✏️ 完成插件卸载

dyloader/plugin/plugin_dlopen.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build linux,cgo darwin,cgo freebsd,cgo
 // +build linux,cgo darwin,cgo freebsd,cgo
 
 package plugin
@@ -13,22 +14,8 @@ package plugin
 #include <stdlib.h>
 #include <stdint.h>
 #include <stdio.h>
-static uintptr_t pluginOpen(const char* path, char** err) {
-	void* h = dlopen(path, RTLD_NOW|RTLD_GLOBAL);
-	if (h == NULL) {
-		*err = (char*)dlerror();
-	}
-	return (uintptr_t)h;
-}
-static void* pluginLookup(uintptr_t h, const char* name, char** err) {
-	void* r = dlsym((void*)h, name);
-	if (r == NULL) {
-		*err = (char*)dlerror();
-	}
-	return r;
-}
 static int pluginClose(void* handle, char** err) {
-	int res = dlclose(handle)
+	int res = dlclose(handle);
 	if (res != 0) {
 		*err = (char*)dlerror();
 	}
@@ -43,112 +30,8 @@ import (
 	"unsafe"
 )
 
-func open(name string) (*Plugin, error) {
-	cPath := make([]byte, C.PATH_MAX+1)
-	cRelName := make([]byte, len(name)+1)
-	copy(cRelName, name)
-	if C.realpath(
-		(*C.char)(unsafe.Pointer(&cRelName[0])),
-		(*C.char)(unsafe.Pointer(&cPath[0]))) == nil {
-		return nil, errors.New(`plugin.Open("` + name + `"): realpath failed`)
-	}
-
-	filepath := C.GoString((*C.char)(unsafe.Pointer(&cPath[0])))
-
-	pluginsMu.Lock()
-	if p := plugins[filepath]; p != nil {
-		pluginsMu.Unlock()
-		if p.err != "" {
-			return nil, errors.New(`plugin.Open("` + name + `"): ` + p.err + ` (previous failure)`)
-		}
-		<-p.loaded
-		return p, nil
-	}
-	var cErr *C.char
-	h := C.pluginOpen((*C.char)(unsafe.Pointer(&cPath[0])), &cErr)
-	if h == 0 {
-		pluginsMu.Unlock()
-		return nil, errors.New(`plugin.Open("` + name + `"): ` + C.GoString(cErr))
-	}
-	// TODO(crawshaw): look for plugin note, confirm it is a Go plugin
-	// and it was built with the correct toolchain.
-	if len(name) > 3 && name[len(name)-3:] == ".so" {
-		name = name[:len(name)-3]
-	}
-	if plugins == nil {
-		plugins = make(map[string]*Plugin)
-	}
-	pluginpath, syms, errstr := lastmoduleinit()
-	if errstr != "" {
-		plugins[filepath] = &Plugin{
-			pluginpath: pluginpath,
-			err:        errstr,
-		}
-		pluginsMu.Unlock()
-		return nil, errors.New(`plugin.Open("` + name + `"): ` + errstr)
-	}
-	// This function can be called from the init function of a plugin.
-	// Drop a placeholder in the map so subsequent opens can wait on it.
-	p := &Plugin{
-		pluginpath: pluginpath,
-		loaded:     make(chan struct{}),
-	}
-	plugins[filepath] = p
-	pluginsMu.Unlock()
-
-	initStr := make([]byte, len(pluginpath)+len("..inittask")+1) // +1 for terminating NUL
-	copy(initStr, pluginpath)
-	copy(initStr[len(pluginpath):], "..inittask")
-
-	initTask := C.pluginLookup(h, (*C.char)(unsafe.Pointer(&initStr[0])), &cErr)
-	if initTask != nil {
-		doInit(initTask)
-	}
-
-	// Fill out the value of each plugin symbol.
-	updatedSyms := map[string]interface{}{}
-	for symName, sym := range syms {
-		isFunc := symName[0] == '.'
-		if isFunc {
-			delete(syms, symName)
-			symName = symName[1:]
-		}
-
-		fullName := pluginpath + "." + symName
-		cname := make([]byte, len(fullName)+1)
-		copy(cname, fullName)
-
-		p := C.pluginLookup(h, (*C.char)(unsafe.Pointer(&cname[0])), &cErr)
-		if p == nil {
-			return nil, errors.New(`plugin.Open("` + name + `"): could not find symbol ` + symName + `: ` + C.GoString(cErr))
-		}
-		valp := (*[2]unsafe.Pointer)(unsafe.Pointer(&sym))
-		if isFunc {
-			(*valp)[1] = unsafe.Pointer(&p)
-		} else {
-			(*valp)[1] = p
-		}
-		// we can't add to syms during iteration as we'll end up processing
-		// some symbols twice with the inability to tell if the symbol is a function
-		updatedSyms[symName] = sym
-	}
-	p.syms = updatedSyms
-
-	close(p.loaded)
-	return p, nil
-}
-
-func unload(name string) error {
-	cPath := make([]byte, C.PATH_MAX+1)
-	cRelName := make([]byte, len(name)+1)
-	copy(cRelName, name)
-	if C.realpath(
-		(*C.char)(unsafe.Pointer(&cRelName[0])),
-		(*C.char)(unsafe.Pointer(&cPath[0]))) == nil {
-		return errors.New(`plugin.Close("` + name + `"): realpath failed`)
-	}
-
-	filepath := C.GoString((*C.char)(unsafe.Pointer(&cPath[0])))
+func unload(pg *Plugin) error {
+	filepath := pg.pluginpath
 
 	pluginsMu.Lock()
 	p := plugins[filepath]
@@ -160,27 +43,15 @@ func unload(name string) error {
 		var cErr *C.char
 		res := C.pluginClose(unsafe.Pointer(p), &cErr)
 		if res != 0 {
-			return errors.New(`plugin.Close("` + name + `"): ` + C.GoString(cErr))
+			return errors.New(`plugin.Close("` + filepath + `"): ` + C.GoString(cErr))
 		}
 	}
 	return nil
 }
 
-func lookup(p *Plugin, symName string) (Symbol, error) {
-	if s := p.syms[symName]; s != nil {
-		return s, nil
-	}
-	return nil, errors.New("plugin: symbol " + symName + " not found in plugin " + p.pluginpath)
-}
-
+//go:linkname pluginsMu plugin.pluginsMu
+//go:linkname plugins plugin.plugins
 var (
 	pluginsMu sync.Mutex
 	plugins   map[string]*Plugin
 )
-
-// lastmoduleinit is defined in package runtime
-func lastmoduleinit() (pluginpath string, syms map[string]interface{}, errstr string)
-
-// doInit is defined in package runtime
-//go:linkname doInit runtime.doInit
-func doInit(t unsafe.Pointer) // t should be a *runtime.initTask

dyloader/plugin/plugin_loadlibrary.go

@@ -1,7 +1,4 @@
-// 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.
-
+//go:build windows,cgo
 // +build windows,cgo
 
 package plugin

dyloader/plugin/plugin_stubs.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build !linux,!freebsd,!darwin,!windows !cgo
 // +build !linux,!freebsd,!darwin,!windows !cgo
 
 package plugin

dyloader/plugin/plugin_unix.go

@@ -0,0 +1,89 @@
+// 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.
+//
+// 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.
+//
+// Currently plugins are only supported on Linux, FreeBSD, and macOS.
+// Please report any issues.
+
+//go:build linux,cgo darwin,cgo freebsd,cgo
+// +build linux,cgo darwin,cgo freebsd,cgo
+
+package plugin
+
+import (
+	pl "plugin"
+	"unsafe"
+)
+
+// Plugin is a loaded Go plugin.
+type Plugin struct {
+	pluginpath string
+	err        string        // set if plugin failed to load
+	loaded     chan struct{} // closed when loaded
+	syms       map[string]interface{}
+}
+
+// Open opens a Go plugin.
+// If a path has already been opened, then the existing *Plugin is returned.
+// It is safe for concurrent use by multiple goroutines.
+func Open(path string) (*Plugin, error) {
+	p, err := pl.Open(path)
+	return (*Plugin)(unsafe.Pointer(p)), err
+}
+
+// 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.
+// It is safe for concurrent use by multiple goroutines.
+func (p *Plugin) Lookup(symName string) (Symbol, error) {
+	return (*pl.Plugin)(unsafe.Pointer(p)).Lookup(symName)
+}
+
+// Close closes a Go plugin.
+// If a path is noth opened, it is ignored.
+// It is safe for concurrent use by multiple goroutines.
+func Close(p *Plugin) error {
+	return unload(p)
+}
+
+// A Symbol is a pointer to a variable or function.
+//
+// For example, a plugin defined as
+//
+//	package main
+//
+//	import "fmt"
+//
+//	var V int
+//
+//	func F() { fmt.Printf("Hello, number %d\n", 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{}

dyloader/plugin/plugin.go → dyloader/plugin/plugin_win.go

@@ -15,6 +15,10 @@
 //
 // Currently plugins are only supported on Linux, FreeBSD, and macOS.
 // Please report any issues.
+
+//go:build windows,cgo
+// +build windows,cgo
+
 package plugin
 
 // Plugin is a loaded Go plugin.
@@ -43,8 +47,8 @@ func (p *Plugin) Lookup(symName string) (Symbol, error) {
 // Close closes a Go plugin.
 // If a path is noth opened, it is ignored.
 // It is safe for concurrent use by multiple goroutines.
-func Close(path string) error {
-	return unload(path)
+func Close(p *Plugin) error {
+	return unload(p)
 }
 
 // A Symbol is a pointer to a variable or function.