nspawn: split out cgroup related calls into nspawn-cgroup.[ch]

3 files changed, 200 insertions, 140 deletions

diff --git a/src/nspawn/nspawn-cgroup.c b/src/nspawn/nspawn-cgroup.c
new file mode 100644
index 0000000000..cfb4827de5
--- /dev/null
+++ b/src/nspawn/nspawn-cgroup.c
@@ -0,0 +1,163 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2015 Lennart Poettering
+
+  systemd 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.
+
+  systemd 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 systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <sys/mount.h>
+
+#include "util.h"
+#include "strv.h"
+#include "mkdir.h"
+#include "fileio.h"
+#include "cgroup-util.h"
+
+#include "nspawn.h"
+#include "nspawn-cgroup.h"
+
+int chown_cgroup(pid_t pid, uid_t uid_shift) {
+        _cleanup_free_ char *path = NULL, *fs = NULL;
+        _cleanup_close_ int fd = -1;
+        const char *fn;
+        int r;
+
+        r = cg_pid_get_path(NULL, pid, &path);
+        if (r < 0)
+                return log_error_errno(r, "Failed to get container cgroup path: %m");
+
+        r = cg_get_path(SYSTEMD_CGROUP_CONTROLLER, path, NULL, &fs);
+        if (r < 0)
+                return log_error_errno(r, "Failed to get file system path for container cgroup: %m");
+
+        fd = open(fs, O_RDONLY|O_CLOEXEC|O_DIRECTORY);
+        if (fd < 0)
+                return log_error_errno(errno, "Failed to open %s: %m", fs);
+
+        FOREACH_STRING(fn,
+                       ".",
+                       "tasks",
+                       "notify_on_release",
+                       "cgroup.procs",
+                       "cgroup.clone_children",
+                       "cgroup.controllers",
+                       "cgroup.subtree_control",
+                       "cgroup.populated")
+                if (fchownat(fd, fn, uid_shift, uid_shift, 0) < 0)
+                        log_full_errno(errno == ENOENT ? LOG_DEBUG :  LOG_WARNING, errno,
+                                       "Failed to chown() cgroup file %s, ignoring: %m", fn);
+
+        return 0;
+}
+
+int sync_cgroup(pid_t pid, bool unified_requested) {
+        _cleanup_free_ char *cgroup = NULL;
+        char tree[] = "/tmp/unifiedXXXXXX", pid_string[DECIMAL_STR_MAX(pid) + 1];
+        bool undo_mount = false;
+        const char *fn;
+        int unified, r;
+
+        unified = cg_unified();
+        if (unified < 0)
+                return log_error_errno(unified, "Failed to determine whether the unified hierachy is used: %m");
+
+        if ((unified > 0) == unified_requested)
+                return 0;
+
+        /* When the host uses the legacy cgroup setup, but the
+         * container shall use the unified hierarchy, let's make sure
+         * we copy the path from the name=systemd hierarchy into the
+         * unified hierarchy. Similar for the reverse situation. */
+
+        r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, pid, &cgroup);
+        if (r < 0)
+                return log_error_errno(r, "Failed to get control group of " PID_FMT ": %m", pid);
+
+        /* In order to access the unified hierarchy we need to mount it */
+        if (!mkdtemp(tree))
+                return log_error_errno(errno, "Failed to generate temporary mount point for unified hierarchy: %m");
+
+        if (unified)
+                r = mount("cgroup", tree, "cgroup", MS_NOSUID|MS_NOEXEC|MS_NODEV, "none,name=systemd,xattr");
+        else
+                r = mount("cgroup", tree, "cgroup", MS_NOSUID|MS_NOEXEC|MS_NODEV, "__DEVEL__sane_behavior");
+        if (r < 0) {
+                r = log_error_errno(errno, "Failed to mount unified hierarchy: %m");
+                goto finish;
+        }
+
+        undo_mount = true;
+
+        fn = strjoina(tree, cgroup, "/cgroup.procs");
+        (void) mkdir_parents(fn, 0755);
+
+        sprintf(pid_string, PID_FMT, pid);
+        r = write_string_file(fn, pid_string, 0);
+        if (r < 0)
+                log_error_errno(r, "Failed to move process: %m");
+
+finish:
+        if (undo_mount)
+                (void) umount(tree);
+
+        (void) rmdir(tree);
+        return r;
+}
+
+int create_subcgroup(pid_t pid, bool unified_requested) {
+        _cleanup_free_ char *cgroup = NULL;
+        const char *child;
+        int unified, r;
+        CGroupMask supported;
+
+        /* In the unified hierarchy inner nodes may only only contain
+         * subgroups, but not processes. Hence, if we running in the
+         * unified hierarchy and the container does the same, and we
+         * did not create a scope unit for the container move us and
+         * the container into two separate subcgroups. */
+
+        if (!unified_requested)
+                return 0;
+
+        unified = cg_unified();
+        if (unified < 0)
+                return log_error_errno(unified, "Failed to determine whether the unified hierachy is used: %m");
+        if (unified == 0)
+                return 0;
+
+        r = cg_mask_supported(&supported);
+        if (r < 0)
+                return log_error_errno(r, "Failed to determine supported controllers: %m");
+
+        r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, 0, &cgroup);
+        if (r < 0)
+                return log_error_errno(r, "Failed to get our control group: %m");
+
+        child = strjoina(cgroup, "/payload");
+        r = cg_create_and_attach(SYSTEMD_CGROUP_CONTROLLER, child, pid);
+        if (r < 0)
+                return log_error_errno(r, "Failed to create %s subcgroup: %m", child);
+
+        child = strjoina(cgroup, "/supervisor");
+        r = cg_create_and_attach(SYSTEMD_CGROUP_CONTROLLER, child, 0);
+        if (r < 0)
+                return log_error_errno(r, "Failed to create %s subcgroup: %m", child);
+
+        /* Try to enable as many controllers as possible for the new payload. */
+        (void) cg_enable_everywhere(supported, supported, cgroup);
+        return 0;
+}
diff --git a/src/nspawn/nspawn-cgroup.h b/src/nspawn/nspawn-cgroup.h
new file mode 100644
index 0000000000..985fdfaad5
--- /dev/null
+++ b/src/nspawn/nspawn-cgroup.h
@@ -0,0 +1,29 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#pragma once
+
+/***
+  This file is part of systemd.
+
+  Copyright 2015 Lennart Poettering
+
+  systemd 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.
+
+  systemd 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 systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <sys/types.h>
+#include <stdbool.h>
+
+int chown_cgroup(pid_t pid, uid_t uid_shift);
+int sync_cgroup(pid_t pid, bool unified_requested);
+int create_subcgroup(pid_t pid, bool unified_requested);
diff --git a/src/nspawn/nspawn.c b/src/nspawn/nspawn.c
index 7550ca057b..c106b58859 100644
--- a/src/nspawn/nspawn.c
+++ b/src/nspawn/nspawn.c
@@ -101,6 +101,7 @@
 #include "nspawn-mount.h"
 #include "nspawn-network.h"
 #include "nspawn-expose-ports.h"
+#include "nspawn-cgroup.h"
 
 typedef enum ContainerStatus {
         CONTAINER_TERMINATED,
@@ -3292,141 +3293,6 @@ static int setup_uid_map(pid_t pid) {
         return 0;
 }
 
-static int chown_cgroup(pid_t pid) {
-        _cleanup_free_ char *path = NULL, *fs = NULL;
-        _cleanup_close_ int fd = -1;
-        const char *fn;
-        int r;
-
-        r = cg_pid_get_path(NULL, pid, &path);
-        if (r < 0)
-                return log_error_errno(r, "Failed to get container cgroup path: %m");
-
-        r = cg_get_path(SYSTEMD_CGROUP_CONTROLLER, path, NULL, &fs);
-        if (r < 0)
-                return log_error_errno(r, "Failed to get file system path for container cgroup: %m");
-
-        fd = open(fs, O_RDONLY|O_CLOEXEC|O_DIRECTORY);
-        if (fd < 0)
-                return log_error_errno(errno, "Failed to open %s: %m", fs);
-
-        FOREACH_STRING(fn,
-                       ".",
-                       "tasks",
-                       "notify_on_release",
-                       "cgroup.procs",
-                       "cgroup.clone_children",
-                       "cgroup.controllers",
-                       "cgroup.subtree_control",
-                       "cgroup.populated")
-                if (fchownat(fd, fn, arg_uid_shift, arg_uid_shift, 0) < 0)
-                        log_full_errno(errno == ENOENT ? LOG_DEBUG :  LOG_WARNING, errno,
-                                       "Failed to chown() cgroup file %s, ignoring: %m", fn);
-
-        return 0;
-}
-
-static int sync_cgroup(pid_t pid) {
-        _cleanup_free_ char *cgroup = NULL;
-        char tree[] = "/tmp/unifiedXXXXXX", pid_string[DECIMAL_STR_MAX(pid) + 1];
-        bool undo_mount = false;
-        const char *fn;
-        int unified, r;
-
-        unified = cg_unified();
-        if (unified < 0)
-                return log_error_errno(unified, "Failed to determine whether the unified hierachy is used: %m");
-
-        if ((unified > 0) == arg_unified_cgroup_hierarchy)
-                return 0;
-
-        /* When the host uses the legacy cgroup setup, but the
-         * container shall use the unified hierarchy, let's make sure
-         * we copy the path from the name=systemd hierarchy into the
-         * unified hierarchy. Similar for the reverse situation. */
-
-        r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, pid, &cgroup);
-        if (r < 0)
-                return log_error_errno(r, "Failed to get control group of " PID_FMT ": %m", pid);
-
-        /* In order to access the unified hierarchy we need to mount it */
-        if (!mkdtemp(tree))
-                return log_error_errno(errno, "Failed to generate temporary mount point for unified hierarchy: %m");
-
-        if (unified)
-                r = mount("cgroup", tree, "cgroup", MS_NOSUID|MS_NOEXEC|MS_NODEV, "none,name=systemd,xattr");
-        else
-                r = mount("cgroup", tree, "cgroup", MS_NOSUID|MS_NOEXEC|MS_NODEV, "__DEVEL__sane_behavior");
-        if (r < 0) {
-                r = log_error_errno(errno, "Failed to mount unified hierarchy: %m");
-                goto finish;
-        }
-
-        undo_mount = true;
-
-        fn = strjoina(tree, cgroup, "/cgroup.procs");
-        (void) mkdir_parents(fn, 0755);
-
-        sprintf(pid_string, PID_FMT, pid);
-        r = write_string_file(fn, pid_string, 0);
-        if (r < 0)
-                log_error_errno(r, "Failed to move process: %m");
-
-finish:
-        if (undo_mount)
-                (void) umount(tree);
-
-        (void) rmdir(tree);
-        return r;
-}
-
-static int create_subcgroup(pid_t pid) {
-        _cleanup_free_ char *cgroup = NULL;
-        const char *child;
-        int unified, r;
-        CGroupMask supported;
-
-        /* In the unified hierarchy inner nodes may only only contain
-         * subgroups, but not processes. Hence, if we running in the
-         * unified hierarchy and the container does the same, and we
-         * did not create a scope unit for the container move us and
-         * the container into two separate subcgroups. */
-
-        if (!arg_keep_unit)
-                return 0;
-
-        if (!arg_unified_cgroup_hierarchy)
-                return 0;
-
-        unified = cg_unified();
-        if (unified < 0)
-                return log_error_errno(unified, "Failed to determine whether the unified hierachy is used: %m");
-        if (unified == 0)
-                return 0;
-
-        r = cg_mask_supported(&supported);
-        if (r < 0)
-                return log_error_errno(r, "Failed to determine supported controllers: %m");
-
-        r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, 0, &cgroup);
-        if (r < 0)
-                return log_error_errno(r, "Failed to get our control group: %m");
-
-        child = strjoina(cgroup, "/payload");
-        r = cg_create_and_attach(SYSTEMD_CGROUP_CONTROLLER, child, pid);
-        if (r < 0)
-                return log_error_errno(r, "Failed to create %s subcgroup: %m", child);
-
-        child = strjoina(cgroup, "/supervisor");
-        r = cg_create_and_attach(SYSTEMD_CGROUP_CONTROLLER, child, 0);
-        if (r < 0)
-                return log_error_errno(r, "Failed to create %s subcgroup: %m", child);
-
-        /* Try to enable as many controllers as possible for the new payload. */
-        (void) cg_enable_everywhere(supported, supported, cgroup);
-        return 0;
-}
-
 static int load_settings(void) {
         _cleanup_(settings_freep) Settings *settings = NULL;
         _cleanup_fclose_ FILE *f = NULL;
@@ -4042,15 +3908,17 @@ int main(int argc, char *argv[]) {
                 if (r < 0)
                         goto finish;
 
-                r = sync_cgroup(pid);
+                r = sync_cgroup(pid, arg_unified_cgroup_hierarchy);
                 if (r < 0)
                         goto finish;
 
-                r = create_subcgroup(pid);
-                if (r < 0)
-                        goto finish;
+                if (arg_keep_unit) {
+                        r = create_subcgroup(pid, arg_unified_cgroup_hierarchy);
+                        if (r < 0)
+                                goto finish;
+                }
 
-                r = chown_cgroup(pid);
+                r = chown_cgroup(pid, arg_uid_shift);
                 if (r < 0)
                         goto finish;