zig/lib/std/debug/SelfInfo/Windows.zig

639 lines
25 KiB
Zig

mutex: Io.Mutex,
ntdll_handle: ?if (load_dll_notification_procs) *anyopaque else noreturn,
notification_cookie: ?LDR.DLL_NOTIFICATION.COOKIE,
modules: std.ArrayList(Module),
pub const init: SelfInfo = .{
.mutex = .init,
.ntdll_handle = null,
.notification_cookie = null,
.modules = .empty,
};
pub fn deinit(si: *SelfInfo, io: Io) void {
const gpa = std.debug.getDebugInfoAllocator();
if (si.notification_cookie) |cookie| unregister: {
switch ((si.getNtdllProc(.LdrUnregisterDllNotification) catch break :unregister)(cookie)) {
.SUCCESS => {},
else => |status| windows.unexpectedStatus(status) catch break :unregister,
}
}
if (si.ntdll_handle) |handle| switch (windows.ntdll.LdrUnloadDll(handle)) {
.SUCCESS => {},
else => |status| windows.unexpectedStatus(status) catch {},
};
for (si.modules.items) |*module| module.deinit(gpa, io);
si.modules.deinit(gpa);
}
pub fn getSymbol(si: *SelfInfo, io: Io, address: usize) Error!std.debug.Symbol {
const gpa = std.debug.getDebugInfoAllocator();
try si.mutex.lock(io);
defer si.mutex.unlock(io);
const module = try si.findModule(gpa, address);
const di = try module.getDebugInfo(gpa, io);
return di.getSymbol(gpa, address - @intFromPtr(module.entry.DllBase));
}
pub fn getModuleName(si: *SelfInfo, io: Io, address: usize) Error![]const u8 {
const gpa = std.debug.getDebugInfoAllocator();
try si.mutex.lock(io);
defer si.mutex.unlock(io);
const module = try si.findModule(gpa, address);
return module.name orelse {
const name = try std.unicode.wtf16LeToWtf8Alloc(gpa, module.entry.BaseDllName.slice());
module.name = name;
return name;
};
}
pub fn getModuleSlide(si: *SelfInfo, io: Io, address: usize) Error!usize {
const gpa = std.debug.getDebugInfoAllocator();
try si.mutex.lock(io);
defer si.mutex.unlock(io);
const module = try si.findModule(gpa, address);
return module.base_address;
}
pub const can_unwind: bool = switch (builtin.cpu.arch) {
else => true,
// On x86, `RtlVirtualUnwind` does not exist. We could in theory use `RtlCaptureStackBackTrace`
// instead, but on x86, it turns out that function is just... doing FP unwinding with esp! It's
// hard to find implementation details to confirm that, but the most authoritative source I have
// is an entry in the LLVM mailing list from 2020/08/16 which contains this quote:
//
// > x86 doesn't have what most architectures would consider an "unwinder" in the sense of
// > restoring registers; there is simply a linked list of frames that participate in SEH and
// > that desire to be called for a dynamic unwind operation, so RtlCaptureStackBackTrace
// > assumes that EBP-based frames are in use and walks an EBP-based frame chain on x86 - not
// > all x86 code is written with EBP-based frames so while even though we generally build the
// > OS that way, you might always run the risk of encountering external code that uses EBP as a
// > general purpose register for which such an unwind attempt for a stack trace would fail.
//
// Regardless, it's easy to effectively confirm this hypothesis just by compiling some code with
// `-fomit-frame-pointer -OReleaseFast` and observing that `RtlCaptureStackBackTrace` returns an
// empty trace when it's called in such an application. Note that without `-OReleaseFast` or
// similar, LLVM seems reluctant to ever clobber ebp, so you'll get a trace returned which just
// contains all of the kernel32/ntdll frames but none of your own. Don't be deceived---this is
// just coincidental!
//
// Anyway, the point is, the only stack walking primitive on x86-windows is FP unwinding. We
// *could* ask Microsoft to do that for us with `RtlCaptureStackBackTrace`... but better to just
// use our existing FP unwinder in `std.debug`!
.x86 => false,
};
pub const UnwindContext = struct {
pc: usize,
cur: windows.CONTEXT,
history_table: windows.UNWIND_HISTORY_TABLE,
pub fn init(ctx: *const std.debug.cpu_context.Native) UnwindContext {
return .{
.pc = @returnAddress(),
.cur = switch (builtin.cpu.arch) {
.x86_64 => std.mem.zeroInit(windows.CONTEXT, .{
.Rax = ctx.gprs.get(.rax),
.Rcx = ctx.gprs.get(.rcx),
.Rdx = ctx.gprs.get(.rdx),
.Rbx = ctx.gprs.get(.rbx),
.Rsp = ctx.gprs.get(.rsp),
.Rbp = ctx.gprs.get(.rbp),
.Rsi = ctx.gprs.get(.rsi),
.Rdi = ctx.gprs.get(.rdi),
.R8 = ctx.gprs.get(.r8),
.R9 = ctx.gprs.get(.r9),
.R10 = ctx.gprs.get(.r10),
.R11 = ctx.gprs.get(.r11),
.R12 = ctx.gprs.get(.r12),
.R13 = ctx.gprs.get(.r13),
.R14 = ctx.gprs.get(.r14),
.R15 = ctx.gprs.get(.r15),
.Rip = ctx.gprs.get(.rip),
}),
.aarch64 => .{
.ContextFlags = 0,
.Cpsr = 0,
.DUMMYUNIONNAME = .{ .X = ctx.x },
.Sp = ctx.sp,
.Pc = ctx.pc,
.V = @splat(.{ .B = @splat(0) }),
.Fpcr = 0,
.Fpsr = 0,
.Bcr = @splat(0),
.Bvr = @splat(0),
.Wcr = @splat(0),
.Wvr = @splat(0),
},
.thumb => .{
.ContextFlags = 0,
.R0 = ctx.r[0],
.R1 = ctx.r[1],
.R2 = ctx.r[2],
.R3 = ctx.r[3],
.R4 = ctx.r[4],
.R5 = ctx.r[5],
.R6 = ctx.r[6],
.R7 = ctx.r[7],
.R8 = ctx.r[8],
.R9 = ctx.r[9],
.R10 = ctx.r[10],
.R11 = ctx.r[11],
.R12 = ctx.r[12],
.Sp = ctx.r[13],
.Lr = ctx.r[14],
.Pc = ctx.r[15],
.Cpsr = 0,
.Fpcsr = 0,
.Padding = 0,
.DUMMYUNIONNAME = .{ .S = @splat(0) },
.Bvr = @splat(0),
.Bcr = @splat(0),
.Wvr = @splat(0),
.Wcr = @splat(0),
.Padding2 = @splat(0),
},
else => comptime unreachable,
},
.history_table = std.mem.zeroes(windows.UNWIND_HISTORY_TABLE),
};
}
pub fn deinit(ctx: *UnwindContext) void {
_ = ctx;
}
pub fn getFp(ctx: *UnwindContext) usize {
return ctx.cur.getRegs().bp;
}
};
pub fn unwindFrame(si: *SelfInfo, io: Io, context: *UnwindContext) Error!usize {
_ = si;
_ = io;
const current_regs = context.cur.getRegs();
var image_base: usize = undefined;
if (windows.ntdll.RtlLookupFunctionEntry(current_regs.ip, &image_base, &context.history_table)) |runtime_function| {
var handler_data: ?*anyopaque = null;
var establisher_frame: usize = undefined;
_ = windows.ntdll.RtlVirtualUnwind(
windows.UNW_FLAG_NHANDLER,
image_base,
current_regs.ip,
runtime_function,
&context.cur,
&handler_data,
&establisher_frame,
null,
);
} else {
// leaf function
context.cur.setIp(@as(*const usize, @ptrFromInt(current_regs.sp)).*);
context.cur.setSp(current_regs.sp + @sizeOf(usize));
}
const next_regs = context.cur.getRegs();
const tib = &windows.teb().NtTib;
if (next_regs.sp < @intFromPtr(tib.StackLimit) or next_regs.sp > @intFromPtr(tib.StackBase)) {
context.pc = 0;
return 0;
}
// Like `DwarfUnwindContext.unwindFrame`, adjust our next lookup pc in case the `call` was this
// function's last instruction making `next_regs.ip` one byte past its end.
context.pc = next_regs.ip -| 1;
return next_regs.ip;
}
const Module = struct {
entry: *const LDR.DATA_TABLE_ENTRY,
name: ?[]const u8,
di: ?(Error!DebugInfo),
const DebugInfo = struct {
arena: std.heap.ArenaAllocator.State,
coff_image_base: u64,
mapped_file: ?MappedFile,
dwarf: ?Dwarf,
pdb: ?Pdb,
coff_section_headers: []coff.SectionHeader,
const MappedFile = struct {
file: Io.File,
section_handle: windows.HANDLE,
section_view: []const u8,
fn deinit(mf: *const MappedFile, io: Io) void {
const process_handle = windows.GetCurrentProcess();
switch (windows.ntdll.NtUnmapViewOfSection(
process_handle,
@constCast(mf.section_view.ptr),
)) {
.SUCCESS => {},
else => |status| windows.unexpectedStatus(status) catch {},
}
windows.CloseHandle(mf.section_handle);
mf.file.close(io);
}
};
fn deinit(di: *DebugInfo, gpa: Allocator, io: Io) void {
if (di.dwarf) |*dwarf| dwarf.deinit(gpa);
if (di.pdb) |*pdb| {
pdb.file_reader.file.close(io);
pdb.deinit();
}
if (di.mapped_file) |*mf| mf.deinit(io);
var arena = di.arena.promote(gpa);
arena.deinit();
}
fn getSymbol(di: *DebugInfo, gpa: Allocator, vaddr: usize) Error!std.debug.Symbol {
pdb: {
const pdb = &(di.pdb orelse break :pdb);
var coff_section: *align(1) const coff.SectionHeader = undefined;
const mod_index = for (pdb.sect_contribs) |sect_contrib| {
if (sect_contrib.section > di.coff_section_headers.len) continue;
// Remember that SectionContribEntry.Section is 1-based.
coff_section = &di.coff_section_headers[sect_contrib.section - 1];
const vaddr_start = coff_section.virtual_address + sect_contrib.offset;
const vaddr_end = vaddr_start + sect_contrib.size;
if (vaddr >= vaddr_start and vaddr < vaddr_end) {
break sect_contrib.module_index;
}
} else {
// we have no information to add to the address
break :pdb;
};
const module = pdb.getModule(mod_index) catch |err| switch (err) {
error.InvalidDebugInfo,
error.MissingDebugInfo,
error.OutOfMemory,
=> |e| return e,
error.ReadFailed,
error.EndOfStream,
=> return error.InvalidDebugInfo,
} orelse {
return error.InvalidDebugInfo; // bad module index
};
return .{
.name = pdb.getSymbolName(module, vaddr - coff_section.virtual_address),
.compile_unit_name = fs.path.basename(module.obj_file_name),
.source_location = pdb.getLineNumberInfo(
module,
vaddr - coff_section.virtual_address,
) catch null,
};
}
dwarf: {
const dwarf = &(di.dwarf orelse break :dwarf);
const dwarf_address = vaddr + di.coff_image_base;
return dwarf.getSymbol(gpa, native_endian, dwarf_address) catch |err| switch (err) {
error.MissingDebugInfo => break :dwarf,
error.InvalidDebugInfo,
error.OutOfMemory,
=> |e| return e,
error.ReadFailed,
error.EndOfStream,
error.Overflow,
error.StreamTooLong,
=> return error.InvalidDebugInfo,
};
}
return error.MissingDebugInfo;
}
};
fn deinit(module: *Module, gpa: Allocator, io: Io) void {
if (module.name) |name| gpa.free(name);
if (module.di) |*di_or_err| if (di_or_err.*) |*di| di.deinit(gpa, io) else |_| {};
module.* = undefined;
}
fn getDebugInfo(module: *Module, gpa: Allocator, io: Io) Error!*DebugInfo {
if (module.di == null) module.di = loadDebugInfo(module, gpa, io);
return if (module.di.?) |*di| di else |err| err;
}
fn loadDebugInfo(module: *const Module, gpa: Allocator, io: Io) Error!DebugInfo {
const mapped_ptr: [*]const u8 = @ptrCast(module.entry.DllBase);
const mapped = mapped_ptr[0..module.entry.SizeOfImage];
var coff_obj = coff.Coff.init(mapped, true) catch return error.InvalidDebugInfo;
var arena_instance: std.heap.ArenaAllocator = .init(gpa);
errdefer arena_instance.deinit();
const arena = arena_instance.allocator();
// The string table is not mapped into memory by the loader, so if a section name is in the
// string table then we have to map the full image file from disk. This can happen when
// a binary is produced with -gdwarf, since the section names are longer than 8 bytes.
const mapped_file: ?DebugInfo.MappedFile = mapped: {
if (!coff_obj.strtabRequired()) break :mapped null;
var path_buffer: [4 + windows.PATH_MAX_WIDE]u16 = undefined;
path_buffer[0..4].* = .{ '\\', '?', '?', '\\' }; // openFileAbsoluteW requires the prefix to be present
const path_slice = module.entry.FullDllName.slice();
@memcpy(path_buffer[4..][0..path_slice.len], path_slice);
const coff_file = Io.Threaded.dirOpenFileWtf16(
null,
path_buffer[0 .. 4 + path_slice.len],
.{},
) catch |err| switch (err) {
error.Canceled => |e| return e,
error.Unexpected => |e| return e,
error.FileNotFound => return error.MissingDebugInfo,
error.FileTooBig,
error.IsDir,
error.NotDir,
error.SymLinkLoop,
error.NameTooLong,
error.BadPathName,
=> return error.InvalidDebugInfo,
error.SystemResources,
error.WouldBlock,
error.AccessDenied,
error.PermissionDenied,
error.NoSpaceLeft,
error.DeviceBusy,
error.NoDevice,
error.PathAlreadyExists,
error.PipeBusy,
error.NetworkNotFound,
error.AntivirusInterference,
error.ProcessFdQuotaExceeded,
error.SystemFdQuotaExceeded,
error.FileLocksUnsupported,
error.FileBusy,
=> return error.ReadFailed,
};
errdefer coff_file.close(io);
var section_handle: windows.HANDLE = undefined;
const create_section_rc = windows.ntdll.NtCreateSection(
&section_handle,
.{
.SPECIFIC = .{ .SECTION = .{
.QUERY = true,
.MAP_READ = true,
} },
.STANDARD = .{ .RIGHTS = .REQUIRED },
},
null,
null,
.{ .READONLY = true },
// The documentation states that if no AllocationAttribute is specified,
// then SEC_COMMIT is the default.
// In practice, this isn't the case and specifying 0 will result in INVALID_PARAMETER_6.
.{ .COMMIT = true },
coff_file.handle,
);
if (create_section_rc != .SUCCESS) return error.MissingDebugInfo;
errdefer windows.CloseHandle(section_handle);
var coff_len: usize = 0;
var section_view_ptr: ?[*]const u8 = null;
const process_handle = windows.GetCurrentProcess();
const map_section_rc = windows.ntdll.NtMapViewOfSection(
section_handle,
process_handle,
@ptrCast(&section_view_ptr),
null,
0,
null,
&coff_len,
.Unmap,
.{},
.{ .READONLY = true },
);
if (map_section_rc != .SUCCESS) return error.MissingDebugInfo;
errdefer switch (windows.ntdll.NtUnmapViewOfSection(
process_handle,
@constCast(section_view_ptr.?),
)) {
.SUCCESS => {},
else => |status| windows.unexpectedStatus(status) catch {},
};
const section_view = section_view_ptr.?[0..coff_len];
coff_obj = coff.Coff.init(section_view, false) catch return error.InvalidDebugInfo;
break :mapped .{
.file = coff_file,
.section_handle = section_handle,
.section_view = section_view,
};
};
errdefer if (mapped_file) |*mf| mf.deinit(io);
const coff_image_base = coff_obj.getImageBase();
var opt_dwarf: ?Dwarf = dwarf: {
if (coff_obj.getSectionByName(".debug_info") == null) break :dwarf null;
var sections: Dwarf.SectionArray = undefined;
inline for (@typeInfo(Dwarf.Section.Id).@"enum".fields, 0..) |section, i| {
sections[i] = if (coff_obj.getSectionByName("." ++ section.name)) |section_header| .{
.data = try coff_obj.getSectionDataAlloc(section_header, arena),
.owned = false,
} else null;
}
break :dwarf .{ .sections = sections };
};
errdefer if (opt_dwarf) |*dwarf| dwarf.deinit(gpa);
if (opt_dwarf) |*dwarf| {
dwarf.open(gpa, native_endian) catch |err| switch (err) {
error.Overflow,
error.EndOfStream,
error.StreamTooLong,
error.ReadFailed,
=> return error.InvalidDebugInfo,
error.InvalidDebugInfo,
error.MissingDebugInfo,
error.OutOfMemory,
=> |e| return e,
};
}
var opt_pdb: ?Pdb = pdb: {
const path = coff_obj.getPdbPath() catch {
return error.InvalidDebugInfo;
} orelse {
break :pdb null;
};
const pdb_file_open_result = if (fs.path.isAbsolute(path)) res: {
break :res Io.Dir.cwd().openFile(io, path, .{});
} else res: {
const self_dir = std.process.executableDirPathAlloc(io, gpa) catch |err| switch (err) {
error.OutOfMemory, error.Unexpected => |e| return e,
else => return error.ReadFailed,
};
defer gpa.free(self_dir);
const abs_path = try fs.path.join(gpa, &.{ self_dir, path });
defer gpa.free(abs_path);
break :res Io.Dir.cwd().openFile(io, abs_path, .{});
};
const pdb_file = pdb_file_open_result catch |err| switch (err) {
error.FileNotFound, error.IsDir => break :pdb null,
else => return error.ReadFailed,
};
errdefer pdb_file.close(io);
const pdb_reader = try arena.create(Io.File.Reader);
pdb_reader.* = pdb_file.reader(io, try arena.alloc(u8, 4096));
var pdb = Pdb.init(gpa, pdb_reader) catch |err| switch (err) {
error.OutOfMemory, error.ReadFailed, error.Unexpected => |e| return e,
else => return error.InvalidDebugInfo,
};
errdefer pdb.deinit();
pdb.parseInfoStream() catch |err| switch (err) {
error.UnknownPDBVersion => return error.UnsupportedDebugInfo,
error.EndOfStream => return error.InvalidDebugInfo,
error.InvalidDebugInfo,
error.MissingDebugInfo,
error.OutOfMemory,
error.ReadFailed,
=> |e| return e,
};
pdb.parseDbiStream() catch |err| switch (err) {
error.UnknownPDBVersion => return error.UnsupportedDebugInfo,
error.EndOfStream,
error.EOF,
error.StreamTooLong,
error.WriteFailed,
=> return error.InvalidDebugInfo,
error.InvalidDebugInfo,
error.OutOfMemory,
error.ReadFailed,
=> |e| return e,
};
if (!std.mem.eql(u8, &coff_obj.guid, &pdb.guid) or coff_obj.age != pdb.age)
return error.InvalidDebugInfo;
break :pdb pdb;
};
errdefer if (opt_pdb) |*pdb| {
pdb.file_reader.file.close(io);
pdb.deinit();
};
const coff_section_headers: []coff.SectionHeader = if (opt_pdb != null) csh: {
break :csh try coff_obj.getSectionHeadersAlloc(arena);
} else &.{};
return .{
.arena = arena_instance.state,
.coff_image_base = coff_image_base,
.mapped_file = mapped_file,
.dwarf = opt_dwarf,
.pdb = opt_pdb,
.coff_section_headers = coff_section_headers,
};
}
};
/// Assumes we already hold `si.mutex`.
fn findModule(si: *SelfInfo, gpa: Allocator, address: usize) error{ MissingDebugInfo, OutOfMemory, Unexpected }!*Module {
for (si.modules.items) |*mod| {
const base = @intFromPtr(mod.entry.DllBase);
if (address >= base and address < base + mod.entry.SizeOfImage) return mod;
}
try si.modules.ensureUnusedCapacity(gpa, 1);
var entry: *LDR.DATA_TABLE_ENTRY = undefined;
switch (windows.ntdll.LdrFindEntryForAddress(@ptrFromInt(address), &entry)) {
.SUCCESS => {},
.DLL_NOT_FOUND => return error.MissingDebugInfo,
else => |status| return windows.unexpectedStatus(status),
}
if (si.notification_cookie == null) {
var notification_cookie: LDR.DLL_NOTIFICATION.COOKIE = undefined;
switch ((try si.getNtdllProc(.LdrRegisterDllNotification))(
.{},
&dllNotification,
si,
&notification_cookie,
)) {
.SUCCESS => si.notification_cookie = notification_cookie,
else => |status| return windows.unexpectedStatus(status),
}
}
const mod = si.modules.addOneAssumeCapacity();
mod.* = .{ .entry = entry, .name = null, .di = null };
return mod;
}
inline fn getNtdllProc(
si: *SelfInfo,
comptime proc: std.meta.DeclEnum(windows.ntdll),
) !@TypeOf(&@field(windows.ntdll, @tagName(proc))) {
return if (load_dll_notification_procs)
@ptrCast(try si.loadNtdllProc(@tagName(proc)))
else
&@field(windows.ntdll, @tagName(proc));
}
fn loadNtdllProc(si: *SelfInfo, name: []const u8) Io.UnexpectedError!*anyopaque {
const ntdll_handle = si.ntdll_handle orelse ntdll_handle: {
var ntdll_handle: *anyopaque = undefined;
switch (windows.ntdll.LdrLoadDll(null, null, &.init(
&.{ 'n', 't', 'd', 'l', 'l', '.', 'd', 'l', 'l' },
), &ntdll_handle)) {
.SUCCESS => {},
else => |status| return windows.unexpectedStatus(status),
}
si.ntdll_handle = ntdll_handle;
break :ntdll_handle ntdll_handle;
};
var proc_addr: *anyopaque = undefined;
switch (windows.ntdll.LdrGetProcedureAddress(ntdll_handle, &.init(name), 0, &proc_addr)) {
.SUCCESS => {},
else => |status| return windows.unexpectedStatus(status),
}
return proc_addr;
}
fn dllNotification(
reason: LDR.DLL_NOTIFICATION.REASON,
data: *const LDR.DLL_NOTIFICATION.DATA,
context: ?*anyopaque,
) callconv(.winapi) void {
const si: *SelfInfo = @ptrCast(@alignCast(context));
switch (reason) {
.LOADED => {},
.UNLOADED => {
const io = std.Options.debug_io;
si.mutex.lockUncancelable(io);
defer si.mutex.unlock(io);
for (si.modules.items, 0..) |*mod, mod_index| {
if (mod.entry.DllBase != data.Unloaded.DllBase) continue;
mod.deinit(std.debug.getDebugInfoAllocator(), io);
_ = si.modules.swapRemove(mod_index);
break;
}
},
}
}
const std = @import("std");
const Io = std.Io;
const Allocator = std.mem.Allocator;
const Dwarf = std.debug.Dwarf;
const Pdb = std.debug.Pdb;
const Error = std.debug.SelfInfoError;
const coff = std.coff;
const fs = std.fs;
const windows = std.os.windows;
const LDR = windows.LDR;
const builtin = @import("builtin");
const native_endian = builtin.target.cpu.arch.endian();
const load_dll_notification_procs = builtin.abi == .msvc and switch (builtin.zig_backend) {
.stage2_c => true,
else => switch (builtin.output_mode) {
.Exe => false,
.Lib => switch (builtin.link_mode) {
.static => true,
.dynamic => false,
},
.Obj => true,
},
};
const SelfInfo = @This();