X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=libtracing%2Frelay.c;h=a8775ec77d2554e30bee693a1c6a102c49ec91fd;hb=3847c3bab100bfb6b01b5654c2429a5d0d162ff5;hp=ad22727a5f7102e731ed7cda741f00f847fa5d66;hpb=98963de4a2dfae12d8aafa0f9a6d97cf4a44e12d;p=ust.git

diff --git a/libtracing/relay.c b/libtracing/relay.c
index ad22727..a8775ec 100644
--- a/libtracing/relay.c
+++ b/libtracing/relay.c
@@ -22,8 +22,10 @@
 //ust// #include <linux/cpu.h>
 //ust// #include <linux/splice.h>
 //ust// #include <linux/bitops.h>
-#include <sys/mman.h>
 #include "kernelcompat.h"
+#include <sys/mman.h>
+#include <sys/ipc.h>
+#include <sys/shm.h>
 #include "list.h"
 #include "relay.h"
 #include "channels.h"
@@ -93,21 +95,44 @@ static int relay_alloc_buf(struct rchan_buf *buf, size_t *size)
 	unsigned int n_pages;
 	struct buf_page *buf_page, *n;
 
-	void *result;
+	void *ptr;
+	int result;
 
 	*size = PAGE_ALIGN(*size);
 
-	/* Maybe do read-ahead */
-	result = mmap(NULL, *size, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
-	if(result == MAP_FAILED) {
-		PERROR("mmap");
+	result = buf->shmid = shmget(getpid(), *size, IPC_CREAT | IPC_EXCL | 0700);
+	if(buf->shmid == -1) {
+		PERROR("shmget");
+		return -1;
+	}
+
+	ptr = shmat(buf->shmid, NULL, 0);
+	if(ptr == (void *) -1) {
+		perror("shmat");
+		goto destroy_shmem;
+	}
+
+	/* Already mark the shared memory for destruction. This will occur only
+         * when all users have detached.
+	 */
+	result = shmctl(buf->shmid, IPC_RMID, NULL);
+	if(result == -1) {
+		perror("shmctl");
 		return -1;
 	}
 
-	buf->buf_data = result;
+	buf->buf_data = ptr;
 	buf->buf_size = *size;
 
 	return 0;
+
+	destroy_shmem:
+	result = shmctl(buf->shmid, IPC_RMID, NULL);
+	if(result == -1) {
+		perror("shmctl");
+	}
+
+	return -1;
 }
 
 /**
@@ -2344,9 +2369,14 @@ static struct ltt_transport ust_relay_transport = {
 //ust// 	return 0;
 //ust// }
 
-void init_ustrelay_transport(void)
+static char initialized = 0;
+
+void __attribute__((constructor)) init_ustrelay_transport(void)
 {
-	ltt_transport_register(&ust_relay_transport);
+	if(!initialized) {
+		ltt_transport_register(&ust_relay_transport);
+		initialized = 1;
+	}
 }
 
 static void __exit ltt_relay_exit(void)