xenocara/xserver/os/utils.c

/*

Copyright 1987, 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.

Copyright 1987 by Digital Equipment Corporation, Maynard, Massachusetts,
Copyright 1994 Quarterdeck Office Systems.

                        All Rights Reserved

Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted,
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in
supporting documentation, and that the names of Digital and
Quarterdeck not be used in advertising or publicity pertaining to
distribution of the software without specific, written prior
permission.

DIGITAL AND QUARTERDECK DISCLAIM ALL WARRANTIES WITH REGARD TO THIS
SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS, IN NO EVENT SHALL DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT
OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE
OR PERFORMANCE OF THIS SOFTWARE.

*/

#ifdef HAVE_DIX_CONFIG_H
#include <dix-config.h>
#endif

#ifdef __CYGWIN__
#include <stdlib.h>
#include <signal.h>
/*
   Sigh... We really need a prototype for this to know it is stdcall,
   but #include-ing <windows.h> here is not a good idea...
*/
__stdcall unsigned long GetTickCount(void);
#endif

#if defined(WIN32) && !defined(__CYGWIN__)
#include <X11/Xwinsock.h>
#endif
#include <X11/Xos.h>
#include <stdio.h>
#include <time.h>
#if !defined(WIN32) || !defined(__MINGW32__)
#include <sys/time.h>
#include <sys/resource.h>
#endif
#include "misc.h"
#include <X11/X.h>
#define XSERV_t
#define TRANS_SERVER
#define TRANS_REOPEN
#include <X11/Xtrans/Xtrans.h>
#include "input.h"
#include "dixfont.h"
#include "osdep.h"
#include "extension.h"
#ifdef X_POSIX_C_SOURCE
#define _POSIX_C_SOURCE X_POSIX_C_SOURCE
#include <signal.h>
#undef _POSIX_C_SOURCE
#else
#if defined(_POSIX_SOURCE)
#include <signal.h>
#else
#define _POSIX_SOURCE
#include <signal.h>
#undef _POSIX_SOURCE
#endif
#endif
#ifndef WIN32
#include <sys/wait.h>
#endif
#if !defined(SYSV) && !defined(WIN32)
#include <sys/resource.h>
#endif
#include <sys/stat.h>
#include <ctype.h>              /* for isspace */
#include <stdarg.h>

#include <stdlib.h>             /* for malloc() */

#if defined(TCPCONN) || defined(STREAMSCONN)
#ifndef WIN32
#include <netdb.h>
#endif
#endif

#include "opaque.h"

#include "dixstruct.h"

#include "xkbsrv.h"

#include "picture.h"

Bool noTestExtensions;

#ifdef COMPOSITE
Bool noCompositeExtension = FALSE;
#endif

#ifdef DAMAGE
Bool noDamageExtension = FALSE;
#endif
#ifdef DBE
Bool noDbeExtension = FALSE;
#endif
#ifdef DPMSExtension
Bool noDPMSExtension = FALSE;
#endif
#ifdef GLXEXT
Bool noGlxExtension = FALSE;
Bool noGlxVisualInit = FALSE;
#endif
#ifdef SCREENSAVER
Bool noScreenSaverExtension = FALSE;
#endif
#ifdef MITSHM
Bool noMITShmExtension = FALSE;
#endif
#ifdef RANDR
Bool noRRExtension = FALSE;
#endif
Bool noRenderExtension = FALSE;

#ifdef XCSECURITY
Bool noSecurityExtension = FALSE;
#endif
#ifdef RES
Bool noResExtension = FALSE;
#endif
#ifdef XF86BIGFONT
Bool noXFree86BigfontExtension = FALSE;
#endif
#ifdef XFreeXDGA
Bool noXFree86DGAExtension = FALSE;
#endif
#ifdef XF86DRI
Bool noXFree86DRIExtension = FALSE;
#endif
#ifdef XF86VIDMODE
Bool noXFree86VidModeExtension = FALSE;
#endif
#ifdef XFIXES
Bool noXFixesExtension = FALSE;
#endif
#ifdef PANORAMIX
/* Xinerama is disabled by default unless enabled via +xinerama */
Bool noPanoramiXExtension = TRUE;
#endif
#ifdef XSELINUX
Bool noSELinuxExtension = FALSE;
int selinuxEnforcingState = SELINUX_MODE_DEFAULT;
#endif
#ifdef XV
Bool noXvExtension = FALSE;
#endif
#ifdef DRI2
Bool noDRI2Extension = FALSE;
#endif

Bool noGEExtension = FALSE;

#define X_INCLUDE_NETDB_H
#include <X11/Xos_r.h>

#include <errno.h>

Bool CoreDump;

#ifdef PANORAMIX
Bool PanoramiXExtensionDisabledHack = FALSE;
#endif

int auditTrailLevel = 1;

char *SeatId = NULL;

#if defined(SVR4) || defined(__linux__) || defined(CSRG_BASED)
#define HAS_SAVED_IDS_AND_SETEUID
#endif

OsSigHandlerPtr
OsSignal(int sig, OsSigHandlerPtr handler)
{
    struct sigaction act, oact;

    sigemptyset(&act.sa_mask);
    if (handler != SIG_IGN)
        sigaddset(&act.sa_mask, sig);
    act.sa_flags = 0;
    act.sa_handler = handler;
    if (sigaction(sig, &act, &oact))
        perror("sigaction");
    return oact.sa_handler;
}

/*
 * Explicit support for a server lock file like the ones used for UUCP.
 * For architectures with virtual terminals that can run more than one
 * server at a time.  This keeps the servers from stomping on each other
 * if the user forgets to give them different display numbers.
 */
#define LOCK_DIR "/tmp"
#define LOCK_TMP_PREFIX "/.tX"
#define LOCK_PREFIX "/.X"
#define LOCK_SUFFIX "-lock"

static Bool StillLocking = FALSE;
static char LockFile[PATH_MAX];
static Bool nolock = FALSE;

/*
 * LockServer --
 *      Check if the server lock file exists.  If so, check if the PID
 *      contained inside is valid.  If so, then die.  Otherwise, create
 *      the lock file containing the PID.
 */
void
LockServer(void)
{
    char tmp[PATH_MAX], pid_str[12];
    int lfd, i, haslock, l_pid, t;
    const char *tmppath = LOCK_DIR;
    int len;
    char port[20];

    if (nolock)
        return;
    /*
     * Path names
     */
    snprintf(port, sizeof(port), "%d", atoi(display));
    len = strlen(LOCK_PREFIX) > strlen(LOCK_TMP_PREFIX) ? strlen(LOCK_PREFIX) :
        strlen(LOCK_TMP_PREFIX);
    len += strlen(tmppath) + strlen(port) + strlen(LOCK_SUFFIX) + 1;
    if (len > sizeof(LockFile))
        FatalError("Display name `%s' is too long\n", port);
    (void) snprintf(tmp, sizeof(tmp),
                    "%s" LOCK_TMP_PREFIX "%s" LOCK_SUFFIX, tmppath, port);
    (void) snprintf(LockFile, sizeof(LockFile),
                   "%s" LOCK_PREFIX "%s" LOCK_SUFFIX, tmppath, port);

    /*
     * Create a temporary file containing our PID.  Attempt three times
     * to create the file.
     */
    StillLocking = TRUE;
    i = 0;
    do {
        i++;
        lfd = open(tmp, O_CREAT | O_EXCL | O_WRONLY, 0644);
        if (lfd < 0)
            sleep(2);
        else
            break;
    } while (i < 3);
    if (lfd < 0) {
        unlink(tmp);
        i = 0;
        do {
            i++;
            lfd = open(tmp, O_CREAT | O_EXCL | O_WRONLY, 0644);
            if (lfd < 0)
                sleep(2);
            else
                break;
        } while (i < 3);
    }
    if (lfd < 0)
        FatalError("Could not create lock file in %s\n", tmp);
    snprintf(pid_str, sizeof(pid_str), "%10ld\n", (long) getpid());
    (void) write(lfd, pid_str, 11);
#ifdef __OpenBSD__
    /* if possible give away the lock file to the real uid/gid */
    fchown(lfd, getuid(), getgid());
#endif
    (void) fchmod(lfd, 0444);
    (void) close(lfd);

    /*
     * OK.  Now the tmp file exists.  Try three times to move it in place
     * for the lock.
     */
    i = 0;
    haslock = 0;
    while ((!haslock) && (i++ < 3)) {
        haslock = (link(tmp, LockFile) == 0);
        if (haslock) {
            /*
             * We're done.
             */
            break;
        }
        else {
            /*
             * Read the pid from the existing file
             */
            lfd = open(LockFile, O_RDONLY | O_NOFOLLOW);
            if (lfd < 0) {
                unlink(tmp);
                FatalError("Can't read lock file %s\n", LockFile);
            }
            pid_str[0] = '\0';
            if (read(lfd, pid_str, 11) != 11) {
                /*
                 * Bogus lock file.
                 */
                unlink(LockFile);
                close(lfd);
                continue;
            }
            pid_str[11] = '\0';
            sscanf(pid_str, "%d", &l_pid);
            close(lfd);

            /*
             * Now try to kill the PID to see if it exists.
             */
            errno = 0;
            t = kill(l_pid, 0);
            if ((t < 0) && (errno == ESRCH)) {
                /*
                 * Stale lock file.
                 */
                unlink(LockFile);
                continue;
            }
            else if (((t < 0) && (errno == EPERM)) || (t == 0)) {
                /*
                 * Process is still active.
                 */
                unlink(tmp);
                FatalError
                    ("Server is already active for display %s\n%s %s\n%s\n",
                     port, "\tIf this server is no longer running, remove",
                     LockFile, "\tand start again.");
            }
        }
    }
    unlink(tmp);
    if (!haslock)
        FatalError("Could not create server lock file: %s\n", LockFile);
    StillLocking = FALSE;
}

/*
 * UnlockServer --
 *      Remove the server lock file.
 */
void
UnlockServer(void)
{
    if (nolock)
        return;

    if (!StillLocking) {

        (void) unlink(LockFile);
    }
}

#ifdef X_PRIVSEP
int
ChownLock(uid_t uid, gid_t gid)
{
    return chown(LockFile, uid, gid);
}
#endif

/* Force connections to close on SIGHUP from init */

void
AutoResetServer(int sig)
{
    int olderrno = errno;

    dispatchException |= DE_RESET;
    isItTimeToYield = TRUE;
    errno = olderrno;
}

/* Force connections to close and then exit on SIGTERM, SIGINT */

void
GiveUp(int sig)
{
    int olderrno = errno;

    dispatchException |= DE_TERMINATE;
    isItTimeToYield = TRUE;
    errno = olderrno;
}

#if (defined WIN32 && defined __MINGW32__) || defined(__CYGWIN__)
CARD32
GetTimeInMillis(void)
{
    return GetTickCount();
}
#else
CARD32
GetTimeInMillis(void)
{
    struct timeval tv;

#ifdef MONOTONIC_CLOCK
    struct timespec tp;
    static clockid_t clockid;

    if (!clockid) {
#ifdef CLOCK_MONOTONIC_COARSE
        if (clock_getres(CLOCK_MONOTONIC_COARSE, &tp) == 0 &&
            (tp.tv_nsec / 1000) <= 1000 &&
            clock_gettime(CLOCK_MONOTONIC_COARSE, &tp) == 0)
            clockid = CLOCK_MONOTONIC_COARSE;
        else
#endif
        if (clock_gettime(CLOCK_MONOTONIC, &tp) == 0)
            clockid = CLOCK_MONOTONIC;
        else
            clockid = ~0L;
    }
    if (clockid != ~0L && clock_gettime(clockid, &tp) == 0)
        return (tp.tv_sec * 1000) + (tp.tv_nsec / 1000000L);
#endif

    X_GETTIMEOFDAY(&tv);
    return (tv.tv_sec * 1000) + (tv.tv_usec / 1000);
}
#endif

void
AdjustWaitForDelay(pointer waitTime, unsigned long newdelay)
{
    static struct timeval delay_val;
    struct timeval **wt = (struct timeval **) waitTime;
    unsigned long olddelay;

    if (*wt == NULL) {
        delay_val.tv_sec = newdelay / 1000;
        delay_val.tv_usec = 1000 * (newdelay % 1000);
        *wt = &delay_val;
    }
    else {
        olddelay = (*wt)->tv_sec * 1000 + (*wt)->tv_usec / 1000;
        if (newdelay < olddelay) {
            (*wt)->tv_sec = newdelay / 1000;
            (*wt)->tv_usec = 1000 * (newdelay % 1000);
        }
    }
}

void
UseMsg(void)
{
    ErrorF("use: X [:<display>] [option]\n");
    ErrorF("-a #                   default pointer acceleration (factor)\n");
    ErrorF("-ac                    disable access control restrictions\n");
    ErrorF("-audit int             set audit trail level\n");
    ErrorF("-auth file             select authorization file\n");
    ErrorF("-br                    create root window with black background\n");
    ErrorF("+bs                    enable any backing store support\n");
    ErrorF("-bs                    disable any backing store support\n");
    ErrorF("-c                     turns off key-click\n");
    ErrorF("c #                    key-click volume (0-100)\n");
    ErrorF("-cc int                default color visual class\n");
    ErrorF("-nocursor              disable the cursor\n");
    ErrorF("-core                  generate core dump on fatal error\n");
    ErrorF("-dpi int               screen resolution in dots per inch\n");
#ifdef DPMSExtension
    ErrorF("-dpms                  disables VESA DPMS monitor control\n");
#endif
    ErrorF
        ("-deferglyphs [none|all|16] defer loading of [no|all|16-bit] glyphs\n");
    ErrorF("-f #                   bell base (0-100)\n");
    ErrorF("-fc string             cursor font\n");
    ErrorF("-fn string             default font name\n");
    ErrorF("-fp string             default font path\n");
    ErrorF("-help                  prints message with these options\n");
    ErrorF("-I                     ignore all remaining arguments\n");
#ifdef RLIMIT_DATA
    ErrorF("-ld int                limit data space to N Kb\n");
#endif
#ifdef RLIMIT_NOFILE
    ErrorF("-lf int                limit number of open files to N\n");
#endif
#ifdef RLIMIT_STACK
    ErrorF("-ls int                limit stack space to N Kb\n");
#endif
    ErrorF("-nolock                disable the locking mechanism\n");
    ErrorF("-nolisten string       don't listen on protocol\n");
    ErrorF("-noreset               don't reset after last client exists\n");
    ErrorF("-background [none]     create root window with no background\n");
    ErrorF("-reset                 reset after last client exists\n");
    ErrorF("-p #                   screen-saver pattern duration (minutes)\n");
    ErrorF("-pn                    accept failure to listen on all ports\n");
    ErrorF("-nopn                  reject failure to listen on all ports\n");
    ErrorF("-r                     turns off auto-repeat\n");
    ErrorF("r                      turns on auto-repeat \n");
    ErrorF("-render [default|mono|gray|color] set render color alloc policy\n");
#ifndef __OpenBSD__
    ErrorF("-retro                 start with classic stipple and cursor\n");
#else
    ErrorF("-retard                start with black background "
           "and no cursor\n");
#endif
    ErrorF("-s #                   screen-saver timeout (minutes)\n");
    ErrorF("-seat string           seat to run on\n");
    ErrorF("-t #                   default pointer threshold (pixels/t)\n");
    ErrorF("-terminate             terminate at server reset\n");
    ErrorF("-to #                  connection time out\n");
    ErrorF("-tst                   disable testing extensions\n");
    ErrorF("ttyxx                  server started from init on /dev/ttyxx\n");
    ErrorF("v                      video blanking for screen-saver\n");
    ErrorF("-v                     screen-saver without video blanking\n");
    ErrorF("-wm                    WhenMapped default backing-store\n");
    ErrorF("-wr                    create root window with white background\n");
    ErrorF("-maxbigreqsize         set maximal bigrequest size \n");
#ifdef PANORAMIX
    ErrorF("+xinerama              Enable XINERAMA extension\n");
    ErrorF("-xinerama              Disable XINERAMA extension\n");
#endif
    ErrorF
        ("-dumbSched             Disable smart scheduling, enable old behavior\n");
    ErrorF("-schedInterval int     Set scheduler interval in msec\n");
    ErrorF("-sigstop               Enable SIGSTOP based startup\n");
    ErrorF("+extension name        Enable extension\n");
    ErrorF("-extension name        Disable extension\n");
#ifdef XDMCP
    XdmcpUseMsg();
#endif
    XkbUseMsg();
    ddxUseMsg();
}

/*  This function performs a rudimentary sanity check
 *  on the display name passed in on the command-line,
 *  since this string is used to generate filenames.
 *  It is especially important that the display name
 *  not contain a "/" and not start with a "-".
 *                                            --kvajk
 */
static int
VerifyDisplayName(const char *d)
{
    if (d == (char *) 0)
        return 0;               /*  null  */
    if (*d == '\0')
        return 0;               /*  empty  */
    if (*d == '-')
        return 0;               /*  could be confused for an option  */
    if (*d == '.')
        return 0;               /*  must not equal "." or ".."  */
    if (strchr(d, '/') != (char *) 0)
        return 0;               /*  very important!!!  */
    return 1;
}

/*
 * This function parses the command line. Handles device-independent fields
 * and allows ddx to handle additional fields.  It is not allowed to modify
 * argc or any of the strings pointed to by argv.
 */
void
ProcessCommandLine(int argc, char *argv[])
{
    int i, skip;

    defaultKeyboardControl.autoRepeat = TRUE;

#ifdef NO_PART_NET
    PartialNetwork = FALSE;
#else
    PartialNetwork = TRUE;
#endif

    for (i = 1; i < argc; i++) {
        /* call ddx first, so it can peek/override if it wants */
        if ((skip = ddxProcessArgument(argc, argv, i))) {
            i += (skip - 1);
        }
        else if (argv[i][0] == ':') {
            /* initialize display */
            display = argv[i];
            display++;
            if (!VerifyDisplayName(display)) {
                ErrorF("Bad display name: %s\n", display);
                UseMsg();
                FatalError("Bad display name, exiting: %s\n", display);
            }
        }
        else if (strcmp(argv[i], "-a") == 0) {
            if (++i < argc)
                defaultPointerControl.num = atoi(argv[i]);
            else
                UseMsg();
        }
        else if (strcmp(argv[i], "-ac") == 0) {
            defeatAccessControl = TRUE;
        }
        else if (strcmp(argv[i], "-audit") == 0) {
            if (++i < argc)
                auditTrailLevel = atoi(argv[i]);
            else
                UseMsg();
        }
        else if (strcmp(argv[i], "-auth") == 0) {
            if (++i < argc)
                InitAuthorization(argv[i]);
            else
                UseMsg();
        }
        else if (strcmp(argv[i], "-br") == 0);  /* default */
        else if (strcmp(argv[i], "+bs") == 0)
            enableBackingStore = TRUE;
        else if (strcmp(argv[i], "-bs") == 0)
            disableBackingStore = TRUE;
        else if (strcmp(argv[i], "c") == 0) {
            if (++i < argc)
                defaultKeyboardControl.click = atoi(argv[i]);
            else
                UseMsg();
        }
        else if (strcmp(argv[i], "-c") == 0) {
            defaultKeyboardControl.click = 0;
        }
        else if (strcmp(argv[i], "-cc") == 0) {
            if (++i < argc)
                defaultColorVisualClass = atoi(argv[i]);
            else
                UseMsg();
        }
        else if (strcmp(argv[i], "-core") == 0) {
#if !defined(WIN32) || !defined(__MINGW32__)
            struct rlimit core_limit;

            getrlimit(RLIMIT_CORE, &core_limit);
            core_limit.rlim_cur = core_limit.rlim_max;
            setrlimit(RLIMIT_CORE, &core_limit);
#endif
            CoreDump = TRUE;
        }
        else if (strcmp(argv[i], "-nocursor") == 0) {
            EnableCursor = FALSE;
        }
        else if (strcmp(argv[i], "-dpi") == 0) {
            if (++i < argc)
                monitorResolution = atoi(argv[i]);
            else
                UseMsg();
        }
#ifdef DPMSExtension
        else if (strcmp(argv[i], "dpms") == 0)
            /* ignored for compatibility */ ;
        else if (strcmp(argv[i], "-dpms") == 0)
            DPMSDisabledSwitch = TRUE;
#endif
        else if (strcmp(argv[i], "-deferglyphs") == 0) {
            if (++i >= argc || !ParseGlyphCachingMode(argv[i]))
                UseMsg();
        }
        else if (strcmp(argv[i], "-f") == 0) {
            if (++i < argc)
                defaultKeyboardControl.bell = atoi(argv[i]);
            else
                UseMsg();
        }
        else if (strcmp(argv[i], "-fc") == 0) {
            if (++i < argc)
                defaultCursorFont = argv[i];
            else
                UseMsg();
        }
        else if (strcmp(argv[i], "-fn") == 0) {
            if (++i < argc)
                defaultTextFont = argv[i];
            else
                UseMsg();
        }
        else if (strcmp(argv[i], "-fp") == 0) {
            if (++i < argc) {
                defaultFontPath = argv[i];
            }
            else
                UseMsg();
        }
        else if (strcmp(argv[i], "-help") == 0) {
            UseMsg();
            exit(0);
        }
        else if ((skip = XkbProcessArguments(argc, argv, i)) != 0) {
            if (skip > 0)
                i += skip - 1;
            else
                UseMsg();
        }
#ifdef RLIMIT_DATA
        else if (strcmp(argv[i], "-ld") == 0) {
            if (++i < argc) {
                limitDataSpace = atoi(argv[i]);
                if (limitDataSpace > 0)
                    limitDataSpace *= 1024;
            }
            else
                UseMsg();
        }
#endif
#ifdef RLIMIT_NOFILE
        else if (strcmp(argv[i], "-lf") == 0) {
            if (++i < argc)
                limitNoFile = atoi(argv[i]);
            else
                UseMsg();
        }
#endif
#ifdef RLIMIT_STACK
        else if (strcmp(argv[i], "-ls") == 0) {
            if (++i < argc) {
                limitStackSpace = atoi(argv[i]);
                if (limitStackSpace > 0)
                    limitStackSpace *= 1024;
            }
            else
                UseMsg();
        }
#endif
        else if (strcmp(argv[i], "-nolock") == 0) {
#if !defined(WIN32) && !defined(__CYGWIN__)
            if (getuid() != 0)
                ErrorF
                    ("Warning: the -nolock option can only be used by root\n");
            else
#endif
                nolock = TRUE;
        }
        else if (strcmp(argv[i], "-nolisten") == 0) {
            if (++i < argc) {
                if (_XSERVTransNoListen(argv[i]))
                    FatalError("Failed to disable listen for %s transport",
                               argv[i]);
            }
            else
                UseMsg();
        }
        else if (strcmp(argv[i], "-noreset") == 0) {
            dispatchExceptionAtReset = 0;
        }
        else if (strcmp(argv[i], "-reset") == 0) {
            dispatchExceptionAtReset = DE_RESET;
        }
        else if (strcmp(argv[i], "-p") == 0) {
            if (++i < argc)
                defaultScreenSaverInterval = ((CARD32) atoi(argv[i])) *
                    MILLI_PER_MIN;
            else
                UseMsg();
        }
        else if (strcmp(argv[i], "-pogo") == 0) {
            dispatchException = DE_TERMINATE;
        }
        else if (strcmp(argv[i], "-pn") == 0)
            PartialNetwork = TRUE;
        else if (strcmp(argv[i], "-nopn") == 0)
            PartialNetwork = FALSE;
        else if (strcmp(argv[i], "r") == 0)
            defaultKeyboardControl.autoRepeat = TRUE;
        else if (strcmp(argv[i], "-r") == 0)
            defaultKeyboardControl.autoRepeat = FALSE;
#ifndef __OpenBSD__
        else if (strcmp(argv[i], "-retro") == 0)
            party_like_its_1989 = TRUE;
#else
        else if ( strcmp( argv[i], "-retard") == 0)
            party_like_its_1989 = FALSE;
#endif
        else if (strcmp(argv[i], "-s") == 0) {
            if (++i < argc)
                defaultScreenSaverTime = ((CARD32) atoi(argv[i])) *
                    MILLI_PER_MIN;
            else
                UseMsg();
        }
        else if (strcmp(argv[i], "-seat") == 0) {
            if (++i < argc)
                SeatId = argv[i];
            else
                UseMsg();
        }
        else if (strcmp(argv[i], "-t") == 0) {
            if (++i < argc)
                defaultPointerControl.threshold = atoi(argv[i]);
            else
                UseMsg();
        }
        else if (strcmp(argv[i], "-terminate") == 0) {
            dispatchExceptionAtReset = DE_TERMINATE;
        }
        else if (strcmp(argv[i], "-to") == 0) {
            if (++i < argc)
                TimeOutValue = ((CARD32) atoi(argv[i])) * MILLI_PER_SECOND;
            else
                UseMsg();
        }
        else if (strcmp(argv[i], "-tst") == 0) {
            noTestExtensions = TRUE;
        }
        else if (strcmp(argv[i], "v") == 0)
            defaultScreenSaverBlanking = PreferBlanking;
        else if (strcmp(argv[i], "-v") == 0)
            defaultScreenSaverBlanking = DontPreferBlanking;
        else if (strcmp(argv[i], "-wm") == 0)
            defaultBackingStore = WhenMapped;
        else if (strcmp(argv[i], "-wr") == 0)
            whiteRoot = TRUE;
        else if (strcmp(argv[i], "-background") == 0) {
            if (++i < argc) {
                if (!strcmp(argv[i], "none"))
                    bgNoneRoot = TRUE;
                else
                    UseMsg();
            }
        }
        else if (strcmp(argv[i], "-maxbigreqsize") == 0) {
            if (++i < argc) {
                long reqSizeArg = atol(argv[i]);

                /* Request size > 128MB does not make much sense... */
                if (reqSizeArg > 0L && reqSizeArg < 128L) {
                    maxBigRequestSize = (reqSizeArg * 1048576L) - 1L;
                }
                else {
                    UseMsg();
                }
            }
            else {
                UseMsg();
            }
        }
#ifdef PANORAMIX
        else if (strcmp(argv[i], "+xinerama") == 0) {
            noPanoramiXExtension = FALSE;
        }
        else if (strcmp(argv[i], "-xinerama") == 0) {
            noPanoramiXExtension = TRUE;
        }
        else if (strcmp(argv[i], "-disablexineramaextension") == 0) {
            PanoramiXExtensionDisabledHack = TRUE;
        }
#endif
        else if (strcmp(argv[i], "-I") == 0) {
            /* ignore all remaining arguments */
            break;
        }
        else if (strncmp(argv[i], "tty", 3) == 0) {
            /* init supplies us with this useless information */
        }
#ifdef XDMCP
        else if ((skip = XdmcpOptions(argc, argv, i)) != i) {
            i = skip - 1;
        }
#endif
        else if (strcmp(argv[i], "-dumbSched") == 0) {
            SmartScheduleDisable = TRUE;
        }
        else if (strcmp(argv[i], "-schedInterval") == 0) {
            if (++i < argc) {
                SmartScheduleInterval = atoi(argv[i]);
                SmartScheduleSlice = SmartScheduleInterval;
            }
            else
                UseMsg();
        }
        else if (strcmp(argv[i], "-schedMax") == 0) {
            if (++i < argc) {
                SmartScheduleMaxSlice = atoi(argv[i]);
            }
            else
                UseMsg();
        }
        else if (strcmp(argv[i], "-render") == 0) {
            if (++i < argc) {
                int policy = PictureParseCmapPolicy(argv[i]);

                if (policy != PictureCmapPolicyInvalid)
                    PictureCmapPolicy = policy;
                else
                    UseMsg();
            }
            else
                UseMsg();
        }
        else if (strcmp(argv[i], "-sigstop") == 0) {
            RunFromSigStopParent = TRUE;
        }
        else if (strcmp(argv[i], "+extension") == 0) {
            if (++i < argc) {
                if (!EnableDisableExtension(argv[i], TRUE))
                    EnableDisableExtensionError(argv[i], TRUE);
            }
            else
                UseMsg();
        }
        else if (strcmp(argv[i], "-extension") == 0) {
            if (++i < argc) {
                if (!EnableDisableExtension(argv[i], FALSE))
                    EnableDisableExtensionError(argv[i], FALSE);
            }
            else
                UseMsg();
        }
        else {
            ErrorF("Unrecognized option: %s\n", argv[i]);
            UseMsg();
            FatalError("Unrecognized option: %s\n", argv[i]);
        }
    }
}

/* Implement a simple-minded font authorization scheme.  The authorization
   name is "hp-hostname-1", the contents are simply the host name. */
int
set_font_authorizations(char **authorizations, int *authlen, pointer client)
{
#define AUTHORIZATION_NAME "hp-hostname-1"
#if defined(TCPCONN) || defined(STREAMSCONN)
    static char *result = NULL;
    static char *p = NULL;

    if (p == NULL) {
        char hname[1024], *hnameptr;
        unsigned int len;

#if defined(IPv6) && defined(AF_INET6)
        struct addrinfo hints, *ai = NULL;
#else
        struct hostent *host;

#ifdef XTHREADS_NEEDS_BYNAMEPARAMS
        _Xgethostbynameparams hparams;
#endif
#endif

        gethostname(hname, 1024);
#if defined(IPv6) && defined(AF_INET6)
        memset(&hints, 0, sizeof(hints));
        hints.ai_flags = AI_CANONNAME;
        if (getaddrinfo(hname, NULL, &hints, &ai) == 0) {
            hnameptr = ai->ai_canonname;
        }
        else {
            hnameptr = hname;
        }
#else
        host = _XGethostbyname(hname, hparams);
        if (host == NULL)
            hnameptr = hname;
        else
            hnameptr = host->h_name;
#endif

        len = strlen(hnameptr) + 1;
        result = malloc(len + sizeof(AUTHORIZATION_NAME) + 4);

        p = result;
        *p++ = sizeof(AUTHORIZATION_NAME) >> 8;
        *p++ = sizeof(AUTHORIZATION_NAME) & 0xff;
        *p++ = (len) >> 8;
        *p++ = (len & 0xff);

        memmove(p, AUTHORIZATION_NAME, sizeof(AUTHORIZATION_NAME));
        p += sizeof(AUTHORIZATION_NAME);
        memmove(p, hnameptr, len);
        p += len;
#if defined(IPv6) && defined(AF_INET6)
        if (ai) {
            freeaddrinfo(ai);
        }
#endif
    }
    *authlen = p - result;
    *authorizations = result;
    return 1;
#else                           /* TCPCONN */
    return 0;
#endif                          /* TCPCONN */
}

void *
Xalloc(unsigned long amount)
{
    /*
     * Xalloc used to return NULL when large amount of memory is requested. In
     * order to catch the buggy callers this warning has been added, slated to
     * removal by anyone who touches this code (or just looks at it) in 2011.
     *
     * -- Mikhail Gusarov
     */
    if ((long) amount <= 0)
        ErrorF("Warning: Xalloc: "
               "requesting unpleasantly large amount of memory: %lu bytes.\n",
               amount);

    return malloc(amount);
}

void *
XNFalloc(unsigned long amount)
{
    void *ptr = malloc(amount);

    if (!ptr)
        FatalError("Out of memory");
    return ptr;
}

void *
Xcalloc(unsigned long amount)
{
    return calloc(1, amount);
}

void *
XNFcalloc(unsigned long amount)
{
    void *ret = calloc(1, amount);

    if (!ret)
        FatalError("XNFcalloc: Out of memory");
    return ret;
}

void *
Xrealloc(void *ptr, unsigned long amount)
{
    /*
     * Xrealloc used to return NULL when large amount of memory is requested. In
     * order to catch the buggy callers this warning has been added, slated to
     * removal by anyone who touches this code (or just looks at it) in 2011.
     *
     * -- Mikhail Gusarov
     */
    if ((long) amount <= 0)
        ErrorF("Warning: Xrealloc: "
               "requesting unpleasantly large amount of memory: %lu bytes.\n",
               amount);

    return realloc(ptr, amount);
}

void *
XNFrealloc(void *ptr, unsigned long amount)
{
    void *ret = realloc(ptr, amount);

    if (!ret)
        FatalError("XNFrealloc: Out of memory");
    return ret;
}

void
Xfree(void *ptr)
{
    free(ptr);
}

char *
Xstrdup(const char *s)
{
    if (s == NULL)
        return NULL;
    return strdup(s);
}

char *
XNFstrdup(const char *s)
{
    char *ret;

    if (s == NULL)
        return NULL;

    ret = strdup(s);
    if (!ret)
        FatalError("XNFstrdup: Out of memory");
    return ret;
}

void
SmartScheduleStopTimer(void)
{
    struct itimerval timer;

    if (SmartScheduleDisable)
        return;
    timer.it_interval.tv_sec = 0;
    timer.it_interval.tv_usec = 0;
    timer.it_value.tv_sec = 0;
    timer.it_value.tv_usec = 0;
    (void) setitimer(ITIMER_REAL, &timer, 0);
}

void
SmartScheduleStartTimer(void)
{
    struct itimerval timer;

    if (SmartScheduleDisable)
        return;
    timer.it_interval.tv_sec = 0;
    timer.it_interval.tv_usec = SmartScheduleInterval * 1000;
    timer.it_value.tv_sec = 0;
    timer.it_value.tv_usec = SmartScheduleInterval * 1000;
    setitimer(ITIMER_REAL, &timer, 0);
}

static void
SmartScheduleTimer(int sig)
{
    SmartScheduleTime += SmartScheduleInterval;
}

void
SmartScheduleInit(void)
{
    struct sigaction act;

    if (SmartScheduleDisable)
        return;

    memset((char *) &act, 0, sizeof(struct sigaction));

    /* Set up the timer signal function */
    act.sa_handler = SmartScheduleTimer;
    sigemptyset(&act.sa_mask);
    sigaddset(&act.sa_mask, SIGALRM);
    if (sigaction(SIGALRM, &act, 0) < 0) {
        perror("sigaction for smart scheduler");
        SmartScheduleDisable = TRUE;
    }
}

#ifdef SIG_BLOCK
static sigset_t PreviousSignalMask;
static int BlockedSignalCount;
#endif

void
OsBlockSignals(void)
{
#ifdef SIG_BLOCK
    if (BlockedSignalCount++ == 0) {
        sigset_t set;

        sigemptyset(&set);
        sigaddset(&set, SIGALRM);
        sigaddset(&set, SIGVTALRM);
#ifdef SIGWINCH
        sigaddset(&set, SIGWINCH);
#endif
#ifdef SIGIO
        sigaddset(&set, SIGIO);
#endif
        sigaddset(&set, SIGTSTP);
        sigaddset(&set, SIGTTIN);
        sigaddset(&set, SIGTTOU);
        sigaddset(&set, SIGCHLD);
        sigprocmask(SIG_BLOCK, &set, &PreviousSignalMask);
    }
#endif
}

void
OsReleaseSignals(void)
{
#ifdef SIG_BLOCK
    if (--BlockedSignalCount == 0) {
        sigprocmask(SIG_SETMASK, &PreviousSignalMask, 0);
    }
#endif
}

/*
 * Pending signals may interfere with core dumping. Provide a
 * mechanism to block signals when aborting.
 */

void
OsAbort(void)
{
#ifndef __APPLE__
    OsBlockSignals();
#endif
    abort();
}

#if !defined(WIN32)
/*
 * "safer" versions of system(3), popen(3) and pclose(3) which give up
 * all privs before running a command.
 *
 * This is based on the code in FreeBSD 2.2 libc.
 *
 * XXX It'd be good to redirect stderr so that it ends up in the log file
 * as well.  As it is now, xkbcomp messages don't end up in the log file.
 */

int
System(const char *command)
{
    int pid, p;
    void (*csig) (int);
    int status;

    if (!command)
        return 1;

    csig = signal(SIGCHLD, SIG_DFL);
    if (csig == SIG_ERR) {
        perror("signal");
        return -1;
    }
    DebugF("System: `%s'\n", command);

    switch (pid = fork()) {
    case -1:                   /* error */
        p = -1;
    case 0:                    /* child */
        if (setgid(getgid()) == -1)
            _exit(127);
        if (setuid(getuid()) == -1)
            _exit(127);
        execl("/bin/sh", "sh", "-c", command, (char *) NULL);
        _exit(127);
    default:                   /* parent */
        do {
            p = waitpid(pid, &status, 0);
        } while (p == -1 && errno == EINTR);

    }

    if (signal(SIGCHLD, csig) == SIG_ERR) {
        perror("signal");
        return -1;
    }

    return p == -1 ? -1 : status;
}

static struct pid {
    struct pid *next;
    FILE *fp;
    int pid;
} *pidlist;

OsSigHandlerPtr old_alarm = NULL;       /* XXX horrible awful hack */

pointer
Popen(const char *command, const char *type)
{
    struct pid *cur;
    FILE *iop;
    int pdes[2], pid;

    if (command == NULL || type == NULL)
        return NULL;

    if ((*type != 'r' && *type != 'w') || type[1])
        return NULL;

    if ((cur = malloc(sizeof(struct pid))) == NULL)
        return NULL;

    if (pipe(pdes) < 0) {
        free(cur);
        return NULL;
    }

    /* Ignore the smart scheduler while this is going on */
    old_alarm = OsSignal(SIGALRM, SIG_IGN);
    if (old_alarm == SIG_ERR) {
        close(pdes[0]);
        close(pdes[1]);
        free(cur);
        perror("signal");
        return NULL;
    }

    switch (pid = fork()) {
    case -1:                   /* error */
        close(pdes[0]);
        close(pdes[1]);
        free(cur);
        if (OsSignal(SIGALRM, old_alarm) == SIG_ERR)
            perror("signal");
        return NULL;
    case 0:                    /* child */
        if (setgid(getgid()) == -1)
            _exit(127);
        if (setuid(getuid()) == -1)
            _exit(127);
        if (*type == 'r') {
            if (pdes[1] != 1) {
                /* stdout */
                dup2(pdes[1], 1);
                close(pdes[1]);
            }
            close(pdes[0]);
        }
        else {
            if (pdes[0] != 0) {
                /* stdin */
                dup2(pdes[0], 0);
                close(pdes[0]);
            }
            close(pdes[1]);
        }
        execl("/bin/sh", "sh", "-c", command, (char *) NULL);
        _exit(127);
    }

    /* Avoid EINTR during stdio calls */
    OsBlockSignals();

    /* parent */
    if (*type == 'r') {
        iop = fdopen(pdes[0], type);
        close(pdes[1]);
    }
    else {
        iop = fdopen(pdes[1], type);
        close(pdes[0]);
    }

    cur->fp = iop;
    cur->pid = pid;
    cur->next = pidlist;
    pidlist = cur;

    DebugF("Popen: `%s', fp = %p\n", command, iop);

    return iop;
}

/* fopen that drops privileges */
pointer
Fopen(const char *file, const char *type)
{
    FILE *iop;

#ifndef HAS_SAVED_IDS_AND_SETEUID
    struct pid *cur;
    int pdes[2], pid;

    if (file == NULL || type == NULL)
        return NULL;

    if ((*type != 'r' && *type != 'w') || type[1])
        return NULL;

    if ((cur = malloc(sizeof(struct pid))) == NULL)
        return NULL;

    if (pipe(pdes) < 0) {
        free(cur);
        return NULL;
    }

    switch (pid = fork()) {
    case -1:                   /* error */
        close(pdes[0]);
        close(pdes[1]);
        free(cur);
        return NULL;
    case 0:                    /* child */
        if (setgid(getgid()) == -1)
            _exit(127);
        if (setuid(getuid()) == -1)
            _exit(127);
        if (*type == 'r') {
            if (pdes[1] != 1) {
                /* stdout */
                dup2(pdes[1], 1);
                close(pdes[1]);
            }
            close(pdes[0]);
        }
        else {
            if (pdes[0] != 0) {
                /* stdin */
                dup2(pdes[0], 0);
                close(pdes[0]);
            }
            close(pdes[1]);
        }
        execl("/bin/cat", "cat", file, (char *) NULL);
        _exit(127);
    }

    /* Avoid EINTR during stdio calls */
    OsBlockSignals();

    /* parent */
    if (*type == 'r') {
        iop = fdopen(pdes[0], type);
        close(pdes[1]);
    }
    else {
        iop = fdopen(pdes[1], type);
        close(pdes[0]);
    }

    cur->fp = iop;
    cur->pid = pid;
    cur->next = pidlist;
    pidlist = cur;

    DebugF("Fopen(%s), fp = %p\n", file, iop);

    return iop;
#else
    int ruid, euid;

    ruid = getuid();
    euid = geteuid();

    if (seteuid(ruid) == -1) {
        return NULL;
    }
    iop = fopen(file, type);

    if (seteuid(euid) == -1) {
        fclose(iop);
        return NULL;
    }
    return iop;
#endif                          /* HAS_SAVED_IDS_AND_SETEUID */
}

int
Pclose(pointer iop)
{
    struct pid *cur, *last;
    int pstat;
    int pid;

    DebugF("Pclose: fp = %p\n", iop);
    fclose(iop);

    for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next)
        if (cur->fp == iop)
            break;
    if (cur == NULL)
        return -1;

    do {
        pid = waitpid(cur->pid, &pstat, 0);
    } while (pid == -1 && errno == EINTR);

    if (last == NULL)
        pidlist = cur->next;
    else
        last->next = cur->next;
    free(cur);

    /* allow EINTR again */
    OsReleaseSignals();

    if (old_alarm && OsSignal(SIGALRM, old_alarm) == SIG_ERR) {
        perror("signal");
        return -1;
    }

    return pid == -1 ? -1 : pstat;
}

int
Fclose(pointer iop)
{
#ifdef HAS_SAVED_IDS_AND_SETEUID
    return fclose(iop);
#else
    return Pclose(iop);
#endif
}

#endif                          /* !WIN32 */

/*
 * CheckUserParameters: check for long command line arguments and long
 * environment variables.  By default, these checks are only done when
 * the server's euid != ruid.  In 3.3.x, these checks were done in an
 * external wrapper utility.
 */

/* Consider LD* variables insecure? */
#ifndef REMOVE_ENV_LD
#define REMOVE_ENV_LD 1
#endif

/* Remove long environment variables? */
#ifndef REMOVE_LONG_ENV
#define REMOVE_LONG_ENV 1
#endif

/*
 * Disallow stdout or stderr as pipes?  It's possible to block the X server
 * when piping stdout+stderr to a pipe.
 *
 * Don't enable this because it looks like it's going to cause problems.
 */
#ifndef NO_OUTPUT_PIPES
#define NO_OUTPUT_PIPES 0
#endif

/* Check args and env only if running setuid (euid == 0 && euid != uid) ? */
#ifndef CHECK_EUID
#ifndef WIN32
#define CHECK_EUID 1
#else
#define CHECK_EUID 0
#endif
#endif

/*
 * Maybe the locale can be faked to make isprint(3) report that everything
 * is printable?  Avoid it by default.
 */
#ifndef USE_ISPRINT
#define USE_ISPRINT 0
#endif

#define MAX_ARG_LENGTH          128
#define MAX_ENV_LENGTH          256
#define MAX_ENV_PATH_LENGTH     2048    /* Limit for *PATH and TERMCAP */

#if USE_ISPRINT
#include <ctype.h>
#define checkPrintable(c) isprint(c)
#else
#define checkPrintable(c) (((c) & 0x7f) >= 0x20 && ((c) & 0x7f) != 0x7f)
#endif

enum BadCode {
    NotBad = 0,
    UnsafeArg,
    ArgTooLong,
    UnprintableArg,
    EnvTooLong,
    OutputIsPipe,
    InternalError
};

#if defined(VENDORSUPPORT)
#define BUGADDRESS VENDORSUPPORT
#elif defined(BUILDERADDR)
#define BUGADDRESS BUILDERADDR
#else
#define BUGADDRESS "xorg@freedesktop.org"
#endif

void
CheckUserParameters(int argc, char **argv, char **envp)
{
    enum BadCode bad = NotBad;
    int i = 0, j;
    char *a, *e = NULL;

#if CHECK_EUID
    if (geteuid() == 0 && getuid() != geteuid())
#endif
    {
        /* Check each argv[] */
        for (i = 1; i < argc; i++) {
            if (strcmp(argv[i], "-fp") == 0) {
                i++;            /* continue with next argument. skip the length check */
                if (i >= argc)
                    break;
            }
            else {
                if (strlen(argv[i]) > MAX_ARG_LENGTH) {
                    bad = ArgTooLong;
                    break;
                }
            }
            a = argv[i];
            while (*a) {
                if (checkPrintable(*a) == 0) {
                    bad = UnprintableArg;
                    break;
                }
                a++;
            }
            if (bad)
                break;
        }
        if (!bad) {
            /* Check each envp[] */
            for (i = 0; envp[i]; i++) {

                /* Check for bad environment variables and values */
#if REMOVE_ENV_LD
                while (envp[i] && (strncmp(envp[i], "LD", 2) == 0)) {
                    for (j = i; envp[j]; j++) {
                        envp[j] = envp[j + 1];
                    }
                }
#endif
                if (envp[i] && (strlen(envp[i]) > MAX_ENV_LENGTH)) {
#if REMOVE_LONG_ENV
                    for (j = i; envp[j]; j++) {
                        envp[j] = envp[j + 1];
                    }
                    i--;
#else
                    char *eq;
                    int len;

                    eq = strchr(envp[i], '=');
                    if (!eq)
                        continue;
                    len = eq - envp[i];
                    e = strndup(envp[i], len);
                    if (!e) {
                        bad = InternalError;
                        break;
                    }
                    if (len >= 4 &&
                        (strcmp(e + len - 4, "PATH") == 0 ||
                         strcmp(e, "TERMCAP") == 0)) {
                        if (strlen(envp[i]) > MAX_ENV_PATH_LENGTH) {
                            bad = EnvTooLong;
                            break;
                        }
                        else {
                            free(e);
                        }
                    }
                    else {
                        bad = EnvTooLong;
                        break;
                    }
#endif
                }
            }
        }
#if NO_OUTPUT_PIPES
        if (!bad) {
            struct stat buf;

            if (fstat(fileno(stdout), &buf) == 0 && S_ISFIFO(buf.st_mode))
                bad = OutputIsPipe;
            if (fstat(fileno(stderr), &buf) == 0 && S_ISFIFO(buf.st_mode))
                bad = OutputIsPipe;
        }
#endif
    }
    switch (bad) {
    case NotBad:
        return;
    case UnsafeArg:
        ErrorF("Command line argument number %d is unsafe\n", i);
        break;
    case ArgTooLong:
        ErrorF("Command line argument number %d is too long\n", i);
        break;
    case UnprintableArg:
        ErrorF("Command line argument number %d contains unprintable"
               " characters\n", i);
        break;
    case EnvTooLong:
        ErrorF("Environment variable `%s' is too long\n", e);
        break;
    case OutputIsPipe:
        ErrorF("Stdout and/or stderr is a pipe\n");
        break;
    case InternalError:
        ErrorF("Internal Error\n");
        break;
    default:
        ErrorF("Unknown error\n");
        break;
    }
    FatalError("X server aborted because of unsafe environment\n");
}

/*
 * CheckUserAuthorization: check if the user is allowed to start the
 * X server.  This usually means some sort of PAM checking, and it is
 * usually only done for setuid servers (uid != euid).
 */

#ifdef USE_PAM
#include <security/pam_appl.h>
#include <security/pam_misc.h>
#include <pwd.h>
#endif                          /* USE_PAM */

void
CheckUserAuthorization(void)
{
#ifdef USE_PAM
    static struct pam_conv conv = {
        misc_conv,
        NULL
    };

    pam_handle_t *pamh = NULL;
    struct passwd *pw;
    int retval;

    if (getuid() != geteuid()) {
        pw = getpwuid(getuid());
        if (pw == NULL)
            FatalError("getpwuid() failed for uid %d\n", getuid());

        retval = pam_start("xserver", pw->pw_name, &conv, &pamh);
        if (retval != PAM_SUCCESS)
            FatalError("pam_start() failed.\n"
                       "\tMissing or mangled PAM config file or module?\n");

        retval = pam_authenticate(pamh, 0);
        if (retval != PAM_SUCCESS) {
            pam_end(pamh, retval);
            FatalError("PAM authentication failed, cannot start X server.\n"
                       "\tPerhaps you do not have console ownership?\n");
        }

        retval = pam_acct_mgmt(pamh, 0);
        if (retval != PAM_SUCCESS) {
            pam_end(pamh, retval);
            FatalError("PAM authentication failed, cannot start X server.\n"
                       "\tPerhaps you do not have console ownership?\n");
        }

        /* this is not a session, so do not do session management */
        pam_end(pamh, PAM_SUCCESS);
    }
#endif
}

/*
 * Tokenize a string into a NULL terminated array of strings. Always returns
 * an allocated array unless an error occurs.
 */
char **
xstrtokenize(const char *str, const char *separators)
{
    char **list, **nlist;
    char *tok, *tmp;
    unsigned num = 0, n;

    if (!str)
        return NULL;
    list = calloc(1, sizeof(*list));
    if (!list)
        return NULL;
    tmp = strdup(str);
    if (!tmp)
        goto error;
    for (tok = strtok(tmp, separators); tok; tok = strtok(NULL, separators)) {
        nlist = realloc(list, (num + 2) * sizeof(*list));
        if (!nlist)
            goto error;
        list = nlist;
        list[num] = strdup(tok);
        if (!list[num])
            goto error;
        list[++num] = NULL;
    }
    free(tmp);
    return list;

 error:
    free(tmp);
    for (n = 0; n < num; n++)
        free(list[n]);
    free(list);
    return NULL;
}