The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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

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    1 /*-
    2  * Copyright (c) 1997-2000 Doug Rabson
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  *
   14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   24  * SUCH DAMAGE.
   25  */
   26 
   27 #include <sys/cdefs.h>
   28 __FBSDID("$FreeBSD: releng/10.0/sys/kern/kern_linker.c 254813 2013-08-24 21:13:38Z markj $");
   29 
   30 #include "opt_ddb.h"
   31 #include "opt_kld.h"
   32 #include "opt_hwpmc_hooks.h"
   33 
   34 #include <sys/param.h>
   35 #include <sys/kernel.h>
   36 #include <sys/systm.h>
   37 #include <sys/malloc.h>
   38 #include <sys/sysproto.h>
   39 #include <sys/sysent.h>
   40 #include <sys/priv.h>
   41 #include <sys/proc.h>
   42 #include <sys/lock.h>
   43 #include <sys/mutex.h>
   44 #include <sys/sx.h>
   45 #include <sys/module.h>
   46 #include <sys/mount.h>
   47 #include <sys/linker.h>
   48 #include <sys/eventhandler.h>
   49 #include <sys/fcntl.h>
   50 #include <sys/jail.h>
   51 #include <sys/libkern.h>
   52 #include <sys/namei.h>
   53 #include <sys/vnode.h>
   54 #include <sys/syscallsubr.h>
   55 #include <sys/sysctl.h>
   56 
   57 #include <net/vnet.h>
   58 
   59 #include <security/mac/mac_framework.h>
   60 
   61 #include "linker_if.h"
   62 
   63 #ifdef HWPMC_HOOKS
   64 #include <sys/pmckern.h>
   65 #endif
   66 
   67 #ifdef KLD_DEBUG
   68 int kld_debug = 0;
   69 SYSCTL_INT(_debug, OID_AUTO, kld_debug, CTLFLAG_RW | CTLFLAG_TUN,
   70     &kld_debug, 0, "Set various levels of KLD debug");
   71 TUNABLE_INT("debug.kld_debug", &kld_debug);
   72 #endif
   73 
   74 /*
   75  * static char *linker_search_path(const char *name, struct mod_depend
   76  * *verinfo);
   77  */
   78 static const char       *linker_basename(const char *path);
   79 
   80 /*
   81  * Find a currently loaded file given its filename.
   82  */
   83 static linker_file_t linker_find_file_by_name(const char* _filename);
   84 
   85 /*
   86  * Find a currently loaded file given its file id.
   87  */
   88 static linker_file_t linker_find_file_by_id(int _fileid);
   89 
   90 /* Metadata from the static kernel */
   91 SET_DECLARE(modmetadata_set, struct mod_metadata);
   92 
   93 MALLOC_DEFINE(M_LINKER, "linker", "kernel linker");
   94 
   95 linker_file_t linker_kernel_file;
   96 
   97 static struct sx kld_sx;        /* kernel linker lock */
   98 
   99 /*
  100  * Load counter used by clients to determine if a linker file has been
  101  * re-loaded. This counter is incremented for each file load.
  102  */
  103 static int loadcnt;
  104 
  105 static linker_class_list_t classes;
  106 static linker_file_list_t linker_files;
  107 static int next_file_id = 1;
  108 static int linker_no_more_classes = 0;
  109 
  110 #define LINKER_GET_NEXT_FILE_ID(a) do {                                 \
  111         linker_file_t lftmp;                                            \
  112                                                                         \
  113         if (!cold)                                                      \
  114                 sx_assert(&kld_sx, SA_XLOCKED);                         \
  115 retry:                                                                  \
  116         TAILQ_FOREACH(lftmp, &linker_files, link) {                     \
  117                 if (next_file_id == lftmp->id) {                        \
  118                         next_file_id++;                                 \
  119                         goto retry;                                     \
  120                 }                                                       \
  121         }                                                               \
  122         (a) = next_file_id;                                             \
  123 } while(0)
  124 
  125 
  126 /* XXX wrong name; we're looking at version provision tags here, not modules */
  127 typedef TAILQ_HEAD(, modlist) modlisthead_t;
  128 struct modlist {
  129         TAILQ_ENTRY(modlist) link;      /* chain together all modules */
  130         linker_file_t   container;
  131         const char      *name;
  132         int             version;
  133 };
  134 typedef struct modlist *modlist_t;
  135 static modlisthead_t found_modules;
  136 
  137 static int      linker_file_add_dependency(linker_file_t file,
  138                     linker_file_t dep);
  139 static caddr_t  linker_file_lookup_symbol_internal(linker_file_t file,
  140                     const char* name, int deps);
  141 static int      linker_load_module(const char *kldname,
  142                     const char *modname, struct linker_file *parent,
  143                     struct mod_depend *verinfo, struct linker_file **lfpp);
  144 static modlist_t modlist_lookup2(const char *name, struct mod_depend *verinfo);
  145 
  146 static void
  147 linker_init(void *arg)
  148 {
  149 
  150         sx_init(&kld_sx, "kernel linker");
  151         TAILQ_INIT(&classes);
  152         TAILQ_INIT(&linker_files);
  153 }
  154 
  155 SYSINIT(linker, SI_SUB_KLD, SI_ORDER_FIRST, linker_init, 0);
  156 
  157 static void
  158 linker_stop_class_add(void *arg)
  159 {
  160 
  161         linker_no_more_classes = 1;
  162 }
  163 
  164 SYSINIT(linker_class, SI_SUB_KLD, SI_ORDER_ANY, linker_stop_class_add, NULL);
  165 
  166 int
  167 linker_add_class(linker_class_t lc)
  168 {
  169 
  170         /*
  171          * We disallow any class registration past SI_ORDER_ANY
  172          * of SI_SUB_KLD.  We bump the reference count to keep the
  173          * ops from being freed.
  174          */
  175         if (linker_no_more_classes == 1)
  176                 return (EPERM);
  177         kobj_class_compile((kobj_class_t) lc);
  178         ((kobj_class_t)lc)->refs++;     /* XXX: kobj_mtx */
  179         TAILQ_INSERT_TAIL(&classes, lc, link);
  180         return (0);
  181 }
  182 
  183 static void
  184 linker_file_sysinit(linker_file_t lf)
  185 {
  186         struct sysinit **start, **stop, **sipp, **xipp, *save;
  187 
  188         KLD_DPF(FILE, ("linker_file_sysinit: calling SYSINITs for %s\n",
  189             lf->filename));
  190 
  191         sx_assert(&kld_sx, SA_XLOCKED);
  192 
  193         if (linker_file_lookup_set(lf, "sysinit_set", &start, &stop, NULL) != 0)
  194                 return;
  195         /*
  196          * Perform a bubble sort of the system initialization objects by
  197          * their subsystem (primary key) and order (secondary key).
  198          *
  199          * Since some things care about execution order, this is the operation
  200          * which ensures continued function.
  201          */
  202         for (sipp = start; sipp < stop; sipp++) {
  203                 for (xipp = sipp + 1; xipp < stop; xipp++) {
  204                         if ((*sipp)->subsystem < (*xipp)->subsystem ||
  205                             ((*sipp)->subsystem == (*xipp)->subsystem &&
  206                             (*sipp)->order <= (*xipp)->order))
  207                                 continue;       /* skip */
  208                         save = *sipp;
  209                         *sipp = *xipp;
  210                         *xipp = save;
  211                 }
  212         }
  213 
  214         /*
  215          * Traverse the (now) ordered list of system initialization tasks.
  216          * Perform each task, and continue on to the next task.
  217          */
  218         sx_xunlock(&kld_sx);
  219         mtx_lock(&Giant);
  220         for (sipp = start; sipp < stop; sipp++) {
  221                 if ((*sipp)->subsystem == SI_SUB_DUMMY)
  222                         continue;       /* skip dummy task(s) */
  223 
  224                 /* Call function */
  225                 (*((*sipp)->func)) ((*sipp)->udata);
  226         }
  227         mtx_unlock(&Giant);
  228         sx_xlock(&kld_sx);
  229 }
  230 
  231 static void
  232 linker_file_sysuninit(linker_file_t lf)
  233 {
  234         struct sysinit **start, **stop, **sipp, **xipp, *save;
  235 
  236         KLD_DPF(FILE, ("linker_file_sysuninit: calling SYSUNINITs for %s\n",
  237             lf->filename));
  238 
  239         sx_assert(&kld_sx, SA_XLOCKED);
  240 
  241         if (linker_file_lookup_set(lf, "sysuninit_set", &start, &stop,
  242             NULL) != 0)
  243                 return;
  244 
  245         /*
  246          * Perform a reverse bubble sort of the system initialization objects
  247          * by their subsystem (primary key) and order (secondary key).
  248          *
  249          * Since some things care about execution order, this is the operation
  250          * which ensures continued function.
  251          */
  252         for (sipp = start; sipp < stop; sipp++) {
  253                 for (xipp = sipp + 1; xipp < stop; xipp++) {
  254                         if ((*sipp)->subsystem > (*xipp)->subsystem ||
  255                             ((*sipp)->subsystem == (*xipp)->subsystem &&
  256                             (*sipp)->order >= (*xipp)->order))
  257                                 continue;       /* skip */
  258                         save = *sipp;
  259                         *sipp = *xipp;
  260                         *xipp = save;
  261                 }
  262         }
  263 
  264         /*
  265          * Traverse the (now) ordered list of system initialization tasks.
  266          * Perform each task, and continue on to the next task.
  267          */
  268         sx_xunlock(&kld_sx);
  269         mtx_lock(&Giant);
  270         for (sipp = start; sipp < stop; sipp++) {
  271                 if ((*sipp)->subsystem == SI_SUB_DUMMY)
  272                         continue;       /* skip dummy task(s) */
  273 
  274                 /* Call function */
  275                 (*((*sipp)->func)) ((*sipp)->udata);
  276         }
  277         mtx_unlock(&Giant);
  278         sx_xlock(&kld_sx);
  279 }
  280 
  281 static void
  282 linker_file_register_sysctls(linker_file_t lf)
  283 {
  284         struct sysctl_oid **start, **stop, **oidp;
  285 
  286         KLD_DPF(FILE,
  287             ("linker_file_register_sysctls: registering SYSCTLs for %s\n",
  288             lf->filename));
  289 
  290         sx_assert(&kld_sx, SA_XLOCKED);
  291 
  292         if (linker_file_lookup_set(lf, "sysctl_set", &start, &stop, NULL) != 0)
  293                 return;
  294 
  295         sx_xunlock(&kld_sx);
  296         sysctl_lock();
  297         for (oidp = start; oidp < stop; oidp++)
  298                 sysctl_register_oid(*oidp);
  299         sysctl_unlock();
  300         sx_xlock(&kld_sx);
  301 }
  302 
  303 static void
  304 linker_file_unregister_sysctls(linker_file_t lf)
  305 {
  306         struct sysctl_oid **start, **stop, **oidp;
  307 
  308         KLD_DPF(FILE, ("linker_file_unregister_sysctls: unregistering SYSCTLs"
  309             " for %s\n", lf->filename));
  310 
  311         sx_assert(&kld_sx, SA_XLOCKED);
  312 
  313         if (linker_file_lookup_set(lf, "sysctl_set", &start, &stop, NULL) != 0)
  314                 return;
  315 
  316         sx_xunlock(&kld_sx);
  317         sysctl_lock();
  318         for (oidp = start; oidp < stop; oidp++)
  319                 sysctl_unregister_oid(*oidp);
  320         sysctl_unlock();
  321         sx_xlock(&kld_sx);
  322 }
  323 
  324 static int
  325 linker_file_register_modules(linker_file_t lf)
  326 {
  327         struct mod_metadata **start, **stop, **mdp;
  328         const moduledata_t *moddata;
  329         int first_error, error;
  330 
  331         KLD_DPF(FILE, ("linker_file_register_modules: registering modules"
  332             " in %s\n", lf->filename));
  333 
  334         sx_assert(&kld_sx, SA_XLOCKED);
  335 
  336         if (linker_file_lookup_set(lf, "modmetadata_set", &start,
  337             &stop, NULL) != 0) {
  338                 /*
  339                  * This fallback should be unnecessary, but if we get booted
  340                  * from boot2 instead of loader and we are missing our
  341                  * metadata then we have to try the best we can.
  342                  */
  343                 if (lf == linker_kernel_file) {
  344                         start = SET_BEGIN(modmetadata_set);
  345                         stop = SET_LIMIT(modmetadata_set);
  346                 } else
  347                         return (0);
  348         }
  349         first_error = 0;
  350         for (mdp = start; mdp < stop; mdp++) {
  351                 if ((*mdp)->md_type != MDT_MODULE)
  352                         continue;
  353                 moddata = (*mdp)->md_data;
  354                 KLD_DPF(FILE, ("Registering module %s in %s\n",
  355                     moddata->name, lf->filename));
  356                 error = module_register(moddata, lf);
  357                 if (error) {
  358                         printf("Module %s failed to register: %d\n",
  359                             moddata->name, error);
  360                         if (first_error == 0)
  361                                 first_error = error;
  362                 }
  363         }
  364         return (first_error);
  365 }
  366 
  367 static void
  368 linker_init_kernel_modules(void)
  369 {
  370 
  371         sx_xlock(&kld_sx);
  372         linker_file_register_modules(linker_kernel_file);
  373         sx_xunlock(&kld_sx);
  374 }
  375 
  376 SYSINIT(linker_kernel, SI_SUB_KLD, SI_ORDER_ANY, linker_init_kernel_modules,
  377     0);
  378 
  379 static int
  380 linker_load_file(const char *filename, linker_file_t *result)
  381 {
  382         linker_class_t lc;
  383         linker_file_t lf;
  384         int foundfile, error, modules;
  385 
  386         /* Refuse to load modules if securelevel raised */
  387         if (prison0.pr_securelevel > 0)
  388                 return (EPERM);
  389 
  390         sx_assert(&kld_sx, SA_XLOCKED);
  391         lf = linker_find_file_by_name(filename);
  392         if (lf) {
  393                 KLD_DPF(FILE, ("linker_load_file: file %s is already loaded,"
  394                     " incrementing refs\n", filename));
  395                 *result = lf;
  396                 lf->refs++;
  397                 return (0);
  398         }
  399         foundfile = 0;
  400         error = 0;
  401 
  402         /*
  403          * We do not need to protect (lock) classes here because there is
  404          * no class registration past startup (SI_SUB_KLD, SI_ORDER_ANY)
  405          * and there is no class deregistration mechanism at this time.
  406          */
  407         TAILQ_FOREACH(lc, &classes, link) {
  408                 KLD_DPF(FILE, ("linker_load_file: trying to load %s\n",
  409                     filename));
  410                 error = LINKER_LOAD_FILE(lc, filename, &lf);
  411                 /*
  412                  * If we got something other than ENOENT, then it exists but
  413                  * we cannot load it for some other reason.
  414                  */
  415                 if (error != ENOENT)
  416                         foundfile = 1;
  417                 if (lf) {
  418                         error = linker_file_register_modules(lf);
  419                         if (error == EEXIST) {
  420                                 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
  421                                 return (error);
  422                         }
  423                         modules = !TAILQ_EMPTY(&lf->modules);
  424                         linker_file_register_sysctls(lf);
  425                         linker_file_sysinit(lf);
  426                         lf->flags |= LINKER_FILE_LINKED;
  427 
  428                         /*
  429                          * If all of the modules in this file failed
  430                          * to load, unload the file and return an
  431                          * error of ENOEXEC.
  432                          */
  433                         if (modules && TAILQ_EMPTY(&lf->modules)) {
  434                                 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
  435                                 return (ENOEXEC);
  436                         }
  437                         *result = lf;
  438                         return (0);
  439                 }
  440         }
  441         /*
  442          * Less than ideal, but tells the user whether it failed to load or
  443          * the module was not found.
  444          */
  445         if (foundfile) {
  446 
  447                 /*
  448                  * If the file type has not been recognized by the last try
  449                  * printout a message before to fail.
  450                  */
  451                 if (error == ENOSYS)
  452                         printf("linker_load_file: Unsupported file type\n");
  453 
  454                 /*
  455                  * Format not recognized or otherwise unloadable.
  456                  * When loading a module that is statically built into
  457                  * the kernel EEXIST percolates back up as the return
  458                  * value.  Preserve this so that apps like sysinstall
  459                  * can recognize this special case and not post bogus
  460                  * dialog boxes.
  461                  */
  462                 if (error != EEXIST)
  463                         error = ENOEXEC;
  464         } else
  465                 error = ENOENT;         /* Nothing found */
  466         return (error);
  467 }
  468 
  469 int
  470 linker_reference_module(const char *modname, struct mod_depend *verinfo,
  471     linker_file_t *result)
  472 {
  473         modlist_t mod;
  474         int error;
  475 
  476         sx_xlock(&kld_sx);
  477         if ((mod = modlist_lookup2(modname, verinfo)) != NULL) {
  478                 *result = mod->container;
  479                 (*result)->refs++;
  480                 sx_xunlock(&kld_sx);
  481                 return (0);
  482         }
  483 
  484         error = linker_load_module(NULL, modname, NULL, verinfo, result);
  485         sx_xunlock(&kld_sx);
  486         return (error);
  487 }
  488 
  489 int
  490 linker_release_module(const char *modname, struct mod_depend *verinfo,
  491     linker_file_t lf)
  492 {
  493         modlist_t mod;
  494         int error;
  495 
  496         sx_xlock(&kld_sx);
  497         if (lf == NULL) {
  498                 KASSERT(modname != NULL,
  499                     ("linker_release_module: no file or name"));
  500                 mod = modlist_lookup2(modname, verinfo);
  501                 if (mod == NULL) {
  502                         sx_xunlock(&kld_sx);
  503                         return (ESRCH);
  504                 }
  505                 lf = mod->container;
  506         } else
  507                 KASSERT(modname == NULL && verinfo == NULL,
  508                     ("linker_release_module: both file and name"));
  509         error = linker_file_unload(lf, LINKER_UNLOAD_NORMAL);
  510         sx_xunlock(&kld_sx);
  511         return (error);
  512 }
  513 
  514 static linker_file_t
  515 linker_find_file_by_name(const char *filename)
  516 {
  517         linker_file_t lf;
  518         char *koname;
  519 
  520         koname = malloc(strlen(filename) + 4, M_LINKER, M_WAITOK);
  521         sprintf(koname, "%s.ko", filename);
  522 
  523         sx_assert(&kld_sx, SA_XLOCKED);
  524         TAILQ_FOREACH(lf, &linker_files, link) {
  525                 if (strcmp(lf->filename, koname) == 0)
  526                         break;
  527                 if (strcmp(lf->filename, filename) == 0)
  528                         break;
  529         }
  530         free(koname, M_LINKER);
  531         return (lf);
  532 }
  533 
  534 static linker_file_t
  535 linker_find_file_by_id(int fileid)
  536 {
  537         linker_file_t lf;
  538 
  539         sx_assert(&kld_sx, SA_XLOCKED);
  540         TAILQ_FOREACH(lf, &linker_files, link)
  541                 if (lf->id == fileid && lf->flags & LINKER_FILE_LINKED)
  542                         break;
  543         return (lf);
  544 }
  545 
  546 int
  547 linker_file_foreach(linker_predicate_t *predicate, void *context)
  548 {
  549         linker_file_t lf;
  550         int retval = 0;
  551 
  552         sx_xlock(&kld_sx);
  553         TAILQ_FOREACH(lf, &linker_files, link) {
  554                 retval = predicate(lf, context);
  555                 if (retval != 0)
  556                         break;
  557         }
  558         sx_xunlock(&kld_sx);
  559         return (retval);
  560 }
  561 
  562 linker_file_t
  563 linker_make_file(const char *pathname, linker_class_t lc)
  564 {
  565         linker_file_t lf;
  566         const char *filename;
  567 
  568         if (!cold)
  569                 sx_assert(&kld_sx, SA_XLOCKED);
  570         filename = linker_basename(pathname);
  571 
  572         KLD_DPF(FILE, ("linker_make_file: new file, filename='%s' for pathname='%s'\n", filename, pathname));
  573         lf = (linker_file_t)kobj_create((kobj_class_t)lc, M_LINKER, M_WAITOK);
  574         if (lf == NULL)
  575                 return (NULL);
  576         lf->refs = 1;
  577         lf->userrefs = 0;
  578         lf->flags = 0;
  579         lf->filename = strdup(filename, M_LINKER);
  580         lf->pathname = strdup(pathname, M_LINKER);
  581         LINKER_GET_NEXT_FILE_ID(lf->id);
  582         lf->ndeps = 0;
  583         lf->deps = NULL;
  584         lf->loadcnt = ++loadcnt;
  585         STAILQ_INIT(&lf->common);
  586         TAILQ_INIT(&lf->modules);
  587         TAILQ_INSERT_TAIL(&linker_files, lf, link);
  588         return (lf);
  589 }
  590 
  591 int
  592 linker_file_unload(linker_file_t file, int flags)
  593 {
  594         module_t mod, next;
  595         modlist_t ml, nextml;
  596         struct common_symbol *cp;
  597         int error, i;
  598 
  599         /* Refuse to unload modules if securelevel raised. */
  600         if (prison0.pr_securelevel > 0)
  601                 return (EPERM);
  602 
  603         sx_assert(&kld_sx, SA_XLOCKED);
  604         KLD_DPF(FILE, ("linker_file_unload: lf->refs=%d\n", file->refs));
  605 
  606         /* Easy case of just dropping a reference. */
  607         if (file->refs > 1) {
  608                 file->refs--;
  609                 return (0);
  610         }
  611 
  612         KLD_DPF(FILE, ("linker_file_unload: file is unloading,"
  613             " informing modules\n"));
  614 
  615         /*
  616          * Quiesce all the modules to give them a chance to veto the unload.
  617          */
  618         MOD_SLOCK;
  619         for (mod = TAILQ_FIRST(&file->modules); mod;
  620              mod = module_getfnext(mod)) {
  621 
  622                 error = module_quiesce(mod);
  623                 if (error != 0 && flags != LINKER_UNLOAD_FORCE) {
  624                         KLD_DPF(FILE, ("linker_file_unload: module %s"
  625                             " vetoed unload\n", module_getname(mod)));
  626                         /*
  627                          * XXX: Do we need to tell all the quiesced modules
  628                          * that they can resume work now via a new module
  629                          * event?
  630                          */
  631                         MOD_SUNLOCK;
  632                         return (error);
  633                 }
  634         }
  635         MOD_SUNLOCK;
  636 
  637         /*
  638          * Inform any modules associated with this file that they are
  639          * being unloaded.
  640          */
  641         MOD_XLOCK;
  642         for (mod = TAILQ_FIRST(&file->modules); mod; mod = next) {
  643                 next = module_getfnext(mod);
  644                 MOD_XUNLOCK;
  645 
  646                 /*
  647                  * Give the module a chance to veto the unload.
  648                  */
  649                 if ((error = module_unload(mod)) != 0) {
  650 #ifdef KLD_DEBUG
  651                         MOD_SLOCK;
  652                         KLD_DPF(FILE, ("linker_file_unload: module %s"
  653                             " failed unload\n", module_getname(mod)));
  654                         MOD_SUNLOCK;
  655 #endif
  656                         return (error);
  657                 }
  658                 MOD_XLOCK;
  659                 module_release(mod);
  660         }
  661         MOD_XUNLOCK;
  662 
  663         TAILQ_FOREACH_SAFE(ml, &found_modules, link, nextml) {
  664                 if (ml->container == file) {
  665                         TAILQ_REMOVE(&found_modules, ml, link);
  666                         free(ml, M_LINKER);
  667                 }
  668         }
  669 
  670         /*
  671          * Don't try to run SYSUNINITs if we are unloaded due to a
  672          * link error.
  673          */
  674         if (file->flags & LINKER_FILE_LINKED) {
  675                 file->flags &= ~LINKER_FILE_LINKED;
  676                 linker_file_sysuninit(file);
  677                 linker_file_unregister_sysctls(file);
  678         }
  679         TAILQ_REMOVE(&linker_files, file, link);
  680 
  681         if (file->deps) {
  682                 for (i = 0; i < file->ndeps; i++)
  683                         linker_file_unload(file->deps[i], flags);
  684                 free(file->deps, M_LINKER);
  685                 file->deps = NULL;
  686         }
  687         while ((cp = STAILQ_FIRST(&file->common)) != NULL) {
  688                 STAILQ_REMOVE_HEAD(&file->common, link);
  689                 free(cp, M_LINKER);
  690         }
  691 
  692         LINKER_UNLOAD(file);
  693         if (file->filename) {
  694                 free(file->filename, M_LINKER);
  695                 file->filename = NULL;
  696         }
  697         if (file->pathname) {
  698                 free(file->pathname, M_LINKER);
  699                 file->pathname = NULL;
  700         }
  701         kobj_delete((kobj_t) file, M_LINKER);
  702         return (0);
  703 }
  704 
  705 int
  706 linker_ctf_get(linker_file_t file, linker_ctf_t *lc)
  707 {
  708         return (LINKER_CTF_GET(file, lc));
  709 }
  710 
  711 static int
  712 linker_file_add_dependency(linker_file_t file, linker_file_t dep)
  713 {
  714         linker_file_t *newdeps;
  715 
  716         sx_assert(&kld_sx, SA_XLOCKED);
  717         newdeps = malloc((file->ndeps + 1) * sizeof(linker_file_t *),
  718             M_LINKER, M_WAITOK | M_ZERO);
  719         if (newdeps == NULL)
  720                 return (ENOMEM);
  721 
  722         if (file->deps) {
  723                 bcopy(file->deps, newdeps,
  724                     file->ndeps * sizeof(linker_file_t *));
  725                 free(file->deps, M_LINKER);
  726         }
  727         file->deps = newdeps;
  728         file->deps[file->ndeps] = dep;
  729         file->ndeps++;
  730         KLD_DPF(FILE, ("linker_file_add_dependency:"
  731             " adding %s as dependency for %s\n", 
  732             dep->filename, file->filename));
  733         return (0);
  734 }
  735 
  736 /*
  737  * Locate a linker set and its contents.  This is a helper function to avoid
  738  * linker_if.h exposure elsewhere.  Note: firstp and lastp are really void **.
  739  * This function is used in this file so we can avoid having lots of (void **)
  740  * casts.
  741  */
  742 int
  743 linker_file_lookup_set(linker_file_t file, const char *name,
  744     void *firstp, void *lastp, int *countp)
  745 {
  746 
  747         sx_assert(&kld_sx, SA_LOCKED);
  748         return (LINKER_LOOKUP_SET(file, name, firstp, lastp, countp));
  749 }
  750 
  751 /*
  752  * List all functions in a file.
  753  */
  754 int
  755 linker_file_function_listall(linker_file_t lf,
  756     linker_function_nameval_callback_t callback_func, void *arg)
  757 {
  758         return (LINKER_EACH_FUNCTION_NAMEVAL(lf, callback_func, arg));
  759 }
  760 
  761 caddr_t
  762 linker_file_lookup_symbol(linker_file_t file, const char *name, int deps)
  763 {
  764         caddr_t sym;
  765         int locked;
  766 
  767         locked = sx_xlocked(&kld_sx);
  768         if (!locked)
  769                 sx_xlock(&kld_sx);
  770         sym = linker_file_lookup_symbol_internal(file, name, deps);
  771         if (!locked)
  772                 sx_xunlock(&kld_sx);
  773         return (sym);
  774 }
  775 
  776 static caddr_t
  777 linker_file_lookup_symbol_internal(linker_file_t file, const char *name,
  778     int deps)
  779 {
  780         c_linker_sym_t sym;
  781         linker_symval_t symval;
  782         caddr_t address;
  783         size_t common_size = 0;
  784         int i;
  785 
  786         sx_assert(&kld_sx, SA_XLOCKED);
  787         KLD_DPF(SYM, ("linker_file_lookup_symbol: file=%p, name=%s, deps=%d\n",
  788             file, name, deps));
  789 
  790         if (LINKER_LOOKUP_SYMBOL(file, name, &sym) == 0) {
  791                 LINKER_SYMBOL_VALUES(file, sym, &symval);
  792                 if (symval.value == 0)
  793                         /*
  794                          * For commons, first look them up in the
  795                          * dependencies and only allocate space if not found
  796                          * there.
  797                          */
  798                         common_size = symval.size;
  799                 else {
  800                         KLD_DPF(SYM, ("linker_file_lookup_symbol: symbol"
  801                             ".value=%p\n", symval.value));
  802                         return (symval.value);
  803                 }
  804         }
  805         if (deps) {
  806                 for (i = 0; i < file->ndeps; i++) {
  807                         address = linker_file_lookup_symbol_internal(
  808                             file->deps[i], name, 0);
  809                         if (address) {
  810                                 KLD_DPF(SYM, ("linker_file_lookup_symbol:"
  811                                     " deps value=%p\n", address));
  812                                 return (address);
  813                         }
  814                 }
  815         }
  816         if (common_size > 0) {
  817                 /*
  818                  * This is a common symbol which was not found in the
  819                  * dependencies.  We maintain a simple common symbol table in
  820                  * the file object.
  821                  */
  822                 struct common_symbol *cp;
  823 
  824                 STAILQ_FOREACH(cp, &file->common, link) {
  825                         if (strcmp(cp->name, name) == 0) {
  826                                 KLD_DPF(SYM, ("linker_file_lookup_symbol:"
  827                                     " old common value=%p\n", cp->address));
  828                                 return (cp->address);
  829                         }
  830                 }
  831                 /*
  832                  * Round the symbol size up to align.
  833                  */
  834                 common_size = (common_size + sizeof(int) - 1) & -sizeof(int);
  835                 cp = malloc(sizeof(struct common_symbol)
  836                     + common_size + strlen(name) + 1, M_LINKER,
  837                     M_WAITOK | M_ZERO);
  838                 cp->address = (caddr_t)(cp + 1);
  839                 cp->name = cp->address + common_size;
  840                 strcpy(cp->name, name);
  841                 bzero(cp->address, common_size);
  842                 STAILQ_INSERT_TAIL(&file->common, cp, link);
  843 
  844                 KLD_DPF(SYM, ("linker_file_lookup_symbol: new common"
  845                     " value=%p\n", cp->address));
  846                 return (cp->address);
  847         }
  848         KLD_DPF(SYM, ("linker_file_lookup_symbol: fail\n"));
  849         return (0);
  850 }
  851 
  852 /*
  853  * Both DDB and stack(9) rely on the kernel linker to provide forward and
  854  * backward lookup of symbols.  However, DDB and sometimes stack(9) need to
  855  * do this in a lockfree manner.  We provide a set of internal helper
  856  * routines to perform these operations without locks, and then wrappers that
  857  * optionally lock.
  858  *
  859  * linker_debug_lookup() is ifdef DDB as currently it's only used by DDB.
  860  */
  861 #ifdef DDB
  862 static int
  863 linker_debug_lookup(const char *symstr, c_linker_sym_t *sym)
  864 {
  865         linker_file_t lf;
  866 
  867         TAILQ_FOREACH(lf, &linker_files, link) {
  868                 if (LINKER_LOOKUP_SYMBOL(lf, symstr, sym) == 0)
  869                         return (0);
  870         }
  871         return (ENOENT);
  872 }
  873 #endif
  874 
  875 static int
  876 linker_debug_search_symbol(caddr_t value, c_linker_sym_t *sym, long *diffp)
  877 {
  878         linker_file_t lf;
  879         c_linker_sym_t best, es;
  880         u_long diff, bestdiff, off;
  881 
  882         best = 0;
  883         off = (uintptr_t)value;
  884         bestdiff = off;
  885         TAILQ_FOREACH(lf, &linker_files, link) {
  886                 if (LINKER_SEARCH_SYMBOL(lf, value, &es, &diff) != 0)
  887                         continue;
  888                 if (es != 0 && diff < bestdiff) {
  889                         best = es;
  890                         bestdiff = diff;
  891                 }
  892                 if (bestdiff == 0)
  893                         break;
  894         }
  895         if (best) {
  896                 *sym = best;
  897                 *diffp = bestdiff;
  898                 return (0);
  899         } else {
  900                 *sym = 0;
  901                 *diffp = off;
  902                 return (ENOENT);
  903         }
  904 }
  905 
  906 static int
  907 linker_debug_symbol_values(c_linker_sym_t sym, linker_symval_t *symval)
  908 {
  909         linker_file_t lf;
  910 
  911         TAILQ_FOREACH(lf, &linker_files, link) {
  912                 if (LINKER_SYMBOL_VALUES(lf, sym, symval) == 0)
  913                         return (0);
  914         }
  915         return (ENOENT);
  916 }
  917 
  918 static int
  919 linker_debug_search_symbol_name(caddr_t value, char *buf, u_int buflen,
  920     long *offset)
  921 {
  922         linker_symval_t symval;
  923         c_linker_sym_t sym;
  924         int error;
  925 
  926         *offset = 0;
  927         error = linker_debug_search_symbol(value, &sym, offset);
  928         if (error)
  929                 return (error);
  930         error = linker_debug_symbol_values(sym, &symval);
  931         if (error)
  932                 return (error);
  933         strlcpy(buf, symval.name, buflen);
  934         return (0);
  935 }
  936 
  937 /*
  938  * DDB Helpers.  DDB has to look across multiple files with their own symbol
  939  * tables and string tables.
  940  *
  941  * Note that we do not obey list locking protocols here.  We really don't need
  942  * DDB to hang because somebody's got the lock held.  We'll take the chance
  943  * that the files list is inconsistant instead.
  944  */
  945 #ifdef DDB
  946 int
  947 linker_ddb_lookup(const char *symstr, c_linker_sym_t *sym)
  948 {
  949 
  950         return (linker_debug_lookup(symstr, sym));
  951 }
  952 #endif
  953 
  954 int
  955 linker_ddb_search_symbol(caddr_t value, c_linker_sym_t *sym, long *diffp)
  956 {
  957 
  958         return (linker_debug_search_symbol(value, sym, diffp));
  959 }
  960 
  961 int
  962 linker_ddb_symbol_values(c_linker_sym_t sym, linker_symval_t *symval)
  963 {
  964 
  965         return (linker_debug_symbol_values(sym, symval));
  966 }
  967 
  968 int
  969 linker_ddb_search_symbol_name(caddr_t value, char *buf, u_int buflen,
  970     long *offset)
  971 {
  972 
  973         return (linker_debug_search_symbol_name(value, buf, buflen, offset));
  974 }
  975 
  976 /*
  977  * stack(9) helper for non-debugging environemnts.  Unlike DDB helpers, we do
  978  * obey locking protocols, and offer a significantly less complex interface.
  979  */
  980 int
  981 linker_search_symbol_name(caddr_t value, char *buf, u_int buflen,
  982     long *offset)
  983 {
  984         int error;
  985 
  986         sx_xlock(&kld_sx);
  987         error = linker_debug_search_symbol_name(value, buf, buflen, offset);
  988         sx_xunlock(&kld_sx);
  989         return (error);
  990 }
  991 
  992 /*
  993  * Syscalls.
  994  */
  995 int
  996 kern_kldload(struct thread *td, const char *file, int *fileid)
  997 {
  998         const char *kldname, *modname;
  999         linker_file_t lf;
 1000         int error;
 1001 
 1002         if ((error = securelevel_gt(td->td_ucred, 0)) != 0)
 1003                 return (error);
 1004 
 1005         if ((error = priv_check(td, PRIV_KLD_LOAD)) != 0)
 1006                 return (error);
 1007 
 1008         /*
 1009          * It is possible that kldloaded module will attach a new ifnet,
 1010          * so vnet context must be set when this ocurs.
 1011          */
 1012         CURVNET_SET(TD_TO_VNET(td));
 1013 
 1014         /*
 1015          * If file does not contain a qualified name or any dot in it
 1016          * (kldname.ko, or kldname.ver.ko) treat it as an interface
 1017          * name.
 1018          */
 1019         if (strchr(file, '/') || strchr(file, '.')) {
 1020                 kldname = file;
 1021                 modname = NULL;
 1022         } else {
 1023                 kldname = NULL;
 1024                 modname = file;
 1025         }
 1026 
 1027         sx_xlock(&kld_sx);
 1028         error = linker_load_module(kldname, modname, NULL, NULL, &lf);
 1029         if (error) {
 1030                 sx_xunlock(&kld_sx);
 1031                 goto done;
 1032         }
 1033         lf->userrefs++;
 1034         if (fileid != NULL)
 1035                 *fileid = lf->id;
 1036 
 1037         sx_downgrade(&kld_sx);
 1038         EVENTHANDLER_INVOKE(kld_load, lf);
 1039         sx_sunlock(&kld_sx);
 1040 
 1041 done:
 1042         CURVNET_RESTORE();
 1043         return (error);
 1044 }
 1045 
 1046 int
 1047 sys_kldload(struct thread *td, struct kldload_args *uap)
 1048 {
 1049         char *pathname = NULL;
 1050         int error, fileid;
 1051 
 1052         td->td_retval[0] = -1;
 1053 
 1054         pathname = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
 1055         error = copyinstr(uap->file, pathname, MAXPATHLEN, NULL);
 1056         if (error == 0) {
 1057                 error = kern_kldload(td, pathname, &fileid);
 1058                 if (error == 0)
 1059                         td->td_retval[0] = fileid;
 1060         }
 1061         free(pathname, M_TEMP);
 1062         return (error);
 1063 }
 1064 
 1065 int
 1066 kern_kldunload(struct thread *td, int fileid, int flags)
 1067 {
 1068         linker_file_t lf;
 1069         char *filename = NULL;
 1070         caddr_t address;
 1071         size_t size;
 1072         int error = 0;
 1073 
 1074         if ((error = securelevel_gt(td->td_ucred, 0)) != 0)
 1075                 return (error);
 1076 
 1077         if ((error = priv_check(td, PRIV_KLD_UNLOAD)) != 0)
 1078                 return (error);
 1079 
 1080         CURVNET_SET(TD_TO_VNET(td));
 1081         sx_xlock(&kld_sx);
 1082         lf = linker_find_file_by_id(fileid);
 1083         if (lf) {
 1084                 KLD_DPF(FILE, ("kldunload: lf->userrefs=%d\n", lf->userrefs));
 1085 
 1086                 EVENTHANDLER_INVOKE(kld_unload_try, lf, &error);
 1087                 if (error != 0)
 1088                         error = EBUSY;
 1089                 else if (lf->userrefs == 0) {
 1090                         /*
 1091                          * XXX: maybe LINKER_UNLOAD_FORCE should override ?
 1092                          */
 1093                         printf("kldunload: attempt to unload file that was"
 1094                             " loaded by the kernel\n");
 1095                         error = EBUSY;
 1096                 } else {
 1097                         /* Save data needed for the kld_unload callbacks. */
 1098                         filename = strdup(lf->filename, M_TEMP);
 1099                         address = lf->address;
 1100                         size = lf->size;
 1101 
 1102                         lf->userrefs--;
 1103                         error = linker_file_unload(lf, flags);
 1104                         if (error)
 1105                                 lf->userrefs++;
 1106                 }
 1107         } else
 1108                 error = ENOENT;
 1109 
 1110         if (error == 0) {
 1111                 sx_downgrade(&kld_sx);
 1112                 EVENTHANDLER_INVOKE(kld_unload, filename, address, size);
 1113                 sx_sunlock(&kld_sx);
 1114         } else
 1115                 sx_xunlock(&kld_sx);
 1116         free(filename, M_TEMP);
 1117 
 1118         CURVNET_RESTORE();
 1119         return (error);
 1120 }
 1121 
 1122 int
 1123 sys_kldunload(struct thread *td, struct kldunload_args *uap)
 1124 {
 1125 
 1126         return (kern_kldunload(td, uap->fileid, LINKER_UNLOAD_NORMAL));
 1127 }
 1128 
 1129 int
 1130 sys_kldunloadf(struct thread *td, struct kldunloadf_args *uap)
 1131 {
 1132 
 1133         if (uap->flags != LINKER_UNLOAD_NORMAL &&
 1134             uap->flags != LINKER_UNLOAD_FORCE)
 1135                 return (EINVAL);
 1136         return (kern_kldunload(td, uap->fileid, uap->flags));
 1137 }
 1138 
 1139 int
 1140 sys_kldfind(struct thread *td, struct kldfind_args *uap)
 1141 {
 1142         char *pathname;
 1143         const char *filename;
 1144         linker_file_t lf;
 1145         int error;
 1146 
 1147 #ifdef MAC
 1148         error = mac_kld_check_stat(td->td_ucred);
 1149         if (error)
 1150                 return (error);
 1151 #endif
 1152 
 1153         td->td_retval[0] = -1;
 1154 
 1155         pathname = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
 1156         if ((error = copyinstr(uap->file, pathname, MAXPATHLEN, NULL)) != 0)
 1157                 goto out;
 1158 
 1159         filename = linker_basename(pathname);
 1160         sx_xlock(&kld_sx);
 1161         lf = linker_find_file_by_name(filename);
 1162         if (lf)
 1163                 td->td_retval[0] = lf->id;
 1164         else
 1165                 error = ENOENT;
 1166         sx_xunlock(&kld_sx);
 1167 out:
 1168         free(pathname, M_TEMP);
 1169         return (error);
 1170 }
 1171 
 1172 int
 1173 sys_kldnext(struct thread *td, struct kldnext_args *uap)
 1174 {
 1175         linker_file_t lf;
 1176         int error = 0;
 1177 
 1178 #ifdef MAC
 1179         error = mac_kld_check_stat(td->td_ucred);
 1180         if (error)
 1181                 return (error);
 1182 #endif
 1183 
 1184         sx_xlock(&kld_sx);
 1185         if (uap->fileid == 0)
 1186                 lf = TAILQ_FIRST(&linker_files);
 1187         else {
 1188                 lf = linker_find_file_by_id(uap->fileid);
 1189                 if (lf == NULL) {
 1190                         error = ENOENT;
 1191                         goto out;
 1192                 }
 1193                 lf = TAILQ_NEXT(lf, link);
 1194         }
 1195 
 1196         /* Skip partially loaded files. */
 1197         while (lf != NULL && !(lf->flags & LINKER_FILE_LINKED))
 1198                 lf = TAILQ_NEXT(lf, link);
 1199 
 1200         if (lf)
 1201                 td->td_retval[0] = lf->id;
 1202         else
 1203                 td->td_retval[0] = 0;
 1204 out:
 1205         sx_xunlock(&kld_sx);
 1206         return (error);
 1207 }
 1208 
 1209 int
 1210 sys_kldstat(struct thread *td, struct kldstat_args *uap)
 1211 {
 1212         struct kld_file_stat stat;
 1213         int error, version;
 1214 
 1215         /*
 1216          * Check the version of the user's structure.
 1217          */
 1218         if ((error = copyin(&uap->stat->version, &version, sizeof(version)))
 1219             != 0)
 1220                 return (error);
 1221         if (version != sizeof(struct kld_file_stat_1) &&
 1222             version != sizeof(struct kld_file_stat))
 1223                 return (EINVAL);
 1224 
 1225         error = kern_kldstat(td, uap->fileid, &stat);
 1226         if (error != 0)
 1227                 return (error);
 1228         return (copyout(&stat, uap->stat, version));
 1229 }
 1230 
 1231 int
 1232 kern_kldstat(struct thread *td, int fileid, struct kld_file_stat *stat)
 1233 {
 1234         linker_file_t lf;
 1235         int namelen;
 1236 #ifdef MAC
 1237         int error;
 1238 
 1239         error = mac_kld_check_stat(td->td_ucred);
 1240         if (error)
 1241                 return (error);
 1242 #endif
 1243 
 1244         sx_xlock(&kld_sx);
 1245         lf = linker_find_file_by_id(fileid);
 1246         if (lf == NULL) {
 1247                 sx_xunlock(&kld_sx);
 1248                 return (ENOENT);
 1249         }
 1250 
 1251         /* Version 1 fields: */
 1252         namelen = strlen(lf->filename) + 1;
 1253         if (namelen > MAXPATHLEN)
 1254                 namelen = MAXPATHLEN;
 1255         bcopy(lf->filename, &stat->name[0], namelen);
 1256         stat->refs = lf->refs;
 1257         stat->id = lf->id;
 1258         stat->address = lf->address;
 1259         stat->size = lf->size;
 1260         /* Version 2 fields: */
 1261         namelen = strlen(lf->pathname) + 1;
 1262         if (namelen > MAXPATHLEN)
 1263                 namelen = MAXPATHLEN;
 1264         bcopy(lf->pathname, &stat->pathname[0], namelen);
 1265         sx_xunlock(&kld_sx);
 1266 
 1267         td->td_retval[0] = 0;
 1268         return (0);
 1269 }
 1270 
 1271 int
 1272 sys_kldfirstmod(struct thread *td, struct kldfirstmod_args *uap)
 1273 {
 1274         linker_file_t lf;
 1275         module_t mp;
 1276         int error = 0;
 1277 
 1278 #ifdef MAC
 1279         error = mac_kld_check_stat(td->td_ucred);
 1280         if (error)
 1281                 return (error);
 1282 #endif
 1283 
 1284         sx_xlock(&kld_sx);
 1285         lf = linker_find_file_by_id(uap->fileid);
 1286         if (lf) {
 1287                 MOD_SLOCK;
 1288                 mp = TAILQ_FIRST(&lf->modules);
 1289                 if (mp != NULL)
 1290                         td->td_retval[0] = module_getid(mp);
 1291                 else
 1292                         td->td_retval[0] = 0;
 1293                 MOD_SUNLOCK;
 1294         } else
 1295                 error = ENOENT;
 1296         sx_xunlock(&kld_sx);
 1297         return (error);
 1298 }
 1299 
 1300 int
 1301 sys_kldsym(struct thread *td, struct kldsym_args *uap)
 1302 {
 1303         char *symstr = NULL;
 1304         c_linker_sym_t sym;
 1305         linker_symval_t symval;
 1306         linker_file_t lf;
 1307         struct kld_sym_lookup lookup;
 1308         int error = 0;
 1309 
 1310 #ifdef MAC
 1311         error = mac_kld_check_stat(td->td_ucred);
 1312         if (error)
 1313                 return (error);
 1314 #endif
 1315 
 1316         if ((error = copyin(uap->data, &lookup, sizeof(lookup))) != 0)
 1317                 return (error);
 1318         if (lookup.version != sizeof(lookup) ||
 1319             uap->cmd != KLDSYM_LOOKUP)
 1320                 return (EINVAL);
 1321         symstr = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
 1322         if ((error = copyinstr(lookup.symname, symstr, MAXPATHLEN, NULL)) != 0)
 1323                 goto out;
 1324         sx_xlock(&kld_sx);
 1325         if (uap->fileid != 0) {
 1326                 lf = linker_find_file_by_id(uap->fileid);
 1327                 if (lf == NULL)
 1328                         error = ENOENT;
 1329                 else if (LINKER_LOOKUP_SYMBOL(lf, symstr, &sym) == 0 &&
 1330                     LINKER_SYMBOL_VALUES(lf, sym, &symval) == 0) {
 1331                         lookup.symvalue = (uintptr_t) symval.value;
 1332                         lookup.symsize = symval.size;
 1333                         error = copyout(&lookup, uap->data, sizeof(lookup));
 1334                 } else
 1335                         error = ENOENT;
 1336         } else {
 1337                 TAILQ_FOREACH(lf, &linker_files, link) {
 1338                         if (LINKER_LOOKUP_SYMBOL(lf, symstr, &sym) == 0 &&
 1339                             LINKER_SYMBOL_VALUES(lf, sym, &symval) == 0) {
 1340                                 lookup.symvalue = (uintptr_t)symval.value;
 1341                                 lookup.symsize = symval.size;
 1342                                 error = copyout(&lookup, uap->data,
 1343                                     sizeof(lookup));
 1344                                 break;
 1345                         }
 1346                 }
 1347                 if (lf == NULL)
 1348                         error = ENOENT;
 1349         }
 1350         sx_xunlock(&kld_sx);
 1351 out:
 1352         free(symstr, M_TEMP);
 1353         return (error);
 1354 }
 1355 
 1356 /*
 1357  * Preloaded module support
 1358  */
 1359 
 1360 static modlist_t
 1361 modlist_lookup(const char *name, int ver)
 1362 {
 1363         modlist_t mod;
 1364 
 1365         TAILQ_FOREACH(mod, &found_modules, link) {
 1366                 if (strcmp(mod->name, name) == 0 &&
 1367                     (ver == 0 || mod->version == ver))
 1368                         return (mod);
 1369         }
 1370         return (NULL);
 1371 }
 1372 
 1373 static modlist_t
 1374 modlist_lookup2(const char *name, struct mod_depend *verinfo)
 1375 {
 1376         modlist_t mod, bestmod;
 1377         int ver;
 1378 
 1379         if (verinfo == NULL)
 1380                 return (modlist_lookup(name, 0));
 1381         bestmod = NULL;
 1382         TAILQ_FOREACH(mod, &found_modules, link) {
 1383                 if (strcmp(mod->name, name) != 0)
 1384                         continue;
 1385                 ver = mod->version;
 1386                 if (ver == verinfo->md_ver_preferred)
 1387                         return (mod);
 1388                 if (ver >= verinfo->md_ver_minimum &&
 1389                     ver <= verinfo->md_ver_maximum &&
 1390                     (bestmod == NULL || ver > bestmod->version))
 1391                         bestmod = mod;
 1392         }
 1393         return (bestmod);
 1394 }
 1395 
 1396 static modlist_t
 1397 modlist_newmodule(const char *modname, int version, linker_file_t container)
 1398 {
 1399         modlist_t mod;
 1400 
 1401         mod = malloc(sizeof(struct modlist), M_LINKER, M_NOWAIT | M_ZERO);
 1402         if (mod == NULL)
 1403                 panic("no memory for module list");
 1404         mod->container = container;
 1405         mod->name = modname;
 1406         mod->version = version;
 1407         TAILQ_INSERT_TAIL(&found_modules, mod, link);
 1408         return (mod);
 1409 }
 1410 
 1411 static void
 1412 linker_addmodules(linker_file_t lf, struct mod_metadata **start,
 1413     struct mod_metadata **stop, int preload)
 1414 {
 1415         struct mod_metadata *mp, **mdp;
 1416         const char *modname;
 1417         int ver;
 1418 
 1419         for (mdp = start; mdp < stop; mdp++) {
 1420                 mp = *mdp;
 1421                 if (mp->md_type != MDT_VERSION)
 1422                         continue;
 1423                 modname = mp->md_cval;
 1424                 ver = ((struct mod_version *)mp->md_data)->mv_version;
 1425                 if (modlist_lookup(modname, ver) != NULL) {
 1426                         printf("module %s already present!\n", modname);
 1427                         /* XXX what can we do? this is a build error. :-( */
 1428                         continue;
 1429                 }
 1430                 modlist_newmodule(modname, ver, lf);
 1431         }
 1432 }
 1433 
 1434 static void
 1435 linker_preload(void *arg)
 1436 {
 1437         caddr_t modptr;
 1438         const char *modname, *nmodname;
 1439         char *modtype;
 1440         linker_file_t lf, nlf;
 1441         linker_class_t lc;
 1442         int error;
 1443         linker_file_list_t loaded_files;
 1444         linker_file_list_t depended_files;
 1445         struct mod_metadata *mp, *nmp;
 1446         struct mod_metadata **start, **stop, **mdp, **nmdp;
 1447         struct mod_depend *verinfo;
 1448         int nver;
 1449         int resolves;
 1450         modlist_t mod;
 1451         struct sysinit **si_start, **si_stop;
 1452 
 1453         TAILQ_INIT(&loaded_files);
 1454         TAILQ_INIT(&depended_files);
 1455         TAILQ_INIT(&found_modules);
 1456         error = 0;
 1457 
 1458         modptr = NULL;
 1459         sx_xlock(&kld_sx);
 1460         while ((modptr = preload_search_next_name(modptr)) != NULL) {
 1461                 modname = (char *)preload_search_info(modptr, MODINFO_NAME);
 1462                 modtype = (char *)preload_search_info(modptr, MODINFO_TYPE);
 1463                 if (modname == NULL) {
 1464                         printf("Preloaded module at %p does not have a"
 1465                             " name!\n", modptr);
 1466                         continue;
 1467                 }
 1468                 if (modtype == NULL) {
 1469                         printf("Preloaded module at %p does not have a type!\n",
 1470                             modptr);
 1471                         continue;
 1472                 }
 1473                 if (bootverbose)
 1474                         printf("Preloaded %s \"%s\" at %p.\n", modtype, modname,
 1475                             modptr);
 1476                 lf = NULL;
 1477                 TAILQ_FOREACH(lc, &classes, link) {
 1478                         error = LINKER_LINK_PRELOAD(lc, modname, &lf);
 1479                         if (!error)
 1480                                 break;
 1481                         lf = NULL;
 1482                 }
 1483                 if (lf)
 1484                         TAILQ_INSERT_TAIL(&loaded_files, lf, loaded);
 1485         }
 1486 
 1487         /*
 1488          * First get a list of stuff in the kernel.
 1489          */
 1490         if (linker_file_lookup_set(linker_kernel_file, MDT_SETNAME, &start,
 1491             &stop, NULL) == 0)
 1492                 linker_addmodules(linker_kernel_file, start, stop, 1);
 1493 
 1494         /*
 1495          * This is a once-off kinky bubble sort to resolve relocation
 1496          * dependency requirements.
 1497          */
 1498 restart:
 1499         TAILQ_FOREACH(lf, &loaded_files, loaded) {
 1500                 error = linker_file_lookup_set(lf, MDT_SETNAME, &start,
 1501                     &stop, NULL);
 1502                 /*
 1503                  * First, look to see if we would successfully link with this
 1504                  * stuff.
 1505                  */
 1506                 resolves = 1;   /* unless we know otherwise */
 1507                 if (!error) {
 1508                         for (mdp = start; mdp < stop; mdp++) {
 1509                                 mp = *mdp;
 1510                                 if (mp->md_type != MDT_DEPEND)
 1511                                         continue;
 1512                                 modname = mp->md_cval;
 1513                                 verinfo = mp->md_data;
 1514                                 for (nmdp = start; nmdp < stop; nmdp++) {
 1515                                         nmp = *nmdp;
 1516                                         if (nmp->md_type != MDT_VERSION)
 1517                                                 continue;
 1518                                         nmodname = nmp->md_cval;
 1519                                         if (strcmp(modname, nmodname) == 0)
 1520                                                 break;
 1521                                 }
 1522                                 if (nmdp < stop)   /* it's a self reference */
 1523                                         continue;
 1524 
 1525                                 /*
 1526                                  * ok, the module isn't here yet, we
 1527                                  * are not finished
 1528                                  */
 1529                                 if (modlist_lookup2(modname, verinfo) == NULL)
 1530                                         resolves = 0;
 1531                         }
 1532                 }
 1533                 /*
 1534                  * OK, if we found our modules, we can link.  So, "provide"
 1535                  * the modules inside and add it to the end of the link order
 1536                  * list.
 1537                  */
 1538                 if (resolves) {
 1539                         if (!error) {
 1540                                 for (mdp = start; mdp < stop; mdp++) {
 1541                                         mp = *mdp;
 1542                                         if (mp->md_type != MDT_VERSION)
 1543                                                 continue;
 1544                                         modname = mp->md_cval;
 1545                                         nver = ((struct mod_version *)
 1546                                             mp->md_data)->mv_version;
 1547                                         if (modlist_lookup(modname,
 1548                                             nver) != NULL) {
 1549                                                 printf("module %s already"
 1550                                                     " present!\n", modname);
 1551                                                 TAILQ_REMOVE(&loaded_files,
 1552                                                     lf, loaded);
 1553                                                 linker_file_unload(lf,
 1554                                                     LINKER_UNLOAD_FORCE);
 1555                                                 /* we changed tailq next ptr */
 1556                                                 goto restart;
 1557                                         }
 1558                                         modlist_newmodule(modname, nver, lf);
 1559                                 }
 1560                         }
 1561                         TAILQ_REMOVE(&loaded_files, lf, loaded);
 1562                         TAILQ_INSERT_TAIL(&depended_files, lf, loaded);
 1563                         /*
 1564                          * Since we provided modules, we need to restart the
 1565                          * sort so that the previous files that depend on us
 1566                          * have a chance. Also, we've busted the tailq next
 1567                          * pointer with the REMOVE.
 1568                          */
 1569                         goto restart;
 1570                 }
 1571         }
 1572 
 1573         /*
 1574          * At this point, we check to see what could not be resolved..
 1575          */
 1576         while ((lf = TAILQ_FIRST(&loaded_files)) != NULL) {
 1577                 TAILQ_REMOVE(&loaded_files, lf, loaded);
 1578                 printf("KLD file %s is missing dependencies\n", lf->filename);
 1579                 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
 1580         }
 1581 
 1582         /*
 1583          * We made it. Finish off the linking in the order we determined.
 1584          */
 1585         TAILQ_FOREACH_SAFE(lf, &depended_files, loaded, nlf) {
 1586                 if (linker_kernel_file) {
 1587                         linker_kernel_file->refs++;
 1588                         error = linker_file_add_dependency(lf,
 1589                             linker_kernel_file);
 1590                         if (error)
 1591                                 panic("cannot add dependency");
 1592                 }
 1593                 lf->userrefs++; /* so we can (try to) kldunload it */
 1594                 error = linker_file_lookup_set(lf, MDT_SETNAME, &start,
 1595                     &stop, NULL);
 1596                 if (!error) {
 1597                         for (mdp = start; mdp < stop; mdp++) {
 1598                                 mp = *mdp;
 1599                                 if (mp->md_type != MDT_DEPEND)
 1600                                         continue;
 1601                                 modname = mp->md_cval;
 1602                                 verinfo = mp->md_data;
 1603                                 mod = modlist_lookup2(modname, verinfo);
 1604                                 if (mod == NULL) {
 1605                                         printf("KLD file %s - cannot find "
 1606                                             "dependency \"%s\"\n",
 1607                                             lf->filename, modname);
 1608                                         goto fail;
 1609                                 }
 1610                                 /* Don't count self-dependencies */
 1611                                 if (lf == mod->container)
 1612                                         continue;
 1613                                 mod->container->refs++;
 1614                                 error = linker_file_add_dependency(lf,
 1615                                     mod->container);
 1616                                 if (error)
 1617                                         panic("cannot add dependency");
 1618                         }
 1619                 }
 1620                 /*
 1621                  * Now do relocation etc using the symbol search paths
 1622                  * established by the dependencies
 1623                  */
 1624                 error = LINKER_LINK_PRELOAD_FINISH(lf);
 1625                 if (error) {
 1626                         printf("KLD file %s - could not finalize loading\n",
 1627                             lf->filename);
 1628                         goto fail;
 1629                 }
 1630                 linker_file_register_modules(lf);
 1631                 if (linker_file_lookup_set(lf, "sysinit_set", &si_start,
 1632                     &si_stop, NULL) == 0)
 1633                         sysinit_add(si_start, si_stop);
 1634                 linker_file_register_sysctls(lf);
 1635                 lf->flags |= LINKER_FILE_LINKED;
 1636                 continue;
 1637 fail:
 1638                 TAILQ_REMOVE(&depended_files, lf, loaded);
 1639                 linker_file_unload(lf, LINKER_UNLOAD_FORCE);
 1640         }
 1641         sx_xunlock(&kld_sx);
 1642         /* woohoo! we made it! */
 1643 }
 1644 
 1645 SYSINIT(preload, SI_SUB_KLD, SI_ORDER_MIDDLE, linker_preload, 0);
 1646 
 1647 /*
 1648  * Search for a not-loaded module by name.
 1649  *
 1650  * Modules may be found in the following locations:
 1651  *
 1652  * - preloaded (result is just the module name) - on disk (result is full path
 1653  * to module)
 1654  *
 1655  * If the module name is qualified in any way (contains path, etc.) the we
 1656  * simply return a copy of it.
 1657  *
 1658  * The search path can be manipulated via sysctl.  Note that we use the ';'
 1659  * character as a separator to be consistent with the bootloader.
 1660  */
 1661 
 1662 static char linker_hintfile[] = "linker.hints";
 1663 static char linker_path[MAXPATHLEN] = "/boot/kernel;/boot/modules";
 1664 
 1665 SYSCTL_STRING(_kern, OID_AUTO, module_path, CTLFLAG_RW, linker_path,
 1666     sizeof(linker_path), "module load search path");
 1667 
 1668 TUNABLE_STR("module_path", linker_path, sizeof(linker_path));
 1669 
 1670 static char *linker_ext_list[] = {
 1671         "",
 1672         ".ko",
 1673         NULL
 1674 };
 1675 
 1676 /*
 1677  * Check if file actually exists either with or without extension listed in
 1678  * the linker_ext_list. (probably should be generic for the rest of the
 1679  * kernel)
 1680  */
 1681 static char *
 1682 linker_lookup_file(const char *path, int pathlen, const char *name,
 1683     int namelen, struct vattr *vap)
 1684 {
 1685         struct nameidata nd;
 1686         struct thread *td = curthread;  /* XXX */
 1687         char *result, **cpp, *sep;
 1688         int error, len, extlen, reclen, flags;
 1689         enum vtype type;
 1690 
 1691         extlen = 0;
 1692         for (cpp = linker_ext_list; *cpp; cpp++) {
 1693                 len = strlen(*cpp);
 1694                 if (len > extlen)
 1695                         extlen = len;
 1696         }
 1697         extlen++;               /* trailing '\0' */
 1698         sep = (path[pathlen - 1] != '/') ? "/" : "";
 1699 
 1700         reclen = pathlen + strlen(sep) + namelen + extlen + 1;
 1701         result = malloc(reclen, M_LINKER, M_WAITOK);
 1702         for (cpp = linker_ext_list; *cpp; cpp++) {
 1703                 snprintf(result, reclen, "%.*s%s%.*s%s", pathlen, path, sep,
 1704                     namelen, name, *cpp);
 1705                 /*
 1706                  * Attempt to open the file, and return the path if
 1707                  * we succeed and it's a regular file.
 1708                  */
 1709                 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, result, td);
 1710                 flags = FREAD;
 1711                 error = vn_open(&nd, &flags, 0, NULL);
 1712                 if (error == 0) {
 1713                         NDFREE(&nd, NDF_ONLY_PNBUF);
 1714                         type = nd.ni_vp->v_type;
 1715                         if (vap)
 1716                                 VOP_GETATTR(nd.ni_vp, vap, td->td_ucred);
 1717                         VOP_UNLOCK(nd.ni_vp, 0);
 1718                         vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
 1719                         if (type == VREG)
 1720                                 return (result);
 1721                 }
 1722         }
 1723         free(result, M_LINKER);
 1724         return (NULL);
 1725 }
 1726 
 1727 #define INT_ALIGN(base, ptr)    ptr =                                   \
 1728         (base) + (((ptr) - (base) + sizeof(int) - 1) & ~(sizeof(int) - 1))
 1729 
 1730 /*
 1731  * Lookup KLD which contains requested module in the "linker.hints" file. If
 1732  * version specification is available, then try to find the best KLD.
 1733  * Otherwise just find the latest one.
 1734  */
 1735 static char *
 1736 linker_hints_lookup(const char *path, int pathlen, const char *modname,
 1737     int modnamelen, struct mod_depend *verinfo)
 1738 {
 1739         struct thread *td = curthread;  /* XXX */
 1740         struct ucred *cred = td ? td->td_ucred : NULL;
 1741         struct nameidata nd;
 1742         struct vattr vattr, mattr;
 1743         u_char *hints = NULL;
 1744         u_char *cp, *recptr, *bufend, *result, *best, *pathbuf, *sep;
 1745         int error, ival, bestver, *intp, found, flags, clen, blen;
 1746         ssize_t reclen;
 1747 
 1748         result = NULL;
 1749         bestver = found = 0;
 1750 
 1751         sep = (path[pathlen - 1] != '/') ? "/" : "";
 1752         reclen = imax(modnamelen, strlen(linker_hintfile)) + pathlen +
 1753             strlen(sep) + 1;
 1754         pathbuf = malloc(reclen, M_LINKER, M_WAITOK);
 1755         snprintf(pathbuf, reclen, "%.*s%s%s", pathlen, path, sep,
 1756             linker_hintfile);
 1757 
 1758         NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, pathbuf, td);
 1759         flags = FREAD;
 1760         error = vn_open(&nd, &flags, 0, NULL);
 1761         if (error)
 1762                 goto bad;
 1763         NDFREE(&nd, NDF_ONLY_PNBUF);
 1764         if (nd.ni_vp->v_type != VREG)
 1765                 goto bad;
 1766         best = cp = NULL;
 1767         error = VOP_GETATTR(nd.ni_vp, &vattr, cred);
 1768         if (error)
 1769                 goto bad;
 1770         /*
 1771          * XXX: we need to limit this number to some reasonable value
 1772          */
 1773         if (vattr.va_size > 100 * 1024) {
 1774                 printf("hints file too large %ld\n", (long)vattr.va_size);
 1775                 goto bad;
 1776         }
 1777         hints = malloc(vattr.va_size, M_TEMP, M_WAITOK);
 1778         if (hints == NULL)
 1779                 goto bad;
 1780         error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)hints, vattr.va_size, 0,
 1781             UIO_SYSSPACE, IO_NODELOCKED, cred, NOCRED, &reclen, td);
 1782         if (error)
 1783                 goto bad;
 1784         VOP_UNLOCK(nd.ni_vp, 0);
 1785         vn_close(nd.ni_vp, FREAD, cred, td);
 1786         nd.ni_vp = NULL;
 1787         if (reclen != 0) {
 1788                 printf("can't read %zd\n", reclen);
 1789                 goto bad;
 1790         }
 1791         intp = (int *)hints;
 1792         ival = *intp++;
 1793         if (ival != LINKER_HINTS_VERSION) {
 1794                 printf("hints file version mismatch %d\n", ival);
 1795                 goto bad;
 1796         }
 1797         bufend = hints + vattr.va_size;
 1798         recptr = (u_char *)intp;
 1799         clen = blen = 0;
 1800         while (recptr < bufend && !found) {
 1801                 intp = (int *)recptr;
 1802                 reclen = *intp++;
 1803                 ival = *intp++;
 1804                 cp = (char *)intp;
 1805                 switch (ival) {
 1806                 case MDT_VERSION:
 1807                         clen = *cp++;
 1808                         if (clen != modnamelen || bcmp(cp, modname, clen) != 0)
 1809                                 break;
 1810                         cp += clen;
 1811                         INT_ALIGN(hints, cp);
 1812                         ival = *(int *)cp;
 1813                         cp += sizeof(int);
 1814                         clen = *cp++;
 1815                         if (verinfo == NULL ||
 1816                             ival == verinfo->md_ver_preferred) {
 1817                                 found = 1;
 1818                                 break;
 1819                         }
 1820                         if (ival >= verinfo->md_ver_minimum &&
 1821                             ival <= verinfo->md_ver_maximum &&
 1822                             ival > bestver) {
 1823                                 bestver = ival;
 1824                                 best = cp;
 1825                                 blen = clen;
 1826                         }
 1827                         break;
 1828                 default:
 1829                         break;
 1830                 }
 1831                 recptr += reclen + sizeof(int);
 1832         }
 1833         /*
 1834          * Finally check if KLD is in the place
 1835          */
 1836         if (found)
 1837                 result = linker_lookup_file(path, pathlen, cp, clen, &mattr);
 1838         else if (best)
 1839                 result = linker_lookup_file(path, pathlen, best, blen, &mattr);
 1840 
 1841         /*
 1842          * KLD is newer than hints file. What we should do now?
 1843          */
 1844         if (result && timespeccmp(&mattr.va_mtime, &vattr.va_mtime, >))
 1845                 printf("warning: KLD '%s' is newer than the linker.hints"
 1846                     " file\n", result);
 1847 bad:
 1848         free(pathbuf, M_LINKER);
 1849         if (hints)
 1850                 free(hints, M_TEMP);
 1851         if (nd.ni_vp != NULL) {
 1852                 VOP_UNLOCK(nd.ni_vp, 0);
 1853                 vn_close(nd.ni_vp, FREAD, cred, td);
 1854         }
 1855         /*
 1856          * If nothing found or hints is absent - fallback to the old
 1857          * way by using "kldname[.ko]" as module name.
 1858          */
 1859         if (!found && !bestver && result == NULL)
 1860                 result = linker_lookup_file(path, pathlen, modname,
 1861                     modnamelen, NULL);
 1862         return (result);
 1863 }
 1864 
 1865 /*
 1866  * Lookup KLD which contains requested module in the all directories.
 1867  */
 1868 static char *
 1869 linker_search_module(const char *modname, int modnamelen,
 1870     struct mod_depend *verinfo)
 1871 {
 1872         char *cp, *ep, *result;
 1873 
 1874         /*
 1875          * traverse the linker path
 1876          */
 1877         for (cp = linker_path; *cp; cp = ep + 1) {
 1878                 /* find the end of this component */
 1879                 for (ep = cp; (*ep != 0) && (*ep != ';'); ep++);
 1880                 result = linker_hints_lookup(cp, ep - cp, modname,
 1881                     modnamelen, verinfo);
 1882                 if (result != NULL)
 1883                         return (result);
 1884                 if (*ep == 0)
 1885                         break;
 1886         }
 1887         return (NULL);
 1888 }
 1889 
 1890 /*
 1891  * Search for module in all directories listed in the linker_path.
 1892  */
 1893 static char *
 1894 linker_search_kld(const char *name)
 1895 {
 1896         char *cp, *ep, *result;
 1897         int len;
 1898 
 1899         /* qualified at all? */
 1900         if (strchr(name, '/'))
 1901                 return (strdup(name, M_LINKER));
 1902 
 1903         /* traverse the linker path */
 1904         len = strlen(name);
 1905         for (ep = linker_path; *ep; ep++) {
 1906                 cp = ep;
 1907                 /* find the end of this component */
 1908                 for (; *ep != 0 && *ep != ';'; ep++);
 1909                 result = linker_lookup_file(cp, ep - cp, name, len, NULL);
 1910                 if (result != NULL)
 1911                         return (result);
 1912         }
 1913         return (NULL);
 1914 }
 1915 
 1916 static const char *
 1917 linker_basename(const char *path)
 1918 {
 1919         const char *filename;
 1920 
 1921         filename = strrchr(path, '/');
 1922         if (filename == NULL)
 1923                 return path;
 1924         if (filename[1])
 1925                 filename++;
 1926         return (filename);
 1927 }
 1928 
 1929 #ifdef HWPMC_HOOKS
 1930 /*
 1931  * Inform hwpmc about the set of kernel modules currently loaded.
 1932  */
 1933 void *
 1934 linker_hwpmc_list_objects(void)
 1935 {
 1936         linker_file_t lf;
 1937         struct pmckern_map_in *kobase;
 1938         int i, nmappings;
 1939 
 1940         nmappings = 0;
 1941         sx_slock(&kld_sx);
 1942         TAILQ_FOREACH(lf, &linker_files, link)
 1943                 nmappings++;
 1944 
 1945         /* Allocate nmappings + 1 entries. */
 1946         kobase = malloc((nmappings + 1) * sizeof(struct pmckern_map_in),
 1947             M_LINKER, M_WAITOK | M_ZERO);
 1948         i = 0;
 1949         TAILQ_FOREACH(lf, &linker_files, link) {
 1950 
 1951                 /* Save the info for this linker file. */
 1952                 kobase[i].pm_file = lf->filename;
 1953                 kobase[i].pm_address = (uintptr_t)lf->address;
 1954                 i++;
 1955         }
 1956         sx_sunlock(&kld_sx);
 1957 
 1958         KASSERT(i > 0, ("linker_hpwmc_list_objects: no kernel objects?"));
 1959 
 1960         /* The last entry of the malloced area comprises of all zeros. */
 1961         KASSERT(kobase[i].pm_file == NULL,
 1962             ("linker_hwpmc_list_objects: last object not NULL"));
 1963 
 1964         return ((void *)kobase);
 1965 }
 1966 #endif
 1967 
 1968 /*
 1969  * Find a file which contains given module and load it, if "parent" is not
 1970  * NULL, register a reference to it.
 1971  */
 1972 static int
 1973 linker_load_module(const char *kldname, const char *modname,
 1974     struct linker_file *parent, struct mod_depend *verinfo,
 1975     struct linker_file **lfpp)
 1976 {
 1977         linker_file_t lfdep;
 1978         const char *filename;
 1979         char *pathname;
 1980         int error;
 1981 
 1982         sx_assert(&kld_sx, SA_XLOCKED);
 1983         if (modname == NULL) {
 1984                 /*
 1985                  * We have to load KLD
 1986                  */
 1987                 KASSERT(verinfo == NULL, ("linker_load_module: verinfo"
 1988                     " is not NULL"));
 1989                 pathname = linker_search_kld(kldname);
 1990         } else {
 1991                 if (modlist_lookup2(modname, verinfo) != NULL)
 1992                         return (EEXIST);
 1993                 if (kldname != NULL)
 1994                         pathname = strdup(kldname, M_LINKER);
 1995                 else if (rootvnode == NULL)
 1996                         pathname = NULL;
 1997                 else
 1998                         /*
 1999                          * Need to find a KLD with required module
 2000                          */
 2001                         pathname = linker_search_module(modname,
 2002                             strlen(modname), verinfo);
 2003         }
 2004         if (pathname == NULL)
 2005                 return (ENOENT);
 2006 
 2007         /*
 2008          * Can't load more than one file with the same basename XXX:
 2009          * Actually it should be possible to have multiple KLDs with
 2010          * the same basename but different path because they can
 2011          * provide different versions of the same modules.
 2012          */
 2013         filename = linker_basename(pathname);
 2014         if (linker_find_file_by_name(filename))
 2015                 error = EEXIST;
 2016         else do {
 2017                 error = linker_load_file(pathname, &lfdep);
 2018                 if (error)
 2019                         break;
 2020                 if (modname && verinfo &&
 2021                     modlist_lookup2(modname, verinfo) == NULL) {
 2022                         linker_file_unload(lfdep, LINKER_UNLOAD_FORCE);
 2023                         error = ENOENT;
 2024                         break;
 2025                 }
 2026                 if (parent) {
 2027                         error = linker_file_add_dependency(parent, lfdep);
 2028                         if (error)
 2029                                 break;
 2030                 }
 2031                 if (lfpp)
 2032                         *lfpp = lfdep;
 2033         } while (0);
 2034         free(pathname, M_LINKER);
 2035         return (error);
 2036 }
 2037 
 2038 /*
 2039  * This routine is responsible for finding dependencies of userland initiated
 2040  * kldload(2)'s of files.
 2041  */
 2042 int
 2043 linker_load_dependencies(linker_file_t lf)
 2044 {
 2045         linker_file_t lfdep;
 2046         struct mod_metadata **start, **stop, **mdp, **nmdp;
 2047         struct mod_metadata *mp, *nmp;
 2048         struct mod_depend *verinfo;
 2049         modlist_t mod;
 2050         const char *modname, *nmodname;
 2051         int ver, error = 0, count;
 2052 
 2053         /*
 2054          * All files are dependant on /kernel.
 2055          */
 2056         sx_assert(&kld_sx, SA_XLOCKED);
 2057         if (linker_kernel_file) {
 2058                 linker_kernel_file->refs++;
 2059                 error = linker_file_add_dependency(lf, linker_kernel_file);
 2060                 if (error)
 2061                         return (error);
 2062         }
 2063         if (linker_file_lookup_set(lf, MDT_SETNAME, &start, &stop,
 2064             &count) != 0)
 2065                 return (0);
 2066         for (mdp = start; mdp < stop; mdp++) {
 2067                 mp = *mdp;
 2068                 if (mp->md_type != MDT_VERSION)
 2069                         continue;
 2070                 modname = mp->md_cval;
 2071                 ver = ((struct mod_version *)mp->md_data)->mv_version;
 2072                 mod = modlist_lookup(modname, ver);
 2073                 if (mod != NULL) {
 2074                         printf("interface %s.%d already present in the KLD"
 2075                             " '%s'!\n", modname, ver,
 2076                             mod->container->filename);
 2077                         return (EEXIST);
 2078                 }
 2079         }
 2080 
 2081         for (mdp = start; mdp < stop; mdp++) {
 2082                 mp = *mdp;
 2083                 if (mp->md_type != MDT_DEPEND)
 2084                         continue;
 2085                 modname = mp->md_cval;
 2086                 verinfo = mp->md_data;
 2087                 nmodname = NULL;
 2088                 for (nmdp = start; nmdp < stop; nmdp++) {
 2089                         nmp = *nmdp;
 2090                         if (nmp->md_type != MDT_VERSION)
 2091                                 continue;
 2092                         nmodname = nmp->md_cval;
 2093                         if (strcmp(modname, nmodname) == 0)
 2094                                 break;
 2095                 }
 2096                 if (nmdp < stop)/* early exit, it's a self reference */
 2097                         continue;
 2098                 mod = modlist_lookup2(modname, verinfo);
 2099                 if (mod) {      /* woohoo, it's loaded already */
 2100                         lfdep = mod->container;
 2101                         lfdep->refs++;
 2102                         error = linker_file_add_dependency(lf, lfdep);
 2103                         if (error)
 2104                                 break;
 2105                         continue;
 2106                 }
 2107                 error = linker_load_module(NULL, modname, lf, verinfo, NULL);
 2108                 if (error) {
 2109                         printf("KLD %s: depends on %s - not available or"
 2110                             " version mismatch\n", lf->filename, modname);
 2111                         break;
 2112                 }
 2113         }
 2114 
 2115         if (error)
 2116                 return (error);
 2117         linker_addmodules(lf, start, stop, 0);
 2118         return (error);
 2119 }
 2120 
 2121 static int
 2122 sysctl_kern_function_list_iterate(const char *name, void *opaque)
 2123 {
 2124         struct sysctl_req *req;
 2125 
 2126         req = opaque;
 2127         return (SYSCTL_OUT(req, name, strlen(name) + 1));
 2128 }
 2129 
 2130 /*
 2131  * Export a nul-separated, double-nul-terminated list of all function names
 2132  * in the kernel.
 2133  */
 2134 static int
 2135 sysctl_kern_function_list(SYSCTL_HANDLER_ARGS)
 2136 {
 2137         linker_file_t lf;
 2138         int error;
 2139 
 2140 #ifdef MAC
 2141         error = mac_kld_check_stat(req->td->td_ucred);
 2142         if (error)
 2143                 return (error);
 2144 #endif
 2145         error = sysctl_wire_old_buffer(req, 0);
 2146         if (error != 0)
 2147                 return (error);
 2148         sx_xlock(&kld_sx);
 2149         TAILQ_FOREACH(lf, &linker_files, link) {
 2150                 error = LINKER_EACH_FUNCTION_NAME(lf,
 2151                     sysctl_kern_function_list_iterate, req);
 2152                 if (error) {
 2153                         sx_xunlock(&kld_sx);
 2154                         return (error);
 2155                 }
 2156         }
 2157         sx_xunlock(&kld_sx);
 2158         return (SYSCTL_OUT(req, "", 1));
 2159 }
 2160 
 2161 SYSCTL_PROC(_kern, OID_AUTO, function_list, CTLTYPE_OPAQUE | CTLFLAG_RD,
 2162     NULL, 0, sysctl_kern_function_list, "", "kernel function list");

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