diff options
author | Ian Lance Taylor <iant@golang.org> | 2017-01-14 00:05:42 +0000 |
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committer | Ian Lance Taylor <ian@gcc.gnu.org> | 2017-01-14 00:05:42 +0000 |
commit | c2047754c300b68c05d65faa8dc2925fe67b71b4 (patch) | |
tree | e183ae81a1f48a02945cb6de463a70c5be1b06f6 /libgo/go/plugin/plugin_dlopen.go | |
parent | 829afb8f05602bb31c9c597b24df7377fed4f059 (diff) |
libgo: update to Go 1.8 release candidate 1
Compiler changes:
* Change map assignment to use mapassign and assign value directly.
* Change string iteration to use decoderune, faster for ASCII strings.
* Change makeslice to take int, and use makeslice64 for larger values.
* Add new noverflow field to hmap struct used for maps.
Unresolved problems, to be fixed later:
* Commented out test in go/types/sizes_test.go that doesn't compile.
* Commented out reflect.TestStructOf test for padding after zero-sized field.
Reviewed-on: https://go-review.googlesource.com/35231
gotools/:
Updates for Go 1.8rc1.
* Makefile.am (go_cmd_go_files): Add bug.go.
(s-zdefaultcc): Write defaultPkgConfig.
* Makefile.in: Rebuild.
From-SVN: r244456
Diffstat (limited to 'libgo/go/plugin/plugin_dlopen.go')
-rw-r--r-- | libgo/go/plugin/plugin_dlopen.go | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/libgo/go/plugin/plugin_dlopen.go b/libgo/go/plugin/plugin_dlopen.go new file mode 100644 index 00000000000..c5b0a4721c5 --- /dev/null +++ b/libgo/go/plugin/plugin_dlopen.go @@ -0,0 +1,138 @@ +// 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. + +// +build linux,cgo darwin,cgo + +package plugin + +/* +#cgo linux LDFLAGS: -ldl +#include <dlfcn.h> +#include <limits.h> +#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; +} +*/ +import "C" + +import ( + "errors" + "sync" + "unsafe" +) + +func open(name string) (*Plugin, error) { + cPath := (*C.char)(C.malloc(C.PATH_MAX + 1)) + defer C.free(unsafe.Pointer(cPath)) + + cRelName := C.CString(name) + defer C.free(unsafe.Pointer(cRelName)) + if C.realpath(cRelName, cPath) == nil { + return nil, errors.New("plugin.Open(" + name + "): realpath failed") + } + + filepath := C.GoString(cPath) + + pluginsMu.Lock() + if p := plugins[filepath]; p != nil { + pluginsMu.Unlock() + <-p.loaded + return p, nil + } + var cErr *C.char + h := C.pluginOpen(cPath, &cErr) + if h == 0 { + pluginsMu.Unlock() + return nil, errors.New("plugin.Open: " + 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] + } + + pluginpath, syms, mismatchpkg := lastmoduleinit() + if mismatchpkg != "" { + pluginsMu.Unlock() + return nil, errors.New("plugin.Open: plugin was built with a different version of package " + mismatchpkg) + } + if plugins == nil { + plugins = make(map[string]*Plugin) + } + // 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{}), + syms: syms, + } + plugins[filepath] = p + pluginsMu.Unlock() + + initStr := C.CString(pluginpath + ".init") + initFuncPC := C.pluginLookup(h, initStr, &cErr) + C.free(unsafe.Pointer(initStr)) + if initFuncPC != nil { + initFuncP := &initFuncPC + initFunc := *(*func())(unsafe.Pointer(&initFuncP)) + initFunc() + } + + // Fill out the value of each plugin symbol. + for symName, sym := range syms { + isFunc := symName[0] == '.' + if isFunc { + delete(syms, symName) + symName = symName[1:] + } + + cname := C.CString(pluginpath + "." + symName) + p := C.pluginLookup(h, cname, &cErr) + C.free(unsafe.Pointer(cname)) + if p == nil { + return nil, errors.New("plugin.Open: 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 + } + syms[symName] = sym + } + close(p.loaded) + return p, 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) +} + +var ( + pluginsMu sync.Mutex + plugins map[string]*Plugin +) + +// lastmoduleinit is defined in package runtime +func lastmoduleinit() (pluginpath string, syms map[string]interface{}, mismatchpkg string) |