GopherProxy

	Fix handling of unexpected hangups - quark - quark web server
	git clone git://git.suckless.org/quark
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	---
	commit f1892c4dffa7df6995cd8c9ebd47e0ce7f0e457e
	parent 3729e7222aafc4c4ca30351748a89e05f78e2230
	Author: Laslo Hunhold <[email protected]>
	Date: Sun, 31 Jan 2021 00:39:11 +0100

	Fix handling of unexpected hangups

	During slowloris-stress-testing I noticed that closing the tool would
	pretty reliably trigger a case where quark was continuously getting
	edge-triggered on EPOLLIN and notified that there was something to read
	on the now definitely closed client-sockets.

	This was wrong and due to the fact that I mishandled the case when
	read() returns 0 in http_recv_header(). The condition read()==0 and
	EPOLL or EWOULDBLOCK does not indicate that you should try again. It's
	an EOF-condition and should be handled as such.

	Given the request is incomplete at this point, this is handled as a
	bad request (HTTP status 400) mostly for the logs at this point, as
	being able to transmit the error page itself is highly unlikely.

	Signed-off-by: Laslo Hunhold <[email protected]>

	Diffstat:
	M http.c \| 10 +++++++++-

	1 file changed, 9 insertions(+), 1 deletion(-)
	---
	diff --git a/http.c b/http.c
	@@ -154,7 +154,7 @@ http_recv_header(int fd, struct buffer buf, int done)

	while (1) {
	if ((r = read(fd, buf->data + buf->len,
	- sizeof(buf->data) - buf->len)) <= 0) {
	+ sizeof(buf->data) - buf->len)) < 0) {
	if (errno == EAGAIN \|\| errno == EWOULDBLOCK) {
	/*
	* socket is drained, return normally,
	@@ -166,6 +166,14 @@ http_recv_header(int fd, struct buffer buf, int done)
	s = S_REQUEST_TIMEOUT;
	goto err;
	}
	+ } else if (r == 0) {
	+ /*
	+ * unexpected EOF because the client probably
	+ * hung up. This is technically a bad request,
	+ * because it's incomplete
	+ */
	+ s = S_BAD_REQUEST;
	+ goto err;
	}
	buf->len += r;