Howard Chu brought the bulk work of this patch that properly
moves out the sending and recving of data to the parts of the
code that are properly responsible for the various ways of doing
so.
Daniel Stenberg assisted with polishing a few bits and fixed some
minor flaws in the original patch.
Another upside of this patch is that we now abuse CURLcodes less
with the "magic" -1 return codes and instead use CURLE_AGAIN more
consistently.
This is Hoi-Ho Chan's patch with some minor fixes by me. There
are some potential issues in this, but none worse than we can
sort out on the list and over time.
The main change is to allow input from user-specified methods,
when they are specified with CURLOPT_READFUNCTION.
All calls to fflush(stdout) in telnet.c were removed, which makes
using 'curl telnet://foo.com' painful since prompts and other data
are not always returned to the user promptly. Use
'curl --no-buffer telnet://foo.com' instead. In general,
the user should have their CURLOPT_WRITEFUNCTION do a fflush
for interactive use.
Also fix assumption that reading from stdin never returns < 0.
Old code could crash in that case.
Call progress functions in telnet main loop.
Signed-off-by: Ben Greear <greearb@candelatech.com>
from hostip.h to setup.h in order to allow proper inclusion in any file.
This represents no functional change at all in which resolver is used,
everything still works as usual, internally and externally there is no
difference in behavior.
command is a special "hack" used by the drftpd server, but even though it is
a custom extension I've deemed it fine to add to libcurl since this server
seems to survive and people keep using it and want libcurl to support
it. The new libcurl option is named CURLOPT_FTP_USE_PRET, and it is also
usable from the curl tool with --ftp-pret. Using this option on a server
that doesn't support this command will make libcurl fail.
rework patch that now integrates TFTP properly into libcurl so that it can
be used non-blocking with the multi interface and more. BLKSIZE also works.
The --tftp-blksize option was added to allow setting the TFTP BLKSIZE from
the command line.
transfer.c for blocking. It is currently used only by SCP and SFTP protocols.
This enhancement resolves an issue with 100% CPU usage during SFTP upload,
reported by Vourhey.
Fix SIGSEGV on free'd easy_conn when pipe unexpectedly breaks
Fix data corruption issue with re-connected transfers
Fix use after free if we're completed but easy_conn not NULL
in NSS-powered libcurl. Now the client certificates can be selected
automatically by a NSS built-in hook. Additionally pre-login to all PKCS11
slots is no more performed. It used to cause problems with HW tokens.
- Fixed reference counting for NSS client certificates. Now the PEM reader
module should be always properly unloaded on Curl_nss_cleanup(). If the unload
fails though, libcurl will try to reuse the already loaded instance.
KEEP_RECV to better match the general terminology: receive and send is what we
do from the (remote) servers. We read and write from and to the local fs.
out to be leaking cacerts. Kamil Dudka helped me complete the fix. The issue
is found in Redhat's bug tracker:
https://bugzilla.redhat.com/show_bug.cgi?id=453612
There are still memory leaks present, but they seem to have other reasons.
(http://curl.haxx.se/docs/adv_20090303.html also known as CVE-2009-0037) in
which previous libcurl versions (by design) can be tricked to access an
arbitrary local/different file instead of a remote one when
CURLOPT_FOLLOWLOCATION is enabled. This flaw is now fixed in this release
together this the addition of two new setopt options for controlling this
new behavior:
o CURLOPT_REDIR_PROTOCOLS controls what protocols libcurl is allowed to
follow to when CURLOPT_FOLLOWLOCATION is enabled. By default, this option
excludes the FILE and SCP protocols and thus you nee to explicitly allow
them in your app if you really want that behavior.
o CURLOPT_PROTOCOLS controls what protocol(s) libcurl is allowed to fetch
using the primary URL option. This is useful if you want to allow a user or
other outsiders control what URL to pass to libcurl and yet not allow all
protocols libcurl may have been built to support.
FTP with the multi interface: when a transfer fails, like when aborted by a
write callback, the control connection was wrongly closed and thus not
re-used properly.
This change is also an attempt to cleanup the code somewhat in this area, as
now the FTP code attempts to keep (better) track on pending responses
necessary to get read in ftp_done().
plain FTP connections, and it will then allow MKD to fail once and retry the
CWD afterwards. This is especially useful if you're doing many simultanoes
connections against the same server and they all have this option enabled,
as then CWD may first fail but then another connection does MKD before this
connection and thus MKD fails but trying CWD works! The numbers can
(should?) now be set with the convenience enums now called
CURLFTP_CREATE_DIR and CURLFTP_CREATE_DIR_RETRY.
Tests has proven that if you're making an application that uploads a set of
files to an ftp server, you will get a noticable gain in speed if you're
using multiple connections and this option will be then be very useful.
the condition in the previous request was unmet. This is typically a time
condition set with CURLOPT_TIMECONDITION and was previously not possible to
reliably figure out. From bug report #2565128
(http://curl.haxx.se/bug/view.cgi?id=2565128)
Curl_sspi_global_init() and Curl_sspi_global_cleanup() which previously were
named Curl_ntlm_global_init() and Curl_ntlm_global_cleanup() in http_ntlm.c
Also adjusted socks_sspi.c to remove the link-time dependency on the Windows
SSPI library using it now in the same way as it was done in http_ntlm.c.
CURLOPT_SOCKS5_GSSAPI_SERVICE and CURLOPT_SOCKS5_GSSAPI_NEC to allow libcurl
to do GSS-style authentication with SOCKS5 proxies. The curl tool got the
options called --socks5-gssapi-service and --socks5-gssapi-nec to enable
these.
They basically offer the same thing the NO_PROXY environment variable only
offered previously: list a set of host names that shall not use the proxy
even if one is specified.
now has an improved ability to do right when the multi interface (both
"regular" and multi_socket) is used for SCP and SFTP transfers. This should
result in (much) less busy-loop situations and thus less CPU usage with no
speed loss.
there are servers "out there" that relies on the client doing this broken
Digest authentication. Apache even comes with an option to work with such
broken clients.
The difference is only for URLs that contain a query-part (a '?'-letter and
text to the right of it).
libcurl now supports this quirk, and you enable it by setting the
CURLAUTH_DIGEST_IE bit in the bitmask you pass to the CURLOPT_HTTPAUTH or
CURLOPT_PROXYAUTH options. They are thus individually controlled to server
and proxy.
(http://curl.haxx.se/bug/view.cgi?id=2221237) that identified an infinite
loop during GSS authentication given some specific conditions. With his
patience and great feedback I managed to narrow down the problem and
eventually fix it although I can't test any of this myself!
problem with my CURLINFO_PRIMARY_IP fix from October 7th that caused a NULL
pointer read. I also took the opportunity to clean up this logic (storing of
the connection's IP address) somewhat as we had it stored in two different
places and ways previously and they are now unified.
make CURLOPT_PROXYUSERPWD sort of deprecated. The primary motive for adding
these new options is that they have no problems with the colon separator
that the CURLOPT_PROXYUSERPWD option does.
curl_easy_setopt: CURLOPT_USERNAME and CURLOPT_PASSWORD that sort of
deprecates the good old CURLOPT_USERPWD since they allow applications to set
the user name and password independently and perhaps more importantly allow
both to contain colon(s) which CURLOPT_USERPWD doesn't fully support.
CURLOPT_POST301 (but adds a define for backwards compatibility for you who
don't define CURL_NO_OLDIES). This option allows you to now also change the
libcurl behavior for a HTTP response 302 after a POST to not use GET in the
subsequent request (when CURLOPT_FOLLOWLOCATION is enabled). I edited the
patch somewhat before commit. The curl tool got a matching --post302
option. Test case 1076 was added to verify this.
enabling this feature with CURLOPT_CERTINFO for a request using SSL (HTTPS
or FTPS), libcurl will gather lots of server certificate info and that info
can then get extracted by a client after the request has completed with
curl_easy_getinfo()'s CURLINFO_CERTINFO option. Linus Nielsen Feltzing
helped me test and smoothen out this feature.
Unfortunately, this feature currently only works with libcurl built to use
OpenSSL.
This feature was sponsored by networking4all.com - thanks!
parser to allow numerical IPv6-addresses to be specified with the scope
given, as per RFC4007 - with a percent letter that itself needs to be URL
escaped. For example, for an address of fe80::1234%1 the HTTP URL is:
"http://[fe80::1234%251]/"
CURLINFO_APPCONNECT_TIME. This is set with the "application layer"
handshake/connection is completed (typically SSL, TLS or SSH). By using this
you can figure out the application layer's own connect time. You can extract
the time stamp using curl's -w option and the new variable named
'time_appconnect'. This feature was sponsored by Lenny Rachitsky at NeuStar.
curl_easy_getinfo. It returns a pointer to a string with the most recently
used IP address. Modified test case 500 to also verify this feature. The
implementing of this feature was sponsored by Lenny Rachitsky at NeuStar.
redirections and thus cannot use CURLOPT_FOLLOWLOCATION easily, we now
introduce the new CURLINFO_REDIRECT_URL option that lets applications
extract the URL libcurl would've redirected to if it had been told to. This
then enables the application to continue to that URL as it thinks is
suitable, without having to re-implement the magic of creating the new URL
from the Location: header etc. Test 1029 verifies it.
better control at the exact state of the connection's SSL status so that we
know exactly when it has completed the SSL negotiation or not so that there
won't be accidental re-uses of connections that are wrongly believed to be
in SSL-completed-negotiate state.
such as the CURLOPT_SSL_CTX_FUNCTION one treat that as if it was a Location:
following. The patch that introduced this feature was done for 7.11.0, but
this code and functionality has been broken since about 7.15.4 (March 2006)
with the introduction of non-blocking OpenSSL "connects".
It was a hack to begin with and since it doesn't work and hasn't worked
correctly for a long time and nobody has even noticed, I consider it a very
suitable subject for plain removal. And so it was done.
the SingleRequest one to make pipelining better. It is a bit tricky to keep
them in the right place, to keep things related to the actual request or to
the actual connection in the right place.
previously had a number of flaws, perhaps most notably when an application
fired up N transfers at once as then they wouldn't pipeline at all that
nicely as anyone would think... Test case 530 was also updated to take the
improved functionality into account.
The signalling of that a global DNS cache is wanted is done by setting the
option but the setting of the internal variable that it is in use must not be
done until it finally actually gets used!
NOTE and WARNING: I noticed that you can't actually switch off the global dns
cache with CURLOPT_DNS_USE_GLOBAL_CACHE but you couldn't do that previously
either and the option is very clearly and loudly documented as DO NOTE USE so
I won't bother to fix this bug now.
silly code left from when we switched to let the multi handle "hold" the dns
cache when using the multi interface... Of course this only triggered when a
certain function call returned error at the correct moment.
libcurl to seek in a given input stream. This is particularly important when
doing upload resumes when there's already a huge part of the file present
remotely. Before, and still if this callback isn't used, libcurl will read
and through away the entire file up to the point to where the resuming
begins (which of course can be a slow opereration depending on file size,
I/O bandwidth and more). This new function will also be preferred to get
used instead of the CURLOPT_IOCTLFUNCTION for seeking back in a stream when
doing multi-stage HTTP auth with POST/PUT.
code to instead introduce support for a new proxy type called
CURLPROXY_SOCKS5_HOSTNAME that is used to send the host name to the proxy
instead of IP address and there's thus no longer any need for a new
curl_easy_setopt() option.
The default SOCKS5 proxy is again back to sending the IP address to the
proxy. The new curl command line option for enabling sending host name to a
SOCKS5 proxy is now --socks5-hostname.
proxy do the host name resolving and only if --socks5ip (or
CURLOPT_SOCKS5_RESOLVE_LOCAL) is used we resolve the host name locally and
pass on the IP address only to the proxy.
the appending of the "type=" thing on FTP URLs when they are passed to a
HTTP proxy. Some proxies just don't like that appending (which is done
unconditionally in 7.17.1), and some proxies treat binary/ascii transfers
better with the appending done!
is inited at the start of the DO action. I removed the Curl_transfer_keeper
struct completely, and I had to move out a few struct members (that had to
be set before DO or used after DONE) to the UrlState struct. The SingleRequest
struct is accessed with SessionHandle->req.
One of the biggest reasons for doing this was the bunch of duplicate struct
members in HandleData and Curl_transfer_keeper since it was really messy to
keep track of two variables with the same name and basically the same purpose!
the same state struct as the host auth, so both could never be used at the
same time! I fixed it (without being able to check) to use two separate
structs to allow authentication using Negotiate on host and proxy
simultanouesly.
do_init() and do_complete() which now are called first and last in the DO
function. It simplified the flow in multi.c and the functions got more
sensible names!
out that SFTP requests didn't use persistent connections. Neither did SCP
ones. I gave the SSH code a good beating and now both SCP and SFTP should
use persistent connections fine. I also did a bunch for indent changes as
well as a bug fix for the "keyboard interactive" auth.
connectdata struct. This will in theory enable us to do persistent connections
with SCP+SFTP, but currently the state machine always (and wrongly) cleanup
everything in the 'done' action instead of in 'disconnect'. Also did a bunch
of indent fixes, if () => if() and a few other source cleanups like added
comments etc.
https://bugzilla.novell.com/show_bug.cgi?id=332917 about a HTTP redirect to
FTP that caused memory havoc. His work together with my efforts created two
fixes:
#1 - FTP::file was moved to struct ftp_conn, because is has to be dealt with
at connection cleanup, at which time the struct HandleData could be
used by another connection.
Also, the unused char *urlpath member is removed from struct FTP.
#2 - provide a Curl_reset_reqproto() function that frees
data->reqdata.proto.* on connection setup if needed (that is if the
SessionHandle was used by a different connection).
This happened because the tftp code always uncondionally did a bind()
without caring if one already had been done and then it failed. I wrote a
test case (1009) to verify this, but it is a bit error-prone since it will
have to pick a fixed local port number and since the tests are run on so
many different hosts in different situations I add it in disabled state.
CURLOPT_OPENSOCKETDATA to set a callback that allows an application to replace
the socket() call used by libcurl. It basically allows the app to change
address, protocol or whatever of the socket. (I also did some whitespace
indent/cleanups in lib/url.c which kind of hides some of these changes, sorry
for mixing those in.)
CURLOPT_SSH_HOST_PUBLIC_KEY_MD5 and the curl tool --hostpubmd5. They both make
the SCP or SFTP connection verify the remote host's md5 checksum of the public
key before doing a connect, to reduce the risk of a man-in-the-middle attack.
curl_easy_setopt() that alters how libcurl functions when following
redirects. It makes libcurl obey the RFC2616 when a 301 response is received
after a non-GET request is made. Default libcurl behaviour is to change
method to GET in the subsequent request (like it does for response code 302
- because that's what many/most browsers do), but with this CURLOPT_POST301
option enabled it will do what the spec says and do the next request using
the same method again. I.e keep POST after 301.
The curl tool got this option as --post301
Test case 1011 and 1012 were added to verify.
CURLOPT_NOBODY enabled but not CURLOPT_HEADER, libcurl wouldn't do TYPE
before it does SIZE which makes it less useful. I walked over the code and
made it do this properly, and added test case 542 to verify it.
o It looks for the NSS database first in the environment variable SSL_DIR,
then in /etc/pki/nssdb, then it initializes with no database if neither of
those exist.
o If the NSS PKCS#11 libnspsem.so driver is available then PEM files may be
loaded, including the ca-bundle. If it is not available then only
certificates already in the NSS database are used.
o Tries to detect whether a file or nickname is being passed in so the right
thing is done
o Added a bit of code to make the output more like the OpenSSL module,
including displaying the certificate information when connecting in
verbose mode
o Improved handling of certificate errors (expired, untrusted, etc)
The libnsspem.so PKCS#11 module is currently only available in Fedora
8/rawhide. Work will be done soon to upstream it. The NSS module will work
with or without it, all that changes is the source of the certificates and
keys.
passed to it with curl_easy_setopt()! Previously it has always just refered
to the data, forcing the user to keep the data around until libcurl is done
with it. That is now history and libcurl will instead clone the given
strings and keep private copies.
and CURLOPT_NEW_DIRECTORY_PERMS. These control the premissions for files
and directories created on the remote server. CURLOPT_NEW_FILE_PERMS
defaults to 0644 and CURLOPT_NEW_DIRECTORY_PERMS defaults to 0755
libssh2_sftp_shutdown() and libssh2_session_free() can now return
LIBSSH2_ERROR_EAGAIN.
* Fix the _send() and _recv() return values so non-blocking works
function that deprecates the curl_multi_socket() function. Using the new
function the application tell libcurl what action that was found in the
socket that it passes in. This gives a significant performance boost as it
allows libcurl to avoid a call to poll()/select() for every call to
curl_multi_socket*().
"case label value exceeds maximum value for type" and
"comparison is always false due to limited range of data type"
Both triggered when using a bool variable as the switch variable
in a switch statement and using enums for the case targets.
to the debug callback.
- Shmulik Regev added CURLOPT_HTTP_CONTENT_DECODING and
CURLOPT_HTTP_TRANSFER_DECODING that if set to zero will disable libcurl's
internal decoding of content or transfer encoded content. This may be
preferable in cases where you use libcurl for proxy purposes or similar. The
command line tool got a --raw option to disable both at once.
and CURLOPT_CONNECTTIMEOUT_MS that, as their names should hint, do the
timeouts with millisecond resolution instead. The only restriction to that
is the alarm() (sometimes) used to abort name resolves as that uses full
seconds. I fixed the FTP response timeout part of the patch.
Internally we now count and keep the timeouts in milliseconds but it also
means we multiply set timeouts with 1000. The effect of this is that no
timeout can be set to more than 2^31 milliseconds (on 32 bit systems), which
equals 24.86 days. We probably couldn't before either since the code did
*1000 on the timeout values on several places already.
doing an FTP transfer is removed from a multi handle before completion. The
fix also fixed the "alive counter" to be correct on "premature removal" for
all protocols.
curl that uses the new CURLOPT_FTP_SSL_CCC option in libcurl. If enabled, it
will make libcurl shutdown SSL/TLS after the authentication is done on a
FTP-SSL operation.
get confused and not acknowledge the 'no_proxy' variable properly once it
had used the proxy and you re-used the same easy handle. I made sure the
proxy name is properly stored in the connect struct rather than the
sessionhandle/easy struct.
(http://curl.haxx.se/bug/view.cgi?id=1618359) and subsequently provided a
patch for it: when downloading 2 zero byte files in a row, curl 7.16.0
enters an infinite loop, while curl 7.16.1-20061218 does one additional
unnecessary request.
Fix: During the "Major overhaul introducing http pipelining support and
shared connection cache within the multi handle." change, headerbytecount
was moved to live in the Curl_transfer_keeper structure. But that structure
is reset in the Transfer method, losing the information that we had about
the header size. This patch moves it back to the connectdata struct.
(http://curl.haxx.se/bug/view.cgi?id=1603712) which is about connections
getting cut off prematurely when --limit-rate is used. While I found no such
problems in my tests nor in my reading of the code, I found that the
--limit-rate code was severly flawed (since it was moved into the lib, since
7.15.5) when used with the easy interface and it didn't work as documented so
I reworked it somewhat and now it works for my tests.
KNOWN_BUGS #25, which happens when a proxy closes the connection when
libcurl has sent CONNECT, as part of an authentication negotiation. Starting
now, libcurl will re-connect accordingly and continue the authentication as
it should.
would crash if a bad function sequence was used when shutting down after
using the multi interface (i.e using easy_cleanup after multi_cleanup) so
precautions have been added to make sure it doesn't any more - test case 529
was added to verify.
handle that is part of a multi handle first removes the handle from the
stack.
- Added CURLOPT_SSL_SESSIONID_CACHE and --no-sessionid to disable SSL
session-ID re-use on demand since there obviously are broken servers out
there that misbehave with session-IDs used.
problem with it (SIGSEGV-style). It clearly showed that the existing
socket-state and state-difference function wasn't good enough so I rewrote
it and could then re-run Jeff's program without any crash. The previous
version clearly could miss to tell the application when a handle changed
from using one socket to using another.
While I was at it (as I could use this as a means to track this problem
down), I've now added a 'magic' number to the easy handle struct that is
inited at curl_easy_init() time and cleared at curl_easy_cleanup() time that
we can use internally to detect that an easy handle seems to be fine, or at
least not closed or freed (freeing in debug builds fill the area with 0x13
bytes but in normal builds we can of course not assume any particular data
in the freed areas).
the crash was that libcurl internally was a bit confused about who owned the
DNS cache at all times so if you created an easy handle that uses a shared
DNS cache and added that to a multi handle it would crash. Now we keep more
careful internal track of exactly what kind of DNS cache each easy handle
uses: None, Private (allocated for and used only by this single handle),
Shared (points to a cache held by a shared object), Global (points to the
global cache) or Multi (points to the cache within the multi handle that is
automatically shared between all easy handles that are added with private
caches).
CURLOPT_MAX_RECV_SPEED_LARGE that limit tha maximum rate libcurl is allowed
to send or receive data. This kind of adds the the command line tool's
option --limit-rate to the library.
The rate limiting logic in the curl app is now removed and is instead
provided by libcurl itself. Transfer rate limiting will now also work for -d
and -F, which it didn't before.
(http://curl.haxx.se/mail/lib-2006-02/0154.html) by adding the NTLM hash
function in addition to the LM one and making some other adjustments in the
order the different parts of the data block are sent in the Type-2 reply.
Inspiration for this work was taken from the Firefox NTLM implementation.
I edited the existing 21(!) NTLM test cases to run fine with these news. Due
to the fact that we now properly include the host name in the Type-2 message
the test cases now only compare parts of that chunk.
with the multi interface and multi-part formposts. The fix from February
22nd could make the Curl_done() function get called twice on the same
connection and it was not designed for that and thus tried to call free() on
an already freed memory area!
an app can use to let libcurl only connect to a remote host and then extract
the socket from libcurl. libcurl will then not attempt to do any transfer at
all after the connect is done.
curl tool with --local-port. Plain and simply set the range of ports to bind
the local end of connections to. Implemented on to popular demand.
Not extensively tested. Please let me know how it works.
(CURLOPT_FTPPORT) didn't work for ipv6-enabed curls if the IP wasn't a
"native" IP while it works fine for ipv6-disabled builds!
In the process of fixing this, I removed the support for LPRT since I can't
think of many reasons to keep doing it and asking on the mailing list didn't
reveal anyone else that could either. The code that sends EPRT and PORT is
now also a lot simpler than before (IMHO).
given subdirs, libcurl would still "remember" the full path as if it is the
current directory libcurl is in so that the next curl_easy_perform() would
get really confused if it tried the same path again - as it would not issue
any CWD commands at all, assuming it is already in the "proper" dir.
Starting now, a failed CWD command sets a flag that prevents the path to be
"remembered" after returning.
(http://curl.haxx.se/bug/view.cgi?id=1338648) which really is more of a
feature request, but anyway. It pointed out that --max-redirs did not allow
it to be set to 0, which then would return an error code on the first
Location: found. Based on Nis' patch, now libcurl supports CURLOPT_MAXREDIRS
set to 0, or -1 for infinity. Added test case 274 to verify.
from the command line tool with --ignore-content-length. This will make it
easier to download files from Apache 1.x (and similar) servers that are
still having problems serving files larger than 2 or 4 GB. When this option
is enabled, curl will simply have to wait for the server to close the
connection to signal end of transfer. I wrote test case 269 that runs a
simple test that this works.
.netrc, and when following a Location: the subsequent requests didn't properly
use the auth as found in the netrc file. Added test case 257 to verify my fix.
internally, with code provided by sslgen.c. All SSL-layer-specific code is
then written in ssluse.c (for OpenSSL) and gtls.c (for GnuTLS).
As far as possible, internals should not need to know what SSL layer that is
in use. Building with GnuTLS currently makes two test cases fail.
TODO.gnutls contains a few known outstanding issues for the GnuTLS support.
GnuTLS support is enabled with configure --with-gnutls
USE_WINDOWS_SSPI on Windows, and then libcurl will be built to use the native
way to do NTLM. SSPI also allows libcurl to pass on the current user and its
password in the request.
curl_easy_perform() invokes. It was previously unlocked at disconnect, which
could mean that it remained locked between multiple transfers. The DNS cache
may not live as long as the connection cache does, as they are separate.
To deal with the lack of DNS (host address) data availability in re-used
connections, libcurl now keeps a copy of the IP adress as a string, to be able
to show it even on subsequent requests on the same connection.
present in RFC959... so now (lib)curl supports it as well. --ftp-account and
CURLOPT_FTP_ACCOUNT set the account string. (The server may ask for an account
string after PASS have been sent away. The client responds with "ACCT [account
string]".) Added test case 228 and 229 to verify the functionality. Updated
the test FTP server to support ACCT somewhat.
#1098843. In short, a shared DNS cache was setup for a multi handle and when
the shared cache was deleted before the individual easy handles, the latter
cleanups caused read/writes to already freed memory.
If EPSV, EPRT or LPRT is tried and doesn't work, it will not be retried on
the same server again even if a following request is made using a persistent
connection.
If a second request is made to a server, requesting a file from the same
directory as the previous request operated on, libcurl will no longer make
that long series of CWD commands just to end up on the same spot. Note that
this is only for *exactly* the same dir. There is still room for improvements
to optimize the CWD-sending when the dirs are only slightly different.
Added test 210, 211 and 212 to verify these changes. Had to improve the
test script too and added a new primitive to the test file format.
app to retrieve the errno variable after a (connect) failure. It will make
sense to provide this for more failures in a more generic way, but let's
start like this.