/
Thread.zig
1099 lines (950 loc) · 38 KB
/
Thread.zig
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// SPDX-License-Identifier: MIT
// Copyright (c) 2015-2021 Zig Contributors
// This file is part of [zig](https://ziglang.org/), which is MIT licensed.
// The MIT license requires this copyright notice to be included in all copies
// and substantial portions of the software.
//! This struct represents a kernel thread, and acts as a namespace for concurrency
//! primitives that operate on kernel threads. For concurrency primitives that support
//! both evented I/O and async I/O, see the respective names in the top level std namespace.
const std = @import("std.zig");
const os = std.os;
const assert = std.debug.assert;
const target = std.Target.current;
const Atomic = std.atomic.Atomic;
pub const AutoResetEvent = @import("Thread/AutoResetEvent.zig");
pub const Futex = @import("Thread/Futex.zig");
pub const ResetEvent = @import("Thread/ResetEvent.zig");
pub const StaticResetEvent = @import("Thread/StaticResetEvent.zig");
pub const Mutex = @import("Thread/Mutex.zig");
pub const Semaphore = @import("Thread/Semaphore.zig");
pub const Condition = @import("Thread/Condition.zig");
pub const spinLoopHint = @compileError("deprecated: use std.atomic.spinLoopHint");
pub const use_pthreads = target.os.tag != .windows and std.builtin.link_libc;
const Thread = @This();
const Impl = if (target.os.tag == .windows)
WindowsThreadImpl
else if (use_pthreads)
PosixThreadImpl
else if (target.os.tag == .linux)
LinuxThreadImpl
else
UnsupportedImpl;
impl: Impl,
pub const max_name_len = switch (std.Target.current.os.tag) {
.linux => 15,
.windows => 31,
.macos, .ios, .watchos, .tvos => 63,
.netbsd => 31,
.freebsd => 15,
.openbsd => 31,
else => 0,
};
pub const SetNameError = error{
NameTooLong,
Unsupported,
Unexpected,
} || os.PrctlError || os.WriteError || std.fs.File.OpenError || std.fmt.BufPrintError;
pub fn setName(self: Thread, name: []const u8) SetNameError!void {
if (name.len > max_name_len) return error.NameTooLong;
const name_with_terminator = blk: {
var name_buf: [max_name_len:0]u8 = undefined;
std.mem.copy(u8, &name_buf, name);
name_buf[name.len] = 0;
break :blk name_buf[0..name.len :0];
};
switch (std.Target.current.os.tag) {
.linux => if (use_pthreads) {
const err = std.c.pthread_setname_np(self.getHandle(), name_with_terminator.ptr);
return switch (err) {
0 => {},
os.ERANGE => unreachable,
else => return os.unexpectedErrno(err),
};
} else if (use_pthreads and self.getHandle() == std.c.pthread_self()) {
const err = try os.prctl(.SET_NAME, .{@ptrToInt(name_with_terminator.ptr)});
return switch (err) {
0 => {},
else => return os.unexpectedErrno(err),
};
} else {
var buf: [32]u8 = undefined;
const path = try std.fmt.bufPrint(&buf, "/proc/self/task/{d}/comm", .{self.getHandle()});
const file = try std.fs.cwd().openFile(path, .{ .write = true });
defer file.close();
try file.writer().writeAll(name);
},
.windows => if (std.Target.current.os.isAtLeast(.windows, .win10_rs1)) |res| {
// SetThreadDescription is only available since version 1607, which is 10.0.14393.795
// See https://en.wikipedia.org/wiki/Microsoft_Windows_SDK
if (!res) {
return error.Unsupported;
}
var name_buf_w: [max_name_len:0]u16 = undefined;
const length = try std.unicode.utf8ToUtf16Le(&name_buf_w, name);
name_buf_w[length] = 0;
try os.windows.SetThreadDescription(
self.getHandle(),
@ptrCast(os.windows.LPWSTR, &name_buf_w),
);
} else {
return error.Unsupported;
},
.macos, .ios, .watchos, .tvos => if (use_pthreads) {
// There doesn't seem to be a way to set the name for an arbitrary thread, only the current one.
if (self.getHandle() != std.c.pthread_self()) return error.Unsupported;
const err = std.c.pthread_setname_np(name_with_terminator.ptr);
return switch (err) {
0 => {},
else => return os.unexpectedErrno(err),
};
},
.netbsd => if (use_pthreads) {
const err = std.c.pthread_setname_np(self.getHandle(), name_with_terminator.ptr, null);
return switch (err) {
0 => {},
os.EINVAL => unreachable,
os.ESRCH => unreachable,
os.ENOMEM => unreachable,
else => return os.unexpectedErrno(err),
};
},
.freebsd, .openbsd => if (use_pthreads) {
// Use pthread_set_name_np for FreeBSD because pthread_setname_np is FreeBSD 12.2+ only.
// TODO maybe revisit this if depending on FreeBSD 12.2+ is acceptable because pthread_setname_np can return an error.
std.c.pthread_set_name_np(self.getHandle(), name_with_terminator.ptr);
},
else => return error.Unsupported,
}
}
pub const GetNameError = error{
// For Windows, the name is converted from UTF16 to UTF8
CodepointTooLarge,
Utf8CannotEncodeSurrogateHalf,
DanglingSurrogateHalf,
ExpectedSecondSurrogateHalf,
UnexpectedSecondSurrogateHalf,
Unsupported,
Unexpected,
} || os.PrctlError || os.ReadError || std.fs.File.OpenError || std.fmt.BufPrintError;
pub fn getName(self: Thread, buffer_ptr: *[max_name_len:0]u8) GetNameError!?[]const u8 {
buffer_ptr[max_name_len] = 0;
var buffer = std.mem.span(buffer_ptr);
switch (std.Target.current.os.tag) {
.linux => if (use_pthreads and comptime std.Target.current.abi.isGnu()) {
const err = std.c.pthread_getname_np(self.getHandle(), buffer.ptr, max_name_len + 1);
return switch (err) {
0 => std.mem.sliceTo(buffer, 0),
os.ERANGE => unreachable,
else => return os.unexpectedErrno(err),
};
} else if (use_pthreads and self.getHandle() == std.c.pthread_self()) {
const err = try os.prctl(.GET_NAME, .{@ptrToInt(buffer.ptr)});
return switch (err) {
0 => std.mem.sliceTo(buffer, 0),
else => return os.unexpectedErrno(err),
};
} else if (!use_pthreads) {
var buf: [32]u8 = undefined;
const path = try std.fmt.bufPrint(&buf, "/proc/self/task/{d}/comm", .{self.getHandle()});
const file = try std.fs.cwd().openFile(path, .{});
defer file.close();
const data_len = try file.reader().readAll(buffer_ptr[0 .. max_name_len + 1]);
return if (data_len >= 1) buffer[0 .. data_len - 1] else null;
} else {
// musl doesn't provide pthread_getname_np and there's no way to retrieve the thread id of an arbitrary thread.
return error.Unsupported;
},
.windows => if (std.Target.current.os.isAtLeast(.windows, .win10_rs1)) |res| {
// GetThreadDescription is only available since version 1607, which is 10.0.14393.795
// See https://en.wikipedia.org/wiki/Microsoft_Windows_SDK
if (!res) {
return error.Unsupported;
}
var name_w: os.windows.LPWSTR = undefined;
try os.windows.GetThreadDescription(self.getHandle(), &name_w);
defer os.windows.LocalFree(name_w);
const data_len = try std.unicode.utf16leToUtf8(buffer, std.mem.sliceTo(name_w, 0));
return if (data_len >= 1) buffer[0..data_len] else null;
} else {
return error.Unsupported;
},
.macos, .ios, .watchos, .tvos => if (use_pthreads) {
const err = std.c.pthread_getname_np(self.getHandle(), buffer.ptr, max_name_len + 1);
return switch (err) {
0 => std.mem.sliceTo(buffer, 0),
os.ESRCH => unreachable,
else => return os.unexpectedErrno(err),
};
},
.netbsd => if (use_pthreads) {
const err = std.c.pthread_getname_np(self.getHandle(), buffer.ptr, max_name_len + 1);
return switch (err) {
0 => std.mem.sliceTo(buffer, 0),
os.EINVAL => unreachable,
os.ESRCH => unreachable,
else => return os.unexpectedErrno(err),
};
},
.freebsd, .openbsd => if (use_pthreads) {
// Use pthread_get_name_np for FreeBSD because pthread_getname_np is FreeBSD 12.2+ only.
// TODO maybe revisit this if depending on FreeBSD 12.2+ is acceptable because pthread_getname_np can return an error.
std.c.pthread_get_name_np(self.getHandle(), buffer.ptr, max_name_len + 1);
return std.mem.sliceTo(buffer, 0);
},
else => return error.Unsupported,
}
}
/// Represents a unique ID per thread.
pub const Id = u64;
/// Returns the platform ID of the callers thread.
/// Attempts to use thread locals and avoid syscalls when possible.
pub fn getCurrentId() Id {
return Impl.getCurrentId();
}
pub const CpuCountError = error{
PermissionDenied,
SystemResources,
Unexpected,
};
/// Returns the platforms view on the number of logical CPU cores available.
pub fn getCpuCount() CpuCountError!usize {
return Impl.getCpuCount();
}
/// Configuration options for hints on how to spawn threads.
pub const SpawnConfig = struct {
// TODO compile-time call graph analysis to determine stack upper bound
// https://github.com/ziglang/zig/issues/157
/// Size in bytes of the Thread's stack
stack_size: usize = 16 * 1024 * 1024,
};
pub const SpawnError = error{
/// A system-imposed limit on the number of threads was encountered.
/// There are a number of limits that may trigger this error:
/// * the RLIMIT_NPROC soft resource limit (set via setrlimit(2)),
/// which limits the number of processes and threads for a real
/// user ID, was reached;
/// * the kernel's system-wide limit on the number of processes and
/// threads, /proc/sys/kernel/threads-max, was reached (see
/// proc(5));
/// * the maximum number of PIDs, /proc/sys/kernel/pid_max, was
/// reached (see proc(5)); or
/// * the PID limit (pids.max) imposed by the cgroup "process num‐
/// ber" (PIDs) controller was reached.
ThreadQuotaExceeded,
/// The kernel cannot allocate sufficient memory to allocate a task structure
/// for the child, or to copy those parts of the caller's context that need to
/// be copied.
SystemResources,
/// Not enough userland memory to spawn the thread.
OutOfMemory,
/// `mlockall` is enabled, and the memory needed to spawn the thread
/// would exceed the limit.
LockedMemoryLimitExceeded,
Unexpected,
};
/// Spawns a new thread which executes `function` using `args` and returns a handle the spawned thread.
/// `config` can be used as hints to the platform for now to spawn and execute the `function`.
/// The caller must eventually either call `join()` to wait for the thread to finish and free its resources
/// or call `detach()` to excuse the caller from calling `join()` and have the thread clean up its resources on completion`.
pub fn spawn(config: SpawnConfig, comptime function: anytype, args: anytype) SpawnError!Thread {
if (std.builtin.single_threaded) {
@compileError("Cannot spawn thread when building in single-threaded mode");
}
const impl = try Impl.spawn(config, function, args);
return Thread{ .impl = impl };
}
/// Represents a kernel thread handle.
/// May be an integer or a pointer depending on the platform.
pub const Handle = Impl.ThreadHandle;
/// Retrns the handle of this thread
pub fn getHandle(self: Thread) Handle {
return self.impl.getHandle();
}
/// Release the obligation of the caller to call `join()` and have the thread clean up its own resources on completion.
/// Once called, this consumes the Thread object and invoking any other functions on it is considered undefined behavior.
pub fn detach(self: Thread) void {
return self.impl.detach();
}
/// Waits for the thread to complete, then deallocates any resources created on `spawn()`.
/// Once called, this consumes the Thread object and invoking any other functions on it is considered undefined behavior.
pub fn join(self: Thread) void {
return self.impl.join();
}
/// State to synchronize detachment of spawner thread to spawned thread
const Completion = Atomic(enum(u8) {
running,
detached,
completed,
});
/// Used by the Thread implementations to call the spawned function with the arguments.
fn callFn(comptime f: anytype, args: anytype) switch (Impl) {
WindowsThreadImpl => std.os.windows.DWORD,
LinuxThreadImpl => u8,
PosixThreadImpl => ?*c_void,
else => unreachable,
} {
const default_value = if (Impl == PosixThreadImpl) null else 0;
const bad_fn_ret = "expected return type of startFn to be 'u8', 'noreturn', 'void', or '!void'";
switch (@typeInfo(@typeInfo(@TypeOf(f)).Fn.return_type.?)) {
.NoReturn => {
@call(.{}, f, args);
},
.Void => {
@call(.{}, f, args);
return default_value;
},
.Int => |info| {
if (info.bits != 8) {
@compileError(bad_fn_ret);
}
const status = @call(.{}, f, args);
if (Impl != PosixThreadImpl) {
return status;
}
// pthreads don't support exit status, ignore value
_ = status;
return default_value;
},
.ErrorUnion => |info| {
if (info.payload != void) {
@compileError(bad_fn_ret);
}
@call(.{}, f, args) catch |err| {
std.debug.warn("error: {s}\n", .{@errorName(err)});
if (@errorReturnTrace()) |trace| {
std.debug.dumpStackTrace(trace.*);
}
};
return default_value;
},
else => {
@compileError(bad_fn_ret);
},
}
}
/// We can't compile error in the `Impl` switch statement as its eagerly evaluated.
/// So instead, we compile-error on the methods themselves for platforms which don't support threads.
const UnsupportedImpl = struct {
pub const ThreadHandle = void;
fn getCurrentId() u64 {
return unsupported({});
}
fn getCpuCount() !usize {
return unsupported({});
}
fn spawn(config: SpawnConfig, comptime f: anytype, args: anytype) !Impl {
return unsupported(.{ config, f, args });
}
fn getHandle(self: Impl) ThreadHandle {
return unsupported(self);
}
fn detach(self: Impl) void {
return unsupported(self);
}
fn join(self: Impl) void {
return unsupported(self);
}
fn unsupported(unusued: anytype) noreturn {
@compileLog("Unsupported operating system", target.os.tag);
_ = unusued;
unreachable;
}
};
const WindowsThreadImpl = struct {
const windows = os.windows;
pub const ThreadHandle = windows.HANDLE;
fn getCurrentId() u64 {
return windows.kernel32.GetCurrentThreadId();
}
fn getCpuCount() !usize {
// Faster than calling into GetSystemInfo(), even if amortized.
return windows.peb().NumberOfProcessors;
}
thread: *ThreadCompletion,
const ThreadCompletion = struct {
completion: Completion,
heap_ptr: windows.PVOID,
heap_handle: windows.HANDLE,
thread_handle: windows.HANDLE = undefined,
fn free(self: ThreadCompletion) void {
const status = windows.kernel32.HeapFree(self.heap_handle, 0, self.heap_ptr);
assert(status != 0);
}
};
fn spawn(config: SpawnConfig, comptime f: anytype, args: anytype) !Impl {
const Args = @TypeOf(args);
const Instance = struct {
fn_args: Args,
thread: ThreadCompletion,
fn entryFn(raw_ptr: windows.PVOID) callconv(.C) windows.DWORD {
const self = @ptrCast(*@This(), @alignCast(@alignOf(@This()), raw_ptr));
defer switch (self.thread.completion.swap(.completed, .SeqCst)) {
.running => {},
.completed => unreachable,
.detached => self.thread.free(),
};
return callFn(f, self.fn_args);
}
};
const heap_handle = windows.kernel32.GetProcessHeap() orelse return error.OutOfMemory;
const alloc_bytes = @alignOf(Instance) + @sizeOf(Instance);
const alloc_ptr = windows.kernel32.HeapAlloc(heap_handle, 0, alloc_bytes) orelse return error.OutOfMemory;
errdefer assert(windows.kernel32.HeapFree(heap_handle, 0, alloc_ptr) != 0);
const instance_bytes = @ptrCast([*]u8, alloc_ptr)[0..alloc_bytes];
const instance = std.heap.FixedBufferAllocator.init(instance_bytes).allocator.create(Instance) catch unreachable;
instance.* = .{
.fn_args = args,
.thread = .{
.completion = Completion.init(.running),
.heap_ptr = alloc_ptr,
.heap_handle = heap_handle,
},
};
// Windows appears to only support SYSTEM_INFO.dwAllocationGranularity minimum stack size.
// Going lower makes it default to that specified in the executable (~1mb).
// Its also fine if the limit here is incorrect as stack size is only a hint.
var stack_size = std.math.cast(u32, config.stack_size) catch std.math.maxInt(u32);
stack_size = std.math.max(64 * 1024, stack_size);
instance.thread.thread_handle = windows.kernel32.CreateThread(
null,
stack_size,
Instance.entryFn,
@ptrCast(*c_void, instance),
0,
null,
) orelse {
const errno = windows.kernel32.GetLastError();
return windows.unexpectedError(errno);
};
return Impl{ .thread = &instance.thread };
}
fn getHandle(self: Impl) ThreadHandle {
return self.thread.thread_handle;
}
fn detach(self: Impl) void {
windows.CloseHandle(self.thread.thread_handle);
switch (self.thread.completion.swap(.detached, .SeqCst)) {
.running => {},
.completed => self.thread.free(),
.detached => unreachable,
}
}
fn join(self: Impl) void {
windows.WaitForSingleObjectEx(self.thread.thread_handle, windows.INFINITE, false) catch unreachable;
windows.CloseHandle(self.thread.thread_handle);
assert(self.thread.completion.load(.SeqCst) == .completed);
self.thread.free();
}
};
const PosixThreadImpl = struct {
const c = std.c;
pub const ThreadHandle = c.pthread_t;
fn getCurrentId() Id {
switch (target.os.tag) {
.linux => {
return LinuxThreadImpl.getCurrentId();
},
.macos, .ios, .watchos, .tvos => {
var thread_id: u64 = undefined;
// Pass thread=null to get the current thread ID.
assert(c.pthread_threadid_np(null, &thread_id) == 0);
return thread_id;
},
.dragonfly => {
return @bitCast(u32, c.lwp_gettid());
},
.netbsd => {
return @bitCast(u32, c._lwp_self());
},
.freebsd => {
return @bitCast(u32, c.pthread_getthreadid_np());
},
.openbsd => {
return @bitCast(u32, c.getthrid());
},
.haiku => {
return @bitCast(u32, c.find_thread(null));
},
else => {
return @ptrToInt(c.pthread_self());
},
}
}
fn getCpuCount() !usize {
switch (target.os.tag) {
.linux => {
return LinuxThreadImpl.getCpuCount();
},
.openbsd => {
var count: c_int = undefined;
var count_size: usize = @sizeOf(c_int);
const mib = [_]c_int{ os.CTL_HW, os.HW_NCPUONLINE };
os.sysctl(&mib, &count, &count_size, null, 0) catch |err| switch (err) {
error.NameTooLong, error.UnknownName => unreachable,
else => |e| return e,
};
return @intCast(usize, count);
},
.haiku => {
var count: u32 = undefined;
var system_info: os.system_info = undefined;
_ = os.system.get_system_info(&system_info); // always returns B_OK
count = system_info.cpu_count;
return @intCast(usize, count);
},
else => {
var count: c_int = undefined;
var count_len: usize = @sizeOf(c_int);
const name = if (comptime target.isDarwin()) "hw.logicalcpu" else "hw.ncpu";
os.sysctlbynameZ(name, &count, &count_len, null, 0) catch |err| switch (err) {
error.NameTooLong, error.UnknownName => unreachable,
else => |e| return e,
};
return @intCast(usize, count);
},
}
}
handle: ThreadHandle,
fn spawn(config: SpawnConfig, comptime f: anytype, args: anytype) !Impl {
const Args = @TypeOf(args);
const allocator = std.heap.c_allocator;
const Instance = struct {
fn entryFn(raw_arg: ?*c_void) callconv(.C) ?*c_void {
// @alignCast() below doesn't support zero-sized-types (ZST)
if (@sizeOf(Args) < 1) {
return callFn(f, @as(Args, undefined));
}
const args_ptr = @ptrCast(*Args, @alignCast(@alignOf(Args), raw_arg));
defer allocator.destroy(args_ptr);
return callFn(f, args_ptr.*);
}
};
const args_ptr = try allocator.create(Args);
args_ptr.* = args;
errdefer allocator.destroy(args_ptr);
var attr: c.pthread_attr_t = undefined;
if (c.pthread_attr_init(&attr) != 0) return error.SystemResources;
defer assert(c.pthread_attr_destroy(&attr) == 0);
// Use the same set of parameters used by the libc-less impl.
const stack_size = std.math.max(config.stack_size, 16 * 1024);
assert(c.pthread_attr_setstacksize(&attr, stack_size) == 0);
assert(c.pthread_attr_setguardsize(&attr, std.mem.page_size) == 0);
var handle: c.pthread_t = undefined;
switch (c.pthread_create(
&handle,
&attr,
Instance.entryFn,
if (@sizeOf(Args) > 1) @ptrCast(*c_void, args_ptr) else undefined,
)) {
0 => return Impl{ .handle = handle },
os.EAGAIN => return error.SystemResources,
os.EPERM => unreachable,
os.EINVAL => unreachable,
else => |err| return os.unexpectedErrno(err),
}
}
fn getHandle(self: Impl) ThreadHandle {
return self.handle;
}
fn detach(self: Impl) void {
switch (c.pthread_detach(self.handle)) {
0 => {},
os.EINVAL => unreachable, // thread handle is not joinable
os.ESRCH => unreachable, // thread handle is invalid
else => unreachable,
}
}
fn join(self: Impl) void {
switch (c.pthread_join(self.handle, null)) {
0 => {},
os.EINVAL => unreachable, // thread handle is not joinable (or another thread is already joining in)
os.ESRCH => unreachable, // thread handle is invalid
os.EDEADLK => unreachable, // two threads tried to join each other
else => unreachable,
}
}
};
const LinuxThreadImpl = struct {
const linux = os.linux;
pub const ThreadHandle = i32;
threadlocal var tls_thread_id: ?Id = null;
fn getCurrentId() Id {
return tls_thread_id orelse {
const tid = @bitCast(u32, linux.gettid());
tls_thread_id = tid;
return tid;
};
}
fn getCpuCount() !usize {
const cpu_set = try os.sched_getaffinity(0);
// TODO: should not need this usize cast
return @as(usize, os.CPU_COUNT(cpu_set));
}
thread: *ThreadCompletion,
const ThreadCompletion = struct {
completion: Completion = Completion.init(.running),
child_tid: Atomic(i32) = Atomic(i32).init(1),
parent_tid: i32 = undefined,
mapped: []align(std.mem.page_size) u8,
/// Calls `munmap(mapped.ptr, mapped.len)` then `exit(1)` without touching the stack (which lives in `mapped.ptr`).
/// Ported over from musl libc's pthread detached implementation:
/// https://github.com/ifduyue/musl/search?q=__unmapself
fn freeAndExit(self: *ThreadCompletion) noreturn {
switch (target.cpu.arch) {
.i386 => asm volatile (
\\ movl $91, %%eax
\\ movl %[ptr], %%ebx
\\ movl %[len], %%ecx
\\ int $128
\\ movl $1, %%eax
\\ movl $0, %%ebx
\\ int $128
:
: [ptr] "r" (@ptrToInt(self.mapped.ptr)),
[len] "r" (self.mapped.len)
: "memory"
),
.x86_64 => asm volatile (
\\ movq $11, %%rax
\\ movq %[ptr], %%rbx
\\ movq %[len], %%rcx
\\ syscall
\\ movq $60, %%rax
\\ movq $1, %%rdi
\\ syscall
:
: [ptr] "r" (@ptrToInt(self.mapped.ptr)),
[len] "r" (self.mapped.len)
: "memory"
),
.arm, .armeb, .thumb, .thumbeb => asm volatile (
\\ mov r7, #91
\\ mov r0, %[ptr]
\\ mov r1, %[len]
\\ svc 0
\\ mov r7, #1
\\ mov r0, #0
\\ svc 0
:
: [ptr] "r" (@ptrToInt(self.mapped.ptr)),
[len] "r" (self.mapped.len)
: "memory"
),
.aarch64, .aarch64_be, .aarch64_32 => asm volatile (
\\ mov x8, #215
\\ mov x0, %[ptr]
\\ mov x1, %[len]
\\ svc 0
\\ mov x8, #93
\\ mov x0, #0
\\ svc 0
:
: [ptr] "r" (@ptrToInt(self.mapped.ptr)),
[len] "r" (self.mapped.len)
: "memory"
),
.mips, .mipsel => asm volatile (
\\ move $sp, $25
\\ li $2, 4091
\\ move $4, %[ptr]
\\ move $5, %[len]
\\ syscall
\\ li $2, 4001
\\ li $4, 0
\\ syscall
:
: [ptr] "r" (@ptrToInt(self.mapped.ptr)),
[len] "r" (self.mapped.len)
: "memory"
),
.mips64, .mips64el => asm volatile (
\\ li $2, 4091
\\ move $4, %[ptr]
\\ move $5, %[len]
\\ syscall
\\ li $2, 4001
\\ li $4, 0
\\ syscall
:
: [ptr] "r" (@ptrToInt(self.mapped.ptr)),
[len] "r" (self.mapped.len)
: "memory"
),
.powerpc, .powerpcle, .powerpc64, .powerpc64le => asm volatile (
\\ li 0, 91
\\ mr %[ptr], 3
\\ mr %[len], 4
\\ sc
\\ li 0, 1
\\ li 3, 0
\\ sc
\\ blr
:
: [ptr] "r" (@ptrToInt(self.mapped.ptr)),
[len] "r" (self.mapped.len)
: "memory"
),
.riscv64 => asm volatile (
\\ li a7, 215
\\ mv a0, %[ptr]
\\ mv a1, %[len]
\\ ecall
\\ li a7, 93
\\ mv a0, zero
\\ ecall
:
: [ptr] "r" (@ptrToInt(self.mapped.ptr)),
[len] "r" (self.mapped.len)
: "memory"
),
else => |cpu_arch| @compileError("Unsupported linux arch: " ++ @tagName(cpu_arch)),
}
unreachable;
}
};
fn spawn(config: SpawnConfig, comptime f: anytype, args: anytype) !Impl {
const Args = @TypeOf(args);
const Instance = struct {
fn_args: Args,
thread: ThreadCompletion,
fn entryFn(raw_arg: usize) callconv(.C) u8 {
const self = @intToPtr(*@This(), raw_arg);
defer switch (self.thread.completion.swap(.completed, .SeqCst)) {
.running => {},
.completed => unreachable,
.detached => self.thread.freeAndExit(),
};
return callFn(f, self.fn_args);
}
};
var guard_offset: usize = undefined;
var stack_offset: usize = undefined;
var tls_offset: usize = undefined;
var instance_offset: usize = undefined;
const map_bytes = blk: {
var bytes: usize = std.mem.page_size;
guard_offset = bytes;
bytes += std.math.max(std.mem.page_size, config.stack_size);
bytes = std.mem.alignForward(bytes, std.mem.page_size);
stack_offset = bytes;
bytes = std.mem.alignForward(bytes, linux.tls.tls_image.alloc_align);
tls_offset = bytes;
bytes += linux.tls.tls_image.alloc_size;
bytes = std.mem.alignForward(bytes, @alignOf(Instance));
instance_offset = bytes;
bytes += @sizeOf(Instance);
bytes = std.mem.alignForward(bytes, std.mem.page_size);
break :blk bytes;
};
// map all memory needed without read/write permissions
// to avoid committing the whole region right away
const mapped = os.mmap(
null,
map_bytes,
os.PROT_NONE,
os.MAP_PRIVATE | os.MAP_ANONYMOUS,
-1,
0,
) catch |err| switch (err) {
error.MemoryMappingNotSupported => unreachable,
error.AccessDenied => unreachable,
error.PermissionDenied => unreachable,
else => |e| return e,
};
assert(mapped.len >= map_bytes);
errdefer os.munmap(mapped);
// map everything but the guard page as read/write
os.mprotect(
mapped[guard_offset..],
os.PROT_READ | os.PROT_WRITE,
) catch |err| switch (err) {
error.AccessDenied => unreachable,
else => |e| return e,
};
// Prepare the TLS segment and prepare a user_desc struct when needed on i386
var tls_ptr = os.linux.tls.prepareTLS(mapped[tls_offset..]);
var user_desc: if (target.cpu.arch == .i386) os.linux.user_desc else void = undefined;
if (target.cpu.arch == .i386) {
defer tls_ptr = @ptrToInt(&user_desc);
user_desc = .{
.entry_number = os.linux.tls.tls_image.gdt_entry_number,
.base_addr = tls_ptr,
.limit = 0xfffff,
.seg_32bit = 1,
.contents = 0, // Data
.read_exec_only = 0,
.limit_in_pages = 1,
.seg_not_present = 0,
.useable = 1,
};
}
const instance = @ptrCast(*Instance, @alignCast(@alignOf(Instance), &mapped[instance_offset]));
instance.* = .{
.fn_args = args,
.thread = .{ .mapped = mapped },
};
const flags: u32 = os.CLONE_THREAD | os.CLONE_DETACHED |
os.CLONE_VM | os.CLONE_FS | os.CLONE_FILES |
os.CLONE_PARENT_SETTID | os.CLONE_CHILD_CLEARTID |
os.CLONE_SIGHAND | os.CLONE_SYSVSEM | os.CLONE_SETTLS;
switch (linux.getErrno(linux.clone(
Instance.entryFn,
@ptrToInt(&mapped[stack_offset]),
flags,
@ptrToInt(instance),
&instance.thread.parent_tid,
tls_ptr,
&instance.thread.child_tid.value,
))) {
0 => return Impl{ .thread = &instance.thread },
os.EAGAIN => return error.ThreadQuotaExceeded,
os.EINVAL => unreachable,
os.ENOMEM => return error.SystemResources,
os.ENOSPC => unreachable,
os.EPERM => unreachable,
os.EUSERS => unreachable,
else => |err| return os.unexpectedErrno(err),
}
}
fn getHandle(self: Impl) ThreadHandle {
return self.thread.parent_tid;
}
fn detach(self: Impl) void {
switch (self.thread.completion.swap(.detached, .SeqCst)) {
.running => {},
.completed => self.join(),
.detached => unreachable,
}
}
fn join(self: Impl) void {
defer os.munmap(self.thread.mapped);
var spin: u8 = 10;
while (true) {
const tid = self.thread.child_tid.load(.SeqCst);
if (tid == 0) {
break;
}
if (spin > 0) {
spin -= 1;
std.atomic.spinLoopHint();
continue;
}
switch (linux.getErrno(linux.futex_wait(
&self.thread.child_tid.value,
linux.FUTEX_WAIT,
tid,
null,
))) {
0 => continue,
os.EINTR => continue,
os.EAGAIN => continue,
else => unreachable,
}
}
}
};
fn testThreadName(thread: *Thread) !void {
const testCases = &[_][]const u8{
"mythread",
"b" ** max_name_len,
};
inline for (testCases) |tc| {
try thread.setName(tc);
var name_buffer: [max_name_len:0]u8 = undefined;
const name = try thread.getName(&name_buffer);
if (name) |value| {
try std.testing.expectEqual(tc.len, value.len);
try std.testing.expectEqualStrings(tc, value);
}
}
}
test "setName, getName" {
if (std.builtin.single_threaded) return error.SkipZigTest;
const Context = struct {
start_wait_event: ResetEvent = undefined,
test_done_event: ResetEvent = undefined,
done: std.atomic.Atomic(bool) = std.atomic.Atomic(bool).init(false),
thread: Thread = undefined,
fn init(self: *@This()) !void {
try self.start_wait_event.init();
try self.test_done_event.init();
}