unix: match ioctl req argument type to libc type

On Solaris, AIX, and zOS, the req argument of ioctl() is a signed int,
not an unsigned long like on other platforms, which means many constants
are negative, causing friction when passing them to a uint argument.
Correct the signature of these functions to pass the req argument as
signed, just like libc.

Fixes golang/go#59030.

Change-Id: Ia14e92a150f4b5fb9488c5032ca296cb786e9811
Reviewed-on: https://go-review.googlesource.com/c/sys/+/476515
Reviewed-by: Ian Lance Taylor <[email protected]>
Reviewed-by: Bryan Mills <[email protected]>
Run-TryBot: Jason Donenfeld <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Reviewed-by: Nahum Shalman <[email protected]>

Author: zx2c4

unix/ioctl_signed.go

@@ -0,0 +1,70 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build aix || solaris
+// +build aix solaris
+
+package unix
+
+import (
+	"unsafe"
+)
+
+// ioctl itself should not be exposed directly, but additional get/set
+// functions for specific types are permissible.
+
+// IoctlSetInt performs an ioctl operation which sets an integer value
+// on fd, using the specified request number.
+func IoctlSetInt(fd int, req int, value int) error {
+	return ioctl(fd, req, uintptr(value))
+}
+
+// IoctlSetPointerInt performs an ioctl operation which sets an
+// integer value on fd, using the specified request number. The ioctl
+// argument is called with a pointer to the integer value, rather than
+// passing the integer value directly.
+func IoctlSetPointerInt(fd int, req int, value int) error {
+	v := int32(value)
+	return ioctlPtr(fd, req, unsafe.Pointer(&v))
+}
+
+// IoctlSetWinsize performs an ioctl on fd with a *Winsize argument.
+//
+// To change fd's window size, the req argument should be TIOCSWINSZ.
+func IoctlSetWinsize(fd int, req int, value *Winsize) error {
+	// TODO: if we get the chance, remove the req parameter and
+	// hardcode TIOCSWINSZ.
+	return ioctlPtr(fd, req, unsafe.Pointer(value))
+}
+
+// IoctlSetTermios performs an ioctl on fd with a *Termios.
+//
+// The req value will usually be TCSETA or TIOCSETA.
+func IoctlSetTermios(fd int, req int, value *Termios) error {
+	// TODO: if we get the chance, remove the req parameter.
+	return ioctlPtr(fd, req, unsafe.Pointer(value))
+}
+
+// IoctlGetInt performs an ioctl operation which gets an integer value
+// from fd, using the specified request number.
+//
+// A few ioctl requests use the return value as an output parameter;
+// for those, IoctlRetInt should be used instead of this function.
+func IoctlGetInt(fd int, req int) (int, error) {
+	var value int
+	err := ioctlPtr(fd, req, unsafe.Pointer(&value))
+	return value, err
+}
+
+func IoctlGetWinsize(fd int, req int) (*Winsize, error) {
+	var value Winsize
+	err := ioctlPtr(fd, req, unsafe.Pointer(&value))
+	return &value, err
+}
+
+func IoctlGetTermios(fd int, req int) (*Termios, error) {
+	var value Termios
+	err := ioctlPtr(fd, req, unsafe.Pointer(&value))
+	return &value, err
+}

unix/ioctl.go renamed to unix/ioctl_unsigned.go

@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build aix || darwin || dragonfly || freebsd || hurd || linux || netbsd || openbsd || solaris
-// +build aix darwin dragonfly freebsd hurd linux netbsd openbsd solaris
+//go:build darwin || dragonfly || freebsd || hurd || linux || netbsd || openbsd
+// +build darwin dragonfly freebsd hurd linux netbsd openbsd
 
 package unix
 

unix/ioctl_zos.go

@@ -17,14 +17,14 @@ import (
 
 // IoctlSetInt performs an ioctl operation which sets an integer value
 // on fd, using the specified request number.
-func IoctlSetInt(fd int, req uint, value int) error {
+func IoctlSetInt(fd int, req int, value int) error {
 	return ioctl(fd, req, uintptr(value))
 }
 
 // IoctlSetWinsize performs an ioctl on fd with a *Winsize argument.
 //
 // To change fd's window size, the req argument should be TIOCSWINSZ.
-func IoctlSetWinsize(fd int, req uint, value *Winsize) error {
+func IoctlSetWinsize(fd int, req int, value *Winsize) error {
 	// TODO: if we get the chance, remove the req parameter and
 	// hardcode TIOCSWINSZ.
 	return ioctlPtr(fd, req, unsafe.Pointer(value))
@@ -33,7 +33,7 @@ func IoctlSetWinsize(fd int, req uint, value *Winsize) error {
 // IoctlSetTermios performs an ioctl on fd with a *Termios.
 //
 // The req value is expected to be TCSETS, TCSETSW, or TCSETSF
-func IoctlSetTermios(fd int, req uint, value *Termios) error {
+func IoctlSetTermios(fd int, req int, value *Termios) error {
 	if (req != TCSETS) && (req != TCSETSW) && (req != TCSETSF) {
 		return ENOSYS
 	}
@@ -47,13 +47,13 @@ func IoctlSetTermios(fd int, req uint, value *Termios) error {
 //
 // A few ioctl requests use the return value as an output parameter;
 // for those, IoctlRetInt should be used instead of this function.
-func IoctlGetInt(fd int, req uint) (int, error) {
+func IoctlGetInt(fd int, req int) (int, error) {
 	var value int
 	err := ioctlPtr(fd, req, unsafe.Pointer(&value))
 	return value, err
 }
 
-func IoctlGetWinsize(fd int, req uint) (*Winsize, error) {
+func IoctlGetWinsize(fd int, req int) (*Winsize, error) {
 	var value Winsize
 	err := ioctlPtr(fd, req, unsafe.Pointer(&value))
 	return &value, err
@@ -62,7 +62,7 @@ func IoctlGetWinsize(fd int, req uint) (*Winsize, error) {
 // IoctlGetTermios performs an ioctl on fd with a *Termios.
 //
 // The req value is expected to be TCGETS
-func IoctlGetTermios(fd int, req uint) (*Termios, error) {
+func IoctlGetTermios(fd int, req int) (*Termios, error) {
 	var value Termios
 	if req != TCGETS {
 		return &value, ENOSYS

unix/syscall_aix.go

@@ -408,8 +408,8 @@ func (w WaitStatus) CoreDump() bool { return w&0x80 == 0x80 }
 
 func (w WaitStatus) TrapCause() int { return -1 }
 
-//sys	ioctl(fd int, req uint, arg uintptr) (err error)
-//sys	ioctlPtr(fd int, req uint, arg unsafe.Pointer) (err error) = ioctl
+//sys	ioctl(fd int, req int, arg uintptr) (err error)
+//sys	ioctlPtr(fd int, req int, arg unsafe.Pointer) (err error) = ioctl
 
 // fcntl must never be called with cmd=F_DUP2FD because it doesn't work on AIX
 // There is no way to create a custom fcntl and to keep //sys fcntl easily,

unix/syscall_solaris.go

@@ -545,24 +545,24 @@ func Minor(dev uint64) uint32 {
  * Expose the ioctl function
  */
 
-//sys	ioctlRet(fd int, req uint, arg uintptr) (ret int, err error) = libc.ioctl
-//sys	ioctlPtrRet(fd int, req uint, arg unsafe.Pointer) (ret int, err error) = libc.ioctl
+//sys	ioctlRet(fd int, req int, arg uintptr) (ret int, err error) = libc.ioctl
+//sys	ioctlPtrRet(fd int, req int, arg unsafe.Pointer) (ret int, err error) = libc.ioctl
 
-func ioctl(fd int, req uint, arg uintptr) (err error) {
+func ioctl(fd int, req int, arg uintptr) (err error) {
 	_, err = ioctlRet(fd, req, arg)
 	return err
 }
 
-func ioctlPtr(fd int, req uint, arg unsafe.Pointer) (err error) {
+func ioctlPtr(fd int, req int, arg unsafe.Pointer) (err error) {
 	_, err = ioctlPtrRet(fd, req, arg)
 	return err
 }
 
-func IoctlSetTermio(fd int, req uint, value *Termio) error {
+func IoctlSetTermio(fd int, req int, value *Termio) error {
 	return ioctlPtr(fd, req, unsafe.Pointer(value))
 }
 
-func IoctlGetTermio(fd int, req uint) (*Termio, error) {
+func IoctlGetTermio(fd int, req int) (*Termio, error) {
 	var value Termio
 	err := ioctlPtr(fd, req, unsafe.Pointer(&value))
 	return &value, err
@@ -1079,11 +1079,11 @@ func Getmsg(fd int, cl []byte, data []byte) (retCl []byte, retData []byte, flags
 	return retCl, retData, flags, nil
 }
 
-func IoctlSetIntRetInt(fd int, req uint, arg int) (int, error) {
+func IoctlSetIntRetInt(fd int, req int, arg int) (int, error) {
 	return ioctlRet(fd, req, uintptr(arg))
 }
 
-func IoctlSetString(fd int, req uint, val string) error {
+func IoctlSetString(fd int, req int, val string) error {
 	bs := make([]byte, len(val)+1)
 	copy(bs[:len(bs)-1], val)
 	err := ioctlPtr(fd, req, unsafe.Pointer(&bs[0]))
@@ -1119,7 +1119,7 @@ func (l *Lifreq) GetLifruUint() uint {
 	return *(*uint)(unsafe.Pointer(&l.Lifru[0]))
 }
 
-func IoctlLifreq(fd int, req uint, l *Lifreq) error {
+func IoctlLifreq(fd int, req int, l *Lifreq) error {
 	return ioctlPtr(fd, req, unsafe.Pointer(l))
 }
 
@@ -1130,6 +1130,6 @@ func (s *Strioctl) SetInt(i int) {
 	s.Dp = (*int8)(unsafe.Pointer(&i))
 }
 
-func IoctlSetStrioctlRetInt(fd int, req uint, s *Strioctl) (int, error) {
+func IoctlSetStrioctlRetInt(fd int, req int, s *Strioctl) (int, error) {
 	return ioctlPtrRet(fd, req, unsafe.Pointer(s))
 }

unix/syscall_solaris_test.go

@@ -405,17 +405,13 @@ func TestLifreqGetMTU(t *testing.T) {
 	if err != nil {
 		t.Fatalf("could not open udp socket: %v", err)
 	}
-	// SIOCGLIFMTU is negative which confuses the compiler if used inline:
-	// Using "unix.IoctlLifreq(ip_fd, unix.SIOCGLIFMTU, &l)" results in
-	// "constant -1065850502 overflows uint"
-	reqnum := int(unix.SIOCGLIFMTU)
 	var l unix.Lifreq
 	for link, mtu := range tc {
 		err = l.SetName(link)
 		if err != nil {
 			t.Fatalf("Lifreq.SetName(%q) failed: %v", link, err)
 		}
-		if err = unix.IoctlLifreq(ip_fd, uint(reqnum), &l); err != nil {
+		if err = unix.IoctlLifreq(ip_fd, unix.SIOCGLIFMTU, &l); err != nil {
 			t.Fatalf("unable to SIOCGLIFMTU: %v", err)
 		}
 		m := l.GetLifruUint()

unix/syscall_zos_s390x.go

@@ -212,8 +212,8 @@ func (cmsg *Cmsghdr) SetLen(length int) {
 //sys	sendmsg(s int, msg *Msghdr, flags int) (n int, err error) = SYS___SENDMSG_A
 //sys   mmap(addr uintptr, length uintptr, prot int, flag int, fd int, pos int64) (ret uintptr, err error) = SYS_MMAP
 //sys   munmap(addr uintptr, length uintptr) (err error) = SYS_MUNMAP
-//sys   ioctl(fd int, req uint, arg uintptr) (err error) = SYS_IOCTL
-//sys   ioctlPtr(fd int, req uint, arg unsafe.Pointer) (err error) = SYS_IOCTL
+//sys   ioctl(fd int, req int, arg uintptr) (err error) = SYS_IOCTL
+//sys   ioctlPtr(fd int, req int, arg unsafe.Pointer) (err error) = SYS_IOCTL
 
 //sys   Access(path string, mode uint32) (err error) = SYS___ACCESS_A
 //sys   Chdir(path string) (err error) = SYS___CHDIR_A