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 __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 int shm_init_ns(struct ipc_namespace *ns)
 102 {
 103         struct ipc_ids *ids;
 104
 105         ids = kmalloc(sizeof(struct ipc_ids), GFP_KERNEL);
 106         if (ids == NULL)
 107                 return -ENOMEM;
 108
 109         __shm_init_ns(ns, ids);
 110         return 0;
 111 }
 112
 113 void shm_exit_ns(struct ipc_namespace *ns)
 114 {
 115         int i;
 116         struct shmid_kernel *shp;
 117
 118         mutex_lock(&shm_ids(ns).mutex);
 119         for (i = 0; i <= shm_ids(ns).max_id; i++) {
 120                 shp = shm_lock(ns, i);
 121                 if (shp == NULL)
 122                         continue;
 123
 124                 do_shm_rmid(ns, shp);
 125         }
 126         mutex_unlock(&shm_ids(ns).mutex);
 127
 128         ipc_fini_ids(ns->ids[IPC_SHM_IDS]);
 129         kfree(ns->ids[IPC_SHM_IDS]);
 130         ns->ids[IPC_SHM_IDS] = NULL;
 131 }
 132
 133 void __init shm_init (void)
 134 {
 135         __shm_init_ns(&init_ipc_ns, &init_shm_ids);
 136         ipc_init_proc_interface("sysvipc/shm",
 137                                 "       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime\n",
 138                                 IPC_SHM_IDS, sysvipc_shm_proc_show);
 139 }
 140
 141 static inline int shm_checkid(struct ipc_namespace *ns,
 142                 struct shmid_kernel *s, int id)
 143 {
 144         if (ipc_checkid(&shm_ids(ns), &s->shm_perm, id))
 145                 return -EIDRM;
 146         return 0;
 147 }
 148
 149 static inline struct shmid_kernel *shm_rmid(struct ipc_namespace *ns, int id)
 150 {
 151         return (struct shmid_kernel *)ipc_rmid(&shm_ids(ns), id);
 152 }
 153
 154 static inline int shm_addid(struct ipc_namespace *ns, struct shmid_kernel *shp)
 155 {
 156         return ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
 157 }
 158
 159
 160
 161 /* This is called by fork, once for every shm attach. */
 162 static void shm_open(struct vm_area_struct *vma)
 163 {
 164         struct file *file = vma->vm_file;
 165         struct shm_file_data *sfd = shm_file_data(file);
 166         struct shmid_kernel *shp;
 167
 168         shp = shm_lock(sfd->ns, sfd->id);
 169         BUG_ON(!shp);
 170         shp->shm_atim = get_seconds();
 171         shp->shm_lprid = current->tgid;
 172         shp->shm_nattch++;
 173         shm_unlock(shp);
 174 }
 175
 176 /*
 177  * shm_destroy - free the struct shmid_kernel
 178  *
 179  * @shp: struct to free
 180  *
 181  * It has to be called with shp and shm_ids.mutex 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->id);
 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         mutex_lock(&shm_ids(ns).mutex);
 213         /* remove from the list of attaches of the shm segment */
 214         shp = shm_lock(ns, sfd->id);
 215         BUG_ON(!shp);
 216         shp->shm_lprid = current->tgid;
 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         mutex_unlock(&shm_ids(ns).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 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 struct mempolicy *shm_get_policy(struct vm_area_struct *vma, unsigned long addr)
 247 {
 248         struct file *file = vma->vm_file;
 249         struct shm_file_data *sfd = shm_file_data(file);
 250         struct mempolicy *pol = NULL;
 251
 252         if (sfd->vm_ops->get_policy)
 253                 pol = sfd->vm_ops->get_policy(vma, addr);
 254         else if (vma->vm_policy)
 255                 pol = vma->vm_policy;
 256         else
 257                 pol = current->mempolicy;
 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         BUG_ON(!sfd->vm_ops->fault);
 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         .fault  = shm_fault,
 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         sprintf (name, "SYSV%08x", key);
 368         if (shmflg & SHM_HUGETLB) {
 369                 /* hugetlb_file_setup takes care of mlock user accounting */
 370                 file = hugetlb_file_setup(name, size);
 371                 shp->mlock_user = current->user;
 372         } else {
 373                 int acctflag = VM_ACCOUNT;
 374                 /*
 375                  * Do not allow no accounting for OVERCOMMIT_NEVER, even
 376                  * if it's asked for.
 377                  */
 378                 if  ((shmflg & SHM_NORESERVE) &&
 379                                 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
 380                         acctflag = 0;
 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          * shmid gets reported as "inode#" in /proc/pid/maps.
 402          * proc-ps tools use this. Changing this will break them.
 403          */
 404         file->f_dentry->d_inode->i_ino = shp->id;
 405
 406         ns->shm_tot += numpages;
 407         shm_unlock(shp);
 408         return shp->id;
 409
 410 no_id:
 411         fput(file);
 412 no_file:
 413         security_shm_free(shp);
 414         ipc_rcu_putref(shp);
 415         return error;
 416 }
 417
 418 asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
 419 {
 420         struct shmid_kernel *shp;
 421         int err, id = 0;
 422         struct ipc_namespace *ns;
 423
 424         ns = current->nsproxy->ipc_ns;
 425
 426         mutex_lock(&shm_ids(ns).mutex);
 427         if (key == IPC_PRIVATE) {
 428                 err = newseg(ns, key, shmflg, size);
 429         } else if ((id = ipc_findkey(&shm_ids(ns), key)) == -1) {
 430                 if (!(shmflg & IPC_CREAT))
 431                         err = -ENOENT;
 432                 else
 433                         err = newseg(ns, key, shmflg, size);
 434         } else if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL)) {
 435                 err = -EEXIST;
 436         } else {
 437                 shp = shm_lock(ns, id);
 438                 BUG_ON(shp==NULL);
 439                 if (shp->shm_segsz < size)
 440                         err = -EINVAL;
 441                 else if (ipcperms(&shp->shm_perm, shmflg))
 442                         err = -EACCES;
 443                 else {
 444                         int shmid = shm_buildid(ns, id, shp->shm_perm.seq);
 445                         err = security_shm_associate(shp, shmflg);
 446                         if (!err)
 447                                 err = shmid;
 448                 }
 449                 shm_unlock(shp);
 450         }
 451         mutex_unlock(&shm_ids(ns).mutex);
 452
 453         return err;
 454 }
 455
 456 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
 457 {
 458         switch(version) {
 459         case IPC_64:
 460                 return copy_to_user(buf, in, sizeof(*in));
 461         case IPC_OLD:
 462             {
 463                 struct shmid_ds out;
 464
 465                 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
 466                 out.shm_segsz   = in->shm_segsz;
 467                 out.shm_atime   = in->shm_atime;
 468                 out.shm_dtime   = in->shm_dtime;
 469                 out.shm_ctime   = in->shm_ctime;
 470                 out.shm_cpid    = in->shm_cpid;
 471                 out.shm_lpid    = in->shm_lpid;
 472                 out.shm_nattch  = in->shm_nattch;
 473
 474                 return copy_to_user(buf, &out, sizeof(out));
 475             }
 476         default:
 477                 return -EINVAL;
 478         }
 479 }
 480
 481 struct shm_setbuf {
 482         uid_t   uid;
 483         gid_t   gid;
 484         mode_t  mode;
 485 };
 486
 487 static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
 488 {
 489         switch(version) {
 490         case IPC_64:
 491             {
 492                 struct shmid64_ds tbuf;
 493
 494                 if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
 495                         return -EFAULT;
 496
 497                 out->uid        = tbuf.shm_perm.uid;
 498                 out->gid        = tbuf.shm_perm.gid;
 499                 out->mode       = tbuf.shm_perm.mode;
 500
 501                 return 0;
 502             }
 503         case IPC_OLD:
 504             {
 505                 struct shmid_ds tbuf_old;
 506
 507                 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
 508                         return -EFAULT;
 509
 510                 out->uid        = tbuf_old.shm_perm.uid;
 511                 out->gid        = tbuf_old.shm_perm.gid;
 512                 out->mode       = tbuf_old.shm_perm.mode;
 513
 514                 return 0;
 515             }
 516         default:
 517                 return -EINVAL;
 518         }
 519 }
 520
 521 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
 522 {
 523         switch(version) {
 524         case IPC_64:
 525                 return copy_to_user(buf, in, sizeof(*in));
 526         case IPC_OLD:
 527             {
 528                 struct shminfo out;
 529
 530                 if(in->shmmax > INT_MAX)
 531                         out.shmmax = INT_MAX;
 532                 else
 533                         out.shmmax = (int)in->shmmax;
 534
 535                 out.shmmin      = in->shmmin;
 536                 out.shmmni      = in->shmmni;
 537                 out.shmseg      = in->shmseg;
 538                 out.shmall      = in->shmall;
 539
 540                 return copy_to_user(buf, &out, sizeof(out));
 541             }
 542         default:
 543                 return -EINVAL;
 544         }
 545 }
 546
 547 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
 548                 unsigned long *swp)
 549 {
 550         int i;
 551
 552         *rss = 0;
 553         *swp = 0;
 554
 555         for (i = 0; i <= shm_ids(ns).max_id; i++) {
 556                 struct shmid_kernel *shp;
 557                 struct inode *inode;
 558
 559                 shp = shm_get(ns, i);
 560                 if(!shp)
 561                         continue;
 562
 563                 inode = shp->shm_file->f_path.dentry->d_inode;
 564
 565                 if (is_file_hugepages(shp->shm_file)) {
 566                         struct address_space *mapping = inode->i_mapping;
 567                         *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
 568                 } else {
 569                         struct shmem_inode_info *info = SHMEM_I(inode);
 570                         spin_lock(&info->lock);
 571                         *rss += inode->i_mapping->nrpages;
 572                         *swp += info->swapped;
 573                         spin_unlock(&info->lock);
 574                 }
 575         }
 576 }
 577
 578 asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
 579 {
 580         struct shm_setbuf setbuf;
 581         struct shmid_kernel *shp;
 582         int err, version;
 583         struct ipc_namespace *ns;
 584
 585         if (cmd < 0 || shmid < 0) {
 586                 err = -EINVAL;
 587                 goto out;
 588         }
 589
 590         version = ipc_parse_version(&cmd);
 591         ns = current->nsproxy->ipc_ns;
 592
 593         switch (cmd) { /* replace with proc interface ? */
 594         case IPC_INFO:
 595         {
 596                 struct shminfo64 shminfo;
 597
 598                 err = security_shm_shmctl(NULL, cmd);
 599                 if (err)
 600                         return err;
 601
 602                 memset(&shminfo,0,sizeof(shminfo));
 603                 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
 604                 shminfo.shmmax = ns->shm_ctlmax;
 605                 shminfo.shmall = ns->shm_ctlall;
 606
 607                 shminfo.shmmin = SHMMIN;
 608                 if(copy_shminfo_to_user (buf, &shminfo, version))
 609                         return -EFAULT;
 610                 /* reading a integer is always atomic */
 611                 err= shm_ids(ns).max_id;
 612                 if(err<0)
 613                         err = 0;
 614                 goto out;
 615         }
 616         case SHM_INFO:
 617         {
 618                 struct shm_info shm_info;
 619
 620                 err = security_shm_shmctl(NULL, cmd);
 621                 if (err)
 622                         return err;
 623
 624                 memset(&shm_info,0,sizeof(shm_info));
 625                 mutex_lock(&shm_ids(ns).mutex);
 626                 shm_info.used_ids = shm_ids(ns).in_use;
 627                 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
 628                 shm_info.shm_tot = ns->shm_tot;
 629                 shm_info.swap_attempts = 0;
 630                 shm_info.swap_successes = 0;
 631                 err = shm_ids(ns).max_id;
 632                 mutex_unlock(&shm_ids(ns).mutex);
 633                 if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
 634                         err = -EFAULT;
 635                         goto out;
 636                 }
 637
 638                 err = err < 0 ? 0 : err;
 639                 goto out;
 640         }
 641         case SHM_STAT:
 642         case IPC_STAT:
 643         {
 644                 struct shmid64_ds tbuf;
 645                 int result;
 646                 memset(&tbuf, 0, sizeof(tbuf));
 647                 shp = shm_lock(ns, shmid);
 648                 if(shp==NULL) {
 649                         err = -EINVAL;
 650                         goto out;
 651                 } else if(cmd==SHM_STAT) {
 652                         err = -EINVAL;
 653                         if (shmid > shm_ids(ns).max_id)
 654                                 goto out_unlock;
 655                         result = shm_buildid(ns, shmid, shp->shm_perm.seq);
 656                 } else {
 657                         err = shm_checkid(ns, shp,shmid);
 658                         if(err)
 659                                 goto out_unlock;
 660                         result = 0;
 661                 }
 662                 err=-EACCES;
 663                 if (ipcperms (&shp->shm_perm, S_IRUGO))
 664                         goto out_unlock;
 665                 err = security_shm_shmctl(shp, cmd);
 666                 if (err)
 667                         goto out_unlock;
 668                 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
 669                 tbuf.shm_segsz  = shp->shm_segsz;
 670                 tbuf.shm_atime  = shp->shm_atim;
 671                 tbuf.shm_dtime  = shp->shm_dtim;
 672                 tbuf.shm_ctime  = shp->shm_ctim;
 673                 tbuf.shm_cpid   = shp->shm_cprid;
 674                 tbuf.shm_lpid   = shp->shm_lprid;
 675                 tbuf.shm_nattch = shp->shm_nattch;
 676                 shm_unlock(shp);
 677                 if(copy_shmid_to_user (buf, &tbuf, version))
 678                         err = -EFAULT;
 679                 else
 680                         err = result;
 681                 goto out;
 682         }
 683         case SHM_LOCK:
 684         case SHM_UNLOCK:
 685         {
 686                 shp = shm_lock(ns, shmid);
 687                 if(shp==NULL) {
 688                         err = -EINVAL;
 689                         goto out;
 690                 }
 691                 err = shm_checkid(ns, shp,shmid);
 692                 if(err)
 693                         goto out_unlock;
 694
 695                 err = audit_ipc_obj(&(shp->shm_perm));
 696                 if (err)
 697                         goto out_unlock;
 698
 699                 if (!capable(CAP_IPC_LOCK)) {
 700                         err = -EPERM;
 701                         if (current->euid != shp->shm_perm.uid &&
 702                             current->euid != shp->shm_perm.cuid)
 703                                 goto out_unlock;
 704                         if (cmd == SHM_LOCK &&
 705                             !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
 706                                 goto out_unlock;
 707                 }
 708
 709                 err = security_shm_shmctl(shp, cmd);
 710                 if (err)
 711                         goto out_unlock;
 712
 713                 if(cmd==SHM_LOCK) {
 714                         struct user_struct * user = current->user;
 715                         if (!is_file_hugepages(shp->shm_file)) {
 716                                 err = shmem_lock(shp->shm_file, 1, user);
 717                                 if (!err) {
 718                                         shp->shm_perm.mode |= SHM_LOCKED;
 719                                         shp->mlock_user = user;
 720                                 }
 721                         }
 722                 } else if (!is_file_hugepages(shp->shm_file)) {
 723                         shmem_lock(shp->shm_file, 0, shp->mlock_user);
 724                         shp->shm_perm.mode &= ~SHM_LOCKED;
 725                         shp->mlock_user = NULL;
 726                 }
 727                 shm_unlock(shp);
 728                 goto out;
 729         }
 730         case IPC_RMID:
 731         {
 732                 /*
 733                  *      We cannot simply remove the file. The SVID states
 734                  *      that the block remains until the last person
 735                  *      detaches from it, then is deleted. A shmat() on
 736                  *      an RMID segment is legal in older Linux and if
 737                  *      we change it apps break...
 738                  *
 739                  *      Instead we set a destroyed flag, and then blow
 740                  *      the name away when the usage hits zero.
 741                  */
 742                 mutex_lock(&shm_ids(ns).mutex);
 743                 shp = shm_lock(ns, shmid);
 744                 err = -EINVAL;
 745                 if (shp == NULL)
 746                         goto out_up;
 747                 err = shm_checkid(ns, shp, shmid);
 748                 if(err)
 749                         goto out_unlock_up;
 750
 751                 err = audit_ipc_obj(&(shp->shm_perm));
 752                 if (err)
 753                         goto out_unlock_up;
 754
 755                 if (current->euid != shp->shm_perm.uid &&
 756                     current->euid != shp->shm_perm.cuid &&
 757                     !capable(CAP_SYS_ADMIN)) {
 758                         err=-EPERM;
 759                         goto out_unlock_up;
 760                 }
 761
 762                 err = security_shm_shmctl(shp, cmd);
 763                 if (err)
 764                         goto out_unlock_up;
 765
 766                 do_shm_rmid(ns, shp);
 767                 mutex_unlock(&shm_ids(ns).mutex);
 768                 goto out;
 769         }
 770
 771         case IPC_SET:
 772         {
 773                 if (copy_shmid_from_user (&setbuf, buf, version)) {
 774                         err = -EFAULT;
 775                         goto out;
 776                 }
 777                 mutex_lock(&shm_ids(ns).mutex);
 778                 shp = shm_lock(ns, shmid);
 779                 err=-EINVAL;
 780                 if(shp==NULL)
 781                         goto out_up;
 782                 err = shm_checkid(ns, shp,shmid);
 783                 if(err)
 784                         goto out_unlock_up;
 785                 err = audit_ipc_obj(&(shp->shm_perm));
 786                 if (err)
 787                         goto out_unlock_up;
 788                 err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode);
 789                 if (err)
 790                         goto out_unlock_up;
 791                 err=-EPERM;
 792                 if (current->euid != shp->shm_perm.uid &&
 793                     current->euid != shp->shm_perm.cuid &&
 794                     !capable(CAP_SYS_ADMIN)) {
 795                         goto out_unlock_up;
 796                 }
 797
 798                 err = security_shm_shmctl(shp, cmd);
 799                 if (err)
 800                         goto out_unlock_up;
 801
 802                 shp->shm_perm.uid = setbuf.uid;
 803                 shp->shm_perm.gid = setbuf.gid;
 804                 shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO)
 805                         | (setbuf.mode & S_IRWXUGO);
 806                 shp->shm_ctim = get_seconds();
 807                 break;
 808         }
 809
 810         default:
 811                 err = -EINVAL;
 812                 goto out;
 813         }
 814
 815         err = 0;
 816 out_unlock_up:
 817         shm_unlock(shp);
 818 out_up:
 819         mutex_unlock(&shm_ids(ns).mutex);
 820         goto out;
 821 out_unlock:
 822         shm_unlock(shp);
 823 out:
 824         return err;
 825 }
 826
 827 /*
 828  * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
 829  *
 830  * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
 831  * "raddr" thing points to kernel space, and there has to be a wrapper around
 832  * this.
 833  */
 834 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
 835 {
 836         struct shmid_kernel *shp;
 837         unsigned long addr;
 838         unsigned long size;
 839         struct file * file;
 840         int    err;
 841         unsigned long flags;
 842         unsigned long prot;
 843         int acc_mode;
 844         unsigned long user_addr;
 845         struct ipc_namespace *ns;
 846         struct shm_file_data *sfd;
 847         struct path path;
 848         mode_t f_mode;
 849
 850         err = -EINVAL;
 851         if (shmid < 0)
 852                 goto out;
 853         else if ((addr = (ulong)shmaddr)) {
 854                 if (addr & (SHMLBA-1)) {
 855                         if (shmflg & SHM_RND)
 856                                 addr &= ~(SHMLBA-1);       /* round down */
 857                         else
 858 #ifndef __ARCH_FORCE_SHMLBA
 859                                 if (addr & ~PAGE_MASK)
 860 #endif
 861                                         goto out;
 862                 }
 863                 flags = MAP_SHARED | MAP_FIXED;
 864         } else {
 865                 if ((shmflg & SHM_REMAP))
 866                         goto out;
 867
 868                 flags = MAP_SHARED;
 869         }
 870
 871         if (shmflg & SHM_RDONLY) {
 872                 prot = PROT_READ;
 873                 acc_mode = S_IRUGO;
 874                 f_mode = FMODE_READ;
 875         } else {
 876                 prot = PROT_READ | PROT_WRITE;
 877                 acc_mode = S_IRUGO | S_IWUGO;
 878                 f_mode = FMODE_READ | FMODE_WRITE;
 879         }
 880         if (shmflg & SHM_EXEC) {
 881                 prot |= PROT_EXEC;
 882                 acc_mode |= S_IXUGO;
 883         }
 884
 885         /*
 886          * We cannot rely on the fs check since SYSV IPC does have an
 887          * additional creator id...
 888          */
 889         ns = current->nsproxy->ipc_ns;
 890         shp = shm_lock(ns, shmid);
 891         if(shp == NULL)
 892                 goto out;
 893
 894         err = shm_checkid(ns, shp,shmid);
 895         if (err)
 896                 goto out_unlock;
 897
 898         err = -EACCES;
 899         if (ipcperms(&shp->shm_perm, acc_mode))
 900                 goto out_unlock;
 901
 902         err = security_shm_shmat(shp, shmaddr, shmflg);
 903         if (err)
 904                 goto out_unlock;
 905
 906         path.dentry = dget(shp->shm_file->f_path.dentry);
 907         path.mnt    = mntget(shp->shm_file->f_path.mnt);
 908         shp->shm_nattch++;
 909         size = i_size_read(path.dentry->d_inode);
 910         shm_unlock(shp);
 911
 912         err = -ENOMEM;
 913         sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
 914         if (!sfd)
 915                 goto out_put_path;
 916
 917         err = -ENOMEM;
 918         file = get_empty_filp();
 919         if (!file)
 920                 goto out_free;
 921
 922         file->f_op = &shm_file_operations;
 923         file->private_data = sfd;
 924         file->f_path = path;
 925         file->f_mapping = shp->shm_file->f_mapping;
 926         file->f_mode = f_mode;
 927         sfd->id = shp->id;
 928         sfd->ns = get_ipc_ns(ns);
 929         sfd->file = shp->shm_file;
 930         sfd->vm_ops = NULL;
 931
 932         down_write(&current->mm->mmap_sem);
 933         if (addr && !(shmflg & SHM_REMAP)) {
 934                 err = -EINVAL;
 935                 if (find_vma_intersection(current->mm, addr, addr + size))
 936                         goto invalid;
 937                 /*
 938                  * If shm segment goes below stack, make sure there is some
 939                  * space left for the stack to grow (at least 4 pages).
 940                  */
 941                 if (addr < current->mm->start_stack &&
 942                     addr > current->mm->start_stack - size - PAGE_SIZE * 5)
 943                         goto invalid;
 944         }
 945
 946         user_addr = do_mmap (file, addr, size, prot, flags, 0);
 947         *raddr = user_addr;
 948         err = 0;
 949         if (IS_ERR_VALUE(user_addr))
 950                 err = (long)user_addr;
 951 invalid:
 952         up_write(&current->mm->mmap_sem);
 953
 954         fput(file);
 955
 956 out_nattch:
 957         mutex_lock(&shm_ids(ns).mutex);
 958         shp = shm_lock(ns, shmid);
 959         BUG_ON(!shp);
 960         shp->shm_nattch--;
 961         if(shp->shm_nattch == 0 &&
 962            shp->shm_perm.mode & SHM_DEST)
 963                 shm_destroy(ns, shp);
 964         else
 965                 shm_unlock(shp);
 966         mutex_unlock(&shm_ids(ns).mutex);
 967
 968 out:
 969         return err;
 970
 971 out_unlock:
 972         shm_unlock(shp);
 973         goto out;
 974
 975 out_free:
 976         kfree(sfd);
 977 out_put_path:
 978         dput(path.dentry);
 979         mntput(path.mnt);
 980         goto out_nattch;
 981 }
 982
 983 asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
 984 {
 985         unsigned long ret;
 986         long err;
 987
 988         err = do_shmat(shmid, shmaddr, shmflg, &ret);
 989         if (err)
 990                 return err;
 991         force_successful_syscall_return();
 992         return (long)ret;
 993 }
 994
 995 /*
 996  * detach and kill segment if marked destroyed.
 997  * The work is done in shm_close.
 998  */
 999 asmlinkage long sys_shmdt(char __user *shmaddr)
1000 {
1001         struct mm_struct *mm = current->mm;
1002         struct vm_area_struct *vma, *next;
1003         unsigned long addr = (unsigned long)shmaddr;
1004         loff_t size = 0;
1005         int retval = -EINVAL;
1006
1007         if (addr & ~PAGE_MASK)
1008                 return retval;
1009
1010         down_write(&mm->mmap_sem);
1011
1012         /*
1013          * This function tries to be smart and unmap shm segments that
1014          * were modified by partial mlock or munmap calls:
1015          * - It first determines the size of the shm segment that should be
1016          *   unmapped: It searches for a vma that is backed by shm and that
1017          *   started at address shmaddr. It records it's size and then unmaps
1018          *   it.
1019          * - Then it unmaps all shm vmas that started at shmaddr and that
1020          *   are within the initially determined size.
1021          * Errors from do_munmap are ignored: the function only fails if
1022          * it's called with invalid parameters or if it's called to unmap
1023          * a part of a vma. Both calls in this function are for full vmas,
1024          * the parameters are directly copied from the vma itself and always
1025          * valid - therefore do_munmap cannot fail. (famous last words?)
1026          */
1027         /*
1028          * If it had been mremap()'d, the starting address would not
1029          * match the usual checks anyway. So assume all vma's are
1030          * above the starting address given.
1031          */
1032         vma = find_vma(mm, addr);
1033
1034         while (vma) {
1035                 next = vma->vm_next;
1036
1037                 /*
1038                  * Check if the starting address would match, i.e. it's
1039                  * a fragment created by mprotect() and/or munmap(), or it
1040                  * otherwise it starts at this address with no hassles.
1041                  */
1042                 if ((vma->vm_ops == &shm_vm_ops) &&
1043                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1044
1045
1046                         size = vma->vm_file->f_path.dentry->d_inode->i_size;
1047                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1048                         /*
1049                          * We discovered the size of the shm segment, so
1050                          * break out of here and fall through to the next
1051                          * loop that uses the size information to stop
1052                          * searching for matching vma's.
1053                          */
1054                         retval = 0;
1055                         vma = next;
1056                         break;
1057                 }
1058                 vma = next;
1059         }
1060
1061         /*
1062          * We need look no further than the maximum address a fragment
1063          * could possibly have landed at. Also cast things to loff_t to
1064          * prevent overflows and make comparisions vs. equal-width types.
1065          */
1066         size = PAGE_ALIGN(size);
1067         while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1068                 next = vma->vm_next;
1069
1070                 /* finding a matching vma now does not alter retval */
1071                 if ((vma->vm_ops == &shm_vm_ops) &&
1072                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1073
1074                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1075                 vma = next;
1076         }
1077
1078         up_write(&mm->mmap_sem);
1079         return retval;
1080 }
1081
1082 #ifdef CONFIG_PROC_FS
1083 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1084 {
1085         struct shmid_kernel *shp = it;
1086         char *format;
1087
1088 #define SMALL_STRING "%10d %10d  %4o %10u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1089 #define BIG_STRING   "%10d %10d  %4o %21u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1090
1091         if (sizeof(size_t) <= sizeof(int))
1092                 format = SMALL_STRING;
1093         else
1094                 format = BIG_STRING;
1095         return seq_printf(s, format,
1096                           shp->shm_perm.key,
1097                           shp->id,
1098                           shp->shm_perm.mode,
1099                           shp->shm_segsz,
1100                           shp->shm_cprid,
1101                           shp->shm_lprid,
1102                           shp->shm_nattch,
1103                           shp->shm_perm.uid,
1104                           shp->shm_perm.gid,
1105                           shp->shm_perm.cuid,
1106                           shp->shm_perm.cgid,
1107                           shp->shm_atim,
1108                           shp->shm_dtim,
1109                           shp->shm_ctim);
1110 }
1111 #endif