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std.builtin.panic(uefi): stack allocate panic message

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In the case that the allocator is unavailable (OOM, etc.), we can
possibly still output the panic message - so now we stack allocate the
message and copy it to the exit data for passing to boot services.
This commit is contained in:
Yusuf Bham 2024-02-16 14:08:23 -05:00 committed by Veikka Tuominen
parent c16aeda8a6
commit 22d964fe22
1 changed files with 29 additions and 20 deletions
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49
lib/std/builtin.zig
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@ -799,44 +799,53 @@ pub fn default_panic(msg: []const u8, error_return_trace: ?*StackTrace, ret_addr
.uefi => {
const uefi = std.os.uefi;
const Formatter = struct {
pub fn fmt(exit_msg: []const u8, out: []u16) ![:0]u16 {
var u8_buf: [256]u8 = undefined;
const slice = try std.fmt.bufPrint(&u8_buf, "err: {s}\r\n", .{exit_msg});
// We pass len - 1 because we need to add a null terminator after
const len = try std.unicode.utf8ToUtf16Le(out[0 .. out.len - 1], slice);
out[len] = 0;
return out[0..len :0];
}
};
const ExitData = struct {
pub fn create_exit_data(exit_msg: []const u8, exit_size: *usize) ![*:0]u16 {
pub fn create_exit_data(exit_msg: [:0]u16, exit_size: *usize) ![*:0]u16 {
// Need boot services for pool allocation
if (uefi.system_table.boot_services == null) {
return error.BootServicesUnavailable;
}
// ExitData buffer must be allocated using boot_services.allocatePool
var utf16: []u16 = try uefi.raw_pool_allocator.alloc(u16, 256);
errdefer uefi.raw_pool_allocator.free(utf16);
// ExitData buffer must be allocated using boot_services.allocatePool (spec: page 220)
const exit_data: []u16 = try uefi.raw_pool_allocator.alloc(u16, exit_msg.len + 1);
if (exit_msg.len > 255) {
return error.MessageTooLong;
}
@memcpy(exit_data[0 .. exit_msg.len + 1], exit_msg[0 .. exit_msg.len + 1]);
exit_size.* = exit_msg.len + 1;
var fmt: [256]u8 = undefined;
const slice = try std.fmt.bufPrint(&fmt, "\r\nerr: {s}\r\n", .{exit_msg});
const len = try std.unicode.utf8ToUtf16Le(utf16, slice);
utf16[len] = 0;
exit_size.* = 256;
return @as([*:0]u16, @ptrCast(utf16.ptr));
return @as([*:0]u16, @ptrCast(exit_data.ptr));
}
};
var exit_size: usize = 0;
const exit_data = ExitData.create_exit_data(msg, &exit_size) catch null;
var buf: [256]u16 = undefined;
const utf16 = Formatter.fmt(msg, &buf) catch null;
if (exit_data) |data| {
var exit_size: usize = 0;
const exit_data = if (utf16) |u|
ExitData.create_exit_data(u, &exit_size) catch null
else
null;
if (utf16) |str| {
// Output to both std_err and con_out, as std_err is easier
// to read in stuff like QEMU at times, but, unlike con_out,
// isn't visible on actual hardware if directly booted into
inline for ([_]?*uefi.protocol.SimpleTextOutput{ uefi.system_table.std_err, uefi.system_table.con_out }) |o| {
if (o) |out| {
_ = out.setAttribute(uefi.protocol.SimpleTextOutput.red);
_ = out.outputString(data);
_ = out.outputString(str);
_ = out.setAttribute(uefi.protocol.SimpleTextOutput.white);
}
}