diff --git a/conf.c b/conf.c
index d1afea9..8477a6e 100644
--- a/conf.c
+++ b/conf.c
@@ -20,7 +20,6 @@
 #include <sched.h>
 #include <sys/types.h>
 #include <sys/stat.h>
-#include <libgen.h>
 #include <limits.h>
 #include <grp.h>
 #include <pwd.h>
@@ -574,73 +573,6 @@ static int conf_pasta_ns(int *netns_only, char *userns, char *netns,
 	return 0;
 }
 
-/**
- * conf_ns_check() - Check if we can enter configured namespaces
- * @arg:	Execution context
- *
- * Return: 0
- */
-static int conf_ns_check(void *arg)
-{
-	struct ctx *c = (struct ctx *)arg;
-
-	if ((!c->netns_only && setns(c->pasta_userns_fd, CLONE_NEWUSER)) ||
-	    setns(c->pasta_netns_fd, CLONE_NEWNET))
-		c->pasta_userns_fd = c->pasta_netns_fd = -1;
-
-	return 0;
-
-}
-
-/**
- * conf_ns_open() - Open network, user namespaces descriptors from configuration
- * @c:		Execution context
- * @userns:	--userns argument, can be an empty string
- * @netns:	network namespace path
- *
- * Return: 0 on success, negative error code otherwise
- */
-static int conf_ns_open(struct ctx *c, const char *userns, const char *netns)
-{
-	int ufd = -1, nfd = -1;
-
-	nfd = open(netns, O_RDONLY | O_CLOEXEC);
-	if (nfd < 0) {
-		err("Couldn't open network namespace %s", netns);
-		return -ENOENT;
-	}
-
-	if (!c->netns_only && *userns) {
-		ufd = open(userns, O_RDONLY | O_CLOEXEC);
-		if (ufd < 0) {
-			close(nfd);
-			err("Couldn't open user namespace %s", userns);
-			return -ENOENT;
-		}
-	}
-
-	c->pasta_netns_fd = nfd;
-	c->pasta_userns_fd = ufd;
-
-	NS_CALL(conf_ns_check, c);
-
-	if (c->pasta_netns_fd < 0) {
-		err("Couldn't switch to pasta namespaces");
-		return -ENOENT;
-	}
-
-	if (!c->no_netns_quit) {
-		char buf[PATH_MAX];
-
-		strncpy(buf, netns, PATH_MAX);
-		strncpy(c->netns_base, basename(buf), PATH_MAX - 1);
-		strncpy(buf, netns, PATH_MAX);
-		strncpy(c->netns_dir, dirname(buf), PATH_MAX - 1);
-	}
-
-	return 0;
-}
-
 /**
  * conf_ip4() - Verify or detect IPv4 support, get relevant addresses
  * @ifi:	Host interface to attempt (0 to determine one)
@@ -1598,9 +1530,7 @@ void conf(struct ctx *c, int argc, char **argv)
 
 	if (c->mode == MODE_PASTA) {
 		if (*netns) {
-			ret = conf_ns_open(c, userns, netns);
-			if (ret < 0)
-				usage(argv[0]);
+			pasta_open_ns(c, userns, netns);
 		} else {
 			pasta_start_ns(c, argc - optind, argv + optind);
 		}
diff --git a/pasta.c b/pasta.c
index 0bdb655..0fd45e4 100644
--- a/pasta.c
+++ b/pasta.c
@@ -20,6 +20,7 @@
 #include <stdio.h>
 #include <string.h>
 #include <errno.h>
+#include <libgen.h>
 #include <limits.h>
 #include <stdlib.h>
 #include <stdint.h>
@@ -101,6 +102,71 @@ netns:
 	return 0;
 }
 
+/**
+ * ns_check() - Check if we can enter configured namespaces
+ * @arg:	Execution context
+ *
+ * Return: 0
+ */
+static int ns_check(void *arg)
+{
+	struct ctx *c = (struct ctx *)arg;
+
+	if ((!c->netns_only && setns(c->pasta_userns_fd, CLONE_NEWUSER)) ||
+	    setns(c->pasta_netns_fd, CLONE_NEWNET))
+		c->pasta_userns_fd = c->pasta_netns_fd = -1;
+
+	return 0;
+
+}
+
+/**
+ * pasta_open_ns() - Open network, user namespaces descriptors
+ * @c:		Execution context
+ * @userns:	--userns argument, can be an empty string
+ * @netns:	network namespace path
+ *
+ * Return: 0 on success, negative error code otherwise
+ */
+void pasta_open_ns(struct ctx *c, const char *userns, const char *netns)
+{
+	int ufd = -1, nfd = -1;
+
+	nfd = open(netns, O_RDONLY | O_CLOEXEC);
+	if (nfd < 0) {
+		err("Couldn't open network namespace %s", netns);
+		exit(EXIT_FAILURE);
+	}
+
+	if (!c->netns_only && *userns) {
+		ufd = open(userns, O_RDONLY | O_CLOEXEC);
+		if (ufd < 0) {
+			close(nfd);
+			err("Couldn't open user namespace %s", userns);
+			exit(EXIT_FAILURE);
+		}
+	}
+
+	c->pasta_netns_fd = nfd;
+	c->pasta_userns_fd = ufd;
+
+	NS_CALL(ns_check, c);
+
+	if (c->pasta_netns_fd < 0) {
+		err("Couldn't switch to pasta namespaces");
+		exit(EXIT_FAILURE);
+	}
+
+	if (!c->no_netns_quit) {
+		char buf[PATH_MAX] = { 0 };
+
+		strncpy(buf, netns, PATH_MAX - 1);
+		strncpy(c->netns_base, basename(buf), PATH_MAX - 1);
+		strncpy(buf, netns, PATH_MAX - 1);
+		strncpy(c->netns_dir, dirname(buf), PATH_MAX - 1);
+	}
+}
+
 /**
  * struct pasta_setup_ns_arg - Argument for pasta_setup_ns()
  * @c:		Execution context
diff --git a/pasta.h b/pasta.h
index 19b2e54..a1937b2 100644
--- a/pasta.h
+++ b/pasta.h
@@ -6,6 +6,7 @@
 #ifndef PASTA_H
 #define PASTA_H
 
+void pasta_open_ns(struct ctx *c, const char *userns, const char *netns);
 void pasta_start_ns(struct ctx *c, int argc, char *argv[]);
 void pasta_ns_conf(struct ctx *c);
 void pasta_child_handler(int signal);