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@@ -0,0 +1,139 @@
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+package pty
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+
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+/* based on:
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+http://src.illumos.org/source/xref/illumos-gate/usr/src/lib/libc/port/gen/pt.c
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+*/
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+
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+import (
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+ "errors"
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+ "golang.org/x/sys/unix"
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+ "os"
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+ "strconv"
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+ "syscall"
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+ "unsafe"
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+)
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+
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+const NODEV = ^uint64(0)
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+
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+func open() (pty, tty *os.File, err error) {
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+ masterfd, err := syscall.Open("/dev/ptmx", syscall.O_RDWR|unix.O_NOCTTY, 0)
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+ //masterfd, err := syscall.Open("/dev/ptmx", syscall.O_RDWR|syscall.O_CLOEXEC|unix.O_NOCTTY, 0)
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+ if err != nil {
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+ return nil, nil, err
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+ }
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+ p := os.NewFile(uintptr(masterfd), "/dev/ptmx")
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+
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+ sname, err := ptsname(p)
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+ if err != nil {
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+ return nil, nil, err
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+ }
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+
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+ err = grantpt(p)
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+ if err != nil {
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+ return nil, nil, err
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+ }
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+
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+ err = unlockpt(p)
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+ if err != nil {
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+ return nil, nil, err
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+ }
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+
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+ slavefd, err := syscall.Open(sname, os.O_RDWR|unix.O_NOCTTY, 0)
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+ if err != nil {
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+ return nil, nil, err
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+ }
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+ t := os.NewFile(uintptr(slavefd), sname)
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+
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+ // pushing terminal driver STREAMS modules as per pts(7)
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+ for _, mod := range([]string{"ptem", "ldterm", "ttcompat"}) {
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+ err = streams_push(t, mod)
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+ if err != nil {
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+ return nil, nil, err
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+ }
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+ }
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+
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+ return p, t, nil
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+}
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+
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+func minor(x uint64) uint64 {
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+ return x & 0377
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+}
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+
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+func ptsdev(fd uintptr) uint64 {
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+ istr := strioctl{ISPTM, 0, 0, nil}
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+ err := ioctl(fd, I_STR, uintptr(unsafe.Pointer(&istr)))
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+ if err != nil {
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+ return NODEV
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+ }
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+ var status unix.Stat_t
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+ err = unix.Fstat(int(fd), &status)
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+ if err != nil {
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+ return NODEV
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+ }
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+ return uint64(minor(status.Rdev))
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+}
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+
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+func ptsname(f *os.File) (string, error) {
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+ dev := ptsdev(f.Fd())
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+ if dev == NODEV {
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+ return "", errors.New("not a master pty")
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+ }
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+ fn := "/dev/pts/" + strconv.FormatInt(int64(dev), 10)
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+ // access(2) creates the slave device (if the pty exists)
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+ // F_OK == 0 (unistd.h)
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+ err := unix.Access(fn, 0)
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+ if err != nil {
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+ return "", err
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+ }
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+ return fn, nil
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+}
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+
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+type pt_own struct {
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+ pto_ruid int32
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+ pto_rgid int32
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+}
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+
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+func grantpt(f *os.File) error {
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+ if ptsdev(f.Fd()) == NODEV {
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+ return errors.New("not a master pty")
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+ }
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+ var pto pt_own
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+ pto.pto_ruid = int32(os.Getuid())
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+ // XXX should first attempt to get gid of DEFAULT_TTY_GROUP="tty"
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+ pto.pto_rgid = int32(os.Getgid())
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+ var istr strioctl
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+ istr.ic_cmd = OWNERPT
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+ istr.ic_timout = 0
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+ istr.ic_len = int32(unsafe.Sizeof(istr))
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+ istr.ic_dp = unsafe.Pointer(&pto)
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+ err := ioctl(f.Fd(), I_STR, uintptr(unsafe.Pointer(&istr)))
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+ if err != nil {
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+ return errors.New("access denied")
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+ }
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+ return nil
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+}
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+
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+func unlockpt(f *os.File) error {
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+ istr := strioctl{UNLKPT, 0, 0, nil}
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+ return ioctl(f.Fd(), I_STR, uintptr(unsafe.Pointer(&istr)))
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+}
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+
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+// push STREAMS modules if not already done so
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+func streams_push(f *os.File, mod string) error {
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+ var err error
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+ buf := []byte(mod)
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+ // XXX I_FIND is not returning an error when the module
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+ // is already pushed even though truss reports a return
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+ // value of 1. A bug in the Go Solaris syscall interface?
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+ // XXX without this we are at risk of the issue
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+ // https://www.illumos.org/issues/9042
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+ // but since we are not using libc or XPG4.2, we should not be
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+ // double-pushing modules
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+
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+ err = ioctl(f.Fd(), I_FIND, uintptr(unsafe.Pointer(&buf[0])))
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+ if err != nil {
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+ return nil
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+ }
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+ err = ioctl(f.Fd(), I_PUSH, uintptr(unsafe.Pointer(&buf[0])))
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+ return err
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+}
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