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   1 /*
   2  * linux/ipc/shm.c
   3  * Copyright (C) 1992, 1993 Krishna Balasubramanian
   4  *       Many improvements/fixes by Bruno Haible.
   5  * Replaced `struct shm_desc' by `struct vm_area_struct', July 1994.
   6  * Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli.
   7  *
   8  * /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
   9  * BIGMEM support, Andrea Arcangeli <andrea@suse.de>
  10  * SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr>
  11  * HIGHMEM support, Ingo Molnar <mingo@redhat.com>
  12  * Make shmmax, shmall, shmmni sysctl'able, Christoph Rohland <cr@sap.com>
  13  * Shared /dev/zero support, Kanoj Sarcar <kanoj@sgi.com>
  14  * Move the mm functionality over to mm/shmem.c, Christoph Rohland <cr@sap.com>
  15  *
  16  * support for audit of ipc object properties and permission changes
  17  * Dustin Kirkland <dustin.kirkland@us.ibm.com>
  18  *
  19  * namespaces support
  20  * OpenVZ, SWsoft Inc.
  21  * Pavel Emelianov <xemul@openvz.org>
  22  */
  23
  24 #include <linux/slab.h>
  25 #include <linux/mm.h>
  26 #include <linux/hugetlb.h>
  27 #include <linux/shm.h>
  28 #include <linux/init.h>
  29 #include <linux/file.h>
  30 #include <linux/mman.h>
  31 #include <linux/shmem_fs.h>
  32 #include <linux/security.h>
  33 #include <linux/syscalls.h>
  34 #include <linux/audit.h>
  35 #include <linux/capability.h>
  36 #include <linux/ptrace.h>
  37 #include <linux/seq_file.h>
  38 #include <linux/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 if (vma->vm_policy)
 258                 pol = vma->vm_policy;
 259         else
 260                 pol = current->mempolicy;
 261         return pol;
 262 }
 263 #endif
 264
 265 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
 266 {
 267         struct shm_file_data *sfd = shm_file_data(file);
 268         int ret;
 269
 270         ret = sfd->file->f_op->mmap(sfd->file, vma);
 271         if (ret != 0)
 272                 return ret;
 273         sfd->vm_ops = vma->vm_ops;
 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         .nopage = shm_nopage,
 333 #if defined(CONFIG_NUMA)
 334         .set_policy = shm_set_policy,
 335         .get_policy = shm_get_policy,
 336 #endif
 337 };
 338
 339 static int newseg (struct ipc_namespace *ns, key_t key, int shmflg, size_t size)
 340 {
 341         int error;
 342         struct shmid_kernel *shp;
 343         int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
 344         struct file * file;
 345         char name[13];
 346         int id;
 347
 348         if (size < SHMMIN || size > ns->shm_ctlmax)
 349                 return -EINVAL;
 350
 351         if (ns->shm_tot + numpages > ns->shm_ctlall)
 352                 return -ENOSPC;
 353
 354         shp = ipc_rcu_alloc(sizeof(*shp));
 355         if (!shp)
 356                 return -ENOMEM;
 357
 358         shp->shm_perm.key = key;
 359         shp->shm_perm.mode = (shmflg & S_IRWXUGO);
 360         shp->mlock_user = NULL;
 361
 362         shp->shm_perm.security = NULL;
 363         error = security_shm_alloc(shp);
 364         if (error) {
 365                 ipc_rcu_putref(shp);
 366                 return error;
 367         }
 368
 369         sprintf (name, "SYSV%08x", key);
 370         if (shmflg & SHM_HUGETLB) {
 371                 /* hugetlb_file_setup takes care of mlock user accounting */
 372                 file = hugetlb_file_setup(name, size);
 373                 shp->mlock_user = current->user;
 374         } else {
 375                 int acctflag = VM_ACCOUNT;
 376                 /*
 377                  * Do not allow no accounting for OVERCOMMIT_NEVER, even
 378                  * if it's asked for.
 379                  */
 380                 if  ((shmflg & SHM_NORESERVE) &&
 381                                 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
 382                         acctflag = 0;
 383                 file = shmem_file_setup(name, size, acctflag);
 384         }
 385         error = PTR_ERR(file);
 386         if (IS_ERR(file))
 387                 goto no_file;
 388
 389         error = -ENOSPC;
 390         id = shm_addid(ns, shp);
 391         if(id == -1)
 392                 goto no_id;
 393
 394         shp->shm_cprid = current->tgid;
 395         shp->shm_lprid = 0;
 396         shp->shm_atim = shp->shm_dtim = 0;
 397         shp->shm_ctim = get_seconds();
 398         shp->shm_segsz = size;
 399         shp->shm_nattch = 0;
 400         shp->id = shm_buildid(ns, id, shp->shm_perm.seq);
 401         shp->shm_file = file;
 402         /*
 403          * shmid gets reported as "inode#" in /proc/pid/maps.
 404          * proc-ps tools use this. Changing this will break them.
 405          */
 406         file->f_dentry->d_inode->i_ino = shp->id;
 407
 408         ns->shm_tot += numpages;
 409         shm_unlock(shp);
 410         return shp->id;
 411
 412 no_id:
 413         fput(file);
 414 no_file:
 415         security_shm_free(shp);
 416         ipc_rcu_putref(shp);
 417         return error;
 418 }
 419
 420 asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
 421 {
 422         struct shmid_kernel *shp;
 423         int err, id = 0;
 424         struct ipc_namespace *ns;
 425
 426         ns = current->nsproxy->ipc_ns;
 427
 428         mutex_lock(&shm_ids(ns).mutex);
 429         if (key == IPC_PRIVATE) {
 430                 err = newseg(ns, key, shmflg, size);
 431         } else if ((id = ipc_findkey(&shm_ids(ns), key)) == -1) {
 432                 if (!(shmflg & IPC_CREAT))
 433                         err = -ENOENT;
 434                 else
 435                         err = newseg(ns, key, shmflg, size);
 436         } else if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL)) {
 437                 err = -EEXIST;
 438         } else {
 439                 shp = shm_lock(ns, id);
 440                 BUG_ON(shp==NULL);
 441                 if (shp->shm_segsz < size)
 442                         err = -EINVAL;
 443                 else if (ipcperms(&shp->shm_perm, shmflg))
 444                         err = -EACCES;
 445                 else {
 446                         int shmid = shm_buildid(ns, id, shp->shm_perm.seq);
 447                         err = security_shm_associate(shp, shmflg);
 448                         if (!err)
 449                                 err = shmid;
 450                 }
 451                 shm_unlock(shp);
 452         }
 453         mutex_unlock(&shm_ids(ns).mutex);
 454
 455         return err;
 456 }
 457
 458 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
 459 {
 460         switch(version) {
 461         case IPC_64:
 462                 return copy_to_user(buf, in, sizeof(*in));
 463         case IPC_OLD:
 464             {
 465                 struct shmid_ds out;
 466
 467                 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
 468                 out.shm_segsz   = in->shm_segsz;
 469                 out.shm_atime   = in->shm_atime;
 470                 out.shm_dtime   = in->shm_dtime;
 471                 out.shm_ctime   = in->shm_ctime;
 472                 out.shm_cpid    = in->shm_cpid;
 473                 out.shm_lpid    = in->shm_lpid;
 474                 out.shm_nattch  = in->shm_nattch;
 475
 476                 return copy_to_user(buf, &out, sizeof(out));
 477             }
 478         default:
 479                 return -EINVAL;
 480         }
 481 }
 482
 483 struct shm_setbuf {
 484         uid_t   uid;
 485         gid_t   gid;
 486         mode_t  mode;
 487 };
 488
 489 static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
 490 {
 491         switch(version) {
 492         case IPC_64:
 493             {
 494                 struct shmid64_ds tbuf;
 495
 496                 if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
 497                         return -EFAULT;
 498
 499                 out->uid        = tbuf.shm_perm.uid;
 500                 out->gid        = tbuf.shm_perm.gid;
 501                 out->mode       = tbuf.shm_perm.mode;
 502
 503                 return 0;
 504             }
 505         case IPC_OLD:
 506             {
 507                 struct shmid_ds tbuf_old;
 508
 509                 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
 510                         return -EFAULT;
 511
 512                 out->uid        = tbuf_old.shm_perm.uid;
 513                 out->gid        = tbuf_old.shm_perm.gid;
 514                 out->mode       = tbuf_old.shm_perm.mode;
 515
 516                 return 0;
 517             }
 518         default:
 519                 return -EINVAL;
 520         }
 521 }
 522
 523 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
 524 {
 525         switch(version) {
 526         case IPC_64:
 527                 return copy_to_user(buf, in, sizeof(*in));
 528         case IPC_OLD:
 529             {
 530                 struct shminfo out;
 531
 532                 if(in->shmmax > INT_MAX)
 533                         out.shmmax = INT_MAX;
 534                 else
 535                         out.shmmax = (int)in->shmmax;
 536
 537                 out.shmmin      = in->shmmin;
 538                 out.shmmni      = in->shmmni;
 539                 out.shmseg      = in->shmseg;
 540                 out.shmall      = in->shmall;
 541
 542                 return copy_to_user(buf, &out, sizeof(out));
 543             }
 544         default:
 545                 return -EINVAL;
 546         }
 547 }
 548
 549 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
 550                 unsigned long *swp)
 551 {
 552         int i;
 553
 554         *rss = 0;
 555         *swp = 0;
 556
 557         for (i = 0; i <= shm_ids(ns).max_id; i++) {
 558                 struct shmid_kernel *shp;
 559                 struct inode *inode;
 560
 561                 shp = shm_get(ns, i);
 562                 if(!shp)
 563                         continue;
 564
 565                 inode = shp->shm_file->f_path.dentry->d_inode;
 566
 567                 if (is_file_hugepages(shp->shm_file)) {
 568                         struct address_space *mapping = inode->i_mapping;
 569                         *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
 570                 } else {
 571                         struct shmem_inode_info *info = SHMEM_I(inode);
 572                         spin_lock(&info->lock);
 573                         *rss += inode->i_mapping->nrpages;
 574                         *swp += info->swapped;
 575                         spin_unlock(&info->lock);
 576                 }
 577         }
 578 }
 579
 580 asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
 581 {
 582         struct shm_setbuf setbuf;
 583         struct shmid_kernel *shp;
 584         int err, version;
 585         struct ipc_namespace *ns;
 586
 587         if (cmd < 0 || shmid < 0) {
 588                 err = -EINVAL;
 589                 goto out;
 590         }
 591
 592         version = ipc_parse_version(&cmd);
 593         ns = current->nsproxy->ipc_ns;
 594
 595         switch (cmd) { /* replace with proc interface ? */
 596         case IPC_INFO:
 597         {
 598                 struct shminfo64 shminfo;
 599
 600                 err = security_shm_shmctl(NULL, cmd);
 601                 if (err)
 602                         return err;
 603
 604                 memset(&shminfo,0,sizeof(shminfo));
 605                 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
 606                 shminfo.shmmax = ns->shm_ctlmax;
 607                 shminfo.shmall = ns->shm_ctlall;
 608
 609                 shminfo.shmmin = SHMMIN;
 610                 if(copy_shminfo_to_user (buf, &shminfo, version))
 611                         return -EFAULT;
 612                 /* reading a integer is always atomic */
 613                 err= shm_ids(ns).max_id;
 614                 if(err<0)
 615                         err = 0;
 616                 goto out;
 617         }
 618         case SHM_INFO:
 619         {
 620                 struct shm_info shm_info;
 621
 622                 err = security_shm_shmctl(NULL, cmd);
 623                 if (err)
 624                         return err;
 625
 626                 memset(&shm_info,0,sizeof(shm_info));
 627                 mutex_lock(&shm_ids(ns).mutex);
 628                 shm_info.used_ids = shm_ids(ns).in_use;
 629                 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
 630                 shm_info.shm_tot = ns->shm_tot;
 631                 shm_info.swap_attempts = 0;
 632                 shm_info.swap_successes = 0;
 633                 err = shm_ids(ns).max_id;
 634                 mutex_unlock(&shm_ids(ns).mutex);
 635                 if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
 636                         err = -EFAULT;
 637                         goto out;
 638                 }
 639
 640                 err = err < 0 ? 0 : err;
 641                 goto out;
 642         }
 643         case SHM_STAT:
 644         case IPC_STAT:
 645         {
 646                 struct shmid64_ds tbuf;
 647                 int result;
 648                 memset(&tbuf, 0, sizeof(tbuf));
 649                 shp = shm_lock(ns, shmid);
 650                 if(shp==NULL) {
 651                         err = -EINVAL;
 652                         goto out;
 653                 } else if(cmd==SHM_STAT) {
 654                         err = -EINVAL;
 655                         if (shmid > shm_ids(ns).max_id)
 656                                 goto out_unlock;
 657                         result = shm_buildid(ns, shmid, shp->shm_perm.seq);
 658                 } else {
 659                         err = shm_checkid(ns, shp,shmid);
 660                         if(err)
 661                                 goto out_unlock;
 662                         result = 0;
 663                 }
 664                 err=-EACCES;
 665                 if (ipcperms (&shp->shm_perm, S_IRUGO))
 666                         goto out_unlock;
 667                 err = security_shm_shmctl(shp, cmd);
 668                 if (err)
 669                         goto out_unlock;
 670                 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
 671                 tbuf.shm_segsz  = shp->shm_segsz;
 672                 tbuf.shm_atime  = shp->shm_atim;
 673                 tbuf.shm_dtime  = shp->shm_dtim;
 674                 tbuf.shm_ctime  = shp->shm_ctim;
 675                 tbuf.shm_cpid   = shp->shm_cprid;
 676                 tbuf.shm_lpid   = shp->shm_lprid;
 677                 tbuf.shm_nattch = shp->shm_nattch;
 678                 shm_unlock(shp);
 679                 if(copy_shmid_to_user (buf, &tbuf, version))
 680                         err = -EFAULT;
 681                 else
 682                         err = result;
 683                 goto out;
 684         }
 685         case SHM_LOCK:
 686         case SHM_UNLOCK:
 687         {
 688                 shp = shm_lock(ns, shmid);
 689                 if(shp==NULL) {
 690                         err = -EINVAL;
 691                         goto out;
 692                 }
 693                 err = shm_checkid(ns, shp,shmid);
 694                 if(err)
 695                         goto out_unlock;
 696
 697                 err = audit_ipc_obj(&(shp->shm_perm));
 698                 if (err)
 699                         goto out_unlock;
 700
 701                 if (!capable(CAP_IPC_LOCK)) {
 702                         err = -EPERM;
 703                         if (current->euid != shp->shm_perm.uid &&
 704                             current->euid != shp->shm_perm.cuid)
 705                                 goto out_unlock;
 706                         if (cmd == SHM_LOCK &&
 707                             !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
 708                                 goto out_unlock;
 709                 }
 710
 711                 err = security_shm_shmctl(shp, cmd);
 712                 if (err)
 713                         goto out_unlock;
 714
 715                 if(cmd==SHM_LOCK) {
 716                         struct user_struct * user = current->user;
 717                         if (!is_file_hugepages(shp->shm_file)) {
 718                                 err = shmem_lock(shp->shm_file, 1, user);
 719                                 if (!err) {
 720                                         shp->shm_perm.mode |= SHM_LOCKED;
 721                                         shp->mlock_user = user;
 722                                 }
 723                         }
 724                 } else if (!is_file_hugepages(shp->shm_file)) {
 725                         shmem_lock(shp->shm_file, 0, shp->mlock_user);
 726                         shp->shm_perm.mode &= ~SHM_LOCKED;
 727                         shp->mlock_user = NULL;
 728                 }
 729                 shm_unlock(shp);
 730                 goto out;
 731         }
 732         case IPC_RMID:
 733         {
 734                 /*
 735                  *      We cannot simply remove the file. The SVID states
 736                  *      that the block remains until the last person
 737                  *      detaches from it, then is deleted. A shmat() on
 738                  *      an RMID segment is legal in older Linux and if
 739                  *      we change it apps break...
 740                  *
 741                  *      Instead we set a destroyed flag, and then blow
 742                  *      the name away when the usage hits zero.
 743                  */
 744                 mutex_lock(&shm_ids(ns).mutex);
 745                 shp = shm_lock(ns, shmid);
 746                 err = -EINVAL;
 747                 if (shp == NULL)
 748                         goto out_up;
 749                 err = shm_checkid(ns, shp, shmid);
 750                 if(err)
 751                         goto out_unlock_up;
 752
 753                 err = audit_ipc_obj(&(shp->shm_perm));
 754                 if (err)
 755                         goto out_unlock_up;
 756
 757                 if (current->euid != shp->shm_perm.uid &&
 758                     current->euid != shp->shm_perm.cuid &&
 759                     !capable(CAP_SYS_ADMIN)) {
 760                         err=-EPERM;
 761                         goto out_unlock_up;
 762                 }
 763
 764                 err = security_shm_shmctl(shp, cmd);
 765                 if (err)
 766                         goto out_unlock_up;
 767
 768                 do_shm_rmid(ns, shp);
 769                 mutex_unlock(&shm_ids(ns).mutex);
 770                 goto out;
 771         }
 772
 773         case IPC_SET:
 774         {
 775                 if (copy_shmid_from_user (&setbuf, buf, version)) {
 776                         err = -EFAULT;
 777                         goto out;
 778                 }
 779                 mutex_lock(&shm_ids(ns).mutex);
 780                 shp = shm_lock(ns, shmid);
 781                 err=-EINVAL;
 782                 if(shp==NULL)
 783                         goto out_up;
 784                 err = shm_checkid(ns, shp,shmid);
 785                 if(err)
 786                         goto out_unlock_up;
 787                 err = audit_ipc_obj(&(shp->shm_perm));
 788                 if (err)
 789                         goto out_unlock_up;
 790                 err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode);
 791                 if (err)
 792                         goto out_unlock_up;
 793                 err=-EPERM;
 794                 if (current->euid != shp->shm_perm.uid &&
 795                     current->euid != shp->shm_perm.cuid &&
 796                     !capable(CAP_SYS_ADMIN)) {
 797                         goto out_unlock_up;
 798                 }
 799
 800                 err = security_shm_shmctl(shp, cmd);
 801                 if (err)
 802                         goto out_unlock_up;
 803
 804                 shp->shm_perm.uid = setbuf.uid;
 805                 shp->shm_perm.gid = setbuf.gid;
 806                 shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO)
 807                         | (setbuf.mode & S_IRWXUGO);
 808                 shp->shm_ctim = get_seconds();
 809                 break;
 810         }
 811
 812         default:
 813                 err = -EINVAL;
 814                 goto out;
 815         }
 816
 817         err = 0;
 818 out_unlock_up:
 819         shm_unlock(shp);
 820 out_up:
 821         mutex_unlock(&shm_ids(ns).mutex);
 822         goto out;
 823 out_unlock:
 824         shm_unlock(shp);
 825 out:
 826         return err;
 827 }
 828
 829 /*
 830  * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
 831  *
 832  * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
 833  * "raddr" thing points to kernel space, and there has to be a wrapper around
 834  * this.
 835  */
 836 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
 837 {
 838         struct shmid_kernel *shp;
 839         unsigned long addr;
 840         unsigned long size;
 841         struct file * file;
 842         int    err;
 843         unsigned long flags;
 844         unsigned long prot;
 845         int acc_mode;
 846         unsigned long user_addr;
 847         struct ipc_namespace *ns;
 848         struct shm_file_data *sfd;
 849         struct path path;
 850         mode_t f_mode;
 851
 852         err = -EINVAL;
 853         if (shmid < 0)
 854                 goto out;
 855         else if ((addr = (ulong)shmaddr)) {
 856                 if (addr & (SHMLBA-1)) {
 857                         if (shmflg & SHM_RND)
 858                                 addr &= ~(SHMLBA-1);       /* round down */
 859                         else
 860 #ifndef __ARCH_FORCE_SHMLBA
 861                                 if (addr & ~PAGE_MASK)
 862 #endif
 863                                         goto out;
 864                 }
 865                 flags = MAP_SHARED | MAP_FIXED;
 866         } else {
 867                 if ((shmflg & SHM_REMAP))
 868                         goto out;
 869
 870                 flags = MAP_SHARED;
 871         }
 872
 873         if (shmflg & SHM_RDONLY) {
 874                 prot = PROT_READ;
 875                 acc_mode = S_IRUGO;
 876                 f_mode = FMODE_READ;
 877         } else {
 878                 prot = PROT_READ | PROT_WRITE;
 879                 acc_mode = S_IRUGO | S_IWUGO;
 880                 f_mode = FMODE_READ | FMODE_WRITE;
 881         }
 882         if (shmflg & SHM_EXEC) {
 883                 prot |= PROT_EXEC;
 884                 acc_mode |= S_IXUGO;
 885         }
 886
 887         /*
 888          * We cannot rely on the fs check since SYSV IPC does have an
 889          * additional creator id...
 890          */
 891         ns = current->nsproxy->ipc_ns;
 892         shp = shm_lock(ns, shmid);
 893         if(shp == NULL)
 894                 goto out;
 895
 896         err = shm_checkid(ns, shp,shmid);
 897         if (err)
 898                 goto out_unlock;
 899
 900         err = -EACCES;
 901         if (ipcperms(&shp->shm_perm, acc_mode))
 902                 goto out_unlock;
 903
 904         err = security_shm_shmat(shp, shmaddr, shmflg);
 905         if (err)
 906                 goto out_unlock;
 907
 908         path.dentry = dget(shp->shm_file->f_path.dentry);
 909         path.mnt    = mntget(shp->shm_file->f_path.mnt);
 910         shp->shm_nattch++;
 911         size = i_size_read(path.dentry->d_inode);
 912         shm_unlock(shp);
 913
 914         err = -ENOMEM;
 915         sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
 916         if (!sfd)
 917                 goto out_put_path;
 918
 919         err = -ENOMEM;
 920         file = get_empty_filp();
 921         if (!file)
 922                 goto out_free;
 923
 924         file->f_op = &shm_file_operations;
 925         file->private_data = sfd;
 926         file->f_path = path;
 927         file->f_mapping = shp->shm_file->f_mapping;
 928         file->f_mode = f_mode;
 929         sfd->id = shp->id;
 930         sfd->ns = get_ipc_ns(ns);
 931         sfd->file = shp->shm_file;
 932         sfd->vm_ops = NULL;
 933
 934         down_write(&current->mm->mmap_sem);
 935         if (addr && !(shmflg & SHM_REMAP)) {
 936                 err = -EINVAL;
 937                 if (find_vma_intersection(current->mm, addr, addr + size))
 938                         goto invalid;
 939                 /*
 940                  * If shm segment goes below stack, make sure there is some
 941                  * space left for the stack to grow (at least 4 pages).
 942                  */
 943                 if (addr < current->mm->start_stack &&
 944                     addr > current->mm->start_stack - size - PAGE_SIZE * 5)
 945                         goto invalid;
 946         }
 947
 948         user_addr = do_mmap (file, addr, size, prot, flags, 0);
 949         *raddr = user_addr;
 950         err = 0;
 951         if (IS_ERR_VALUE(user_addr))
 952                 err = (long)user_addr;
 953 invalid:
 954         up_write(&current->mm->mmap_sem);
 955
 956         fput(file);
 957
 958 out_nattch:
 959         mutex_lock(&shm_ids(ns).mutex);
 960         shp = shm_lock(ns, shmid);
 961         BUG_ON(!shp);
 962         shp->shm_nattch--;
 963         if(shp->shm_nattch == 0 &&
 964            shp->shm_perm.mode & SHM_DEST)
 965                 shm_destroy(ns, shp);
 966         else
 967                 shm_unlock(shp);
 968         mutex_unlock(&shm_ids(ns).mutex);
 969
 970 out:
 971         return err;
 972
 973 out_unlock:
 974         shm_unlock(shp);
 975         goto out;
 976
 977 out_free:
 978         kfree(sfd);
 979 out_put_path:
 980         dput(path.dentry);
 981         mntput(path.mnt);
 982         goto out_nattch;
 983 }
 984
 985 asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
 986 {
 987         unsigned long ret;
 988         long err;
 989
 990         err = do_shmat(shmid, shmaddr, shmflg, &ret);
 991         if (err)
 992                 return err;
 993         force_successful_syscall_return();
 994         return (long)ret;
 995 }
 996
 997 /*
 998  * detach and kill segment if marked destroyed.
 999  * The work is done in shm_close.
1000  */
1001 asmlinkage long sys_shmdt(char __user *shmaddr)
1002 {
1003         struct mm_struct *mm = current->mm;
1004         struct vm_area_struct *vma, *next;
1005         unsigned long addr = (unsigned long)shmaddr;
1006         loff_t size = 0;
1007         int retval = -EINVAL;
1008
1009         if (addr & ~PAGE_MASK)
1010                 return retval;
1011
1012         down_write(&mm->mmap_sem);
1013
1014         /*
1015          * This function tries to be smart and unmap shm segments that
1016          * were modified by partial mlock or munmap calls:
1017          * - It first determines the size of the shm segment that should be
1018          *   unmapped: It searches for a vma that is backed by shm and that
1019          *   started at address shmaddr. It records it's size and then unmaps
1020          *   it.
1021          * - Then it unmaps all shm vmas that started at shmaddr and that
1022          *   are within the initially determined size.
1023          * Errors from do_munmap are ignored: the function only fails if
1024          * it's called with invalid parameters or if it's called to unmap
1025          * a part of a vma. Both calls in this function are for full vmas,
1026          * the parameters are directly copied from the vma itself and always
1027          * valid - therefore do_munmap cannot fail. (famous last words?)
1028          */
1029         /*
1030          * If it had been mremap()'d, the starting address would not
1031          * match the usual checks anyway. So assume all vma's are
1032          * above the starting address given.
1033          */
1034         vma = find_vma(mm, addr);
1035
1036         while (vma) {
1037                 next = vma->vm_next;
1038
1039                 /*
1040                  * Check if the starting address would match, i.e. it's
1041                  * a fragment created by mprotect() and/or munmap(), or it
1042                  * otherwise it starts at this address with no hassles.
1043                  */
1044                 if ((vma->vm_ops == &shm_vm_ops) &&
1045                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1046
1047
1048                         size = vma->vm_file->f_path.dentry->d_inode->i_size;
1049                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1050                         /*
1051                          * We discovered the size of the shm segment, so
1052                          * break out of here and fall through to the next
1053                          * loop that uses the size information to stop
1054                          * searching for matching vma's.
1055                          */
1056                         retval = 0;
1057                         vma = next;
1058                         break;
1059                 }
1060                 vma = next;
1061         }
1062
1063         /*
1064          * We need look no further than the maximum address a fragment
1065          * could possibly have landed at. Also cast things to loff_t to
1066          * prevent overflows and make comparisions vs. equal-width types.
1067          */
1068         size = PAGE_ALIGN(size);
1069         while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1070                 next = vma->vm_next;
1071
1072                 /* finding a matching vma now does not alter retval */
1073                 if ((vma->vm_ops == &shm_vm_ops) &&
1074                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1075
1076                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1077                 vma = next;
1078         }
1079
1080         up_write(&mm->mmap_sem);
1081         return retval;
1082 }
1083
1084 #ifdef CONFIG_PROC_FS
1085 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1086 {
1087         struct shmid_kernel *shp = it;
1088         char *format;
1089
1090 #define SMALL_STRING "%10d %10d  %4o %10u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1091 #define BIG_STRING   "%10d %10d  %4o %21u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1092
1093         if (sizeof(size_t) <= sizeof(int))
1094                 format = SMALL_STRING;
1095         else
1096                 format = BIG_STRING;
1097         return seq_printf(s, format,
1098                           shp->shm_perm.key,
1099                           shp->id,
1100                           shp->shm_perm.mode,
1101                           shp->shm_segsz,
1102                           shp->shm_cprid,
1103                           shp->shm_lprid,
1104                           shp->shm_nattch,
1105                           shp->shm_perm.uid,
1106                           shp->shm_perm.gid,
1107                           shp->shm_perm.cuid,
1108                           shp->shm_perm.cgid,
1109                           shp->shm_atim,
1110                           shp->shm_dtim,
1111                           shp->shm_ctim);
1112 }
1113 #endif