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