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![James Morris](/assets/img/avatar_default.png)
Make all seq_operations structs const, to help mitigate against revectoring user-triggerable function pointers. This is derived from the grsecurity patch, although generated from scratch because it's simpler than extracting the changes from there. Signed-off-by: James Morris <jmorris@namei.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
993 lines
23 KiB
C
993 lines
23 KiB
C
/*
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* linux/ipc/util.c
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* Copyright (C) 1992 Krishna Balasubramanian
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*
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* Sep 1997 - Call suser() last after "normal" permission checks so we
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* get BSD style process accounting right.
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* Occurs in several places in the IPC code.
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* Chris Evans, <chris@ferret.lmh.ox.ac.uk>
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* Nov 1999 - ipc helper functions, unified SMP locking
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* Manfred Spraul <manfred@colorfullife.com>
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* Oct 2002 - One lock per IPC id. RCU ipc_free for lock-free grow_ary().
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* Mingming Cao <cmm@us.ibm.com>
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* Mar 2006 - support for audit of ipc object properties
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* Dustin Kirkland <dustin.kirkland@us.ibm.com>
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* Jun 2006 - namespaces ssupport
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* OpenVZ, SWsoft Inc.
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* Pavel Emelianov <xemul@openvz.org>
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*/
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#include <linux/mm.h>
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#include <linux/shm.h>
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#include <linux/init.h>
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#include <linux/msg.h>
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#include <linux/vmalloc.h>
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#include <linux/slab.h>
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#include <linux/capability.h>
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#include <linux/highuid.h>
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#include <linux/security.h>
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#include <linux/rcupdate.h>
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#include <linux/workqueue.h>
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#include <linux/seq_file.h>
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#include <linux/proc_fs.h>
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#include <linux/audit.h>
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#include <linux/nsproxy.h>
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#include <linux/rwsem.h>
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#include <linux/memory.h>
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#include <linux/ipc_namespace.h>
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#include <asm/unistd.h>
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#include "util.h"
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struct ipc_proc_iface {
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const char *path;
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const char *header;
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int ids;
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int (*show)(struct seq_file *, void *);
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};
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#ifdef CONFIG_MEMORY_HOTPLUG
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static void ipc_memory_notifier(struct work_struct *work)
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{
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ipcns_notify(IPCNS_MEMCHANGED);
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}
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static DECLARE_WORK(ipc_memory_wq, ipc_memory_notifier);
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static int ipc_memory_callback(struct notifier_block *self,
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unsigned long action, void *arg)
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{
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switch (action) {
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case MEM_ONLINE: /* memory successfully brought online */
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case MEM_OFFLINE: /* or offline: it's time to recompute msgmni */
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/*
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* This is done by invoking the ipcns notifier chain with the
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* IPC_MEMCHANGED event.
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* In order not to keep the lock on the hotplug memory chain
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* for too long, queue a work item that will, when waken up,
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* activate the ipcns notification chain.
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* No need to keep several ipc work items on the queue.
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*/
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if (!work_pending(&ipc_memory_wq))
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schedule_work(&ipc_memory_wq);
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break;
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case MEM_GOING_ONLINE:
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case MEM_GOING_OFFLINE:
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case MEM_CANCEL_ONLINE:
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case MEM_CANCEL_OFFLINE:
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default:
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break;
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}
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return NOTIFY_OK;
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}
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#endif /* CONFIG_MEMORY_HOTPLUG */
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/**
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* ipc_init - initialise IPC subsystem
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*
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* The various system5 IPC resources (semaphores, messages and shared
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* memory) are initialised
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* A callback routine is registered into the memory hotplug notifier
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* chain: since msgmni scales to lowmem this callback routine will be
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* called upon successful memory add / remove to recompute msmgni.
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*/
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static int __init ipc_init(void)
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{
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sem_init();
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msg_init();
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shm_init();
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hotplug_memory_notifier(ipc_memory_callback, IPC_CALLBACK_PRI);
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register_ipcns_notifier(&init_ipc_ns);
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return 0;
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}
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__initcall(ipc_init);
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/**
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* ipc_init_ids - initialise IPC identifiers
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* @ids: Identifier set
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*
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* Set up the sequence range to use for the ipc identifier range (limited
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* below IPCMNI) then initialise the ids idr.
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*/
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void ipc_init_ids(struct ipc_ids *ids)
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{
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init_rwsem(&ids->rw_mutex);
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ids->in_use = 0;
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ids->seq = 0;
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{
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int seq_limit = INT_MAX/SEQ_MULTIPLIER;
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if (seq_limit > USHORT_MAX)
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ids->seq_max = USHORT_MAX;
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else
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ids->seq_max = seq_limit;
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}
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idr_init(&ids->ipcs_idr);
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}
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#ifdef CONFIG_PROC_FS
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static const struct file_operations sysvipc_proc_fops;
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/**
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* ipc_init_proc_interface - Create a proc interface for sysipc types using a seq_file interface.
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* @path: Path in procfs
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* @header: Banner to be printed at the beginning of the file.
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* @ids: ipc id table to iterate.
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* @show: show routine.
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*/
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void __init ipc_init_proc_interface(const char *path, const char *header,
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int ids, int (*show)(struct seq_file *, void *))
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{
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struct proc_dir_entry *pde;
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struct ipc_proc_iface *iface;
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iface = kmalloc(sizeof(*iface), GFP_KERNEL);
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if (!iface)
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return;
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iface->path = path;
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iface->header = header;
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iface->ids = ids;
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iface->show = show;
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pde = proc_create_data(path,
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S_IRUGO, /* world readable */
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NULL, /* parent dir */
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&sysvipc_proc_fops,
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iface);
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if (!pde) {
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kfree(iface);
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}
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}
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#endif
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/**
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* ipc_findkey - find a key in an ipc identifier set
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* @ids: Identifier set
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* @key: The key to find
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*
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* Requires ipc_ids.rw_mutex locked.
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* Returns the LOCKED pointer to the ipc structure if found or NULL
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* if not.
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* If key is found ipc points to the owning ipc structure
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*/
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static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key)
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{
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struct kern_ipc_perm *ipc;
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int next_id;
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int total;
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for (total = 0, next_id = 0; total < ids->in_use; next_id++) {
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ipc = idr_find(&ids->ipcs_idr, next_id);
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if (ipc == NULL)
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continue;
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if (ipc->key != key) {
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total++;
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continue;
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}
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ipc_lock_by_ptr(ipc);
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return ipc;
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}
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return NULL;
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}
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/**
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* ipc_get_maxid - get the last assigned id
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* @ids: IPC identifier set
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*
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* Called with ipc_ids.rw_mutex held.
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*/
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int ipc_get_maxid(struct ipc_ids *ids)
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{
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struct kern_ipc_perm *ipc;
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int max_id = -1;
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int total, id;
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if (ids->in_use == 0)
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return -1;
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if (ids->in_use == IPCMNI)
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return IPCMNI - 1;
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/* Look for the last assigned id */
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total = 0;
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for (id = 0; id < IPCMNI && total < ids->in_use; id++) {
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ipc = idr_find(&ids->ipcs_idr, id);
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if (ipc != NULL) {
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max_id = id;
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total++;
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}
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}
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return max_id;
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}
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/**
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* ipc_addid - add an IPC identifier
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* @ids: IPC identifier set
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* @new: new IPC permission set
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* @size: limit for the number of used ids
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*
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* Add an entry 'new' to the IPC ids idr. The permissions object is
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* initialised and the first free entry is set up and the id assigned
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* is returned. The 'new' entry is returned in a locked state on success.
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* On failure the entry is not locked and a negative err-code is returned.
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*
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* Called with ipc_ids.rw_mutex held as a writer.
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*/
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int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size)
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{
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uid_t euid;
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gid_t egid;
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int id, err;
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if (size > IPCMNI)
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size = IPCMNI;
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if (ids->in_use >= size)
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return -ENOSPC;
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spin_lock_init(&new->lock);
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new->deleted = 0;
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rcu_read_lock();
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spin_lock(&new->lock);
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err = idr_get_new(&ids->ipcs_idr, new, &id);
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if (err) {
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spin_unlock(&new->lock);
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rcu_read_unlock();
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return err;
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}
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ids->in_use++;
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current_euid_egid(&euid, &egid);
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new->cuid = new->uid = euid;
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new->gid = new->cgid = egid;
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new->seq = ids->seq++;
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if(ids->seq > ids->seq_max)
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ids->seq = 0;
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new->id = ipc_buildid(id, new->seq);
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return id;
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}
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/**
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* ipcget_new - create a new ipc object
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* @ns: namespace
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* @ids: IPC identifer set
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* @ops: the actual creation routine to call
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* @params: its parameters
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*
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* This routine is called by sys_msgget, sys_semget() and sys_shmget()
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* when the key is IPC_PRIVATE.
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*/
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static int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids,
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struct ipc_ops *ops, struct ipc_params *params)
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{
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int err;
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retry:
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err = idr_pre_get(&ids->ipcs_idr, GFP_KERNEL);
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if (!err)
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return -ENOMEM;
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down_write(&ids->rw_mutex);
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err = ops->getnew(ns, params);
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up_write(&ids->rw_mutex);
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if (err == -EAGAIN)
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goto retry;
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return err;
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}
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/**
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* ipc_check_perms - check security and permissions for an IPC
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* @ipcp: ipc permission set
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* @ops: the actual security routine to call
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* @params: its parameters
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*
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* This routine is called by sys_msgget(), sys_semget() and sys_shmget()
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* when the key is not IPC_PRIVATE and that key already exists in the
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* ids IDR.
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*
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* On success, the IPC id is returned.
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*
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* It is called with ipc_ids.rw_mutex and ipcp->lock held.
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*/
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static int ipc_check_perms(struct kern_ipc_perm *ipcp, struct ipc_ops *ops,
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struct ipc_params *params)
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{
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int err;
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if (ipcperms(ipcp, params->flg))
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err = -EACCES;
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else {
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err = ops->associate(ipcp, params->flg);
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if (!err)
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err = ipcp->id;
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}
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return err;
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}
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/**
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* ipcget_public - get an ipc object or create a new one
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* @ns: namespace
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* @ids: IPC identifer set
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* @ops: the actual creation routine to call
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* @params: its parameters
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*
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* This routine is called by sys_msgget, sys_semget() and sys_shmget()
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* when the key is not IPC_PRIVATE.
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* It adds a new entry if the key is not found and does some permission
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* / security checkings if the key is found.
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*
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* On success, the ipc id is returned.
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*/
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static int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids,
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struct ipc_ops *ops, struct ipc_params *params)
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{
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struct kern_ipc_perm *ipcp;
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int flg = params->flg;
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int err;
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retry:
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err = idr_pre_get(&ids->ipcs_idr, GFP_KERNEL);
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/*
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* Take the lock as a writer since we are potentially going to add
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* a new entry + read locks are not "upgradable"
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*/
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down_write(&ids->rw_mutex);
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ipcp = ipc_findkey(ids, params->key);
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if (ipcp == NULL) {
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/* key not used */
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if (!(flg & IPC_CREAT))
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err = -ENOENT;
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else if (!err)
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err = -ENOMEM;
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else
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err = ops->getnew(ns, params);
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} else {
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/* ipc object has been locked by ipc_findkey() */
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if (flg & IPC_CREAT && flg & IPC_EXCL)
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err = -EEXIST;
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else {
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err = 0;
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if (ops->more_checks)
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err = ops->more_checks(ipcp, params);
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if (!err)
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/*
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* ipc_check_perms returns the IPC id on
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* success
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*/
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err = ipc_check_perms(ipcp, ops, params);
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}
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ipc_unlock(ipcp);
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}
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up_write(&ids->rw_mutex);
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if (err == -EAGAIN)
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goto retry;
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return err;
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}
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/**
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* ipc_rmid - remove an IPC identifier
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* @ids: IPC identifier set
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* @ipcp: ipc perm structure containing the identifier to remove
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*
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* ipc_ids.rw_mutex (as a writer) and the spinlock for this ID are held
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* before this function is called, and remain locked on the exit.
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*/
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void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp)
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{
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int lid = ipcid_to_idx(ipcp->id);
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idr_remove(&ids->ipcs_idr, lid);
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ids->in_use--;
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ipcp->deleted = 1;
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return;
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}
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/**
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* ipc_alloc - allocate ipc space
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* @size: size desired
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*
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* Allocate memory from the appropriate pools and return a pointer to it.
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* NULL is returned if the allocation fails
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*/
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void* ipc_alloc(int size)
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{
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void* out;
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if(size > PAGE_SIZE)
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out = vmalloc(size);
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else
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out = kmalloc(size, GFP_KERNEL);
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return out;
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}
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/**
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* ipc_free - free ipc space
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* @ptr: pointer returned by ipc_alloc
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* @size: size of block
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*
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* Free a block created with ipc_alloc(). The caller must know the size
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* used in the allocation call.
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*/
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void ipc_free(void* ptr, int size)
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{
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if(size > PAGE_SIZE)
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vfree(ptr);
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else
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kfree(ptr);
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}
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/*
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* rcu allocations:
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* There are three headers that are prepended to the actual allocation:
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* - during use: ipc_rcu_hdr.
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* - during the rcu grace period: ipc_rcu_grace.
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* - [only if vmalloc]: ipc_rcu_sched.
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* Their lifetime doesn't overlap, thus the headers share the same memory.
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* Unlike a normal union, they are right-aligned, thus some container_of
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* forward/backward casting is necessary:
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*/
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struct ipc_rcu_hdr
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{
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int refcount;
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int is_vmalloc;
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void *data[0];
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};
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struct ipc_rcu_grace
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{
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struct rcu_head rcu;
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/* "void *" makes sure alignment of following data is sane. */
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void *data[0];
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};
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struct ipc_rcu_sched
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{
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struct work_struct work;
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/* "void *" makes sure alignment of following data is sane. */
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void *data[0];
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};
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#define HDRLEN_KMALLOC (sizeof(struct ipc_rcu_grace) > sizeof(struct ipc_rcu_hdr) ? \
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sizeof(struct ipc_rcu_grace) : sizeof(struct ipc_rcu_hdr))
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#define HDRLEN_VMALLOC (sizeof(struct ipc_rcu_sched) > HDRLEN_KMALLOC ? \
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sizeof(struct ipc_rcu_sched) : HDRLEN_KMALLOC)
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static inline int rcu_use_vmalloc(int size)
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{
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/* Too big for a single page? */
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if (HDRLEN_KMALLOC + size > PAGE_SIZE)
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return 1;
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return 0;
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}
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/**
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* ipc_rcu_alloc - allocate ipc and rcu space
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* @size: size desired
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*
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* Allocate memory for the rcu header structure + the object.
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* Returns the pointer to the object.
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* NULL is returned if the allocation fails.
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*/
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void* ipc_rcu_alloc(int size)
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{
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void* out;
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/*
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* We prepend the allocation with the rcu struct, and
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* workqueue if necessary (for vmalloc).
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*/
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if (rcu_use_vmalloc(size)) {
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out = vmalloc(HDRLEN_VMALLOC + size);
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if (out) {
|
|
out += HDRLEN_VMALLOC;
|
|
container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 1;
|
|
container_of(out, struct ipc_rcu_hdr, data)->refcount = 1;
|
|
}
|
|
} else {
|
|
out = kmalloc(HDRLEN_KMALLOC + size, GFP_KERNEL);
|
|
if (out) {
|
|
out += HDRLEN_KMALLOC;
|
|
container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 0;
|
|
container_of(out, struct ipc_rcu_hdr, data)->refcount = 1;
|
|
}
|
|
}
|
|
|
|
return out;
|
|
}
|
|
|
|
void ipc_rcu_getref(void *ptr)
|
|
{
|
|
container_of(ptr, struct ipc_rcu_hdr, data)->refcount++;
|
|
}
|
|
|
|
static void ipc_do_vfree(struct work_struct *work)
|
|
{
|
|
vfree(container_of(work, struct ipc_rcu_sched, work));
|
|
}
|
|
|
|
/**
|
|
* ipc_schedule_free - free ipc + rcu space
|
|
* @head: RCU callback structure for queued work
|
|
*
|
|
* Since RCU callback function is called in bh,
|
|
* we need to defer the vfree to schedule_work().
|
|
*/
|
|
static void ipc_schedule_free(struct rcu_head *head)
|
|
{
|
|
struct ipc_rcu_grace *grace;
|
|
struct ipc_rcu_sched *sched;
|
|
|
|
grace = container_of(head, struct ipc_rcu_grace, rcu);
|
|
sched = container_of(&(grace->data[0]), struct ipc_rcu_sched,
|
|
data[0]);
|
|
|
|
INIT_WORK(&sched->work, ipc_do_vfree);
|
|
schedule_work(&sched->work);
|
|
}
|
|
|
|
/**
|
|
* ipc_immediate_free - free ipc + rcu space
|
|
* @head: RCU callback structure that contains pointer to be freed
|
|
*
|
|
* Free from the RCU callback context.
|
|
*/
|
|
static void ipc_immediate_free(struct rcu_head *head)
|
|
{
|
|
struct ipc_rcu_grace *free =
|
|
container_of(head, struct ipc_rcu_grace, rcu);
|
|
kfree(free);
|
|
}
|
|
|
|
void ipc_rcu_putref(void *ptr)
|
|
{
|
|
if (--container_of(ptr, struct ipc_rcu_hdr, data)->refcount > 0)
|
|
return;
|
|
|
|
if (container_of(ptr, struct ipc_rcu_hdr, data)->is_vmalloc) {
|
|
call_rcu(&container_of(ptr, struct ipc_rcu_grace, data)->rcu,
|
|
ipc_schedule_free);
|
|
} else {
|
|
call_rcu(&container_of(ptr, struct ipc_rcu_grace, data)->rcu,
|
|
ipc_immediate_free);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* ipcperms - check IPC permissions
|
|
* @ipcp: IPC permission set
|
|
* @flag: desired permission set.
|
|
*
|
|
* Check user, group, other permissions for access
|
|
* to ipc resources. return 0 if allowed
|
|
*/
|
|
|
|
int ipcperms (struct kern_ipc_perm *ipcp, short flag)
|
|
{ /* flag will most probably be 0 or S_...UGO from <linux/stat.h> */
|
|
uid_t euid = current_euid();
|
|
int requested_mode, granted_mode;
|
|
|
|
audit_ipc_obj(ipcp);
|
|
requested_mode = (flag >> 6) | (flag >> 3) | flag;
|
|
granted_mode = ipcp->mode;
|
|
if (euid == ipcp->cuid ||
|
|
euid == ipcp->uid)
|
|
granted_mode >>= 6;
|
|
else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid))
|
|
granted_mode >>= 3;
|
|
/* is there some bit set in requested_mode but not in granted_mode? */
|
|
if ((requested_mode & ~granted_mode & 0007) &&
|
|
!capable(CAP_IPC_OWNER))
|
|
return -1;
|
|
|
|
return security_ipc_permission(ipcp, flag);
|
|
}
|
|
|
|
/*
|
|
* Functions to convert between the kern_ipc_perm structure and the
|
|
* old/new ipc_perm structures
|
|
*/
|
|
|
|
/**
|
|
* kernel_to_ipc64_perm - convert kernel ipc permissions to user
|
|
* @in: kernel permissions
|
|
* @out: new style IPC permissions
|
|
*
|
|
* Turn the kernel object @in into a set of permissions descriptions
|
|
* for returning to userspace (@out).
|
|
*/
|
|
|
|
|
|
void kernel_to_ipc64_perm (struct kern_ipc_perm *in, struct ipc64_perm *out)
|
|
{
|
|
out->key = in->key;
|
|
out->uid = in->uid;
|
|
out->gid = in->gid;
|
|
out->cuid = in->cuid;
|
|
out->cgid = in->cgid;
|
|
out->mode = in->mode;
|
|
out->seq = in->seq;
|
|
}
|
|
|
|
/**
|
|
* ipc64_perm_to_ipc_perm - convert new ipc permissions to old
|
|
* @in: new style IPC permissions
|
|
* @out: old style IPC permissions
|
|
*
|
|
* Turn the new style permissions object @in into a compatibility
|
|
* object and store it into the @out pointer.
|
|
*/
|
|
|
|
void ipc64_perm_to_ipc_perm (struct ipc64_perm *in, struct ipc_perm *out)
|
|
{
|
|
out->key = in->key;
|
|
SET_UID(out->uid, in->uid);
|
|
SET_GID(out->gid, in->gid);
|
|
SET_UID(out->cuid, in->cuid);
|
|
SET_GID(out->cgid, in->cgid);
|
|
out->mode = in->mode;
|
|
out->seq = in->seq;
|
|
}
|
|
|
|
/**
|
|
* ipc_lock - Lock an ipc structure without rw_mutex held
|
|
* @ids: IPC identifier set
|
|
* @id: ipc id to look for
|
|
*
|
|
* Look for an id in the ipc ids idr and lock the associated ipc object.
|
|
*
|
|
* The ipc object is locked on exit.
|
|
*/
|
|
|
|
struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id)
|
|
{
|
|
struct kern_ipc_perm *out;
|
|
int lid = ipcid_to_idx(id);
|
|
|
|
rcu_read_lock();
|
|
out = idr_find(&ids->ipcs_idr, lid);
|
|
if (out == NULL) {
|
|
rcu_read_unlock();
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
spin_lock(&out->lock);
|
|
|
|
/* ipc_rmid() may have already freed the ID while ipc_lock
|
|
* was spinning: here verify that the structure is still valid
|
|
*/
|
|
if (out->deleted) {
|
|
spin_unlock(&out->lock);
|
|
rcu_read_unlock();
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
return out;
|
|
}
|
|
|
|
struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids, int id)
|
|
{
|
|
struct kern_ipc_perm *out;
|
|
|
|
out = ipc_lock(ids, id);
|
|
if (IS_ERR(out))
|
|
return out;
|
|
|
|
if (ipc_checkid(out, id)) {
|
|
ipc_unlock(out);
|
|
return ERR_PTR(-EIDRM);
|
|
}
|
|
|
|
return out;
|
|
}
|
|
|
|
/**
|
|
* ipcget - Common sys_*get() code
|
|
* @ns : namsepace
|
|
* @ids : IPC identifier set
|
|
* @ops : operations to be called on ipc object creation, permission checks
|
|
* and further checks
|
|
* @params : the parameters needed by the previous operations.
|
|
*
|
|
* Common routine called by sys_msgget(), sys_semget() and sys_shmget().
|
|
*/
|
|
int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
|
|
struct ipc_ops *ops, struct ipc_params *params)
|
|
{
|
|
if (params->key == IPC_PRIVATE)
|
|
return ipcget_new(ns, ids, ops, params);
|
|
else
|
|
return ipcget_public(ns, ids, ops, params);
|
|
}
|
|
|
|
/**
|
|
* ipc_update_perm - update the permissions of an IPC.
|
|
* @in: the permission given as input.
|
|
* @out: the permission of the ipc to set.
|
|
*/
|
|
void ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out)
|
|
{
|
|
out->uid = in->uid;
|
|
out->gid = in->gid;
|
|
out->mode = (out->mode & ~S_IRWXUGO)
|
|
| (in->mode & S_IRWXUGO);
|
|
}
|
|
|
|
/**
|
|
* ipcctl_pre_down - retrieve an ipc and check permissions for some IPC_XXX cmd
|
|
* @ids: the table of ids where to look for the ipc
|
|
* @id: the id of the ipc to retrieve
|
|
* @cmd: the cmd to check
|
|
* @perm: the permission to set
|
|
* @extra_perm: one extra permission parameter used by msq
|
|
*
|
|
* This function does some common audit and permissions check for some IPC_XXX
|
|
* cmd and is called from semctl_down, shmctl_down and msgctl_down.
|
|
* It must be called without any lock held and
|
|
* - retrieves the ipc with the given id in the given table.
|
|
* - performs some audit and permission check, depending on the given cmd
|
|
* - returns the ipc with both ipc and rw_mutex locks held in case of success
|
|
* or an err-code without any lock held otherwise.
|
|
*/
|
|
struct kern_ipc_perm *ipcctl_pre_down(struct ipc_ids *ids, int id, int cmd,
|
|
struct ipc64_perm *perm, int extra_perm)
|
|
{
|
|
struct kern_ipc_perm *ipcp;
|
|
uid_t euid;
|
|
int err;
|
|
|
|
down_write(&ids->rw_mutex);
|
|
ipcp = ipc_lock_check(ids, id);
|
|
if (IS_ERR(ipcp)) {
|
|
err = PTR_ERR(ipcp);
|
|
goto out_up;
|
|
}
|
|
|
|
audit_ipc_obj(ipcp);
|
|
if (cmd == IPC_SET)
|
|
audit_ipc_set_perm(extra_perm, perm->uid,
|
|
perm->gid, perm->mode);
|
|
|
|
euid = current_euid();
|
|
if (euid == ipcp->cuid ||
|
|
euid == ipcp->uid || capable(CAP_SYS_ADMIN))
|
|
return ipcp;
|
|
|
|
err = -EPERM;
|
|
ipc_unlock(ipcp);
|
|
out_up:
|
|
up_write(&ids->rw_mutex);
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
#ifdef __ARCH_WANT_IPC_PARSE_VERSION
|
|
|
|
|
|
/**
|
|
* ipc_parse_version - IPC call version
|
|
* @cmd: pointer to command
|
|
*
|
|
* Return IPC_64 for new style IPC and IPC_OLD for old style IPC.
|
|
* The @cmd value is turned from an encoding command and version into
|
|
* just the command code.
|
|
*/
|
|
|
|
int ipc_parse_version (int *cmd)
|
|
{
|
|
if (*cmd & IPC_64) {
|
|
*cmd ^= IPC_64;
|
|
return IPC_64;
|
|
} else {
|
|
return IPC_OLD;
|
|
}
|
|
}
|
|
|
|
#endif /* __ARCH_WANT_IPC_PARSE_VERSION */
|
|
|
|
#ifdef CONFIG_PROC_FS
|
|
struct ipc_proc_iter {
|
|
struct ipc_namespace *ns;
|
|
struct ipc_proc_iface *iface;
|
|
};
|
|
|
|
/*
|
|
* This routine locks the ipc structure found at least at position pos.
|
|
*/
|
|
static struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos,
|
|
loff_t *new_pos)
|
|
{
|
|
struct kern_ipc_perm *ipc;
|
|
int total, id;
|
|
|
|
total = 0;
|
|
for (id = 0; id < pos && total < ids->in_use; id++) {
|
|
ipc = idr_find(&ids->ipcs_idr, id);
|
|
if (ipc != NULL)
|
|
total++;
|
|
}
|
|
|
|
if (total >= ids->in_use)
|
|
return NULL;
|
|
|
|
for ( ; pos < IPCMNI; pos++) {
|
|
ipc = idr_find(&ids->ipcs_idr, pos);
|
|
if (ipc != NULL) {
|
|
*new_pos = pos + 1;
|
|
ipc_lock_by_ptr(ipc);
|
|
return ipc;
|
|
}
|
|
}
|
|
|
|
/* Out of range - return NULL to terminate iteration */
|
|
return NULL;
|
|
}
|
|
|
|
static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos)
|
|
{
|
|
struct ipc_proc_iter *iter = s->private;
|
|
struct ipc_proc_iface *iface = iter->iface;
|
|
struct kern_ipc_perm *ipc = it;
|
|
|
|
/* If we had an ipc id locked before, unlock it */
|
|
if (ipc && ipc != SEQ_START_TOKEN)
|
|
ipc_unlock(ipc);
|
|
|
|
return sysvipc_find_ipc(&iter->ns->ids[iface->ids], *pos, pos);
|
|
}
|
|
|
|
/*
|
|
* File positions: pos 0 -> header, pos n -> ipc id = n - 1.
|
|
* SeqFile iterator: iterator value locked ipc pointer or SEQ_TOKEN_START.
|
|
*/
|
|
static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos)
|
|
{
|
|
struct ipc_proc_iter *iter = s->private;
|
|
struct ipc_proc_iface *iface = iter->iface;
|
|
struct ipc_ids *ids;
|
|
|
|
ids = &iter->ns->ids[iface->ids];
|
|
|
|
/*
|
|
* Take the lock - this will be released by the corresponding
|
|
* call to stop().
|
|
*/
|
|
down_read(&ids->rw_mutex);
|
|
|
|
/* pos < 0 is invalid */
|
|
if (*pos < 0)
|
|
return NULL;
|
|
|
|
/* pos == 0 means header */
|
|
if (*pos == 0)
|
|
return SEQ_START_TOKEN;
|
|
|
|
/* Find the (pos-1)th ipc */
|
|
return sysvipc_find_ipc(ids, *pos - 1, pos);
|
|
}
|
|
|
|
static void sysvipc_proc_stop(struct seq_file *s, void *it)
|
|
{
|
|
struct kern_ipc_perm *ipc = it;
|
|
struct ipc_proc_iter *iter = s->private;
|
|
struct ipc_proc_iface *iface = iter->iface;
|
|
struct ipc_ids *ids;
|
|
|
|
/* If we had a locked structure, release it */
|
|
if (ipc && ipc != SEQ_START_TOKEN)
|
|
ipc_unlock(ipc);
|
|
|
|
ids = &iter->ns->ids[iface->ids];
|
|
/* Release the lock we took in start() */
|
|
up_read(&ids->rw_mutex);
|
|
}
|
|
|
|
static int sysvipc_proc_show(struct seq_file *s, void *it)
|
|
{
|
|
struct ipc_proc_iter *iter = s->private;
|
|
struct ipc_proc_iface *iface = iter->iface;
|
|
|
|
if (it == SEQ_START_TOKEN)
|
|
return seq_puts(s, iface->header);
|
|
|
|
return iface->show(s, it);
|
|
}
|
|
|
|
static const struct seq_operations sysvipc_proc_seqops = {
|
|
.start = sysvipc_proc_start,
|
|
.stop = sysvipc_proc_stop,
|
|
.next = sysvipc_proc_next,
|
|
.show = sysvipc_proc_show,
|
|
};
|
|
|
|
static int sysvipc_proc_open(struct inode *inode, struct file *file)
|
|
{
|
|
int ret;
|
|
struct seq_file *seq;
|
|
struct ipc_proc_iter *iter;
|
|
|
|
ret = -ENOMEM;
|
|
iter = kmalloc(sizeof(*iter), GFP_KERNEL);
|
|
if (!iter)
|
|
goto out;
|
|
|
|
ret = seq_open(file, &sysvipc_proc_seqops);
|
|
if (ret)
|
|
goto out_kfree;
|
|
|
|
seq = file->private_data;
|
|
seq->private = iter;
|
|
|
|
iter->iface = PDE(inode)->data;
|
|
iter->ns = get_ipc_ns(current->nsproxy->ipc_ns);
|
|
out:
|
|
return ret;
|
|
out_kfree:
|
|
kfree(iter);
|
|
goto out;
|
|
}
|
|
|
|
static int sysvipc_proc_release(struct inode *inode, struct file *file)
|
|
{
|
|
struct seq_file *seq = file->private_data;
|
|
struct ipc_proc_iter *iter = seq->private;
|
|
put_ipc_ns(iter->ns);
|
|
return seq_release_private(inode, file);
|
|
}
|
|
|
|
static const struct file_operations sysvipc_proc_fops = {
|
|
.open = sysvipc_proc_open,
|
|
.read = seq_read,
|
|
.llseek = seq_lseek,
|
|
.release = sysvipc_proc_release,
|
|
};
|
|
#endif /* CONFIG_PROC_FS */
|