windows: correctly generate GetAce syscall

GetAce expects a failretval==0, and we shouldn't call GetLastError on
error.

For golang/go#66850

Change-Id: I812d71b066d56e8285324e70b8b5b5fb42b5ce35
GitHub-Last-Rev: 40cf7508de5e2b26d245ac12cc5057282303fe5a
GitHub-Pull-Request: golang/sys#205
Reviewed-on: https://go-review.googlesource.com/c/sys/+/599295
Reviewed-by: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@google.com>

windows/security_windows.go

diff --git a/windows/security_windows.go b/windows/security_windows.go
index 97651b5..b6e1ab7 100644
--- a/windows/security_windows.go
+++ b/windows/security_windows.go
@@ -1179,7 +1179,7 @@
 //sys	makeSelfRelativeSD(absoluteSD *SECURITY_DESCRIPTOR, selfRelativeSD *SECURITY_DESCRIPTOR, selfRelativeSDSize *uint32) (err error) = advapi32.MakeSelfRelativeSD
 
 //sys	setEntriesInAcl(countExplicitEntries uint32, explicitEntries *EXPLICIT_ACCESS, oldACL *ACL, newACL **ACL) (ret error) = advapi32.SetEntriesInAclW
-//sys	GetAce(acl *ACL, aceIndex uint32, pAce **ACCESS_ALLOWED_ACE) (ret error) = advapi32.GetAce
+//sys	GetAce(acl *ACL, aceIndex uint32, pAce **ACCESS_ALLOWED_ACE) (err error) = advapi32.GetAce
 
 // Control returns the security descriptor control bits.
 func (sd *SECURITY_DESCRIPTOR) Control() (control SECURITY_DESCRIPTOR_CONTROL, revision uint32, err error) {

windows/zsyscall_windows.go

diff --git a/windows/zsyscall_windows.go b/windows/zsyscall_windows.go
index 92e3cf3..9bb979a 100644
--- a/windows/zsyscall_windows.go
+++ b/windows/zsyscall_windows.go
@@ -793,6 +793,14 @@
 	return
 }
 
+func GetAce(acl *ACL, aceIndex uint32, pAce **ACCESS_ALLOWED_ACE) (err error) {
+	r1, _, e1 := syscall.Syscall(procGetAce.Addr(), 3, uintptr(unsafe.Pointer(acl)), uintptr(aceIndex), uintptr(unsafe.Pointer(pAce)))
+	if r1 == 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
 func GetLengthSid(sid *SID) (len uint32) {
 	r0, _, _ := syscall.Syscall(procGetLengthSid.Addr(), 1, uintptr(unsafe.Pointer(sid)), 0, 0)
 	len = uint32(r0)
@@ -1229,14 +1237,6 @@
 	return
 }
 
-func GetAce(acl *ACL, aceIndex uint32, pAce **ACCESS_ALLOWED_ACE) (ret error) {
-	r0, _, _ := syscall.Syscall(procGetAce.Addr(), 3, uintptr(unsafe.Pointer(acl)), uintptr(aceIndex), uintptr(unsafe.Pointer(pAce)))
-	if r0 == 0 {
-		ret = GetLastError()
-	}
-	return
-}
-
 func SetKernelObjectSecurity(handle Handle, securityInformation SECURITY_INFORMATION, securityDescriptor *SECURITY_DESCRIPTOR) (err error) {
 	r1, _, e1 := syscall.Syscall(procSetKernelObjectSecurity.Addr(), 3, uintptr(handle), uintptr(securityInformation), uintptr(unsafe.Pointer(securityDescriptor)))
 	if r1 == 0 {