From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <a14e85571895b8ff58bc08d27aa878ae@plan9.bell-labs.com>
From: "Russ Cox" <rsc@plan9.bell-labs.com>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] fs error msg: didn't like (1460 274) byte message
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Date: Wed, 25 Sep 2002 14:24:23 -0400
Topicbox-Message-UUID: f4c5974e-eaca-11e9-9e20-41e7f4b1d025

The problem is the buffer can be arbitrarily sized, though
typically 8192+IOHDRSZ is the max a client and server will
agree on.  Cpu uses a much larger max size to improve graphics
performance.

Here's a fixed xfer9p.  I forgot that the initial count
includes itself.

void
xfer9p(int from, int to)
{
	char *buf;
	uint nbuf;
	int n;

	nbuf = 256;
	buf = malloc(nbuf);
	if(buf == nil)
		sysfatal("xfer: malloc %ud: %r", nbuf);

	for(;;){
		if(readn(from, buf, 4) != 4)
			break;
		n = GBIT32(buf);
		if(n > nbuf){
			nbuf = n+8192;	/* 8192: slop */
			buf = realloc(buf, nbuf);
			if(buf == nil)
				sysfatal("xfer: realloc %ud: %r", nbuf);
		}
		if(readn(from, buf+4, n-4) != n-4)
			break;
		if(write(to, buf, n) != n)
			break;
	}
}

Russ