[Xen-devel] [PATCH] golang/xenlight: Add libxl_utils support

[George Dunlap <george.dunlap@xxxxxxxxxx>]

The Go bindings for libxl miss functions from libxl_utils, let's start
with the simple libxl_domid_to_name and its counterpart
libxl_name_to_domid.

NB that C.GoString() will return "" if it's passed a NULL; see
https://github.com/golang/go/issues/32734#issuecomment-506835432

Signed-off-by: Nicolas Belouin <nicolas.belouin@xxxxxxxxx>
Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxx>
---
v3:
 - Wire into build system
 - Add reference to C.GoString() handling NULL to commit message

Nicolas, could you test to see if this actually works for you?

It would be really good also if we could get something that would do
basic unit testing on a live system, and get that running in osstest.

CC: Nicolas Belouin <nicolas.belouin@xxxxxxxxx>
CC: Ian Jackson <ian.jackson@xxxxxxxxxx>
CC: Wei Liu <wl@xxxxxxx>
---
 tools/golang/xenlight/Makefile          |  2 +-
 tools/golang/xenlight/xenlight_utils.go | 55 +++++++++++++++++++++++++
 2 files changed, 56 insertions(+), 1 deletion(-)
 create mode 100644 tools/golang/xenlight/xenlight_utils.go

diff --git a/tools/golang/xenlight/Makefile b/tools/golang/xenlight/Makefile
index 0987305224..65923df59a 100644
--- a/tools/golang/xenlight/Makefile
+++ b/tools/golang/xenlight/Makefile
@@ -8,7 +8,7 @@ GOXL_PKG_DIR = /src/$(XEN_GOCODE_URL)/xenlight/
 GOXL_INSTALL_DIR = $(GOCODE_DIR)$(GOXL_PKG_DIR)
 
 # PKGSOURCES: Files which comprise the distributed source package
-PKGSOURCES = xenlight.go
+PKGSOURCES = xenlight.go xenlight_utils.go
 
 GO ?= go
 
diff --git a/tools/golang/xenlight/xenlight_utils.go 
b/tools/golang/xenlight/xenlight_utils.go
new file mode 100644
index 0000000000..da1636842d
--- /dev/null
+++ b/tools/golang/xenlight/xenlight_utils.go
@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2019 Nicolas Belouin, Gandi SAS
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; If not, see <http://www.gnu.org/licenses/>.
+ */
+package xenlight
+
+/*
+#cgo LDFLAGS: -lxenlight -lyajl -lxentoollog
+#include <stdlib.h>
+#include <libxl_utils.h>
+*/
+import "C"
+
+import (
+       "unsafe"
+)
+
+//char* libxl_domid_to_name(libxl_ctx *ctx, uint32_t domid);
+func (Ctx *Context) DomidToName(id Domid) (name string) {
+       cDomName := C.libxl_domid_to_name(Ctx.ctx, C.uint32_t(id))
+       defer C.free(unsafe.Pointer(cDomName))
+
+       name = C.GoString(cDomName)
+       return
+}
+
+//int libxl_name_to_domid(libxl_ct *ctx, const char *name, uint32_t *domid)
+func (Ctx *Context) NameToDomid(name string) (id Domid, err error) {
+       cname := C.CString(name)
+       defer C.free(unsafe.Pointer(cname))
+
+       var cDomId C.uint32_t
+
+       ret := C.libxl_name_to_domid(Ctx.ctx, cname, &cDomId)
+       if ret != 0 {
+               err = Error(-ret)
+               return
+       }
+
+       id = Domid(cDomId)
+
+       return
+}
-- 
2.20.1


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