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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/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 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 #define shm_buildid(id, seq)    ipc_buildid(id, seq)
  64
  65 static int newseg(struct ipc_namespace *, struct ipc_params *);
  66 static void shm_open(struct vm_area_struct *vma);
  67 static void shm_close(struct vm_area_struct *vma);
  68 static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
  69 #ifdef CONFIG_PROC_FS
  70 static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
  71 #endif
  72
  73 void shm_init_ns(struct ipc_namespace *ns)
  74 {
  75         ns->shm_ctlmax = SHMMAX;
  76         ns->shm_ctlall = SHMALL;
  77         ns->shm_ctlmni = SHMMNI;
  78         ns->shm_tot = 0;
  79         ipc_init_ids(&ns->ids[IPC_SHM_IDS]);
  80 }
  81
  82 /*
  83  * Called with shm_ids.rw_mutex (writer) and the shp structure locked.
  84  * Only shm_ids.rw_mutex remains locked on exit.
  85  */
  86 static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
  87 {
  88         struct shmid_kernel *shp;
  89         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
  90
  91         if (shp->shm_nattch){
  92                 shp->shm_perm.mode |= SHM_DEST;
  93                 /* Do not find it any more */
  94                 shp->shm_perm.key = IPC_PRIVATE;
  95                 shm_unlock(shp);
  96         } else
  97                 shm_destroy(ns, shp);
  98 }
  99
 100 #ifdef CONFIG_IPC_NS
 101 void shm_exit_ns(struct ipc_namespace *ns)
 102 {
 103         free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
 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_)down routines are called in the paths where the rw_mutex
 117  * is held to protect access to the idr tree.
 118  */
 119 static inline struct shmid_kernel *shm_lock_down(struct ipc_namespace *ns,
 120                                                 int id)
 121 {
 122         struct kern_ipc_perm *ipcp = ipc_lock_down(&shm_ids(ns), id);
 123
 124         if (IS_ERR(ipcp))
 125                 return (struct shmid_kernel *)ipcp;
 126
 127         return container_of(ipcp, struct shmid_kernel, shm_perm);
 128 }
 129
 130 static inline struct shmid_kernel *shm_lock_check_down(
 131                                                 struct ipc_namespace *ns,
 132                                                 int id)
 133 {
 134         struct kern_ipc_perm *ipcp = ipc_lock_check_down(&shm_ids(ns), id);
 135
 136         if (IS_ERR(ipcp))
 137                 return (struct shmid_kernel *)ipcp;
 138
 139         return container_of(ipcp, struct shmid_kernel, shm_perm);
 140 }
 141
 142 /*
 143  * shm_lock_(check_) routines are called in the paths where the rw_mutex
 144  * is not held.
 145  */
 146 static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
 147 {
 148         struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
 149
 150         if (IS_ERR(ipcp))
 151                 return (struct shmid_kernel *)ipcp;
 152
 153         return container_of(ipcp, struct shmid_kernel, shm_perm);
 154 }
 155
 156 static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
 157                                                 int id)
 158 {
 159         struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id);
 160
 161         if (IS_ERR(ipcp))
 162                 return (struct shmid_kernel *)ipcp;
 163
 164         return container_of(ipcp, struct shmid_kernel, shm_perm);
 165 }
 166
 167 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
 168 {
 169         ipc_rmid(&shm_ids(ns), &s->shm_perm);
 170 }
 171
 172 static inline int shm_addid(struct ipc_namespace *ns, struct shmid_kernel *shp)
 173 {
 174         return ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
 175 }
 176
 177
 178
 179 /* This is called by fork, once for every shm attach. */
 180 static void shm_open(struct vm_area_struct *vma)
 181 {
 182         struct file *file = vma->vm_file;
 183         struct shm_file_data *sfd = shm_file_data(file);
 184         struct shmid_kernel *shp;
 185
 186         shp = shm_lock(sfd->ns, sfd->id);
 187         BUG_ON(IS_ERR(shp));
 188         shp->shm_atim = get_seconds();
 189         shp->shm_lprid = task_tgid_vnr(current);
 190         shp->shm_nattch++;
 191         shm_unlock(shp);
 192 }
 193
 194 /*
 195  * shm_destroy - free the struct shmid_kernel
 196  *
 197  * @ns: namespace
 198  * @shp: struct to free
 199  *
 200  * It has to be called with shp and shm_ids.rw_mutex (writer) locked,
 201  * but returns with shp unlocked and freed.
 202  */
 203 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
 204 {
 205         ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
 206         shm_rmid(ns, shp);
 207         shm_unlock(shp);
 208         if (!is_file_hugepages(shp->shm_file))
 209                 shmem_lock(shp->shm_file, 0, shp->mlock_user);
 210         else
 211                 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
 212                                                 shp->mlock_user);
 213         fput (shp->shm_file);
 214         security_shm_free(shp);
 215         ipc_rcu_putref(shp);
 216 }
 217
 218 /*
 219  * remove the attach descriptor vma.
 220  * free memory for segment if it is marked destroyed.
 221  * The descriptor has already been removed from the current->mm->mmap list
 222  * and will later be kfree()d.
 223  */
 224 static void shm_close(struct vm_area_struct *vma)
 225 {
 226         struct file * file = vma->vm_file;
 227         struct shm_file_data *sfd = shm_file_data(file);
 228         struct shmid_kernel *shp;
 229         struct ipc_namespace *ns = sfd->ns;
 230
 231         down_write(&shm_ids(ns).rw_mutex);
 232         /* remove from the list of attaches of the shm segment */
 233         shp = shm_lock_down(ns, sfd->id);
 234         BUG_ON(IS_ERR(shp));
 235         shp->shm_lprid = task_tgid_vnr(current);
 236         shp->shm_dtim = get_seconds();
 237         shp->shm_nattch--;
 238         if(shp->shm_nattch == 0 &&
 239            shp->shm_perm.mode & SHM_DEST)
 240                 shm_destroy(ns, shp);
 241         else
 242                 shm_unlock(shp);
 243         up_write(&shm_ids(ns).rw_mutex);
 244 }
 245
 246 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 247 {
 248         struct file *file = vma->vm_file;
 249         struct shm_file_data *sfd = shm_file_data(file);
 250
 251         return sfd->vm_ops->fault(vma, vmf);
 252 }
 253
 254 #ifdef CONFIG_NUMA
 255 static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
 256 {
 257         struct file *file = vma->vm_file;
 258         struct shm_file_data *sfd = shm_file_data(file);
 259         int err = 0;
 260         if (sfd->vm_ops->set_policy)
 261                 err = sfd->vm_ops->set_policy(vma, new);
 262         return err;
 263 }
 264
 265 static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
 266                                         unsigned long addr)
 267 {
 268         struct file *file = vma->vm_file;
 269         struct shm_file_data *sfd = shm_file_data(file);
 270         struct mempolicy *pol = NULL;
 271
 272         if (sfd->vm_ops->get_policy)
 273                 pol = sfd->vm_ops->get_policy(vma, addr);
 274         else if (vma->vm_policy)
 275                 pol = vma->vm_policy;
 276
 277         return pol;
 278 }
 279 #endif
 280
 281 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
 282 {
 283         struct shm_file_data *sfd = shm_file_data(file);
 284         int ret;
 285
 286         ret = sfd->file->f_op->mmap(sfd->file, vma);
 287         if (ret != 0)
 288                 return ret;
 289         sfd->vm_ops = vma->vm_ops;
 290 #ifdef CONFIG_MMU
 291         BUG_ON(!sfd->vm_ops->fault);
 292 #endif
 293         vma->vm_ops = &shm_vm_ops;
 294         shm_open(vma);
 295
 296         return ret;
 297 }
 298
 299 static int shm_release(struct inode *ino, struct file *file)
 300 {
 301         struct shm_file_data *sfd = shm_file_data(file);
 302
 303         put_ipc_ns(sfd->ns);
 304         shm_file_data(file) = NULL;
 305         kfree(sfd);
 306         return 0;
 307 }
 308
 309 static int shm_fsync(struct file *file, struct dentry *dentry, int datasync)
 310 {
 311         int (*fsync) (struct file *, struct dentry *, int datasync);
 312         struct shm_file_data *sfd = shm_file_data(file);
 313         int ret = -EINVAL;
 314
 315         fsync = sfd->file->f_op->fsync;
 316         if (fsync)
 317                 ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync);
 318         return ret;
 319 }
 320
 321 static unsigned long shm_get_unmapped_area(struct file *file,
 322         unsigned long addr, unsigned long len, unsigned long pgoff,
 323         unsigned long flags)
 324 {
 325         struct shm_file_data *sfd = shm_file_data(file);
 326         return get_unmapped_area(sfd->file, addr, len, pgoff, flags);
 327 }
 328
 329 int is_file_shm_hugepages(struct file *file)
 330 {
 331         int ret = 0;
 332
 333         if (file->f_op == &shm_file_operations) {
 334                 struct shm_file_data *sfd;
 335                 sfd = shm_file_data(file);
 336                 ret = is_file_hugepages(sfd->file);
 337         }
 338         return ret;
 339 }
 340
 341 static const struct file_operations shm_file_operations = {
 342         .mmap           = shm_mmap,
 343         .fsync          = shm_fsync,
 344         .release        = shm_release,
 345         .get_unmapped_area      = shm_get_unmapped_area,
 346 };
 347
 348 static struct vm_operations_struct shm_vm_ops = {
 349         .open   = shm_open,     /* callback for a new vm-area open */
 350         .close  = shm_close,    /* callback for when the vm-area is released */
 351         .fault  = shm_fault,
 352 #if defined(CONFIG_NUMA)
 353         .set_policy = shm_set_policy,
 354         .get_policy = shm_get_policy,
 355 #endif
 356 };
 357
 358 /**
 359  * newseg - Create a new shared memory segment
 360  * @ns: namespace
 361  * @params: ptr to the structure that contains key, size and shmflg
 362  *
 363  * Called with shm_ids.rw_mutex held as a writer.
 364  */
 365
 366 static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
 367 {
 368         key_t key = params->key;
 369         int shmflg = params->flg;
 370         size_t size = params->u.size;
 371         int error;
 372         struct shmid_kernel *shp;
 373         int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
 374         struct file * file;
 375         char name[13];
 376         int id;
 377
 378         if (size < SHMMIN || size > ns->shm_ctlmax)
 379                 return -EINVAL;
 380
 381         if (ns->shm_tot + numpages > ns->shm_ctlall)
 382                 return -ENOSPC;
 383
 384         shp = ipc_rcu_alloc(sizeof(*shp));
 385         if (!shp)
 386                 return -ENOMEM;
 387
 388         shp->shm_perm.key = key;
 389         shp->shm_perm.mode = (shmflg & S_IRWXUGO);
 390         shp->mlock_user = NULL;
 391
 392         shp->shm_perm.security = NULL;
 393         error = security_shm_alloc(shp);
 394         if (error) {
 395                 ipc_rcu_putref(shp);
 396                 return error;
 397         }
 398
 399         sprintf (name, "SYSV%08x", key);
 400         if (shmflg & SHM_HUGETLB) {
 401                 /* hugetlb_file_setup takes care of mlock user accounting */
 402                 file = hugetlb_file_setup(name, size);
 403                 shp->mlock_user = current->user;
 404         } else {
 405                 int acctflag = VM_ACCOUNT;
 406                 /*
 407                  * Do not allow no accounting for OVERCOMMIT_NEVER, even
 408                  * if it's asked for.
 409                  */
 410                 if  ((shmflg & SHM_NORESERVE) &&
 411                                 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
 412                         acctflag = 0;
 413                 file = shmem_file_setup(name, size, acctflag);
 414         }
 415         error = PTR_ERR(file);
 416         if (IS_ERR(file))
 417                 goto no_file;
 418
 419         id = shm_addid(ns, shp);
 420         if (id < 0) {
 421                 error = id;
 422                 goto no_id;
 423         }
 424
 425         shp->shm_cprid = task_tgid_vnr(current);
 426         shp->shm_lprid = 0;
 427         shp->shm_atim = shp->shm_dtim = 0;
 428         shp->shm_ctim = get_seconds();
 429         shp->shm_segsz = size;
 430         shp->shm_nattch = 0;
 431         shp->shm_perm.id = shm_buildid(id, shp->shm_perm.seq);
 432         shp->shm_file = file;
 433         /*
 434          * shmid gets reported as "inode#" in /proc/pid/maps.
 435          * proc-ps tools use this. Changing this will break them.
 436          */
 437         file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
 438
 439         ns->shm_tot += numpages;
 440         error = shp->shm_perm.id;
 441         shm_unlock(shp);
 442         return error;
 443
 444 no_id:
 445         fput(file);
 446 no_file:
 447         security_shm_free(shp);
 448         ipc_rcu_putref(shp);
 449         return error;
 450 }
 451
 452 /*
 453  * Called with shm_ids.rw_mutex and ipcp locked.
 454  */
 455 static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
 456 {
 457         struct shmid_kernel *shp;
 458
 459         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 460         return security_shm_associate(shp, shmflg);
 461 }
 462
 463 /*
 464  * Called with shm_ids.rw_mutex and ipcp locked.
 465  */
 466 static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
 467                                 struct ipc_params *params)
 468 {
 469         struct shmid_kernel *shp;
 470
 471         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 472         if (shp->shm_segsz < params->u.size)
 473                 return -EINVAL;
 474
 475         return 0;
 476 }
 477
 478 asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
 479 {
 480         struct ipc_namespace *ns;
 481         struct ipc_ops shm_ops;
 482         struct ipc_params shm_params;
 483
 484         ns = current->nsproxy->ipc_ns;
 485
 486         shm_ops.getnew = newseg;
 487         shm_ops.associate = shm_security;
 488         shm_ops.more_checks = shm_more_checks;
 489
 490         shm_params.key = key;
 491         shm_params.flg = shmflg;
 492         shm_params.u.size = size;
 493
 494         return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
 495 }
 496
 497 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
 498 {
 499         switch(version) {
 500         case IPC_64:
 501                 return copy_to_user(buf, in, sizeof(*in));
 502         case IPC_OLD:
 503             {
 504                 struct shmid_ds out;
 505
 506                 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
 507                 out.shm_segsz   = in->shm_segsz;
 508                 out.shm_atime   = in->shm_atime;
 509                 out.shm_dtime   = in->shm_dtime;
 510                 out.shm_ctime   = in->shm_ctime;
 511                 out.shm_cpid    = in->shm_cpid;
 512                 out.shm_lpid    = in->shm_lpid;
 513                 out.shm_nattch  = in->shm_nattch;
 514
 515                 return copy_to_user(buf, &out, sizeof(out));
 516             }
 517         default:
 518                 return -EINVAL;
 519         }
 520 }
 521
 522 struct shm_setbuf {
 523         uid_t   uid;
 524         gid_t   gid;
 525         mode_t  mode;
 526 };
 527
 528 static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
 529 {
 530         switch(version) {
 531         case IPC_64:
 532             {
 533                 struct shmid64_ds tbuf;
 534
 535                 if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
 536                         return -EFAULT;
 537
 538                 out->uid        = tbuf.shm_perm.uid;
 539                 out->gid        = tbuf.shm_perm.gid;
 540                 out->mode       = tbuf.shm_perm.mode;
 541
 542                 return 0;
 543             }
 544         case IPC_OLD:
 545             {
 546                 struct shmid_ds tbuf_old;
 547
 548                 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
 549                         return -EFAULT;
 550
 551                 out->uid        = tbuf_old.shm_perm.uid;
 552                 out->gid        = tbuf_old.shm_perm.gid;
 553                 out->mode       = tbuf_old.shm_perm.mode;
 554
 555                 return 0;
 556             }
 557         default:
 558                 return -EINVAL;
 559         }
 560 }
 561
 562 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
 563 {
 564         switch(version) {
 565         case IPC_64:
 566                 return copy_to_user(buf, in, sizeof(*in));
 567         case IPC_OLD:
 568             {
 569                 struct shminfo out;
 570
 571                 if(in->shmmax > INT_MAX)
 572                         out.shmmax = INT_MAX;
 573                 else
 574                         out.shmmax = (int)in->shmmax;
 575
 576                 out.shmmin      = in->shmmin;
 577                 out.shmmni      = in->shmmni;
 578                 out.shmseg      = in->shmseg;
 579                 out.shmall      = in->shmall;
 580
 581                 return copy_to_user(buf, &out, sizeof(out));
 582             }
 583         default:
 584                 return -EINVAL;
 585         }
 586 }
 587
 588 /*
 589  * Called with shm_ids.rw_mutex held as a reader
 590  */
 591 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
 592                 unsigned long *swp)
 593 {
 594         int next_id;
 595         int total, in_use;
 596
 597         *rss = 0;
 598         *swp = 0;
 599
 600         in_use = shm_ids(ns).in_use;
 601
 602         for (total = 0, next_id = 0; total < in_use; next_id++) {
 603                 struct shmid_kernel *shp;
 604                 struct inode *inode;
 605
 606                 shp = idr_find(&shm_ids(ns).ipcs_idr, next_id);
 607                 if (shp == NULL)
 608                         continue;
 609
 610                 inode = shp->shm_file->f_path.dentry->d_inode;
 611
 612                 if (is_file_hugepages(shp->shm_file)) {
 613                         struct address_space *mapping = inode->i_mapping;
 614                         *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
 615                 } else {
 616                         struct shmem_inode_info *info = SHMEM_I(inode);
 617                         spin_lock(&info->lock);
 618                         *rss += inode->i_mapping->nrpages;
 619                         *swp += info->swapped;
 620                         spin_unlock(&info->lock);
 621                 }
 622
 623                 total++;
 624         }
 625 }
 626
 627 asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
 628 {
 629         struct shm_setbuf setbuf;
 630         struct shmid_kernel *shp;
 631         int err, version;
 632         struct ipc_namespace *ns;
 633
 634         if (cmd < 0 || shmid < 0) {
 635                 err = -EINVAL;
 636                 goto out;
 637         }
 638
 639         version = ipc_parse_version(&cmd);
 640         ns = current->nsproxy->ipc_ns;
 641
 642         switch (cmd) { /* replace with proc interface ? */
 643         case IPC_INFO:
 644         {
 645                 struct shminfo64 shminfo;
 646
 647                 err = security_shm_shmctl(NULL, cmd);
 648                 if (err)
 649                         return err;
 650
 651                 memset(&shminfo,0,sizeof(shminfo));
 652                 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
 653                 shminfo.shmmax = ns->shm_ctlmax;
 654                 shminfo.shmall = ns->shm_ctlall;
 655
 656                 shminfo.shmmin = SHMMIN;
 657                 if(copy_shminfo_to_user (buf, &shminfo, version))
 658                         return -EFAULT;
 659
 660                 down_read(&shm_ids(ns).rw_mutex);
 661                 err = ipc_get_maxid(&shm_ids(ns));
 662                 up_read(&shm_ids(ns).rw_mutex);
 663
 664                 if(err<0)
 665                         err = 0;
 666                 goto out;
 667         }
 668         case SHM_INFO:
 669         {
 670                 struct shm_info shm_info;
 671
 672                 err = security_shm_shmctl(NULL, cmd);
 673                 if (err)
 674                         return err;
 675
 676                 memset(&shm_info,0,sizeof(shm_info));
 677                 down_read(&shm_ids(ns).rw_mutex);
 678                 shm_info.used_ids = shm_ids(ns).in_use;
 679                 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
 680                 shm_info.shm_tot = ns->shm_tot;
 681                 shm_info.swap_attempts = 0;
 682                 shm_info.swap_successes = 0;
 683                 err = ipc_get_maxid(&shm_ids(ns));
 684                 up_read(&shm_ids(ns).rw_mutex);
 685                 if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
 686                         err = -EFAULT;
 687                         goto out;
 688                 }
 689
 690                 err = err < 0 ? 0 : err;
 691                 goto out;
 692         }
 693         case SHM_STAT:
 694         case IPC_STAT:
 695         {
 696                 struct shmid64_ds tbuf;
 697                 int result;
 698
 699                 if (!buf) {
 700                         err = -EFAULT;
 701                         goto out;
 702                 }
 703
 704                 if (cmd == SHM_STAT) {
 705                         shp = shm_lock(ns, shmid);
 706                         if (IS_ERR(shp)) {
 707                                 err = PTR_ERR(shp);
 708                                 goto out;
 709                         }
 710                         result = shp->shm_perm.id;
 711                 } else {
 712                         shp = shm_lock_check(ns, shmid);
 713                         if (IS_ERR(shp)) {
 714                                 err = PTR_ERR(shp);
 715                                 goto out;
 716                         }
 717                         result = 0;
 718                 }
 719                 err=-EACCES;
 720                 if (ipcperms (&shp->shm_perm, S_IRUGO))
 721                         goto out_unlock;
 722                 err = security_shm_shmctl(shp, cmd);
 723                 if (err)
 724                         goto out_unlock;
 725                 memset(&tbuf, 0, sizeof(tbuf));
 726                 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
 727                 tbuf.shm_segsz  = shp->shm_segsz;
 728                 tbuf.shm_atime  = shp->shm_atim;
 729                 tbuf.shm_dtime  = shp->shm_dtim;
 730                 tbuf.shm_ctime  = shp->shm_ctim;
 731                 tbuf.shm_cpid   = shp->shm_cprid;
 732                 tbuf.shm_lpid   = shp->shm_lprid;
 733                 tbuf.shm_nattch = shp->shm_nattch;
 734                 shm_unlock(shp);
 735                 if(copy_shmid_to_user (buf, &tbuf, version))
 736                         err = -EFAULT;
 737                 else
 738                         err = result;
 739                 goto out;
 740         }
 741         case SHM_LOCK:
 742         case SHM_UNLOCK:
 743         {
 744                 shp = shm_lock_check(ns, shmid);
 745                 if (IS_ERR(shp)) {
 746                         err = PTR_ERR(shp);
 747                         goto out;
 748                 }
 749
 750                 err = audit_ipc_obj(&(shp->shm_perm));
 751                 if (err)
 752                         goto out_unlock;
 753
 754                 if (!capable(CAP_IPC_LOCK)) {
 755                         err = -EPERM;
 756                         if (current->euid != shp->shm_perm.uid &&
 757                             current->euid != shp->shm_perm.cuid)
 758                                 goto out_unlock;
 759                         if (cmd == SHM_LOCK &&
 760                             !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
 761                                 goto out_unlock;
 762                 }
 763
 764                 err = security_shm_shmctl(shp, cmd);
 765                 if (err)
 766                         goto out_unlock;
 767
 768                 if(cmd==SHM_LOCK) {
 769                         struct user_struct * user = current->user;
 770                         if (!is_file_hugepages(shp->shm_file)) {
 771                                 err = shmem_lock(shp->shm_file, 1, user);
 772                                 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
 773                                         shp->shm_perm.mode |= SHM_LOCKED;
 774                                         shp->mlock_user = user;
 775                                 }
 776                         }
 777                 } else if (!is_file_hugepages(shp->shm_file)) {
 778                         shmem_lock(shp->shm_file, 0, shp->mlock_user);
 779                         shp->shm_perm.mode &= ~SHM_LOCKED;
 780                         shp->mlock_user = NULL;
 781                 }
 782                 shm_unlock(shp);
 783                 goto out;
 784         }
 785         case IPC_RMID:
 786         {
 787                 /*
 788                  *      We cannot simply remove the file. The SVID states
 789                  *      that the block remains until the last person
 790                  *      detaches from it, then is deleted. A shmat() on
 791                  *      an RMID segment is legal in older Linux and if
 792                  *      we change it apps break...
 793                  *
 794                  *      Instead we set a destroyed flag, and then blow
 795                  *      the name away when the usage hits zero.
 796                  */
 797                 down_write(&shm_ids(ns).rw_mutex);
 798                 shp = shm_lock_check_down(ns, shmid);
 799                 if (IS_ERR(shp)) {
 800                         err = PTR_ERR(shp);
 801                         goto out_up;
 802                 }
 803
 804                 err = audit_ipc_obj(&(shp->shm_perm));
 805                 if (err)
 806                         goto out_unlock_up;
 807
 808                 if (current->euid != shp->shm_perm.uid &&
 809                     current->euid != shp->shm_perm.cuid &&
 810                     !capable(CAP_SYS_ADMIN)) {
 811                         err=-EPERM;
 812                         goto out_unlock_up;
 813                 }
 814
 815                 err = security_shm_shmctl(shp, cmd);
 816                 if (err)
 817                         goto out_unlock_up;
 818
 819                 do_shm_rmid(ns, &shp->shm_perm);
 820                 up_write(&shm_ids(ns).rw_mutex);
 821                 goto out;
 822         }
 823
 824         case IPC_SET:
 825         {
 826                 if (!buf) {
 827                         err = -EFAULT;
 828                         goto out;
 829                 }
 830
 831                 if (copy_shmid_from_user (&setbuf, buf, version)) {
 832                         err = -EFAULT;
 833                         goto out;
 834                 }
 835                 down_write(&shm_ids(ns).rw_mutex);
 836                 shp = shm_lock_check_down(ns, shmid);
 837                 if (IS_ERR(shp)) {
 838                         err = PTR_ERR(shp);
 839                         goto out_up;
 840                 }
 841                 err = audit_ipc_obj(&(shp->shm_perm));
 842                 if (err)
 843                         goto out_unlock_up;
 844                 err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode);
 845                 if (err)
 846                         goto out_unlock_up;
 847                 err=-EPERM;
 848                 if (current->euid != shp->shm_perm.uid &&
 849                     current->euid != shp->shm_perm.cuid &&
 850                     !capable(CAP_SYS_ADMIN)) {
 851                         goto out_unlock_up;
 852                 }
 853
 854                 err = security_shm_shmctl(shp, cmd);
 855                 if (err)
 856                         goto out_unlock_up;
 857
 858                 shp->shm_perm.uid = setbuf.uid;
 859                 shp->shm_perm.gid = setbuf.gid;
 860                 shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO)
 861                         | (setbuf.mode & S_IRWXUGO);
 862                 shp->shm_ctim = get_seconds();
 863                 break;
 864         }
 865
 866         default:
 867                 err = -EINVAL;
 868                 goto out;
 869         }
 870
 871         err = 0;
 872 out_unlock_up:
 873         shm_unlock(shp);
 874 out_up:
 875         up_write(&shm_ids(ns).rw_mutex);
 876         goto out;
 877 out_unlock:
 878         shm_unlock(shp);
 879 out:
 880         return err;
 881 }
 882
 883 /*
 884  * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
 885  *
 886  * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
 887  * "raddr" thing points to kernel space, and there has to be a wrapper around
 888  * this.
 889  */
 890 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
 891 {
 892         struct shmid_kernel *shp;
 893         unsigned long addr;
 894         unsigned long size;
 895         struct file * file;
 896         int    err;
 897         unsigned long flags;
 898         unsigned long prot;
 899         int acc_mode;
 900         unsigned long user_addr;
 901         struct ipc_namespace *ns;
 902         struct shm_file_data *sfd;
 903         struct path path;
 904         mode_t f_mode;
 905
 906         err = -EINVAL;
 907         if (shmid < 0)
 908                 goto out;
 909         else if ((addr = (ulong)shmaddr)) {
 910                 if (addr & (SHMLBA-1)) {
 911                         if (shmflg & SHM_RND)
 912                                 addr &= ~(SHMLBA-1);       /* round down */
 913                         else
 914 #ifndef __ARCH_FORCE_SHMLBA
 915                                 if (addr & ~PAGE_MASK)
 916 #endif
 917                                         goto out;
 918                 }
 919                 flags = MAP_SHARED | MAP_FIXED;
 920         } else {
 921                 if ((shmflg & SHM_REMAP))
 922                         goto out;
 923
 924                 flags = MAP_SHARED;
 925         }
 926
 927         if (shmflg & SHM_RDONLY) {
 928                 prot = PROT_READ;
 929                 acc_mode = S_IRUGO;
 930                 f_mode = FMODE_READ;
 931         } else {
 932                 prot = PROT_READ | PROT_WRITE;
 933                 acc_mode = S_IRUGO | S_IWUGO;
 934                 f_mode = FMODE_READ | FMODE_WRITE;
 935         }
 936         if (shmflg & SHM_EXEC) {
 937                 prot |= PROT_EXEC;
 938                 acc_mode |= S_IXUGO;
 939         }
 940
 941         /*
 942          * We cannot rely on the fs check since SYSV IPC does have an
 943          * additional creator id...
 944          */
 945         ns = current->nsproxy->ipc_ns;
 946         shp = shm_lock_check(ns, shmid);
 947         if (IS_ERR(shp)) {
 948                 err = PTR_ERR(shp);
 949                 goto out;
 950         }
 951
 952         err = -EACCES;
 953         if (ipcperms(&shp->shm_perm, acc_mode))
 954                 goto out_unlock;
 955
 956         err = security_shm_shmat(shp, shmaddr, shmflg);
 957         if (err)
 958                 goto out_unlock;
 959
 960         path.dentry = dget(shp->shm_file->f_path.dentry);
 961         path.mnt    = shp->shm_file->f_path.mnt;
 962         shp->shm_nattch++;
 963         size = i_size_read(path.dentry->d_inode);
 964         shm_unlock(shp);
 965
 966         err = -ENOMEM;
 967         sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
 968         if (!sfd)
 969                 goto out_put_dentry;
 970
 971         err = -ENOMEM;
 972
 973         file = alloc_file(path.mnt, path.dentry, f_mode, &shm_file_operations);
 974         if (!file)
 975                 goto out_free;
 976
 977         file->private_data = sfd;
 978         file->f_mapping = shp->shm_file->f_mapping;
 979         sfd->id = shp->shm_perm.id;
 980         sfd->ns = get_ipc_ns(ns);
 981         sfd->file = shp->shm_file;
 982         sfd->vm_ops = NULL;
 983
 984         down_write(&current->mm->mmap_sem);
 985         if (addr && !(shmflg & SHM_REMAP)) {
 986                 err = -EINVAL;
 987                 if (find_vma_intersection(current->mm, addr, addr + size))
 988                         goto invalid;
 989                 /*
 990                  * If shm segment goes below stack, make sure there is some
 991                  * space left for the stack to grow (at least 4 pages).
 992                  */
 993                 if (addr < current->mm->start_stack &&
 994                     addr > current->mm->start_stack - size - PAGE_SIZE * 5)
 995                         goto invalid;
 996         }
 997
 998         user_addr = do_mmap (file, addr, size, prot, flags, 0);
 999         *raddr = user_addr;
1000         err = 0;
1001         if (IS_ERR_VALUE(user_addr))
1002                 err = (long)user_addr;
1003 invalid:
1004         up_write(&current->mm->mmap_sem);
1005
1006         fput(file);
1007
1008 out_nattch:
1009         down_write(&shm_ids(ns).rw_mutex);
1010         shp = shm_lock_down(ns, shmid);
1011         BUG_ON(IS_ERR(shp));
1012         shp->shm_nattch--;
1013         if(shp->shm_nattch == 0 &&
1014            shp->shm_perm.mode & SHM_DEST)
1015                 shm_destroy(ns, shp);
1016         else
1017                 shm_unlock(shp);
1018         up_write(&shm_ids(ns).rw_mutex);
1019
1020 out:
1021         return err;
1022
1023 out_unlock:
1024         shm_unlock(shp);
1025         goto out;
1026
1027 out_free:
1028         kfree(sfd);
1029 out_put_dentry:
1030         dput(path.dentry);
1031         goto out_nattch;
1032 }
1033
1034 asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
1035 {
1036         unsigned long ret;
1037         long err;
1038
1039         err = do_shmat(shmid, shmaddr, shmflg, &ret);
1040         if (err)
1041                 return err;
1042         force_successful_syscall_return();
1043         return (long)ret;
1044 }
1045
1046 /*
1047  * detach and kill segment if marked destroyed.
1048  * The work is done in shm_close.
1049  */
1050 asmlinkage long sys_shmdt(char __user *shmaddr)
1051 {
1052         struct mm_struct *mm = current->mm;
1053         struct vm_area_struct *vma, *next;
1054         unsigned long addr = (unsigned long)shmaddr;
1055         loff_t size = 0;
1056         int retval = -EINVAL;
1057
1058         if (addr & ~PAGE_MASK)
1059                 return retval;
1060
1061         down_write(&mm->mmap_sem);
1062
1063         /*
1064          * This function tries to be smart and unmap shm segments that
1065          * were modified by partial mlock or munmap calls:
1066          * - It first determines the size of the shm segment that should be
1067          *   unmapped: It searches for a vma that is backed by shm and that
1068          *   started at address shmaddr. It records it's size and then unmaps
1069          *   it.
1070          * - Then it unmaps all shm vmas that started at shmaddr and that
1071          *   are within the initially determined size.
1072          * Errors from do_munmap are ignored: the function only fails if
1073          * it's called with invalid parameters or if it's called to unmap
1074          * a part of a vma. Both calls in this function are for full vmas,
1075          * the parameters are directly copied from the vma itself and always
1076          * valid - therefore do_munmap cannot fail. (famous last words?)
1077          */
1078         /*
1079          * If it had been mremap()'d, the starting address would not
1080          * match the usual checks anyway. So assume all vma's are
1081          * above the starting address given.
1082          */
1083         vma = find_vma(mm, addr);
1084
1085         while (vma) {
1086                 next = vma->vm_next;
1087
1088                 /*
1089                  * Check if the starting address would match, i.e. it's
1090                  * a fragment created by mprotect() and/or munmap(), or it
1091                  * otherwise it starts at this address with no hassles.
1092                  */
1093                 if ((vma->vm_ops == &shm_vm_ops) &&
1094                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1095
1096
1097                         size = vma->vm_file->f_path.dentry->d_inode->i_size;
1098                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1099                         /*
1100                          * We discovered the size of the shm segment, so
1101                          * break out of here and fall through to the next
1102                          * loop that uses the size information to stop
1103                          * searching for matching vma's.
1104                          */
1105                         retval = 0;
1106                         vma = next;
1107                         break;
1108                 }
1109                 vma = next;
1110         }
1111
1112         /*
1113          * We need look no further than the maximum address a fragment
1114          * could possibly have landed at. Also cast things to loff_t to
1115          * prevent overflows and make comparisions vs. equal-width types.
1116          */
1117         size = PAGE_ALIGN(size);
1118         while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1119                 next = vma->vm_next;
1120
1121                 /* finding a matching vma now does not alter retval */
1122                 if ((vma->vm_ops == &shm_vm_ops) &&
1123                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1124
1125                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1126                 vma = next;
1127         }
1128
1129         up_write(&mm->mmap_sem);
1130         return retval;
1131 }
1132
1133 #ifdef CONFIG_PROC_FS
1134 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1135 {
1136         struct shmid_kernel *shp = it;
1137         char *format;
1138
1139 #define SMALL_STRING "%10d %10d  %4o %10u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1140 #define BIG_STRING   "%10d %10d  %4o %21u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1141
1142         if (sizeof(size_t) <= sizeof(int))
1143                 format = SMALL_STRING;
1144         else
1145                 format = BIG_STRING;
1146         return seq_printf(s, format,
1147                           shp->shm_perm.key,
1148                           shp->shm_perm.id,
1149                           shp->shm_perm.mode,
1150                           shp->shm_segsz,
1151                           shp->shm_cprid,
1152                           shp->shm_lprid,
1153                           shp->shm_nattch,
1154                           shp->shm_perm.uid,
1155                           shp->shm_perm.gid,
1156                           shp->shm_perm.cuid,
1157                           shp->shm_perm.cgid,
1158                           shp->shm_atim,
1159                           shp->shm_dtim,
1160                           shp->shm_ctim);
1161 }
1162 #endif