// Copyright 2009 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 noder
import (
"errors"
"fmt"
"internal/buildcfg"
"internal/exportdata"
"internal/pkgbits"
"os"
pathpkg "path"
"runtime"
"strings"
"unicode"
"unicode/utf8"
"cmd/compile/internal/base"
"cmd/compile/internal/importer"
"cmd/compile/internal/ir"
"cmd/compile/internal/typecheck"
"cmd/compile/internal/types"
"cmd/compile/internal/types2"
"cmd/internal/bio"
"cmd/internal/goobj"
"cmd/internal/objabi"
)
type gcimports struct {
ctxt *types2.Context
packages map[string]*types2.Package
}
func (m *gcimports) Import(path string) (*types2.Package, error) {
return m.ImportFrom(path, "" /* no vendoring */, 0)
}
func (m *gcimports) ImportFrom(path, srcDir string, mode types2.ImportMode) (*types2.Package, error) {
if mode != 0 {
panic("mode must be 0")
}
_, pkg, err := readImportFile(path, typecheck.Target, m.ctxt, m.packages)
return pkg, err
}
func isDriveLetter(b byte) bool {
return 'a' <= b && b <= 'z' || 'A' <= b && b <= 'Z'
}
// is this path a local name? begins with ./ or ../ or /
func islocalname(name string) bool {
return strings.HasPrefix(name, "/") ||
runtime.GOOS == "windows" && len(name) >= 3 && isDriveLetter(name[0]) && name[1] == ':' && name[2] == '/' ||
strings.HasPrefix(name, "./") || name == "." ||
strings.HasPrefix(name, "../") || name == ".."
}
func openPackage(path string) (*os.File, error) {
if islocalname(path) {
if base.Flag.NoLocalImports {
return nil, errors.New("local imports disallowed")
}
if base.Flag.Cfg.PackageFile != nil {
return os.Open(base.Flag.Cfg.PackageFile[path])
}
// try .a before .o. important for building libraries:
// if there is an array.o in the array.a library,
// want to find all of array.a, not just array.o.
if file, err := os.Open(fmt.Sprintf("%s.a", path)); err == nil {
return file, nil
}
if file, err := os.Open(fmt.Sprintf("%s.o", path)); err == nil {
return file, nil
}
return nil, errors.New("file not found")
}
// local imports should be canonicalized already.
// don't want to see "encoding/../encoding/base64"
// as different from "encoding/base64".
if q := pathpkg.Clean(path); q != path {
return nil, fmt.Errorf("non-canonical import path %q (should be %q)", path, q)
}
if base.Flag.Cfg.PackageFile != nil {
return os.Open(base.Flag.Cfg.PackageFile[path])
}
for _, dir := range base.Flag.Cfg.ImportDirs {
if file, err := os.Open(fmt.Sprintf("%s/%s.a", dir, path)); err == nil {
return file, nil
}
if file, err := os.Open(fmt.Sprintf("%s/%s.o", dir, path)); err == nil {
return file, nil
}
}
if buildcfg.GOROOT != "" {
suffix := ""
if base.Flag.InstallSuffix != "" {
suffix = "_" + base.Flag.InstallSuffix
} else if base.Flag.Race {
suffix = "_race"
} else if base.Flag.MSan {
suffix = "_msan"
} else if base.Flag.ASan {
suffix = "_asan"
}
if file, err := os.Open(fmt.Sprintf("%s/pkg/%s_%s%s/%s.a", buildcfg.GOROOT, buildcfg.GOOS, buildcfg.GOARCH, suffix, path)); err == nil {
return file, nil
}
if file, err := os.Open(fmt.Sprintf("%s/pkg/%s_%s%s/%s.o", buildcfg.GOROOT, buildcfg.GOOS, buildcfg.GOARCH, suffix, path)); err == nil {
return file, nil
}
}
return nil, errors.New("file not found")
}
// resolveImportPath resolves an import path as it appears in a Go
// source file to the package's full path.
func resolveImportPath(path string) (string, error) {
// The package name main is no longer reserved,
// but we reserve the import path "main" to identify
// the main package, just as we reserve the import
// path "math" to identify the standard math package.
if path == "main" {
return "", errors.New("cannot import \"main\"")
}
if base.Ctxt.Pkgpath == "" {
panic("missing pkgpath")
}
if path == base.Ctxt.Pkgpath {
return "", fmt.Errorf("import %q while compiling that package (import cycle)", path)
}
if mapped, ok := base.Flag.Cfg.ImportMap[path]; ok {
path = mapped
}
if islocalname(path) {
if path[0] == '/' {
return "", errors.New("import path cannot be absolute path")
}
prefix := base.Flag.D
if prefix == "" {
// Questionable, but when -D isn't specified, historically we
// resolve local import paths relative to the directory the
// compiler's current directory, not the respective source
// file's directory.
prefix = base.Ctxt.Pathname
}
path = pathpkg.Join(prefix, path)
if err := checkImportPath(path, true); err != nil {
return "", err
}
}
return path, nil
}
// readImportFile reads the import file for the given package path and
// returns its types.Pkg representation. If packages is non-nil, the
// types2.Package representation is also returned.
func readImportFile(path string, target *ir.Package, env *types2.Context, packages map[string]*types2.Package) (pkg1 *types.Pkg, pkg2 *types2.Package, err error) {
path, err = resolveImportPath(path)
if err != nil {
return
}
if path == "unsafe" {
pkg1, pkg2 = types.UnsafePkg, types2.Unsafe
// TODO(mdempsky): Investigate if this actually matters. Why would
// the linker or runtime care whether a package imported unsafe?
if !pkg1.Direct {
pkg1.Direct = true
target.Imports = append(target.Imports, pkg1)
}
return
}
pkg1 = types.NewPkg(path, "")
if packages != nil {
pkg2 = packages[path]
assert(pkg1.Direct == (pkg2 != nil && pkg2.Complete()))
}
if pkg1.Direct {
return
}
pkg1.Direct = true
target.Imports = append(target.Imports, pkg1)
f, err := openPackage(path)
if err != nil {
return
}
defer f.Close()
data, err := readExportData(f)
if err != nil {
return
}
if base.Debug.Export != 0 {
fmt.Printf("importing %s (%s)\n", path, f.Name())
}
pr := pkgbits.NewPkgDecoder(pkg1.Path, data)
// Read package descriptors for both types2 and compiler backend.
readPackage(newPkgReader(pr), pkg1, false)
pkg2 = importer.ReadPackage(env, packages, pr)
err = addFingerprint(path, data)
return
}
// readExportData returns the contents of GC-created unified export data.
func readExportData(f *os.File) (data string, err error) {
r := bio.NewReader(f)
sz, err := exportdata.FindPackageDefinition(r.Reader)
if err != nil {
return
}
end := r.Offset() + int64(sz)
abihdr, _, err := exportdata.ReadObjectHeaders(r.Reader)
if err != nil {
return
}
if expect := objabi.HeaderString(); abihdr != expect {
err = fmt.Errorf("object is [%s] expected [%s]", abihdr, expect)
return
}
_, err = exportdata.ReadExportDataHeader(r.Reader)
if err != nil {
return
}
pos := r.Offset()
// Map export data section (+ end-of-section marker) into memory
// as a single large string. This reduces heap fragmentation and
// allows returning individual substrings very efficiently.
var mapped string
mapped, err = base.MapFile(r.File(), pos, end-pos)
if err != nil {
return
}
// check for end-of-section marker "\n$$\n" and remove it
const marker = "\n$$\n"
var ok bool
data, ok = strings.CutSuffix(mapped, marker)
if !ok {
cutoff := data // include last 10 bytes in error message
if len(cutoff) >= 10 {
cutoff = cutoff[len(cutoff)-10:]
}
err = fmt.Errorf("expected $$ marker, but found %q (recompile package)", cutoff)
return
}
return
}
// addFingerprint reads the linker fingerprint included at the end of
// the exportdata.
func addFingerprint(path string, data string) error {
var fingerprint goobj.FingerprintType
pos := len(data) - len(fingerprint)
if pos < 0 {
return fmt.Errorf("missing linker fingerprint in exportdata, but found %q", data)
}
buf := []byte(data[pos:])
copy(fingerprint[:], buf)
base.Ctxt.AddImport(path, fingerprint)
return nil
}
func checkImportPath(path string, allowSpace bool) error {
if path == "" {
return errors.New("import path is empty")
}
if strings.Contains(path, "\x00") {
return errors.New("import path contains NUL")
}
for ri := range base.ReservedImports {
if path == ri {
return fmt.Errorf("import path %q is reserved and cannot be used", path)
}
}
for _, r := range path {
switch {
case r == utf8.RuneError:
return fmt.Errorf("import path contains invalid UTF-8 sequence: %q", path)
case r < 0x20 || r == 0x7f:
return fmt.Errorf("import path contains control character: %q", path)
case r == '\\':
return fmt.Errorf("import path contains backslash; use slash: %q", path)
case !allowSpace && unicode.IsSpace(r):
return fmt.Errorf("import path contains space character: %q", path)
case strings.ContainsRune("!\"#$%&'()*,:;<=>?[]^`{|}", r):
return fmt.Errorf("import path contains invalid character '%c': %q", r, path)
}
}
return nil
}
