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 <bsm/audit_kernel.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 /*
 158  *      Routine:        macx_swapon
 159  *      Function:
 160  *              Syscall interface to add a file to backing store
 161  */
 162 int
 163 macx_swapon(
 164         struct macx_swapon_args *args)
 165 {
 166         int                     size = args->size;
 167         vnode_t                 vp = (vnode_t)NULL;
 168         struct nameidata        nd, *ndp;
 169         register int            error;
 170         kern_return_t           kr;
 171         mach_port_t             backing_store;
 172         memory_object_default_t default_pager;
 173         int                     i;
 174         boolean_t               funnel_state;
 175         off_t                   file_size;
 176         vfs_context_t           ctx = vfs_context_current();
 177         struct proc             *p =  current_proc();
 178
 179         AUDIT_MACH_SYSCALL_ENTER(AUE_SWAPON);
 180         AUDIT_ARG(value, args->priority);
 181
 182         funnel_state = thread_funnel_set(kernel_flock, TRUE);
 183         ndp = &nd;
 184
 185         if ((error = suser(kauth_cred_get(), 0)))
 186                 goto swapon_bailout;
 187
 188         if(default_pager_init_flag == 0) {
 189                 start_def_pager(NULL);
 190                 default_pager_init_flag = 1;
 191         }
 192
 193         /*
 194          * Get a vnode for the paging area.
 195          */
 196         NDINIT(ndp, LOOKUP, FOLLOW | LOCKLEAF | AUDITVNPATH1,
 197                ((IS_64BIT_PROCESS(p)) ? UIO_USERSPACE64 : UIO_USERSPACE32),
 198                CAST_USER_ADDR_T(args->filename), ctx);
 199
 200         if ((error = namei(ndp)))
 201                 goto swapon_bailout;
 202         nameidone(ndp);
 203         vp = ndp->ni_vp;
 204
 205         if (vp->v_type != VREG) {
 206                 error = EINVAL;
 207                 goto swapon_bailout;
 208         }
 209
 210         /* get file size */
 211         if ((error = vnode_size(vp, &file_size, ctx)) != 0)
 212                 goto swapon_bailout;
 213 #if CONFIG_MACF
 214         vnode_lock(vp);
 215         error = mac_system_check_swapon(vfs_context_ucred(ctx), vp);
 216         vnode_unlock(vp);
 217         if (error)
 218                 goto swapon_bailout;
 219 #endif
 220
 221         /* resize to desired size if it's too small */
 222         if ((file_size < (off_t)size) && ((error = vnode_setsize(vp, (off_t)size, 0, ctx)) != 0))
 223                 goto swapon_bailout;
 224
 225         /* add new backing store to list */
 226         i = 0;
 227         while(bs_port_table[i].vp != 0) {
 228                 if(i == MAX_BACKING_STORE)
 229                         break;
 230                 i++;
 231         }
 232         if(i == MAX_BACKING_STORE) {
 233                 error = ENOMEM;
 234                 goto swapon_bailout;
 235         }
 236
 237         /* remember the vnode. This vnode has namei() reference */
 238         bs_port_table[i].vp = vp;
 239
 240         /*
 241          * Look to see if we are already paging to this file.
 242          */
 243         /* make certain the copy send of kernel call will work */
 244         default_pager = MEMORY_OBJECT_DEFAULT_NULL;
 245         kr = host_default_memory_manager(host_priv_self(), &default_pager, 0);
 246         if(kr != KERN_SUCCESS) {
 247            error = EAGAIN;
 248            bs_port_table[i].vp = 0;
 249            goto swapon_bailout;
 250         }
 251
 252         kr = default_pager_backing_store_create(default_pager,
 253                                         -1, /* default priority */
 254                                         0, /* default cluster size */
 255                                         &backing_store);
 256         memory_object_default_deallocate(default_pager);
 257
 258         if(kr != KERN_SUCCESS) {
 259            error = ENOMEM;
 260            bs_port_table[i].vp = 0;
 261            goto swapon_bailout;
 262         }
 263
 264         /*
 265          * NOTE: we are able to supply PAGE_SIZE here instead of
 266          *      an actual record size or block number because:
 267          *      a: we do not support offsets from the beginning of the
 268          *              file (allowing for non page size/record modulo offsets.
 269          *      b: because allow paging will be done modulo page size
 270          */
 271
 272         kr = default_pager_add_file(backing_store, (vnode_ptr_t) vp,
 273                                 PAGE_SIZE, (int)(file_size/PAGE_SIZE));
 274         if(kr != KERN_SUCCESS) {
 275            bs_port_table[i].vp = 0;
 276            if(kr == KERN_INVALID_ARGUMENT)
 277                 error = EINVAL;
 278            else
 279                 error = ENOMEM;
 280            goto swapon_bailout;
 281         }
 282         bs_port_table[i].bs = (void *)backing_store;
 283         error = 0;
 284
 285         /* Mark this vnode as being used for swapfile */
 286         SET(vp->v_flag, VSWAP);
 287
 288         ubc_setthreadcred(vp, p, current_thread());
 289
 290         /*
 291          * take a long term reference on the vnode to keep
 292          * vnreclaim() away from this vnode.
 293          */
 294         vnode_ref(vp);
 295
 296 swapon_bailout:
 297         if (vp) {
 298                 vnode_put(vp);
 299         }
 300         (void) thread_funnel_set(kernel_flock, FALSE);
 301         AUDIT_MACH_SYSCALL_EXIT(error);
 302         return(error);
 303 }
 304
 305 /*
 306  *      Routine:        macx_swapoff
 307  *      Function:
 308  *              Syscall interface to remove a file from backing store
 309  */
 310 int
 311 macx_swapoff(
 312         struct macx_swapoff_args *args)
 313 {
 314         __unused int    flags = args->flags;
 315         kern_return_t   kr;
 316         mach_port_t     backing_store;
 317
 318         struct vnode            *vp = 0;
 319         struct nameidata        nd, *ndp;
 320         struct proc             *p =  current_proc();
 321         int                     i;
 322         int                     error;
 323         boolean_t               funnel_state;
 324         vfs_context_t ctx = vfs_context_current();
 325
 326         AUDIT_MACH_SYSCALL_ENTER(AUE_SWAPOFF);
 327
 328         funnel_state = thread_funnel_set(kernel_flock, TRUE);
 329         backing_store = NULL;
 330         ndp = &nd;
 331
 332         if ((error = suser(kauth_cred_get(), 0)))
 333                 goto swapoff_bailout;
 334
 335         /*
 336          * Get the vnode for the paging area.
 337          */
 338         NDINIT(ndp, LOOKUP, FOLLOW | LOCKLEAF | AUDITVNPATH1,
 339                ((IS_64BIT_PROCESS(p)) ? UIO_USERSPACE64 : UIO_USERSPACE32),
 340                CAST_USER_ADDR_T(args->filename), ctx);
 341
 342         if ((error = namei(ndp)))
 343                 goto swapoff_bailout;
 344         nameidone(ndp);
 345         vp = ndp->ni_vp;
 346
 347         if (vp->v_type != VREG) {
 348                 error = EINVAL;
 349                 goto swapoff_bailout;
 350         }
 351 #if CONFIG_MACF
 352         vnode_lock(vp);
 353         error = mac_system_check_swapoff(vfs_context_ucred(ctx), vp);
 354         vnode_unlock(vp);
 355         if (error)
 356                 goto swapoff_bailout;
 357 #endif
 358
 359         for(i = 0; i < MAX_BACKING_STORE; i++) {
 360                 if(bs_port_table[i].vp == vp) {
 361                         break;
 362                 }
 363         }
 364         if (i == MAX_BACKING_STORE) {
 365                 error = EINVAL;
 366                 goto swapoff_bailout;
 367         }
 368         backing_store = (mach_port_t)bs_port_table[i].bs;
 369
 370         kr = default_pager_backing_store_delete(backing_store);
 371         switch (kr) {
 372                 case KERN_SUCCESS:
 373                         error = 0;
 374                         bs_port_table[i].vp = 0;
 375                         /* This vnode is no longer used for swapfile */
 376                         CLR(vp->v_flag, VSWAP);
 377
 378                         /* get rid of macx_swapon() "long term" reference */
 379                         vnode_rele(vp);
 380
 381                         break;
 382                 case KERN_FAILURE:
 383                         error = EAGAIN;
 384                         break;
 385                 default:
 386                         error = EAGAIN;
 387                         break;
 388         }
 389
 390 swapoff_bailout:
 391         /* get rid of macx_swapoff() namei() reference */
 392         if (vp)
 393                 vnode_put(vp);
 394
 395         (void) thread_funnel_set(kernel_flock, FALSE);
 396         AUDIT_MACH_SYSCALL_EXIT(error);
 397         return(error);
 398 }
 399
 400 /*
 401  *      Routine:        macx_swapinfo
 402  *      Function:
 403  *              Syscall interface to get general swap statistics
 404  */
 405 int
 406 macx_swapinfo(
 407         memory_object_size_t    *total_p,
 408         memory_object_size_t    *avail_p,
 409         vm_size_t               *pagesize_p,
 410         boolean_t               *encrypted_p)
 411 {
 412         int                     error;
 413         memory_object_default_t default_pager;
 414         default_pager_info_64_t dpi64;
 415         kern_return_t           kr;
 416
 417         error = 0;
 418
 419         /*
 420          * Get a handle on the default pager.
 421          */
 422         default_pager = MEMORY_OBJECT_DEFAULT_NULL;
 423         kr = host_default_memory_manager(host_priv_self(), &default_pager, 0);
 424         if (kr != KERN_SUCCESS) {
 425                 error = EAGAIN; /* XXX why EAGAIN ? */
 426                 goto done;
 427         }
 428         if (default_pager == MEMORY_OBJECT_DEFAULT_NULL) {
 429                 /*
 430                  * The default pager has not initialized yet,
 431                  * so it can't be using any swap space at all.
 432                  */
 433                 *total_p = 0;
 434                 *avail_p = 0;
 435                 *pagesize_p = 0;
 436                 *encrypted_p = FALSE;
 437                 goto done;
 438         }
 439
 440         /*
 441          * Get swap usage data from default pager.
 442          */
 443         kr = default_pager_info_64(default_pager, &dpi64);
 444         if (kr != KERN_SUCCESS) {
 445                 error = ENOTSUP;
 446                 goto done;
 447         }
 448
 449         /*
 450          * Provide default pager info to caller.
 451          */
 452         *total_p = dpi64.dpi_total_space;
 453         *avail_p = dpi64.dpi_free_space;
 454         *pagesize_p = dpi64.dpi_page_size;
 455         if (dpi64.dpi_flags & DPI_ENCRYPTED) {
 456                 *encrypted_p = TRUE;
 457         } else {
 458                 *encrypted_p = FALSE;
 459         }
 460
 461 done:
 462         if (default_pager != MEMORY_OBJECT_DEFAULT_NULL) {
 463                 /* release our handle on default pager */
 464                 memory_object_default_deallocate(default_pager);
 465         }
 466         return error;
 467 }