174bd59bbSPavel Emelyanov /* 274bd59bbSPavel Emelyanov * Pid namespaces 374bd59bbSPavel Emelyanov * 474bd59bbSPavel Emelyanov * Authors: 574bd59bbSPavel Emelyanov * (C) 2007 Pavel Emelyanov <xemul@openvz.org>, OpenVZ, SWsoft Inc. 674bd59bbSPavel Emelyanov * (C) 2007 Sukadev Bhattiprolu <sukadev@us.ibm.com>, IBM 774bd59bbSPavel Emelyanov * Many thanks to Oleg Nesterov for comments and help 874bd59bbSPavel Emelyanov * 974bd59bbSPavel Emelyanov */ 1074bd59bbSPavel Emelyanov 1174bd59bbSPavel Emelyanov #include <linux/pid.h> 1274bd59bbSPavel Emelyanov #include <linux/pid_namespace.h> 1374bd59bbSPavel Emelyanov #include <linux/syscalls.h> 1474bd59bbSPavel Emelyanov #include <linux/err.h> 1574bd59bbSPavel Emelyanov 1674bd59bbSPavel Emelyanov #define BITS_PER_PAGE (PAGE_SIZE*8) 1774bd59bbSPavel Emelyanov 1874bd59bbSPavel Emelyanov struct pid_cache { 1974bd59bbSPavel Emelyanov int nr_ids; 2074bd59bbSPavel Emelyanov char name[16]; 2174bd59bbSPavel Emelyanov struct kmem_cache *cachep; 2274bd59bbSPavel Emelyanov struct list_head list; 2374bd59bbSPavel Emelyanov }; 2474bd59bbSPavel Emelyanov 2574bd59bbSPavel Emelyanov static LIST_HEAD(pid_caches_lh); 2674bd59bbSPavel Emelyanov static DEFINE_MUTEX(pid_caches_mutex); 2774bd59bbSPavel Emelyanov static struct kmem_cache *pid_ns_cachep; 2874bd59bbSPavel Emelyanov 2974bd59bbSPavel Emelyanov /* 3074bd59bbSPavel Emelyanov * creates the kmem cache to allocate pids from. 3174bd59bbSPavel Emelyanov * @nr_ids: the number of numerical ids this pid will have to carry 3274bd59bbSPavel Emelyanov */ 3374bd59bbSPavel Emelyanov 3474bd59bbSPavel Emelyanov static struct kmem_cache *create_pid_cachep(int nr_ids) 3574bd59bbSPavel Emelyanov { 3674bd59bbSPavel Emelyanov struct pid_cache *pcache; 3774bd59bbSPavel Emelyanov struct kmem_cache *cachep; 3874bd59bbSPavel Emelyanov 3974bd59bbSPavel Emelyanov mutex_lock(&pid_caches_mutex); 4074bd59bbSPavel Emelyanov list_for_each_entry(pcache, &pid_caches_lh, list) 4174bd59bbSPavel Emelyanov if (pcache->nr_ids == nr_ids) 4274bd59bbSPavel Emelyanov goto out; 4374bd59bbSPavel Emelyanov 4474bd59bbSPavel Emelyanov pcache = kmalloc(sizeof(struct pid_cache), GFP_KERNEL); 4574bd59bbSPavel Emelyanov if (pcache == NULL) 4674bd59bbSPavel Emelyanov goto err_alloc; 4774bd59bbSPavel Emelyanov 4874bd59bbSPavel Emelyanov snprintf(pcache->name, sizeof(pcache->name), "pid_%d", nr_ids); 4974bd59bbSPavel Emelyanov cachep = kmem_cache_create(pcache->name, 5074bd59bbSPavel Emelyanov sizeof(struct pid) + (nr_ids - 1) * sizeof(struct upid), 5174bd59bbSPavel Emelyanov 0, SLAB_HWCACHE_ALIGN, NULL); 5274bd59bbSPavel Emelyanov if (cachep == NULL) 5374bd59bbSPavel Emelyanov goto err_cachep; 5474bd59bbSPavel Emelyanov 5574bd59bbSPavel Emelyanov pcache->nr_ids = nr_ids; 5674bd59bbSPavel Emelyanov pcache->cachep = cachep; 5774bd59bbSPavel Emelyanov list_add(&pcache->list, &pid_caches_lh); 5874bd59bbSPavel Emelyanov out: 5974bd59bbSPavel Emelyanov mutex_unlock(&pid_caches_mutex); 6074bd59bbSPavel Emelyanov return pcache->cachep; 6174bd59bbSPavel Emelyanov 6274bd59bbSPavel Emelyanov err_cachep: 6374bd59bbSPavel Emelyanov kfree(pcache); 6474bd59bbSPavel Emelyanov err_alloc: 6574bd59bbSPavel Emelyanov mutex_unlock(&pid_caches_mutex); 6674bd59bbSPavel Emelyanov return NULL; 6774bd59bbSPavel Emelyanov } 6874bd59bbSPavel Emelyanov 69caafa432SPavel Emelyanov static struct pid_namespace *create_pid_namespace(unsigned int level) 7074bd59bbSPavel Emelyanov { 7174bd59bbSPavel Emelyanov struct pid_namespace *ns; 7274bd59bbSPavel Emelyanov int i; 7374bd59bbSPavel Emelyanov 7484406c15SPavel Emelyanov ns = kmem_cache_zalloc(pid_ns_cachep, GFP_KERNEL); 7574bd59bbSPavel Emelyanov if (ns == NULL) 7674bd59bbSPavel Emelyanov goto out; 7774bd59bbSPavel Emelyanov 7874bd59bbSPavel Emelyanov ns->pidmap[0].page = kzalloc(PAGE_SIZE, GFP_KERNEL); 7974bd59bbSPavel Emelyanov if (!ns->pidmap[0].page) 8074bd59bbSPavel Emelyanov goto out_free; 8174bd59bbSPavel Emelyanov 8274bd59bbSPavel Emelyanov ns->pid_cachep = create_pid_cachep(level + 1); 8374bd59bbSPavel Emelyanov if (ns->pid_cachep == NULL) 8474bd59bbSPavel Emelyanov goto out_free_map; 8574bd59bbSPavel Emelyanov 8674bd59bbSPavel Emelyanov kref_init(&ns->kref); 8774bd59bbSPavel Emelyanov ns->level = level; 8874bd59bbSPavel Emelyanov 8974bd59bbSPavel Emelyanov set_bit(0, ns->pidmap[0].page); 9074bd59bbSPavel Emelyanov atomic_set(&ns->pidmap[0].nr_free, BITS_PER_PAGE - 1); 9174bd59bbSPavel Emelyanov 9284406c15SPavel Emelyanov for (i = 1; i < PIDMAP_ENTRIES; i++) 9374bd59bbSPavel Emelyanov atomic_set(&ns->pidmap[i].nr_free, BITS_PER_PAGE); 9474bd59bbSPavel Emelyanov 9574bd59bbSPavel Emelyanov return ns; 9674bd59bbSPavel Emelyanov 9774bd59bbSPavel Emelyanov out_free_map: 9874bd59bbSPavel Emelyanov kfree(ns->pidmap[0].page); 9974bd59bbSPavel Emelyanov out_free: 10074bd59bbSPavel Emelyanov kmem_cache_free(pid_ns_cachep, ns); 10174bd59bbSPavel Emelyanov out: 10274bd59bbSPavel Emelyanov return ERR_PTR(-ENOMEM); 10374bd59bbSPavel Emelyanov } 10474bd59bbSPavel Emelyanov 10574bd59bbSPavel Emelyanov static void destroy_pid_namespace(struct pid_namespace *ns) 10674bd59bbSPavel Emelyanov { 10774bd59bbSPavel Emelyanov int i; 10874bd59bbSPavel Emelyanov 10974bd59bbSPavel Emelyanov for (i = 0; i < PIDMAP_ENTRIES; i++) 11074bd59bbSPavel Emelyanov kfree(ns->pidmap[i].page); 11174bd59bbSPavel Emelyanov kmem_cache_free(pid_ns_cachep, ns); 11274bd59bbSPavel Emelyanov } 11374bd59bbSPavel Emelyanov 11474bd59bbSPavel Emelyanov struct pid_namespace *copy_pid_ns(unsigned long flags, struct pid_namespace *old_ns) 11574bd59bbSPavel Emelyanov { 11674bd59bbSPavel Emelyanov struct pid_namespace *new_ns; 11774bd59bbSPavel Emelyanov 11874bd59bbSPavel Emelyanov BUG_ON(!old_ns); 11974bd59bbSPavel Emelyanov new_ns = get_pid_ns(old_ns); 12074bd59bbSPavel Emelyanov if (!(flags & CLONE_NEWPID)) 12174bd59bbSPavel Emelyanov goto out; 12274bd59bbSPavel Emelyanov 12374bd59bbSPavel Emelyanov new_ns = ERR_PTR(-EINVAL); 12474bd59bbSPavel Emelyanov if (flags & CLONE_THREAD) 12574bd59bbSPavel Emelyanov goto out_put; 12674bd59bbSPavel Emelyanov 12774bd59bbSPavel Emelyanov new_ns = create_pid_namespace(old_ns->level + 1); 12874bd59bbSPavel Emelyanov if (!IS_ERR(new_ns)) 12974bd59bbSPavel Emelyanov new_ns->parent = get_pid_ns(old_ns); 13074bd59bbSPavel Emelyanov 13174bd59bbSPavel Emelyanov out_put: 13274bd59bbSPavel Emelyanov put_pid_ns(old_ns); 13374bd59bbSPavel Emelyanov out: 13474bd59bbSPavel Emelyanov return new_ns; 13574bd59bbSPavel Emelyanov } 13674bd59bbSPavel Emelyanov 13774bd59bbSPavel Emelyanov void free_pid_ns(struct kref *kref) 13874bd59bbSPavel Emelyanov { 13974bd59bbSPavel Emelyanov struct pid_namespace *ns, *parent; 14074bd59bbSPavel Emelyanov 14174bd59bbSPavel Emelyanov ns = container_of(kref, struct pid_namespace, kref); 14274bd59bbSPavel Emelyanov 14374bd59bbSPavel Emelyanov parent = ns->parent; 14474bd59bbSPavel Emelyanov destroy_pid_namespace(ns); 14574bd59bbSPavel Emelyanov 14674bd59bbSPavel Emelyanov if (parent != NULL) 14774bd59bbSPavel Emelyanov put_pid_ns(parent); 14874bd59bbSPavel Emelyanov } 14974bd59bbSPavel Emelyanov 15074bd59bbSPavel Emelyanov void zap_pid_ns_processes(struct pid_namespace *pid_ns) 15174bd59bbSPavel Emelyanov { 15274bd59bbSPavel Emelyanov int nr; 15374bd59bbSPavel Emelyanov int rc; 15474bd59bbSPavel Emelyanov 15574bd59bbSPavel Emelyanov /* 15674bd59bbSPavel Emelyanov * The last thread in the cgroup-init thread group is terminating. 15774bd59bbSPavel Emelyanov * Find remaining pid_ts in the namespace, signal and wait for them 15874bd59bbSPavel Emelyanov * to exit. 15974bd59bbSPavel Emelyanov * 16074bd59bbSPavel Emelyanov * Note: This signals each threads in the namespace - even those that 16174bd59bbSPavel Emelyanov * belong to the same thread group, To avoid this, we would have 16274bd59bbSPavel Emelyanov * to walk the entire tasklist looking a processes in this 16374bd59bbSPavel Emelyanov * namespace, but that could be unnecessarily expensive if the 16474bd59bbSPavel Emelyanov * pid namespace has just a few processes. Or we need to 16574bd59bbSPavel Emelyanov * maintain a tasklist for each pid namespace. 16674bd59bbSPavel Emelyanov * 16774bd59bbSPavel Emelyanov */ 16874bd59bbSPavel Emelyanov read_lock(&tasklist_lock); 16974bd59bbSPavel Emelyanov nr = next_pidmap(pid_ns, 1); 17074bd59bbSPavel Emelyanov while (nr > 0) { 17174bd59bbSPavel Emelyanov kill_proc_info(SIGKILL, SEND_SIG_PRIV, nr); 17274bd59bbSPavel Emelyanov nr = next_pidmap(pid_ns, nr); 17374bd59bbSPavel Emelyanov } 17474bd59bbSPavel Emelyanov read_unlock(&tasklist_lock); 17574bd59bbSPavel Emelyanov 17674bd59bbSPavel Emelyanov do { 17774bd59bbSPavel Emelyanov clear_thread_flag(TIF_SIGPENDING); 17874bd59bbSPavel Emelyanov rc = sys_wait4(-1, NULL, __WALL, NULL); 17974bd59bbSPavel Emelyanov } while (rc != -ECHILD); 18074bd59bbSPavel Emelyanov 18174bd59bbSPavel Emelyanov 18274bd59bbSPavel Emelyanov /* Child reaper for the pid namespace is going away */ 18374bd59bbSPavel Emelyanov pid_ns->child_reaper = NULL; 18474bd59bbSPavel Emelyanov return; 18574bd59bbSPavel Emelyanov } 18674bd59bbSPavel Emelyanov 18774bd59bbSPavel Emelyanov static __init int pid_namespaces_init(void) 18874bd59bbSPavel Emelyanov { 18974bd59bbSPavel Emelyanov pid_ns_cachep = KMEM_CACHE(pid_namespace, SLAB_PANIC); 19074bd59bbSPavel Emelyanov return 0; 19174bd59bbSPavel Emelyanov } 19274bd59bbSPavel Emelyanov 19374bd59bbSPavel Emelyanov __initcall(pid_namespaces_init); 194