From 0cbb12f0bbaeb3893b3d011fdb1a270291747ab0 Mon Sep 17 00:00:00 2001 From: David Crawshaw Date: Fri, 26 Aug 2016 08:50:50 -0400 Subject: plugin: new package for loading plugins Includes a linux implementation. Change-Id: Iacc2ed7da760ae9deebc928adf2b334b043b07ec Reviewed-on: https://go-review.googlesource.com/27823 Run-TryBot: David Crawshaw TryBot-Result: Gobot Gobot Reviewed-by: Ian Lance Taylor --- src/plugin/plugin.go | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+) create mode 100644 src/plugin/plugin.go (limited to 'src/plugin/plugin.go') diff --git a/src/plugin/plugin.go b/src/plugin/plugin.go new file mode 100644 index 0000000000..66cf2f98d4 --- /dev/null +++ b/src/plugin/plugin.go @@ -0,0 +1,70 @@ +// Copyright 2016 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// Package plugin implements loading and symbol resolution of Go plugins. +// +// Currently plugins only work on Linux. +// +// A plugin is a Go main package with exported functions and variables that +// has been built with: +// +// go build -buildmode=plugin +// +// When a plugin is first opened, the init functions of all packages not +// already part of the program are called. The main function is not run. +// A plugin is only initialized once, and cannot be closed. +package plugin + +// Plugin is a loaded Go plugin. +type Plugin struct { + name string + loaded chan struct{} // closed when loaded + syms map[string]interface{} +} + +// Open opens a Go plugin. +func Open(path string) (*Plugin, error) { + return open(path) +} + +// Lookup searches for a symbol named symName in plugin p. +// A symbol is any exported variable or function. +// It reports an error if the symbol is not found. +func (p *Plugin) Lookup(symName string) (Symbol, error) { + return lookup(p, symName) +} + +// A Symbol is a pointer to a variable or function. +// +// For example, a plugin defined as +// +// package main +// +// // // No C code needed. +// import "C" +// +// import "fmt" +// +// var V int +// +// func F() { fmt.Println("Hello, number %d", V) } +// +// may be loaded with the Open function and then the exported package +// symbols V and F can be accessed +// +// p, err := plugin.Open("plugin_name.so") +// if err != nil { +// panic(err) +// } +// v, err := p.Lookup("V") +// if err != nil { +// panic(err) +// } +// f, err := p.Lookup("F") +// if err != nil { +// panic(err) +// } +// *v.(*int) = 7 +// f.(func())() // prints "Hello, number 7" +type Symbol interface{} -- cgit v1.3