xenocara/app/xdm/dm.c
2007-08-05 19:00:25 +00:00

974 lines
21 KiB
C

/* $XdotOrg: $ */
/* $Xorg: dm.c,v 1.5 2001/02/09 02:05:40 xorgcvs Exp $ */
/*
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.
*/
/* $XFree86: xc/programs/xdm/dm.c,v 3.23 2003/09/17 05:48:32 herrb Exp $ */
/*
* xdm - display manager daemon
* Author: Keith Packard, MIT X Consortium
*
* display manager
*/
# include "dm.h"
# include "dm_auth.h"
# include "dm_error.h"
# include <stdio.h>
#ifdef X_POSIX_C_SOURCE
#define _POSIX_C_SOURCE X_POSIX_C_SOURCE
#include <signal.h>
#undef _POSIX_C_SOURCE
#else
#if defined(X_NOT_POSIX) || defined(_POSIX_SOURCE)
#include <signal.h>
#else
#define _POSIX_SOURCE
#include <signal.h>
#undef _POSIX_SOURCE
#endif
#endif
#ifdef __NetBSD__
#include <sys/param.h>
#endif
#ifdef USESECUREWARE
#include <prot.h>
#endif
#ifndef sigmask
#define sigmask(m) (1 << ((m - 1)))
#endif
# include <sys/stat.h>
# include <errno.h>
# include <X11/Xfuncproto.h>
# include <X11/Xatom.h>
# include <stdarg.h>
# include <stdint.h>
#ifndef F_TLOCK
#ifndef X_NOT_POSIX
# include <unistd.h>
#endif
#endif
#if defined(SVR4) && !defined(sun)
extern FILE *fdopen();
#endif
static SIGVAL StopAll (int n), RescanNotify (int n);
static void RescanServers (void);
static void RestartDisplay (struct display *d, int forceReserver);
static void ScanServers (void);
static void SetAccessFileTime (void);
static void SetConfigFileTime (void);
static void StartDisplays (void);
static void TerminateProcess (pid_t pid, int signal);
volatile int Rescan;
static long ServersModTime, ConfigModTime, AccessFileModTime;
int nofork_session = 0;
#ifndef NOXDMTITLE
static char *Title;
static int TitleLen;
#endif
#ifndef UNRELIABLE_SIGNALS
static SIGVAL ChildNotify (int n);
#endif
static int StorePid (void);
static pid_t parent_pid = -1; /* PID of parent xdm process */
int
main (int argc, char **argv)
{
int oldpid;
mode_t oldumask;
char cmdbuf[1024];
/* make sure at least world write access is disabled */
if (((oldumask = umask(022)) & 002) == 002)
(void) umask (oldumask);
#ifndef NOXDMTITLE
Title = argv[0];
TitleLen = (argv[argc - 1] + strlen(argv[argc - 1])) - Title;
#endif
#ifdef USESECUREWARE
set_auth_parameters (argc, argv);
#endif
/*
* Step 1 - load configuration parameters
*/
InitResources (argc, argv);
SetConfigFileTime ();
LoadDMResources ();
/*
* Only allow root to run in non-debug mode to avoid problems
*/
if (debugLevel == 0 && getuid() != 0)
{
fprintf (stderr, "Only root wants to run %s\n", argv[0]);
exit (1);
}
if (debugLevel == 0 && daemonMode)
BecomeDaemon ();
if (debugLevel >= 10)
nofork_session = 1;
/* SUPPRESS 560 */
if ((oldpid = StorePid ()))
{
if (oldpid == -1)
LogError ("Can't create/lock pid file %s\n", pidFile);
else
LogError ("Can't lock pid file %s, another xdm is running (pid %d)\n",
pidFile, oldpid);
exit (1);
}
if (debugLevel == 0)
InitErrorLog ();
if (nofork_session == 0) {
/* Clean up any old Authorization files */
/* AUD: all good? */
snprintf(cmdbuf, sizeof(cmdbuf), "/bin/rm -f %s/authdir/authfiles/A*", authDir);
system(cmdbuf);
}
#if!defined(ARC4_RANDOM) && !defined(DEV_RANDOM)
AddOtherEntropy ();
#endif
#ifdef XDMCP
init_session_id ();
CreateWellKnownSockets ();
#else
Debug ("xdm: not compiled for XDMCP\n");
#endif
parent_pid = getpid ();
(void) Signal (SIGTERM, StopAll);
(void) Signal (SIGINT, StopAll);
/*
* Step 2 - Read /etc/Xservers and set up
* the socket.
*
* Keep a sub-daemon running
* for each entry
*/
SetAccessFileTime ();
#ifdef XDMCP
ScanAccessDatabase ();
UpdateListenSockets ();
#endif
ScanServers ();
StartDisplays ();
#if !defined(ARC4_RANDOM) && !defined(DEV_RANDOM)
AddOtherEntropy();
#endif
(void) Signal (SIGHUP, RescanNotify);
#ifndef UNRELIABLE_SIGNALS
(void) Signal (SIGCHLD, ChildNotify);
#endif
while (
#ifdef XDMCP
AnyWellKnownSockets() ||
#endif
AnyDisplaysLeft ())
{
if (Rescan)
{
RescanServers ();
Rescan = 0;
}
#if defined(UNRELIABLE_SIGNALS) || !defined(XDMCP)
WaitForChild ();
#else
WaitForSomething ();
#endif
}
Debug ("Nothing left to do, exiting\n");
exit(0);
/*NOTREACHED*/
}
/* ARGSUSED */
static SIGVAL
RescanNotify (int n)
{
int olderrno = errno;
Debug ("Caught SIGHUP\n");
Rescan = 1;
#ifdef SIGNALS_RESET_WHEN_CAUGHT
(void) Signal (SIGHUP, RescanNotify);
#endif
errno = olderrno;
}
static void
ScanServers (void)
{
char lineBuf[10240];
int len;
FILE *serversFile;
struct stat statb;
static DisplayType acceptableTypes[] =
{ { Local, Permanent, FromFile },
{ Foreign, Permanent, FromFile },
};
#define NumTypes (sizeof (acceptableTypes) / sizeof (acceptableTypes[0]))
if (servers[0] == '/')
{
serversFile = fopen (servers, "r");
if (serversFile == NULL)
{
LogError ("cannot access servers file %s\n", servers);
return;
}
if (ServersModTime == 0)
{
fstat (fileno (serversFile), &statb);
ServersModTime = statb.st_mtime;
}
while (fgets (lineBuf, sizeof (lineBuf)-1, serversFile))
{
len = strlen (lineBuf);
if (lineBuf[len-1] == '\n')
lineBuf[len-1] = '\0';
ParseDisplay (lineBuf, acceptableTypes, NumTypes);
}
fclose (serversFile);
}
else
{
ParseDisplay (servers, acceptableTypes, NumTypes);
}
}
static void
MarkDisplay (struct display *d)
{
d->state = MissingEntry;
}
static void
RescanServers (void)
{
Debug ("rescanning servers\n");
LogInfo ("Rescanning both config and servers files\n");
ForEachDisplay (MarkDisplay);
SetConfigFileTime ();
ReinitResources ();
LoadDMResources ();
ScanServers ();
SetAccessFileTime ();
#ifdef XDMCP
ScanAccessDatabase ();
UpdateListenSockets ();
#endif
StartDisplays ();
}
static void
SetConfigFileTime (void)
{
struct stat statb;
if (stat (config, &statb) != -1)
ConfigModTime = statb.st_mtime;
}
static void
SetAccessFileTime (void)
{
struct stat statb;
if (stat (accessFile, &statb) != -1)
AccessFileModTime = statb.st_mtime;
}
static void
RescanIfMod (void)
{
struct stat statb;
if (config && stat (config, &statb) != -1)
{
if (statb.st_mtime != ConfigModTime)
{
Debug ("Config file %s has changed, rereading\n", config);
LogInfo ("Rereading configuration file %s\n", config);
ConfigModTime = statb.st_mtime;
ReinitResources ();
LoadDMResources ();
}
}
if (servers[0] == '/' && stat(servers, &statb) != -1)
{
if (statb.st_mtime != ServersModTime)
{
Debug ("Servers file %s has changed, rescanning\n", servers);
LogInfo ("Rereading servers file %s\n", servers);
ServersModTime = statb.st_mtime;
ForEachDisplay (MarkDisplay);
ScanServers ();
}
}
#ifdef XDMCP
if (accessFile && accessFile[0] && stat (accessFile, &statb) != -1)
{
if (statb.st_mtime != AccessFileModTime)
{
Debug ("Access file %s has changed, rereading\n", accessFile);
LogInfo ("Rereading access file %s\n", accessFile);
AccessFileModTime = statb.st_mtime;
ScanAccessDatabase ();
UpdateListenSockets();
}
}
#endif
}
/*
* catch a SIGTERM, kill all displays and exit
*/
/* ARGSUSED */
static SIGVAL
StopAll (int n)
{
int olderrno = errno;
if (parent_pid != getpid())
{
/*
* We are a child xdm process that was killed by the
* master xdm before we were able to return from fork()
* and remove this signal handler.
*
* See defect XWSog08655 for more information.
*/
Debug ("Child xdm caught SIGTERM before it remove that signal.\n");
(void) Signal (n, SIG_DFL);
TerminateProcess (getpid(), SIGTERM);
errno = olderrno;
return;
}
Debug ("Shutting down entire manager\n");
#ifdef XDMCP
DestroyWellKnownSockets ();
#endif
ForEachDisplay (StopDisplay);
#ifdef SIGNALS_RESET_WHEN_CAUGHT
/* to avoid another one from killing us unceremoniously */
(void) Signal (SIGTERM, StopAll);
(void) Signal (SIGINT, StopAll);
#endif
errno = olderrno;
}
/*
* notice that a child has died and may need another
* sub-daemon started
*/
int ChildReady;
#ifndef UNRELIABLE_SIGNALS
/* ARGSUSED */
static SIGVAL
ChildNotify (int n)
{
int olderrno = errno;
ChildReady = 1;
#ifdef ISC
(void) Signal (SIGCHLD, ChildNotify);
#endif
errno = olderrno;
}
#endif
void
WaitForChild (void)
{
pid_t pid;
struct display *d;
waitType status;
#if !defined(X_NOT_POSIX) && !defined(__UNIXOS2__)
sigset_t mask, omask;
#else
int omask;
#endif
#ifdef UNRELIABLE_SIGNALS
/* XXX classic System V signal race condition here with RescanNotify */
if ((pid = wait (&status)) != -1)
#else
#ifndef X_NOT_POSIX
sigemptyset(&mask);
sigaddset(&mask, SIGCHLD);
sigaddset(&mask, SIGHUP);
sigprocmask(SIG_BLOCK, &mask, &omask);
Debug ("signals blocked\n");
#else
omask = sigblock (sigmask (SIGCHLD) | sigmask (SIGHUP));
Debug ("signals blocked, mask was 0x%x\n", omask);
#endif
if (!ChildReady && !Rescan)
#ifndef X_NOT_POSIX
sigsuspend(&omask);
#else
sigpause (omask);
#endif
ChildReady = 0;
#ifndef X_NOT_POSIX
sigprocmask(SIG_SETMASK, &omask, (sigset_t *)NULL);
#else
sigsetmask (omask);
#endif
while ((pid = waitpid (-1, &status, WNOHANG)) > 0)
#endif
{
Debug ("Manager wait returns pid: %d sig %d core %d code %d\n",
pid, waitSig(status), waitCore(status), waitCode(status));
if (autoRescan)
RescanIfMod ();
/* SUPPRESS 560 */
if ((d = FindDisplayByPid (pid))) {
d->pid = -1;
switch (waitVal (status)) {
case UNMANAGE_DISPLAY:
Debug ("Display exited with UNMANAGE_DISPLAY\n");
StopDisplay (d);
break;
case OBEYSESS_DISPLAY:
d->startTries = 0;
Debug ("Display exited with OBEYSESS_DISPLAY\n");
if (d->displayType.lifetime != Permanent ||
d->status == zombie)
StopDisplay (d);
else
RestartDisplay (d, FALSE);
break;
case OPENFAILED_DISPLAY:
Debug ("Display exited with OPENFAILED_DISPLAY, try %d of %d\n",
d->startTries, d->startAttempts);
LogError ("Display %s cannot be opened\n", d->name);
/*
* no display connection was ever made, tell the
* terminal that the open attempt failed
*/
#ifdef XDMCP
if (d->displayType.origin == FromXDMCP)
SendFailed (d, "Cannot open display");
#endif
if (d->displayType.origin == FromXDMCP ||
d->status == zombie ||
++d->startTries >= d->startAttempts)
{
LogError ("Display %s is being disabled\n", d->name);
StopDisplay (d);
}
else
{
RestartDisplay (d, TRUE);
}
break;
case RESERVER_DISPLAY:
d->startTries = 0;
Debug ("Display exited with RESERVER_DISPLAY\n");
if (d->displayType.origin == FromXDMCP || d->status == zombie)
StopDisplay(d);
else
RestartDisplay (d, TRUE);
{
Time_t Time;
time(&Time);
Debug("time %i %i\n",Time,d->lastCrash);
if (d->lastCrash &&
((Time - d->lastCrash) < XDM_BROKEN_INTERVAL)) {
Debug("Server crash frequency too high:"
" removing display %s\n",d->name);
LogError("Server crash rate too high:"
" removing display %s\n",d->name);
#if !defined(ARC4_RANDOM) && !defined(DEV_RANDOM)
AddTimerEntropy();
#endif
RemoveDisplay (d);
} else
d->lastCrash = Time;
}
break;
case waitCompose (SIGTERM,0,0):
Debug ("Display exited on SIGTERM, try %d of %d\n",
d->startTries, d->startAttempts);
if (d->displayType.origin == FromXDMCP ||
d->status == zombie ||
++d->startTries >= d->startAttempts) {
LogError ("Display %s is being disabled\n", d->name);
StopDisplay(d);
} else
RestartDisplay (d, TRUE);
break;
case REMANAGE_DISPLAY:
d->startTries = 0;
Debug ("Display exited with REMANAGE_DISPLAY\n");
/*
* XDMCP will restart the session if the display
* requests it
*/
if (d->displayType.origin == FromXDMCP || d->status == zombie)
StopDisplay(d);
else
RestartDisplay (d, FALSE);
break;
default:
Debug ("Display exited with unknown status %d\n", waitVal(status));
LogError ("Unknown session exit code %d from process %d\n",
waitVal (status), pid);
StopDisplay (d);
break;
}
}
/* SUPPRESS 560 */
else if ((d = FindDisplayByServerPid (pid)))
{
d->serverPid = -1;
switch (d->status)
{
case zombie:
Debug ("Zombie server reaped, removing display %s\n", d->name);
RemoveDisplay (d);
break;
case phoenix:
Debug ("Phoenix server arises, restarting display %s\n", d->name);
d->status = notRunning;
break;
case running:
Debug ("Server for display %s terminated unexpectedly, status %d %d\n", d->name, waitVal (status), status);
LogError ("Server for display %s terminated unexpectedly: %d\n", d->name, waitVal (status));
if (d->pid != -1)
{
Debug ("Terminating session pid %d\n", d->pid);
TerminateProcess (d->pid, SIGTERM);
}
break;
case notRunning:
Debug ("Server exited for notRunning session on display %s\n", d->name);
break;
}
}
else
{
Debug ("Unknown child termination, status %d\n", waitVal (status));
}
}
StartDisplays ();
}
static void
CheckDisplayStatus (struct display *d)
{
if (d->displayType.origin == FromFile)
{
switch (d->state) {
case MissingEntry:
StopDisplay (d);
break;
case NewEntry:
d->state = OldEntry;
case OldEntry:
if (d->status == notRunning)
StartDisplay (d);
break;
}
}
}
static void
StartDisplays (void)
{
ForEachDisplay (CheckDisplayStatus);
}
static void
SetWindowPath(struct display *d)
{
/* setting WINDOWPATH for clients */
Atom prop;
Atom actualtype;
int actualformat;
unsigned long nitems;
unsigned long bytes_after;
unsigned char *buf;
const char *windowpath;
char *newwindowpath;
unsigned long num;
char nums[10];
int numn;
prop = XInternAtom(d->dpy, "XFree86_VT", False);
if (prop == None) {
fprintf(stderr, "no XFree86_VT atom\n");
return;
}
if (XGetWindowProperty(d->dpy, DefaultRootWindow(d->dpy), prop, 0, 1,
False, AnyPropertyType, &actualtype, &actualformat,
&nitems, &bytes_after, &buf)) {
fprintf(stderr, "no XFree86_VT property\n");
return;
}
if (nitems != 1) {
fprintf(stderr, "%lu items in XFree86_VT property!\n", nitems);
XFree(buf);
return;
}
switch (actualtype) {
case XA_CARDINAL:
case XA_INTEGER:
case XA_WINDOW:
switch (actualformat) {
case 8:
num = (*(uint8_t *)(void *)buf);
break;
case 16:
num = (*(uint16_t *)(void *)buf);
break;
case 32:
num = (*(uint32_t *)(void *)buf);
break;
default:
fprintf(stderr, "format %d in XFree86_VT property!\n", actualformat);
XFree(buf);
return;
}
break;
default:
fprintf(stderr, "type %lx in XFree86_VT property!\n", actualtype);
XFree(buf);
return;
}
XFree(buf);
windowpath = getenv("WINDOWPATH");
numn = snprintf(nums, sizeof(nums), "%lu", num);
if (!windowpath) {
newwindowpath = malloc(numn + 1);
sprintf(newwindowpath, "%s", nums);
} else {
newwindowpath = malloc(strlen(windowpath) + 1 + numn + 1);
sprintf(newwindowpath, "%s:%s", windowpath, nums);
}
if (d->windowPath)
free(d->windowPath);
d->windowPath = newwindowpath;
}
void
StartDisplay (struct display *d)
{
pid_t pid;
Debug ("StartDisplay %s\n", d->name);
LoadServerResources (d);
if (d->displayType.location == Local)
{
/* don't bother pinging local displays; we'll
* certainly notice when they exit
*/
d->pingInterval = 0;
if (d->authorize)
{
Debug ("SetLocalAuthorization %s, auth %s\n",
d->name, d->authNames[0]);
SetLocalAuthorization (d);
/*
* reset the server after writing the authorization information
* to make it read the file (for compatibility with old
* servers which read auth file only on reset instead of
* at first connection)
*/
if (d->serverPid != -1 && d->resetForAuth && d->resetSignal)
kill (d->serverPid, d->resetSignal);
}
if (d->serverPid == -1 && !StartServer (d))
{
LogError ("Server for display %s can't be started, session disabled\n", d->name);
RemoveDisplay (d);
return;
}
}
else
{
/* this will only happen when using XDMCP */
if (d->authorizations)
SaveServerAuthorizations (d, d->authorizations, d->authNum);
}
if (!nofork_session)
pid = fork ();
else
pid = 0;
switch (pid)
{
case 0:
if (!nofork_session) {
CleanUpChild ();
(void) Signal (SIGPIPE, SIG_IGN);
}
LoadSessionResources (d);
SetAuthorization (d);
if (!WaitForServer (d))
exit (OPENFAILED_DISPLAY);
SetWindowPath(d);
#ifdef XDMCP
if (d->useChooser)
RunChooser (d);
else
#endif
ManageSession (d);
exit (REMANAGE_DISPLAY);
case -1:
break;
default:
Debug ("pid: %d\n", pid);
d->pid = pid;
d->status = running;
break;
}
}
static void
TerminateProcess (pid_t pid, int signal)
{
kill (pid, signal);
#ifdef SIGCONT
kill (pid, SIGCONT);
#endif
}
/*
* transition from running to zombie or deleted
*/
void
StopDisplay (struct display *d)
{
if (d->serverPid != -1)
d->status = zombie; /* be careful about race conditions */
if (d->pid != -1)
TerminateProcess (d->pid, SIGTERM);
if (d->serverPid != -1)
TerminateProcess (d->serverPid, d->termSignal);
else
RemoveDisplay (d);
}
/*
* transition from running to phoenix or notRunning
*/
static void
RestartDisplay (struct display *d, int forceReserver)
{
if (d->serverPid != -1 && (forceReserver || d->terminateServer))
{
TerminateProcess (d->serverPid, d->termSignal);
d->status = phoenix;
}
else
{
d->status = notRunning;
}
}
static FD_TYPE CloseMask;
static int max;
void
RegisterCloseOnFork (int fd)
{
FD_SET (fd, &CloseMask);
if (fd > max)
max = fd;
}
void
ClearCloseOnFork (int fd)
{
FD_CLR (fd, &CloseMask);
if (fd == max) {
while (--fd >= 0)
if (FD_ISSET (fd, &CloseMask))
break;
max = fd;
}
}
void
CloseOnFork (void)
{
int fd;
for (fd = 0; fd <= max; fd++)
if (FD_ISSET (fd, &CloseMask))
{
close (fd);
}
FD_ZERO (&CloseMask);
max = 0;
}
static int pidFd;
static FILE *pidFilePtr;
static int
StorePid (void)
{
int oldpid;
if (pidFile[0] != '\0') {
pidFd = open (pidFile, O_RDWR);
if (pidFd == -1 && errno == ENOENT)
pidFd = open (pidFile, O_RDWR|O_CREAT, 0666);
if (pidFd == -1 || !(pidFilePtr = fdopen (pidFd, "r+")))
{
LogError ("process-id file %s cannot be opened\n",
pidFile);
return -1;
}
if (fscanf (pidFilePtr, "%d\n", &oldpid) != 1)
oldpid = -1;
fseek (pidFilePtr, 0l, 0);
if (lockPidFile)
{
#ifdef F_SETLK
#ifndef SEEK_SET
#define SEEK_SET 0
#endif
struct flock lock_data;
lock_data.l_type = F_WRLCK;
lock_data.l_whence = SEEK_SET;
lock_data.l_start = lock_data.l_len = 0;
if (fcntl(pidFd, F_SETLK, &lock_data) == -1)
{
if (errno == EAGAIN)
return oldpid;
else
return -1;
}
#else
#ifdef LOCK_EX
if (flock (pidFd, LOCK_EX|LOCK_NB) == -1)
{
if (errno == EWOULDBLOCK)
return oldpid;
else
return -1;
}
#else
if (lockf (pidFd, F_TLOCK, 0) == -1)
{
if (errno == EACCES)
return oldpid;
else
return -1;
}
#endif
#endif
}
fprintf (pidFilePtr, "%5ld\n", (long)getpid ());
(void) fflush (pidFilePtr);
RegisterCloseOnFork (pidFd);
}
return 0;
}
#if 0
void
UnlockPidFile (void)
{
if (lockPidFile)
#ifdef F_SETLK
{
struct flock lock_data;
lock_data.l_type = F_UNLCK;
lock_data.l_whence = SEEK_SET;
lock_data.l_start = lock_data.l_len = 0;
(void) fcntl(pidFd, F_SETLK, &lock_data);
}
#else
#ifdef F_ULOCK
lockf (pidFd, F_ULOCK, 0);
#else
flock (pidFd, LOCK_UN);
#endif
#endif
close (pidFd);
fclose (pidFilePtr);
}
#endif
#ifndef HAS_SETPROCTITLE
void SetTitle (char *name, ...)
{
#ifndef NOXDMTITLE
char *p = Title;
int left = TitleLen;
char *s;
va_list args;
va_start(args,name);
*p++ = '-';
--left;
s = name;
while (s)
{
while (*s && left > 0)
{
*p++ = *s++;
left--;
}
s = va_arg (args, char *);
}
while (left > 0)
{
*p++ = ' ';
--left;
}
va_end(args);
#endif
}
#endif