ipc/shm.c

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