// 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 runtime import "unsafe" //go:linkname plugin_lastmoduleinit plugin.lastmoduleinit func plugin_lastmoduleinit() (path string, syms map[string]any, initTasks []*initTask, errstr string) { var md *moduledata for pmd := firstmoduledata.next; pmd != nil; pmd = pmd.next { if pmd.bad { md = nil // we only want the last module continue } md = pmd } if md == nil { throw("runtime: no plugin module data") } if md.pluginpath == "" { throw("runtime: plugin has empty pluginpath") } if md.typemap != nil { return "", nil, nil, "plugin already loaded" } for _, pmd := range activeModules() { if pmd.pluginpath == md.pluginpath { md.bad = true return "", nil, nil, "plugin already loaded" } if inRange(pmd.text, pmd.etext, md.text, md.etext) || inRange(pmd.bss, pmd.ebss, md.bss, md.ebss) || inRange(pmd.data, pmd.edata, md.data, md.edata) || inRange(pmd.types, pmd.etypes, md.types, md.etypes) { println("plugin: new module data overlaps with previous moduledata") println("\tpmd.text-etext=", hex(pmd.text), "-", hex(pmd.etext)) println("\tpmd.bss-ebss=", hex(pmd.bss), "-", hex(pmd.ebss)) println("\tpmd.data-edata=", hex(pmd.data), "-", hex(pmd.edata)) println("\tpmd.types-etypes=", hex(pmd.types), "-", hex(pmd.etypes)) println("\tmd.text-etext=", hex(md.text), "-", hex(md.etext)) println("\tmd.bss-ebss=", hex(md.bss), "-", hex(md.ebss)) println("\tmd.data-edata=", hex(md.data), "-", hex(md.edata)) println("\tmd.types-etypes=", hex(md.types), "-", hex(md.etypes)) throw("plugin: new module data overlaps with previous moduledata") } } for _, pkghash := range md.pkghashes { if pkghash.linktimehash != *pkghash.runtimehash { md.bad = true return "", nil, nil, "plugin was built with a different version of package " + pkghash.modulename } } // Initialize the freshly loaded module. modulesinit() typelinksinit() pluginftabverify(md) moduledataverify1(md) lock(&itabLock) for _, i := range md.itablinks { itabAdd(i) } unlock(&itabLock) // Build a map of symbol names to symbols. Here in the runtime // we fill out the first word of the interface, the type. We // pass these zero value interfaces to the plugin package, // where the symbol value is filled in (usually via cgo). // // Because functions are handled specially in the plugin package, // function symbol names are prefixed here with '.' to avoid // a dependency on the reflect package. syms = make(map[string]any, len(md.ptab)) for _, ptab := range md.ptab { symName := resolveNameOff(unsafe.Pointer(md.types), ptab.name) t := toRType((*_type)(unsafe.Pointer(md.types))).typeOff(ptab.typ) // TODO can this stack of conversions be simpler? var val any valp := (*[2]unsafe.Pointer)(unsafe.Pointer(&val)) (*valp)[0] = unsafe.Pointer(t) name := symName.Name() if t.Kind_&kindMask == kindFunc { name = "." + name } syms[name] = val } return md.pluginpath, syms, md.inittasks, "" } func pluginftabverify(md *moduledata) { badtable := false for i := 0; i < len(md.ftab); i++ { entry := md.textAddr(md.ftab[i].entryoff) if md.minpc <= entry && entry <= md.maxpc { continue } f := funcInfo{(*_func)(unsafe.Pointer(&md.pclntable[md.ftab[i].funcoff])), md} name := funcname(f) // A common bug is f.entry has a relocation to a duplicate // function symbol, meaning if we search for its PC we get // a valid entry with a name that is useful for debugging. name2 := "none" entry2 := uintptr(0) f2 := findfunc(entry) if f2.valid() { name2 = funcname(f2) entry2 = f2.entry() } badtable = true println("ftab entry", hex(entry), "/", hex(entry2), ": ", name, "/", name2, "outside pc range:[", hex(md.minpc), ",", hex(md.maxpc), "], modulename=", md.modulename, ", pluginpath=", md.pluginpath) } if badtable { throw("runtime: plugin has bad symbol table") } } // inRange reports whether v0 or v1 are in the range [r0, r1]. func inRange(r0, r1, v0, v1 uintptr) bool { return (v0 >= r0 && v0 <= r1) || (v1 >= r0 && v1 <= r1) } // A ptabEntry is generated by the compiler for each exported function // and global variable in the main package of a plugin. It is used to // initialize the plugin module's symbol map. type ptabEntry struct { name nameOff typ typeOff }