Merge pull request #1087 from ivandeex/openbsd-process-nocgo

process, v3/process (openbsd):  remove remaining CGO bits from CmdlineSliceWithContext

Makefile

@@ -58,6 +58,10 @@ vet:
 	GOOS=linux GOARCH=s390x go vet ./...
 
 	GOOS=netbsd GOARCH=amd64 go vet ./...
+
+	GOOS=openbsd GOARCH=386 go vet ./...
+	GOOS=openbsd GOARCH=amd64 go vet ./...
+
 	GOOS=solaris GOARCH=amd64 go vet ./...
 
 	GOOS=windows GOARCH=amd64 go vet ./...

process/process_openbsd.go

@@ -3,8 +3,11 @@
 package process
 
 import (
-	"C"
+	"bytes"
 	"context"
+	"encoding/binary"
+	"fmt"
+	"io"
 	"os/exec"
 	"path/filepath"
 	"strconv"
@@ -78,19 +81,49 @@ func (p *Process) CmdlineSliceWithContext(ctx context.Context) ([]string, error)
 		return nil, err
 	}
 
-	argc := 0
-	argvp := unsafe.Pointer(&buf[0])
-	argv := *(**C.char)(unsafe.Pointer(argvp))
-	size := unsafe.Sizeof(argv)
+	/* From man sysctl(2):
+	The buffer pointed to by oldp is filled with an array of char
+	pointers followed by the strings themselves. The last char
+	pointer is a NULL pointer. */
 	var strParts []string
+	r := bytes.NewReader(buf)
+	baseAddr := uintptr(unsafe.Pointer(&buf[0]))
+	for {
+		argvp, err := readPtr(r)
+		if err != nil {
+			return nil, err
+		}
+		if argvp == 0 { // check for a NULL pointer
+			break
+		}
+		offset := argvp - baseAddr
+		length := uintptr(bytes.IndexByte(buf[offset:], 0))
+		str := string(buf[offset : offset+length])
+		strParts = append(strParts, str)
+	}
 
-	for argv != nil {
-		strParts = append(strParts, C.GoString(argv))
+	return strParts, nil
+}
 
-		argc++
-		argv = *(**C.char)(unsafe.Pointer(uintptr(argvp) + uintptr(argc)*size))
+// readPtr reads a pointer data from a given reader. WARNING: only little
+// endian architectures are supported.
+func readPtr(r io.Reader) (uintptr, error) {
+	switch sizeofPtr {
+	case 4:
+		var p uint32
+		if err := binary.Read(r, binary.LittleEndian, &p); err != nil {
+			return 0, err
+		}
+		return uintptr(p), nil
+	case 8:
+		var p uint64
+		if err := binary.Read(r, binary.LittleEndian, &p); err != nil {
+			return 0, err
+		}
+		return uintptr(p), nil
+	default:
+		return 0, fmt.Errorf("unsupported pointer size")
 	}
-	return strParts, nil
 }
 
 func (p *Process) CmdlineWithContext(ctx context.Context) (string, error) {

v3/process/process_openbsd.go

@@ -3,8 +3,11 @@
 package process
 
 import (
-	"C"
+	"bytes"
 	"context"
+	"encoding/binary"
+	"fmt"
+	"io"
 	"os/exec"
 	"path/filepath"
 	"strconv"
@@ -78,19 +81,49 @@ func (p *Process) CmdlineSliceWithContext(ctx context.Context) ([]string, error)
 		return nil, err
 	}
 
-	argc := 0
-	argvp := unsafe.Pointer(&buf[0])
-	argv := *(**C.char)(unsafe.Pointer(argvp))
-	size := unsafe.Sizeof(argv)
+	/* From man sysctl(2):
+	The buffer pointed to by oldp is filled with an array of char
+	pointers followed by the strings themselves. The last char
+	pointer is a NULL pointer. */
 	var strParts []string
+	r := bytes.NewReader(buf)
+	baseAddr := uintptr(unsafe.Pointer(&buf[0]))
+	for {
+		argvp, err := readPtr(r)
+		if err != nil {
+			return nil, err
+		}
+		if argvp == 0 { // check for a NULL pointer
+			break
+		}
+		offset := argvp - baseAddr
+		length := uintptr(bytes.IndexByte(buf[offset:], 0))
+		str := string(buf[offset : offset+length])
+		strParts = append(strParts, str)
+	}
 
-	for argv != nil {
-		strParts = append(strParts, C.GoString(argv))
+	return strParts, nil
+}
 
-		argc++
-		argv = *(**C.char)(unsafe.Pointer(uintptr(argvp) + uintptr(argc)*size))
+// readPtr reads a pointer data from a given reader. WARNING: only little
+// endian architectures are supported.
+func readPtr(r io.Reader) (uintptr, error) {
+	switch sizeofPtr {
+	case 4:
+		var p uint32
+		if err := binary.Read(r, binary.LittleEndian, &p); err != nil {
+			return 0, err
+		}
+		return uintptr(p), nil
+	case 8:
+		var p uint64
+		if err := binary.Read(r, binary.LittleEndian, &p); err != nil {
+			return 0, err
+		}
+		return uintptr(p), nil
+	default:
+		return 0, fmt.Errorf("unsupported pointer size")
 	}
-	return strParts, nil
 }
 
 func (p *Process) CmdlineWithContext(ctx context.Context) (string, error) {