From ef31366523d784d92f25abd99b3782acda29a01c Mon Sep 17 00:00:00 2001
From: xujing <[email protected]>
Date: Fri, 8 Jul 2022 19:47:45 +0800
Subject: [PATCH] support disable cgroup controllers we don't want

---
 src/basic/cgroup-util.c  | 14 +++++++++++
 src/basic/cgroup-util.h  |  1 +
 src/core/cgroup.c        |  1 +
 src/core/main.c          |  7 ++++++
 src/core/manager.h       |  2 ++
 src/core/system.conf.in  |  1 +
 src/shared/conf-parser.c | 54 ++++++++++++++++++++++++++++++++++++++++
 src/shared/conf-parser.h |  1 +
 8 files changed, 81 insertions(+)

diff --git a/src/basic/cgroup-util.c b/src/basic/cgroup-util.c
index 3e60488..a555437 100644
--- a/src/basic/cgroup-util.c
+++ b/src/basic/cgroup-util.c
@@ -2115,6 +2115,20 @@ int cg_mask_supported(CGroupMask *ret) {
         return cg_mask_supported_subtree(root, ret);
 }
 
+int cg_mask_disable_cgroup(CGroupMask disabled, CGroupMask *ret) {
+        int r;
+
+        r = cg_all_unified();
+        if (r < 0)
+                return r;
+
+        /* We only care CGROUP_V1 */
+        if (r == 0)
+                *ret &= ~disabled;
+
+        return 0;
+}
+
 int cg_kernel_controllers(Set **ret) {
         _cleanup_set_free_ Set *controllers = NULL;
         _cleanup_fclose_ FILE *f = NULL;
diff --git a/src/basic/cgroup-util.h b/src/basic/cgroup-util.h
index eb7ace5..3eb14b8 100644
--- a/src/basic/cgroup-util.h
+++ b/src/basic/cgroup-util.h
@@ -303,6 +303,7 @@ typedef const char* (*cg_migrate_callback_t)(CGroupMask mask, void *userdata);
 
 int cg_mask_supported(CGroupMask *ret);
 int cg_mask_supported_subtree(const char *root, CGroupMask *ret);
+int cg_mask_disable_cgroup(CGroupMask disabled, CGroupMask *ret);
 int cg_mask_from_string(const char *s, CGroupMask *ret);
 int cg_mask_to_string(CGroupMask mask, char **ret);
 
diff --git a/src/core/cgroup.c b/src/core/cgroup.c
index 775ece5..88c976a 100644
--- a/src/core/cgroup.c
+++ b/src/core/cgroup.c
@@ -3922,6 +3922,7 @@ int manager_setup_cgroup(Manager *m) {
         if (r < 0)
                 return log_error_errno(r, "Failed to determine supported bpf-based pseudo-controllers: %m");
         m->cgroup_supported |= mask;
+        m->system_cgroup_supported = m->cgroup_supported;
 
         /* 10. Log which controllers are supported */
         for (CGroupController c = 0; c < _CGROUP_CONTROLLER_MAX; c++)
diff --git a/src/core/main.c b/src/core/main.c
index 964adb5..8f01780 100644
--- a/src/core/main.c
+++ b/src/core/main.c
@@ -143,6 +143,7 @@ static bool arg_no_new_privs;
 static nsec_t arg_timer_slack_nsec;
 static Set* arg_syscall_archs;
 static FILE* arg_serialization;
+static CGroupMask arg_disable_cgroup_controllers;
 static sd_id128_t arg_machine_id;
 static EmergencyAction arg_cad_burst_action;
 static CPUSet arg_cpu_affinity;
@@ -675,6 +676,7 @@ static int parse_config_file(void) {
                 { "Manager", "DefaultLimitNICE",             config_parse_rlimit,                RLIMIT_NICE,              arg_defaults.rlimit               },
                 { "Manager", "DefaultLimitRTPRIO",           config_parse_rlimit,                RLIMIT_RTPRIO,            arg_defaults.rlimit               },
                 { "Manager", "DefaultLimitRTTIME",           config_parse_rlimit,                RLIMIT_RTTIME,            arg_defaults.rlimit               },
+                { "Manager", "DisableCGroupControllers",     config_parse_cgroup,                0,                        &arg_disable_cgroup_controllers   },
                 { "Manager", "DefaultCPUAccounting",         config_parse_bool,                  0,                        &arg_defaults.cpu_accounting      },
                 { "Manager", "DefaultIOAccounting",          config_parse_bool,                  0,                        &arg_defaults.io_accounting       },
                 { "Manager", "DefaultIPAccounting",          config_parse_bool,                  0,                        &arg_defaults.ip_accounting       },
@@ -743,6 +745,10 @@ static void set_manager_defaults(Manager *m) {
 
         assert(m);
 
+        m->cgroup_disabled = arg_disable_cgroup_controllers;
+        m->cgroup_supported = m->system_cgroup_supported;
+        (void) cg_mask_disable_cgroup(m->cgroup_disabled, &m->cgroup_supported);
+
         /* Propagates the various default unit property settings into the manager object, i.e. properties
          * that do not affect the manager itself, but are just what newly allocated units will have set if
          * they haven't set anything else. (Also see set_manager_settings() for the settings that affect the
@@ -2518,6 +2524,7 @@ static void reset_arguments(void) {
 
         /* arg_runtime_scope — ignore */
 
+        arg_disable_cgroup_controllers = 0;
         arg_dump_core = true;
         arg_crash_chvt = -1;
         arg_crash_shell = false;
diff --git a/src/core/manager.h b/src/core/manager.h
index 0c9a2ea..65cc0c9 100644
--- a/src/core/manager.h
+++ b/src/core/manager.h
@@ -354,6 +354,8 @@ struct Manager {
         /* Data specific to the cgroup subsystem */
         Hashmap *cgroup_unit;
         CGroupMask cgroup_supported;
+        CGroupMask system_cgroup_supported;
+        CGroupMask cgroup_disabled;
         char *cgroup_root;
 
         /* Notifications from cgroups, when the unified hierarchy is used is done via inotify. */
diff --git a/src/core/system.conf.in b/src/core/system.conf.in
index f48452d..8ffc48e 100644
--- a/src/core/system.conf.in
+++ b/src/core/system.conf.in
@@ -54,6 +54,7 @@
 #DefaultStartLimitIntervalSec=10s
 #DefaultStartLimitBurst=5
 #DefaultEnvironment=
+#DisableCGroupControllers=no
 #DefaultCPUAccounting=yes
 #DefaultIOAccounting=no
 #DefaultIPAccounting=no
diff --git a/src/shared/conf-parser.c b/src/shared/conf-parser.c
index 59a529d..8382271 100644
--- a/src/shared/conf-parser.c
+++ b/src/shared/conf-parser.c
@@ -10,6 +10,7 @@
 #include "alloc-util.h"
 #include "conf-files.h"
 #include "conf-parser.h"
+#include "cgroup-util.h"
 #include "constants.h"
 #include "dns-domain.h"
 #include "escape.h"
@@ -1634,6 +1635,59 @@ int config_parse_rlimit(
         return 0;
 }
 
+int config_parse_cgroup(
+                const char *unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                unsigned section_line,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(data);
+
+        CGroupMask *disabled_mask = data;
+        int r;
+
+        for (;;) {
+                _cleanup_free_ char *word = NULL;
+                CGroupController cc;
+                int yes_or_no = 0;
+
+                r = extract_first_word(&rvalue, &word, NULL, EXTRACT_UNQUOTE|EXTRACT_RETAIN_ESCAPE);
+                if (r == 0)
+                        break;
+                if (r == -ENOMEM)
+                        return log_oom();
+                if (r < 0) {
+                        log_syntax(unit, LOG_ERR, filename, line, r, "Invalid syntax, ignoring: %s", rvalue);
+                        break;
+                }
+
+                yes_or_no = parse_boolean(word);
+                if (yes_or_no == 0) {
+                        *disabled_mask = 0;
+                        break;
+                } else if (yes_or_no == 1) {
+                        *disabled_mask = CGROUP_MASK_V1;
+                        break;
+                }
+
+                cc = cgroup_controller_from_string(word);
+                if (cc < 0) {
+                        log_syntax(unit, LOG_ERR, filename, line, r, "Failed to parse DisableCGroupControllers, ignoring: %s", word);
+                        break;
+                }
+                *disabled_mask |= CGROUP_CONTROLLER_TO_MASK(cc);
+        }
+        return 0;
+}
+
 int config_parse_permille(
                 const char* unit,
                 const char *filename,
diff --git a/src/shared/conf-parser.h b/src/shared/conf-parser.h
index a1768cd..8e7c987 100644
--- a/src/shared/conf-parser.h
+++ b/src/shared/conf-parser.h
@@ -214,6 +214,7 @@ CONFIG_PARSER_PROTOTYPE(config_parse_ifnames);
 CONFIG_PARSER_PROTOTYPE(config_parse_ip_port);
 CONFIG_PARSER_PROTOTYPE(config_parse_mtu);
 CONFIG_PARSER_PROTOTYPE(config_parse_rlimit);
+CONFIG_PARSER_PROTOTYPE(config_parse_cgroup);
 CONFIG_PARSER_PROTOTYPE(config_parse_vlanprotocol);
 CONFIG_PARSER_PROTOTYPE(config_parse_hw_addr);
 CONFIG_PARSER_PROTOTYPE(config_parse_hw_addrs);
-- 
2.33.0