- Lock down the ``module'' structure by adding an SX lock that is used by
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@
This commit is contained in:
Andrew R. Reiter
parent
0af93efb4d
commit
9b3851e9e3
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=92547
@ -37,6 +37,7 @@
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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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#include <sys/fcntl.h>
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@ -45,7 +46,6 @@
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#include <sys/vnode.h>
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#include <sys/sysctl.h>
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#include "linker_if.h"
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#ifdef KLD_DEBUG
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@ -274,11 +274,6 @@ linker_file_register_modules(linker_file_t lf)
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moddata = (*mdp)->md_data;
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KLD_DPF(FILE, ("Registering module %s in %s\n",
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moddata->name, lf->filename));
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if (module_lookupbyname(moddata->name) != NULL) {
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printf("Warning: module %s already exists\n",
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moddata->name);
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continue; /* or return a error ? */
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}
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error = module_register(moddata, lf);
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if (error)
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printf("Module %s failed to register: %d\n",
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@ -447,8 +442,10 @@ linker_file_unload(linker_file_t file)
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/*
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* Inform any modules associated with this file.
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*/
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MOD_XLOCK;
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for (mod = TAILQ_FIRST(&file->modules); mod; mod = next) {
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next = module_getfnext(mod);
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MOD_XUNLOCK;
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/*
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* Give the module a chance to veto the unload.
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@ -458,9 +455,11 @@ linker_file_unload(linker_file_t file)
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" vetoes unload\n", mod));
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lockmgr(&lock, LK_RELEASE, 0, curthread);
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goto out;
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}
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} else
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MOD_XLOCK;
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module_release(mod);
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}
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MOD_XUNLOCK;
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}
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file->refs--;
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if (file->refs > 0) {
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@ -900,11 +899,13 @@ kldfirstmod(struct thread *td, struct kldfirstmod_args *uap)
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mtx_lock(&Giant);
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lf = linker_find_file_by_id(SCARG(uap, fileid));
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if (lf) {
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MOD_SLOCK;
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mp = TAILQ_FIRST(&lf->modules);
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if (mp != NULL)
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td->td_retval[0] = module_getid(mp);
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else
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td->td_retval[0] = 0;
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MOD_SUNLOCK;
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} else
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error = ENOENT;
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mtx_unlock(&Giant);
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@ -33,11 +33,12 @@
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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/module.h>
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#include <sys/linker.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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@ -57,6 +58,7 @@ struct module {
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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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@ -66,11 +68,11 @@ modevent_nop(module_t mod, int what, void *arg)
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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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@ -83,8 +85,10 @@ 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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@ -94,14 +98,18 @@ module_register_init(const void *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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@ -114,16 +122,20 @@ module_register(const moduledata_t *data, linker_file_t container)
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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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@ -136,6 +148,7 @@ module_register(const moduledata_t *data, linker_file_t container)
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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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@ -143,6 +156,8 @@ 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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@ -151,17 +166,21 @@ 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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@ -171,6 +190,8 @@ module_lookupbyname(const char *name)
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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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@ -182,26 +203,28 @@ module_lookupbyname(const char *name)
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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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module_t mod;
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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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}
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return (NULL);
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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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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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@ -209,6 +232,7 @@ 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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@ -216,6 +240,7 @@ 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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@ -234,6 +259,7 @@ modnext(struct thread *td, struct modnext_args *uap)
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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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@ -252,6 +278,7 @@ modnext(struct thread *td, struct modnext_args *uap)
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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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@ -269,6 +296,7 @@ modfnext(struct thread *td, struct modfnext_args *uap)
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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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@ -279,6 +307,7 @@ modfnext(struct thread *td, struct modfnext_args *uap)
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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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@ -297,18 +326,26 @@ 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 namelen;
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int version;
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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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@ -324,20 +361,20 @@ modstat(struct thread *td, struct modstat_args *uap)
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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(mod->name, &stat->name[0], namelen)) != 0)
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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(&mod->refs, &stat->refs, sizeof(int))) != 0)
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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(&mod->id, &stat->id, sizeof(int))) != 0)
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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(&mod->data, &stat->data,
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sizeof(mod->data))) != 0)
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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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@ -360,11 +397,13 @@ modfind(struct thread *td, struct modfind_args *uap)
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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] = mod->id;
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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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@ -30,6 +30,9 @@
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#include <sys/sysproto.h>
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#include <sys/sysent.h>
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#include <sys/syscall.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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/*
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@ -96,7 +99,9 @@ syscall_module_handler(struct module *mod, int what, void *arg)
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if (error)
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return error;
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ms.intval = *data->offset;
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MOD_XLOCK;
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module_setspecific(mod, &ms);
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MOD_XUNLOCK;
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if (data->chainevh)
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error = data->chainevh(mod, what, data->chainarg);
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return error;
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@ -125,6 +125,15 @@ struct mod_metadata {
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MODULE_METADATA(_##module##_version, MDT_VERSION, \
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&_##module##_version, #module)
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extern struct sx modules_sx;
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#define MOD_XLOCK sx_xlock(&modules_sx)
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#define MOD_SLOCK sx_slock(&modules_sx)
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#define MOD_XUNLOCK sx_xunlock(&modules_sx)
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#define MOD_SUNLOCK sx_sunlock(&modules_sx)
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#define MOD_LOCK_ASSERT sx_assert(&modules_sx, SX_LOCKED)
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#define MOD_XLOCK_ASSERT sx_assert(&modules_sx, SX_XLOCKED)
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struct linker_file;
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void module_register_init(const void *);
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Block a user