From 70bceee22b34a08005cd682a65568886c7347ab0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?C=C3=A9dric=20Luthi?= <cedric.luthi@gmail.com>
Date: Tue, 21 Jun 2022 20:07:20 +0200
Subject: [PATCH] windows: add Global{Alloc,Free}

Reference:
https://docs.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-globalalloc
https://docs.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-globalfree
---
 windows/syscall_windows.go  |  2 ++
 windows/types_windows.go    |  9 +++++++++
 windows/zsyscall_windows.go | 20 ++++++++++++++++++++
 3 files changed, 31 insertions(+)

diff --git a/windows/syscall_windows.go b/windows/syscall_windows.go
index 636e5de60..940aa103a 100644
--- a/windows/syscall_windows.go
+++ b/windows/syscall_windows.go
@@ -364,6 +364,8 @@ func NewCallbackCDecl(fn interface{}) uintptr {
 //sys	SetCommTimeouts(handle Handle, timeouts *CommTimeouts) (err error)
 //sys	GetActiveProcessorCount(groupNumber uint16) (ret uint32)
 //sys	GetMaximumProcessorCount(groupNumber uint16) (ret uint32)
+//sys	GlobalFree(hmem Handle) (handle Handle, err error) [failretval!=0]
+//sys	GlobalAlloc(flags uint32, length uint32) (ptr uintptr, err error)
 
 // Volume Management Functions
 //sys	DefineDosDevice(flags uint32, deviceName *uint16, targetPath *uint16) (err error) = DefineDosDeviceW
diff --git a/windows/types_windows.go b/windows/types_windows.go
index e19471c6a..32d248728 100644
--- a/windows/types_windows.go
+++ b/windows/types_windows.go
@@ -3174,3 +3174,12 @@ type ModuleInfo struct {
 }
 
 const ALL_PROCESSOR_GROUPS = 0xFFFF
+
+// Constants for GlobalAlloc flags.
+const (
+	GMEM_FIXED    = 0x0
+	GMEM_MOVEABLE = 0x2
+	GMEM_ZEROINIT = 0x40
+	GHND          = GMEM_MOVEABLE | GMEM_ZEROINIT
+	GPTR          = GMEM_FIXED | GMEM_ZEROINIT
+)
diff --git a/windows/zsyscall_windows.go b/windows/zsyscall_windows.go
index 68f52c1e6..d8dbd684c 100644
--- a/windows/zsyscall_windows.go
+++ b/windows/zsyscall_windows.go
@@ -286,6 +286,8 @@ var (
 	procGetVolumePathNameW                                   = modkernel32.NewProc("GetVolumePathNameW")
 	procGetVolumePathNamesForVolumeNameW                     = modkernel32.NewProc("GetVolumePathNamesForVolumeNameW")
 	procGetWindowsDirectoryW                                 = modkernel32.NewProc("GetWindowsDirectoryW")
+	procGlobalAlloc                                          = modkernel32.NewProc("GlobalAlloc")
+	procGlobalFree                                           = modkernel32.NewProc("GlobalFree")
 	procInitializeProcThreadAttributeList                    = modkernel32.NewProc("InitializeProcThreadAttributeList")
 	procIsWow64Process                                       = modkernel32.NewProc("IsWow64Process")
 	procIsWow64Process2                                      = modkernel32.NewProc("IsWow64Process2")
@@ -2461,6 +2463,24 @@ func getWindowsDirectory(dir *uint16, dirLen uint32) (len uint32, err error) {
 	return
 }
 
+func GlobalAlloc(flags uint32, length uint32) (ptr uintptr, err error) {
+	r0, _, e1 := syscall.Syscall(procGlobalAlloc.Addr(), 2, uintptr(flags), uintptr(length), 0)
+	ptr = uintptr(r0)
+	if ptr == 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+func GlobalFree(hmem Handle) (handle Handle, err error) {
+	r0, _, e1 := syscall.Syscall(procGlobalFree.Addr(), 1, uintptr(hmem), 0, 0)
+	handle = Handle(r0)
+	if handle != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
 func initializeProcThreadAttributeList(attrlist *ProcThreadAttributeList, attrcount uint32, flags uint32, size *uintptr) (err error) {
 	r1, _, e1 := syscall.Syscall6(procInitializeProcThreadAttributeList.Addr(), 4, uintptr(unsafe.Pointer(attrlist)), uintptr(attrcount), uintptr(flags), uintptr(unsafe.Pointer(size)), 0, 0)
 	if r1 == 0 {