Merge pull request #3965 from htejun/systemd-controller-on-unified

src/nspawn/nspawn-cgroup.c

@@ -20,7 +20,6 @@
 #include <sys/mount.h>
 
 #include "alloc-util.h"
-#include "cgroup-util.h"
 #include "fd-util.h"
 #include "fileio.h"
 #include "mkdir.h"
@@ -63,18 +62,18 @@ int chown_cgroup(pid_t pid, uid_t uid_shift) {
         return 0;
 }
 
-int sync_cgroup(pid_t pid, bool unified_requested) {
+int sync_cgroup(pid_t pid, CGroupUnified 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();
+        unified = cg_unified(SYSTEMD_CGROUP_CONTROLLER);
         if (unified < 0)
                 return log_error_errno(unified, "Failed to determine whether the unified hierarchy is used: %m");
 
-        if ((unified > 0) == unified_requested)
+        if ((unified > 0) == (unified_requested >= CGROUP_UNIFIED_SYSTEMD))
                 return 0;
 
         /* When the host uses the legacy cgroup setup, but the
@@ -117,7 +116,7 @@ finish:
         return r;
 }
 
-int create_subcgroup(pid_t pid, bool unified_requested) {
+int create_subcgroup(pid_t pid, CGroupUnified unified_requested) {
         _cleanup_free_ char *cgroup = NULL;
         const char *child;
         int unified, r;
@@ -129,10 +128,10 @@ int create_subcgroup(pid_t pid, bool unified_requested) {
          * did not create a scope unit for the container move us and
          * the container into two separate subcgroups. */
 
-        if (!unified_requested)
+        if (unified_requested == CGROUP_UNIFIED_NONE)
                 return 0;
 
-        unified = cg_unified();
+        unified = cg_unified(SYSTEMD_CGROUP_CONTROLLER);
         if (unified < 0)
                 return log_error_errno(unified, "Failed to determine whether the unified hierarchy is used: %m");
         if (unified == 0)

src/nspawn/nspawn-cgroup.h

@@ -22,6 +22,8 @@
 #include <stdbool.h>
 #include <sys/types.h>
 
+#include "cgroup-util.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);
+int sync_cgroup(pid_t pid, CGroupUnified unified_requested);
+int create_subcgroup(pid_t pid, CGroupUnified unified_requested);

src/nspawn/nspawn-mount.c

@@ -21,7 +21,6 @@
 #include <linux/magic.h>
 
 #include "alloc-util.h"
-#include "cgroup-util.h"
 #include "escape.h"
 #include "fd-util.h"
 #include "fileio.h"
@@ -661,7 +660,8 @@ static int get_controllers(Set *subsystems) {
         return 0;
 }
 
-static int mount_legacy_cgroup_hierarchy(const char *dest, const char *controller, const char *hierarchy, bool read_only) {
+static int mount_legacy_cgroup_hierarchy(const char *dest, const char *controller, const char *hierarchy,
+                                         CGroupUnified unified_requested, bool read_only) {
         char *to;
         int r;
 
@@ -677,7 +677,15 @@ static int mount_legacy_cgroup_hierarchy(const char *dest, const char *controlle
 
         /* The superblock mount options of the mount point need to be
          * identical to the hosts', and hence writable... */
-        if (mount("cgroup", to, "cgroup", MS_NOSUID|MS_NOEXEC|MS_NODEV, controller) < 0)
+        if (streq(controller, SYSTEMD_CGROUP_CONTROLLER)) {
+                if (unified_requested >= CGROUP_UNIFIED_SYSTEMD)
+                        r = mount("cgroup", to, "cgroup2", MS_NOSUID|MS_NOEXEC|MS_NODEV, NULL);
+                else
+                        r = mount("cgroup", to, "cgroup", MS_NOSUID|MS_NOEXEC|MS_NODEV, "none,name=systemd,xattr");
+        } else
+                r = mount("cgroup", to, "cgroup", MS_NOSUID|MS_NOEXEC|MS_NODEV, controller);
+
+        if (r < 0)
                 return log_error_errno(errno, "Failed to mount to %s: %m", to);
 
         /* ... hence let's only make the bind mount read-only, not the
@@ -691,8 +699,8 @@ static int mount_legacy_cgroup_hierarchy(const char *dest, const char *controlle
 
 /* Mount a legacy cgroup hierarchy when cgroup namespaces are supported. */
 static int mount_legacy_cgns_supported(
-                bool userns, uid_t uid_shift, uid_t uid_range,
-                const char *selinux_apifs_context) {
+                CGroupUnified unified_requested, bool userns, uid_t uid_shift,
+                uid_t uid_range, const char *selinux_apifs_context) {
         _cleanup_set_free_free_ Set *controllers = NULL;
         const char *cgroup_root = "/sys/fs/cgroup", *c;
         int r;
@@ -721,7 +729,7 @@ static int mount_legacy_cgns_supported(
                         return log_error_errno(errno, "Failed to mount /sys/fs/cgroup: %m");
         }
 
-        if (cg_unified() > 0)
+        if (cg_all_unified() > 0)
                 goto skip_controllers;
 
         controllers = set_new(&string_hash_ops);
@@ -739,7 +747,7 @@ static int mount_legacy_cgns_supported(
                 if (!controller)
                         break;
 
-                r = mount_legacy_cgroup_hierarchy("", controller, controller, !userns);
+                r = mount_legacy_cgroup_hierarchy("", controller, controller, unified_requested, !userns);
                 if (r < 0)
                         return r;
 
@@ -773,7 +781,7 @@ static int mount_legacy_cgns_supported(
         }
 
 skip_controllers:
-        r = mount_legacy_cgroup_hierarchy("", "none,name=systemd,xattr", "systemd", false);
+        r = mount_legacy_cgroup_hierarchy("", SYSTEMD_CGROUP_CONTROLLER, "systemd", unified_requested, false);
         if (r < 0)
                 return r;
 
@@ -788,7 +796,7 @@ skip_controllers:
 /* Mount legacy cgroup hierarchy when cgroup namespaces are unsupported. */
 static int mount_legacy_cgns_unsupported(
                 const char *dest,
-                bool userns, uid_t uid_shift, uid_t uid_range,
+                CGroupUnified unified_requested, bool userns, uid_t uid_shift, uid_t uid_range,
                 const char *selinux_apifs_context) {
         _cleanup_set_free_free_ Set *controllers = NULL;
         const char *cgroup_root;
@@ -813,7 +821,7 @@ static int mount_legacy_cgns_unsupported(
                         return log_error_errno(errno, "Failed to mount /sys/fs/cgroup: %m");
         }
 
-        if (cg_unified() > 0)
+        if (cg_all_unified() > 0)
                 goto skip_controllers;
 
         controllers = set_new(&string_hash_ops);
@@ -839,7 +847,7 @@ static int mount_legacy_cgns_unsupported(
                 if (r == -EINVAL) {
                         /* Not a symbolic link, but directly a single cgroup hierarchy */
 
-                        r = mount_legacy_cgroup_hierarchy(dest, controller, controller, true);
+                        r = mount_legacy_cgroup_hierarchy(dest, controller, controller, unified_requested, true);
                         if (r < 0)
                                 return r;
 
@@ -859,7 +867,7 @@ static int mount_legacy_cgns_unsupported(
                                 continue;
                         }
 
-                        r = mount_legacy_cgroup_hierarchy(dest, combined, combined, true);
+                        r = mount_legacy_cgroup_hierarchy(dest, combined, combined, unified_requested, true);
                         if (r < 0)
                                 return r;
 
@@ -872,7 +880,7 @@ static int mount_legacy_cgns_unsupported(
         }
 
 skip_controllers:
-        r = mount_legacy_cgroup_hierarchy(dest, "none,name=systemd,xattr", "systemd", false);
+        r = mount_legacy_cgroup_hierarchy(dest, SYSTEMD_CGROUP_CONTROLLER, "systemd", unified_requested, false);
         if (r < 0)
                 return r;
 
@@ -914,22 +922,22 @@ static int mount_unified_cgroups(const char *dest) {
 
 int mount_cgroups(
                 const char *dest,
-                bool unified_requested,
+                CGroupUnified unified_requested,
                 bool userns, uid_t uid_shift, uid_t uid_range,
                 const char *selinux_apifs_context,
                 bool use_cgns) {
 
-        if (unified_requested)
+        if (unified_requested >= CGROUP_UNIFIED_ALL)
                 return mount_unified_cgroups(dest);
         else if (use_cgns && cg_ns_supported())
-                return mount_legacy_cgns_supported(userns, uid_shift, uid_range, selinux_apifs_context);
+                return mount_legacy_cgns_supported(unified_requested, userns, uid_shift, uid_range, selinux_apifs_context);
 
-        return mount_legacy_cgns_unsupported(dest, userns, uid_shift, uid_range, selinux_apifs_context);
+        return mount_legacy_cgns_unsupported(dest, unified_requested, userns, uid_shift, uid_range, selinux_apifs_context);
 }
 
 int mount_systemd_cgroup_writable(
                 const char *dest,
-                bool unified_requested) {
+                CGroupUnified unified_requested) {
 
         _cleanup_free_ char *own_cgroup_path = NULL;
         const char *systemd_root, *systemd_own;
@@ -945,7 +953,7 @@ int mount_systemd_cgroup_writable(
         if (path_equal(own_cgroup_path, "/"))
                 return 0;
 
-        if (unified_requested) {
+        if (unified_requested >= CGROUP_UNIFIED_ALL) {
                 systemd_own = strjoina(dest, "/sys/fs/cgroup", own_cgroup_path);
                 systemd_root = prefix_roota(dest, "/sys/fs/cgroup");
         } else {

src/nspawn/nspawn-mount.h

@@ -21,6 +21,8 @@
 
 #include <stdbool.h>
 
+#include "cgroup-util.h"
+
 typedef enum VolatileMode {
         VOLATILE_NO,
         VOLATILE_YES,
@@ -58,8 +60,8 @@ int custom_mount_compare(const void *a, const void *b);
 int mount_all(const char *dest, bool use_userns, bool in_userns, bool use_netns, uid_t uid_shift, uid_t uid_range, const char *selinux_apifs_context);
 int mount_sysfs(const char *dest);
 
-int mount_cgroups(const char *dest, bool unified_requested, bool userns, uid_t uid_shift, uid_t uid_range, const char *selinux_apifs_context, bool use_cgns);
-int mount_systemd_cgroup_writable(const char *dest, bool unified_requested);
+int mount_cgroups(const char *dest, CGroupUnified unified_requested, bool userns, uid_t uid_shift, uid_t uid_range, const char *selinux_apifs_context, bool use_cgns);
+int mount_systemd_cgroup_writable(const char *dest, CGroupUnified unified_requested);
 
 int mount_custom(const char *dest, CustomMount *mounts, unsigned n, bool userns, uid_t uid_shift, uid_t uid_range, const char *selinux_apifs_context);
 

src/nspawn/nspawn.c

@@ -188,7 +188,7 @@ static UserNamespaceMode arg_userns_mode = USER_NAMESPACE_NO;
 static uid_t arg_uid_shift = UID_INVALID, arg_uid_range = 0x10000U;
 static bool arg_userns_chown = false;
 static int arg_kill_signal = 0;
-static bool arg_unified_cgroup_hierarchy = false;
+static CGroupUnified arg_unified_cgroup_hierarchy = CGROUP_UNIFIED_UNKNOWN;
 static SettingsMask arg_settings_mask = 0;
 static int arg_settings_trusted = -1;
 static char **arg_parameters = NULL;
@@ -318,7 +318,14 @@ static int custom_mounts_prepare(void) {
 
 static int detect_unified_cgroup_hierarchy(void) {
         const char *e;
-        int r;
+        int r, all_unified, systemd_unified;
+
+        all_unified = cg_all_unified();
+        systemd_unified = cg_unified(SYSTEMD_CGROUP_CONTROLLER);
+
+        if (all_unified < 0 || systemd_unified < 0)
+                return log_error_errno(all_unified < 0 ? all_unified : systemd_unified,
+                                       "Failed to determine whether the unified cgroups hierarchy is used: %m");
 
         /* Allow the user to control whether the unified hierarchy is used */
         e = getenv("UNIFIED_CGROUP_HIERARCHY");
@@ -326,17 +333,22 @@ static int detect_unified_cgroup_hierarchy(void) {
                 r = parse_boolean(e);
                 if (r < 0)
                         return log_error_errno(r, "Failed to parse $UNIFIED_CGROUP_HIERARCHY.");
+                if (r > 0)
+                        arg_unified_cgroup_hierarchy = CGROUP_UNIFIED_ALL;
+                else
+                        arg_unified_cgroup_hierarchy = CGROUP_UNIFIED_NONE;
 
-                arg_unified_cgroup_hierarchy = r;
                 return 0;
         }
 
         /* Otherwise inherit the default from the host system */
-        r = cg_unified();
-        if (r < 0)
-                return log_error_errno(r, "Failed to determine whether the unified cgroups hierarchy is used: %m");
+        if (all_unified > 0)
+                arg_unified_cgroup_hierarchy = CGROUP_UNIFIED_ALL;
+        else if (systemd_unified > 0)
+                arg_unified_cgroup_hierarchy = CGROUP_UNIFIED_SYSTEMD;
+        else
+                arg_unified_cgroup_hierarchy = CGROUP_UNIFIED_NONE;
 
-        arg_unified_cgroup_hierarchy = r;
         return 0;
 }