mkdir -p /proc /sys on container startup

src/lxc/conf.c

@@ -3278,6 +3278,24 @@ int lxc_setup(struct lxc_handler *handler)
 	if (ret < 0)
 		return log_error(-1, "Failed to setup rootfs");
 
+	/* Create mountpoints for /proc and /sys. */
+	char path[PATH_MAX];
+	char *rootfs_path = lxc_conf->rootfs.path ? lxc_conf->rootfs.mount : "";
+
+	ret = snprintf(path, sizeof(path), "%s/proc", rootfs_path);
+	if (ret < 0 || (size_t)ret >= sizeof(path))
+		return log_error(-1, "Path to /proc too long");
+	ret = mkdir(path, 0755);
+	if (ret < 0 && errno != EEXIST)
+		return log_error_errno(-1, errno, "Failed to create \"/proc\" directory");
+
+	ret = snprintf(path, sizeof(path), "%s/sys", rootfs_path);
+	if (ret < 0 || (size_t)ret >= sizeof(path))
+		return log_error(-1, "Path to /sys too long");
+	ret = mkdir(path, 0755);
+	if (ret < 0 && errno != EEXIST)
+		return log_error_errno(-1, errno, "Failed to create \"/sys\" directory");
+
 	if (handler->nsfd[LXC_NS_UTS] == -EBADF) {
 		ret = setup_utsname(lxc_conf->utsname);
 		if (ret < 0)
@@ -3344,7 +3362,6 @@ int lxc_setup(struct lxc_handler *handler)
 	if (lxc_conf->is_execute) {
 		if (execveat_supported()) {
 			int fd;
-			char path[PATH_MAX];
 
 			ret = snprintf(path, PATH_MAX, SBINDIR "/init.lxc.static");
 			if (ret < 0 || ret >= PATH_MAX)

src/tests/Makefile.am

@@ -620,6 +620,7 @@ bin_SCRIPTS += lxc-test-automount \
 	       lxc-test-exit-code \
 	       lxc-test-no-new-privs \
 	       lxc-test-rootfs \
+	       lxc-test-procsys \
 	       lxc-test-usernsexec
 
 if DISTRO_UBUNTU
@@ -658,6 +659,7 @@ EXTRA_DIST = basic.c \
 	     lxc-test-lxc-attach \
 	     lxc-test-automount \
 	     lxc-test-rootfs \
+	     lxc-test-procsys \
 	     lxc-test-autostart \
 	     lxc-test-apparmor-mount \
 	     lxc-test-apparmor-generated \

src/tests/lxc-test-procsys

+#!/bin/bash
+
+# lxc: linux Container library
+
+# Authors:
+# Motiejus Jakštys <motiejus@jakstys.lt>
+#
+# Ensure that when /proc and/or /sys do not exist in the container,
+# it is started successfully anyway.
+
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+
+set -ex
+FAIL() {
+	echo -n "Failed " >&2
+	echo "$*" >&2
+	lxc-destroy -n lxc-test-procsys -f
+	exit 1
+}
+
+lxc-destroy -n lxc-test-procsys -f || :
+lxc-create -t busybox -n lxc-test-procsys
+rmdir /var/lib/lxc/lxc-test-procsys/rootfs/{proc,sys}
+
+lxc-start -n lxc-test-procsys
+lxc-wait -n lxc-test-procsys -s RUNNING || FAIL "waiting for busybox container to run"
+
+lxc-attach -n lxc-test-procsys -- sh -c 'test -f /proc/version' || FAIL "/proc/version not found"
+lxc-attach -n lxc-test-procsys -- sh -c 'test -d /sys/fs' || FAIL "/sys/fs not found"
+
+lxc-destroy -n lxc-test-procsys -f
+exit 0