1 files changed, 50 insertions, 24 deletions

diff --git a/vendor/golang.org/x/sys/unix/mkpost.go b/vendor/golang.org/x/sys/unix/mkpost.go
index ed50d90..d3ff659 100644
--- a/vendor/golang.org/x/sys/unix/mkpost.go
+++ b/vendor/golang.org/x/sys/unix/mkpost.go
@@ -8,10 +8,11 @@
 // modify the generated types. It is used to clean up
 // the sys API in an architecture specific manner.
 //
-// mkpost is run after cgo -godefs by mkall.sh.
+// mkpost is run after cgo -godefs; see README.md.
 package main
 
 import (
+	"bytes"
 	"fmt"
 	"go/format"
 	"io/ioutil"
@@ -21,42 +22,67 @@ import (
 )
 
 func main() {
+	// Get the OS and architecture (using GOARCH_TARGET if it exists)
+	goos := os.Getenv("GOOS")
+	goarch := os.Getenv("GOARCH_TARGET")
+	if goarch == "" {
+		goarch = os.Getenv("GOARCH")
+	}
+	// Check that we are using the new build system if we should be.
+	if goos == "linux" && goarch != "sparc64" {
+		if os.Getenv("GOLANG_SYS_BUILD") != "docker" {
+			os.Stderr.WriteString("In the new build system, mkpost should not be called directly.\n")
+			os.Stderr.WriteString("See README.md\n")
+			os.Exit(1)
+		}
+	}
+
 	b, err := ioutil.ReadAll(os.Stdin)
 	if err != nil {
 		log.Fatal(err)
 	}
-	s := string(b)
 
-	goarch := os.Getenv("GOARCH")
-	goos := os.Getenv("GOOS")
-	if goarch == "s390x" && goos == "linux" {
-		// Export the types of PtraceRegs fields.
-		re := regexp.MustCompile("ptrace(Psw|Fpregs|Per)")
-		s = re.ReplaceAllString(s, "Ptrace$1")
+	// If we have empty Ptrace structs, we should delete them. Only s390x emits
+	// nonempty Ptrace structs.
+	ptraceRexexp := regexp.MustCompile(`type Ptrace((Psw|Fpregs|Per) struct {\s*})`)
+	b = ptraceRexexp.ReplaceAll(b, nil)
 
-		// Replace padding fields inserted by cgo with blank identifiers.
-		re = regexp.MustCompile("Pad_cgo[A-Za-z0-9_]*")
-		s = re.ReplaceAllString(s, "_")
+	// Replace the control_regs union with a blank identifier for now.
+	controlRegsRegex := regexp.MustCompile(`(Control_regs)\s+\[0\]uint64`)
+	b = controlRegsRegex.ReplaceAll(b, []byte("_ [0]uint64"))
 
-		// Replace other unwanted fields with blank identifiers.
-		re = regexp.MustCompile("X_[A-Za-z0-9_]*")
-		s = re.ReplaceAllString(s, "_")
+	// Remove fields that are added by glibc
+	// Note that this is unstable as the identifers are private.
+	removeFieldsRegex := regexp.MustCompile(`X__glibc\S*`)
+	b = removeFieldsRegex.ReplaceAll(b, []byte("_"))
 
-		// Replace the control_regs union with a blank identifier for now.
-		re = regexp.MustCompile("(Control_regs)\\s+\\[0\\]uint64")
-		s = re.ReplaceAllString(s, "_ [0]uint64")
+	// We refuse to export private fields on s390x
+	if goarch == "s390x" && goos == "linux" {
+		// Remove cgo padding fields
+		removeFieldsRegex := regexp.MustCompile(`Pad_cgo_\d+`)
+		b = removeFieldsRegex.ReplaceAll(b, []byte("_"))
+
+		// Remove padding, hidden, or unused fields
+		removeFieldsRegex = regexp.MustCompile(`X_\S+`)
+		b = removeFieldsRegex.ReplaceAll(b, []byte("_"))
 	}
 
+	// Remove the first line of warning from cgo
+	b = b[bytes.IndexByte(b, '\n')+1:]
+	// Modify the command in the header to include:
+	//  mkpost, our own warning, and a build tag.
+	replacement := fmt.Sprintf(`$1 | go run mkpost.go
+// Code generated by the command above; see README.md. DO NOT EDIT.
+
+// +build %s,%s`, goarch, goos)
+	cgoCommandRegex := regexp.MustCompile(`(cgo -godefs .*)`)
+	b = cgoCommandRegex.ReplaceAll(b, []byte(replacement))
+
 	// gofmt
-	b, err = format.Source([]byte(s))
+	b, err = format.Source(b)
 	if err != nil {
 		log.Fatal(err)
 	}
 
-	// Append this command to the header to show where the new file
-	// came from.
-	re := regexp.MustCompile("(cgo -godefs [a-zA-Z0-9_]+\\.go.*)")
-	b = re.ReplaceAll(b, []byte("$1 | go run mkpost.go"))
-
-	fmt.Printf("%s", b)
+	os.Stdout.Write(b)
 }