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c1606da450
The existing sftp async read api has two problems : 1. sftp_async_read() assumes that the value of the third parameter count is same as the number of bytes requested to read in the corresponding call to sftp_async_read_begin(). But the documentation of sftp_async_read() allows the value of count parameter to be more than that requested length. If value of count parameter is more than that requested length then sftp_async_read() updates the file->offset incorrectly which leads to further read/writes occuring from incorrect offsets. The problem here is that sftp_async_read() doesn't know about the number of bytes requested to read specified in the call to sftp_async_read_begin(), and it wrongly assumes the value of its count parameter (which is actually the size of the buffer to store the read data) to be the same as the number of bytes requested to read. 2. sftp_async_read_begin() returns an uint32_t type value type casted to int as a request identifier, whereas sftp_async_read() expects an uint32_t type value as a request identifier. Due to this the user has to typecast the identifier returned by sftp_async_read_begin() from int to uint32_t and then pass it to sftp_async_read(). This type casting is cumbersome for the user and hence the approach is not user-friendly. This commit solves the above two problems by introducing a new sftp aio api. The sftp_aio_begin_*() functions in the api send an i/o request to the sftp server and provide the caller a dynamically allocated structure storing information about the sent request. Information like number of bytes requested for i/o, id of sent request etc is stored in the structure. That structure should be provided to the sftp_aio_wait_*() functions in the api which wait for the response corresponding to the request whose info is stored in the provided structure. The libssh user is supposed to handle that structure through an opaque type sftp_aio. Since the structure stores the number of bytes requested for i/o, sftp_aio_wait_*() knows about the number of bytes requested for i/o (specified in the call to sftp_aio_begin_*()) and hence updates the file->offset correctly solving problem #1 present in the existing async api. Since the structure provided by sftp_aio_begin_*() (containing the request id) is supplied to sftp_aio_wait_*(), no casting of id's needs to be done by the user solving problem #2 of the existing async api. Signed-off-by: Eshan Kelkar <eshankelkar@galorithm.com> Reviewed-by: Sahana Prasad <sahana@redhat.com> Reviewed-by: Jakub Jelen <jjelen@redhat.com>
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The SSH library
Why?
Why not ? :) I've began to work on my own implementation of the ssh protocol because i didn't like the currently public ones. Not any allowed you to import and use the functions as a powerful library, and so i worked on a library-based SSH implementation which was non-existing in the free and open source software world.
How/Who?
If you downloaded this file, you must know what it is : a library for accessing ssh client services through C libraries calls in a simple manner. Everybody can use this software under the terms of the LGPL - see the COPYING file
If you ask yourself how to compile libssh, please read INSTALL before anything.
Where ?
Contributing
Please read the file 'CONTRIBUTING.md' next to this README file. It explains our copyright policy and how you should send patches for upstream inclusion.
Have fun and happy libssh hacking!
The libssh Team