1 files changed, 103 insertions, 0 deletions

diff --git a/vendor/golang.org/x/sys/unix/linux/mkall.go b/vendor/golang.org/x/sys/unix/linux/mkall.go
index 429754f16..89b2fe886 100644
--- a/vendor/golang.org/x/sys/unix/linux/mkall.go
+++ b/vendor/golang.org/x/sys/unix/linux/mkall.go
@@ -15,12 +15,17 @@
 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.
@@ -128,6 +133,15 @@ var targets = []target{
 	// },
 }
 
+// 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",
@@ -158,6 +172,18 @@ func main() {
 			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
@@ -377,3 +403,80 @@ func (t *target) mksyscallFlags() (flags []string) {
 	}
 	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")
+}