kern_sysctl.c

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    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. Neither the name of the University nor the names of its contributors
   20  *    may be used to endorse or promote products derived from this software
   21  *    without specific prior written permission.
   22  *
   23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   33  * SUCH DAMAGE.
   34  *
   35  *      @(#)kern_sysctl.c       8.4 (Berkeley) 4/14/94
   36  * $FreeBSD: src/sys/kern/kern_sysctl.c,v 1.92.2.9 2003/05/01 22:48:09 trhodes Exp $
   37  */
   38 
   39 #include <sys/param.h>
   40 #include <sys/systm.h>
   41 #include <sys/kernel.h>
   42 #include <sys/buf.h>
   43 #include <sys/sysctl.h>
   44 #include <sys/malloc.h>
   45 #include <sys/proc.h>
   46 #include <sys/priv.h>
   47 #include <sys/sysproto.h>
   48 #include <sys/lock.h>
   49 
   50 #include <sys/mplock2.h>
   51 
   52 #include <vm/vm.h>
   53 #include <vm/vm_extern.h>
   54 
   55 static MALLOC_DEFINE(M_SYSCTL, "sysctl", "sysctl internal magic");
   56 static MALLOC_DEFINE(M_SYSCTLOID, "sysctloid", "sysctl dynamic oids");
   57 
   58 static struct lock sysctl_lkp;
   59 static struct lock sysctl_ctx_lkp;
   60 
   61 static void     sysctl_lock(int type);
   62 static void     sysctl_unlock(void);
   63 static void     sysctl_ctx_lock(int type);
   64 static void     sysctl_ctx_unlock(void);
   65 
   66 static int      sysctl_root(SYSCTL_HANDLER_ARGS);
   67 static void     sysctl_register_oid_int(struct sysctl_oid *oipd);
   68 static void     sysctl_unregister_oid_int(struct sysctl_oid *oipd);
   69 static struct sysctl_ctx_entry* sysctl_ctx_entry_find_int
   70         (struct sysctl_ctx_list *, struct sysctl_oid *oidp);
   71 
   72 struct sysctl_oid_list sysctl__children; /* root list */
   73 
   74 static struct sysctl_oid *
   75 sysctl_find_oidname(const char *name, struct sysctl_oid_list *list, int lock)
   76 {
   77         struct sysctl_oid *oidp;
   78 
   79         SLIST_FOREACH(oidp, list, oid_link) {
   80                 if (strcmp(oidp->oid_name, name) == 0) {
   81                         break;
   82                 }
   83         }
   84         return (oidp);
   85 }
   86 
   87 /*
   88  * Initialization of the MIB tree.
   89  *
   90  * Order by number in each list.
   91  */
   92 
   93 void
   94 sysctl_register_oid(struct sysctl_oid *oidp)
   95 {
   96         sysctl_lock(LK_EXCLUSIVE);
   97         sysctl_register_oid_int(oidp);
   98         sysctl_unlock();
   99 }
  100 
  101 static void
  102 sysctl_register_oid_int(struct sysctl_oid *oidp)
  103 {
  104         struct sysctl_oid_list *parent = oidp->oid_parent;
  105         struct sysctl_oid *p;
  106         struct sysctl_oid *q;
  107 
  108         /*
  109          * First check if another oid with the same name already
  110          * exists in the parent's list.
  111          */
  112         p = sysctl_find_oidname(oidp->oid_name, parent, 0);
  113         if (p != NULL) {
  114                 if ((p->oid_kind & CTLTYPE) == CTLTYPE_NODE)
  115                         p->oid_refcnt++;
  116                 else
  117                         kprintf("can't re-use a leaf (%s)!\n", p->oid_name);
  118                 return;
  119         }
  120 
  121         /*
  122          * If this oid has a number OID_AUTO, give it a number which
  123          * is greater than any current oid.  Make sure it is at least
  124          * 256 to leave space for pre-assigned oid numbers.
  125          */
  126         if (oidp->oid_number == OID_AUTO) {
  127                 int newoid = 0x100;     /* minimum AUTO oid */
  128 
  129                 /*
  130                  * Adjust based on highest oid in parent list
  131                  */
  132                 SLIST_FOREACH(p, parent, oid_link) {
  133                         if (newoid <= p->oid_number)
  134                                 newoid = p->oid_number + 1;
  135                 }
  136                 oidp->oid_number = newoid;
  137         }
  138 
  139         /*
  140          * Insert the oid into the parent's list in order.
  141          */
  142         q = NULL;
  143         SLIST_FOREACH(p, parent, oid_link) {
  144                 if (oidp->oid_number < p->oid_number)
  145                         break;
  146                 q = p;
  147         }
  148         if (q)
  149                 SLIST_INSERT_AFTER(q, oidp, oid_link);
  150         else
  151                 SLIST_INSERT_HEAD(parent, oidp, oid_link);
  152 }
  153 
  154 void
  155 sysctl_unregister_oid(struct sysctl_oid *oidp)
  156 {
  157         sysctl_lock(LK_EXCLUSIVE);
  158         sysctl_unregister_oid_int(oidp);
  159         sysctl_unlock();
  160 }
  161 
  162 static void
  163 sysctl_unregister_oid_int(struct sysctl_oid *oidp)
  164 {
  165         struct sysctl_oid *p;
  166 
  167         if (oidp->oid_number == OID_AUTO)
  168                 panic("Trying to unregister OID_AUTO entry: %p", oidp);
  169 
  170         SLIST_FOREACH(p, oidp->oid_parent, oid_link) {
  171                 if (p != oidp)
  172                         continue;
  173                 SLIST_REMOVE(oidp->oid_parent, oidp, sysctl_oid, oid_link);
  174                 return;
  175         }
  176 
  177         /*
  178          * This can happen when a module fails to register and is
  179          * being unloaded afterwards.  It should not be a panic()
  180          * for normal use.
  181          */
  182         kprintf("%s: failed to unregister sysctl\n", __func__);
  183 }
  184 
  185 /* Initialize a new context to keep track of dynamically added sysctls. */
  186 int
  187 sysctl_ctx_init(struct sysctl_ctx_list *c)
  188 {
  189         if (c == NULL)
  190                 return(EINVAL);
  191         TAILQ_INIT(c);
  192         return(0);
  193 }
  194 
  195 /* Free the context, and destroy all dynamic oids registered in this context */
  196 int
  197 sysctl_ctx_free(struct sysctl_ctx_list *clist)
  198 {
  199         struct sysctl_ctx_entry *e, *e1;
  200         int error;
  201 
  202         error = 0;
  203         sysctl_ctx_lock(LK_EXCLUSIVE);
  204         /*
  205          * First perform a "dry run" to check if it's ok to remove oids.
  206          * XXX FIXME
  207          * XXX This algorithm is a hack. But I don't know any
  208          * XXX better solution for now...
  209          */
  210         TAILQ_FOREACH(e, clist, link) {
  211                 error = sysctl_remove_oid(e->entry, 0, 0);
  212                 if (error)
  213                         break;
  214         }
  215         /*
  216          * Restore deregistered entries, either from the end,
  217          * or from the place where error occured.
  218          * e contains the entry that was not unregistered
  219          */
  220         if (error)
  221                 e1 = TAILQ_PREV(e, sysctl_ctx_list, link);
  222         else
  223                 e1 = TAILQ_LAST(clist, sysctl_ctx_list);
  224         while (e1 != NULL) {
  225                 sysctl_register_oid(e1->entry);
  226                 e1 = TAILQ_PREV(e1, sysctl_ctx_list, link);
  227         }
  228         if (error) {
  229                 sysctl_ctx_unlock();
  230                 return(EBUSY);
  231         }
  232         /* Now really delete the entries */
  233         e = TAILQ_FIRST(clist);
  234         while (e != NULL) {
  235                 e1 = TAILQ_NEXT(e, link);
  236                 error = sysctl_remove_oid(e->entry, 1, 0);
  237                 if (error)
  238                         panic("sysctl_remove_oid: corrupt tree, entry: %s",
  239                             e->entry->oid_name);
  240                 kfree(e, M_SYSCTLOID);
  241                 e = e1;
  242         }
  243         sysctl_ctx_unlock();
  244         return (error);
  245 }
  246 
  247 /* Add an entry to the context */
  248 struct sysctl_ctx_entry *
  249 sysctl_ctx_entry_add(struct sysctl_ctx_list *clist, struct sysctl_oid *oidp)
  250 {
  251         struct sysctl_ctx_entry *e;
  252 
  253         if (clist == NULL || oidp == NULL)
  254                 return(NULL);
  255         e = kmalloc(sizeof(struct sysctl_ctx_entry), M_SYSCTLOID, M_WAITOK);
  256         e->entry = oidp;
  257         sysctl_ctx_lock(LK_EXCLUSIVE);
  258         TAILQ_INSERT_HEAD(clist, e, link);
  259         sysctl_ctx_unlock();
  260         return (e);
  261 }
  262 
  263 /* Find an entry in the context */
  264 struct sysctl_ctx_entry *
  265 sysctl_ctx_entry_find(struct sysctl_ctx_list *clist, struct sysctl_oid *oidp)
  266 {
  267         struct sysctl_ctx_entry *e;
  268 
  269         if (clist == NULL || oidp == NULL)
  270                 return(NULL);
  271 
  272         sysctl_ctx_lock(LK_SHARED);
  273         e = sysctl_ctx_entry_find_int(clist, oidp);
  274         sysctl_ctx_unlock();
  275 
  276         return(e);
  277 }
  278 
  279 struct sysctl_ctx_entry *
  280 sysctl_ctx_entry_find_int(struct sysctl_ctx_list *clist, struct sysctl_oid *oidp)
  281 {
  282         struct sysctl_ctx_entry *e;
  283 
  284         KKASSERT(clist != NULL && oidp != NULL);
  285 
  286         for (e = TAILQ_FIRST(clist); e != NULL; e = TAILQ_NEXT(e, link)) {
  287                 if(e->entry == oidp)
  288                         break;
  289         }
  290 
  291         return (e);
  292 }
  293 
  294 /*
  295  * Delete an entry from the context.
  296  * NOTE: this function doesn't free oidp! You have to remove it
  297  * with sysctl_remove_oid().
  298  */
  299 int
  300 sysctl_ctx_entry_del(struct sysctl_ctx_list *clist, struct sysctl_oid *oidp)
  301 {
  302         struct sysctl_ctx_entry *e;
  303 
  304         if (clist == NULL || oidp == NULL)
  305                 return (EINVAL);
  306 
  307         sysctl_ctx_lock(LK_EXCLUSIVE);
  308         e = sysctl_ctx_entry_find_int(clist, oidp);
  309         if (e == NULL) {
  310                 sysctl_ctx_unlock();
  311                 return (ENOENT);
  312         }
  313         TAILQ_REMOVE(clist, e, link);
  314         kfree(e, M_SYSCTLOID);
  315         sysctl_ctx_unlock();
  316 
  317         return(0);
  318 }
  319 
  320 /*
  321  * Remove dynamically created sysctl trees.
  322  * oidp - top of the tree to be removed
  323  * del - if 0 - just deregister, otherwise free up entries as well
  324  * recurse - if != 0 traverse the subtree to be deleted
  325  */
  326 int
  327 sysctl_remove_oid(struct sysctl_oid *oidp, int del, int recurse)
  328 {
  329         struct sysctl_oid *p;
  330         int error;
  331 
  332         if (oidp == NULL)
  333                 return(EINVAL);
  334         if ((oidp->oid_kind & CTLFLAG_DYN) == 0) {
  335                 kprintf("can't remove non-dynamic nodes!\n");
  336                 return (EINVAL);
  337         }
  338         sysctl_lock(LK_EXCLUSIVE | LK_CANRECURSE);
  339         /*
  340          * WARNING: normal method to do this should be through
  341          * sysctl_ctx_free(). Use recursing as the last resort
  342          * method to purge your sysctl tree of leftovers...
  343          * However, if some other code still references these nodes,
  344          * it will panic.
  345          */
  346         if ((oidp->oid_kind & CTLTYPE) == CTLTYPE_NODE) {
  347                 if (oidp->oid_refcnt == 1) {
  348                         SLIST_FOREACH(p, SYSCTL_CHILDREN(oidp), oid_link) {
  349                                 if (!recurse) {
  350                                         sysctl_unlock();
  351                                         return(ENOTEMPTY);
  352                                 }
  353                                 error = sysctl_remove_oid(p, del, recurse);
  354                                 if (error) {
  355                                         sysctl_unlock();
  356                                         return(error);
  357                                 }
  358                         }
  359                         if (del)
  360                                 kfree(SYSCTL_CHILDREN(oidp), M_SYSCTLOID);
  361                 }
  362         }
  363         if (oidp->oid_refcnt > 1 ) {
  364                 oidp->oid_refcnt--;
  365         } else {
  366                 if (oidp->oid_refcnt == 0) {
  367                         kprintf("Warning: bad oid_refcnt=%u (%s)!\n",
  368                                oidp->oid_refcnt, oidp->oid_name);
  369                         sysctl_unlock();
  370                         return(EINVAL);
  371                 }
  372                 sysctl_unregister_oid_int(oidp);
  373                 if (del) {
  374                         if (oidp->oid_descr)
  375                                 kfree(__DECONST(char *,oidp->oid_descr),
  376                                      M_SYSCTLOID);
  377                         kfree(__DECONST(char *, oidp->oid_name), M_SYSCTLOID);
  378                         kfree(oidp, M_SYSCTLOID);
  379                 }
  380         }
  381         sysctl_unlock();
  382         return(0);
  383 }
  384 
  385 /*
  386  * Create new sysctls at run time.
  387  * clist may point to a valid context initialized with sysctl_ctx_init().
  388  */
  389 struct sysctl_oid *
  390 sysctl_add_oid(struct sysctl_ctx_list *clist, struct sysctl_oid_list *parent,
  391         int number, const char *name, int kind, void *arg1, int arg2,
  392         int (*handler)(SYSCTL_HANDLER_ARGS), const char *fmt, const char *descr)
  393 {
  394         struct sysctl_oid *oidp;
  395         ssize_t len;
  396         char *newname;
  397 
  398         /* You have to hook up somewhere.. */
  399         if (parent == NULL)
  400                 return(NULL);
  401         sysctl_lock(LK_EXCLUSIVE);
  402         /* Check if the node already exists, otherwise create it */
  403         oidp = sysctl_find_oidname(name, parent, 0);
  404         if (oidp != NULL) {
  405                 if ((oidp->oid_kind & CTLTYPE) == CTLTYPE_NODE) {
  406                         oidp->oid_refcnt++;
  407                         /* Update the context */
  408                         if (clist != NULL)
  409                                 sysctl_ctx_entry_add(clist, oidp);
  410                         sysctl_unlock();
  411                         return (oidp);
  412                 } else {
  413                         kprintf("can't re-use a leaf (%s)!\n", name);
  414                         sysctl_unlock();
  415                         return (NULL);
  416                 }
  417         }
  418         oidp = kmalloc(sizeof(struct sysctl_oid), M_SYSCTLOID, M_WAITOK | M_ZERO);
  419         oidp->oid_parent = parent;
  420         SLIST_NEXT(oidp, oid_link) = NULL;
  421         oidp->oid_number = number;
  422         oidp->oid_refcnt = 1;
  423         len = strlen(name);
  424         newname = kmalloc(len + 1, M_SYSCTLOID, M_WAITOK);
  425         bcopy(name, newname, len + 1);
  426         newname[len] = '\0';
  427         oidp->oid_name = newname;
  428         oidp->oid_handler = handler;
  429         oidp->oid_kind = CTLFLAG_DYN | kind;
  430         if ((kind & CTLTYPE) == CTLTYPE_NODE) {
  431                 struct sysctl_oid_list *children;
  432 
  433                 /* Allocate space for children */
  434                 children = kmalloc(sizeof(*children), M_SYSCTLOID, M_WAITOK);
  435                 SYSCTL_SET_CHILDREN(oidp, children);
  436                 SLIST_INIT(children);
  437         } else {
  438                 oidp->oid_arg1 = arg1;
  439                 oidp->oid_arg2 = arg2;
  440         }
  441         oidp->oid_fmt = fmt;
  442         if (descr) {
  443                 int len = strlen(descr) + 1;
  444                 oidp->oid_descr = kmalloc(len, M_SYSCTLOID, M_WAITOK);
  445                 strcpy((char *)(uintptr_t)(const void *)oidp->oid_descr, descr);
  446         };
  447         /* Update the context, if used */
  448         if (clist != NULL)
  449                 sysctl_ctx_entry_add(clist, oidp);
  450         /* Register this oid */
  451         sysctl_register_oid_int(oidp);
  452         sysctl_unlock();
  453         return (oidp);
  454 }
  455 
  456 /*
  457  * Register the kernel's oids on startup.
  458  */
  459 SET_DECLARE(sysctl_set, struct sysctl_oid);
  460 
  461 static void
  462 sysctl_register_all(void *arg)
  463 {
  464         struct sysctl_oid **oidp;
  465 
  466         lockinit(&sysctl_lkp, "sysctl", 0, 0);
  467         lockinit(&sysctl_ctx_lkp, "sysctl ctx", 0, 0);
  468         SET_FOREACH(oidp, sysctl_set)
  469                 sysctl_register_oid_int(*oidp);
  470 }
  471 
  472 SYSINIT(sysctl, SI_BOOT1_POST, SI_ORDER_ANY, sysctl_register_all, 0);
  473 
  474 /*
  475  * "Staff-functions"
  476  *
  477  * These functions implement a presently undocumented interface 
  478  * used by the sysctl program to walk the tree, and get the type
  479  * so it can print the value.
  480  * This interface is under work and consideration, and should probably
  481  * be killed with a big axe by the first person who can find the time.
  482  * (be aware though, that the proper interface isn't as obvious as it
  483  * may seem, there are various conflicting requirements.
  484  *
  485  * {0,0}        kprintf the entire MIB-tree.
  486  * {0,1,...}    return the name of the "..." OID.
  487  * {0,2,...}    return the next OID.
  488  * {0,3}        return the OID of the name in "new"
  489  * {0,4,...}    return the kind & format info for the "..." OID.
  490  */
  491 
  492 static void
  493 sysctl_sysctl_debug_dump_node(struct sysctl_oid_list *l, int i)
  494 {
  495         int k;
  496         struct sysctl_oid *oidp;
  497 
  498         sysctl_lock(LK_SHARED);
  499         SLIST_FOREACH(oidp, l, oid_link) {
  500 
  501                 for (k=0; k<i; k++)
  502                         kprintf(" ");
  503 
  504                 kprintf("%d %s ", oidp->oid_number, oidp->oid_name);
  505 
  506                 kprintf("%c%c",
  507                         oidp->oid_kind & CTLFLAG_RD ? 'R':' ',
  508                         oidp->oid_kind & CTLFLAG_WR ? 'W':' ');
  509 
  510                 if (oidp->oid_handler)
  511                         kprintf(" *Handler");
  512 
  513                 switch (oidp->oid_kind & CTLTYPE) {
  514                         case CTLTYPE_NODE:
  515                                 kprintf(" Node\n");
  516                                 if (!oidp->oid_handler) {
  517                                         sysctl_sysctl_debug_dump_node(
  518                                                 oidp->oid_arg1, i+2);
  519                                 }
  520                                 break;
  521                         case CTLTYPE_INT:    kprintf(" Int\n"); break;
  522                         case CTLTYPE_STRING: kprintf(" String\n"); break;
  523                         case CTLTYPE_QUAD:   kprintf(" Quad\n"); break;
  524                         case CTLTYPE_OPAQUE: kprintf(" Opaque/struct\n"); break;
  525                         default:             kprintf("\n");
  526                 }
  527 
  528         }
  529         sysctl_unlock();
  530 }
  531 
  532 static int
  533 sysctl_sysctl_debug(SYSCTL_HANDLER_ARGS)
  534 {
  535         int error;
  536 
  537         error = priv_check(req->td, PRIV_SYSCTL_DEBUG);
  538         if (error)
  539                 return error;
  540         sysctl_sysctl_debug_dump_node(&sysctl__children, 0);
  541         return ENOENT;
  542 }
  543 
  544 SYSCTL_PROC(_sysctl, 0, debug, CTLTYPE_STRING|CTLFLAG_RD,
  545         0, 0, sysctl_sysctl_debug, "-", "");
  546 
  547 static int
  548 sysctl_sysctl_name(SYSCTL_HANDLER_ARGS)
  549 {
  550         int *name = (int *) arg1;
  551         u_int namelen = arg2;
  552         int error = 0;
  553         struct sysctl_oid *oid;
  554         struct sysctl_oid_list *lsp = &sysctl__children, *lsp2;
  555         char buf[16];
  556 
  557         sysctl_lock(LK_SHARED);
  558         while (namelen) {
  559                 if (!lsp) {
  560                         ksnprintf(buf, sizeof(buf), "%d", *name);
  561                         if (req->oldidx)
  562                                 error = SYSCTL_OUT(req, ".", 1);
  563                         if (!error)
  564                                 error = SYSCTL_OUT(req, buf, strlen(buf));
  565                         if (error) {
  566                                 sysctl_unlock();
  567                                 return (error);
  568                         }
  569                         namelen--;
  570                         name++;
  571                         continue;
  572                 }
  573                 lsp2 = NULL;
  574                 SLIST_FOREACH(oid, lsp, oid_link) {
  575                         if (oid->oid_number != *name)
  576                                 continue;
  577 
  578                         if (req->oldidx)
  579                                 error = SYSCTL_OUT(req, ".", 1);
  580                         if (!error)
  581                                 error = SYSCTL_OUT(req, oid->oid_name,
  582                                         strlen(oid->oid_name));
  583                         if (error) {
  584                                 sysctl_unlock();
  585                                 return (error);
  586                         }
  587 
  588                         namelen--;
  589                         name++;
  590 
  591                         if ((oid->oid_kind & CTLTYPE) != CTLTYPE_NODE) 
  592                                 break;
  593 
  594                         if (oid->oid_handler)
  595                                 break;
  596 
  597                         lsp2 = (struct sysctl_oid_list *)oid->oid_arg1;
  598                         break;
  599                 }
  600                 lsp = lsp2;
  601         }
  602         sysctl_unlock();
  603         return (SYSCTL_OUT(req, "", 1));
  604 }
  605 
  606 SYSCTL_NODE(_sysctl, 1, name, CTLFLAG_RD, sysctl_sysctl_name, "");
  607 
  608 static int
  609 sysctl_sysctl_next_ls(struct sysctl_oid_list *lsp, int *name, u_int namelen, 
  610         int *next, int *len, int level, struct sysctl_oid **oidpp)
  611 {
  612         struct sysctl_oid *oidp;
  613 
  614         *len = level;
  615         sysctl_lock(LK_SHARED);
  616         SLIST_FOREACH(oidp, lsp, oid_link) {
  617                 *next = oidp->oid_number;
  618                 *oidpp = oidp;
  619 
  620                 if (!namelen) {
  621                         if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE) {
  622                                 sysctl_unlock();
  623                                 return 0;
  624                         }
  625                         if (oidp->oid_handler) {
  626                                 /* We really should call the handler here...*/
  627                                 sysctl_unlock();
  628                                 return 0;
  629                         }
  630                         lsp = (struct sysctl_oid_list *)oidp->oid_arg1;
  631                         if (!sysctl_sysctl_next_ls(lsp, 0, 0, next+1, 
  632                                 len, level+1, oidpp)) {
  633                                 sysctl_unlock();
  634                                 return 0;
  635                         }
  636                         goto emptynode;
  637                 }
  638 
  639                 if (oidp->oid_number < *name)
  640                         continue;
  641 
  642                 if (oidp->oid_number > *name) {
  643                         if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE) {
  644                                 sysctl_unlock();
  645                                 return 0;
  646                         }
  647                         if (oidp->oid_handler) {
  648                                 sysctl_unlock();
  649                                 return 0;
  650                         }
  651                         lsp = (struct sysctl_oid_list *)oidp->oid_arg1;
  652                         if (!sysctl_sysctl_next_ls(lsp, name+1, namelen-1, 
  653                                 next+1, len, level+1, oidpp)) {
  654                                 sysctl_unlock();
  655                                 return (0);
  656                         }
  657                         goto next;
  658                 }
  659                 if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE)
  660                         continue;
  661 
  662                 if (oidp->oid_handler)
  663                         continue;
  664 
  665                 lsp = (struct sysctl_oid_list *)oidp->oid_arg1;
  666                 if (!sysctl_sysctl_next_ls(lsp, name+1, namelen-1, next+1, 
  667                         len, level+1, oidpp)) {
  668                         sysctl_unlock();
  669                         return (0);
  670                 }
  671         next:
  672                 namelen = 1;
  673                 *len = level;
  674         emptynode:
  675                 *len = level;
  676         }
  677         sysctl_unlock();
  678         return 1;
  679 }
  680 
  681 static int
  682 sysctl_sysctl_next(SYSCTL_HANDLER_ARGS)
  683 {
  684         int *name = (int *) arg1;
  685         u_int namelen = arg2;
  686         int i, j, error;
  687         struct sysctl_oid *oid;
  688         struct sysctl_oid_list *lsp = &sysctl__children;
  689         int newoid[CTL_MAXNAME];
  690 
  691         i = sysctl_sysctl_next_ls(lsp, name, namelen, newoid, &j, 1, &oid);
  692         if (i)
  693                 return ENOENT;
  694         error = SYSCTL_OUT(req, newoid, j * sizeof (int));
  695         return (error);
  696 }
  697 
  698 SYSCTL_NODE(_sysctl, 2, next, CTLFLAG_RD, sysctl_sysctl_next, "");
  699 
  700 static int
  701 name2oid (char *name, int *oid, int *len, struct sysctl_oid **oidpp)
  702 {
  703         int i;
  704         struct sysctl_oid *oidp;
  705         struct sysctl_oid_list *lsp = &sysctl__children;
  706         char *p;
  707 
  708         if (!*name)
  709                 return ENOENT;
  710 
  711         p = name + strlen(name) - 1 ;
  712         if (*p == '.')
  713                 *p = '\0';
  714 
  715         *len = 0;
  716 
  717         for (p = name; *p && *p != '.'; p++) 
  718                 ;
  719         i = *p;
  720         if (i == '.')
  721                 *p = '\0';
  722 
  723         sysctl_lock(LK_SHARED);
  724         oidp = SLIST_FIRST(lsp);
  725 
  726         while (oidp && *len < CTL_MAXNAME) {
  727                 if (strcmp(name, oidp->oid_name)) {
  728                         oidp = SLIST_NEXT(oidp, oid_link);
  729                         continue;
  730                 }
  731                 *oid++ = oidp->oid_number;
  732                 (*len)++;
  733 
  734                 if (!i) {
  735                         if (oidpp)
  736                                 *oidpp = oidp;
  737                         sysctl_unlock();
  738                         return (0);
  739                 }
  740 
  741                 if ((oidp->oid_kind & CTLTYPE) != CTLTYPE_NODE)
  742                         break;
  743 
  744                 if (oidp->oid_handler)
  745                         break;
  746 
  747                 lsp = (struct sysctl_oid_list *)oidp->oid_arg1;
  748                 oidp = SLIST_FIRST(lsp);
  749                 name = p+1;
  750                 for (p = name; *p && *p != '.'; p++) 
  751                                 ;
  752                 i = *p;
  753                 if (i == '.')
  754                         *p = '\0';
  755         }
  756         sysctl_unlock();
  757         return ENOENT;
  758 }
  759 
  760 static int
  761 sysctl_sysctl_name2oid(SYSCTL_HANDLER_ARGS)
  762 {
  763         char *p;
  764         int error, oid[CTL_MAXNAME], len;
  765         struct sysctl_oid *op = NULL;
  766 
  767         if (!req->newlen) 
  768                 return ENOENT;
  769         if (req->newlen >= MAXPATHLEN)  /* XXX arbitrary, undocumented */
  770                 return (ENAMETOOLONG);
  771 
  772         p = kmalloc(req->newlen+1, M_SYSCTL, M_WAITOK);
  773 
  774         error = SYSCTL_IN(req, p, req->newlen);
  775         if (error) {
  776                 kfree(p, M_SYSCTL);
  777                 return (error);
  778         }
  779 
  780         p [req->newlen] = '\0';
  781 
  782         error = name2oid(p, oid, &len, &op);
  783 
  784         kfree(p, M_SYSCTL);
  785 
  786         if (error)
  787                 return (error);
  788 
  789         error = SYSCTL_OUT(req, oid, len * sizeof *oid);
  790         return (error);
  791 }
  792 
  793 SYSCTL_PROC(_sysctl, 3, name2oid, CTLFLAG_RW|CTLFLAG_ANYBODY, 0, 0, 
  794         sysctl_sysctl_name2oid, "I", "");
  795 
  796 static int
  797 sysctl_sysctl_oidfmt(SYSCTL_HANDLER_ARGS)
  798 {
  799         struct sysctl_oid *oid;
  800         int error;
  801 
  802         error = sysctl_find_oid(arg1, arg2, &oid, NULL, req);
  803         if (error)
  804                 return (error);
  805 
  806         if (!oid->oid_fmt)
  807                 return (ENOENT);
  808         error = SYSCTL_OUT(req, &oid->oid_kind, sizeof(oid->oid_kind));
  809         if (error)
  810                 return (error);
  811         error = SYSCTL_OUT(req, oid->oid_fmt, strlen(oid->oid_fmt) + 1);
  812         return (error);
  813 }
  814 
  815 
  816 SYSCTL_NODE(_sysctl, 4, oidfmt, CTLFLAG_RD, sysctl_sysctl_oidfmt, "");
  817 
  818 static int
  819 sysctl_sysctl_oiddescr(SYSCTL_HANDLER_ARGS)
  820 {
  821         struct sysctl_oid *oid;
  822         int error;
  823 
  824         error = sysctl_find_oid(arg1, arg2, &oid, NULL, req);
  825         if (error)
  826                 return (error);
  827         
  828         if (!oid->oid_descr)
  829                 return (ENOENT);
  830         error = SYSCTL_OUT(req, oid->oid_descr, strlen(oid->oid_descr) + 1);
  831         return (error);
  832 }
  833 
  834 SYSCTL_NODE(_sysctl, 5, oiddescr, CTLFLAG_RD, sysctl_sysctl_oiddescr, "");
  835 
  836 /*
  837  * Default "handler" functions.
  838  */
  839 
  840 /*
  841  * Handle an int, signed or unsigned.
  842  * Two cases:
  843  *     a variable:  point arg1 at it.
  844  *     a constant:  pass it in arg2.
  845  */
  846 
  847 int
  848 sysctl_handle_int(SYSCTL_HANDLER_ARGS)
  849 {
  850         int error = 0;
  851 
  852         if (arg1)
  853                 error = SYSCTL_OUT(req, arg1, sizeof(int));
  854         else
  855                 error = SYSCTL_OUT(req, &arg2, sizeof(int));
  856 
  857         if (error || !req->newptr)
  858                 return (error);
  859 
  860         if (!arg1)
  861                 error = EPERM;
  862         else
  863                 error = SYSCTL_IN(req, arg1, sizeof(int));
  864         return (error);
  865 }
  866 
  867 /*
  868  * Handle a long, signed or unsigned.  arg1 points to it.
  869  */
  870 
  871 int
  872 sysctl_handle_long(SYSCTL_HANDLER_ARGS)
  873 {
  874         int error = 0;
  875 
  876         if (!arg1)
  877                 return (EINVAL);
  878         error = SYSCTL_OUT(req, arg1, sizeof(long));
  879 
  880         if (error || !req->newptr)
  881                 return (error);
  882 
  883         error = SYSCTL_IN(req, arg1, sizeof(long));
  884         return (error);
  885 }
  886 
  887 /*
  888  * Handle a quad, signed or unsigned.  arg1 points to it.
  889  */
  890 
  891 int
  892 sysctl_handle_quad(SYSCTL_HANDLER_ARGS)
  893 {
  894         int error = 0;
  895 
  896         if (!arg1)
  897                 return (EINVAL);
  898         error = SYSCTL_OUT(req, arg1, sizeof(quad_t));
  899 
  900         if (error || !req->newptr)
  901                 return (error);
  902 
  903         error = SYSCTL_IN(req, arg1, sizeof(quad_t));
  904         return (error);
  905 }
  906 
  907 /*
  908  * Handle our generic '\0' terminated 'C' string.
  909  * Two cases:
  910  *      a variable string:  point arg1 at it, arg2 is max length.
  911  *      a constant string:  point arg1 at it, arg2 is zero.
  912  */
  913 
  914 int
  915 sysctl_handle_string(SYSCTL_HANDLER_ARGS)
  916 {
  917         int error=0;
  918 
  919         error = SYSCTL_OUT(req, arg1, strlen((char *)arg1)+1);
  920 
  921         if (error || !req->newptr)
  922                 return (error);
  923 
  924         if ((req->newlen - req->newidx) >= arg2) {
  925                 error = EINVAL;
  926         } else {
  927                 arg2 = (req->newlen - req->newidx);
  928                 error = SYSCTL_IN(req, arg1, arg2);
  929                 ((char *)arg1)[arg2] = '\0';
  930         }
  931 
  932         return (error);
  933 }
  934 
  935 /*
  936  * Handle any kind of opaque data.
  937  * arg1 points to it, arg2 is the size.
  938  */
  939 
  940 int
  941 sysctl_handle_opaque(SYSCTL_HANDLER_ARGS)
  942 {
  943         int error;
  944 
  945         error = SYSCTL_OUT(req, arg1, arg2);
  946 
  947         if (error || !req->newptr)
  948                 return (error);
  949 
  950         error = SYSCTL_IN(req, arg1, arg2);
  951 
  952         return (error);
  953 }
  954 
  955 /*
  956  * Transfer functions to/from kernel space.
  957  * XXX: rather untested at this point
  958  */
  959 static int
  960 sysctl_old_kernel(struct sysctl_req *req, const void *p, size_t l)
  961 {
  962         size_t i = 0;
  963 
  964         if (req->oldptr) {
  965                 i = l;
  966                 if (i > req->oldlen - req->oldidx)
  967                         i = req->oldlen - req->oldidx;
  968                 if (i > 0)
  969                         bcopy(p, (char *)req->oldptr + req->oldidx, i);
  970         }
  971         req->oldidx += l;
  972         if (req->oldptr && i != l)
  973                 return (ENOMEM);
  974         return (0);
  975 }
  976 
  977 static int
  978 sysctl_new_kernel(struct sysctl_req *req, void *p, size_t l)
  979 {
  980 
  981         if (!req->newptr)
  982                 return 0;
  983         if (req->newlen - req->newidx < l)
  984                 return (EINVAL);
  985         bcopy((char *)req->newptr + req->newidx, p, l);
  986         req->newidx += l;
  987         return (0);
  988 }
  989 
  990 int
  991 kernel_sysctl(int *name, u_int namelen, void *old, size_t *oldlenp, void *new, size_t newlen, size_t *retval)
  992 {
  993         int error = 0;
  994         struct sysctl_req req;
  995 
  996         bzero(&req, sizeof req);
  997 
  998         req.td = curthread;
  999 
 1000         if (oldlenp) {
 1001                 req.oldlen = *oldlenp;
 1002         }
 1003 
 1004         if (old) {
 1005                 req.oldptr = old;
 1006         }
 1007 
 1008         if (new != NULL) {
 1009                 req.newlen = newlen;
 1010                 req.newptr = new;
 1011         }
 1012 
 1013         req.oldfunc = sysctl_old_kernel;
 1014         req.newfunc = sysctl_new_kernel;
 1015 #if 0
 1016         req.lock = 1;
 1017 #endif
 1018 
 1019         sysctl_lock(LK_SHARED);
 1020 
 1021         error = sysctl_root(0, name, namelen, &req);
 1022 
 1023 #if 0
 1024         if (req.lock == 2)
 1025                 vsunlock(req.oldptr, req.oldlen);
 1026 #endif
 1027 
 1028         sysctl_unlock();
 1029 
 1030         if (error && error != ENOMEM)
 1031                 return (error);
 1032 
 1033         if (retval) {
 1034                 if (req.oldptr && req.oldidx > req.oldlen)
 1035                         *retval = req.oldlen;
 1036                 else
 1037                         *retval = req.oldidx;
 1038         }
 1039         return (error);
 1040 }
 1041 
 1042 int
 1043 kernel_sysctlbyname(char *name, void *old, size_t *oldlenp,
 1044     void *new, size_t newlen, size_t *retval)
 1045 {
 1046         int oid[CTL_MAXNAME];
 1047         size_t oidlen, plen;
 1048         int error;
 1049 
 1050         oid[0] = 0;             /* sysctl internal magic */
 1051         oid[1] = 3;             /* name2oid */
 1052         oidlen = sizeof(oid);
 1053 
 1054         error = kernel_sysctl(oid, 2, oid, &oidlen, name, strlen(name), &plen);
 1055         if (error)
 1056                 return (error);
 1057 
 1058         error = kernel_sysctl(oid, plen / sizeof(int), old, oldlenp,
 1059             new, newlen, retval);
 1060         return (error);
 1061 }
 1062 
 1063 /*
 1064  * Transfer function to/from user space.
 1065  */
 1066 static int
 1067 sysctl_old_user(struct sysctl_req *req, const void *p, size_t l)
 1068 {
 1069         int error = 0;
 1070         size_t i = 0;
 1071 
 1072 #if 0
 1073         if (req->lock == 1 && req->oldptr) {
 1074                 vslock(req->oldptr, req->oldlen);
 1075                 req->lock = 2;
 1076         }
 1077 #endif
 1078         if (req->oldptr) {
 1079                 i = l;
 1080                 if (i > req->oldlen - req->oldidx)
 1081                         i = req->oldlen - req->oldidx;
 1082                 if (i > 0)
 1083                         error = copyout(p, (char *)req->oldptr + req->oldidx,
 1084                                         i);
 1085         }
 1086         req->oldidx += l;
 1087         if (error)
 1088                 return (error);
 1089         if (req->oldptr && i < l)
 1090                 return (ENOMEM);
 1091         return (0);
 1092 }
 1093 
 1094 static int
 1095 sysctl_new_user(struct sysctl_req *req, void *p, size_t l)
 1096 {
 1097         int error;
 1098 
 1099         if (!req->newptr)
 1100                 return 0;
 1101         if (req->newlen - req->newidx < l)
 1102                 return (EINVAL);
 1103         error = copyin((char *)req->newptr + req->newidx, p, l);
 1104         req->newidx += l;
 1105         return (error);
 1106 }
 1107 
 1108 int
 1109 sysctl_find_oid(int *name, u_int namelen, struct sysctl_oid **noid,
 1110     int *nindx, struct sysctl_req *req)
 1111 {
 1112         struct sysctl_oid *oid;
 1113         int indx;
 1114 
 1115         sysctl_lock(LK_SHARED);
 1116         oid = SLIST_FIRST(&sysctl__children);
 1117         indx = 0;
 1118         while (oid && indx < CTL_MAXNAME) {
 1119                 if (oid->oid_number == name[indx]) {
 1120                         indx++;
 1121                         if ((oid->oid_kind & CTLTYPE) == CTLTYPE_NODE) {
 1122                                 if (oid->oid_handler != NULL ||
 1123                                     indx == namelen) {
 1124                                         *noid = oid;
 1125                                         if (nindx != NULL)
 1126                                                 *nindx = indx;
 1127                                         sysctl_unlock();
 1128                                         return (0);
 1129                                 }
 1130                                 oid = SLIST_FIRST(
 1131                                     (struct sysctl_oid_list *)oid->oid_arg1);
 1132                         } else if (indx == namelen) {
 1133                                 *noid = oid;
 1134                                 if (nindx != NULL)
 1135                                         *nindx = indx;
 1136                                 sysctl_unlock();
 1137                                 return (0);
 1138                         } else {
 1139                                 sysctl_unlock();
 1140                                 return (ENOTDIR);
 1141                         }
 1142                 } else {
 1143                         oid = SLIST_NEXT(oid, oid_link);
 1144                 }
 1145         }
 1146         sysctl_unlock();
 1147         return (ENOENT);
 1148 }
 1149 
 1150 /*
 1151  * Traverse our tree, and find the right node, execute whatever it points
 1152  * to, and return the resulting error code.
 1153  */
 1154 
 1155 int
 1156 sysctl_root(SYSCTL_HANDLER_ARGS)
 1157 {
 1158         struct thread *td = req->td;
 1159         struct proc *p = td ? td->td_proc : NULL;
 1160         struct sysctl_oid *oid;
 1161         int error, indx;
 1162 
 1163         error = sysctl_find_oid(arg1, arg2, &oid, &indx, req);
 1164         if (error)
 1165                 return (error);
 1166 
 1167         if ((oid->oid_kind & CTLTYPE) == CTLTYPE_NODE) {
 1168                 /*
 1169                  * You can't call a sysctl when it's a node, but has
 1170                  * no handler.  Inform the user that it's a node.
 1171                  * The indx may or may not be the same as namelen.
 1172                  */
 1173                 if (oid->oid_handler == NULL)
 1174                         return (EISDIR);
 1175         }
 1176 
 1177         /* If writing isn't allowed */
 1178         if (req->newptr && (!(oid->oid_kind & CTLFLAG_WR) ||
 1179             ((oid->oid_kind & CTLFLAG_SECURE) && securelevel > 0)))
 1180                 return (EPERM);
 1181 
 1182         /* Most likely only root can write */
 1183         if (!(oid->oid_kind & CTLFLAG_ANYBODY) && req->newptr && p &&
 1184             (error = priv_check_cred(td->td_ucred,
 1185              (oid->oid_kind & CTLFLAG_PRISON) ? PRIV_SYSCTL_WRITEJAIL :
 1186                                                 PRIV_SYSCTL_WRITE, 0)))
 1187                 return (error);
 1188 
 1189         if (!oid->oid_handler)
 1190                 return EINVAL;
 1191 
 1192         if ((oid->oid_kind & CTLTYPE) == CTLTYPE_NODE)
 1193                 error = oid->oid_handler(oid, (int *)arg1 + indx, arg2 - indx,
 1194                     req);
 1195         else
 1196                 error = oid->oid_handler(oid, oid->oid_arg1, oid->oid_arg2,
 1197                     req);
 1198         return (error);
 1199 }
 1200 
 1201 /*
 1202  * MPALMOSTSAFE
 1203  */
 1204 int
 1205 sys___sysctl(struct sysctl_args *uap)
 1206 {
 1207         int error, i, name[CTL_MAXNAME];
 1208         size_t j;
 1209 
 1210         if (uap->namelen > CTL_MAXNAME || uap->namelen < 2)
 1211                 return (EINVAL);
 1212 
 1213         error = copyin(uap->name, &name, uap->namelen * sizeof(int));
 1214         if (error)
 1215                 return (error);
 1216 
 1217         error = userland_sysctl(name, uap->namelen,
 1218                 uap->old, uap->oldlenp, 0,
 1219                 uap->new, uap->newlen, &j);
 1220         if (error && error != ENOMEM)
 1221                 return (error);
 1222         if (uap->oldlenp) {
 1223                 i = copyout(&j, uap->oldlenp, sizeof(j));
 1224                 if (i)
 1225                         return (i);
 1226         }
 1227         return (error);
 1228 }
 1229 
 1230 /*
 1231  * This is used from various compatibility syscalls too.  That's why name
 1232  * must be in kernel space.
 1233  */
 1234 int
 1235 userland_sysctl(int *name, u_int namelen, void *old, size_t *oldlenp, int inkernel, void *new, size_t newlen, size_t *retval)
 1236 {
 1237         int error = 0;
 1238         struct sysctl_req req, req2;
 1239 
 1240         bzero(&req, sizeof req);
 1241 
 1242         if (oldlenp) {
 1243                 if (inkernel) {
 1244                         req.oldlen = *oldlenp;
 1245                 } else {
 1246                         error = copyin(oldlenp, &req.oldlen, sizeof(*oldlenp));
 1247                         if (error)
 1248                                 return (error);
 1249                 }
 1250         }
 1251 
 1252         if (old) {
 1253                 if (!useracc(old, req.oldlen, VM_PROT_WRITE))
 1254                         return (EFAULT);
 1255                 req.oldptr= old;
 1256         }
 1257 
 1258         if (new != NULL) {
 1259                 if (!useracc(new, newlen, VM_PROT_READ))
 1260                         return (EFAULT);
 1261                 req.newlen = newlen;
 1262                 req.newptr = new;
 1263         }
 1264 
 1265         req.oldfunc = sysctl_old_user;
 1266         req.newfunc = sysctl_new_user;
 1267 #if 0
 1268         req.lock = 1;
 1269 #endif
 1270         req.td = curthread;
 1271 
 1272         sysctl_lock(LK_SHARED);
 1273 
 1274         do {
 1275             req2 = req;
 1276             error = sysctl_root(0, name, namelen, &req2);
 1277         } while (error == EAGAIN);
 1278 
 1279         req = req2;
 1280 #if 0
 1281         if (req.lock == 2)
 1282                 vsunlock(req.oldptr, req.oldlen);
 1283 #endif
 1284 
 1285         sysctl_unlock();
 1286 
 1287         if (error && error != ENOMEM)
 1288                 return (error);
 1289 
 1290         if (retval) {
 1291                 if (req.oldptr && req.oldidx > req.oldlen)
 1292                         *retval = req.oldlen;
 1293                 else
 1294                         *retval = req.oldidx;
 1295         }
 1296         return (error);
 1297 }
 1298 
 1299 static void
 1300 sysctl_lock(int flag)
 1301 {
 1302         lockmgr(&sysctl_lkp, flag);
 1303 }
 1304 
 1305 static void
 1306 sysctl_unlock(void)
 1307 {
 1308         lockmgr(&sysctl_lkp, LK_RELEASE);
 1309 }
 1310 
 1311 static void
 1312 sysctl_ctx_lock(int flag)
 1313 {
 1314         lockmgr(&sysctl_ctx_lkp, flag);
 1315 }
 1316 
 1317 static void
 1318 sysctl_ctx_unlock(void)
 1319 {
 1320         lockmgr(&sysctl_ctx_lkp, LK_RELEASE);
 1321 }
 1322 
 1323 int
 1324 sysctl_int_range(SYSCTL_HANDLER_ARGS, int low, int high)
 1325 {
 1326         int error, value;
 1327 
 1328         value = *(int *)arg1;
 1329         error = sysctl_handle_int(oidp, &value, 0, req);
 1330         if (error || !req->newptr)
 1331                 return (error);
 1332         if (value < low || value > high)
 1333                 return (EINVAL);
 1334         *(int *)arg1 = value;
 1335         return (0);
 1336 }
Cache object: 7fda373f5d950c3cde6575f6a61fabdc
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FreeBSD/Linux Kernel Cross Reference sys/kern/kern_sysctl.c

FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_sysctl.c
