pbickers@tamaluit.phys.uidaho.edu (Paul Bickerstaff) (06/07/91)
I have a minor problem which I can't fathom: We have a
Magnum 3000 running RISCos 4.51 and I've put a Practical Peripherals
(Hayes compatible) modem on one of the ports of a 16-port Digiboard
card (RJ45 - DB25 straight through cable). I've set uugetty running
on this port (/etc/inittab entry):
d3:234:respawn:/usr/lib/uucp/uugetty -h -t 60 -r ttyd3 dm2400 none LDISC0
and /etc/gettydefs entry:
dm2400# B2400 CLOCAL MDMBUF # B2400 CLOCAL MDMBUF SANE TAB3
#\r\n\n$HOSTNAME login: #dm2400
(and have tried HUPCL here without it curing the problem).
The problem is that the port gets locked and stays locked. More precisely,
the first time someone dials in (after I change things) the port does not
lock (!! which I'm sure it should) but only locks when the user exits and
stays locked thereafter. (At least the lock file only appears in
/usr/spool/locks
when the user exits and stays there until I step in and remove it.) My belief
is that the port should be locked when in use and not otherwise.
Now this is only a minor problem because the modem is desired mainly for
dial-ins and it appears to work fine for this purpose despite the above
behaviour (though see the remarks below on ownership). However, I would
like the modem available for dialing out, if desired, and besides, the
following
repeated mail messages to root are driving me nuts:
Subject: uu-status
Apparently-To: uucp
LCK..ttyd3: 3443
F S UID PID PPID C PRI NI ADDR SZ WCHAN STIME TTY
TIME COMD
10 S root 3443 1 0 28 20 801103e8 71 c013f740
22:35:30 tty
d3 0:00 /usr/lib/uucp/uugetty -h -t 60 -r t
I know that if I were to be satisfied with just dial-ins I could just
run getty on
the port but I feel that would be an unsatisfying solution :-) (if it's
a solution
at all -- I have n't tried it.)
Some further info:
the device ownership and permissions are being interfered with; currently
(with the thing locked) we have:
% ls -l /dev/ttyd3
crw--w--w- 1 uucp theory 32, 3 Jun 6 08:29 /dev/ttyd3
I initially set the permissions to 664 and the group to daemon, in accordance
with recommended (Nemeth et al.) practice. Theory is the group of the
person who last logged in via the modem. (Don't know what happens if
somebody in another group trys to dial-in. The problem is not likely to
arise :-) )
I also have added these entries to the Devices file:
Direct ttyd2 - 1200 direct #ups
Direct ttyd3 - 2400 direct
#ACU cul3 cua3 2400 hayes
#ACU cul3 cua3 1200 hayes
ACU ttyd3 - 2400 hayes
but don't think that is relevant to the present problem.
If anybody knows what I'm overlooking I'd sure appreciate the magic
recipe.
Many thanks in advance,
Paul
Paul Bickerstaff Internet: pbickers@tamaluit.phys.uidaho.edu
Physics Dept., Univ. of Idaho Phone: (208) 885 6809
Moscow ID 83843, USA FAX: (208) 885 6173trevc@tecate.mips.com (Trevor Cotton) (06/07/91)
In article <1991Jun06.190435.24051@groucho>, pbickers@tamaluit.phys.uidaho.edu (Paul Bickerstaff) writes: |> I have a minor problem which I can't fathom: We have a |> Magnum 3000 running RISCos 4.51 and I've put a Practical Peripherals |> (Hayes compatible) modem on one of the ports of a 16-port Digiboard |> card (RJ45 - DB25 straight through cable). I've set uugetty running |> on this port (/etc/inittab entry): |> The following explains how to correctly set up uugetty/cu. One thing it does not mention is permissions. The very first time you try to use the line, you should set the permissions to 666. After that, uugetty, cu and login will manage the permissions and ownerships, and you should not need to ( and, in fact, you should not ) change them again. Guidelines for setting up a bi-directional modem on a MIPS box -------------------------------------------------------------- 1) The serial port used MUST have modem control enabled ( that is, CLOCAL must be off ). The easiest way to do this is to use a device name with a minor number > 128. All the current MIPS serial drivers will default to using modem control on a serial line if the device minor number is > 128 and the kopt _riscos_ttys_default_clocal is set to 0 ( the default ) . So, for example, if we wanted to connect the modem to the second serial port on an RC3240 machine, we would use the device /dev/ttym1. Not all MIPS serial ports support modem control. Refer to section 2.7.8 of the RISCos 4.50 Release Notes for details on which ports support modem control. Please note that if CLOCAL is off, MDMBUF should NOT be set on. These are mutually exclusive. The following information was in the RISCos 4.0 Release notes, but was omitted from the 4.5 Release notes. Here it is again :- "...In addition, the kopt _riscos_ttys_default_clocal has been added, with default value of ``enabled'', to retain backward compatibility with RISC/os 3.10. If enabled, terminal lines default to CLOCAL enabled for minor devices numbered 0 through 127, and CLOCAL disabled for minor devices numbered 128 through 255. If the kopt is disabled, the above CLOCAL defaults are reversed, to more closely match the behavior of other UNIX systems. (MIPS has adopted the Sun convention that terminal minor device i, 0<=i<=127, is the same as terminal minor device i+128, except that the CLOCAL default is inverted for one, relative to the other.) " 2) The modem that is connected must be set up so that it only raises DCD when a connection has been established to another modem. This is normally the default for modems. The reasons for 1) and 2) above are : -uugetty opens the serial line, and then sleeps waiting for DCD to come true. Once DCD comes true, uugetty will attempt to create a lockfile in the /usr/spool/locks directory, and then issue a login prompt. If a lockfile already exists ( indicating cu is already using the line ) uugetty will go back to sleep. -cu always opens the line without waiting for DCD, and so can use the same device name. When cu starts up, it tries to create a lockfile in /usr/spool/locks. If one already exists, and the process that created that lock file is still running, cu will exit. 3) Cabling is very important, and differs depending on what type of MIPS serial port is being used. Detailed information is printed in the RISCos 4.50 Release Notes, section 2.7.6. The aim is to make sure that as well as TX, RX and GND being correct, DCD from the modem is connected to the relevant input pin on the MIPS port, and that DTR out from the MIPS is connected to the correct modem input pin. So, for example, to connect a modem to the second serial port on an RC3240 the cable to use would be MIPS ttym1 modem 2 ------------- 2 3 ------------- 3 5 ------------- 8 7 ------------- 7 20 ------------- 20 To connect a modem to a Digiboard port, the following cable should be used: MIPS ttydm?? modem 2 ------------ 2 3 ------------ 3 4 ------------ 4 5 ------------ 5 6 ------------ 6 7 ------------ 7 8 ------------ 8 20 ------------ 20 Note that this cable also supports RTS/CTS flow control signals ( pins 4 and 5 ) 4) Flow control. Wherever possible, RTS/CTS flow control should be used when connecting to a modem. However, not all MIPS serial ports support RTS/CTS. Refer to the RISCos 4.50 Release Notes sections 2.7.6 and 2.7.8 for a description of what machines / ports support what signals on what pins. NOTE: If using uucp file transfer, the modem should be set up to NOT use XON/XOFF flow control. Generation of Xon or Xoff flow control characters by the modems will break the uucp file transfer protocol. RTS/CTS or no flow control should be used; the uucp protocol will handle re-transmission of lost characters. 5) The next thing is to set up the gettydef entry for use by uugetty. The following entry sets up RTS/CTS flow control and sets HUPCL. HUPCL makes sure that when cu or uugetty exits, and this is the last close of the serial line, the DTR signal from the MIPS box is dropped so that the modem correctly disconnects from the phone line and does not accept any more incoming calls. When cu or uugetty re-opens the serial line, DTR will be re-asserted. MDMBUF should NOT be set, as we are using DTR/DCD fo modem control and NOT hardware handshaking. Example /etc/gettydefs entry: modem_19200# B19200 HUPCL #B19200 SANE HUPCL RTSCTS TAB3 #\r\n\n$HOSTNAME login: #modem_9600 Example /etc/inittab entry for starting uugetty : t1:234:respawn:/usr/lib/uucp/uugetty -r -t 30 ttym1 modem_19200 none LDISC0 6) Modem settings. Below is an example set up for a Telebit T2500 modem that can be used as a reference to set up other modems. E0 F1 M1 Q0 T V1 W0 X3 Y0 &P0 &T4 Version GF7.00-T2500SA S00:002 S01=000 S02=043 S03=013 S04=010 S05=008 S06=002 S07:060 S08=002 S09=006 S10=007 S11=070 S12=050 S18=000 S25=005 S26=000 S38=000 S41:001 S45=000 S47=004 S48=000 S49=000 S50:254 S51:254 S52:002 S54:003 S55=000 S56=017 S57=019 S58:002 S59=000 S61=150 S62=003 S63=001 S64=000 S65=000 S66:001 S67=000 S68:002 S69=000 S90=000 S91=000 S92:001 S93=008 S94=001 S95:002 S96=001 S97=000 S98=003 S100=000 S101=000 S102=000 S104=000 S105=001 S106=000 S107=020 S110=255 S111:030 S112=001 S121=000 S130:003 S131:001 S150=000 S151=004 S152=001 S153=001 S154=000 S155=000 S157=000 S158=000 S160=010 S161=020 S162=002 S163=003 S164=007 S169=000 S255=000 N0:1 Some of the more important registers : S0 set to 2 tells the modem to answer incoming calls after 2 rings. S50 set to 254 tells the modem to attempt to connect to the remote modem at a speed equal to the speed that the last AT command was received on the interface. S51 set to 254 sets the default modem interface speed to Automatic select, with a default of 19200 ( to match the speed of our uugetty ). S52 set to 2 tells the modem to perform a hard reset and enter command mode when an on to off transition of DTR occurs. Also tells the modem to only answer incoming calls if DTR is true. S58 set to 2 tells the modem that we ( the machine ) will use full duplex RTS/CTS flow control. The modem will not send data when RTS is turned off. S66 set to 1 tells the modem to lock the interface speed and to use flow control as specified by S58 and S68. S67 set to 0 tells the modem to use CTS to control data flow by the method specified in S68. S68 set to 2 tells the modem to use full duplex RTS/CTS flow control. The modem will turn CTS off when it wants to stop flow from the machine. S131 set to 1 tells the modem to only set DCD on when carrier is detected from the remote modem ( that is, a connection has been established ). E0 and F1 switch the modem echo off. If this is on, then the uugetty may loop. ( uugetty outputs the login prompt, the modem echos this back, uugetty thinks somebody is trying to log in, outputs the password prompt. The modem echoes this back; uugetty says invalid login, outputs the login prompt etc. etc. ) 6) Some example uucp Dialers entries for use with the modem settings shown above. tb1200 =W-, "" A\pA\pA\pT OK ATS50=2DT\T CONNECT\s1200 tb2400 =W-, "" A\pA\pA\pT OK ATS50=3DT\T CONNECT\s2400 tb9600 =W-, "" A\pA\pA\pT OK ATS50=6DT\T CONNECT\s9600 tbfast =W-, "" A\pA\pA\pT OK ATS50=255DT\T CONNECT\sFAST tbauto =W-, "" A\pA\pA\pT OK ATS50=0DT\T CONNECT\s Note that these all set the S50 register accordingly. This register controls how the modem chooses the speed to connect to the remote modem. S50 = 0 - Automatic speed determination S50 = 2 - 1200 bps S50 = 3 - 2400 bps S50 = 6 - 9600 bps S50 = 255 - FAST operation ( 19200 bps) 7) Some example uucp Devices entries for use with the above modem settings and Dialers entries. ACU ttym1 - 1200 tb1200 ACU ttym1 - 2400 tb2400 ACU ttym1 - 9600 tb9600 ACU ttym1 - 19200 tbfast AACU ttym1 - 19200 tbauto 8) Some example uucp Systems entries for use with the above modems settings and Devices and Dialers entries. Machine1 Any ACU 1200 1234561234 "" \r login:-\r\r-login: fred word: bloggs Machine2 Any ACU 2400 1234561235 "" \r login:-\r\r-login: fred word: bloggs Machine3 Any ACU 9600 1234561236 "" \r login:-\r\r-login: fred word: bloggs Machine4 Any ACU 19200 1234561237 "" \r login:-\r\r-login: fred word: bloggs Machine5 Any AACU 19200 1234561238 "" \r login:-\r\r-login: fred word: bloggs Summary ------- It is not easy to describe the exact steps to take for every type of modem connected to every type of MIPS serial port. The important thing is to understand the basic concepts. These are : The serial line being used must be using modem control. That is, CLOCAL is OFF. The easiest way to do this is to use a device name with a minor number greater than 128. For example, the device name /dev/tty1 refers to the second serial port on the RC3240. It has a minor number of 1, which means that the default is to not use modem control. /dev/ttym1 refers to the exact same port, and has the same major number. However, its minor number is that of tty1 + 128 = 129. This means that modem control is the default, i.e CLOCAL is OFF. This is the device to use. Modem control MUST be used because there must be some mechanism to tell uugetty that a connection to a remote modem has been made, and so it should wake up. Without this, uugetty will always create a lockfile in /usr/spool/locks and hence cu will not be able to make outgoing calls, as it will see that the line is already locked. uugetty normally opens the serial line with the O_NDELAY flag clear. This means that when it opens a serial line with modem control enabled, it will go to sleep until DCD is turned on. The modem and cable should be set up so that DCD is switched on only when a connection to another modem has been made. DCD going on wakes up uugetty. It looks in /usr/spool/locks for a lockfile associated with the serial line. If one exists, this means some other program ( e.g., cu ) is using the line, and so uugetty goes back to sleep waiting for the lock file to go away. If no lockfile exists, then uugetty creates one, and then outputs the login prompt. cu is normally able to make outgoing calls because it opens the serial line with O_NDELAY set; that is, it does not have to wait for DCD to come on. The other important thing to remember is that the serial line must have HUPCL set. This ensures that when no process has the serial line open, DTR out of the MIPS box is off. When uugetty and/or cu has the line open, DTR is on. This ensures that the modem is able to answer incoming calls and also that the modem correctly disconnects the phone line at the end of a call out. And finally; DO NOT USE XON/XOFF flow control if using uucp to transfer files ( uucico ). Use RTS/CTS flow control if the specific MIPS port and the modem support it; otherwise, use no flow control. The uucp file transfer protocol will handle re-transmission of lost data. ( Note. The cu 'get' and 'put' commands do not use the uucp file transfer protocol ). One final note. kermit shipped with RISCos 4.5x does not conform to the cu/uugetty/uucico locking protocol. kermit creates its lockfile in /usr/spool/uucp; uugetty etc. create their lockfiles in /usr/spool/locks. Also, kermit opens the serial line with O_NDELAY clear, and so will block waiting for DCD. Therefore, kermit cannot share a line with cu/uugetty/uucico. END.. --trevc-- Trevor Cotton, Sustaining Engineering, MIPS Computer Systems Inc. MS 6-05, 930 DeGuigne Drive, Sunnyvale, CA 94088-3650 Tel: +1 408 524 7286 Fax: +1 408 524 7521 Email: {wyse,ames,decwrl,pyramid}!mips!trevc trevc@mips.com