os,syscall: fix plan 9 build

NewFile take uintptr
make syscall.ProcAttr.Files be []uintptr

R=rsc
CC=golang-dev
https://golang.org/cl/5656073

src/pkg/os/exec_plan9.go

@@ -20,18 +20,10 @@ func StartProcess(name string, argv []string, attr *ProcAttr) (p *Process, err e
 		Sys: attr.Sys,
 	}
 
-	// Create array of integer (system) fds.
-	intfd := make([]int, len(attr.Files))
-	for i, f := range attr.Files {
-		if f == nil {
-			intfd[i] = -1
-		} else {
-			intfd[i] = f.Fd()
-		}
+	for _, f := range attr.Files {
+		sysattr.Files = append(sysattr.Files, f.Fd())
 	}
 
-	sysattr.Files = intfd
-
 	pid, h, e := syscall.StartProcess(name, argv, sysattr)
 	if e != nil {
 		return nil, &PathError{"fork/exec", name, e}

src/pkg/os/file_plan9.go

@@ -26,19 +26,20 @@ type file struct {
 }
 
 // Fd returns the integer Unix file descriptor referencing the open file.
-func (file *File) Fd() int {
-	if file == nil {
-		return -1
+func (f *File) Fd() uintptr {
+	if f == nil {
+		return ^(uintptr(0))
 	}
-	return file.fd
+	return uintptr(f.fd)
 }
 
 // NewFile returns a new File with the given file descriptor and name.
-func NewFile(fd int, name string) *File {
-	if fd < 0 {
+func NewFile(fd uintptr, name string) *File {
+	fdi := int(fd)
+	if fdi < 0 {
 		return nil
 	}
-	f := &File{&file{fd: fd, name: name}}
+	f := &File{&file{fd: fdi, name: name}}
 	runtime.SetFinalizer(f.file, (*file).close)
 	return f
 }
@@ -128,7 +129,7 @@ func OpenFile(name string, flag int, perm FileMode) (file *File, err error) {
 		}
 	}
 
-	return NewFile(fd, name), nil
+	return NewFile(uintptr(fd), name), nil
 }
 
 // Close closes the File, rendering it unusable for I/O.
@@ -330,7 +331,7 @@ func Pipe() (r *File, w *File, err error) {
 	}
 	syscall.ForkLock.RUnlock()
 
-	return NewFile(p[0], "|0"), NewFile(p[1], "|1"), nil
+	return NewFile(uintptr(p[0]), "|0"), NewFile(uintptr(p[1]), "|1"), nil
 }
 
 // not supported on Plan 9

src/pkg/syscall/exec_plan9.go

@@ -182,7 +182,10 @@ func forkAndExecInChild(argv0 *byte, argv []*byte, envv []envItem, dir *byte, at
 	)
 
 	// guard against side effects of shuffling fds below.
-	fd := append([]int(nil), attr.Files...)
+	fd := make([]int, len(attr.Files))
+	for i, ufd := range attr.Files {
+		fd[i] = int(ufd)
+	}
 
 	if envv != nil {
 		clearenv = RFCENVG
@@ -338,9 +341,9 @@ type envItem struct {
 }
 
 type ProcAttr struct {
-	Dir   string   // Current working directory.
-	Env   []string // Environment.
-	Files []int    // File descriptors.
+	Dir   string    // Current working directory.
+	Env   []string  // Environment.
+	Files []uintptr // File descriptors.
 	Sys   *SysProcAttr
 }
 
@@ -423,7 +426,7 @@ func forkExec(argv0 string, argv []string, attr *ProcAttr) (pid int, err error)
 	for _, fd := range openFds {
 		isReserved := false
 		for _, reservedFd := range attr.Files {
-			if fd == reservedFd {
+			if fd == int(reservedFd) {
 				isReserved = true
 				break
 			}