larss@nada.kth.se (Lars Schylberg) (06/08/89)
A problem for unix programmers.
I have a problem how to create fifo files on the Apollo
system. We are currently running BSD4.2 and 9.7.1.
We are trying to port a public domain software called GRASS
(Geographic Resoures Analysis Support System) to Apollo, which prior
have been running on SUN and MASSCOMP. The interprocess communication
in this package between the program and the Xwindow graphic driver is
handled with fifo files. We have a monitorcap file that defines how
the fifo files should connect. eg:
APOLLO:driver/APOLLO:Apollo X graphics display:/dev/fifo.a /dev/fifo.b::any terminal
To get this to work we are supposed to create two devices with the
command:
mknod -p /dev/fifo.a
mknod -p /dev/fifo.b
This command is however not availble in 9.7. I looked in the standard
library and found the mknod(2). I wrote this program:
main()
{
int mode;
mode = 0010000;
mknod("/dev/fifo.a",mode);
mknod("/dev/fifo.b",mode);
}
and after that chmod 7777 fifo.a and fifo.b to be able to open those
from our program. That didn't work however. What have I done wrong.
I not too experienced in interporcess programming so I don't want to
rewrite this with sockets which I tried once before. I would be very
glad for advice and hints how to get around this.
When we chance to OS 10.1, (we just have it on 1 out 8 nodes now)
I've seen there is a command mknod(8) with the syntax:
/etc/mknod name [b] / [c] major minor
I suppose that I want to create a character device with c
but what do I set major and minor to. The system source file
conf.c is something I can't find. Nither can the Stockholm
Apollo office support group. HELP !!!!.
Lars Schylberg Email: larss@fmi.kth.se
Department of Photogrammetry (Internet)
Royal Institute of Technolgy
S-100 44 STOCKHOLM Tel. +46 8 790 86 33 (office)
SWEDEN Fax. +46 8 10 91 99
/*----------------------------------------------------------------*/GBOPOLY1@NUSVM.BITNET (fclim) (06/12/89)
Hi, In article <1176@draken.nada.kth.se> larss%draken%kth%mcvax.uucp@uunet.uu. net (Lars Schylberg) writes >I have a problem how to create fifo files on the Apollo >system. We are currently running BSD4.2 and 9.7.1. > >To get this to work we are supposed to create two devices with the >command: > >mknod -p /dev/fifo.a >mknod -p /dev/fifo.b > >This command is however not availble in 9.7. I looked in the standard FIFOs are System V goodies and not BSD-ism. Mknod(8) is available under SR9.7 -- look for it in /sys5/etc where /sys5 is the root for all SysV stuff. The command is mknod /dev/fifo.a p -- the file (/dev/fifo.a) created will be a FIFO because of the p option. >This command is however not availble in 9.7. I looked in the standard >library and found the mknod(2). I wrote this program: > >main() >{ > int mode; > mode = 0010000; > mknod("/dev/fifo.a",mode); > mknod("/dev/fifo.b",mode); >} > >and after that chmod 7777 fifo.a and fifo.b to be able to open those >from our program. That didn't work however. What have I done wrong. I do not have my man pages with me; so I can't really tell you. In chmod 7777 /dev/fifo.a the most significant 7 is the sticky bit (setuid, etc) and does not make /dev/fifo.a a FIFO. The one in mode = 0010000 may be the password to make /dev/fifo.a a FIFO; you have to check the man pages (chmod(2) or is it stat(2)) on this -- look up the System V version rather than the BSD4.2 version. >I've seen there is a command mknod(8) with the syntax: > >/etc/mknod name [b] / [c] major minor > >I suppose that I want to create a character device with c >but what do I set major and minor to. The system source file See "The Design of the Unix operating system" (Prentice Hall ISBN-0-87692-516-6 ) by Maurice Bach (chapter on I/O) for an explaination of major/minor -- he explained it better than I ever could. Hope this has been of help. fclim --- gbopoly1 % nusvm.bitnet @ cunyvm.cuny.edu computer centre singapore polytechnic dover road singapore 0513.
weber_w@apollo.COM (Walt Weber) (06/14/89)
In article <1176@draken.nada.kth.se> larss@nada.kth.se (Lars Schylberg) writes: >A problem for unix programmers. > >I have a problem how to create fifo files on the Apollo >system. We are currently running BSD4.2 and 9.7.1. I believe that you will find that FIFO's were not supported under bsd4.2, and were added to bsd4.3. You would be able to create the fifo's using the Sys5 mknod which came with your Domain/IX (since you are running under sr9), or by compiling your program which calls mknod(2) under the sys5 systype. >When we chance to OS 10.1, (we just have it on 1 out 8 nodes now) >I've seen there is a command mknod(8) with the syntax: >/etc/mknod name [b] / [c] major minor > >I suppose that I want to create a character device with c >but what do I set major and minor to. >Lars Schylberg Email: larss@fmi.kth.se No, it is not a character special device. The released software does not appear to have a way to create the FIFO using bsd4.3 mknod(8). You should be able to write a short program (under bsd4.3) which would make the call to mknod(2) with the mode bit for S_IFIFO set (see sys/stat.h), or use the Sys5.3 version of mknod(8) (found listed as mknod(1m)). I have submitted apr #dd1ff in your name against this problem, and you will be receiving an official answer from us in writing. Sorry for the problem. ...walt... PS - Note that you can submit apr's via email (if you have internet access); type 'man mkapr' on an sr10 system. -- Walt Weber Apollo Computer (508) 256-6600 x8315 People's Republic of Massachusetts -The views expressed herein are personal, and not binding on ANYONE-