Pavel Emelyanov | 74bd59b | 2008-02-08 04:18:24 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Pid namespaces |
| 3 | * |
| 4 | * Authors: |
| 5 | * (C) 2007 Pavel Emelyanov <xemul@openvz.org>, OpenVZ, SWsoft Inc. |
| 6 | * (C) 2007 Sukadev Bhattiprolu <sukadev@us.ibm.com>, IBM |
| 7 | * Many thanks to Oleg Nesterov for comments and help |
| 8 | * |
| 9 | */ |
| 10 | |
| 11 | #include <linux/pid.h> |
| 12 | #include <linux/pid_namespace.h> |
| 13 | #include <linux/syscalls.h> |
| 14 | #include <linux/err.h> |
Pavel Emelyanov | 0b6b030 | 2008-07-25 01:48:47 -0700 | [diff] [blame] | 15 | #include <linux/acct.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 16 | #include <linux/slab.h> |
Pavel Emelyanov | 74bd59b | 2008-02-08 04:18:24 -0800 | [diff] [blame] | 17 | |
| 18 | #define BITS_PER_PAGE (PAGE_SIZE*8) |
| 19 | |
| 20 | struct pid_cache { |
| 21 | int nr_ids; |
| 22 | char name[16]; |
| 23 | struct kmem_cache *cachep; |
| 24 | struct list_head list; |
| 25 | }; |
| 26 | |
| 27 | static LIST_HEAD(pid_caches_lh); |
| 28 | static DEFINE_MUTEX(pid_caches_mutex); |
| 29 | static struct kmem_cache *pid_ns_cachep; |
| 30 | |
| 31 | /* |
| 32 | * creates the kmem cache to allocate pids from. |
| 33 | * @nr_ids: the number of numerical ids this pid will have to carry |
| 34 | */ |
| 35 | |
| 36 | static struct kmem_cache *create_pid_cachep(int nr_ids) |
| 37 | { |
| 38 | struct pid_cache *pcache; |
| 39 | struct kmem_cache *cachep; |
| 40 | |
| 41 | mutex_lock(&pid_caches_mutex); |
| 42 | list_for_each_entry(pcache, &pid_caches_lh, list) |
| 43 | if (pcache->nr_ids == nr_ids) |
| 44 | goto out; |
| 45 | |
| 46 | pcache = kmalloc(sizeof(struct pid_cache), GFP_KERNEL); |
| 47 | if (pcache == NULL) |
| 48 | goto err_alloc; |
| 49 | |
| 50 | snprintf(pcache->name, sizeof(pcache->name), "pid_%d", nr_ids); |
| 51 | cachep = kmem_cache_create(pcache->name, |
| 52 | sizeof(struct pid) + (nr_ids - 1) * sizeof(struct upid), |
| 53 | 0, SLAB_HWCACHE_ALIGN, NULL); |
| 54 | if (cachep == NULL) |
| 55 | goto err_cachep; |
| 56 | |
| 57 | pcache->nr_ids = nr_ids; |
| 58 | pcache->cachep = cachep; |
| 59 | list_add(&pcache->list, &pid_caches_lh); |
| 60 | out: |
| 61 | mutex_unlock(&pid_caches_mutex); |
| 62 | return pcache->cachep; |
| 63 | |
| 64 | err_cachep: |
| 65 | kfree(pcache); |
| 66 | err_alloc: |
| 67 | mutex_unlock(&pid_caches_mutex); |
| 68 | return NULL; |
| 69 | } |
| 70 | |
Alexey Dobriyan | ed469a6 | 2009-06-17 16:27:52 -0700 | [diff] [blame] | 71 | static struct pid_namespace *create_pid_namespace(struct pid_namespace *parent_pid_ns) |
Pavel Emelyanov | 74bd59b | 2008-02-08 04:18:24 -0800 | [diff] [blame] | 72 | { |
| 73 | struct pid_namespace *ns; |
Alexey Dobriyan | ed469a6 | 2009-06-17 16:27:52 -0700 | [diff] [blame] | 74 | unsigned int level = parent_pid_ns->level + 1; |
Pavel Emelyanov | 74bd59b | 2008-02-08 04:18:24 -0800 | [diff] [blame] | 75 | int i; |
| 76 | |
Pavel Emelyanov | 84406c1 | 2008-07-25 01:48:42 -0700 | [diff] [blame] | 77 | ns = kmem_cache_zalloc(pid_ns_cachep, GFP_KERNEL); |
Pavel Emelyanov | 74bd59b | 2008-02-08 04:18:24 -0800 | [diff] [blame] | 78 | if (ns == NULL) |
| 79 | goto out; |
| 80 | |
| 81 | ns->pidmap[0].page = kzalloc(PAGE_SIZE, GFP_KERNEL); |
| 82 | if (!ns->pidmap[0].page) |
| 83 | goto out_free; |
| 84 | |
| 85 | ns->pid_cachep = create_pid_cachep(level + 1); |
| 86 | if (ns->pid_cachep == NULL) |
| 87 | goto out_free_map; |
| 88 | |
| 89 | kref_init(&ns->kref); |
Pavel Emelyanov | 74bd59b | 2008-02-08 04:18:24 -0800 | [diff] [blame] | 90 | ns->level = level; |
Alexey Dobriyan | ed469a6 | 2009-06-17 16:27:52 -0700 | [diff] [blame] | 91 | ns->parent = get_pid_ns(parent_pid_ns); |
Pavel Emelyanov | 74bd59b | 2008-02-08 04:18:24 -0800 | [diff] [blame] | 92 | |
| 93 | set_bit(0, ns->pidmap[0].page); |
| 94 | atomic_set(&ns->pidmap[0].nr_free, BITS_PER_PAGE - 1); |
| 95 | |
Pavel Emelyanov | 84406c1 | 2008-07-25 01:48:42 -0700 | [diff] [blame] | 96 | for (i = 1; i < PIDMAP_ENTRIES; i++) |
Pavel Emelyanov | 74bd59b | 2008-02-08 04:18:24 -0800 | [diff] [blame] | 97 | atomic_set(&ns->pidmap[i].nr_free, BITS_PER_PAGE); |
Pavel Emelyanov | 74bd59b | 2008-02-08 04:18:24 -0800 | [diff] [blame] | 98 | |
| 99 | return ns; |
| 100 | |
| 101 | out_free_map: |
| 102 | kfree(ns->pidmap[0].page); |
| 103 | out_free: |
| 104 | kmem_cache_free(pid_ns_cachep, ns); |
| 105 | out: |
| 106 | return ERR_PTR(-ENOMEM); |
| 107 | } |
| 108 | |
| 109 | static void destroy_pid_namespace(struct pid_namespace *ns) |
| 110 | { |
| 111 | int i; |
| 112 | |
| 113 | for (i = 0; i < PIDMAP_ENTRIES; i++) |
| 114 | kfree(ns->pidmap[i].page); |
| 115 | kmem_cache_free(pid_ns_cachep, ns); |
| 116 | } |
| 117 | |
| 118 | struct pid_namespace *copy_pid_ns(unsigned long flags, struct pid_namespace *old_ns) |
| 119 | { |
Pavel Emelyanov | 74bd59b | 2008-02-08 04:18:24 -0800 | [diff] [blame] | 120 | if (!(flags & CLONE_NEWPID)) |
Alexey Dobriyan | dca4a97 | 2009-06-17 16:27:53 -0700 | [diff] [blame] | 121 | return get_pid_ns(old_ns); |
Sukadev Bhattiprolu | e5a4738 | 2009-09-23 15:57:22 -0700 | [diff] [blame] | 122 | if (flags & (CLONE_THREAD|CLONE_PARENT)) |
Alexey Dobriyan | dca4a97 | 2009-06-17 16:27:53 -0700 | [diff] [blame] | 123 | return ERR_PTR(-EINVAL); |
| 124 | return create_pid_namespace(old_ns); |
Pavel Emelyanov | 74bd59b | 2008-02-08 04:18:24 -0800 | [diff] [blame] | 125 | } |
| 126 | |
| 127 | void free_pid_ns(struct kref *kref) |
| 128 | { |
| 129 | struct pid_namespace *ns, *parent; |
| 130 | |
| 131 | ns = container_of(kref, struct pid_namespace, kref); |
| 132 | |
| 133 | parent = ns->parent; |
| 134 | destroy_pid_namespace(ns); |
| 135 | |
| 136 | if (parent != NULL) |
| 137 | put_pid_ns(parent); |
| 138 | } |
| 139 | |
| 140 | void zap_pid_ns_processes(struct pid_namespace *pid_ns) |
| 141 | { |
| 142 | int nr; |
| 143 | int rc; |
Sukadev Bhattiprolu | e4da026 | 2009-04-02 16:58:06 -0700 | [diff] [blame] | 144 | struct task_struct *task; |
Pavel Emelyanov | 74bd59b | 2008-02-08 04:18:24 -0800 | [diff] [blame] | 145 | |
| 146 | /* |
| 147 | * The last thread in the cgroup-init thread group is terminating. |
| 148 | * Find remaining pid_ts in the namespace, signal and wait for them |
| 149 | * to exit. |
| 150 | * |
| 151 | * Note: This signals each threads in the namespace - even those that |
| 152 | * belong to the same thread group, To avoid this, we would have |
| 153 | * to walk the entire tasklist looking a processes in this |
| 154 | * namespace, but that could be unnecessarily expensive if the |
| 155 | * pid namespace has just a few processes. Or we need to |
| 156 | * maintain a tasklist for each pid namespace. |
| 157 | * |
| 158 | */ |
| 159 | read_lock(&tasklist_lock); |
| 160 | nr = next_pidmap(pid_ns, 1); |
| 161 | while (nr > 0) { |
Sukadev Bhattiprolu | e4da026 | 2009-04-02 16:58:06 -0700 | [diff] [blame] | 162 | rcu_read_lock(); |
| 163 | |
| 164 | /* |
Oleg Nesterov | 13aa9a6 | 2010-03-10 15:23:09 -0800 | [diff] [blame] | 165 | * Any nested-container's init processes won't ignore the |
| 166 | * SEND_SIG_NOINFO signal, see send_signal()->si_fromuser(). |
Sukadev Bhattiprolu | e4da026 | 2009-04-02 16:58:06 -0700 | [diff] [blame] | 167 | */ |
| 168 | task = pid_task(find_vpid(nr), PIDTYPE_PID); |
| 169 | if (task) |
Oleg Nesterov | 13aa9a6 | 2010-03-10 15:23:09 -0800 | [diff] [blame] | 170 | send_sig_info(SIGKILL, SEND_SIG_NOINFO, task); |
Sukadev Bhattiprolu | e4da026 | 2009-04-02 16:58:06 -0700 | [diff] [blame] | 171 | |
| 172 | rcu_read_unlock(); |
| 173 | |
Pavel Emelyanov | 74bd59b | 2008-02-08 04:18:24 -0800 | [diff] [blame] | 174 | nr = next_pidmap(pid_ns, nr); |
| 175 | } |
| 176 | read_unlock(&tasklist_lock); |
| 177 | |
| 178 | do { |
| 179 | clear_thread_flag(TIF_SIGPENDING); |
| 180 | rc = sys_wait4(-1, NULL, __WALL, NULL); |
| 181 | } while (rc != -ECHILD); |
| 182 | |
Pavel Emelyanov | 0b6b030 | 2008-07-25 01:48:47 -0700 | [diff] [blame] | 183 | acct_exit_ns(pid_ns); |
Pavel Emelyanov | 74bd59b | 2008-02-08 04:18:24 -0800 | [diff] [blame] | 184 | return; |
| 185 | } |
| 186 | |
| 187 | static __init int pid_namespaces_init(void) |
| 188 | { |
| 189 | pid_ns_cachep = KMEM_CACHE(pid_namespace, SLAB_PANIC); |
| 190 | return 0; |
| 191 | } |
| 192 | |
| 193 | __initcall(pid_namespaces_init); |