Close the eventfd if we are non-blocking
The eventfd is used to break out of a poll() before it
times out, used by pcap_breakloop(). If we are non-blocking,
then the eventfd is never needed, so we close it. (And
open a new eventfd if we switch to blocking).
(cherry picked from commit 024fd9717d43835f3e08b3146714532768910d3c)
diff --git a/pcap-linux.c b/pcap-linux.c
index 8ceffde..43d2a9f 100644
--- a/pcap-linux.c
+++ b/pcap-linux.c
@@ -842,7 +842,10 @@
handlep->device = NULL;
}
- close(handlep->poll_breakloop_fd);
+ if (handlep->poll_breakloop_fd != -1) {
+ close(handlep->poll_breakloop_fd);
+ handlep->poll_breakloop_fd = -1;
+ }
pcap_cleanup_live_common(handle);
}
@@ -941,7 +944,8 @@
uint64_t value = 1;
/* XXX - what if this fails? */
- (void)write(handlep->poll_breakloop_fd, &value, sizeof(value));
+ if (handlep->poll_breakloop_fd != -1)
+ (void)write(handlep->poll_breakloop_fd, &value, sizeof(value));
}
/*
@@ -3375,7 +3379,23 @@
*/
handlep->timeout = ~handlep->timeout;
}
+ if (handlep->poll_breakloop_fd != -1) {
+ /* Close the eventfd; we do not need it in nonblock mode. */
+ close(handlep->poll_breakloop_fd);
+ handlep->poll_breakloop_fd = -1;
+ }
} else {
+ if (handlep->poll_breakloop_fd == -1) {
+ /* If we did not have an eventfd, open one now that we are blocking. */
+ if ( ( handlep->poll_breakloop_fd = eventfd(0, EFD_NONBLOCK) ) == -1 ) {
+ int save_errno = errno;
+ snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+ "Could not open eventfd: %s",
+ strerror(errno));
+ errno = save_errno;
+ return -1;
+ }
+ }
if (handlep->timeout < 0) {
handlep->timeout = ~handlep->timeout;
}
@@ -3419,10 +3439,24 @@
struct ifreq ifr;
int ret;
struct pollfd pollinfo[2];
+ int numpollinfo;
pollinfo[0].fd = handle->fd;
pollinfo[0].events = POLLIN;
- pollinfo[1].fd = handlep->poll_breakloop_fd;
- pollinfo[1].events = POLLIN;
+ if ( handlep->poll_breakloop_fd == -1 ) {
+ numpollinfo = 1;
+ pollinfo[1].revents = 0;
+ /*
+ * We set pollinfo[1].revents to zero, even though
+ * numpollinfo = 1 meaning that poll() doesn't see
+ * pollinfo[1], so that we do not have to add a
+ * conditional of numpollinfo > 1 below when we
+ * test pollinfo[1].revents.
+ */
+ } else {
+ pollinfo[1].fd = handlep->poll_breakloop_fd;
+ pollinfo[1].events = POLLIN;
+ numpollinfo = 2;
+ }
/*
* Keep polling until we either get some packets to read, see
@@ -3487,7 +3521,7 @@
if (timeout != 0)
timeout = 1;
}
- ret = poll(pollinfo, 2, timeout);
+ ret = poll(pollinfo, numpollinfo, timeout);
if (ret < 0) {
/*
* Error. If it's not EINTR, report it.
diff --git a/testprogs/Makefile.in b/testprogs/Makefile.in
index 0b4e99e..f195693 100644
--- a/testprogs/Makefile.in
+++ b/testprogs/Makefile.in
@@ -85,6 +85,7 @@
findalldevstest-perf.c \
findalldevstest.c \
opentest.c \
+ nonblocktest.c \
reactivatetest.c \
selpolltest.c \
threadsignaltest.c \
@@ -126,6 +127,10 @@
$(CC) $(FULL_CFLAGS) -I. -L. -o opentest $(srcdir)/opentest.c \
../libpcap.a $(LIBS)
+nonblocktest: $(srcdir)/nonblocktest.c ../libpcap.a
+ $(CC) $(FULL_CFLAGS) -I. -L. -o nonblocktest $(srcdir)/nonblocktest.c \
+ ../libpcap.a $(LIBS)
+
reactivatetest: $(srcdir)/reactivatetest.c ../libpcap.a
$(CC) $(FULL_CFLAGS) -I. -L. -o reactivatetest \
$(srcdir)/reactivatetest.c ../libpcap.a $(LIBS)
diff --git a/testprogs/nonblocktest.c b/testprogs/nonblocktest.c
new file mode 100644
index 0000000..72700a3
--- /dev/null
+++ b/testprogs/nonblocktest.c
@@ -0,0 +1,187 @@
+/*
+ * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 2000
+ * The Regents of the University of California. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that: (1) source code distributions
+ * retain the above copyright notice and this paragraph in its entirety, (2)
+ * distributions including binary code include the above copyright notice and
+ * this paragraph in its entirety in the documentation or other materials
+ * provided with the distribution, and (3) all advertising materials mentioning
+ * features or use of this software display the following acknowledgement:
+ * ``This product includes software developed by the University of California,
+ * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
+ * the University nor the names of its contributors may be used to endorse
+ * or promote products derived from this software without specific prior
+ * written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+#include "varattrs.h"
+
+/*
+ * Tests for pcap_set_nonblock / pcap_get_nonblock:
+ * - idempotency
+ * - set/get are symmetric
+ * - get returns the same before/after activate
+ * - pcap_breakloop works after setting nonblock on and then off
+ *
+ * Really this is meant to
+ * be run manually under strace, to check for extra
+ * calls to eventfd or close.
+ */
+#include <pcap.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdarg.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+static pcap_t *pd;
+static char *program_name = "nonblocktest";
+/* Forwards */
+static void PCAP_NORETURN usage(void);
+static void PCAP_NORETURN error(const char *, ...) PCAP_PRINTFLIKE(1, 2);
+static void warning(const char *, ...) PCAP_PRINTFLIKE(1, 2);
+
+/* VARARGS */
+static void
+error(const char *fmt, ...)
+{
+ va_list ap;
+
+ (void)fprintf(stderr, "%s: ", program_name);
+ va_start(ap, fmt);
+ (void)vfprintf(stderr, fmt, ap);
+ va_end(ap);
+ if (*fmt) {
+ fmt += strlen(fmt);
+ if (fmt[-1] != '\n')
+ (void)fputc('\n', stderr);
+ }
+ exit(1);
+ /* NOTREACHED */
+}
+
+/* VARARGS */
+static void
+warning(const char *fmt, ...)
+{
+ va_list ap;
+
+ (void)fprintf(stderr, "%s: WARNING: ", program_name);
+ va_start(ap, fmt);
+ (void)vfprintf(stderr, fmt, ap);
+ va_end(ap);
+ if (*fmt) {
+ fmt += strlen(fmt);
+ if (fmt[-1] != '\n')
+ (void)fputc('\n', stderr);
+ }
+}
+
+static void
+usage(void)
+{
+ (void)fprintf(stderr, "Usage: %s [ -i interface ]\n",
+ program_name);
+ exit(1);
+}
+
+static void
+breakme(u_char *user _U_, const struct pcap_pkthdr *h _U_, const u_char *sp _U_)
+{
+ warning("using pcap_breakloop()");
+ pcap_breakloop(pd);
+}
+
+int
+main(int argc, char **argv)
+{
+ int status, op, i, ret;
+ char *device;
+ pcap_if_t *devlist;
+ char ebuf[PCAP_ERRBUF_SIZE];
+
+ device = NULL;
+ while ((op = getopt(argc, argv, "i:sptnq")) != -1) {
+ switch (op) {
+
+ case 'i':
+ device = optarg;
+ break;
+
+ default:
+ usage();
+ /* NOTREACHED */
+ }
+ }
+ if (device == NULL) {
+ if (pcap_findalldevs(&devlist, ebuf) == -1)
+ error("%s", ebuf);
+ if (devlist == NULL)
+ error("no interfaces available for capture");
+ device = strdup(devlist->name);
+ warning("listening on %s", device);
+ pcap_freealldevs(devlist);
+ }
+ *ebuf = '\0';
+ pd = pcap_create(device, ebuf);
+ if (pd == NULL)
+ error("%s", ebuf);
+ else if (*ebuf)
+ warning("%s", ebuf);
+ /* set nonblock before activate */
+ if (pcap_setnonblock(pd, 1, ebuf) < 0)
+ error("pcap_setnonblock failed: %s", ebuf);
+ /* getnonblock just returns "not activated yet" */
+ ret = pcap_getnonblock(pd, ebuf);
+ if (ret != PCAP_ERROR_NOT_ACTIVATED)
+ error("pcap_getnonblock unexpectedly succeeded");
+ if ((status = pcap_activate(pd)) < 0)
+ error("pcap_activate failed");
+ ret = pcap_getnonblock(pd, ebuf);
+ if (ret != 1)
+ error( "pcap_getnonblock did not return nonblocking" );
+
+ /* Set nonblock multiple times, ensure with strace that it's a noop */
+ for (i=0; i<10; i++) {
+ if (pcap_setnonblock(pd, 1, ebuf) < 0)
+ error("pcap_setnonblock failed: %s", ebuf);
+ ret = pcap_getnonblock(pd, ebuf);
+ if (ret != 1)
+ error( "pcap_getnonblock did not return nonblocking" );
+ }
+ /* Set block multiple times, ensure with strace that it's a noop */
+ for (i=0; i<10; i++) {
+ if (pcap_setnonblock(pd, 0, ebuf) < 0)
+ error("pcap_setnonblock failed: %s", ebuf);
+ ret = pcap_getnonblock(pd, ebuf);
+ if (ret != 0)
+ error( "pcap_getnonblock did not return blocking" );
+ }
+
+ /* Now pcap_loop forever, with a callback that
+ * uses pcap_breakloop to get out of forever */
+ pcap_loop(pd, -1, breakme, NULL);
+
+ /* Now test that pcap_setnonblock fails if we can't open the
+ * eventfd. */
+ if (pcap_setnonblock(pd, 1, ebuf) < 0)
+ error("pcap_setnonblock failed: %s", ebuf);
+ while (1) {
+ ret = open("/dev/null", O_RDONLY);
+ if (ret < 0)
+ break;
+ }
+ ret = pcap_setnonblock(pd, 0, ebuf);
+ if (ret == 0)
+ error("pcap_setnonblock succeeded even though file table is full");
+ else
+ warning("pcap_setnonblock failed as expected: %s", ebuf);
+}
