GETTY_PS 2.0.7d for Linux 1.0 and higher ---------------------------------------- OVERVIEW This is my third major release of getty_ps for Linux. It is intended for Linux kernels at version 1.0 or higher (although it should function correctly on 0.99.15 kernels as well). There are many modifications to the source. Some changes in the serial drivers prompted this release. vhangup() is handled correctly now. Also, thanks to Ted's new serial drivers, monitoring for other processes that have possibly messed up the line is much easier now. The following bugs have been fixed: * SCHED is cleaned up and now handles timezones and daylight savings time correctly * utmp logging should work correctly now, regardless of which init program is being used * RINGBACK has slightly more sane default parameters The following features have been added: * error and debug logging are handled with syslog by default (you can still log to a file if you must) * users of ifmail (fidonet) should be able to run ifmail without patching the getty source * debugging and error output is more verbose and easier to understand This release is intended as a maintenance release only. The next version of this package will be quite a bit different in most aspects. There are some useful features coming up (such as fax- receive and call-back). If you have any problems setting up the package, questions about mod- ifications, or suggestions for additional features, feel free to mail me. I am more than happy to help out. When you mail me with problem reports, please be sure to include full debugging output from getty that illustrates the problem; I am pretty much helpless without it. As always, I would love to hear any bug reports. Kris Gleason gleasokr@boulder.colorado.edu CONTENTS 1. Brief explination of serial drivers under Linux (0.99.15 and up) 2. Compiling and installing the programs 3. Setting up the configuration files 4. Troubleshooting 5. Credits, Thanks, Etc... 1. SERIAL DRIVERS The serial drivers have changed again as of 0.99.15. If you are not too interested in knowing how the serial ports work, you can probably skim over this section. The basic idea behind Linux serial drivers is that callin and callout devices should not try to use the same line at the same time. In the past, this was accomplished by juggling lockfiles. The new scheme takes care of the problem in the kernel. Instead of one modem device, there are now two: a callin device, named /dev/ttyS# (where # is the port number), and a callout device, named /dev/cua# (again, # = port number). The callin devices are used by programs like getty; the callout devices are used by programs like Seyon and Kermit. If you don't have the callout devices in /dev, you create them with the mknod command. They are character devices, major number 5, minor number same as the corresponding callin device. Consult the Linux Device List for more information about creating the /dev entries. So how does it work? Simple... Suppose that kermit wants to open /dev/cua1 for a callout session. The kernel allows the line to be open if and only if no other program currently has the corresponding /dev/ttyS1 line open; if it does, the error EBUSY is returned in errno. The /dev/ttyS1 line is a bit more complicated. By default, the device 'blocks' on open. This means that the program will be stopped until the device is clear to open. For the device to be clear, two things must be true: no process can be using the corresponding /dev/cua1 line, and the carrier detect line of the serial port must be high. While the device is blocking, it is not busy, so callout devices can use the line. In other words, if getty is running on /dev/ttyS1, as long as no incoming calls open the line (causing the carrier to go high), other programs are free to use the line. Blocking can be dis- abled by setting the O_NDELAY flag to the open system call. In this case, carrier detect is not needed to open the line; however, if /dev/ttyS1 is busy, EBUSY is still returned in errno and the open fails. Finally, a blocking open will return EAGAIN in errno if another process closes the corresponding callout device. This allows getty to easily monitor the serial line, and reinitialize if another program might have changed serial port parameters (or modem parameters). 2. COMPILING AND INSTALLING THE PROGRAMS Two binaries are the product of this package: getty and uugetty. The only difference between getty and uugetty is that uugetty checks and creates lockfiles. Uugetty should be used on any bidirectional line (modems, for example). Getty should be used on unidirectional lines (virtual consoles, dumb terminals). Everything should be all set to compile on any 'normal' Linux box (whatever that is). Just untar the sources (which I assume you've done if you're reading this), edit the Makefile to reflect your local configuration, favorite linking flags, etc... Also, edit the file tune.h, and change this to your liking. Most everything is compiled in by default, so you probably don't need to tinker with this too much. Do a make depend; make all to build the programs. I have also included binaries of getty and uugetty; these files were compiled with gcc 2.5.8, and linked with libc.so.4.5.21. If your library is older, you will have to do the compile yourself (or grab the new library). After the sources are compiled, MAKE A BACKUP COPY OF YOUR EXISTING WORKING GETTY PROGRAM! I cannot stress this enough. There is a good chance that you will not have things configured correctly the first time around, and will not be able to log into your machine. This is also probably a good time to get one of those bootable rootdisks. In any case, be sure you can boot your system in single user mode before you install anything. I like my getty binaries in /etc. If you want yours in /bin or /sbin, edit the Makefile. Make install to copy the binaries into the correct directories. By default, your old getty and uugetty programs are saved under getty- and uugetty-. After everything is running smoothly, you can remove these backup files. 3. SETING UP CONFIGURATION FILES After you install the binaries AND BEFORE YOU LOGOUT/SHUTDOWN you must edit the file /etc/inittab. The argument format for getty_ps is: getty tty speed [terminal-type] uugetty tty speed [terminal-type] 'Tty' is the line to run on (without the /dev). Speed is the line speed as defined in /etc/gettydefs. This argument must match the first field of one of the lines in /etc/gettydefs (see gettydefs(4) man page). The optional terminal-type is the expected type of terminal to be found at the other end. I set this to console for vt's and vt100 for serial lines. Here is the relevant portion of my /etc/inittab file: 1:123:respawn:/etc/getty tty1 VC console ... s2:23:respawn:/etc/uugetty ttys2 2400 vt100 Be sure the format of the inittab entries you create are consistent with the version of init you are using. This example works with a SYS-V compatible init program. If you are using simpleinit, the format is different. You will want to change one of the lines to use your OLD WORKING getty (named getty- if you used make install) until everything is stable. Next, you want to create the configuration files. The file /etc/gettydefs must exist for proper operation. See the man page for gettydefs(5) for the format of this file. There is an example under the examples directory that you can use to get started. You will also want to set up /etc/syslog.conf to properly log getty error and debug output. By default, getty logs to facility LOG_AUTH. Errors are sent with priority LOG_ERR, and debugging output is sent with priority LOG_DEBUG. If you don't like syslog, make the proper adjustments to tune.h. Here are the relevant lines from my /etc/syslog.conf: auth.warning; /usr/adm/auth.log auth.debug; /usr/adm/getty.debug.log Finally, you want to create configuration files for the individual lines. These are kept in /etc/default. If you are running getty on tty2, the configuration file is /etc/default/getty.tty2; for uugetty on ttyS0, /etc/default/uugetty.ttyS0. Also, if you want the same file for all instances of getty or uugetty, you can make the file /etc/default/getty or /etc/default/uugetty. Example configuration files are under the examples directory. See the getty(1) manual page for more information on this file. These configuration files are optional, so your system won't crash if you don't have them, and no configuration files are needed to run getty on a virtual console or dumb terminal (though you can still have them if you want). The main purpose of the configuration files is to configure your modem correctly. If you think you have everything right, reboot your system (you do have a _working_ bootable floppy, right? I thought so). If you can log into your system on the consoles you set to use the new getty, everything is working fine (at least on the consoles). Next, after you have edited the configuration file for your modem's tty line, go over to a friend's house and try to call up. If you have a 14400 baud Hayes modem, the files I have included should drop right in and work; otherwise they might need some editing. 4. TROUBLESHOOTING So, what could possibly go wrong? In my experience, the major source of confusion with getty_ps has been setting up the chat sequences correctly. Failing chat sequences will cause init to produce errors like 'respawning too fast'. If your modem is not responding as expected to the INIT/OFF/CONNECT chat sequences, getty will be continuously respawning. Check your log files; if you have have lots of lines that say INIT sequence failed, this is the problem. Check your /etc/default/* files. You can turn on debugging of the init sequence by adding the following line to your defaults file: DEBUG=010 or, alternatly, add the -D010 flag to the entry in /etc/inittab. This will log some helpful information to syslog. Read this for clues as to what might be going wrong. If you get CONNECT sequence failed, then the CONNECT line is to blame. Debug this line the same way. If you have other problems. Turn on full debugging: DEBUG=777 and read the debugging log. If you can't make heads or tails of it, mail it to me and I'll see what I can do with it (after all... it may be a bug). I don't know anything about other types of modems, so if you have modem specific questions, I probably can't help much. 5. CREDITS, ETC... Special thanks to all of these people: Paul Sutcliffe ... original author Steve Robbins ... former maintanier of getty_ps Michael Haardt ... SYSV init support Theodore Tso ... for a valuable discussion of the new serial drivers Shane Alderton ... for the ringback patches Julian Cowley ... for helping with the transition to the 0.99.15 serial drivers Dr. G.W. Wettstein ... for syslog patches Eugene Crosser ... fidonet patches I have included all of the original documentation from this package under the OLD directory. You might find it useful. If you find that this file is missing something, please let me know. I've tried to be as complete as possible without writing a book, but I have been known to screw up in the past. Good Luck. Kris Gleason gleasokr@boulder.colorado.edu