> -----Original Message-----
> From: curl-library-bounces_at_cool.haxx.se
> [mailto:curl-library-bounces_at_cool.haxx.se] On Behalf Of
> Daniel Stenberg
> Sent: Monday, May 03, 2010 8:04 PM
> To: libcurl development
> Subject: RE: Reflection for Secure IT Server
>
> On Mon, 3 May 2010, Xu, Qiang (FXSGSC) wrote:
>
> > Just tried the latest curl snapshot, with the same result:
>
> > The file sitting in the remote folder is still 16KB, while
> the local
> > file's size is 512KB. :-(
>
> Are those 16KB the first 16KB of the source file or are they
> broken somehow?
>
> I would think you need to instrument how lissh2_sftp_write()
> that libcurl uses acts, and what libcurl then does after the
> working ones etc. Possibly in combination with enabling
> libssh2 debug tracing.

Coz I've had no luck with "libssh2_trace(sshc->sftp_session, ~0)" so far, some other method has been tried:
=====================================================
/* code in curl-7.20.1/src/ssh.c */
ssize_t Curl_sftp_send(struct connectdata *conn, int sockindex,
                       const void *mem, size_t len)
{
  ssize_t nwrite; /* libssh2_sftp_write() used to return size_t in 0.14
                       but is changed to ssize_t in 0.15. These days we don't
                       support libssh2 0.15*/
  (void)sockindex;

  nwrite = libssh2_sftp_write(conn->proto.sshc.sftp_handle, mem, len);

//xq.0
  if (nwrite == LIBSSH2_ERROR_EAGAIN)
          infof(conn->data, "libssh2_sftp_write() returns LIBSSH2_ERROR_EAGAIN\n");
  else
          infof(conn->data, "libssh2_sftp_write() writes [%d] bytes\n", nwrite);
//xq.1

  ssh_block2waitfor(conn, (nwrite == LIBSSH2_ERROR_EAGAIN)?TRUE:FALSE);

  if(nwrite == LIBSSH2_ERROR_EAGAIN)
    return 0;

  return nwrite;
}

/* log for transfer success */
qxu@durian(pts/1):~/opensrc/curl-7.20.1/src[253]$ ./curl -v -k -u <user>:<pass> -T testSmall.pdf sftp://13.121.8.133/Home/Scans/
* About to connect() to 13.198.98.190 port 22 (#0)
* Trying 13.198.98.190... % Total % Received % Xferd Average Speed Time Time Time Current
                                 Dload Upload Total Spent Left Speed
  0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0connected
* Connected to 13.198.98.190 (13.198.98.190) port 22 (#0)
...
* Initialized password authentication
* Authentication complete
* libssh2_sftp_write() returns LIBSSH2_ERROR_EAGAIN
} [data not shown]
* libssh2_sftp_write() writes [16384] bytes
} [data not shown]
...
* libssh2_sftp_write() returns LIBSSH2_ERROR_EAGAIN
} [data not shown]
* libssh2_sftp_write() writes [16384] bytes
} [data not shown]
* libssh2_sftp_write() returns LIBSSH2_ERROR_EAGAIN
} [data not shown]
* libssh2_sftp_write() writes [15436] bytes
} [data not shown]
100 511k 0 0 100 511k 0 1111k --:--:-- --:--:-- --:--:-- 1115k100 511k 0 0 100 511k 0 1111k --:--:-- --:--:-- --:--:-- 1111k*
Connection #0 to host 13.198.98.190 left intact

* Closing connection #0

/* log for transfer failure */
qxu@durian(pts/1):~/opensrc/curl-7.20.1/src[254]$ ./curl -v -k -u <user>:<pass> -T testSmall.pdf sftp://13.121.8.133/Home/Scans/
* About to connect() to 13.121.8.133 port 22 (#0)
* Trying 13.121.8.133... % Total % Received % Xferd Average Speed Time
    Time Time Current
                                 Dload Upload Total Spent Left Speed
  0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0connected
* Connected to 13.121.8.133 (13.121.8.133) port 22 (#0)
* SSH authentication methods available: password
* Initialized password authentication
* Authentication complete
* libssh2_sftp_write() writes [16311] bytes
} [data not shown]
  3 511k 0 0 3 16311 0 1422 0:06:08 0:00:11 0:05:57 1492 3 511k 0 0 3 16311 0 1307 0:06:40 0:00:12 0:06:28 1367*
libssh2_sftp_write() writes [-7] bytes
} [data not shown]
* libssh2_sftp_write() writes [-7] bytes
} [data not shown]
* libssh2_sftp_write() writes [-7] bytes
} [data not shown]
... /* this -7 bytes pattern repeated endlessly */
=====================================================
For the successful case, libssh2_sftp_write() returns LIBSSH2_ERROR_EAGAIN, then writes 16KB (16,384 bytes) to the server. This pattern repeats itself again and again, untill the whole file has been transferred to the destination. For the failure case, libssh2_sftp_write() firstly writes 16311 bytes to the server, then it just returns -7. LIBSSH2_ERROR_EAGAIN never appears, strangely.

How come libssh2_sftp_write() returns -7 rather than -37 (LIBSSH2_ERROR_EAGAIN)? From libssh2.h, it can be seen -7 is LIBSSH2_ERROR_SOCKET_SEND. Is it suggesting the response from the server is not what we expected?

Thanks,
Xu Qiang
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Received on 2010-05-04