ITEM: CL1420L

Sending console output to multiple devices

ENV:
AIX 3.2.5
7012-360

DESC:
I want to take the console messages and send them to multiple 
devices (terminals, telnet session pts's, etc.)

ACT:
The console can only be one "file" such as /dev/tty0 or /tmp/junk.
There are a few things that you could do to get the console 
output going to several places:

1) swcons /tmp/consolefile
   Then go to any (and as many) sessions as you want and do:
      tail -f /tmp/consolefile 
           or
      tail -f /tmp/consolefile &

   This way console messages go to a file and also the screen of
   each session running the tail on that file.

2) Make the console a named pipe with swcons and run a daemon that
   reads from the named pipe and writes its output to whatever
   locations desired.  Attached below is a C program I wrote to do
   just that:

/*
                                                        IBM Corp.
                                                        3/6/96

                                tpiped

        The code below is provided as-is with no guarantee of any kind.
        The purpose of this program is to read from a named pipe and then
        send the data read from that named pipe to an arbitrary number of
        places.  Some example uses would be to send a print job to one
        queue and then have it print on several printers - ie get your jobs
        in triplicate.  You could also send a copy to the console, or to a
        tape drive for archival, etc.

        The first step is to create a named pipe, for example /dev/mypipe
                mknod /dev/mypipe p

        With tpiped running in the background, anything that is read from
        the named pipe is sent to the destinations.  For example:

        tpiped /dev/mypipe /dev/lp0 /dev/lp1 /dev/console /dev/rmt0.1 &

        Now anything that is sent to /dev/mypipe will be sent to  /dev/lp0,
        /dev/lp1, /dev/console, and /dev/rmt0.1
        To have the print queueing system send jobs to this pipe, just create
        a queue that prints to the file /dev/mypipe.
*/   


\#include \

\#define        MAXDEST 16      /* Max number of places piped output can be sent */
\#define BUFSIZE 256    /* Max chunk read from the pipe in a single read */


int main(int argc, char **argv)
{       FILE *pipe;                     /* The named pipe we read from  */
        FILE *dest[MAXDEST + 2];        /* The destinations we write to */
        char buffer[BUFSIZE];           /* The buffer we read into      */
        int i;


        /* There must be at least 3 arguments - the command name, the name
           of the input pipe, and at least one destination.  Of course it
           is silly to use this program without at least 2 destinations.
        */
        if (argc \< 3) 
        {
           fprintf(stderr, "Usage: %s sourcepipe dest1 [dest2 ... destn]\\n", 
                argv[0]);
           exit(1);
        }


        /* Open the pipe for reading */
        pipe  = fopen(argv[1], "r");

        /* Open each destination for output */
        for(i = 2; i \< argc; i++)  
           dest[i] = fopen(argv[i], "a");


        /* Now infinitely read from the pipe and send to the destinations */
        while(1)
           if (fgets(buffer, sizeof(buffer), pipe) != NULL)
             for (i = 2; i \< argc; i++)
             {
               fputs(buffer, dest[i]);
               fflush(dest[i]);
             }
}   


NEXT:
Faxing above to you at 804-354-7839

Response:

Closing with Customer Approval



Support Line: Sending console output to multiple devices ITEM: CL1420L

Dated: January 1997 Category: N/A

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