* allocation scenario when all but one out of 1 million PIDs possible are
* allocated already: the scanning of 32 list entries and at most PAGE_SIZE
* bytes. The typical fastpath is a single successful setbit. Freeing is O(1).
+ *
+ * Pid namespaces:
+ * (C) 2007 Pavel Emelyanov <xemul@openvz.org>, OpenVZ, SWsoft Inc.
+ * (C) 2007 Sukadev Bhattiprolu <sukadev@us.ibm.com>, IBM
+ * Many thanks to Oleg Nesterov for comments and help
+ *
*/
#include <linux/mm.h>
#include <linux/hash.h>
#include <linux/pid_namespace.h>
#include <linux/init_task.h>
+#include <linux/syscalls.h>
-#define pid_hashfn(nr) hash_long((unsigned long)nr, pidhash_shift)
+#define pid_hashfn(nr, ns) \
+ hash_long((unsigned long)nr + (unsigned long)ns, pidhash_shift)
static struct hlist_head *pid_hash;
static int pidhash_shift;
-static struct kmem_cache *pid_cachep;
struct pid init_struct_pid = INIT_STRUCT_PID;
+static struct kmem_cache *pid_ns_cachep;
int pid_max = PID_MAX_DEFAULT;
[ 0 ... PIDMAP_ENTRIES-1] = { ATOMIC_INIT(BITS_PER_PAGE), NULL }
},
.last_pid = 0,
- .child_reaper = &init_task
+ .level = 0,
+ .child_reaper = &init_task,
};
+EXPORT_SYMBOL_GPL(init_pid_ns);
+
+int is_container_init(struct task_struct *tsk)
+{
+ int ret = 0;
+ struct pid *pid;
+
+ rcu_read_lock();
+ pid = task_pid(tsk);
+ if (pid != NULL && pid->numbers[pid->level].nr == 1)
+ ret = 1;
+ rcu_read_unlock();
+
+ return ret;
+}
+EXPORT_SYMBOL(is_container_init);
/*
* Note: disable interrupts while the pidmap_lock is held as an
fastcall void put_pid(struct pid *pid)
{
+ struct pid_namespace *ns;
+
if (!pid)
return;
+
+ ns = pid->numbers[pid->level].ns;
if ((atomic_read(&pid->count) == 1) ||
- atomic_dec_and_test(&pid->count))
- kmem_cache_free(pid_cachep, pid);
+ atomic_dec_and_test(&pid->count)) {
+ kmem_cache_free(ns->pid_cachep, pid);
+ put_pid_ns(ns);
+ }
}
EXPORT_SYMBOL_GPL(put_pid);
fastcall void free_pid(struct pid *pid)
{
/* We can be called with write_lock_irq(&tasklist_lock) held */
+ int i;
unsigned long flags;
spin_lock_irqsave(&pidmap_lock, flags);
- hlist_del_rcu(&pid->pid_chain);
+ for (i = 0; i <= pid->level; i++)
+ hlist_del_rcu(&pid->numbers[i].pid_chain);
spin_unlock_irqrestore(&pidmap_lock, flags);
- free_pidmap(&init_pid_ns, pid->nr);
+ for (i = 0; i <= pid->level; i++)
+ free_pidmap(pid->numbers[i].ns, pid->numbers[i].nr);
+
call_rcu(&pid->rcu, delayed_put_pid);
}
-struct pid *alloc_pid(void)
+struct pid *alloc_pid(struct pid_namespace *ns)
{
struct pid *pid;
enum pid_type type;
- int nr = -1;
+ int i, nr;
+ struct pid_namespace *tmp;
+ struct upid *upid;
- pid = kmem_cache_alloc(pid_cachep, GFP_KERNEL);
+ pid = kmem_cache_alloc(ns->pid_cachep, GFP_KERNEL);
if (!pid)
goto out;
- nr = alloc_pidmap(current->nsproxy->pid_ns);
- if (nr < 0)
- goto out_free;
+ tmp = ns;
+ for (i = ns->level; i >= 0; i--) {
+ nr = alloc_pidmap(tmp);
+ if (nr < 0)
+ goto out_free;
+
+ pid->numbers[i].nr = nr;
+ pid->numbers[i].ns = tmp;
+ tmp = tmp->parent;
+ }
+ get_pid_ns(ns);
+ pid->level = ns->level;
atomic_set(&pid->count, 1);
- pid->nr = nr;
for (type = 0; type < PIDTYPE_MAX; ++type)
INIT_HLIST_HEAD(&pid->tasks[type]);
spin_lock_irq(&pidmap_lock);
- hlist_add_head_rcu(&pid->pid_chain, &pid_hash[pid_hashfn(pid->nr)]);
+ for (i = ns->level; i >= 0; i--) {
+ upid = &pid->numbers[i];
+ hlist_add_head_rcu(&upid->pid_chain,
+ &pid_hash[pid_hashfn(upid->nr, upid->ns)]);
+ }
spin_unlock_irq(&pidmap_lock);
out:
return pid;
out_free:
- kmem_cache_free(pid_cachep, pid);
+ for (i++; i <= ns->level; i++)
+ free_pidmap(pid->numbers[i].ns, pid->numbers[i].nr);
+
+ kmem_cache_free(ns->pid_cachep, pid);
pid = NULL;
goto out;
}
-struct pid * fastcall find_pid(int nr)
+struct pid * fastcall find_pid_ns(int nr, struct pid_namespace *ns)
{
struct hlist_node *elem;
- struct pid *pid;
+ struct upid *pnr;
+
+ hlist_for_each_entry_rcu(pnr, elem,
+ &pid_hash[pid_hashfn(nr, ns)], pid_chain)
+ if (pnr->nr == nr && pnr->ns == ns)
+ return container_of(pnr, struct pid,
+ numbers[ns->level]);
- hlist_for_each_entry_rcu(pid, elem,
- &pid_hash[pid_hashfn(nr)], pid_chain) {
- if (pid->nr == nr)
- return pid;
- }
return NULL;
}
+EXPORT_SYMBOL_GPL(find_pid_ns);
+
+struct pid *find_vpid(int nr)
+{
+ return find_pid_ns(nr, current->nsproxy->pid_ns);
+}
+EXPORT_SYMBOL_GPL(find_vpid);
+
+struct pid *find_pid(int nr)
+{
+ return find_pid_ns(nr, &init_pid_ns);
+}
EXPORT_SYMBOL_GPL(find_pid);
/*
/*
* Must be called under rcu_read_lock() or with tasklist_lock read-held.
*/
-struct task_struct *find_task_by_pid_type(int type, int nr)
+struct task_struct *find_task_by_pid_type_ns(int type, int nr,
+ struct pid_namespace *ns)
{
- return pid_task(find_pid(nr), type);
+ return pid_task(find_pid_ns(nr, ns), type);
}
-EXPORT_SYMBOL(find_task_by_pid_type);
+EXPORT_SYMBOL(find_task_by_pid_type_ns);
+
+struct task_struct *find_task_by_pid(pid_t nr)
+{
+ return find_task_by_pid_type_ns(PIDTYPE_PID, nr, &init_pid_ns);
+}
+EXPORT_SYMBOL(find_task_by_pid);
+
+struct task_struct *find_task_by_vpid(pid_t vnr)
+{
+ return find_task_by_pid_type_ns(PIDTYPE_PID, vnr,
+ current->nsproxy->pid_ns);
+}
+EXPORT_SYMBOL(find_task_by_vpid);
+
+struct task_struct *find_task_by_pid_ns(pid_t nr, struct pid_namespace *ns)
+{
+ return find_task_by_pid_type_ns(PIDTYPE_PID, nr, ns);
+}
+EXPORT_SYMBOL(find_task_by_pid_ns);
struct pid *get_task_pid(struct task_struct *task, enum pid_type type)
{
struct pid *pid;
rcu_read_lock();
- pid = get_pid(find_pid(nr));
+ pid = get_pid(find_vpid(nr));
rcu_read_unlock();
return pid;
}
+pid_t pid_nr_ns(struct pid *pid, struct pid_namespace *ns)
+{
+ struct upid *upid;
+ pid_t nr = 0;
+
+ if (pid && ns->level <= pid->level) {
+ upid = &pid->numbers[ns->level];
+ if (upid->ns == ns)
+ nr = upid->nr;
+ }
+ return nr;
+}
+
+pid_t task_pid_nr_ns(struct task_struct *tsk, struct pid_namespace *ns)
+{
+ return pid_nr_ns(task_pid(tsk), ns);
+}
+EXPORT_SYMBOL(task_pid_nr_ns);
+
+pid_t task_tgid_nr_ns(struct task_struct *tsk, struct pid_namespace *ns)
+{
+ return pid_nr_ns(task_tgid(tsk), ns);
+}
+EXPORT_SYMBOL(task_tgid_nr_ns);
+
+pid_t task_pgrp_nr_ns(struct task_struct *tsk, struct pid_namespace *ns)
+{
+ return pid_nr_ns(task_pgrp(tsk), ns);
+}
+EXPORT_SYMBOL(task_pgrp_nr_ns);
+
+pid_t task_session_nr_ns(struct task_struct *tsk, struct pid_namespace *ns)
+{
+ return pid_nr_ns(task_session(tsk), ns);
+}
+EXPORT_SYMBOL(task_session_nr_ns);
+
/*
* Used by proc to find the first pid that is greater then or equal to nr.
*
* If there is a pid at nr this function is exactly the same as find_pid.
*/
-struct pid *find_ge_pid(int nr)
+struct pid *find_ge_pid(int nr, struct pid_namespace *ns)
{
struct pid *pid;
do {
- pid = find_pid(nr);
+ pid = find_pid_ns(nr, ns);
if (pid)
break;
- nr = next_pidmap(current->nsproxy->pid_ns, nr);
+ nr = next_pidmap(ns, nr);
} while (nr > 0);
return pid;
}
EXPORT_SYMBOL_GPL(find_get_pid);
+struct pid_cache {
+ int nr_ids;
+ char name[16];
+ struct kmem_cache *cachep;
+ struct list_head list;
+};
+
+static LIST_HEAD(pid_caches_lh);
+static DEFINE_MUTEX(pid_caches_mutex);
+
+/*
+ * creates the kmem cache to allocate pids from.
+ * @nr_ids: the number of numerical ids this pid will have to carry
+ */
+
+static struct kmem_cache *create_pid_cachep(int nr_ids)
+{
+ struct pid_cache *pcache;
+ struct kmem_cache *cachep;
+
+ mutex_lock(&pid_caches_mutex);
+ list_for_each_entry (pcache, &pid_caches_lh, list)
+ if (pcache->nr_ids == nr_ids)
+ goto out;
+
+ pcache = kmalloc(sizeof(struct pid_cache), GFP_KERNEL);
+ if (pcache == NULL)
+ goto err_alloc;
+
+ snprintf(pcache->name, sizeof(pcache->name), "pid_%d", nr_ids);
+ cachep = kmem_cache_create(pcache->name,
+ sizeof(struct pid) + (nr_ids - 1) * sizeof(struct upid),
+ 0, SLAB_HWCACHE_ALIGN, NULL);
+ if (cachep == NULL)
+ goto err_cachep;
+
+ pcache->nr_ids = nr_ids;
+ pcache->cachep = cachep;
+ list_add(&pcache->list, &pid_caches_lh);
+out:
+ mutex_unlock(&pid_caches_mutex);
+ return pcache->cachep;
+
+err_cachep:
+ kfree(pcache);
+err_alloc:
+ mutex_unlock(&pid_caches_mutex);
+ return NULL;
+}
+
+#ifdef CONFIG_PID_NS
+static struct pid_namespace *create_pid_namespace(int level)
+{
+ struct pid_namespace *ns;
+ int i;
+
+ ns = kmem_cache_alloc(pid_ns_cachep, GFP_KERNEL);
+ if (ns == NULL)
+ goto out;
+
+ ns->pidmap[0].page = kzalloc(PAGE_SIZE, GFP_KERNEL);
+ if (!ns->pidmap[0].page)
+ goto out_free;
+
+ ns->pid_cachep = create_pid_cachep(level + 1);
+ if (ns->pid_cachep == NULL)
+ goto out_free_map;
+
+ kref_init(&ns->kref);
+ ns->last_pid = 0;
+ ns->child_reaper = NULL;
+ ns->level = level;
+
+ set_bit(0, ns->pidmap[0].page);
+ atomic_set(&ns->pidmap[0].nr_free, BITS_PER_PAGE - 1);
+
+ for (i = 1; i < PIDMAP_ENTRIES; i++) {
+ ns->pidmap[i].page = 0;
+ atomic_set(&ns->pidmap[i].nr_free, BITS_PER_PAGE);
+ }
+
+ return ns;
+
+out_free_map:
+ kfree(ns->pidmap[0].page);
+out_free:
+ kmem_cache_free(pid_ns_cachep, ns);
+out:
+ return ERR_PTR(-ENOMEM);
+}
+
+static void destroy_pid_namespace(struct pid_namespace *ns)
+{
+ int i;
+
+ for (i = 0; i < PIDMAP_ENTRIES; i++)
+ kfree(ns->pidmap[i].page);
+ kmem_cache_free(pid_ns_cachep, ns);
+}
+
struct pid_namespace *copy_pid_ns(unsigned long flags, struct pid_namespace *old_ns)
{
+ struct pid_namespace *new_ns;
+
BUG_ON(!old_ns);
- get_pid_ns(old_ns);
- return old_ns;
+ new_ns = get_pid_ns(old_ns);
+ if (!(flags & CLONE_NEWPID))
+ goto out;
+
+ new_ns = ERR_PTR(-EINVAL);
+ if (flags & CLONE_THREAD)
+ goto out_put;
+
+ new_ns = create_pid_namespace(old_ns->level + 1);
+ if (!IS_ERR(new_ns))
+ new_ns->parent = get_pid_ns(old_ns);
+
+out_put:
+ put_pid_ns(old_ns);
+out:
+ return new_ns;
}
void free_pid_ns(struct kref *kref)
{
- struct pid_namespace *ns;
+ struct pid_namespace *ns, *parent;
ns = container_of(kref, struct pid_namespace, kref);
- kfree(ns);
+
+ parent = ns->parent;
+ destroy_pid_namespace(ns);
+
+ if (parent != NULL)
+ put_pid_ns(parent);
+}
+#endif /* CONFIG_PID_NS */
+
+void zap_pid_ns_processes(struct pid_namespace *pid_ns)
+{
+ int nr;
+ int rc;
+
+ /*
+ * The last thread in the cgroup-init thread group is terminating.
+ * Find remaining pid_ts in the namespace, signal and wait for them
+ * to exit.
+ *
+ * Note: This signals each threads in the namespace - even those that
+ * belong to the same thread group, To avoid this, we would have
+ * to walk the entire tasklist looking a processes in this
+ * namespace, but that could be unnecessarily expensive if the
+ * pid namespace has just a few processes. Or we need to
+ * maintain a tasklist for each pid namespace.
+ *
+ */
+ read_lock(&tasklist_lock);
+ nr = next_pidmap(pid_ns, 1);
+ while (nr > 0) {
+ kill_proc_info(SIGKILL, SEND_SIG_PRIV, nr);
+ nr = next_pidmap(pid_ns, nr);
+ }
+ read_unlock(&tasklist_lock);
+
+ do {
+ clear_thread_flag(TIF_SIGPENDING);
+ rc = sys_wait4(-1, NULL, __WALL, NULL);
+ } while (rc != -ECHILD);
+
+
+ /* Child reaper for the pid namespace is going away */
+ pid_ns->child_reaper = NULL;
+ return;
}
/*
set_bit(0, init_pid_ns.pidmap[0].page);
atomic_dec(&init_pid_ns.pidmap[0].nr_free);
- pid_cachep = KMEM_CACHE(pid, SLAB_PANIC);
+ init_pid_ns.pid_cachep = create_pid_cachep(1);
+ if (init_pid_ns.pid_cachep == NULL)
+ panic("Can't create pid_1 cachep\n");
+
+ pid_ns_cachep = KMEM_CACHE(pid_namespace, SLAB_PANIC);
}
git.openpandora.org / pandora-kernel.git / blobdiff