syncthing/vendor/golang.org/x/sys/unix/linux/mkall.go

483 lines
14 KiB
Go

// Copyright 2017 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.
// linux/mkall.go - Generates all Linux zsysnum, zsyscall, zerror, and ztype
// files for all 11 linux architectures supported by the go compiler. See
// README.md for more information about the build system.
// To run it you must have a git checkout of the Linux kernel and glibc. Once
// the appropriate sources are ready, the program is run as:
// go run linux/mkall.go <linux_dir> <glibc_dir>
// +build ignore
package main
import (
"bufio"
"bytes"
"fmt"
"io"
"io/ioutil"
"os"
"os/exec"
"path/filepath"
"runtime"
"strings"
"unicode"
)
// These will be paths to the appropriate source directories.
var LinuxDir string
var GlibcDir string
const TempDir = "/tmp"
const IncludeDir = TempDir + "/include" // To hold our C headers
const BuildDir = TempDir + "/build" // To hold intermediate build files
const GOOS = "linux" // Only for Linux targets
const BuildArch = "amd64" // Must be built on this architecture
const MinKernel = "2.6.23" // https://golang.org/doc/install#requirements
type target struct {
GoArch string // Architecture name according to Go
LinuxArch string // Architecture name according to the Linux Kernel
GNUArch string // Architecture name according to GNU tools (https://wiki.debian.org/Multiarch/Tuples)
BigEndian bool // Default Little Endian
SignedChar bool // Is -fsigned-char needed (default no)
Bits int
}
// List of the 11 Linux targets supported by the go compiler. sparc64 is not
// currently supported, though a port is in progress.
var targets = []target{
{
GoArch: "386",
LinuxArch: "x86",
GNUArch: "i686-linux-gnu", // Note "i686" not "i386"
Bits: 32,
},
{
GoArch: "amd64",
LinuxArch: "x86",
GNUArch: "x86_64-linux-gnu",
Bits: 64,
},
{
GoArch: "arm64",
LinuxArch: "arm64",
GNUArch: "aarch64-linux-gnu",
SignedChar: true,
Bits: 64,
},
{
GoArch: "arm",
LinuxArch: "arm",
GNUArch: "arm-linux-gnueabi",
Bits: 32,
},
{
GoArch: "mips",
LinuxArch: "mips",
GNUArch: "mips-linux-gnu",
BigEndian: true,
Bits: 32,
},
{
GoArch: "mipsle",
LinuxArch: "mips",
GNUArch: "mipsel-linux-gnu",
Bits: 32,
},
{
GoArch: "mips64",
LinuxArch: "mips",
GNUArch: "mips64-linux-gnuabi64",
BigEndian: true,
Bits: 64,
},
{
GoArch: "mips64le",
LinuxArch: "mips",
GNUArch: "mips64el-linux-gnuabi64",
Bits: 64,
},
{
GoArch: "ppc64",
LinuxArch: "powerpc",
GNUArch: "powerpc64-linux-gnu",
BigEndian: true,
Bits: 64,
},
{
GoArch: "ppc64le",
LinuxArch: "powerpc",
GNUArch: "powerpc64le-linux-gnu",
Bits: 64,
},
{
GoArch: "s390x",
LinuxArch: "s390",
GNUArch: "s390x-linux-gnu",
BigEndian: true,
SignedChar: true,
Bits: 64,
},
// {
// GoArch: "sparc64",
// LinuxArch: "sparc",
// GNUArch: "sparc64-linux-gnu",
// BigEndian: true,
// Bits: 64,
// },
}
// ptracePairs is a list of pairs of targets that can, in some cases,
// run each other's binaries.
var ptracePairs = []struct{ a1, a2 string }{
{"386", "amd64"},
{"arm", "arm64"},
{"mips", "mips64"},
{"mipsle", "mips64le"},
}
func main() {
if runtime.GOOS != GOOS || runtime.GOARCH != BuildArch {
fmt.Printf("Build system has GOOS_GOARCH = %s_%s, need %s_%s\n",
runtime.GOOS, runtime.GOARCH, GOOS, BuildArch)
return
}
// Check that we are using the new build system if we should
if os.Getenv("GOLANG_SYS_BUILD") != "docker" {
fmt.Println("In the new build system, mkall.go should not be called directly.")
fmt.Println("See README.md")
return
}
// Parse the command line options
if len(os.Args) != 3 {
fmt.Println("USAGE: go run linux/mkall.go <linux_dir> <glibc_dir>")
return
}
LinuxDir = os.Args[1]
GlibcDir = os.Args[2]
for _, t := range targets {
fmt.Printf("----- GENERATING: %s -----\n", t.GoArch)
if err := t.generateFiles(); err != nil {
fmt.Printf("%v\n***** FAILURE: %s *****\n\n", err, t.GoArch)
} else {
fmt.Printf("----- SUCCESS: %s -----\n\n", t.GoArch)
}
}
fmt.Printf("----- GENERATING ptrace pairs -----\n")
ok := true
for _, p := range ptracePairs {
if err := generatePtracePair(p.a1, p.a2); err != nil {
fmt.Printf("%v\n***** FAILURE: %s/%s *****\n\n", err, p.a1, p.a2)
ok = false
}
}
if ok {
fmt.Printf("----- SUCCESS ptrace pairs -----\n\n")
}
}
// Makes an exec.Cmd with Stderr attached to os.Stderr
func makeCommand(name string, args ...string) *exec.Cmd {
cmd := exec.Command(name, args...)
cmd.Stderr = os.Stderr
return cmd
}
// Runs the command, pipes output to a formatter, pipes that to an output file.
func (t *target) commandFormatOutput(formatter string, outputFile string,
name string, args ...string) (err error) {
mainCmd := makeCommand(name, args...)
fmtCmd := makeCommand(formatter)
if formatter == "mkpost" {
fmtCmd = makeCommand("go", "run", "mkpost.go")
// Set GOARCH_TARGET so mkpost knows what GOARCH is..
fmtCmd.Env = append(os.Environ(), "GOARCH_TARGET="+t.GoArch)
// Set GOARCH to host arch for mkpost, so it can run natively.
for i, s := range fmtCmd.Env {
if strings.HasPrefix(s, "GOARCH=") {
fmtCmd.Env[i] = "GOARCH=" + BuildArch
}
}
}
// mainCmd | fmtCmd > outputFile
if fmtCmd.Stdin, err = mainCmd.StdoutPipe(); err != nil {
return
}
if fmtCmd.Stdout, err = os.Create(outputFile); err != nil {
return
}
// Make sure the formatter eventually closes
if err = fmtCmd.Start(); err != nil {
return
}
defer func() {
fmtErr := fmtCmd.Wait()
if err == nil {
err = fmtErr
}
}()
return mainCmd.Run()
}
// Generates all the files for a Linux target
func (t *target) generateFiles() error {
// Setup environment variables
os.Setenv("GOOS", GOOS)
os.Setenv("GOARCH", t.GoArch)
// Get appropriate compiler and emulator (unless on x86)
if t.LinuxArch != "x86" {
// Check/Setup cross compiler
compiler := t.GNUArch + "-gcc"
if _, err := exec.LookPath(compiler); err != nil {
return err
}
os.Setenv("CC", compiler)
// Check/Setup emulator (usually first component of GNUArch)
qemuArchName := t.GNUArch[:strings.Index(t.GNUArch, "-")]
if t.LinuxArch == "powerpc" {
qemuArchName = t.GoArch
}
os.Setenv("GORUN", "qemu-"+qemuArchName)
} else {
os.Setenv("CC", "gcc")
}
// Make the include directory and fill it with headers
if err := os.MkdirAll(IncludeDir, os.ModePerm); err != nil {
return err
}
defer os.RemoveAll(IncludeDir)
if err := t.makeHeaders(); err != nil {
return fmt.Errorf("could not make header files: %v", err)
}
fmt.Println("header files generated")
// Make each of the four files
if err := t.makeZSysnumFile(); err != nil {
return fmt.Errorf("could not make zsysnum file: %v", err)
}
fmt.Println("zsysnum file generated")
if err := t.makeZSyscallFile(); err != nil {
return fmt.Errorf("could not make zsyscall file: %v", err)
}
fmt.Println("zsyscall file generated")
if err := t.makeZTypesFile(); err != nil {
return fmt.Errorf("could not make ztypes file: %v", err)
}
fmt.Println("ztypes file generated")
if err := t.makeZErrorsFile(); err != nil {
return fmt.Errorf("could not make zerrors file: %v", err)
}
fmt.Println("zerrors file generated")
return nil
}
// Create the Linux and glibc headers in the include directory.
func (t *target) makeHeaders() error {
// Make the Linux headers we need for this architecture
linuxMake := makeCommand("make", "headers_install", "ARCH="+t.LinuxArch, "INSTALL_HDR_PATH="+TempDir)
linuxMake.Dir = LinuxDir
if err := linuxMake.Run(); err != nil {
return err
}
// A Temporary build directory for glibc
if err := os.MkdirAll(BuildDir, os.ModePerm); err != nil {
return err
}
defer os.RemoveAll(BuildDir)
// Make the glibc headers we need for this architecture
confScript := filepath.Join(GlibcDir, "configure")
glibcConf := makeCommand(confScript, "--prefix="+TempDir, "--host="+t.GNUArch, "--enable-kernel="+MinKernel)
glibcConf.Dir = BuildDir
if err := glibcConf.Run(); err != nil {
return err
}
glibcMake := makeCommand("make", "install-headers")
glibcMake.Dir = BuildDir
if err := glibcMake.Run(); err != nil {
return err
}
// We only need an empty stubs file
stubsFile := filepath.Join(IncludeDir, "gnu/stubs.h")
if file, err := os.Create(stubsFile); err != nil {
return err
} else {
file.Close()
}
return nil
}
// makes the zsysnum_linux_$GOARCH.go file
func (t *target) makeZSysnumFile() error {
zsysnumFile := fmt.Sprintf("zsysnum_linux_%s.go", t.GoArch)
unistdFile := filepath.Join(IncludeDir, "asm/unistd.h")
args := append(t.cFlags(), unistdFile)
return t.commandFormatOutput("gofmt", zsysnumFile, "linux/mksysnum.pl", args...)
}
// makes the zsyscall_linux_$GOARCH.go file
func (t *target) makeZSyscallFile() error {
zsyscallFile := fmt.Sprintf("zsyscall_linux_%s.go", t.GoArch)
// Find the correct architecture syscall file (might end with x.go)
archSyscallFile := fmt.Sprintf("syscall_linux_%s.go", t.GoArch)
if _, err := os.Stat(archSyscallFile); os.IsNotExist(err) {
shortArch := strings.TrimSuffix(t.GoArch, "le")
archSyscallFile = fmt.Sprintf("syscall_linux_%sx.go", shortArch)
}
args := append(t.mksyscallFlags(), "-tags", "linux,"+t.GoArch,
"syscall_linux.go", archSyscallFile)
return t.commandFormatOutput("gofmt", zsyscallFile, "./mksyscall.pl", args...)
}
// makes the zerrors_linux_$GOARCH.go file
func (t *target) makeZErrorsFile() error {
zerrorsFile := fmt.Sprintf("zerrors_linux_%s.go", t.GoArch)
return t.commandFormatOutput("gofmt", zerrorsFile, "./mkerrors.sh", t.cFlags()...)
}
// makes the ztypes_linux_$GOARCH.go file
func (t *target) makeZTypesFile() error {
ztypesFile := fmt.Sprintf("ztypes_linux_%s.go", t.GoArch)
args := []string{"tool", "cgo", "-godefs", "--"}
args = append(args, t.cFlags()...)
args = append(args, "linux/types.go")
return t.commandFormatOutput("mkpost", ztypesFile, "go", args...)
}
// Flags that should be given to gcc and cgo for this target
func (t *target) cFlags() []string {
// Compile statically to avoid cross-architecture dynamic linking.
flags := []string{"-Wall", "-Werror", "-static", "-I" + IncludeDir}
// Architecture-specific flags
if t.SignedChar {
flags = append(flags, "-fsigned-char")
}
if t.LinuxArch == "x86" {
flags = append(flags, fmt.Sprintf("-m%d", t.Bits))
}
return flags
}
// Flags that should be given to mksyscall for this target
func (t *target) mksyscallFlags() (flags []string) {
if t.Bits == 32 {
if t.BigEndian {
flags = append(flags, "-b32")
} else {
flags = append(flags, "-l32")
}
}
// This flag menas a 64-bit value should use (even, odd)-pair.
if t.GoArch == "arm" || (t.LinuxArch == "mips" && t.Bits == 32) {
flags = append(flags, "-arm")
}
return
}
// generatePtracePair takes a pair of GOARCH values that can run each
// other's binaries, such as 386 and amd64. It extracts the PtraceRegs
// type for each one. It writes a new file defining the types
// PtraceRegsArch1 and PtraceRegsArch2 and the corresponding functions
// Ptrace{Get,Set}Regs{arch1,arch2}. This permits debugging the other
// binary on a native system.
func generatePtracePair(arch1, arch2 string) error {
def1, err := ptraceDef(arch1)
if err != nil {
return err
}
def2, err := ptraceDef(arch2)
if err != nil {
return err
}
f, err := os.Create(fmt.Sprintf("zptrace%s_linux.go", arch1))
if err != nil {
return err
}
buf := bufio.NewWriter(f)
fmt.Fprintf(buf, "// Code generated by linux/mkall.go generatePtracePair(%s, %s). DO NOT EDIT.\n", arch1, arch2)
fmt.Fprintf(buf, "\n")
fmt.Fprintf(buf, "// +build linux\n")
fmt.Fprintf(buf, "// +build %s %s\n", arch1, arch2)
fmt.Fprintf(buf, "\n")
fmt.Fprintf(buf, "package unix\n")
fmt.Fprintf(buf, "\n")
fmt.Fprintf(buf, "%s\n", `import "unsafe"`)
fmt.Fprintf(buf, "\n")
writeOnePtrace(buf, arch1, def1)
fmt.Fprintf(buf, "\n")
writeOnePtrace(buf, arch2, def2)
if err := buf.Flush(); err != nil {
return err
}
if err := f.Close(); err != nil {
return err
}
return nil
}
// ptraceDef returns the definition of PtraceRegs for arch.
func ptraceDef(arch string) (string, error) {
filename := fmt.Sprintf("ztypes_linux_%s.go", arch)
data, err := ioutil.ReadFile(filename)
if err != nil {
return "", fmt.Errorf("reading %s: %v", filename, err)
}
start := bytes.Index(data, []byte("type PtraceRegs struct"))
if start < 0 {
return "", fmt.Errorf("%s: no definition of PtraceRegs", filename)
}
data = data[start:]
end := bytes.Index(data, []byte("\n}\n"))
if end < 0 {
return "", fmt.Errorf("%s: can't find end of PtraceRegs definition", filename)
}
return string(data[:end+2]), nil
}
// writeOnePtrace writes out the ptrace definitions for arch.
func writeOnePtrace(w io.Writer, arch, def string) {
uarch := string(unicode.ToUpper(rune(arch[0]))) + arch[1:]
fmt.Fprintf(w, "// PtraceRegs%s is the registers used by %s binaries.\n", uarch, arch)
fmt.Fprintf(w, "%s\n", strings.Replace(def, "PtraceRegs", "PtraceRegs"+uarch, 1))
fmt.Fprintf(w, "\n")
fmt.Fprintf(w, "// PtraceGetRegs%s fetches the registers used by %s binaries.\n", uarch, arch)
fmt.Fprintf(w, "func PtraceGetRegs%s(pid int, regsout *PtraceRegs%s) error {\n", uarch, uarch)
fmt.Fprintf(w, "\treturn ptrace(PTRACE_GETREGS, pid, 0, uintptr(unsafe.Pointer(regsout)))\n")
fmt.Fprintf(w, "}\n")
fmt.Fprintf(w, "\n")
fmt.Fprintf(w, "// PtraceSetRegs%s sets the registers used by %s binaries.\n", uarch, arch)
fmt.Fprintf(w, "func PtraceSetRegs%s(pid int, regs *PtraceRegs%s) error {\n", uarch, uarch)
fmt.Fprintf(w, "\treturn ptrace(PTRACE_SETREGS, pid, 0, uintptr(unsafe.Pointer(regs)))\n")
fmt.Fprintf(w, "}\n")
}