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/mutex.h>
  39 #include <linux/nsproxy.h>
  40 #include <linux/mount.h>
  41
  42 #include <asm/uaccess.h>
  43
  44 #include "util.h"
  45
  46 struct shm_file_data {
  47         int id;
  48         struct ipc_namespace *ns;
  49         struct file *file;
  50         const struct vm_operations_struct *vm_ops;
  51 };
  52
  53 #define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
  54
  55 static const struct file_operations shm_file_operations;
  56 static struct vm_operations_struct shm_vm_ops;
  57
  58 static struct ipc_ids init_shm_ids;
  59
  60 #define shm_ids(ns)     (*((ns)->ids[IPC_SHM_IDS]))
  61
  62 #define shm_lock(ns, id)                \
  63         ((struct shmid_kernel*)ipc_lock(&shm_ids(ns),id))
  64 #define shm_unlock(shp)                 \
  65         ipc_unlock(&(shp)->shm_perm)
  66 #define shm_get(ns, id)                 \
  67         ((struct shmid_kernel*)ipc_get(&shm_ids(ns),id))
  68 #define shm_buildid(ns, id, seq)        \
  69         ipc_buildid(&shm_ids(ns), id, seq)
  70
  71 static int newseg (struct ipc_namespace *ns, key_t key,
  72                 int shmflg, size_t size);
  73 static void shm_open(struct vm_area_struct *vma);
  74 static void shm_close(struct vm_area_struct *vma);
  75 static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
  76 #ifdef CONFIG_PROC_FS
  77 static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
  78 #endif
  79
  80 static void __ipc_init __shm_init_ns(struct ipc_namespace *ns, struct ipc_ids *ids)
  81 {
  82         ns->ids[IPC_SHM_IDS] = ids;
  83         ns->shm_ctlmax = SHMMAX;
  84         ns->shm_ctlall = SHMALL;
  85         ns->shm_ctlmni = SHMMNI;
  86         ns->shm_tot = 0;
  87         ipc_init_ids(ids, 1);
  88 }
  89
  90 static void do_shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *shp)
  91 {
  92         if (shp->shm_nattch){
  93                 shp->shm_perm.mode |= SHM_DEST;
  94                 /* Do not find it any more */
  95                 shp->shm_perm.key = IPC_PRIVATE;
  96                 shm_unlock(shp);
  97         } else
  98                 shm_destroy(ns, shp);
  99 }
 100
 101 #ifdef CONFIG_IPC_NS
 102 int shm_init_ns(struct ipc_namespace *ns)
 103 {
 104         struct ipc_ids *ids;
 105
 106         ids = kmalloc(sizeof(struct ipc_ids), GFP_KERNEL);
 107         if (ids == NULL)
 108                 return -ENOMEM;
 109
 110         __shm_init_ns(ns, ids);
 111         return 0;
 112 }
 113
 114 void shm_exit_ns(struct ipc_namespace *ns)
 115 {
 116         int i;
 117         struct shmid_kernel *shp;
 118
 119         mutex_lock(&shm_ids(ns).mutex);
 120         for (i = 0; i <= shm_ids(ns).max_id; i++) {
 121                 shp = shm_lock(ns, i);
 122                 if (shp == NULL)
 123                         continue;
 124
 125                 do_shm_rmid(ns, shp);
 126         }
 127         mutex_unlock(&shm_ids(ns).mutex);
 128
 129         ipc_fini_ids(ns->ids[IPC_SHM_IDS]);
 130         kfree(ns->ids[IPC_SHM_IDS]);
 131         ns->ids[IPC_SHM_IDS] = NULL;
 132 }
 133 #endif
 134
 135 void __init shm_init (void)
 136 {
 137         __shm_init_ns(&init_ipc_ns, &init_shm_ids);
 138         ipc_init_proc_interface("sysvipc/shm",
 139                                 "       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime\n",
 140                                 IPC_SHM_IDS, sysvipc_shm_proc_show);
 141 }
 142
 143 static inline int shm_checkid(struct ipc_namespace *ns,
 144                 struct shmid_kernel *s, int id)
 145 {
 146         if (ipc_checkid(&shm_ids(ns), &s->shm_perm, id))
 147                 return -EIDRM;
 148         return 0;
 149 }
 150
 151 static inline struct shmid_kernel *shm_rmid(struct ipc_namespace *ns, int id)
 152 {
 153         return (struct shmid_kernel *)ipc_rmid(&shm_ids(ns), id);
 154 }
 155
 156 static inline int shm_addid(struct ipc_namespace *ns, struct shmid_kernel *shp)
 157 {
 158         return ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
 159 }
 160
 161
 162
 163 /* This is called by fork, once for every shm attach. */
 164 static void shm_open(struct vm_area_struct *vma)
 165 {
 166         struct file *file = vma->vm_file;
 167         struct shm_file_data *sfd = shm_file_data(file);
 168         struct shmid_kernel *shp;
 169
 170         shp = shm_lock(sfd->ns, sfd->id);
 171         BUG_ON(!shp);
 172         shp->shm_atim = get_seconds();
 173         shp->shm_lprid = current->tgid;
 174         shp->shm_nattch++;
 175         shm_unlock(shp);
 176 }
 177
 178 /*
 179  * shm_destroy - free the struct shmid_kernel
 180  *
 181  * @shp: struct to free
 182  *
 183  * It has to be called with shp and shm_ids.mutex locked,
 184  * but returns with shp unlocked and freed.
 185  */
 186 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
 187 {
 188         ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
 189         shm_rmid(ns, shp->id);
 190         shm_unlock(shp);
 191         if (!is_file_hugepages(shp->shm_file))
 192                 shmem_lock(shp->shm_file, 0, shp->mlock_user);
 193         else
 194                 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
 195                                                 shp->mlock_user);
 196         fput (shp->shm_file);
 197         security_shm_free(shp);
 198         ipc_rcu_putref(shp);
 199 }
 200
 201 /*
 202  * remove the attach descriptor vma.
 203  * free memory for segment if it is marked destroyed.
 204  * The descriptor has already been removed from the current->mm->mmap list
 205  * and will later be kfree()d.
 206  */
 207 static void shm_close(struct vm_area_struct *vma)
 208 {
 209         struct file * file = vma->vm_file;
 210         struct shm_file_data *sfd = shm_file_data(file);
 211         struct shmid_kernel *shp;
 212         struct ipc_namespace *ns = sfd->ns;
 213
 214         mutex_lock(&shm_ids(ns).mutex);
 215         /* remove from the list of attaches of the shm segment */
 216         shp = shm_lock(ns, sfd->id);
 217         BUG_ON(!shp);
 218         shp->shm_lprid = current->tgid;
 219         shp->shm_dtim = get_seconds();
 220         shp->shm_nattch--;
 221         if(shp->shm_nattch == 0 &&
 222            shp->shm_perm.mode & SHM_DEST)
 223                 shm_destroy(ns, shp);
 224         else
 225                 shm_unlock(shp);
 226         mutex_unlock(&shm_ids(ns).mutex);
 227 }
 228
 229 static struct page *shm_nopage(struct vm_area_struct *vma,
 230                                unsigned long address, int *type)
 231 {
 232         struct file *file = vma->vm_file;
 233         struct shm_file_data *sfd = shm_file_data(file);
 234
 235         return sfd->vm_ops->nopage(vma, address, type);
 236 }
 237
 238 #ifdef CONFIG_NUMA
 239 int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
 240 {
 241         struct file *file = vma->vm_file;
 242         struct shm_file_data *sfd = shm_file_data(file);
 243         int err = 0;
 244         if (sfd->vm_ops->set_policy)
 245                 err = sfd->vm_ops->set_policy(vma, new);
 246         return err;
 247 }
 248
 249 struct mempolicy *shm_get_policy(struct vm_area_struct *vma, unsigned long addr)
 250 {
 251         struct file *file = vma->vm_file;
 252         struct shm_file_data *sfd = shm_file_data(file);
 253         struct mempolicy *pol = NULL;
 254
 255         if (sfd->vm_ops->get_policy)
 256                 pol = sfd->vm_ops->get_policy(vma, addr);
 257         else
 258                 pol = vma->vm_policy;
 259         return pol;
 260 }
 261 #endif
 262
 263 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
 264 {
 265         struct shm_file_data *sfd = shm_file_data(file);
 266         int ret;
 267
 268         ret = sfd->file->f_op->mmap(sfd->file, vma);
 269         if (ret != 0)
 270                 return ret;
 271         sfd->vm_ops = vma->vm_ops;
 272         vma->vm_ops = &shm_vm_ops;
 273         shm_open(vma);
 274
 275         return ret;
 276 }
 277
 278 static int shm_release(struct inode *ino, struct file *file)
 279 {
 280         struct shm_file_data *sfd = shm_file_data(file);
 281
 282         put_ipc_ns(sfd->ns);
 283         shm_file_data(file) = NULL;
 284         kfree(sfd);
 285         return 0;
 286 }
 287
 288 static int shm_fsync(struct file *file, struct dentry *dentry, int datasync)
 289 {
 290         int (*fsync) (struct file *, struct dentry *, int datasync);
 291         struct shm_file_data *sfd = shm_file_data(file);
 292         int ret = -EINVAL;
 293
 294         fsync = sfd->file->f_op->fsync;
 295         if (fsync)
 296                 ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync);
 297         return ret;
 298 }
 299
 300 static unsigned long shm_get_unmapped_area(struct file *file,
 301         unsigned long addr, unsigned long len, unsigned long pgoff,
 302         unsigned long flags)
 303 {
 304         struct shm_file_data *sfd = shm_file_data(file);
 305         return get_unmapped_area(sfd->file, addr, len, pgoff, flags);
 306 }
 307
 308 int is_file_shm_hugepages(struct file *file)
 309 {
 310         int ret = 0;
 311
 312         if (file->f_op == &shm_file_operations) {
 313                 struct shm_file_data *sfd;
 314                 sfd = shm_file_data(file);
 315                 ret = is_file_hugepages(sfd->file);
 316         }
 317         return ret;
 318 }
 319
 320 static const struct file_operations shm_file_operations = {
 321         .mmap           = shm_mmap,
 322         .fsync          = shm_fsync,
 323         .release        = shm_release,
 324         .get_unmapped_area      = shm_get_unmapped_area,
 325 };
 326
 327 static struct vm_operations_struct shm_vm_ops = {
 328         .open   = shm_open,     /* callback for a new vm-area open */
 329         .close  = shm_close,    /* callback for when the vm-area is released */
 330         .nopage = shm_nopage,
 331 #if defined(CONFIG_NUMA)
 332         .set_policy = shm_set_policy,
 333         .get_policy = shm_get_policy,
 334 #endif
 335 };
 336
 337 static int newseg (struct ipc_namespace *ns, key_t key, int shmflg, size_t size)
 338 {
 339         int error;
 340         struct shmid_kernel *shp;
 341         int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
 342         struct file * file;
 343         char name[13];
 344         int id;
 345
 346         if (size < SHMMIN || size > ns->shm_ctlmax)
 347                 return -EINVAL;
 348
 349         if (ns->shm_tot + numpages > ns->shm_ctlall)
 350                 return -ENOSPC;
 351
 352         shp = ipc_rcu_alloc(sizeof(*shp));
 353         if (!shp)
 354                 return -ENOMEM;
 355
 356         shp->shm_perm.key = key;
 357         shp->shm_perm.mode = (shmflg & S_IRWXUGO);
 358         shp->mlock_user = NULL;
 359
 360         shp->shm_perm.security = NULL;
 361         error = security_shm_alloc(shp);
 362         if (error) {
 363                 ipc_rcu_putref(shp);
 364                 return error;
 365         }
 366
 367         if (shmflg & SHM_HUGETLB) {
 368                 /* hugetlb_zero_setup takes care of mlock user accounting */
 369                 file = hugetlb_zero_setup(size);
 370                 shp->mlock_user = current->user;
 371         } else {
 372                 int acctflag = VM_ACCOUNT;
 373                 /*
 374                  * Do not allow no accounting for OVERCOMMIT_NEVER, even
 375                  * if it's asked for.
 376                  */
 377                 if  ((shmflg & SHM_NORESERVE) &&
 378                                 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
 379                         acctflag = 0;
 380                 sprintf (name, "SYSV%08x", key);
 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         error = -ENOSPC;
 388         id = shm_addid(ns, shp);
 389         if(id == -1)
 390                 goto no_id;
 391
 392         shp->shm_cprid = current->tgid;
 393         shp->shm_lprid = 0;
 394         shp->shm_atim = shp->shm_dtim = 0;
 395         shp->shm_ctim = get_seconds();
 396         shp->shm_segsz = size;
 397         shp->shm_nattch = 0;
 398         shp->id = shm_buildid(ns, id, shp->shm_perm.seq);
 399         shp->shm_file = file;
 400
 401         ns->shm_tot += numpages;
 402         shm_unlock(shp);
 403         return shp->id;
 404
 405 no_id:
 406         fput(file);
 407 no_file:
 408         security_shm_free(shp);
 409         ipc_rcu_putref(shp);
 410         return error;
 411 }
 412
 413 asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
 414 {
 415         struct shmid_kernel *shp;
 416         int err, id = 0;
 417         struct ipc_namespace *ns;
 418
 419         ns = current->nsproxy->ipc_ns;
 420
 421         mutex_lock(&shm_ids(ns).mutex);
 422         if (key == IPC_PRIVATE) {
 423                 err = newseg(ns, key, shmflg, size);
 424         } else if ((id = ipc_findkey(&shm_ids(ns), key)) == -1) {
 425                 if (!(shmflg & IPC_CREAT))
 426                         err = -ENOENT;
 427                 else
 428                         err = newseg(ns, key, shmflg, size);
 429         } else if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL)) {
 430                 err = -EEXIST;
 431         } else {
 432                 shp = shm_lock(ns, id);
 433                 BUG_ON(shp==NULL);
 434                 if (shp->shm_segsz < size)
 435                         err = -EINVAL;
 436                 else if (ipcperms(&shp->shm_perm, shmflg))
 437                         err = -EACCES;
 438                 else {
 439                         int shmid = shm_buildid(ns, id, shp->shm_perm.seq);
 440                         err = security_shm_associate(shp, shmflg);
 441                         if (!err)
 442                                 err = shmid;
 443                 }
 444                 shm_unlock(shp);
 445         }
 446         mutex_unlock(&shm_ids(ns).mutex);
 447
 448         return err;
 449 }
 450
 451 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
 452 {
 453         switch(version) {
 454         case IPC_64:
 455                 return copy_to_user(buf, in, sizeof(*in));
 456         case IPC_OLD:
 457             {
 458                 struct shmid_ds out;
 459
 460                 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
 461                 out.shm_segsz   = in->shm_segsz;
 462                 out.shm_atime   = in->shm_atime;
 463                 out.shm_dtime   = in->shm_dtime;
 464                 out.shm_ctime   = in->shm_ctime;
 465                 out.shm_cpid    = in->shm_cpid;
 466                 out.shm_lpid    = in->shm_lpid;
 467                 out.shm_nattch  = in->shm_nattch;
 468
 469                 return copy_to_user(buf, &out, sizeof(out));
 470             }
 471         default:
 472                 return -EINVAL;
 473         }
 474 }
 475
 476 struct shm_setbuf {
 477         uid_t   uid;
 478         gid_t   gid;
 479         mode_t  mode;
 480 };
 481
 482 static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
 483 {
 484         switch(version) {
 485         case IPC_64:
 486             {
 487                 struct shmid64_ds tbuf;
 488
 489                 if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
 490                         return -EFAULT;
 491
 492                 out->uid        = tbuf.shm_perm.uid;
 493                 out->gid        = tbuf.shm_perm.gid;
 494                 out->mode       = tbuf.shm_perm.mode;
 495
 496                 return 0;
 497             }
 498         case IPC_OLD:
 499             {
 500                 struct shmid_ds tbuf_old;
 501
 502                 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
 503                         return -EFAULT;
 504
 505                 out->uid        = tbuf_old.shm_perm.uid;
 506                 out->gid        = tbuf_old.shm_perm.gid;
 507                 out->mode       = tbuf_old.shm_perm.mode;
 508
 509                 return 0;
 510             }
 511         default:
 512                 return -EINVAL;
 513         }
 514 }
 515
 516 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
 517 {
 518         switch(version) {
 519         case IPC_64:
 520                 return copy_to_user(buf, in, sizeof(*in));
 521         case IPC_OLD:
 522             {
 523                 struct shminfo out;
 524
 525                 if(in->shmmax > INT_MAX)
 526                         out.shmmax = INT_MAX;
 527                 else
 528                         out.shmmax = (int)in->shmmax;
 529
 530                 out.shmmin      = in->shmmin;
 531                 out.shmmni      = in->shmmni;
 532                 out.shmseg      = in->shmseg;
 533                 out.shmall      = in->shmall;
 534
 535                 return copy_to_user(buf, &out, sizeof(out));
 536             }
 537         default:
 538                 return -EINVAL;
 539         }
 540 }
 541
 542 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
 543                 unsigned long *swp)
 544 {
 545         int i;
 546
 547         *rss = 0;
 548         *swp = 0;
 549
 550         for (i = 0; i <= shm_ids(ns).max_id; i++) {
 551                 struct shmid_kernel *shp;
 552                 struct inode *inode;
 553
 554                 shp = shm_get(ns, i);
 555                 if(!shp)
 556                         continue;
 557
 558                 inode = shp->shm_file->f_path.dentry->d_inode;
 559
 560                 if (is_file_hugepages(shp->shm_file)) {
 561                         struct address_space *mapping = inode->i_mapping;
 562                         *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
 563                 } else {
 564                         struct shmem_inode_info *info = SHMEM_I(inode);
 565                         spin_lock(&info->lock);
 566                         *rss += inode->i_mapping->nrpages;
 567                         *swp += info->swapped;
 568                         spin_unlock(&info->lock);
 569                 }
 570         }
 571 }
 572
 573 asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
 574 {
 575         struct shm_setbuf setbuf;
 576         struct shmid_kernel *shp;
 577         int err, version;
 578         struct ipc_namespace *ns;
 579
 580         if (cmd < 0 || shmid < 0) {
 581                 err = -EINVAL;
 582                 goto out;
 583         }
 584
 585         version = ipc_parse_version(&cmd);
 586         ns = current->nsproxy->ipc_ns;
 587
 588         switch (cmd) { /* replace with proc interface ? */
 589         case IPC_INFO:
 590         {
 591                 struct shminfo64 shminfo;
 592
 593                 err = security_shm_shmctl(NULL, cmd);
 594                 if (err)
 595                         return err;
 596
 597                 memset(&shminfo,0,sizeof(shminfo));
 598                 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
 599                 shminfo.shmmax = ns->shm_ctlmax;
 600                 shminfo.shmall = ns->shm_ctlall;
 601
 602                 shminfo.shmmin = SHMMIN;
 603                 if(copy_shminfo_to_user (buf, &shminfo, version))
 604                         return -EFAULT;
 605                 /* reading a integer is always atomic */
 606                 err= shm_ids(ns).max_id;
 607                 if(err<0)
 608                         err = 0;
 609                 goto out;
 610         }
 611         case SHM_INFO:
 612         {
 613                 struct shm_info shm_info;
 614
 615                 err = security_shm_shmctl(NULL, cmd);
 616                 if (err)
 617                         return err;
 618
 619                 memset(&shm_info,0,sizeof(shm_info));
 620                 mutex_lock(&shm_ids(ns).mutex);
 621                 shm_info.used_ids = shm_ids(ns).in_use;
 622                 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
 623                 shm_info.shm_tot = ns->shm_tot;
 624                 shm_info.swap_attempts = 0;
 625                 shm_info.swap_successes = 0;
 626                 err = shm_ids(ns).max_id;
 627                 mutex_unlock(&shm_ids(ns).mutex);
 628                 if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
 629                         err = -EFAULT;
 630                         goto out;
 631                 }
 632
 633                 err = err < 0 ? 0 : err;
 634                 goto out;
 635         }
 636         case SHM_STAT:
 637         case IPC_STAT:
 638         {
 639                 struct shmid64_ds tbuf;
 640                 int result;
 641                 memset(&tbuf, 0, sizeof(tbuf));
 642                 shp = shm_lock(ns, shmid);
 643                 if(shp==NULL) {
 644                         err = -EINVAL;
 645                         goto out;
 646                 } else if(cmd==SHM_STAT) {
 647                         err = -EINVAL;
 648                         if (shmid > shm_ids(ns).max_id)
 649                                 goto out_unlock;
 650                         result = shm_buildid(ns, shmid, shp->shm_perm.seq);
 651                 } else {
 652                         err = shm_checkid(ns, shp,shmid);
 653                         if(err)
 654                                 goto out_unlock;
 655                         result = 0;
 656                 }
 657                 err=-EACCES;
 658                 if (ipcperms (&shp->shm_perm, S_IRUGO))
 659                         goto out_unlock;
 660                 err = security_shm_shmctl(shp, cmd);
 661                 if (err)
 662                         goto out_unlock;
 663                 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
 664                 tbuf.shm_segsz  = shp->shm_segsz;
 665                 tbuf.shm_atime  = shp->shm_atim;
 666                 tbuf.shm_dtime  = shp->shm_dtim;
 667                 tbuf.shm_ctime  = shp->shm_ctim;
 668                 tbuf.shm_cpid   = shp->shm_cprid;
 669                 tbuf.shm_lpid   = shp->shm_lprid;
 670                 tbuf.shm_nattch = shp->shm_nattch;
 671                 shm_unlock(shp);
 672                 if(copy_shmid_to_user (buf, &tbuf, version))
 673                         err = -EFAULT;
 674                 else
 675                         err = result;
 676                 goto out;
 677         }
 678         case SHM_LOCK:
 679         case SHM_UNLOCK:
 680         {
 681                 shp = shm_lock(ns, shmid);
 682                 if(shp==NULL) {
 683                         err = -EINVAL;
 684                         goto out;
 685                 }
 686                 err = shm_checkid(ns, shp,shmid);
 687                 if(err)
 688                         goto out_unlock;
 689
 690                 err = audit_ipc_obj(&(shp->shm_perm));
 691                 if (err)
 692                         goto out_unlock;
 693
 694                 if (!capable(CAP_IPC_LOCK)) {
 695                         err = -EPERM;
 696                         if (current->euid != shp->shm_perm.uid &&
 697                             current->euid != shp->shm_perm.cuid)
 698                                 goto out_unlock;
 699                         if (cmd == SHM_LOCK &&
 700                             !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
 701                                 goto out_unlock;
 702                 }
 703
 704                 err = security_shm_shmctl(shp, cmd);
 705                 if (err)
 706                         goto out_unlock;
 707
 708                 if(cmd==SHM_LOCK) {
 709                         struct user_struct * user = current->user;
 710                         if (!is_file_hugepages(shp->shm_file)) {
 711                                 err = shmem_lock(shp->shm_file, 1, user);
 712                                 if (!err) {
 713                                         shp->shm_perm.mode |= SHM_LOCKED;
 714                                         shp->mlock_user = user;
 715                                 }
 716                         }
 717                 } else if (!is_file_hugepages(shp->shm_file)) {
 718                         shmem_lock(shp->shm_file, 0, shp->mlock_user);
 719                         shp->shm_perm.mode &= ~SHM_LOCKED;
 720                         shp->mlock_user = NULL;
 721                 }
 722                 shm_unlock(shp);
 723                 goto out;
 724         }
 725         case IPC_RMID:
 726         {
 727                 /*
 728                  *      We cannot simply remove the file. The SVID states
 729                  *      that the block remains until the last person
 730                  *      detaches from it, then is deleted. A shmat() on
 731                  *      an RMID segment is legal in older Linux and if
 732                  *      we change it apps break...
 733                  *
 734                  *      Instead we set a destroyed flag, and then blow
 735                  *      the name away when the usage hits zero.
 736                  */
 737                 mutex_lock(&shm_ids(ns).mutex);
 738                 shp = shm_lock(ns, shmid);
 739                 err = -EINVAL;
 740                 if (shp == NULL)
 741                         goto out_up;
 742                 err = shm_checkid(ns, shp, shmid);
 743                 if(err)
 744                         goto out_unlock_up;
 745
 746                 err = audit_ipc_obj(&(shp->shm_perm));
 747                 if (err)
 748                         goto out_unlock_up;
 749
 750                 if (current->euid != shp->shm_perm.uid &&
 751                     current->euid != shp->shm_perm.cuid &&
 752                     !capable(CAP_SYS_ADMIN)) {
 753                         err=-EPERM;
 754                         goto out_unlock_up;
 755                 }
 756
 757                 err = security_shm_shmctl(shp, cmd);
 758                 if (err)
 759                         goto out_unlock_up;
 760
 761                 do_shm_rmid(ns, shp);
 762                 mutex_unlock(&shm_ids(ns).mutex);
 763                 goto out;
 764         }
 765
 766         case IPC_SET:
 767         {
 768                 if (copy_shmid_from_user (&setbuf, buf, version)) {
 769                         err = -EFAULT;
 770                         goto out;
 771                 }
 772                 mutex_lock(&shm_ids(ns).mutex);
 773                 shp = shm_lock(ns, shmid);
 774                 err=-EINVAL;
 775                 if(shp==NULL)
 776                         goto out_up;
 777                 err = shm_checkid(ns, shp,shmid);
 778                 if(err)
 779                         goto out_unlock_up;
 780                 err = audit_ipc_obj(&(shp->shm_perm));
 781                 if (err)
 782                         goto out_unlock_up;
 783                 err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode);
 784                 if (err)
 785                         goto out_unlock_up;
 786                 err=-EPERM;
 787                 if (current->euid != shp->shm_perm.uid &&
 788                     current->euid != shp->shm_perm.cuid &&
 789                     !capable(CAP_SYS_ADMIN)) {
 790                         goto out_unlock_up;
 791                 }
 792
 793                 err = security_shm_shmctl(shp, cmd);
 794                 if (err)
 795                         goto out_unlock_up;
 796
 797                 shp->shm_perm.uid = setbuf.uid;
 798                 shp->shm_perm.gid = setbuf.gid;
 799                 shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO)
 800                         | (setbuf.mode & S_IRWXUGO);
 801                 shp->shm_ctim = get_seconds();
 802                 break;
 803         }
 804
 805         default:
 806                 err = -EINVAL;
 807                 goto out;
 808         }
 809
 810         err = 0;
 811 out_unlock_up:
 812         shm_unlock(shp);
 813 out_up:
 814         mutex_unlock(&shm_ids(ns).mutex);
 815         goto out;
 816 out_unlock:
 817         shm_unlock(shp);
 818 out:
 819         return err;
 820 }
 821
 822 /*
 823  * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
 824  *
 825  * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
 826  * "raddr" thing points to kernel space, and there has to be a wrapper around
 827  * this.
 828  */
 829 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
 830 {
 831         struct shmid_kernel *shp;
 832         unsigned long addr;
 833         unsigned long size;
 834         struct file * file;
 835         int    err;
 836         unsigned long flags;
 837         unsigned long prot;
 838         int acc_mode;
 839         unsigned long user_addr;
 840         struct ipc_namespace *ns;
 841         struct shm_file_data *sfd;
 842         struct path path;
 843         mode_t f_mode;
 844
 845         err = -EINVAL;
 846         if (shmid < 0)
 847                 goto out;
 848         else if ((addr = (ulong)shmaddr)) {
 849                 if (addr & (SHMLBA-1)) {
 850                         if (shmflg & SHM_RND)
 851                                 addr &= ~(SHMLBA-1);       /* round down */
 852                         else
 853 #ifndef __ARCH_FORCE_SHMLBA
 854                                 if (addr & ~PAGE_MASK)
 855 #endif
 856                                         goto out;
 857                 }
 858                 flags = MAP_SHARED | MAP_FIXED;
 859         } else {
 860                 if ((shmflg & SHM_REMAP))
 861                         goto out;
 862
 863                 flags = MAP_SHARED;
 864         }
 865
 866         if (shmflg & SHM_RDONLY) {
 867                 prot = PROT_READ;
 868                 acc_mode = S_IRUGO;
 869                 f_mode = FMODE_READ;
 870         } else {
 871                 prot = PROT_READ | PROT_WRITE;
 872                 acc_mode = S_IRUGO | S_IWUGO;
 873                 f_mode = FMODE_READ | FMODE_WRITE;
 874         }
 875         if (shmflg & SHM_EXEC) {
 876                 prot |= PROT_EXEC;
 877                 acc_mode |= S_IXUGO;
 878         }
 879
 880         /*
 881          * We cannot rely on the fs check since SYSV IPC does have an
 882          * additional creator id...
 883          */
 884         ns = current->nsproxy->ipc_ns;
 885         shp = shm_lock(ns, shmid);
 886         if(shp == NULL)
 887                 goto out;
 888
 889         err = shm_checkid(ns, shp,shmid);
 890         if (err)
 891                 goto out_unlock;
 892
 893         err = -EACCES;
 894         if (ipcperms(&shp->shm_perm, acc_mode))
 895                 goto out_unlock;
 896
 897         err = security_shm_shmat(shp, shmaddr, shmflg);
 898         if (err)
 899                 goto out_unlock;
 900
 901         path.dentry = dget(shp->shm_file->f_path.dentry);
 902         path.mnt    = mntget(shp->shm_file->f_path.mnt);
 903         shp->shm_nattch++;
 904         size = i_size_read(path.dentry->d_inode);
 905         shm_unlock(shp);
 906
 907         err = -ENOMEM;
 908         sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
 909         if (!sfd)
 910                 goto out_put_path;
 911
 912         err = -ENOMEM;
 913         file = get_empty_filp();
 914         if (!file)
 915                 goto out_free;
 916
 917         file->f_op = &shm_file_operations;
 918         file->private_data = sfd;
 919         file->f_path = path;
 920         file->f_mapping = shp->shm_file->f_mapping;
 921         file->f_mode = f_mode;
 922         sfd->id = shp->id;
 923         sfd->ns = get_ipc_ns(ns);
 924         sfd->file = shp->shm_file;
 925         sfd->vm_ops = NULL;
 926
 927         down_write(&current->mm->mmap_sem);
 928         if (addr && !(shmflg & SHM_REMAP)) {
 929                 err = -EINVAL;
 930                 if (find_vma_intersection(current->mm, addr, addr + size))
 931                         goto invalid;
 932                 /*
 933                  * If shm segment goes below stack, make sure there is some
 934                  * space left for the stack to grow (at least 4 pages).
 935                  */
 936                 if (addr < current->mm->start_stack &&
 937                     addr > current->mm->start_stack - size - PAGE_SIZE * 5)
 938                         goto invalid;
 939         }
 940
 941         user_addr = do_mmap (file, addr, size, prot, flags, 0);
 942         *raddr = user_addr;
 943         err = 0;
 944         if (IS_ERR_VALUE(user_addr))
 945                 err = (long)user_addr;
 946 invalid:
 947         up_write(&current->mm->mmap_sem);
 948
 949         fput(file);
 950
 951 out_nattch:
 952         mutex_lock(&shm_ids(ns).mutex);
 953         shp = shm_lock(ns, shmid);
 954         BUG_ON(!shp);
 955         shp->shm_nattch--;
 956         if(shp->shm_nattch == 0 &&
 957            shp->shm_perm.mode & SHM_DEST)
 958                 shm_destroy(ns, shp);
 959         else
 960                 shm_unlock(shp);
 961         mutex_unlock(&shm_ids(ns).mutex);
 962
 963 out:
 964         return err;
 965
 966 out_unlock:
 967         shm_unlock(shp);
 968         goto out;
 969
 970 out_free:
 971         kfree(sfd);
 972 out_put_path:
 973         dput(path.dentry);
 974         mntput(path.mnt);
 975         goto out_nattch;
 976 }
 977
 978 asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
 979 {
 980         unsigned long ret;
 981         long err;
 982
 983         err = do_shmat(shmid, shmaddr, shmflg, &ret);
 984         if (err)
 985                 return err;
 986         force_successful_syscall_return();
 987         return (long)ret;
 988 }
 989
 990 /*
 991  * detach and kill segment if marked destroyed.
 992  * The work is done in shm_close.
 993  */
 994 asmlinkage long sys_shmdt(char __user *shmaddr)
 995 {
 996         struct mm_struct *mm = current->mm;
 997         struct vm_area_struct *vma, *next;
 998         unsigned long addr = (unsigned long)shmaddr;
 999         loff_t size = 0;
1000         int retval = -EINVAL;
1001
1002         if (addr & ~PAGE_MASK)
1003                 return retval;
1004
1005         down_write(&mm->mmap_sem);
1006
1007         /*
1008          * This function tries to be smart and unmap shm segments that
1009          * were modified by partial mlock or munmap calls:
1010          * - It first determines the size of the shm segment that should be
1011          *   unmapped: It searches for a vma that is backed by shm and that
1012          *   started at address shmaddr. It records it's size and then unmaps
1013          *   it.
1014          * - Then it unmaps all shm vmas that started at shmaddr and that
1015          *   are within the initially determined size.
1016          * Errors from do_munmap are ignored: the function only fails if
1017          * it's called with invalid parameters or if it's called to unmap
1018          * a part of a vma. Both calls in this function are for full vmas,
1019          * the parameters are directly copied from the vma itself and always
1020          * valid - therefore do_munmap cannot fail. (famous last words?)
1021          */
1022         /*
1023          * If it had been mremap()'d, the starting address would not
1024          * match the usual checks anyway. So assume all vma's are
1025          * above the starting address given.
1026          */
1027         vma = find_vma(mm, addr);
1028
1029         while (vma) {
1030                 next = vma->vm_next;
1031
1032                 /*
1033                  * Check if the starting address would match, i.e. it's
1034                  * a fragment created by mprotect() and/or munmap(), or it
1035                  * otherwise it starts at this address with no hassles.
1036                  */
1037                 if ((vma->vm_ops == &shm_vm_ops) &&
1038                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1039
1040
1041                         size = vma->vm_file->f_path.dentry->d_inode->i_size;
1042                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1043                         /*
1044                          * We discovered the size of the shm segment, so
1045                          * break out of here and fall through to the next
1046                          * loop that uses the size information to stop
1047                          * searching for matching vma's.
1048                          */
1049                         retval = 0;
1050                         vma = next;
1051                         break;
1052                 }
1053                 vma = next;
1054         }
1055
1056         /*
1057          * We need look no further than the maximum address a fragment
1058          * could possibly have landed at. Also cast things to loff_t to
1059          * prevent overflows and make comparisions vs. equal-width types.
1060          */
1061         size = PAGE_ALIGN(size);
1062         while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1063                 next = vma->vm_next;
1064
1065                 /* finding a matching vma now does not alter retval */
1066                 if ((vma->vm_ops == &shm_vm_ops) &&
1067                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1068
1069                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1070                 vma = next;
1071         }
1072
1073         up_write(&mm->mmap_sem);
1074         return retval;
1075 }
1076
1077 #ifdef CONFIG_PROC_FS
1078 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1079 {
1080         struct shmid_kernel *shp = it;
1081         char *format;
1082
1083 #define SMALL_STRING "%10d %10d  %4o %10u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1084 #define BIG_STRING   "%10d %10d  %4o %21u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1085
1086         if (sizeof(size_t) <= sizeof(int))
1087                 format = SMALL_STRING;
1088         else
1089                 format = BIG_STRING;
1090         return seq_printf(s, format,
1091                           shp->shm_perm.key,
1092                           shp->id,
1093                           shp->shm_perm.mode,
1094                           shp->shm_segsz,
1095                           shp->shm_cprid,
1096                           shp->shm_lprid,
1097                           shp->shm_nattch,
1098                           shp->shm_perm.uid,
1099                           shp->shm_perm.gid,
1100                           shp->shm_perm.cuid,
1101                           shp->shm_perm.cgid,
1102                           shp->shm_atim,
1103                           shp->shm_dtim,
1104                           shp->shm_ctim);
1105 }
1106 #endif