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 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                 mpol_get(pol);  /* get_vma_policy() expects this */
 277         } else
 278                 pol = current->mempolicy;
 279         return pol;
 280 }
 281 #endif
 282
 283 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
 284 {
 285         struct shm_file_data *sfd = shm_file_data(file);
 286         int ret;
 287
 288         ret = sfd->file->f_op->mmap(sfd->file, vma);
 289         if (ret != 0)
 290                 return ret;
 291         sfd->vm_ops = vma->vm_ops;
 292 #ifdef CONFIG_MMU
 293         BUG_ON(!sfd->vm_ops->fault);
 294 #endif
 295         vma->vm_ops = &shm_vm_ops;
 296         shm_open(vma);
 297
 298         return ret;
 299 }
 300
 301 static int shm_release(struct inode *ino, struct file *file)
 302 {
 303         struct shm_file_data *sfd = shm_file_data(file);
 304
 305         put_ipc_ns(sfd->ns);
 306         shm_file_data(file) = NULL;
 307         kfree(sfd);
 308         return 0;
 309 }
 310
 311 static int shm_fsync(struct file *file, struct dentry *dentry, int datasync)
 312 {
 313         int (*fsync) (struct file *, struct dentry *, int datasync);
 314         struct shm_file_data *sfd = shm_file_data(file);
 315         int ret = -EINVAL;
 316
 317         fsync = sfd->file->f_op->fsync;
 318         if (fsync)
 319                 ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync);
 320         return ret;
 321 }
 322
 323 static unsigned long shm_get_unmapped_area(struct file *file,
 324         unsigned long addr, unsigned long len, unsigned long pgoff,
 325         unsigned long flags)
 326 {
 327         struct shm_file_data *sfd = shm_file_data(file);
 328         return get_unmapped_area(sfd->file, addr, len, pgoff, flags);
 329 }
 330
 331 int is_file_shm_hugepages(struct file *file)
 332 {
 333         int ret = 0;
 334
 335         if (file->f_op == &shm_file_operations) {
 336                 struct shm_file_data *sfd;
 337                 sfd = shm_file_data(file);
 338                 ret = is_file_hugepages(sfd->file);
 339         }
 340         return ret;
 341 }
 342
 343 static const struct file_operations shm_file_operations = {
 344         .mmap           = shm_mmap,
 345         .fsync          = shm_fsync,
 346         .release        = shm_release,
 347         .get_unmapped_area      = shm_get_unmapped_area,
 348 };
 349
 350 static struct vm_operations_struct shm_vm_ops = {
 351         .open   = shm_open,     /* callback for a new vm-area open */
 352         .close  = shm_close,    /* callback for when the vm-area is released */
 353         .fault  = shm_fault,
 354 #if defined(CONFIG_NUMA)
 355         .set_policy = shm_set_policy,
 356         .get_policy = shm_get_policy,
 357 #endif
 358 };
 359
 360 /**
 361  * newseg - Create a new shared memory segment
 362  * @ns: namespace
 363  * @params: ptr to the structure that contains key, size and shmflg
 364  *
 365  * Called with shm_ids.rw_mutex held as a writer.
 366  */
 367
 368 static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
 369 {
 370         key_t key = params->key;
 371         int shmflg = params->flg;
 372         size_t size = params->u.size;
 373         int error;
 374         struct shmid_kernel *shp;
 375         int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
 376         struct file * file;
 377         char name[13];
 378         int id;
 379
 380         if (size < SHMMIN || size > ns->shm_ctlmax)
 381                 return -EINVAL;
 382
 383         if (ns->shm_tot + numpages > ns->shm_ctlall)
 384                 return -ENOSPC;
 385
 386         shp = ipc_rcu_alloc(sizeof(*shp));
 387         if (!shp)
 388                 return -ENOMEM;
 389
 390         shp->shm_perm.key = key;
 391         shp->shm_perm.mode = (shmflg & S_IRWXUGO);
 392         shp->mlock_user = NULL;
 393
 394         shp->shm_perm.security = NULL;
 395         error = security_shm_alloc(shp);
 396         if (error) {
 397                 ipc_rcu_putref(shp);
 398                 return error;
 399         }
 400
 401         sprintf (name, "SYSV%08x", key);
 402         if (shmflg & SHM_HUGETLB) {
 403                 /* hugetlb_file_setup takes care of mlock user accounting */
 404                 file = hugetlb_file_setup(name, size);
 405                 shp->mlock_user = current->user;
 406         } else {
 407                 int acctflag = VM_ACCOUNT;
 408                 /*
 409                  * Do not allow no accounting for OVERCOMMIT_NEVER, even
 410                  * if it's asked for.
 411                  */
 412                 if  ((shmflg & SHM_NORESERVE) &&
 413                                 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
 414                         acctflag = 0;
 415                 file = shmem_file_setup(name, size, acctflag);
 416         }
 417         error = PTR_ERR(file);
 418         if (IS_ERR(file))
 419                 goto no_file;
 420
 421         id = shm_addid(ns, shp);
 422         if (id < 0) {
 423                 error = id;
 424                 goto no_id;
 425         }
 426
 427         shp->shm_cprid = task_tgid_vnr(current);
 428         shp->shm_lprid = 0;
 429         shp->shm_atim = shp->shm_dtim = 0;
 430         shp->shm_ctim = get_seconds();
 431         shp->shm_segsz = size;
 432         shp->shm_nattch = 0;
 433         shp->shm_perm.id = shm_buildid(id, shp->shm_perm.seq);
 434         shp->shm_file = file;
 435         /*
 436          * shmid gets reported as "inode#" in /proc/pid/maps.
 437          * proc-ps tools use this. Changing this will break them.
 438          */
 439         file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
 440
 441         ns->shm_tot += numpages;
 442         error = shp->shm_perm.id;
 443         shm_unlock(shp);
 444         return error;
 445
 446 no_id:
 447         fput(file);
 448 no_file:
 449         security_shm_free(shp);
 450         ipc_rcu_putref(shp);
 451         return error;
 452 }
 453
 454 /*
 455  * Called with shm_ids.rw_mutex and ipcp locked.
 456  */
 457 static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
 458 {
 459         struct shmid_kernel *shp;
 460
 461         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 462         return security_shm_associate(shp, shmflg);
 463 }
 464
 465 /*
 466  * Called with shm_ids.rw_mutex and ipcp locked.
 467  */
 468 static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
 469                                 struct ipc_params *params)
 470 {
 471         struct shmid_kernel *shp;
 472
 473         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 474         if (shp->shm_segsz < params->u.size)
 475                 return -EINVAL;
 476
 477         return 0;
 478 }
 479
 480 asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
 481 {
 482         struct ipc_namespace *ns;
 483         struct ipc_ops shm_ops;
 484         struct ipc_params shm_params;
 485
 486         ns = current->nsproxy->ipc_ns;
 487
 488         shm_ops.getnew = newseg;
 489         shm_ops.associate = shm_security;
 490         shm_ops.more_checks = shm_more_checks;
 491
 492         shm_params.key = key;
 493         shm_params.flg = shmflg;
 494         shm_params.u.size = size;
 495
 496         return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
 497 }
 498
 499 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
 500 {
 501         switch(version) {
 502         case IPC_64:
 503                 return copy_to_user(buf, in, sizeof(*in));
 504         case IPC_OLD:
 505             {
 506                 struct shmid_ds out;
 507
 508                 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
 509                 out.shm_segsz   = in->shm_segsz;
 510                 out.shm_atime   = in->shm_atime;
 511                 out.shm_dtime   = in->shm_dtime;
 512                 out.shm_ctime   = in->shm_ctime;
 513                 out.shm_cpid    = in->shm_cpid;
 514                 out.shm_lpid    = in->shm_lpid;
 515                 out.shm_nattch  = in->shm_nattch;
 516
 517                 return copy_to_user(buf, &out, sizeof(out));
 518             }
 519         default:
 520                 return -EINVAL;
 521         }
 522 }
 523
 524 struct shm_setbuf {
 525         uid_t   uid;
 526         gid_t   gid;
 527         mode_t  mode;
 528 };
 529
 530 static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
 531 {
 532         switch(version) {
 533         case IPC_64:
 534             {
 535                 struct shmid64_ds tbuf;
 536
 537                 if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
 538                         return -EFAULT;
 539
 540                 out->uid        = tbuf.shm_perm.uid;
 541                 out->gid        = tbuf.shm_perm.gid;
 542                 out->mode       = tbuf.shm_perm.mode;
 543
 544                 return 0;
 545             }
 546         case IPC_OLD:
 547             {
 548                 struct shmid_ds tbuf_old;
 549
 550                 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
 551                         return -EFAULT;
 552
 553                 out->uid        = tbuf_old.shm_perm.uid;
 554                 out->gid        = tbuf_old.shm_perm.gid;
 555                 out->mode       = tbuf_old.shm_perm.mode;
 556
 557                 return 0;
 558             }
 559         default:
 560                 return -EINVAL;
 561         }
 562 }
 563
 564 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
 565 {
 566         switch(version) {
 567         case IPC_64:
 568                 return copy_to_user(buf, in, sizeof(*in));
 569         case IPC_OLD:
 570             {
 571                 struct shminfo out;
 572
 573                 if(in->shmmax > INT_MAX)
 574                         out.shmmax = INT_MAX;
 575                 else
 576                         out.shmmax = (int)in->shmmax;
 577
 578                 out.shmmin      = in->shmmin;
 579                 out.shmmni      = in->shmmni;
 580                 out.shmseg      = in->shmseg;
 581                 out.shmall      = in->shmall;
 582
 583                 return copy_to_user(buf, &out, sizeof(out));
 584             }
 585         default:
 586                 return -EINVAL;
 587         }
 588 }
 589
 590 /*
 591  * Called with shm_ids.rw_mutex held as a reader
 592  */
 593 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
 594                 unsigned long *swp)
 595 {
 596         int next_id;
 597         int total, in_use;
 598
 599         *rss = 0;
 600         *swp = 0;
 601
 602         in_use = shm_ids(ns).in_use;
 603
 604         for (total = 0, next_id = 0; total < in_use; next_id++) {
 605                 struct shmid_kernel *shp;
 606                 struct inode *inode;
 607
 608                 shp = idr_find(&shm_ids(ns).ipcs_idr, next_id);
 609                 if (shp == NULL)
 610                         continue;
 611
 612                 inode = shp->shm_file->f_path.dentry->d_inode;
 613
 614                 if (is_file_hugepages(shp->shm_file)) {
 615                         struct address_space *mapping = inode->i_mapping;
 616                         *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
 617                 } else {
 618                         struct shmem_inode_info *info = SHMEM_I(inode);
 619                         spin_lock(&info->lock);
 620                         *rss += inode->i_mapping->nrpages;
 621                         *swp += info->swapped;
 622                         spin_unlock(&info->lock);
 623                 }
 624
 625                 total++;
 626         }
 627 }
 628
 629 asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
 630 {
 631         struct shm_setbuf setbuf;
 632         struct shmid_kernel *shp;
 633         int err, version;
 634         struct ipc_namespace *ns;
 635
 636         if (cmd < 0 || shmid < 0) {
 637                 err = -EINVAL;
 638                 goto out;
 639         }
 640
 641         version = ipc_parse_version(&cmd);
 642         ns = current->nsproxy->ipc_ns;
 643
 644         switch (cmd) { /* replace with proc interface ? */
 645         case IPC_INFO:
 646         {
 647                 struct shminfo64 shminfo;
 648
 649                 err = security_shm_shmctl(NULL, cmd);
 650                 if (err)
 651                         return err;
 652
 653                 memset(&shminfo,0,sizeof(shminfo));
 654                 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
 655                 shminfo.shmmax = ns->shm_ctlmax;
 656                 shminfo.shmall = ns->shm_ctlall;
 657
 658                 shminfo.shmmin = SHMMIN;
 659                 if(copy_shminfo_to_user (buf, &shminfo, version))
 660                         return -EFAULT;
 661
 662                 down_read(&shm_ids(ns).rw_mutex);
 663                 err = ipc_get_maxid(&shm_ids(ns));
 664                 up_read(&shm_ids(ns).rw_mutex);
 665
 666                 if(err<0)
 667                         err = 0;
 668                 goto out;
 669         }
 670         case SHM_INFO:
 671         {
 672                 struct shm_info shm_info;
 673
 674                 err = security_shm_shmctl(NULL, cmd);
 675                 if (err)
 676                         return err;
 677
 678                 memset(&shm_info,0,sizeof(shm_info));
 679                 down_read(&shm_ids(ns).rw_mutex);
 680                 shm_info.used_ids = shm_ids(ns).in_use;
 681                 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
 682                 shm_info.shm_tot = ns->shm_tot;
 683                 shm_info.swap_attempts = 0;
 684                 shm_info.swap_successes = 0;
 685                 err = ipc_get_maxid(&shm_ids(ns));
 686                 up_read(&shm_ids(ns).rw_mutex);
 687                 if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
 688                         err = -EFAULT;
 689                         goto out;
 690                 }
 691
 692                 err = err < 0 ? 0 : err;
 693                 goto out;
 694         }
 695         case SHM_STAT:
 696         case IPC_STAT:
 697         {
 698                 struct shmid64_ds tbuf;
 699                 int result;
 700
 701                 if (!buf) {
 702                         err = -EFAULT;
 703                         goto out;
 704                 }
 705
 706                 if (cmd == SHM_STAT) {
 707                         shp = shm_lock(ns, shmid);
 708                         if (IS_ERR(shp)) {
 709                                 err = PTR_ERR(shp);
 710                                 goto out;
 711                         }
 712                         result = shp->shm_perm.id;
 713                 } else {
 714                         shp = shm_lock_check(ns, shmid);
 715                         if (IS_ERR(shp)) {
 716                                 err = PTR_ERR(shp);
 717                                 goto out;
 718                         }
 719                         result = 0;
 720                 }
 721                 err=-EACCES;
 722                 if (ipcperms (&shp->shm_perm, S_IRUGO))
 723                         goto out_unlock;
 724                 err = security_shm_shmctl(shp, cmd);
 725                 if (err)
 726                         goto out_unlock;
 727                 memset(&tbuf, 0, sizeof(tbuf));
 728                 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
 729                 tbuf.shm_segsz  = shp->shm_segsz;
 730                 tbuf.shm_atime  = shp->shm_atim;
 731                 tbuf.shm_dtime  = shp->shm_dtim;
 732                 tbuf.shm_ctime  = shp->shm_ctim;
 733                 tbuf.shm_cpid   = shp->shm_cprid;
 734                 tbuf.shm_lpid   = shp->shm_lprid;
 735                 tbuf.shm_nattch = shp->shm_nattch;
 736                 shm_unlock(shp);
 737                 if(copy_shmid_to_user (buf, &tbuf, version))
 738                         err = -EFAULT;
 739                 else
 740                         err = result;
 741                 goto out;
 742         }
 743         case SHM_LOCK:
 744         case SHM_UNLOCK:
 745         {
 746                 shp = shm_lock_check(ns, shmid);
 747                 if (IS_ERR(shp)) {
 748                         err = PTR_ERR(shp);
 749                         goto out;
 750                 }
 751
 752                 err = audit_ipc_obj(&(shp->shm_perm));
 753                 if (err)
 754                         goto out_unlock;
 755
 756                 if (!capable(CAP_IPC_LOCK)) {
 757                         err = -EPERM;
 758                         if (current->euid != shp->shm_perm.uid &&
 759                             current->euid != shp->shm_perm.cuid)
 760                                 goto out_unlock;
 761                         if (cmd == SHM_LOCK &&
 762                             !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
 763                                 goto out_unlock;
 764                 }
 765
 766                 err = security_shm_shmctl(shp, cmd);
 767                 if (err)
 768                         goto out_unlock;
 769
 770                 if(cmd==SHM_LOCK) {
 771                         struct user_struct * user = current->user;
 772                         if (!is_file_hugepages(shp->shm_file)) {
 773                                 err = shmem_lock(shp->shm_file, 1, user);
 774                                 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
 775                                         shp->shm_perm.mode |= SHM_LOCKED;
 776                                         shp->mlock_user = user;
 777                                 }
 778                         }
 779                 } else if (!is_file_hugepages(shp->shm_file)) {
 780                         shmem_lock(shp->shm_file, 0, shp->mlock_user);
 781                         shp->shm_perm.mode &= ~SHM_LOCKED;
 782                         shp->mlock_user = NULL;
 783                 }
 784                 shm_unlock(shp);
 785                 goto out;
 786         }
 787         case IPC_RMID:
 788         {
 789                 /*
 790                  *      We cannot simply remove the file. The SVID states
 791                  *      that the block remains until the last person
 792                  *      detaches from it, then is deleted. A shmat() on
 793                  *      an RMID segment is legal in older Linux and if
 794                  *      we change it apps break...
 795                  *
 796                  *      Instead we set a destroyed flag, and then blow
 797                  *      the name away when the usage hits zero.
 798                  */
 799                 down_write(&shm_ids(ns).rw_mutex);
 800                 shp = shm_lock_check_down(ns, shmid);
 801                 if (IS_ERR(shp)) {
 802                         err = PTR_ERR(shp);
 803                         goto out_up;
 804                 }
 805
 806                 err = audit_ipc_obj(&(shp->shm_perm));
 807                 if (err)
 808                         goto out_unlock_up;
 809
 810                 if (current->euid != shp->shm_perm.uid &&
 811                     current->euid != shp->shm_perm.cuid &&
 812                     !capable(CAP_SYS_ADMIN)) {
 813                         err=-EPERM;
 814                         goto out_unlock_up;
 815                 }
 816
 817                 err = security_shm_shmctl(shp, cmd);
 818                 if (err)
 819                         goto out_unlock_up;
 820
 821                 do_shm_rmid(ns, &shp->shm_perm);
 822                 up_write(&shm_ids(ns).rw_mutex);
 823                 goto out;
 824         }
 825
 826         case IPC_SET:
 827         {
 828                 if (!buf) {
 829                         err = -EFAULT;
 830                         goto out;
 831                 }
 832
 833                 if (copy_shmid_from_user (&setbuf, buf, version)) {
 834                         err = -EFAULT;
 835                         goto out;
 836                 }
 837                 down_write(&shm_ids(ns).rw_mutex);
 838                 shp = shm_lock_check_down(ns, shmid);
 839                 if (IS_ERR(shp)) {
 840                         err = PTR_ERR(shp);
 841                         goto out_up;
 842                 }
 843                 err = audit_ipc_obj(&(shp->shm_perm));
 844                 if (err)
 845                         goto out_unlock_up;
 846                 err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode);
 847                 if (err)
 848                         goto out_unlock_up;
 849                 err=-EPERM;
 850                 if (current->euid != shp->shm_perm.uid &&
 851                     current->euid != shp->shm_perm.cuid &&
 852                     !capable(CAP_SYS_ADMIN)) {
 853                         goto out_unlock_up;
 854                 }
 855
 856                 err = security_shm_shmctl(shp, cmd);
 857                 if (err)
 858                         goto out_unlock_up;
 859
 860                 shp->shm_perm.uid = setbuf.uid;
 861                 shp->shm_perm.gid = setbuf.gid;
 862                 shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO)
 863                         | (setbuf.mode & S_IRWXUGO);
 864                 shp->shm_ctim = get_seconds();
 865                 break;
 866         }
 867
 868         default:
 869                 err = -EINVAL;
 870                 goto out;
 871         }
 872
 873         err = 0;
 874 out_unlock_up:
 875         shm_unlock(shp);
 876 out_up:
 877         up_write(&shm_ids(ns).rw_mutex);
 878         goto out;
 879 out_unlock:
 880         shm_unlock(shp);
 881 out:
 882         return err;
 883 }
 884
 885 /*
 886  * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
 887  *
 888  * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
 889  * "raddr" thing points to kernel space, and there has to be a wrapper around
 890  * this.
 891  */
 892 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
 893 {
 894         struct shmid_kernel *shp;
 895         unsigned long addr;
 896         unsigned long size;
 897         struct file * file;
 898         int    err;
 899         unsigned long flags;
 900         unsigned long prot;
 901         int acc_mode;
 902         unsigned long user_addr;
 903         struct ipc_namespace *ns;
 904         struct shm_file_data *sfd;
 905         struct path path;
 906         mode_t f_mode;
 907
 908         err = -EINVAL;
 909         if (shmid < 0)
 910                 goto out;
 911         else if ((addr = (ulong)shmaddr)) {
 912                 if (addr & (SHMLBA-1)) {
 913                         if (shmflg & SHM_RND)
 914                                 addr &= ~(SHMLBA-1);       /* round down */
 915                         else
 916 #ifndef __ARCH_FORCE_SHMLBA
 917                                 if (addr & ~PAGE_MASK)
 918 #endif
 919                                         goto out;
 920                 }
 921                 flags = MAP_SHARED | MAP_FIXED;
 922         } else {
 923                 if ((shmflg & SHM_REMAP))
 924                         goto out;
 925
 926                 flags = MAP_SHARED;
 927         }
 928
 929         if (shmflg & SHM_RDONLY) {
 930                 prot = PROT_READ;
 931                 acc_mode = S_IRUGO;
 932                 f_mode = FMODE_READ;
 933         } else {
 934                 prot = PROT_READ | PROT_WRITE;
 935                 acc_mode = S_IRUGO | S_IWUGO;
 936                 f_mode = FMODE_READ | FMODE_WRITE;
 937         }
 938         if (shmflg & SHM_EXEC) {
 939                 prot |= PROT_EXEC;
 940                 acc_mode |= S_IXUGO;
 941         }
 942
 943         /*
 944          * We cannot rely on the fs check since SYSV IPC does have an
 945          * additional creator id...
 946          */
 947         ns = current->nsproxy->ipc_ns;
 948         shp = shm_lock_check(ns, shmid);
 949         if (IS_ERR(shp)) {
 950                 err = PTR_ERR(shp);
 951                 goto out;
 952         }
 953
 954         err = -EACCES;
 955         if (ipcperms(&shp->shm_perm, acc_mode))
 956                 goto out_unlock;
 957
 958         err = security_shm_shmat(shp, shmaddr, shmflg);
 959         if (err)
 960                 goto out_unlock;
 961
 962         path.dentry = dget(shp->shm_file->f_path.dentry);
 963         path.mnt    = shp->shm_file->f_path.mnt;
 964         shp->shm_nattch++;
 965         size = i_size_read(path.dentry->d_inode);
 966         shm_unlock(shp);
 967
 968         err = -ENOMEM;
 969         sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
 970         if (!sfd)
 971                 goto out_put_dentry;
 972
 973         err = -ENOMEM;
 974
 975         file = alloc_file(path.mnt, path.dentry, f_mode, &shm_file_operations);
 976         if (!file)
 977                 goto out_free;
 978
 979         file->private_data = sfd;
 980         file->f_mapping = shp->shm_file->f_mapping;
 981         sfd->id = shp->shm_perm.id;
 982         sfd->ns = get_ipc_ns(ns);
 983         sfd->file = shp->shm_file;
 984         sfd->vm_ops = NULL;
 985
 986         down_write(&current->mm->mmap_sem);
 987         if (addr && !(shmflg & SHM_REMAP)) {
 988                 err = -EINVAL;
 989                 if (find_vma_intersection(current->mm, addr, addr + size))
 990                         goto invalid;
 991                 /*
 992                  * If shm segment goes below stack, make sure there is some
 993                  * space left for the stack to grow (at least 4 pages).
 994                  */
 995                 if (addr < current->mm->start_stack &&
 996                     addr > current->mm->start_stack - size - PAGE_SIZE * 5)
 997                         goto invalid;
 998         }
 999
1000         user_addr = do_mmap (file, addr, size, prot, flags, 0);
1001         *raddr = user_addr;
1002         err = 0;
1003         if (IS_ERR_VALUE(user_addr))
1004                 err = (long)user_addr;
1005 invalid:
1006         up_write(&current->mm->mmap_sem);
1007
1008         fput(file);
1009
1010 out_nattch:
1011         down_write(&shm_ids(ns).rw_mutex);
1012         shp = shm_lock_down(ns, shmid);
1013         BUG_ON(IS_ERR(shp));
1014         shp->shm_nattch--;
1015         if(shp->shm_nattch == 0 &&
1016            shp->shm_perm.mode & SHM_DEST)
1017                 shm_destroy(ns, shp);
1018         else
1019                 shm_unlock(shp);
1020         up_write(&shm_ids(ns).rw_mutex);
1021
1022 out:
1023         return err;
1024
1025 out_unlock:
1026         shm_unlock(shp);
1027         goto out;
1028
1029 out_free:
1030         kfree(sfd);
1031 out_put_dentry:
1032         dput(path.dentry);
1033         goto out_nattch;
1034 }
1035
1036 asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
1037 {
1038         unsigned long ret;
1039         long err;
1040
1041         err = do_shmat(shmid, shmaddr, shmflg, &ret);
1042         if (err)
1043                 return err;
1044         force_successful_syscall_return();
1045         return (long)ret;
1046 }
1047
1048 /*
1049  * detach and kill segment if marked destroyed.
1050  * The work is done in shm_close.
1051  */
1052 asmlinkage long sys_shmdt(char __user *shmaddr)
1053 {
1054         struct mm_struct *mm = current->mm;
1055         struct vm_area_struct *vma, *next;
1056         unsigned long addr = (unsigned long)shmaddr;
1057         loff_t size = 0;
1058         int retval = -EINVAL;
1059
1060         if (addr & ~PAGE_MASK)
1061                 return retval;
1062
1063         down_write(&mm->mmap_sem);
1064
1065         /*
1066          * This function tries to be smart and unmap shm segments that
1067          * were modified by partial mlock or munmap calls:
1068          * - It first determines the size of the shm segment that should be
1069          *   unmapped: It searches for a vma that is backed by shm and that
1070          *   started at address shmaddr. It records it's size and then unmaps
1071          *   it.
1072          * - Then it unmaps all shm vmas that started at shmaddr and that
1073          *   are within the initially determined size.
1074          * Errors from do_munmap are ignored: the function only fails if
1075          * it's called with invalid parameters or if it's called to unmap
1076          * a part of a vma. Both calls in this function are for full vmas,
1077          * the parameters are directly copied from the vma itself and always
1078          * valid - therefore do_munmap cannot fail. (famous last words?)
1079          */
1080         /*
1081          * If it had been mremap()'d, the starting address would not
1082          * match the usual checks anyway. So assume all vma's are
1083          * above the starting address given.
1084          */
1085         vma = find_vma(mm, addr);
1086
1087         while (vma) {
1088                 next = vma->vm_next;
1089
1090                 /*
1091                  * Check if the starting address would match, i.e. it's
1092                  * a fragment created by mprotect() and/or munmap(), or it
1093                  * otherwise it starts at this address with no hassles.
1094                  */
1095                 if ((vma->vm_ops == &shm_vm_ops) &&
1096                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1097
1098
1099                         size = vma->vm_file->f_path.dentry->d_inode->i_size;
1100                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1101                         /*
1102                          * We discovered the size of the shm segment, so
1103                          * break out of here and fall through to the next
1104                          * loop that uses the size information to stop
1105                          * searching for matching vma's.
1106                          */
1107                         retval = 0;
1108                         vma = next;
1109                         break;
1110                 }
1111                 vma = next;
1112         }
1113
1114         /*
1115          * We need look no further than the maximum address a fragment
1116          * could possibly have landed at. Also cast things to loff_t to
1117          * prevent overflows and make comparisions vs. equal-width types.
1118          */
1119         size = PAGE_ALIGN(size);
1120         while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1121                 next = vma->vm_next;
1122
1123                 /* finding a matching vma now does not alter retval */
1124                 if ((vma->vm_ops == &shm_vm_ops) &&
1125                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1126
1127                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1128                 vma = next;
1129         }
1130
1131         up_write(&mm->mmap_sem);
1132         return retval;
1133 }
1134
1135 #ifdef CONFIG_PROC_FS
1136 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1137 {
1138         struct shmid_kernel *shp = it;
1139         char *format;
1140
1141 #define SMALL_STRING "%10d %10d  %4o %10u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1142 #define BIG_STRING   "%10d %10d  %4o %21u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1143
1144         if (sizeof(size_t) <= sizeof(int))
1145                 format = SMALL_STRING;
1146         else
1147                 format = BIG_STRING;
1148         return seq_printf(s, format,
1149                           shp->shm_perm.key,
1150                           shp->shm_perm.id,
1151                           shp->shm_perm.mode,
1152                           shp->shm_segsz,
1153                           shp->shm_cprid,
1154                           shp->shm_lprid,
1155                           shp->shm_nattch,
1156                           shp->shm_perm.uid,
1157                           shp->shm_perm.gid,
1158                           shp->shm_perm.cuid,
1159                           shp->shm_perm.cgid,
1160                           shp->shm_atim,
1161                           shp->shm_dtim,
1162                           shp->shm_ctim);
1163 }
1164 #endif