port/gen/pt.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*  Copyright (c) 1988 AT&T */
/*    All Rights Reserved   */

#pragma ident   "%Z%%M% %I% %E% SMI"

#pragma weak _ptsname = ptsname
#pragma weak _grantpt = grantpt
#pragma weak _unlockpt = unlockpt

#include "lint.h"
#include "libc.h"
#include "mtlib.h"
#include <sys/types.h>
#include <signal.h>
#include <sys/param.h>
#include <sys/mkdev.h>
#include <sys/stream.h>
#include <sys/stropts.h>
#include <sys/wait.h>
#include <sys/signal.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/ptms.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <wait.h>
#include <spawn.h>
#include <grp.h>
#include "tsd.h"

#define PTSNAME "/dev/pts/"     /* slave name */
#define PTLEN   32          /* slave name length */
#define DEFAULT_TTY_GROUP   "tty"   /* slave device group owner */

static void itoa(int, char *);

/*
 *  Check that fd argument is a file descriptor of an opened master.
 *  Do this by sending an ISPTM ioctl message down stream. Ioctl()
 *  will fail if:(1) fd is not a valid file descriptor.(2) the file
 *  represented by fd does not understand ISPTM(not a master device).
 *  If we have a valid master, get its minor number via fstat().
 *  Concatenate it to PTSNAME and return it as the name of the slave
 *  device.
 */
static dev_t
ptsdev(int fd)
{
    struct stat64 status;
    struct strioctl istr;

    istr.ic_cmd = ISPTM;
    istr.ic_len = 0;
    istr.ic_timout = 0;
    istr.ic_dp = NULL;

    if (ioctl(fd, I_STR, &istr) < 0 || fstat64(fd, &status) < 0)
        return (NODEV);

    return (minor(status.st_rdev));
}

char *
ptsname(int fd)
{
    dev_t dev;
    char *sname;

    if ((dev = ptsdev(fd)) == NODEV)
        return (NULL);

    sname = tsdalloc(_T_PTSNAME, PTLEN, NULL);
    if (sname == NULL)
        return (NULL);
    (void) strcpy(sname, PTSNAME);
    itoa(dev, sname + strlen(PTSNAME));

    /*
     * This lookup will create the /dev/pts node (if the corresponding
     * pty exists.
     */
    if (access(sname, F_OK) ==  0)
        return (sname);

    return (NULL);
}

/*
 * Send an ioctl down to the master device requesting the
 * master/slave pair be unlocked.
 */
int
unlockpt(int fd)
{
    struct strioctl istr;

    istr.ic_cmd = UNLKPT;
    istr.ic_len = 0;
    istr.ic_timout = 0;
    istr.ic_dp = NULL;

    if (ioctl(fd, I_STR, &istr) < 0)
        return (-1);

    return (0);
}

int
grantpt(int fd)
{
    struct strioctl istr;
    pt_own_t pto;
    struct group *gr_name;

    /* validate the file descriptor before proceeding */
    if (ptsdev(fd) == NODEV)
        return (-1);

    pto.pto_ruid = getuid();

    gr_name = getgrnam(DEFAULT_TTY_GROUP);
    if (gr_name)
        pto.pto_rgid = gr_name->gr_gid;
    else
        pto.pto_rgid = getgid();

    istr.ic_cmd = OWNERPT;
    istr.ic_len = sizeof (pt_own_t);
    istr.ic_timout = 0;
    istr.ic_dp = (char *)&pto;

    if (ioctl(fd, I_STR, &istr) != 0) {
        errno = EACCES;
        return (-1);
    }

    return (0);
}

/*
 * Send an ioctl down to the master device requesting the master/slave pair
 * be assigned to the given zone.
 */
int
zonept(int fd, zoneid_t zoneid)
{
    struct strioctl istr;

    istr.ic_cmd = ZONEPT;
    istr.ic_len = sizeof (zoneid);
    istr.ic_timout = 0;
    istr.ic_dp = (char *)&zoneid;

    if (ioctl(fd, I_STR, &istr) != 0) {
        return (-1);
    }
    return (0);
}


static void
itoa(int i, char *ptr)
{
    int dig = 0;
    int tempi;

    tempi = i;
    do {
        dig++;
        tempi /= 10;
    } while (tempi);

    ptr += dig;
    *ptr = '\0';
    while (--dig >= 0) {
        *(--ptr) = i % 10 + '0';
        i /= 10;
    }
}


/*
 * added for SUSv3 standard
 *
 * Open a pseudo-terminal device.  External interface.
 */

int
posix_openpt(int oflag)
{
    return (open("/dev/ptmx", oflag));
}