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9b3851e9e3
all the global bits of ``module'' data. This commit adds a few generic macros, MOD_SLOCK, MOD_XLOCK, etc., that are meant to be used as ways of accessing the SX lock. It is also the first step in helping to lock down the kernel linker and module systems. Reviewed by: jhb, jake, smp@
411 lines
8.4 KiB
C
411 lines
8.4 KiB
C
/*-
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* Copyright (c) 1997 Doug Rabson
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/systm.h>
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#include <sys/eventhandler.h>
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#include <sys/malloc.h>
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#include <sys/sysproto.h>
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#include <sys/sysent.h>
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#include <sys/proc.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/sx.h>
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#include <sys/module.h>
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#include <sys/linker.h>
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static MALLOC_DEFINE(M_MODULE, "module", "module data structures");
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typedef TAILQ_HEAD(, module) modulelist_t;
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struct module {
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TAILQ_ENTRY(module) link; /* chain together all modules */
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TAILQ_ENTRY(module) flink; /* all modules in a file */
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struct linker_file *file; /* file which contains this module */
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int refs; /* reference count */
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int id; /* unique id number */
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char *name; /* module name */
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modeventhand_t handler; /* event handler */
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void *arg; /* argument for handler */
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modspecific_t data; /* module specific data */
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};
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#define MOD_EVENT(mod, type) (mod)->handler((mod), (type), (mod)->arg)
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static modulelist_t modules;
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struct sx modules_sx;
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static int nextid = 1;
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static void module_shutdown(void *, int);
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static int
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modevent_nop(module_t mod, int what, void *arg)
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{
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return (0);
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}
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static void
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module_init(void *arg)
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{
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sx_init(&modules_sx, "module subsystem sx lock");
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TAILQ_INIT(&modules);
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EVENTHANDLER_REGISTER(shutdown_post_sync, module_shutdown, NULL,
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SHUTDOWN_PRI_DEFAULT);
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}
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SYSINIT(module, SI_SUB_KLD, SI_ORDER_FIRST, module_init, 0)
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static void
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module_shutdown(void *arg1, int arg2)
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{
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module_t mod;
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MOD_SLOCK;
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TAILQ_FOREACH(mod, &modules, link)
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MOD_EVENT(mod, MOD_SHUTDOWN);
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MOD_SUNLOCK;
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}
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void
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module_register_init(const void *arg)
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{
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const moduledata_t *data = (const moduledata_t *)arg;
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int error;
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module_t mod;
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MOD_SLOCK;
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mod = module_lookupbyname(data->name);
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if (mod == NULL)
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panic("module_register_init: module named %s not found\n",
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data->name);
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MOD_SUNLOCK;
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error = MOD_EVENT(mod, MOD_LOAD);
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if (error) {
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MOD_EVENT(mod, MOD_UNLOAD);
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MOD_XLOCK;
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module_release(mod);
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MOD_XUNLOCK;
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printf("module_register_init: MOD_LOAD (%s, %p, %p) error"
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" %d\n", data->name, (void *)data->evhand, data->priv,
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error);
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}
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}
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int
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module_register(const moduledata_t *data, linker_file_t container)
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{
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size_t namelen;
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module_t newmod;
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MOD_SLOCK;
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newmod = module_lookupbyname(data->name);
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if (newmod != NULL) {
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MOD_SUNLOCK;
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printf("module_register: module %s already exists!\n",
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data->name);
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return (EEXIST);
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}
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MOD_SUNLOCK;
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namelen = strlen(data->name) + 1;
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newmod = malloc(sizeof(struct module) + namelen, M_MODULE, M_WAITOK);
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if (newmod == NULL)
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return (ENOMEM);
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MOD_XLOCK;
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newmod->refs = 1;
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newmod->id = nextid++;
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newmod->name = (char *)(newmod + 1);
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strcpy(newmod->name, data->name);
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newmod->handler = data->evhand ? data->evhand : modevent_nop;
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newmod->arg = data->priv;
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bzero(&newmod->data, sizeof(newmod->data));
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TAILQ_INSERT_TAIL(&modules, newmod, link);
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if (container)
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TAILQ_INSERT_TAIL(&container->modules, newmod, flink);
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newmod->file = container;
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MOD_XUNLOCK;
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return (0);
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}
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void
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module_reference(module_t mod)
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{
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MOD_XLOCK_ASSERT;
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MOD_DPF(REFS, ("module_reference: before, refs=%d\n", mod->refs));
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mod->refs++;
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}
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void
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module_release(module_t mod)
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{
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MOD_XLOCK_ASSERT;
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if (mod->refs <= 0)
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panic("module_release: bad reference count");
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MOD_DPF(REFS, ("module_release: before, refs=%d\n", mod->refs));
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mod->refs--;
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if (mod->refs == 0) {
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TAILQ_REMOVE(&modules, mod, link);
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if (mod->file)
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TAILQ_REMOVE(&mod->file->modules, mod, flink);
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MOD_XUNLOCK;
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free(mod, M_MODULE);
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MOD_XLOCK;
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}
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}
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module_t
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module_lookupbyname(const char *name)
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{
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module_t mod;
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int err;
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MOD_LOCK_ASSERT;
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TAILQ_FOREACH(mod, &modules, link) {
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err = strcmp(mod->name, name);
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if (err == 0)
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return (mod);
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}
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return (NULL);
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}
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module_t
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module_lookupbyid(int modid)
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{
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module_t mod;
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MOD_LOCK_ASSERT;
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TAILQ_FOREACH(mod, &modules, link)
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if (mod->id == modid)
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return(mod);
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return (NULL);
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}
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int
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module_unload(module_t mod)
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{
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return (MOD_EVENT(mod, MOD_UNLOAD));
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}
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int
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module_getid(module_t mod)
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{
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MOD_LOCK_ASSERT;
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return (mod->id);
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}
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module_t
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module_getfnext(module_t mod)
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{
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MOD_LOCK_ASSERT;
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return (TAILQ_NEXT(mod, flink));
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}
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void
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module_setspecific(module_t mod, modspecific_t *datap)
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{
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MOD_XLOCK_ASSERT;
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mod->data = *datap;
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}
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/*
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* Syscalls.
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*/
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/*
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* MPSAFE
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*/
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int
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modnext(struct thread *td, struct modnext_args *uap)
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{
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module_t mod;
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int error = 0;
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mtx_lock(&Giant);
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td->td_retval[0] = -1;
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MOD_SLOCK;
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if (SCARG(uap, modid) == 0) {
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mod = TAILQ_FIRST(&modules);
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if (mod)
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td->td_retval[0] = mod->id;
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else
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error = ENOENT;
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goto done2;
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}
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mod = module_lookupbyid(SCARG(uap, modid));
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if (mod == NULL) {
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error = ENOENT;
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goto done2;
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}
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if (TAILQ_NEXT(mod, link))
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td->td_retval[0] = TAILQ_NEXT(mod, link)->id;
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else
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td->td_retval[0] = 0;
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done2:
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MOD_SUNLOCK;
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mtx_unlock(&Giant);
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return (error);
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}
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/*
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* MPSAFE
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*/
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int
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modfnext(struct thread *td, struct modfnext_args *uap)
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{
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module_t mod;
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int error;
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td->td_retval[0] = -1;
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mtx_lock(&Giant);
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MOD_SLOCK;
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mod = module_lookupbyid(SCARG(uap, modid));
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if (mod == NULL) {
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error = ENOENT;
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} else {
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error = 0;
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if (TAILQ_NEXT(mod, flink))
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td->td_retval[0] = TAILQ_NEXT(mod, flink)->id;
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else
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td->td_retval[0] = 0;
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}
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MOD_SUNLOCK;
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mtx_unlock(&Giant);
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return (error);
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}
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struct module_stat_v1 {
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int version; /* set to sizeof(struct module_stat) */
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char name[MAXMODNAME];
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int refs;
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int id;
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};
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/*
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* MPSAFE
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*/
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int
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modstat(struct thread *td, struct modstat_args *uap)
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{
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module_t mod;
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modspecific_t data;
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int error = 0;
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int id, namelen, refs, version;
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struct module_stat *stat;
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char *name;
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mtx_lock(&Giant);
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MOD_SLOCK;
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mod = module_lookupbyid(SCARG(uap, modid));
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if (mod == NULL) {
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MOD_SUNLOCK;
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error = ENOENT;
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goto out;
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}
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id = mod->id;
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refs = mod->refs;
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name = mod->name;
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data = mod->data;
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MOD_SUNLOCK;
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stat = SCARG(uap, stat);
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/*
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* Check the version of the user's structure.
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*/
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if ((error = copyin(&stat->version, &version, sizeof(version))) != 0)
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goto out;
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if (version != sizeof(struct module_stat_v1)
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&& version != sizeof(struct module_stat)) {
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error = EINVAL;
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goto out;
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}
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namelen = strlen(mod->name) + 1;
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if (namelen > MAXMODNAME)
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namelen = MAXMODNAME;
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if ((error = copyout(name, &stat->name[0], namelen)) != 0)
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goto out;
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if ((error = copyout(&refs, &stat->refs, sizeof(int))) != 0)
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goto out;
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if ((error = copyout(&id, &stat->id, sizeof(int))) != 0)
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goto out;
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/*
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* >v1 stat includes module data.
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*/
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if (version == sizeof(struct module_stat)) {
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if ((error = copyout(&data, &stat->data,
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sizeof(data))) != 0)
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goto out;
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}
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td->td_retval[0] = 0;
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out:
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mtx_unlock(&Giant);
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return (error);
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}
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/*
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* MPSAFE
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*/
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int
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modfind(struct thread *td, struct modfind_args *uap)
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{
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int error = 0;
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char name[MAXMODNAME];
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module_t mod;
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if ((error = copyinstr(SCARG(uap, name), name, sizeof name, 0)) != 0)
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goto out;
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mtx_lock(&Giant);
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MOD_SLOCK;
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mod = module_lookupbyname(name);
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if (mod == NULL)
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error = ENOENT;
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else
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td->td_retval[0] = module_getid(mod);
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MOD_SUNLOCK;
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mtx_unlock(&Giant);
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out:
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return (error);
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}
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