[v1] golang/xenlight: Add libxl_utils support

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

Posted by Nicolas Belouin 4 years, 10 months ago

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

Signed-off-by: Nicolas Belouin <nicolas.belouin@gandi.net>
---
 tools/golang/xenlight/xenlight_utils.go | 61 +++++++++++++++++++++++++
 1 file changed, 61 insertions(+)
 create mode 100644 tools/golang/xenlight/xenlight_utils.go

diff --git a/tools/golang/xenlight/xenlight_utils.go b/tools/golang/xenlight/xenlight_utils.go
new file mode 100644
index 0000000000..ab7a585ec7
--- /dev/null
+++ b/tools/golang/xenlight/xenlight_utils.go
@@ -0,0 +1,61 @@
+/*
+ * 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"
+
+/*
+ * Other flags that may be needed at some point:
+ *  -lnl-route-3 -lnl-3
+ *
+ * To get back to static linking:
+ * #cgo LDFLAGS: -lxenlight -lyajl_s -lxengnttab -lxenstore -lxenguest -lxentoollog -lxenevtchn -lxenctrl -lxenforeignmemory -lxencall -lz -luuid -lutil
+ */
+
+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))
+	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
+}
-- 
2.22.0


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

Posted by Wei Liu 4 years, 10 months ago

CC George

On Wed, Jun 26, 2019 at 12:27:32PM +0200, Nicolas Belouin wrote:
> The Go bindings for libxl miss functions from libxl_utils, lets start
> with the simple libxl_domid_to_name and its counterpart
> libxl_name_to_domid.
> 
> Signed-off-by: Nicolas Belouin <nicolas.belouin@gandi.net>
> ---
>  tools/golang/xenlight/xenlight_utils.go | 61 +++++++++++++++++++++++++
>  1 file changed, 61 insertions(+)
>  create mode 100644 tools/golang/xenlight/xenlight_utils.go
> 
> diff --git a/tools/golang/xenlight/xenlight_utils.go b/tools/golang/xenlight/xenlight_utils.go
> new file mode 100644
> index 0000000000..ab7a585ec7
> --- /dev/null
> +++ b/tools/golang/xenlight/xenlight_utils.go
> @@ -0,0 +1,61 @@
> +/*
> + * 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"
> +
> +/*
> + * Other flags that may be needed at some point:
> + *  -lnl-route-3 -lnl-3
> + *
> + * To get back to static linking:
> + * #cgo LDFLAGS: -lxenlight -lyajl_s -lxengnttab -lxenstore -lxenguest -lxentoollog -lxenevtchn -lxenctrl -lxenforeignmemory -lxencall -lz -luuid -lutil
> + */
> +
> +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))
> +	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
> +}
> -- 
> 2.22.0
> 

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

Posted by George Dunlap 4 years, 10 months ago

Thanks for the patch!  Looks like a good start; just a couple of comments:

On Wed, Jun 26, 2019 at 11:31 AM Nicolas Belouin
<nicolas.belouin@gandi.net> wrote:
>
> The Go bindings for libxl miss functions from libxl_utils, lets start

let's

> with the simple libxl_domid_to_name and its counterpart
> libxl_name_to_domid.
>
> Signed-off-by: Nicolas Belouin <nicolas.belouin@gandi.net>

> +import "C"
> +
> +/*
> + * Other flags that may be needed at some point:
> + *  -lnl-route-3 -lnl-3
> + *
> + * To get back to static linking:
> + * #cgo LDFLAGS: -lxenlight -lyajl_s -lxengnttab -lxenstore -lxenguest -lxentoollog -lxenevtchn -lxenctrl -lxenforeignmemory -lxencall -lz -luuid -lutil
> + */

I think we can drop this comment -- if anyone decides they want to go
back to static linking, or to add those other flags, they can get them
from `xenlight.go`.

> +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))

libxl_domid_to_name() expects the caller to free() the string returned
to it.  Probably best if we `defer C.free()` here.

Everything else looks good, thanks!

 -George

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