sys/vfs/devfs/devfs_rules.c

   1 /*
   2  * Copyright (c) 2009 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Alex Hornung <ahornung@gmail.com>
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34 #include <sys/param.h>
  35 #include <sys/systm.h>
  36 #include <sys/kernel.h>
  37 #include <sys/types.h>
  38 #include <sys/param.h>
  39 #include <sys/ioccom.h>
  40 #include <sys/lock.h>
  41 #include <sys/spinlock2.h>
  42 #include <sys/fcntl.h>
  43 #include <sys/device.h>
  44 #include <sys/mount.h>
  45 #include <sys/devfs.h>
  46 #include <sys/devfs_rules.h>
  47
  48 MALLOC_DECLARE(M_DEVFS);
  49
  50 #if 0
  51 static int WildCmp(const char *w, const char *s);
  52 #endif
  53 static int WildCaseCmp(const char *w, const char *s);
  54 static int wildCmp(const char **mary, int d, const char *w, const char *s);
  55 static int wildCaseCmp(const char **mary, int d, const char *w, const char *s);
  56
  57 static d_open_t      devfs_dev_open;
  58 static d_close_t     devfs_dev_close;
  59 static d_ioctl_t     devfs_dev_ioctl;
  60
  61 static struct devfs_rule *devfs_rule_alloc(struct devfs_rule_ioctl *);
  62 static void devfs_rule_free(struct devfs_rule *);
  63 static void devfs_rule_insert(struct devfs_rule_ioctl *);
  64 static void devfs_rule_remove(struct devfs_rule *);
  65 static void devfs_rule_clear(struct devfs_rule_ioctl *);
  66 static void devfs_rule_create_link(struct devfs_node *, struct devfs_rule *);
  67 static int devfs_rule_checkname(struct devfs_rule *, struct devfs_node *);
  68
  69 static struct objcache  *devfs_rule_cache;
  70 static struct lock              devfs_rule_lock;
  71
  72 static struct objcache_malloc_args devfs_rule_malloc_args = {
  73         sizeof(struct devfs_rule), M_DEVFS };
  74
  75 static cdev_t devfs_dev;
  76 static struct devfs_rule_head devfs_rule_list =
  77                 TAILQ_HEAD_INITIALIZER(devfs_rule_list);
  78
  79 static struct dev_ops devfs_dev_ops = {
  80         { "devfs", 0, 0 },
  81         .d_open = devfs_dev_open,
  82         .d_close = devfs_dev_close,
  83         .d_ioctl = devfs_dev_ioctl
  84 };
  85
  86
  87 static struct devfs_rule *
  88 devfs_rule_alloc(struct devfs_rule_ioctl *templ)
  89 {
  90         struct devfs_rule *rule;
  91         size_t len;
  92
  93         rule = objcache_get(devfs_rule_cache, M_WAITOK);
  94         memset(rule, 0, sizeof(struct devfs_rule));
  95
  96         len = strlen(templ->mntpoint);
  97         if (len > 0) {
  98                 rule->mntpoint = kstrdup(templ->mntpoint, M_DEVFS);
  99                 rule->mntpointlen = len;
 100         }
 101
 102         if (templ->rule_type == DEVFS_RULE_NAME) {
 103                 len = strlen(templ->name);
 104                 if (len > 0) {
 105                         rule->name = kstrdup(templ->name, M_DEVFS);
 106                         rule->namlen = len;
 107                 }
 108         }
 109
 110         if (templ->rule_cmd == DEVFS_RULE_LINK) {
 111                 len = strlen(templ->linkname);
 112                 if (len > 0) {
 113                         rule->linkname = kstrdup(templ->linkname, M_DEVFS);
 114                         rule->linknamlen = len;
 115                 }
 116         }
 117
 118         rule->rule_type = templ->rule_type;
 119         rule->rule_cmd = templ->rule_cmd;
 120         rule->dev_type = templ->dev_type;
 121         rule->mode = templ->mode;
 122         rule->uid = templ->uid;
 123         rule->gid = templ->gid;
 124
 125         return rule;
 126 }
 127
 128
 129 static void
 130 devfs_rule_free(struct devfs_rule *rule)
 131 {
 132         if (rule->mntpoint != NULL) {
 133                 kfree(rule->mntpoint, M_DEVFS);
 134         }
 135
 136         if (rule->name != NULL) {
 137                 kfree(rule->name, M_DEVFS);
 138         }
 139
 140         if (rule->linkname != NULL) {
 141                 kfree(rule->linkname, M_DEVFS);
 142         }
 143         objcache_put(devfs_rule_cache, rule);
 144 }
 145
 146
 147 static void
 148 devfs_rule_insert(struct devfs_rule_ioctl *templ)
 149 {
 150         struct devfs_rule *rule;
 151
 152         rule = devfs_rule_alloc(templ);
 153
 154         lockmgr(&devfs_rule_lock, LK_EXCLUSIVE);
 155         TAILQ_INSERT_TAIL(&devfs_rule_list, rule, link);
 156         lockmgr(&devfs_rule_lock, LK_RELEASE);
 157 }
 158
 159
 160 static void
 161 devfs_rule_remove(struct devfs_rule *rule)
 162 {
 163         TAILQ_REMOVE(&devfs_rule_list, rule, link);
 164         devfs_rule_free(rule);
 165 }
 166
 167
 168 static void
 169 devfs_rule_clear(struct devfs_rule_ioctl *templ)
 170 {
 171         struct devfs_rule *rule1, *rule2;
 172         size_t  mntpointlen = strlen(templ->mntpoint);
 173
 174         lockmgr(&devfs_rule_lock, LK_EXCLUSIVE);
 175         TAILQ_FOREACH_MUTABLE(rule1, &devfs_rule_list, link, rule2) {
 176                 if ((templ->mntpoint[0] == '*') ||
 177                         ( (mntpointlen == rule1->mntpointlen) &&
 178                           (!memcmp(templ->mntpoint, rule1->mntpoint, mntpointlen)) )) {
 179                         devfs_rule_remove(rule1);
 180                 }
 181         }
 182         lockmgr(&devfs_rule_lock, LK_RELEASE);
 183 }
 184
 185
 186 void *
 187 devfs_rule_reset_node(struct devfs_node *node, void *unused)
 188 {
 189         /*
 190          * Don't blindly unhide all devices, some, like unix98 pty masters,
 191          * haven't been hidden by a rule.
 192          */
 193         if (node->flags & DEVFS_RULE_HIDDEN)
 194                 node->flags &= ~(DEVFS_HIDDEN | DEVFS_RULE_HIDDEN);
 195
 196         if ((node->node_type == Plink) && (node->flags & DEVFS_RULE_CREATED)) {
 197                 KKASSERT(node->link_target);
 198                 node->flags &= ~DEVFS_RULE_CREATED;
 199                 --node->link_target->nlinks;
 200                 devfs_gc(node);
 201         } else if ((node->node_type == Pdev) && (node->d_dev)) {
 202                 node->uid = node->d_dev->si_uid;
 203                 node->gid = node->d_dev->si_gid;
 204                 node->mode = node->d_dev->si_perms;
 205         }
 206
 207         return NULL;
 208 }
 209
 210 static void
 211 devfs_rule_create_link(struct devfs_node *node, struct devfs_rule *rule)
 212 {
 213         size_t len = 0;
 214         char *path = NULL;
 215         char *name, name_buf[PATH_MAX], buf[PATH_MAX];
 216
 217         if (rule->name[rule->namlen-1] == '*') {
 218                 devfs_resolve_name_path(rule->name, name_buf, &path, &name);
 219                 len = strlen(name);
 220                 --len;
 221                 ksnprintf(buf, sizeof(buf), "%s%s",
 222                     rule->linkname, node->d_dir.d_name+len);
 223                 devfs_alias_create(buf, node, 1);
 224         } else {
 225                 devfs_alias_create(rule->linkname, node, 1);
 226         }
 227 }
 228
 229 void *
 230 devfs_rule_check_apply(struct devfs_node *node, void *unused)
 231 {
 232         struct devfs_rule *rule;
 233         struct mount *mp = node->mp;
 234         int locked = 0;
 235
 236         /* Check if it is locked already. if not, we acquire the devfs lock */
 237         if (!(lockstatus(&devfs_rule_lock, curthread)) == LK_EXCLUSIVE) {
 238                 lockmgr(&devfs_rule_lock, LK_EXCLUSIVE);
 239                 locked = 1;
 240         }
 241
 242         TAILQ_FOREACH(rule, &devfs_rule_list, link) {
 243                 /*
 244                  * Skip this rule if it is only intended for jailed mount points
 245                  * and the current mount point isn't jailed
 246                  */
 247                 if ((rule->rule_type & DEVFS_RULE_JAIL) &&
 248                         (!(DEVFS_MNTDATA(mp)->jailed)) )
 249                         continue;
 250
 251                 /*
 252                  * Skip this rule if it is not intended for jailed mount points
 253                  * and the current mount point is jailed.
 254                  */
 255                 if (!(rule->rule_type & DEVFS_RULE_JAIL) &&
 256                         (DEVFS_MNTDATA(mp)->jailed))
 257                     continue;
 258
 259                 /*
 260                  * Skip this rule if the mount point specified in the rule doesn't
 261                  * match the mount point of the node
 262                  */
 263                 if ((rule->mntpoint[0] != '*') &&
 264                         (strcmp(rule->mntpoint, mp->mnt_stat.f_mntonname)))
 265                         continue;
 266
 267                 /*
 268                  * Skip this rule if this is a by-type rule and the device flags
 269                  * don't match the specified device type in the rule
 270                  */
 271                 if ((rule->rule_type & DEVFS_RULE_TYPE) &&
 272                         ( (rule->dev_type == 0) || (!dev_is_good(node->d_dev)) ||
 273                           (!(dev_dflags(node->d_dev) & rule->dev_type))) )
 274                         continue;
 275
 276                 /*
 277                  * Skip this rule if this is a by-name rule and the node name
 278                  * doesn't match the wildcard string in the rule
 279                  */
 280                 if ((rule->rule_type & DEVFS_RULE_NAME) &&
 281                         (!devfs_rule_checkname(rule, node)) )
 282                         continue;
 283
 284                 if (rule->rule_cmd & DEVFS_RULE_HIDE) {
 285                         /*
 286                          * If we should hide the device, we just apply the relevant
 287                          * hide flag to the node and let devfs do the rest in the
 288                          * vnops
 289                          */
 290                         if ((node->d_dir.d_namlen == 5) &&
 291                                 (!memcmp(node->d_dir.d_name, "devfs", 5))) {
 292                                 /*
 293                                  * Magically avoid /dev/devfs from being hidden, so that one
 294                                  * can still use the rule system even after a "* hide".
 295                                  */
 296                                  continue;
 297                         }
 298                         node->flags |= (DEVFS_HIDDEN | DEVFS_RULE_HIDDEN);
 299                 } else if (rule->rule_cmd & DEVFS_RULE_SHOW) {
 300                         /*
 301                          * Show rule just means that the node should not be hidden, so
 302                          * what we do is clear the hide flag from the node.
 303                          */
 304                         node->flags &= ~DEVFS_HIDDEN;
 305                 } else if (rule->rule_cmd & DEVFS_RULE_LINK) {
 306                         /*
 307                          * This is a LINK rule, so we tell devfs to create
 308                          * a link with the correct name to this node.
 309                          */
 310                         devfs_rule_create_link(node, rule);
 311 #if 0
 312                         devfs_alias_create(rule->linkname, node, 1);
 313 #endif
 314                 } else if (rule->rule_cmd & DEVFS_RULE_PERM) {
 315                         /*
 316                          * This is a normal ownership/permission rule. We
 317                          * just apply the permissions and ownership and
 318                          * we are done.
 319                          */
 320                         node->mode = rule->mode;
 321                         node->uid = rule->uid;
 322                         node->gid = rule->gid;
 323                 }
 324         }
 325
 326         /* If we acquired the lock, we also get rid of it */
 327         if (locked)
 328                 lockmgr(&devfs_rule_lock, LK_RELEASE);
 329
 330         return NULL;
 331 }
 332
 333
 334 static int
 335 devfs_rule_checkname(struct devfs_rule *rule, struct devfs_node *node)
 336 {
 337         struct devfs_node *parent = DEVFS_MNTDATA(node->mp)->root_node;
 338         char *path = NULL;
 339         char *name, name_buf[PATH_MAX];
 340         int no_match = 0;
 341
 342         devfs_resolve_name_path(rule->name, name_buf, &path, &name);
 343         parent = devfs_resolve_or_create_path(parent, path, 0);
 344
 345         if (parent == NULL)
 346                 return 0; /* no match */
 347
 348         /* Check if node is a child of the parent we found */
 349         if (node->parent != parent)
 350                 return 0; /* no match */
 351
 352 #if 0
 353         if (rule->rule_type & DEVFS_RULE_LINK)
 354                 no_match = memcmp(name, node->d_dir.d_name, strlen(name));
 355         else
 356 #endif
 357         no_match = WildCaseCmp(name, node->d_dir.d_name);
 358
 359         return !no_match;
 360 }
 361
 362
 363 static int
 364 devfs_dev_open(struct dev_open_args *ap)
 365 {
 366         /*
 367          * Only allow read-write access.
 368          */
 369         if (((ap->a_oflags & FWRITE) == 0) || ((ap->a_oflags & FREAD) == 0))
 370                 return(EPERM);
 371
 372         /*
 373          * We don't allow nonblocking access.
 374          */
 375         if ((ap->a_oflags & O_NONBLOCK) != 0) {
 376                 devfs_debug(DEVFS_DEBUG_SHOW, "devfs_dev: can't do nonblocking access\n");
 377                 return(ENODEV);
 378         }
 379
 380         return 0;
 381 }
 382
 383
 384 static int
 385 devfs_dev_close(struct dev_close_args *ap)
 386 {
 387         return 0;
 388 }
 389
 390
 391 static int
 392 devfs_dev_ioctl(struct dev_ioctl_args *ap)
 393 {
 394         int error;
 395         struct devfs_rule_ioctl *rule;
 396
 397         error = 0;
 398         rule = (struct devfs_rule_ioctl *)ap->a_data;
 399
 400         switch(ap->a_cmd) {
 401         case DEVFS_RULE_ADD:
 402                 devfs_rule_insert(rule);
 403                 break;
 404
 405         case DEVFS_RULE_APPLY:
 406                 devfs_apply_rules(rule->mntpoint);
 407                 break;
 408
 409         case DEVFS_RULE_CLEAR:
 410                 devfs_rule_clear(rule);
 411                 break;
 412
 413         case DEVFS_RULE_RESET:
 414                 devfs_reset_rules(rule->mntpoint);
 415                 break;
 416
 417         default:
 418                 error = ENOTTY; /* Inappropriate ioctl for device */
 419                 break;
 420         }
 421
 422         return(error);
 423 }
 424
 425
 426 static void
 427 devfs_dev_init(void *unused)
 428 {
 429         lockinit(&devfs_rule_lock, "devfs_rule lock", 0, 0);
 430
 431     devfs_rule_cache = objcache_create("devfs-rule-cache", 0, 0,
 432                         NULL, NULL, NULL,
 433                         objcache_malloc_alloc,
 434                         objcache_malloc_free,
 435                         &devfs_rule_malloc_args );
 436
 437     devfs_dev = make_dev(&devfs_dev_ops,
 438             0,
 439             UID_ROOT,
 440             GID_WHEEL,
 441             0600,
 442             "devfs");
 443 }
 444
 445
 446 static void
 447 devfs_dev_uninit(void *unused)
 448 {
 449         /* XXX: destroy all rules first */
 450     destroy_dev(devfs_dev);
 451         objcache_destroy(devfs_rule_cache);
 452 }
 453
 454
 455 SYSINIT(devfsdev,SI_SUB_DRIVERS,SI_ORDER_FIRST,devfs_dev_init,NULL)
 456 SYSUNINIT(devfsdev, SI_SUB_DRIVERS,SI_ORDER_FIRST,devfs_dev_uninit, NULL);
 457
 458 #if 0
 459
 460 static int
 461 WildCmp(const char *w, const char *s)
 462 {
 463     int i;
 464     int c;
 465     int slen = strlen(s);
 466     const char **mary;
 467
 468     for (i = c = 0; w[i]; ++i) {
 469         if (w[i] == '*')
 470             ++c;
 471     }
 472     mary = kmalloc(sizeof(char *) * (c + 1), M_DEVFS, M_WAITOK);
 473     for (i = 0; i < c; ++i)
 474         mary[i] = s + slen;
 475     i = wildCmp(mary, 0, w, s);
 476     kfree(mary, M_DEVFS);
 477     return(i);
 478 }
 479
 480 #endif
 481
 482 static int
 483 WildCaseCmp(const char *w, const char *s)
 484 {
 485     int i;
 486     int c;
 487     int slen = strlen(s);
 488     const char **mary;
 489
 490     for (i = c = 0; w[i]; ++i) {
 491         if (w[i] == '*')
 492             ++c;
 493     }
 494     mary = kmalloc(sizeof(char *) * (c + 1), M_DEVFS, M_WAITOK);
 495     for (i = 0; i < c; ++i)
 496         mary[i] = s + slen;
 497     i = wildCaseCmp(mary, 0, w, s);
 498     kfree(mary, M_DEVFS);
 499     return(i);
 500 }
 501
 502 /*
 503  * WildCmp() - compare wild string to sane string
 504  *
 505  *      Returns 0 on success, -1 on failure.
 506  */
 507 static int
 508 wildCmp(const char **mary, int d, const char *w, const char *s)
 509 {
 510     int i;
 511
 512     /*
 513      * skip fixed portion
 514      */
 515     for (;;) {
 516         switch(*w) {
 517         case '*':
 518             /*
 519              * optimize terminator
 520              */
 521             if (w[1] == 0)
 522                 return(0);
 523             if (w[1] != '?' && w[1] != '*') {
 524                 /*
 525                  * optimize * followed by non-wild
 526                  */
 527                 for (i = 0; s + i < mary[d]; ++i) {
 528                     if (s[i] == w[1] && wildCmp(mary, d + 1, w + 1, s + i) == 0)
 529                         return(0);
 530                 }
 531             } else {
 532                 /*
 533                  * less-optimal
 534                  */
 535                 for (i = 0; s + i < mary[d]; ++i) {
 536                     if (wildCmp(mary, d + 1, w + 1, s + i) == 0)
 537                         return(0);
 538                 }
 539             }
 540             mary[d] = s;
 541             return(-1);
 542         case '?':
 543             if (*s == 0)
 544                 return(-1);
 545             ++w;
 546             ++s;
 547             break;
 548         default:
 549             if (*w != *s)
 550                 return(-1);
 551             if (*w == 0)        /* terminator */
 552                 return(0);
 553             ++w;
 554             ++s;
 555             break;
 556         }
 557     }
 558     /* not reached */
 559     return(-1);
 560 }
 561
 562
 563 /*
 564  * WildCaseCmp() - compare wild string to sane string, case insensitive
 565  *
 566  *      Returns 0 on success, -1 on failure.
 567  */
 568 static int
 569 wildCaseCmp(const char **mary, int d, const char *w, const char *s)
 570 {
 571     int i;
 572
 573     /*
 574      * skip fixed portion
 575      */
 576     for (;;) {
 577         switch(*w) {
 578         case '*':
 579             /*
 580              * optimize terminator
 581              */
 582             if (w[1] == 0)
 583                 return(0);
 584             if (w[1] != '?' && w[1] != '*') {
 585                 /*
 586                  * optimize * followed by non-wild
 587                  */
 588                 for (i = 0; s + i < mary[d]; ++i) {
 589                     if (s[i] == w[1] && wildCaseCmp(mary, d + 1, w + 1, s + i) == 0)
 590                         return(0);
 591                 }
 592             } else {
 593                 /*
 594                  * less-optimal
 595                  */
 596                 for (i = 0; s + i < mary[d]; ++i) {
 597                     if (wildCaseCmp(mary, d + 1, w + 1, s + i) == 0)
 598                         return(0);
 599                 }
 600             }
 601             mary[d] = s;
 602             return(-1);
 603         case '?':
 604             if (*s == 0)
 605                 return(-1);
 606             ++w;
 607             ++s;
 608             break;
 609         default:
 610             if (*w != *s) {
 611 #define tolower(x)      ((x >= 'A' && x <= 'Z')?(x+('a'-'A')):(x))
 612                 if (tolower(*w) != tolower(*s))
 613                     return(-1);
 614             }
 615             if (*w == 0)        /* terminator */
 616                 return(0);
 617             ++w;
 618             ++s;
 619             break;
 620         }
 621     }
 622     /* not reached */
 623     return(-1);
 624 }