As rightfully complained by MSVC, do_write variable was used uninitialized.
Correct fix is to set it's initial value based on event happened.

This allows to proxy WebSockets by using configuration like this:

    location /chat/ {
        proxy_pass http://backend;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
    }

Connection upgrade is allowed as long as it was requested by a client
via the Upgrade request header.

Prodded by John Leach.

Note: use of {SHA} passwords is discouraged as {SHA} password scheme is
vulnerable to attacks using rainbow tables.  Use of {SSHA}, $apr1$ or
crypt() algorithms as supported by OS is recommended instead.

The {SHA} password scheme support is added to avoid the need of changing
the scheme recorded in password files from {SHA} to {SSHA} because such
a change hides security problem with {SHA} passwords.

Patch by Louis Opter, with minor changes.

If fastcgi end request record was split between several network packets,
with fastcgi_keep_conn it was possible that connection was saved in incorrect
state (e.g. with padding bytes not yet read).

Checks for f->padding before state transitions make code hard to follow,
remove them and make sure we always do another loop iteration after
f->state is set to ngx_http_fastcgi_st_padding.

With fastcgi_keep_conn it was possible that connection was closed after
FCGI_STDERR record with zero padding and without any further data read yet.
This happended as f->state was set to ngx_http_fastcgi_st_padding and then
"break" happened, resulting in p->length being set to f->padding, i.e. 0
(which in turn resulted in connection close).

Fix is to make sure we continue the loop after f->state is set.

After introduction of chunked request body reading support in 1.3.9 (r4931),
the rb->bufs wasn't set if request body was fully preread while calling the
ngx_http_read_client_request_body() function.

Reported by Yichun Zhang (agentzh).