authorgravatar for kubkon@jakubkonka.comJakub Konka <kubkon@jakubkonka.com> 2023-04-19 11:27:34+02:00
committergravatar for kubkon@jakubkonka.comJakub Konka <kubkon@jakubkonka.com> 2023-04-21 22:44:27+02:00
log91bb9302e57c62a1340291b8b207b1638b981bc6
tree8e50187918c9255a02a379ea4b9a6465d5a92c21
parentc6e916d7fe4234c821eeeff19a73b334129c00de

macho: correctly dirty the GOT table after memory realloc

2 files changed, 35 insertions(+), 12 deletions(-)

src/link/MachO.zig+34-11
......@@ -163,6 +163,7 @@ error_flags: File.ErrorFlags = File.ErrorFlags{},
163163
164164segment_table_dirty: bool = false,
165165got_table_count_dirty: bool = false,
166got_table_contents_dirty: bool = false,
166167
167168/// A helper var to indicate if we are at the start of the incremental updates, or
168169/// already somewhere further along the update-and-run chain.
......@@ -758,6 +759,13 @@ pub fn flushModule(self: *MachO, comp: *Compilation, prog_node: *std.Progress.No
758759 try self.writeAtom(atom_index, code.items);
759760 }
760761
762 if (self.got_table_contents_dirty) {
763 for (self.got_table.entries.items, 0..) |entry, i| {
764 if (!self.got_table.lookup.contains(entry)) continue;
765 try self.writeOffsetTableEntry(i);
766 }
767 }
768
761769 if (build_options.enable_logging) {
762770 self.logSymtab();
763771 self.logSections();
......@@ -1242,12 +1250,8 @@ pub fn writeAtom(self: *MachO, atom_index: Atom.Index, code: []u8) !void {
12421250 }
12431251
12441252 if (is_hot_update_compatible) {
1245 if (self.base.child_pid) |pid| blk: {
1246 const task = self.hot_state.mach_task orelse {
1247 log.warn("cannot hot swap: no Mach task acquired for child process with pid {d}", .{pid});
1248 break :blk;
1249 };
1250 self.updateAtomInMemory(task, section.segment_index, sym.n_value, code) catch |err| {
1253 if (self.hot_state.mach_task) |task| {
1254 self.writeToMemory(task, section.segment_index, sym.n_value, code) catch |err| {
12511255 log.warn("cannot hot swap: writing to memory failed: {s}", .{@errorName(err)});
12521256 };
12531257 }
......@@ -1262,7 +1266,7 @@ pub fn writeAtom(self: *MachO, atom_index: Atom.Index, code: []u8) !void {
12621266 }
12631267}
12641268
1265fn updateAtomInMemory(self: *MachO, task: std.os.darwin.MachTask, segment_index: u8, addr: u64, code: []const u8) !void {
1269fn writeToMemory(self: *MachO, task: std.os.darwin.MachTask, segment_index: u8, addr: u64, code: []const u8) !void {
12661270 const segment = self.segments.items[segment_index];
12671271 const cpu_arch = self.base.options.target.cpu.arch;
12681272 const nwritten = if (!segment.isWriteable())
......@@ -1272,7 +1276,7 @@ fn updateAtomInMemory(self: *MachO, task: std.os.darwin.MachTask, segment_index:
12721276 if (nwritten != code.len) return error.InputOutput;
12731277}
12741278
1275fn writeOffsetTableEntry(self: *MachO, index: @TypeOf(self.got_table).Index) !void {
1279fn writeOffsetTableEntry(self: *MachO, index: usize) !void {
12761280 const sect_id = self.got_section_index.?;
12771281
12781282 if (self.got_table_count_dirty) {
......@@ -1282,18 +1286,27 @@ fn writeOffsetTableEntry(self: *MachO, index: @TypeOf(self.got_table).Index) !vo
12821286 }
12831287
12841288 const header = &self.sections.items(.header)[sect_id];
1289 const segment_index = self.sections.items(.segment_index)[sect_id];
1290 const segment = self.getSegment(sect_id);
12851291 const entry = self.got_table.entries.items[index];
12861292 const entry_value = self.getSymbol(entry).n_value;
12871293 const entry_offset = index * @sizeOf(u64);
12881294 const file_offset = header.offset + entry_offset;
1289 const vmaddr = header.addr + entry_offset;
1290 _ = vmaddr;
1295 const vmaddr = segment.vmaddr + entry_offset;
1296 log.warn("writing GOT entry {d}: @{x} => {x}", .{ index, vmaddr, entry_value });
12911297
12921298 var buf: [8]u8 = undefined;
12931299 mem.writeIntLittle(u64, &buf, entry_value);
12941300 try self.base.file.?.pwriteAll(&buf, file_offset);
12951301
12961302 // TODO write in memory
1303 if (is_hot_update_compatible) {
1304 if (self.hot_state.mach_task) |task| {
1305 self.writeToMemory(task, segment_index, vmaddr, &buf) catch |err| {
1306 log.warn("cannot hot swap: writing to memory failed: {s}", .{@errorName(err)});
1307 };
1308 }
1309 }
12971310}
12981311
12991312fn writePtrWidthAtom(self: *MachO, atom_index: Atom.Index) !void {
......@@ -1322,6 +1335,15 @@ fn markRelocsDirtyByAddress(self: *MachO, addr: u64) void {
13221335 reloc.dirty = true;
13231336 }
13241337 }
1338
1339 // Dirty synthetic table sections if necessary
1340 for (&[_]u8{self.got_section_index.?}, &[_]*bool{&self.got_table_contents_dirty}) |sect_id, dirty| {
1341 if (dirty.*) continue;
1342 const segment_index = self.sections.items(.segment_index)[sect_id];
1343 const segment = self.segments.items[segment_index];
1344 if (segment.vmaddr < addr) continue;
1345 dirty.* = true;
1346 }
13251347}
13261348
13271349pub fn allocateSpecialSymbols(self: *MachO) !void {
......@@ -2097,6 +2119,7 @@ fn addGotEntry(self: *MachO, target: SymbolWithLoc) !void {
20972119 const got_index = try self.got_table.allocateEntry(self.base.allocator, target);
20982120 try self.writeOffsetTableEntry(got_index);
20992121 self.markRelocsDirtyByTarget(target);
2122 self.got_table_count_dirty = true;
21002123}
21012124
21022125fn addStubEntry(self: *MachO, target: SymbolWithLoc) !void {
......@@ -3010,7 +3033,7 @@ fn growSection(self: *MachO, sect_id: u8, needed_size: u64) !void {
30103033 const last_atom = self.getAtom(last_atom_index);
30113034 const sym = last_atom.getSymbol(self);
30123035 break :blk (sym.n_value + last_atom.size) - segment.vmaddr;
3013 } else 0;
3036 } else header.size;
30143037
30153038 log.debug("moving {s},{s} from 0x{x} to 0x{x}", .{
30163039 header.segName(),
src/link/table_section.zig+1-1
......@@ -47,7 +47,7 @@ pub fn TableSection(comptime Entry: type) type {
4747 ) !void {
4848 _ = options;
4949 comptime assert(unused_format_string.len == 0);
50 try writer.writeAll("SectionTable:\n");
50 try writer.writeAll("TableSection:\n");
5151 for (self.entries.items, 0..) |entry, i| {
5252 try writer.print(" {d} => {}\n", .{ i, entry });
5353 }