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Path: utzoo!watmath!clyde!burl!ulysses!mhuxl!houxm!ihnp4!mit-eddie!mp
From: mp@mit-eddie.UUCP (Mark Plotnick)
Newsgroups: net.news
Subject: Re: Wanted: news batching with compression
Message-ID: <1474@mit-eddie.UUCP>
Date: Fri, 23-Mar-84 16:47:36 EST
Article-I.D.: mit-eddi.1474
Posted: Fri Mar 23 16:47:36 1984
Date-Received: Sun, 25-Mar-84 08:55:13 EST
References: <149@forcm5.UUCP> <952@qubix.UUCP>
Organization: MIT, Cambridge, MA
Lines: 161

Here's a way to get news compression done.  Don't expect it
to be elegant, it only took half an hour.

There are two new filters, pnews to compact the news and unews
to uncompact it.  First, the compacting:

pnews for Berkeley systems:
#!/bin/sh
# pnews for berkeley systems
PATH=$PATH:/usr/local/lib/news
export PATH
TMP=/tmp/pn$$
rm -f $TMP >/dev/null 2>&1
compact > $TMP 2>/dev/null
echo "#! unews "`filesize $TMP`
cat $TMP
rm -f $TMP >/dev/null 2>&1

For USG systems, this may work (I don't have access to a USG system
that runs netnews, so this is untested)

# pnews for USG
PATH=$PATH:/usr/local/lib/news
export PATH
TMP=/tmp/pn$$
rm -f $TMP $TMP.z >/dev/null 2>&1
cat <&0 >$TMP
pack -f $TMP >/dev/null 2>&1
echo "#! unews "`filesize $TMP.z`
cat $TMP.z
rm -f $TMP $TMP.z >/dev/null 2>&1

The command line in your hourly file should look something like:
batch /usr/spool/news/batch/whuxle | pnews | uux - -n -r whuxle\!rnews

Oh yes, you need filesize.c:
#include <sys/types.h>
#include <sys/stat.h>

main(argc, argv)
char **argv;
{
	struct stat sbuf;

	if (stat(argv[1], &sbuf) == -1)
		printf("0\n");
	else
		printf("%ld\n", sbuf.st_size);
}

OK, now on the receiving end, you need a slightly more
flexible unbatch.c:

/*
 * unbatchnews: extract news in batched format and process it one article
 * at a time.  The format looks like
 *	#! rnews 1234
 *	article containing 1234 characters
 *	#! rnews 4321
 *	article containing 4321 characters
 */

# include <stdio.h>
# include "defs.h"	/* to get RNEWS definition */
static char *sccsid = "@(#)unbatch.c	1.3	4/23/83";

char buf[512];
char *command;
#define UNEWS "/usr/local/lib/news/unews"

main(ac, av)
char **av;
{
	register int c;
	register FILE *pfn;
	register long size;
	char *filename;
	int pid, wpid, exstat;
	char *mktemp();
	long atol();

	/* first, close any extraneous files that uucp may have left open */
	for(c=3; c<20;c++) close(c);
	filename = mktemp("/tmp/unbnewsXXXXXX");
	while(fgets(buf, sizeof buf, stdin) != NULL) {
		while (strncmp(buf, "#! rnews ", 9) && strncmp(buf, "#! unews ", 9)) {
			fprintf(stderr, "out of sync, skipping %s\n", buf);
			if (fgets(buf, sizeof buf, stdin) == NULL)
				exit(0);
		}
		command = (strncmp(buf, "#! unews ", 9)==0) ? UNEWS : RNEWS;
		if (buf[strlen(buf)-1]=='\n')
			buf[strlen(buf)-1]='\0';	/* no use aggravating atol */
		size = atol(buf+9);
		if(size <= 0)
			break;
		pfn = fopen(filename, "w");
		while(--size >= 0 && (c = getc(stdin)) != EOF)
			putc(c, pfn);
		fclose(pfn);

		/*
		 * If we got a truncated batch, don't process the
		 * last article; it will probably be received again.
		 */
		if (size > 0)
			break;

		/*
		 * rnews < filename
		 */
		while ((pid = fork()) == -1) {
			fprintf(stderr, "fork failed, waiting...\r\n");
			sleep(60);
		}
		if (pid == 0) {
			close(0);
			open(filename, 0);
			execlp(command, command, 0);
			perror(command);
			exit(1);
		}
		while ((wpid = wait(&exstat)) >= 0 && wpid != pid)
			;
	}
	unlink(filename);
}

This new unbatch allows both "rnews" and "unews" markers.
I thought of just allowing arbitrary shell commands after the
"#!", but this would open up too many security holes.

unews on ucb looks like:

#!/bin/sh
# unews for berkeley systems
PATH=$PATH:/usr/local/lib/news
export PATH
uncompact| rnews


On USG, one possibility for unews is:

# unews for USG
PATH=$PATH:/usr/local/lib/news
export PATH
ZTMP=/tmp/un$$.z
rm -f $ZTMP
cat <&0 >$ZTMP
pcat $ZTMP | rnews
rm -f $ZTMP

But note that since this isn't a kernelly-executable file, you'd
probably have to replace the execlp in unbatch.c with a call
to system() or "sh -c".

	Mark Plotnick

P.S. If you exchange news with 2 or more systems, a MUCH better way
of reducing your uucp time would be to implement an ihave/sendme
protocol.