FW: Infinite Blocking! Need Help

["Preston, Robert W CIV SPAWARSYSCEN-PACIFIC, 56430" <robert.w.preston@xxxxxxxx>]

Hi all,

I could really use some help with the following issue. I'm using libssh to transfer files via sftp and everything is working well except for when I test it with my server down. I would expect the for the polling to timeout and return a failure so that the program log the failed connection. Instead the program polls for ever on the line select call in the following function:                                                 static int bsd_poll(ssh_pollfd_t *fds, nfds_t nfds, int timeout) {
fd_set readfds, writefds, exceptfds;
struct timeval tv, *ptv;
socket_t max_fd;
int rc;
nfds_t i;
if (fds == NULL) {
errno = EFAULT;
return -1;
}
FD_ZERO (&readfds);
FD_ZERO (&writefds);
FD_ZERO (&exceptfds);
/* compute fd_sets and find largest descriptor */
for (rc = -1, max_fd = 0, i = 0; i < nfds; i++) {
if (fds[i].fd == SSH_INVALID_SOCKET) {
continue;
}
#ifndef _WIN32
if (fds[i].fd >= FD_SETSIZE) {
rc = -1;
break;
}
#endif
if (fds[i].events & (POLLIN | POLLRDNORM)) {
FD_SET (fds[i].fd, &readfds);
}
if (fds[i].events & (POLLOUT | POLLWRNORM | POLLWRBAND)) {
FD_SET (fds[i].fd, &writefds);
}
if (fds[i].events & (POLLPRI | POLLRDBAND)) {
FD_SET (fds[i].fd, &exceptfds);
}
if (fds[i].fd > max_fd &&
(fds[i].events & (POLLIN | POLLOUT | POLLPRI |
POLLRDNORM | POLLRDBAND |
POLLWRNORM | POLLWRBAND))) {
max_fd = fds[i].fd;
rc = 0;
}
}
if (max_fd == SSH_INVALID_SOCKET || rc == -1) {
errno = EINVAL;
return -1;
}
if (timeout < 0) {
ptv = NULL;
} else {
ptv = &tv;
if (timeout == 0) {
tv.tv_sec = 0;
tv.tv_usec = 0;
} else {
tv.tv_sec = timeout / 1000;
tv.tv_usec = (timeout % 1000) * 1000;
}
}
rc = select (max_fd + 1, &readfds, &writefds, &exceptfds, ptv);
if (rc < 0) {
return -1;
}
for (rc = 0, i = 0; i < nfds; i++)
if (fds[i].fd >= 0) {
fds[i].revents = 0;
if (FD_ISSET(fds[i].fd, &readfds)) {
int save_errno = errno;
char data[64] = {0};
int ret;
/* support for POLLHUP */
ret = recv(fds[i].fd, data, 64, MSG_PEEK);
#ifdef _WIN32
if ((ret == -1) &&
(errno == WSAESHUTDOWN || errno == WSAECONNRESET ||
errno == WSAECONNABORTED || errno == WSAENETRESET)) {
#else
if ((ret == -1) &&
(errno == ESHUTDOWN || errno == ECONNRESET ||
errno == ECONNABORTED || errno == ENETRESET)) {
#endif
fds[i].revents |= POLLHUP;
} else {
fds[i].revents |= fds[i].events & (POLLIN | POLLRDNORM);
}
errno = save_errno;
}
if (FD_ISSET(fds[i].fd, &writefds)) {
fds[i].revents |= fds[i].events & (POLLOUT | POLLWRNORM | POLLWRBAND);
}
if (FD_ISSET(fds[i].fd, &exceptfds)) {
fds[i].revents |= fds[i].events & (POLLPRI | POLLRDBAND);
}
if (fds[i].revents & ~POLLHUP) {
rc++;
}
} else {
fds[i].revents = POLLNVAL;
}
return rc;
}


 I am using a branch I found at the following location https://red.libssh.org/issues/42



Any ideas on a work around for this issue? Any help would be much appreciated.

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