When we're uploading using FTP and the server issues a tiny pause
between opening the connection to the client's secondary socket, the
client's initial poll() times out, which leads to second poll() which
does not wait for POLLIN on the secondary socket. So that poll() also
has to time out, creating a long (200ms) pause.
This patch adds the correct flag to the secondary socket, making the
second poll() correctly wait for the connection there too.
Signed-off-by: Ales Novak <alnovak@suse.cz>
Closes#978
curl_printf.h defines printf to curl_mprintf, etc. This can cause
problems with external headers which may use
__attribute__((format(printf, ...))) markers etc.
To avoid that they cause problems with system includes, we include
curl_printf.h after any system headers. That makes the three last
headers to always be, and we keep them in this order:
curl_printf.h
curl_memory.h
memdebug.h
None of them include system headers, they all do funny #defines.
Reported-by: David Benjamin
Fixes#743
... as it implies we need to check for that on all the other variable
references as well (as Coverity otherwise warns us for missing NULL
checks), and we're alredy making sure that the pointer is never NULL.
They tend to never get updated anyway so they're frequently inaccurate
and we never go back to revisit them anyway. We document issues to work
on properly in KNOWN_BUGS and TODO instead.
... and assign it from the set.fread_func_set pointer in the
Curl_init_CONNECT function. This A) avoids that we have code that
assigns fields in the 'set' struct (which we always knew was bad) and
more importantly B) it makes it impossibly to accidentally leave the
wrong value for when the handle is re-used etc.
Introducing a state-init functionality in multi.c, so that we can set a
specific function to get called when we enter a state. The
Curl_init_CONNECT is thus called when switching to the CONNECT state.
Bug: https://github.com/bagder/curl/issues/346Closes#346
In some timing-dependnt cases when a 4xx response immediately followed
after a 150 when a STOR was issued, this function would wrongly return
'complete == true' while 'wait_data_conn' was still set.
Closes#405
Reported-by: Patricia Muscalu
The multi state machine would otherwise go into the DO_MORE state after
DO, even for the case when the FTP state machine had already performed
those duties, which caused libcurl to get stuck in that state and fail
miserably. This occured for for active ftp uploads.
Reported-by: Patricia Muscalu
** WORK-AROUND **
The introduced non-blocking general behaviour for Curl_proxyCONNECT()
didn't work for the data connection establishment unless it was very
fast. The newly introduced function argument makes it operate in a more
blocking manner, more like it used to work in the past. This blocking
approach is only used when the FTP data connecting through HTTP proxy.
Blocking like this is bad. A better fix would make it work more
asynchronously.
Bug: https://github.com/bagder/curl/issues/278
With many easy handles using the same connection for multiplexing, it is
important we store and keep the transfer-oriented stuff in the
SessionHandle so that callbacks and callback data work fine even when
many easy handles share the same physical connection.
Since we just started make use of free(NULL) in order to simplify code,
this change takes it a step further and:
- converts lots of Curl_safefree() calls to good old free()
- makes Curl_safefree() not check the pointer before free()
The (new) rule of thumb is: if you really want a function call that
frees a pointer and then assigns it to NULL, then use Curl_safefree().
But we will prefer just using free() from now on.
The function "free" is documented in the way that no action shall occur for
a passed null pointer. It is therefore not needed that a function caller
repeats a corresponding check.
http://stackoverflow.com/questions/18775608/free-a-null-pointer-anyway-or-check-first
This issue was fixed by using the software Coccinelle 1.0.0-rc24.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
... and make sure we can connect the data connection to a host name that
is longer than 48 bytes.
Also simplifies the code somewhat by re-using the original host name
more, as it is likely still in the DNS cache.
Original-Patch-by: Vojtěch Král
Bug: http://curl.haxx.se/bug/view.cgi?id=1468
For consistency, as we seem to have a bit of a mixed bag, changed all
instances of ipv4 and ipv6 in comments and documentations to use the
correct case.
There was a confusion between these: this commit tries to disambiguate them.
- Scope can be computed from the address itself.
- Scope id is scope dependent: it is currently defined as 1-based local
interface index for link-local scoped addresses, and as a site index(?) for
(obsolete) site-local addresses. Linux only supports it for link-local
addresses.
The URL parser properly parses a scope id as an interface index, but stores it
in a field named "scope": confusion. The field has been renamed into "scope_id".
Curl_if2ip() used the scope id as it was a scope. This caused failures
to bind to an interface.
Scope is now computed from the addresses and Curl_if2ip() matches them.
If redundantly specified in the URL, scope id is check for mismatch with
the interface index.
This commit should fix SF bug #1451.
... for the local variable name in functions holding the return
code. Using the same name universally makes code easier to read and
follow.
Also, unify code for checking for CURLcode errors with:
if(result) or if(!result)
instead of
if(result == CURLE_OK), if(CURLE_OK == result) or if(result != CURLE_OK)
Historically the default "unknown" value for progress.size_dl and
progress.size_ul has been zero, since these values are initialized
implicitly by the calloc that allocates the curl handle that these
variables are a part of. Users of curl that install progress
callbacks may expect these values to always be >= 0.
Currently it is possible for progress.size_dl and progress.size_ul
to by set to a value of -1, if Curl_pgrsSetDownloadSize() or
Curl_pgrsSetUploadSize() are passed a "size" of -1 (which a few
places currently do, and a following patch will add more). So
lets update Curl_pgrsSetDownloadSize() and Curl_pgrsSetUploadSize()
so they make sure that these variables always contain a value that
is >= 0.
Updates test579 and test599.
Signed-off-by: Brandon Casey <drafnel@gmail.com>
Make all code use connclose() and connkeep() when changing the "close
state" for a connection. These two macros take a string argument with an
explanation, and debug builds of curl will include that in the debug
output. Helps tracking connection re-use/close issues.
set.infilesize in this case was modified in several places, which could
lead to repeated requests using the same handle to get unintendent/wrong
consequences based on what the previous request did!
This makes the findprotocol() function work as intended so that libcurl
can properly be restricted to not support HTTP while still supporting
HTTPS - since the HTTPS handler previously set both the HTTP and HTTPS
bits in the protocol field.
This fixes --proto and --proto-redir for most SSL protocols.
This is done by adding a few new convenience defines that groups HTTP
and HTTPS, FTP and FTPS etc that should then be used when the code wants
to check for both protocols at once. PROTO_FAMILY_[protocol] style.
Bug: https://github.com/bagder/curl/pull/97
Reported-by: drizzt
When doing passive FTP, the multi state function needs to extract and
use the happy eyeballs sockets to wait for to check for completion!
Bug: http://curl.haxx.se/mail/lib-2014-02/0135.html (ruined)
Reported-by: Alan
Following commit 0aafd77fa4, replaced the internal usage of
FORMAT_OFF_T and FORMAT_OFF_TU with the external versions that we
expect API programmers to use.
This negates the need for separate definitions which were subtly
different under different platforms/compilers.
This patch adds a 200ms delay between the first and second address
family socket connection attempts.
It also iterates over IP addresses in the order returned by the
system, meaning most dual-stack systems will try IPv6 first.
Additionally, it refactors the connect code, removing most code that
handled synchronous connects. Since all sockets are now non-blocking,
the logic can be made simpler.
This patch invokes two socket connect()s nearly simultaneously, and
the socket that is first connected "wins" and is subsequently used for
the connection. The other is terminated.
There is a very slight IPv4 preference, in that if both sockets connect
simultaneously IPv4 is checked first and thus will win.
This is a regression since the switch to always-multi internally
c43127414d.
Test 1316 was modified since we now clearly call the Curl_client_write()
function when doing the LIST transfer part and then the
handler->protocol says FTP and ftpc.transfertype is 'A' which implies
text converting even though that the response is initially a HTTP
CONNECT response in this case.
I brought back security.h in commit bb55293313. As we actually
already found out back in 2005 in commit 62970da675, the file name
security.h causes problems so I renamed it curl_sec.h instead.
We've announced this pending removal for a long time and we've
repeatedly asked if anyone would care or if anyone objects. Nobody has
objected. It has probably not even been working for a good while since
nobody has tested/used this code recently.
The stuff in krb4.h that was generic enough to be used by other sources
is now present in security.h
This makes the socket callback get called with the proper bitmask as
otherwise the application could be left hanging waiting for reading on
an upload connection!
Bug: http://curl.haxx.se/mail/lib-2013-08/0043.html
Reported-by: Bill Doyle
All protocol handler structs are now opaque (void *) in the
SessionHandle struct and moved in the request-specific sub-struct
'SingleRequest'. The intension is to keep the protocol specific
knowledge in their own dedicated source files [protocol].c etc.
There's some "leakage" where this policy is violated, to be addressed at
a later point in time.
1 - always allocate the struct in protocol->setup_connection. Some
protocol handlers had to get this function added.
2 - always free at the end of a request. This is also an attempt to keep
less memory in the handle after it is completed.
The previous naming scheme ftp_state_post_XXXX() wasn't really helpful
as it wasn't always immediately after 'xxxx' and it wasn't easy to
understand what it does based on such a name.
This new one is instead ftp_state_yyyy() where yyyy describes what it
does or sends.
This is a regression as this logic used to work. It isn't clear when it
broke, but I'm assuming in 7.28.0 when we went all-multi internally.
This likely never worked with the multi interface. As the failed
connection is detected once the multi state has reached DO_MORE, the
Curl_do_more() function was now expanded somewhat so that the
ftp_do_more() function can request to go "back" to the previous state
when it makes another attempt - using PASV.
Added test case 1233 to verify this fix. It has the little issue that it
assumes no service is listening/accepting connections on port 1...
Reported-by: byte_bucket in the #curl IRC channel
In the case of an active connection when ftp_do_more() detects that the
server has connected back, it must make sure to mark it as complete so
that the multi_runsingle() function will detect this and move on to the
next state.
Bug: http://curl.haxx.se/mail/lib-2013-07/0115.html
Reported-by: Clemens Gruber
When connecting back to an FTP server after having sent PASV/EPSV,
libcurl sometimes didn't use the proxy properly even though the proxy
was used for the initial connect.
The function wrongly checked for the CURLOPT_PROXY variable to be set,
which made it act wrongly if the proxy information was set with an
environment variable.
Added test case 711 to verify (based on 707 which uses --socks5). Also
added test712 to verify another variation of setting the proxy: with
--proxy socks5://
Bug: http://curl.haxx.se/bug/view.cgi?id=1218
Reported-by: Zekun Ni
...instead of the 220 we otherwise expect.
Made the ftpserver.pl support sending a custom "welcome" and then
created test 1219 to verify this fix with such a 230 welcome.
Bug: http://curl.haxx.se/mail/lib-2013-02/0102.html
Reported by: Anders Havn
Accessing a file with an absolute path in the root dir but with no
directory specified was not handled correctly. This fix comes with four
new test cases that verify it.
Bug: http://curl.haxx.se/mail/lib-2013-04/0142.html
Reported by: Sam Deane
When doing PWD, there's a 257 response which apparently some servers
prefix with a comment before the path instead of after it as is
otherwise the norm.
Failing to parse this, several otherwise legitimate use cases break.
Bug: http://curl.haxx.se/mail/lib-2013-04/0113.html
When doing PORT and upload (STOR), this function needs to extract the
file descriptor for both connections so that it will respond immediately
when the server eventually connects back.
This flaw caused active connections to become unnecessary slow but they
would still often work due to the normal polling on a timeout. The bug
also would not occur if the server connected back very fast, like when
testing on local networks.
Bug: http://curl.haxx.se/bug/view.cgi?id=1183
Reported by: Daniel Theron
I am using curl_easy_setopt(CURLOPT_INTERFACE, "if!something") to force
transfers to use a particular interface but the transfer fails with
CURLE_INTERFACE_FAILED, "Failed binding local connection end" if the
interface I specify has no IPv6 address. The cause is as follows:
The remote hostname resolves successfully and has an IPv6 address and an
IPv4 address.
cURL attempts to connect to the IPv6 address first.
bindlocal (in lib/connect.c) fails because Curl_if2ip cannot find an
IPv6 address on the interface.
This is a fatal error in singleipconnect()
This change will make cURL try the next IP address in the list.
Also included are two changes related to IPv6 address scope:
- Filter the choice of address in Curl_if2ip to only consider addresses
with the same scope ID as the connection address (mismatched scope for
local and remote address does not result in a working connection).
- bindlocal was ignoring the scope ID of addresses returned by
Curl_if2ip . Now it uses them.
Bug: http://curl.haxx.se/bug/view.cgi?id=1189
The last remaining code piece that still used FTPSENDF now uses PPSENDF.
In the problematic case, a PREQUOTE series was done on a re-used
connection when Curl_pp_init() hadn't been called so it had messed up
pointers. The init call is done properly from Curl_pp_sendf() so this
change fixes this particular crash.
Bug: http://curl.haxx.se/mail/lib-2013-03/0319.html
Reported by: Sam Deane
The list of unsafe functions currently consists of sprintf, vsprintf,
strcat, strncat and gets.
Subsequently, some existing code needed updating to avoid warnings on
this.
... since they're not used by the easy interface really, I wanted to
remove the association. Also, I unified the pingpong statemachine driver
into a single function with a 'wait' argument: Curl_pp_statemach.
Reworked the pp->endofresp() function so that the conndata, line and
line length are passed down to it just as with Curl_client_write()
rather than each implementation of the function having to query
these values.
Additionally changed the int return type to bool as this is more
representative of the function's usage.
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
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.
This reverts renaming and usage of lib/*.h header files done
28-12-2012, reverting 2 commits:
f871de0... build: make use of 76 lib/*.h renamed files
ffd8e12... build: rename 76 lib/*.h files
This also reverts removal of redundant include guard (redundant thanks
to changes in above commits) done 2-12-2013, reverting 1 commit:
c087374... curl_setup.h: remove redundant include guard
This also reverts renaming and usage of lib/*.c source files done
3-12-2013, reverting 3 commits:
13606bb... build: make use of 93 lib/*.c renamed files
5b6e792... build: rename 93 lib/*.c files
7d83dff... build: commit 13606bbfde follow-up 1
Start of related discussion thread:
http://curl.haxx.se/mail/lib-2013-01/0012.html
Asking for confirmation on pushing this revertion commit:
http://curl.haxx.se/mail/lib-2013-01/0048.html
Confirmation summary:
http://curl.haxx.se/mail/lib-2013-01/0079.html
NOTICE: The list of 2 files that have been modified by other
intermixed commits, while renamed, and also by at least one
of the 6 commits this one reverts follows below. These 2 files
will exhibit a hole in history unless git's '--follow' option
is used when viewing logs.
lib/curl_imap.h
lib/curl_smtp.h
As pointed out in Bug report #3579064, curl_multi_perform() would
wrongly use a blocking mechanism internally for some commands which
could lead to for example a very long block if the LIST response never
showed.
The solution was to make sure to properly continue to use the multi
interface non-blocking state machine.
The new test 1501 verifies the fix.
Bug: http://curl.haxx.se/bug/view.cgi?id=3579064
Reported by: Guido Berhoerster
Commit b91d29a28e170c16d65d956db79f2cd3a82372d2 introduces a bug and breaks Curl_closesocket function. sock_accepted flag for the second socket should be tagged as TRUE before the sockopt callback is called because in case the callback returns an error, Curl_closesocket function is going to call the - fclosesocket - callback for the accept()ed socket
For active FTP connections, applications may need setting the sockopt after accept() call returns successful. This fix gives a call to the callback registered with CURL_SOCKOPTFUNCTION option. Also a new sock type - CURLSOCKTYPE_ACCEPT - is added. This type is to be passed to application callbacks with - purpose - parameter. Applications may use this parameter to distinguish between socket types.
Fixed warning: dereferencing pointer does break strict-aliasing rules
by using a union instead of separate pointer variables.
Internal union sockaddr_u could probably be moved to generic header.
Thanks to Paul Howarth for the hint about using unions for this.
Important for winbuild: Separate declaration of sockaddr_u pointer.
The pointer variable *sock cannot be declared and initialized right
after the union declaration. Therefore it has to be a separate statement.
Curl_protocol_connect() now does the tunneling through the HTTP proxy if
requested instead of letting each protocol specific connection function
do it.
ftp_do_more() returns after accepting the server connect however it
needs to fall through and set "*complete" to TRUE before exit from the
function.
Bug: http://curl.haxx.se/mail/lib-2011-12/0250.html
Reported by: Gokhan Sengun
First off the timeout for accepting a server connect back must of course
respect a global timeout. Then the timeleft function is only used by ftp
code so it was moved to ftp.c and made static.
"wait_data_conn" was added to the connectionbits in commit c834213ad5 for
handling active FTP connections but as it is purely FTP specific and now
only ever accessed by ftp.c I moved it into the FTP connection struct.
Backpedaled out the funny double-change of state in the multi state
machine by adding a new argument to the do_more() function to signal
completion. This way it can remain in the DO_MORE state properly until
done. Long term, the entire DO_MORE logic should be moved into the FTP
code and be hidden from the multi code as the logic is only used for
FTP.
1- Two new error codes are introduced.
CURLE_FTP_ACCEPT_FAILED to be set whenever ACCEPTing fails because of
FTP server connected.
CURLE_FTP_ACCEPT_TIMEOUT to be set whenever ACCEPTing timeouts.
Neither of these errors are considered fatal and control connection
remains OK because it could just be a firewall blocking server to
connect to the client.
2- One new setopt option was introduced.
CURLOPT_ACCEPTTIMEOUT_MS
It sets the maximum amount of time FTP client is going to wait for a
server to connect. Internal default accept timeout is 60 seconds.
Keep track of which sockets that are the result of accept() calls and
refuse to call the closesocket callback for those sockets. Test case 596
now verifies that the open socket callback is called the same number of
times as the closed socket callback for active FTP connections.
Bug: http://curl.haxx.se/mail/lib-2011-12/0018.html
Reported by: Gokhan Sengun
When the new socket is created for an active connection, it is now done
using the open socket callback.
Test case 596 was modified to run fine, although it hides the fact that
the close callback is still called too many times, as it also gets
called for closing sockets that were created with accept().
By setting PROTOPT_NOURLQUERY in the protocol handler struct, the
protocol will get the "query part" of the URL cut off before the data is
handled by the protocol-specific code. This makes libcurl adhere to
RFC3986 section 2.2.
Test 1220 is added to verify a file:// URL with query-part.
When the user requests PORT with a specific port or port range, the code
could lock up in an endless loop. There's now an extra conditional that
makes sure to special treat the error and try the local address only
once so a second failure will abort the loop correctly.
Bug: http://curl.haxx.se/bug/view.cgi?id=3433968
Reported by: Gokhan Sengun
Now called 'use_ssl' instead, which better matches the current CURLOPT
name and since the option is used for all pingpong protocols (at least)
it makes sense to not use 'ftp' in the name.
After a PORT has been issued, and the multi handle would switch to the
CURLM_STATE_DO_MORE state (which is unique for FTP), libcurl would
return the wrong fdset to wait for when curl_multi_fdset() is
called. The code would blindly assume that it was waiting for a connect
of the second connection, while that isn't true immediately after the
PORT command.
Also, the function multi.c:domore_getsock() was highly FTP-centric and
therefore ugly to keep in protocol-agnostic code. I solved this problem
by introducing a new function pointer in the Curl_handler struct called
domore_getsock() which is only called during the DOMORE state for
protocols that set that pointer.
The new ftp.c:ftp_domore_getsock() function now returns fdset info about
the control connection's command/response handling while such a state is
in use, and goes over to waiting for a writable second connection first
once the commands are done.
The original problem could be seen by running test 525 and checking the
time stamps in the FTP server log. I can verify that this fix at least
fixes this problem.
Bug: http://curl.haxx.se/mail/lib-2011-10/0250.html
Reported by: Gokhan Sengun
When using the multi interface, a SOCKS proxy, and a connection that
wouldn't immediately consider itself connected (which my Linux tests do
by default), libcurl would be tricked into doing _two_ connects to the
SOCKS proxy when it setup the data connection and then of course the
second attempt would fail miserably and cause error.
This problem is a regression that was introduced by commit
4a42e5cdaa that was introduced in the 7.21.7 release.
Bug: http://curl.haxx.se/mail/lib-2011-08/0199.html
Reported by: Fabian Keil
Introduced the initial setup to allow closesocket callbacks by making
sure sclose() is only ever called from one place in the libcurl source
and still run all test cases fine.
The protocol handler's flags field now can set that the protocol
requires a password, so that the set_userpass function doesn't have to
have the specific knowledge of which protocols that do.
asyn-ares.c and asyn-thread.c are two separate backends that implement
the same (internal) async resolver API for libcurl to use. Backend is
specified at build time.
The internal resolver API is defined in asyn.h for asynch resolvers.
Stop the abuse of CURLE_FAILED_INIT as return code for things not being
init related by introducing two new return codes:
CURLE_NOT_BUILT_IN and CURLE_UNKNOWN_OPTION
CURLE_NOT_BUILT_IN replaces return code 4 that has been obsoleted for
several years. It is used for returning error when something is
attempted to be used but the feature/option was not enabled or
explictitly disabled at build-time. Getting this error mostly means that
libcurl needs to be rebuilt.
CURLE_FAILED_INIT is now saved and used strictly for init
failures. Getting this problem means something went seriously wrong,
like a resource shortage or similar.
CURLE_UNKNOWN_OPTION is the option formerly known as
CURLE_UNKNOWN_TELNET_OPTION (and the old name is still present,
separately defined to be removed in a very distant future). This error
code is meant to be used to return when an option is given to libcurl
that isn't known. This problem would mostly indicate a problem in the
program that uses libcurl.
In my attempts to reduce #ifdefs in code, the SOCKS functions are now
macros when libcurl is built without proxy support and therefore the FTP
code could avoid some #ifs.
The new http_proxy.* files now host HTTP proxy specific code (500+ lines
moved out from http.c), and as a consequence there is a macro introduced
for the Curl_proxyCONNECT() function so that code can use it without
actually supporting proxy (or HTTP) in builds.
The PROT_* set of internal defines for the protocols is no longer
used. We now use the same bits internally as we have defined in the
public header using the CURLPROTO_ prefix. This is for simplicity and
because the PROT_* prefix was already used duplicated internally for a
set of KRB4 values.
The PROTOPT_* defines were moved up to just below the struct definition
within which they are used.
The protocol handler struct got a 'flags' field for special information
and characteristics of the given protocol.
This now enables us to move away central protocol information such as
CLOSEACTION and DUALCHANNEL from single defines in a central place, out
to each protocol's definition. It also made us stop abusing the protocol
field for other info than the protocol, and we could start cleaning up
other protocol-specific things by adding flags bits to set in the
handler struct.
The "protocol" field connectdata struct was removed as well and the code
now refers directly to the conn->handler->protocol field instead. To
make things work properly, the code now always store a conn->given
pointer that points out the original handler struct so that the code can
learn details from the original protocol even if conn->handler is
modified along the way - for example when switching to go over a HTTP
proxy.
Instead of polluting many places with #ifdefs, we create a single place
for this function, and also check return code properly so that a NULL
pointer returned won't cause problems.
It helps to prevent a hangup with some FTP servers in case idle session
timeout has exceeded. But it may be useful also for other protocols
that send any quit message on disconnect. Currently used by FTP, POP3,
IMAP and SMTP.
While changing Curl_sec_read_msg to accept an enum protection_level
instead of an int, I went ahead and fixed the usage of the associated
fields.
Some code was assuming that prot_clear == 0. Fixed those to use the
proper value. Added assertions prior to any code that would set the
protection level.
