Fix handling of the no-selectable-fd case.

diff --git a/tests/selpolltest.c b/tests/selpolltest.c
index e3bb67224d6f3077f420c834604038470091d55c..e4e33185456b2aeee6afac91d0fcdea18a9fb58b 100644 (file)
--- a/tests/selpolltest.c
+++ b/tests/selpolltest.c
@@ -156,12 +156,6 @@ main(int argc, char **argv)
 
        if (pcap_setfilter(pd, &fcode) < 0)
                error("%s", pcap_geterr(pd));
-       if (pcap_get_selectable_fd(pd) == -1)
-               error("pcap_get_selectable_fd() fails");
-       if (dononblock) {
-               if (pcap_setnonblock(pd, 1, ebuf) == -1)
-                       error("pcap_setnonblock failed: %s", ebuf);
-       }
        selectable_fd = pcap_get_selectable_fd(pd);
        if (selectable_fd == -1) {
                printf("Listening on %s, using %s, with a timeout\n",
@@ -171,19 +165,34 @@ main(int argc, char **argv)
                        if (doselect || dopoll)
                                error("select()/poll() isn't supported on %s, even with a timeout",
                                    device);
+               /*
+                * As we won't be notified by select() or poll() that
+                * a read can be done, we'll have to periodically try
+                * reading from the device every time the required
+                * timeout expires, and we don't want those attempts
+                * to block if nothing has arrived in that interval,
+                * so we want to force non-blocking mode.
+                */
+               dononblock = 1;
        } else {
                printf("Listening on %s, using %s\n", device, mechanism);
                required_timeout = NULL;
        }
+       if (dononblock) {
+               if (pcap_setnonblock(pd, 1, ebuf) == -1)
+                       error("pcap_setnonblock failed: %s", ebuf);
+       }
        if (doselect) {
                for (;;) {
                        fd_set setread, setexcept;
                        struct timeval seltimeout;
 
                        FD_ZERO(&setread);
-                       FD_SET(selectable_fd, &setread);
-                       FD_ZERO(&setexcept);
-                       FD_SET(selectable_fd, &setexcept);
+                       if (selectable_fd != -1) {
+                               FD_SET(selectable_fd, &setread);
+                               FD_ZERO(&setexcept);
+                               FD_SET(selectable_fd, &setexcept);
+                       }
                        if (dotimeout) {
                                seltimeout.tv_sec = 0;
                                if (required_timeout != NULL &&
@@ -198,7 +207,8 @@ main(int argc, char **argv)
                                status = select(selectable_fd + 1, &setread,
                                    NULL, &setexcept, &seltimeout);
                        } else {
-                               status = select(selectable_fd + 1, &setread,
+                               status = select((selectable_fd == -1) ?
+                                   0 : selectable_fd + 1, &setread,
                                    NULL, &setexcept, NULL);
                        }
                        if (status == -1) {
@@ -209,14 +219,18 @@ main(int argc, char **argv)
                                        printf("Select timed out: ");
                                else
                                        printf("Select returned a descriptor: ");
-                               if (FD_ISSET(selectable_fd, &setread))
-                                       printf("readable, ");
-                               else
-                                       printf("not readable, ");
-                               if (FD_ISSET(selectable_fd, &setexcept))
-                                       printf("exceptional condition\n");
-                               else
-                                       printf("no exceptional condition\n");
+                               if (selectable_fd == -1)
+                                       printf("couldn't do select() on FD\n");
+                               else {
+                                       if (FD_ISSET(selectable_fd, &setread))
+                                               printf("readable, ");
+                                       else
+                                               printf("not readable, ");
+                                       if (FD_ISSET(selectable_fd, &setexcept))
+                                               printf("exceptional condition\n");
+                                       else
+                                               printf("no exceptional condition\n");
+                               }
                                packet_count = 0;
                                status = pcap_dispatch(pd, -1, countme,
                                    (u_char *)&packet_count);
@@ -240,7 +254,7 @@ main(int argc, char **argv)
                                polltimeout = required_timeout->tv_usec/1000;
                        else
                                polltimeout = -1;
-                       status = poll(&fd, 1, polltimeout);
+                       status = poll(&fd, (selectable_fd == -1) ? 0 : 1, polltimeout);
                        if (status == -1) {
                                printf("Poll returns error (%s)\n",
                                    strerror(errno));