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

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