bsd/vm/dp_backing_file.c

   1 /*
   2  * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_OSREFERENCE_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
  10  * License may not be used to create, or enable the creation or
  11  * redistribution of, unlawful or unlicensed copies of an Apple operating
  12  * system, or to circumvent, violate, or enable the circumvention or
  13  * violation of, any terms of an Apple operating system software license
  14  * agreement.
  15  *
  16  * Please obtain a copy of the License at
  17  * http://www.opensource.apple.com/apsl/ and read it before using this
  18  * file.
  19  *
  20  * The Original Code and all software distributed under the License are
  21  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  22  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  23  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  25  * Please see the License for the specific language governing rights and
  26  * limitations under the License.
  27  *
  28  * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  29  */
  30
  31 #include <sys/param.h>
  32 #include <sys/systm.h>
  33 #include <sys/lock.h>
  34 #include <sys/proc_internal.h>
  35 #include <sys/kauth.h>
  36 #include <sys/buf.h>
  37 #include <sys/uio.h>
  38 #include <sys/vnode_internal.h>
  39 #include <sys/namei.h>
  40 #include <sys/ubc_internal.h>
  41 #include <sys/malloc.h>
  42
  43 #include <default_pager/default_pager_types.h>
  44 #include <default_pager/default_pager_object.h>
  45
  46 #include <bsm/audit_kernel.h>
  47 #include <bsm/audit_kevents.h>
  48
  49 #include <mach/mach_types.h>
  50 #include <mach/host_priv.h>
  51 #include <mach/mach_traps.h>
  52 #include <mach/boolean.h>
  53
  54 #include <kern/kern_types.h>
  55 #include <kern/host.h>
  56 #include <kern/task.h>
  57 #include <kern/zalloc.h>
  58 #include <kern/kalloc.h>
  59 #include <kern/assert.h>
  60
  61 #include <libkern/libkern.h>
  62
  63 #include <vm/vm_pageout.h>
  64 #include <vm/vm_map.h>
  65 #include <vm/vm_kern.h>
  66 #include <vm/vnode_pager.h>
  67 #include <vm/vm_protos.h>
  68
  69 extern thread_t current_act(void);
  70
  71 /*
  72  * temporary support for delayed instantiation
  73  * of default_pager
  74  */
  75 int default_pager_init_flag = 0;
  76
  77 struct bs_map           bs_port_table[MAX_BACKING_STORE] = {
  78         {0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  79         {0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  80         {0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  81         {0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  82         {0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
  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
  89 /* ###################################################### */
  90
  91
  92 /*
  93  *      Routine:        macx_backing_store_recovery
  94  *      Function:
  95  *              Syscall interface to set a tasks privilege
  96  *              level so that it is not subject to
  97  *              macx_backing_store_suspend
  98  */
  99 int
 100 macx_backing_store_recovery(
 101         struct macx_backing_store_recovery_args *args)
 102 {
 103         int             pid = args->pid;
 104         int             error;
 105         struct proc     *p =  current_proc();
 106         boolean_t       funnel_state;
 107
 108         funnel_state = thread_funnel_set(kernel_flock, TRUE);
 109         if ((error = suser(kauth_cred_get(), 0)))
 110                 goto backing_store_recovery_return;
 111
 112         /* for now restrict backing_store_recovery */
 113         /* usage to only present task */
 114         if(pid != proc_selfpid()) {
 115                 error = EINVAL;
 116                 goto backing_store_recovery_return;
 117         }
 118
 119         task_backing_store_privileged(p->task);
 120
 121 backing_store_recovery_return:
 122         (void) thread_funnel_set(kernel_flock, FALSE);
 123         return(error);
 124 }
 125
 126 /*
 127  *      Routine:        macx_backing_store_suspend
 128  *      Function:
 129  *              Syscall interface to stop new demand for
 130  *              backing store when backing store is low
 131  */
 132
 133 int
 134 macx_backing_store_suspend(
 135         struct macx_backing_store_suspend_args *args)
 136 {
 137         boolean_t       suspend = args->suspend;
 138         int             error;
 139         boolean_t       funnel_state;
 140
 141         funnel_state = thread_funnel_set(kernel_flock, TRUE);
 142         if ((error = suser(kauth_cred_get(), 0)))
 143                 goto backing_store_suspend_return;
 144
 145         vm_backing_store_disable(suspend);
 146
 147 backing_store_suspend_return:
 148         (void) thread_funnel_set(kernel_flock, FALSE);
 149         return(error);
 150 }
 151
 152 /*
 153  *      Routine:        macx_swapon
 154  *      Function:
 155  *              Syscall interface to add a file to backing store
 156  */
 157 int
 158 macx_swapon(
 159         struct macx_swapon_args *args)
 160 {
 161         int                     size = args->size;
 162         vnode_t                 vp = (vnode_t)NULL;
 163         struct nameidata        nd, *ndp;
 164         struct proc             *p =  current_proc();
 165         register int            error;
 166         kern_return_t           kr;
 167         mach_port_t             backing_store;
 168         memory_object_default_t default_pager;
 169         int                     i;
 170         boolean_t               funnel_state;
 171         off_t                   file_size;
 172         struct vfs_context      context;
 173
 174         context.vc_proc = p;
 175         context.vc_ucred = kauth_cred_get();
 176
 177         AUDIT_MACH_SYSCALL_ENTER(AUE_SWAPON);
 178         AUDIT_ARG(value, args->priority);
 179
 180         funnel_state = thread_funnel_set(kernel_flock, TRUE);
 181         ndp = &nd;
 182
 183         if ((error = suser(kauth_cred_get(), 0)))
 184                 goto swapon_bailout;
 185
 186         if(default_pager_init_flag == 0) {
 187                 start_def_pager(NULL);
 188                 default_pager_init_flag = 1;
 189         }
 190
 191         /*
 192          * Get a vnode for the paging area.
 193          */
 194         NDINIT(ndp, LOOKUP, FOLLOW | LOCKLEAF | AUDITVNPATH1,
 195                ((IS_64BIT_PROCESS(p)) ? UIO_USERSPACE64 : UIO_USERSPACE32),
 196                CAST_USER_ADDR_T(args->filename), &context);
 197
 198         if ((error = namei(ndp)))
 199                 goto swapon_bailout;
 200         nameidone(ndp);
 201         vp = ndp->ni_vp;
 202
 203         if (vp->v_type != VREG) {
 204                 error = EINVAL;
 205                 goto swapon_bailout;
 206         }
 207         UBCINFOCHECK("macx_swapon", vp);
 208
 209         /* get file size */
 210         if ((error = vnode_size(vp, &file_size, &context)) != 0)
 211                 goto swapon_bailout;
 212
 213         /* resize to desired size if it's too small */
 214         if ((file_size < (off_t)size) && ((error = vnode_setsize(vp, (off_t)size, 0, &context)) != 0))
 215                 goto swapon_bailout;
 216
 217         /* add new backing store to list */
 218         i = 0;
 219         while(bs_port_table[i].vp != 0) {
 220                 if(i == MAX_BACKING_STORE)
 221                         break;
 222                 i++;
 223         }
 224         if(i == MAX_BACKING_STORE) {
 225                 error = ENOMEM;
 226                 goto swapon_bailout;
 227         }
 228
 229         /* remember the vnode. This vnode has namei() reference */
 230         bs_port_table[i].vp = vp;
 231
 232         /*
 233          * Look to see if we are already paging to this file.
 234          */
 235         /* make certain the copy send of kernel call will work */
 236         default_pager = MEMORY_OBJECT_DEFAULT_NULL;
 237         kr = host_default_memory_manager(host_priv_self(), &default_pager, 0);
 238         if(kr != KERN_SUCCESS) {
 239            error = EAGAIN;
 240            bs_port_table[i].vp = 0;
 241            goto swapon_bailout;
 242         }
 243
 244         kr = default_pager_backing_store_create(default_pager,
 245                                         -1, /* default priority */
 246                                         0, /* default cluster size */
 247                                         &backing_store);
 248         memory_object_default_deallocate(default_pager);
 249
 250         if(kr != KERN_SUCCESS) {
 251            error = ENOMEM;
 252            bs_port_table[i].vp = 0;
 253            goto swapon_bailout;
 254         }
 255
 256         /*
 257          * NOTE: we are able to supply PAGE_SIZE here instead of
 258          *      an actual record size or block number because:
 259          *      a: we do not support offsets from the beginning of the
 260          *              file (allowing for non page size/record modulo offsets.
 261          *      b: because allow paging will be done modulo page size
 262          */
 263
 264         kr = default_pager_add_file(backing_store, (vnode_ptr_t) vp,
 265                                 PAGE_SIZE, (int)(file_size/PAGE_SIZE));
 266         if(kr != KERN_SUCCESS) {
 267            bs_port_table[i].vp = 0;
 268            if(kr == KERN_INVALID_ARGUMENT)
 269                 error = EINVAL;
 270            else
 271                 error = ENOMEM;
 272            goto swapon_bailout;
 273         }
 274         bs_port_table[i].bs = (void *)backing_store;
 275         error = 0;
 276
 277         /* Mark this vnode as being used for swapfile */
 278         SET(vp->v_flag, VSWAP);
 279
 280         ubc_setthreadcred(vp, p, current_thread());
 281
 282         /*
 283          * take a long term reference on the vnode to keep
 284          * vnreclaim() away from this vnode.
 285          */
 286         vnode_ref(vp);
 287
 288 swapon_bailout:
 289         if (vp) {
 290                 vnode_put(vp);
 291         }
 292         (void) thread_funnel_set(kernel_flock, FALSE);
 293         AUDIT_MACH_SYSCALL_EXIT(error);
 294         return(error);
 295 }
 296
 297 /*
 298  *      Routine:        macx_swapoff
 299  *      Function:
 300  *              Syscall interface to remove a file from backing store
 301  */
 302 int
 303 macx_swapoff(
 304         struct macx_swapoff_args *args)
 305 {
 306         __unused int    flags = args->flags;
 307         kern_return_t   kr;
 308         mach_port_t     backing_store;
 309
 310         struct vnode            *vp = 0;
 311         struct nameidata        nd, *ndp;
 312         struct proc             *p =  current_proc();
 313         int                     i;
 314         int                     error;
 315         boolean_t               funnel_state;
 316         struct vfs_context context;
 317
 318         context.vc_proc = p;
 319         context.vc_ucred = kauth_cred_get();
 320
 321         AUDIT_MACH_SYSCALL_ENTER(AUE_SWAPOFF);
 322
 323         funnel_state = thread_funnel_set(kernel_flock, TRUE);
 324         backing_store = NULL;
 325         ndp = &nd;
 326
 327         if ((error = suser(kauth_cred_get(), 0)))
 328                 goto swapoff_bailout;
 329
 330         /*
 331          * Get the vnode for the paging area.
 332          */
 333         NDINIT(ndp, LOOKUP, FOLLOW | LOCKLEAF | AUDITVNPATH1,
 334                ((IS_64BIT_PROCESS(p)) ? UIO_USERSPACE64 : UIO_USERSPACE32),
 335                CAST_USER_ADDR_T(args->filename), &context);
 336
 337         if ((error = namei(ndp)))
 338                 goto swapoff_bailout;
 339         nameidone(ndp);
 340         vp = ndp->ni_vp;
 341
 342         if (vp->v_type != VREG) {
 343                 error = EINVAL;
 344                 goto swapoff_bailout;
 345         }
 346
 347         for(i = 0; i < MAX_BACKING_STORE; i++) {
 348                 if(bs_port_table[i].vp == vp) {
 349                         break;
 350                 }
 351         }
 352         if (i == MAX_BACKING_STORE) {
 353                 error = EINVAL;
 354                 goto swapoff_bailout;
 355         }
 356         backing_store = (mach_port_t)bs_port_table[i].bs;
 357
 358         kr = default_pager_backing_store_delete(backing_store);
 359         switch (kr) {
 360                 case KERN_SUCCESS:
 361                         error = 0;
 362                         bs_port_table[i].vp = 0;
 363                         /* This vnode is no longer used for swapfile */
 364                         CLR(vp->v_flag, VSWAP);
 365
 366                         /* get rid of macx_swapon() "long term" reference */
 367                         vnode_rele(vp);
 368
 369                         break;
 370                 case KERN_FAILURE:
 371                         error = EAGAIN;
 372                         break;
 373                 default:
 374                         error = EAGAIN;
 375                         break;
 376         }
 377
 378 swapoff_bailout:
 379         /* get rid of macx_swapoff() namei() reference */
 380         if (vp)
 381                 vnode_put(vp);
 382
 383         (void) thread_funnel_set(kernel_flock, FALSE);
 384         AUDIT_MACH_SYSCALL_EXIT(error);
 385         return(error);
 386 }
 387
 388 /*
 389  *      Routine:        macx_swapinfo
 390  *      Function:
 391  *              Syscall interface to get general swap statistics
 392  */
 393 int
 394 macx_swapinfo(
 395         memory_object_size_t    *total_p,
 396         memory_object_size_t    *avail_p,
 397         vm_size_t               *pagesize_p,
 398         boolean_t               *encrypted_p)
 399 {
 400         int                     error;
 401         memory_object_default_t default_pager;
 402         default_pager_info_64_t dpi64;
 403         kern_return_t           kr;
 404
 405         error = 0;
 406
 407         /*
 408          * Get a handle on the default pager.
 409          */
 410         default_pager = MEMORY_OBJECT_DEFAULT_NULL;
 411         kr = host_default_memory_manager(host_priv_self(), &default_pager, 0);
 412         if (kr != KERN_SUCCESS) {
 413                 error = EAGAIN; /* XXX why EAGAIN ? */
 414                 goto done;
 415         }
 416         if (default_pager == MEMORY_OBJECT_DEFAULT_NULL) {
 417                 /*
 418                  * The default pager has not initialized yet,
 419                  * so it can't be using any swap space at all.
 420                  */
 421                 *total_p = 0;
 422                 *avail_p = 0;
 423                 *pagesize_p = 0;
 424                 *encrypted_p = FALSE;
 425                 goto done;
 426         }
 427
 428         /*
 429          * Get swap usage data from default pager.
 430          */
 431         kr = default_pager_info_64(default_pager, &dpi64);
 432         if (kr != KERN_SUCCESS) {
 433                 error = ENOTSUP;
 434                 goto done;
 435         }
 436
 437         /*
 438          * Provide default pager info to caller.
 439          */
 440         *total_p = dpi64.dpi_total_space;
 441         *avail_p = dpi64.dpi_free_space;
 442         *pagesize_p = dpi64.dpi_page_size;
 443         if (dpi64.dpi_flags & DPI_ENCRYPTED) {
 444                 *encrypted_p = TRUE;
 445         } else {
 446                 *encrypted_p = FALSE;
 447         }
 448
 449 done:
 450         if (default_pager != MEMORY_OBJECT_DEFAULT_NULL) {
 451                 /* release our handle on default pager */
 452                 memory_object_default_deallocate(default_pager);
 453         }
 454         return error;
 455 }