FreeTDS Development Group

["ZIGLIO, Frediano, VF-IT" <Frediano.Ziglio AT vodafone.com>]

> 
> Dear list,
> 
> I use this great library (libtds) to communicate with MSSQL 
> server on an
> embedded system. It's rather important that this system never stops
> sending data for a longer period of time. But as far as I 
> could observe
> this occurs every time the server becomes unreachable. In both the
> stable release and the CVS version a timeout can be set for this case,
> but in the stable version this triggers an assertion and in the CVS
> version as far as I understand the code it leads to an infinite loop.
> For the latter case there is a rather simple fix which makes the
> goodread function abort instead of waiting forever. I only insert data
> into the database but this has worked reliably now for the 
> last 4 days.
> 
> best regards
> Omar Siam
> 

Opss... please ignore my previous mail. len == 0 means select timeout or
connection close (recv returned 0) so IMO the best way is to detect
connection close in side if ((len = select... and close connection
correctly.

Patch follows (already committed)

diff -u -1 -0 -r1.34 net.c
--- src/tds/net.c       7 Oct 2005 15:07:27 -0000       1.34
+++ src/tds/net.c       24 Nov 2005 09:08:16 -0000
@@ -310,20 +310,25 @@
                tv.tv_sec = timeout;

                if ((len = select(tds->s + 1, &rfds, NULL, NULL, timeout
> 0 ? &tv : NULL)) > 0) {
                        len = 0;
                        if (FD_ISSET(tds->s, &rfds)) {
 #ifndef MSG_NOSIGNAL
                                len = READSOCKET(tds->s, buf + got,
buflen);
 #else
                                len = recv(tds->s, buf + got, buflen,
MSG_NOSIGNAL);
 #endif
+                               /* detect connection close */
+                               if (len == 0) {
+                                       tds_close_socket(tds);
+                                       return -1;
+                               }
                        }
                }

                if (len < 0) {
                        switch(sock_errno) {
                        case TDSSOCK_EINTR:
                                tdsdump_log(TDS_DBG_NETWORK, "socket
read interrupted\n");
                        case EAGAIN:
                        case TDSSOCK_EINPROGRESS:
                                break;

freddy77