chiark / gitweb /
core: rework logic to determine when we decide to add automatic deps for mounts
[elogind.git] / src / basic / cgroup-util.c
index bcb022896816450bfe101370a6d735e62c235433..1c26c7f8ffd12469125f6a8ef073d6893add66f7 100644 (file)
@@ -210,6 +210,12 @@ int cg_rmdir(const char *controller, const char *path) {
         if (r < 0 && errno != ENOENT)
                 return -errno;
 
+        if (streq(controller, SYSTEMD_CGROUP_CONTROLLER) && cg_hybrid_unified()) {
+                r = cg_rmdir(SYSTEMD_CGROUP_CONTROLLER_LEGACY, path);
+                if (r < 0)
+                        log_warning_errno(r, "Failed to remove compat systemd cgroup %s: %m", path);
+        }
+
         return 0;
 }
 
@@ -548,6 +554,13 @@ static const char *controller_to_dirname(const char *controller) {
          * just cuts off the name= prefixed used for named
          * hierarchies, if it is specified. */
 
+        if (streq(controller, SYSTEMD_CGROUP_CONTROLLER)) {
+                if (cg_hybrid_unified())
+                        controller = SYSTEMD_CGROUP_CONTROLLER_HYBRID;
+                else
+                        controller = SYSTEMD_CGROUP_CONTROLLER_LEGACY;
+        }
+
         e = startswith(controller, "name=");
         if (e)
                 return e;
@@ -706,7 +719,7 @@ static int trim_cb(const char *path, const struct stat *sb, int typeflag, struct
 
 int cg_trim(const char *controller, const char *path, bool delete_root) {
         _cleanup_free_ char *fs = NULL;
-        int r = 0;
+        int r = 0, q;
 
         assert(path);
 
@@ -729,6 +742,12 @@ int cg_trim(const char *controller, const char *path, bool delete_root) {
                         return -errno;
         }
 
+        if (streq(controller, SYSTEMD_CGROUP_CONTROLLER) && cg_hybrid_unified()) {
+                q = cg_trim(SYSTEMD_CGROUP_CONTROLLER_LEGACY, path, delete_root);
+                if (q < 0)
+                        log_warning_errno(q, "Failed to trim compat systemd cgroup %s: %m", path);
+        }
+
         return r;
 }
 
@@ -752,6 +771,12 @@ int cg_create(const char *controller, const char *path) {
                 return -errno;
         }
 
+        if (streq(controller, SYSTEMD_CGROUP_CONTROLLER) && cg_hybrid_unified()) {
+                r = cg_create(SYSTEMD_CGROUP_CONTROLLER_LEGACY, path);
+                if (r < 0)
+                        log_warning_errno(r, "Failed to create compat systemd cgroup %s: %m", path);
+        }
+
         return 1;
 }
 
@@ -789,7 +814,17 @@ int cg_attach(const char *controller, const char *path, pid_t pid) {
 
         xsprintf(c, PID_FMT "\n", pid);
 
-        return write_string_file(fs, c, 0);
+        r = write_string_file(fs, c, 0);
+        if (r < 0)
+                return r;
+
+        if (streq(controller, SYSTEMD_CGROUP_CONTROLLER) && cg_hybrid_unified()) {
+                r = cg_attach(SYSTEMD_CGROUP_CONTROLLER_LEGACY, path, pid);
+                if (r < 0)
+                        log_warning_errno(r, "Failed to attach %d to compat systemd cgroup %s: %m", pid, path);
+        }
+
+        return 0;
 }
 
 int cg_attach_fallback(const char *controller, const char *path, pid_t pid) {
@@ -839,7 +874,17 @@ int cg_set_group_access(
         if (r < 0)
                 return r;
 
-        return chmod_and_chown(fs, mode, uid, gid);
+        r = chmod_and_chown(fs, mode, uid, gid);
+        if (r < 0)
+                return r;
+
+        if (streq(controller, SYSTEMD_CGROUP_CONTROLLER) && cg_hybrid_unified()) {
+                r = cg_set_group_access(SYSTEMD_CGROUP_CONTROLLER_LEGACY, path, mode, uid, gid);
+                if (r < 0)
+                        log_warning_errno(r, "Failed to set group access on compat systemd cgroup %s: %m", path);
+        }
+
+        return 0;
 }
 
 int cg_set_task_access(
@@ -868,13 +913,18 @@ int cg_set_task_access(
         if (r < 0)
                 return r;
 
-        if (cg_unified(controller))
-                return 0;
+        if (!cg_unified(controller)) {
+                /* Compatibility, Always keep values for "tasks" in sync with
+                 * "cgroup.procs" */
+                if (cg_get_path(controller, path, "tasks", &procs) >= 0)
+                        (void) chmod_and_chown(procs, mode, uid, gid);
+        }
 
-        /* Compatibility, Always keep values for "tasks" in sync with
-         * "cgroup.procs" */
-        if (cg_get_path(controller, path, "tasks", &procs) >= 0)
-                (void) chmod_and_chown(procs, mode, uid, gid);
+        if (streq(controller, SYSTEMD_CGROUP_CONTROLLER) && cg_hybrid_unified()) {
+                r = cg_set_task_access(SYSTEMD_CGROUP_CONTROLLER_LEGACY, path, mode, uid, gid);
+                if (r < 0)
+                        log_warning_errno(r, "Failed to set task access on compat systemd cgroup %s: %m", path);
+        }
 
         return 0;
 }
@@ -920,7 +970,7 @@ int cg_get_xattr(const char *controller, const char *path, const char *name, voi
 int cg_pid_get_path(const char *controller, pid_t pid, char **path) {
         _cleanup_fclose_ FILE *f = NULL;
         char line[LINE_MAX];
-        const char *fs;
+        const char *fs, *controller_str;
         size_t cs = 0;
         bool unified;
 
@@ -934,8 +984,14 @@ int cg_pid_get_path(const char *controller, pid_t pid, char **path) {
                 controller = SYSTEMD_CGROUP_CONTROLLER;
 
         unified = cg_unified(controller);
-        if (!unified)
-                cs = strlen(controller);
+        if (!unified) {
+                if (streq(controller, SYSTEMD_CGROUP_CONTROLLER))
+                        controller_str = SYSTEMD_CGROUP_CONTROLLER_LEGACY;
+                else
+                        controller_str = controller;
+
+                cs = strlen(controller_str);
+        }
 
         fs = procfs_file_alloca(pid, "cgroup");
         log_debug_elogind("Searching for PID %u in \"%s\" (controller \"%s\")",
@@ -974,7 +1030,7 @@ int cg_pid_get_path(const char *controller, pid_t pid, char **path) {
 
                         *e = 0;
                         FOREACH_WORD_SEPARATOR(word, k, l, ",", state) {
-                                if (k == cs && memcmp(word, controller, cs) == 0) {
+                                if (k == cs && memcmp(word, controller_str, cs) == 0) {
                                         found = true;
                                         break;
                                 }
@@ -1860,6 +1916,9 @@ bool cg_controller_is_valid(const char *p) {
         if (!p)
                 return false;
 
+        if (streq(p, SYSTEMD_CGROUP_CONTROLLER))
+                return true;
+
         s = startswith(p, "name=");
         if (s)
                 p = s;
@@ -2280,6 +2339,20 @@ int cg_kernel_controllers(Set *controllers) {
 
 static thread_local CGroupUnified unified_cache = CGROUP_UNIFIED_UNKNOWN;
 
+/* The hybrid mode was initially implemented in v232 and simply mounted
+ * cgroup v2 on /sys/fs/cgroup/systemd.  This unfortunately broke other
+ * tools (such as docker) which expected the v1 "name=systemd" hierarchy
+ * on /sys/fs/cgroup/systemd.  From v233 and on, the hybrid mode mountnbs
+ * v2 on /sys/fs/cgroup/unified and maintains "name=systemd" hierarchy
+ * on /sys/fs/cgroup/systemd for compatibility with other tools.
+ *
+ * To keep live upgrade working, we detect and support v232 layout.  When
+ * v232 layout is detected, to keep cgroup v2 process management but
+ * disable the compat dual layout, we return %true on
+ * cg_unified(SYSTEMD_CGROUP_CONTROLLER) and %false on cg_hybrid_unified().
+ */
+static thread_local bool unified_systemd_v232;
+
 static int cg_update_unified(void) {
 
         struct statfs fs;
@@ -2299,11 +2372,21 @@ static int cg_update_unified(void) {
         if (F_TYPE_EQUAL(fs.f_type, CGROUP2_SUPER_MAGIC))
                 unified_cache = CGROUP_UNIFIED_ALL;
         else if (F_TYPE_EQUAL(fs.f_type, TMPFS_MAGIC)) {
-                if (statfs("/sys/fs/cgroup/systemd/", &fs) < 0)
-                        return -errno;
-
-                unified_cache = F_TYPE_EQUAL(fs.f_type, CGROUP2_SUPER_MAGIC) ?
-                        CGROUP_UNIFIED_SYSTEMD : CGROUP_UNIFIED_NONE;
+                if (statfs("/sys/fs/cgroup/unified/", &fs) == 0 &&
+                    F_TYPE_EQUAL(fs.f_type, CGROUP2_SUPER_MAGIC)) {
+                        unified_cache = CGROUP_UNIFIED_SYSTEMD;
+                        unified_systemd_v232 = false;
+                } else if (statfs("/sys/fs/cgroup/systemd/", &fs) == 0 &&
+                           F_TYPE_EQUAL(fs.f_type, CGROUP2_SUPER_MAGIC)) {
+                        unified_cache = CGROUP_UNIFIED_SYSTEMD;
+                        unified_systemd_v232 = true;
+                } else {
+                        if (statfs("/sys/fs/cgroup/systemd/", &fs) < 0)
+                                return -errno;
+                        if (!F_TYPE_EQUAL(fs.f_type, CGROUP_SUPER_MAGIC))
+                                return -ENOMEDIUM;
+                        unified_cache = CGROUP_UNIFIED_NONE;
+                }
         } else
                 return -ENOMEDIUM;
 #else
@@ -2334,6 +2417,13 @@ bool cg_all_unified(void) {
 }
 
 #if 0 /// UNNEEDED by elogind
+bool cg_hybrid_unified(void) {
+
+        assert(cg_update_unified() >= 0);
+
+        return unified_cache == CGROUP_UNIFIED_SYSTEMD && !unified_systemd_v232;
+}
+
 int cg_unified_flush(void) {
         unified_cache = CGROUP_UNIFIED_UNKNOWN;