/* $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 3.24 2004/01/10 21:26:29 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 #ifdef X_POSIX_C_SOURCE #define _POSIX_C_SOURCE X_POSIX_C_SOURCE #include #undef _POSIX_C_SOURCE #else #if defined(X_NOT_POSIX) || defined(_POSIX_SOURCE) #include #else #define _POSIX_SOURCE #include #undef _POSIX_SOURCE #endif #endif #ifdef __NetBSD__ #include #endif #ifndef sigmask #define sigmask(m) (1 << ((m - 1))) #endif # include # include # include # include #ifndef F_TLOCK #ifndef X_NOT_POSIX # include #endif #endif #if defined(SVR4) && !defined(SCO) && !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 (int 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 int parent_pid = -1; /* PID of parent xdm process */ int main (int argc, char **argv) { int oldpid, 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 /* * 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) { int 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 #ifndef X_NOT_POSIX while ((pid = waitpid (-1, &status, WNOHANG)) > 0) #else while ((pid = wait3 (&status, WNOHANG, (struct rusage *) 0)) > 0) #endif #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); } void StartDisplay (struct display *d) { int 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); #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 (int 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