- dylib_cmd.data = try self.base.allocator.alloc(u8, cmdsize - dylib_cmd.inner.dylib.name);
- mem.set(u8, dylib_cmd.data, 0);
- mem.copy(u8, dylib_cmd.data, mem.spanZ(LIB_SYSTEM_PATH));
- try self.load_commands.append(self.base.allocator, .{ .Dylib = dylib_cmd });
- self.header_dirty = true;
- self.load_commands_dirty = true;
-
- if (self.symtab_cmd_index == null or self.dysymtab_cmd_index == null) {
- log.err("Incomplete Mach-O binary: no LC_SYMTAB or LC_DYSYMTAB load command found!", .{});
- log.err("Without the symbol table, it is not possible to patch up the binary for cross-compilation.", .{});
- return error.NoSymbolTableFound;
- }
-
- // Patch dyld info
- try self.fixupBindInfo(next_ordinal);
- try self.fixupLazyBindInfo(next_ordinal);
-
- // Write updated load commands and the header
- try self.writeLoadCommands();
- try self.writeHeader();
-
- assert(!self.header_dirty);
- assert(!self.load_commands_dirty);
- }
- if (self.code_signature_cmd_index == null) outer: {
- if (target.cpu.arch != .aarch64) break :outer; // This is currently needed only for aarch64 targets.
- const text_segment = self.load_commands.items[self.text_segment_cmd_index.?].Segment;
- const text_section = text_segment.sections.items[self.text_section_index.?];
- const after_last_cmd_offset = self.header.?.sizeofcmds + @sizeOf(macho.mach_header_64);
- const needed_size = padToIdeal(@sizeOf(macho.linkedit_data_command));
-
- if (needed_size + after_last_cmd_offset > text_section.offset) {
- log.err("Unable to extend padding between the end of load commands and start of __text section.", .{});
- log.err("Re-run the linker with '-headerpad 0x{x}' option if available, or", .{needed_size});
- log.err("fall back to the system linker by exporting 'ZIG_SYSTEM_LINKER_HACK=1'.", .{});
- return error.NotEnoughPadding;
- }
-
- // Add code signature load command
- self.code_signature_cmd_index = @intCast(u16, self.load_commands.items.len);
- try self.load_commands.append(self.base.allocator, .{
- .LinkeditData = .{
- .cmd = macho.LC_CODE_SIGNATURE,
- .cmdsize = @sizeOf(macho.linkedit_data_command),
- .dataoff = 0,
- .datasize = 0,
- },
- });
- self.header_dirty = true;
- self.load_commands_dirty = true;
-
- // Pad out space for code signature
- try self.writeCodeSignaturePadding();
- // Write updated load commands and the header
- try self.writeLoadCommands();
- try self.writeHeader();
- // Generate adhoc code signature
- try self.writeCodeSignature();
-
- assert(!self.header_dirty);
- assert(!self.load_commands_dirty);
- }
}
}
@@ -3375,177 +3262,6 @@ fn writeHeader(self: *MachO) !void {
self.header_dirty = false;
}
-/// Parse MachO contents from existing binary file.
-fn parseFromFile(self: *MachO, file: fs.File) !void {
- self.base.file = file;
- var reader = file.reader();
- const header = try reader.readStruct(macho.mach_header_64);
- try self.load_commands.ensureCapacity(self.base.allocator, header.ncmds);
- var i: u16 = 0;
- while (i < header.ncmds) : (i += 1) {
- const cmd = try LoadCommand.read(self.base.allocator, reader);
- switch (cmd.cmd()) {
- macho.LC_SEGMENT_64 => {
- const x = cmd.Segment;
- if (parseAndCmpName(&x.inner.segname, "__PAGEZERO")) {
- self.pagezero_segment_cmd_index = i;
- } else if (parseAndCmpName(&x.inner.segname, "__LINKEDIT")) {
- self.linkedit_segment_cmd_index = i;
- } else if (parseAndCmpName(&x.inner.segname, "__TEXT")) {
- self.text_segment_cmd_index = i;
- for (x.sections.items) |sect, j| {
- if (parseAndCmpName(§.sectname, "__text")) {
- self.text_section_index = @intCast(u16, j);
- }
- }
- } else if (parseAndCmpName(&x.inner.segname, "__DATA")) {
- self.data_segment_cmd_index = i;
- } else if (parseAndCmpName(&x.inner.segname, "__DATA_CONST")) {
- self.data_const_segment_cmd_index = i;
- }
- },
- macho.LC_DYLD_INFO_ONLY => {
- self.dyld_info_cmd_index = i;
- },
- macho.LC_SYMTAB => {
- self.symtab_cmd_index = i;
- },
- macho.LC_DYSYMTAB => {
- self.dysymtab_cmd_index = i;
- },
- macho.LC_LOAD_DYLINKER => {
- self.dylinker_cmd_index = i;
- },
- macho.LC_VERSION_MIN_MACOSX, macho.LC_VERSION_MIN_IPHONEOS, macho.LC_VERSION_MIN_WATCHOS, macho.LC_VERSION_MIN_TVOS => {
- self.version_min_cmd_index = i;
- },
- macho.LC_SOURCE_VERSION => {
- self.source_version_cmd_index = i;
- },
- macho.LC_UUID => {
- self.uuid_cmd_index = i;
- },
- macho.LC_MAIN => {
- self.main_cmd_index = i;
- },
- macho.LC_LOAD_DYLIB => {
- const x = cmd.Dylib;
- if (parseAndCmpName(x.data, mem.spanZ(LIB_SYSTEM_PATH))) {
- self.libsystem_cmd_index = i;
- }
- },
- macho.LC_FUNCTION_STARTS => {
- self.function_starts_cmd_index = i;
- },
- macho.LC_DATA_IN_CODE => {
- self.data_in_code_cmd_index = i;
- },
- macho.LC_CODE_SIGNATURE => {
- self.code_signature_cmd_index = i;
- },
- else => {
- log.warn("Unknown load command detected: 0x{x}.", .{cmd.cmd()});
- },
- }
- self.load_commands.appendAssumeCapacity(cmd);
- }
- self.header = header;
-}
-
-fn parseAndCmpName(name: []const u8, needle: []const u8) bool {
- const len = mem.indexOfScalar(u8, name, @as(u8, 0)) orelse name.len;
- return mem.eql(u8, name[0..len], needle);
-}
-
-fn parseSymbolTable(self: *MachO) !void {
- const symtab = self.load_commands.items[self.symtab_cmd_index.?].Symtab;
- const dysymtab = self.load_commands.items[self.dysymtab_cmd_index.?].Dysymtab;
-
- var buffer = try self.base.allocator.alloc(macho.nlist_64, symtab.nsyms);
- defer self.base.allocator.free(buffer);
- const nread = try self.base.file.?.preadAll(@ptrCast([*]u8, buffer)[0 .. symtab.nsyms * @sizeOf(macho.nlist_64)], symtab.symoff);
- assert(@divExact(nread, @sizeOf(macho.nlist_64)) == buffer.len);
-
- try self.locals.ensureCapacity(self.base.allocator, dysymtab.nlocalsym);
- try self.globals.ensureCapacity(self.base.allocator, dysymtab.nextdefsym);
- try self.undef_symbols.ensureCapacity(self.base.allocator, dysymtab.nundefsym);
-
- self.locals.appendSliceAssumeCapacity(buffer[dysymtab.ilocalsym .. dysymtab.ilocalsym + dysymtab.nlocalsym]);
- self.globals.appendSliceAssumeCapacity(buffer[dysymtab.iextdefsym .. dysymtab.iextdefsym + dysymtab.nextdefsym]);
- self.undef_symbols.appendSliceAssumeCapacity(buffer[dysymtab.iundefsym .. dysymtab.iundefsym + dysymtab.nundefsym]);
-}
-
-fn parseStringTable(self: *MachO) !void {
- const symtab = self.load_commands.items[self.symtab_cmd_index.?].Symtab;
-
- var buffer = try self.base.allocator.alloc(u8, symtab.strsize);
- defer self.base.allocator.free(buffer);
- const nread = try self.base.file.?.preadAll(buffer, symtab.stroff);
- assert(nread == buffer.len);
-
- try self.string_table.ensureCapacity(self.base.allocator, symtab.strsize);
- self.string_table.appendSliceAssumeCapacity(buffer);
-}
-
-fn fixupBindInfo(self: *MachO, dylib_ordinal: u32) !void {
- const dyld_info = self.load_commands.items[self.dyld_info_cmd_index.?].DyldInfoOnly;
- var buffer = try self.base.allocator.alloc(u8, dyld_info.bind_size);
- defer self.base.allocator.free(buffer);
- const nread = try self.base.file.?.preadAll(buffer, dyld_info.bind_off);
- assert(nread == buffer.len);
- try self.fixupInfoCommon(buffer, dylib_ordinal);
- try self.base.file.?.pwriteAll(buffer, dyld_info.bind_off);
-}
-
-fn fixupLazyBindInfo(self: *MachO, dylib_ordinal: u32) !void {
- const dyld_info = self.load_commands.items[self.dyld_info_cmd_index.?].DyldInfoOnly;
- var buffer = try self.base.allocator.alloc(u8, dyld_info.lazy_bind_size);
- defer self.base.allocator.free(buffer);
- const nread = try self.base.file.?.preadAll(buffer, dyld_info.lazy_bind_off);
- assert(nread == buffer.len);
- try self.fixupInfoCommon(buffer, dylib_ordinal);
- try self.base.file.?.pwriteAll(buffer, dyld_info.lazy_bind_off);
-}
-
-fn fixupInfoCommon(self: *MachO, buffer: []u8, dylib_ordinal: u32) !void {
- var stream = std.io.fixedBufferStream(buffer);
- var reader = stream.reader();
-
- while (true) {
- const inst = reader.readByte() catch |err| switch (err) {
- error.EndOfStream => break,
- else => return err,
- };
- const imm: u8 = inst & macho.BIND_IMMEDIATE_MASK;
- const opcode: u8 = inst & macho.BIND_OPCODE_MASK;
-
- switch (opcode) {
- macho.BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM => {
- var next = try reader.readByte();
- while (next != @as(u8, 0)) {
- next = try reader.readByte();
- }
- },
- macho.BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB => {
- _ = try std.leb.readULEB128(u64, reader);
- },
- macho.BIND_OPCODE_SET_DYLIB_SPECIAL_IMM, macho.BIND_OPCODE_SET_DYLIB_ORDINAL_IMM => {
- // Perform the fixup.
- try stream.seekBy(-1);
- var writer = stream.writer();
- try writer.writeByte(macho.BIND_OPCODE_SET_DYLIB_ORDINAL_IMM | @truncate(u4, dylib_ordinal));
- },
- macho.BIND_OPCODE_SET_DYLIB_ORDINAL_ULEB => {
- _ = try std.leb.readULEB128(u64, reader);
- },
- macho.BIND_OPCODE_SET_ADDEND_SLEB => {
- _ = try std.leb.readILEB128(i64, reader);
- },
- else => {},
- }
- }
-}
-
pub fn padToIdeal(actual_size: anytype) @TypeOf(actual_size) {
// TODO https://github.com/ziglang/zig/issues/1284
return std.math.add(@TypeOf(actual_size), actual_size, actual_size / ideal_factor) catch