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diff --git a/sag-0.6.1-www/Invisible/sag-0.6/node80.html b/sag-0.6.1-www/Invisible/sag-0.6/node80.html new file mode 100644 index 0000000..60dae28 --- /dev/null +++ b/sag-0.6.1-www/Invisible/sag-0.6/node80.html @@ -0,0 +1,71 @@ +<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN"> +<!--Converted with LaTeX2HTML 96.1-h (September 30, 1996) by Nikos Drakos (nikos@cbl.leeds.ac.uk), CBLU, University of Leeds --> +<HTML> +<HEAD> +<TITLE>Logins via terminals</TITLE> +<META NAME="description" CONTENT="Logins via terminals"> +<META NAME="keywords" CONTENT="sag"> +<META NAME="resource-type" CONTENT="document"> +<META NAME="distribution" CONTENT="global"> +<LINK REL=STYLESHEET HREF="sag.css"> +</HEAD> +<BODY LANG="EN" > + <A NAME="tex2html1321" HREF="node81.html"><IMG WIDTH=37 HEIGHT=24 ALIGN=BOTTOM ALT="next" SRC="./next_motif.gif"></A> <A NAME="tex2html1319" HREF="node79.html"><IMG WIDTH=26 HEIGHT=24 ALIGN=BOTTOM ALT="up" SRC="./up_motif.gif"></A> <A NAME="tex2html1313" HREF="node79.html"><IMG WIDTH=63 HEIGHT=24 ALIGN=BOTTOM ALT="previous" SRC="./previous_motif.gif"></A> <A NAME="tex2html1323" HREF="node1.html"><IMG WIDTH=65 HEIGHT=24 ALIGN=BOTTOM ALT="contents" SRC="./contents_motif.gif"></A> <A NAME="tex2html1324" HREF="node114.html"><IMG WIDTH=43 HEIGHT=24 ALIGN=BOTTOM ALT="index" SRC="./index_motif.gif"></A> <BR> +<B> Next:</B> <A NAME="tex2html1322" HREF="node81.html">Logins via the network</A> +<B>Up:</B> <A NAME="tex2html1320" HREF="node79.html">Logging In And Out</A> +<B> Previous:</B> <A NAME="tex2html1314" HREF="node79.html">Logging In And Out</A> +<BR> <P> +<H1><A NAME="SECTION00910000000000000000">Logins via terminals</A></H1> +<P> + Figure <A HREF="node80.html#figterminallogins">8.1</A> shows how logins happen + via terminals. First, <tt>init</tt><A NAME="2589"> </A> makes sure there is a + <tt>getty</tt><A NAME="2591"> </A> program for the terminal connection (or + console). <tt>getty</tt><A NAME="2593"> </A> listens at the terminal and waits for + the user to notify that he is ready to login in (this usually + means that the user must type something). When it notices a + user, <tt>getty</tt><A NAME="2595"> </A> outputs + a welcome message (stored in <tt>/etc/issue</tt><A NAME="2597"> </A>), and prompts for + the username, and finally runs the <tt>login</tt><A NAME="2599"> </A> program. + <tt>login</tt><A NAME="2601"> </A> gets the username as a parameter, and prompts the + user for the password. If these match, <tt>login</tt><A NAME="2603"> </A> + starts the shell configured for the user; else it just exits + and terminates the process (perhaps after giving the user + another chance at entering the username and password). + <tt>init</tt><A NAME="2605"> </A> notices that the + process terminated, and starts a new <tt>getty</tt><A NAME="2607"> </A> for the + terminal. +<P> +<P><A NAME="2586"> </A><A NAME="figterminallogins"> </A><IMG WIDTH=461 HEIGHT=734 ALIGN=BOTTOM ALT="figure2514" SRC="img13.gif"><BR> +<STRONG>Figure 8.1:</STRONG> Logins via terminals: the interaction of <tt>init</tt><A NAME="2609"> </A>, <tt>getty</tt><A NAME="2611"> </A>, + <tt>login</tt><A NAME="2613"> </A>, and the shell.<BR> +<P> +<P> + Note that the only new process is the one created by <tt>init</tt><A NAME="2615"> </A> + (using the <tt>fork</tt><A NAME="2617"> </A> system call); + <tt>getty</tt><A NAME="2619"> </A> and <tt>login</tt><A NAME="2621"> </A> only replace the program running + in the process (using the <tt>exec</tt><A NAME="2623"> </A> system call). +<P> + A separate program, for noticing the user, is needed for serial + lines, since it can be (and traditionally was) complicated to + notice when a terminal becomes active. <tt>getty</tt><A NAME="2625"> </A> also adapts + to the speed and other settings of the connection, which is + important especially for dial-in connections, where these + parameters may change from call to call. +<P> + There are several versions of <tt>getty</tt><A NAME="2627"> </A> and <tt>init</tt><A NAME="2629"> </A> + in use, all with their good and bad points. It is a good idea + to learn about the versions on your system, and also about the + other versions (you could use the Linux Software Map to search + them). If you don't have dial-in's, you probably don't have to + worry about <tt>getty</tt><A NAME="2631"> </A>, but <tt>init</tt><A NAME="2633"> </A> is still important. +<P> +<HR><A NAME="tex2html1321" HREF="node81.html"><IMG WIDTH=37 HEIGHT=24 ALIGN=BOTTOM ALT="next" SRC="./next_motif.gif"></A> <A NAME="tex2html1319" HREF="node79.html"><IMG WIDTH=26 HEIGHT=24 ALIGN=BOTTOM ALT="up" SRC="./up_motif.gif"></A> <A NAME="tex2html1313" HREF="node79.html"><IMG WIDTH=63 HEIGHT=24 ALIGN=BOTTOM ALT="previous" SRC="./previous_motif.gif"></A> <A NAME="tex2html1323" HREF="node1.html"><IMG WIDTH=65 HEIGHT=24 ALIGN=BOTTOM ALT="contents" SRC="./contents_motif.gif"></A> <A NAME="tex2html1324" HREF="node114.html"><IMG WIDTH=43 HEIGHT=24 ALIGN=BOTTOM ALT="index" SRC="./index_motif.gif"></A> <BR> +<B> Next:</B> <A NAME="tex2html1322" HREF="node81.html">Logins via the network</A> +<B>Up:</B> <A NAME="tex2html1320" HREF="node79.html">Logging In And Out</A> +<B> Previous:</B> <A NAME="tex2html1314" HREF="node79.html">Logging In And Out</A> +<P><ADDRESS> +<I>Lars Wirzenius <BR> +Sat Nov 15 02:32:11 EET 1997</I> +</ADDRESS> +</BODY> +</HTML> |