1/*
   2 * linux/ipc/shm.c
   3 * Copyright (C) 1992, 1993 Krishna Balasubramanian
   4 *	 Many improvements/fixes by Bruno Haible.
   5 * Replaced `struct shm_desc' by `struct vm_area_struct', July 1994.
   6 * Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli.
   7 *
   8 * /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
   9 * BIGMEM support, Andrea Arcangeli <andrea@suse.de>
  10 * SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr>
  11 * HIGHMEM support, Ingo Molnar <mingo@redhat.com>
  12 * Make shmmax, shmall, shmmni sysctl'able, Christoph Rohland <cr@sap.com>
  13 * Shared /dev/zero support, Kanoj Sarcar <kanoj@sgi.com>
  14 * Move the mm functionality over to mm/shmem.c, Christoph Rohland <cr@sap.com>
  15 *
  16 * support for audit of ipc object properties and permission changes
  17 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
  18 *
  19 * namespaces support
  20 * OpenVZ, SWsoft Inc.
  21 * Pavel Emelianov <xemul@openvz.org>
  22 */
  23
  24#include <linux/slab.h>
  25#include <linux/mm.h>
  26#include <linux/hugetlb.h>
  27#include <linux/shm.h>
  28#include <linux/init.h>
  29#include <linux/file.h>
  30#include <linux/mman.h>
  31#include <linux/shmem_fs.h>
  32#include <linux/security.h>
  33#include <linux/syscalls.h>
  34#include <linux/audit.h>
  35#include <linux/capability.h>
  36#include <linux/ptrace.h>
  37#include <linux/seq_file.h>
  38#include <linux/rwsem.h>
  39#include <linux/nsproxy.h>
  40#include <linux/mount.h>
  41#include <linux/ipc_namespace.h>
  42
  43#include <asm/uaccess.h>
  44
  45#include "util.h"
  46
  47struct shm_file_data {
  48	int id;
  49	struct ipc_namespace *ns;
  50	struct file *file;
  51	const struct vm_operations_struct *vm_ops;
  52};
  53
  54#define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
  55
  56static const struct file_operations shm_file_operations;
  57static const struct vm_operations_struct shm_vm_ops;
  58
  59#define shm_ids(ns)	((ns)->ids[IPC_SHM_IDS])
  60
  61#define shm_unlock(shp)			\
  62	ipc_unlock(&(shp)->shm_perm)
  63
  64static int newseg(struct ipc_namespace *, struct ipc_params *);
  65static void shm_open(struct vm_area_struct *vma);
  66static void shm_close(struct vm_area_struct *vma);
  67static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
  68#ifdef CONFIG_PROC_FS
  69static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
  70#endif
  71
  72void shm_init_ns(struct ipc_namespace *ns)
  73{
  74	ns->shm_ctlmax = SHMMAX;
  75	ns->shm_ctlall = SHMALL;
  76	ns->shm_ctlmni = SHMMNI;
  77	ns->shm_rmid_forced = 0;
  78	ns->shm_tot = 0;
  79	ipc_init_ids(&shm_ids(ns));
  80}
  81
  82/*
  83 * Called with shm_ids.rw_mutex (writer) and the shp structure locked.
  84 * Only shm_ids.rw_mutex remains locked on exit.
  85 */
  86static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
  87{
  88	struct shmid_kernel *shp;
  89	shp = container_of(ipcp, struct shmid_kernel, shm_perm);
  90
  91	if (shp->shm_nattch){
  92		shp->shm_perm.mode |= SHM_DEST;
  93		/* Do not find it any more */
  94		shp->shm_perm.key = IPC_PRIVATE;
  95		shm_unlock(shp);
  96	} else
  97		shm_destroy(ns, shp);
  98}
  99
 100#ifdef CONFIG_IPC_NS
 101void shm_exit_ns(struct ipc_namespace *ns)
 102{
 103	free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
 104	idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
 105}
 106#endif
 107
 108static int __init ipc_ns_init(void)
 109{
 110	shm_init_ns(&init_ipc_ns);
 111	return 0;
 112}
 113
 114pure_initcall(ipc_ns_init);
 115
 116void __init shm_init (void)
 117{
 118	ipc_init_proc_interface("sysvipc/shm",
 119#if BITS_PER_LONG <= 32
 120				"       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime        rss       swap\n",
 121#else
 122				"       key      shmid perms                  size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime                   rss                  swap\n",
 123#endif
 124				IPC_SHM_IDS, sysvipc_shm_proc_show);
 125}
 126
 127/*
 128 * shm_lock_(check_) routines are called in the paths where the rw_mutex
 129 * is not necessarily held.
 130 */
 131static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
 132{
 133	struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
 134
 135	if (IS_ERR(ipcp))
 136		return (struct shmid_kernel *)ipcp;
 137
 138	return container_of(ipcp, struct shmid_kernel, shm_perm);
 139}
 140
 141static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
 142{
 143	rcu_read_lock();
 144	spin_lock(&ipcp->shm_perm.lock);
 145}
 146
 147static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
 148						int id)
 149{
 150	struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id);
 151
 152	if (IS_ERR(ipcp))
 153		return (struct shmid_kernel *)ipcp;
 154
 155	return container_of(ipcp, struct shmid_kernel, shm_perm);
 156}
 157
 158static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
 159{
 160	ipc_rmid(&shm_ids(ns), &s->shm_perm);
 161}
 162
 163
 164/* This is called by fork, once for every shm attach. */
 165static void shm_open(struct vm_area_struct *vma)
 166{
 167	struct file *file = vma->vm_file;
 168	struct shm_file_data *sfd = shm_file_data(file);
 169	struct shmid_kernel *shp;
 170
 171	shp = shm_lock(sfd->ns, sfd->id);
 172	BUG_ON(IS_ERR(shp));
 173	shp->shm_atim = get_seconds();
 174	shp->shm_lprid = task_tgid_vnr(current);
 175	shp->shm_nattch++;
 176	shm_unlock(shp);
 177}
 178
 179/*
 180 * shm_destroy - free the struct shmid_kernel
 181 *
 182 * @ns: namespace
 183 * @shp: struct to free
 184 *
 185 * It has to be called with shp and shm_ids.rw_mutex (writer) locked,
 186 * but returns with shp unlocked and freed.
 187 */
 188static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
 189{
 190	ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
 191	shm_rmid(ns, shp);
 192	shm_unlock(shp);
 193	if (!is_file_hugepages(shp->shm_file))
 194		shmem_lock(shp->shm_file, 0, shp->mlock_user);
 195	else if (shp->mlock_user)
 196		user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
 197						shp->mlock_user);
 198	fput (shp->shm_file);
 199	security_shm_free(shp);
 200	ipc_rcu_putref(shp);
 201}
 202
 203/*
 204 * shm_may_destroy - identifies whether shm segment should be destroyed now
 205 *
 206 * Returns true if and only if there are no active users of the segment and
 207 * one of the following is true:
 208 *
 209 * 1) shmctl(id, IPC_RMID, NULL) was called for this shp
 210 *
 211 * 2) sysctl kernel.shm_rmid_forced is set to 1.
 212 */
 213static bool shm_may_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
 214{
 215	return (shp->shm_nattch == 0) &&
 216	       (ns->shm_rmid_forced ||
 217		(shp->shm_perm.mode & SHM_DEST));
 218}
 219
 220/*
 221 * remove the attach descriptor vma.
 222 * free memory for segment if it is marked destroyed.
 223 * The descriptor has already been removed from the current->mm->mmap list
 224 * and will later be kfree()d.
 225 */
 226static void shm_close(struct vm_area_struct *vma)
 227{
 228	struct file * file = vma->vm_file;
 229	struct shm_file_data *sfd = shm_file_data(file);
 230	struct shmid_kernel *shp;
 231	struct ipc_namespace *ns = sfd->ns;
 232
 233	down_write(&shm_ids(ns).rw_mutex);
 234	/* remove from the list of attaches of the shm segment */
 235	shp = shm_lock(ns, sfd->id);
 236	BUG_ON(IS_ERR(shp));
 237	shp->shm_lprid = task_tgid_vnr(current);
 238	shp->shm_dtim = get_seconds();
 239	shp->shm_nattch--;
 240	if (shm_may_destroy(ns, shp))
 241		shm_destroy(ns, shp);
 242	else
 243		shm_unlock(shp);
 244	up_write(&shm_ids(ns).rw_mutex);
 245}
 246
 247/* Called with ns->shm_ids(ns).rw_mutex locked */
 248static int shm_try_destroy_current(int id, void *p, void *data)
 249{
 250	struct ipc_namespace *ns = data;
 251	struct kern_ipc_perm *ipcp = p;
 252	struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 253
 254	if (shp->shm_creator != current)
 255		return 0;
 256
 257	/*
 258	 * Mark it as orphaned to destroy the segment when
 259	 * kernel.shm_rmid_forced is changed.
 260	 * It is noop if the following shm_may_destroy() returns true.
 261	 */
 262	shp->shm_creator = NULL;
 263
 264	/*
 265	 * Don't even try to destroy it.  If shm_rmid_forced=0 and IPC_RMID
 266	 * is not set, it shouldn't be deleted here.
 267	 */
 268	if (!ns->shm_rmid_forced)
 269		return 0;
 270
 271	if (shm_may_destroy(ns, shp)) {
 272		shm_lock_by_ptr(shp);
 273		shm_destroy(ns, shp);
 274	}
 275	return 0;
 276}
 277
 278/* Called with ns->shm_ids(ns).rw_mutex locked */
 279static int shm_try_destroy_orphaned(int id, void *p, void *data)
 280{
 281	struct ipc_namespace *ns = data;
 282	struct kern_ipc_perm *ipcp = p;
 283	struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 284
 285	/*
 286	 * We want to destroy segments without users and with already
 287	 * exit'ed originating process.
 288	 *
 289	 * As shp->* are changed under rw_mutex, it's safe to skip shp locking.
 290	 */
 291	if (shp->shm_creator != NULL)
 292		return 0;
 293
 294	if (shm_may_destroy(ns, shp)) {
 295		shm_lock_by_ptr(shp);
 296		shm_destroy(ns, shp);
 297	}
 298	return 0;
 299}
 300
 301void shm_destroy_orphaned(struct ipc_namespace *ns)
 302{
 303	down_write(&shm_ids(ns).rw_mutex);
 304	if (shm_ids(ns).in_use)
 305		idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns);
 306	up_write(&shm_ids(ns).rw_mutex);
 307}
 308
 309
 310void exit_shm(struct task_struct *task)
 311{
 312	struct ipc_namespace *ns = task->nsproxy->ipc_ns;
 313
 314	if (shm_ids(ns).in_use == 0)
 315		return;
 316
 317	/* Destroy all already created segments, but not mapped yet */
 318	down_write(&shm_ids(ns).rw_mutex);
 319	if (shm_ids(ns).in_use)
 320		idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_current, ns);
 321	up_write(&shm_ids(ns).rw_mutex);
 322}
 323
 324static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 325{
 326	struct file *file = vma->vm_file;
 327	struct shm_file_data *sfd = shm_file_data(file);
 328
 329	return sfd->vm_ops->fault(vma, vmf);
 330}
 331
 332#ifdef CONFIG_NUMA
 333static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
 334{
 335	struct file *file = vma->vm_file;
 336	struct shm_file_data *sfd = shm_file_data(file);
 337	int err = 0;
 338	if (sfd->vm_ops->set_policy)
 339		err = sfd->vm_ops->set_policy(vma, new);
 340	return err;
 341}
 342
 343static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
 344					unsigned long addr)
 345{
 346	struct file *file = vma->vm_file;
 347	struct shm_file_data *sfd = shm_file_data(file);
 348	struct mempolicy *pol = NULL;
 349
 350	if (sfd->vm_ops->get_policy)
 351		pol = sfd->vm_ops->get_policy(vma, addr);
 352	else if (vma->vm_policy)
 353		pol = vma->vm_policy;
 354
 355	return pol;
 356}
 357#endif
 358
 359static int shm_mmap(struct file * file, struct vm_area_struct * vma)
 360{
 361	struct shm_file_data *sfd = shm_file_data(file);
 362	int ret;
 363
 364	ret = sfd->file->f_op->mmap(sfd->file, vma);
 365	if (ret != 0)
 366		return ret;
 367	sfd->vm_ops = vma->vm_ops;
 368#ifdef CONFIG_MMU
 369	BUG_ON(!sfd->vm_ops->fault);
 370#endif
 371	vma->vm_ops = &shm_vm_ops;
 372	shm_open(vma);
 373
 374	return ret;
 375}
 376
 377static int shm_release(struct inode *ino, struct file *file)
 378{
 379	struct shm_file_data *sfd = shm_file_data(file);
 380
 381	put_ipc_ns(sfd->ns);
 382	shm_file_data(file) = NULL;
 383	kfree(sfd);
 384	return 0;
 385}
 386
 387static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
 388{
 389	struct shm_file_data *sfd = shm_file_data(file);
 390
 391	if (!sfd->file->f_op->fsync)
 392		return -EINVAL;
 393	return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
 394}
 395
 396static unsigned long shm_get_unmapped_area(struct file *file,
 397	unsigned long addr, unsigned long len, unsigned long pgoff,
 398	unsigned long flags)
 399{
 400	struct shm_file_data *sfd = shm_file_data(file);
 401	return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
 402						pgoff, flags);
 403}
 404
 405static const struct file_operations shm_file_operations = {
 406	.mmap		= shm_mmap,
 407	.fsync		= shm_fsync,
 408	.release	= shm_release,
 409#ifndef CONFIG_MMU
 410	.get_unmapped_area	= shm_get_unmapped_area,
 411#endif
 412	.llseek		= noop_llseek,
 413};
 414
 415static const struct file_operations shm_file_operations_huge = {
 416	.mmap		= shm_mmap,
 417	.fsync		= shm_fsync,
 418	.release	= shm_release,
 419	.get_unmapped_area	= shm_get_unmapped_area,
 420	.llseek		= noop_llseek,
 421};
 422
 423int is_file_shm_hugepages(struct file *file)
 424{
 425	return file->f_op == &shm_file_operations_huge;
 426}
 427
 428static const struct vm_operations_struct shm_vm_ops = {
 429	.open	= shm_open,	/* callback for a new vm-area open */
 430	.close	= shm_close,	/* callback for when the vm-area is released */
 431	.fault	= shm_fault,
 432#if defined(CONFIG_NUMA)
 433	.set_policy = shm_set_policy,
 434	.get_policy = shm_get_policy,
 435#endif
 436};
 437
 438/**
 439 * newseg - Create a new shared memory segment
 440 * @ns: namespace
 441 * @params: ptr to the structure that contains key, size and shmflg
 442 *
 443 * Called with shm_ids.rw_mutex held as a writer.
 444 */
 445
 446static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
 447{
 448	key_t key = params->key;
 449	int shmflg = params->flg;
 450	size_t size = params->u.size;
 451	int error;
 452	struct shmid_kernel *shp;
 453	int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
 454	struct file * file;
 455	char name[13];
 456	int id;
 457	vm_flags_t acctflag = 0;
 458
 459	if (size < SHMMIN || size > ns->shm_ctlmax)
 460		return -EINVAL;
 461
 462	if (ns->shm_tot + numpages > ns->shm_ctlall)
 463		return -ENOSPC;
 464
 465	shp = ipc_rcu_alloc(sizeof(*shp));
 466	if (!shp)
 467		return -ENOMEM;
 468
 469	shp->shm_perm.key = key;
 470	shp->shm_perm.mode = (shmflg & S_IRWXUGO);
 471	shp->mlock_user = NULL;
 472
 473	shp->shm_perm.security = NULL;
 474	error = security_shm_alloc(shp);
 475	if (error) {
 476		ipc_rcu_putref(shp);
 477		return error;
 478	}
 479
 480	sprintf (name, "SYSV%08x", key);
 481	if (shmflg & SHM_HUGETLB) {
 482		/* hugetlb_file_setup applies strict accounting */
 483		if (shmflg & SHM_NORESERVE)
 484			acctflag = VM_NORESERVE;
 485		file = hugetlb_file_setup(name, size, acctflag,
 486					&shp->mlock_user, HUGETLB_SHMFS_INODE);
 487	} else {
 488		/*
 489		 * Do not allow no accounting for OVERCOMMIT_NEVER, even
 490	 	 * if it's asked for.
 491		 */
 492		if  ((shmflg & SHM_NORESERVE) &&
 493				sysctl_overcommit_memory != OVERCOMMIT_NEVER)
 494			acctflag = VM_NORESERVE;
 495		file = shmem_file_setup(name, size, acctflag);
 496	}
 497	error = PTR_ERR(file);
 498	if (IS_ERR(file))
 499		goto no_file;
 500
 501	id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
 502	if (id < 0) {
 503		error = id;
 504		goto no_id;
 505	}
 506
 507	shp->shm_cprid = task_tgid_vnr(current);
 508	shp->shm_lprid = 0;
 509	shp->shm_atim = shp->shm_dtim = 0;
 510	shp->shm_ctim = get_seconds();
 511	shp->shm_segsz = size;
 512	shp->shm_nattch = 0;
 513	shp->shm_file = file;
 514	shp->shm_creator = current;
 515	/*
 516	 * shmid gets reported as "inode#" in /proc/pid/maps.
 517	 * proc-ps tools use this. Changing this will break them.
 518	 */
 519	file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
 520
 521	ns->shm_tot += numpages;
 522	error = shp->shm_perm.id;
 523	shm_unlock(shp);
 524	return error;
 525
 526no_id:
 527	if (is_file_hugepages(file) && shp->mlock_user)
 528		user_shm_unlock(size, shp->mlock_user);
 529	fput(file);
 530no_file:
 531	security_shm_free(shp);
 532	ipc_rcu_putref(shp);
 533	return error;
 534}
 535
 536/*
 537 * Called with shm_ids.rw_mutex and ipcp locked.
 538 */
 539static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
 540{
 541	struct shmid_kernel *shp;
 542
 543	shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 544	return security_shm_associate(shp, shmflg);
 545}
 546
 547/*
 548 * Called with shm_ids.rw_mutex and ipcp locked.
 549 */
 550static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
 551				struct ipc_params *params)
 552{
 553	struct shmid_kernel *shp;
 554
 555	shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 556	if (shp->shm_segsz < params->u.size)
 557		return -EINVAL;
 558
 559	return 0;
 560}
 561
 562SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
 563{
 564	struct ipc_namespace *ns;
 565	struct ipc_ops shm_ops;
 566	struct ipc_params shm_params;
 567
 568	ns = current->nsproxy->ipc_ns;
 569
 570	shm_ops.getnew = newseg;
 571	shm_ops.associate = shm_security;
 572	shm_ops.more_checks = shm_more_checks;
 573
 574	shm_params.key = key;
 575	shm_params.flg = shmflg;
 576	shm_params.u.size = size;
 577
 578	return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
 579}
 580
 581static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
 582{
 583	switch(version) {
 584	case IPC_64:
 585		return copy_to_user(buf, in, sizeof(*in));
 586	case IPC_OLD:
 587	    {
 588		struct shmid_ds out;
 589
 590		memset(&out, 0, sizeof(out));
 591		ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
 592		out.shm_segsz	= in->shm_segsz;
 593		out.shm_atime	= in->shm_atime;
 594		out.shm_dtime	= in->shm_dtime;
 595		out.shm_ctime	= in->shm_ctime;
 596		out.shm_cpid	= in->shm_cpid;
 597		out.shm_lpid	= in->shm_lpid;
 598		out.shm_nattch	= in->shm_nattch;
 599
 600		return copy_to_user(buf, &out, sizeof(out));
 601	    }
 602	default:
 603		return -EINVAL;
 604	}
 605}
 606
 607static inline unsigned long
 608copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
 609{
 610	switch(version) {
 611	case IPC_64:
 612		if (copy_from_user(out, buf, sizeof(*out)))
 613			return -EFAULT;
 614		return 0;
 615	case IPC_OLD:
 616	    {
 617		struct shmid_ds tbuf_old;
 618
 619		if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
 620			return -EFAULT;
 621
 622		out->shm_perm.uid	= tbuf_old.shm_perm.uid;
 623		out->shm_perm.gid	= tbuf_old.shm_perm.gid;
 624		out->shm_perm.mode	= tbuf_old.shm_perm.mode;
 625
 626		return 0;
 627	    }
 628	default:
 629		return -EINVAL;
 630	}
 631}
 632
 633static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
 634{
 635	switch(version) {
 636	case IPC_64:
 637		return copy_to_user(buf, in, sizeof(*in));
 638	case IPC_OLD:
 639	    {
 640		struct shminfo out;
 641
 642		if(in->shmmax > INT_MAX)
 643			out.shmmax = INT_MAX;
 644		else
 645			out.shmmax = (int)in->shmmax;
 646
 647		out.shmmin	= in->shmmin;
 648		out.shmmni	= in->shmmni;
 649		out.shmseg	= in->shmseg;
 650		out.shmall	= in->shmall; 
 651
 652		return copy_to_user(buf, &out, sizeof(out));
 653	    }
 654	default:
 655		return -EINVAL;
 656	}
 657}
 658
 659/*
 660 * Calculate and add used RSS and swap pages of a shm.
 661 * Called with shm_ids.rw_mutex held as a reader
 662 */
 663static void shm_add_rss_swap(struct shmid_kernel *shp,
 664	unsigned long *rss_add, unsigned long *swp_add)
 665{
 666	struct inode *inode;
 667
 668	inode = shp->shm_file->f_path.dentry->d_inode;
 669
 670	if (is_file_hugepages(shp->shm_file)) {
 671		struct address_space *mapping = inode->i_mapping;
 672		struct hstate *h = hstate_file(shp->shm_file);
 673		*rss_add += pages_per_huge_page(h) * mapping->nrpages;
 674	} else {
 675#ifdef CONFIG_SHMEM
 676		struct shmem_inode_info *info = SHMEM_I(inode);
 677		spin_lock(&info->lock);
 678		*rss_add += inode->i_mapping->nrpages;
 679		*swp_add += info->swapped;
 680		spin_unlock(&info->lock);
 681#else
 682		*rss_add += inode->i_mapping->nrpages;
 683#endif
 684	}
 685}
 686
 687/*
 688 * Called with shm_ids.rw_mutex held as a reader
 689 */
 690static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
 691		unsigned long *swp)
 692{
 693	int next_id;
 694	int total, in_use;
 695
 696	*rss = 0;
 697	*swp = 0;
 698
 699	in_use = shm_ids(ns).in_use;
 700
 701	for (total = 0, next_id = 0; total < in_use; next_id++) {
 702		struct kern_ipc_perm *ipc;
 703		struct shmid_kernel *shp;
 704
 705		ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
 706		if (ipc == NULL)
 707			continue;
 708		shp = container_of(ipc, struct shmid_kernel, shm_perm);
 709
 710		shm_add_rss_swap(shp, rss, swp);
 711
 712		total++;
 713	}
 714}
 715
 716/*
 717 * This function handles some shmctl commands which require the rw_mutex
 718 * to be held in write mode.
 719 * NOTE: no locks must be held, the rw_mutex is taken inside this function.
 720 */
 721static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
 722		       struct shmid_ds __user *buf, int version)
 723{
 724	struct kern_ipc_perm *ipcp;
 725	struct shmid64_ds shmid64;
 726	struct shmid_kernel *shp;
 727	int err;
 728
 729	if (cmd == IPC_SET) {
 730		if (copy_shmid_from_user(&shmid64, buf, version))
 731			return -EFAULT;
 732	}
 733
 734	ipcp = ipcctl_pre_down(ns, &shm_ids(ns), shmid, cmd,
 735			       &shmid64.shm_perm, 0);
 736	if (IS_ERR(ipcp))
 737		return PTR_ERR(ipcp);
 738
 739	shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 740
 741	err = security_shm_shmctl(shp, cmd);
 742	if (err)
 743		goto out_unlock;
 744	switch (cmd) {
 745	case IPC_RMID:
 746		do_shm_rmid(ns, ipcp);
 747		goto out_up;
 748	case IPC_SET:
 749		ipc_update_perm(&shmid64.shm_perm, ipcp);
 750		shp->shm_ctim = get_seconds();
 751		break;
 752	default:
 753		err = -EINVAL;
 754	}
 755out_unlock:
 756	shm_unlock(shp);
 757out_up:
 758	up_write(&shm_ids(ns).rw_mutex);
 759	return err;
 760}
 761
 762SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
 763{
 764	struct shmid_kernel *shp;
 765	int err, version;
 766	struct ipc_namespace *ns;
 767
 768	if (cmd < 0 || shmid < 0) {
 769		err = -EINVAL;
 770		goto out;
 771	}
 772
 773	version = ipc_parse_version(&cmd);
 774	ns = current->nsproxy->ipc_ns;
 775
 776	switch (cmd) { /* replace with proc interface ? */
 777	case IPC_INFO:
 778	{
 779		struct shminfo64 shminfo;
 780
 781		err = security_shm_shmctl(NULL, cmd);
 782		if (err)
 783			return err;
 784
 785		memset(&shminfo, 0, sizeof(shminfo));
 786		shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
 787		shminfo.shmmax = ns->shm_ctlmax;
 788		shminfo.shmall = ns->shm_ctlall;
 789
 790		shminfo.shmmin = SHMMIN;
 791		if(copy_shminfo_to_user (buf, &shminfo, version))
 792			return -EFAULT;
 793
 794		down_read(&shm_ids(ns).rw_mutex);
 795		err = ipc_get_maxid(&shm_ids(ns));
 796		up_read(&shm_ids(ns).rw_mutex);
 797
 798		if(err<0)
 799			err = 0;
 800		goto out;
 801	}
 802	case SHM_INFO:
 803	{
 804		struct shm_info shm_info;
 805
 806		err = security_shm_shmctl(NULL, cmd);
 807		if (err)
 808			return err;
 809
 810		memset(&shm_info, 0, sizeof(shm_info));
 811		down_read(&shm_ids(ns).rw_mutex);
 812		shm_info.used_ids = shm_ids(ns).in_use;
 813		shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
 814		shm_info.shm_tot = ns->shm_tot;
 815		shm_info.swap_attempts = 0;
 816		shm_info.swap_successes = 0;
 817		err = ipc_get_maxid(&shm_ids(ns));
 818		up_read(&shm_ids(ns).rw_mutex);
 819		if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {
 820			err = -EFAULT;
 821			goto out;
 822		}
 823
 824		err = err < 0 ? 0 : err;
 825		goto out;
 826	}
 827	case SHM_STAT:
 828	case IPC_STAT:
 829	{
 830		struct shmid64_ds tbuf;
 831		int result;
 832
 833		if (cmd == SHM_STAT) {
 834			shp = shm_lock(ns, shmid);
 835			if (IS_ERR(shp)) {
 836				err = PTR_ERR(shp);
 837				goto out;
 838			}
 839			result = shp->shm_perm.id;
 840		} else {
 841			shp = shm_lock_check(ns, shmid);
 842			if (IS_ERR(shp)) {
 843				err = PTR_ERR(shp);
 844				goto out;
 845			}
 846			result = 0;
 847		}
 848		err = -EACCES;
 849		if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
 850			goto out_unlock;
 851		err = security_shm_shmctl(shp, cmd);
 852		if (err)
 853			goto out_unlock;
 854		memset(&tbuf, 0, sizeof(tbuf));
 855		kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
 856		tbuf.shm_segsz	= shp->shm_segsz;
 857		tbuf.shm_atime	= shp->shm_atim;
 858		tbuf.shm_dtime	= shp->shm_dtim;
 859		tbuf.shm_ctime	= shp->shm_ctim;
 860		tbuf.shm_cpid	= shp->shm_cprid;
 861		tbuf.shm_lpid	= shp->shm_lprid;
 862		tbuf.shm_nattch	= shp->shm_nattch;
 863		shm_unlock(shp);
 864		if(copy_shmid_to_user (buf, &tbuf, version))
 865			err = -EFAULT;
 866		else
 867			err = result;
 868		goto out;
 869	}
 870	case SHM_LOCK:
 871	case SHM_UNLOCK:
 872	{
 873		struct file *uninitialized_var(shm_file);
 874
 875		lru_add_drain_all();  /* drain pagevecs to lru lists */
 876
 877		shp = shm_lock_check(ns, shmid);
 878		if (IS_ERR(shp)) {
 879			err = PTR_ERR(shp);
 880			goto out;
 881		}
 882
 883		audit_ipc_obj(&(shp->shm_perm));
 884
 885		if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
 886			uid_t euid = current_euid();
 887			err = -EPERM;
 888			if (euid != shp->shm_perm.uid &&
 889			    euid != shp->shm_perm.cuid)
 890				goto out_unlock;
 891			if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK))
 892				goto out_unlock;
 893		}
 894
 895		err = security_shm_shmctl(shp, cmd);
 896		if (err)
 897			goto out_unlock;
 898		
 899		if(cmd==SHM_LOCK) {
 900			struct user_struct *user = current_user();
 901			if (!is_file_hugepages(shp->shm_file)) {
 902				err = shmem_lock(shp->shm_file, 1, user);
 903				if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
 904					shp->shm_perm.mode |= SHM_LOCKED;
 905					shp->mlock_user = user;
 906				}
 907			}
 908		} else if (!is_file_hugepages(shp->shm_file)) {
 909			shmem_lock(shp->shm_file, 0, shp->mlock_user);
 910			shp->shm_perm.mode &= ~SHM_LOCKED;
 911			shp->mlock_user = NULL;
 912		}
 913		shm_unlock(shp);
 914		goto out;
 915	}
 916	case IPC_RMID:
 917	case IPC_SET:
 918		err = shmctl_down(ns, shmid, cmd, buf, version);
 919		return err;
 920	default:
 921		return -EINVAL;
 922	}
 923
 924out_unlock:
 925	shm_unlock(shp);
 926out:
 927	return err;
 928}
 929
 930/*
 931 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
 932 *
 933 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
 934 * "raddr" thing points to kernel space, and there has to be a wrapper around
 935 * this.
 936 */
 937long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
 938{
 939	struct shmid_kernel *shp;
 940	unsigned long addr;
 941	unsigned long size;
 942	struct file * file;
 943	int    err;
 944	unsigned long flags;
 945	unsigned long prot;
 946	int acc_mode;
 947	unsigned long user_addr;
 948	struct ipc_namespace *ns;
 949	struct shm_file_data *sfd;
 950	struct path path;
 951	fmode_t f_mode;
 952
 953	err = -EINVAL;
 954	if (shmid < 0)
 955		goto out;
 956	else if ((addr = (ulong)shmaddr)) {
 957		if (addr & (SHMLBA-1)) {
 958			if (shmflg & SHM_RND)
 959				addr &= ~(SHMLBA-1);	   /* round down */
 960			else
 961#ifndef __ARCH_FORCE_SHMLBA
 962				if (addr & ~PAGE_MASK)
 963#endif
 964					goto out;
 965		}
 966		flags = MAP_SHARED | MAP_FIXED;
 967	} else {
 968		if ((shmflg & SHM_REMAP))
 969			goto out;
 970
 971		flags = MAP_SHARED;
 972	}
 973
 974	if (shmflg & SHM_RDONLY) {
 975		prot = PROT_READ;
 976		acc_mode = S_IRUGO;
 977		f_mode = FMODE_READ;
 978	} else {
 979		prot = PROT_READ | PROT_WRITE;
 980		acc_mode = S_IRUGO | S_IWUGO;
 981		f_mode = FMODE_READ | FMODE_WRITE;
 982	}
 983	if (shmflg & SHM_EXEC) {
 984		prot |= PROT_EXEC;
 985		acc_mode |= S_IXUGO;
 986	}
 987
 988	/*
 989	 * We cannot rely on the fs check since SYSV IPC does have an
 990	 * additional creator id...
 991	 */
 992	ns = current->nsproxy->ipc_ns;
 993	shp = shm_lock_check(ns, shmid);
 994	if (IS_ERR(shp)) {
 995		err = PTR_ERR(shp);
 996		goto out;
 997	}
 998
 999	err = -EACCES;
1000	if (ipcperms(ns, &shp->shm_perm, acc_mode))
1001		goto out_unlock;
1002
1003	err = security_shm_shmat(shp, shmaddr, shmflg);
1004	if (err)
1005		goto out_unlock;
1006
1007	path = shp->shm_file->f_path;
1008	path_get(&path);
1009	shp->shm_nattch++;
1010	size = i_size_read(path.dentry->d_inode);
1011	shm_unlock(shp);
1012
1013	err = -ENOMEM;
1014	sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
1015	if (!sfd)
1016		goto out_put_dentry;
1017
1018	file = alloc_file(&path, f_mode,
1019			  is_file_hugepages(shp->shm_file) ?
1020				&shm_file_operations_huge :
1021				&shm_file_operations);
1022	if (!file)
1023		goto out_free;
1024
1025	file->private_data = sfd;
1026	file->f_mapping = shp->shm_file->f_mapping;
1027	sfd->id = shp->shm_perm.id;
1028	sfd->ns = get_ipc_ns(ns);
1029	sfd->file = shp->shm_file;
1030	sfd->vm_ops = NULL;
1031
1032	down_write(&current->mm->mmap_sem);
1033	if (addr && !(shmflg & SHM_REMAP)) {
1034		err = -EINVAL;
1035		if (find_vma_intersection(current->mm, addr, addr + size))
1036			goto invalid;
1037		/*
1038		 * If shm segment goes below stack, make sure there is some
1039		 * space left for the stack to grow (at least 4 pages).
1040		 */
1041		if (addr < current->mm->start_stack &&
1042		    addr > current->mm->start_stack - size - PAGE_SIZE * 5)
1043			goto invalid;
1044	}
1045		
1046	user_addr = do_mmap (file, addr, size, prot, flags, 0);
1047	*raddr = user_addr;
1048	err = 0;
1049	if (IS_ERR_VALUE(user_addr))
1050		err = (long)user_addr;
1051invalid:
1052	up_write(&current->mm->mmap_sem);
1053
1054	fput(file);
1055
1056out_nattch:
1057	down_write(&shm_ids(ns).rw_mutex);
1058	shp = shm_lock(ns, shmid);
1059	BUG_ON(IS_ERR(shp));
1060	shp->shm_nattch--;
1061	if (shm_may_destroy(ns, shp))
1062		shm_destroy(ns, shp);
1063	else
1064		shm_unlock(shp);
1065	up_write(&shm_ids(ns).rw_mutex);
1066
1067out:
1068	return err;
1069
1070out_unlock:
1071	shm_unlock(shp);
1072	goto out;
1073
1074out_free:
1075	kfree(sfd);
1076out_put_dentry:
1077	path_put(&path);
1078	goto out_nattch;
1079}
1080
1081SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
1082{
1083	unsigned long ret;
1084	long err;
1085
1086	err = do_shmat(shmid, shmaddr, shmflg, &ret);
1087	if (err)
1088		return err;
1089	force_successful_syscall_return();
1090	return (long)ret;
1091}
1092
1093/*
1094 * detach and kill segment if marked destroyed.
1095 * The work is done in shm_close.
1096 */
1097SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
1098{
1099	struct mm_struct *mm = current->mm;
1100	struct vm_area_struct *vma;
1101	unsigned long addr = (unsigned long)shmaddr;
1102	int retval = -EINVAL;
1103#ifdef CONFIG_MMU
1104	loff_t size = 0;
1105	struct vm_area_struct *next;
1106#endif
1107
1108	if (addr & ~PAGE_MASK)
1109		return retval;
1110
1111	down_write(&mm->mmap_sem);
1112
1113	/*
1114	 * This function tries to be smart and unmap shm segments that
1115	 * were modified by partial mlock or munmap calls:
1116	 * - It first determines the size of the shm segment that should be
1117	 *   unmapped: It searches for a vma that is backed by shm and that
1118	 *   started at address shmaddr. It records it's size and then unmaps
1119	 *   it.
1120	 * - Then it unmaps all shm vmas that started at shmaddr and that
1121	 *   are within the initially determined size.
1122	 * Errors from do_munmap are ignored: the function only fails if
1123	 * it's called with invalid parameters or if it's called to unmap
1124	 * a part of a vma. Both calls in this function are for full vmas,
1125	 * the parameters are directly copied from the vma itself and always
1126	 * valid - therefore do_munmap cannot fail. (famous last words?)
1127	 */
1128	/*
1129	 * If it had been mremap()'d, the starting address would not
1130	 * match the usual checks anyway. So assume all vma's are
1131	 * above the starting address given.
1132	 */
1133	vma = find_vma(mm, addr);
1134
1135#ifdef CONFIG_MMU
1136	while (vma) {
1137		next = vma->vm_next;
1138
1139		/*
1140		 * Check if the starting address would match, i.e. it's
1141		 * a fragment created by mprotect() and/or munmap(), or it
1142		 * otherwise it starts at this address with no hassles.
1143		 */
1144		if ((vma->vm_ops == &shm_vm_ops) &&
1145			(vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1146
1147
1148			size = vma->vm_file->f_path.dentry->d_inode->i_size;
1149			do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1150			/*
1151			 * We discovered the size of the shm segment, so
1152			 * break out of here and fall through to the next
1153			 * loop that uses the size information to stop
1154			 * searching for matching vma's.
1155			 */
1156			retval = 0;
1157			vma = next;
1158			break;
1159		}
1160		vma = next;
1161	}
1162
1163	/*
1164	 * We need look no further than the maximum address a fragment
1165	 * could possibly have landed at. Also cast things to loff_t to
1166	 * prevent overflows and make comparisons vs. equal-width types.
1167	 */
1168	size = PAGE_ALIGN(size);
1169	while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1170		next = vma->vm_next;
1171
1172		/* finding a matching vma now does not alter retval */
1173		if ((vma->vm_ops == &shm_vm_ops) &&
1174			(vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1175
1176			do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1177		vma = next;
1178	}
1179
1180#else /* CONFIG_MMU */
1181	/* under NOMMU conditions, the exact address to be destroyed must be
1182	 * given */
1183	retval = -EINVAL;
1184	if (vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
1185		do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1186		retval = 0;
1187	}
1188
1189#endif
1190
1191	up_write(&mm->mmap_sem);
1192	return retval;
1193}
1194
1195#ifdef CONFIG_PROC_FS
1196static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1197{
1198	struct shmid_kernel *shp = it;
1199	unsigned long rss = 0, swp = 0;
1200
1201	shm_add_rss_swap(shp, &rss, &swp);
1202
1203#if BITS_PER_LONG <= 32
1204#define SIZE_SPEC "%10lu"
1205#else
1206#define SIZE_SPEC "%21lu"
1207#endif
1208
1209	return seq_printf(s,
1210			  "%10d %10d  %4o " SIZE_SPEC " %5u %5u  "
1211			  "%5lu %5u %5u %5u %5u %10lu %10lu %10lu "
1212			  SIZE_SPEC " " SIZE_SPEC "\n",
1213			  shp->shm_perm.key,
1214			  shp->shm_perm.id,
1215			  shp->shm_perm.mode,
1216			  shp->shm_segsz,
1217			  shp->shm_cprid,
1218			  shp->shm_lprid,
1219			  shp->shm_nattch,
1220			  shp->shm_perm.uid,
1221			  shp->shm_perm.gid,
1222			  shp->shm_perm.cuid,
1223			  shp->shm_perm.cgid,
1224			  shp->shm_atim,
1225			  shp->shm_dtim,
1226			  shp->shm_ctim,
1227			  rss * PAGE_SIZE,
1228			  swp * PAGE_SIZE);
1229}
1230#endif