ns->shm_ctlmax = SHMMAX;
ns->shm_ctlall = SHMALL;
ns->shm_ctlmni = SHMMNI;
+ ns->shm_rmid_forced = 0;
ns->shm_tot = 0;
ipc_init_ids(&shm_ids(ns));
}
return container_of(ipcp, struct shmid_kernel, shm_perm);
}
+static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
+{
+ rcu_read_lock();
+ spin_lock(&ipcp->shm_perm.lock);
+}
+
static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
int id)
{
ipc_rcu_putref(shp);
}
+/*
+ * shm_may_destroy - identifies whether shm segment should be destroyed now
+ *
+ * Returns true if and only if there are no active users of the segment and
+ * one of the following is true:
+ *
+ * 1) shmctl(id, IPC_RMID, NULL) was called for this shp
+ *
+ * 2) sysctl kernel.shm_rmid_forced is set to 1.
+ */
+static bool shm_may_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
+{
+ return (shp->shm_nattch == 0) &&
+ (ns->shm_rmid_forced ||
+ (shp->shm_perm.mode & SHM_DEST));
+}
+
/*
* remove the attach descriptor vma.
* free memory for segment if it is marked destroyed.
shp->shm_lprid = task_tgid_vnr(current);
shp->shm_dtim = get_seconds();
shp->shm_nattch--;
- if(shp->shm_nattch == 0 &&
- shp->shm_perm.mode & SHM_DEST)
+ if (shm_may_destroy(ns, shp))
shm_destroy(ns, shp);
else
shm_unlock(shp);
up_write(&shm_ids(ns).rw_mutex);
}
+/* Called with ns->shm_ids(ns).rw_mutex locked */
+static int shm_try_destroy_current(int id, void *p, void *data)
+{
+ struct ipc_namespace *ns = data;
+ struct kern_ipc_perm *ipcp = p;
+ struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
+
+ if (shp->shm_creator != current)
+ return 0;
+
+ /*
+ * Mark it as orphaned to destroy the segment when
+ * kernel.shm_rmid_forced is changed.
+ * It is noop if the following shm_may_destroy() returns true.
+ */
+ shp->shm_creator = NULL;
+
+ /*
+ * Don't even try to destroy it. If shm_rmid_forced=0 and IPC_RMID
+ * is not set, it shouldn't be deleted here.
+ */
+ if (!ns->shm_rmid_forced)
+ return 0;
+
+ if (shm_may_destroy(ns, shp)) {
+ shm_lock_by_ptr(shp);
+ shm_destroy(ns, shp);
+ }
+ return 0;
+}
+
+/* Called with ns->shm_ids(ns).rw_mutex locked */
+static int shm_try_destroy_orphaned(int id, void *p, void *data)
+{
+ struct ipc_namespace *ns = data;
+ struct kern_ipc_perm *ipcp = p;
+ struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
+
+ /*
+ * We want to destroy segments without users and with already
+ * exit'ed originating process.
+ *
+ * As shp->* are changed under rw_mutex, it's safe to skip shp locking.
+ */
+ if (shp->shm_creator != NULL)
+ return 0;
+
+ if (shm_may_destroy(ns, shp)) {
+ shm_lock_by_ptr(shp);
+ shm_destroy(ns, shp);
+ }
+ return 0;
+}
+
+void shm_destroy_orphaned(struct ipc_namespace *ns)
+{
+ down_write(&shm_ids(ns).rw_mutex);
+ if (shm_ids(ns).in_use)
+ idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns);
+ up_write(&shm_ids(ns).rw_mutex);
+}
+
+
+void exit_shm(struct task_struct *task)
+{
+ struct ipc_namespace *ns = task->nsproxy->ipc_ns;
+
+ if (shm_ids(ns).in_use == 0)
+ return;
+
+ /* Destroy all already created segments, but not mapped yet */
+ down_write(&shm_ids(ns).rw_mutex);
+ if (shm_ids(ns).in_use)
+ idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_current, ns);
+ up_write(&shm_ids(ns).rw_mutex);
+}
+
static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
struct file *file = vma->vm_file;
return 0;
}
-static int shm_fsync(struct file *file, int datasync)
+static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
{
struct shm_file_data *sfd = shm_file_data(file);
if (!sfd->file->f_op->fsync)
return -EINVAL;
- return sfd->file->f_op->fsync(sfd->file, datasync);
+ return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
}
static unsigned long shm_get_unmapped_area(struct file *file,
struct file * file;
char name[13];
int id;
- int acctflag = 0;
+ vm_flags_t acctflag = 0;
if (size < SHMMIN || size > ns->shm_ctlmax)
return -EINVAL;
shp->shm_segsz = size;
shp->shm_nattch = 0;
shp->shm_file = file;
+ shp->shm_creator = current;
/*
* shmid gets reported as "inode#" in /proc/pid/maps.
* proc-ps tools use this. Changing this will break them.
shp = shm_lock(ns, shmid);
BUG_ON(IS_ERR(shp));
shp->shm_nattch--;
- if(shp->shm_nattch == 0 &&
- shp->shm_perm.mode & SHM_DEST)
+ if (shm_may_destroy(ns, shp))
shm_destroy(ns, shp);
else
shm_unlock(shp);