Aren
/
NetBSD
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
NetBSD/sys/kern/kern_module.c

969 lines
21 KiB
C
Raw Blame History

/* $NetBSD: kern_module.c,v 1.31 2008/11/25 15:15:28 ad Exp $ */
/*-
* Copyright (c) 2008 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software developed for The NetBSD Foundation
* by Andrew Doran.
*
* 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/
/*
* Kernel module support.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kern_module.c,v 1.31 2008/11/25 15:15:28 ad Exp $");
#ifdef _KERNEL_OPT
#include "opt_ddb.h"
#endif
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/fcntl.h>
#include <sys/proc.h>
#include <sys/kauth.h>
#include <sys/kobj.h>
#include <sys/kmem.h>
#include <sys/module.h>
#include <sys/kauth.h>
#include <sys/kthread.h>
#include <uvm/uvm_extern.h>
#include <machine/stdarg.h>
struct vm_map *module_map;
struct modlist module_list = TAILQ_HEAD_INITIALIZER(module_list);
struct modlist module_bootlist = TAILQ_HEAD_INITIALIZER(module_bootlist);
static module_t *module_active;
static char module_base[64];
u_int module_count;
kmutex_t module_lock;
u_int module_autotime = 10;
u_int module_gen = 1;
static kcondvar_t module_thread_cv;
static kmutex_t module_thread_lock;
static int module_thread_ticks;
/* Ensure that the kernel's link set isn't empty. */
static modinfo_t module_dummy;
__link_set_add_rodata(modules, module_dummy);
static module_t *module_lookup(const char *);
static int module_do_load(const char *, bool, int, prop_dictionary_t,
module_t **, modclass_t class, bool);
static int module_do_unload(const char *);
static void module_error(const char *, ...);
static int module_do_builtin(const char *, module_t **);
static int module_fetch_info(module_t *);
static void module_thread(void *);
/*
* module_error:
*
* Utility function: log an error.
*/
static void
module_error(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
printf("WARNING: module error: ");
vprintf(fmt, ap);
printf("\n");
va_end(ap);
}
/*
* module_init:
*
* Initialize the module subsystem.
*/
void
module_init(void)
{
extern struct vm_map *module_map;
int error;
if (module_map == NULL) {
module_map = kernel_map;
}
mutex_init(&module_lock, MUTEX_DEFAULT, IPL_NONE);
cv_init(&module_thread_cv, "modunload");
mutex_init(&module_thread_lock, MUTEX_DEFAULT, IPL_NONE);
#ifdef MODULAR /* XXX */
module_init_md();
#endif
#if __NetBSD_Version__ / 1000000 % 100 == 99 /* -current */
snprintf(module_base, sizeof(module_base), "/stand/%s/%s/modules",
machine, osrelease);
#else /* release */
snprintf(module_base, sizeof(module_base), "/stand/%s/%d.%d/modules",
machine, __NetBSD_Version__ / 100000000,
__NetBSD_Version__ / 1000000 % 100);
#endif
error = kthread_create(PRI_VM, KTHREAD_MPSAFE, NULL, module_thread,
NULL, NULL, "modunload");
if (error != 0)
panic("module_init: %d", error);
}
/*
* module_init_class:
*
* Initialize all built-in and pre-loaded modules of the
* specified class.
*/
void
module_init_class(modclass_t class)
{
__link_set_decl(modules, modinfo_t);
modinfo_t *const *mip, *mi;
module_t *mod;
mutex_enter(&module_lock);
/*
* Builtins first. These can't depend on pre-loaded modules.
*/
__link_set_foreach(mip, modules) {
mi = *mip;
if (mi == &module_dummy) {
continue;
}
if (class != MODULE_CLASS_ANY && class != mi->mi_class) {
continue;
}
(void)module_do_builtin(mi->mi_name, NULL);
}
/*
* Now preloaded modules. These will be pulled off the
* list as we call module_do_load();
*/
do {
TAILQ_FOREACH(mod, &module_bootlist, mod_chain) {
mi = mod->mod_info;
if (class != MODULE_CLASS_ANY &&
class != mi->mi_class)
continue;
module_do_load(mi->mi_name, false, 0, NULL, NULL,
class, true);
break;
}
} while (mod != NULL);
mutex_exit(&module_lock);
}
/*
* module_compatible:
*
* Return true if the two supplied kernel versions are said to
* have the same binary interface for kernel code. The entire
* version is signficant for the development tree (-current),
* major and minor versions are significant for official
* releases of the system.
*/
bool
module_compatible(int v1, int v2)
{
#if __NetBSD_Version__ / 1000000 % 100 == 99 /* -current */
return v1 == v2;
#else /* release */
return abs(v1 - v2) < 10000;
#endif
}
/*
* module_load:
*
* Load a single module from the file system.
*/
int
module_load(const char *filename, int flags, prop_dictionary_t props,
modclass_t class)
{
int error;
/* Authorize. */
error = kauth_authorize_system(kauth_cred_get(), KAUTH_SYSTEM_MODULE,
0, (void *)(uintptr_t)MODCTL_LOAD, NULL, NULL);
if (error != 0) {
return error;
}
mutex_enter(&module_lock);
error = module_do_load(filename, false, flags, props, NULL, class,
false);
mutex_exit(&module_lock);
return error;
}
/*
* module_autoload:
*
* Load a single module from the file system, system initiated.
*/
int
module_autoload(const char *filename, modclass_t class)
{
int error;
KASSERT(mutex_owned(&module_lock));
/* Disallow path seperators and magic symlinks. */
if (strchr(filename, '/') != NULL || strchr(filename, '@') != NULL ||
strchr(filename, '.') != NULL) {
return EPERM;
}
/* Authorize. */
error = kauth_authorize_system(kauth_cred_get(), KAUTH_SYSTEM_MODULE,
0, (void *)(uintptr_t)MODCTL_LOAD, (void *)(uintptr_t)1, NULL);
if (error != 0) {
return error;
}
return module_do_load(filename, false, 0, NULL, NULL, class, true);
}
/*
* module_unload:
*
* Find and unload a module by name.
*/
int
module_unload(const char *name)
{
int error;
/* Authorize. */
error = kauth_authorize_system(kauth_cred_get(), KAUTH_SYSTEM_MODULE,
0, (void *)(uintptr_t)MODCTL_UNLOAD, NULL, NULL);
if (error != 0) {
return error;
}
mutex_enter(&module_lock);
error = module_do_unload(name);
mutex_exit(&module_lock);
return error;
}
/*
* module_lookup:
*
* Look up a module by name.
*/
module_t *
module_lookup(const char *name)
{
module_t *mod;
KASSERT(mutex_owned(&module_lock));
TAILQ_FOREACH(mod, &module_list, mod_chain) {
if (strcmp(mod->mod_info->mi_name, name) == 0) {
break;
}
}
return mod;
}
/*
* module_hold:
*
* Add a single reference to a module. It's the caller's
* responsibility to ensure that the reference is dropped
* later.
*/
int
module_hold(const char *name)
{
module_t *mod;
mutex_enter(&module_lock);
mod = module_lookup(name);
if (mod == NULL) {
mutex_exit(&module_lock);
return ENOENT;
}
mod->mod_refcnt++;
mutex_exit(&module_lock);
return 0;
}
/*
* module_rele:
*
* Release a reference acquired with module_hold().
*/
void
module_rele(const char *name)
{
module_t *mod;
mutex_enter(&module_lock);
mod = module_lookup(name);
if (mod == NULL) {
mutex_exit(&module_lock);
panic("module_rele: gone");
}
mod->mod_refcnt--;
mutex_exit(&module_lock);
}
/*
* module_enqueue:
*
* Put a module onto the global list and update counters.
*/
static void
module_enqueue(module_t *mod)
{
int i;
/*
* If there are requisite modules, put at the head of the queue.
* This is so that autounload can unload requisite modules with
* only one pass through the queue.
*/
if (mod->mod_nrequired) {
TAILQ_INSERT_HEAD(&module_list, mod, mod_chain);
/* Add references to the requisite modules. */
for (i = 0; i < mod->mod_nrequired; i++) {
KASSERT(mod->mod_required[i] != NULL);
mod->mod_required[i]->mod_refcnt++;
}
} else {
TAILQ_INSERT_TAIL(&module_list, mod, mod_chain);
}
module_count++;
module_gen++;
}
/*
* module_do_builtin:
*
* Initialize a single module from the list of modules that are
* built into the kernel (linked into the kernel image).
*/
static int
module_do_builtin(const char *name, module_t **modp)
{
__link_set_decl(modules, modinfo_t);
modinfo_t *const *mip;
const char *p, *s;
char buf[MAXMODNAME];
modinfo_t *mi;
module_t *mod, *mod2;
size_t len;
int error;
KASSERT(mutex_owned(&module_lock));
/*
* Check to see if already loaded.
*/
if ((mod = module_lookup(name)) != NULL) {
if (modp != NULL) {
*modp = mod;
}
return 0;
}
/*
* Search the list to see if we have a module by this name.
*/
error = ENOENT;
__link_set_foreach(mip, modules) {
mi = *mip;
if (mi == &module_dummy) {
continue;
}
if (strcmp(mi->mi_name, name) == 0) {
error = 0;
break;
}
}
if (error != 0) {
return error;
}
/*
* Initialize pre-requisites.
*/
mod = kmem_zalloc(sizeof(*mod), KM_SLEEP);
if (mod == NULL) {
return ENOMEM;
}
if (modp != NULL) {
*modp = mod;
}
if (mi->mi_required != NULL) {
for (s = mi->mi_required; *s != '\0'; s = p) {
if (*s == ',')
s++;
p = s;
while (*p != '\0' && *p != ',')
p++;
len = min(p - s + 1, sizeof(buf));
strlcpy(buf, s, len);
if (buf[0] == '\0')
break;
if (mod->mod_nrequired == MAXMODDEPS - 1) {
module_error("too many required modules");
kmem_free(mod, sizeof(*mod));
return EINVAL;
}
error = module_do_builtin(buf, &mod2);
if (error != 0) {
kmem_free(mod, sizeof(*mod));
return error;
}
mod->mod_required[mod->mod_nrequired++] = mod2;
}
}
/*
* Try to initialize the module.
*/
KASSERT(module_active == NULL);
module_active = mod;
error = (*mi->mi_modcmd)(MODULE_CMD_INIT, NULL);
module_active = NULL;
if (error != 0) {
module_error("builtin module `%s' "
"failed to init", mi->mi_name);
kmem_free(mod, sizeof(*mod));
return error;
}
mod->mod_info = mi;
mod->mod_source = MODULE_SOURCE_KERNEL;
module_enqueue(mod);
return 0;
}
/*
* module_do_load:
*
* Helper routine: load a module from the file system, or one
* pushed by the boot loader.
*/
static int
module_do_load(const char *name, bool isdep, int flags,
prop_dictionary_t props, module_t **modp, modclass_t class,
bool autoload)
{
static TAILQ_HEAD(,module) pending = TAILQ_HEAD_INITIALIZER(pending);
static int depth;
const int maxdepth = 6;
modinfo_t *mi;
module_t *mod, *mod2;
char buf[MAXMODNAME];
const char *s, *p;
int error;
size_t len;
KASSERT(mutex_owned(&module_lock));
error = 0;
/*
* Avoid recursing too far.
*/
if (++depth > maxdepth) {
module_error("too many required modules");
depth--;
return EMLINK;
}
/*
* Load the module and link. Before going to the file system,
* scan the list of modules loaded by the boot loader. Just
* before init is started the list of modules loaded at boot
* will be purged. Before init is started we can assume that
* `name' is a module name and not a path name.
*/
TAILQ_FOREACH(mod, &module_bootlist, mod_chain) {
if (strcmp(mod->mod_info->mi_name, name) == 0) {
TAILQ_REMOVE(&module_bootlist, mod, mod_chain);
break;
}
}
if (mod != NULL) {
TAILQ_INSERT_TAIL(&pending, mod, mod_chain);
} else {
/*
* If a requisite module, check to see if it is
* already present.
*/
if (isdep) {
TAILQ_FOREACH(mod, &module_list, mod_chain) {
if (strcmp(mod->mod_info->mi_name, name) == 0) {
break;
}
}
if (mod != NULL) {
if (modp != NULL) {
*modp = mod;
}
depth--;
return 0;
}
}
mod = kmem_zalloc(sizeof(*mod), KM_SLEEP);
if (mod == NULL) {
depth--;
return ENOMEM;
}
error = kobj_load_file(&mod->mod_kobj, name, module_base,
autoload);
if (error != 0) {
kmem_free(mod, sizeof(*mod));
depth--;
if (!autoload) {
module_error("unable to load kernel object");
}
return error;
}
TAILQ_INSERT_TAIL(&pending, mod, mod_chain);
mod->mod_source = MODULE_SOURCE_FILESYS;
error = module_fetch_info(mod);
if (error != 0) {
goto fail;
}
}
/*
* Check compatibility.
*/
mi = mod->mod_info;
if (strlen(mi->mi_name) >= MAXMODNAME) {
error = EINVAL;
module_error("module name too long");
goto fail;
}
if (!module_compatible(mi->mi_version, __NetBSD_Version__)) {
module_error("module built for different version of system");
if ((flags & MODCTL_LOAD_FORCE) != 0) {
module_error("forced load, system may be unstable");
} else {
error = EPROGMISMATCH;
goto fail;
}
}
/*
* If a specific kind of module was requested, ensure that we have
* a match.
*/
if (class != MODULE_CLASS_ANY && class != mi->mi_class) {
error = ENOENT;
goto fail;
}
/*
* If loading a dependency, `name' is a plain module name.
* The name must match.
*/
if (isdep && strcmp(mi->mi_name, name) != 0) {
error = ENOENT;
goto fail;
}
/*
* Check to see if the module is already loaded. If so, we may
* have been recursively called to handle a dependency, so be sure
* to set modp.
*/
if ((mod2 = module_lookup(mi->mi_name)) != NULL) {
if (modp != NULL)
*modp = mod2;
error = EEXIST;
goto fail;
}
/*
* Block circular dependencies.
*/
TAILQ_FOREACH(mod2, &pending, mod_chain) {
if (mod == mod2) {
continue;
}
if (strcmp(mod2->mod_info->mi_name, mi->mi_name) == 0) {
error = EDEADLK;
module_error("circular dependency detected");
goto fail;
}
}
/*
* Now try to load any requisite modules.
*/
if (mi->mi_required != NULL) {
for (s = mi->mi_required; *s != '\0'; s = p) {
if (*s == ',')
s++;
p = s;
while (*p != '\0' && *p != ',')
p++;
len = p - s + 1;
if (len >= MAXMODNAME) {
error = EINVAL;
module_error("required module name too long");
goto fail;
}
strlcpy(buf, s, len);
if (buf[0] == '\0')
break;
if (mod->mod_nrequired == MAXMODDEPS - 1) {
error = EINVAL;
module_error("too many required modules");
goto fail;
}
if (strcmp(buf, mi->mi_name) == 0) {
error = EDEADLK;
module_error("self-dependency detected");
goto fail;
}
error = module_do_load(buf, true, flags, NULL,
&mod->mod_required[mod->mod_nrequired++],
MODULE_CLASS_ANY, true);
if (error != 0)
goto fail;
}
}
/*
* We loaded all needed modules successfully: perform global
* relocations and initialize.
*/
error = kobj_affix(mod->mod_kobj, mi->mi_name);
if (error != 0) {
module_error("unable to affix module");
goto fail2;
}
KASSERT(module_active == NULL);
module_active = mod;
error = (*mi->mi_modcmd)(MODULE_CMD_INIT, props);
module_active = NULL;
if (error != 0) {
module_error("modctl function returned error %d", error);
goto fail;
}
/*
* Good, the module loaded successfully. Put it onto the
* list and add references to its requisite modules.
*/
TAILQ_REMOVE(&pending, mod, mod_chain);
module_enqueue(mod);
if (modp != NULL) {
*modp = mod;
}
if (autoload) {
/*
* Arrange to try unloading the module after
* a short delay.
*/
mod->mod_autotime = time_second + module_autotime;
module_thread_kick();
}
depth--;
return 0;
fail:
kobj_unload(mod->mod_kobj);
fail2:
TAILQ_REMOVE(&pending, mod, mod_chain);
kmem_free(mod, sizeof(*mod));
depth--;
return error;
}
/*
* module_do_unload:
*
* Helper routine: do the dirty work of unloading a module.
*/
static int
module_do_unload(const char *name)
{
module_t *mod;
int error;
u_int i;
KASSERT(mutex_owned(&module_lock));
mod = module_lookup(name);
if (mod == NULL) {
return ENOENT;
}
if (mod->mod_refcnt != 0 || mod->mod_source == MODULE_SOURCE_KERNEL) {
return EBUSY;
}
KASSERT(module_active == NULL);
module_active = mod;
error = (*mod->mod_info->mi_modcmd)(MODULE_CMD_FINI, NULL);
module_active = NULL;
if (error != 0) {
return error;
}
module_count--;
TAILQ_REMOVE(&module_list, mod, mod_chain);
for (i = 0; i < mod->mod_nrequired; i++) {
mod->mod_required[i]->mod_refcnt--;
}
if (mod->mod_kobj != NULL) {
kobj_unload(mod->mod_kobj);
}
kmem_free(mod, sizeof(*mod));
module_gen++;
return 0;
}
/*
* module_prime:
*
* Push a module loaded by the bootloader onto our internal
* list.
*/
int
module_prime(void *base, size_t size)
{
module_t *mod;
int error;
mod = kmem_zalloc(sizeof(*mod), KM_SLEEP);
if (mod == NULL) {
return ENOMEM;
}
mod->mod_source = MODULE_SOURCE_BOOT;
error = kobj_load_mem(&mod->mod_kobj, base, size);
if (error != 0) {
kmem_free(mod, sizeof(*mod));
module_error("unable to load object pushed by boot loader");
return error;
}
error = module_fetch_info(mod);
if (error != 0) {
kobj_unload(mod->mod_kobj);
kmem_free(mod, sizeof(*mod));
module_error("unable to load object pushed by boot loader");
return error;
}
TAILQ_INSERT_TAIL(&module_bootlist, mod, mod_chain);
return 0;
}
/*
* module_fetch_into:
*
* Fetch modinfo record from a loaded module.
*/
static int
module_fetch_info(module_t *mod)
{
int error;
void *addr;
size_t size;
/*
* Find module info record and check compatibility.
*/
error = kobj_find_section(mod->mod_kobj, "link_set_modules",
&addr, &size);
if (error != 0) {
module_error("`link_set_modules' section not present");
return error;
}
if (size != sizeof(modinfo_t **)) {
module_error("`link_set_modules' section wrong size");
return error;
}
mod->mod_info = *(modinfo_t **)addr;
return 0;
}
/*
* module_find_section:
*
* Allows a module that is being initialized to look up a section
* within its ELF object.
*/
int
module_find_section(const char *name, void **addr, size_t *size)
{
KASSERT(mutex_owned(&module_lock));
KASSERT(module_active != NULL);
return kobj_find_section(module_active->mod_kobj, name, addr, size);
}
/*
* module_thread:
*
* Automatically unload modules. We try once to unload autoloaded
* modules after module_autotime seconds. If the system is under
* severe memory pressure, we'll try unloading all modules.
*/
static void
module_thread(void *cookie)
{
module_t *mod, *next;
modinfo_t *mi;
int error;
for (;;) {
mutex_enter(&module_lock);
for (mod = TAILQ_FIRST(&module_list); mod != NULL; mod = next) {
next = TAILQ_NEXT(mod, mod_chain);
if (uvmexp.free < uvmexp.freemin) {
module_thread_ticks = hz;
} else if (mod->mod_autotime == 0) {
continue;
} else if (time_second < mod->mod_autotime) {
module_thread_ticks = hz;
continue;
} else {
mod->mod_autotime = 0;
}
/*
* If this module wants to avoid autounload then
* skip it. Some modules can ping-pong in and out
* because their use is transient but often.
* Example: exec_script.
*/
mi = mod->mod_info;
error = (*mi->mi_modcmd)(MODULE_CMD_AUTOUNLOAD, NULL);
if (error == 0 || error == ENOTTY) {
(void)module_do_unload(mi->mi_name);
}
}
mutex_exit(&module_lock);
mutex_enter(&module_thread_lock);
(void)cv_timedwait(&module_thread_cv, &module_thread_lock,
module_thread_ticks);
module_thread_ticks = 0;
mutex_exit(&module_thread_lock);
}
}
/*
* module_thread:
*
* Kick the module thread into action, perhaps because the
* system is low on memory.
*/
void
module_thread_kick(void)
{
mutex_enter(&module_thread_lock);
module_thread_ticks = hz;
cv_broadcast(&module_thread_cv);
mutex_exit(&module_thread_lock);
}
#ifdef DDB
/*
* module_whatis:
*
* Helper routine for DDB.
*/
void
module_whatis(uintptr_t addr, void (*pr)(const char *, ...))
{
module_t *mod;
size_t msize;
vaddr_t maddr;
TAILQ_FOREACH(mod, &module_list, mod_chain) {
kobj_stat(mod->mod_kobj, &maddr, &msize);
if (addr < maddr || addr >= maddr + msize) {
continue;
}
(*pr)("%p is %p+%zu, in kernel module `%s'\n",
(void *)addr, (void *)maddr,
(size_t)(addr - maddr), mod->mod_info->mi_name);
}
}
/*
* module_print_list:
*
* Helper routine for DDB.
*/
void
module_print_list(void (*pr)(const char *, ...))
{
const char *src;
module_t *mod;
size_t msize;
vaddr_t maddr;
(*pr)("%16s %16s %8s %8s\n", "NAME", "TEXT/DATA", "SIZE", "SOURCE");
TAILQ_FOREACH(mod, &module_list, mod_chain) {
switch (mod->mod_source) {
case MODULE_SOURCE_KERNEL:
src = "builtin";
break;
case MODULE_SOURCE_FILESYS:
src = "filesys";
break;
case MODULE_SOURCE_BOOT:
src = "boot";
break;
default:
src = "unknown";
break;
}
kobj_stat(mod->mod_kobj, &maddr, &msize);
(*pr)("%16s %16lx %8ld %8s\n", mod->mod_info->mi_name,
(long)maddr, (long)msize, src);
}
}
#endif /* DDB */
Reference in New Issue View Git Blame Copy Permalink