logind: add infrastructure to keep track of machines, and move to slices

[elogind.git] / src / core / cgroup.c

diff --git a/src/core/cgroup.c b/src/core/cgroup.c
index a248252bcdb26c1eb12000237410ae200d0587df..5065329739d96fae779c0577ced5f145b075c8bd 100644 (file)
--- a/src/core/cgroup.c
+++ b/src/core/cgroup.c
@@ -32,6 +32,7 @@
 #include "log.h"
 #include "strv.h"
 #include "path-util.h"
+#include "special.h"
 
 int cgroup_bonding_realize(CGroupBonding *b) {
         int r;
@@ -304,7 +305,8 @@ int cgroup_bonding_is_empty_list(CGroupBonding *first) {
         LIST_FOREACH(by_unit, b, first) {
                 int r;
 
-                if ((r = cgroup_bonding_is_empty(b)) < 0) {
+                r = cgroup_bonding_is_empty(b);
+                if (r < 0) {
                         /* If this returned -EAGAIN, then we don't know if the
                          * group is empty, so let's see if another group can
                          * tell us */
@@ -319,9 +321,9 @@ int cgroup_bonding_is_empty_list(CGroupBonding *first) {
 }
 
 int manager_setup_cgroup(Manager *m) {
-        _cleanup_free_ char *current = NULL, *path = NULL;
+        _cleanup_free_ char *path = NULL;
         int r;
-        char suffix[sizeof("/systemd-") + DECIMAL_STR_MAX(pid_t)];
+        char *e, *a;
 
         assert(m);
 
@@ -332,34 +334,30 @@ int manager_setup_cgroup(Manager *m) {
         }
 
         /* 1. Determine hierarchy */
-        r = cg_get_by_pid(SYSTEMD_CGROUP_CONTROLLER, 0, &current);
+        free(m->cgroup_root);
+        m->cgroup_root = NULL;
+
+        r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, 0, &m->cgroup_root);
         if (r < 0) {
                 log_error("Cannot determine cgroup we are running in: %s", strerror(-r));
                 return r;
         }
 
-        if (m->running_as == SYSTEMD_SYSTEM)
-                strcpy(suffix, "/system");
-        else {
-                snprintf(suffix, sizeof(suffix), "/systemd-%lu", (unsigned long) getpid());
-                char_array_0(suffix);
+        /* Already in /system.slice? If so, let's cut this off again */
+        if (m->running_as == SYSTEMD_SYSTEM) {
+                e = endswith(m->cgroup_root, "/" SPECIAL_SYSTEM_SLICE);
+                if (e)
+                        *e = 0;
         }
 
-        free(m->cgroup_hierarchy);
-        if (endswith(current, suffix)) {
-                /* We probably got reexecuted and can continue to use our root cgroup */
-                m->cgroup_hierarchy = current;
-                current = NULL;
-
-        } else {
-                /* We need a new root cgroup */
-                m->cgroup_hierarchy = NULL;
-                if (asprintf(&m->cgroup_hierarchy, "%s%s", streq(current, "/") ? "" : current, suffix) < 0)
-                        return log_oom();
-        }
+        /* And make sure to store away the root value without trailing
+         * slash, even for the root dir, so that we can easily prepend
+         * it everywhere. */
+        if (streq(m->cgroup_root, "/"))
+                m->cgroup_root[0] = 0;
 
         /* 2. Show data */
-        r = cg_get_path(SYSTEMD_CGROUP_CONTROLLER, m->cgroup_hierarchy, NULL, &path);
+        r = cg_get_path(SYSTEMD_CGROUP_CONTROLLER, m->cgroup_root, NULL, &path);
         if (r < 0) {
                 log_error("Cannot find cgroup mount point: %s", strerror(-r));
                 return r;
@@ -378,8 +376,9 @@ int manager_setup_cgroup(Manager *m) {
                         log_debug("Release agent already installed.");
         }
 
-        /* 4. Realize the group */
-        r = cg_create_and_attach(SYSTEMD_CGROUP_CONTROLLER, m->cgroup_hierarchy, 0);
+        /* 4. Realize the system slice and put us in there */
+        a = strappenda(m->cgroup_root, "/" SPECIAL_SYSTEM_SLICE);
+        r = cg_create_and_attach(SYSTEMD_CGROUP_CONTROLLER, a, 0);
         if (r < 0) {
                 log_error("Failed to create root cgroup hierarchy: %s", strerror(-r));
                 return r;
@@ -398,30 +397,24 @@ int manager_setup_cgroup(Manager *m) {
         /* 6. Remove non-existing controllers from the default controllers list */
         cg_shorten_controllers(m->default_controllers);
 
-        /* 7. Let's create the user and machine hierarchies
-         * right-away, so that people can inotify on them, if they
-         * wish, without this being racy. */
-        if (m->running_as == SYSTEMD_SYSTEM) {
-                cg_create(SYSTEMD_CGROUP_CONTROLLER, m->cgroup_hierarchy, "../user");
-                cg_create(SYSTEMD_CGROUP_CONTROLLER, m->cgroup_hierarchy, "../machine");
-        }
-
         return 0;
 }
 
 void manager_shutdown_cgroup(Manager *m, bool delete) {
         assert(m);
 
-        if (delete && m->cgroup_hierarchy)
-                cg_delete(SYSTEMD_CGROUP_CONTROLLER, m->cgroup_hierarchy);
+        /* We can't really delete the group, since we are in it. But
+         * let's trim it. */
+        if (delete && m->cgroup_root)
+                cg_trim(SYSTEMD_CGROUP_CONTROLLER, m->cgroup_root, false);
 
         if (m->pin_cgroupfs_fd >= 0) {
                 close_nointr_nofail(m->pin_cgroupfs_fd);
                 m->pin_cgroupfs_fd = -1;
         }
 
-        free(m->cgroup_hierarchy);
-        m->cgroup_hierarchy = NULL;
+        free(m->cgroup_root);
+        m->cgroup_root = NULL;
 }
 
 int cgroup_bonding_get(Manager *m, const char *cgroup, CGroupBonding **bonding) {
@@ -509,7 +502,7 @@ Unit* cgroup_unit_by_pid(Manager *m, pid_t pid) {
         if (pid <= 1)
                 return NULL;
 
-        if (cg_get_by_pid(SYSTEMD_CGROUP_CONTROLLER, pid, &group) < 0)
+        if (cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, pid, &group) < 0)
                 return NULL;
 
         l = hashmap_get(m->cgroup_bondings, group);