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GUtil
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uuserdump.c
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C/C++ Source or Header
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1990-01-10
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4KB
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151 lines
/*
* UUSERDUMP.C
*
* (C) Copyright 1989-1990 by Matthew Dillon, All Rights Reserved.
*
* UUSERDUMP filename
*
* KEY THINGS ABOUT UUSER: USED AS STDIN/STDOUT
*
* Currently UUSER: works only with single sessions started
* by Getty (this has to do with how UUSER: deals with carrier
* detect). THIS WILL BE FIXED.
*
* (1) Use Level 1 I/O if you can (read/write)
* read() returns 0 on timeout, -1 on carrier lost
* otherwise, read() returns the immediate number of
* data bytes ready up to the amount you requested.
* (i.e. if you read(0,buf,256) you can get anywhere from
* -1, 0, 1 to 256 back).
*
* write() returns the number you wrote or -1 (lost carrier)
*
* To 'poll' data ready you can read(0, NULL, 0) .. reading
* 0 bytes returns 0 (data ready) or -1 (data not ready).
* NOTE: 0 (data ready) will be returned if carrier is lost
* when you read 0 bytes... this is so your program thinks
* data is ready and when it does a real read it finds that
* carrier was lost!
*
* (2) If you want to use Level 2 I/O (stdio) I suggest you use
* it for writing only. If you really want to use it for
* reading remember that the timeout will cause an EOF
* condition which must be cleared (clrerr()). And you
* must call ferror() to determine whether an EOF is an
* EOF (timeout()) or an actual error (lost carrier).
*/
#include <proto/all.h>
#include <stdio.h>
#include "/version.h"
IDENT(".00");
void
CXBRK() /* on BREAK */
{
exit(1);
}
char buf[256];
short i;
void
main(ac, av)
char *av[];
{
short i;
char c;
short n;
FILE *fi = fopen(av[1], "r");
/*
* set output to line buffering (stdio), else it will use
* file buffering! Which is bad if we want to catch ^S/^C
*/
setvbuf(stdout, NULL, _IOLBF, 0);
if (ac == 1)
exit(1);
if (fi == NULL)
printf("Info file %s not available\r\n", av[1]);
printf("Dumping info file (suggest capture), hit Enter when ready\n");
fflush(stdout);
/*
* Getty uses the R1000 option, so there is a one second timeout
* on reads when no data is present. If data is present, UUSER:
* returns the number of bytes immediately available regardless of
* how many you requested.
*/
for (i = 0; i < 60; ++i) {
n = read(0, &c, 1);
if (n < 0) /* lost carrier */
exit(1);
/* success */
if (n > 0 && (c == 10 || c == 13))
goto skip;
/* timeout */
}
exit(1);
skip:
while (fgets(buf, 256, fi)) {
if (CheckControl())
break;
fputs(buf, stdout);
}
fclose(fi);
printf("End of dump, any key to disconnect\n");
fflush(stdout);
for (i = 0; i < 60; ++i) {
n = read(0, &c, 1);
if (n == 0) /* 1 second timeout */
continue;
break; /* any key or lost cd */
}
}
/*
* Here we use a UUSER: trick ... requesting 0 bytes in a read()
* incurs NO timeout. 0 is returned if data is ready, -1 if data
* is not ready.
*
* Another way to do it is to dump a seconds worth of data, then
* call read() (which blocks for up to 1 second if no data is
* ready, but the user doesn't see that because we've already queued
* a second's worth of data). The first method is better because
* there is finer granularity (that is, the one used below)
*/
CheckControl()
{
char c = 0;
short n;
if (read(0, NULL, 0) == 0) { /* returns 0=data ready, -1=not rdy */
read(0, &c, 1);
if (c == ('s'&0x1F)) { /* ^S */
for (;;) {
n = read(0, &c, 1);
if (n < 0) /* lost carrier */
exit(1);
if (n == 0) /* timeout */
continue;
break; /* got a key */
}
return(0);
}
if (c == ('c'&0x1F)) /* ^C */
return(1);
}
return(0);
}