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cgroup: change cg_unified() to possibly return errors again

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We use our cgroup APIs in various contexts, including from our libraries
sd-login, sd-bus. As we don#t control those environments we can't rely
that the unified cgroup setup logic succeeds, and hence really shouldn't
assert on it.

This more or less reverts 415fc41cea.
This commit is contained in:
Lennart Poettering
2017-02-24 17:52:58 +01:00
parent fc9ae7178e
commit b4cccbc13a
12 changed files with 184 additions and 74 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/basic/cgroup-util.c
+97 -30
View File
@@ -208,7 +208,13 @@ 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_hybrid_unified();
if (r < 0)
return r;
if (r == 0)
return 0;
if (streq(controller, SYSTEMD_CGROUP_CONTROLLER)) {
r = cg_rmdir(SYSTEMD_CGROUP_CONTROLLER_LEGACY, path);
if (r < 0)
log_warning_errno(r, "Failed to remove compat systemd cgroup %s: %m", path);
@@ -549,7 +555,7 @@ static const char *controller_to_dirname(const char *controller) {
* hierarchies, if it is specified. */
if (streq(controller, SYSTEMD_CGROUP_CONTROLLER)) {
if (cg_hybrid_unified())
if (cg_hybrid_unified() > 0)
controller = SYSTEMD_CGROUP_CONTROLLER_HYBRID;
else
controller = SYSTEMD_CGROUP_CONTROLLER_LEGACY;
@@ -636,7 +642,10 @@ int cg_get_path(const char *controller, const char *path, const char *suffix, ch
if (!cg_controller_is_valid(controller))
return -EINVAL;
if (cg_all_unified())
r = cg_all_unified();
if (r < 0)
return r;
if (r > 0)
r = join_path_unified(path, suffix, fs);
else
r = join_path_legacy(controller, path, suffix, fs);
@@ -648,6 +657,7 @@ int cg_get_path(const char *controller, const char *path, const char *suffix, ch
}
static int controller_is_accessible(const char *controller) {
int r;
assert(controller);
@@ -659,7 +669,10 @@ static int controller_is_accessible(const char *controller) {
if (!cg_controller_is_valid(controller))
return -EINVAL;
if (cg_all_unified()) {
r = cg_all_unified();
if (r < 0)
return r;
if (r > 0) {
/* We don't support named hierarchies if we are using
* the unified hierarchy. */
@@ -736,7 +749,10 @@ 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_hybrid_unified();
if (q < 0)
return q;
if (q > 0 && streq(controller, SYSTEMD_CGROUP_CONTROLLER)) {
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);
@@ -765,7 +781,11 @@ int cg_create(const char *controller, const char *path) {
return -errno;
}
if (streq(controller, SYSTEMD_CGROUP_CONTROLLER) && cg_hybrid_unified()) {
r = cg_hybrid_unified();
if (r < 0)
return r;
if (r > 0 && streq(controller, SYSTEMD_CGROUP_CONTROLLER)) {
r = cg_create(SYSTEMD_CGROUP_CONTROLLER_LEGACY, path);
if (r < 0)
log_warning_errno(r, "Failed to create compat systemd cgroup %s: %m", path);
@@ -812,7 +832,11 @@ int cg_attach(const char *controller, const char *path, pid_t pid) {
if (r < 0)
return r;
if (streq(controller, SYSTEMD_CGROUP_CONTROLLER) && cg_hybrid_unified()) {
r = cg_hybrid_unified();
if (r < 0)
return r;
if (r > 0 && streq(controller, SYSTEMD_CGROUP_CONTROLLER)) {
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);
@@ -871,7 +895,10 @@ int cg_set_group_access(
if (r < 0)
return r;
if (streq(controller, SYSTEMD_CGROUP_CONTROLLER) && cg_hybrid_unified()) {
r = cg_hybrid_unified();
if (r < 0)
return r;
if (r > 0 && streq(controller, SYSTEMD_CGROUP_CONTROLLER)) {
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);
@@ -906,14 +933,20 @@ int cg_set_task_access(
if (r < 0)
return r;
if (!cg_unified(controller)) {
r = cg_unified(controller);
if (r < 0)
return r;
if (r == 0) {
/* 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_hybrid_unified();
if (r < 0)
return r;
if (r > 0 && streq(controller, SYSTEMD_CGROUP_CONTROLLER)) {
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);
@@ -964,7 +997,7 @@ int cg_pid_get_path(const char *controller, pid_t pid, char **path) {
char line[LINE_MAX];
const char *fs, *controller_str;
size_t cs = 0;
bool unified;
int unified;
assert(path);
assert(pid >= 0);
@@ -976,7 +1009,9 @@ int cg_pid_get_path(const char *controller, pid_t pid, char **path) {
controller = SYSTEMD_CGROUP_CONTROLLER;
unified = cg_unified(controller);
if (!unified) {
if (unified < 0)
return unified;
if (unified == 0) {
if (streq(controller, SYSTEMD_CGROUP_CONTROLLER))
controller_str = SYSTEMD_CGROUP_CONTROLLER_LEGACY;
else
@@ -1048,7 +1083,10 @@ int cg_install_release_agent(const char *controller, const char *agent) {
assert(agent);
if (cg_unified(controller)) /* doesn't apply to unified hierarchy */
r = cg_unified(controller);
if (r < 0)
return r;
if (r > 0) /* doesn't apply to unified hierarchy */
return -EOPNOTSUPP;
r = cg_get_path(controller, NULL, "release_agent", &fs);
@@ -1096,7 +1134,10 @@ int cg_uninstall_release_agent(const char *controller) {
_cleanup_free_ char *fs = NULL;
int r;
if (cg_unified(controller)) /* Doesn't apply to unified hierarchy */
r = cg_unified(controller);
if (r < 0)
return r;
if (r > 0) /* Doesn't apply to unified hierarchy */
return -EOPNOTSUPP;
r = cg_get_path(controller, NULL, "notify_on_release", &fs);
@@ -1149,7 +1190,10 @@ int cg_is_empty_recursive(const char *controller, const char *path) {
if (controller && (isempty(path) || path_equal(path, "/")))
return false;
if (cg_unified(controller)) {
r = cg_unified(controller);
if (r < 0)
return r;
if (r > 0) {
_cleanup_free_ char *t = NULL;
/* On the unified hierarchy we can check empty state
@@ -2034,7 +2078,10 @@ int cg_create_everywhere(CGroupMask supported, CGroupMask mask, const char *path
return r;
/* If we are in the unified hierarchy, we are done now */
if (cg_all_unified())
r = cg_all_unified();
if (r < 0)
return r;
if (r > 0)
return 0;
/* Otherwise, do the same in the other hierarchies */
@@ -2061,7 +2108,10 @@ int cg_attach_everywhere(CGroupMask supported, const char *path, pid_t pid, cg_m
if (r < 0)
return r;
if (cg_all_unified())
r = cg_all_unified();
if (r < 0)
return r;
if (r > 0)
return 0;
for (c = 0; c < _CGROUP_CONTROLLER_MAX; c++) {
@@ -2102,7 +2152,7 @@ int cg_attach_many_everywhere(CGroupMask supported, const char *path, Set* pids,
int cg_migrate_everywhere(CGroupMask supported, const char *from, const char *to, cg_migrate_callback_t to_callback, void *userdata) {
CGroupController c;
int r = 0;
int r = 0, q;
if (!path_equal(from, to)) {
r = cg_migrate_recursive(SYSTEMD_CGROUP_CONTROLLER, from, SYSTEMD_CGROUP_CONTROLLER, to, CGROUP_REMOVE);
@@ -2110,7 +2160,10 @@ int cg_migrate_everywhere(CGroupMask supported, const char *from, const char *to
return r;
}
if (cg_all_unified())
q = cg_all_unified();
if (q < 0)
return q;
if (q > 0)
return r;
for (c = 0; c < _CGROUP_CONTROLLER_MAX; c++) {
@@ -2134,13 +2187,16 @@ int cg_migrate_everywhere(CGroupMask supported, const char *from, const char *to
int cg_trim_everywhere(CGroupMask supported, const char *path, bool delete_root) {
CGroupController c;
int r;
int r, q;
r = cg_trim(SYSTEMD_CGROUP_CONTROLLER, path, delete_root);
if (r < 0)
return r;
if (cg_all_unified())
q = cg_all_unified();
if (q < 0)
return q;
if (q > 0)
return r;
for (c = 0; c < _CGROUP_CONTROLLER_MAX; c++) {
@@ -2163,7 +2219,10 @@ int cg_mask_supported(CGroupMask *ret) {
* includes controllers we can make sense of and that are
* actually accessible. */
if (cg_all_unified()) {
r = cg_all_unified();
if (r < 0)
return r;
if (r > 0) {
_cleanup_free_ char *root = NULL, *controllers = NULL, *path = NULL;
const char *c;
@@ -2336,9 +2395,12 @@ static int cg_update_unified(void) {
return 0;
}
bool cg_unified(const char *controller) {
int cg_unified(const char *controller) {
int r;
assert(cg_update_unified() >= 0);
r = cg_update_unified();
if (r < 0)
return r;
if (unified_cache == CGROUP_UNIFIED_NONE)
return false;
@@ -2349,14 +2411,16 @@ bool cg_unified(const char *controller) {
return streq_ptr(controller, SYSTEMD_CGROUP_CONTROLLER);
}
bool cg_all_unified(void) {
int cg_all_unified(void) {
return cg_unified(NULL);
}
bool cg_hybrid_unified(void) {
int cg_hybrid_unified(void) {
int r;
assert(cg_update_unified() >= 0);
r = cg_update_unified();
if (r < 0)
return r;
return unified_cache == CGROUP_UNIFIED_SYSTEMD && !unified_systemd_v232;
}
@@ -2377,7 +2441,10 @@ int cg_enable_everywhere(CGroupMask supported, CGroupMask mask, const char *p) {
if (supported == 0)
return 0;
if (!cg_all_unified()) /* on the legacy hiearchy there's no joining of controllers defined */
r = cg_all_unified();
if (r < 0)
return r;
if (r == 0) /* on the legacy hiearchy there's no joining of controllers defined */
return 0;
r = cg_get_path(SYSTEMD_CGROUP_CONTROLLER, p, "cgroup.subtree_control", &fs);
@@ -2420,7 +2487,7 @@ bool cg_is_unified_wanted(void) {
/* If the hierarchy is already mounted, then follow whatever
* was chosen for it. */
if (cg_unified_flush() >= 0)
return (wanted = cg_all_unified());
return (wanted = unified_cache >= CGROUP_UNIFIED_ALL);
/* Otherwise, let's see what the kernel command line has to say.
* Since checking is expensive, cache a non-error result. */