freebsd-dev/sys/kern/subr_firmware.c
Robert Watson acd3428b7d Sweep kernel replacing suser(9) calls with priv(9) calls, assigning
specific privilege names to a broad range of privileges.  These may
require some future tweaking.

Sponsored by:           nCircle Network Security, Inc.
Obtained from:          TrustedBSD Project
Discussed on:           arch@
Reviewed (at least in part) by: mlaier, jmg, pjd, bde, ceri,
                        Alex Lyashkov <umka at sevcity dot net>,
                        Skip Ford <skip dot ford at verizon dot net>,
                        Antoine Brodin <antoine dot brodin at laposte dot net>
2006-11-06 13:42:10 +00:00

299 lines
7.6 KiB
C

/*-
* Copyright (c) 2005, Sam Leffler <sam@errno.com>
* 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 unmodified, 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 ``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 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/queue.h>
#include <sys/taskqueue.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/errno.h>
#include <sys/linker.h>
#include <sys/firmware.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/module.h>
#define FIRMWARE_MAX 30
static struct firmware firmware_table[FIRMWARE_MAX];
struct task firmware_task;
struct mtx firmware_mtx;
MTX_SYSINIT(firmware, &firmware_mtx, "firmware table", MTX_DEF);
/*
* Register a firmware image with the specified name. The
* image name must not already be registered. If this is a
* subimage then parent refers to a previously registered
* image that this should be associated with.
*/
struct firmware *
firmware_register(const char *imagename, const void *data, size_t datasize,
unsigned int version, struct firmware *parent)
{
struct firmware *frp = NULL;
int i;
mtx_lock(&firmware_mtx);
for (i = 0; i < FIRMWARE_MAX; i++) {
struct firmware *fp = &firmware_table[i];
if (fp->name == NULL) {
if (frp == NULL)
frp = fp;
continue;
}
if (strcasecmp(imagename, fp->name) == 0) {
mtx_unlock(&firmware_mtx);
printf("%s: image %s already registered!\n",
__func__, imagename);
return NULL;
}
}
if (frp == NULL) {
mtx_unlock(&firmware_mtx);
printf("%s: cannot register image %s, firmware table full!\n",
__func__, imagename);
return NULL;
}
frp->name = imagename;
frp->data = data;
frp->datasize = datasize;
frp->version = version;
frp->refcnt = 0;
frp->flags = 0;
if (parent != NULL)
parent->refcnt++;
frp->parent = parent;
frp->file = NULL;
mtx_unlock(&firmware_mtx);
return frp;
}
static void
clearentry(struct firmware *fp)
{
KASSERT(fp->refcnt == 0, ("image %s refcnt %u", fp->name, fp->refcnt));
fp->name = NULL;
fp->file = NULL;
fp->data = NULL;
fp->datasize = 0;
fp->version = 0;
fp->flags = 0;
if (fp->parent != NULL) { /* release parent reference */
fp->parent->refcnt--;
fp->parent = NULL;
}
}
static struct firmware *
lookup(const char *name)
{
struct firmware *fp;
int i;
for (i = 0; i < FIRMWARE_MAX; i++) {
fp = &firmware_table[i];
if (fp->name != NULL && strcasecmp(name, fp->name) == 0)
return fp;
}
return NULL;
}
/*
* Unregister/remove a firmware image. If there are outstanding
* references an error is returned and the image is not removed
* from the registry.
*/
int
firmware_unregister(const char *imagename)
{
struct firmware *fp;
int refcnt = 0;
mtx_lock(&firmware_mtx);
/*
* NB: it is ok for the lookup to fail; this can happen
* when a module is unloaded on last reference and the
* module unload handler unregister's each of it's
* firmware images.
*/
fp = lookup(imagename);
if (fp != NULL) {
refcnt = fp->refcnt;
if (refcnt == 0)
clearentry(fp);
}
mtx_unlock(&firmware_mtx);
return (refcnt != 0 ? EBUSY : 0);
}
/*
* Lookup and potentially load the specified firmware image.
* If the firmware is not found in the registry attempt to
* load a kernel module with the image name. If the firmware
* is located a reference is returned. The caller must release
* this reference for the image to be eligible for removal/unload.
*/
struct firmware *
firmware_get(const char *imagename)
{
struct thread *td;
struct firmware *fp;
linker_file_t result;
int requested_load = 0;
again:
mtx_lock(&firmware_mtx);
fp = lookup(imagename);
if (fp != NULL) {
if (requested_load)
fp->file = result;
fp->refcnt++;
mtx_unlock(&firmware_mtx);
return fp;
}
/*
* Image not present, try to load the module holding it
* or if we already tried give up.
*/
mtx_unlock(&firmware_mtx);
if (requested_load) {
printf("%s: failed to load firmware image %s\n",
__func__, imagename);
return NULL;
}
td = curthread;
if (priv_check(td, PRIV_FIRMWARE_LOAD) != 0 ||
securelevel_gt(td->td_ucred, 0) != 0) {
printf("%s: insufficient privileges to "
"load firmware image %s\n", __func__, imagename);
return NULL;
}
(void) linker_reference_module(imagename, NULL, &result);
requested_load = 1;
goto again; /* sort of an Algol-style for loop */
}
static void
unloadentry(void *unused1, int unused2)
{
struct firmware *fp;
linker_file_t file;
int i, err;
mtx_lock(&firmware_mtx);
for (;;) {
/* Look for an unwanted entry that we explicitly loaded. */
for (i = 0; i < FIRMWARE_MAX; i++) {
fp = &firmware_table[i];
if (fp->name != NULL && fp->file != NULL &&
fp->refcnt == 0 &&
(fp->flags & FIRMWAREFLAG_KEEPKLDREF) == 0)
break;
fp = NULL;
}
if (fp == NULL)
break;
file = fp->file;
/* No longer explicitly loaded. */
fp->file = NULL;
mtx_unlock(&firmware_mtx);
err = linker_release_module(NULL, NULL, file);
mtx_lock(&firmware_mtx);
if (err) {
/*
* If linker_release_module() failed then we still
* hold a reference on the module so it should not be
* possible for it to go away or be re-registered.
*/
KASSERT(fp->file == NULL,
("firmware entry reused while referenced!"));
fp->file = file;
}
}
mtx_unlock(&firmware_mtx);
}
/*
* Release a reference to a firmware image returned by
* firmware_get. The reference is released and if this is
* the last reference to the firmware image the associated
* module may be released/unloaded.
*/
void
firmware_put(struct firmware *fp, int flags)
{
mtx_lock(&firmware_mtx);
fp->refcnt--;
if (fp->refcnt == 0) {
if ((flags & FIRMWARE_UNLOAD) == 0)
fp->flags |= FIRMWAREFLAG_KEEPKLDREF;
}
if (fp->file)
taskqueue_enqueue(taskqueue_thread, &firmware_task);
mtx_unlock(&firmware_mtx);
}
/*
* Module glue.
*/
static int
firmware_modevent(module_t mod, int type, void *unused)
{
struct firmware *fp;
int i;
switch (type) {
case MOD_LOAD:
TASK_INIT(&firmware_task, 0, unloadentry, NULL);
return 0;
case MOD_UNLOAD:
for (i = 0; i < FIRMWARE_MAX; i++) {
fp = &firmware_table[i];
fp->flags &= ~FIRMWAREFLAG_KEEPKLDREF;
}
taskqueue_enqueue(taskqueue_thread, &firmware_task);
taskqueue_drain(taskqueue_thread, &firmware_task);
return 0;
}
return EINVAL;
}
static moduledata_t firmware_mod = {
"firmware",
firmware_modevent,
0
};
DECLARE_MODULE(firmware, firmware_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST);
MODULE_VERSION(firmware, 1);