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/*
 * xdmshell - simple program for running xdm from login
 *
 *
Copyright 1988, 1998  The Open Group

Permission to use, copy, modify, distribute, and sell this software and its
documentation for any purpose is hereby granted without fee, provided that
the above copyright notice appear in all copies and that both that
copyright notice and this permission notice appear in supporting
documentation.

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Except as contained in this notice, the name of The Open Group shall not be
used in advertising or otherwise to promote the sale, use or other dealings
in this Software without prior written authorization from The Open Group.
 * *
 * Author:  Jim Fulton, MIT X Consortium
 *
 * This program should probably be setuid to root.
 *
 * WARNING:  Make sure that you tailor your Xresources file to have a
 * way of invoking the abort-display() action.  Otherwise, you won't be able
 * bring down X when you are finished.
 */


#include <stdio.h>
#include "dm.h"
#include <errno.h>
#include <unistd.h>

#ifndef BINDIR
# define BINDIR "/usr/bin/X11"
#endif

/*
 * HP-UX does have vfork, but A/UX doesn't
 */
#ifdef HAVE_WORKING_VFORK /* autoconf's preferred name */
# define HAS_VFORK
#endif

#ifndef HAS_VFORK
# define vfork() fork()
#endif

static char *ProgramName;

static int exec_args (
    char *filename,
    char **args)
{
    pid_t pid;
    waitType status;

    if (!filename) return -1;

    if (filename[0] != '/') {
	fprintf (stderr,
	       "%s:  attempt to execute program with relative pathname:  %s\n",
		 ProgramName, filename);
	return -1;
    }

    if (access (filename, X_OK) != 0) return -1;

    switch (pid = vfork ()) {
      case -1:						/* error */
	return -1;
      case 0:    					/* child */
	execv (filename, args);
	_exit (1);
	/* NOTREACHED */
      default:						/* parent */
	while (wait (&status) != pid) ;
    }
    return waitCode (status);
}

#if defined(sun)
static int exec_one_arg (
    char    *filename,
    char    *arg)
{
    char    *argv[3];

    argv[0] = filename;
    argv[1] = arg;
    argv[2] = NULL;
    return exec_args (filename, argv);
}
#endif

int
main (
    int argc,
    char *argv[])
{
    int ttyfd;
    char cmdbuf[256];
    char *args[10];

    ProgramName = argv[0];

    if (argc > 1) {
	fprintf (stderr, "usage:  %s\r\n", ProgramName);
	exit (1);
    }

    ttyfd = open ("/dev/tty", O_RDWR, 0);
    if (ttyfd < 3) {			/* stdin = 0, stdout = 1, stderr = 2 */
	fprintf (stderr,
		 "%s:  must be run directly from the console.\r\n",
		 ProgramName);
	exit (1);
    }
    (void) close (ttyfd);

    /* make xdm run in a non-setuid environment */
    if (setuid (geteuid()) == -1) {
	fprintf(stderr, "%s: cannot setuid (error %d, %s)\r\n",
		ProgramName, errno, strerror(errno));
	exit(1);
    }

    /*
     * exec /usr/bin/X11/xdm -nodaemon -udpPort 0
     */
    strcpy (cmdbuf, BINDIR);
    strcat (cmdbuf, "/xdm");
    args[0] = cmdbuf;
    args[1] = "-nodaemon";
    args[2] = "-udpPort";
    args[3] = "0";
    args[4] = NULL;
    if (exec_args (cmdbuf, args) == -1) {
	fprintf (stderr, "%s:  unable to execute %s (error %d, %s)\r\n",
		 ProgramName, cmdbuf, errno, strerror(errno));
	exit (1);
    }

#ifdef sun
    strcpy (cmdbuf, BINDIR);
    strcat (cmdbuf, "/kbd_mode");
    (void) exec_one_arg (cmdbuf, "-a");
#endif

    exit (0);
    /*NOTREACHED*/
}