#include <linux/bitops.h>
#include <linux/key.h>
#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/user_namespace.h>
/*
* UID task count cache, to get fast user lookup in "alloc_uid"
* when changing user ID's (ie setuid() and friends).
*/
-#define UIDHASH_BITS (CONFIG_BASE_SMALL ? 3 : 8)
-#define UIDHASH_SZ (1 << UIDHASH_BITS)
#define UIDHASH_MASK (UIDHASH_SZ - 1)
#define __uidhashfn(uid) (((uid >> UIDHASH_BITS) + uid) & UIDHASH_MASK)
-#define uidhashentry(uid) (uidhash_table + __uidhashfn((uid)))
+#define uidhashentry(ns, uid) ((ns)->uidhash_table + __uidhashfn((uid)))
static struct kmem_cache *uid_cachep;
-static struct list_head uidhash_table[UIDHASH_SZ];
/*
* The uidhash_lock is mostly taken from process context, but it is
.uid_keyring = &root_user_keyring,
.session_keyring = &root_session_keyring,
#endif
+#ifdef CONFIG_FAIR_USER_SCHED
+ .tg = &init_task_group,
+#endif
};
/*
* These routines must be called with the uidhash spinlock held!
*/
-static inline void uid_hash_insert(struct user_struct *up, struct list_head *hashent)
+static inline void uid_hash_insert(struct user_struct *up,
+ struct hlist_head *hashent)
{
- list_add(&up->uidhash_list, hashent);
+ hlist_add_head(&up->uidhash_node, hashent);
}
static inline void uid_hash_remove(struct user_struct *up)
{
- list_del(&up->uidhash_list);
+ hlist_del_init(&up->uidhash_node);
}
-static inline struct user_struct *uid_hash_find(uid_t uid, struct list_head *hashent)
+static inline struct user_struct *uid_hash_find(uid_t uid,
+ struct hlist_head *hashent)
{
- struct list_head *up;
-
- list_for_each(up, hashent) {
- struct user_struct *user;
+ struct user_struct *user;
+ struct hlist_node *h;
- user = list_entry(up, struct user_struct, uidhash_list);
-
- if(user->uid == uid) {
+ hlist_for_each_entry(user, h, hashent, uidhash_node) {
+ if (user->uid == uid) {
atomic_inc(&user->__count);
return user;
}
return NULL;
}
+#ifdef CONFIG_FAIR_USER_SCHED
+
+static struct kobject uids_kobject; /* represents /sys/kernel/uids directory */
+static DEFINE_MUTEX(uids_mutex);
+
+static void sched_destroy_user(struct user_struct *up)
+{
+ sched_destroy_group(up->tg);
+}
+
+static int sched_create_user(struct user_struct *up)
+{
+ int rc = 0;
+
+ up->tg = sched_create_group();
+ if (IS_ERR(up->tg))
+ rc = -ENOMEM;
+
+ return rc;
+}
+
+static void sched_switch_user(struct task_struct *p)
+{
+ sched_move_task(p);
+}
+
+static inline void uids_mutex_lock(void)
+{
+ mutex_lock(&uids_mutex);
+}
+
+static inline void uids_mutex_unlock(void)
+{
+ mutex_unlock(&uids_mutex);
+}
+
+/* return cpu shares held by the user */
+ssize_t cpu_shares_show(struct kset *kset, char *buffer)
+{
+ struct user_struct *up = container_of(kset, struct user_struct, kset);
+
+ return sprintf(buffer, "%lu\n", sched_group_shares(up->tg));
+}
+
+/* modify cpu shares held by the user */
+ssize_t cpu_shares_store(struct kset *kset, const char *buffer, size_t size)
+{
+ struct user_struct *up = container_of(kset, struct user_struct, kset);
+ unsigned long shares;
+ int rc;
+
+ sscanf(buffer, "%lu", &shares);
+
+ rc = sched_group_set_shares(up->tg, shares);
+
+ return (rc ? rc : size);
+}
+
+static void user_attr_init(struct subsys_attribute *sa, char *name, int mode)
+{
+ sa->attr.name = name;
+ sa->attr.mode = mode;
+ sa->show = cpu_shares_show;
+ sa->store = cpu_shares_store;
+}
+
+/* Create "/sys/kernel/uids/<uid>" directory and
+ * "/sys/kernel/uids/<uid>/cpu_share" file for this user.
+ */
+static int user_kobject_create(struct user_struct *up)
+{
+ struct kset *kset = &up->kset;
+ struct kobject *kobj = &kset->kobj;
+ int error;
+
+ memset(kset, 0, sizeof(struct kset));
+ kobj->parent = &uids_kobject; /* create under /sys/kernel/uids dir */
+ kobject_set_name(kobj, "%d", up->uid);
+ kset_init(kset);
+ user_attr_init(&up->user_attr, "cpu_share", 0644);
+
+ error = kobject_add(kobj);
+ if (error)
+ goto done;
+
+ error = sysfs_create_file(kobj, &up->user_attr.attr);
+ if (error)
+ kobject_del(kobj);
+
+ kobject_uevent(kobj, KOBJ_ADD);
+
+done:
+ return error;
+}
+
+/* create these in sysfs filesystem:
+ * "/sys/kernel/uids" directory
+ * "/sys/kernel/uids/0" directory (for root user)
+ * "/sys/kernel/uids/0/cpu_share" file (for root user)
+ */
+int __init uids_kobject_init(void)
+{
+ int error;
+
+ /* create under /sys/kernel dir */
+ uids_kobject.parent = &kernel_subsys.kobj;
+ uids_kobject.kset = &kernel_subsys;
+ kobject_set_name(&uids_kobject, "uids");
+ kobject_init(&uids_kobject);
+
+ error = kobject_add(&uids_kobject);
+ if (!error)
+ error = user_kobject_create(&root_user);
+
+ return error;
+}
+
+/* work function to remove sysfs directory for a user and free up
+ * corresponding structures.
+ */
+static void remove_user_sysfs_dir(struct work_struct *w)
+{
+ struct user_struct *up = container_of(w, struct user_struct, work);
+ struct kobject *kobj = &up->kset.kobj;
+ unsigned long flags;
+ int remove_user = 0;
+
+ /* Make uid_hash_remove() + sysfs_remove_file() + kobject_del()
+ * atomic.
+ */
+ uids_mutex_lock();
+
+ local_irq_save(flags);
+
+ if (atomic_dec_and_lock(&up->__count, &uidhash_lock)) {
+ uid_hash_remove(up);
+ remove_user = 1;
+ spin_unlock_irqrestore(&uidhash_lock, flags);
+ } else {
+ local_irq_restore(flags);
+ }
+
+ if (!remove_user)
+ goto done;
+
+ sysfs_remove_file(kobj, &up->user_attr.attr);
+ kobject_uevent(kobj, KOBJ_REMOVE);
+ kobject_del(kobj);
+
+ sched_destroy_user(up);
+ key_put(up->uid_keyring);
+ key_put(up->session_keyring);
+ kmem_cache_free(uid_cachep, up);
+
+done:
+ uids_mutex_unlock();
+}
+
+/* IRQs are disabled and uidhash_lock is held upon function entry.
+ * IRQ state (as stored in flags) is restored and uidhash_lock released
+ * upon function exit.
+ */
+static inline void free_user(struct user_struct *up, unsigned long flags)
+{
+ /* restore back the count */
+ atomic_inc(&up->__count);
+ spin_unlock_irqrestore(&uidhash_lock, flags);
+
+ INIT_WORK(&up->work, remove_user_sysfs_dir);
+ schedule_work(&up->work);
+}
+
+#else /* CONFIG_FAIR_USER_SCHED */
+
+static void sched_destroy_user(struct user_struct *up) { }
+static int sched_create_user(struct user_struct *up) { return 0; }
+static void sched_switch_user(struct task_struct *p) { }
+static inline int user_kobject_create(struct user_struct *up) { return 0; }
+static inline void uids_mutex_lock(void) { }
+static inline void uids_mutex_unlock(void) { }
+
+/* IRQs are disabled and uidhash_lock is held upon function entry.
+ * IRQ state (as stored in flags) is restored and uidhash_lock released
+ * upon function exit.
+ */
+static inline void free_user(struct user_struct *up, unsigned long flags)
+{
+ uid_hash_remove(up);
+ spin_unlock_irqrestore(&uidhash_lock, flags);
+ sched_destroy_user(up);
+ key_put(up->uid_keyring);
+ key_put(up->session_keyring);
+ kmem_cache_free(uid_cachep, up);
+}
+
+#endif /* CONFIG_FAIR_USER_SCHED */
+
/*
* Locate the user_struct for the passed UID. If found, take a ref on it. The
* caller must undo that ref with free_uid().
{
struct user_struct *ret;
unsigned long flags;
+ struct user_namespace *ns = current->nsproxy->user_ns;
spin_lock_irqsave(&uidhash_lock, flags);
- ret = uid_hash_find(uid, uidhashentry(uid));
+ ret = uid_hash_find(uid, uidhashentry(ns, uid));
spin_unlock_irqrestore(&uidhash_lock, flags);
return ret;
}
return;
local_irq_save(flags);
- if (atomic_dec_and_lock(&up->__count, &uidhash_lock)) {
- uid_hash_remove(up);
- spin_unlock_irqrestore(&uidhash_lock, flags);
- key_put(up->uid_keyring);
- key_put(up->session_keyring);
- kmem_cache_free(uid_cachep, up);
- } else {
+ if (atomic_dec_and_lock(&up->__count, &uidhash_lock))
+ free_user(up, flags);
+ else
local_irq_restore(flags);
- }
}
-struct user_struct * alloc_uid(uid_t uid)
+struct user_struct * alloc_uid(struct user_namespace *ns, uid_t uid)
{
- struct list_head *hashent = uidhashentry(uid);
+ struct hlist_head *hashent = uidhashentry(ns, uid);
struct user_struct *up;
+ /* Make uid_hash_find() + user_kobject_create() + uid_hash_insert()
+ * atomic.
+ */
+ uids_mutex_lock();
+
spin_lock_irq(&uidhash_lock);
up = uid_hash_find(uid, hashent);
spin_unlock_irq(&uidhash_lock);
return NULL;
}
+ if (sched_create_user(new) < 0) {
+ key_put(new->uid_keyring);
+ key_put(new->session_keyring);
+ kmem_cache_free(uid_cachep, new);
+ return NULL;
+ }
+
+ if (user_kobject_create(new)) {
+ sched_destroy_user(new);
+ key_put(new->uid_keyring);
+ key_put(new->session_keyring);
+ kmem_cache_free(uid_cachep, new);
+ uids_mutex_unlock();
+ return NULL;
+ }
+
/*
* Before adding this, check whether we raced
* on adding the same user already..
spin_lock_irq(&uidhash_lock);
up = uid_hash_find(uid, hashent);
if (up) {
+ /* This case is not possible when CONFIG_FAIR_USER_SCHED
+ * is defined, since we serialize alloc_uid() using
+ * uids_mutex. Hence no need to call
+ * sched_destroy_user() or remove_user_sysfs_dir().
+ */
key_put(new->uid_keyring);
key_put(new->session_keyring);
kmem_cache_free(uid_cachep, new);
spin_unlock_irq(&uidhash_lock);
}
+
+ uids_mutex_unlock();
+
return up;
}
atomic_dec(&old_user->processes);
switch_uid_keyring(new_user);
current->user = new_user;
+ sched_switch_user(current);
/*
* We need to synchronize with __sigqueue_alloc()
suid_keys(current);
}
+void release_uids(struct user_namespace *ns)
+{
+ int i;
+ unsigned long flags;
+ struct hlist_head *head;
+ struct hlist_node *nd;
+
+ spin_lock_irqsave(&uidhash_lock, flags);
+ /*
+ * collapse the chains so that the user_struct-s will
+ * be still alive, but not in hashes. subsequent free_uid()
+ * will free them.
+ */
+ for (i = 0; i < UIDHASH_SZ; i++) {
+ head = ns->uidhash_table + i;
+ while (!hlist_empty(head)) {
+ nd = head->first;
+ hlist_del_init(nd);
+ }
+ }
+ spin_unlock_irqrestore(&uidhash_lock, flags);
+
+ free_uid(ns->root_user);
+}
static int __init uid_cache_init(void)
{
int n;
uid_cachep = kmem_cache_create("uid_cache", sizeof(struct user_struct),
- 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
+ 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
for(n = 0; n < UIDHASH_SZ; ++n)
- INIT_LIST_HEAD(uidhash_table + n);
+ INIT_HLIST_HEAD(init_user_ns.uidhash_table + n);
/* Insert the root user immediately (init already runs as root) */
spin_lock_irq(&uidhash_lock);
- uid_hash_insert(&root_user, uidhashentry(0));
+ uid_hash_insert(&root_user, uidhashentry(&init_user_ns, 0));
spin_unlock_irq(&uidhash_lock);
return 0;
git.openpandora.org / pandora-kernel.git / blobdiff