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_rmid_forced = 0;
  78         ns->shm_tot = 0;
  79         ipc_init_ids(&shm_ids(ns));
  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         idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
 105 }
 106 #endif
 107
 108 void __init shm_init (void)
 109 {
 110         shm_init_ns(&init_ipc_ns);
 111         ipc_init_proc_interface("sysvipc/shm",
 112 #if BITS_PER_LONG <= 32
 113                                 "       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime        rss       swap\n",
 114 #else
 115                                 "       key      shmid perms                  size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime                   rss                  swap\n",
 116 #endif
 117                                 IPC_SHM_IDS, sysvipc_shm_proc_show);
 118 }
 119
 120 /*
 121  * shm_lock_(check_) routines are called in the paths where the rw_mutex
 122  * is not necessarily held.
 123  */
 124 static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
 125 {
 126         struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
 127
 128         if (IS_ERR(ipcp))
 129                 return (struct shmid_kernel *)ipcp;
 130
 131         return container_of(ipcp, struct shmid_kernel, shm_perm);
 132 }
 133
 134 static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
 135 {
 136         rcu_read_lock();
 137         spin_lock(&ipcp->shm_perm.lock);
 138 }
 139
 140 static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
 141                                                 int id)
 142 {
 143         struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id);
 144
 145         if (IS_ERR(ipcp))
 146                 return (struct shmid_kernel *)ipcp;
 147
 148         return container_of(ipcp, struct shmid_kernel, shm_perm);
 149 }
 150
 151 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
 152 {
 153         ipc_rmid(&shm_ids(ns), &s->shm_perm);
 154 }
 155
 156
 157 /* This is called by fork, once for every shm attach. */
 158 static void shm_open(struct vm_area_struct *vma)
 159 {
 160         struct file *file = vma->vm_file;
 161         struct shm_file_data *sfd = shm_file_data(file);
 162         struct shmid_kernel *shp;
 163
 164         shp = shm_lock(sfd->ns, sfd->id);
 165         BUG_ON(IS_ERR(shp));
 166         shp->shm_atim = get_seconds();
 167         shp->shm_lprid = task_tgid_vnr(current);
 168         shp->shm_nattch++;
 169         shm_unlock(shp);
 170 }
 171
 172 /*
 173  * shm_destroy - free the struct shmid_kernel
 174  *
 175  * @ns: namespace
 176  * @shp: struct to free
 177  *
 178  * It has to be called with shp and shm_ids.rw_mutex (writer) locked,
 179  * but returns with shp unlocked and freed.
 180  */
 181 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
 182 {
 183         ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
 184         shm_rmid(ns, shp);
 185         shm_unlock(shp);
 186         if (!is_file_hugepages(shp->shm_file))
 187                 shmem_lock(shp->shm_file, 0, shp->mlock_user);
 188         else if (shp->mlock_user)
 189                 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
 190                                                 shp->mlock_user);
 191         fput (shp->shm_file);
 192         security_shm_free(shp);
 193         ipc_rcu_putref(shp);
 194 }
 195
 196 /*
 197  * shm_may_destroy - identifies whether shm segment should be destroyed now
 198  *
 199  * Returns true if and only if there are no active users of the segment and
 200  * one of the following is true:
 201  *
 202  * 1) shmctl(id, IPC_RMID, NULL) was called for this shp
 203  *
 204  * 2) sysctl kernel.shm_rmid_forced is set to 1.
 205  */
 206 static bool shm_may_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
 207 {
 208         return (shp->shm_nattch == 0) &&
 209                (ns->shm_rmid_forced ||
 210                 (shp->shm_perm.mode & SHM_DEST));
 211 }
 212
 213 /*
 214  * remove the attach descriptor vma.
 215  * free memory for segment if it is marked destroyed.
 216  * The descriptor has already been removed from the current->mm->mmap list
 217  * and will later be kfree()d.
 218  */
 219 static void shm_close(struct vm_area_struct *vma)
 220 {
 221         struct file * file = vma->vm_file;
 222         struct shm_file_data *sfd = shm_file_data(file);
 223         struct shmid_kernel *shp;
 224         struct ipc_namespace *ns = sfd->ns;
 225
 226         down_write(&shm_ids(ns).rw_mutex);
 227         /* remove from the list of attaches of the shm segment */
 228         shp = shm_lock(ns, sfd->id);
 229         BUG_ON(IS_ERR(shp));
 230         shp->shm_lprid = task_tgid_vnr(current);
 231         shp->shm_dtim = get_seconds();
 232         shp->shm_nattch--;
 233         if (shm_may_destroy(ns, shp))
 234                 shm_destroy(ns, shp);
 235         else
 236                 shm_unlock(shp);
 237         up_write(&shm_ids(ns).rw_mutex);
 238 }
 239
 240 /* Called with ns->shm_ids(ns).rw_mutex locked */
 241 static int shm_try_destroy_current(int id, void *p, void *data)
 242 {
 243         struct ipc_namespace *ns = data;
 244         struct kern_ipc_perm *ipcp = p;
 245         struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 246
 247         if (shp->shm_creator != current)
 248                 return 0;
 249
 250         /*
 251          * Mark it as orphaned to destroy the segment when
 252          * kernel.shm_rmid_forced is changed.
 253          * It is noop if the following shm_may_destroy() returns true.
 254          */
 255         shp->shm_creator = NULL;
 256
 257         /*
 258          * Don't even try to destroy it.  If shm_rmid_forced=0 and IPC_RMID
 259          * is not set, it shouldn't be deleted here.
 260          */
 261         if (!ns->shm_rmid_forced)
 262                 return 0;
 263
 264         if (shm_may_destroy(ns, shp)) {
 265                 shm_lock_by_ptr(shp);
 266                 shm_destroy(ns, shp);
 267         }
 268         return 0;
 269 }
 270
 271 /* Called with ns->shm_ids(ns).rw_mutex locked */
 272 static int shm_try_destroy_orphaned(int id, void *p, void *data)
 273 {
 274         struct ipc_namespace *ns = data;
 275         struct kern_ipc_perm *ipcp = p;
 276         struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 277
 278         /*
 279          * We want to destroy segments without users and with already
 280          * exit'ed originating process.
 281          *
 282          * As shp->* are changed under rw_mutex, it's safe to skip shp locking.
 283          */
 284         if (shp->shm_creator != NULL)
 285                 return 0;
 286
 287         if (shm_may_destroy(ns, shp)) {
 288                 shm_lock_by_ptr(shp);
 289                 shm_destroy(ns, shp);
 290         }
 291         return 0;
 292 }
 293
 294 void shm_destroy_orphaned(struct ipc_namespace *ns)
 295 {
 296         down_write(&shm_ids(ns).rw_mutex);
 297         if (shm_ids(ns).in_use)
 298                 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns);
 299         up_write(&shm_ids(ns).rw_mutex);
 300 }
 301
 302
 303 void exit_shm(struct task_struct *task)
 304 {
 305         struct ipc_namespace *ns = task->nsproxy->ipc_ns;
 306
 307         if (shm_ids(ns).in_use == 0)
 308                 return;
 309
 310         /* Destroy all already created segments, but not mapped yet */
 311         down_write(&shm_ids(ns).rw_mutex);
 312         if (shm_ids(ns).in_use)
 313                 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_current, ns);
 314         up_write(&shm_ids(ns).rw_mutex);
 315 }
 316
 317 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 318 {
 319         struct file *file = vma->vm_file;
 320         struct shm_file_data *sfd = shm_file_data(file);
 321
 322         return sfd->vm_ops->fault(vma, vmf);
 323 }
 324
 325 #ifdef CONFIG_NUMA
 326 static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
 327 {
 328         struct file *file = vma->vm_file;
 329         struct shm_file_data *sfd = shm_file_data(file);
 330         int err = 0;
 331         if (sfd->vm_ops->set_policy)
 332                 err = sfd->vm_ops->set_policy(vma, new);
 333         return err;
 334 }
 335
 336 static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
 337                                         unsigned long addr)
 338 {
 339         struct file *file = vma->vm_file;
 340         struct shm_file_data *sfd = shm_file_data(file);
 341         struct mempolicy *pol = NULL;
 342
 343         if (sfd->vm_ops->get_policy)
 344                 pol = sfd->vm_ops->get_policy(vma, addr);
 345         else if (vma->vm_policy)
 346                 pol = vma->vm_policy;
 347
 348         return pol;
 349 }
 350 #endif
 351
 352 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
 353 {
 354         struct shm_file_data *sfd = shm_file_data(file);
 355         int ret;
 356
 357         ret = sfd->file->f_op->mmap(sfd->file, vma);
 358         if (ret != 0)
 359                 return ret;
 360         sfd->vm_ops = vma->vm_ops;
 361 #ifdef CONFIG_MMU
 362         BUG_ON(!sfd->vm_ops->fault);
 363 #endif
 364         vma->vm_ops = &shm_vm_ops;
 365         shm_open(vma);
 366
 367         return ret;
 368 }
 369
 370 static int shm_release(struct inode *ino, struct file *file)
 371 {
 372         struct shm_file_data *sfd = shm_file_data(file);
 373
 374         put_ipc_ns(sfd->ns);
 375         shm_file_data(file) = NULL;
 376         kfree(sfd);
 377         return 0;
 378 }
 379
 380 static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
 381 {
 382         struct shm_file_data *sfd = shm_file_data(file);
 383
 384         if (!sfd->file->f_op->fsync)
 385                 return -EINVAL;
 386         return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
 387 }
 388
 389 static unsigned long shm_get_unmapped_area(struct file *file,
 390         unsigned long addr, unsigned long len, unsigned long pgoff,
 391         unsigned long flags)
 392 {
 393         struct shm_file_data *sfd = shm_file_data(file);
 394         return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
 395                                                 pgoff, flags);
 396 }
 397
 398 static const struct file_operations shm_file_operations = {
 399         .mmap           = shm_mmap,
 400         .fsync          = shm_fsync,
 401         .release        = shm_release,
 402 #ifndef CONFIG_MMU
 403         .get_unmapped_area      = shm_get_unmapped_area,
 404 #endif
 405         .llseek         = noop_llseek,
 406 };
 407
 408 static const struct file_operations shm_file_operations_huge = {
 409         .mmap           = shm_mmap,
 410         .fsync          = shm_fsync,
 411         .release        = shm_release,
 412         .get_unmapped_area      = shm_get_unmapped_area,
 413         .llseek         = noop_llseek,
 414 };
 415
 416 int is_file_shm_hugepages(struct file *file)
 417 {
 418         return file->f_op == &shm_file_operations_huge;
 419 }
 420
 421 static const struct vm_operations_struct shm_vm_ops = {
 422         .open   = shm_open,     /* callback for a new vm-area open */
 423         .close  = shm_close,    /* callback for when the vm-area is released */
 424         .fault  = shm_fault,
 425 #if defined(CONFIG_NUMA)
 426         .set_policy = shm_set_policy,
 427         .get_policy = shm_get_policy,
 428 #endif
 429 };
 430
 431 /**
 432  * newseg - Create a new shared memory segment
 433  * @ns: namespace
 434  * @params: ptr to the structure that contains key, size and shmflg
 435  *
 436  * Called with shm_ids.rw_mutex held as a writer.
 437  */
 438
 439 static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
 440 {
 441         key_t key = params->key;
 442         int shmflg = params->flg;
 443         size_t size = params->u.size;
 444         int error;
 445         struct shmid_kernel *shp;
 446         int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
 447         struct file * file;
 448         char name[13];
 449         int id;
 450         vm_flags_t acctflag = 0;
 451
 452         if (size < SHMMIN || size > ns->shm_ctlmax)
 453                 return -EINVAL;
 454
 455         if (ns->shm_tot + numpages > ns->shm_ctlall)
 456                 return -ENOSPC;
 457
 458         shp = ipc_rcu_alloc(sizeof(*shp));
 459         if (!shp)
 460                 return -ENOMEM;
 461
 462         shp->shm_perm.key = key;
 463         shp->shm_perm.mode = (shmflg & S_IRWXUGO);
 464         shp->mlock_user = NULL;
 465
 466         shp->shm_perm.security = NULL;
 467         error = security_shm_alloc(shp);
 468         if (error) {
 469                 ipc_rcu_putref(shp);
 470                 return error;
 471         }
 472
 473         sprintf (name, "SYSV%08x", key);
 474         if (shmflg & SHM_HUGETLB) {
 475                 /* hugetlb_file_setup applies strict accounting */
 476                 if (shmflg & SHM_NORESERVE)
 477                         acctflag = VM_NORESERVE;
 478                 file = hugetlb_file_setup(name, size, acctflag,
 479                                         &shp->mlock_user, HUGETLB_SHMFS_INODE);
 480         } else {
 481                 /*
 482                  * Do not allow no accounting for OVERCOMMIT_NEVER, even
 483                  * if it's asked for.
 484                  */
 485                 if  ((shmflg & SHM_NORESERVE) &&
 486                                 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
 487                         acctflag = VM_NORESERVE;
 488                 file = shmem_file_setup(name, size, acctflag);
 489         }
 490         error = PTR_ERR(file);
 491         if (IS_ERR(file))
 492                 goto no_file;
 493
 494         id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
 495         if (id < 0) {
 496                 error = id;
 497                 goto no_id;
 498         }
 499
 500         shp->shm_cprid = task_tgid_vnr(current);
 501         shp->shm_lprid = 0;
 502         shp->shm_atim = shp->shm_dtim = 0;
 503         shp->shm_ctim = get_seconds();
 504         shp->shm_segsz = size;
 505         shp->shm_nattch = 0;
 506         shp->shm_file = file;
 507         shp->shm_creator = current;
 508         /*
 509          * shmid gets reported as "inode#" in /proc/pid/maps.
 510          * proc-ps tools use this. Changing this will break them.
 511          */
 512         file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
 513
 514         ns->shm_tot += numpages;
 515         error = shp->shm_perm.id;
 516         shm_unlock(shp);
 517         return error;
 518
 519 no_id:
 520         if (is_file_hugepages(file) && shp->mlock_user)
 521                 user_shm_unlock(size, shp->mlock_user);
 522         fput(file);
 523 no_file:
 524         security_shm_free(shp);
 525         ipc_rcu_putref(shp);
 526         return error;
 527 }
 528
 529 /*
 530  * Called with shm_ids.rw_mutex and ipcp locked.
 531  */
 532 static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
 533 {
 534         struct shmid_kernel *shp;
 535
 536         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 537         return security_shm_associate(shp, shmflg);
 538 }
 539
 540 /*
 541  * Called with shm_ids.rw_mutex and ipcp locked.
 542  */
 543 static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
 544                                 struct ipc_params *params)
 545 {
 546         struct shmid_kernel *shp;
 547
 548         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 549         if (shp->shm_segsz < params->u.size)
 550                 return -EINVAL;
 551
 552         return 0;
 553 }
 554
 555 SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
 556 {
 557         struct ipc_namespace *ns;
 558         struct ipc_ops shm_ops;
 559         struct ipc_params shm_params;
 560
 561         ns = current->nsproxy->ipc_ns;
 562
 563         shm_ops.getnew = newseg;
 564         shm_ops.associate = shm_security;
 565         shm_ops.more_checks = shm_more_checks;
 566
 567         shm_params.key = key;
 568         shm_params.flg = shmflg;
 569         shm_params.u.size = size;
 570
 571         return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
 572 }
 573
 574 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
 575 {
 576         switch(version) {
 577         case IPC_64:
 578                 return copy_to_user(buf, in, sizeof(*in));
 579         case IPC_OLD:
 580             {
 581                 struct shmid_ds out;
 582
 583                 memset(&out, 0, sizeof(out));
 584                 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
 585                 out.shm_segsz   = in->shm_segsz;
 586                 out.shm_atime   = in->shm_atime;
 587                 out.shm_dtime   = in->shm_dtime;
 588                 out.shm_ctime   = in->shm_ctime;
 589                 out.shm_cpid    = in->shm_cpid;
 590                 out.shm_lpid    = in->shm_lpid;
 591                 out.shm_nattch  = in->shm_nattch;
 592
 593                 return copy_to_user(buf, &out, sizeof(out));
 594             }
 595         default:
 596                 return -EINVAL;
 597         }
 598 }
 599
 600 static inline unsigned long
 601 copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
 602 {
 603         switch(version) {
 604         case IPC_64:
 605                 if (copy_from_user(out, buf, sizeof(*out)))
 606                         return -EFAULT;
 607                 return 0;
 608         case IPC_OLD:
 609             {
 610                 struct shmid_ds tbuf_old;
 611
 612                 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
 613                         return -EFAULT;
 614
 615                 out->shm_perm.uid       = tbuf_old.shm_perm.uid;
 616                 out->shm_perm.gid       = tbuf_old.shm_perm.gid;
 617                 out->shm_perm.mode      = tbuf_old.shm_perm.mode;
 618
 619                 return 0;
 620             }
 621         default:
 622                 return -EINVAL;
 623         }
 624 }
 625
 626 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
 627 {
 628         switch(version) {
 629         case IPC_64:
 630                 return copy_to_user(buf, in, sizeof(*in));
 631         case IPC_OLD:
 632             {
 633                 struct shminfo out;
 634
 635                 if(in->shmmax > INT_MAX)
 636                         out.shmmax = INT_MAX;
 637                 else
 638                         out.shmmax = (int)in->shmmax;
 639
 640                 out.shmmin      = in->shmmin;
 641                 out.shmmni      = in->shmmni;
 642                 out.shmseg      = in->shmseg;
 643                 out.shmall      = in->shmall;
 644
 645                 return copy_to_user(buf, &out, sizeof(out));
 646             }
 647         default:
 648                 return -EINVAL;
 649         }
 650 }
 651
 652 /*
 653  * Calculate and add used RSS and swap pages of a shm.
 654  * Called with shm_ids.rw_mutex held as a reader
 655  */
 656 static void shm_add_rss_swap(struct shmid_kernel *shp,
 657         unsigned long *rss_add, unsigned long *swp_add)
 658 {
 659         struct inode *inode;
 660
 661         inode = shp->shm_file->f_path.dentry->d_inode;
 662
 663         if (is_file_hugepages(shp->shm_file)) {
 664                 struct address_space *mapping = inode->i_mapping;
 665                 struct hstate *h = hstate_file(shp->shm_file);
 666                 *rss_add += pages_per_huge_page(h) * mapping->nrpages;
 667         } else {
 668 #ifdef CONFIG_SHMEM
 669                 struct shmem_inode_info *info = SHMEM_I(inode);
 670                 spin_lock(&info->lock);
 671                 *rss_add += inode->i_mapping->nrpages;
 672                 *swp_add += info->swapped;
 673                 spin_unlock(&info->lock);
 674 #else
 675                 *rss_add += inode->i_mapping->nrpages;
 676 #endif
 677         }
 678 }
 679
 680 /*
 681  * Called with shm_ids.rw_mutex held as a reader
 682  */
 683 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
 684                 unsigned long *swp)
 685 {
 686         int next_id;
 687         int total, in_use;
 688
 689         *rss = 0;
 690         *swp = 0;
 691
 692         in_use = shm_ids(ns).in_use;
 693
 694         for (total = 0, next_id = 0; total < in_use; next_id++) {
 695                 struct kern_ipc_perm *ipc;
 696                 struct shmid_kernel *shp;
 697
 698                 ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
 699                 if (ipc == NULL)
 700                         continue;
 701                 shp = container_of(ipc, struct shmid_kernel, shm_perm);
 702
 703                 shm_add_rss_swap(shp, rss, swp);
 704
 705                 total++;
 706         }
 707 }
 708
 709 /*
 710  * This function handles some shmctl commands which require the rw_mutex
 711  * to be held in write mode.
 712  * NOTE: no locks must be held, the rw_mutex is taken inside this function.
 713  */
 714 static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
 715                        struct shmid_ds __user *buf, int version)
 716 {
 717         struct kern_ipc_perm *ipcp;
 718         struct shmid64_ds shmid64;
 719         struct shmid_kernel *shp;
 720         int err;
 721
 722         if (cmd == IPC_SET) {
 723                 if (copy_shmid_from_user(&shmid64, buf, version))
 724                         return -EFAULT;
 725         }
 726
 727         ipcp = ipcctl_pre_down(ns, &shm_ids(ns), shmid, cmd,
 728                                &shmid64.shm_perm, 0);
 729         if (IS_ERR(ipcp))
 730                 return PTR_ERR(ipcp);
 731
 732         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 733
 734         err = security_shm_shmctl(shp, cmd);
 735         if (err)
 736                 goto out_unlock;
 737         switch (cmd) {
 738         case IPC_RMID:
 739                 do_shm_rmid(ns, ipcp);
 740                 goto out_up;
 741         case IPC_SET:
 742                 ipc_update_perm(&shmid64.shm_perm, ipcp);
 743                 shp->shm_ctim = get_seconds();
 744                 break;
 745         default:
 746                 err = -EINVAL;
 747         }
 748 out_unlock:
 749         shm_unlock(shp);
 750 out_up:
 751         up_write(&shm_ids(ns).rw_mutex);
 752         return err;
 753 }
 754
 755 SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
 756 {
 757         struct shmid_kernel *shp;
 758         int err, version;
 759         struct ipc_namespace *ns;
 760
 761         if (cmd < 0 || shmid < 0) {
 762                 err = -EINVAL;
 763                 goto out;
 764         }
 765
 766         version = ipc_parse_version(&cmd);
 767         ns = current->nsproxy->ipc_ns;
 768
 769         switch (cmd) { /* replace with proc interface ? */
 770         case IPC_INFO:
 771         {
 772                 struct shminfo64 shminfo;
 773
 774                 err = security_shm_shmctl(NULL, cmd);
 775                 if (err)
 776                         return err;
 777
 778                 memset(&shminfo, 0, sizeof(shminfo));
 779                 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
 780                 shminfo.shmmax = ns->shm_ctlmax;
 781                 shminfo.shmall = ns->shm_ctlall;
 782
 783                 shminfo.shmmin = SHMMIN;
 784                 if(copy_shminfo_to_user (buf, &shminfo, version))
 785                         return -EFAULT;
 786
 787                 down_read(&shm_ids(ns).rw_mutex);
 788                 err = ipc_get_maxid(&shm_ids(ns));
 789                 up_read(&shm_ids(ns).rw_mutex);
 790
 791                 if(err<0)
 792                         err = 0;
 793                 goto out;
 794         }
 795         case SHM_INFO:
 796         {
 797                 struct shm_info shm_info;
 798
 799                 err = security_shm_shmctl(NULL, cmd);
 800                 if (err)
 801                         return err;
 802
 803                 memset(&shm_info, 0, sizeof(shm_info));
 804                 down_read(&shm_ids(ns).rw_mutex);
 805                 shm_info.used_ids = shm_ids(ns).in_use;
 806                 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
 807                 shm_info.shm_tot = ns->shm_tot;
 808                 shm_info.swap_attempts = 0;
 809                 shm_info.swap_successes = 0;
 810                 err = ipc_get_maxid(&shm_ids(ns));
 811                 up_read(&shm_ids(ns).rw_mutex);
 812                 if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {
 813                         err = -EFAULT;
 814                         goto out;
 815                 }
 816
 817                 err = err < 0 ? 0 : err;
 818                 goto out;
 819         }
 820         case SHM_STAT:
 821         case IPC_STAT:
 822         {
 823                 struct shmid64_ds tbuf;
 824                 int result;
 825
 826                 if (cmd == SHM_STAT) {
 827                         shp = shm_lock(ns, shmid);
 828                         if (IS_ERR(shp)) {
 829                                 err = PTR_ERR(shp);
 830                                 goto out;
 831                         }
 832                         result = shp->shm_perm.id;
 833                 } else {
 834                         shp = shm_lock_check(ns, shmid);
 835                         if (IS_ERR(shp)) {
 836                                 err = PTR_ERR(shp);
 837                                 goto out;
 838                         }
 839                         result = 0;
 840                 }
 841                 err = -EACCES;
 842                 if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
 843                         goto out_unlock;
 844                 err = security_shm_shmctl(shp, cmd);
 845                 if (err)
 846                         goto out_unlock;
 847                 memset(&tbuf, 0, sizeof(tbuf));
 848                 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
 849                 tbuf.shm_segsz  = shp->shm_segsz;
 850                 tbuf.shm_atime  = shp->shm_atim;
 851                 tbuf.shm_dtime  = shp->shm_dtim;
 852                 tbuf.shm_ctime  = shp->shm_ctim;
 853                 tbuf.shm_cpid   = shp->shm_cprid;
 854                 tbuf.shm_lpid   = shp->shm_lprid;
 855                 tbuf.shm_nattch = shp->shm_nattch;
 856                 shm_unlock(shp);
 857                 if(copy_shmid_to_user (buf, &tbuf, version))
 858                         err = -EFAULT;
 859                 else
 860                         err = result;
 861                 goto out;
 862         }
 863         case SHM_LOCK:
 864         case SHM_UNLOCK:
 865         {
 866                 struct file *uninitialized_var(shm_file);
 867
 868                 lru_add_drain_all();  /* drain pagevecs to lru lists */
 869
 870                 shp = shm_lock_check(ns, shmid);
 871                 if (IS_ERR(shp)) {
 872                         err = PTR_ERR(shp);
 873                         goto out;
 874                 }
 875
 876                 audit_ipc_obj(&(shp->shm_perm));
 877
 878                 if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
 879                         uid_t euid = current_euid();
 880                         err = -EPERM;
 881                         if (euid != shp->shm_perm.uid &&
 882                             euid != shp->shm_perm.cuid)
 883                                 goto out_unlock;
 884                         if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK))
 885                                 goto out_unlock;
 886                 }
 887
 888                 err = security_shm_shmctl(shp, cmd);
 889                 if (err)
 890                         goto out_unlock;
 891
 892                 if(cmd==SHM_LOCK) {
 893                         struct user_struct *user = current_user();
 894                         if (!is_file_hugepages(shp->shm_file)) {
 895                                 err = shmem_lock(shp->shm_file, 1, user);
 896                                 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
 897                                         shp->shm_perm.mode |= SHM_LOCKED;
 898                                         shp->mlock_user = user;
 899                                 }
 900                         }
 901                 } else if (!is_file_hugepages(shp->shm_file)) {
 902                         shmem_lock(shp->shm_file, 0, shp->mlock_user);
 903                         shp->shm_perm.mode &= ~SHM_LOCKED;
 904                         shp->mlock_user = NULL;
 905                 }
 906                 shm_unlock(shp);
 907                 goto out;
 908         }
 909         case IPC_RMID:
 910         case IPC_SET:
 911                 err = shmctl_down(ns, shmid, cmd, buf, version);
 912                 return err;
 913         default:
 914                 return -EINVAL;
 915         }
 916
 917 out_unlock:
 918         shm_unlock(shp);
 919 out:
 920         return err;
 921 }
 922
 923 /*
 924  * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
 925  *
 926  * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
 927  * "raddr" thing points to kernel space, and there has to be a wrapper around
 928  * this.
 929  */
 930 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
 931 {
 932         struct shmid_kernel *shp;
 933         unsigned long addr;
 934         unsigned long size;
 935         struct file * file;
 936         int    err;
 937         unsigned long flags;
 938         unsigned long prot;
 939         int acc_mode;
 940         unsigned long user_addr;
 941         struct ipc_namespace *ns;
 942         struct shm_file_data *sfd;
 943         struct path path;
 944         fmode_t f_mode;
 945
 946         err = -EINVAL;
 947         if (shmid < 0)
 948                 goto out;
 949         else if ((addr = (ulong)shmaddr)) {
 950                 if (addr & (SHMLBA-1)) {
 951                         if (shmflg & SHM_RND)
 952                                 addr &= ~(SHMLBA-1);       /* round down */
 953                         else
 954 #ifndef __ARCH_FORCE_SHMLBA
 955                                 if (addr & ~PAGE_MASK)
 956 #endif
 957                                         goto out;
 958                 }
 959                 flags = MAP_SHARED | MAP_FIXED;
 960         } else {
 961                 if ((shmflg & SHM_REMAP))
 962                         goto out;
 963
 964                 flags = MAP_SHARED;
 965         }
 966
 967         if (shmflg & SHM_RDONLY) {
 968                 prot = PROT_READ;
 969                 acc_mode = S_IRUGO;
 970                 f_mode = FMODE_READ;
 971         } else {
 972                 prot = PROT_READ | PROT_WRITE;
 973                 acc_mode = S_IRUGO | S_IWUGO;
 974                 f_mode = FMODE_READ | FMODE_WRITE;
 975         }
 976         if (shmflg & SHM_EXEC) {
 977                 prot |= PROT_EXEC;
 978                 acc_mode |= S_IXUGO;
 979         }
 980
 981         /*
 982          * We cannot rely on the fs check since SYSV IPC does have an
 983          * additional creator id...
 984          */
 985         ns = current->nsproxy->ipc_ns;
 986         shp = shm_lock_check(ns, shmid);
 987         if (IS_ERR(shp)) {
 988                 err = PTR_ERR(shp);
 989                 goto out;
 990         }
 991
 992         err = -EACCES;
 993         if (ipcperms(ns, &shp->shm_perm, acc_mode))
 994                 goto out_unlock;
 995
 996         err = security_shm_shmat(shp, shmaddr, shmflg);
 997         if (err)
 998                 goto out_unlock;
 999
1000         path = shp->shm_file->f_path;
1001         path_get(&path);
1002         shp->shm_nattch++;
1003         size = i_size_read(path.dentry->d_inode);
1004         shm_unlock(shp);
1005
1006         err = -ENOMEM;
1007         sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
1008         if (!sfd)
1009                 goto out_put_dentry;
1010
1011         file = alloc_file(&path, f_mode,
1012                           is_file_hugepages(shp->shm_file) ?
1013                                 &shm_file_operations_huge :
1014                                 &shm_file_operations);
1015         if (!file)
1016                 goto out_free;
1017
1018         file->private_data = sfd;
1019         file->f_mapping = shp->shm_file->f_mapping;
1020         sfd->id = shp->shm_perm.id;
1021         sfd->ns = get_ipc_ns(ns);
1022         sfd->file = shp->shm_file;
1023         sfd->vm_ops = NULL;
1024
1025         down_write(&current->mm->mmap_sem);
1026         if (addr && !(shmflg & SHM_REMAP)) {
1027                 err = -EINVAL;
1028                 if (find_vma_intersection(current->mm, addr, addr + size))
1029                         goto invalid;
1030                 /*
1031                  * If shm segment goes below stack, make sure there is some
1032                  * space left for the stack to grow (at least 4 pages).
1033                  */
1034                 if (addr < current->mm->start_stack &&
1035                     addr > current->mm->start_stack - size - PAGE_SIZE * 5)
1036                         goto invalid;
1037         }
1038
1039         user_addr = do_mmap (file, addr, size, prot, flags, 0);
1040         *raddr = user_addr;
1041         err = 0;
1042         if (IS_ERR_VALUE(user_addr))
1043                 err = (long)user_addr;
1044 invalid:
1045         up_write(&current->mm->mmap_sem);
1046
1047         fput(file);
1048
1049 out_nattch:
1050         down_write(&shm_ids(ns).rw_mutex);
1051         shp = shm_lock(ns, shmid);
1052         BUG_ON(IS_ERR(shp));
1053         shp->shm_nattch--;
1054         if (shm_may_destroy(ns, shp))
1055                 shm_destroy(ns, shp);
1056         else
1057                 shm_unlock(shp);
1058         up_write(&shm_ids(ns).rw_mutex);
1059
1060 out:
1061         return err;
1062
1063 out_unlock:
1064         shm_unlock(shp);
1065         goto out;
1066
1067 out_free:
1068         kfree(sfd);
1069 out_put_dentry:
1070         path_put(&path);
1071         goto out_nattch;
1072 }
1073
1074 SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
1075 {
1076         unsigned long ret;
1077         long err;
1078
1079         err = do_shmat(shmid, shmaddr, shmflg, &ret);
1080         if (err)
1081                 return err;
1082         force_successful_syscall_return();
1083         return (long)ret;
1084 }
1085
1086 /*
1087  * detach and kill segment if marked destroyed.
1088  * The work is done in shm_close.
1089  */
1090 SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
1091 {
1092         struct mm_struct *mm = current->mm;
1093         struct vm_area_struct *vma;
1094         unsigned long addr = (unsigned long)shmaddr;
1095         int retval = -EINVAL;
1096 #ifdef CONFIG_MMU
1097         loff_t size = 0;
1098         struct vm_area_struct *next;
1099 #endif
1100
1101         if (addr & ~PAGE_MASK)
1102                 return retval;
1103
1104         down_write(&mm->mmap_sem);
1105
1106         /*
1107          * This function tries to be smart and unmap shm segments that
1108          * were modified by partial mlock or munmap calls:
1109          * - It first determines the size of the shm segment that should be
1110          *   unmapped: It searches for a vma that is backed by shm and that
1111          *   started at address shmaddr. It records it's size and then unmaps
1112          *   it.
1113          * - Then it unmaps all shm vmas that started at shmaddr and that
1114          *   are within the initially determined size.
1115          * Errors from do_munmap are ignored: the function only fails if
1116          * it's called with invalid parameters or if it's called to unmap
1117          * a part of a vma. Both calls in this function are for full vmas,
1118          * the parameters are directly copied from the vma itself and always
1119          * valid - therefore do_munmap cannot fail. (famous last words?)
1120          */
1121         /*
1122          * If it had been mremap()'d, the starting address would not
1123          * match the usual checks anyway. So assume all vma's are
1124          * above the starting address given.
1125          */
1126         vma = find_vma(mm, addr);
1127
1128 #ifdef CONFIG_MMU
1129         while (vma) {
1130                 next = vma->vm_next;
1131
1132                 /*
1133                  * Check if the starting address would match, i.e. it's
1134                  * a fragment created by mprotect() and/or munmap(), or it
1135                  * otherwise it starts at this address with no hassles.
1136                  */
1137                 if ((vma->vm_ops == &shm_vm_ops) &&
1138                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1139
1140
1141                         size = vma->vm_file->f_path.dentry->d_inode->i_size;
1142                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1143                         /*
1144                          * We discovered the size of the shm segment, so
1145                          * break out of here and fall through to the next
1146                          * loop that uses the size information to stop
1147                          * searching for matching vma's.
1148                          */
1149                         retval = 0;
1150                         vma = next;
1151                         break;
1152                 }
1153                 vma = next;
1154         }
1155
1156         /*
1157          * We need look no further than the maximum address a fragment
1158          * could possibly have landed at. Also cast things to loff_t to
1159          * prevent overflows and make comparisons vs. equal-width types.
1160          */
1161         size = PAGE_ALIGN(size);
1162         while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1163                 next = vma->vm_next;
1164
1165                 /* finding a matching vma now does not alter retval */
1166                 if ((vma->vm_ops == &shm_vm_ops) &&
1167                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1168
1169                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1170                 vma = next;
1171         }
1172
1173 #else /* CONFIG_MMU */
1174         /* under NOMMU conditions, the exact address to be destroyed must be
1175          * given */
1176         retval = -EINVAL;
1177         if (vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
1178                 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1179                 retval = 0;
1180         }
1181
1182 #endif
1183
1184         up_write(&mm->mmap_sem);
1185         return retval;
1186 }
1187
1188 #ifdef CONFIG_PROC_FS
1189 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1190 {
1191         struct shmid_kernel *shp = it;
1192         unsigned long rss = 0, swp = 0;
1193
1194         shm_add_rss_swap(shp, &rss, &swp);
1195
1196 #if BITS_PER_LONG <= 32
1197 #define SIZE_SPEC "%10lu"
1198 #else
1199 #define SIZE_SPEC "%21lu"
1200 #endif
1201
1202         return seq_printf(s,
1203                           "%10d %10d  %4o " SIZE_SPEC " %5u %5u  "
1204                           "%5lu %5u %5u %5u %5u %10lu %10lu %10lu "
1205                           SIZE_SPEC " " SIZE_SPEC "\n",
1206                           shp->shm_perm.key,
1207                           shp->shm_perm.id,
1208                           shp->shm_perm.mode,
1209                           shp->shm_segsz,
1210                           shp->shm_cprid,
1211                           shp->shm_lprid,
1212                           shp->shm_nattch,
1213                           shp->shm_perm.uid,
1214                           shp->shm_perm.gid,
1215                           shp->shm_perm.cuid,
1216                           shp->shm_perm.cgid,
1217                           shp->shm_atim,
1218                           shp->shm_dtim,
1219                           shp->shm_ctim,
1220                           rss * PAGE_SIZE,
1221                           swp * PAGE_SIZE);
1222 }
1223 #endif