Starting now, we unconditionally use the internal replacement functions
for send() and recv() - creatively named _libssh2_recv() and
_libssh2_send().
On errors, these functions return the negative 'errno' value instead of
the traditional -1. This design allows systems that have no "natural"
errno support to not have to invent it. It also means that no code
outside of these two transfer functions should use the errno variable.
When SCP send or recv fails, it gets a special message from the server
with a warning or error message included. We have no current API to
expose that message but the foundation is there. Removed unnecessary use
of session struct fields.
I added size checks in several places. I fixed the code flow to be easier
to read in some places.
I removed unnecessary zeroing of structs. I removed unused struct fields.
We don't like magic numbers in the code. Now the acceptable failure
codes sent in the SSH_MSG_CHANNEL_OPEN_FAILURE message are added as
defined values in the private header file.
The sftp_write function shouldn't assume that the buffer pointer will be
the same in subsequent calls, even if it assumes that the data already
passed in before haven't changed.
The sftp structs are now moved to sftp.h (which I forgot to add before)
sftp_write was rewritten to split up outgoing data into multiple packets
and deal with the acks in a more asynchronous manner. This is meant to
help overcome latency and round-trip problems with the SFTP protocol.
Neither _libssh2_channel_write nor sftp_write now have the 32500 size
limit anymore and instead the channel writing function now has its own
logic to send data in multiple calls until everything is sent.
The new function takes two data areas, combines them and sends them as a
single SSH packet. This allows several functions to allocate and copy
less data.
I also found and fixed a mixed up use of the compression function
arguments that I introduced in my rewrite in a recent commit.
We now allow libssh2_session_flag() to enable compression with a new
flag and I added documentation for the previous LIBSSH2_FLAG_SIGPIPE
flag which I wasn't really aware of!
In the transport functions we avoid a strcmp() now and just check a
boolean instead.
The compress/decompress function's return code is now acknowledged and
used as actual return code in case of failures.
The LIBSSH2_DEBUG macro, defined in libssh2_priv.h, incorrectly uses the
function variable ssh_msg_disconnect when it should use ssh_msg_debug.
This shows that the LIBSSH2_CALLBACK_DEBUG callback never has worked...
'last_errno' holds to the error code from the SFTP protocol and
since that is 32 bits on the wire there's no point in using a
long for this internally which is larger on some platforms.
There was some stub-like parts of an implementation for
implementing kex language negotiation that caused clang-analyzer
to warn and as it did nothing I've now removed the dead code.
The clang-analyzer report made it look into this function and
I've went through it to remove a potential use of an
uninitialized variable and I also added some validation of input
data received from the server.
In general, lots of more code in this file need to validate the
input before assuming it is correct: there are servers out there
that have bugs or just have another idea of how to do the SFTP
protocol.
To get the blocking vs non-blocking to work as smooth as possible
and behave better internally, we avoid using the external
interfaces when calling functions internally.
Renamed a few internal functions to use _libssh2 prefix when not
being private within a file, and removed the libssh2_ for one
that was private within the file.
This was triggered by a clang-analyzer complaint that turned out
to be valid, and it made me dig deeper and fix some generic non-
blocking problems I disovered in the code.
While cleaning this up, I moved session-specific stuff over to a
new session.h header from the libssh2_priv.h header.
I'll introduce a new internal function set named
_libssh2_store_u32
_libssh2_store_u64
_libssh2_store_str
That can be used all through the library to build binary outgoing
packets. Using these instead of the current approach removes
hundreds of lines from the library while at the same time greatly
enhances readability. I've not yet fully converted everything to
use these functions.
I've converted LOTS of 'unsigned long' to 'size_t' where
data/string lengths are dealt with internally. This is The Right
Thing and it will help us make the transition to our
size_t-polished API later on as well.
I'm removing the PACKET_* error codes. They were originally
introduced as a set of separate error codes from the transport
layer, but having its own set of errors turned out to be very
awkward and they were then converted into a set of #defines that
simply maps them to the global libssh2 error codes instead. Now,
I'l take the next logical step and simply replace the PACKET_*
defines with the actual LIBSSH2_ERROR_* defines. It will increase
readability and decrease confusion.
I also separated packet stuff into its own packet.h header file.
We reserve ^libssh2_ for public symbols and we use _libssh2 as
prefix for internal ones. I fixed the intendation of all these
edits with emacs afterwards, which then changed it slightly more
than just _libssh2_error() expressions but I didn't see any
obvious problems.
When _libssh2_channel_write() is asked to send off 9 bytes, the
code needs to deal with the situation where less than 9 bytes
were sent off and prepare to send the remaining piece at a later
time.
libssh2_error() no longer allocates a string and only accepts a const
error string. I also made a lot of functions use the construct of
return libssh2_error(...) instead of having one call to
libssh2_error() and then a separate return call. In several of those
cases I then also changed the former -1 return code to a more
detailed one - something that I think will not change behaviors
anywhere but it's worth keeping an eye open for any such.
The libssh2 API calls should set the last error code and a message when
returning a failure by calling libssh2_error. This changeset adds these
calls to the libssh2_knownhost_* API as well as libssh2_base64_decode.
This change also makes libssh2_error into a function rather than a macro.
Its implementation is moved to misc.c. This function returns the error
code passed to it allowing callers to return the error value directly
without duplicating the error code.
The libssh2_trace_sethandler() call allows the user to handle the output of libssh2 rather than having it written to stderr. This patch updates libssh2_trace_sethandler() to allow a user-defined void* context value to be passed back to the output handler.
