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/rwsem.h>
  39 #include <linux/nsproxy.h>
  40 #include <linux/mount.h>
  41 #include <linux/ipc_namespace.h>
  42
  43 #include <asm/uaccess.h>
  44
  45 #include "util.h"
  46
  47 struct shm_file_data {
  48         int id;
  49         struct ipc_namespace *ns;
  50         struct file *file;
  51         const struct vm_operations_struct *vm_ops;
  52 };
  53
  54 #define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
  55
  56 static const struct file_operations shm_file_operations;
  57 static const struct vm_operations_struct shm_vm_ops;
  58
  59 #define shm_ids(ns)     ((ns)->ids[IPC_SHM_IDS])
  60
  61 #define shm_unlock(shp)                 \
  62         ipc_unlock(&(shp)->shm_perm)
  63
  64 static int newseg(struct ipc_namespace *, struct ipc_params *);
  65 static void shm_open(struct vm_area_struct *vma);
  66 static void shm_close(struct vm_area_struct *vma);
  67 static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
  68 #ifdef CONFIG_PROC_FS
  69 static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
  70 #endif
  71
  72 void shm_init_ns(struct ipc_namespace *ns)
  73 {
  74         ns->shm_ctlmax = SHMMAX;
  75         ns->shm_ctlall = SHMALL;
  76         ns->shm_ctlmni = SHMMNI;
  77         ns->shm_tot = 0;
  78         ipc_init_ids(&shm_ids(ns));
  79 }
  80
  81 /*
  82  * Called with shm_ids.rw_mutex (writer) and the shp structure locked.
  83  * Only shm_ids.rw_mutex remains locked on exit.
  84  */
  85 static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
  86 {
  87         struct shmid_kernel *shp;
  88         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
  89
  90         if (shp->shm_nattch){
  91                 shp->shm_perm.mode |= SHM_DEST;
  92                 /* Do not find it any more */
  93                 shp->shm_perm.key = IPC_PRIVATE;
  94                 shm_unlock(shp);
  95         } else
  96                 shm_destroy(ns, shp);
  97 }
  98
  99 #ifdef CONFIG_IPC_NS
 100 void shm_exit_ns(struct ipc_namespace *ns)
 101 {
 102         free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
 103         idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
 104 }
 105 #endif
 106
 107 void __init shm_init (void)
 108 {
 109         shm_init_ns(&init_ipc_ns);
 110         ipc_init_proc_interface("sysvipc/shm",
 111                                 "       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime\n",
 112                                 IPC_SHM_IDS, sysvipc_shm_proc_show);
 113 }
 114
 115 /*
 116  * shm_lock_(check_) routines are called in the paths where the rw_mutex
 117  * is not necessarily held.
 118  */
 119 static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
 120 {
 121         struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
 122
 123         if (IS_ERR(ipcp))
 124                 return (struct shmid_kernel *)ipcp;
 125
 126         return container_of(ipcp, struct shmid_kernel, shm_perm);
 127 }
 128
 129 static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
 130                                                 int id)
 131 {
 132         struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id);
 133
 134         if (IS_ERR(ipcp))
 135                 return (struct shmid_kernel *)ipcp;
 136
 137         return container_of(ipcp, struct shmid_kernel, shm_perm);
 138 }
 139
 140 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
 141 {
 142         ipc_rmid(&shm_ids(ns), &s->shm_perm);
 143 }
 144
 145
 146 /* This is called by fork, once for every shm attach. */
 147 static void shm_open(struct vm_area_struct *vma)
 148 {
 149         struct file *file = vma->vm_file;
 150         struct shm_file_data *sfd = shm_file_data(file);
 151         struct shmid_kernel *shp;
 152
 153         shp = shm_lock(sfd->ns, sfd->id);
 154         BUG_ON(IS_ERR(shp));
 155         shp->shm_atim = get_seconds();
 156         shp->shm_lprid = task_tgid_vnr(current);
 157         shp->shm_nattch++;
 158         shm_unlock(shp);
 159 }
 160
 161 /*
 162  * shm_destroy - free the struct shmid_kernel
 163  *
 164  * @ns: namespace
 165  * @shp: struct to free
 166  *
 167  * It has to be called with shp and shm_ids.rw_mutex (writer) locked,
 168  * but returns with shp unlocked and freed.
 169  */
 170 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
 171 {
 172         ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
 173         shm_rmid(ns, shp);
 174         shm_unlock(shp);
 175         if (!is_file_hugepages(shp->shm_file))
 176                 shmem_lock(shp->shm_file, 0, shp->mlock_user);
 177         else if (shp->mlock_user)
 178                 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
 179                                                 shp->mlock_user);
 180         fput (shp->shm_file);
 181         security_shm_free(shp);
 182         ipc_rcu_putref(shp);
 183 }
 184
 185 /*
 186  * remove the attach descriptor vma.
 187  * free memory for segment if it is marked destroyed.
 188  * The descriptor has already been removed from the current->mm->mmap list
 189  * and will later be kfree()d.
 190  */
 191 static void shm_close(struct vm_area_struct *vma)
 192 {
 193         struct file * file = vma->vm_file;
 194         struct shm_file_data *sfd = shm_file_data(file);
 195         struct shmid_kernel *shp;
 196         struct ipc_namespace *ns = sfd->ns;
 197
 198         down_write(&shm_ids(ns).rw_mutex);
 199         /* remove from the list of attaches of the shm segment */
 200         shp = shm_lock(ns, sfd->id);
 201         BUG_ON(IS_ERR(shp));
 202         shp->shm_lprid = task_tgid_vnr(current);
 203         shp->shm_dtim = get_seconds();
 204         shp->shm_nattch--;
 205         if(shp->shm_nattch == 0 &&
 206            shp->shm_perm.mode & SHM_DEST)
 207                 shm_destroy(ns, shp);
 208         else
 209                 shm_unlock(shp);
 210         up_write(&shm_ids(ns).rw_mutex);
 211 }
 212
 213 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 214 {
 215         struct file *file = vma->vm_file;
 216         struct shm_file_data *sfd = shm_file_data(file);
 217
 218         return sfd->vm_ops->fault(vma, vmf);
 219 }
 220
 221 #ifdef CONFIG_NUMA
 222 static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
 223 {
 224         struct file *file = vma->vm_file;
 225         struct shm_file_data *sfd = shm_file_data(file);
 226         int err = 0;
 227         if (sfd->vm_ops->set_policy)
 228                 err = sfd->vm_ops->set_policy(vma, new);
 229         return err;
 230 }
 231
 232 static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
 233                                         unsigned long addr)
 234 {
 235         struct file *file = vma->vm_file;
 236         struct shm_file_data *sfd = shm_file_data(file);
 237         struct mempolicy *pol = NULL;
 238
 239         if (sfd->vm_ops->get_policy)
 240                 pol = sfd->vm_ops->get_policy(vma, addr);
 241         else if (vma->vm_policy)
 242                 pol = vma->vm_policy;
 243
 244         return pol;
 245 }
 246 #endif
 247
 248 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
 249 {
 250         struct shm_file_data *sfd = shm_file_data(file);
 251         int ret;
 252
 253         ret = sfd->file->f_op->mmap(sfd->file, vma);
 254         if (ret != 0)
 255                 return ret;
 256         sfd->vm_ops = vma->vm_ops;
 257 #ifdef CONFIG_MMU
 258         BUG_ON(!sfd->vm_ops->fault);
 259 #endif
 260         vma->vm_ops = &shm_vm_ops;
 261         shm_open(vma);
 262
 263         return ret;
 264 }
 265
 266 static int shm_release(struct inode *ino, struct file *file)
 267 {
 268         struct shm_file_data *sfd = shm_file_data(file);
 269
 270         put_ipc_ns(sfd->ns);
 271         shm_file_data(file) = NULL;
 272         kfree(sfd);
 273         return 0;
 274 }
 275
 276 static int shm_fsync(struct file *file, int datasync)
 277 {
 278         struct shm_file_data *sfd = shm_file_data(file);
 279
 280         if (!sfd->file->f_op->fsync)
 281                 return -EINVAL;
 282         return sfd->file->f_op->fsync(sfd->file, datasync);
 283 }
 284
 285 static unsigned long shm_get_unmapped_area(struct file *file,
 286         unsigned long addr, unsigned long len, unsigned long pgoff,
 287         unsigned long flags)
 288 {
 289         struct shm_file_data *sfd = shm_file_data(file);
 290         return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
 291                                                 pgoff, flags);
 292 }
 293
 294 static const struct file_operations shm_file_operations = {
 295         .mmap           = shm_mmap,
 296         .fsync          = shm_fsync,
 297         .release        = shm_release,
 298 #ifndef CONFIG_MMU
 299         .get_unmapped_area      = shm_get_unmapped_area,
 300 #endif
 301         .llseek         = noop_llseek,
 302 };
 303
 304 static const struct file_operations shm_file_operations_huge = {
 305         .mmap           = shm_mmap,
 306         .fsync          = shm_fsync,
 307         .release        = shm_release,
 308         .get_unmapped_area      = shm_get_unmapped_area,
 309         .llseek         = noop_llseek,
 310 };
 311
 312 int is_file_shm_hugepages(struct file *file)
 313 {
 314         return file->f_op == &shm_file_operations_huge;
 315 }
 316
 317 static const struct vm_operations_struct shm_vm_ops = {
 318         .open   = shm_open,     /* callback for a new vm-area open */
 319         .close  = shm_close,    /* callback for when the vm-area is released */
 320         .fault  = shm_fault,
 321 #if defined(CONFIG_NUMA)
 322         .set_policy = shm_set_policy,
 323         .get_policy = shm_get_policy,
 324 #endif
 325 };
 326
 327 /**
 328  * newseg - Create a new shared memory segment
 329  * @ns: namespace
 330  * @params: ptr to the structure that contains key, size and shmflg
 331  *
 332  * Called with shm_ids.rw_mutex held as a writer.
 333  */
 334
 335 static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
 336 {
 337         key_t key = params->key;
 338         int shmflg = params->flg;
 339         size_t size = params->u.size;
 340         int error;
 341         struct shmid_kernel *shp;
 342         int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
 343         struct file * file;
 344         char name[13];
 345         int id;
 346         int acctflag = 0;
 347
 348         if (size < SHMMIN || size > ns->shm_ctlmax)
 349                 return -EINVAL;
 350
 351         if (ns->shm_tot + numpages > ns->shm_ctlall)
 352                 return -ENOSPC;
 353
 354         shp = ipc_rcu_alloc(sizeof(*shp));
 355         if (!shp)
 356                 return -ENOMEM;
 357
 358         shp->shm_perm.key = key;
 359         shp->shm_perm.mode = (shmflg & S_IRWXUGO);
 360         shp->mlock_user = NULL;
 361
 362         shp->shm_perm.security = NULL;
 363         error = security_shm_alloc(shp);
 364         if (error) {
 365                 ipc_rcu_putref(shp);
 366                 return error;
 367         }
 368
 369         sprintf (name, "SYSV%08x", key);
 370         if (shmflg & SHM_HUGETLB) {
 371                 /* hugetlb_file_setup applies strict accounting */
 372                 if (shmflg & SHM_NORESERVE)
 373                         acctflag = VM_NORESERVE;
 374                 file = hugetlb_file_setup(name, size, acctflag,
 375                                         &shp->mlock_user, HUGETLB_SHMFS_INODE);
 376         } else {
 377                 /*
 378                  * Do not allow no accounting for OVERCOMMIT_NEVER, even
 379                  * if it's asked for.
 380                  */
 381                 if  ((shmflg & SHM_NORESERVE) &&
 382                                 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
 383                         acctflag = VM_NORESERVE;
 384                 file = shmem_file_setup(name, size, acctflag);
 385         }
 386         error = PTR_ERR(file);
 387         if (IS_ERR(file))
 388                 goto no_file;
 389
 390         id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
 391         if (id < 0) {
 392                 error = id;
 393                 goto no_id;
 394         }
 395
 396         shp->shm_cprid = task_tgid_vnr(current);
 397         shp->shm_lprid = 0;
 398         shp->shm_atim = shp->shm_dtim = 0;
 399         shp->shm_ctim = get_seconds();
 400         shp->shm_segsz = size;
 401         shp->shm_nattch = 0;
 402         shp->shm_file = file;
 403         /*
 404          * shmid gets reported as "inode#" in /proc/pid/maps.
 405          * proc-ps tools use this. Changing this will break them.
 406          */
 407         file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
 408
 409         ns->shm_tot += numpages;
 410         error = shp->shm_perm.id;
 411         shm_unlock(shp);
 412         return error;
 413
 414 no_id:
 415         if (is_file_hugepages(file) && shp->mlock_user)
 416                 user_shm_unlock(size, shp->mlock_user);
 417         fput(file);
 418 no_file:
 419         security_shm_free(shp);
 420         ipc_rcu_putref(shp);
 421         return error;
 422 }
 423
 424 /*
 425  * Called with shm_ids.rw_mutex and ipcp locked.
 426  */
 427 static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
 428 {
 429         struct shmid_kernel *shp;
 430
 431         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 432         return security_shm_associate(shp, shmflg);
 433 }
 434
 435 /*
 436  * Called with shm_ids.rw_mutex and ipcp locked.
 437  */
 438 static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
 439                                 struct ipc_params *params)
 440 {
 441         struct shmid_kernel *shp;
 442
 443         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 444         if (shp->shm_segsz < params->u.size)
 445                 return -EINVAL;
 446
 447         return 0;
 448 }
 449
 450 SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
 451 {
 452         struct ipc_namespace *ns;
 453         struct ipc_ops shm_ops;
 454         struct ipc_params shm_params;
 455
 456         ns = current->nsproxy->ipc_ns;
 457
 458         shm_ops.getnew = newseg;
 459         shm_ops.associate = shm_security;
 460         shm_ops.more_checks = shm_more_checks;
 461
 462         shm_params.key = key;
 463         shm_params.flg = shmflg;
 464         shm_params.u.size = size;
 465
 466         return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
 467 }
 468
 469 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
 470 {
 471         switch(version) {
 472         case IPC_64:
 473                 return copy_to_user(buf, in, sizeof(*in));
 474         case IPC_OLD:
 475             {
 476                 struct shmid_ds out;
 477
 478                 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
 479                 out.shm_segsz   = in->shm_segsz;
 480                 out.shm_atime   = in->shm_atime;
 481                 out.shm_dtime   = in->shm_dtime;
 482                 out.shm_ctime   = in->shm_ctime;
 483                 out.shm_cpid    = in->shm_cpid;
 484                 out.shm_lpid    = in->shm_lpid;
 485                 out.shm_nattch  = in->shm_nattch;
 486
 487                 return copy_to_user(buf, &out, sizeof(out));
 488             }
 489         default:
 490                 return -EINVAL;
 491         }
 492 }
 493
 494 static inline unsigned long
 495 copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
 496 {
 497         switch(version) {
 498         case IPC_64:
 499                 if (copy_from_user(out, buf, sizeof(*out)))
 500                         return -EFAULT;
 501                 return 0;
 502         case IPC_OLD:
 503             {
 504                 struct shmid_ds tbuf_old;
 505
 506                 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
 507                         return -EFAULT;
 508
 509                 out->shm_perm.uid       = tbuf_old.shm_perm.uid;
 510                 out->shm_perm.gid       = tbuf_old.shm_perm.gid;
 511                 out->shm_perm.mode      = tbuf_old.shm_perm.mode;
 512
 513                 return 0;
 514             }
 515         default:
 516                 return -EINVAL;
 517         }
 518 }
 519
 520 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
 521 {
 522         switch(version) {
 523         case IPC_64:
 524                 return copy_to_user(buf, in, sizeof(*in));
 525         case IPC_OLD:
 526             {
 527                 struct shminfo out;
 528
 529                 if(in->shmmax > INT_MAX)
 530                         out.shmmax = INT_MAX;
 531                 else
 532                         out.shmmax = (int)in->shmmax;
 533
 534                 out.shmmin      = in->shmmin;
 535                 out.shmmni      = in->shmmni;
 536                 out.shmseg      = in->shmseg;
 537                 out.shmall      = in->shmall;
 538
 539                 return copy_to_user(buf, &out, sizeof(out));
 540             }
 541         default:
 542                 return -EINVAL;
 543         }
 544 }
 545
 546 /*
 547  * Called with shm_ids.rw_mutex held as a reader
 548  */
 549 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
 550                 unsigned long *swp)
 551 {
 552         int next_id;
 553         int total, in_use;
 554
 555         *rss = 0;
 556         *swp = 0;
 557
 558         in_use = shm_ids(ns).in_use;
 559
 560         for (total = 0, next_id = 0; total < in_use; next_id++) {
 561                 struct kern_ipc_perm *ipc;
 562                 struct shmid_kernel *shp;
 563                 struct inode *inode;
 564
 565                 ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
 566                 if (ipc == NULL)
 567                         continue;
 568                 shp = container_of(ipc, struct shmid_kernel, shm_perm);
 569
 570                 inode = shp->shm_file->f_path.dentry->d_inode;
 571
 572                 if (is_file_hugepages(shp->shm_file)) {
 573                         struct address_space *mapping = inode->i_mapping;
 574                         struct hstate *h = hstate_file(shp->shm_file);
 575                         *rss += pages_per_huge_page(h) * mapping->nrpages;
 576                 } else {
 577 #ifdef CONFIG_SHMEM
 578                         struct shmem_inode_info *info = SHMEM_I(inode);
 579                         spin_lock(&info->lock);
 580                         *rss += inode->i_mapping->nrpages;
 581                         *swp += info->swapped;
 582                         spin_unlock(&info->lock);
 583 #else
 584                         *rss += inode->i_mapping->nrpages;
 585 #endif
 586                 }
 587
 588                 total++;
 589         }
 590 }
 591
 592 /*
 593  * This function handles some shmctl commands which require the rw_mutex
 594  * to be held in write mode.
 595  * NOTE: no locks must be held, the rw_mutex is taken inside this function.
 596  */
 597 static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
 598                        struct shmid_ds __user *buf, int version)
 599 {
 600         struct kern_ipc_perm *ipcp;
 601         struct shmid64_ds shmid64;
 602         struct shmid_kernel *shp;
 603         int err;
 604
 605         if (cmd == IPC_SET) {
 606                 if (copy_shmid_from_user(&shmid64, buf, version))
 607                         return -EFAULT;
 608         }
 609
 610         ipcp = ipcctl_pre_down(&shm_ids(ns), shmid, cmd, &shmid64.shm_perm, 0);
 611         if (IS_ERR(ipcp))
 612                 return PTR_ERR(ipcp);
 613
 614         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 615
 616         err = security_shm_shmctl(shp, cmd);
 617         if (err)
 618                 goto out_unlock;
 619         switch (cmd) {
 620         case IPC_RMID:
 621                 do_shm_rmid(ns, ipcp);
 622                 goto out_up;
 623         case IPC_SET:
 624                 ipc_update_perm(&shmid64.shm_perm, ipcp);
 625                 shp->shm_ctim = get_seconds();
 626                 break;
 627         default:
 628                 err = -EINVAL;
 629         }
 630 out_unlock:
 631         shm_unlock(shp);
 632 out_up:
 633         up_write(&shm_ids(ns).rw_mutex);
 634         return err;
 635 }
 636
 637 SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
 638 {
 639         struct shmid_kernel *shp;
 640         int err, version;
 641         struct ipc_namespace *ns;
 642
 643         if (cmd < 0 || shmid < 0) {
 644                 err = -EINVAL;
 645                 goto out;
 646         }
 647
 648         version = ipc_parse_version(&cmd);
 649         ns = current->nsproxy->ipc_ns;
 650
 651         switch (cmd) { /* replace with proc interface ? */
 652         case IPC_INFO:
 653         {
 654                 struct shminfo64 shminfo;
 655
 656                 err = security_shm_shmctl(NULL, cmd);
 657                 if (err)
 658                         return err;
 659
 660                 memset(&shminfo, 0, sizeof(shminfo));
 661                 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
 662                 shminfo.shmmax = ns->shm_ctlmax;
 663                 shminfo.shmall = ns->shm_ctlall;
 664
 665                 shminfo.shmmin = SHMMIN;
 666                 if(copy_shminfo_to_user (buf, &shminfo, version))
 667                         return -EFAULT;
 668
 669                 down_read(&shm_ids(ns).rw_mutex);
 670                 err = ipc_get_maxid(&shm_ids(ns));
 671                 up_read(&shm_ids(ns).rw_mutex);
 672
 673                 if(err<0)
 674                         err = 0;
 675                 goto out;
 676         }
 677         case SHM_INFO:
 678         {
 679                 struct shm_info shm_info;
 680
 681                 err = security_shm_shmctl(NULL, cmd);
 682                 if (err)
 683                         return err;
 684
 685                 memset(&shm_info, 0, sizeof(shm_info));
 686                 down_read(&shm_ids(ns).rw_mutex);
 687                 shm_info.used_ids = shm_ids(ns).in_use;
 688                 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
 689                 shm_info.shm_tot = ns->shm_tot;
 690                 shm_info.swap_attempts = 0;
 691                 shm_info.swap_successes = 0;
 692                 err = ipc_get_maxid(&shm_ids(ns));
 693                 up_read(&shm_ids(ns).rw_mutex);
 694                 if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {
 695                         err = -EFAULT;
 696                         goto out;
 697                 }
 698
 699                 err = err < 0 ? 0 : err;
 700                 goto out;
 701         }
 702         case SHM_STAT:
 703         case IPC_STAT:
 704         {
 705                 struct shmid64_ds tbuf;
 706                 int result;
 707
 708                 if (cmd == SHM_STAT) {
 709                         shp = shm_lock(ns, shmid);
 710                         if (IS_ERR(shp)) {
 711                                 err = PTR_ERR(shp);
 712                                 goto out;
 713                         }
 714                         result = shp->shm_perm.id;
 715                 } else {
 716                         shp = shm_lock_check(ns, shmid);
 717                         if (IS_ERR(shp)) {
 718                                 err = PTR_ERR(shp);
 719                                 goto out;
 720                         }
 721                         result = 0;
 722                 }
 723                 err = -EACCES;
 724                 if (ipcperms (&shp->shm_perm, S_IRUGO))
 725                         goto out_unlock;
 726                 err = security_shm_shmctl(shp, cmd);
 727                 if (err)
 728                         goto out_unlock;
 729                 memset(&tbuf, 0, sizeof(tbuf));
 730                 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
 731                 tbuf.shm_segsz  = shp->shm_segsz;
 732                 tbuf.shm_atime  = shp->shm_atim;
 733                 tbuf.shm_dtime  = shp->shm_dtim;
 734                 tbuf.shm_ctime  = shp->shm_ctim;
 735                 tbuf.shm_cpid   = shp->shm_cprid;
 736                 tbuf.shm_lpid   = shp->shm_lprid;
 737                 tbuf.shm_nattch = shp->shm_nattch;
 738                 shm_unlock(shp);
 739                 if(copy_shmid_to_user (buf, &tbuf, version))
 740                         err = -EFAULT;
 741                 else
 742                         err = result;
 743                 goto out;
 744         }
 745         case SHM_LOCK:
 746         case SHM_UNLOCK:
 747         {
 748                 struct file *uninitialized_var(shm_file);
 749
 750                 lru_add_drain_all();  /* drain pagevecs to lru lists */
 751
 752                 shp = shm_lock_check(ns, shmid);
 753                 if (IS_ERR(shp)) {
 754                         err = PTR_ERR(shp);
 755                         goto out;
 756                 }
 757
 758                 audit_ipc_obj(&(shp->shm_perm));
 759
 760                 if (!capable(CAP_IPC_LOCK)) {
 761                         uid_t euid = current_euid();
 762                         err = -EPERM;
 763                         if (euid != shp->shm_perm.uid &&
 764                             euid != shp->shm_perm.cuid)
 765                                 goto out_unlock;
 766                         if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK))
 767                                 goto out_unlock;
 768                 }
 769
 770                 err = security_shm_shmctl(shp, cmd);
 771                 if (err)
 772                         goto out_unlock;
 773
 774                 if(cmd==SHM_LOCK) {
 775                         struct user_struct *user = current_user();
 776                         if (!is_file_hugepages(shp->shm_file)) {
 777                                 err = shmem_lock(shp->shm_file, 1, user);
 778                                 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
 779                                         shp->shm_perm.mode |= SHM_LOCKED;
 780                                         shp->mlock_user = user;
 781                                 }
 782                         }
 783                 } else if (!is_file_hugepages(shp->shm_file)) {
 784                         shmem_lock(shp->shm_file, 0, shp->mlock_user);
 785                         shp->shm_perm.mode &= ~SHM_LOCKED;
 786                         shp->mlock_user = NULL;
 787                 }
 788                 shm_unlock(shp);
 789                 goto out;
 790         }
 791         case IPC_RMID:
 792         case IPC_SET:
 793                 err = shmctl_down(ns, shmid, cmd, buf, version);
 794                 return err;
 795         default:
 796                 return -EINVAL;
 797         }
 798
 799 out_unlock:
 800         shm_unlock(shp);
 801 out:
 802         return err;
 803 }
 804
 805 /*
 806  * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
 807  *
 808  * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
 809  * "raddr" thing points to kernel space, and there has to be a wrapper around
 810  * this.
 811  */
 812 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
 813 {
 814         struct shmid_kernel *shp;
 815         unsigned long addr;
 816         unsigned long size;
 817         struct file * file;
 818         int    err;
 819         unsigned long flags;
 820         unsigned long prot;
 821         int acc_mode;
 822         unsigned long user_addr;
 823         struct ipc_namespace *ns;
 824         struct shm_file_data *sfd;
 825         struct path path;
 826         fmode_t f_mode;
 827
 828         err = -EINVAL;
 829         if (shmid < 0)
 830                 goto out;
 831         else if ((addr = (ulong)shmaddr)) {
 832                 if (addr & (SHMLBA-1)) {
 833                         if (shmflg & SHM_RND)
 834                                 addr &= ~(SHMLBA-1);       /* round down */
 835                         else
 836 #ifndef __ARCH_FORCE_SHMLBA
 837                                 if (addr & ~PAGE_MASK)
 838 #endif
 839                                         goto out;
 840                 }
 841                 flags = MAP_SHARED | MAP_FIXED;
 842         } else {
 843                 if ((shmflg & SHM_REMAP))
 844                         goto out;
 845
 846                 flags = MAP_SHARED;
 847         }
 848
 849         if (shmflg & SHM_RDONLY) {
 850                 prot = PROT_READ;
 851                 acc_mode = S_IRUGO;
 852                 f_mode = FMODE_READ;
 853         } else {
 854                 prot = PROT_READ | PROT_WRITE;
 855                 acc_mode = S_IRUGO | S_IWUGO;
 856                 f_mode = FMODE_READ | FMODE_WRITE;
 857         }
 858         if (shmflg & SHM_EXEC) {
 859                 prot |= PROT_EXEC;
 860                 acc_mode |= S_IXUGO;
 861         }
 862
 863         /*
 864          * We cannot rely on the fs check since SYSV IPC does have an
 865          * additional creator id...
 866          */
 867         ns = current->nsproxy->ipc_ns;
 868         shp = shm_lock_check(ns, shmid);
 869         if (IS_ERR(shp)) {
 870                 err = PTR_ERR(shp);
 871                 goto out;
 872         }
 873
 874         err = -EACCES;
 875         if (ipcperms(&shp->shm_perm, acc_mode))
 876                 goto out_unlock;
 877
 878         err = security_shm_shmat(shp, shmaddr, shmflg);
 879         if (err)
 880                 goto out_unlock;
 881
 882         path = shp->shm_file->f_path;
 883         path_get(&path);
 884         shp->shm_nattch++;
 885         size = i_size_read(path.dentry->d_inode);
 886         shm_unlock(shp);
 887
 888         err = -ENOMEM;
 889         sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
 890         if (!sfd)
 891                 goto out_put_dentry;
 892
 893         file = alloc_file(&path, f_mode,
 894                           is_file_hugepages(shp->shm_file) ?
 895                                 &shm_file_operations_huge :
 896                                 &shm_file_operations);
 897         if (!file)
 898                 goto out_free;
 899
 900         file->private_data = sfd;
 901         file->f_mapping = shp->shm_file->f_mapping;
 902         sfd->id = shp->shm_perm.id;
 903         sfd->ns = get_ipc_ns(ns);
 904         sfd->file = shp->shm_file;
 905         sfd->vm_ops = NULL;
 906
 907         down_write(&current->mm->mmap_sem);
 908         if (addr && !(shmflg & SHM_REMAP)) {
 909                 err = -EINVAL;
 910                 if (find_vma_intersection(current->mm, addr, addr + size))
 911                         goto invalid;
 912                 /*
 913                  * If shm segment goes below stack, make sure there is some
 914                  * space left for the stack to grow (at least 4 pages).
 915                  */
 916                 if (addr < current->mm->start_stack &&
 917                     addr > current->mm->start_stack - size - PAGE_SIZE * 5)
 918                         goto invalid;
 919         }
 920
 921         user_addr = do_mmap (file, addr, size, prot, flags, 0);
 922         *raddr = user_addr;
 923         err = 0;
 924         if (IS_ERR_VALUE(user_addr))
 925                 err = (long)user_addr;
 926 invalid:
 927         up_write(&current->mm->mmap_sem);
 928
 929         fput(file);
 930
 931 out_nattch:
 932         down_write(&shm_ids(ns).rw_mutex);
 933         shp = shm_lock(ns, shmid);
 934         BUG_ON(IS_ERR(shp));
 935         shp->shm_nattch--;
 936         if(shp->shm_nattch == 0 &&
 937            shp->shm_perm.mode & SHM_DEST)
 938                 shm_destroy(ns, shp);
 939         else
 940                 shm_unlock(shp);
 941         up_write(&shm_ids(ns).rw_mutex);
 942
 943 out:
 944         return err;
 945
 946 out_unlock:
 947         shm_unlock(shp);
 948         goto out;
 949
 950 out_free:
 951         kfree(sfd);
 952 out_put_dentry:
 953         path_put(&path);
 954         goto out_nattch;
 955 }
 956
 957 SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
 958 {
 959         unsigned long ret;
 960         long err;
 961
 962         err = do_shmat(shmid, shmaddr, shmflg, &ret);
 963         if (err)
 964                 return err;
 965         force_successful_syscall_return();
 966         return (long)ret;
 967 }
 968
 969 /*
 970  * detach and kill segment if marked destroyed.
 971  * The work is done in shm_close.
 972  */
 973 SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
 974 {
 975         struct mm_struct *mm = current->mm;
 976         struct vm_area_struct *vma;
 977         unsigned long addr = (unsigned long)shmaddr;
 978         int retval = -EINVAL;
 979 #ifdef CONFIG_MMU
 980         loff_t size = 0;
 981         struct vm_area_struct *next;
 982 #endif
 983
 984         if (addr & ~PAGE_MASK)
 985                 return retval;
 986
 987         down_write(&mm->mmap_sem);
 988
 989         /*
 990          * This function tries to be smart and unmap shm segments that
 991          * were modified by partial mlock or munmap calls:
 992          * - It first determines the size of the shm segment that should be
 993          *   unmapped: It searches for a vma that is backed by shm and that
 994          *   started at address shmaddr. It records it's size and then unmaps
 995          *   it.
 996          * - Then it unmaps all shm vmas that started at shmaddr and that
 997          *   are within the initially determined size.
 998          * Errors from do_munmap are ignored: the function only fails if
 999          * it's called with invalid parameters or if it's called to unmap
1000          * a part of a vma. Both calls in this function are for full vmas,
1001          * the parameters are directly copied from the vma itself and always
1002          * valid - therefore do_munmap cannot fail. (famous last words?)
1003          */
1004         /*
1005          * If it had been mremap()'d, the starting address would not
1006          * match the usual checks anyway. So assume all vma's are
1007          * above the starting address given.
1008          */
1009         vma = find_vma(mm, addr);
1010
1011 #ifdef CONFIG_MMU
1012         while (vma) {
1013                 next = vma->vm_next;
1014
1015                 /*
1016                  * Check if the starting address would match, i.e. it's
1017                  * a fragment created by mprotect() and/or munmap(), or it
1018                  * otherwise it starts at this address with no hassles.
1019                  */
1020                 if ((vma->vm_ops == &shm_vm_ops) &&
1021                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1022
1023
1024                         size = vma->vm_file->f_path.dentry->d_inode->i_size;
1025                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1026                         /*
1027                          * We discovered the size of the shm segment, so
1028                          * break out of here and fall through to the next
1029                          * loop that uses the size information to stop
1030                          * searching for matching vma's.
1031                          */
1032                         retval = 0;
1033                         vma = next;
1034                         break;
1035                 }
1036                 vma = next;
1037         }
1038
1039         /*
1040          * We need look no further than the maximum address a fragment
1041          * could possibly have landed at. Also cast things to loff_t to
1042          * prevent overflows and make comparisions vs. equal-width types.
1043          */
1044         size = PAGE_ALIGN(size);
1045         while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1046                 next = vma->vm_next;
1047
1048                 /* finding a matching vma now does not alter retval */
1049                 if ((vma->vm_ops == &shm_vm_ops) &&
1050                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1051
1052                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1053                 vma = next;
1054         }
1055
1056 #else /* CONFIG_MMU */
1057         /* under NOMMU conditions, the exact address to be destroyed must be
1058          * given */
1059         retval = -EINVAL;
1060         if (vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
1061                 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1062                 retval = 0;
1063         }
1064
1065 #endif
1066
1067         up_write(&mm->mmap_sem);
1068         return retval;
1069 }
1070
1071 #ifdef CONFIG_PROC_FS
1072 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1073 {
1074         struct shmid_kernel *shp = it;
1075
1076 #if BITS_PER_LONG <= 32
1077 #define SIZE_SPEC "%10lu"
1078 #else
1079 #define SIZE_SPEC "%21lu"
1080 #endif
1081
1082         return seq_printf(s,
1083                           "%10d %10d  %4o " SIZE_SPEC " %5u %5u  "
1084                           "%5lu %5u %5u %5u %5u %10lu %10lu %10lu\n",
1085                           shp->shm_perm.key,
1086                           shp->shm_perm.id,
1087                           shp->shm_perm.mode,
1088                           shp->shm_segsz,
1089                           shp->shm_cprid,
1090                           shp->shm_lprid,
1091                           shp->shm_nattch,
1092                           shp->shm_perm.uid,
1093                           shp->shm_perm.gid,
1094                           shp->shm_perm.cuid,
1095                           shp->shm_perm.cgid,
1096                           shp->shm_atim,
1097                           shp->shm_dtim,
1098                           shp->shm_ctim);
1099 }
1100 #endif