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                         *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
 581                 } else {
 582                         struct shmem_inode_info *info = SHMEM_I(inode);
 583                         spin_lock(&info->lock);
 584                         *rss += inode->i_mapping->nrpages;
 585                         *swp += info->swapped;
 586                         spin_unlock(&info->lock);
 587                 }
 588
 589                 total++;
 590         }
 591 }
 592
 593 /*
 594  * This function handles some shmctl commands which require the rw_mutex
 595  * to be held in write mode.
 596  * NOTE: no locks must be held, the rw_mutex is taken inside this function.
 597  */
 598 static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
 599                        struct shmid_ds __user *buf, int version)
 600 {
 601         struct kern_ipc_perm *ipcp;
 602         struct shmid64_ds shmid64;
 603         struct shmid_kernel *shp;
 604         int err;
 605
 606         if (cmd == IPC_SET) {
 607                 if (copy_shmid_from_user(&shmid64, buf, version))
 608                         return -EFAULT;
 609         }
 610
 611         ipcp = ipcctl_pre_down(&shm_ids(ns), shmid, cmd, &shmid64.shm_perm, 0);
 612         if (IS_ERR(ipcp))
 613                 return PTR_ERR(ipcp);
 614
 615         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 616
 617         err = security_shm_shmctl(shp, cmd);
 618         if (err)
 619                 goto out_unlock;
 620         switch (cmd) {
 621         case IPC_RMID:
 622                 do_shm_rmid(ns, ipcp);
 623                 goto out_up;
 624         case IPC_SET:
 625                 ipc_update_perm(&shmid64.shm_perm, ipcp);
 626                 shp->shm_ctim = get_seconds();
 627                 break;
 628         default:
 629                 err = -EINVAL;
 630         }
 631 out_unlock:
 632         shm_unlock(shp);
 633 out_up:
 634         up_write(&shm_ids(ns).rw_mutex);
 635         return err;
 636 }
 637
 638 asmlinkage long sys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf)
 639 {
 640         struct shmid_kernel *shp;
 641         int err, version;
 642         struct ipc_namespace *ns;
 643
 644         if (cmd < 0 || shmid < 0) {
 645                 err = -EINVAL;
 646                 goto out;
 647         }
 648
 649         version = ipc_parse_version(&cmd);
 650         ns = current->nsproxy->ipc_ns;
 651
 652         switch (cmd) { /* replace with proc interface ? */
 653         case IPC_INFO:
 654         {
 655                 struct shminfo64 shminfo;
 656
 657                 err = security_shm_shmctl(NULL, cmd);
 658                 if (err)
 659                         return err;
 660
 661                 memset(&shminfo,0,sizeof(shminfo));
 662                 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
 663                 shminfo.shmmax = ns->shm_ctlmax;
 664                 shminfo.shmall = ns->shm_ctlall;
 665
 666                 shminfo.shmmin = SHMMIN;
 667                 if(copy_shminfo_to_user (buf, &shminfo, version))
 668                         return -EFAULT;
 669
 670                 down_read(&shm_ids(ns).rw_mutex);
 671                 err = ipc_get_maxid(&shm_ids(ns));
 672                 up_read(&shm_ids(ns).rw_mutex);
 673
 674                 if(err<0)
 675                         err = 0;
 676                 goto out;
 677         }
 678         case SHM_INFO:
 679         {
 680                 struct shm_info shm_info;
 681
 682                 err = security_shm_shmctl(NULL, cmd);
 683                 if (err)
 684                         return err;
 685
 686                 memset(&shm_info,0,sizeof(shm_info));
 687                 down_read(&shm_ids(ns).rw_mutex);
 688                 shm_info.used_ids = shm_ids(ns).in_use;
 689                 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
 690                 shm_info.shm_tot = ns->shm_tot;
 691                 shm_info.swap_attempts = 0;
 692                 shm_info.swap_successes = 0;
 693                 err = ipc_get_maxid(&shm_ids(ns));
 694                 up_read(&shm_ids(ns).rw_mutex);
 695                 if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
 696                         err = -EFAULT;
 697                         goto out;
 698                 }
 699
 700                 err = err < 0 ? 0 : err;
 701                 goto out;
 702         }
 703         case SHM_STAT:
 704         case IPC_STAT:
 705         {
 706                 struct shmid64_ds tbuf;
 707                 int result;
 708
 709                 if (!buf) {
 710                         err = -EFAULT;
 711                         goto out;
 712                 }
 713
 714                 if (cmd == SHM_STAT) {
 715                         shp = shm_lock(ns, shmid);
 716                         if (IS_ERR(shp)) {
 717                                 err = PTR_ERR(shp);
 718                                 goto out;
 719                         }
 720                         result = shp->shm_perm.id;
 721                 } else {
 722                         shp = shm_lock_check(ns, shmid);
 723                         if (IS_ERR(shp)) {
 724                                 err = PTR_ERR(shp);
 725                                 goto out;
 726                         }
 727                         result = 0;
 728                 }
 729                 err=-EACCES;
 730                 if (ipcperms (&shp->shm_perm, S_IRUGO))
 731                         goto out_unlock;
 732                 err = security_shm_shmctl(shp, cmd);
 733                 if (err)
 734                         goto out_unlock;
 735                 memset(&tbuf, 0, sizeof(tbuf));
 736                 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
 737                 tbuf.shm_segsz  = shp->shm_segsz;
 738                 tbuf.shm_atime  = shp->shm_atim;
 739                 tbuf.shm_dtime  = shp->shm_dtim;
 740                 tbuf.shm_ctime  = shp->shm_ctim;
 741                 tbuf.shm_cpid   = shp->shm_cprid;
 742                 tbuf.shm_lpid   = shp->shm_lprid;
 743                 tbuf.shm_nattch = shp->shm_nattch;
 744                 shm_unlock(shp);
 745                 if(copy_shmid_to_user (buf, &tbuf, version))
 746                         err = -EFAULT;
 747                 else
 748                         err = result;
 749                 goto out;
 750         }
 751         case SHM_LOCK:
 752         case SHM_UNLOCK:
 753         {
 754                 shp = shm_lock_check(ns, shmid);
 755                 if (IS_ERR(shp)) {
 756                         err = PTR_ERR(shp);
 757                         goto out;
 758                 }
 759
 760                 err = audit_ipc_obj(&(shp->shm_perm));
 761                 if (err)
 762                         goto out_unlock;
 763
 764                 if (!capable(CAP_IPC_LOCK)) {
 765                         err = -EPERM;
 766                         if (current->euid != shp->shm_perm.uid &&
 767                             current->euid != shp->shm_perm.cuid)
 768                                 goto out_unlock;
 769                         if (cmd == SHM_LOCK &&
 770                             !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
 771                                 goto out_unlock;
 772                 }
 773
 774                 err = security_shm_shmctl(shp, cmd);
 775                 if (err)
 776                         goto out_unlock;
 777
 778                 if(cmd==SHM_LOCK) {
 779                         struct user_struct * user = current->user;
 780                         if (!is_file_hugepages(shp->shm_file)) {
 781                                 err = shmem_lock(shp->shm_file, 1, user);
 782                                 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
 783                                         shp->shm_perm.mode |= SHM_LOCKED;
 784                                         shp->mlock_user = user;
 785                                 }
 786                         }
 787                 } else if (!is_file_hugepages(shp->shm_file)) {
 788                         shmem_lock(shp->shm_file, 0, shp->mlock_user);
 789                         shp->shm_perm.mode &= ~SHM_LOCKED;
 790                         shp->mlock_user = NULL;
 791                 }
 792                 shm_unlock(shp);
 793                 goto out;
 794         }
 795         case IPC_RMID:
 796         case IPC_SET:
 797                 err = shmctl_down(ns, shmid, cmd, buf, version);
 798                 return err;
 799         default:
 800                 return -EINVAL;
 801         }
 802
 803 out_unlock:
 804         shm_unlock(shp);
 805 out:
 806         return err;
 807 }
 808
 809 /*
 810  * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
 811  *
 812  * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
 813  * "raddr" thing points to kernel space, and there has to be a wrapper around
 814  * this.
 815  */
 816 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
 817 {
 818         struct shmid_kernel *shp;
 819         unsigned long addr;
 820         unsigned long size;
 821         struct file * file;
 822         int    err;
 823         unsigned long flags;
 824         unsigned long prot;
 825         int acc_mode;
 826         unsigned long user_addr;
 827         struct ipc_namespace *ns;
 828         struct shm_file_data *sfd;
 829         struct path path;
 830         mode_t f_mode;
 831
 832         err = -EINVAL;
 833         if (shmid < 0)
 834                 goto out;
 835         else if ((addr = (ulong)shmaddr)) {
 836                 if (addr & (SHMLBA-1)) {
 837                         if (shmflg & SHM_RND)
 838                                 addr &= ~(SHMLBA-1);       /* round down */
 839                         else
 840 #ifndef __ARCH_FORCE_SHMLBA
 841                                 if (addr & ~PAGE_MASK)
 842 #endif
 843                                         goto out;
 844                 }
 845                 flags = MAP_SHARED | MAP_FIXED;
 846         } else {
 847                 if ((shmflg & SHM_REMAP))
 848                         goto out;
 849
 850                 flags = MAP_SHARED;
 851         }
 852
 853         if (shmflg & SHM_RDONLY) {
 854                 prot = PROT_READ;
 855                 acc_mode = S_IRUGO;
 856                 f_mode = FMODE_READ;
 857         } else {
 858                 prot = PROT_READ | PROT_WRITE;
 859                 acc_mode = S_IRUGO | S_IWUGO;
 860                 f_mode = FMODE_READ | FMODE_WRITE;
 861         }
 862         if (shmflg & SHM_EXEC) {
 863                 prot |= PROT_EXEC;
 864                 acc_mode |= S_IXUGO;
 865         }
 866
 867         /*
 868          * We cannot rely on the fs check since SYSV IPC does have an
 869          * additional creator id...
 870          */
 871         ns = current->nsproxy->ipc_ns;
 872         shp = shm_lock_check(ns, shmid);
 873         if (IS_ERR(shp)) {
 874                 err = PTR_ERR(shp);
 875                 goto out;
 876         }
 877
 878         err = -EACCES;
 879         if (ipcperms(&shp->shm_perm, acc_mode))
 880                 goto out_unlock;
 881
 882         err = security_shm_shmat(shp, shmaddr, shmflg);
 883         if (err)
 884                 goto out_unlock;
 885
 886         path.dentry = dget(shp->shm_file->f_path.dentry);
 887         path.mnt    = shp->shm_file->f_path.mnt;
 888         shp->shm_nattch++;
 889         size = i_size_read(path.dentry->d_inode);
 890         shm_unlock(shp);
 891
 892         err = -ENOMEM;
 893         sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
 894         if (!sfd)
 895                 goto out_put_dentry;
 896
 897         file = alloc_file(path.mnt, path.dentry, f_mode, &shm_file_operations);
 898         if (!file)
 899                 goto out_free;
 900
 901         file->private_data = sfd;
 902         file->f_mapping = shp->shm_file->f_mapping;
 903         sfd->id = shp->shm_perm.id;
 904         sfd->ns = get_ipc_ns(ns);
 905         sfd->file = shp->shm_file;
 906         sfd->vm_ops = NULL;
 907
 908         down_write(&current->mm->mmap_sem);
 909         if (addr && !(shmflg & SHM_REMAP)) {
 910                 err = -EINVAL;
 911                 if (find_vma_intersection(current->mm, addr, addr + size))
 912                         goto invalid;
 913                 /*
 914                  * If shm segment goes below stack, make sure there is some
 915                  * space left for the stack to grow (at least 4 pages).
 916                  */
 917                 if (addr < current->mm->start_stack &&
 918                     addr > current->mm->start_stack - size - PAGE_SIZE * 5)
 919                         goto invalid;
 920         }
 921
 922         user_addr = do_mmap (file, addr, size, prot, flags, 0);
 923         *raddr = user_addr;
 924         err = 0;
 925         if (IS_ERR_VALUE(user_addr))
 926                 err = (long)user_addr;
 927 invalid:
 928         up_write(&current->mm->mmap_sem);
 929
 930         fput(file);
 931
 932 out_nattch:
 933         down_write(&shm_ids(ns).rw_mutex);
 934         shp = shm_lock_down(ns, shmid);
 935         BUG_ON(IS_ERR(shp));
 936         shp->shm_nattch--;
 937         if(shp->shm_nattch == 0 &&
 938            shp->shm_perm.mode & SHM_DEST)
 939                 shm_destroy(ns, shp);
 940         else
 941                 shm_unlock(shp);
 942         up_write(&shm_ids(ns).rw_mutex);
 943
 944 out:
 945         return err;
 946
 947 out_unlock:
 948         shm_unlock(shp);
 949         goto out;
 950
 951 out_free:
 952         kfree(sfd);
 953 out_put_dentry:
 954         dput(path.dentry);
 955         goto out_nattch;
 956 }
 957
 958 asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
 959 {
 960         unsigned long ret;
 961         long err;
 962
 963         err = do_shmat(shmid, shmaddr, shmflg, &ret);
 964         if (err)
 965                 return err;
 966         force_successful_syscall_return();
 967         return (long)ret;
 968 }
 969
 970 /*
 971  * detach and kill segment if marked destroyed.
 972  * The work is done in shm_close.
 973  */
 974 asmlinkage long sys_shmdt(char __user *shmaddr)
 975 {
 976         struct mm_struct *mm = current->mm;
 977         struct vm_area_struct *vma, *next;
 978         unsigned long addr = (unsigned long)shmaddr;
 979         loff_t size = 0;
 980         int retval = -EINVAL;
 981
 982         if (addr & ~PAGE_MASK)
 983                 return retval;
 984
 985         down_write(&mm->mmap_sem);
 986
 987         /*
 988          * This function tries to be smart and unmap shm segments that
 989          * were modified by partial mlock or munmap calls:
 990          * - It first determines the size of the shm segment that should be
 991          *   unmapped: It searches for a vma that is backed by shm and that
 992          *   started at address shmaddr. It records it's size and then unmaps
 993          *   it.
 994          * - Then it unmaps all shm vmas that started at shmaddr and that
 995          *   are within the initially determined size.
 996          * Errors from do_munmap are ignored: the function only fails if
 997          * it's called with invalid parameters or if it's called to unmap
 998          * a part of a vma. Both calls in this function are for full vmas,
 999          * the parameters are directly copied from the vma itself and always
1000          * valid - therefore do_munmap cannot fail. (famous last words?)
1001          */
1002         /*
1003          * If it had been mremap()'d, the starting address would not
1004          * match the usual checks anyway. So assume all vma's are
1005          * above the starting address given.
1006          */
1007         vma = find_vma(mm, addr);
1008
1009         while (vma) {
1010                 next = vma->vm_next;
1011
1012                 /*
1013                  * Check if the starting address would match, i.e. it's
1014                  * a fragment created by mprotect() and/or munmap(), or it
1015                  * otherwise it starts at this address with no hassles.
1016                  */
1017                 if ((vma->vm_ops == &shm_vm_ops) &&
1018                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1019
1020
1021                         size = vma->vm_file->f_path.dentry->d_inode->i_size;
1022                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1023                         /*
1024                          * We discovered the size of the shm segment, so
1025                          * break out of here and fall through to the next
1026                          * loop that uses the size information to stop
1027                          * searching for matching vma's.
1028                          */
1029                         retval = 0;
1030                         vma = next;
1031                         break;
1032                 }
1033                 vma = next;
1034         }
1035
1036         /*
1037          * We need look no further than the maximum address a fragment
1038          * could possibly have landed at. Also cast things to loff_t to
1039          * prevent overflows and make comparisions vs. equal-width types.
1040          */
1041         size = PAGE_ALIGN(size);
1042         while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1043                 next = vma->vm_next;
1044
1045                 /* finding a matching vma now does not alter retval */
1046                 if ((vma->vm_ops == &shm_vm_ops) &&
1047                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1048
1049                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1050                 vma = next;
1051         }
1052
1053         up_write(&mm->mmap_sem);
1054         return retval;
1055 }
1056
1057 #ifdef CONFIG_PROC_FS
1058 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1059 {
1060         struct shmid_kernel *shp = it;
1061
1062 #if BITS_PER_LONG <= 32
1063 #define SIZE_SPEC "%10lu"
1064 #else
1065 #define SIZE_SPEC "%21lu"
1066 #endif
1067
1068         return seq_printf(s,
1069                           "%10d %10d  %4o " SIZE_SPEC " %5u %5u  "
1070                           "%5lu %5u %5u %5u %5u %10lu %10lu %10lu\n",
1071                           shp->shm_perm.key,
1072                           shp->shm_perm.id,
1073                           shp->shm_perm.mode,
1074                           shp->shm_segsz,
1075                           shp->shm_cprid,
1076                           shp->shm_lprid,
1077                           shp->shm_nattch,
1078                           shp->shm_perm.uid,
1079                           shp->shm_perm.gid,
1080                           shp->shm_perm.cuid,
1081                           shp->shm_perm.cgid,
1082                           shp->shm_atim,
1083                           shp->shm_dtim,
1084                           shp->shm_ctim);
1085 }
1086 #endif