kernel/vserver/context.c

   1 /*
   2  *  linux/kernel/vserver/context.c
   3  *
   4  *  Virtual Server: Context Support
   5  *
   6  *  Copyright (C) 2003-2005  Herbert Pötzl
   7  *
   8  *  V0.01  context helper
   9  *  V0.02  vx_ctx_kill syscall command
  10  *  V0.03  replaced context_info calls
  11  *  V0.04  redesign of struct (de)alloc
  12  *  V0.05  rlimit basic implementation
  13  *  V0.06  task_xid and info commands
  14  *  V0.07  context flags and caps
  15  *  V0.08  switch to RCU based hash
  16  *  V0.09  revert to non RCU for now
  17  *  V0.10  and back to working RCU hash
  18  *  V0.11  and back to locking again
  19  *
  20  */
  21
  22 #include <linux/config.h>
  23 #include <linux/slab.h>
  24 #include <linux/types.h>
  25 #include <linux/namespace.h>
  26
  27 #include <linux/sched.h>
  28 #include <linux/vserver/network.h>
  29 #include <linux/vserver/legacy.h>
  30 #include <linux/vserver/limit.h>
  31 #include <linux/vserver/debug.h>
  32
  33 #include <linux/vs_context.h>
  34 #include <linux/vserver/context_cmd.h>
  35
  36 #include <linux/err.h>
  37 #include <asm/errno.h>
  38
  39 #include "cvirt_init.h"
  40 #include "limit_init.h"
  41 #include "sched_init.h"
  42
  43
  44 /*      __alloc_vx_info()
  45
  46         * allocate an initialized vx_info struct
  47         * doesn't make it visible (hash)                        */
  48
  49 static struct vx_info *__alloc_vx_info(xid_t xid)
  50 {
  51         struct vx_info *new = NULL;
  52
  53         vxdprintk(VXD_CBIT(xid, 0), "alloc_vx_info(%d)*", xid);
  54
  55         /* would this benefit from a slab cache? */
  56         new = kmalloc(sizeof(struct vx_info), GFP_KERNEL);
  57         if (!new)
  58                 return 0;
  59
  60         memset (new, 0, sizeof(struct vx_info));
  61         new->vx_id = xid;
  62         // INIT_RCU_HEAD(&new->vx_rcu);
  63         INIT_HLIST_NODE(&new->vx_hlist);
  64         atomic_set(&new->vx_usecnt, 0);
  65         atomic_set(&new->vx_tasks, 0);
  66         new->vx_parent = NULL;
  67         new->vx_state = 0;
  68         new->vx_lock = SPIN_LOCK_UNLOCKED;
  69         init_waitqueue_head(&new->vx_wait);
  70
  71         /* rest of init goes here */
  72         vx_info_init_limit(&new->limit);
  73         vx_info_init_sched(&new->sched);
  74         vx_info_init_cvirt(&new->cvirt);
  75         vx_info_init_cacct(&new->cacct);
  76
  77
  78         new->vx_flags = VXF_STATE_SETUP|VXF_STATE_INIT;
  79         new->vx_bcaps = CAP_INIT_EFF_SET;
  80         new->vx_ccaps = 0;
  81
  82         vxdprintk(VXD_CBIT(xid, 0),
  83                 "alloc_vx_info(%d) = %p", xid, new);
  84         vxh_alloc_vx_info(new);
  85         return new;
  86 }
  87
  88 /*      __dealloc_vx_info()
  89
  90         * final disposal of vx_info                             */
  91
  92 static void __dealloc_vx_info(struct vx_info *vxi)
  93 {
  94         vxdprintk(VXD_CBIT(xid, 0),
  95                 "dealloc_vx_info(%p)", vxi);
  96         vxh_dealloc_vx_info(vxi);
  97
  98         vxi->vx_hlist.next = LIST_POISON1;
  99         vxi->vx_id = -1;
 100
 101         vx_info_exit_limit(&vxi->limit);
 102         vx_info_exit_sched(&vxi->sched);
 103         vx_info_exit_cvirt(&vxi->cvirt);
 104         vx_info_exit_cacct(&vxi->cacct);
 105
 106         vxi->vx_state |= VXS_RELEASED;
 107         kfree(vxi);
 108 }
 109
 110 void __shutdown_vx_info(struct vx_info *vxi)
 111 {
 112         struct namespace *namespace;
 113         struct fs_struct *fs;
 114
 115         might_sleep();
 116
 117         vxi->vx_state |= VXS_SHUTDOWN;
 118         vs_state_change(vxi, VSC_SHUTDOWN);
 119
 120         namespace = xchg(&vxi->vx_namespace, NULL);
 121         if (namespace)
 122                 put_namespace(namespace);
 123
 124         fs = xchg(&vxi->vx_fs, NULL);
 125         if (fs)
 126                 put_fs_struct(fs);
 127 }
 128
 129 /* exported stuff */
 130
 131 void free_vx_info(struct vx_info *vxi)
 132 {
 133         /* context shutdown is mandatory */
 134         // BUG_ON(vxi->vx_state != VXS_SHUTDOWN);
 135
 136         BUG_ON(atomic_read(&vxi->vx_usecnt));
 137         BUG_ON(atomic_read(&vxi->vx_tasks));
 138
 139         BUG_ON(vx_info_state(vxi, VXS_HASHED));
 140         // BUG_ON(!vx_state(vxi, VXS_DEFUNCT));
 141
 142         BUG_ON(vxi->vx_namespace);
 143         BUG_ON(vxi->vx_fs);
 144
 145         __dealloc_vx_info(vxi);
 146 }
 147
 148
 149 /*      hash table for vx_info hash */
 150
 151 #define VX_HASH_SIZE    13
 152
 153 struct hlist_head vx_info_hash[VX_HASH_SIZE];
 154
 155 static spinlock_t vx_info_hash_lock = SPIN_LOCK_UNLOCKED;
 156
 157
 158 static inline unsigned int __hashval(xid_t xid)
 159 {
 160         return (xid % VX_HASH_SIZE);
 161 }
 162
 163
 164
 165 /*      __hash_vx_info()
 166
 167         * add the vxi to the global hash table
 168         * requires the hash_lock to be held                     */
 169
 170 static inline void __hash_vx_info(struct vx_info *vxi)
 171 {
 172         struct hlist_head *head;
 173
 174         vxd_assert_lock(&vx_info_hash_lock);
 175         vxdprintk(VXD_CBIT(xid, 4),
 176                 "__hash_vx_info: %p[#%d]", vxi, vxi->vx_id);
 177         vxh_hash_vx_info(vxi);
 178
 179         /* context must not be hashed */
 180         BUG_ON(vxi->vx_state & VXS_HASHED);
 181
 182         vxi->vx_state |= VXS_HASHED;
 183         head = &vx_info_hash[__hashval(vxi->vx_id)];
 184         hlist_add_head(&vxi->vx_hlist, head);
 185 }
 186
 187 /*      __unhash_vx_info()
 188
 189         * remove the vxi from the global hash table
 190         * requires the hash_lock to be held                     */
 191
 192 static inline void __unhash_vx_info(struct vx_info *vxi)
 193 {
 194         vxd_assert_lock(&vx_info_hash_lock);
 195         vxdprintk(VXD_CBIT(xid, 4),
 196                 "__unhash_vx_info: %p[#%d]", vxi, vxi->vx_id);
 197         vxh_unhash_vx_info(vxi);
 198
 199         /* maybe warn on that? */
 200         if (!(vxi->vx_state & VXS_HASHED))
 201                 return;
 202
 203         vxi->vx_state &= ~VXS_HASHED;
 204         hlist_del(&vxi->vx_hlist);
 205 }
 206
 207
 208 /*      __lookup_vx_info()
 209
 210         * requires the hash_lock to be held
 211         * doesn't increment the vx_refcnt                       */
 212
 213 static inline struct vx_info *__lookup_vx_info(xid_t xid)
 214 {
 215         struct hlist_head *head = &vx_info_hash[__hashval(xid)];
 216         struct hlist_node *pos;
 217         struct vx_info *vxi;
 218
 219         vxd_assert_lock(&vx_info_hash_lock);
 220         hlist_for_each(pos, head) {
 221                 vxi = hlist_entry(pos, struct vx_info, vx_hlist);
 222
 223                 if (vxi->vx_id == xid)
 224                         goto found;
 225         }
 226         vxi = NULL;
 227 found:
 228         vxdprintk(VXD_CBIT(xid, 0),
 229                 "__lookup_vx_info(#%u): %p[#%u]",
 230                 xid, vxi, vxi?vxi->vx_id:0);
 231         vxh_lookup_vx_info(xid, vxi);
 232         return vxi;
 233 }
 234
 235
 236 /*      __vx_dynamic_id()
 237
 238         * find unused dynamic xid
 239         * requires the hash_lock to be held                     */
 240
 241 static inline xid_t __vx_dynamic_id(void)
 242 {
 243         static xid_t seq = MAX_S_CONTEXT;
 244         xid_t barrier = seq;
 245
 246         vxd_assert_lock(&vx_info_hash_lock);
 247         do {
 248                 if (++seq > MAX_S_CONTEXT)
 249                         seq = MIN_D_CONTEXT;
 250                 if (!__lookup_vx_info(seq)) {
 251                         vxdprintk(VXD_CBIT(xid, 4),
 252                                 "__vx_dynamic_id: [#%d]", seq);
 253                         return seq;
 254                 }
 255         } while (barrier != seq);
 256         return 0;
 257 }
 258
 259 #ifdef  CONFIG_VSERVER_LEGACY
 260
 261 /*      __loc_vx_info()
 262
 263         * locate or create the requested context
 264         * get() it and if new hash it                           */
 265
 266 static struct vx_info * __loc_vx_info(int id, int *err)
 267 {
 268         struct vx_info *new, *vxi = NULL;
 269
 270         vxdprintk(VXD_CBIT(xid, 1), "loc_vx_info(%d)*", id);
 271
 272         if (!(new = __alloc_vx_info(id))) {
 273                 *err = -ENOMEM;
 274                 return NULL;
 275         }
 276
 277         /* required to make dynamic xids unique */
 278         spin_lock(&vx_info_hash_lock);
 279
 280         /* dynamic context requested */
 281         if (id == VX_DYNAMIC_ID) {
 282                 id = __vx_dynamic_id();
 283                 if (!id) {
 284                         printk(KERN_ERR "no dynamic context available.\n");
 285                         goto out_unlock;
 286                 }
 287                 new->vx_id = id;
 288         }
 289         /* existing context requested */
 290         else if ((vxi = __lookup_vx_info(id))) {
 291                 /* context in setup is not available */
 292                 if (vxi->vx_flags & VXF_STATE_SETUP) {
 293                         vxdprintk(VXD_CBIT(xid, 0),
 294                                 "loc_vx_info(%d) = %p (not available)", id, vxi);
 295                         vxi = NULL;
 296                         *err = -EBUSY;
 297                 } else {
 298                         vxdprintk(VXD_CBIT(xid, 0),
 299                                 "loc_vx_info(%d) = %p (found)", id, vxi);
 300                         get_vx_info(vxi);
 301                         *err = 0;
 302                 }
 303                 goto out_unlock;
 304         }
 305
 306         /* new context requested */
 307         vxdprintk(VXD_CBIT(xid, 0),
 308                 "loc_vx_info(%d) = %p (new)", id, new);
 309         __hash_vx_info(get_vx_info(new));
 310         vxi = new, new = NULL;
 311         *err = 1;
 312
 313 out_unlock:
 314         spin_unlock(&vx_info_hash_lock);
 315         vxh_loc_vx_info(id, vxi);
 316         if (new)
 317                 __dealloc_vx_info(new);
 318         return vxi;
 319 }
 320
 321 #endif
 322
 323 /*      __create_vx_info()
 324
 325         * create the requested context
 326         * get() it and hash it                                  */
 327
 328 static struct vx_info * __create_vx_info(int id)
 329 {
 330         struct vx_info *new, *vxi = NULL;
 331
 332         vxdprintk(VXD_CBIT(xid, 1), "create_vx_info(%d)*", id);
 333
 334         if (!(new = __alloc_vx_info(id))) {
 335                 return ERR_PTR(-ENOMEM);
 336         }
 337
 338         /* required to make dynamic xids unique */
 339         spin_lock(&vx_info_hash_lock);
 340
 341         /* dynamic context requested */
 342         if (id == VX_DYNAMIC_ID) {
 343                 id = __vx_dynamic_id();
 344                 if (!id) {
 345                         printk(KERN_ERR "no dynamic context available.\n");
 346                         vxi = ERR_PTR(-EAGAIN);
 347                         goto out_unlock;
 348                 }
 349                 new->vx_id = id;
 350         }
 351         /* existing context requested */
 352         else if ((vxi = __lookup_vx_info(id))) {
 353                 vxdprintk(VXD_CBIT(xid, 0),
 354                         "create_vx_info(%d) = %p (already there)", id, vxi);
 355                 if (vx_info_flags(vxi, VXF_STATE_SETUP, 0))
 356                         vxi = ERR_PTR(-EBUSY);
 357                 else
 358                         vxi = ERR_PTR(-EEXIST);
 359                 goto out_unlock;
 360         }
 361         /* dynamic xid creation blocker */
 362         else if (id >= MIN_D_CONTEXT) {
 363                 vxdprintk(VXD_CBIT(xid, 0),
 364                         "create_vx_info(%d) (dynamic rejected)", id);
 365                 vxi = ERR_PTR(-EINVAL);
 366                 goto out_unlock;
 367         }
 368
 369         /* new context requested */
 370         vxdprintk(VXD_CBIT(xid, 0),
 371                 "create_vx_info(%d) = %p (new)", id, new);
 372         __hash_vx_info(get_vx_info(new));
 373         vxi = new, new = NULL;
 374
 375 out_unlock:
 376         spin_unlock(&vx_info_hash_lock);
 377         vxh_create_vx_info(id, IS_ERR(vxi)?NULL:vxi);
 378         if (new)
 379                 __dealloc_vx_info(new);
 380         return vxi;
 381 }
 382
 383
 384 /*      exported stuff                                          */
 385
 386
 387 void unhash_vx_info(struct vx_info *vxi)
 388 {
 389         __shutdown_vx_info(vxi);
 390         spin_lock(&vx_info_hash_lock);
 391         __unhash_vx_info(vxi);
 392         spin_unlock(&vx_info_hash_lock);
 393         __wakeup_vx_info(vxi);
 394 }
 395
 396
 397 /*      locate_vx_info()
 398
 399         * search for a vx_info and get() it
 400         * negative id means current                             */
 401
 402 struct vx_info *locate_vx_info(int id)
 403 {
 404         struct vx_info *vxi = NULL;
 405
 406         if (id < 0) {
 407                 vxi = get_vx_info(current->vx_info);
 408         } else if (id > 1) {
 409                 spin_lock(&vx_info_hash_lock);
 410                 vxi = get_vx_info(__lookup_vx_info(id));
 411                 spin_unlock(&vx_info_hash_lock);
 412         }
 413         return vxi;
 414 }
 415
 416 /*      xid_is_hashed()
 417
 418         * verify that xid is still hashed                       */
 419
 420 int xid_is_hashed(xid_t xid)
 421 {
 422         int hashed;
 423
 424         spin_lock(&vx_info_hash_lock);
 425         hashed = (__lookup_vx_info(xid) != NULL);
 426         spin_unlock(&vx_info_hash_lock);
 427         return hashed;
 428 }
 429
 430 #ifdef  CONFIG_VSERVER_LEGACY
 431
 432 struct vx_info *locate_or_create_vx_info(int id)
 433 {
 434         int err;
 435
 436         return __loc_vx_info(id, &err);
 437 }
 438
 439 #endif
 440
 441 #ifdef  CONFIG_PROC_FS
 442
 443 int get_xid_list(int index, unsigned int *xids, int size)
 444 {
 445         int hindex, nr_xids = 0;
 446
 447         for (hindex = 0; hindex < VX_HASH_SIZE; hindex++) {
 448                 struct hlist_head *head = &vx_info_hash[hindex];
 449                 struct hlist_node *pos;
 450
 451                 spin_lock(&vx_info_hash_lock);
 452                 hlist_for_each(pos, head) {
 453                         struct vx_info *vxi;
 454
 455                         if (--index > 0)
 456                                 continue;
 457
 458                         vxi = hlist_entry(pos, struct vx_info, vx_hlist);
 459                         xids[nr_xids] = vxi->vx_id;
 460                         if (++nr_xids >= size) {
 461                                 spin_unlock(&vx_info_hash_lock);
 462                                 goto out;
 463                         }
 464                 }
 465                 /* keep the lock time short */
 466                 spin_unlock(&vx_info_hash_lock);
 467         }
 468 out:
 469         return nr_xids;
 470 }
 471 #endif
 472
 473 int vx_migrate_user(struct task_struct *p, struct vx_info *vxi)
 474 {
 475         struct user_struct *new_user, *old_user;
 476
 477         if (!p || !vxi)
 478                 BUG();
 479         new_user = alloc_uid(vxi->vx_id, p->uid);
 480         if (!new_user)
 481                 return -ENOMEM;
 482
 483         old_user = p->user;
 484         if (new_user != old_user) {
 485                 atomic_inc(&new_user->processes);
 486                 atomic_dec(&old_user->processes);
 487                 p->user = new_user;
 488         }
 489         free_uid(old_user);
 490         return 0;
 491 }
 492
 493 void vx_mask_bcaps(struct task_struct *p)
 494 {
 495         struct vx_info *vxi = p->vx_info;
 496
 497         p->cap_effective &= vxi->vx_bcaps;
 498         p->cap_inheritable &= vxi->vx_bcaps;
 499         p->cap_permitted &= vxi->vx_bcaps;
 500 }
 501
 502
 503 #include <linux/file.h>
 504
 505 static int vx_openfd_task(struct task_struct *tsk)
 506 {
 507         struct files_struct *files = tsk->files;
 508         const unsigned long *bptr;
 509         int count, total;
 510
 511         spin_lock(&files->file_lock);
 512         bptr = files->open_fds->fds_bits;
 513         count = files->max_fds / (sizeof(unsigned long) * 8);
 514         for (total = 0; count > 0; count--) {
 515                 if (*bptr)
 516                         total += hweight_long(*bptr);
 517                 bptr++;
 518         }
 519         spin_unlock(&files->file_lock);
 520         return total;
 521 }
 522
 523 /*
 524  *      migrate task to new context
 525  *      gets vxi, puts old_vxi on change
 526  */
 527
 528 int vx_migrate_task(struct task_struct *p, struct vx_info *vxi)
 529 {
 530         struct vx_info *old_vxi;
 531         int ret = 0;
 532
 533         if (!p || !vxi)
 534                 BUG();
 535
 536         old_vxi = task_get_vx_info(p);
 537         if (old_vxi == vxi)
 538                 goto out;
 539
 540         vxdprintk(VXD_CBIT(xid, 5),
 541                 "vx_migrate_task(%p,%p[#%d.%d])", p, vxi,
 542                 vxi->vx_id, atomic_read(&vxi->vx_usecnt));
 543
 544         if (!(ret = vx_migrate_user(p, vxi))) {
 545                 int openfd;
 546
 547                 task_lock(p);
 548                 openfd = vx_openfd_task(p);
 549
 550                 if (old_vxi) {
 551                         atomic_dec(&old_vxi->cvirt.nr_threads);
 552                         atomic_dec(&old_vxi->cvirt.nr_running);
 553                         atomic_dec(&old_vxi->limit.rcur[RLIMIT_NPROC]);
 554                         /* FIXME: what about the struct files here? */
 555                         atomic_sub(openfd, &old_vxi->limit.rcur[VLIMIT_OPENFD]);
 556                 }
 557                 atomic_inc(&vxi->cvirt.nr_threads);
 558                 atomic_inc(&vxi->cvirt.nr_running);
 559                 atomic_inc(&vxi->limit.rcur[RLIMIT_NPROC]);
 560                 /* FIXME: what about the struct files here? */
 561                 atomic_add(openfd, &vxi->limit.rcur[VLIMIT_OPENFD]);
 562
 563                 if (old_vxi) {
 564                         release_vx_info(old_vxi, p);
 565                         clr_vx_info(&p->vx_info);
 566                 }
 567                 claim_vx_info(vxi, p);
 568                 set_vx_info(&p->vx_info, vxi);
 569                 p->xid = vxi->vx_id;
 570
 571                 vxdprintk(VXD_CBIT(xid, 5),
 572                         "moved task %p into vxi:%p[#%d]",
 573                         p, vxi, vxi->vx_id);
 574
 575                 vx_mask_bcaps(p);
 576                 task_unlock(p);
 577         }
 578 out:
 579         put_vx_info(old_vxi);
 580         return ret;
 581 }
 582
 583 int vx_set_init(struct vx_info *vxi, struct task_struct *p)
 584 {
 585         if (!vxi)
 586                 return -EINVAL;
 587         if (vxi->vx_initpid)
 588                 return -EPERM;
 589
 590         vxdprintk(VXD_CBIT(xid, 6),
 591                 "vx_set_init(%p[#%d],%p[#%d,%d,%d])",
 592                 vxi, vxi->vx_id, p, p->xid, p->pid, p->tgid);
 593
 594         vxi->vx_initpid = p->tgid;
 595         return 0;
 596 }
 597
 598
 599 /* vserver syscall commands below here */
 600
 601 /* taks xid and vx_info functions */
 602
 603 #include <asm/uaccess.h>
 604
 605
 606 int vc_task_xid(uint32_t id, void __user *data)
 607 {
 608         xid_t xid;
 609
 610         if (id) {
 611                 struct task_struct *tsk;
 612
 613                 if (!vx_check(0, VX_ADMIN|VX_WATCH))
 614                         return -EPERM;
 615
 616                 read_lock(&tasklist_lock);
 617                 tsk = find_task_by_real_pid(id);
 618                 xid = (tsk) ? tsk->xid : -ESRCH;
 619                 read_unlock(&tasklist_lock);
 620         }
 621         else
 622                 xid = vx_current_xid();
 623         return xid;
 624 }
 625
 626
 627 int vc_vx_info(uint32_t id, void __user *data)
 628 {
 629         struct vx_info *vxi;
 630         struct vcmd_vx_info_v0 vc_data;
 631
 632         if (!vx_check(0, VX_ADMIN))
 633                 return -ENOSYS;
 634         if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RESOURCE))
 635                 return -EPERM;
 636
 637         vxi = locate_vx_info(id);
 638         if (!vxi)
 639                 return -ESRCH;
 640
 641         vc_data.xid = vxi->vx_id;
 642         vc_data.initpid = vxi->vx_initpid;
 643         put_vx_info(vxi);
 644
 645         if (copy_to_user (data, &vc_data, sizeof(vc_data)))
 646                 return -EFAULT;
 647         return 0;
 648 }
 649
 650
 651 /* context functions */
 652
 653 int vc_ctx_create(uint32_t xid, void __user *data)
 654 {
 655         struct vx_info *new_vxi;
 656         int ret;
 657
 658         if (!capable(CAP_SYS_ADMIN))
 659                 return -EPERM;
 660
 661         if ((xid > MAX_S_CONTEXT) && (xid != VX_DYNAMIC_ID))
 662                 return -EINVAL;
 663
 664         if (xid < 2)
 665                 return -EINVAL;
 666
 667         new_vxi = __create_vx_info(xid);
 668         if (IS_ERR(new_vxi))
 669                 return PTR_ERR(new_vxi);
 670
 671         vs_state_change(new_vxi, VSC_STARTUP);
 672         ret = new_vxi->vx_id;
 673         vx_migrate_task(current, new_vxi);
 674         /* if this fails, we might end up with a hashed vx_info */
 675         put_vx_info(new_vxi);
 676         return ret;
 677 }
 678
 679
 680 int vc_ctx_migrate(uint32_t id, void __user *data)
 681 {
 682         struct vx_info *vxi;
 683
 684         if (!capable(CAP_SYS_ADMIN))
 685                 return -EPERM;
 686
 687         /* dirty hack until Spectator becomes a cap */
 688         if (id == 1) {
 689                 current->xid = 1;
 690                 return 0;
 691         }
 692
 693         vxi = locate_vx_info(id);
 694         if (!vxi)
 695                 return -ESRCH;
 696         vx_migrate_task(current, vxi);
 697         put_vx_info(vxi);
 698         return 0;
 699 }
 700
 701
 702 int vc_get_cflags(uint32_t id, void __user *data)
 703 {
 704         struct vx_info *vxi;
 705         struct vcmd_ctx_flags_v0 vc_data;
 706
 707         if (!capable(CAP_SYS_ADMIN))
 708                 return -EPERM;
 709
 710         vxi = locate_vx_info(id);
 711         if (!vxi)
 712                 return -ESRCH;
 713
 714         vc_data.flagword = vxi->vx_flags;
 715
 716         /* special STATE flag handling */
 717         vc_data.mask = vx_mask_flags(~0UL, vxi->vx_flags, VXF_ONE_TIME);
 718
 719         put_vx_info(vxi);
 720
 721         if (copy_to_user (data, &vc_data, sizeof(vc_data)))
 722                 return -EFAULT;
 723         return 0;
 724 }
 725
 726 int vc_set_cflags(uint32_t id, void __user *data)
 727 {
 728         struct vx_info *vxi;
 729         struct vcmd_ctx_flags_v0 vc_data;
 730         uint64_t mask, trigger;
 731
 732         if (!capable(CAP_SYS_ADMIN))
 733                 return -EPERM;
 734         if (copy_from_user (&vc_data, data, sizeof(vc_data)))
 735                 return -EFAULT;
 736
 737         vxi = locate_vx_info(id);
 738         if (!vxi)
 739                 return -ESRCH;
 740
 741         /* special STATE flag handling */
 742         mask = vx_mask_mask(vc_data.mask, vxi->vx_flags, VXF_ONE_TIME);
 743         trigger = (mask & vxi->vx_flags) ^ (mask & vc_data.flagword);
 744
 745         if (trigger & VXF_STATE_SETUP)
 746                 vx_mask_bcaps(current);
 747         if (trigger & VXF_STATE_INIT)
 748                 if (vxi == current->vx_info)
 749                         vx_set_init(vxi, current);
 750
 751         vxi->vx_flags = vx_mask_flags(vxi->vx_flags,
 752                 vc_data.flagword, mask);
 753         put_vx_info(vxi);
 754         return 0;
 755 }
 756
 757 int vc_get_ccaps(uint32_t id, void __user *data)
 758 {
 759         struct vx_info *vxi;
 760         struct vcmd_ctx_caps_v0 vc_data;
 761
 762         if (!capable(CAP_SYS_ADMIN))
 763                 return -EPERM;
 764
 765         vxi = locate_vx_info(id);
 766         if (!vxi)
 767                 return -ESRCH;
 768
 769         vc_data.bcaps = vxi->vx_bcaps;
 770         vc_data.ccaps = vxi->vx_ccaps;
 771         vc_data.cmask = ~0UL;
 772         put_vx_info(vxi);
 773
 774         if (copy_to_user (data, &vc_data, sizeof(vc_data)))
 775                 return -EFAULT;
 776         return 0;
 777 }
 778
 779 int vc_set_ccaps(uint32_t id, void __user *data)
 780 {
 781         struct vx_info *vxi;
 782         struct vcmd_ctx_caps_v0 vc_data;
 783
 784         if (!capable(CAP_SYS_ADMIN))
 785                 return -EPERM;
 786         if (copy_from_user (&vc_data, data, sizeof(vc_data)))
 787                 return -EFAULT;
 788
 789         vxi = locate_vx_info(id);
 790         if (!vxi)
 791                 return -ESRCH;
 792
 793         vxi->vx_bcaps &= vc_data.bcaps;
 794         vxi->vx_ccaps = vx_mask_flags(vxi->vx_ccaps,
 795                 vc_data.ccaps, vc_data.cmask);
 796         put_vx_info(vxi);
 797         return 0;
 798 }
 799
 800 #include <linux/module.h>
 801
 802 EXPORT_SYMBOL_GPL(free_vx_info);
 803