1 files changed, 318 insertions, 35 deletions

diff --git a/kernel/pid.c b/kernel/pid.c
index c6e3f9ffff87..d1db36b94674 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -18,6 +18,12 @@
  * 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>
@@ -28,12 +34,14 @@
 #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;
 
@@ -68,8 +76,25 @@ struct pid_namespace init_pid_ns = {
                 [ 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
@@ -176,11 +201,17 @@ static int next_pidmap(struct pid_namespace *pid_ns, int last)
 
 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);
 
@@ -193,60 +224,94 @@ static void delayed_put_pid(struct rcu_head *rhp)
 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);
 
 /*
@@ -307,12 +372,32 @@ struct task_struct * fastcall pid_task(struct pid *pid, enum pid_type type)
 /*
  * 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)
 {
@@ -339,45 +424,239 @@ struct pid *find_get_pid(pid_t nr)
         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;
+}
+
+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);
+}
+
+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;
 }
 
 /*
@@ -412,5 +691,9 @@ void __init pidmap_init(void)
         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);
 }