mirror of
https://github.com/golang/go
synced 2024-10-01 16:08:33 -06:00
f895b43688
This removes much of the AST logic out of main.go, and makes it easier to build custom vet binaries The trade-off in this change is for flexibility. There's very little change in the per-check files, a lot less code in main.go (specifically the AST walking logic has shrunk), and it makes it much easier to build custom vet binaries simply by dropping new source files in the directory. LGTM=josharian, r R=r, josharian, kamil.kisiel CC=golang-codereviews https://golang.org/cl/83400043
99 lines
2.7 KiB
Go
99 lines
2.7 KiB
Go
// Copyright 2014 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Check for invalid uintptr -> unsafe.Pointer conversions.
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package main
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import (
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"go/ast"
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"go/token"
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"code.google.com/p/go.tools/go/types"
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)
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func init() {
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register("unsafeptr",
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"check for misuse of unsafe.Pointer",
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checkUnsafePointer,
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callExpr)
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}
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func checkUnsafePointer(f *File, node ast.Node) {
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x := node.(*ast.CallExpr)
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if len(x.Args) != 1 {
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return
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}
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if f.hasBasicType(x.Fun, types.UnsafePointer) && f.hasBasicType(x.Args[0], types.Uintptr) && !f.isSafeUintptr(x.Args[0]) {
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f.Badf(x.Pos(), "possible misuse of unsafe.Pointer")
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}
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}
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// isSafeUintptr reports whether x - already known to be a uintptr -
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// is safe to convert to unsafe.Pointer. It is safe if x is itself derived
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// directly from an unsafe.Pointer via conversion and pointer arithmetic
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// or if x is the result of reflect.Value.Pointer or reflect.Value.UnsafeAddr
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// or obtained from the Data field of a *reflect.SliceHeader or *reflect.StringHeader.
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func (f *File) isSafeUintptr(x ast.Expr) bool {
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switch x := x.(type) {
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case *ast.ParenExpr:
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return f.isSafeUintptr(x.X)
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case *ast.SelectorExpr:
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switch x.Sel.Name {
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case "Data":
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// reflect.SliceHeader and reflect.StringHeader are okay,
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// but only if they are pointing at a real slice or string.
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// It's not okay to do:
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// var x SliceHeader
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// x.Data = uintptr(unsafe.Pointer(...))
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// ... use x ...
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// p := unsafe.Pointer(x.Data)
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// because in the middle the garbage collector doesn't
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// see x.Data as a pointer and so x.Data may be dangling
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// by the time we get to the conversion at the end.
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// For now approximate by saying that *Header is okay
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// but Header is not.
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pt, ok := f.pkg.types[x.X].Type.(*types.Pointer)
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if ok {
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t, ok := pt.Elem().(*types.Named)
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if ok && t.Obj().Pkg().Path() == "reflect" {
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switch t.Obj().Name() {
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case "StringHeader", "SliceHeader":
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return true
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}
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}
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}
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}
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case *ast.CallExpr:
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switch len(x.Args) {
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case 0:
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// maybe call to reflect.Value.Pointer or reflect.Value.UnsafeAddr.
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sel, ok := x.Fun.(*ast.SelectorExpr)
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if !ok {
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break
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}
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switch sel.Sel.Name {
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case "Pointer", "UnsafeAddr":
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t, ok := f.pkg.types[sel.X].Type.(*types.Named)
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if ok && t.Obj().Pkg().Path() == "reflect" && t.Obj().Name() == "Value" {
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return true
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}
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}
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case 1:
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// maybe conversion of uintptr to unsafe.Pointer
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return f.hasBasicType(x.Fun, types.Uintptr) && f.hasBasicType(x.Args[0], types.UnsafePointer)
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}
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case *ast.BinaryExpr:
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switch x.Op {
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case token.ADD, token.SUB:
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return f.isSafeUintptr(x.X) && !f.isSafeUintptr(x.Y)
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}
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}
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return false
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}
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