sys/kern/kern_sysctl.c

   1 /*-
   2  * Copyright (c) 1982, 1986, 1989, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Mike Karels at Berkeley Software Design, Inc.
   7  *
   8  * Quite extensively rewritten by Poul-Henning Kamp of the FreeBSD
   9  * project, to make these variables more userfriendly.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in the
  18  *    documentation and/or other materials provided with the distribution.
  19  * 3. All advertising materials mentioning features or use of this software
  20  *    must display the following acknowledgement:
  21  *      This product includes software developed by the University of
  22  *      California, Berkeley and its contributors.
  23  * 4. Neither the name of the University nor the names of its contributors
  24  *    may be used to endorse or promote products derived from this software
  25  *    without specific prior written permission.
  26  *
  27  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  30  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  37  * SUCH DAMAGE.
  38  *
  39  *      @(#)kern_sysctl.c       8.4 (Berkeley) 4/14/94
  40  * $FreeBSD: src/sys/kern/kern_sysctl.c,v 1.92.2.9 2003/05/01 22:48:09 trhodes Exp $
  41  * $DragonFly: src/sys/kern/kern_sysctl.c,v 1.29 2008/01/06 16:55:51 swildner Exp $
  42  */
  43
  44 #include <sys/param.h>
  45 #include <sys/systm.h>
  46 #include <sys/kernel.h>
  47 #include <sys/buf.h>
  48 #include <sys/sysctl.h>
  49 #include <sys/malloc.h>
  50 #include <sys/proc.h>
  51 #include <sys/sysproto.h>
  52 #include <sys/lock.h>
  53 #include <vm/vm.h>
  54 #include <vm/vm_extern.h>
  55
  56 static MALLOC_DEFINE(M_SYSCTL, "sysctl", "sysctl internal magic");
  57 static MALLOC_DEFINE(M_SYSCTLOID, "sysctloid", "sysctl dynamic oids");
  58
  59 static struct lock sysctl_lkp;
  60 static struct lock sysctl_ctx_lkp;
  61
  62 static void     sysctl_lock(int type);
  63 static void     sysctl_unlock(void);
  64 static void     sysctl_ctx_lock(int type);
  65 static void     sysctl_ctx_unlock(void);
  66
  67 static int      sysctl_root(SYSCTL_HANDLER_ARGS);
  68 static void     sysctl_register_oid_int(struct sysctl_oid *oipd);
  69 static void     sysctl_unregister_oid_int(struct sysctl_oid *oipd);
  70 static struct sysctl_ctx_entry* sysctl_ctx_entry_find_int
  71         (struct sysctl_ctx_list *, struct sysctl_oid *oidp);
  72
  73 struct sysctl_oid_list sysctl__children; /* root list */
  74
  75 static struct sysctl_oid *
  76 sysctl_find_oidname(const char *name, struct sysctl_oid_list *list, int lock)
  77 {
  78         struct sysctl_oid *oidp;
  79
  80         SLIST_FOREACH(oidp, list, oid_link) {
  81                 if (strcmp(oidp->oid_name, name) == 0) {
  82                         break;
  83                 }
  84         }
  85         return (oidp);
  86 }
  87
  88 /*
  89  * Initialization of the MIB tree.
  90  *
  91  * Order by number in each list.
  92  */
  93
  94 void
  95 sysctl_register_oid(struct sysctl_oid *oidp)
  96 {
  97         sysctl_lock(LK_EXCLUSIVE);
  98         sysctl_register_oid_int(oidp);
  99         sysctl_unlock();
 100 }
 101
 102 static void
 103 sysctl_register_oid_int(struct sysctl_oid *oidp)
 104 {
 105         struct sysctl_oid_list *parent = oidp->oid_parent;
 106         struct sysctl_oid *p;
 107         struct sysctl_oid *q;
 108
 109         /*
 110          * First check if another oid with the same name already
 111          * exists in the parent's list.
 112          */
 113         p = sysctl_find_oidname(oidp->oid_name, parent, 0);
 114         if (p != NULL) {
 115                 if ((p->oid_kind & CTLTYPE) == CTLTYPE_NODE)
 116                         p->oid_refcnt++;
 117                 else
 118                         kprintf("can't re-use a leaf (%s)!\n", p->oid_name);
 119                 return;
 120         }
 121
 122         /*
 123          * If this oid has a number OID_AUTO, give it a number which
 124          * is greater than any current oid.  Make sure it is at least
 125          * 256 to leave space for pre-assigned oid numbers.
 126          */
 127         if (oidp->oid_number == OID_AUTO) {
 128                 int newoid = 0x100;     /* minimum AUTO oid */
 129
 130                 /*
 131                  * Adjust based on highest oid in parent list
 132                  */
 133                 SLIST_FOREACH(p, parent, oid_link) {
 134                         if (newoid <= p->oid_number)
 135                                 newoid = p->oid_number + 1;
 136                 }
 137                 oidp->oid_number = newoid;
 138         }
 139
 140         /*
 141          * Insert the oid into the parent's list in order.
 142          */
 143         q = NULL;
 144         SLIST_FOREACH(p, parent, oid_link) {
 145                 if (oidp->oid_number < p->oid_number)
 146                         break;
 147                 q = p;
 148         }
 149         if (q)
 150                 SLIST_INSERT_AFTER(q, oidp, oid_link);
 151         else
 152                 SLIST_INSERT_HEAD(parent, oidp, oid_link);
 153 }
 154
 155 void
 156 sysctl_unregister_oid(struct sysctl_oid *oidp)
 157 {
 158         sysctl_lock(LK_EXCLUSIVE);
 159         sysctl_unregister_oid_int(oidp);
 160         sysctl_unlock();
 161 }
 162
 163 static void
 164 sysctl_unregister_oid_int(struct sysctl_oid *oidp)
 165 {
 166         struct sysctl_oid *p;
 167
 168         if (oidp->oid_number == OID_AUTO)
 169                 panic("Trying to unregister OID_AUTO entry: %p", oidp);
 170
 171         SLIST_FOREACH(p, oidp->oid_parent, oid_link) {
 172                 if (p != oidp)
 173                         continue;
 174                 SLIST_REMOVE(oidp->oid_parent, oidp, sysctl_oid, oid_link);
 175                 return;
 176         }
 177
 178         /*
 179          * This can happen when a module fails to register and is
 180          * being unloaded afterwards.  It should not be a panic()
 181          * for normal use.
 182          */
 183         kprintf("%s: failed to unregister sysctl\n", __func__);
 184 }
 185
 186 /* Initialize a new context to keep track of dynamically added sysctls. */
 187 int
 188 sysctl_ctx_init(struct sysctl_ctx_list *c)
 189 {
 190         if (c == NULL)
 191                 return(EINVAL);
 192         TAILQ_INIT(c);
 193         return(0);
 194 }
 195
 196 /* Free the context, and destroy all dynamic oids registered in this context */
 197 int
 198 sysctl_ctx_free(struct sysctl_ctx_list *clist)
 199 {
 200         struct sysctl_ctx_entry *e, *e1;
 201         int error;
 202
 203         error = 0;
 204         sysctl_ctx_lock(LK_EXCLUSIVE);
 205         /*
 206          * First perform a "dry run" to check if it's ok to remove oids.
 207          * XXX FIXME
 208          * XXX This algorithm is a hack. But I don't know any
 209          * XXX better solution for now...
 210          */
 211         TAILQ_FOREACH(e, clist, link) {
 212                 error = sysctl_remove_oid(e->entry, 0, 0);
 213                 if (error)
 214                         break;
 215         }
 216         /*
 217          * Restore deregistered entries, either from the end,
 218          * or from the place where error occured.
 219          * e contains the entry that was not unregistered
 220          */
 221         if (error)
 222                 e1 = TAILQ_PREV(e, sysctl_ctx_list, link);
 223         else
 224                 e1 = TAILQ_LAST(clist, sysctl_ctx_list);
 225         while (e1 != NULL) {
 226                 sysctl_register_oid(e1->entry);
 227                 e1 = TAILQ_PREV(e1, sysctl_ctx_list, link);
 228         }
 229         if (error) {
 230                 sysctl_ctx_unlock();
 231                 return(EBUSY);
 232         }
 233         /* Now really delete the entries */
 234         e = TAILQ_FIRST(clist);
 235         while (e != NULL) {
 236                 e1 = TAILQ_NEXT(e, link);
 237                 error = sysctl_remove_oid(e->entry, 1, 0);
 238                 if (error)
 239                         panic("sysctl_remove_oid: corrupt tree, entry: %s",
 240                             e->entry->oid_name);
 241                 kfree(e, M_SYSCTLOID);
 242                 e = e1;
 243         }
 244         sysctl_ctx_unlock();
 245         return (error);
 246 }
 247
 248 /* Add an entry to the context */
 249 struct sysctl_ctx_entry *
 250 sysctl_ctx_entry_add(struct sysctl_ctx_list *clist, struct sysctl_oid *oidp)
 251 {
 252         struct sysctl_ctx_entry *e;
 253
 254         if (clist == NULL || oidp == NULL)
 255                 return(NULL);
 256         e = kmalloc(sizeof(struct sysctl_ctx_entry), M_SYSCTLOID, M_WAITOK);
 257         e->entry = oidp;
 258         sysctl_ctx_lock(LK_EXCLUSIVE);
 259         TAILQ_INSERT_HEAD(clist, e, link);
 260         sysctl_ctx_unlock();
 261         return (e);
 262 }
 263
 264 /* Find an entry in the context */
 265 struct sysctl_ctx_entry *
 266 sysctl_ctx_entry_find(struct sysctl_ctx_list *clist, struct sysctl_oid *oidp)
 267 {
 268         struct sysctl_ctx_entry *e;
 269
 270         if (clist == NULL || oidp == NULL)
 271                 return(NULL);
 272
 273         sysctl_ctx_lock(LK_SHARED);
 274         e = sysctl_ctx_entry_find_int(clist, oidp);
 275         sysctl_ctx_unlock();
 276
 277         return(e);
 278 }
 279
 280 struct sysctl_ctx_entry *
 281 sysctl_ctx_entry_find_int(struct sysctl_ctx_list *clist, struct sysctl_oid *oidp)
 282 {
 283         struct sysctl_ctx_entry *e;
 284
 285         KKASSERT(clist != NULL && oidp != NULL);
 286
 287         for (e = TAILQ_FIRST(clist); e != NULL; e = TAILQ_NEXT(e, link)) {
 288                 if(e->entry == oidp)
 289                         break;
 290         }
 291
 292         return (e);
 293 }
 294
 295 /*
 296  * Delete an entry from the context.
 297  * NOTE: this function doesn't free oidp! You have to remove it
 298  * with sysctl_remove_oid().
 299  */
 300 int
 301 sysctl_ctx_entry_del(struct sysctl_ctx_list *clist, struct sysctl_oid *oidp)
 302 {
 303         struct sysctl_ctx_entry *e;
 304
 305         if (clist == NULL || oidp == NULL)
 306                 return (EINVAL);
 307
 308         sysctl_ctx_lock(LK_EXCLUSIVE);
 309         e = sysctl_ctx_entry_find_int(clist, oidp);
 310         if (e == NULL) {
 311                 sysctl_ctx_unlock();
 312                 return (ENOENT);
 313         }
 314         TAILQ_REMOVE(clist, e, link);
 315         kfree(e, M_SYSCTLOID);
 316         sysctl_ctx_unlock();
 317
 318         return(0);
 319 }
 320
 321 /*
 322  * Remove dynamically created sysctl trees.
 323  * oidp - top of the tree to be removed
 324  * del - if 0 - just deregister, otherwise free up entries as well
 325  * recurse - if != 0 traverse the subtree to be deleted
 326  */
 327 int
 328 sysctl_remove_oid(struct sysctl_oid *oidp, int del, int recurse)
 329 {
 330         struct sysctl_oid *p;
 331         int error;
 332
 333         if (oidp == NULL)
 334                 return(EINVAL);
 335         if ((oidp->oid_kind & CTLFLAG_DYN) == 0) {
 336                 kprintf("can't remove non-dynamic nodes!\n");
 337                 return (EINVAL);
 338         }
 339         sysctl_lock(LK_EXCLUSIVE | LK_CANRECURSE);
 340         /*
 341          * WARNING: normal method to do this should be through
 342          * sysctl_ctx_free(). Use recursing as the last resort
 343          * method to purge your sysctl tree of leftovers...
 344          * However, if some other code still references these nodes,
 345          * it will panic.
 346          */
 347         if ((oidp->oid_kind & CTLTYPE) == CTLTYPE_NODE) {
 348                 if (oidp->oid_refcnt == 1) {
 349                         SLIST_FOREACH(p, SYSCTL_CHILDREN(oidp), oid_link) {
 350                                 if (!recurse) {
 351                                         sysctl_unlock();
 352                                         return(ENOTEMPTY);
 353                                 }
 354                                 error = sysctl_remove_oid(p, del, recurse);
 355                                 if (error) {
 356                                         sysctl_unlock();
 357                                         return(error);
 358                                 }
 359                         }
 360                         if (del)
 361                                 kfree(SYSCTL_CHILDREN(oidp), M_SYSCTLOID);
 362                 }
 363         }
 364         if (oidp->oid_refcnt > 1 ) {
 365                 oidp->oid_refcnt--;
 366         } else {
 367                 if (oidp->oid_refcnt == 0) {
 368                         kprintf("Warning: bad oid_refcnt=%u (%s)!\n",
 369                                oidp->oid_refcnt, oidp->oid_name);
 370                         sysctl_unlock();
 371                         return(EINVAL);
 372                 }
 373                 sysctl_unregister_oid_int(oidp);
 374                 if (del) {
 375                         if (oidp->oid_descr)
 376                                 kfree(__DECONST(char *,oidp->oid_descr),
 377                                      M_SYSCTLOID);
 378                         kfree(__DECONST(char *, oidp->oid_name), M_SYSCTLOID);
 379                         kfree(oidp, M_SYSCTLOID);
 380                 }
 381         }
 382         sysctl_unlock();
 383         return(0);
 384 }
 385
 386 /*
 387  * Create new sysctls at run time.
 388  * clist may point to a valid context initialized with sysctl_ctx_init().
 389  */
 390 struct sysctl_oid *
 391 sysctl_add_oid(struct sysctl_ctx_list *clist, struct sysctl_oid_list *parent,
 392         int number, const char *name, int kind, void *arg1, int arg2,
 393         int (*handler)(SYSCTL_HANDLER_ARGS), const char *fmt, const char *descr)
 394 {
 395         struct sysctl_oid *oidp;
 396         ssize_t len;
 397         char *newname;
 398
 399         /* You have to hook up somewhere.. */
 400         if (parent == NULL)
 401                 return(NULL);
 402         sysctl_lock(LK_EXCLUSIVE);
 403         /* Check if the node already exists, otherwise create it */
 404         oidp = sysctl_find_oidname(name, parent, 0);
 405         if (oidp != NULL) {
 406                 if ((oidp->oid_kind & CTLTYPE) == CTLTYPE_NODE) {
 407                         oidp->oid_refcnt++;
 408                         /* Update the context */
 409                         if (clist != NULL)
 410                                 sysctl_ctx_entry_add(clist, oidp);
 411                         sysctl_unlock();
 412                         return (oidp);
 413                 } else {
 414                         kprintf("can't re-use a leaf (%s)!\n", name);
 415                         sysctl_unlock();
 416                         return (NULL);
 417                 }
 418         }
 419         oidp = kmalloc(sizeof(struct sysctl_oid), M_SYSCTLOID, M_WAITOK | M_ZERO);
 420         oidp->oid_parent = parent;
 421         SLIST_NEXT(oidp, oid_link) = NULL;
 422         oidp->oid_number = number;
 423         oidp->oid_refcnt = 1;
 424         len = strlen(name);
 425         newname = kmalloc(len + 1, M_SYSCTLOID, M_WAITOK);
 426         bcopy(name, newname, len + 1);
 427         newname[len] = '\0';
 428         oidp->oid_name = newname;
 429         oidp->oid_handler = handler;
 430         oidp->oid_kind = CTLFLAG_DYN | kind;
 431         if ((kind & CTLTYPE) == CTLTYPE_NODE) {
 432                 struct sysctl_oid_list *children;
 433
 434                 /* Allocate space for children */
 435                 children = kmalloc(sizeof(*children), M_SYSCTLOID, M_WAITOK);
 436                 SYSCTL_SET_CHILDREN(oidp, children);
 437                 SLIST_INIT(children);
 438         } else {
 439                 oidp->oid_arg1 = arg1;
 440                 oidp->oid_arg2 = arg2;
 441         }
 442         oidp->oid_fmt = fmt;
 443         if (descr) {
 444                 int len = strlen(descr) + 1;
 445                 oidp->oid_descr = kmalloc(len, M_SYSCTLOID, M_WAITOK);
 446                 strcpy((char *)(uintptr_t)(const void *)oidp->oid_descr, descr);
 447         };
 448         /* Update the context, if used */
 449         if (clist != NULL)
 450                 sysctl_ctx_entry_add(clist, oidp);
 451         /* Register this oid */
 452         sysctl_register_oid_int(oidp);
 453         sysctl_unlock();
 454         return (oidp);
 455 }
 456
 457 /*
 458  * Register the kernel's oids on startup.
 459  */
 460 SET_DECLARE(sysctl_set, struct sysctl_oid);
 461
 462 static void
 463 sysctl_register_all(void *arg)
 464 {
 465         struct sysctl_oid **oidp;
 466
 467         lockinit(&sysctl_lkp, "sysctl", 0, 0);
 468         lockinit(&sysctl_ctx_lkp, "sysctl ctx", 0, 0);
 469         SET_FOREACH(oidp, sysctl_set)
 470                 sysctl_register_oid_int(*oidp);
 471 }
 472
 473 SYSINIT(sysctl, SI_BOOT1_POST, SI_ORDER_ANY, sysctl_register_all, 0);
 474
 475 /*
 476  * "Staff-functions"
 477  *
 478  * These functions implement a presently undocumented interface
 479  * used by the sysctl program to walk the tree, and get the type
 480  * so it can print the value.
 481  * This interface is under work and consideration, and should probably
 482  * be killed with a big axe by the first person who can find the time.
 483  * (be aware though, that the proper interface isn't as obvious as it
 484  * may seem, there are various conflicting requirements.
 485  *
 486  * {0,0}        kprintf the entire MIB-tree.
 487  * {0,1,...}    return the name of the "..." OID.
 488  * {0,2,...}    return the next OID.
 489  * {0,3}        return the OID of the name in "new"
 490  * {0,4,...}    return the kind & format info for the "..." OID.
 491  */
 492
 493 static void
 494 sysctl_sysctl_debug_dump_node(struct sysctl_oid_list *l, int i)
 495 {
 496         int k;
 497         struct sysctl_oid *oidp;
 498
 499         sysctl_lock(LK_SHARED);
 500         SLIST_FOREACH(oidp, l, oid_link) {
 501
 502                 for (k=0; k<i; k++)
 503                         kprintf(" ");
 504
 505                 kprintf("%d %s ", oidp->oid_number, oidp->oid_name);
 506
 507                 kprintf("%c%c",
 508                         oidp->oid_kind & CTLFLAG_RD ? 'R':' ',
 509                         oidp->oid_kind & CTLFLAG_WR ? 'W':' ');
 510
 511                 if (oidp->oid_handler)
 512                         kprintf(" *Handler");
 513
 514                 switch (oidp->oid_kind & CTLTYPE) {
 515                         case CTLTYPE_NODE:
 516                                 kprintf(" Node\n");
 517                                 if (!oidp->oid_handler) {
 518                                         sysctl_sysctl_debug_dump_node(
 519                                                 oidp->oid_arg1, i+2);
 520                                 }
 521                                 break;
 522                         case CTLTYPE_INT:    kprintf(" Int\n"); break;
 523                         case CTLTYPE_STRING: kprintf(" String\n"); break;
 524                         case CTLTYPE_QUAD:   kprintf(" Quad\n"); break;
 525                         case CTLTYPE_OPAQUE: kprintf(" Opaque/struct\n"); break;
 526                         default:             kprintf("\n");
 527                 }
 528
 529         }
 530         sysctl_unlock();
 531 }
 532
 533 static int
 534 sysctl_sysctl_debug(SYSCTL_HANDLER_ARGS)
 535 {
 536         int error;
 537
 538         error = suser(req->td);
 539         if (error)
 540                 return error;
 541         sysctl_sysctl_debug_dump_node(&sysctl__children, 0);
 542         return ENOENT;
 543 }
 544
 545 SYSCTL_PROC(_sysctl, 0, debug, CTLTYPE_STRING|CTLFLAG_RD,
 546         0, 0, sysctl_sysctl_debug, "-", "");
 547
 548 static int
 549 sysctl_sysctl_name(SYSCTL_HANDLER_ARGS)
 550 {
 551         int *name = (int *) arg1;
 552         u_int namelen = arg2;
 553         int error = 0;
 554         struct sysctl_oid *oid;
 555         struct sysctl_oid_list *lsp = &sysctl__children, *lsp2;
 556         char buf[10];
 557
 558         sysctl_lock(LK_SHARED);
 559         while (namelen) {
 560                 if (!lsp) {
 561                         ksnprintf(buf,sizeof(buf),"%d",*name);
 562                         if (req->oldidx)
 563                                 error = SYSCTL_OUT(req, ".", 1);
 564                         if (!error)
 565                                 error = SYSCTL_OUT(req, buf, strlen(buf));
 566                         if (error) {
 567                                 sysctl_unlock();
 568                                 return (error);
 569                         }
 570                         namelen--;
 571                         name++;
 572                         continue;
 573                 }
 574                 lsp2 = 0;
 575                 SLIST_FOREACH(oid, lsp, oid_link) {
 576                         if (oid->oid_number != *name)
 577                                 continue;
 578
 579                         if (req->oldidx)
 580                                 error = SYSCTL_OUT(req, ".", 1);
 581                         if (!error)
 582                                 error = SYSCTL_OUT(req, oid->oid_name,
 583                                         strlen(oid->oid_name));
 584                         if (error) {
 585                                 sysctl_unlock();
 586                                 return (error);
 587                         }
 588
 589                         namelen--;
 590                         name++;
 591
 592                         if ((oid->oid_kind & CTLTYPE) != CTLTYPE_NODE)
 593                                 break;
 594
 595                         if (oid->oid_handler)
 596                                 break;
 597
 598                         lsp2 = (struct sysctl_oid_list *)oid->oid_arg1;
 599                         break;
 600                 }
 601                 lsp = lsp2;
 602         }
 603         sysctl_unlock();
 604         return (SYSCTL_OUT(req, "", 1));
 605 }
 606
 607 SYSCTL_NODE(_sysctl, 1, name, CTLFLAG_RD, sysctl_sysctl_name, "");
 608
 609 static int
 610 sysctl_sysctl_next_ls(struct sysctl_oid_list *lsp, int *name, u_int namelen,
 611         int *next, int *len, int level, struct sysctl_oid **oidpp)
 612 {
 613         struct sysctl_oid *oidp;
 614
 615         *len = level;
 616         sysctl_lock(LK_SHARED);
 617         SLIST_FOREACH(oidp, lsp, oid_link) {
 618                 *next = oidp->oid_number;
 619                 *oidpp = oidp;
 620
 621                 if (!namelen) {
 622                         if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE) {
 623                                 sysctl_unlock();
 624                                 return 0;
 625                         }
 626                         if (oidp->oid_handler) {
 627                                 /* We really should call the handler here...*/
 628                                 sysctl_unlock();
 629                                 return 0;
 630                         }
 631                         lsp = (struct sysctl_oid_list *)oidp->oid_arg1;
 632                         if (!sysctl_sysctl_next_ls(lsp, 0, 0, next+1,
 633                                 len, level+1, oidpp)) {
 634                                 sysctl_unlock();
 635                                 return 0;
 636                         }
 637                         goto emptynode;
 638                 }
 639
 640                 if (oidp->oid_number < *name)
 641                         continue;
 642
 643                 if (oidp->oid_number > *name) {
 644                         if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE) {
 645                                 sysctl_unlock();
 646                                 return 0;
 647                         }
 648                         if (oidp->oid_handler) {
 649                                 sysctl_unlock();
 650                                 return 0;
 651                         }
 652                         lsp = (struct sysctl_oid_list *)oidp->oid_arg1;
 653                         if (!sysctl_sysctl_next_ls(lsp, name+1, namelen-1,
 654                                 next+1, len, level+1, oidpp)) {
 655                                 sysctl_unlock();
 656                                 return (0);
 657                         }
 658                         goto next;
 659                 }
 660                 if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE)
 661                         continue;
 662
 663                 if (oidp->oid_handler)
 664                         continue;
 665
 666                 lsp = (struct sysctl_oid_list *)oidp->oid_arg1;
 667                 if (!sysctl_sysctl_next_ls(lsp, name+1, namelen-1, next+1,
 668                         len, level+1, oidpp)) {
 669                         sysctl_unlock();
 670                         return (0);
 671                 }
 672         next:
 673                 namelen = 1;
 674                 *len = level;
 675         emptynode:
 676                 *len = level;
 677         }
 678         sysctl_unlock();
 679         return 1;
 680 }
 681
 682 static int
 683 sysctl_sysctl_next(SYSCTL_HANDLER_ARGS)
 684 {
 685         int *name = (int *) arg1;
 686         u_int namelen = arg2;
 687         int i, j, error;
 688         struct sysctl_oid *oid;
 689         struct sysctl_oid_list *lsp = &sysctl__children;
 690         int newoid[CTL_MAXNAME];
 691
 692         i = sysctl_sysctl_next_ls(lsp, name, namelen, newoid, &j, 1, &oid);
 693         if (i)
 694                 return ENOENT;
 695         error = SYSCTL_OUT(req, newoid, j * sizeof (int));
 696         return (error);
 697 }
 698
 699 SYSCTL_NODE(_sysctl, 2, next, CTLFLAG_RD, sysctl_sysctl_next, "");
 700
 701 static int
 702 name2oid (char *name, int *oid, int *len, struct sysctl_oid **oidpp)
 703 {
 704         int i;
 705         struct sysctl_oid *oidp;
 706         struct sysctl_oid_list *lsp = &sysctl__children;
 707         char *p;
 708
 709         if (!*name)
 710                 return ENOENT;
 711
 712         p = name + strlen(name) - 1 ;
 713         if (*p == '.')
 714                 *p = '\0';
 715
 716         *len = 0;
 717
 718         for (p = name; *p && *p != '.'; p++)
 719                 ;
 720         i = *p;
 721         if (i == '.')
 722                 *p = '\0';
 723
 724         sysctl_lock(LK_SHARED);
 725         oidp = SLIST_FIRST(lsp);
 726
 727         while (oidp && *len < CTL_MAXNAME) {
 728                 if (strcmp(name, oidp->oid_name)) {
 729                         oidp = SLIST_NEXT(oidp, oid_link);
 730                         continue;
 731                 }
 732                 *oid++ = oidp->oid_number;
 733                 (*len)++;
 734
 735                 if (!i) {
 736                         if (oidpp)
 737                                 *oidpp = oidp;
 738                         sysctl_unlock();
 739                         return (0);
 740                 }
 741
 742                 if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE)
 743                         break;
 744
 745                 if (oidp->oid_handler)
 746                         break;
 747
 748                 lsp = (struct sysctl_oid_list *)oidp->oid_arg1;
 749                 oidp = SLIST_FIRST(lsp);
 750                 name = p+1;
 751                 for (p = name; *p && *p != '.'; p++)
 752                                 ;
 753                 i = *p;
 754                 if (i == '.')
 755                         *p = '\0';
 756         }
 757         sysctl_unlock();
 758         return ENOENT;
 759 }
 760
 761 static int
 762 sysctl_sysctl_name2oid(SYSCTL_HANDLER_ARGS)
 763 {
 764         char *p;
 765         int error, oid[CTL_MAXNAME], len;
 766         struct sysctl_oid *op = 0;
 767
 768         if (!req->newlen)
 769                 return ENOENT;
 770         if (req->newlen >= MAXPATHLEN)  /* XXX arbitrary, undocumented */
 771                 return (ENAMETOOLONG);
 772
 773         p = kmalloc(req->newlen+1, M_SYSCTL, M_WAITOK);
 774
 775         error = SYSCTL_IN(req, p, req->newlen);
 776         if (error) {
 777                 kfree(p, M_SYSCTL);
 778                 return (error);
 779         }
 780
 781         p [req->newlen] = '\0';
 782
 783         error = name2oid(p, oid, &len, &op);
 784
 785         kfree(p, M_SYSCTL);
 786
 787         if (error)
 788                 return (error);
 789
 790         error = SYSCTL_OUT(req, oid, len * sizeof *oid);
 791         return (error);
 792 }
 793
 794 SYSCTL_PROC(_sysctl, 3, name2oid, CTLFLAG_RW|CTLFLAG_ANYBODY, 0, 0,
 795         sysctl_sysctl_name2oid, "I", "");
 796
 797 static int
 798 sysctl_sysctl_oidfmt(SYSCTL_HANDLER_ARGS)
 799 {
 800         struct sysctl_oid *oid;
 801         int error;
 802
 803         error = sysctl_find_oid(arg1, arg2, &oid, NULL, req);
 804         if (error)
 805                 return (error);
 806
 807         if (!oid->oid_fmt)
 808                 return (ENOENT);
 809         error = SYSCTL_OUT(req, &oid->oid_kind, sizeof(oid->oid_kind));
 810         if (error)
 811                 return (error);
 812         error = SYSCTL_OUT(req, oid->oid_fmt, strlen(oid->oid_fmt) + 1);
 813         return (error);
 814 }
 815
 816
 817 SYSCTL_NODE(_sysctl, 4, oidfmt, CTLFLAG_RD, sysctl_sysctl_oidfmt, "");
 818
 819 static int
 820 sysctl_sysctl_oiddescr(SYSCTL_HANDLER_ARGS)
 821 {
 822         struct sysctl_oid *oid;
 823         int error;
 824
 825         error = sysctl_find_oid(arg1, arg2, &oid, NULL, req);
 826         if (error)
 827                 return (error);
 828
 829         if (!oid->oid_descr)
 830                 return (ENOENT);
 831         error = SYSCTL_OUT(req, oid->oid_descr, strlen(oid->oid_descr) + 1);
 832         return (error);
 833 }
 834
 835 SYSCTL_NODE(_sysctl, 5, oiddescr, CTLFLAG_RD, sysctl_sysctl_oiddescr, "");
 836
 837 /*
 838  * Default "handler" functions.
 839  */
 840
 841 /*
 842  * Handle an int, signed or unsigned.
 843  * Two cases:
 844  *     a variable:  point arg1 at it.
 845  *     a constant:  pass it in arg2.
 846  */
 847
 848 int
 849 sysctl_handle_int(SYSCTL_HANDLER_ARGS)
 850 {
 851         int error = 0;
 852
 853         if (arg1)
 854                 error = SYSCTL_OUT(req, arg1, sizeof(int));
 855         else
 856                 error = SYSCTL_OUT(req, &arg2, sizeof(int));
 857
 858         if (error || !req->newptr)
 859                 return (error);
 860
 861         if (!arg1)
 862                 error = EPERM;
 863         else
 864                 error = SYSCTL_IN(req, arg1, sizeof(int));
 865         return (error);
 866 }
 867
 868 /*
 869  * Handle a long, signed or unsigned.  arg1 points to it.
 870  */
 871
 872 int
 873 sysctl_handle_long(SYSCTL_HANDLER_ARGS)
 874 {
 875         int error = 0;
 876
 877         if (!arg1)
 878                 return (EINVAL);
 879         error = SYSCTL_OUT(req, arg1, sizeof(long));
 880
 881         if (error || !req->newptr)
 882                 return (error);
 883
 884         error = SYSCTL_IN(req, arg1, sizeof(long));
 885         return (error);
 886 }
 887
 888 /*
 889  * Handle a quad, signed or unsigned.  arg1 points to it.
 890  */
 891
 892 int
 893 sysctl_handle_quad(SYSCTL_HANDLER_ARGS)
 894 {
 895         int error = 0;
 896
 897         if (!arg1)
 898                 return (EINVAL);
 899         error = SYSCTL_OUT(req, arg1, sizeof(quad_t));
 900
 901         if (error || !req->newptr)
 902                 return (error);
 903
 904         error = SYSCTL_IN(req, arg1, sizeof(quad_t));
 905         return (error);
 906 }
 907
 908 /*
 909  * Handle our generic '\0' terminated 'C' string.
 910  * Two cases:
 911  *      a variable string:  point arg1 at it, arg2 is max length.
 912  *      a constant string:  point arg1 at it, arg2 is zero.
 913  */
 914
 915 int
 916 sysctl_handle_string(SYSCTL_HANDLER_ARGS)
 917 {
 918         int error=0;
 919
 920         error = SYSCTL_OUT(req, arg1, strlen((char *)arg1)+1);
 921
 922         if (error || !req->newptr)
 923                 return (error);
 924
 925         if ((req->newlen - req->newidx) >= arg2) {
 926                 error = EINVAL;
 927         } else {
 928                 arg2 = (req->newlen - req->newidx);
 929                 error = SYSCTL_IN(req, arg1, arg2);
 930                 ((char *)arg1)[arg2] = '\0';
 931         }
 932
 933         return (error);
 934 }
 935
 936 /*
 937  * Handle any kind of opaque data.
 938  * arg1 points to it, arg2 is the size.
 939  */
 940
 941 int
 942 sysctl_handle_opaque(SYSCTL_HANDLER_ARGS)
 943 {
 944         int error;
 945
 946         error = SYSCTL_OUT(req, arg1, arg2);
 947
 948         if (error || !req->newptr)
 949                 return (error);
 950
 951         error = SYSCTL_IN(req, arg1, arg2);
 952
 953         return (error);
 954 }
 955
 956 /*
 957  * Transfer functions to/from kernel space.
 958  * XXX: rather untested at this point
 959  */
 960 static int
 961 sysctl_old_kernel(struct sysctl_req *req, const void *p, size_t l)
 962 {
 963         size_t i = 0;
 964
 965         if (req->oldptr) {
 966                 i = l;
 967                 if (i > req->oldlen - req->oldidx)
 968                         i = req->oldlen - req->oldidx;
 969                 if (i > 0)
 970                         bcopy(p, (char *)req->oldptr + req->oldidx, i);
 971         }
 972         req->oldidx += l;
 973         if (req->oldptr && i != l)
 974                 return (ENOMEM);
 975         return (0);
 976 }
 977
 978 static int
 979 sysctl_new_kernel(struct sysctl_req *req, void *p, size_t l)
 980 {
 981
 982         if (!req->newptr)
 983                 return 0;
 984         if (req->newlen - req->newidx < l)
 985                 return (EINVAL);
 986         bcopy((char *)req->newptr + req->newidx, p, l);
 987         req->newidx += l;
 988         return (0);
 989 }
 990
 991 int
 992 kernel_sysctl(int *name, u_int namelen, void *old, size_t *oldlenp, void *new, size_t newlen, size_t *retval)
 993 {
 994         int error = 0;
 995         struct sysctl_req req;
 996
 997         bzero(&req, sizeof req);
 998
 999         req.td = curthread;
1000
1001         if (oldlenp) {
1002                 req.oldlen = *oldlenp;
1003         }
1004
1005         if (old) {
1006                 req.oldptr = old;
1007         }
1008
1009         if (new != NULL) {
1010                 req.newlen = newlen;
1011                 req.newptr = new;
1012         }
1013
1014         req.oldfunc = sysctl_old_kernel;
1015         req.newfunc = sysctl_new_kernel;
1016         req.lock = 1;
1017
1018         sysctl_lock(LK_SHARED);
1019
1020         error = sysctl_root(0, name, namelen, &req);
1021
1022         if (req.lock == 2)
1023                 vsunlock(req.oldptr, req.oldlen);
1024
1025         sysctl_unlock();
1026
1027         if (error && error != ENOMEM)
1028                 return (error);
1029
1030         if (retval) {
1031                 if (req.oldptr && req.oldidx > req.oldlen)
1032                         *retval = req.oldlen;
1033                 else
1034                         *retval = req.oldidx;
1035         }
1036         return (error);
1037 }
1038
1039 int
1040 kernel_sysctlbyname(char *name, void *old, size_t *oldlenp,
1041     void *new, size_t newlen, size_t *retval)
1042 {
1043         int oid[CTL_MAXNAME];
1044         size_t oidlen, plen;
1045         int error;
1046
1047         oid[0] = 0;             /* sysctl internal magic */
1048         oid[1] = 3;             /* name2oid */
1049         oidlen = sizeof(oid);
1050
1051         error = kernel_sysctl(oid, 2, oid, &oidlen, (void *)name,
1052                     strlen(name), &plen);
1053         if (error)
1054                 return (error);
1055
1056         error = kernel_sysctl(oid, plen / sizeof(int), old, oldlenp,
1057             new, newlen, retval);
1058         return (error);
1059 }
1060
1061 /*
1062  * Transfer function to/from user space.
1063  */
1064 static int
1065 sysctl_old_user(struct sysctl_req *req, const void *p, size_t l)
1066 {
1067         int error = 0;
1068         size_t i = 0;
1069
1070         if (req->lock == 1 && req->oldptr) {
1071                 vslock(req->oldptr, req->oldlen);
1072                 req->lock = 2;
1073         }
1074         if (req->oldptr) {
1075                 i = l;
1076                 if (i > req->oldlen - req->oldidx)
1077                         i = req->oldlen - req->oldidx;
1078                 if (i > 0)
1079                         error = copyout(p, (char *)req->oldptr + req->oldidx,
1080                                         i);
1081         }
1082         req->oldidx += l;
1083         if (error)
1084                 return (error);
1085         if (req->oldptr && i < l)
1086                 return (ENOMEM);
1087         return (0);
1088 }
1089
1090 static int
1091 sysctl_new_user(struct sysctl_req *req, void *p, size_t l)
1092 {
1093         int error;
1094
1095         if (!req->newptr)
1096                 return 0;
1097         if (req->newlen - req->newidx < l)
1098                 return (EINVAL);
1099         error = copyin((char *)req->newptr + req->newidx, p, l);
1100         req->newidx += l;
1101         return (error);
1102 }
1103
1104 int
1105 sysctl_find_oid(int *name, u_int namelen, struct sysctl_oid **noid,
1106     int *nindx, struct sysctl_req *req)
1107 {
1108         struct sysctl_oid *oid;
1109         int indx;
1110
1111         sysctl_lock(LK_SHARED);
1112         oid = SLIST_FIRST(&sysctl__children);
1113         indx = 0;
1114         while (oid && indx < CTL_MAXNAME) {
1115                 if (oid->oid_number == name[indx]) {
1116                         indx++;
1117                         if (oid->oid_kind & CTLFLAG_NOLOCK)
1118                                 req->lock = 0;
1119                         if ((oid->oid_kind & CTLTYPE) == CTLTYPE_NODE) {
1120                                 if (oid->oid_handler != NULL ||
1121                                     indx == namelen) {
1122                                         *noid = oid;
1123                                         if (nindx != NULL)
1124                                                 *nindx = indx;
1125                                         sysctl_unlock();
1126                                         return (0);
1127                                 }
1128                                 oid = SLIST_FIRST(
1129                                     (struct sysctl_oid_list *)oid->oid_arg1);
1130                         } else if (indx == namelen) {
1131                                 *noid = oid;
1132                                 if (nindx != NULL)
1133                                         *nindx = indx;
1134                                 sysctl_unlock();
1135                                 return (0);
1136                         } else {
1137                                 sysctl_unlock();
1138                                 return (ENOTDIR);
1139                         }
1140                 } else {
1141                         oid = SLIST_NEXT(oid, oid_link);
1142                 }
1143         }
1144         sysctl_unlock();
1145         return (ENOENT);
1146 }
1147
1148 /*
1149  * Traverse our tree, and find the right node, execute whatever it points
1150  * to, and return the resulting error code.
1151  */
1152
1153 int
1154 sysctl_root(SYSCTL_HANDLER_ARGS)
1155 {
1156         struct thread *td = req->td;
1157         struct proc *p = td ? td->td_proc : NULL;
1158         struct sysctl_oid *oid;
1159         int error, indx;
1160
1161         error = sysctl_find_oid(arg1, arg2, &oid, &indx, req);
1162         if (error)
1163                 return (error);
1164
1165         if ((oid->oid_kind & CTLTYPE) == CTLTYPE_NODE) {
1166                 /*
1167                  * You can't call a sysctl when it's a node, but has
1168                  * no handler.  Inform the user that it's a node.
1169                  * The indx may or may not be the same as namelen.
1170                  */
1171                 if (oid->oid_handler == NULL)
1172                         return (EISDIR);
1173         }
1174
1175         /* If writing isn't allowed */
1176         if (req->newptr && (!(oid->oid_kind & CTLFLAG_WR) ||
1177             ((oid->oid_kind & CTLFLAG_SECURE) && securelevel > 0)))
1178                 return (EPERM);
1179
1180         /* Most likely only root can write */
1181         if (!(oid->oid_kind & CTLFLAG_ANYBODY) && req->newptr && p &&
1182             (error = suser_cred(p->p_ucred,
1183              (oid->oid_kind & CTLFLAG_PRISON) ? PRISON_ROOT : 0)))
1184                 return (error);
1185
1186         if (!oid->oid_handler)
1187                 return EINVAL;
1188
1189         if ((oid->oid_kind & CTLTYPE) == CTLTYPE_NODE)
1190                 error = oid->oid_handler(oid, (int *)arg1 + indx, arg2 - indx,
1191                     req);
1192         else
1193                 error = oid->oid_handler(oid, oid->oid_arg1, oid->oid_arg2,
1194                     req);
1195         return (error);
1196 }
1197
1198 int
1199 sys___sysctl(struct sysctl_args *uap)
1200 {
1201         int error, i, name[CTL_MAXNAME];
1202         size_t j;
1203
1204         if (uap->namelen > CTL_MAXNAME || uap->namelen < 2)
1205                 return (EINVAL);
1206
1207         error = copyin(uap->name, &name, uap->namelen * sizeof(int));
1208         if (error)
1209                 return (error);
1210
1211         error = userland_sysctl(name, uap->namelen,
1212                 uap->old, uap->oldlenp, 0,
1213                 uap->new, uap->newlen, &j);
1214         if (error && error != ENOMEM)
1215                 return (error);
1216         if (uap->oldlenp) {
1217                 i = copyout(&j, uap->oldlenp, sizeof(j));
1218                 if (i)
1219                         return (i);
1220         }
1221         return (error);
1222 }
1223
1224 /*
1225  * This is used from various compatibility syscalls too.  That's why name
1226  * must be in kernel space.
1227  */
1228 int
1229 userland_sysctl(int *name, u_int namelen, void *old, size_t *oldlenp, int inkernel, void *new, size_t newlen, size_t *retval)
1230 {
1231         int error = 0;
1232         struct sysctl_req req, req2;
1233
1234         bzero(&req, sizeof req);
1235
1236         if (oldlenp) {
1237                 if (inkernel) {
1238                         req.oldlen = *oldlenp;
1239                 } else {
1240                         error = copyin(oldlenp, &req.oldlen, sizeof(*oldlenp));
1241                         if (error)
1242                                 return (error);
1243                 }
1244         }
1245
1246         if (old) {
1247                 if (!useracc(old, req.oldlen, VM_PROT_WRITE))
1248                         return (EFAULT);
1249                 req.oldptr= old;
1250         }
1251
1252         if (new != NULL) {
1253                 if (!useracc(new, newlen, VM_PROT_READ))
1254                         return (EFAULT);
1255                 req.newlen = newlen;
1256                 req.newptr = new;
1257         }
1258
1259         req.oldfunc = sysctl_old_user;
1260         req.newfunc = sysctl_new_user;
1261         req.lock = 1;
1262         req.td = curthread;
1263
1264         sysctl_lock(LK_SHARED);
1265
1266         do {
1267             req2 = req;
1268             error = sysctl_root(0, name, namelen, &req2);
1269         } while (error == EAGAIN);
1270
1271         req = req2;
1272         if (req.lock == 2)
1273                 vsunlock(req.oldptr, req.oldlen);
1274
1275         sysctl_unlock();
1276
1277         if (error && error != ENOMEM)
1278                 return (error);
1279
1280         if (retval) {
1281                 if (req.oldptr && req.oldidx > req.oldlen)
1282                         *retval = req.oldlen;
1283                 else
1284                         *retval = req.oldidx;
1285         }
1286         return (error);
1287 }
1288
1289 static void
1290 sysctl_lock(int flag)
1291 {
1292         lockmgr(&sysctl_lkp, flag);
1293 }
1294
1295 static void
1296 sysctl_unlock(void)
1297 {
1298         lockmgr(&sysctl_lkp, LK_RELEASE);
1299 }
1300
1301 static void
1302 sysctl_ctx_lock(int flag)
1303 {
1304         lockmgr(&sysctl_ctx_lkp, flag);
1305 }
1306
1307 static void
1308 sysctl_ctx_unlock(void)
1309 {
1310         lockmgr(&sysctl_ctx_lkp, LK_RELEASE);
1311 }
1312