kpty.cpp

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/*

   This file is part of the KDE libraries
   Copyright (C) 2002, 2013 Waldo Bastian <bastian@kde.org>
   Copyright (C) 2002-2003,2007 Oswald Buddenhagen <ossi@kde.org>

    Rewritten for QT4 by e_k <e_k at users.sourceforge.net>, Copyright (C)2008

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License as published by the Free Software Foundation; either
   version 2 of the License, or (at your option) any later version.

   This library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public License
   along with this library; see the file COPYING.LIB.  If not, write to
   the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
   Boston, MA 02110-1301, USA.
*/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "unix/kpty_p.h"

#ifdef __sgi
#define __svr4__
#endif

#ifdef __osf__
#define _OSF_SOURCE
#include <float.h>
#endif

#ifdef _AIX
#define _ALL_SOURCE
#endif

// __USE_XOPEN isn't defined by default in ICC
// (needed for ptsname(), grantpt() and unlockpt())
#ifdef __INTEL_COMPILER
#  ifndef __USE_XOPEN
#    define __USE_XOPEN
#  endif
#endif

#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/param.h>

#include <errno.h>
#include <fcntl.h>
#include <time.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <grp.h>

#ifdef Q_OS_MAC
# include <util.h>
#else
# if defined(HAVE_PTY_H)
#  include <pty.h>
# endif
# ifdef HAVE_LIBUTIL_H
#  include <libutil.h>
# elif defined(HAVE_UTIL_H)
#  include <util.h>
# endif
#endif

/*
#ifdef HAVE_UTEMPTER
extern "C" {
# include <utempter.h>
}
#else
# include <utmp.h>
# ifdef HAVE_UTMPX
#  include <utmpx.h>
# endif
# if !defined(_PATH_UTMPX) && defined(_UTMPX_FILE)
#  define _PATH_UTMPX _UTMPX_FILE
# endif
# if !defined(_PATH_WTMPX) && defined(_WTMPX_FILE)
#  define _PATH_WTMPX _WTMPX_FILE
# endif
#endif
*/

/* for HP-UX (some versions) the extern C is needed, and for other
   platforms it doesn't hurt */
extern "C" {
#include <termios.h>
#if defined(HAVE_TERMIO_H)
# include <termio.h> // struct winsize on some systems
#endif
}

#if defined (_HPUX_SOURCE)
# define _TERMIOS_INCLUDED
# include <bsdtty.h>
#endif

#ifdef HAVE_SYS_STROPTS_H
# include <sys/stropts.h> // Defines I_PUSH
# define _NEW_TTY_CTRL
#endif

#if defined (__FreeBSD__) || defined (__NetBSD__) || defined (__OpenBSD__) || defined (__bsdi__) || defined(__APPLE__) || defined (__DragonFly__)
# define _tcgetattr(fd, ttmode) ioctl(fd, TIOCGETA, (char *)ttmode)
#else
# if defined(_HPUX_SOURCE) || defined(__Lynx__) || defined (__CYGWIN__)
#  define _tcgetattr(fd, ttmode) tcgetattr(fd, ttmode)
# else
#  define _tcgetattr(fd, ttmode) ioctl(fd, TCGETS, (char *)ttmode)
# endif
#endif

#if defined (__FreeBSD__) || defined (__NetBSD__) || defined (__OpenBSD__) || defined (__bsdi__) || defined(__APPLE__) || defined (__DragonFly__)
# define _tcsetattr(fd, ttmode) ioctl(fd, TIOCSETA, (char *)ttmode)
#else
# if defined(_HPUX_SOURCE) || defined(__CYGWIN__)
#  define _tcsetattr(fd, ttmode) tcsetattr(fd, TCSANOW, ttmode)
# else
#  define _tcsetattr(fd, ttmode) ioctl(fd, TCSETS, (char *)ttmode)
# endif
#endif

#include <QtCore>

// not defined on HP-UX for example
#ifndef CTRL
# define CTRL(x) ((x) & 037)
#endif

#define TTY_GROUP "tty"

///////////////////////
// private functions //
///////////////////////

//////////////////
// private data //
//////////////////

KPtyPrivate::KPtyPrivate(KPty* parent) :
    masterFd(-1), slaveFd(-1), ownMaster(true), q_ptr(parent)
{
}

KPtyPrivate::KPtyPrivate(KPty *parent, int _masterFd, int _slaveFd):
    masterFd(_masterFd), slaveFd(_slaveFd), ownMaster(true), q_ptr(parent)
{
}


KPtyPrivate::~KPtyPrivate()
{
}

#ifndef HAVE_OPENPTY
bool KPtyPrivate::chownpty(bool)
{
//    return !QProcess::execute(KStandardDirs::findExe("kgrantpty"),
//        QStringList() << (grant?"--grant":"--revoke") << QString::number(masterFd));
    return true;
}
#endif

/////////////////////////////
// public member functions //
/////////////////////////////

KPty::KPty() :
    d_ptr(new KPtyPrivate(this))
{
}

KPty::KPty(int masterFd, int slaveFd) :
    d_ptr(new KPtyPrivate(this, masterFd, slaveFd))
{
}

KPty::KPty(KPtyPrivate *d) :
    d_ptr(d)
{
    d_ptr->q_ptr = this;
}

KPty::~KPty()
{
    close();
    delete d_ptr;
}

bool KPty::open()
{
  Q_D(KPty);

  if (d->masterFd >= 0) {
      return true;
  }

  d->ownMaster = true;

  QByteArray ptyName;

  // Find a master pty that we can open ////////////////////////////////

  // Because not all the pty animals are created equal, they want to
  // be opened by several different methods.

  // We try, as we know them, one by one.

#ifdef HAVE_OPENPTY

  char ptsn[PATH_MAX];
  if (::openpty( &d->masterFd, &d->slaveFd, ptsn, 0, 0))
  {
    d->masterFd = -1;
    d->slaveFd = -1;
    qWarning() << "Can't open a pseudo teletype";
    return false;
  }
  d->ttyName = ptsn;

#else

#ifdef HAVE__GETPTY // irix

  char *ptsn = _getpty(&d->masterFd, O_RDWR|O_NOCTTY, S_IRUSR|S_IWUSR, 0);
  if (ptsn) {
    d->ttyName = ptsn;
    goto grantedpt;
  }

#elif defined(HAVE_PTSNAME) || defined(TIOCGPTN)

#ifdef HAVE_POSIX_OPENPT
  d->masterFd = ::posix_openpt(O_RDWR|O_NOCTTY);
#elif defined(HAVE_GETPT)
  d->masterFd = ::getpt();
#elif defined(PTM_DEVICE)
  d->masterFd = ::open(PTM_DEVICE, O_RDWR|O_NOCTTY);
#else
# error No method to open a PTY master detected.
#endif
  if (d->masterFd >= 0)
  {
#ifdef HAVE_PTSNAME
    char *ptsn = ptsname(d->masterFd);
    if (ptsn) {
        d->ttyName = ptsn;
#else
    int ptyno;
    if (!ioctl(d->masterFd, TIOCGPTN, &ptyno)) {
        char buf[32];
        sprintf(buf, "/dev/pts/%d", ptyno);
        d->ttyName = buf;
#endif
#ifdef HAVE_GRANTPT
        if (!grantpt(d->masterFd))
           goto grantedpt;
#else
        goto gotpty;
#endif
    }
    ::close(d->masterFd);
    d->masterFd = -1;
  }
#endif // HAVE_PTSNAME || TIOCGPTN

  // Linux device names, FIXME: Trouble on other systems?
  for (const char* s3 = "pqrstuvwxyzabcde"; *s3; s3++)
  {
    for (const char* s4 = "0123456789abcdef"; *s4; s4++)
    {
      ptyName = QString().sprintf("/dev/pty%c%c", *s3, *s4).toAscii();
      d->ttyName = QString().sprintf("/dev/tty%c%c", *s3, *s4).toAscii();

      d->masterFd = ::open(ptyName.data(), O_RDWR);
      if (d->masterFd >= 0)
      {
#ifdef Q_OS_SOLARIS
        /* Need to check the process group of the pty.
         * If it exists, then the slave pty is in use,
         * and we need to get another one.
         */
        int pgrp_rtn;
        if (ioctl(d->masterFd, TIOCGPGRP, &pgrp_rtn) == 0 || errno != EIO) {
          ::close(d->masterFd);
          d->masterFd = -1;
          continue;
        }
#endif /* Q_OS_SOLARIS */
        if (!access(d->ttyName.data(),R_OK|W_OK)) // checks availability based on permission bits
        {
          if (!geteuid())
          {
            struct group* p = getgrnam(TTY_GROUP);
            if (!p)
              p = getgrnam("wheel");
            gid_t gid = p ? p->gr_gid : getgid ();

     if (!chown(d->ttyName.data(), getuid(), gid)) {
      chmod(d->ttyName.data(), S_IRUSR|S_IWUSR|S_IWGRP);
     }
    }
    goto gotpty;
  }
  ::close(d->masterFd);
  d->masterFd = -1;
    }
   }
  }

  qWarning() << "Can't open a pseudo teletype";
  return false;

 gotpty:
  struct stat st;
  if (stat(d->ttyName.data(), &st))
    return false; // this just cannot happen ... *cough*  Yeah right, I just
                  // had it happen when pty #349 was allocated.  I guess
                  // there was some sort of leak?  I only had a few open.
  if (((st.st_uid != getuid()) ||
       (st.st_mode & (S_IRGRP|S_IXGRP|S_IROTH|S_IWOTH|S_IXOTH))) &&
      !d->chownpty(true))
  {
    qWarning()
      << "chownpty failed for device " << ptyName << "::" << d->ttyName
      << "\nThis means the communication can be eavesdropped." << endl;
  }

#if defined(HAVE_GRANTPT) || defined(HAVE__GETPTY)
 grantedpt:
#endif

#ifdef HAVE_REVOKE
  revoke(d->ttyName.data());
#endif

#ifdef HAVE_UNLOCKPT
  unlockpt(d->masterFd);
#elif defined(TIOCSPTLCK)
  int flag = 0;
  ioctl(d->masterFd, TIOCSPTLCK, &flag);
#endif

  d->slaveFd = ::open(d->ttyName.data(), O_RDWR | O_NOCTTY);
  if (d->slaveFd < 0)
  {
    qWarning() << "Can't open slave pseudo teletype";
    ::close(d->masterFd);
    d->masterFd = -1;
    return false;
  }

#if (defined(__svr4__) || defined(__sgi__))
  // Solaris
  ioctl(d->slaveFd, I_PUSH, "ptem");
  ioctl(d->slaveFd, I_PUSH, "ldterm");
#endif

#endif /* HAVE_OPENPTY */
  fcntl(d->masterFd, F_SETFD, FD_CLOEXEC);
  fcntl(d->slaveFd, F_SETFD, FD_CLOEXEC);

  struct ::termios t;
  tcGetAttr(&t);
  t.c_lflag &= ~ECHOCTL;
  tcSetAttr(&t);
  return true;
}

void KPty::closeSlave()
{
    Q_D(KPty);

    if (d->slaveFd < 0)
        return;
    ::close(d->slaveFd);
    d->slaveFd = -1;
}

void KPty::close()
{
   Q_D(KPty);

   if (d->masterFd < 0)
      return;
   closeSlave();
   if (d->ownMaster) {
#ifndef HAVE_OPENPTY
   // don't bother resetting unix98 pty, it will go away after closing master anyway.
   if (memcmp(d->ttyName.data(), "/dev/pts/", 9)) {
      if (!geteuid()) {
         struct stat st;
         if (!stat(d->ttyName.data(), &st)) {
            if (!chown(d->ttyName.data(), 0, st.st_gid == getgid() ? 0 : -1)) {
              chmod(d->ttyName.data(), S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH);
            }
         }
      } else {
         fcntl(d->masterFd, F_SETFD, 0);
         d->chownpty(false);
      }
   }
   #endif
   }
   ::close(d->masterFd);
   d->masterFd = -1;
}

// XXX Supposedly, tc[gs]etattr do not work with the master on Solaris.
// Please verify.

bool KPty::tcGetAttr(struct ::termios *ttmode) const
{
    Q_D(const KPty);

    return _tcgetattr(d->masterFd, ttmode) == 0;
}

bool KPty::tcSetAttr(struct ::termios *ttmode)
{
    Q_D(KPty);

    return _tcsetattr(d->masterFd, ttmode) == 0;
}

bool KPty::setWinSize(int lines, int columns)
{
    Q_D(KPty);

    struct winsize winSize;
    memset(&winSize, 0, sizeof(winSize));
    winSize.ws_row = (unsigned short)lines;
    winSize.ws_col = (unsigned short)columns;
    return ioctl(d->masterFd, TIOCSWINSZ, (char *)&winSize) == 0;
}

bool KPty::setEcho(bool echo)
{
    struct ::termios ttmode;
    if (!tcGetAttr(&ttmode))
        return false;
    if (!echo)
        ttmode.c_lflag &= ~ECHO;
    else
        ttmode.c_lflag |= ECHO;
    return tcSetAttr(&ttmode);
}

const char *KPty::ttyName() const
{
    Q_D(const KPty);

    return d->ttyName.data();
}

int KPty::masterFd() const
{
    Q_D(const KPty);

    return d->masterFd;
}

int KPty::slaveFd() const
{
    Q_D(const KPty);

    return d->slaveFd;
}