ghostty/src/crash/minidump/stream_threadlist.zig
2024-09-22 14:06:59 -07:00

118 lines
4.0 KiB
Zig

const std = @import("std");
const assert = std.debug.assert;
const external = @import("external.zig");
const readerpkg = @import("reader.zig");
const Reader = readerpkg.Reader;
const ReadError = readerpkg.ReadError;
const log = std.log.scoped(.minidump_stream);
/// This is the list of threads from the process.
///
/// This is the Reader implementation. You usually do not use this directly.
/// Instead, use Reader(T).ThreadList which will get you the same thing.
///
/// ThreadList is stream type 0x3.
/// StreamReader is the Reader(T).StreamReader type.
pub fn ThreadListReader(comptime R: type) type {
return struct {
const Self = @This();
/// The number of threads in the list.
count: u32,
/// The rva to the first thread in the list.
rva: u32,
/// Source data and endianness so we can read.
source: R.Source,
endian: std.builtin.Endian,
pub fn init(r: *R.StreamReader) !Self {
assert(r.directory.stream_type == 0x3);
try r.seekToPayload();
const reader = r.source.reader();
// Our count is always a u32 in the header.
const count = try reader.readInt(u32, r.endian);
// Determine if we have padding in our header. It is possible
// for there to be padding if the list header was written by
// a 32-bit process but is being read on a 64-bit process.
const padding = padding: {
const maybe_size = @sizeOf(u32) + (@sizeOf(external.Thread) * count);
switch (std.math.order(maybe_size, r.directory.location.data_size)) {
// It should never be larger than what the directory says.
.gt => return ReadError.StreamSizeMismatch,
// If the sizes match exactly we're good.
.eq => break :padding 0,
.lt => {
const padding = r.directory.location.data_size - maybe_size;
if (padding != 4) return ReadError.StreamSizeMismatch;
break :padding padding;
},
}
};
// Rva is the location of the first thread in the list.
const rva = r.directory.location.rva + @as(u32, @sizeOf(u32)) + padding;
return .{
.count = count,
.rva = rva,
.source = r.source,
.endian = r.endian,
};
}
/// Get the thread entry for the given index.
///
/// Index is asserted to be less than count.
pub fn thread(self: *const Self, i: usize) !external.Thread {
assert(i < self.count);
// Seek to the thread
const offset: u32 = @intCast(@sizeOf(external.Thread) * i);
const rva: u32 = self.rva + offset;
try self.source.seekableStream().seekTo(rva);
// Read the thread
return try self.source.reader().readStructEndian(
external.Thread,
self.endian,
);
}
};
}
test "minidump: threadlist" {
const testing = std.testing;
const alloc = testing.allocator;
var fbs = std.io.fixedBufferStream(@embedFile("../testdata/macos.dmp"));
const R = Reader(*@TypeOf(fbs));
const r = try R.init(&fbs);
// Get our thread list stream
const dir = try r.directory(0);
try testing.expectEqual(3, dir.stream_type);
var sr = try r.streamReader(dir);
// Get our rich structure
const v = try R.ThreadList.init(&sr);
log.warn("threadlist count={} rva={}", .{ v.count, v.rva });
try testing.expectEqual(12, v.count);
for (0..v.count) |i| {
const t = try v.thread(i);
log.warn("thread i={} thread={}", .{ i, t });
// Read our stack memory
var stack_reader = try r.locationReader(t.stack.memory);
const bytes = try stack_reader.reader().readAllAlloc(alloc, t.stack.memory.data_size);
defer alloc.free(bytes);
}
}