syscall: fix mount working directory on Plan 9

In CL 6350, Brad fixed the following system calls
to use the program-wide workding directory:

- bind
- chdir
- create
- open
- remove
- stat
- umount
- wstat

However, Russ Cox pointed out that the mount
system call should be fixed as well.

Change-Id: I6139ed11ba449f18c46e95269f4d0e51be7cec48
Reviewed-on: https://go-review.googlesource.com/6385Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/syscall/syscall_plan9.go

@@ -345,6 +345,12 @@ func Bind(name string, old string, flag int) (err error) {
 	return bind(name, old, flag)
 }
 
+//sys	mount(fd int, afd int, old string, flag int, aname string) (err error)
+func Mount(fd int, afd int, old string, flag int, aname string) (err error) {
+	Fixwd()
+	return mount(fd, afd, old, flag, aname)
+}
+
 //sys	wstat(path string, edir []byte) (err error)
 func Wstat(path string, edir []byte) (err error) {
 	Fixwd()
@@ -356,6 +362,5 @@ func Wstat(path string, edir []byte) (err error) {
 //sys	Pread(fd int, p []byte, offset int64) (n int, err error)
 //sys	Pwrite(fd int, p []byte, offset int64) (n int, err error)
 //sys	Close(fd int) (err error)
-//sys	Mount(fd int, afd int, old string, flag int, aname string) (err error)
 //sys	Fstat(fd int, edir []byte) (n int, err error)
 //sys	Fwstat(fd int, edir []byte) (err error)

src/syscall/zsyscall_plan9_386.go

@@ -145,6 +145,28 @@ func bind(name string, old string, flag int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func mount(fd int, afd int, old string, flag int, aname string) (err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(old)
+	if err != nil {
+		return
+	}
+	var _p1 *byte
+	_p1, err = BytePtrFromString(aname)
+	if err != nil {
+		return
+	}
+	r0, _, e1 := Syscall6(SYS_MOUNT, uintptr(fd), uintptr(afd), uintptr(unsafe.Pointer(_p0)), uintptr(flag), uintptr(unsafe.Pointer(_p1)), 0)
+	use(unsafe.Pointer(_p0))
+	use(unsafe.Pointer(_p1))
+	if int32(r0) == -1 {
+		err = e1
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func wstat(path string, edir []byte) (err error) {
 	var _p0 *byte
 	_p0, err = BytePtrFromString(path)
@@ -238,28 +260,6 @@ func Close(fd int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func Mount(fd int, afd int, old string, flag int, aname string) (err error) {
-	var _p0 *byte
-	_p0, err = BytePtrFromString(old)
-	if err != nil {
-		return
-	}
-	var _p1 *byte
-	_p1, err = BytePtrFromString(aname)
-	if err != nil {
-		return
-	}
-	r0, _, e1 := Syscall6(SYS_MOUNT, uintptr(fd), uintptr(afd), uintptr(unsafe.Pointer(_p0)), uintptr(flag), uintptr(unsafe.Pointer(_p1)), 0)
-	use(unsafe.Pointer(_p0))
-	use(unsafe.Pointer(_p1))
-	if int32(r0) == -1 {
-		err = e1
-	}
-	return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func Fstat(fd int, edir []byte) (n int, err error) {
 	var _p0 unsafe.Pointer
 	if len(edir) > 0 {

src/syscall/zsyscall_plan9_amd64.go

@@ -145,6 +145,28 @@ func bind(name string, old string, flag int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func mount(fd int, afd int, old string, flag int, aname string) (err error) {
+	var _p0 *byte
+	_p0, err = BytePtrFromString(old)
+	if err != nil {
+		return
+	}
+	var _p1 *byte
+	_p1, err = BytePtrFromString(aname)
+	if err != nil {
+		return
+	}
+	r0, _, e1 := Syscall6(SYS_MOUNT, uintptr(fd), uintptr(afd), uintptr(unsafe.Pointer(_p0)), uintptr(flag), uintptr(unsafe.Pointer(_p1)), 0)
+	use(unsafe.Pointer(_p0))
+	use(unsafe.Pointer(_p1))
+	if int32(r0) == -1 {
+		err = e1
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func wstat(path string, edir []byte) (err error) {
 	var _p0 *byte
 	_p0, err = BytePtrFromString(path)
@@ -238,28 +260,6 @@ func Close(fd int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func Mount(fd int, afd int, old string, flag int, aname string) (err error) {
-	var _p0 *byte
-	_p0, err = BytePtrFromString(old)
-	if err != nil {
-		return
-	}
-	var _p1 *byte
-	_p1, err = BytePtrFromString(aname)
-	if err != nil {
-		return
-	}
-	r0, _, e1 := Syscall6(SYS_MOUNT, uintptr(fd), uintptr(afd), uintptr(unsafe.Pointer(_p0)), uintptr(flag), uintptr(unsafe.Pointer(_p1)), 0)
-	use(unsafe.Pointer(_p0))
-	use(unsafe.Pointer(_p1))
-	if int32(r0) == -1 {
-		err = e1
-	}
-	return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func Fstat(fd int, edir []byte) (n int, err error) {
 	var _p0 unsafe.Pointer
 	if len(edir) > 0 {