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cdesktopenv/cde/programs/dtlogin/server.c

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/*
* CDE - Common Desktop Environment
*
* Copyright (c) 1993-2012, The Open Group. All rights reserved.
*
* These libraries and programs are free software; you can
* redistribute them and/or modify them under the terms of the GNU
* Lesser General Public License as published by the Free Software
* Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* These libraries and programs are distributed in the hope that
* they will be useful, but WITHOUT ANY WARRANTY; without even the
* implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
* PURPOSE. See the GNU Lesser General Public License for more
* details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with these librararies and programs; if not, write
* to the Free Software Foundation, Inc., 51 Franklin Street, Fifth
* Floor, Boston, MA 02110-1301 USA
*/
/* *
* (c) Copyright 1993, 1994 Hewlett-Packard Company *
* (c) Copyright 1993, 1994 International Business Machines Corp. *
* (c) Copyright 1993, 1994 Sun Microsystems, Inc. *
* (c) Copyright 1993, 1994 Novell, Inc. *
*/
/*
* xdm - display manager daemon
*
* $XConsortium: server.c /main/4 1995/10/27 16:14:56 rswiston $
*
* Copyright 1988 Massachusetts Institute of Technology
*
* 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 name of M.I.T. not be used in advertising or
* publicity pertaining to distribution of the software without specific,
* written prior permission. M.I.T. makes no representations about the
* suitability of this software for any purpose. It is provided "as is"
* without express or implied warranty.
*
* Author: Keith Packard, MIT X Consortium
*/
# include <sys/types.h>
# include <sys/signal.h>
# include <setjmp.h>
# include <errno.h>
# include <pwd.h>
# include "dm.h"
# include "vgmsg.h"
static receivedUsr1;
/***************************************************************************
*
* Local procedure declarations
*
***************************************************************************/
static const char * _SysErrorMsg( int n) ;
static SIGVAL CatchUsr1( int arg ) ;
static void GetRemoteAddress( struct display *d, int fd) ;
static SIGVAL PingBlocked( int arg ) ;
static SIGVAL PingLost( int arg ) ;
static SIGVAL abortOpen( int arg ) ;
static int serverPause( unsigned t, int serverPid) ;
static SIGVAL serverPauseAbort( int arg ) ;
static SIGVAL serverPauseUsr1( int arg ) ;
/***************************************************************************
*
* Global variables
*
***************************************************************************/
static Display *dpy;
static SIGVAL
CatchUsr1( int arg )
{
#if defined(SYSV) || defined(SVR4)
(void) signal (SIGUSR1, CatchUsr1);
#endif
Debug ("Display Manager caught SIGUSR1\n");
++receivedUsr1;
}
static const char *
_SysErrorMsg( int n )
{
const char *s = strerror(n);
return (s ? s : "no such error");
}
int
StartServerOnce( struct display *d )
{
char **f;
char **argv;
char arg[1024];
int pid;
char **env;
extern struct passwd puser; /* pseudo_user password entry */
Debug ("Starting server for %s\n", d->name);
receivedUsr1 = 0;
signal (SIGUSR1, CatchUsr1);
argv = d->argv;
switch (pid = fork ()) {
case 0:
CleanUpChild ();
if (d->authFile) {
sprintf (arg, "-auth %s", d->authFile);
argv = parseArgs (argv, arg);
}
if (!argv) {
LogError(ReadCatalog(MC_LOG_SET,MC_LOG_NO_ARGS,MC_DEF_LOG_NO_ARGS));
exit(1);
}
Debug("Server invoked as ");
for (f = argv; *f; f++)
Debug ("'%s' ", *f);
Debug ("\n");
/*
* set the permissions on console devices to pseudo-user.
* run the server as a pseudo-user, not root...
*/
#ifdef sun
if (solaris_setdevperm(d->gettyLine, puser.pw_uid, puser.pw_gid) == 0)
Debug ("Unable to set permissions on console devices ..\n");
else {
#endif
if(-1 == setgid (puser.pw_gid)) {
Debug ("setgid() failed setting %d\n", puser.pw_gid);
}
if(-1 == setuid (puser.pw_uid)) {
Debug ("setuid() failed setting %d\n", puser.pw_uid);
}
#ifdef sun
}
#endif
/*
* build the server environment (if any)...
*/
env = 0;
if (d->environStr && strlen(d->environStr) > 0)
env = parseEnv(env, d->environStr);
#ifdef sun
if (getEnv (env, "OPENWINHOME") == NULL)
env = setEnv(env, "OPENWINHOME", "/usr/openwin");
#endif
#ifdef _AIX
if (getEnv (env, "ODMDIR") == NULL)
env = setEnv(env, "ODMDIR", "/etc/objrepos");
#ifdef _POWER
env = setEnv(env, "XTOEXEC", "true"); /* flag for xserverrc */
#endif
#endif
/*
* give the server SIGUSR1 ignored,
* it will notice that and send SIGUSR1
* when ready
*/
signal (SIGUSR1, SIG_IGN);
(void) execve (argv[0], argv, env);
LogError(ReadCatalog(
MC_LOG_SET,MC_LOG_NO_EXESRV,MC_DEF_LOG_NO_EXESRV),argv[0]);
exit(1);
case -1:
LogError(ReadCatalog(MC_LOG_SET,MC_LOG_FAIL_FORK,MC_DEF_LOG_FAIL_FORK));
return 0;
default:
break;
}
Debug ("Server started. Process ID = %d\n", pid);
d->serverPid = pid;
if (serverPause ((unsigned) d->openDelay, pid))
return FALSE;
return TRUE;
}
int
StartServer( struct display *d )
{
int i;
int ret = FALSE;
i = 0;
while (d->serverAttempts == 0 || i < d->serverAttempts)
{
if ((ret = StartServerOnce (d)) == TRUE)
break;
sleep (d->openDelay);
i++;
}
return ret;
}
/*
* sleep for t seconds, return 1 if the server is dead when
* the sleep finishes, 0 else
*/
static jmp_buf pauseAbort;
static int serverPauseRet;
static SIGVAL
serverPauseAbort( int arg )
{
Debug ("Display Manager pause timed out\n");
longjmp (pauseAbort, 1);
}
static SIGVAL
serverPauseUsr1( int arg )
{
Debug ("Display Manager pause received SIGUSR1\n");
++receivedUsr1;
longjmp (pauseAbort, 1);
}
static int
serverPause( unsigned t, int serverPid )
{
int pid;
serverPauseRet = 0;
Debug ("Display Manager pausing until SIGUSR1 from server or timeout\n");
if (!setjmp (pauseAbort)) {
signal (SIGALRM, serverPauseAbort);
signal (SIGUSR1, serverPauseUsr1);
#ifdef SYSV
if (receivedUsr1)
alarm ((unsigned) 1);
else
alarm (t);
#else
if (!receivedUsr1)
alarm (t);
else
Debug ("ServerPause(): already received USR1\n");
#endif
for (;;) {
#ifdef SYSV
pid = wait ((waitType *) 0);
#else
if (!receivedUsr1)
pid = wait ((waitType *) 0);
else
# ifdef SVR4
{
int dummy;
pid = waitpid ((pid_t) 0,&dummy,WNOHANG);
}
# else
pid = wait3 ((waitType *) 0, WNOHANG,
(struct rusage *) 0);
# endif
#endif
if (pid == serverPid ||
pid == -1 && errno == ECHILD)
{
Debug ("Server dead\n");
serverPauseRet = 1;
break;
}
#ifndef SYSV
if (pid == 0) {
Debug ("Server alive and kicking\n");
break;
}
#endif
}
}
alarm ((unsigned) 0);
signal (SIGALRM, SIG_DFL);
signal (SIGUSR1, CatchUsr1);
if (serverPauseRet) {
Debug ("Server died\n");
LogError(ReadCatalog(MC_LOG_SET,MC_LOG_SRV_DIED,MC_DEF_LOG_SRV_DIED));
}
return serverPauseRet;
}
/*
* this code is complicated by some TCP failings. On
* many systems, the connect will occasionally hang forever,
* this trouble is avoided by setting up a timeout to longjmp
* out of the connect (possibly leaving piles of garbage around
* inside Xlib) and give up, terminating the server.
*/
static jmp_buf openAbort;
static SIGVAL
abortOpen( int arg )
{
longjmp (openAbort, 1);
}
static void
GetRemoteAddress( struct display *d, int fd )
{
char buf[512];
int len = sizeof (buf);
if (d->peer)
free ((char *) d->peer);
getpeername (fd, (struct sockaddr *) buf, &len);
d->peerlen = 0;
if (len)
{
d->peer = (struct sockaddr *) malloc (len);
if (d->peer)
{
bcopy (buf, (char *) d->peer, len);
d->peerlen = len;
}
}
Debug ("Got remote address %s %d\n", d->name, d->peerlen);
}
/****************************************************************************
*
* LogOpenError()
*
* If d->startAttempts is a large number and a connection cannot be made to
* the server, the error log can fill up rapidly with error messages. This
* could be common in X-terminals that do not support XDMCP and are turned
* off over a weekend. This routine attempts to reduce the number of error
* messages logged in this scenario.
*
****************************************************************************/
int
LogOpenError( int count )
{
if ( count <= 10 ) return 1;
if ( count <= 100 && (count % 10 == 0) ) return 1;
if ( count <= 500 && (count % 50 == 0) ) return 1;
if ( (count % 100 == 0) ) return 1;
return 0;
}
int
WaitForServer( struct display *d )
{
int i;
for (i = 0; i < (d->openRepeat > 0 ? d->openRepeat : 1); i++) {
(void) signal (SIGALRM, abortOpen);
(void) alarm ((unsigned) d->openTimeout);
if (!setjmp (openAbort)) {
Debug ("Before XOpenDisplay(%s)\n", d->name);
errno = 0;
dpy = XOpenDisplay (d->name);
(void) alarm ((unsigned) 0);
(void) signal (SIGALRM, SIG_DFL);
Debug ("After XOpenDisplay()\n");
if (dpy) {
if (d->displayType.location == Foreign)
GetRemoteAddress (d, ConnectionNumber (dpy));
RegisterCloseOnFork (ConnectionNumber (dpy));
(void) fcntl (ConnectionNumber (dpy), F_SETFD, 0);
return 1;
} else {
Debug ("OpenDisplay failed %d (%s)\n",
errno, _SysErrorMsg (errno));
}
Debug ("Waiting for server to start %d\n", i);
sleep ((unsigned) d->openDelay);
} else {
Debug ("Hung in open, aborting\n");
if (LogOpenError(d->startTries))
LogError(ReadCatalog(
MC_LOG_SET,MC_LOG_HUNG_DPY,MC_DEF_LOG_HUNG_DPY),
d->name, d->startTries);
(void) signal (SIGALRM, SIG_DFL);
break;
}
}
Debug ("Giving up on server\n");
if (LogOpenError(d->startTries))
LogError(ReadCatalog(
MC_LOG_SET,MC_LOG_FAIL_SRVOPEN,MC_DEF_LOG_FAIL_SRVOPEN),
d->startTries, d->name);
return 0;
}
void
ResetServer( struct display *d )
{
if (dpy && d->displayType.origin != FromXDMCP)
pseudoReset (dpy);
}
/****************************************************************************
*
* Server pinging routines...
*
* These routines attempt to determine if the server is still alive.
* Periodically (d->pingInterval) an XSync is sent to the server. If an I/O
* error occurs, then the connection has been lost and the server needs to
* be reset. If the server is blocked for some reason (i.e. server grab) the
* XSync will block until a local timer expires. In this case, we just note
* the block and continue...
*
* 7/26/90 - prr
* The XSync was replaced by a socket-level ping. For some reason, an XSync
* to a grabbed server causes a subsequent pseudoReset (KillClients) to not
* kill all clients. The socket ping is not affected by a grabbed server,
* but it cannot detect a server shutdown and restart within one ping
* interval.
*
****************************************************************************/
static jmp_buf pingTime;
static int serverDead = FALSE;
static SIGVAL
PingLost( int arg )
{
serverDead = TRUE;
longjmp (pingTime, 1);
}
static SIGVAL
PingBlocked( int arg )
{
serverDead = FALSE;
longjmp (pingTime, 1);
}
int
PingServer( struct display *d, Display *alternateDpy )
{
int (*oldError)();
SIGVAL (*oldSig)();
int oldAlarm;
if (!alternateDpy)
alternateDpy = dpy;
oldError = XSetIOErrorHandler ((XIOErrorHandler)PingLost);
oldAlarm = alarm (0);
oldSig = signal (SIGALRM, PingBlocked);
alarm (d->pingTimeout * 60);
if (!setjmp (pingTime))
{
Debug ("Ping server\n");
XNoOp (alternateDpy);
XSync (alternateDpy, 0);
Debug ("Server alive\n");
while (XPending(alternateDpy)) {
XEvent event;
XNextEvent(alternateDpy, &event);
}
}
else
{
if ( serverDead ) {
Debug ("Server dead\n");
alarm (0);
signal (SIGALRM, SIG_DFL);
XSetIOErrorHandler (oldError);
return 0;
}
else
Debug ("Server blocked, continuing...\n");
}
alarm (0);
signal (SIGALRM, oldSig);
alarm (oldAlarm);
XSetIOErrorHandler (oldError);
return 1;
}
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