bsd/vm/dp_backing_file.c

   1 /*
   2  * Copyright (c) 2000-2007 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*
  29  * NOTICE: This file was modified by SPARTA, Inc. in 2005 to introduce
  30  * support for mandatory and extensible security protections.  This notice
  31  * is included in support of clause 2.2 (b) of the Apple Public License,
  32  * Version 2.0.
  33  */
  34
  35 #include <sys/param.h>
  36 #include <sys/systm.h>
  37 #include <sys/lock.h>
  38 #include <sys/proc_internal.h>
  39 #include <sys/kauth.h>
  40 #include <sys/buf.h>
  41 #include <sys/uio.h>
  42 #include <sys/vnode_internal.h>
  43 #include <sys/namei.h>
  44 #include <sys/ubc_internal.h>
  45 #include <sys/malloc.h>
  46
  47 #include <default_pager/default_pager_types.h>
  48 #include <default_pager/default_pager_object.h>
  49
  50 #include <security/audit/audit.h>
  51 #include <bsm/audit_kevents.h>
  52
  53 #include <mach/mach_types.h>
  54 #include <mach/host_priv.h>
  55 #include <mach/mach_traps.h>
  56 #include <mach/boolean.h>
  57
  58 #include <kern/kern_types.h>
  59 #include <kern/host.h>
  60 #include <kern/task.h>
  61 #include <kern/zalloc.h>
  62 #include <kern/kalloc.h>
  63 #include <kern/assert.h>
  64
  65 #include <libkern/libkern.h>
  66
  67 #include <vm/vm_pageout.h>
  68 #include <vm/vm_map.h>
  69 #include <vm/vm_kern.h>
  70 #include <vm/vnode_pager.h>
  71 #include <vm/vm_protos.h>
  72 #if CONFIG_MACF
  73 #include <security/mac_framework.h>
  74 #endif
  75
  76 /*
  77  * temporary support for delayed instantiation
  78  * of default_pager
  79  */
  80 int default_pager_init_flag = 0;
  81
  82 struct bs_map           bs_port_table[MAX_BACKING_STORE] = {
  83         {0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  84         {0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  85         {0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  86         {0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  87         {0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  88         {0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  89         {0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  90         {0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  91         {0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  92         {0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0}};
  93
  94 /* ###################################################### */
  95
  96
  97 /*
  98  *      Routine:        macx_backing_store_recovery
  99  *      Function:
 100  *              Syscall interface to set a tasks privilege
 101  *              level so that it is not subject to
 102  *              macx_backing_store_suspend
 103  */
 104 int
 105 macx_backing_store_recovery(
 106         struct macx_backing_store_recovery_args *args)
 107 {
 108         int             pid = args->pid;
 109         int             error;
 110         struct proc     *p =  current_proc();
 111         boolean_t       funnel_state;
 112
 113         funnel_state = thread_funnel_set(kernel_flock, TRUE);
 114         if ((error = suser(kauth_cred_get(), 0)))
 115                 goto backing_store_recovery_return;
 116
 117         /* for now restrict backing_store_recovery */
 118         /* usage to only present task */
 119         if(pid != proc_selfpid()) {
 120                 error = EINVAL;
 121                 goto backing_store_recovery_return;
 122         }
 123
 124         task_backing_store_privileged(p->task);
 125
 126 backing_store_recovery_return:
 127         (void) thread_funnel_set(kernel_flock, FALSE);
 128         return(error);
 129 }
 130
 131 /*
 132  *      Routine:        macx_backing_store_suspend
 133  *      Function:
 134  *              Syscall interface to stop new demand for
 135  *              backing store when backing store is low
 136  */
 137
 138 int
 139 macx_backing_store_suspend(
 140         struct macx_backing_store_suspend_args *args)
 141 {
 142         boolean_t       suspend = args->suspend;
 143         int             error;
 144         boolean_t       funnel_state;
 145
 146         funnel_state = thread_funnel_set(kernel_flock, TRUE);
 147         if ((error = suser(kauth_cred_get(), 0)))
 148                 goto backing_store_suspend_return;
 149
 150         vm_backing_store_disable(suspend);
 151
 152 backing_store_suspend_return:
 153         (void) thread_funnel_set(kernel_flock, FALSE);
 154         return(error);
 155 }
 156
 157 extern boolean_t backing_store_stop_compaction;
 158
 159 /*
 160  *      Routine:        macx_backing_store_compaction
 161  *      Function:
 162  *              Turn compaction of swap space on or off.  This is
 163  *              used during shutdown/restart so that the kernel
 164  *              doesn't waste time compacting swap files that are
 165  *              about to be deleted anyway.  Compaction is always
 166  *              on by default when the system comes up and is turned
 167  *              off when a shutdown/restart is requested.  It is
 168  *              re-enabled if the shutdown/restart is aborted for any reason.
 169  */
 170
 171 int
 172 macx_backing_store_compaction(int flags)
 173 {
 174         int error;
 175
 176         if ((error = suser(kauth_cred_get(), 0)))
 177                 return error;
 178
 179         if (flags & SWAP_COMPACT_DISABLE) {
 180                 backing_store_stop_compaction = TRUE;
 181
 182         } else if (flags & SWAP_COMPACT_ENABLE) {
 183                 backing_store_stop_compaction = FALSE;
 184         }
 185
 186         return 0;
 187 }
 188
 189 /*
 190  *      Routine:        macx_triggers
 191  *      Function:
 192  *              Syscall interface to set the call backs for low and
 193  *              high water marks.
 194  */
 195 int
 196 macx_triggers(
 197         struct macx_triggers_args *args)
 198 {
 199         int     error;
 200
 201         error = suser(kauth_cred_get(), 0);
 202         if (error)
 203                 return error;
 204
 205         return mach_macx_triggers(args);
 206 }
 207
 208 /*
 209  *      Routine:        macx_swapon
 210  *      Function:
 211  *              Syscall interface to add a file to backing store
 212  */
 213 int
 214 macx_swapon(
 215         struct macx_swapon_args *args)
 216 {
 217         int                     size = args->size;
 218         vnode_t                 vp = (vnode_t)NULL;
 219         struct nameidata        nd, *ndp;
 220         register int            error;
 221         kern_return_t           kr;
 222         mach_port_t             backing_store;
 223         memory_object_default_t default_pager;
 224         int                     i;
 225         boolean_t               funnel_state;
 226         off_t                   file_size;
 227         vfs_context_t           ctx = vfs_context_current();
 228         struct proc             *p =  current_proc();
 229
 230         AUDIT_MACH_SYSCALL_ENTER(AUE_SWAPON);
 231         AUDIT_ARG(value32, args->priority);
 232
 233         funnel_state = thread_funnel_set(kernel_flock, TRUE);
 234         ndp = &nd;
 235
 236         if ((error = suser(kauth_cred_get(), 0)))
 237                 goto swapon_bailout;
 238
 239         if(default_pager_init_flag == 0) {
 240                 start_def_pager(NULL);
 241                 default_pager_init_flag = 1;
 242         }
 243
 244         /*
 245          * Get a vnode for the paging area.
 246          */
 247         NDINIT(ndp, LOOKUP, FOLLOW | LOCKLEAF | AUDITVNPATH1,
 248                ((IS_64BIT_PROCESS(p)) ? UIO_USERSPACE64 : UIO_USERSPACE32),
 249                (user_addr_t) args->filename, ctx);
 250
 251         if ((error = namei(ndp)))
 252                 goto swapon_bailout;
 253         nameidone(ndp);
 254         vp = ndp->ni_vp;
 255
 256         if (vp->v_type != VREG) {
 257                 error = EINVAL;
 258                 goto swapon_bailout;
 259         }
 260
 261         /* get file size */
 262         if ((error = vnode_size(vp, &file_size, ctx)) != 0)
 263                 goto swapon_bailout;
 264 #if CONFIG_MACF
 265         vnode_lock(vp);
 266         error = mac_system_check_swapon(vfs_context_ucred(ctx), vp);
 267         vnode_unlock(vp);
 268         if (error)
 269                 goto swapon_bailout;
 270 #endif
 271
 272         /* resize to desired size if it's too small */
 273         if ((file_size < (off_t)size) && ((error = vnode_setsize(vp, (off_t)size, 0, ctx)) != 0))
 274                 goto swapon_bailout;
 275
 276         /* add new backing store to list */
 277         i = 0;
 278         while(bs_port_table[i].vp != 0) {
 279                 if(i == MAX_BACKING_STORE)
 280                         break;
 281                 i++;
 282         }
 283         if(i == MAX_BACKING_STORE) {
 284                 error = ENOMEM;
 285                 goto swapon_bailout;
 286         }
 287
 288         /* remember the vnode. This vnode has namei() reference */
 289         bs_port_table[i].vp = vp;
 290
 291         /*
 292          * Look to see if we are already paging to this file.
 293          */
 294         /* make certain the copy send of kernel call will work */
 295         default_pager = MEMORY_OBJECT_DEFAULT_NULL;
 296         kr = host_default_memory_manager(host_priv_self(), &default_pager, 0);
 297         if(kr != KERN_SUCCESS) {
 298            error = EAGAIN;
 299            bs_port_table[i].vp = 0;
 300            goto swapon_bailout;
 301         }
 302
 303         kr = default_pager_backing_store_create(default_pager,
 304                                         -1, /* default priority */
 305                                         0, /* default cluster size */
 306                                         &backing_store);
 307         memory_object_default_deallocate(default_pager);
 308
 309         if(kr != KERN_SUCCESS) {
 310            error = ENOMEM;
 311            bs_port_table[i].vp = 0;
 312            goto swapon_bailout;
 313         }
 314
 315         /* Mark this vnode as being used for swapfile */
 316         vnode_lock_spin(vp);
 317         SET(vp->v_flag, VSWAP);
 318         vnode_unlock(vp);
 319
 320         /*
 321          * NOTE: we are able to supply PAGE_SIZE here instead of
 322          *      an actual record size or block number because:
 323          *      a: we do not support offsets from the beginning of the
 324          *              file (allowing for non page size/record modulo offsets.
 325          *      b: because allow paging will be done modulo page size
 326          */
 327
 328         kr = default_pager_add_file(backing_store, (vnode_ptr_t) vp,
 329                                 PAGE_SIZE, (int)(file_size/PAGE_SIZE));
 330         if(kr != KERN_SUCCESS) {
 331            bs_port_table[i].vp = 0;
 332            if(kr == KERN_INVALID_ARGUMENT)
 333                 error = EINVAL;
 334            else
 335                 error = ENOMEM;
 336
 337            /* This vnode is not to be used for swapfile */
 338            vnode_lock_spin(vp);
 339            CLR(vp->v_flag, VSWAP);
 340            vnode_unlock(vp);
 341
 342            goto swapon_bailout;
 343         }
 344         bs_port_table[i].bs = (void *)backing_store;
 345         error = 0;
 346
 347         ubc_setthreadcred(vp, p, current_thread());
 348
 349         /*
 350          * take a long term reference on the vnode to keep
 351          * vnreclaim() away from this vnode.
 352          */
 353         vnode_ref(vp);
 354
 355 swapon_bailout:
 356         if (vp) {
 357                 vnode_put(vp);
 358         }
 359         (void) thread_funnel_set(kernel_flock, FALSE);
 360         AUDIT_MACH_SYSCALL_EXIT(error);
 361         return(error);
 362 }
 363
 364 /*
 365  *      Routine:        macx_swapoff
 366  *      Function:
 367  *              Syscall interface to remove a file from backing store
 368  */
 369 int
 370 macx_swapoff(
 371         struct macx_swapoff_args *args)
 372 {
 373         __unused int    flags = args->flags;
 374         kern_return_t   kr;
 375         mach_port_t     backing_store;
 376
 377         struct vnode            *vp = 0;
 378         struct nameidata        nd, *ndp;
 379         struct proc             *p =  current_proc();
 380         int                     i;
 381         int                     error;
 382         boolean_t               funnel_state;
 383         vfs_context_t ctx = vfs_context_current();
 384
 385         AUDIT_MACH_SYSCALL_ENTER(AUE_SWAPOFF);
 386
 387         funnel_state = thread_funnel_set(kernel_flock, TRUE);
 388         backing_store = NULL;
 389         ndp = &nd;
 390
 391         if ((error = suser(kauth_cred_get(), 0)))
 392                 goto swapoff_bailout;
 393
 394         /*
 395          * Get the vnode for the paging area.
 396          */
 397         NDINIT(ndp, LOOKUP, FOLLOW | LOCKLEAF | AUDITVNPATH1,
 398                ((IS_64BIT_PROCESS(p)) ? UIO_USERSPACE64 : UIO_USERSPACE32),
 399                (user_addr_t) args->filename, ctx);
 400
 401         if ((error = namei(ndp)))
 402                 goto swapoff_bailout;
 403         nameidone(ndp);
 404         vp = ndp->ni_vp;
 405
 406         if (vp->v_type != VREG) {
 407                 error = EINVAL;
 408                 goto swapoff_bailout;
 409         }
 410 #if CONFIG_MACF
 411         vnode_lock(vp);
 412         error = mac_system_check_swapoff(vfs_context_ucred(ctx), vp);
 413         vnode_unlock(vp);
 414         if (error)
 415                 goto swapoff_bailout;
 416 #endif
 417
 418         for(i = 0; i < MAX_BACKING_STORE; i++) {
 419                 if(bs_port_table[i].vp == vp) {
 420                         break;
 421                 }
 422         }
 423         if (i == MAX_BACKING_STORE) {
 424                 error = EINVAL;
 425                 goto swapoff_bailout;
 426         }
 427         backing_store = (mach_port_t)bs_port_table[i].bs;
 428
 429         kr = default_pager_backing_store_delete(backing_store);
 430         switch (kr) {
 431                 case KERN_SUCCESS:
 432                         error = 0;
 433                         bs_port_table[i].vp = 0;
 434                         /* This vnode is no longer used for swapfile */
 435                         vnode_lock_spin(vp);
 436                         CLR(vp->v_flag, VSWAP);
 437                         vnode_unlock(vp);
 438
 439                         /* get rid of macx_swapon() "long term" reference */
 440                         vnode_rele(vp);
 441
 442                         break;
 443                 case KERN_FAILURE:
 444                         error = EAGAIN;
 445                         break;
 446                 default:
 447                         error = EAGAIN;
 448                         break;
 449         }
 450
 451 swapoff_bailout:
 452         /* get rid of macx_swapoff() namei() reference */
 453         if (vp)
 454                 vnode_put(vp);
 455
 456         (void) thread_funnel_set(kernel_flock, FALSE);
 457         AUDIT_MACH_SYSCALL_EXIT(error);
 458         return(error);
 459 }
 460
 461 /*
 462  *      Routine:        macx_swapinfo
 463  *      Function:
 464  *              Syscall interface to get general swap statistics
 465  */
 466 int
 467 macx_swapinfo(
 468         memory_object_size_t    *total_p,
 469         memory_object_size_t    *avail_p,
 470         vm_size_t               *pagesize_p,
 471         boolean_t               *encrypted_p)
 472 {
 473         int                     error;
 474         memory_object_default_t default_pager;
 475         default_pager_info_64_t dpi64;
 476         kern_return_t           kr;
 477
 478         error = 0;
 479
 480         /*
 481          * Get a handle on the default pager.
 482          */
 483         default_pager = MEMORY_OBJECT_DEFAULT_NULL;
 484         kr = host_default_memory_manager(host_priv_self(), &default_pager, 0);
 485         if (kr != KERN_SUCCESS) {
 486                 error = EAGAIN; /* XXX why EAGAIN ? */
 487                 goto done;
 488         }
 489         if (default_pager == MEMORY_OBJECT_DEFAULT_NULL) {
 490                 /*
 491                  * The default pager has not initialized yet,
 492                  * so it can't be using any swap space at all.
 493                  */
 494                 *total_p = 0;
 495                 *avail_p = 0;
 496                 *pagesize_p = 0;
 497                 *encrypted_p = FALSE;
 498                 goto done;
 499         }
 500
 501         /*
 502          * Get swap usage data from default pager.
 503          */
 504         kr = default_pager_info_64(default_pager, &dpi64);
 505         if (kr != KERN_SUCCESS) {
 506                 error = ENOTSUP;
 507                 goto done;
 508         }
 509
 510         /*
 511          * Provide default pager info to caller.
 512          */
 513         *total_p = dpi64.dpi_total_space;
 514         *avail_p = dpi64.dpi_free_space;
 515         *pagesize_p = dpi64.dpi_page_size;
 516         if (dpi64.dpi_flags & DPI_ENCRYPTED) {
 517                 *encrypted_p = TRUE;
 518         } else {
 519                 *encrypted_p = FALSE;
 520         }
 521
 522 done:
 523         if (default_pager != MEMORY_OBJECT_DEFAULT_NULL) {
 524                 /* release our handle on default pager */
 525                 memory_object_default_deallocate(default_pager);
 526         }
 527         return error;
 528 }