[PATCH v2 2/4] dumpcap: allow multiple invocations

[Stephen Hemminger <stephen@networkplumber.org>]

If dumpcap is run twice with each instance pointing a different
interface, it would fail because of overlap in ring a pool names.
Fix by putting process id in the name.

Fixes: cbb44143be74 ("app/dumpcap: add new packet capture application")
Reported-by: Isaac Boukris <iboukris@gmail.com>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 app/dumpcap/main.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/app/dumpcap/main.c b/app/dumpcap/main.c
index 64294bbfb3e6..37754fd06f4f 100644
--- a/app/dumpcap/main.c
+++ b/app/dumpcap/main.c
@@ -44,7 +44,6 @@
 #include <pcap/pcap.h>
 #include <pcap/bpf.h>
 
-#define RING_NAME "capture-ring"
 #define MONITOR_INTERVAL  (500 * 1000)
 #define MBUF_POOL_CACHE_SIZE 32
 #define BURST_SIZE 32
@@ -647,6 +646,7 @@ static void dpdk_init(void)
 static struct rte_ring *create_ring(void)
 {
 	struct rte_ring *ring;
+	char ring_name[RTE_RING_NAMESIZE];
 	size_t size, log2;
 
 	/* Find next power of 2 >= size. */
@@ -660,28 +660,28 @@ static struct rte_ring *create_ring(void)
 		ring_size = size;
 	}
 
-	ring = rte_ring_lookup(RING_NAME);
-	if (ring == NULL) {
-		ring = rte_ring_create(RING_NAME, ring_size,
-					rte_socket_id(), 0);
-		if (ring == NULL)
-			rte_exit(EXIT_FAILURE, "Could not create ring :%s\n",
-				 rte_strerror(rte_errno));
-	}
+	/* Want one ring per invocation of program */
+	snprintf(ring_name, sizeof(ring_name),
+		 "dumpcap-%u", getpid());
+
+	ring = rte_ring_create(ring_name, ring_size,
+			       rte_socket_id(), 0);
+	if (ring == NULL)
+		rte_exit(EXIT_FAILURE, "Could not create ring :%s\n",
+			 rte_strerror(rte_errno));
+
 	return ring;
 }
 
 static struct rte_mempool *create_mempool(void)
 {
 	const struct interface *intf;
-	static const char pool_name[] = "capture_mbufs";
+	char pool_name[RTE_MEMPOOL_NAMESIZE];
 	size_t num_mbufs = 2 * ring_size;
 	struct rte_mempool *mp;
 	uint32_t data_size = 128;
 
-	mp = rte_mempool_lookup(pool_name);
-	if (mp)
-		return mp;
+	snprintf(pool_name, sizeof(pool_name), "capture_%u", getpid());
 
 	/* Common pool so size mbuf for biggest snap length */
 	TAILQ_FOREACH(intf, &interfaces, next) {
@@ -826,7 +826,7 @@ static void enable_pdump(struct rte_ring *r, struct rte_mempool *mp)
 			rte_exit(EXIT_FAILURE,
 				"Packet dump enable on %u:%s failed %s\n",
 				intf->port, intf->name,
-				rte_strerror(-ret));
+				rte_strerror(rte_errno));
 		}
 
 		if (intf->opts.promisc_mode) {
-- 
2.39.2