Changeset 63af502

Timestamp:

09/05/14 16:17:32 (6 years ago)

Author:

Shane Alcock <salcock@…>

Branches:

4.0.1-hotfixes, cachetimestamps, develop, dpdk-ndag, etsilive, libtrace4, master, ndag_format, pfring, rc-4.0.1, rc-4.0.2, rc-4.0.3, rc-4.0.4, ringdecrementfix, ringperformance, ringtimestampfixes

Children:

cf686e1

Parents:

a7c8f4a

Message:

int: and ring: now respect trace_interrupt

Calling trace_interrupt() will now cause the read_packet functions
for these formats to exit, even if there are no packets available to
read.

Previously, the read_packet call would hang until a packet arrived
and then exit, which essentially meant tools like tracesplit would
hang forever if there were no packets.

File:

• lib/format_linux.c (modified) (3 diffs)

lib/format_linux.c

@@ -893 +893 @@
         int snaplen;
         uint32_t flags = 0;
+        fd_set readfds;
+        struct timeval tout;
+        int ret;
         
         if (!packet->buffer || packet->buf_control == TRACE_CTRL_EXTERNAL) {
@@ -928 +931 @@
         iovec.iov_len = snaplen;
 
-        hdr->wirelen = recvmsg(FORMAT(libtrace->format_data)->fd, &msghdr, MSG_TRUNC);
+        /* Use select to allow us to time out occasionally to check if someone
+         * has hit Ctrl-C or otherwise wants us to stop reading and return
+         * so they can exit their program.
+         */
+
+        while (1) {
+                tout.tv_sec = 0;
+                tout.tv_usec = 500000;
+                FD_ZERO(&readfds);
+                FD_SET(FORMAT(libtrace->format_data)->fd, &readfds);
+
+                ret = select(FORMAT(libtrace->format_data)->fd + 1, &readfds,
+                                NULL, NULL, &tout);
+                if (ret < 0 && errno != EINTR) {
+                        trace_set_err(libtrace, errno, "select");
+                        return -1;
+                } else if (ret < 0) {
+                        continue;
+                } 
+                
+                if (FD_ISSET(FORMAT(libtrace->format_data)->fd, &readfds)) {
+                        /* There's something available for us to read */
+                        break;
+                }
+
+                
+                /* If we get here, we timed out -- check if we should halt */
+                if (libtrace_halt)
+                        return 0;
+        }
+
+        hdr->wirelen = recvmsg(FORMAT(libtrace->format_data)->fd, &msghdr, MSG_TRUNC);
 
         if (hdr->wirelen==~0U) {
@@ -1044 +1078 @@
         assert((((unsigned long) header) & (pagesize - 1)) == 0);
 
-        /* TP_STATUS_USER means that we can use the frame.
-         * When a slot does not have this flag set, the frame is not
-         * ready for consumption.
-         */
-        while (!(header->tp_status & TP_STATUS_USER)) {
+        while (1) {
                 pollset.fd = FORMAT(libtrace->format_data)->fd;
                 pollset.events = POLLIN;
                 pollset.revents = 0;
                 /* Wait for more data */
-                ret = poll(&pollset, 1, -1);
+                ret = poll(&pollset, 1, 500);
                 if (ret < 0) {
                         if (errno != EINTR)
                                 trace_set_err(libtrace,errno,"poll()");
                         return -1;
-                }
+                } else if (ret == 0) {
+                        /* Poll timed out - check if we should exit */
+                        if (libtrace_halt)
+                                return 0;
+                        continue;
+                }
+
+                /* TP_STATUS_USER means that we can use the frame.
+                 * When a slot does not have this flag set, the frame is not
+                 * ready for consumption.
+                 */
+                if (header->tp_status & TP_STATUS_USER)
+                        break;
         }