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

     /*-
      * Copyright (c) 1997 Doug Rabson
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
      *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     * $FreeBSD: src/sys/kern/kern_linker.c,v 1.41.2.3 2001/11/21 17:50:35 luigi Exp $
     */
    
    #include "opt_ddb.h"
    
    #include <sys/param.h>
    #include <sys/kernel.h>
    #include <sys/systm.h>
    #include <sys/malloc.h>
    #include <sys/sysproto.h>
    #include <sys/sysent.h>
    #include <sys/proc.h>
    #include <sys/priv.h>
    #include <sys/lock.h>
    #include <sys/module.h>
    #include <sys/queue.h>
    #include <sys/linker.h>
    #include <sys/fcntl.h>
    #include <sys/libkern.h>
    #include <sys/nlookup.h>
    #include <sys/vnode.h>
    #include <sys/sysctl.h>
    
    #include <vm/vm_zone.h>
    
    #include <sys/mplock2.h>
    
    #ifdef _KERNEL_VIRTUAL
    #include <dlfcn.h>
    #endif
    
    #ifdef KLD_DEBUG
    int kld_debug = 1;
    #endif
    
    /* Metadata from the static kernel */
    SET_DECLARE(modmetadata_set, struct mod_metadata);
    MALLOC_DEFINE(M_LINKER, "kld", "kernel linker");
    
    linker_file_t linker_current_file;
    linker_file_t linker_kernel_file;
    
    static struct lock lock;        /* lock for the file list */
    static linker_class_list_t classes;
    static linker_file_list_t linker_files;
    static int next_file_id = 1;
    
    /* XXX wrong name; we're looking at version provision tags here, not modules */
    typedef TAILQ_HEAD(, modlist) modlisthead_t;
    struct modlist {
            TAILQ_ENTRY(modlist) link;      /* chain together all modules */
            linker_file_t   container;
            const char      *name;
            int             version;
    };
    typedef struct modlist *modlist_t;
    static modlisthead_t found_modules;
    
    
    static int linker_load_module(const char *kldname, const char *modname,
                                  struct linker_file *parent, struct mod_depend *verinfo,
                                  struct linker_file **lfpp);
    
    static char *
    linker_strdup(const char *str)
    {
        char        *result;
    
        result = kmalloc(strlen(str) + 1, M_LINKER, M_WAITOK);
        strcpy(result, str);
        return(result);
    }
    
    static void
   linker_init(void* arg)
   {
       lockinit(&lock, "klink", 0, 0);
       TAILQ_INIT(&classes);
       TAILQ_INIT(&linker_files);
   }
   
   SYSINIT(linker, SI_BOOT2_KLD, SI_ORDER_FIRST, linker_init, 0);
   
   int
   linker_add_class(const char* desc, void* priv,
                    struct linker_class_ops* ops)
   {
       linker_class_t lc;
   
       lc = kmalloc(sizeof(struct linker_class), M_LINKER, M_NOWAIT | M_ZERO);
       if (!lc)
           return ENOMEM;
   
       lc->desc = desc;
       lc->priv = priv;
       lc->ops = ops;
       TAILQ_INSERT_HEAD(&classes, lc, link);
   
       return 0;
   }
   
   static void
   linker_file_sysinit(linker_file_t lf)
   {
       struct sysinit** start, ** stop;
       struct sysinit** sipp;
       struct sysinit** xipp;
       struct sysinit* save;
   
       KLD_DPF(FILE, ("linker_file_sysinit: calling SYSINITs for %s\n",
                      lf->filename));
   
       if (linker_file_lookup_set(lf, "sysinit_set", &start, &stop, NULL) != 0)
           return;
   
       /*
        * Perform a bubble sort of the system initialization objects by
        * their subsystem (primary key) and order (secondary key).
        *
        * Since some things care about execution order, this is the
        * operation which ensures continued function.
        */
       for (sipp = start; sipp < stop; sipp++) {
           for (xipp = sipp + 1; xipp < stop; xipp++) {
               if ((*sipp)->subsystem < (*xipp)->subsystem ||
                    ((*sipp)->subsystem == (*xipp)->subsystem &&
                     (*sipp)->order <= (*xipp)->order))
                   continue;       /* skip*/
               save = *sipp;
               *sipp = *xipp;
               *xipp = save;
           }
       }
   
   
       /*
        * Traverse the (now) ordered list of system initialization tasks.
        * Perform each task, and continue on to the next task.
        */
       for (sipp = start; sipp < stop; sipp++) {
           if ((*sipp)->subsystem == SI_SPECIAL_DUMMY)
               continue;   /* skip dummy task(s)*/
   
           /* Call function */
           (*((*sipp)->func))((*sipp)->udata);
       }
   }
   
   static void
   linker_file_sysuninit(linker_file_t lf)
   {
       struct sysinit** start, ** stop;
       struct sysinit** sipp;
       struct sysinit** xipp;
       struct sysinit* save;
   
       KLD_DPF(FILE, ("linker_file_sysuninit: calling SYSUNINITs for %s\n",
                      lf->filename));
   
       if (linker_file_lookup_set(lf, "sysuninit_set", &start, &stop, NULL) != 0)
           return;
   
       /*
        * Perform a reverse bubble sort of the system initialization objects
        * by their subsystem (primary key) and order (secondary key).
        *
        * Since some things care about execution order, this is the
        * operation which ensures continued function.
        */
       for (sipp = start; sipp < stop; sipp++) {
           for (xipp = sipp + 1; xipp < stop; xipp++) {
               if ((*sipp)->subsystem > (*xipp)->subsystem ||
                    ((*sipp)->subsystem == (*xipp)->subsystem &&
                     (*sipp)->order >= (*xipp)->order))
                   continue;       /* skip*/
               save = *sipp;
               *sipp = *xipp;
               *xipp = save;
           }
       }
   
   
       /*
        * Traverse the (now) ordered list of system initialization tasks.
        * Perform each task, and continue on to the next task.
        */
       for (sipp = start; sipp < stop; sipp++) {
           if ((*sipp)->subsystem == SI_SPECIAL_DUMMY)
               continue;   /* skip dummy task(s)*/
   
           /* Call function */
           (*((*sipp)->func))((*sipp)->udata);
       }
   }
   
   static void
   linker_file_register_sysctls(linker_file_t lf)
   {
       struct sysctl_oid **start, **stop, **oidp;
   
       KLD_DPF(FILE, ("linker_file_register_sysctls: registering SYSCTLs for %s\n",
                      lf->filename));
   
       if (linker_file_lookup_set(lf, "sysctl_set", &start, &stop, NULL) != 0)
           return;
       for (oidp = start; oidp < stop; oidp++)
           sysctl_register_oid(*oidp);
   }
   
   static void
   linker_file_unregister_sysctls(linker_file_t lf)
   {
       struct sysctl_oid **start, **stop, **oidp;
   
       KLD_DPF(FILE, ("linker_file_unregister_sysctls: registering SYSCTLs for %s\n",
                      lf->filename));
   
       if (linker_file_lookup_set(lf, "sysctl_set", &start, &stop, NULL) != 0)
           return;
       for (oidp = start; oidp < stop; oidp++)
           sysctl_unregister_oid(*oidp);
   }
   
   static int
   linker_file_register_modules(linker_file_t lf)
   {
       struct mod_metadata **start, **stop, **mdp;
       const moduledata_t *moddata;
       int             first_error, error;
   
       KLD_DPF(FILE, ("linker_file_register_modules: registering modules in %s\n",
                      lf->filename));
   
       if (linker_file_lookup_set(lf, "modmetadata_set", &start, &stop, NULL) != 0) {
           /*
            * This fallback should be unnecessary, but if we get booted
            * from boot2 instead of loader and we are missing our
            * metadata then we have to try the best we can.
            */
           if (lf == linker_kernel_file) {
               start = SET_BEGIN(modmetadata_set);
               stop = SET_LIMIT(modmetadata_set);
           } else
               return (0);
       }
       first_error = 0;
       for (mdp = start; mdp < stop; mdp++) {
           if ((*mdp)->md_type != MDT_MODULE)
               continue;
           moddata = (*mdp)->md_data;
           KLD_DPF(FILE, ("Registering module %s in %s\n", moddata->name, lf->filename));
           error = module_register(moddata, lf);
           if (error) {
               kprintf("Module %s failed to register: %d\n", moddata->name, error);
               if (first_error == 0)
                   first_error = error;
           }
       }
       return (first_error);
   }
   
   static void
   linker_init_kernel_modules(void)
   {
   
       linker_file_register_modules(linker_kernel_file);
   }
   
   SYSINIT(linker_kernel, SI_BOOT2_KLD, SI_ORDER_ANY, linker_init_kernel_modules, 0);
   
   int
   linker_load_file(const char *filename, linker_file_t *result)
   {
       linker_class_t lc;
       linker_file_t lf;
       int foundfile, error = 0;
   
       /* Refuse to load modules if securelevel raised */
       if (securelevel > 0 || kernel_mem_readonly)
           return EPERM; 
   
       lf = linker_find_file_by_name(filename);
       if (lf) {
           KLD_DPF(FILE, ("linker_load_file: file %s is already loaded, incrementing refs\n", filename));
           *result = lf;
           lf->refs++;
           goto out;
       }
   
       lf = NULL;
       foundfile = 0;
       TAILQ_FOREACH(lc, &classes, link) {
           KLD_DPF(FILE, ("linker_load_file: trying to load %s as %s\n",
                          filename, lc->desc));
   
           error = lc->ops->load_file(filename, &lf);
           /*
            * If we got something other than ENOENT, then it exists but we cannot
            * load it for some other reason.
            */
           if (error != ENOENT)
               foundfile = 1;
           if (lf) {
               error = linker_file_register_modules(lf);
               if (error == EEXIST) {
                       linker_file_unload(lf /* , LINKER_UNLOAD_FORCE */);
                       return (error);
               }
               linker_file_register_sysctls(lf);
               linker_file_sysinit(lf);
               lf->flags |= LINKER_FILE_LINKED;
               *result = lf;
               return (0);
           }
       }
       /*
        * Less than ideal, but tells the user whether it failed to load or
        * the module was not found.
        */
       if (foundfile) {
               /*
                * If the file type has not been recognized by the last try
                * printout a message before to fail.
                */
               if (error == ENOSYS)
                       kprintf("linker_load_file: Unsupported file type\n");
   
               /*
                * Format not recognized or otherwise unloadable.
                * When loading a module that is statically built into
                * the kernel EEXIST percolates back up as the return
                * value.  Preserve this so that apps can recognize this
                * special case.
                */
               if (error != EEXIST)
                       error = ENOEXEC;
       } else {
           error = ENOENT;         /* Nothing found */
       }
   
   out:
       return error;
   }
   
   
   linker_file_t
   linker_find_file_by_name(const char* filename)
   {
       linker_file_t lf = NULL;
       char *koname;
       int i;
   
       for (i = strlen(filename); i > 0 && filename[i-1] != '/'; --i)
           ;
       filename += i;
   
       koname = kmalloc(strlen(filename) + 4, M_LINKER, M_WAITOK);
       ksprintf(koname, "%s.ko", filename);
   
       lockmgr(&lock, LK_SHARED);
       TAILQ_FOREACH(lf, &linker_files, link) {
           if (!strcmp(lf->filename, koname))
               break;
           if (!strcmp(lf->filename, filename))
               break;
       }
       lockmgr(&lock, LK_RELEASE);
   
       if (koname)
           kfree(koname, M_LINKER);
       return lf;
   }
   
   linker_file_t
   linker_find_file_by_id(int fileid)
   {
       linker_file_t lf = NULL;
   
       lockmgr(&lock, LK_SHARED);
       TAILQ_FOREACH(lf, &linker_files, link)
           if (lf->id == fileid)
               break;
       lockmgr(&lock, LK_RELEASE);
   
       return lf;
   }
   
   int
   linker_file_foreach(linker_predicate_t *predicate, void *context)
   {
       linker_file_t lf;
       int retval = 0;
   
       lockmgr(&lock, LK_SHARED);
       TAILQ_FOREACH(lf, &linker_files, link) {
           retval = predicate(lf, context);
           if (retval != 0)
               break;
       }
       lockmgr(&lock, LK_RELEASE);
       return (retval);
   }
   
   linker_file_t
   linker_make_file(const char* pathname, void* priv, struct linker_file_ops* ops)
   {
       linker_file_t lf = NULL;
       const char *filename;
   
       filename = rindex(pathname, '/');
       if (filename && filename[1])
           filename++;
       else
           filename = pathname;
   
       KLD_DPF(FILE, ("linker_make_file: new file, filename=%s\n", filename));
       lockmgr(&lock, LK_EXCLUSIVE);
       lf = kmalloc(sizeof(struct linker_file), M_LINKER, M_WAITOK | M_ZERO);
       lf->refs = 1;
       lf->userrefs = 0;
       lf->flags = 0;
       lf->filename = linker_strdup(filename);
       lf->id = next_file_id++;
       lf->ndeps = 0;
       lf->deps = NULL;
       STAILQ_INIT(&lf->common);
       TAILQ_INIT(&lf->modules);
   
       lf->priv = priv;
       lf->ops = ops;
       TAILQ_INSERT_TAIL(&linker_files, lf, link);
   
       lockmgr(&lock, LK_RELEASE);
       return lf;
   }
   
   int
   linker_file_unload(linker_file_t file)
   {
       module_t mod, next;
       modlist_t ml, nextml;
       struct common_symbol* cp;
       int error = 0;
       int i;
   
       /* Refuse to unload modules if securelevel raised */
       if (securelevel > 0 || kernel_mem_readonly)
           return EPERM; 
   
       KLD_DPF(FILE, ("linker_file_unload: lf->refs=%d\n", file->refs));
   
       lockmgr(&lock, LK_EXCLUSIVE);
   
       /* Easy case of just dropping a reference. */
       if (file->refs > 1) {
               file->refs--;
               lockmgr(&lock, LK_RELEASE);
               return (0);
       }
   
       KLD_DPF(FILE, ("linker_file_unload: file is unloading, informing modules\n"));
   
       /*
        * Inform any modules associated with this file.
        */
       mod = TAILQ_FIRST(&file->modules);
       for (mod = TAILQ_FIRST(&file->modules); mod; mod = next) {
           next = module_getfnext(mod);
   
           /*
            * Give the module a chance to veto the unload.  Note that the
            * act of unloading the module may cause other modules in the
            * same file list to be unloaded recursively.
            */
           if ((error = module_unload(mod)) != 0) {
               KLD_DPF(FILE, ("linker_file_unload: module %p vetoes unload\n",
                              mod));
               lockmgr(&lock, LK_RELEASE);
               file->refs--;
               goto out;
           }
           module_release(mod);
       }
   
       TAILQ_FOREACH_MUTABLE(ml, &found_modules, link, nextml) {
           if (ml->container == file) {
               TAILQ_REMOVE(&found_modules, ml, link);
               kfree(ml, M_LINKER);
           }
       }
   
       /* Don't try to run SYSUNINITs if we are unloaded due to a link error */
       if (file->flags & LINKER_FILE_LINKED) {
           file->flags &= ~LINKER_FILE_LINKED;
           lockmgr(&lock, LK_RELEASE);
           linker_file_sysuninit(file);
           linker_file_unregister_sysctls(file);
           lockmgr(&lock, LK_EXCLUSIVE);
       }
   
       TAILQ_REMOVE(&linker_files, file, link);
   
       if (file->deps) {
           lockmgr(&lock, LK_RELEASE);
           for (i = 0; i < file->ndeps; i++)
               linker_file_unload(file->deps[i]);
           lockmgr(&lock, LK_EXCLUSIVE);
           kfree(file->deps, M_LINKER);
           file->deps = NULL;
       }
   
       while ((cp = STAILQ_FIRST(&file->common)) != NULL) {
           STAILQ_REMOVE_HEAD(&file->common, link);
           kfree(cp, M_LINKER);
       }
   
       file->ops->unload(file);
   
       if (file->filename) {
           kfree(file->filename, M_LINKER);
           file->filename = NULL;
       }
   
       kfree(file, M_LINKER);
   
       lockmgr(&lock, LK_RELEASE);
   
   out:
       return error;
   }
   
   void
   linker_file_add_dependancy(linker_file_t file, linker_file_t dep)
   {
       linker_file_t* newdeps;
   
       newdeps = kmalloc((file->ndeps + 1) * sizeof(linker_file_t*),
                        M_LINKER, M_WAITOK | M_ZERO);
   
       if (file->deps) {
           bcopy(file->deps, newdeps, file->ndeps * sizeof(linker_file_t*));
           kfree(file->deps, M_LINKER);
       }
       file->deps = newdeps;
       file->deps[file->ndeps] = dep;
       file->ndeps++;
   }
   
   /*
    * Locate a linker set and its contents.
    * This is a helper function to avoid linker_if.h exposure elsewhere.
    * Note: firstp and lastp are really void ***
    */
   int
   linker_file_lookup_set(linker_file_t file, const char *name,
                         void *firstp, void *lastp, int *countp)
   {
       return file->ops->lookup_set(file, name, firstp, lastp, countp);
   }
   
   int
   linker_file_lookup_symbol(linker_file_t file, const char* name, int deps, caddr_t *raddr)
   {
       c_linker_sym_t sym;
       linker_symval_t symval;
       linker_file_t lf;
       size_t common_size = 0;
       int i;
   
       KLD_DPF(SYM, ("linker_file_lookup_symbol: file=%p, name=%s, deps=%d\n",
                     file, name, deps));
   
       if (file->ops->lookup_symbol(file, name, &sym) == 0) {
           file->ops->symbol_values(file, sym, &symval);
   
           /*
            * XXX Assume a common symbol if its value is 0 and it has a non-zero
            * size, otherwise it could be an absolute symbol with a value of 0.
            */
           if (symval.value == NULL && symval.size != 0) {
               /*
                * For commons, first look them up in the dependancies and
                * only allocate space if not found there.
                */
               common_size = symval.size;
           } else {
               KLD_DPF(SYM, ("linker_file_lookup_symbol: symbol.value=%p\n", symval.value));
               *raddr = symval.value;
               return 0;
           }
       }
       if (deps) {
           for (i = 0; i < file->ndeps; i++) {
               if (linker_file_lookup_symbol(file->deps[i], name, 0, raddr) == 0) {
                   KLD_DPF(SYM, ("linker_file_lookup_symbol: deps value=%p\n", *raddr));
                   return 0;
               }
           }
   
           /* If we have not found it in the dependencies, search globally */
           TAILQ_FOREACH(lf, &linker_files, link) {
               /* But skip the current file if it's on the list */
               if (lf == file)
                   continue;
               /* And skip the files we searched above */
               for (i = 0; i < file->ndeps; i++)
                   if (lf == file->deps[i])
                       break;
               if (i < file->ndeps)
                   continue;
               if (linker_file_lookup_symbol(lf, name, 0, raddr) == 0) {
                   KLD_DPF(SYM, ("linker_file_lookup_symbol: global value=%p\n", *raddr));
                   return 0;
               }
           }
       }
   
       if (common_size > 0) {
           /*
            * This is a common symbol which was not found in the
            * dependancies.  We maintain a simple common symbol table in
            * the file object.
            */
           struct common_symbol* cp;
   
           STAILQ_FOREACH(cp, &file->common, link)
               if (!strcmp(cp->name, name)) {
                   KLD_DPF(SYM, ("linker_file_lookup_symbol: old common value=%p\n", cp->address));
                   *raddr = cp->address;
                   return 0;
               }
   
           /*
            * Round the symbol size up to align.
            */
           common_size = (common_size + sizeof(int) - 1) & -sizeof(int);
           cp = kmalloc(sizeof(struct common_symbol)
                       + common_size
                       + strlen(name) + 1,
                       M_LINKER, M_WAITOK | M_ZERO);
   
           cp->address = (caddr_t) (cp + 1);
           cp->name = cp->address + common_size;
           strcpy(cp->name, name);
           bzero(cp->address, common_size);
           STAILQ_INSERT_TAIL(&file->common, cp, link);
   
           KLD_DPF(SYM, ("linker_file_lookup_symbol: new common value=%p\n", cp->address));
           *raddr = cp->address;
           return 0;
       }
   
   #ifdef _KERNEL_VIRTUAL
       *raddr = dlsym(RTLD_NEXT, name);
       if (*raddr != NULL) {
           KLD_DPF(SYM, ("linker_file_lookup_symbol: found dlsym=%p\n", *raddr));
           return 0;
       }
   #endif
   
       KLD_DPF(SYM, ("linker_file_lookup_symbol: fail\n"));
       return ENOENT;
   }
   
   #ifdef DDB
   /*
    * DDB Helpers.  DDB has to look across multiple files with their own
    * symbol tables and string tables.
    *
    * Note that we do not obey list locking protocols here.  We really don't
    * need DDB to hang because somebody's got the lock held.  We'll take the
    * chance that the files list is inconsistant instead.
    */
   
   int
   linker_ddb_lookup(const char *symstr, c_linker_sym_t *sym)
   {
       linker_file_t lf;
   
       TAILQ_FOREACH(lf, &linker_files, link) {
           if (lf->ops->lookup_symbol(lf, symstr, sym) == 0)
               return 0;
       }
       return ENOENT;
   }
   
   int
   linker_ddb_search_symbol(caddr_t value, c_linker_sym_t *sym, long *diffp)
   {
       linker_file_t lf;
       u_long off = (uintptr_t)value;
       u_long diff, bestdiff;
       c_linker_sym_t best;
       c_linker_sym_t es;
   
       best = NULL;
       bestdiff = off;
       TAILQ_FOREACH(lf, &linker_files, link) {
           if (lf->ops->search_symbol(lf, value, &es, &diff) != 0)
               continue;
           if (es != NULL && diff < bestdiff) {
               best = es;
               bestdiff = diff;
           }
           if (bestdiff == 0)
               break;
       }
       if (best) {
           *sym = best;
           *diffp = bestdiff;
           return 0;
       } else {
           *sym = NULL;
           *diffp = off;
           return ENOENT;
       }
   }
   
   int
   linker_ddb_symbol_values(c_linker_sym_t sym, linker_symval_t *symval)
   {
       linker_file_t lf;
   
       TAILQ_FOREACH(lf, &linker_files, link) {
           if (lf->ops->symbol_values(lf, sym, symval) == 0)
               return 0;
       }
       return ENOENT;
   }
   
   #endif
   
   /*
    * Syscalls.
    *
    * MPALMOSTSAFE
    */
   int
   sys_kldload(struct kldload_args *uap)
   {
       struct thread *td = curthread;
       char *file;
       char *kldname, *modname;
       linker_file_t lf;
       int error = 0;
   
       uap->sysmsg_result = -1;
   
       if (securelevel > 0 || kernel_mem_readonly) /* redundant, but that's OK */
           return EPERM;
   
       if ((error = priv_check(td, PRIV_KLD_LOAD)) != 0)
           return error;
   
       file = kmalloc(MAXPATHLEN, M_TEMP, M_WAITOK);
       if ((error = copyinstr(uap->file, file, MAXPATHLEN, NULL)) != 0)
           goto out;
   
       /*
        * If file does not contain a qualified name or any dot in it
        * (kldname.ko, or kldname.ver.ko) treat it as an interface
        * name.
        */
       if (index(file, '/') || index(file, '.')) {
           kldname = file;
           modname = NULL;
       } else {
           kldname = NULL;
           modname = file;
       }
   
       get_mplock();
       error = linker_load_module(kldname, modname, NULL, NULL, &lf);
       rel_mplock();
       if (error)
           goto out;
   
       lf->userrefs++;
       uap->sysmsg_result = lf->id;
   
   out:
       if (file)
           kfree(file, M_TEMP);
       return error;
   }
   
   /*
    * MPALMOSTSAFE
    */
   int
   sys_kldunload(struct kldunload_args *uap)
   {
       struct thread *td = curthread;
       linker_file_t lf;
       int error = 0;
   
       if (securelevel > 0 || kernel_mem_readonly) /* redundant, but that's OK */
           return EPERM;
   
       if ((error = priv_check(td, PRIV_KLD_UNLOAD)) != 0)
           return error;
   
       get_mplock();
       lf = linker_find_file_by_id(uap->fileid);
       if (lf) {
           KLD_DPF(FILE, ("kldunload: lf->userrefs=%d\n", lf->userrefs));
           if (lf->userrefs == 0) {
               kprintf("linkerunload: attempt to unload file that was loaded by the kernel\n");
               error = EBUSY;
               goto out;
           }
           lf->userrefs--;
           error = linker_file_unload(lf);
           if (error)
               lf->userrefs++;
       } else {
           error = ENOENT;
       }
   out:
       rel_mplock();
       return error;
   }
   
   /*
    * MPALMOSTSAFE
    */
   int
   sys_kldfind(struct kldfind_args *uap)
   {
       char *filename = NULL, *modulename;
       linker_file_t lf;
       int error;
   
       uap->sysmsg_result = -1;
   
       filename = kmalloc(MAXPATHLEN, M_TEMP, M_WAITOK);
       if ((error = copyinstr(uap->file, filename, MAXPATHLEN, NULL)) != 0)
           goto out;
   
       modulename = rindex(filename, '/');
       if (modulename == NULL)
           modulename = filename;
   
       get_mplock();
       lf = linker_find_file_by_name(modulename);
       if (lf)
           uap->sysmsg_result = lf->id;
       else
           error = ENOENT;
       rel_mplock();
   
   out:
       if (filename)
           kfree(filename, M_TEMP);
       return error;
   }
   
   /*
    * MPALMOSTSAFE
    */
   int
   sys_kldnext(struct kldnext_args *uap)
   {
       linker_file_t lf;
       int error = 0;
   
       get_mplock();
       if (uap->fileid == 0) {
               lf = TAILQ_FIRST(&linker_files);
       } else {
               lf = linker_find_file_by_id(uap->fileid);
               if (lf == NULL) {
                       error = ENOENT;
                       goto out;
               }
               lf = TAILQ_NEXT(lf, link);
       }
   
       /* Skip partially loaded files. */
       while (lf != NULL && !(lf->flags & LINKER_FILE_LINKED)) {
               lf = TAILQ_NEXT(lf, link);
       }
   
       if (lf)
           uap->sysmsg_result = lf->id;
       else
           uap->sysmsg_result = 0;
   
   out:
       rel_mplock();
       return error;
   }
   
   /*
    * MPALMOSTSAFE
    */
   int
   sys_kldstat(struct kldstat_args *uap)
   {
       linker_file_t lf;
       int error = 0;
       int version;
       struct kld_file_stat* stat;
       int namelen;
   
       get_mplock();
       lf = linker_find_file_by_id(uap->fileid);
       if (!lf) {
           error = ENOENT;
           goto out;
       }
   
       stat = uap->stat;
   
       /*
        * Check the version of the user's structure.
        */
       if ((error = copyin(&stat->version, &version, sizeof(version))) != 0)
           goto out;
       if (version != sizeof(struct kld_file_stat)) {
           error = EINVAL;
           goto out;
       }
   
       namelen = strlen(lf->filename) + 1;
       if (namelen > MAXPATHLEN)
           namelen = MAXPATHLEN;
       if ((error = copyout(lf->filename, &stat->name[0], namelen)) != 0)
           goto out;
       if ((error = copyout(&lf->refs, &stat->refs, sizeof(int))) != 0)
           goto out;
       if ((error = copyout(&lf->id, &stat->id, sizeof(int))) != 0)
           goto out;
       if ((error = copyout(&lf->address, &stat->address, sizeof(caddr_t))) != 0)
           goto out;
       if ((error = copyout(&lf->size, &stat->size, sizeof(size_t))) != 0)
           goto out;
   
       uap->sysmsg_result = 0;
   
   out:
       rel_mplock();
       return error;
   }
   
   /*
    * MPALMOSTSAFE
    */
   int
   sys_kldfirstmod(struct kldfirstmod_args *uap)
   {
       linker_file_t lf;
       int error = 0;
   
       get_mplock();
       lf = linker_find_file_by_id(uap->fileid);
       if (lf) {
           if (TAILQ_FIRST(&lf->modules))
               uap->sysmsg_result = module_getid(TAILQ_FIRST(&lf->modules));
           else
               uap->sysmsg_result = 0;
       } else {
           error = ENOENT;
       }
       rel_mplock();
   
       return error;
   }
   
   /*
    * MPALMOSTSAFE
    */
   int
   sys_kldsym(struct kldsym_args *uap)
  {
      char *symstr = NULL;
      c_linker_sym_t sym;
      linker_symval_t symval;
      linker_file_t lf;
      struct kld_sym_lookup lookup;
      int error = 0;
  
      get_mplock();
      if ((error = copyin(uap->data, &lookup, sizeof(lookup))) != 0)
          goto out;
      if (lookup.version != sizeof(lookup) || uap->cmd != KLDSYM_LOOKUP) {
          error = EINVAL;
          goto out;
      }
  
      symstr = kmalloc(MAXPATHLEN, M_TEMP, M_WAITOK);
      if ((error = copyinstr(lookup.symname, symstr, MAXPATHLEN, NULL)) != 0)
          goto out;
  
      if (uap->fileid != 0) {
          lf = linker_find_file_by_id(uap->fileid);
          if (lf == NULL) {
              error = ENOENT;
              goto out;
          }
          if (lf->ops->lookup_symbol(lf, symstr, &sym) == 0 &&
              lf->ops->symbol_values(lf, sym, &symval) == 0) {
              lookup.symvalue = (uintptr_t)symval.value;
              lookup.symsize = symval.size;
              error = copyout(&lookup, uap->data, sizeof(lookup));
          } else
              error = ENOENT;
      } else {
          TAILQ_FOREACH(lf, &linker_files, link) {
              if (lf->ops->lookup_symbol(lf, symstr, &sym) == 0 &&
                  lf->ops->symbol_values(lf, sym, &symval) == 0) {
                  lookup.symvalue = (uintptr_t)symval.value;
                  lookup.symsize = symval.size;
                  error = copyout(&lookup, uap->data, sizeof(lookup));
                  break;
              }
          }
          if (!lf)
              error = ENOENT;
      }
  out:
      rel_mplock();
      if (symstr)
          kfree(symstr, M_TEMP);
      return error;
  }
  
  /*
   * Preloaded module support
   */
  
  static modlist_t
  modlist_lookup(const char *name, int ver)
  {
      modlist_t       mod;
  
      TAILQ_FOREACH(mod, &found_modules, link) {
          if (strcmp(mod->name, name) == 0 && (ver == 0 || mod->version == ver))
              return (mod);
      }
      return (NULL);
  }
  
  static modlist_t
  modlist_lookup2(const char *name, struct mod_depend *verinfo)
  {
      modlist_t       mod, bestmod;
      int             ver;
  
      if (verinfo == NULL)
          return (modlist_lookup(name, 0));
      bestmod = NULL;
      TAILQ_FOREACH(mod, &found_modules, link) {
          if (strcmp(mod->name, name) != 0)
              continue;
          ver = mod->version;
          if (ver == verinfo->md_ver_preferred)
              return (mod);
          if (ver >= verinfo->md_ver_minimum &&
                  ver <= verinfo->md_ver_maximum &&
                  (bestmod == NULL || ver > bestmod->version))
              bestmod = mod;
      }
      return (bestmod);
  }
  
  int
  linker_reference_module(const char *modname, struct mod_depend *verinfo,
      linker_file_t *result)
  {
      modlist_t mod;
      int error;
  
      lockmgr(&lock, LK_SHARED);
      if ((mod = modlist_lookup2(modname, verinfo)) != NULL) {
          *result = mod->container;
          (*result)->refs++;
          lockmgr(&lock, LK_RELEASE);
          return (0);
      }
  
      lockmgr(&lock, LK_RELEASE);
      get_mplock();
      error = linker_load_module(NULL, modname, NULL, verinfo, result);
      rel_mplock();
      return (error);
  }
  
  int
  linker_release_module(const char *modname, struct mod_depend *verinfo,
      linker_file_t lf)
  {
      modlist_t mod;
      int error;
  
      lockmgr(&lock, LK_SHARED);
      if (lf == NULL) {
          KASSERT(modname != NULL,
              ("linker_release_module: no file or name"));
          mod = modlist_lookup2(modname, verinfo);
          if (mod == NULL) {
              lockmgr(&lock, LK_RELEASE);
              return (ESRCH);
          }
          lf = mod->container;
      } else
          KASSERT(modname == NULL && verinfo == NULL,
              ("linker_release_module: both file and name"));
      lockmgr(&lock, LK_RELEASE);
      get_mplock();
      error = linker_file_unload(lf);
      rel_mplock();
      return (error);
  }
  
  static modlist_t
  modlist_newmodule(const char *modname, int version, linker_file_t container)
  {
      modlist_t       mod;
  
      mod = kmalloc(sizeof(struct modlist), M_LINKER, M_NOWAIT | M_ZERO);
      if (mod == NULL)
          panic("no memory for module list");
      mod->container = container;
      mod->name = modname;
      mod->version = version;
      TAILQ_INSERT_TAIL(&found_modules, mod, link);
      return (mod);
  }
  
  static void
  linker_addmodules(linker_file_t lf, struct mod_metadata **start,
                    struct mod_metadata **stop, int preload)
  {
      struct mod_metadata *mp, **mdp;
      const char     *modname;
      int             ver;
  
      for (mdp = start; mdp < stop; mdp++) {
          mp = *mdp;
          if (mp->md_type != MDT_VERSION)
              continue;
          modname = mp->md_cval;
          ver = ((struct mod_version *)mp->md_data)->mv_version;
          if (modlist_lookup(modname, ver) != NULL) {
              kprintf("module %s already present!\n", modname);
              /* XXX what can we do? this is a build error. :-( */
              continue;
          }
          modlist_newmodule(modname, ver, lf);
      }
  }
  
  static void
  linker_preload(void* arg)
  {
      caddr_t             modptr;
      const char          *modname, *nmodname;
      char                *modtype;
      linker_file_t       lf, nlf;
      linker_class_t      lc;
      int                 error;
      linker_file_list_t loaded_files;
      linker_file_list_t depended_files;
      struct mod_metadata *mp, *nmp;
      struct mod_metadata **start, **stop, **mdp, **nmdp;
      struct mod_depend *verinfo;
      int nver;
      int resolves;
      modlist_t mod;
      struct sysinit      **si_start, **si_stop;
  
      TAILQ_INIT(&loaded_files);
      TAILQ_INIT(&depended_files);
      TAILQ_INIT(&found_modules);
  
      modptr = NULL;
      while ((modptr = preload_search_next_name(modptr)) != NULL) {
          modname = (char *)preload_search_info(modptr, MODINFO_NAME);
          modtype = (char *)preload_search_info(modptr, MODINFO_TYPE);
          if (modname == NULL) {
              kprintf("Preloaded module at %p does not have a name!\n", modptr);
              continue;
          }
          if (modtype == NULL) {
              kprintf("Preloaded module at %p does not have a type!\n", modptr);
              continue;
          }
  
          if (bootverbose)
                  kprintf("Preloaded %s \"%s\" at %p.\n", modtype, modname, modptr);
          lf = NULL;
          TAILQ_FOREACH(lc, &classes, link) {
              error = lc->ops->preload_file(modname, &lf);
              if (!error)
                  break;
              lf = NULL;
          }
          if (lf)
                  TAILQ_INSERT_TAIL(&loaded_files, lf, loaded);
      }
  
      /*
       * First get a list of stuff in the kernel.
       */
      if (linker_file_lookup_set(linker_kernel_file, MDT_SETNAME, &start,
                                 &stop, NULL) == 0)
          linker_addmodules(linker_kernel_file, start, stop, 1);
  
      /*
       * This is a once-off kinky bubble sort to resolve relocation
       * dependency requirements.
       */
  restart:
      TAILQ_FOREACH(lf, &loaded_files, loaded) {
          error = linker_file_lookup_set(lf, MDT_SETNAME, &start, &stop, NULL);
          /*
           * First, look to see if we would successfully link with this
           * stuff.
           */
          resolves = 1;           /* unless we know otherwise */
          if (!error) {
              for (mdp = start; mdp < stop; mdp++) {
                  mp = *mdp;
                  if (mp->md_type != MDT_DEPEND)
                      continue;
                  modname = mp->md_cval;
                  verinfo = mp->md_data;
                  for (nmdp = start; nmdp < stop; nmdp++) {
                      nmp = *nmdp;
                      if (nmp->md_type != MDT_VERSION)
                          continue;
                      nmodname = nmp->md_cval;
                      if (strcmp(modname, nmodname) == 0)
                          break;
                  }
                  if (nmdp < stop)/* it's a self reference */
                      continue;
  
                  /*
                   * ok, the module isn't here yet, we
                   * are not finished
                   */
                  if (modlist_lookup2(modname, verinfo) == NULL)
                      resolves = 0;
              }
          }
          /*
           * OK, if we found our modules, we can link.  So, "provide"
           * the modules inside and add it to the end of the link order
           * list.
           */
          if (resolves) {
              if (!error) {
                  for (mdp = start; mdp < stop; mdp++) {
                      mp = *mdp;
                      if (mp->md_type != MDT_VERSION)
                          continue;
                      modname = mp->md_cval;
                      nver = ((struct mod_version *)mp->md_data)->mv_version;
                      if (modlist_lookup(modname, nver) != NULL) {
                          kprintf("module %s already present!\n", modname);
                          TAILQ_REMOVE(&loaded_files, lf, loaded);
                          linker_file_unload(lf /* , LINKER_UNLOAD_FORCE */ );
                          /* we changed tailq next ptr */
                          goto restart;
                      }
                      modlist_newmodule(modname, nver, lf);
                  }
              }
              TAILQ_REMOVE(&loaded_files, lf, loaded);
              TAILQ_INSERT_TAIL(&depended_files, lf, loaded);
              /*
               * Since we provided modules, we need to restart the
               * sort so that the previous files that depend on us
               * have a chance. Also, we've busted the tailq next
               * pointer with the REMOVE.
               */
              goto restart;
          }
      }
  
      /*
       * At this point, we check to see what could not be resolved..
       */
      while ((lf = TAILQ_FIRST(&loaded_files)) != NULL) {
          TAILQ_REMOVE(&loaded_files, lf, loaded);
          kprintf("KLD file %s is missing dependencies\n", lf->filename);
          linker_file_unload(lf /* , LINKER_UNLOAD_FORCE */ );
      }
  
      /*
       * We made it. Finish off the linking in the order we determined.
       */
      TAILQ_FOREACH_MUTABLE(lf, &depended_files, loaded, nlf) {
          if (linker_kernel_file) {
              linker_kernel_file->refs++;
              linker_file_add_dependancy(lf, linker_kernel_file);
          }
          lf->userrefs++;
  
          error = linker_file_lookup_set(lf, MDT_SETNAME, &start, &stop, NULL);
          if (!error) {
              for (mdp = start; mdp < stop; mdp++) {
                  mp = *mdp;
                  if (mp->md_type != MDT_DEPEND)
                      continue;
                  modname = mp->md_cval;
                  verinfo = mp->md_data;
                  mod = modlist_lookup2(modname, verinfo);
                  /* Don't count self-dependencies */
                  if (lf == mod->container)
                      continue;
                  mod->container->refs++;
                  linker_file_add_dependancy(lf, mod->container);
              }
          }
          /*
           * Now do relocation etc using the symbol search paths
           * established by the dependencies
           */
          error = lf->ops->preload_finish(lf);
          if (error) {
              TAILQ_REMOVE(&depended_files, lf, loaded);
              kprintf("KLD file %s - could not finalize loading\n",
                      lf->filename);
              linker_file_unload(lf /* , LINKER_UNLOAD_FORCE */);
              continue;
          }
          linker_file_register_modules(lf);
          if (linker_file_lookup_set(lf, "sysinit_set", &si_start, &si_stop, NULL) == 0)
              sysinit_add(si_start, si_stop);
          linker_file_register_sysctls(lf);
          lf->flags |= LINKER_FILE_LINKED;
      }
      /* woohoo! we made it! */
  }
  
  SYSINIT(preload, SI_BOOT2_KLD, SI_ORDER_MIDDLE, linker_preload, 0);
  
  /*
   * Search for a not-loaded module by name.
   *
   * Modules may be found in the following locations:
   *
   * - preloaded (result is just the module name)
   * - on disk (result is full path to module)
   *
   * If the module name is qualified in any way (contains path, etc.)
   * the we simply return a copy of it.
   *
   * The search path can be manipulated via sysctl.  Note that we use the ';'
   * character as a separator to be consistent with the bootloader.
   */
  
  static char linker_path[MAXPATHLEN] = "/boot;/boot/modules;/;/modules";
  
  SYSCTL_STRING(_kern, OID_AUTO, module_path, CTLFLAG_RW, linker_path,
                sizeof(linker_path), "module load search path");
  TUNABLE_STR("module_path", linker_path, sizeof(linker_path));
  
  char *
  linker_search_path(const char *name)
  {
      struct nlookupdata  nd;
      char                *cp, *ep, *result;
      size_t              name_len, prefix_len;
      size_t              result_len;
      int                 sep;
      int                 error;
      enum vtype          type;
      const char *exts[] = { "", ".ko", NULL };
      const char **ext;
  
      /* qualified at all? */
      if (index(name, '/'))
          return(linker_strdup(name));
  
      /* traverse the linker path */
      cp = linker_path;
      name_len = strlen(name);
      for (;;) {
  
          /* find the end of this component */
          for (ep = cp; (*ep != 0) && (*ep != ';'); ep++)
              ;
          prefix_len = ep - cp;
          /* if this component doesn't end with a slash, add one */
          if (ep == cp || *(ep - 1) != '/')
              sep = 1;
          else
              sep = 0;
  
          /*
           * +2+3 : possible separator, plus terminator + possible extension.
           */
          result = kmalloc(prefix_len + name_len + 2+3, M_LINKER, M_WAITOK);
  
          strncpy(result, cp, prefix_len);
          if (sep)
              result[prefix_len++] = '/';
          strcpy(result + prefix_len, name);
  
          result_len = strlen(result);
          for (ext = exts; *ext != NULL; ext++) {
              strcpy(result + result_len, *ext);
  
              /*
               * Attempt to open the file, and return the path if we succeed and it's
               * a regular file.
               */
              error = nlookup_init(&nd, result, UIO_SYSSPACE, NLC_FOLLOW|NLC_LOCKVP);
              if (error == 0)
                  error = vn_open(&nd, NULL, FREAD, 0);
              if (error == 0) {
                  type = nd.nl_open_vp->v_type;
                  if (type == VREG) {
                      nlookup_done(&nd);
                      return (result);
                  }
              }
              nlookup_done(&nd);
          }
  
          kfree(result, M_LINKER);
  
          if (*ep == 0)
              break;
          cp = ep + 1;
      }
      return(NULL);
  }
  
  /*
   * Find a file which contains given module and load it, if "parent" is not
   * NULL, register a reference to it.
   */
  static int
  linker_load_module(const char *kldname, const char *modname,
                     struct linker_file *parent, struct mod_depend *verinfo,
                     struct linker_file **lfpp)
  {
      linker_file_t   lfdep;
      const char     *filename;
      char           *pathname;
      int             error;
  
      if (modname == NULL) {
          /*
           * We have to load KLD
           */
          KASSERT(verinfo == NULL, ("linker_load_module: verinfo is not NULL"));
          pathname = linker_search_path(kldname);
      } else {
          if (modlist_lookup2(modname, verinfo) != NULL)
              return (EEXIST);
          if (kldname != NULL)
          {
              pathname = linker_strdup(kldname);
          }
          else if (rootvnode == NULL)
              pathname = NULL;
          else
          {
              pathname = linker_search_path(modname);
          }
  #if 0
          /*
           * Need to find a KLD with required module
           */
          pathname = linker_search_module(modname,
                                          strlen(modname), verinfo);
  #endif
      }
      if (pathname == NULL)
          return (ENOENT);
  
      /*
       * Can't load more than one file with the same basename XXX:
       * Actually it should be possible to have multiple KLDs with
       * the same basename but different path because they can
       * provide different versions of the same modules.
       */
      filename = rindex(pathname, '/');
      if (filename == NULL)
          filename = filename;
      else
          filename++;
      if (linker_find_file_by_name(filename))
          error = EEXIST;
      else
          do {
              error = linker_load_file(pathname, &lfdep);
              if (error)
                  break;
              if (modname && verinfo && modlist_lookup2(modname, verinfo) == NULL) {
                  linker_file_unload(lfdep /* , LINKER_UNLOAD_FORCE */ );
                  error = ENOENT;
                  break;
              }
              if (parent) {
                  linker_file_add_dependancy(parent, lfdep);
              }
              if (lfpp)
                  *lfpp = lfdep;
          } while (0);
      kfree(pathname, M_LINKER);
      return (error);
  }
  
  /*
   * This routine is responsible for finding dependencies of userland initiated
   * kldload(2)'s of files.
   */
  int
  linker_load_dependencies(linker_file_t lf)
  {
      linker_file_t   lfdep;
      struct mod_metadata **start, **stop, **mdp, **nmdp;
      struct mod_metadata *mp, *nmp;
      struct mod_depend *verinfo;
      modlist_t       mod;
      const char     *modname, *nmodname;
      int             ver, error = 0, count;
  
      /*
       * All files are dependant on /kernel.
       */
      if (linker_kernel_file) {
          linker_kernel_file->refs++;
          linker_file_add_dependancy(lf, linker_kernel_file);
      }
      if (linker_file_lookup_set(lf, MDT_SETNAME, &start, &stop, &count) != 0)
          return (0);
      for (mdp = start; mdp < stop; mdp++) {
          mp = *mdp;
          if (mp->md_type != MDT_VERSION)
              continue;
          modname = mp->md_cval;
          ver = ((struct mod_version *)mp->md_data)->mv_version;
          mod = modlist_lookup(modname, ver);
          if (mod != NULL) {
              kprintf("interface %s.%d already present in the KLD '%s'!\n",
                      modname, ver, mod->container->filename);
              return (EEXIST);
          }
      }
  
      for (mdp = start; mdp < stop; mdp++) {
          mp = *mdp;
          if (mp->md_type != MDT_DEPEND)
              continue;
          modname = mp->md_cval;
          verinfo = mp->md_data;
          nmodname = NULL;
          for (nmdp = start; nmdp < stop; nmdp++) {
              nmp = *nmdp;
              if (nmp->md_type != MDT_VERSION)
                  continue;
              nmodname = nmp->md_cval;
              if (strcmp(modname, nmodname) == 0)
                  break;
          }
          if (nmdp < stop)        /* early exit, it's a self reference */
              continue;
          mod = modlist_lookup2(modname, verinfo);
          if (mod) {              /* woohoo, it's loaded already */
              lfdep = mod->container;
              lfdep->refs++;
              linker_file_add_dependancy(lf, lfdep);
              continue;
          }
          error = linker_load_module(NULL, modname, lf, verinfo, NULL);
          if (error) {
              kprintf("KLD %s: depends on %s - not available or version mismatch\n",
                      lf->filename, modname);
              break;
          }
      }
  
      if (error)
          return (error);
      linker_addmodules(lf, start, stop, 0);
      return (error);
  }

Cache object: a3375f390d06d16cf004629794ef8e89