std.Io.Threaded: implement futexes for freebsd

This commit is contained in:
Andrew Kelley 2025-10-27 14:34:42 -07:00
parent a87fd37bf5
commit 4e95c2eb1b

View file

@ -5047,7 +5047,7 @@ fn statFromLinux(stx: *const std.os.linux.Statx) Io.File.Stat {
};
}
fn statFromPosix(st: *const std.posix.Stat) Io.File.Stat {
fn statFromPosix(st: *const posix.Stat) Io.File.Stat {
const atime = st.atime();
const mtime = st.mtime();
const ctime = st.ctime();
@ -5056,20 +5056,20 @@ fn statFromPosix(st: *const std.posix.Stat) Io.File.Stat {
.size = @bitCast(st.size),
.mode = st.mode,
.kind = k: {
const m = st.mode & std.posix.S.IFMT;
const m = st.mode & posix.S.IFMT;
switch (m) {
std.posix.S.IFBLK => break :k .block_device,
std.posix.S.IFCHR => break :k .character_device,
std.posix.S.IFDIR => break :k .directory,
std.posix.S.IFIFO => break :k .named_pipe,
std.posix.S.IFLNK => break :k .sym_link,
std.posix.S.IFREG => break :k .file,
std.posix.S.IFSOCK => break :k .unix_domain_socket,
posix.S.IFBLK => break :k .block_device,
posix.S.IFCHR => break :k .character_device,
posix.S.IFDIR => break :k .directory,
posix.S.IFIFO => break :k .named_pipe,
posix.S.IFLNK => break :k .sym_link,
posix.S.IFREG => break :k .file,
posix.S.IFSOCK => break :k .unix_domain_socket,
else => {},
}
if (native_os == .illumos) switch (m) {
std.posix.S.IFDOOR => break :k .door,
std.posix.S.IFPORT => break :k .event_port,
posix.S.IFDOOR => break :k .door,
posix.S.IFPORT => break :k .event_port,
else => {},
};
@ -5101,11 +5101,11 @@ fn statFromWasi(st: *const std.os.wasi.filestat_t) Io.File.Stat {
};
}
fn timestampFromPosix(timespec: *const std.posix.timespec) Io.Timestamp {
fn timestampFromPosix(timespec: *const posix.timespec) Io.Timestamp {
return .{ .nanoseconds = @intCast(@as(i128, timespec.sec) * std.time.ns_per_s + timespec.nsec) };
}
fn timestampToPosix(nanoseconds: i96) std.posix.timespec {
fn timestampToPosix(nanoseconds: i96) posix.timespec {
return .{
.sec = @intCast(@divFloor(nanoseconds, std.time.ns_per_s)),
.nsec = @intCast(@mod(nanoseconds, std.time.ns_per_s)),
@ -5503,44 +5503,7 @@ const darwin_supports_ulock_wait2 = builtin.os.version_range.semver.min.major >=
fn futexWait(t: *Threaded, ptr: *const std.atomic.Value(u32), expect: u32) Io.Cancelable!void {
@branchHint(.cold);
if (native_os == .linux) {
const linux = std.os.linux;
try t.checkCancel();
const rc = linux.futex_4arg(ptr, .{ .cmd = .WAIT, .private = true }, expect, null);
if (is_debug) switch (linux.E.init(rc)) {
.SUCCESS => {}, // notified by `wake()`
.INTR => {}, // gives caller a chance to check cancellation
.AGAIN => {}, // ptr.* != expect
.INVAL => {}, // possibly timeout overflow
.TIMEDOUT => unreachable,
.FAULT => unreachable, // ptr was invalid
else => unreachable,
};
} else if (native_os.isDarwin()) {
const c = std.c;
const flags: c.UL = .{
.op = .COMPARE_AND_WAIT,
.NO_ERRNO = true,
};
try t.checkCancel();
const status = if (darwin_supports_ulock_wait2)
c.__ulock_wait2(flags, ptr, expect, 0, 0)
else
c.__ulock_wait(flags, ptr, expect, 0);
if (status >= 0) return;
if (is_debug) switch (@as(c.E, @enumFromInt(-status))) {
// Wait was interrupted by the OS or other spurious signalling.
.INTR => {},
// Address of the futex was paged out. This is unlikely, but possible in theory, and
// pthread/libdispatch on darwin bother to handle it. In this case we'll return
// without waiting, but the caller should retry anyway.
.FAULT => {},
.TIMEDOUT => unreachable,
else => unreachable,
};
} else if (builtin.cpu.arch.isWasm()) {
if (builtin.cpu.arch.isWasm()) {
comptime assert(builtin.cpu.has(.wasm, .atomics));
try t.checkCancel();
const timeout: i64 = -1;
@ -5562,57 +5525,74 @@ fn futexWait(t: *Threaded, ptr: *const std.atomic.Value(u32), expect: u32) Io.Ca
2 => assert(!is_debug), // timeout
else => assert(!is_debug),
}
} else if (is_windows) {
try t.checkCancel();
switch (windows.ntdll.RtlWaitOnAddress(ptr, &expect, @sizeOf(@TypeOf(expect)), null)) {
.SUCCESS => {},
.CANCELLED => return error.Canceled,
else => recoverableOsBugDetected(),
}
} else {
@compileError("TODO");
} else switch (native_os) {
.linux => {
const linux = std.os.linux;
try t.checkCancel();
const rc = linux.futex_4arg(ptr, .{ .cmd = .WAIT, .private = true }, expect, null);
if (is_debug) switch (linux.E.init(rc)) {
.SUCCESS => {}, // notified by `wake()`
.INTR => {}, // gives caller a chance to check cancellation
.AGAIN => {}, // ptr.* != expect
.INVAL => {}, // possibly timeout overflow
.TIMEDOUT => unreachable,
.FAULT => unreachable, // ptr was invalid
else => unreachable,
};
},
.driverkit, .ios, .macos, .tvos, .visionos, .watchos => {
const c = std.c;
const flags: c.UL = .{
.op = .COMPARE_AND_WAIT,
.NO_ERRNO = true,
};
try t.checkCancel();
const status = if (darwin_supports_ulock_wait2)
c.__ulock_wait2(flags, ptr, expect, 0, 0)
else
c.__ulock_wait(flags, ptr, expect, 0);
if (status >= 0) return;
if (is_debug) switch (@as(c.E, @enumFromInt(-status))) {
.INTR => {}, // spurious wake
// Address of the futex was paged out. This is unlikely, but possible in theory, and
// pthread/libdispatch on darwin bother to handle it. In this case we'll return
// without waiting, but the caller should retry anyway.
.FAULT => {},
.TIMEDOUT => unreachable,
else => unreachable,
};
},
.windows => {
try t.checkCancel();
switch (windows.ntdll.RtlWaitOnAddress(ptr, &expect, @sizeOf(@TypeOf(expect)), null)) {
.SUCCESS => {},
.CANCELLED => return error.Canceled,
else => recoverableOsBugDetected(),
}
},
.freebsd => {
const flags = @intFromEnum(std.c.UMTX_OP.WAIT_UINT_PRIVATE);
try t.checkCancel();
const rc = std.c._umtx_op(@intFromPtr(&ptr.raw), flags, @as(c_ulong, expect), 0, 0);
if (is_debug) switch (posix.errno(rc)) {
.SUCCESS => {},
.FAULT => unreachable, // one of the args points to invalid memory
.INVAL => unreachable, // arguments should be correct
.TIMEDOUT => unreachable, // no timeout provided
.INTR => {}, // spurious wake
else => unreachable,
};
},
else => @compileError("unimplemented: futexWait"),
}
}
pub fn futexWaitUncancelable(ptr: *const std.atomic.Value(u32), expect: u32) void {
@branchHint(.cold);
if (native_os == .linux) {
const linux = std.os.linux;
const rc = linux.futex_4arg(ptr, .{ .cmd = .WAIT, .private = true }, expect, null);
if (is_debug) switch (linux.E.init(rc)) {
.SUCCESS => {}, // notified by `wake()`
.INTR => {}, // gives caller a chance to check cancellation
.AGAIN => {}, // ptr.* != expect
.INVAL => {}, // possibly timeout overflow
.TIMEDOUT => unreachable,
.FAULT => unreachable, // ptr was invalid
else => unreachable,
};
} else if (native_os.isDarwin()) {
const c = std.c;
const flags: c.UL = .{
.op = .COMPARE_AND_WAIT,
.NO_ERRNO = true,
};
const status = if (darwin_supports_ulock_wait2)
c.__ulock_wait2(flags, ptr, expect, 0, 0)
else
c.__ulock_wait(flags, ptr, expect, 0);
if (status >= 0) return;
if (is_debug) switch (@as(c.E, @enumFromInt(-status))) {
// Wait was interrupted by the OS or other spurious signalling.
.INTR => {},
// Address of the futex was paged out. This is unlikely, but possible in theory, and
// pthread/libdispatch on darwin bother to handle it. In this case we'll return
// without waiting, but the caller should retry anyway.
.FAULT => {},
.TIMEDOUT => unreachable,
else => unreachable,
};
} else if (builtin.cpu.arch.isWasm()) {
if (builtin.cpu.arch.isWasm()) {
comptime assert(builtin.cpu.has(.wasm, .atomics));
const timeout: i64 = -1;
const signed_expect: i32 = @bitCast(expect);
@ -5630,16 +5610,66 @@ pub fn futexWaitUncancelable(ptr: *const std.atomic.Value(u32), expect: u32) voi
switch (result) {
0 => {}, // ok
1 => {}, // expected != loaded
2 => assert(!is_debug), // timeout
else => assert(!is_debug),
}
} else if (is_windows) {
switch (windows.ntdll.RtlWaitOnAddress(ptr, &expect, @sizeOf(@TypeOf(expect)), null)) {
.SUCCESS, .CANCELLED => {},
2 => recoverableOsBugDetected(), // timeout
else => recoverableOsBugDetected(),
}
} else {
@compileError("TODO");
} else switch (native_os) {
.linux => {
const linux = std.os.linux;
const rc = linux.futex_4arg(ptr, .{ .cmd = .WAIT, .private = true }, expect, null);
switch (linux.E.init(rc)) {
.SUCCESS => {}, // notified by `wake()`
.INTR => {}, // gives caller a chance to check cancellation
.AGAIN => {}, // ptr.* != expect
.INVAL => {}, // possibly timeout overflow
.TIMEDOUT => recoverableOsBugDetected(),
.FAULT => recoverableOsBugDetected(), // ptr was invalid
else => recoverableOsBugDetected(),
}
},
.driverkit, .ios, .macos, .tvos, .visionos, .watchos => {
const c = std.c;
const flags: c.UL = .{
.op = .COMPARE_AND_WAIT,
.NO_ERRNO = true,
};
const status = if (darwin_supports_ulock_wait2)
c.__ulock_wait2(flags, ptr, expect, 0, 0)
else
c.__ulock_wait(flags, ptr, expect, 0);
if (status >= 0) return;
switch (@as(c.E, @enumFromInt(-status))) {
// Wait was interrupted by the OS or other spurious signalling.
.INTR => {},
// Address of the futex was paged out. This is unlikely, but possible in theory, and
// pthread/libdispatch on darwin bother to handle it. In this case we'll return
// without waiting, but the caller should retry anyway.
.FAULT => {},
.TIMEDOUT => recoverableOsBugDetected(),
else => recoverableOsBugDetected(),
}
},
.windows => {
switch (windows.ntdll.RtlWaitOnAddress(ptr, &expect, @sizeOf(@TypeOf(expect)), null)) {
.SUCCESS, .CANCELLED => {},
else => recoverableOsBugDetected(),
}
},
.freebsd => {
const flags = @intFromEnum(std.c.UMTX_OP.WAIT_UINT_PRIVATE);
const rc = std.c._umtx_op(@intFromPtr(&ptr.raw), flags, @as(c_ulong, expect), 0, 0);
switch (posix.errno(rc)) {
.SUCCESS => {},
.INTR => {}, // spurious wake
.FAULT => recoverableOsBugDetected(), // one of the args points to invalid memory
.INVAL => recoverableOsBugDetected(), // arguments should be correct
.TIMEDOUT => recoverableOsBugDetected(), // no timeout provided
else => recoverableOsBugDetected(),
}
},
else => @compileError("unimplemented: futexWaitUncancelable"),
}
}
@ -5668,38 +5698,7 @@ pub fn futexWaitDurationUncancelable(ptr: *const std.atomic.Value(u32), expect:
pub fn futexWake(ptr: *const std.atomic.Value(u32), max_waiters: u32) void {
@branchHint(.cold);
if (native_os == .linux) {
const linux = std.os.linux;
const rc = linux.futex_3arg(
&ptr.raw,
.{ .cmd = .WAKE, .private = true },
@min(max_waiters, std.math.maxInt(i32)),
);
if (is_debug) switch (linux.E.init(rc)) {
.SUCCESS => {}, // successful wake up
.INVAL => {}, // invalid futex_wait() on ptr done elsewhere
.FAULT => {}, // pointer became invalid while doing the wake
else => unreachable,
};
} else if (native_os.isDarwin()) {
const c = std.c;
const flags: c.UL = .{
.op = .COMPARE_AND_WAIT,
.NO_ERRNO = true,
.WAKE_ALL = max_waiters > 1,
};
while (true) {
const status = c.__ulock_wake(flags, ptr, 0);
if (status >= 0) return;
switch (@as(c.E, @enumFromInt(-status))) {
.INTR, .CANCELED => continue, // spurious wake()
.FAULT => assert(!is_debug), // __ulock_wake doesn't generate EFAULT according to darwin pthread_cond_t
.NOENT => return, // nothing was woken up
.ALREADY => assert(!is_debug), // only for UL.Op.WAKE_THREAD
else => assert(!is_debug),
}
}
} else if (builtin.cpu.arch.isWasm()) {
if (builtin.cpu.arch.isWasm()) {
comptime assert(builtin.cpu.has(.wasm, .atomics));
assert(max_waiters != 0);
const woken_count = asm volatile (
@ -5712,14 +5711,63 @@ pub fn futexWake(ptr: *const std.atomic.Value(u32), max_waiters: u32) void {
[waiters] "r" (max_waiters),
);
_ = woken_count; // can be 0 when linker flag 'shared-memory' is not enabled
} else if (is_windows) {
assert(max_waiters != 0);
switch (max_waiters) {
1 => windows.ntdll.RtlWakeAddressSingle(ptr),
else => windows.ntdll.RtlWakeAddressAll(ptr),
}
} else {
@compileError("TODO");
} else switch (native_os) {
.linux => {
const linux = std.os.linux;
const rc = linux.futex_3arg(
&ptr.raw,
.{ .cmd = .WAKE, .private = true },
@min(max_waiters, std.math.maxInt(i32)),
);
if (is_debug) switch (linux.E.init(rc)) {
.SUCCESS => {}, // successful wake up
.INVAL => {}, // invalid futex_wait() on ptr done elsewhere
.FAULT => {}, // pointer became invalid while doing the wake
else => unreachable, // deadlock due to operating system bug
};
},
.driverkit, .ios, .macos, .tvos, .visionos, .watchos => {
const c = std.c;
const flags: c.UL = .{
.op = .COMPARE_AND_WAIT,
.NO_ERRNO = true,
.WAKE_ALL = max_waiters > 1,
};
while (true) {
const status = c.__ulock_wake(flags, ptr, 0);
if (status >= 0) return;
switch (@as(c.E, @enumFromInt(-status))) {
.INTR, .CANCELED => continue, // spurious wake()
.FAULT => unreachable, // __ulock_wake doesn't generate EFAULT according to darwin pthread_cond_t
.NOENT => return, // nothing was woken up
.ALREADY => unreachable, // only for UL.Op.WAKE_THREAD
else => unreachable, // deadlock due to operating system bug
}
}
},
.windows => {
assert(max_waiters != 0);
switch (max_waiters) {
1 => windows.ntdll.RtlWakeAddressSingle(ptr),
else => windows.ntdll.RtlWakeAddressAll(ptr),
}
},
.freebsd => {
const rc = std.c._umtx_op(
@intFromPtr(&ptr.raw),
@intFromEnum(std.c.UMTX_OP.WAKE_PRIVATE),
@as(c_ulong, max_waiters),
0, // there is no timeout struct
0, // there is no timeout struct pointer
);
switch (posix.errno(rc)) {
.SUCCESS => {},
.FAULT => {}, // it's ok if the ptr doesn't point to valid memory
.INVAL => unreachable, // arguments should be correct
else => unreachable, // deadlock due to operating system bug
}
},
else => @compileError("unimplemented: futexWake"),
}
}