core: simplify cg_[all_]unified()

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

diff --git a/src/core/cgroup.c b/src/core/cgroup.c
index a524a411004615d6ba67c3ea51419331a5a3c22f..e306b8bceef179c59503ef700b9524ccc68b18d3 100644 (file)
--- a/src/core/cgroup.c
+++ b/src/core/cgroup.c
@@ -288,14 +288,24 @@ static int lookup_block_device(const char *p, dev_t *dev) {
 static int whitelist_device(const char *path, const char *node, const char *acc) {
         char buf[2+DECIMAL_STR_MAX(dev_t)*2+2+4];
         struct stat st;
+        bool ignore_notfound;
         int r;
 
         assert(path);
         assert(acc);
 
+        if (node[0] == '-') {
+                /* Non-existent paths starting with "-" must be silently ignored */
+                node++;
+                ignore_notfound = true;
+        } else
+                ignore_notfound = false;
+
         if (stat(node, &st) < 0) {
-                log_warning("Couldn't stat device %s", node);
-                return -errno;
+                if (errno == ENOENT && ignore_notfound)
+                        return 0;
+
+                return log_warning_errno(errno, "Couldn't stat device %s: %m", node);
         }
 
         if (!S_ISCHR(st.st_mode) && !S_ISBLK(st.st_mode)) {
@@ -669,7 +679,7 @@ static void cgroup_context_apply(Unit *u, CGroupMask mask, ManagerState state) {
                 bool has_weight = cgroup_context_has_cpu_weight(c);
                 bool has_shares = cgroup_context_has_cpu_shares(c);
 
-                if (cg_all_unified() > 0) {
+                if (cg_all_unified()) {
                         uint64_t weight;
 
                         if (has_weight)
@@ -849,7 +859,7 @@ static void cgroup_context_apply(Unit *u, CGroupMask mask, ManagerState state) {
         }
 
         if ((mask & CGROUP_MASK_MEMORY) && !is_root) {
-                if (cg_all_unified() > 0) {
+                if (cg_all_unified()) {
                         uint64_t max;
                         uint64_t swap_max = CGROUP_LIMIT_MAX;
 
@@ -916,8 +926,8 @@ static void cgroup_context_apply(Unit *u, CGroupMask mask, ManagerState state) {
                                 "/dev/pts/ptmx\0" "rw\0" /* /dev/pts/ptmx may not be duplicated, but accessed */
                                 /* Allow /run/elogind/inaccessible/{chr,blk} devices for mapping InaccessiblePaths */
                                 /* Allow /run/systemd/inaccessible/{chr,blk} devices for mapping InaccessiblePaths */
-                                "/run/systemd/inaccessible/chr\0" "rwm\0"
-                                "/run/systemd/inaccessible/blk\0" "rwm\0";
+                                "-/run/systemd/inaccessible/chr\0" "rwm\0"
+                                "-/run/systemd/inaccessible/blk\0" "rwm\0";
 
                         const char *x, *y;
 
@@ -1025,7 +1035,7 @@ CGroupMask unit_get_own_mask(Unit *u) {
                 e = unit_get_exec_context(u);
                 if (!e ||
                     exec_context_maintains_privileges(e) ||
-                    cg_all_unified() > 0)
+                    cg_all_unified())
                         return _CGROUP_MASK_ALL;
         }
 
@@ -1203,9 +1213,10 @@ char *unit_default_cgroup_path(Unit *u) {
                 return NULL;
 
         if (slice)
-                return strjoin(u->manager->cgroup_root, "/", slice, "/", escaped, NULL);
+                return strjoin(u->manager->cgroup_root, "/", slice, "/",
+                               escaped);
         else
-                return strjoin(u->manager->cgroup_root, "/", escaped, NULL);
+                return strjoin(u->manager->cgroup_root, "/", escaped);
 }
 
 int unit_set_cgroup_path(Unit *u, const char *path) {
@@ -1251,10 +1262,7 @@ int unit_watch_cgroup(Unit *u) {
                 return 0;
 
         /* Only applies to the unified hierarchy */
-        r = cg_unified(SYSTEMD_CGROUP_CONTROLLER);
-        if (r < 0)
-                return log_unit_error_errno(u, r, "Failed detect whether the unified hierarchy is used: %m");
-        if (r == 0)
+        if (!cg_unified(SYSTEMD_CGROUP_CONTROLLER))
                 return 0;
 
         /* Don't watch the root slice, it's pointless. */
@@ -1645,7 +1653,7 @@ static int unit_watch_pids_in_path(Unit *u, const char *path) {
                 while ((r = cg_read_subgroup(d, &fn)) > 0) {
                         _cleanup_free_ char *p = NULL;
 
-                        p = strjoin(path, "/", fn, NULL);
+                        p = strjoin(path, "/", fn);
                         free(fn);
 
                         if (!p)
@@ -1674,7 +1682,7 @@ int unit_watch_all_pids(Unit *u) {
         if (!u->cgroup_path)
                 return -ENOENT;
 
-        if (cg_unified(SYSTEMD_CGROUP_CONTROLLER) > 0) /* On unified we can use proper notifications */
+        if (cg_unified(SYSTEMD_CGROUP_CONTROLLER)) /* On unified we can use proper notifications */
                 return 0;
 
         return unit_watch_pids_in_path(u, u->cgroup_path);
@@ -1748,7 +1756,7 @@ static int on_cgroup_inotify_event(sd_event_source *s, int fd, uint32_t revents,
 int manager_setup_cgroup(Manager *m) {
         _cleanup_free_ char *path = NULL;
         CGroupController c;
-        int r, all_unified, systemd_unified;
+        int r;
         char *e;
 
         assert(m);
@@ -1789,16 +1797,13 @@ int manager_setup_cgroup(Manager *m) {
         if (r < 0)
                 return log_error_errno(r, "Cannot find cgroup mount point: %m");
 
-        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,
-                                       "Couldn't determine if we are running in the unified hierarchy: %m");
+        r = cg_unified_flush();
+        if (r < 0)
+                return log_error_errno(r, "Couldn't determine if we are running in the unified hierarchy: %m");
 
-        if (all_unified > 0)
+        if (cg_all_unified())
                 log_debug("Unified cgroup hierarchy is located at %s.", path);
-        else if (systemd_unified > 0)
+        else if (cg_unified(SYSTEMD_CGROUP_CONTROLLER))
                 log_debug("Unified cgroup hierarchy is located at %s. Controllers are on legacy hierarchies.", path);
         else
                 log_debug("Using cgroup controller " SYSTEMD_CGROUP_CONTROLLER ". File system hierarchy is at %s.", path);
@@ -1807,7 +1812,7 @@ int manager_setup_cgroup(Manager *m) {
                 const char *scope_path;
 
                 /* 3. Install agent */
-                if (systemd_unified) {
+                if (cg_unified(SYSTEMD_CGROUP_CONTROLLER)) {
 
                         /* In the unified hierarchy we can get
                          * cgroup empty notifications via inotify. */
@@ -1885,7 +1890,7 @@ int manager_setup_cgroup(Manager *m) {
                         return log_error_errno(errno, "Failed to open pin file: %m");
 
                 /* 6.  Always enable hierarchical support if it exists... */
-                if (!all_unified)
+                if (!cg_all_unified())
                         (void) cg_set_attribute("memory", "/", "memory.use_hierarchy", "1");
         }
 
@@ -2036,7 +2041,7 @@ int unit_get_memory_current(Unit *u, uint64_t *ret) {
         if ((u->cgroup_realized_mask & CGROUP_MASK_MEMORY) == 0)
                 return -ENODATA;
 
-        if (cg_all_unified() <= 0)
+        if (!cg_all_unified())
                 r = cg_get_attribute("memory", u->cgroup_path, "memory.usage_in_bytes", &v);
         else
                 r = cg_get_attribute("memory", u->cgroup_path, "memory.current", &v);
@@ -2081,7 +2086,7 @@ static int unit_get_cpu_usage_raw(Unit *u, nsec_t *ret) {
         if (!u->cgroup_path)
                 return -ENODATA;
 
-        if (cg_all_unified() > 0) {
+        if (cg_all_unified()) {
                 const char *keys[] = { "usage_usec", NULL };
                 _cleanup_free_ char *val = NULL;
                 uint64_t us;