FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_module.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_module.c,v 1.21 1999/11/08 06:53:30 peter Exp $
     * $DragonFly: src/sys/kern/kern_module.c,v 1.16 2008/06/07 11:44:04 mneumann Exp $
     */
    
    #include <sys/param.h>
    #include <sys/kernel.h>
    #include <sys/systm.h>
    #include <sys/eventhandler.h>
    #include <sys/malloc.h>
    #include <sys/sysproto.h>
    #include <sys/sysent.h>
    #include <sys/module.h>
    #include <sys/linker.h>
    #include <sys/proc.h>
    
    #include <sys/mplock2.h>
    
    MALLOC_DEFINE(M_MODULE, "module", "module data structures");
    
    typedef TAILQ_HEAD(, module) modulelist_t;
    struct module {
        TAILQ_ENTRY(module) link;           /* chain together all modules */
        TAILQ_ENTRY(module) flink;          /* all modules in a file */
        struct linker_file* file;           /* file which contains this module */
        int                 refs;           /* reference count */
        int                 id;             /* unique id number */
        char                *name;          /* module name */
        modeventhand_t      handler;        /* event handler */
        void                *arg;           /* argument for handler */
        modspecific_t       data;           /* module specific data */
    };
    
    #define MOD_EVENT(mod, type) (mod)->handler((mod), (type), (mod)->arg)
    
    static modulelist_t modules = TAILQ_HEAD_INITIALIZER(modules);
    static int nextid = 1;
    
    static void module_shutdown(void*, int);
    
    static int
    modevent_nop(module_t mod, int what, void* arg)
    {
            return 0;
    }
    
    
    static void
    module_init(void* arg)
    {
        TAILQ_INIT(&modules);
        EVENTHANDLER_REGISTER(shutdown_post_sync, module_shutdown, NULL,
                              SHUTDOWN_PRI_DEFAULT);
    }
    
    SYSINIT(module, SI_BOOT2_KLD, SI_ORDER_FIRST, module_init, 0);
    
    static void
    module_shutdown(void* arg1, int arg2)
    {
        module_t mod;
    
        for (mod = TAILQ_FIRST(&modules); mod; mod = TAILQ_NEXT(mod, link))
            MOD_EVENT(mod, MOD_SHUTDOWN);
    }
    
    void
    module_register_init(const void *arg)
    {
        const moduledata_t* data = (const moduledata_t*) arg;
        int error;
        module_t mod;
    
        mod = module_lookupbyname(data->name);
        if (mod == NULL) {
   #if 0
           panic("module_register_init: module named %s not found", data->name);
   #else
           /* temporary kludge until kernel `file' attachment registers modules */
           error = module_register(data, linker_kernel_file);
           if (error)
               panic("module_register_init: register of module failed! %d", error);
           mod = module_lookupbyname(data->name);
           if (mod == NULL)
               panic("module_register_init: module STILL not found!");
   #endif
       }
       error = MOD_EVENT(mod, MOD_LOAD);
       if (error) {
           module_unload(mod);     /* ignore error */
           module_release(mod);
           kprintf("module_register_init: MOD_LOAD (%s, %lx, %p) error %d\n",
                  data->name, (u_long)(uintfptr_t)data->evhand, data->priv, error);
       }
   }
   
   int
   module_register(const moduledata_t *data, linker_file_t container)
   {
       size_t namelen;
       module_t newmod;
   
       newmod = module_lookupbyname(data->name);
       if (newmod != NULL) {
           kprintf("module_register: module %s already exists!\n", data->name);
           return EEXIST;
       }
       namelen = strlen(data->name) + 1;
       newmod = (module_t) kmalloc(sizeof(struct module) + namelen,
                                  M_MODULE, M_WAITOK);
   
       newmod->refs = 1;
       newmod->id = nextid++;
       newmod->name = (char *) (newmod + 1);
       strcpy(newmod->name, data->name);
       newmod->handler = data->evhand ? data->evhand : modevent_nop;
       newmod->arg = data->priv;
       bzero(&newmod->data, sizeof(newmod->data));
       TAILQ_INSERT_TAIL(&modules, newmod, link);
   
       if (container == NULL)
           container = linker_current_file;
       if (container)
           TAILQ_INSERT_TAIL(&container->modules, newmod, flink);
       newmod->file = container;
   
       return 0;
   }
   
   void
   module_reference(module_t mod)
   {
       MOD_DPF(REFS, ("module_reference: before, refs=%d\n", mod->refs));
   
       mod->refs++;
   }
   
   /*
    * module_release()
    *
    *      Release ref on the module and return the new reference count.  If 0
    *      is returned, the module has been removed from its list and freed.
    */
   int
   module_release(module_t mod)
   {
       int rc;
   
       if (mod->refs <= 0)
           panic("module_release: bad reference count");
   
       MOD_DPF(REFS, ("module_release: before, refs=%d\n", mod->refs));
   
       rc = --mod->refs;
       if (rc == 0) {
           TAILQ_REMOVE(&modules, mod, link);
           if (mod->file) {
               TAILQ_REMOVE(&mod->file->modules, mod, flink);
           }
           kfree(mod, M_MODULE);
       }
       return(rc);
   }
   
   module_t
   module_lookupbyname(const char* name)
   {
       module_t mod;
   
       for (mod = TAILQ_FIRST(&modules); mod; mod = TAILQ_NEXT(mod, link)) {
           if (!strcmp(mod->name, name))
               return mod;
       }
   
       return NULL;
   }
   
   module_t
   module_lookupbyid(int modid)
   {
       module_t mod;
   
       for (mod = TAILQ_FIRST(&modules); mod; mod = TAILQ_NEXT(mod, link)) {
           if (mod->id == modid)
               return mod;
       }
   
       return NULL;
   }
   
   int
   module_unload(module_t mod)
   {
       int error;
   
       error = MOD_EVENT(mod, MOD_UNLOAD);
       /*sync_devs();*/
       return (error);
   }
   
   int
   module_getid(module_t mod)
   {
       return mod->id;
   }
   
   module_t
   module_getfnext(module_t mod)
   {
       return TAILQ_NEXT(mod, flink);
   }
   
   void
   module_setspecific(module_t mod, modspecific_t *datap)
   {
       mod->data = *datap;
   }
   
   /*
    * Syscalls.
    *
    * MPALMOSTSAFE
    */
   int
   sys_modnext(struct modnext_args *uap)
   {
       module_t mod;
       int error;
   
       get_mplock();
       uap->sysmsg_result = -1;
       if (uap->modid == 0) {
           mod = TAILQ_FIRST(&modules);
           if (mod) {
               uap->sysmsg_result = mod->id;
               error = 0;
               goto done;
           } else {
               error = ENOENT;
               goto done;
           }
       }
   
       mod = module_lookupbyid(uap->modid);
       if (!mod) {
           error = ENOENT;
           goto done;
       }
   
       if (TAILQ_NEXT(mod, link))
           uap->sysmsg_result = TAILQ_NEXT(mod, link)->id;
       else
           uap->sysmsg_result = 0;
       error = 0;
   done:
       rel_mplock();
       return error;
   }
   
   /*
    * MPALMOSTSAFE
    */
   int
   sys_modfnext(struct modfnext_args *uap)
   {
       module_t mod;
       int error;
   
       get_mplock();
       uap->sysmsg_result = -1;
   
       mod = module_lookupbyid(uap->modid);
       if (!mod) {
           error = ENOENT;
           goto done;
       }
   
       if (TAILQ_NEXT(mod, flink))
           uap->sysmsg_result = TAILQ_NEXT(mod, flink)->id;
       else
           uap->sysmsg_result = 0;
       error = 0;
   done:
       rel_mplock();
       return error;
   }
   
   struct module_stat_v1 {
       int         version;        /* set to sizeof(struct module_stat) */
       char        name[MAXMODNAME];
       int         refs;
       int         id;
   };
   
   /*
    * MPALMOSTSAFE
    */
   int
   sys_modstat(struct modstat_args *uap)
   {
       module_t mod;
       int error;
       int namelen;
       int version;
       struct module_stat* stat;
   
       get_mplock();
       mod = module_lookupbyid(uap->modid);
       if (!mod) {
           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 module_stat_v1)
           && version != sizeof(struct module_stat)) {
           error = EINVAL;
           goto out;
       }
   
       namelen = strlen(mod->name) + 1;
       if (namelen > MAXMODNAME)
           namelen = MAXMODNAME;
       if ((error = copyout(mod->name, &stat->name[0], namelen)) != 0)
           goto out;
   
       if ((error = copyout(&mod->refs, &stat->refs, sizeof(int))) != 0)
           goto out;
       if ((error = copyout(&mod->id, &stat->id, sizeof(int))) != 0)
           goto out;
   
       /*
        * >v1 stat includes module data.
        */
       if (version == sizeof(struct module_stat)) {
           if ((error = copyout(&mod->data, &stat->data, sizeof(mod->data))) != 0)
               goto out;
       }
   
       uap->sysmsg_result = 0;
   
   out:
       rel_mplock();
       return error;
   }
   
   /*
    * MPALMOSTSAFE
    */
   int
   sys_modfind(struct modfind_args *uap)
   {
       int error;
       char name[MAXMODNAME];
       module_t mod;
   
       get_mplock();
       if ((error = copyinstr(uap->name, name, sizeof name, 0)) != 0)
           goto out;
   
       mod = module_lookupbyname(name);
       if (!mod)
           error = ENOENT;
       else
           uap->sysmsg_result = mod->id;
   
   out:
       rel_mplock();
       return error;
   }

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