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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 __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);
  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         struct shmid_kernel *shp;
 116         int next_id;
 117         int total, in_use;
 118
 119         mutex_lock(&shm_ids(ns).mutex);
 120
 121         in_use = shm_ids(ns).in_use;
 122
 123         for (total = 0, next_id = 0; total < in_use; next_id++) {
 124                 shp = idr_find(&shm_ids(ns).ipcs_idr, next_id);
 125                 if (shp == NULL)
 126                         continue;
 127                 ipc_lock_by_ptr(&shp->shm_perm);
 128                 do_shm_rmid(ns, shp);
 129                 total++;
 130         }
 131         mutex_unlock(&shm_ids(ns).mutex);
 132
 133         kfree(ns->ids[IPC_SHM_IDS]);
 134         ns->ids[IPC_SHM_IDS] = NULL;
 135 }
 136
 137 void __init shm_init (void)
 138 {
 139         __shm_init_ns(&init_ipc_ns, &init_shm_ids);
 140         ipc_init_proc_interface("sysvipc/shm",
 141                                 "       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime\n",
 142                                 IPC_SHM_IDS, sysvipc_shm_proc_show);
 143 }
 144
 145 static inline int shm_checkid(struct ipc_namespace *ns,
 146                 struct shmid_kernel *s, int id)
 147 {
 148         if (ipc_checkid(&shm_ids(ns), &s->shm_perm, id))
 149                 return -EIDRM;
 150         return 0;
 151 }
 152
 153 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
 154 {
 155         ipc_rmid(&shm_ids(ns), &s->shm_perm);
 156 }
 157
 158 static inline int shm_addid(struct ipc_namespace *ns, struct shmid_kernel *shp)
 159 {
 160         return ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
 161 }
 162
 163
 164
 165 /* This is called by fork, once for every shm attach. */
 166 static void shm_open(struct vm_area_struct *vma)
 167 {
 168         struct file *file = vma->vm_file;
 169         struct shm_file_data *sfd = shm_file_data(file);
 170         struct shmid_kernel *shp;
 171
 172         shp = shm_lock(sfd->ns, sfd->id);
 173         BUG_ON(!shp);
 174         shp->shm_atim = get_seconds();
 175         shp->shm_lprid = task_tgid_vnr(current);
 176         shp->shm_nattch++;
 177         shm_unlock(shp);
 178 }
 179
 180 /*
 181  * shm_destroy - free the struct shmid_kernel
 182  *
 183  * @shp: struct to free
 184  *
 185  * It has to be called with shp and shm_ids.mutex locked,
 186  * but returns with shp unlocked and freed.
 187  */
 188 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
 189 {
 190         ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
 191         shm_rmid(ns, shp);
 192         shm_unlock(shp);
 193         if (!is_file_hugepages(shp->shm_file))
 194                 shmem_lock(shp->shm_file, 0, shp->mlock_user);
 195         else
 196                 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
 197                                                 shp->mlock_user);
 198         fput (shp->shm_file);
 199         security_shm_free(shp);
 200         ipc_rcu_putref(shp);
 201 }
 202
 203 /*
 204  * remove the attach descriptor vma.
 205  * free memory for segment if it is marked destroyed.
 206  * The descriptor has already been removed from the current->mm->mmap list
 207  * and will later be kfree()d.
 208  */
 209 static void shm_close(struct vm_area_struct *vma)
 210 {
 211         struct file * file = vma->vm_file;
 212         struct shm_file_data *sfd = shm_file_data(file);
 213         struct shmid_kernel *shp;
 214         struct ipc_namespace *ns = sfd->ns;
 215
 216         mutex_lock(&shm_ids(ns).mutex);
 217         /* remove from the list of attaches of the shm segment */
 218         shp = shm_lock(ns, sfd->id);
 219         BUG_ON(!shp);
 220         shp->shm_lprid = task_tgid_vnr(current);
 221         shp->shm_dtim = get_seconds();
 222         shp->shm_nattch--;
 223         if(shp->shm_nattch == 0 &&
 224            shp->shm_perm.mode & SHM_DEST)
 225                 shm_destroy(ns, shp);
 226         else
 227                 shm_unlock(shp);
 228         mutex_unlock(&shm_ids(ns).mutex);
 229 }
 230
 231 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 232 {
 233         struct file *file = vma->vm_file;
 234         struct shm_file_data *sfd = shm_file_data(file);
 235
 236         return sfd->vm_ops->fault(vma, vmf);
 237 }
 238
 239 #ifdef CONFIG_NUMA
 240 static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
 241 {
 242         struct file *file = vma->vm_file;
 243         struct shm_file_data *sfd = shm_file_data(file);
 244         int err = 0;
 245         if (sfd->vm_ops->set_policy)
 246                 err = sfd->vm_ops->set_policy(vma, new);
 247         return err;
 248 }
 249
 250 static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
 251                                         unsigned long addr)
 252 {
 253         struct file *file = vma->vm_file;
 254         struct shm_file_data *sfd = shm_file_data(file);
 255         struct mempolicy *pol = NULL;
 256
 257         if (sfd->vm_ops->get_policy)
 258                 pol = sfd->vm_ops->get_policy(vma, addr);
 259         else if (vma->vm_policy)
 260                 pol = vma->vm_policy;
 261         else
 262                 pol = current->mempolicy;
 263         return pol;
 264 }
 265 #endif
 266
 267 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
 268 {
 269         struct shm_file_data *sfd = shm_file_data(file);
 270         int ret;
 271
 272         ret = sfd->file->f_op->mmap(sfd->file, vma);
 273         if (ret != 0)
 274                 return ret;
 275         sfd->vm_ops = vma->vm_ops;
 276 #ifdef CONFIG_MMU
 277         BUG_ON(!sfd->vm_ops->fault);
 278 #endif
 279         vma->vm_ops = &shm_vm_ops;
 280         shm_open(vma);
 281
 282         return ret;
 283 }
 284
 285 static int shm_release(struct inode *ino, struct file *file)
 286 {
 287         struct shm_file_data *sfd = shm_file_data(file);
 288
 289         put_ipc_ns(sfd->ns);
 290         shm_file_data(file) = NULL;
 291         kfree(sfd);
 292         return 0;
 293 }
 294
 295 static int shm_fsync(struct file *file, struct dentry *dentry, int datasync)
 296 {
 297         int (*fsync) (struct file *, struct dentry *, int datasync);
 298         struct shm_file_data *sfd = shm_file_data(file);
 299         int ret = -EINVAL;
 300
 301         fsync = sfd->file->f_op->fsync;
 302         if (fsync)
 303                 ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync);
 304         return ret;
 305 }
 306
 307 static unsigned long shm_get_unmapped_area(struct file *file,
 308         unsigned long addr, unsigned long len, unsigned long pgoff,
 309         unsigned long flags)
 310 {
 311         struct shm_file_data *sfd = shm_file_data(file);
 312         return get_unmapped_area(sfd->file, addr, len, pgoff, flags);
 313 }
 314
 315 int is_file_shm_hugepages(struct file *file)
 316 {
 317         int ret = 0;
 318
 319         if (file->f_op == &shm_file_operations) {
 320                 struct shm_file_data *sfd;
 321                 sfd = shm_file_data(file);
 322                 ret = is_file_hugepages(sfd->file);
 323         }
 324         return ret;
 325 }
 326
 327 static const struct file_operations shm_file_operations = {
 328         .mmap           = shm_mmap,
 329         .fsync          = shm_fsync,
 330         .release        = shm_release,
 331         .get_unmapped_area      = shm_get_unmapped_area,
 332 };
 333
 334 static struct vm_operations_struct shm_vm_ops = {
 335         .open   = shm_open,     /* callback for a new vm-area open */
 336         .close  = shm_close,    /* callback for when the vm-area is released */
 337         .fault  = shm_fault,
 338 #if defined(CONFIG_NUMA)
 339         .set_policy = shm_set_policy,
 340         .get_policy = shm_get_policy,
 341 #endif
 342 };
 343
 344 static int newseg (struct ipc_namespace *ns, key_t key, int shmflg, size_t size)
 345 {
 346         int error;
 347         struct shmid_kernel *shp;
 348         int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
 349         struct file * file;
 350         char name[13];
 351         int id;
 352
 353         if (size < SHMMIN || size > ns->shm_ctlmax)
 354                 return -EINVAL;
 355
 356         if (ns->shm_tot + numpages > ns->shm_ctlall)
 357                 return -ENOSPC;
 358
 359         shp = ipc_rcu_alloc(sizeof(*shp));
 360         if (!shp)
 361                 return -ENOMEM;
 362
 363         shp->shm_perm.key = key;
 364         shp->shm_perm.mode = (shmflg & S_IRWXUGO);
 365         shp->mlock_user = NULL;
 366
 367         shp->shm_perm.security = NULL;
 368         error = security_shm_alloc(shp);
 369         if (error) {
 370                 ipc_rcu_putref(shp);
 371                 return error;
 372         }
 373
 374         sprintf (name, "SYSV%08x", key);
 375         if (shmflg & SHM_HUGETLB) {
 376                 /* hugetlb_file_setup takes care of mlock user accounting */
 377                 file = hugetlb_file_setup(name, size);
 378                 shp->mlock_user = current->user;
 379         } else {
 380                 int acctflag = VM_ACCOUNT;
 381                 /*
 382                  * Do not allow no accounting for OVERCOMMIT_NEVER, even
 383                  * if it's asked for.
 384                  */
 385                 if  ((shmflg & SHM_NORESERVE) &&
 386                                 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
 387                         acctflag = 0;
 388                 file = shmem_file_setup(name, size, acctflag);
 389         }
 390         error = PTR_ERR(file);
 391         if (IS_ERR(file))
 392                 goto no_file;
 393
 394         error = -ENOSPC;
 395         id = shm_addid(ns, shp);
 396         if(id == -1)
 397                 goto no_id;
 398
 399         shp->shm_cprid = task_tgid_vnr(current);
 400         shp->shm_lprid = 0;
 401         shp->shm_atim = shp->shm_dtim = 0;
 402         shp->shm_ctim = get_seconds();
 403         shp->shm_segsz = size;
 404         shp->shm_nattch = 0;
 405         shp->shm_perm.id = shm_buildid(ns, id, shp->shm_perm.seq);
 406         shp->shm_file = file;
 407         /*
 408          * shmid gets reported as "inode#" in /proc/pid/maps.
 409          * proc-ps tools use this. Changing this will break them.
 410          */
 411         file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
 412
 413         ns->shm_tot += numpages;
 414         error = shp->shm_perm.id;
 415         shm_unlock(shp);
 416         return error;
 417
 418 no_id:
 419         fput(file);
 420 no_file:
 421         security_shm_free(shp);
 422         ipc_rcu_putref(shp);
 423         return error;
 424 }
 425
 426 asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
 427 {
 428         struct shmid_kernel *shp;
 429         int err;
 430         struct ipc_namespace *ns;
 431
 432         ns = current->nsproxy->ipc_ns;
 433
 434         err = idr_pre_get(&shm_ids(ns).ipcs_idr, GFP_KERNEL);
 435
 436         if (key == IPC_PRIVATE) {
 437                 if (!err)
 438                         err = -ENOMEM;
 439                 else {
 440                         mutex_lock(&shm_ids(ns).mutex);
 441                         err = newseg(ns, key, shmflg, size);
 442                         mutex_unlock(&shm_ids(ns).mutex);
 443                 }
 444         } else {
 445                 mutex_lock(&shm_ids(ns).mutex);
 446                 shp = (struct shmid_kernel *) ipc_findkey(&shm_ids(ns), key);
 447                 if (shp == NULL) {
 448                         if (!(shmflg & IPC_CREAT))
 449                                 err = -ENOENT;
 450                         else if (!err)
 451                                 err = -ENOMEM;
 452                         else
 453                                 err = newseg(ns, key, shmflg, size);
 454                 } else {
 455                         /* shp has been locked by ipc_findkey() */
 456
 457                         if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL))
 458                                 err = -EEXIST;
 459                         else {
 460                                 if (shp->shm_segsz < size)
 461                                         err = -EINVAL;
 462                                 else if (ipcperms(&shp->shm_perm, shmflg))
 463                                         err = -EACCES;
 464                                 else {
 465                                         err = security_shm_associate(shp,
 466                                                                 shmflg);
 467                                         if (!err)
 468                                                 err = shp->shm_perm.id;
 469                                 }
 470                         }
 471                         shm_unlock(shp);
 472                 }
 473                 mutex_unlock(&shm_ids(ns).mutex);
 474         }
 475
 476         return err;
 477 }
 478
 479 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
 480 {
 481         switch(version) {
 482         case IPC_64:
 483                 return copy_to_user(buf, in, sizeof(*in));
 484         case IPC_OLD:
 485             {
 486                 struct shmid_ds out;
 487
 488                 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
 489                 out.shm_segsz   = in->shm_segsz;
 490                 out.shm_atime   = in->shm_atime;
 491                 out.shm_dtime   = in->shm_dtime;
 492                 out.shm_ctime   = in->shm_ctime;
 493                 out.shm_cpid    = in->shm_cpid;
 494                 out.shm_lpid    = in->shm_lpid;
 495                 out.shm_nattch  = in->shm_nattch;
 496
 497                 return copy_to_user(buf, &out, sizeof(out));
 498             }
 499         default:
 500                 return -EINVAL;
 501         }
 502 }
 503
 504 struct shm_setbuf {
 505         uid_t   uid;
 506         gid_t   gid;
 507         mode_t  mode;
 508 };
 509
 510 static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
 511 {
 512         switch(version) {
 513         case IPC_64:
 514             {
 515                 struct shmid64_ds tbuf;
 516
 517                 if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
 518                         return -EFAULT;
 519
 520                 out->uid        = tbuf.shm_perm.uid;
 521                 out->gid        = tbuf.shm_perm.gid;
 522                 out->mode       = tbuf.shm_perm.mode;
 523
 524                 return 0;
 525             }
 526         case IPC_OLD:
 527             {
 528                 struct shmid_ds tbuf_old;
 529
 530                 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
 531                         return -EFAULT;
 532
 533                 out->uid        = tbuf_old.shm_perm.uid;
 534                 out->gid        = tbuf_old.shm_perm.gid;
 535                 out->mode       = tbuf_old.shm_perm.mode;
 536
 537                 return 0;
 538             }
 539         default:
 540                 return -EINVAL;
 541         }
 542 }
 543
 544 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
 545 {
 546         switch(version) {
 547         case IPC_64:
 548                 return copy_to_user(buf, in, sizeof(*in));
 549         case IPC_OLD:
 550             {
 551                 struct shminfo out;
 552
 553                 if(in->shmmax > INT_MAX)
 554                         out.shmmax = INT_MAX;
 555                 else
 556                         out.shmmax = (int)in->shmmax;
 557
 558                 out.shmmin      = in->shmmin;
 559                 out.shmmni      = in->shmmni;
 560                 out.shmseg      = in->shmseg;
 561                 out.shmall      = in->shmall;
 562
 563                 return copy_to_user(buf, &out, sizeof(out));
 564             }
 565         default:
 566                 return -EINVAL;
 567         }
 568 }
 569
 570 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
 571                 unsigned long *swp)
 572 {
 573         int next_id;
 574         int total, in_use;
 575
 576         *rss = 0;
 577         *swp = 0;
 578
 579         in_use = shm_ids(ns).in_use;
 580
 581         for (total = 0, next_id = 0; total < in_use; next_id++) {
 582                 struct shmid_kernel *shp;
 583                 struct inode *inode;
 584
 585                 shp = shm_get(ns, next_id);
 586                 if (shp == NULL)
 587                         continue;
 588
 589                 inode = shp->shm_file->f_path.dentry->d_inode;
 590
 591                 if (is_file_hugepages(shp->shm_file)) {
 592                         struct address_space *mapping = inode->i_mapping;
 593                         *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
 594                 } else {
 595                         struct shmem_inode_info *info = SHMEM_I(inode);
 596                         spin_lock(&info->lock);
 597                         *rss += inode->i_mapping->nrpages;
 598                         *swp += info->swapped;
 599                         spin_unlock(&info->lock);
 600                 }
 601
 602                 total++;
 603         }
 604 }
 605
 606 asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
 607 {
 608         struct shm_setbuf setbuf;
 609         struct shmid_kernel *shp;
 610         int err, version;
 611         struct ipc_namespace *ns;
 612
 613         if (cmd < 0 || shmid < 0) {
 614                 err = -EINVAL;
 615                 goto out;
 616         }
 617
 618         version = ipc_parse_version(&cmd);
 619         ns = current->nsproxy->ipc_ns;
 620
 621         switch (cmd) { /* replace with proc interface ? */
 622         case IPC_INFO:
 623         {
 624                 struct shminfo64 shminfo;
 625
 626                 err = security_shm_shmctl(NULL, cmd);
 627                 if (err)
 628                         return err;
 629
 630                 memset(&shminfo,0,sizeof(shminfo));
 631                 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
 632                 shminfo.shmmax = ns->shm_ctlmax;
 633                 shminfo.shmall = ns->shm_ctlall;
 634
 635                 shminfo.shmmin = SHMMIN;
 636                 if(copy_shminfo_to_user (buf, &shminfo, version))
 637                         return -EFAULT;
 638                 /* reading a integer is always atomic */
 639                 err = ipc_get_maxid(&shm_ids(ns));
 640                 if(err<0)
 641                         err = 0;
 642                 goto out;
 643         }
 644         case SHM_INFO:
 645         {
 646                 struct shm_info shm_info;
 647
 648                 err = security_shm_shmctl(NULL, cmd);
 649                 if (err)
 650                         return err;
 651
 652                 memset(&shm_info,0,sizeof(shm_info));
 653                 mutex_lock(&shm_ids(ns).mutex);
 654                 shm_info.used_ids = shm_ids(ns).in_use;
 655                 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
 656                 shm_info.shm_tot = ns->shm_tot;
 657                 shm_info.swap_attempts = 0;
 658                 shm_info.swap_successes = 0;
 659                 err = ipc_get_maxid(&shm_ids(ns));
 660                 mutex_unlock(&shm_ids(ns).mutex);
 661                 if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
 662                         err = -EFAULT;
 663                         goto out;
 664                 }
 665
 666                 err = err < 0 ? 0 : err;
 667                 goto out;
 668         }
 669         case SHM_STAT:
 670         case IPC_STAT:
 671         {
 672                 struct shmid64_ds tbuf;
 673                 int result;
 674                 memset(&tbuf, 0, sizeof(tbuf));
 675                 shp = shm_lock(ns, shmid);
 676                 if(shp==NULL) {
 677                         err = -EINVAL;
 678                         goto out;
 679                 } else if (cmd == SHM_STAT) {
 680                         result = shp->shm_perm.id;
 681                 } else {
 682                         err = shm_checkid(ns, shp,shmid);
 683                         if(err)
 684                                 goto out_unlock;
 685                         result = 0;
 686                 }
 687                 err=-EACCES;
 688                 if (ipcperms (&shp->shm_perm, S_IRUGO))
 689                         goto out_unlock;
 690                 err = security_shm_shmctl(shp, cmd);
 691                 if (err)
 692                         goto out_unlock;
 693                 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
 694                 tbuf.shm_segsz  = shp->shm_segsz;
 695                 tbuf.shm_atime  = shp->shm_atim;
 696                 tbuf.shm_dtime  = shp->shm_dtim;
 697                 tbuf.shm_ctime  = shp->shm_ctim;
 698                 tbuf.shm_cpid   = shp->shm_cprid;
 699                 tbuf.shm_lpid   = shp->shm_lprid;
 700                 tbuf.shm_nattch = shp->shm_nattch;
 701                 shm_unlock(shp);
 702                 if(copy_shmid_to_user (buf, &tbuf, version))
 703                         err = -EFAULT;
 704                 else
 705                         err = result;
 706                 goto out;
 707         }
 708         case SHM_LOCK:
 709         case SHM_UNLOCK:
 710         {
 711                 shp = shm_lock(ns, shmid);
 712                 if(shp==NULL) {
 713                         err = -EINVAL;
 714                         goto out;
 715                 }
 716                 err = shm_checkid(ns, shp,shmid);
 717                 if(err)
 718                         goto out_unlock;
 719
 720                 err = audit_ipc_obj(&(shp->shm_perm));
 721                 if (err)
 722                         goto out_unlock;
 723
 724                 if (!capable(CAP_IPC_LOCK)) {
 725                         err = -EPERM;
 726                         if (current->euid != shp->shm_perm.uid &&
 727                             current->euid != shp->shm_perm.cuid)
 728                                 goto out_unlock;
 729                         if (cmd == SHM_LOCK &&
 730                             !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
 731                                 goto out_unlock;
 732                 }
 733
 734                 err = security_shm_shmctl(shp, cmd);
 735                 if (err)
 736                         goto out_unlock;
 737
 738                 if(cmd==SHM_LOCK) {
 739                         struct user_struct * user = current->user;
 740                         if (!is_file_hugepages(shp->shm_file)) {
 741                                 err = shmem_lock(shp->shm_file, 1, user);
 742                                 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
 743                                         shp->shm_perm.mode |= SHM_LOCKED;
 744                                         shp->mlock_user = user;
 745                                 }
 746                         }
 747                 } else if (!is_file_hugepages(shp->shm_file)) {
 748                         shmem_lock(shp->shm_file, 0, shp->mlock_user);
 749                         shp->shm_perm.mode &= ~SHM_LOCKED;
 750                         shp->mlock_user = NULL;
 751                 }
 752                 shm_unlock(shp);
 753                 goto out;
 754         }
 755         case IPC_RMID:
 756         {
 757                 /*
 758                  *      We cannot simply remove the file. The SVID states
 759                  *      that the block remains until the last person
 760                  *      detaches from it, then is deleted. A shmat() on
 761                  *      an RMID segment is legal in older Linux and if
 762                  *      we change it apps break...
 763                  *
 764                  *      Instead we set a destroyed flag, and then blow
 765                  *      the name away when the usage hits zero.
 766                  */
 767                 mutex_lock(&shm_ids(ns).mutex);
 768                 shp = shm_lock(ns, shmid);
 769                 err = -EINVAL;
 770                 if (shp == NULL)
 771                         goto out_up;
 772                 err = shm_checkid(ns, shp, shmid);
 773                 if(err)
 774                         goto out_unlock_up;
 775
 776                 err = audit_ipc_obj(&(shp->shm_perm));
 777                 if (err)
 778                         goto out_unlock_up;
 779
 780                 if (current->euid != shp->shm_perm.uid &&
 781                     current->euid != shp->shm_perm.cuid &&
 782                     !capable(CAP_SYS_ADMIN)) {
 783                         err=-EPERM;
 784                         goto out_unlock_up;
 785                 }
 786
 787                 err = security_shm_shmctl(shp, cmd);
 788                 if (err)
 789                         goto out_unlock_up;
 790
 791                 do_shm_rmid(ns, shp);
 792                 mutex_unlock(&shm_ids(ns).mutex);
 793                 goto out;
 794         }
 795
 796         case IPC_SET:
 797         {
 798                 if (copy_shmid_from_user (&setbuf, buf, version)) {
 799                         err = -EFAULT;
 800                         goto out;
 801                 }
 802                 mutex_lock(&shm_ids(ns).mutex);
 803                 shp = shm_lock(ns, shmid);
 804                 err=-EINVAL;
 805                 if(shp==NULL)
 806                         goto out_up;
 807                 err = shm_checkid(ns, shp,shmid);
 808                 if(err)
 809                         goto out_unlock_up;
 810                 err = audit_ipc_obj(&(shp->shm_perm));
 811                 if (err)
 812                         goto out_unlock_up;
 813                 err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode);
 814                 if (err)
 815                         goto out_unlock_up;
 816                 err=-EPERM;
 817                 if (current->euid != shp->shm_perm.uid &&
 818                     current->euid != shp->shm_perm.cuid &&
 819                     !capable(CAP_SYS_ADMIN)) {
 820                         goto out_unlock_up;
 821                 }
 822
 823                 err = security_shm_shmctl(shp, cmd);
 824                 if (err)
 825                         goto out_unlock_up;
 826
 827                 shp->shm_perm.uid = setbuf.uid;
 828                 shp->shm_perm.gid = setbuf.gid;
 829                 shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO)
 830                         | (setbuf.mode & S_IRWXUGO);
 831                 shp->shm_ctim = get_seconds();
 832                 break;
 833         }
 834
 835         default:
 836                 err = -EINVAL;
 837                 goto out;
 838         }
 839
 840         err = 0;
 841 out_unlock_up:
 842         shm_unlock(shp);
 843 out_up:
 844         mutex_unlock(&shm_ids(ns).mutex);
 845         goto out;
 846 out_unlock:
 847         shm_unlock(shp);
 848 out:
 849         return err;
 850 }
 851
 852 /*
 853  * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
 854  *
 855  * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
 856  * "raddr" thing points to kernel space, and there has to be a wrapper around
 857  * this.
 858  */
 859 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
 860 {
 861         struct shmid_kernel *shp;
 862         unsigned long addr;
 863         unsigned long size;
 864         struct file * file;
 865         int    err;
 866         unsigned long flags;
 867         unsigned long prot;
 868         int acc_mode;
 869         unsigned long user_addr;
 870         struct ipc_namespace *ns;
 871         struct shm_file_data *sfd;
 872         struct path path;
 873         mode_t f_mode;
 874
 875         err = -EINVAL;
 876         if (shmid < 0)
 877                 goto out;
 878         else if ((addr = (ulong)shmaddr)) {
 879                 if (addr & (SHMLBA-1)) {
 880                         if (shmflg & SHM_RND)
 881                                 addr &= ~(SHMLBA-1);       /* round down */
 882                         else
 883 #ifndef __ARCH_FORCE_SHMLBA
 884                                 if (addr & ~PAGE_MASK)
 885 #endif
 886                                         goto out;
 887                 }
 888                 flags = MAP_SHARED | MAP_FIXED;
 889         } else {
 890                 if ((shmflg & SHM_REMAP))
 891                         goto out;
 892
 893                 flags = MAP_SHARED;
 894         }
 895
 896         if (shmflg & SHM_RDONLY) {
 897                 prot = PROT_READ;
 898                 acc_mode = S_IRUGO;
 899                 f_mode = FMODE_READ;
 900         } else {
 901                 prot = PROT_READ | PROT_WRITE;
 902                 acc_mode = S_IRUGO | S_IWUGO;
 903                 f_mode = FMODE_READ | FMODE_WRITE;
 904         }
 905         if (shmflg & SHM_EXEC) {
 906                 prot |= PROT_EXEC;
 907                 acc_mode |= S_IXUGO;
 908         }
 909
 910         /*
 911          * We cannot rely on the fs check since SYSV IPC does have an
 912          * additional creator id...
 913          */
 914         ns = current->nsproxy->ipc_ns;
 915         shp = shm_lock(ns, shmid);
 916         if(shp == NULL)
 917                 goto out;
 918
 919         err = shm_checkid(ns, shp,shmid);
 920         if (err)
 921                 goto out_unlock;
 922
 923         err = -EACCES;
 924         if (ipcperms(&shp->shm_perm, acc_mode))
 925                 goto out_unlock;
 926
 927         err = security_shm_shmat(shp, shmaddr, shmflg);
 928         if (err)
 929                 goto out_unlock;
 930
 931         path.dentry = dget(shp->shm_file->f_path.dentry);
 932         path.mnt    = shp->shm_file->f_path.mnt;
 933         shp->shm_nattch++;
 934         size = i_size_read(path.dentry->d_inode);
 935         shm_unlock(shp);
 936
 937         err = -ENOMEM;
 938         sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
 939         if (!sfd)
 940                 goto out_put_dentry;
 941
 942         err = -ENOMEM;
 943
 944         file = alloc_file(path.mnt, path.dentry, f_mode, &shm_file_operations);
 945         if (!file)
 946                 goto out_free;
 947
 948         file->private_data = sfd;
 949         file->f_mapping = shp->shm_file->f_mapping;
 950         sfd->id = shp->shm_perm.id;
 951         sfd->ns = get_ipc_ns(ns);
 952         sfd->file = shp->shm_file;
 953         sfd->vm_ops = NULL;
 954
 955         down_write(&current->mm->mmap_sem);
 956         if (addr && !(shmflg & SHM_REMAP)) {
 957                 err = -EINVAL;
 958                 if (find_vma_intersection(current->mm, addr, addr + size))
 959                         goto invalid;
 960                 /*
 961                  * If shm segment goes below stack, make sure there is some
 962                  * space left for the stack to grow (at least 4 pages).
 963                  */
 964                 if (addr < current->mm->start_stack &&
 965                     addr > current->mm->start_stack - size - PAGE_SIZE * 5)
 966                         goto invalid;
 967         }
 968
 969         user_addr = do_mmap (file, addr, size, prot, flags, 0);
 970         *raddr = user_addr;
 971         err = 0;
 972         if (IS_ERR_VALUE(user_addr))
 973                 err = (long)user_addr;
 974 invalid:
 975         up_write(&current->mm->mmap_sem);
 976
 977         fput(file);
 978
 979 out_nattch:
 980         mutex_lock(&shm_ids(ns).mutex);
 981         shp = shm_lock(ns, shmid);
 982         BUG_ON(!shp);
 983         shp->shm_nattch--;
 984         if(shp->shm_nattch == 0 &&
 985            shp->shm_perm.mode & SHM_DEST)
 986                 shm_destroy(ns, shp);
 987         else
 988                 shm_unlock(shp);
 989         mutex_unlock(&shm_ids(ns).mutex);
 990
 991 out:
 992         return err;
 993
 994 out_unlock:
 995         shm_unlock(shp);
 996         goto out;
 997
 998 out_free:
 999         kfree(sfd);
1000 out_put_dentry:
1001         dput(path.dentry);
1002         goto out_nattch;
1003 }
1004
1005 asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
1006 {
1007         unsigned long ret;
1008         long err;
1009
1010         err = do_shmat(shmid, shmaddr, shmflg, &ret);
1011         if (err)
1012                 return err;
1013         force_successful_syscall_return();
1014         return (long)ret;
1015 }
1016
1017 /*
1018  * detach and kill segment if marked destroyed.
1019  * The work is done in shm_close.
1020  */
1021 asmlinkage long sys_shmdt(char __user *shmaddr)
1022 {
1023         struct mm_struct *mm = current->mm;
1024         struct vm_area_struct *vma, *next;
1025         unsigned long addr = (unsigned long)shmaddr;
1026         loff_t size = 0;
1027         int retval = -EINVAL;
1028
1029         if (addr & ~PAGE_MASK)
1030                 return retval;
1031
1032         down_write(&mm->mmap_sem);
1033
1034         /*
1035          * This function tries to be smart and unmap shm segments that
1036          * were modified by partial mlock or munmap calls:
1037          * - It first determines the size of the shm segment that should be
1038          *   unmapped: It searches for a vma that is backed by shm and that
1039          *   started at address shmaddr. It records it's size and then unmaps
1040          *   it.
1041          * - Then it unmaps all shm vmas that started at shmaddr and that
1042          *   are within the initially determined size.
1043          * Errors from do_munmap are ignored: the function only fails if
1044          * it's called with invalid parameters or if it's called to unmap
1045          * a part of a vma. Both calls in this function are for full vmas,
1046          * the parameters are directly copied from the vma itself and always
1047          * valid - therefore do_munmap cannot fail. (famous last words?)
1048          */
1049         /*
1050          * If it had been mremap()'d, the starting address would not
1051          * match the usual checks anyway. So assume all vma's are
1052          * above the starting address given.
1053          */
1054         vma = find_vma(mm, addr);
1055
1056         while (vma) {
1057                 next = vma->vm_next;
1058
1059                 /*
1060                  * Check if the starting address would match, i.e. it's
1061                  * a fragment created by mprotect() and/or munmap(), or it
1062                  * otherwise it starts at this address with no hassles.
1063                  */
1064                 if ((vma->vm_ops == &shm_vm_ops) &&
1065                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1066
1067
1068                         size = vma->vm_file->f_path.dentry->d_inode->i_size;
1069                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1070                         /*
1071                          * We discovered the size of the shm segment, so
1072                          * break out of here and fall through to the next
1073                          * loop that uses the size information to stop
1074                          * searching for matching vma's.
1075                          */
1076                         retval = 0;
1077                         vma = next;
1078                         break;
1079                 }
1080                 vma = next;
1081         }
1082
1083         /*
1084          * We need look no further than the maximum address a fragment
1085          * could possibly have landed at. Also cast things to loff_t to
1086          * prevent overflows and make comparisions vs. equal-width types.
1087          */
1088         size = PAGE_ALIGN(size);
1089         while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1090                 next = vma->vm_next;
1091
1092                 /* finding a matching vma now does not alter retval */
1093                 if ((vma->vm_ops == &shm_vm_ops) &&
1094                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1095
1096                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1097                 vma = next;
1098         }
1099
1100         up_write(&mm->mmap_sem);
1101         return retval;
1102 }
1103
1104 #ifdef CONFIG_PROC_FS
1105 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1106 {
1107         struct shmid_kernel *shp = it;
1108         char *format;
1109
1110 #define SMALL_STRING "%10d %10d  %4o %10u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1111 #define BIG_STRING   "%10d %10d  %4o %21u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1112
1113         if (sizeof(size_t) <= sizeof(int))
1114                 format = SMALL_STRING;
1115         else
1116                 format = BIG_STRING;
1117         return seq_printf(s, format,
1118                           shp->shm_perm.key,
1119                           shp->shm_perm.id,
1120                           shp->shm_perm.mode,
1121                           shp->shm_segsz,
1122                           shp->shm_cprid,
1123                           shp->shm_lprid,
1124                           shp->shm_nattch,
1125                           shp->shm_perm.uid,
1126                           shp->shm_perm.gid,
1127                           shp->shm_perm.cuid,
1128                           shp->shm_perm.cgid,
1129                           shp->shm_atim,
1130                           shp->shm_dtim,
1131                           shp->shm_ctim);
1132 }
1133 #endif