pointed out by clang-analyzer

When a connection is no longer used, it is kept in the cache. If the
cache is full, the oldest idle connection is closed. If no connection is
idle, the current one is closed instead.

Provided additional clarification about the logic of the authenticate()
functions following commit 6b6bdc83 and b4270a9a.

Tidied up code from commit 6b6bdc83bdUpdated where a few instances of
the pop3c struct variable used the longer conndata struct rather than
matching what other code in pop3_authenticate() used.

Fixed an issue where (lib)curl is compiled without support for a
supported challenge-response based SASL authentication mechanism, such
as CRAM-MD5 or NTLM, the server doesn't support the LOGIN or PLAIN
mechanisms and (lib)curl doesn't fallback to Clear Text authentication.

Note: In order to fallback to Clear Text authentication properly this
fix adds support for the LOGINDISABLED server capability.
imap: Fixed no known authentication mechanism when fallback is required

Fixed an issue where (lib)curl is compiled without support for a
supported challenge-response based SASL authentication mechanism, such
as CRAM-MD5 or NTLM, the server doesn't support the LOGIN or PLAIN
mechanisms and (lib)curl doesn't fallback to Clear Text authentication.

Note: In order to fallback to Clear Text authentication properly this
fix adds support for the LOGINDISABLED server capability.

Related bug: http://curl.haxx.se/mail/lib-2013-02/0004.html
Reported by: Stanislav Ivochkin

Fixed an issue where (lib)curl is compiled without support for a
supported challenge-response based SASL authentication mechanism, such
as CRAM-MD5 or NTLM, the server doesn't support the LOGIN or PLAIN
mechanisms and (lib)curl doesn't fallback to APOP or Clear Text
authentication.

Bug: http://curl.haxx.se/mail/lib-2013-02/0004.html
Reported by: Stanislav Ivochkin

Remove timeout argument that's never used.

Make the actual connection get detected on a single spot to reduce code
duplication.

Store the IPv6 state already when the connection is attempted.

Curl_perfom is no longer used anywhere since the always-multi commit
c4312741, and some related functions were used only from within
Curl_perfom.

There was a bug where, if SSLWrite() returned errSSLWouldBlock but did
succeed in transmitting at least something, then we'd incorrectly
resend the packet. Now we never take errSSLWouldBlock as a sign that
nothing was transferred to/from the server.

Bug: http://curl.haxx.se/mail/lib-2013-01/0295.html
Reported by: Bruno de Carvalho

The state machine should only be changed to SMTP_STARTTLS when the
STARTTLS command has been successfully sent to the server.

The state machine should only be changed to POP3_STARTTLS when the
STLS command has been successfully sent to the server.

The state machine should only be changed to IMAP_STARTTLS when the
STARTTLS command has been successfully sent to the server.

Updated the ssldone comment as multi mode is always used internally now.

Minor code tidy up to add comments similar to those used in the pop3
and imap end of resp functions, in order to assist anyone reading the
code and highlight the similarities between each of these protocols.

The most recent version of the SMTP RFC is RFC5321 and not RFC2821 as
previously documented.

Added RFC1870 and re-ordered list numerically.

smtp_state_upgrade_tls() would attempt to incorrectly complete the
upgrade to smtps and start the EHLO command if
Curl_ssl_connect_nonblocking() returned a failure code and if ssldone
was set to TRUE. This would only happen when a non-blocking API hadn't
been provided by the SSL implementation and curlssl_connect() was
called underneath.

pop3_state_upgrade_tls() would attempt to incorrectly complete the
upgrade to pop3s and start the CAPA command if
Curl_ssl_connect_nonblocking() returned a failure code and if ssldone
was set to TRUE. This would only happen when a non-blocking API hadn't
been provided by the SSL implementation and curlssl_connect() was
called underneath.

imap_state_upgrade_tls() would attempt to incorrectly complete the
upgrade to imaps and start the CAPABILITY command if
Curl_ssl_connect_nonblocking() returned a failure code and if ssldone
was set to TRUE. This would only happen when a non-blocking API hadn't
been provided by the SSL implementation and curlssl_connect() was
called underneath.

Small tidy up to remove unnecessary return statements prior to the next
fix.

The most recent version of the RFC is RFC4422 and not RFC2222 as
previously documented.

The most recent version of the SASL RFC is RFC4422 and not RFC2222 as
previously documented.

- document the double-quote and backslash need be escaped if quoting.
- libcurl formdata escape double-quote in filename by backslash.
- curl formparse can parse filename both contains '"' and ',' or ';'.
- curl now can uploading file with ',' or ';' in filename.

Bug: http://curl.haxx.se/bug/view.cgi?id=1171

Extended the fix from commit 8b15c84e to additionally exclude
pop3_state_apop_resp() if the CURL_DISABLE_CRYPTO_AUTH flag is
defined.

Bug: http://curl.haxx.se/mail/archive-2013-01/0017.html
Reported by: Ulrich Doehner

Corrected some function argument definitions to maximize the 80
character line length limit and be in keeping with the curl
coding style.

Fixed an issue where Curl_ssl_connect_nonblocking() wouldn't complete
correctly and the ssldone flag wouldn't be set to true for pop3s based
connections.

Bug introduced in commit: 4ffb8a63.

Remove internal separated behavior of the easy vs multi intercace.
curl_easy_perform() is now using the multi interface itself.

Several minor multi interface quirks and bugs have been fixed in the
process.

Much help with debugging this has been provided by: Yang Tse

Fixes initial proxy response being processed by the tunneled protocol
handler instead of the HTTP wrapper handler. This issue would trigger
upon delayed CONNECT response from the proxy.

Additionally fixes a multi interface code-path in which connections
would not time out properly.

This does not fix known bug #39.

URL: http://curl.haxx.se/mail/lib-2013-01/0191.html

Do not use the error messages from NSS for errors not occurring in NSS.

It referred to it by the wrong name and said it returned the wrong value.

Reported by: Gisle Vanem

This commit fixes a regression introduced in 052a08ff.

NSS caches certs/keys returned by the SSL_GetClientAuthDataHook callback
and if we connect second time to the same server, the cached cert/key
pair is used.  If we use multiple client certificates for different
paths on the same server, we need to clear the session cache to force
NSS to call the hook again.  The commit 052a08ff prevented the session
cache from being cleared if a client certificate from file was used.

The condition is now fixed to cover both cases: consssl->client_nickname
is not NULL if a client certificate from the NSS database is used and
connssl->obj_clicert is not NULL if a client certificate from file is
used.

Review by: Kai Engert

This commit renames lib/setup.h to lib/curl_setup.h and
renames lib/setup_once.h to lib/curl_setup_once.h.

Removes the need and usage of a header inclusion guard foreign
to libcurl. [1]

Removes the need and presence of an alarming notice we carried
in old setup_once.h [2]

----------------------------------------

1 - lib/setup_once.h used __SETUP_ONCE_H macro as header inclusion guard
    up to commit ec691ca3 which changed this to HEADER_CURL_SETUP_ONCE_H,
    this single inclusion guard is enough to ensure that inclusion of
    lib/setup_once.h done from lib/setup.h is only done once.

    Additionally lib/setup.h has always used __SETUP_ONCE_H macro to
    protect inclusion of setup_once.h even after commit ec691ca3, this
    was to avoid a circular header inclusion triggered when building a
    c-ares enabled version with c-ares sources available which also has
    a setup_once.h header. Commit ec691ca3 exposes the real nature of
    __SETUP_ONCE_H usage in lib/setup.h, it is a header inclusion guard
    foreign to libcurl belonging to c-ares's setup_once.h

    The renaming this commit does, fixes the circular header inclusion,
    and as such removes the need and usage of a header inclusion guard
    foreign to libcurl. Macro __SETUP_ONCE_H no longer used in libcurl.

2 - Due to the circular interdependency of old lib/setup_once.h and the
    c-ares setup_once.h header, old file lib/setup_once.h has carried
    back from 2006 up to now days an alarming and prominent notice about
    the need of keeping libcurl's and c-ares's setup_once.h in sync.

    Given that this commit fixes the circular interdependency, the need
    and presence of mentioned notice is removed.

    All mentioned interdependencies come back from now old days when
    the c-ares project lived inside a curl subdirectory. This commit
    removes last traces of such fact.

Added support for asynchronous SSL upgrade when using the
multi-interface.