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coff & pdb: improved correctness of our implementation, it is now able to handle stage1's pdb and print its stack traces

master
Sahnvour 2019-07-28 19:03:36 +02:00
parent d08425a0a5
commit 05032c8693
3 changed files with 113 additions and 45 deletions
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42
std/coff.zig
View File

@ -19,6 +19,7 @@ const IMAGE_NT_OPTIONAL_HDR32_MAGIC = 0x10b;
const IMAGE_NT_OPTIONAL_HDR64_MAGIC = 0x20b;
const IMAGE_NUMBEROF_DIRECTORY_ENTRIES = 16;
const IMAGE_DEBUG_TYPE_CODEVIEW = 2;
const DEBUG_DIRECTORY = 6;
pub const CoffError = error{
@ -28,6 +29,7 @@ pub const CoffError = error{
MissingCoffSection,
};
// Official documentation of the format: https://docs.microsoft.com/en-us/windows/win32/debug/pe-format
pub const Coff = struct {
in_file: File,
allocator: *mem.Allocator,
@ -120,6 +122,7 @@ pub const Coff = struct {
pub fn getPdbPath(self: *Coff, buffer: []u8) !usize {
try self.loadSections();
const header = blk: {
if (self.getSection(".buildid")) |section| {
break :blk section.header;
@ -130,14 +133,32 @@ pub const Coff = struct {
}
};
// The linker puts a chunk that contains the .pdb path right after the
// debug_directory.
const debug_dir = &self.pe_header.data_directory[DEBUG_DIRECTORY];
const file_offset = debug_dir.virtual_address - header.virtual_address + header.pointer_to_raw_data;
try self.in_file.seekTo(file_offset + debug_dir.size);
var file_stream = self.in_file.inStream();
const in = &file_stream.stream;
try self.in_file.seekTo(file_offset);
// Find the correct DebugDirectoryEntry, and where its data is stored.
// It can be in any section.
const debug_dir_entry_count = debug_dir.size / @sizeOf(DebugDirectoryEntry);
var i: u32 = 0;
blk: while (i < debug_dir_entry_count) : (i += 1) {
const debug_dir_entry = try in.readStruct(DebugDirectoryEntry);
if (debug_dir_entry.type == IMAGE_DEBUG_TYPE_CODEVIEW) {
for (self.sections.toSlice()) |*section| {
const section_start = section.header.virtual_address;
const section_size = section.header.misc.virtual_size;
const rva = debug_dir_entry.address_of_raw_data;
const offset = rva - section_start;
if (section_start <= rva and offset < section_size and debug_dir_entry.size_of_data <= section_size - offset) {
try self.in_file.seekTo(section.header.pointer_to_raw_data + offset);
break :blk;
}
}
}
}
var cv_signature: [4]u8 = undefined; // CodeView signature
try in.readNoEof(cv_signature[0..]);
@ -149,7 +170,7 @@ pub const Coff = struct {
// Finally read the null-terminated string.
var byte = try in.readByte();
var i: usize = 0;
i = 0;
while (byte != 0 and i < buffer.len) : (i += 1) {
buffer[i] = byte;
byte = try in.readByte();
@ -178,7 +199,7 @@ pub const Coff = struct {
try self.sections.append(Section{
.header = SectionHeader{
.name = name,
.misc = SectionHeader.Misc{ .physical_address = try in.readIntLittle(u32) },
.misc = SectionHeader.Misc{ .virtual_size = try in.readIntLittle(u32) },
.virtual_address = try in.readIntLittle(u32),
.size_of_raw_data = try in.readIntLittle(u32),
.pointer_to_raw_data = try in.readIntLittle(u32),
@ -222,6 +243,17 @@ const OptionalHeader = struct {
data_directory: [IMAGE_NUMBEROF_DIRECTORY_ENTRIES]DataDirectory,
};
const DebugDirectoryEntry = packed struct {
characteristiccs: u32,
time_date_stamp: u32,
major_version: u16,
minor_version: u16,
@"type": u32,
size_of_data: u32,
address_of_raw_data: u32,
pointer_to_raw_data: u32,
};
pub const Section = struct {
header: SectionHeader,
};

13
std/debug.zig
View File

@ -375,7 +375,7 @@ fn printSourceAtAddressWindows(di: *DebugInfo, out_stream: var, relocated_addres
const obj_basename = fs.path.basename(mod.obj_file_name);
var symbol_i: usize = 0;
const symbol_name = while (symbol_i != mod.symbols.len) {
const symbol_name = if (!mod.populated) "???" else while (symbol_i != mod.symbols.len) {
const prefix = @ptrCast(*pdb.RecordPrefix, &mod.symbols[symbol_i]);
if (prefix.RecordLen < 2)
return error.InvalidDebugInfo;
@ -858,8 +858,10 @@ fn openSelfDebugInfoWindows(allocator: *mem.Allocator) !DebugInfo {
const age = try pdb_stream.stream.readIntLittle(u32);
var guid: [16]u8 = undefined;
try pdb_stream.stream.readNoEof(guid[0..]);
if (version != 20000404) // VC70, only value observed by LLVM team
return error.UnknownPDBVersion;
if (!mem.eql(u8, di.coff.guid, guid) or di.coff.age != age)
return error.InvalidDebugInfo;
return error.PDBMismatch;
// We validated the executable and pdb match.
const string_table_index = str_tab_index: {
@ -903,13 +905,18 @@ fn openSelfDebugInfoWindows(allocator: *mem.Allocator) !DebugInfo {
return error.MissingDebugInfo;
};
di.pdb.string_table = di.pdb.getStreamById(string_table_index) orelse return error.InvalidDebugInfo;
di.pdb.string_table = di.pdb.getStreamById(string_table_index) orelse return error.MissingDebugInfo;
di.pdb.dbi = di.pdb.getStream(pdb.StreamType.Dbi) orelse return error.MissingDebugInfo;
const dbi = di.pdb.dbi;
// Dbi Header
const dbi_stream_header = try dbi.stream.readStruct(pdb.DbiStreamHeader);
if (dbi_stream_header.VersionHeader != 19990903) // V70, only value observed by LLVM team
return error.UnknownPDBVersion;
if (dbi_stream_header.Age != age)
return error.UnmatchingPDB;
const mod_info_size = dbi_stream_header.ModInfoSize;
const section_contrib_size = dbi_stream_header.SectionContributionSize;

103
std/pdb.zig
View File

@ -499,45 +499,78 @@ const Msf = struct {
const superblock = try in.readStruct(SuperBlock);
// Sanity checks
if (!mem.eql(u8, superblock.FileMagic, SuperBlock.file_magic))
return error.InvalidDebugInfo;
if (superblock.FreeBlockMapBlock != 1 and superblock.FreeBlockMapBlock != 2)
return error.InvalidDebugInfo;
if (superblock.NumBlocks * superblock.BlockSize != try file.getEndPos())
return error.InvalidDebugInfo;
switch (superblock.BlockSize) {
// llvm only supports 4096 but we can handle any of these values
512, 1024, 2048, 4096 => {},
else => return error.InvalidDebugInfo,
}
if (superblock.NumBlocks * superblock.BlockSize != try file.getEndPos())
return error.InvalidDebugInfo;
const dir_block_count = blockCountFromSize(superblock.NumDirectoryBytes, superblock.BlockSize);
if (dir_block_count > superblock.BlockSize / @sizeOf(u32))
return error.UnhandledBigDirectoryStream; // cf. BlockMapAddr comment.
self.directory = try MsfStream.init(
try file.seekTo(superblock.BlockSize * superblock.BlockMapAddr);
var dir_blocks = try allocator.alloc(u32, dir_block_count);
for (dir_blocks) |*b| {
b.* = try in.readIntLittle(u32);
}
self.directory = MsfStream.init(
superblock.BlockSize,
blockCountFromSize(superblock.NumDirectoryBytes, superblock.BlockSize),
superblock.BlockSize * superblock.BlockMapAddr,
file,
allocator,
dir_blocks,
);
const begin = self.directory.pos;
const stream_count = try self.directory.stream.readIntLittle(u32);
const stream_sizes = try allocator.alloc(u32, stream_count);
for (stream_sizes) |*s| {
defer allocator.free(stream_sizes);
// Microsoft's implementation uses u32(-1) for inexistant streams.
// These streams are not used, but still participate in the file
// and must be taken into account when resolving stream indices.
const Nil = 0xFFFFFFFF;
for (stream_sizes) |*s, i| {
const size = try self.directory.stream.readIntLittle(u32);
s.* = blockCountFromSize(size, superblock.BlockSize);
s.* = if (size == Nil) 0 else blockCountFromSize(size, superblock.BlockSize);
}
self.streams = try allocator.alloc(MsfStream, stream_count);
for (self.streams) |*stream, i| {
stream.* = try MsfStream.init(
superblock.BlockSize,
stream_sizes[i],
// MsfStream.init expects the file to be at the part where it reads [N]u32
try file.getPos(),
file,
allocator,
);
const size = stream_sizes[i];
if (size == 0) {
stream.* = MsfStream{
.blocks = [_]u32{},
};
} else {
var blocks = try allocator.alloc(u32, size);
var j: u32 = 0;
while (j < size) : (j += 1) {
const block_id = try self.directory.stream.readIntLittle(u32);
const n = (block_id % superblock.BlockSize);
// 0 is for SuperBlock, 1 and 2 for FPMs.
if (block_id == 0 or n == 1 or n == 2 or block_id * superblock.BlockSize > try file.getEndPos())
return error.InvalidBlockIndex;
blocks[j] = block_id;
}
stream.* = MsfStream.init(
superblock.BlockSize,
file,
blocks,
);
}
}
const end = self.directory.pos;
if (end - begin != superblock.NumDirectoryBytes)
return error.InvalidStreamDirectory;
}
};
@ -574,7 +607,6 @@ const SuperBlock = packed struct {
NumDirectoryBytes: u32,
Unknown: u32,
/// The index of a block within the MSF file. At this block is an array of
/// ulittle32_t’s listing the blocks that the stream directory resides on.
/// For large MSF files, the stream directory (which describes the block
@ -584,45 +616,41 @@ const SuperBlock = packed struct {
/// and the stream directory itself can be stitched together accordingly.
/// The number of ulittle32_t’s in this array is given by
/// ceil(NumDirectoryBytes / BlockSize).
// Note: microsoft-pdb code actually suggests this is a variable-length
// array. If the indices of blocks occupied by the Stream Directory didn't
// fit in one page, there would be other u32 following it.
// This would mean the Stream Directory is bigger than BlockSize / sizeof(u32)
// blocks. We're not even close to this with a 1GB pdb file, and LLVM didn't
// implement it so we're kind of safe making this assumption for now.
BlockMapAddr: u32,
};
const MsfStream = struct {
in_file: File,
pos: u64,
blocks: []u32,
block_size: u32,
in_file: File = undefined,
pos: u64 = undefined,
blocks: []u32 = undefined,
block_size: u32 = undefined,
/// Implementation of InStream trait for Pdb.MsfStream
stream: Stream,
stream: Stream = undefined,
pub const Error = @typeOf(read).ReturnType.ErrorSet;
pub const Stream = io.InStream(Error);
fn init(block_size: u32, block_count: u32, pos: u64, file: File, allocator: *mem.Allocator) !MsfStream {
var stream = MsfStream{
fn init(block_size: u32, file: File, blocks: []u32) MsfStream {
const stream = MsfStream{
.in_file = file,
.pos = 0,
.blocks = try allocator.alloc(u32, block_count),
.blocks = blocks,
.block_size = block_size,
.stream = Stream{ .readFn = readFn },
};
var file_stream = file.inStream();
const in = &file_stream.stream;
try file.seekTo(pos);
var i: u32 = 0;
while (i < block_count) : (i += 1) {
stream.blocks[i] = try in.readIntLittle(u32);
}
return stream;
}
fn readNullTermString(self: *MsfStream, allocator: *mem.Allocator) ![]u8 {
var list = ArrayList(u8).init(allocator);
defer list.deinit();
while (true) {
const byte = try self.stream.readByte();
if (byte == 0) {
@ -633,6 +661,7 @@ const MsfStream = struct {
}
fn read(self: *MsfStream, buffer: []u8) !usize {
var block_id = @intCast(usize, self.pos / self.block_size);
var block = self.blocks[block_id];
var offset = self.pos % self.block_size;