From 19e00faab6ad547203cd66b19e1281807329cf65 Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Thu, 29 Aug 2019 17:20:26 -0600
Subject: [PATCH] windows: add mutex management functions

Indeed Go has mutexes of its own, but these are considerably
different from the native Windows ones, that can work across processes
and be put in various namespaces. They're an essential part of Windows
systems programming and important for interfacing with various external
interfaces.

Change-Id: I03987800ed1c134442321678c2c7d7aa359ecb36
Reviewed-on: https://go-review.googlesource.com/c/sys/+/192497
Run-TryBot: Jason A. Donenfeld <Jason@zx2c4.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
---
 windows/syscall_windows.go  |  4 +++
 windows/types_windows.go    | 22 ++++++++++++
 windows/zsyscall_windows.go | 67 +++++++++++++++++++++++++++++++++++++
 3 files changed, 93 insertions(+)

diff --git a/windows/syscall_windows.go b/windows/syscall_windows.go
index 33e7d45a..abdefc33 100644
--- a/windows/syscall_windows.go
+++ b/windows/syscall_windows.go
@@ -257,6 +257,10 @@ func NewCallbackCDecl(fn interface{}) uintptr {
 //sys	SetEvent(event Handle) (err error) = kernel32.SetEvent
 //sys	ResetEvent(event Handle) (err error) = kernel32.ResetEvent
 //sys	PulseEvent(event Handle) (err error) = kernel32.PulseEvent
+//sys	CreateMutex(mutexAttrs *SecurityAttributes, initialOwner bool, name *uint16) (handle Handle, err error) = kernel32.CreateMutexW
+//sys	CreateMutexEx(mutexAttrs *SecurityAttributes, name *uint16, flags uint32, desiredAccess uint32) (handle Handle, err error) = kernel32.CreateMutexExW
+//sys	OpenMutex(desiredAccess uint32, inheritHandle bool, name *uint16) (handle Handle, err error) = kernel32.OpenMutexW
+//sys	ReleaseMutex(mutex Handle) (err error) = kernel32.ReleaseMutex
 //sys	SleepEx(milliseconds uint32, alertable bool) (ret uint32) = kernel32.SleepEx
 //sys	CreateJobObject(jobAttr *SecurityAttributes, name *uint16) (handle Handle, err error) = kernel32.CreateJobObjectW
 //sys	AssignProcessToJobObject(job Handle, process Handle) (err error) = kernel32.AssignProcessToJobObject
diff --git a/windows/types_windows.go b/windows/types_windows.go
index 1e3947f0..1ef80cd7 100644
--- a/windows/types_windows.go
+++ b/windows/types_windows.go
@@ -1190,6 +1190,28 @@ const (
 	REG_QWORD = REG_QWORD_LITTLE_ENDIAN
 )
 
+const (
+	EVENT_MODIFY_STATE = 0x0002
+	EVENT_ALL_ACCESS   = STANDARD_RIGHTS_REQUIRED | SYNCHRONIZE | 0x3
+
+	MUTANT_QUERY_STATE = 0x0001
+	MUTANT_ALL_ACCESS  = STANDARD_RIGHTS_REQUIRED | SYNCHRONIZE | MUTANT_QUERY_STATE
+
+	SEMAPHORE_MODIFY_STATE = 0x0002
+	SEMAPHORE_ALL_ACCESS   = STANDARD_RIGHTS_REQUIRED | SYNCHRONIZE | 0x3
+
+	TIMER_QUERY_STATE  = 0x0001
+	TIMER_MODIFY_STATE = 0x0002
+	TIMER_ALL_ACCESS   = STANDARD_RIGHTS_REQUIRED | SYNCHRONIZE | TIMER_QUERY_STATE | TIMER_MODIFY_STATE
+
+	MUTEX_MODIFY_STATE = MUTANT_QUERY_STATE
+	MUTEX_ALL_ACCESS   = MUTANT_ALL_ACCESS
+
+	CREATE_EVENT_MANUAL_RESET  = 0x1
+	CREATE_EVENT_INITIAL_SET   = 0x2
+	CREATE_MUTEX_INITIAL_OWNER = 0x1
+)
+
 type AddrinfoW struct {
 	Flags     int32
 	Family    int32
diff --git a/windows/zsyscall_windows.go b/windows/zsyscall_windows.go
index 1c275cb9..9c448be3 100644
--- a/windows/zsyscall_windows.go
+++ b/windows/zsyscall_windows.go
@@ -197,6 +197,10 @@ var (
 	procSetEvent                           = modkernel32.NewProc("SetEvent")
 	procResetEvent                         = modkernel32.NewProc("ResetEvent")
 	procPulseEvent                         = modkernel32.NewProc("PulseEvent")
+	procCreateMutexW                       = modkernel32.NewProc("CreateMutexW")
+	procCreateMutexExW                     = modkernel32.NewProc("CreateMutexExW")
+	procOpenMutexW                         = modkernel32.NewProc("OpenMutexW")
+	procReleaseMutex                       = modkernel32.NewProc("ReleaseMutex")
 	procSleepEx                            = modkernel32.NewProc("SleepEx")
 	procCreateJobObjectW                   = modkernel32.NewProc("CreateJobObjectW")
 	procAssignProcessToJobObject           = modkernel32.NewProc("AssignProcessToJobObject")
@@ -2109,6 +2113,69 @@ func PulseEvent(event Handle) (err error) {
 	return
 }
 
+func CreateMutex(mutexAttrs *SecurityAttributes, initialOwner bool, name *uint16) (handle Handle, err error) {
+	var _p0 uint32
+	if initialOwner {
+		_p0 = 1
+	} else {
+		_p0 = 0
+	}
+	r0, _, e1 := syscall.Syscall(procCreateMutexW.Addr(), 3, uintptr(unsafe.Pointer(mutexAttrs)), uintptr(_p0), uintptr(unsafe.Pointer(name)))
+	handle = Handle(r0)
+	if handle == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
+func CreateMutexEx(mutexAttrs *SecurityAttributes, name *uint16, flags uint32, desiredAccess uint32) (handle Handle, err error) {
+	r0, _, e1 := syscall.Syscall6(procCreateMutexExW.Addr(), 4, uintptr(unsafe.Pointer(mutexAttrs)), uintptr(unsafe.Pointer(name)), uintptr(flags), uintptr(desiredAccess), 0, 0)
+	handle = Handle(r0)
+	if handle == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
+func OpenMutex(desiredAccess uint32, inheritHandle bool, name *uint16) (handle Handle, err error) {
+	var _p0 uint32
+	if inheritHandle {
+		_p0 = 1
+	} else {
+		_p0 = 0
+	}
+	r0, _, e1 := syscall.Syscall(procOpenMutexW.Addr(), 3, uintptr(desiredAccess), uintptr(_p0), uintptr(unsafe.Pointer(name)))
+	handle = Handle(r0)
+	if handle == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
+func ReleaseMutex(mutex Handle) (err error) {
+	r1, _, e1 := syscall.Syscall(procReleaseMutex.Addr(), 1, uintptr(mutex), 0, 0)
+	if r1 == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
 func SleepEx(milliseconds uint32, alertable bool) (ret uint32) {
 	var _p0 uint32
 	if alertable {