#include <linux/audit.h>
#include <linux/capability.h>
#include <linux/seq_file.h>
-#include <linux/mutex.h>
+#include <linux/rwsem.h>
#include <linux/nsproxy.h>
+#include <linux/ipc_namespace.h>
#include <asm/uaccess.h>
#include "util.h"
-#define sem_ids(ns) (*((ns)->ids[IPC_SEM_IDS]))
+#define sem_ids(ns) ((ns)->ids[IPC_SEM_IDS])
#define sem_unlock(sma) ipc_unlock(&(sma)->sem_perm)
-#define sem_checkid(ns, sma, semid) \
- ipc_checkid(&sem_ids(ns),&sma->sem_perm,semid)
-#define sem_buildid(ns, id, seq) \
- ipc_buildid(&sem_ids(ns), id, seq)
-
-static struct ipc_ids init_sem_ids;
+#define sem_checkid(sma, semid) ipc_checkid(&sma->sem_perm, semid)
+#define sem_buildid(id, seq) ipc_buildid(id, seq)
static int newary(struct ipc_namespace *, struct ipc_params *);
-static void freeary(struct ipc_namespace *, struct sem_array *);
+static void freeary(struct ipc_namespace *, struct kern_ipc_perm *);
#ifdef CONFIG_PROC_FS
static int sysvipc_sem_proc_show(struct seq_file *s, void *it);
#endif
#define sc_semopm sem_ctls[2]
#define sc_semmni sem_ctls[3]
-static void __sem_init_ns(struct ipc_namespace *ns, struct ipc_ids *ids)
+void sem_init_ns(struct ipc_namespace *ns)
{
- ns->ids[IPC_SEM_IDS] = ids;
ns->sc_semmsl = SEMMSL;
ns->sc_semmns = SEMMNS;
ns->sc_semopm = SEMOPM;
ns->sc_semmni = SEMMNI;
ns->used_sems = 0;
- ipc_init_ids(ids);
-}
-
-int sem_init_ns(struct ipc_namespace *ns)
-{
- struct ipc_ids *ids;
-
- ids = kmalloc(sizeof(struct ipc_ids), GFP_KERNEL);
- if (ids == NULL)
- return -ENOMEM;
-
- __sem_init_ns(ns, ids);
- return 0;
+ ipc_init_ids(&ns->ids[IPC_SEM_IDS]);
}
+#ifdef CONFIG_IPC_NS
void sem_exit_ns(struct ipc_namespace *ns)
{
- struct sem_array *sma;
- int next_id;
- int total, in_use;
-
- mutex_lock(&sem_ids(ns).mutex);
-
- in_use = sem_ids(ns).in_use;
-
- for (total = 0, next_id = 0; total < in_use; next_id++) {
- sma = idr_find(&sem_ids(ns).ipcs_idr, next_id);
- if (sma == NULL)
- continue;
- ipc_lock_by_ptr(&sma->sem_perm);
- freeary(ns, sma);
- total++;
- }
- mutex_unlock(&sem_ids(ns).mutex);
-
- kfree(ns->ids[IPC_SEM_IDS]);
- ns->ids[IPC_SEM_IDS] = NULL;
+ free_ipcs(ns, &sem_ids(ns), freeary);
}
+#endif
void __init sem_init (void)
{
- __sem_init_ns(&init_ipc_ns, &init_sem_ids);
+ sem_init_ns(&init_ipc_ns);
ipc_init_proc_interface("sysvipc/sem",
" key semid perms nsems uid gid cuid cgid otime ctime\n",
IPC_SEM_IDS, sysvipc_sem_proc_show);
}
+/*
+ * This routine is called in the paths where the rw_mutex is held to protect
+ * access to the idr tree.
+ */
+static inline struct sem_array *sem_lock_check_down(struct ipc_namespace *ns,
+ int id)
+{
+ struct kern_ipc_perm *ipcp = ipc_lock_check_down(&sem_ids(ns), id);
+
+ if (IS_ERR(ipcp))
+ return (struct sem_array *)ipcp;
+
+ return container_of(ipcp, struct sem_array, sem_perm);
+}
+
+/*
+ * sem_lock_(check_) routines are called in the paths where the rw_mutex
+ * is not held.
+ */
static inline struct sem_array *sem_lock(struct ipc_namespace *ns, int id)
{
struct kern_ipc_perm *ipcp = ipc_lock(&sem_ids(ns), id);
+ if (IS_ERR(ipcp))
+ return (struct sem_array *)ipcp;
+
return container_of(ipcp, struct sem_array, sem_perm);
}
{
struct kern_ipc_perm *ipcp = ipc_lock_check(&sem_ids(ns), id);
+ if (IS_ERR(ipcp))
+ return (struct sem_array *)ipcp;
+
return container_of(ipcp, struct sem_array, sem_perm);
}
* @ns: namespace
* @params: ptr to the structure that contains key, semflg and nsems
*
- * Called with sem_ids.mutex held
+ * Called with sem_ids.rw_mutex held (as a writer)
*/
static int newary(struct ipc_namespace *ns, struct ipc_params *params)
}
id = ipc_addid(&sem_ids(ns), &sma->sem_perm, ns->sc_semmni);
- if(id == -1) {
+ if (id < 0) {
security_sem_free(sma);
ipc_rcu_putref(sma);
- return -ENOSPC;
+ return id;
}
ns->used_sems += nsems;
- sma->sem_perm.id = sem_buildid(ns, id, sma->sem_perm.seq);
+ sma->sem_perm.id = sem_buildid(id, sma->sem_perm.seq);
sma->sem_base = (struct sem *) &sma[1];
/* sma->sem_pending = NULL; */
sma->sem_pending_last = &sma->sem_pending;
/*
- * Called with sem_ids.mutex and ipcp locked.
+ * Called with sem_ids.rw_mutex and ipcp locked.
*/
static inline int sem_security(struct kern_ipc_perm *ipcp, int semflg)
{
}
/*
- * Called with sem_ids.mutex and ipcp locked.
+ * Called with sem_ids.rw_mutex and ipcp locked.
*/
static inline int sem_more_checks(struct kern_ipc_perm *ipcp,
struct ipc_params *params)
return semzcnt;
}
-/* Free a semaphore set. freeary() is called with sem_ids.mutex locked and
- * the spinlock for this semaphore set hold. sem_ids.mutex remains locked
- * on exit.
+/* Free a semaphore set. freeary() is called with sem_ids.rw_mutex locked
+ * as a writer and the spinlock for this semaphore set hold. sem_ids.rw_mutex
+ * remains locked on exit.
*/
-static void freeary(struct ipc_namespace *ns, struct sem_array *sma)
+static void freeary(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
{
struct sem_undo *un;
struct sem_queue *q;
+ struct sem_array *sma = container_of(ipcp, struct sem_array, sem_perm);
/* Invalidate the existing undo structures for this semaphore set.
* (They will be freed without any further action in exit_sem()
}
}
-static int semctl_nolock(struct ipc_namespace *ns, int semid, int semnum,
- int cmd, int version, union semun arg)
+static int semctl_nolock(struct ipc_namespace *ns, int semid,
+ int cmd, int version, union semun arg)
{
int err = -EINVAL;
struct sem_array *sma;
seminfo.semmnu = SEMMNU;
seminfo.semmap = SEMMAP;
seminfo.semume = SEMUME;
- mutex_lock(&sem_ids(ns).mutex);
+ down_read(&sem_ids(ns).rw_mutex);
if (cmd == SEM_INFO) {
seminfo.semusz = sem_ids(ns).in_use;
seminfo.semaem = ns->used_sems;
seminfo.semaem = SEMAEM;
}
max_id = ipc_get_maxid(&sem_ids(ns));
- mutex_unlock(&sem_ids(ns).mutex);
+ up_read(&sem_ids(ns).rw_mutex);
if (copy_to_user (arg.__buf, &seminfo, sizeof(struct seminfo)))
return -EFAULT;
return (max_id < 0) ? 0: max_id;
}
+ case IPC_STAT:
case SEM_STAT:
{
struct semid64_ds tbuf;
int id;
- sma = sem_lock(ns, semid);
- if (IS_ERR(sma))
- return PTR_ERR(sma);
+ if (cmd == SEM_STAT) {
+ sma = sem_lock(ns, semid);
+ if (IS_ERR(sma))
+ return PTR_ERR(sma);
+ id = sma->sem_perm.id;
+ } else {
+ sma = sem_lock_check(ns, semid);
+ if (IS_ERR(sma))
+ return PTR_ERR(sma);
+ id = 0;
+ }
err = -EACCES;
if (ipcperms (&sma->sem_perm, S_IRUGO))
if (err)
goto out_unlock;
- id = sma->sem_perm.id;
-
memset(&tbuf, 0, sizeof(tbuf));
kernel_to_ipc64_perm(&sma->sem_perm, &tbuf.sem_perm);
err = 0;
goto out_unlock;
}
- case IPC_STAT:
- {
- struct semid64_ds tbuf;
- memset(&tbuf,0,sizeof(tbuf));
- kernel_to_ipc64_perm(&sma->sem_perm, &tbuf.sem_perm);
- tbuf.sem_otime = sma->sem_otime;
- tbuf.sem_ctime = sma->sem_ctime;
- tbuf.sem_nsems = sma->sem_nsems;
- sem_unlock(sma);
- if (copy_semid_to_user (arg.buf, &tbuf, version))
- return -EFAULT;
- return 0;
- }
/* GETVAL, GETPID, GETNCTN, GETZCNT, SETVAL: fall-through */
}
err = -EINVAL;
if(copy_semid_from_user (&setbuf, arg.buf, version))
return -EFAULT;
}
- sma = sem_lock_check(ns, semid);
+ sma = sem_lock_check_down(ns, semid);
if (IS_ERR(sma))
return PTR_ERR(sma);
switch(cmd){
case IPC_RMID:
- freeary(ns, sma);
+ freeary(ns, ipcp);
err = 0;
break;
case IPC_SET:
switch(cmd) {
case IPC_INFO:
case SEM_INFO:
+ case IPC_STAT:
case SEM_STAT:
- err = semctl_nolock(ns,semid,semnum,cmd,version,arg);
+ err = semctl_nolock(ns, semid, cmd, version, arg);
return err;
case GETALL:
case GETVAL:
case GETPID:
case GETNCNT:
case GETZCNT:
- case IPC_STAT:
case SETVAL:
case SETALL:
err = semctl_main(ns,semid,semnum,cmd,version,arg);
return err;
case IPC_RMID:
case IPC_SET:
- mutex_lock(&sem_ids(ns).mutex);
+ down_write(&sem_ids(ns).rw_mutex);
err = semctl_down(ns,semid,semnum,cmd,version,arg);
- mutex_unlock(&sem_ids(ns).mutex);
+ up_write(&sem_ids(ns).rw_mutex);
return err;
default:
return -EINVAL;
}
}
-static inline void lock_semundo(void)
-{
- struct sem_undo_list *undo_list;
-
- undo_list = current->sysvsem.undo_list;
- if (undo_list)
- spin_lock(&undo_list->lock);
-}
-
-/* This code has an interaction with copy_semundo().
- * Consider; two tasks are sharing the undo_list. task1
- * acquires the undo_list lock in lock_semundo(). If task2 now
- * exits before task1 releases the lock (by calling
- * unlock_semundo()), then task1 will never call spin_unlock().
- * This leave the sem_undo_list in a locked state. If task1 now creats task3
- * and once again shares the sem_undo_list, the sem_undo_list will still be
- * locked, and future SEM_UNDO operations will deadlock. This case is
- * dealt with in copy_semundo() by having it reinitialize the spin lock when
- * the refcnt goes from 1 to 2.
- */
-static inline void unlock_semundo(void)
-{
- struct sem_undo_list *undo_list;
-
- undo_list = current->sysvsem.undo_list;
- if (undo_list)
- spin_unlock(&undo_list->lock);
-}
-
-
/* If the task doesn't already have a undo_list, then allocate one
* here. We guarantee there is only one thread using this undo list,
* and current is THE ONE
if (error)
return ERR_PTR(error);
- lock_semundo();
+ spin_lock(&ulp->lock);
un = lookup_undo(ulp, semid);
- unlock_semundo();
+ spin_unlock(&ulp->lock);
if (likely(un!=NULL))
goto out;
new->semadj = (short *) &new[1];
new->semid = semid;
- lock_semundo();
+ spin_lock(&ulp->lock);
un = lookup_undo(ulp, semid);
if (un) {
- unlock_semundo();
+ spin_unlock(&ulp->lock);
kfree(new);
ipc_lock_by_ptr(&sma->sem_perm);
ipc_rcu_putref(sma);
ipc_rcu_putref(sma);
if (sma->sem_perm.deleted) {
sem_unlock(sma);
- unlock_semundo();
+ spin_unlock(&ulp->lock);
kfree(new);
un = ERR_PTR(-EIDRM);
goto out;
sma->undo = new;
sem_unlock(sma);
un = new;
- unlock_semundo();
+ spin_unlock(&ulp->lock);
out:
return un;
}
/* If CLONE_SYSVSEM is set, establish sharing of SEM_UNDO state between
* parent and child tasks.
- *
- * See the notes above unlock_semundo() regarding the spin_lock_init()
- * in this code. Initialize the undo_list->lock here instead of get_undo_list()
- * because of the reasoning in the comment above unlock_semundo.
*/
int copy_semundo(unsigned long clone_flags, struct task_struct *tsk)
if (u->semid == -1)
goto next_entry;
- BUG_ON(sem_checkid(ns,sma,u->semid));
+ BUG_ON(sem_checkid(sma, u->semid));
/* remove u from the sma->undo list */
for (unp = &sma->undo; (un = *unp); unp = &un->id_next) {
git.samba.org / sfrench / cifs-2.6.git / blobdiff