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 #if BITS_PER_LONG <= 32
 112                                 "       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime        rss       swap\n",
 113 #else
 114                                 "       key      shmid perms                  size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime                   rss                  swap\n",
 115 #endif
 116                                 IPC_SHM_IDS, sysvipc_shm_proc_show);
 117 }
 118
 119 /*
 120  * shm_lock_(check_) routines are called in the paths where the rw_mutex
 121  * is not necessarily held.
 122  */
 123 static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
 124 {
 125         struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
 126
 127         if (IS_ERR(ipcp))
 128                 return (struct shmid_kernel *)ipcp;
 129
 130         return container_of(ipcp, struct shmid_kernel, shm_perm);
 131 }
 132
 133 static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
 134                                                 int id)
 135 {
 136         struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id);
 137
 138         if (IS_ERR(ipcp))
 139                 return (struct shmid_kernel *)ipcp;
 140
 141         return container_of(ipcp, struct shmid_kernel, shm_perm);
 142 }
 143
 144 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
 145 {
 146         ipc_rmid(&shm_ids(ns), &s->shm_perm);
 147 }
 148
 149
 150 /* This is called by fork, once for every shm attach. */
 151 static void shm_open(struct vm_area_struct *vma)
 152 {
 153         struct file *file = vma->vm_file;
 154         struct shm_file_data *sfd = shm_file_data(file);
 155         struct shmid_kernel *shp;
 156
 157         shp = shm_lock(sfd->ns, sfd->id);
 158         BUG_ON(IS_ERR(shp));
 159         shp->shm_atim = get_seconds();
 160         shp->shm_lprid = task_tgid_vnr(current);
 161         shp->shm_nattch++;
 162         shm_unlock(shp);
 163 }
 164
 165 /*
 166  * shm_destroy - free the struct shmid_kernel
 167  *
 168  * @ns: namespace
 169  * @shp: struct to free
 170  *
 171  * It has to be called with shp and shm_ids.rw_mutex (writer) locked,
 172  * but returns with shp unlocked and freed.
 173  */
 174 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
 175 {
 176         ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
 177         shm_rmid(ns, shp);
 178         shm_unlock(shp);
 179         if (!is_file_hugepages(shp->shm_file))
 180                 shmem_lock(shp->shm_file, 0, shp->mlock_user);
 181         else if (shp->mlock_user)
 182                 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
 183                                                 shp->mlock_user);
 184         fput (shp->shm_file);
 185         security_shm_free(shp);
 186         ipc_rcu_putref(shp);
 187 }
 188
 189 /*
 190  * remove the attach descriptor vma.
 191  * free memory for segment if it is marked destroyed.
 192  * The descriptor has already been removed from the current->mm->mmap list
 193  * and will later be kfree()d.
 194  */
 195 static void shm_close(struct vm_area_struct *vma)
 196 {
 197         struct file * file = vma->vm_file;
 198         struct shm_file_data *sfd = shm_file_data(file);
 199         struct shmid_kernel *shp;
 200         struct ipc_namespace *ns = sfd->ns;
 201
 202         down_write(&shm_ids(ns).rw_mutex);
 203         /* remove from the list of attaches of the shm segment */
 204         shp = shm_lock(ns, sfd->id);
 205         BUG_ON(IS_ERR(shp));
 206         shp->shm_lprid = task_tgid_vnr(current);
 207         shp->shm_dtim = get_seconds();
 208         shp->shm_nattch--;
 209         if(shp->shm_nattch == 0 &&
 210            shp->shm_perm.mode & SHM_DEST)
 211                 shm_destroy(ns, shp);
 212         else
 213                 shm_unlock(shp);
 214         up_write(&shm_ids(ns).rw_mutex);
 215 }
 216
 217 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 218 {
 219         struct file *file = vma->vm_file;
 220         struct shm_file_data *sfd = shm_file_data(file);
 221
 222         return sfd->vm_ops->fault(vma, vmf);
 223 }
 224
 225 #ifdef CONFIG_NUMA
 226 static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
 227 {
 228         struct file *file = vma->vm_file;
 229         struct shm_file_data *sfd = shm_file_data(file);
 230         int err = 0;
 231         if (sfd->vm_ops->set_policy)
 232                 err = sfd->vm_ops->set_policy(vma, new);
 233         return err;
 234 }
 235
 236 static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
 237                                         unsigned long addr)
 238 {
 239         struct file *file = vma->vm_file;
 240         struct shm_file_data *sfd = shm_file_data(file);
 241         struct mempolicy *pol = NULL;
 242
 243         if (sfd->vm_ops->get_policy)
 244                 pol = sfd->vm_ops->get_policy(vma, addr);
 245         else if (vma->vm_policy)
 246                 pol = vma->vm_policy;
 247
 248         return pol;
 249 }
 250 #endif
 251
 252 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
 253 {
 254         struct shm_file_data *sfd = shm_file_data(file);
 255         int ret;
 256
 257         ret = sfd->file->f_op->mmap(sfd->file, vma);
 258         if (ret != 0)
 259                 return ret;
 260         sfd->vm_ops = vma->vm_ops;
 261 #ifdef CONFIG_MMU
 262         BUG_ON(!sfd->vm_ops->fault);
 263 #endif
 264         vma->vm_ops = &shm_vm_ops;
 265         shm_open(vma);
 266
 267         return ret;
 268 }
 269
 270 static int shm_release(struct inode *ino, struct file *file)
 271 {
 272         struct shm_file_data *sfd = shm_file_data(file);
 273
 274         put_ipc_ns(sfd->ns);
 275         shm_file_data(file) = NULL;
 276         kfree(sfd);
 277         return 0;
 278 }
 279
 280 static int shm_fsync(struct file *file, int datasync)
 281 {
 282         struct shm_file_data *sfd = shm_file_data(file);
 283
 284         if (!sfd->file->f_op->fsync)
 285                 return -EINVAL;
 286         return sfd->file->f_op->fsync(sfd->file, datasync);
 287 }
 288
 289 static unsigned long shm_get_unmapped_area(struct file *file,
 290         unsigned long addr, unsigned long len, unsigned long pgoff,
 291         unsigned long flags)
 292 {
 293         struct shm_file_data *sfd = shm_file_data(file);
 294         return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
 295                                                 pgoff, flags);
 296 }
 297
 298 static const struct file_operations shm_file_operations = {
 299         .mmap           = shm_mmap,
 300         .fsync          = shm_fsync,
 301         .release        = shm_release,
 302 #ifndef CONFIG_MMU
 303         .get_unmapped_area      = shm_get_unmapped_area,
 304 #endif
 305         .llseek         = noop_llseek,
 306 };
 307
 308 static const struct file_operations shm_file_operations_huge = {
 309         .mmap           = shm_mmap,
 310         .fsync          = shm_fsync,
 311         .release        = shm_release,
 312         .get_unmapped_area      = shm_get_unmapped_area,
 313         .llseek         = noop_llseek,
 314 };
 315
 316 int is_file_shm_hugepages(struct file *file)
 317 {
 318         return file->f_op == &shm_file_operations_huge;
 319 }
 320
 321 static const struct vm_operations_struct shm_vm_ops = {
 322         .open   = shm_open,     /* callback for a new vm-area open */
 323         .close  = shm_close,    /* callback for when the vm-area is released */
 324         .fault  = shm_fault,
 325 #if defined(CONFIG_NUMA)
 326         .set_policy = shm_set_policy,
 327         .get_policy = shm_get_policy,
 328 #endif
 329 };
 330
 331 /**
 332  * newseg - Create a new shared memory segment
 333  * @ns: namespace
 334  * @params: ptr to the structure that contains key, size and shmflg
 335  *
 336  * Called with shm_ids.rw_mutex held as a writer.
 337  */
 338
 339 static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
 340 {
 341         key_t key = params->key;
 342         int shmflg = params->flg;
 343         size_t size = params->u.size;
 344         int error;
 345         struct shmid_kernel *shp;
 346         int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
 347         struct file * file;
 348         char name[13];
 349         int id;
 350         int acctflag = 0;
 351
 352         if (size < SHMMIN || size > ns->shm_ctlmax)
 353                 return -EINVAL;
 354
 355         if (ns->shm_tot + numpages > ns->shm_ctlall)
 356                 return -ENOSPC;
 357
 358         shp = ipc_rcu_alloc(sizeof(*shp));
 359         if (!shp)
 360                 return -ENOMEM;
 361
 362         shp->shm_perm.key = key;
 363         shp->shm_perm.mode = (shmflg & S_IRWXUGO);
 364         shp->mlock_user = NULL;
 365
 366         shp->shm_perm.security = NULL;
 367         error = security_shm_alloc(shp);
 368         if (error) {
 369                 ipc_rcu_putref(shp);
 370                 return error;
 371         }
 372
 373         sprintf (name, "SYSV%08x", key);
 374         if (shmflg & SHM_HUGETLB) {
 375                 /* hugetlb_file_setup applies strict accounting */
 376                 if (shmflg & SHM_NORESERVE)
 377                         acctflag = VM_NORESERVE;
 378                 file = hugetlb_file_setup(name, size, acctflag,
 379                                         &shp->mlock_user, HUGETLB_SHMFS_INODE);
 380         } else {
 381                 /*
 382                  * Do not allow no accounting for OVERCOMMIT_NEVER, even
 383                  * if it's asked for.
 384                  */
 385                 if  ((shmflg & SHM_NORESERVE) &&
 386                                 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
 387                         acctflag = VM_NORESERVE;
 388                 file = shmem_file_setup(name, size, acctflag);
 389         }
 390         error = PTR_ERR(file);
 391         if (IS_ERR(file))
 392                 goto no_file;
 393
 394         id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
 395         if (id < 0) {
 396                 error = id;
 397                 goto no_id;
 398         }
 399
 400         shp->shm_cprid = task_tgid_vnr(current);
 401         shp->shm_lprid = 0;
 402         shp->shm_atim = shp->shm_dtim = 0;
 403         shp->shm_ctim = get_seconds();
 404         shp->shm_segsz = size;
 405         shp->shm_nattch = 0;
 406         shp->shm_file = file;
 407         /*
 408          * shmid gets reported as "inode#" in /proc/pid/maps.
 409          * proc-ps tools use this. Changing this will break them.
 410          */
 411         file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
 412
 413         ns->shm_tot += numpages;
 414         error = shp->shm_perm.id;
 415         shm_unlock(shp);
 416         return error;
 417
 418 no_id:
 419         if (is_file_hugepages(file) && shp->mlock_user)
 420                 user_shm_unlock(size, shp->mlock_user);
 421         fput(file);
 422 no_file:
 423         security_shm_free(shp);
 424         ipc_rcu_putref(shp);
 425         return error;
 426 }
 427
 428 /*
 429  * Called with shm_ids.rw_mutex and ipcp locked.
 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 /*
 440  * Called with shm_ids.rw_mutex and ipcp locked.
 441  */
 442 static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
 443                                 struct ipc_params *params)
 444 {
 445         struct shmid_kernel *shp;
 446
 447         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 448         if (shp->shm_segsz < params->u.size)
 449                 return -EINVAL;
 450
 451         return 0;
 452 }
 453
 454 SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
 455 {
 456         struct ipc_namespace *ns;
 457         struct ipc_ops shm_ops;
 458         struct ipc_params shm_params;
 459
 460         ns = current->nsproxy->ipc_ns;
 461
 462         shm_ops.getnew = newseg;
 463         shm_ops.associate = shm_security;
 464         shm_ops.more_checks = shm_more_checks;
 465
 466         shm_params.key = key;
 467         shm_params.flg = shmflg;
 468         shm_params.u.size = size;
 469
 470         return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
 471 }
 472
 473 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
 474 {
 475         switch(version) {
 476         case IPC_64:
 477                 return copy_to_user(buf, in, sizeof(*in));
 478         case IPC_OLD:
 479             {
 480                 struct shmid_ds out;
 481
 482                 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
 483                 out.shm_segsz   = in->shm_segsz;
 484                 out.shm_atime   = in->shm_atime;
 485                 out.shm_dtime   = in->shm_dtime;
 486                 out.shm_ctime   = in->shm_ctime;
 487                 out.shm_cpid    = in->shm_cpid;
 488                 out.shm_lpid    = in->shm_lpid;
 489                 out.shm_nattch  = in->shm_nattch;
 490
 491                 return copy_to_user(buf, &out, sizeof(out));
 492             }
 493         default:
 494                 return -EINVAL;
 495         }
 496 }
 497
 498 static inline unsigned long
 499 copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
 500 {
 501         switch(version) {
 502         case IPC_64:
 503                 if (copy_from_user(out, buf, sizeof(*out)))
 504                         return -EFAULT;
 505                 return 0;
 506         case IPC_OLD:
 507             {
 508                 struct shmid_ds tbuf_old;
 509
 510                 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
 511                         return -EFAULT;
 512
 513                 out->shm_perm.uid       = tbuf_old.shm_perm.uid;
 514                 out->shm_perm.gid       = tbuf_old.shm_perm.gid;
 515                 out->shm_perm.mode      = tbuf_old.shm_perm.mode;
 516
 517                 return 0;
 518             }
 519         default:
 520                 return -EINVAL;
 521         }
 522 }
 523
 524 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
 525 {
 526         switch(version) {
 527         case IPC_64:
 528                 return copy_to_user(buf, in, sizeof(*in));
 529         case IPC_OLD:
 530             {
 531                 struct shminfo out;
 532
 533                 if(in->shmmax > INT_MAX)
 534                         out.shmmax = INT_MAX;
 535                 else
 536                         out.shmmax = (int)in->shmmax;
 537
 538                 out.shmmin      = in->shmmin;
 539                 out.shmmni      = in->shmmni;
 540                 out.shmseg      = in->shmseg;
 541                 out.shmall      = in->shmall;
 542
 543                 return copy_to_user(buf, &out, sizeof(out));
 544             }
 545         default:
 546                 return -EINVAL;
 547         }
 548 }
 549
 550 /*
 551  * Calculate and add used RSS and swap pages of a shm.
 552  * Called with shm_ids.rw_mutex held as a reader
 553  */
 554 static void shm_add_rss_swap(struct shmid_kernel *shp,
 555         unsigned long *rss_add, unsigned long *swp_add)
 556 {
 557         struct inode *inode;
 558
 559         inode = shp->shm_file->f_path.dentry->d_inode;
 560
 561         if (is_file_hugepages(shp->shm_file)) {
 562                 struct address_space *mapping = inode->i_mapping;
 563                 struct hstate *h = hstate_file(shp->shm_file);
 564                 *rss_add += pages_per_huge_page(h) * mapping->nrpages;
 565         } else {
 566 #ifdef CONFIG_SHMEM
 567                 struct shmem_inode_info *info = SHMEM_I(inode);
 568                 spin_lock(&info->lock);
 569                 *rss_add += inode->i_mapping->nrpages;
 570                 *swp_add += info->swapped;
 571                 spin_unlock(&info->lock);
 572 #else
 573                 *rss_add += inode->i_mapping->nrpages;
 574 #endif
 575         }
 576 }
 577
 578 /*
 579  * Called with shm_ids.rw_mutex held as a reader
 580  */
 581 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
 582                 unsigned long *swp)
 583 {
 584         int next_id;
 585         int total, in_use;
 586
 587         *rss = 0;
 588         *swp = 0;
 589
 590         in_use = shm_ids(ns).in_use;
 591
 592         for (total = 0, next_id = 0; total < in_use; next_id++) {
 593                 struct kern_ipc_perm *ipc;
 594                 struct shmid_kernel *shp;
 595
 596                 ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
 597                 if (ipc == NULL)
 598                         continue;
 599                 shp = container_of(ipc, struct shmid_kernel, shm_perm);
 600
 601                 shm_add_rss_swap(shp, rss, swp);
 602
 603                 total++;
 604         }
 605 }
 606
 607 /*
 608  * This function handles some shmctl commands which require the rw_mutex
 609  * to be held in write mode.
 610  * NOTE: no locks must be held, the rw_mutex is taken inside this function.
 611  */
 612 static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
 613                        struct shmid_ds __user *buf, int version)
 614 {
 615         struct kern_ipc_perm *ipcp;
 616         struct shmid64_ds shmid64;
 617         struct shmid_kernel *shp;
 618         int err;
 619
 620         if (cmd == IPC_SET) {
 621                 if (copy_shmid_from_user(&shmid64, buf, version))
 622                         return -EFAULT;
 623         }
 624
 625         ipcp = ipcctl_pre_down(&shm_ids(ns), shmid, cmd, &shmid64.shm_perm, 0);
 626         if (IS_ERR(ipcp))
 627                 return PTR_ERR(ipcp);
 628
 629         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 630
 631         err = security_shm_shmctl(shp, cmd);
 632         if (err)
 633                 goto out_unlock;
 634         switch (cmd) {
 635         case IPC_RMID:
 636                 do_shm_rmid(ns, ipcp);
 637                 goto out_up;
 638         case IPC_SET:
 639                 ipc_update_perm(&shmid64.shm_perm, ipcp);
 640                 shp->shm_ctim = get_seconds();
 641                 break;
 642         default:
 643                 err = -EINVAL;
 644         }
 645 out_unlock:
 646         shm_unlock(shp);
 647 out_up:
 648         up_write(&shm_ids(ns).rw_mutex);
 649         return err;
 650 }
 651
 652 SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
 653 {
 654         struct shmid_kernel *shp;
 655         int err, version;
 656         struct ipc_namespace *ns;
 657
 658         if (cmd < 0 || shmid < 0) {
 659                 err = -EINVAL;
 660                 goto out;
 661         }
 662
 663         version = ipc_parse_version(&cmd);
 664         ns = current->nsproxy->ipc_ns;
 665
 666         switch (cmd) { /* replace with proc interface ? */
 667         case IPC_INFO:
 668         {
 669                 struct shminfo64 shminfo;
 670
 671                 err = security_shm_shmctl(NULL, cmd);
 672                 if (err)
 673                         return err;
 674
 675                 memset(&shminfo, 0, sizeof(shminfo));
 676                 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
 677                 shminfo.shmmax = ns->shm_ctlmax;
 678                 shminfo.shmall = ns->shm_ctlall;
 679
 680                 shminfo.shmmin = SHMMIN;
 681                 if(copy_shminfo_to_user (buf, &shminfo, version))
 682                         return -EFAULT;
 683
 684                 down_read(&shm_ids(ns).rw_mutex);
 685                 err = ipc_get_maxid(&shm_ids(ns));
 686                 up_read(&shm_ids(ns).rw_mutex);
 687
 688                 if(err<0)
 689                         err = 0;
 690                 goto out;
 691         }
 692         case SHM_INFO:
 693         {
 694                 struct shm_info shm_info;
 695
 696                 err = security_shm_shmctl(NULL, cmd);
 697                 if (err)
 698                         return err;
 699
 700                 memset(&shm_info, 0, sizeof(shm_info));
 701                 down_read(&shm_ids(ns).rw_mutex);
 702                 shm_info.used_ids = shm_ids(ns).in_use;
 703                 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
 704                 shm_info.shm_tot = ns->shm_tot;
 705                 shm_info.swap_attempts = 0;
 706                 shm_info.swap_successes = 0;
 707                 err = ipc_get_maxid(&shm_ids(ns));
 708                 up_read(&shm_ids(ns).rw_mutex);
 709                 if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {
 710                         err = -EFAULT;
 711                         goto out;
 712                 }
 713
 714                 err = err < 0 ? 0 : err;
 715                 goto out;
 716         }
 717         case SHM_STAT:
 718         case IPC_STAT:
 719         {
 720                 struct shmid64_ds tbuf;
 721                 int result;
 722
 723                 if (cmd == SHM_STAT) {
 724                         shp = shm_lock(ns, shmid);
 725                         if (IS_ERR(shp)) {
 726                                 err = PTR_ERR(shp);
 727                                 goto out;
 728                         }
 729                         result = shp->shm_perm.id;
 730                 } else {
 731                         shp = shm_lock_check(ns, shmid);
 732                         if (IS_ERR(shp)) {
 733                                 err = PTR_ERR(shp);
 734                                 goto out;
 735                         }
 736                         result = 0;
 737                 }
 738                 err = -EACCES;
 739                 if (ipcperms (&shp->shm_perm, S_IRUGO))
 740                         goto out_unlock;
 741                 err = security_shm_shmctl(shp, cmd);
 742                 if (err)
 743                         goto out_unlock;
 744                 memset(&tbuf, 0, sizeof(tbuf));
 745                 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
 746                 tbuf.shm_segsz  = shp->shm_segsz;
 747                 tbuf.shm_atime  = shp->shm_atim;
 748                 tbuf.shm_dtime  = shp->shm_dtim;
 749                 tbuf.shm_ctime  = shp->shm_ctim;
 750                 tbuf.shm_cpid   = shp->shm_cprid;
 751                 tbuf.shm_lpid   = shp->shm_lprid;
 752                 tbuf.shm_nattch = shp->shm_nattch;
 753                 shm_unlock(shp);
 754                 if(copy_shmid_to_user (buf, &tbuf, version))
 755                         err = -EFAULT;
 756                 else
 757                         err = result;
 758                 goto out;
 759         }
 760         case SHM_LOCK:
 761         case SHM_UNLOCK:
 762         {
 763                 struct file *uninitialized_var(shm_file);
 764
 765                 lru_add_drain_all();  /* drain pagevecs to lru lists */
 766
 767                 shp = shm_lock_check(ns, shmid);
 768                 if (IS_ERR(shp)) {
 769                         err = PTR_ERR(shp);
 770                         goto out;
 771                 }
 772
 773                 audit_ipc_obj(&(shp->shm_perm));
 774
 775                 if (!capable(CAP_IPC_LOCK)) {
 776                         uid_t euid = current_euid();
 777                         err = -EPERM;
 778                         if (euid != shp->shm_perm.uid &&
 779                             euid != shp->shm_perm.cuid)
 780                                 goto out_unlock;
 781                         if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK))
 782                                 goto out_unlock;
 783                 }
 784
 785                 err = security_shm_shmctl(shp, cmd);
 786                 if (err)
 787                         goto out_unlock;
 788
 789                 if(cmd==SHM_LOCK) {
 790                         struct user_struct *user = current_user();
 791                         if (!is_file_hugepages(shp->shm_file)) {
 792                                 err = shmem_lock(shp->shm_file, 1, user);
 793                                 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
 794                                         shp->shm_perm.mode |= SHM_LOCKED;
 795                                         shp->mlock_user = user;
 796                                 }
 797                         }
 798                 } else if (!is_file_hugepages(shp->shm_file)) {
 799                         shmem_lock(shp->shm_file, 0, shp->mlock_user);
 800                         shp->shm_perm.mode &= ~SHM_LOCKED;
 801                         shp->mlock_user = NULL;
 802                 }
 803                 shm_unlock(shp);
 804                 goto out;
 805         }
 806         case IPC_RMID:
 807         case IPC_SET:
 808                 err = shmctl_down(ns, shmid, cmd, buf, version);
 809                 return err;
 810         default:
 811                 return -EINVAL;
 812         }
 813
 814 out_unlock:
 815         shm_unlock(shp);
 816 out:
 817         return err;
 818 }
 819
 820 /*
 821  * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
 822  *
 823  * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
 824  * "raddr" thing points to kernel space, and there has to be a wrapper around
 825  * this.
 826  */
 827 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
 828 {
 829         struct shmid_kernel *shp;
 830         unsigned long addr;
 831         unsigned long size;
 832         struct file * file;
 833         int    err;
 834         unsigned long flags;
 835         unsigned long prot;
 836         int acc_mode;
 837         unsigned long user_addr;
 838         struct ipc_namespace *ns;
 839         struct shm_file_data *sfd;
 840         struct path path;
 841         fmode_t f_mode;
 842
 843         err = -EINVAL;
 844         if (shmid < 0)
 845                 goto out;
 846         else if ((addr = (ulong)shmaddr)) {
 847                 if (addr & (SHMLBA-1)) {
 848                         if (shmflg & SHM_RND)
 849                                 addr &= ~(SHMLBA-1);       /* round down */
 850                         else
 851 #ifndef __ARCH_FORCE_SHMLBA
 852                                 if (addr & ~PAGE_MASK)
 853 #endif
 854                                         goto out;
 855                 }
 856                 flags = MAP_SHARED | MAP_FIXED;
 857         } else {
 858                 if ((shmflg & SHM_REMAP))
 859                         goto out;
 860
 861                 flags = MAP_SHARED;
 862         }
 863
 864         if (shmflg & SHM_RDONLY) {
 865                 prot = PROT_READ;
 866                 acc_mode = S_IRUGO;
 867                 f_mode = FMODE_READ;
 868         } else {
 869                 prot = PROT_READ | PROT_WRITE;
 870                 acc_mode = S_IRUGO | S_IWUGO;
 871                 f_mode = FMODE_READ | FMODE_WRITE;
 872         }
 873         if (shmflg & SHM_EXEC) {
 874                 prot |= PROT_EXEC;
 875                 acc_mode |= S_IXUGO;
 876         }
 877
 878         /*
 879          * We cannot rely on the fs check since SYSV IPC does have an
 880          * additional creator id...
 881          */
 882         ns = current->nsproxy->ipc_ns;
 883         shp = shm_lock_check(ns, shmid);
 884         if (IS_ERR(shp)) {
 885                 err = PTR_ERR(shp);
 886                 goto out;
 887         }
 888
 889         err = -EACCES;
 890         if (ipcperms(&shp->shm_perm, acc_mode))
 891                 goto out_unlock;
 892
 893         err = security_shm_shmat(shp, shmaddr, shmflg);
 894         if (err)
 895                 goto out_unlock;
 896
 897         path = shp->shm_file->f_path;
 898         path_get(&path);
 899         shp->shm_nattch++;
 900         size = i_size_read(path.dentry->d_inode);
 901         shm_unlock(shp);
 902
 903         err = -ENOMEM;
 904         sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
 905         if (!sfd)
 906                 goto out_put_dentry;
 907
 908         file = alloc_file(&path, f_mode,
 909                           is_file_hugepages(shp->shm_file) ?
 910                                 &shm_file_operations_huge :
 911                                 &shm_file_operations);
 912         if (!file)
 913                 goto out_free;
 914
 915         file->private_data = sfd;
 916         file->f_mapping = shp->shm_file->f_mapping;
 917         sfd->id = shp->shm_perm.id;
 918         sfd->ns = get_ipc_ns(ns);
 919         sfd->file = shp->shm_file;
 920         sfd->vm_ops = NULL;
 921
 922         down_write(&current->mm->mmap_sem);
 923         if (addr && !(shmflg & SHM_REMAP)) {
 924                 err = -EINVAL;
 925                 if (find_vma_intersection(current->mm, addr, addr + size))
 926                         goto invalid;
 927                 /*
 928                  * If shm segment goes below stack, make sure there is some
 929                  * space left for the stack to grow (at least 4 pages).
 930                  */
 931                 if (addr < current->mm->start_stack &&
 932                     addr > current->mm->start_stack - size - PAGE_SIZE * 5)
 933                         goto invalid;
 934         }
 935
 936         user_addr = do_mmap (file, addr, size, prot, flags, 0);
 937         *raddr = user_addr;
 938         err = 0;
 939         if (IS_ERR_VALUE(user_addr))
 940                 err = (long)user_addr;
 941 invalid:
 942         up_write(&current->mm->mmap_sem);
 943
 944         fput(file);
 945
 946 out_nattch:
 947         down_write(&shm_ids(ns).rw_mutex);
 948         shp = shm_lock(ns, shmid);
 949         BUG_ON(IS_ERR(shp));
 950         shp->shm_nattch--;
 951         if(shp->shm_nattch == 0 &&
 952            shp->shm_perm.mode & SHM_DEST)
 953                 shm_destroy(ns, shp);
 954         else
 955                 shm_unlock(shp);
 956         up_write(&shm_ids(ns).rw_mutex);
 957
 958 out:
 959         return err;
 960
 961 out_unlock:
 962         shm_unlock(shp);
 963         goto out;
 964
 965 out_free:
 966         kfree(sfd);
 967 out_put_dentry:
 968         path_put(&path);
 969         goto out_nattch;
 970 }
 971
 972 SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
 973 {
 974         unsigned long ret;
 975         long err;
 976
 977         err = do_shmat(shmid, shmaddr, shmflg, &ret);
 978         if (err)
 979                 return err;
 980         force_successful_syscall_return();
 981         return (long)ret;
 982 }
 983
 984 /*
 985  * detach and kill segment if marked destroyed.
 986  * The work is done in shm_close.
 987  */
 988 SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
 989 {
 990         struct mm_struct *mm = current->mm;
 991         struct vm_area_struct *vma;
 992         unsigned long addr = (unsigned long)shmaddr;
 993         int retval = -EINVAL;
 994 #ifdef CONFIG_MMU
 995         loff_t size = 0;
 996         struct vm_area_struct *next;
 997 #endif
 998
 999         if (addr & ~PAGE_MASK)
1000                 return retval;
1001
1002         down_write(&mm->mmap_sem);
1003
1004         /*
1005          * This function tries to be smart and unmap shm segments that
1006          * were modified by partial mlock or munmap calls:
1007          * - It first determines the size of the shm segment that should be
1008          *   unmapped: It searches for a vma that is backed by shm and that
1009          *   started at address shmaddr. It records it's size and then unmaps
1010          *   it.
1011          * - Then it unmaps all shm vmas that started at shmaddr and that
1012          *   are within the initially determined size.
1013          * Errors from do_munmap are ignored: the function only fails if
1014          * it's called with invalid parameters or if it's called to unmap
1015          * a part of a vma. Both calls in this function are for full vmas,
1016          * the parameters are directly copied from the vma itself and always
1017          * valid - therefore do_munmap cannot fail. (famous last words?)
1018          */
1019         /*
1020          * If it had been mremap()'d, the starting address would not
1021          * match the usual checks anyway. So assume all vma's are
1022          * above the starting address given.
1023          */
1024         vma = find_vma(mm, addr);
1025
1026 #ifdef CONFIG_MMU
1027         while (vma) {
1028                 next = vma->vm_next;
1029
1030                 /*
1031                  * Check if the starting address would match, i.e. it's
1032                  * a fragment created by mprotect() and/or munmap(), or it
1033                  * otherwise it starts at this address with no hassles.
1034                  */
1035                 if ((vma->vm_ops == &shm_vm_ops) &&
1036                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1037
1038
1039                         size = vma->vm_file->f_path.dentry->d_inode->i_size;
1040                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1041                         /*
1042                          * We discovered the size of the shm segment, so
1043                          * break out of here and fall through to the next
1044                          * loop that uses the size information to stop
1045                          * searching for matching vma's.
1046                          */
1047                         retval = 0;
1048                         vma = next;
1049                         break;
1050                 }
1051                 vma = next;
1052         }
1053
1054         /*
1055          * We need look no further than the maximum address a fragment
1056          * could possibly have landed at. Also cast things to loff_t to
1057          * prevent overflows and make comparisions vs. equal-width types.
1058          */
1059         size = PAGE_ALIGN(size);
1060         while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1061                 next = vma->vm_next;
1062
1063                 /* finding a matching vma now does not alter retval */
1064                 if ((vma->vm_ops == &shm_vm_ops) &&
1065                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1066
1067                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1068                 vma = next;
1069         }
1070
1071 #else /* CONFIG_MMU */
1072         /* under NOMMU conditions, the exact address to be destroyed must be
1073          * given */
1074         retval = -EINVAL;
1075         if (vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
1076                 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1077                 retval = 0;
1078         }
1079
1080 #endif
1081
1082         up_write(&mm->mmap_sem);
1083         return retval;
1084 }
1085
1086 #ifdef CONFIG_PROC_FS
1087 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1088 {
1089         struct shmid_kernel *shp = it;
1090         unsigned long rss = 0, swp = 0;
1091
1092         shm_add_rss_swap(shp, &rss, &swp);
1093
1094 #if BITS_PER_LONG <= 32
1095 #define SIZE_SPEC "%10lu"
1096 #else
1097 #define SIZE_SPEC "%21lu"
1098 #endif
1099
1100         return seq_printf(s,
1101                           "%10d %10d  %4o " SIZE_SPEC " %5u %5u  "
1102                           "%5lu %5u %5u %5u %5u %10lu %10lu %10lu "
1103                           SIZE_SPEC " " SIZE_SPEC "\n",
1104                           shp->shm_perm.key,
1105                           shp->shm_perm.id,
1106                           shp->shm_perm.mode,
1107                           shp->shm_segsz,
1108                           shp->shm_cprid,
1109                           shp->shm_lprid,
1110                           shp->shm_nattch,
1111                           shp->shm_perm.uid,
1112                           shp->shm_perm.gid,
1113                           shp->shm_perm.cuid,
1114                           shp->shm_perm.cgid,
1115                           shp->shm_atim,
1116                           shp->shm_dtim,
1117                           shp->shm_ctim,
1118                           rss * PAGE_SIZE,
1119                           swp * PAGE_SIZE);
1120 }
1121 #endif