diff --git a/include/villas/nodes/shmem.h b/include/villas/nodes/shmem.h
index 10dfeae2f..5bf02ec96 100644
--- a/include/villas/nodes/shmem.h
+++ b/include/villas/nodes/shmem.h
@@ -16,7 +16,6 @@ struct shmem {
 	int cond_out; /**< Whether to use a pthread_cond_t to signal if new samples are written to outqueue. */
 	int cond_in; /**< Whether to use a pthread_cond_t to signal if new samples are written to inqueue. */
 
-	size_t len; /**< Overall size of shared memory object. */
 	struct memtype *manager; /**< Manager for the shared memory region. */
 	int fd; /**< Handle as returned by shm_open().*/
 	void *base; /**< Pointer to the shared memory region. */
diff --git a/include/villas/shmem.h b/include/villas/shmem.h
index 442d05174..543936240 100644
--- a/include/villas/shmem.h
+++ b/include/villas/shmem.h
@@ -11,13 +11,20 @@ union shmem_queue {
 	struct queue_signalled qs;
 };
 
-/** The structure that actually resides in the shared memory. TODO better name?*/
+/** The structure that actually resides in the shared memory. */
 struct shmem_shared {
+	size_t len; /**< Total size of the shared memory region.*/
 	union shmem_queue in; /**< Queue for samples passed from external program to node.*/
+	int cond_in; /**< Whether to use a pthread_cond_t to signal if new samples are written to inqueue. */
 	union shmem_queue out; /**< Queue for samples passed from node to external program.*/
+	int cond_out; /**< Whether to use a pthread_cond_t to signal if new samples are written to outqueue. */
 	struct pool pool; /**< Pool for the samples in the queues. */
 };
 
-struct shmem_shared * shmem_int_open(const char* name, size_t len);
+struct shmem_shared * shmem_shared_open(const char* name);
+
+int shmem_shared_read(struct shmem_shared *shm, struct sample *smps[], unsigned cnt);
+
+int shmem_shared_write(struct shmem_shared *shm, struct sample *smps[], unsigned cnt);
 
 size_t shmem_total_size(int insize, int outsize, int sample_size);
diff --git a/lib/nodes/shmem.c b/lib/nodes/shmem.c
index e1bdc6181..69a1ec689 100644
--- a/lib/nodes/shmem.c
+++ b/lib/nodes/shmem.c
@@ -40,20 +40,22 @@ int shmem_open(struct node *n) {
 		serror("Opening shared memory object failed");
 
 	shm->fd = r;
-	shm->len = shmem_total_size(shm->insize, shm->outsize, shm->sample_size);
-	if (ftruncate(shm->fd, shm->len) < 0)
+	size_t len = shmem_total_size(shm->insize, shm->outsize, shm->sample_size);
+	if (ftruncate(shm->fd, len) < 0)
 		serror("Setting size of shared memory object failed");
-	/* TODO: we could use huge pages here as well */
-	shm->base = mmap(NULL, shm->len, PROT_READ|PROT_WRITE, MAP_SHARED, shm->fd, 0);
+	shm->base = mmap(NULL, len, PROT_READ|PROT_WRITE, MAP_SHARED, shm->fd, 0);
 
 	if (shm->base == MAP_FAILED)
 		serror("Mapping shared memory failed");
 
-	shm->manager = memtype_managed_init(shm->base, shm->len);
+	shm->manager = memtype_managed_init(shm->base, len);
 	shm->shared = memory_alloc(shm->manager, sizeof(struct shmem_shared));
 	if (!shm->shared)
 		error("Shm shared struct allocation failed (not enough memory?)");
 	memset(shm->shared, 0, sizeof(struct shmem_shared));
+	shm->shared->len = len;
+	shm->shared->cond_in = shm->cond_in;
+	shm->shared->cond_out = shm->cond_out;
 	if (shm->cond_in) {
 		if (queue_signalled_init(&shm->shared->in.qs, shm->insize, shm->manager) < 0)
 			error("Shm queue allocation failed (not enough memory?)");
@@ -76,6 +78,7 @@ int shmem_open(struct node *n) {
 
 int shmem_close(struct node *n) {
 	struct shmem* shm = n->_vd;
+	size_t len = shm->shared->len;
 	if (shm->cond_in)
 		queue_signalled_destroy(&shm->shared->in.qs);
 	else
@@ -85,7 +88,7 @@ int shmem_close(struct node *n) {
 	else
 		queue_destroy(&shm->shared->out.q);
 	pool_destroy(&shm->shared->pool);
-	int r = munmap(shm->base, shm->len);
+	int r = munmap(shm->base, len);
 	if (r != 0)
 		return r;
 	return shm_unlink(shm->name);
diff --git a/lib/shmem.c b/lib/shmem.c
index 89d4bc3d1..401405e53 100644
--- a/lib/shmem.c
+++ b/lib/shmem.c
@@ -24,16 +24,42 @@ size_t shmem_total_size(int insize, int outsize, int sample_size)
 		+ 1024;
 }
 
-struct shmem_shared* shmem_int_open(const char *name, size_t len)
+struct shmem_shared* shmem_shared_open(const char *name)
 {
 	int fd = shm_open(name, O_RDWR, 0);
 	if (fd < 0)
 		return NULL;
+	/* Only map the first part (shmem_shared) first, read the correct length,
+	 * the map it with this length. */
+	size_t len = sizeof(struct memtype) + sizeof(struct memblock) + sizeof(struct shmem_shared);
 	void *base = mmap(NULL, len, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
 	if (base == MAP_FAILED)
 		return NULL;
 	/* This relies on the behaviour of the node and the allocator; it assumes
 	 * that memtype_managed is used and the shmem_shared is the first allocated object */
 	char *cptr = (char *) base + sizeof(struct memtype) + sizeof(struct memblock);
+	struct shmem_shared *shm = (struct shmem_shared *) cptr;
+	size_t newlen = shm->len;
+	if (munmap(base, len))
+		return NULL;
+	base = mmap(NULL, newlen, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
+	if (base == MAP_FAILED)
+		return NULL;
+	/* Adress might have moved */
+	cptr = (char *) base + sizeof(struct memtype) + sizeof(struct memblock);
 	return (struct shmem_shared *) cptr;
 }
+
+int shmem_shared_read(struct shmem_shared *shm, struct sample *smps[], unsigned cnt) {
+	if (shm->cond_out)
+		return queue_signalled_pull_many(&shm->out.qs, (void **) smps, cnt);
+	else
+		return queue_pull_many(&shm->out.q, (void **) smps, cnt);
+}
+
+int shmem_shared_write(struct shmem_shared *shm, struct sample *smps[], unsigned cnt) {
+	if (shm->cond_in)
+		return queue_signalled_push_many(&shm->in.qs, (void **) smps, cnt);
+	else
+		return queue_pull_many(&shm->in.q, (void **) smps, cnt);
+}
diff --git a/src/shmem.c b/src/shmem.c
index dc9e7fb71..1a0057ab7 100644
--- a/src/shmem.c
+++ b/src/shmem.c
@@ -40,19 +40,15 @@ int main(int argc, char* argv[])
 		error("Node '%s' does not exist!", argv[2]);
 
 	struct shmem* shm = node->_vd;
-	size_t len = shmem_total_size(shm->insize, shm->outsize, shm->sample_size);
-	struct shmem_shared *shmem = shmem_int_open(shm->name, len);
-	if (!shmem)
+	struct shmem_shared *shared = shmem_shared_open(shm->name);
+	if (!shared)
 		serror("Failed to open shmem interface");
 
 	struct sample *insmps[node->vectorize], *outsmps[node->vectorize];
 	while (1) {
 		int r, w;
-		if (shm->cond_out)
-			r = queue_signalled_pull_many(&shmem->out.qs, (void **) insmps, node->vectorize);
-		else
-			r = queue_pull_many(&shmem->out.q, (void **) insmps, node->vectorize);
-		int avail = sample_alloc(&shmem->pool, outsmps, r);
+		r = shmem_shared_read(shared, insmps, node->vectorize);
+		int avail = sample_alloc(&shared->pool, outsmps, r);
 		if (avail < r)
 			warn("pool underrun (%d/%d)\n", avail, r);
 		for (int i = 0; i < r; i++)
@@ -66,10 +62,7 @@ int main(int argc, char* argv[])
 		}
 		for (int i = 0; i < r; i++)
 			sample_put(insmps[i]);
-		if (shm->cond_in)
-			w = queue_signalled_push_many(&shmem->in.qs, (void **) outsmps, avail);
-		else
-			w = queue_push_many(&shmem->in.q, (void **) outsmps, avail);
+		w = shmem_shared_write(shared, outsmps, avail);
 		if (w < avail)
 			warn("short write (%d/%d)\n", w, r);
 	}