freebsd-nq/sys/kern/kern_module.c
Peter Wemm 54823af256 First round implementation of a fine grain enhanced module to module
version dependency system.  This isn't quite finished, but it is at a
useful stage to do a functional checkpoint.

Highlights:
- version and dependency metadata is gathered via linker sets, so things
are handled the same for static kernels and code built to live in a kld.
- The dependencies are at module level (versus at file level).
- Dependencies determine kld symbol search order - this means that you
cannot link against symbols in another file unless you depend on it. This
is so that you cannot accidently unload the target out from underneath
the ones referencing it.
- It is flexible enough that we can put tags in #include files and macros
so that we can get decent hooks for enforcing recompiles on incompatable
ABI changes.  eg: if we change struct proc, we could force a recompile
for all kld's that reference the proc struct.
- Tangled dependency references at boot time are sorted.  Files are
relocated once all their dependencies are already relocated.

Caveats:
- Loader support is incomplete, but has been worked on seperately.
- Actual enforcement of the version number tags is not active yet - just
the module dependencies are live.  The actual structure of versioning
hasn't been agreed on yet. (eg: major.minor, or whatever)
- There is some backwards compatability for old modules without metadata
but I'm not sure how good it is.

This is based on work originally done by Boris Popov (bp@freebsd.org),
but I'm not sure he'd recognize much of it now. Don't blame him. :-)
Also, ideas have been borrowed from Mike Smith.
2000-04-29 13:19:31 +00:00

340 lines
7.7 KiB
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.
*
* $FreeBSD$
*/
#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>
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;
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_SUB_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)
panic("module_register_init: module named %s not found\n", data->name);
error = MOD_EVENT(mod, MOD_LOAD);
if (error) {
MOD_EVENT(mod, MOD_UNLOAD);
module_release(mod);
printf("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) {
printf("module_register: module %s already exists!\n", data->name);
return EEXIST;
}
namelen = strlen(data->name) + 1;
newmod = (module_t) malloc(sizeof(struct module) + namelen,
M_MODULE, M_WAITOK);
if (newmod == 0)
return ENOMEM;
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)
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++;
}
void
module_release(module_t mod)
{
if (mod->refs <= 0)
panic("module_release: bad reference count");
MOD_DPF(REFS, ("module_release: before, refs=%d\n", mod->refs));
mod->refs--;
if (mod->refs == 0) {
TAILQ_REMOVE(&modules, mod, link);
if (mod->file) {
TAILQ_REMOVE(&mod->file->modules, mod, flink);
}
free(mod, M_MODULE);
}
}
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 0;
}
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 0;
}
int
module_unload(module_t mod)
{
return MOD_EVENT(mod, MOD_UNLOAD);
}
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.
*/
int
modnext(struct proc* p, struct modnext_args* uap)
{
module_t mod;
p->p_retval[0] = -1;
if (SCARG(uap, modid) == 0) {
mod = TAILQ_FIRST(&modules);
if (mod) {
p->p_retval[0] = mod->id;
return 0;
} else
return ENOENT;
}
mod = module_lookupbyid(SCARG(uap, modid));
if (!mod)
return ENOENT;
if (TAILQ_NEXT(mod, link))
p->p_retval[0] = TAILQ_NEXT(mod, link)->id;
else
p->p_retval[0] = 0;
return 0;
}
int
modfnext(struct proc* p, struct modfnext_args* uap)
{
module_t mod;
p->p_retval[0] = -1;
mod = module_lookupbyid(SCARG(uap, modid));
if (!mod)
return ENOENT;
if (TAILQ_NEXT(mod, flink))
p->p_retval[0] = TAILQ_NEXT(mod, flink)->id;
else
p->p_retval[0] = 0;
return 0;
}
struct module_stat_v1 {
int version; /* set to sizeof(struct module_stat) */
char name[MAXMODNAME];
int refs;
int id;
};
int
modstat(struct proc* p, struct modstat_args* uap)
{
module_t mod;
int error = 0;
int namelen;
int version;
struct module_stat* stat;
mod = module_lookupbyid(SCARG(uap, modid));
if (!mod)
return ENOENT;
stat = SCARG(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;
}
p->p_retval[0] = 0;
out:
return error;
}
int
modfind(struct proc* p, struct modfind_args* uap)
{
int error = 0;
char name[MAXMODNAME];
module_t mod;
if ((error = copyinstr(SCARG(uap, name), name, sizeof name, 0)) != 0)
goto out;
mod = module_lookupbyname(name);
if (!mod)
error = ENOENT;
else
p->p_retval[0] = mod->id;
out:
return error;
}