From a32360f1a5a85c12f00e9dfb7353280067cccb5b Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Mon, 15 Apr 2013 21:52:56 +0200 Subject: [PATCH 1/1] core: always create /user and /machine top-level cgroup dirs This allows clients to put inotify watches on these trees to watch for state changes, without having to wait until these dirs are created. This introduces the new top-level /machine cgroup dir as canonical location where OS containers and VMs shall be located (as discussed with the libvirt folks). --- src/core/cgroup.c | 52 ++++++++++++++++++++------------------ src/login/logind-session.c | 4 +-- src/login/logind-user.c | 4 +-- src/shared/cgroup-label.c | 6 ++--- src/shared/cgroup-util.h | 2 +- src/test/test-cgroup.c | 8 +++--- 6 files changed, 39 insertions(+), 37 deletions(-) diff --git a/src/core/cgroup.c b/src/core/cgroup.c index b07bd7e6b..a248252bc 100644 --- a/src/core/cgroup.c +++ b/src/core/cgroup.c @@ -40,7 +40,7 @@ int cgroup_bonding_realize(CGroupBonding *b) { assert(b->path); assert(b->controller); - r = cg_create(b->controller, b->path); + r = cg_create(b->controller, b->path, NULL); if (r < 0) { log_warning("Failed to create cgroup %s:%s: %s", b->controller, b->path, strerror(-r)); return r; @@ -319,9 +319,9 @@ int cgroup_bonding_is_empty_list(CGroupBonding *first) { } int manager_setup_cgroup(Manager *m) { - char *current = NULL, *path = NULL; + _cleanup_free_ char *current = NULL, *path = NULL; int r; - char suffix[32]; + char suffix[sizeof("/systemd-") + DECIMAL_STR_MAX(pid_t)]; assert(m); @@ -335,7 +335,7 @@ int manager_setup_cgroup(Manager *m) { r = cg_get_by_pid(SYSTEMD_CGROUP_CONTROLLER, 0, ¤t); if (r < 0) { log_error("Cannot determine cgroup we are running in: %s", strerror(-r)); - goto finish; + return r; } if (m->running_as == SYSTEMD_SYSTEM) @@ -354,35 +354,35 @@ int manager_setup_cgroup(Manager *m) { } else { /* We need a new root cgroup */ m->cgroup_hierarchy = NULL; - if (asprintf(&m->cgroup_hierarchy, "%s%s", streq(current, "/") ? "" : current, suffix) < 0) { - r = log_oom(); - goto finish; - } + if (asprintf(&m->cgroup_hierarchy, "%s%s", streq(current, "/") ? "" : current, suffix) < 0) + return log_oom(); } /* 2. Show data */ r = cg_get_path(SYSTEMD_CGROUP_CONTROLLER, m->cgroup_hierarchy, NULL, &path); if (r < 0) { log_error("Cannot find cgroup mount point: %s", strerror(-r)); - goto finish; + return r; } log_debug("Using cgroup controller " SYSTEMD_CGROUP_CONTROLLER ". File system hierarchy is at %s.", path); /* 3. Install agent */ - r = cg_install_release_agent(SYSTEMD_CGROUP_CONTROLLER, SYSTEMD_CGROUP_AGENT_PATH); - if (r < 0) - log_warning("Failed to install release agent, ignoring: %s", strerror(-r)); - else if (r > 0) - log_debug("Installed release agent."); - else - log_debug("Release agent already installed."); + if (m->running_as == SYSTEMD_SYSTEM) { + r = cg_install_release_agent(SYSTEMD_CGROUP_CONTROLLER, SYSTEMD_CGROUP_AGENT_PATH); + if (r < 0) + log_warning("Failed to install release agent, ignoring: %s", strerror(-r)); + else if (r > 0) + log_debug("Installed release agent."); + else + log_debug("Release agent already installed."); + } /* 4. Realize the group */ r = cg_create_and_attach(SYSTEMD_CGROUP_CONTROLLER, m->cgroup_hierarchy, 0); if (r < 0) { log_error("Failed to create root cgroup hierarchy: %s", strerror(-r)); - goto finish; + return r; } /* 5. And pin it, so that it cannot be unmounted */ @@ -392,19 +392,21 @@ int manager_setup_cgroup(Manager *m) { m->pin_cgroupfs_fd = open(path, O_RDONLY|O_CLOEXEC|O_DIRECTORY|O_NOCTTY|O_NONBLOCK); if (r < 0) { log_error("Failed to open pin file: %m"); - r = -errno; - goto finish; + return -errno; } - log_debug("Created root group."); - + /* 6. Remove non-existing controllers from the default controllers list */ cg_shorten_controllers(m->default_controllers); -finish: - free(current); - free(path); + /* 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 r; + return 0; } void manager_shutdown_cgroup(Manager *m, bool delete) { diff --git a/src/login/logind-session.c b/src/login/logind-session.c index e2f41d3e5..da7ce4201 100644 --- a/src/login/logind-session.c +++ b/src/login/logind-session.c @@ -442,9 +442,9 @@ static int session_create_one_group(Session *s, const char *controller, const ch if (s->leader > 0) { r = cg_create_and_attach(controller, path, s->leader); if (r < 0) - r = cg_create(controller, path); + r = cg_create(controller, path, NULL); } else - r = cg_create(controller, path); + r = cg_create(controller, path, NULL); if (r < 0) return r; diff --git a/src/login/logind-user.c b/src/login/logind-user.c index 411215a92..4b0ac5e73 100644 --- a/src/login/logind-user.c +++ b/src/login/logind-user.c @@ -320,7 +320,7 @@ static int user_create_cgroup(User *u) { } else p = u->cgroup_path; - r = cg_create(SYSTEMD_CGROUP_CONTROLLER, p); + r = cg_create(SYSTEMD_CGROUP_CONTROLLER, p, NULL); if (r < 0) { log_error("Failed to create cgroup "SYSTEMD_CGROUP_CONTROLLER":%s: %s", p, strerror(-r)); free(p); @@ -335,7 +335,7 @@ static int user_create_cgroup(User *u) { if (strv_contains(u->manager->reset_controllers, *k)) continue; - r = cg_create(*k, p); + r = cg_create(*k, p, NULL); if (r < 0) log_warning("Failed to create cgroup %s:%s: %s", *k, p, strerror(-r)); } diff --git a/src/shared/cgroup-label.c b/src/shared/cgroup-label.c index 995e4c57c..a0b486e51 100644 --- a/src/shared/cgroup-label.c +++ b/src/shared/cgroup-label.c @@ -36,14 +36,14 @@ #include "util.h" #include "mkdir.h" -int cg_create(const char *controller, const char *path) { +int cg_create(const char *controller, const char *path, const char *suffix) { _cleanup_free_ char *fs = NULL; int r; assert(controller); assert(path); - r = cg_get_path_and_check(controller, path, NULL, &fs); + r = cg_get_path_and_check(controller, path, suffix, &fs); if (r < 0) return r; @@ -69,7 +69,7 @@ int cg_create_and_attach(const char *controller, const char *path, pid_t pid) { assert(path); assert(pid >= 0); - r = cg_create(controller, path); + r = cg_create(controller, path, NULL); if (r < 0) return r; diff --git a/src/shared/cgroup-util.h b/src/shared/cgroup-util.h index 123f72c69..274380aa2 100644 --- a/src/shared/cgroup-util.h +++ b/src/shared/cgroup-util.h @@ -55,7 +55,7 @@ int cg_trim(const char *controller, const char *path, bool delete_root); int cg_rmdir(const char *controller, const char *path, bool honour_sticky); int cg_delete(const char *controller, const char *path); -int cg_create(const char *controller, const char *path); +int cg_create(const char *controller, const char *path, const char *suffix); int cg_attach(const char *controller, const char *path, pid_t pid); int cg_create_and_attach(const char *controller, const char *path, pid_t pid); diff --git a/src/test/test-cgroup.c b/src/test/test-cgroup.c index 96aca1f7d..2f7cc9be0 100644 --- a/src/test/test-cgroup.c +++ b/src/test/test-cgroup.c @@ -31,10 +31,10 @@ int main(int argc, char*argv[]) { char *path; char *c, *p; - assert_se(cg_create(SYSTEMD_CGROUP_CONTROLLER, "/test-a") == 0); - assert_se(cg_create(SYSTEMD_CGROUP_CONTROLLER, "/test-a") == 0); - assert_se(cg_create(SYSTEMD_CGROUP_CONTROLLER, "/test-b") == 0); - assert_se(cg_create(SYSTEMD_CGROUP_CONTROLLER, "/test-b/test-c") == 0); + assert_se(cg_create(SYSTEMD_CGROUP_CONTROLLER, "/test-a", NULL) == 0); + assert_se(cg_create(SYSTEMD_CGROUP_CONTROLLER, "/test-a", NULL) == 0); + assert_se(cg_create(SYSTEMD_CGROUP_CONTROLLER, "/test-b", NULL) == 0); + assert_se(cg_create(SYSTEMD_CGROUP_CONTROLLER, "/test-b/test-c", NULL) == 0); assert_se(cg_create_and_attach(SYSTEMD_CGROUP_CONTROLLER, "/test-b", 0) == 0); assert_se(cg_get_by_pid(SYSTEMD_CGROUP_CONTROLLER, getpid(), &path) == 0); -- 2.30.2