From: George Dunlap <george.dunlap@citrix.com>
Date: Thu, 26 Dec 2019 17:40:33 +0000 (+0000)
Subject: golang/xenlight: Do proper nil / NULL conversions for builtin Bitmap type
X-Git-Tag: archive/raspbian/4.14.0+80-gd101b417b7-1+rpi1^2~63^2~863
X-Git-Url: https://dgit.raspbian.org/%22http:/www.example.com/cgi/%22https://%22%22/%22http:/www.example.com/cgi/%22https:/%22%22?a=commitdiff_plain;h=6ddfe66eb22e72391e838c88869e10c372465ae2;p=xen.git

golang/xenlight: Do proper nil / NULL conversions for builtin Bitmap type

Similar to the autogenerated types, but for `builtin` Bitmap type.

Signed-off-by: George Dunlap <george.dunlap@citrix.com>
Reviewed-by: Nick Rosbrook <rosbrookn@ainfosec.com>
---

diff --git a/tools/golang/xenlight/xenlight.go b/tools/golang/xenlight/xenlight.go
index 24b1e022ff..b1587b964f 100644
--- a/tools/golang/xenlight/xenlight.go
+++ b/tools/golang/xenlight/xenlight.go
@@ -396,15 +396,17 @@ type Bitmap struct {
 }
 
 func (bm *Bitmap) fromC(cbm *C.libxl_bitmap) error {
-	// Alloc a Go slice for the bytes
-	size := int(cbm.size)
-	bm.bitmap = make([]C.uint8_t, size)
+	bm.bitmap = nil
+	if size := int(cbm.size); size > 0 {
+		// Alloc a Go slice for the bytes
+		bm.bitmap = make([]C.uint8_t, size)
 
-	// Make a slice pointing to the C array
-	cs := (*[1 << 30]C.uint8_t)(unsafe.Pointer(cbm._map))[:size:size]
+		// Make a slice pointing to the C array
+		cs := (*[1 << 30]C.uint8_t)(unsafe.Pointer(cbm._map))[:size:size]
 
-	// And copy the C array into the Go array
-	copy(bm.bitmap, cs)
+		// And copy the C array into the Go array
+		copy(bm.bitmap, cs)
+	}
 
 	return nil
 }
@@ -412,10 +414,12 @@ func (bm *Bitmap) fromC(cbm *C.libxl_bitmap) error {
 func (bm *Bitmap) toC(cbm *C.libxl_bitmap) error {
 	size := len(bm.bitmap)
 	cbm.size = C.uint32_t(size)
-	cbm._map = (*C.uint8_t)(C.malloc(C.ulong(cbm.size) * C.sizeof_uint8_t))
-	cs := (*[1 << 31]C.uint8_t)(unsafe.Pointer(cbm._map))[:size:size]
+	if cbm.size > 0 {
+		cbm._map = (*C.uint8_t)(C.malloc(C.ulong(cbm.size) * C.sizeof_uint8_t))
+		cs := (*[1 << 31]C.uint8_t)(unsafe.Pointer(cbm._map))[:size:size]
 
-	copy(cs, bm.bitmap)
+		copy(cs, bm.bitmap)
+	}
 
 	return nil
 }