| 1 | .\" $Id: dm.8,v 1.8 1999-01-22 23:16:12 ghudson Exp $ |
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| 2 | .TH DM 8 "30 April 1994" |
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| 3 | .ds ]W MIT Project Athena |
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| 4 | .SH NAME |
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| 5 | dm \- X display manager |
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| 6 | .SH SYNOPSIS |
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| 7 | dm \fIconfigfile logintty\fR [-noconsole] \fIconsoletty\fR |
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| 8 | .SH DESCRIPTION |
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| 9 | |
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| 10 | \fIDm\fR is intended to be run by \fIinit\fR to startup the X server, |
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| 11 | the X console, and X login. It will read out of the specified config |
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| 12 | file the command lines for these three processes. |
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| 13 | .PP |
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| 14 | This file consists of lines containing the program name, whitespace, |
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| 15 | and the commandline for the program. The program names recognized are |
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| 16 | \fBdm\fB, \fBX\fR, \fBconsole\fR, and \fBlogin\fR. Everything from a |
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| 17 | hash mark to the end-of-line will be ignored as a comment. \fIDm\fR |
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| 18 | recognizes one command line option from this file, -display. If it |
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| 19 | is not specified, \fIdm\fR will default to :0. |
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| 20 | .PP |
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| 21 | The X server will be started first, using the SIGUSR1 handshake |
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| 22 | present in X11R4. For security reasons, \fIdm\fR will then |
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| 23 | immediately open the X display and remove all hosts from the server's |
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| 24 | access control list, unless the file /etc/X*.hosts exists and has |
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| 25 | nonzero length (* represents the display number). This serves to |
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| 26 | prevent any possible connections from other than the Unix domain socket. |
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| 27 | \fIDm\fR will keep this connection open to prevent the X server from |
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| 28 | inadvertently resetting should the user at some point have closed all |
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| 29 | X connections temporarily. Next the console will be started, reading |
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| 30 | from the master side of the pseudo-tty specified as the |
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| 31 | \fIlogintty\fR. If \fIlogintty\fR is already in use, another |
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| 32 | pseudo-tty will be chosen. Then the login will be started, with stdin |
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| 33 | set to \fI/dev/null\fR and stdout and stderr set to \fIlogintty\fR. |
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| 34 | The display manager then waits for a change in the status of its |
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| 35 | children or a signal to arrive. If the display manager encounters |
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| 36 | errors while starting up, it will initiate a console login. |
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| 37 | .PP |
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| 38 | If the console exits, another one will be started. If the X server or |
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| 39 | xlogin exit, the display manager will clean up and exit. This |
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| 40 | includes a call to \fIal_acct_revert(3)\fR to clean up the user's login |
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| 41 | session if necessary. If xlogin exits with status 2, it is requesting |
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| 42 | that a raw console login be started. If the display manager receives |
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| 43 | SIGFPE, it will kill its children and sleep forever (this is a way to |
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| 44 | shutdown the display during updates). |
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| 45 | .PP |
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| 46 | If the \fB-noconsole\fR switch is given, it will not do the special |
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| 47 | console handling. This is necessary if more than one display manager |
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| 48 | is running on a machine. |
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| 49 | .SH FILES |
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| 50 | /etc/utmp, /usr/adm/wtmp, /etc/passwd, /etc/ptmp, /etc/X*.hosts, |
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| 51 | /var/athena/X*.pid, /var/athena/console.pid, /var/athena/dm.pid, /dev/mouse, |
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| 52 | /dev/cons, /var/athena/console.log, /dev/console |
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| 53 | |
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| 54 | .SH "SEE ALSO" |
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| 55 | Xserver(1), console(8), xlogin(8), config_console(1), init(8), |
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| 56 | al_acct_revert(3) |
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| 57 | |
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| 58 | .SH AUTHOR |
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| 59 | Mark Rosenstein, MIT Project Athena |
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| 60 | .br |
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| 61 | Copyright (c) 1990 Massachusetts Institute of Technology |
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| 62 | |
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| 63 | .SH BUGS |
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| 64 | Sometimes the console does not revert back to the real console when a |
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| 65 | console login is requested. |
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| 66 | |
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| 67 | Sometimes it is necessary to press SHIFT, CONTROL, and/or META before |
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| 68 | keys work normally when a console login is requested. |
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