[RFC,59/59] tools/xenlight: Create interface for xenlight info

Commit Message

George Dunlap Dec. 29, 2016, 8:20 p.m. UTC

On Thu, Dec 29, 2016 at 1:45 PM, George Dunlap <[e-mail]> wrote:
> At a high level: I think I began by saying that this would probably all
> be a single patch.  But I think it would probably be easier to review
> the different decisions made at each point by filling out the file bit
> by bit, and explaining what's going on at each point.

[snip]

> I'll take a stab at breaking it down in an example order that makes some
> sense to me, and then you can see what you think.

Here's one way you might break down this series that would make it
easier to review.

I've re-ordered the file somewhat, and there's a slight bug in the
build process so I can't compile it; and many of the descriptions need
to be expanded.  But it should give you the idea of what I'm talking
about.

 -George
From c96a7c71c69c440fd87e77b5e11f7ecdf3263e83 Mon Sep 17 00:00:00 2001
From: George Dunlap <[e-mail]>
Date: Thu, 29 Dec 2016 19:22:41 +0000
Subject: [PATCH 1/7] tools/xenlight: Create stub package

Create a basic Makefile to build and install libxenlight Golang
bindings.  Also add a stub package which only opens libxl context.

Include a global xenlight.Ctx variable which can be used as the
default context by the entire program if desired.

For now, return simple errors.  Proper error handling will be added in
the next patch.

Signed-off-by: Ronald Rojas <[e-mail]>
---
 tools/Makefile                    | 16 ++++++++
 tools/golang/Makefile             | 29 ++++++++++++++
 tools/golang/xenlight/xenlight.go | 80 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 125 insertions(+)
 create mode 100644 tools/golang/Makefile
 create mode 100644 tools/golang/xenlight/xenlight.go

Patch

diff --git a/tools/Makefile b/tools/Makefile
index 77e0723..4c34421 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -12,6 +12,8 @@  SUBDIRS-y += misc
 SUBDIRS-y += examples
 SUBDIRS-y += hotplug
 SUBDIRS-y += xentrace
+SUBDIRS-y += golang
+#FIXME: Have golang controlled by a configure variable
 SUBDIRS-$(CONFIG_XCUTILS) += xcutils
 SUBDIRS-$(CONFIG_X86) += firmware
 SUBDIRS-y += console
@@ -312,6 +314,20 @@  subdir-install-debugger/gdbsx: .phony
 subdir-all-debugger/gdbsx: .phony
 	$(MAKE) -C debugger/gdbsx all
 
+subdir-all-golang/xenlight: .phony
+	$(MAKE) -C golang all
+
+subdir-clean-golang/xenlight: .phony
+	$(MAKE) -C golang clean
+
+subdir-install-golang/xenlight: .phony
+	$(MAKE) -C golang install
+
+subdir-build-golang/xenlight: .phony
+	$(MAKE) -C golang build
+
+subdir-distclean-golang/xenlight: .phony
+	$(MAKE) -C golang distclean
 
 subdir-clean-debugger/kdd subdir-distclean-debugger/kdd: .phony
 	$(MAKE) -C debugger/kdd clean
diff --git a/tools/golang/Makefile b/tools/golang/Makefile
new file mode 100644
index 0000000..96589c8
--- /dev/null
+++ b/tools/golang/Makefile
@@ -0,0 +1,29 @@ 
+XEN_ROOT=$(CURDIR)/../..
+GOLANG_SRC=$(GOPATH)/src/xenproject.org/xenlight
+include $(XEN_ROOT)/tools/Rules.mk
+
+BINARY = xenlight.a
+GO ?= go
+
+.PHONY: all
+all: build
+
+.PHONY: build
+build: xenlight/xenlight.a
+
+.PHONY: install
+install: build
+	$(INSTALL_DIR) $(DESTDIR)$(GOLANG_SRC)
+	$(INSTALL_DATA) xenlight/xenlight.go $(DESTDIR)$(GOLANG_SRC)
+
+.PHONY: clean
+clean:
+	$(RM) xenlight/$(BINARY)
+
+.PHONY: distclean
+distclean: clean
+
+xenlight/xenlight.a: xenlight/xenlight.go
+	$(GO) build -o $@ $<
+
+-include $(DEPS)
diff --git a/tools/golang/xenlight/xenlight.go b/tools/golang/xenlight/xenlight.go
new file mode 100644
index 0000000..b162abb
--- /dev/null
+++ b/tools/golang/xenlight/xenlight.go
@@ -0,0 +1,80 @@ 
+/*
+ * Copyright (C) 2016 George W. Dunlap, Citrix Systems UK Ltd
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; version 2 of the
+ * License only.
+ *
+ * This program 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
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+package xenlight
+
+/*
+#cgo LDFLAGS: -lxenlight -lyajl
+#include <stdlib.h>
+#include <libxl.h>
+*/
+import "C"
+
+import (
+	"fmt"
+	"time"
+	"unsafe"
+)
+
+/*
+ * Types: Builtins
+ */
+type Context struct {
+	ctx *C.libxl_ctx
+}
+
+/*
+ * Context
+ */
+var Ctx Context
+
+func (Ctx *Context) IsOpen() bool {
+	return Ctx.ctx != nil
+}
+
+func (Ctx *Context) Open() (err error) {
+	if Ctx.ctx != nil {
+		return
+	}
+
+	ret := C.libxl_ctx_alloc(unsafe.Pointer(&Ctx.ctx), C.LIBXL_VERSION, 0, nil)
+
+	if ret != 0 {
+		//FIXME: proper error
+		err = createError("Allocating libxl context: ", ret)
+	}
+	return
+}
+
+func (Ctx *Context) Close() (err error) {
+	ret := C.libxl_ctx_free(unsafe.Pointer(Ctx.ctx))
+	Ctx.ctx = nil
+
+	if ret != 0 {
+		//FIXME: proper error
+		err = createError("Freeing libxl context: ", ret)
+	}
+	return
+}
+
+func (Ctx *Context) CheckOpen() (err error) {
+	if Ctx.ctx == nil {
+		err = fmt.Errorf("Context not opened")
+	}
+	return
+}