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