+ )
+ return false;
+
+ return true;
+}
+
+/* Wait for a single descriptor to become available, timing out after
+ MAXTIME seconds. Returns 1 if FD is available, 0 for timeout and
+ -1 for error. The argument WAIT_FOR can be a combination of
+ WAIT_FOR_READ and WAIT_FOR_WRITE.
+
+ This is a mere convenience wrapper around the select call, and
+ should be taken as such (for example, it doesn't implement Wget's
+ 0-timeout-means-no-timeout semantics.) */
+
+int
+select_fd (int fd, double maxtime, int wait_for)
+{
+ fd_set fdset;
+ fd_set *rd = NULL, *wr = NULL;
+ struct timeval tmout;
+ int result;
+
+ FD_ZERO (&fdset);
+ FD_SET (fd, &fdset);
+ if (wait_for & WAIT_FOR_READ)
+ rd = &fdset;
+ if (wait_for & WAIT_FOR_WRITE)
+ wr = &fdset;
+
+ tmout.tv_sec = (long) maxtime;
+ tmout.tv_usec = 1000000 * (maxtime - (long) maxtime);
+
+ do
+ result = select (fd + 1, rd, wr, NULL, &tmout);
+ while (result < 0 && errno == EINTR);
+
+ return result;
+}
+
+/* Return true iff the connection to the remote site established
+ through SOCK is still open.
+
+ Specifically, this function returns true if SOCK is not ready for
+ reading. This is because, when the connection closes, the socket
+ is ready for reading because EOF is about to be delivered. A side
+ effect of this method is that sockets that have pending data are
+ considered non-open. This is actually a good thing for callers of
+ this function, where such pending data can only be unwanted
+ leftover from a previous request. */
+
+bool
+test_socket_open (int sock)
+{
+ fd_set check_set;
+ struct timeval to;
+
+ /* Check if we still have a valid (non-EOF) connection. From Andrew
+ * Maholski's code in the Unix Socket FAQ. */
+
+ FD_ZERO (&check_set);
+ FD_SET (sock, &check_set);
+
+ /* Wait one microsecond */
+ to.tv_sec = 0;
+ to.tv_usec = 1;
+
+ if (select (sock + 1, &check_set, NULL, NULL, &to) == 0)
+ /* We got a timeout, it means we're still connected. */
+ return true;
+ else
+ /* Read now would not wait, it means we have either pending data
+ or EOF/error. */
+ return false;
+}
+\f
+/* Basic socket operations, mostly EINTR wrappers. */
projects / wget / blobdiff