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// 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]interface{}, 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, "plugin already loaded"
}
for _, pmd := range activeModules() {
if pmd.pluginpath == md.pluginpath {
md.bad = true
return "", 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, "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]interface{}, len(md.ptab))
for _, ptab := range md.ptab {
symName := resolveNameOff(unsafe.Pointer(md.types), ptab.name)
t := (*_type)(unsafe.Pointer(md.types)).typeOff(ptab.typ)
var val interface{}
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, ""
}
func pluginftabverify(md *moduledata) {
badtable := false
for i := 0; i < len(md.ftab); i++ {
entry := md.ftab[i].entry
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 outside pc range: ", hex(entry), "/", hex(entry2), ": ", name, "/", name2)
}
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
}
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