From 2010baa9c1222ce144a45f1d7485b958e9be88fd Mon Sep 17 00:00:00 2001
From: des <des@FreeBSD.org>
Date: Tue, 28 Jan 2014 12:48:17 +0000
Subject: Solve http buffering issues and hangs once and for all (hopefully!)
 by simply not trying to return exactly what the caller asked for - just
 return whatever we got and let the caller be the judge of whether it was
 enough.  If an error occurs or the connection times out after we already
 received some data, return a short read, under the assumption that the next
 call will fail or time out before we read anything.

As it turns out, none of the code that calls fetch_read() assumes an
all-or-nothing result anyway, except for a couple of lines where we
read the CR LF at the end of a hunk in HTTP hunked encoding, so the
changes outside of fetch_read() and http_readfn() are minimal.

While there, replace select(2) with poll(2).

MFC after:	3 days
---
 lib/libfetch/http.c | 38 +++++++++++++++++---------------------
 1 file changed, 17 insertions(+), 21 deletions(-)

(limited to 'lib/libfetch/http.c')

diff --git a/lib/libfetch/http.c b/lib/libfetch/http.c
index 87535f0..fc43a97 100644
--- a/lib/libfetch/http.c
+++ b/lib/libfetch/http.c
@@ -208,6 +208,7 @@ static int
 http_fillbuf(struct httpio *io, size_t len)
 {
 	ssize_t nbytes;
+	char ch;
 
 	if (io->error)
 		return (-1);
@@ -249,10 +250,8 @@ http_fillbuf(struct httpio *io, size_t len)
 	io->chunksize -= io->buflen;
 
 	if (io->chunksize == 0) {
-		char endl[2];
-
-		if (fetch_read(io->conn, endl, 2) != 2 ||
-		    endl[0] != '\r' || endl[1] != '\n')
+		if (fetch_read(io->conn, &ch, 1) != 1 || ch != '\r' ||
+		    fetch_read(io->conn, &ch, 1) != 1 || ch != '\n')
 			return (-1);
 	}
 
@@ -268,31 +267,28 @@ static int
 http_readfn(void *v, char *buf, int len)
 {
 	struct httpio *io = (struct httpio *)v;
-	int l, pos;
+	int rlen;
 
 	if (io->error)
 		return (-1);
 	if (io->eof)
 		return (0);
 
-	for (pos = 0; len > 0; pos += l, len -= l) {
-		/* empty buffer */
-		if (!io->buf || io->bufpos == io->buflen)
-			if (http_fillbuf(io, len) < 1)
-				break;
-		l = io->buflen - io->bufpos;
-		if (len < l)
-			l = len;
-		memcpy(buf + pos, io->buf + io->bufpos, l);
-		io->bufpos += l;
+	/* empty buffer */
+	if (!io->buf || io->bufpos == io->buflen) {
+		if (http_fillbuf(io, len) < 1) {
+			if (io->error == EINTR)
+				io->error = 0;
+			return (-1);
+		}
 	}
 
-	if (!pos && io->error) {
-		if (io->error == EINTR)
-			io->error = 0;
-		return (-1);
-	}
-	return (pos);
+	rlen = io->buflen - io->bufpos;
+	if (len < rlen)
+		rlen = len;
+	memcpy(buf, io->buf + io->bufpos, rlen);
+	io->bufpos += rlen;
+	return (rlen);
 }
 
 /*
-- 
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