I am trying to write a very small shell client for some automation related
things and am running into problems with libssh2_channel_read. Here are the
two scenarios (application has to be single threaded.):
1. Blocking mode: libssh2_channel_read blocks if there's no data and never
returns. Its impossible to use this function reliably.
2. Non-blocking mode: libssh2_channel_read doesn't block but keeps on
returning -37 (LIBSSH2_ERROR_EAGAIN) and I end up with essentially the same
problem i.e. stuck in an infinite loop. To top it off libssh2_channel_eof
doesn't work and always returns 0.
I don't know what's wrong or what needs to be done but I cannot seem to
find a way through this problem. I have tried libssh2 v 1.3.1 and the
latest one 1.4.1 with the same result. Given below is my readOutput method
which reads the output:
for (;;count++)
{
/* loop until we block */
int rc;
do {
char buffer[1024];
rc = libssh2_channel_read(channel, buffer, sizeof(buffer));
if (rc > 0) {
bytecount += rc;
buffer[rc] = '\0';
fprintf(stderr, "%s", buffer);
count = 0;
}
else {
if (rc != LIBSSH2_ERROR_EAGAIN)
fprintf(stderr, "libssh2_channel_read returned %d\n",
rc);
}
if (libssh2_channel_eof(channel)) {
rc = 0;
break;
}
}
while(rc > 0);
//::Sleep(3);
/* this is due to blocking that would occur otherwise so we loop on
this condition */
if(rc == LIBSSH2_ERROR_EAGAIN)
{
::Sleep(5);
//waitsocket(sock, sshSession);
}
else
break;
}
-- Regards, Zulfiqar Inayat Malik. for (;;count++)
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Received on 2012-04-11