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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_unlock(shp)                 \
  63         ipc_unlock(&(shp)->shm_perm)
  64 #define shm_buildid(ns, id, seq)        \
  65         ipc_buildid(&shm_ids(ns), id, seq)
  66
  67 static int newseg(struct ipc_namespace *, struct ipc_params *);
  68 static void shm_open(struct vm_area_struct *vma);
  69 static void shm_close(struct vm_area_struct *vma);
  70 static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
  71 #ifdef CONFIG_PROC_FS
  72 static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
  73 #endif
  74
  75 static void __shm_init_ns(struct ipc_namespace *ns, struct ipc_ids *ids)
  76 {
  77         ns->ids[IPC_SHM_IDS] = ids;
  78         ns->shm_ctlmax = SHMMAX;
  79         ns->shm_ctlall = SHMALL;
  80         ns->shm_ctlmni = SHMMNI;
  81         ns->shm_tot = 0;
  82         ipc_init_ids(ids);
  83 }
  84
  85 static void do_shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *shp)
  86 {
  87         if (shp->shm_nattch){
  88                 shp->shm_perm.mode |= SHM_DEST;
  89                 /* Do not find it any more */
  90                 shp->shm_perm.key = IPC_PRIVATE;
  91                 shm_unlock(shp);
  92         } else
  93                 shm_destroy(ns, shp);
  94 }
  95
  96 int shm_init_ns(struct ipc_namespace *ns)
  97 {
  98         struct ipc_ids *ids;
  99
 100         ids = kmalloc(sizeof(struct ipc_ids), GFP_KERNEL);
 101         if (ids == NULL)
 102                 return -ENOMEM;
 103
 104         __shm_init_ns(ns, ids);
 105         return 0;
 106 }
 107
 108 void shm_exit_ns(struct ipc_namespace *ns)
 109 {
 110         struct shmid_kernel *shp;
 111         int next_id;
 112         int total, in_use;
 113
 114         mutex_lock(&shm_ids(ns).mutex);
 115
 116         in_use = shm_ids(ns).in_use;
 117
 118         for (total = 0, next_id = 0; total < in_use; next_id++) {
 119                 shp = idr_find(&shm_ids(ns).ipcs_idr, next_id);
 120                 if (shp == NULL)
 121                         continue;
 122                 ipc_lock_by_ptr(&shp->shm_perm);
 123                 do_shm_rmid(ns, shp);
 124                 total++;
 125         }
 126         mutex_unlock(&shm_ids(ns).mutex);
 127
 128         kfree(ns->ids[IPC_SHM_IDS]);
 129         ns->ids[IPC_SHM_IDS] = NULL;
 130 }
 131
 132 void __init shm_init (void)
 133 {
 134         __shm_init_ns(&init_ipc_ns, &init_shm_ids);
 135         ipc_init_proc_interface("sysvipc/shm",
 136                                 "       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime\n",
 137                                 IPC_SHM_IDS, sysvipc_shm_proc_show);
 138 }
 139
 140 static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
 141 {
 142         struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
 143
 144         return container_of(ipcp, struct shmid_kernel, shm_perm);
 145 }
 146
 147 static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
 148                                                 int id)
 149 {
 150         struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id);
 151
 152         return container_of(ipcp, struct shmid_kernel, shm_perm);
 153 }
 154
 155 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
 156 {
 157         ipc_rmid(&shm_ids(ns), &s->shm_perm);
 158 }
 159
 160 static inline int shm_addid(struct ipc_namespace *ns, struct shmid_kernel *shp)
 161 {
 162         return ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
 163 }
 164
 165
 166
 167 /* This is called by fork, once for every shm attach. */
 168 static void shm_open(struct vm_area_struct *vma)
 169 {
 170         struct file *file = vma->vm_file;
 171         struct shm_file_data *sfd = shm_file_data(file);
 172         struct shmid_kernel *shp;
 173
 174         shp = shm_lock(sfd->ns, sfd->id);
 175         BUG_ON(IS_ERR(shp));
 176         shp->shm_atim = get_seconds();
 177         shp->shm_lprid = task_tgid_vnr(current);
 178         shp->shm_nattch++;
 179         shm_unlock(shp);
 180 }
 181
 182 /*
 183  * shm_destroy - free the struct shmid_kernel
 184  *
 185  * @shp: struct to free
 186  *
 187  * It has to be called with shp and shm_ids.mutex locked,
 188  * but returns with shp unlocked and freed.
 189  */
 190 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
 191 {
 192         ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
 193         shm_rmid(ns, shp);
 194         shm_unlock(shp);
 195         if (!is_file_hugepages(shp->shm_file))
 196                 shmem_lock(shp->shm_file, 0, shp->mlock_user);
 197         else
 198                 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
 199                                                 shp->mlock_user);
 200         fput (shp->shm_file);
 201         security_shm_free(shp);
 202         ipc_rcu_putref(shp);
 203 }
 204
 205 /*
 206  * remove the attach descriptor vma.
 207  * free memory for segment if it is marked destroyed.
 208  * The descriptor has already been removed from the current->mm->mmap list
 209  * and will later be kfree()d.
 210  */
 211 static void shm_close(struct vm_area_struct *vma)
 212 {
 213         struct file * file = vma->vm_file;
 214         struct shm_file_data *sfd = shm_file_data(file);
 215         struct shmid_kernel *shp;
 216         struct ipc_namespace *ns = sfd->ns;
 217
 218         mutex_lock(&shm_ids(ns).mutex);
 219         /* remove from the list of attaches of the shm segment */
 220         shp = shm_lock(ns, sfd->id);
 221         BUG_ON(IS_ERR(shp));
 222         shp->shm_lprid = task_tgid_vnr(current);
 223         shp->shm_dtim = get_seconds();
 224         shp->shm_nattch--;
 225         if(shp->shm_nattch == 0 &&
 226            shp->shm_perm.mode & SHM_DEST)
 227                 shm_destroy(ns, shp);
 228         else
 229                 shm_unlock(shp);
 230         mutex_unlock(&shm_ids(ns).mutex);
 231 }
 232
 233 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 234 {
 235         struct file *file = vma->vm_file;
 236         struct shm_file_data *sfd = shm_file_data(file);
 237
 238         return sfd->vm_ops->fault(vma, vmf);
 239 }
 240
 241 #ifdef CONFIG_NUMA
 242 static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
 243 {
 244         struct file *file = vma->vm_file;
 245         struct shm_file_data *sfd = shm_file_data(file);
 246         int err = 0;
 247         if (sfd->vm_ops->set_policy)
 248                 err = sfd->vm_ops->set_policy(vma, new);
 249         return err;
 250 }
 251
 252 static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
 253                                         unsigned long addr)
 254 {
 255         struct file *file = vma->vm_file;
 256         struct shm_file_data *sfd = shm_file_data(file);
 257         struct mempolicy *pol = NULL;
 258
 259         if (sfd->vm_ops->get_policy)
 260                 pol = sfd->vm_ops->get_policy(vma, addr);
 261         else if (vma->vm_policy)
 262                 pol = vma->vm_policy;
 263         else
 264                 pol = current->mempolicy;
 265         return pol;
 266 }
 267 #endif
 268
 269 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
 270 {
 271         struct shm_file_data *sfd = shm_file_data(file);
 272         int ret;
 273
 274         ret = sfd->file->f_op->mmap(sfd->file, vma);
 275         if (ret != 0)
 276                 return ret;
 277         sfd->vm_ops = vma->vm_ops;
 278 #ifdef CONFIG_MMU
 279         BUG_ON(!sfd->vm_ops->fault);
 280 #endif
 281         vma->vm_ops = &shm_vm_ops;
 282         shm_open(vma);
 283
 284         return ret;
 285 }
 286
 287 static int shm_release(struct inode *ino, struct file *file)
 288 {
 289         struct shm_file_data *sfd = shm_file_data(file);
 290
 291         put_ipc_ns(sfd->ns);
 292         shm_file_data(file) = NULL;
 293         kfree(sfd);
 294         return 0;
 295 }
 296
 297 static int shm_fsync(struct file *file, struct dentry *dentry, int datasync)
 298 {
 299         int (*fsync) (struct file *, struct dentry *, int datasync);
 300         struct shm_file_data *sfd = shm_file_data(file);
 301         int ret = -EINVAL;
 302
 303         fsync = sfd->file->f_op->fsync;
 304         if (fsync)
 305                 ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync);
 306         return ret;
 307 }
 308
 309 static unsigned long shm_get_unmapped_area(struct file *file,
 310         unsigned long addr, unsigned long len, unsigned long pgoff,
 311         unsigned long flags)
 312 {
 313         struct shm_file_data *sfd = shm_file_data(file);
 314         return get_unmapped_area(sfd->file, addr, len, pgoff, flags);
 315 }
 316
 317 int is_file_shm_hugepages(struct file *file)
 318 {
 319         int ret = 0;
 320
 321         if (file->f_op == &shm_file_operations) {
 322                 struct shm_file_data *sfd;
 323                 sfd = shm_file_data(file);
 324                 ret = is_file_hugepages(sfd->file);
 325         }
 326         return ret;
 327 }
 328
 329 static const struct file_operations shm_file_operations = {
 330         .mmap           = shm_mmap,
 331         .fsync          = shm_fsync,
 332         .release        = shm_release,
 333         .get_unmapped_area      = shm_get_unmapped_area,
 334 };
 335
 336 static struct vm_operations_struct shm_vm_ops = {
 337         .open   = shm_open,     /* callback for a new vm-area open */
 338         .close  = shm_close,    /* callback for when the vm-area is released */
 339         .fault  = shm_fault,
 340 #if defined(CONFIG_NUMA)
 341         .set_policy = shm_set_policy,
 342         .get_policy = shm_get_policy,
 343 #endif
 344 };
 345
 346 static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
 347 {
 348         key_t key = params->key;
 349         int shmflg = params->flg;
 350         size_t size = params->u.size;
 351         int error;
 352         struct shmid_kernel *shp;
 353         int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
 354         struct file * file;
 355         char name[13];
 356         int id;
 357
 358         if (size < SHMMIN || size > ns->shm_ctlmax)
 359                 return -EINVAL;
 360
 361         if (ns->shm_tot + numpages > ns->shm_ctlall)
 362                 return -ENOSPC;
 363
 364         shp = ipc_rcu_alloc(sizeof(*shp));
 365         if (!shp)
 366                 return -ENOMEM;
 367
 368         shp->shm_perm.key = key;
 369         shp->shm_perm.mode = (shmflg & S_IRWXUGO);
 370         shp->mlock_user = NULL;
 371
 372         shp->shm_perm.security = NULL;
 373         error = security_shm_alloc(shp);
 374         if (error) {
 375                 ipc_rcu_putref(shp);
 376                 return error;
 377         }
 378
 379         sprintf (name, "SYSV%08x", key);
 380         if (shmflg & SHM_HUGETLB) {
 381                 /* hugetlb_file_setup takes care of mlock user accounting */
 382                 file = hugetlb_file_setup(name, size);
 383                 shp->mlock_user = current->user;
 384         } else {
 385                 int acctflag = VM_ACCOUNT;
 386                 /*
 387                  * Do not allow no accounting for OVERCOMMIT_NEVER, even
 388                  * if it's asked for.
 389                  */
 390                 if  ((shmflg & SHM_NORESERVE) &&
 391                                 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
 392                         acctflag = 0;
 393                 file = shmem_file_setup(name, size, acctflag);
 394         }
 395         error = PTR_ERR(file);
 396         if (IS_ERR(file))
 397                 goto no_file;
 398
 399         error = -ENOSPC;
 400         id = shm_addid(ns, shp);
 401         if(id == -1)
 402                 goto no_id;
 403
 404         shp->shm_cprid = task_tgid_vnr(current);
 405         shp->shm_lprid = 0;
 406         shp->shm_atim = shp->shm_dtim = 0;
 407         shp->shm_ctim = get_seconds();
 408         shp->shm_segsz = size;
 409         shp->shm_nattch = 0;
 410         shp->shm_perm.id = shm_buildid(ns, id, shp->shm_perm.seq);
 411         shp->shm_file = file;
 412         /*
 413          * shmid gets reported as "inode#" in /proc/pid/maps.
 414          * proc-ps tools use this. Changing this will break them.
 415          */
 416         file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
 417
 418         ns->shm_tot += numpages;
 419         error = shp->shm_perm.id;
 420         shm_unlock(shp);
 421         return error;
 422
 423 no_id:
 424         fput(file);
 425 no_file:
 426         security_shm_free(shp);
 427         ipc_rcu_putref(shp);
 428         return error;
 429 }
 430
 431 static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
 432 {
 433         struct shmid_kernel *shp;
 434
 435         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 436         return security_shm_associate(shp, shmflg);
 437 }
 438
 439 static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
 440                                 struct ipc_params *params)
 441 {
 442         struct shmid_kernel *shp;
 443
 444         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 445         if (shp->shm_segsz < params->u.size)
 446                 return -EINVAL;
 447
 448         return 0;
 449 }
 450
 451 asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
 452 {
 453         struct ipc_namespace *ns;
 454         struct ipc_ops shm_ops;
 455         struct ipc_params shm_params;
 456
 457         ns = current->nsproxy->ipc_ns;
 458
 459         shm_ops.getnew = newseg;
 460         shm_ops.associate = shm_security;
 461         shm_ops.more_checks = shm_more_checks;
 462
 463         shm_params.key = key;
 464         shm_params.flg = shmflg;
 465         shm_params.u.size = size;
 466
 467         return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
 468 }
 469
 470 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
 471 {
 472         switch(version) {
 473         case IPC_64:
 474                 return copy_to_user(buf, in, sizeof(*in));
 475         case IPC_OLD:
 476             {
 477                 struct shmid_ds out;
 478
 479                 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
 480                 out.shm_segsz   = in->shm_segsz;
 481                 out.shm_atime   = in->shm_atime;
 482                 out.shm_dtime   = in->shm_dtime;
 483                 out.shm_ctime   = in->shm_ctime;
 484                 out.shm_cpid    = in->shm_cpid;
 485                 out.shm_lpid    = in->shm_lpid;
 486                 out.shm_nattch  = in->shm_nattch;
 487
 488                 return copy_to_user(buf, &out, sizeof(out));
 489             }
 490         default:
 491                 return -EINVAL;
 492         }
 493 }
 494
 495 struct shm_setbuf {
 496         uid_t   uid;
 497         gid_t   gid;
 498         mode_t  mode;
 499 };
 500
 501 static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
 502 {
 503         switch(version) {
 504         case IPC_64:
 505             {
 506                 struct shmid64_ds tbuf;
 507
 508                 if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
 509                         return -EFAULT;
 510
 511                 out->uid        = tbuf.shm_perm.uid;
 512                 out->gid        = tbuf.shm_perm.gid;
 513                 out->mode       = tbuf.shm_perm.mode;
 514
 515                 return 0;
 516             }
 517         case IPC_OLD:
 518             {
 519                 struct shmid_ds tbuf_old;
 520
 521                 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
 522                         return -EFAULT;
 523
 524                 out->uid        = tbuf_old.shm_perm.uid;
 525                 out->gid        = tbuf_old.shm_perm.gid;
 526                 out->mode       = tbuf_old.shm_perm.mode;
 527
 528                 return 0;
 529             }
 530         default:
 531                 return -EINVAL;
 532         }
 533 }
 534
 535 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
 536 {
 537         switch(version) {
 538         case IPC_64:
 539                 return copy_to_user(buf, in, sizeof(*in));
 540         case IPC_OLD:
 541             {
 542                 struct shminfo out;
 543
 544                 if(in->shmmax > INT_MAX)
 545                         out.shmmax = INT_MAX;
 546                 else
 547                         out.shmmax = (int)in->shmmax;
 548
 549                 out.shmmin      = in->shmmin;
 550                 out.shmmni      = in->shmmni;
 551                 out.shmseg      = in->shmseg;
 552                 out.shmall      = in->shmall;
 553
 554                 return copy_to_user(buf, &out, sizeof(out));
 555             }
 556         default:
 557                 return -EINVAL;
 558         }
 559 }
 560
 561 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
 562                 unsigned long *swp)
 563 {
 564         int next_id;
 565         int total, in_use;
 566
 567         *rss = 0;
 568         *swp = 0;
 569
 570         in_use = shm_ids(ns).in_use;
 571
 572         for (total = 0, next_id = 0; total < in_use; next_id++) {
 573                 struct shmid_kernel *shp;
 574                 struct inode *inode;
 575
 576                 /*
 577                  * idr_find() is called via shm_get(), so with shm_ids.mutex
 578                  * locked. Since ipc_addid() is also called with
 579                  * shm_ids.mutex down, there is no need to add read barriers
 580                  * here to gurantee the writes in ipc_addid() are seen in
 581                  * order here (for Alpha).
 582                  * However idr_find() itself does not necessary require
 583                  * ipc_ids.mutex down. So if idr_find() is used by other
 584                  * places without ipc_ids.mutex down, then it needs read
 585                  * read memory barriers as ipc_lock() does.
 586                  */
 587
 588                 shp = idr_find(&shm_ids(ns).ipcs_idr, next_id);
 589                 if (shp == NULL)
 590                         continue;
 591
 592                 inode = shp->shm_file->f_path.dentry->d_inode;
 593
 594                 if (is_file_hugepages(shp->shm_file)) {
 595                         struct address_space *mapping = inode->i_mapping;
 596                         *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
 597                 } else {
 598                         struct shmem_inode_info *info = SHMEM_I(inode);
 599                         spin_lock(&info->lock);
 600                         *rss += inode->i_mapping->nrpages;
 601                         *swp += info->swapped;
 602                         spin_unlock(&info->lock);
 603                 }
 604
 605                 total++;
 606         }
 607 }
 608
 609 asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
 610 {
 611         struct shm_setbuf setbuf;
 612         struct shmid_kernel *shp;
 613         int err, version;
 614         struct ipc_namespace *ns;
 615
 616         if (cmd < 0 || shmid < 0) {
 617                 err = -EINVAL;
 618                 goto out;
 619         }
 620
 621         version = ipc_parse_version(&cmd);
 622         ns = current->nsproxy->ipc_ns;
 623
 624         switch (cmd) { /* replace with proc interface ? */
 625         case IPC_INFO:
 626         {
 627                 struct shminfo64 shminfo;
 628
 629                 err = security_shm_shmctl(NULL, cmd);
 630                 if (err)
 631                         return err;
 632
 633                 memset(&shminfo,0,sizeof(shminfo));
 634                 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
 635                 shminfo.shmmax = ns->shm_ctlmax;
 636                 shminfo.shmall = ns->shm_ctlall;
 637
 638                 shminfo.shmmin = SHMMIN;
 639                 if(copy_shminfo_to_user (buf, &shminfo, version))
 640                         return -EFAULT;
 641                 /* reading a integer is always atomic */
 642                 err = ipc_get_maxid(&shm_ids(ns));
 643                 if(err<0)
 644                         err = 0;
 645                 goto out;
 646         }
 647         case SHM_INFO:
 648         {
 649                 struct shm_info shm_info;
 650
 651                 err = security_shm_shmctl(NULL, cmd);
 652                 if (err)
 653                         return err;
 654
 655                 memset(&shm_info,0,sizeof(shm_info));
 656                 mutex_lock(&shm_ids(ns).mutex);
 657                 shm_info.used_ids = shm_ids(ns).in_use;
 658                 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
 659                 shm_info.shm_tot = ns->shm_tot;
 660                 shm_info.swap_attempts = 0;
 661                 shm_info.swap_successes = 0;
 662                 err = ipc_get_maxid(&shm_ids(ns));
 663                 mutex_unlock(&shm_ids(ns).mutex);
 664                 if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
 665                         err = -EFAULT;
 666                         goto out;
 667                 }
 668
 669                 err = err < 0 ? 0 : err;
 670                 goto out;
 671         }
 672         case SHM_STAT:
 673         case IPC_STAT:
 674         {
 675                 struct shmid64_ds tbuf;
 676                 int result;
 677
 678                 if (!buf) {
 679                         err = -EFAULT;
 680                         goto out;
 681                 }
 682
 683                 if (cmd == SHM_STAT) {
 684                         shp = shm_lock(ns, shmid);
 685                         if (IS_ERR(shp)) {
 686                                 err = PTR_ERR(shp);
 687                                 goto out;
 688                         }
 689                         result = shp->shm_perm.id;
 690                 } else {
 691                         shp = shm_lock_check(ns, shmid);
 692                         if (IS_ERR(shp)) {
 693                                 err = PTR_ERR(shp);
 694                                 goto out;
 695                         }
 696                         result = 0;
 697                 }
 698                 err=-EACCES;
 699                 if (ipcperms (&shp->shm_perm, S_IRUGO))
 700                         goto out_unlock;
 701                 err = security_shm_shmctl(shp, cmd);
 702                 if (err)
 703                         goto out_unlock;
 704                 memset(&tbuf, 0, sizeof(tbuf));
 705                 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
 706                 tbuf.shm_segsz  = shp->shm_segsz;
 707                 tbuf.shm_atime  = shp->shm_atim;
 708                 tbuf.shm_dtime  = shp->shm_dtim;
 709                 tbuf.shm_ctime  = shp->shm_ctim;
 710                 tbuf.shm_cpid   = shp->shm_cprid;
 711                 tbuf.shm_lpid   = shp->shm_lprid;
 712                 tbuf.shm_nattch = shp->shm_nattch;
 713                 shm_unlock(shp);
 714                 if(copy_shmid_to_user (buf, &tbuf, version))
 715                         err = -EFAULT;
 716                 else
 717                         err = result;
 718                 goto out;
 719         }
 720         case SHM_LOCK:
 721         case SHM_UNLOCK:
 722         {
 723                 shp = shm_lock_check(ns, shmid);
 724                 if (IS_ERR(shp)) {
 725                         err = PTR_ERR(shp);
 726                         goto out;
 727                 }
 728
 729                 err = audit_ipc_obj(&(shp->shm_perm));
 730                 if (err)
 731                         goto out_unlock;
 732
 733                 if (!capable(CAP_IPC_LOCK)) {
 734                         err = -EPERM;
 735                         if (current->euid != shp->shm_perm.uid &&
 736                             current->euid != shp->shm_perm.cuid)
 737                                 goto out_unlock;
 738                         if (cmd == SHM_LOCK &&
 739                             !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
 740                                 goto out_unlock;
 741                 }
 742
 743                 err = security_shm_shmctl(shp, cmd);
 744                 if (err)
 745                         goto out_unlock;
 746
 747                 if(cmd==SHM_LOCK) {
 748                         struct user_struct * user = current->user;
 749                         if (!is_file_hugepages(shp->shm_file)) {
 750                                 err = shmem_lock(shp->shm_file, 1, user);
 751                                 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
 752                                         shp->shm_perm.mode |= SHM_LOCKED;
 753                                         shp->mlock_user = user;
 754                                 }
 755                         }
 756                 } else if (!is_file_hugepages(shp->shm_file)) {
 757                         shmem_lock(shp->shm_file, 0, shp->mlock_user);
 758                         shp->shm_perm.mode &= ~SHM_LOCKED;
 759                         shp->mlock_user = NULL;
 760                 }
 761                 shm_unlock(shp);
 762                 goto out;
 763         }
 764         case IPC_RMID:
 765         {
 766                 /*
 767                  *      We cannot simply remove the file. The SVID states
 768                  *      that the block remains until the last person
 769                  *      detaches from it, then is deleted. A shmat() on
 770                  *      an RMID segment is legal in older Linux and if
 771                  *      we change it apps break...
 772                  *
 773                  *      Instead we set a destroyed flag, and then blow
 774                  *      the name away when the usage hits zero.
 775                  */
 776                 mutex_lock(&shm_ids(ns).mutex);
 777                 shp = shm_lock_check(ns, shmid);
 778                 if (IS_ERR(shp)) {
 779                         err = PTR_ERR(shp);
 780                         goto out_up;
 781                 }
 782
 783                 err = audit_ipc_obj(&(shp->shm_perm));
 784                 if (err)
 785                         goto out_unlock_up;
 786
 787                 if (current->euid != shp->shm_perm.uid &&
 788                     current->euid != shp->shm_perm.cuid &&
 789                     !capable(CAP_SYS_ADMIN)) {
 790                         err=-EPERM;
 791                         goto out_unlock_up;
 792                 }
 793
 794                 err = security_shm_shmctl(shp, cmd);
 795                 if (err)
 796                         goto out_unlock_up;
 797
 798                 do_shm_rmid(ns, shp);
 799                 mutex_unlock(&shm_ids(ns).mutex);
 800                 goto out;
 801         }
 802
 803         case IPC_SET:
 804         {
 805                 if (!buf) {
 806                         err = -EFAULT;
 807                         goto out;
 808                 }
 809
 810                 if (copy_shmid_from_user (&setbuf, buf, version)) {
 811                         err = -EFAULT;
 812                         goto out;
 813                 }
 814                 mutex_lock(&shm_ids(ns).mutex);
 815                 shp = shm_lock_check(ns, shmid);
 816                 if (IS_ERR(shp)) {
 817                         err = PTR_ERR(shp);
 818                         goto out_up;
 819                 }
 820                 err = audit_ipc_obj(&(shp->shm_perm));
 821                 if (err)
 822                         goto out_unlock_up;
 823                 err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode);
 824                 if (err)
 825                         goto out_unlock_up;
 826                 err=-EPERM;
 827                 if (current->euid != shp->shm_perm.uid &&
 828                     current->euid != shp->shm_perm.cuid &&
 829                     !capable(CAP_SYS_ADMIN)) {
 830                         goto out_unlock_up;
 831                 }
 832
 833                 err = security_shm_shmctl(shp, cmd);
 834                 if (err)
 835                         goto out_unlock_up;
 836
 837                 shp->shm_perm.uid = setbuf.uid;
 838                 shp->shm_perm.gid = setbuf.gid;
 839                 shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO)
 840                         | (setbuf.mode & S_IRWXUGO);
 841                 shp->shm_ctim = get_seconds();
 842                 break;
 843         }
 844
 845         default:
 846                 err = -EINVAL;
 847                 goto out;
 848         }
 849
 850         err = 0;
 851 out_unlock_up:
 852         shm_unlock(shp);
 853 out_up:
 854         mutex_unlock(&shm_ids(ns).mutex);
 855         goto out;
 856 out_unlock:
 857         shm_unlock(shp);
 858 out:
 859         return err;
 860 }
 861
 862 /*
 863  * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
 864  *
 865  * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
 866  * "raddr" thing points to kernel space, and there has to be a wrapper around
 867  * this.
 868  */
 869 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
 870 {
 871         struct shmid_kernel *shp;
 872         unsigned long addr;
 873         unsigned long size;
 874         struct file * file;
 875         int    err;
 876         unsigned long flags;
 877         unsigned long prot;
 878         int acc_mode;
 879         unsigned long user_addr;
 880         struct ipc_namespace *ns;
 881         struct shm_file_data *sfd;
 882         struct path path;
 883         mode_t f_mode;
 884
 885         err = -EINVAL;
 886         if (shmid < 0)
 887                 goto out;
 888         else if ((addr = (ulong)shmaddr)) {
 889                 if (addr & (SHMLBA-1)) {
 890                         if (shmflg & SHM_RND)
 891                                 addr &= ~(SHMLBA-1);       /* round down */
 892                         else
 893 #ifndef __ARCH_FORCE_SHMLBA
 894                                 if (addr & ~PAGE_MASK)
 895 #endif
 896                                         goto out;
 897                 }
 898                 flags = MAP_SHARED | MAP_FIXED;
 899         } else {
 900                 if ((shmflg & SHM_REMAP))
 901                         goto out;
 902
 903                 flags = MAP_SHARED;
 904         }
 905
 906         if (shmflg & SHM_RDONLY) {
 907                 prot = PROT_READ;
 908                 acc_mode = S_IRUGO;
 909                 f_mode = FMODE_READ;
 910         } else {
 911                 prot = PROT_READ | PROT_WRITE;
 912                 acc_mode = S_IRUGO | S_IWUGO;
 913                 f_mode = FMODE_READ | FMODE_WRITE;
 914         }
 915         if (shmflg & SHM_EXEC) {
 916                 prot |= PROT_EXEC;
 917                 acc_mode |= S_IXUGO;
 918         }
 919
 920         /*
 921          * We cannot rely on the fs check since SYSV IPC does have an
 922          * additional creator id...
 923          */
 924         ns = current->nsproxy->ipc_ns;
 925         shp = shm_lock_check(ns, shmid);
 926         if (IS_ERR(shp)) {
 927                 err = PTR_ERR(shp);
 928                 goto out;
 929         }
 930
 931         err = -EACCES;
 932         if (ipcperms(&shp->shm_perm, acc_mode))
 933                 goto out_unlock;
 934
 935         err = security_shm_shmat(shp, shmaddr, shmflg);
 936         if (err)
 937                 goto out_unlock;
 938
 939         path.dentry = dget(shp->shm_file->f_path.dentry);
 940         path.mnt    = shp->shm_file->f_path.mnt;
 941         shp->shm_nattch++;
 942         size = i_size_read(path.dentry->d_inode);
 943         shm_unlock(shp);
 944
 945         err = -ENOMEM;
 946         sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
 947         if (!sfd)
 948                 goto out_put_dentry;
 949
 950         err = -ENOMEM;
 951
 952         file = alloc_file(path.mnt, path.dentry, f_mode, &shm_file_operations);
 953         if (!file)
 954                 goto out_free;
 955
 956         file->private_data = sfd;
 957         file->f_mapping = shp->shm_file->f_mapping;
 958         sfd->id = shp->shm_perm.id;
 959         sfd->ns = get_ipc_ns(ns);
 960         sfd->file = shp->shm_file;
 961         sfd->vm_ops = NULL;
 962
 963         down_write(&current->mm->mmap_sem);
 964         if (addr && !(shmflg & SHM_REMAP)) {
 965                 err = -EINVAL;
 966                 if (find_vma_intersection(current->mm, addr, addr + size))
 967                         goto invalid;
 968                 /*
 969                  * If shm segment goes below stack, make sure there is some
 970                  * space left for the stack to grow (at least 4 pages).
 971                  */
 972                 if (addr < current->mm->start_stack &&
 973                     addr > current->mm->start_stack - size - PAGE_SIZE * 5)
 974                         goto invalid;
 975         }
 976
 977         user_addr = do_mmap (file, addr, size, prot, flags, 0);
 978         *raddr = user_addr;
 979         err = 0;
 980         if (IS_ERR_VALUE(user_addr))
 981                 err = (long)user_addr;
 982 invalid:
 983         up_write(&current->mm->mmap_sem);
 984
 985         fput(file);
 986
 987 out_nattch:
 988         mutex_lock(&shm_ids(ns).mutex);
 989         shp = shm_lock(ns, shmid);
 990         BUG_ON(IS_ERR(shp));
 991         shp->shm_nattch--;
 992         if(shp->shm_nattch == 0 &&
 993            shp->shm_perm.mode & SHM_DEST)
 994                 shm_destroy(ns, shp);
 995         else
 996                 shm_unlock(shp);
 997         mutex_unlock(&shm_ids(ns).mutex);
 998
 999 out:
1000         return err;
1001
1002 out_unlock:
1003         shm_unlock(shp);
1004         goto out;
1005
1006 out_free:
1007         kfree(sfd);
1008 out_put_dentry:
1009         dput(path.dentry);
1010         goto out_nattch;
1011 }
1012
1013 asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
1014 {
1015         unsigned long ret;
1016         long err;
1017
1018         err = do_shmat(shmid, shmaddr, shmflg, &ret);
1019         if (err)
1020                 return err;
1021         force_successful_syscall_return();
1022         return (long)ret;
1023 }
1024
1025 /*
1026  * detach and kill segment if marked destroyed.
1027  * The work is done in shm_close.
1028  */
1029 asmlinkage long sys_shmdt(char __user *shmaddr)
1030 {
1031         struct mm_struct *mm = current->mm;
1032         struct vm_area_struct *vma, *next;
1033         unsigned long addr = (unsigned long)shmaddr;
1034         loff_t size = 0;
1035         int retval = -EINVAL;
1036
1037         if (addr & ~PAGE_MASK)
1038                 return retval;
1039
1040         down_write(&mm->mmap_sem);
1041
1042         /*
1043          * This function tries to be smart and unmap shm segments that
1044          * were modified by partial mlock or munmap calls:
1045          * - It first determines the size of the shm segment that should be
1046          *   unmapped: It searches for a vma that is backed by shm and that
1047          *   started at address shmaddr. It records it's size and then unmaps
1048          *   it.
1049          * - Then it unmaps all shm vmas that started at shmaddr and that
1050          *   are within the initially determined size.
1051          * Errors from do_munmap are ignored: the function only fails if
1052          * it's called with invalid parameters or if it's called to unmap
1053          * a part of a vma. Both calls in this function are for full vmas,
1054          * the parameters are directly copied from the vma itself and always
1055          * valid - therefore do_munmap cannot fail. (famous last words?)
1056          */
1057         /*
1058          * If it had been mremap()'d, the starting address would not
1059          * match the usual checks anyway. So assume all vma's are
1060          * above the starting address given.
1061          */
1062         vma = find_vma(mm, addr);
1063
1064         while (vma) {
1065                 next = vma->vm_next;
1066
1067                 /*
1068                  * Check if the starting address would match, i.e. it's
1069                  * a fragment created by mprotect() and/or munmap(), or it
1070                  * otherwise it starts at this address with no hassles.
1071                  */
1072                 if ((vma->vm_ops == &shm_vm_ops) &&
1073                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1074
1075
1076                         size = vma->vm_file->f_path.dentry->d_inode->i_size;
1077                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1078                         /*
1079                          * We discovered the size of the shm segment, so
1080                          * break out of here and fall through to the next
1081                          * loop that uses the size information to stop
1082                          * searching for matching vma's.
1083                          */
1084                         retval = 0;
1085                         vma = next;
1086                         break;
1087                 }
1088                 vma = next;
1089         }
1090
1091         /*
1092          * We need look no further than the maximum address a fragment
1093          * could possibly have landed at. Also cast things to loff_t to
1094          * prevent overflows and make comparisions vs. equal-width types.
1095          */
1096         size = PAGE_ALIGN(size);
1097         while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1098                 next = vma->vm_next;
1099
1100                 /* finding a matching vma now does not alter retval */
1101                 if ((vma->vm_ops == &shm_vm_ops) &&
1102                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1103
1104                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1105                 vma = next;
1106         }
1107
1108         up_write(&mm->mmap_sem);
1109         return retval;
1110 }
1111
1112 #ifdef CONFIG_PROC_FS
1113 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1114 {
1115         struct shmid_kernel *shp = it;
1116         char *format;
1117
1118 #define SMALL_STRING "%10d %10d  %4o %10u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1119 #define BIG_STRING   "%10d %10d  %4o %21u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1120
1121         if (sizeof(size_t) <= sizeof(int))
1122                 format = SMALL_STRING;
1123         else
1124                 format = BIG_STRING;
1125         return seq_printf(s, format,
1126                           shp->shm_perm.key,
1127                           shp->shm_perm.id,
1128                           shp->shm_perm.mode,
1129                           shp->shm_segsz,
1130                           shp->shm_cprid,
1131                           shp->shm_lprid,
1132                           shp->shm_nattch,
1133                           shp->shm_perm.uid,
1134                           shp->shm_perm.gid,
1135                           shp->shm_perm.cuid,
1136                           shp->shm_perm.cgid,
1137                           shp->shm_atim,
1138                           shp->shm_dtim,
1139                           shp->shm_ctim);
1140 }
1141 #endif