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freebsd-dev/sys/kern/kern_linker.c
Mark Johnston 9e575fadf4 link_elf_obj: Invoke fini callbacks 
This is required for KASAN: when a module is unloaded, poisoned regions
(e.g., pad areas between global variables) are left as such, so if they
are reused as KLDs are loaded, false positives can arise.

Reported by:	pho, Jenkins
Reviewed by:	kib
MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D31339
2021-07-29 09:46:25 -04:00

2329 lines
55 KiB
C
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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 1997-2000 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_ddb.h"
#include "opt_kld.h"
#include "opt_hwpmc_hooks.h"
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/sysproto.h>
#include <sys/sysent.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/sx.h>
#include <sys/module.h>
#include <sys/mount.h>
#include <sys/linker.h>
#include <sys/eventhandler.h>
#include <sys/fcntl.h>
#include <sys/jail.h>
#include <sys/libkern.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/syscallsubr.h>
#include <sys/sysctl.h>
#ifdef DDB
#include <ddb/ddb.h>
#endif
#include <net/vnet.h>
#include <security/mac/mac_framework.h>
#include "linker_if.h"
#ifdef HWPMC_HOOKS
#include <sys/pmckern.h>
#endif
#ifdef KLD_DEBUG
int kld_debug = 0;
SYSCTL_INT(_debug, OID_AUTO, kld_debug, CTLFLAG_RWTUN,
&kld_debug, 0, "Set various levels of KLD debug");
#endif
/* These variables are used by kernel debuggers to enumerate loaded files. */
const int kld_off_address = offsetof(struct linker_file, address);
const int kld_off_filename = offsetof(struct linker_file, filename);
const int kld_off_pathname = offsetof(struct linker_file, pathname);
const int kld_off_next = offsetof(struct linker_file, link.tqe_next);
/*
* static char *linker_search_path(const char *name, struct mod_depend
* *verinfo);
*/
static const char *linker_basename(const char *path);
/*
* Find a currently loaded file given its filename.
*/
static linker_file_t linker_find_file_by_name(const char* _filename);
/*
* Find a currently loaded file given its file id.
*/
static linker_file_t linker_find_file_by_id(int _fileid);
/* Metadata from the static kernel */
SET_DECLARE(modmetadata_set, struct mod_metadata);
MALLOC_DEFINE(M_LINKER, "linker", "kernel linker");
linker_file_t linker_kernel_file;
static struct sx kld_sx; /* kernel linker lock */
static bool kld_busy;
/*
* Load counter used by clients to determine if a linker file has been
* re-loaded. This counter is incremented for each file load.
*/
static int loadcnt;
static linker_class_list_t classes;
static linker_file_list_t linker_files;
static int next_file_id = 1;
static int linker_no_more_classes = 0;
#define LINKER_GET_NEXT_FILE_ID(a) do { \
linker_file_t lftmp; \
\
if (!cold) \
sx_assert(&kld_sx, SA_XLOCKED); \
retry: \
TAILQ_FOREACH(lftmp, &linker_files, link) { \
if (next_file_id == lftmp->id) { \
next_file_id++; \
goto retry; \
} \
} \
(a) = next_file_id; \
} while (0)
/* XXX wrong name; we're looking at version provision tags here, not modules */
typedef TAILQ_HEAD(, modlist) modlisthead_t;
struct modlist {
TAILQ_ENTRY(modlist) link; /* chain together all modules */
linker_file_t container;
const char *name;
int version;
};
typedef struct modlist *modlist_t;
static modlisthead_t found_modules;
static int linker_file_add_dependency(linker_file_t file,
linker_file_t dep);
static caddr_t linker_file_lookup_symbol_internal(linker_file_t file,
const char* name, int deps);
static int linker_load_module(const char *kldname,
const char *modname, struct linker_file *parent,
const struct mod_depend *verinfo, struct linker_file **lfpp);
static modlist_t modlist_lookup2(const char *name, const struct mod_depend *verinfo);
static void
linker_init(void *arg)
{
sx_init(&kld_sx, "kernel linker");
TAILQ_INIT(&classes);
TAILQ_INIT(&linker_files);
}
SYSINIT(linker, SI_SUB_KLD, SI_ORDER_FIRST, linker_init, NULL);
static void
linker_stop_class_add(void *arg)
{
linker_no_more_classes = 1;
}
SYSINIT(linker_class, SI_SUB_KLD, SI_ORDER_ANY, linker_stop_class_add, NULL);
int
linker_add_class(linker_class_t lc)
{
/*
* We disallow any class registration past SI_ORDER_ANY
* of SI_SUB_KLD. We bump the reference count to keep the
* ops from being freed.
*/
if (linker_no_more_classes == 1)
return (EPERM);
kobj_class_compile((kobj_class_t) lc);
((kobj_class_t)lc)->refs++; /* XXX: kobj_mtx */
TAILQ_INSERT_TAIL(&classes, lc, link);
return (0);
}
static void
linker_file_sysinit(linker_file_t lf)
{
struct sysinit **start, **stop, **sipp, **xipp, *save;
KLD_DPF(FILE, ("linker_file_sysinit: calling SYSINITs for %s\n",
lf->filename));
sx_assert(&kld_sx, SA_XLOCKED);
if (linker_file_lookup_set(lf, "sysinit_set", &start, &stop, NULL) != 0)
return;
/*
* Perform a bubble sort of the system initialization objects by
* their subsystem (primary key) and order (secondary key).
*
* Since some things care about execution order, this is the operation
* which ensures continued function.
*/
for (sipp = start; sipp < stop; sipp++) {
for (xipp = sipp + 1; xipp < stop; xipp++) {
if ((*sipp)->subsystem < (*xipp)->subsystem ||
((*sipp)->subsystem == (*xipp)->subsystem &&
(*sipp)->order <= (*xipp)->order))
continue; /* skip */
save = *sipp;
*sipp = *xipp;
*xipp = save;
}
}
/*
* Traverse the (now) ordered list of system initialization tasks.
* Perform each task, and continue on to the next task.
*/
sx_xunlock(&kld_sx);
mtx_lock(&Giant);
for (sipp = start; sipp < stop; sipp++) {
if ((*sipp)->subsystem == SI_SUB_DUMMY)
continue; /* skip dummy task(s) */
/* Call function */
(*((*sipp)->func)) ((*sipp)->udata);
}
mtx_unlock(&Giant);
sx_xlock(&kld_sx);
}
static void
linker_file_sysuninit(linker_file_t lf)
{
struct sysinit **start, **stop, **sipp, **xipp, *save;
KLD_DPF(FILE, ("linker_file_sysuninit: calling SYSUNINITs for %s\n",
lf->filename));
sx_assert(&kld_sx, SA_XLOCKED);
if (linker_file_lookup_set(lf, "sysuninit_set", &start, &stop,
NULL) != 0)
return;
/*
* Perform a reverse bubble sort of the system initialization objects
* by their subsystem (primary key) and order (secondary key).
*
* Since some things care about execution order, this is the operation
* which ensures continued function.
*/
for (sipp = start; sipp < stop; sipp++) {
for (xipp = sipp + 1; xipp < stop; xipp++) {
if ((*sipp)->subsystem > (*xipp)->subsystem ||
((*sipp)->subsystem == (*xipp)->subsystem &&
(*sipp)->order >= (*xipp)->order))
continue; /* skip */
save = *sipp;
*sipp = *xipp;
*xipp = save;
}
}
/*
* Traverse the (now) ordered list of system initialization tasks.
* Perform each task, and continue on to the next task.
*/
sx_xunlock(&kld_sx);
mtx_lock(&Giant);
for (sipp = start; sipp < stop; sipp++) {
if ((*sipp)->subsystem == SI_SUB_DUMMY)
continue; /* skip dummy task(s) */
/* Call function */
(*((*sipp)->func)) ((*sipp)->udata);
}
mtx_unlock(&Giant);
sx_xlock(&kld_sx);
}
static void
linker_file_register_sysctls(linker_file_t lf, bool enable)
{
struct sysctl_oid **start, **stop, **oidp;
KLD_DPF(FILE,
("linker_file_register_sysctls: registering SYSCTLs for %s\n",
lf->filename));
sx_assert(&kld_sx, SA_XLOCKED);
if (linker_file_lookup_set(lf, "sysctl_set", &start, &stop, NULL) != 0)
return;
sx_xunlock(&kld_sx);
sysctl_wlock();
for (oidp = start; oidp < stop; oidp++) {
if (enable)
sysctl_register_oid(*oidp);
else
sysctl_register_disabled_oid(*oidp);
}
sysctl_wunlock();
sx_xlock(&kld_sx);
}
static void
linker_file_enable_sysctls(linker_file_t lf)
{
struct sysctl_oid **start, **stop, **oidp;
KLD_DPF(FILE,
("linker_file_enable_sysctls: enable SYSCTLs for %s\n",
lf->filename));
sx_assert(&kld_sx, SA_XLOCKED);
if (linker_file_lookup_set(lf, "sysctl_set", &start, &stop, NULL) != 0)
return;
sx_xunlock(&kld_sx);
sysctl_wlock();
for (oidp = start; oidp < stop; oidp++)
sysctl_enable_oid(*oidp);
sysctl_wunlock();
sx_xlock(&kld_sx);
}
static void
linker_file_unregister_sysctls(linker_file_t lf)
{
struct sysctl_oid **start, **stop, **oidp;
KLD_DPF(FILE, ("linker_file_unregister_sysctls: unregistering SYSCTLs"
" for %s\n", lf->filename));
sx_assert(&kld_sx, SA_XLOCKED);
if (linker_file_lookup_set(lf, "sysctl_set", &start, &stop, NULL) != 0)
return;
sx_xunlock(&kld_sx);
sysctl_wlock();
for (oidp = start; oidp < stop; oidp++)
sysctl_unregister_oid(*oidp);
sysctl_wunlock();
sx_xlock(&kld_sx);
}
static int
linker_file_register_modules(linker_file_t lf)
{
struct mod_metadata **start, **stop, **mdp;
const moduledata_t *moddata;
int first_error, error;
KLD_DPF(FILE, ("linker_file_register_modules: registering modules"
" in %s\n", lf->filename));
sx_assert(&kld_sx, SA_XLOCKED);
if (linker_file_lookup_set(lf, MDT_SETNAME, &start, &stop, NULL) != 0) {
/*
* This fallback should be unnecessary, but if we get booted
* from boot2 instead of loader and we are missing our
* metadata then we have to try the best we can.
*/
if (lf == linker_kernel_file) {
start = SET_BEGIN(modmetadata_set);
stop = SET_LIMIT(modmetadata_set);
} else
return (0);
}
first_error = 0;
for (mdp = start; mdp < stop; mdp++) {
if ((*mdp)->md_type != MDT_MODULE)
continue;
moddata = (*mdp)->md_data;
KLD_DPF(FILE, ("Registering module %s in %s\n",
moddata->name, lf->filename));
error = module_register(moddata, lf);
if (error) {
printf("Module %s failed to register: %d\n",
moddata->name, error);
if (first_error == 0)
first_error = error;
}
}
return (first_error);
}
static void
linker_init_kernel_modules(void)
{
sx_xlock(&kld_sx);
linker_file_register_modules(linker_kernel_file);
sx_xunlock(&kld_sx);
}
SYSINIT(linker_kernel, SI_SUB_KLD, SI_ORDER_ANY, linker_init_kernel_modules,
NULL);
static int
linker_load_file(const char *filename, linker_file_t *result)
{
linker_class_t lc;
linker_file_t lf;
int foundfile, error, modules;
/* Refuse to load modules if securelevel raised */
if (prison0.pr_securelevel > 0)
return (EPERM);
sx_assert(&kld_sx, SA_XLOCKED);
lf = linker_find_file_by_name(filename);
if (lf) {
KLD_DPF(FILE, ("linker_load_file: file %s is already loaded,"
" incrementing refs\n", filename));
*result = lf;
lf->refs++;
return (0);
}
foundfile = 0;
error = 0;
/*
* We do not need to protect (lock) classes here because there is
* no class registration past startup (SI_SUB_KLD, SI_ORDER_ANY)
* and there is no class deregistration mechanism at this time.
*/
TAILQ_FOREACH(lc, &classes, link) {
KLD_DPF(FILE, ("linker_load_file: trying to load %s\n",
filename));
error = LINKER_LOAD_FILE(lc, filename, &lf);
/*
* If we got something other than ENOENT, then it exists but
* we cannot load it for some other reason.
*/
if (error != ENOENT)
foundfile = 1;
if (lf) {
error = linker_file_register_modules(lf);
if (error == EEXIST) {
linker_file_unload(lf, LINKER_UNLOAD_FORCE);
return (error);
}
modules = !TAILQ_EMPTY(&lf->modules);
linker_file_register_sysctls(lf, false);
linker_file_sysinit(lf);
lf->flags |= LINKER_FILE_LINKED;
/*
* If all of the modules in this file failed
* to load, unload the file and return an
* error of ENOEXEC.
*/
if (modules && TAILQ_EMPTY(&lf->modules)) {
linker_file_unload(lf, LINKER_UNLOAD_FORCE);
return (ENOEXEC);
}
linker_file_enable_sysctls(lf);
EVENTHANDLER_INVOKE(kld_load, lf);
*result = lf;
return (0);
}
}
/*
* Less than ideal, but tells the user whether it failed to load or
* the module was not found.
*/
if (foundfile) {
/*
* If the file type has not been recognized by the last try
* printout a message before to fail.
*/
if (error == ENOSYS)
printf("%s: %s - unsupported file type\n",
__func__, filename);
/*
* Format not recognized or otherwise unloadable.
* When loading a module that is statically built into
* the kernel EEXIST percolates back up as the return
* value. Preserve this so that apps like sysinstall
* can recognize this special case and not post bogus
* dialog boxes.
*/
if (error != EEXIST)
error = ENOEXEC;
} else
error = ENOENT; /* Nothing found */
return (error);
}
int
linker_reference_module(const char *modname, struct mod_depend *verinfo,
linker_file_t *result)
{
modlist_t mod;
int error;
sx_xlock(&kld_sx);
if ((mod = modlist_lookup2(modname, verinfo)) != NULL) {
*result = mod->container;
(*result)->refs++;
sx_xunlock(&kld_sx);
return (0);
}
error = linker_load_module(NULL, modname, NULL, verinfo, result);
sx_xunlock(&kld_sx);
return (error);
}
int
linker_release_module(const char *modname, struct mod_depend *verinfo,
linker_file_t lf)
{
modlist_t mod;
int error;
sx_xlock(&kld_sx);
if (lf == NULL) {
KASSERT(modname != NULL,
("linker_release_module: no file or name"));
mod = modlist_lookup2(modname, verinfo);
if (mod == NULL) {
sx_xunlock(&kld_sx);
return (ESRCH);
}
lf = mod->container;
} else
KASSERT(modname == NULL && verinfo == NULL,
("linker_release_module: both file and name"));
error = linker_file_unload(lf, LINKER_UNLOAD_NORMAL);
sx_xunlock(&kld_sx);
return (error);
}
static linker_file_t
linker_find_file_by_name(const char *filename)
{
linker_file_t lf;
char *koname;
koname = malloc(strlen(filename) + 4, M_LINKER, M_WAITOK);
sprintf(koname, "%s.ko", filename);
sx_assert(&kld_sx, SA_XLOCKED);
TAILQ_FOREACH(lf, &linker_files, link) {
if (strcmp(lf->filename, koname) == 0)
break;
if (strcmp(lf->filename, filename) == 0)
break;
}
free(koname, M_LINKER);
return (lf);
}
static linker_file_t
linker_find_file_by_id(int fileid)
{
linker_file_t lf;
sx_assert(&kld_sx, SA_XLOCKED);
TAILQ_FOREACH(lf, &linker_files, link)
if (lf->id == fileid && lf->flags & LINKER_FILE_LINKED)
break;
return (lf);
}
int
linker_file_foreach(linker_predicate_t *predicate, void *context)
{
linker_file_t lf;
int retval = 0;
sx_xlock(&kld_sx);
TAILQ_FOREACH(lf, &linker_files, link) {
retval = predicate(lf, context);
if (retval != 0)
break;
}
sx_xunlock(&kld_sx);
return (retval);
}
linker_file_t
linker_make_file(const char *pathname, linker_class_t lc)
{
linker_file_t lf;
const char *filename;
if (!cold)
sx_assert(&kld_sx, SA_XLOCKED);
filename = linker_basename(pathname);
KLD_DPF(FILE, ("linker_make_file: new file, filename='%s' for pathname='%s'\n", filename, pathname));
lf = (linker_file_t)kobj_create((kobj_class_t)lc, M_LINKER, M_WAITOK);
if (lf == NULL)
return (NULL);
lf->ctors_addr = 0;
lf->ctors_size = 0;
lf->dtors_addr = 0;
lf->dtors_size = 0;
lf->refs = 1;
lf->userrefs = 0;
lf->flags = 0;
lf->filename = strdup(filename, M_LINKER);
lf->pathname = strdup(pathname, M_LINKER);
LINKER_GET_NEXT_FILE_ID(lf->id);
lf->ndeps = 0;
lf->deps = NULL;
lf->loadcnt = ++loadcnt;
#ifdef __arm__
lf->exidx_addr = 0;
lf->exidx_size = 0;
#endif
STAILQ_INIT(&lf->common);
TAILQ_INIT(&lf->modules);
TAILQ_INSERT_TAIL(&linker_files, lf, link);
return (lf);
}
int
linker_file_unload(linker_file_t file, int flags)
{
module_t mod, next;
modlist_t ml, nextml;
struct common_symbol *cp;
int error, i;
/* Refuse to unload modules if securelevel raised. */
if (prison0.pr_securelevel > 0)
return (EPERM);
sx_assert(&kld_sx, SA_XLOCKED);
KLD_DPF(FILE, ("linker_file_unload: lf->refs=%d\n", file->refs));
/* Easy case of just dropping a reference. */
if (file->refs > 1) {
file->refs--;
return (0);
}
/* Give eventhandlers a chance to prevent the unload. */
error = 0;
EVENTHANDLER_INVOKE(kld_unload_try, file, &error);
if (error != 0)
return (EBUSY);
KLD_DPF(FILE, ("linker_file_unload: file is unloading,"
" informing modules\n"));
/*
* Quiesce all the modules to give them a chance to veto the unload.
*/
MOD_SLOCK;
for (mod = TAILQ_FIRST(&file->modules); mod;
mod = module_getfnext(mod)) {
error = module_quiesce(mod);
if (error != 0 && flags != LINKER_UNLOAD_FORCE) {
KLD_DPF(FILE, ("linker_file_unload: module %s"
" vetoed unload\n", module_getname(mod)));
/*
* XXX: Do we need to tell all the quiesced modules
* that they can resume work now via a new module
* event?
*/
MOD_SUNLOCK;
return (error);
}
}
MOD_SUNLOCK;
/*
* Inform any modules associated with this file that they are
* being unloaded.
*/
MOD_XLOCK;
for (mod = TAILQ_FIRST(&file->modules); mod; mod = next) {
next = module_getfnext(mod);
MOD_XUNLOCK;
/*
* Give the module a chance to veto the unload.
*/
if ((error = module_unload(mod)) != 0) {
#ifdef KLD_DEBUG
MOD_SLOCK;
KLD_DPF(FILE, ("linker_file_unload: module %s"
" failed unload\n", module_getname(mod)));
MOD_SUNLOCK;
#endif
return (error);
}
MOD_XLOCK;
module_release(mod);
}
MOD_XUNLOCK;
TAILQ_FOREACH_SAFE(ml, &found_modules, link, nextml) {
if (ml->container == file) {
TAILQ_REMOVE(&found_modules, ml, link);
free(ml, M_LINKER);
}
}
/*
* Don't try to run SYSUNINITs if we are unloaded due to a
* link error.
*/
if (file->flags & LINKER_FILE_LINKED) {
file->flags &= ~LINKER_FILE_LINKED;
linker_file_unregister_sysctls(file);
linker_file_sysuninit(file);
}
TAILQ_REMOVE(&linker_files, file, link);
if (file->deps) {
for (i = 0; i < file->ndeps; i++)
linker_file_unload(file->deps[i], flags);
free(file->deps, M_LINKER);
file->deps = NULL;
}
while ((cp = STAILQ_FIRST(&file->common)) != NULL) {
STAILQ_REMOVE_HEAD(&file->common, link);
free(cp, M_LINKER);
}
LINKER_UNLOAD(file);
EVENTHANDLER_INVOKE(kld_unload, file->filename, file->address,
file->size);
if (file->filename) {
free(file->filename, M_LINKER);
file->filename = NULL;
}
if (file->pathname) {
free(file->pathname, M_LINKER);
file->pathname = NULL;
}
kobj_delete((kobj_t) file, M_LINKER);
return (0);
}
int
linker_ctf_get(linker_file_t file, linker_ctf_t *lc)
{
return (LINKER_CTF_GET(file, lc));
}
static int
linker_file_add_dependency(linker_file_t file, linker_file_t dep)
{
linker_file_t *newdeps;
sx_assert(&kld_sx, SA_XLOCKED);
file->deps = realloc(file->deps, (file->ndeps + 1) * sizeof(*newdeps),
M_LINKER, M_WAITOK | M_ZERO);
file->deps[file->ndeps] = dep;
file->ndeps++;
KLD_DPF(FILE, ("linker_file_add_dependency:"
" adding %s as dependency for %s\n",
dep->filename, file->filename));
return (0);
}
/*
* Locate a linker set and its contents. This is a helper function to avoid
* linker_if.h exposure elsewhere. Note: firstp and lastp are really void **.
* This function is used in this file so we can avoid having lots of (void **)
* casts.
*/
int
linker_file_lookup_set(linker_file_t file, const char *name,
void *firstp, void *lastp, int *countp)
{
sx_assert(&kld_sx, SA_LOCKED);
return (LINKER_LOOKUP_SET(file, name, firstp, lastp, countp));
}
/*
* List all functions in a file.
*/
int
linker_file_function_listall(linker_file_t lf,
linker_function_nameval_callback_t callback_func, void *arg)
{
return (LINKER_EACH_FUNCTION_NAMEVAL(lf, callback_func, arg));
}
caddr_t
linker_file_lookup_symbol(linker_file_t file, const char *name, int deps)
{
caddr_t sym;
int locked;
locked = sx_xlocked(&kld_sx);
if (!locked)
sx_xlock(&kld_sx);
sym = linker_file_lookup_symbol_internal(file, name, deps);
if (!locked)
sx_xunlock(&kld_sx);
return (sym);
}
static caddr_t
linker_file_lookup_symbol_internal(linker_file_t file, const char *name,
int deps)
{
c_linker_sym_t sym;
linker_symval_t symval;
caddr_t address;
size_t common_size = 0;
int i;
sx_assert(&kld_sx, SA_XLOCKED);
KLD_DPF(SYM, ("linker_file_lookup_symbol: file=%p, name=%s, deps=%d\n",
file, name, deps));
if (LINKER_LOOKUP_SYMBOL(file, name, &sym) == 0) {
LINKER_SYMBOL_VALUES(file, sym, &symval);
if (symval.value == 0)
/*
* For commons, first look them up in the
* dependencies and only allocate space if not found
* there.
*/
common_size = symval.size;
else {
KLD_DPF(SYM, ("linker_file_lookup_symbol: symbol"
".value=%p\n", symval.value));
return (symval.value);
}
}
if (deps) {
for (i = 0; i < file->ndeps; i++) {
address = linker_file_lookup_symbol_internal(
file->deps[i], name, 0);
if (address) {
KLD_DPF(SYM, ("linker_file_lookup_symbol:"
" deps value=%p\n", address));
return (address);
}
}
}
if (common_size > 0) {
/*
* This is a common symbol which was not found in the
* dependencies. We maintain a simple common symbol table in
* the file object.
*/
struct common_symbol *cp;
STAILQ_FOREACH(cp, &file->common, link) {
if (strcmp(cp->name, name) == 0) {
KLD_DPF(SYM, ("linker_file_lookup_symbol:"
" old common value=%p\n", cp->address));
return (cp->address);
}
}
/*
* Round the symbol size up to align.
*/
common_size = (common_size + sizeof(int) - 1) & -sizeof(int);
cp = malloc(sizeof(struct common_symbol)
+ common_size + strlen(name) + 1, M_LINKER,
M_WAITOK | M_ZERO);
cp->address = (caddr_t)(cp + 1);
cp->name = cp->address + common_size;
strcpy(cp->name, name);
bzero(cp->address, common_size);
STAILQ_INSERT_TAIL(&file->common, cp, link);
KLD_DPF(SYM, ("linker_file_lookup_symbol: new common"
" value=%p\n", cp->address));
return (cp->address);
}
KLD_DPF(SYM, ("linker_file_lookup_symbol: fail\n"));
return (0);
}
/*
* Both DDB and stack(9) rely on the kernel linker to provide forward and
* backward lookup of symbols. However, DDB and sometimes stack(9) need to
* do this in a lockfree manner. We provide a set of internal helper
* routines to perform these operations without locks, and then wrappers that
* optionally lock.
*
* linker_debug_lookup() is ifdef DDB as currently it's only used by DDB.
*/
#ifdef DDB
static int
linker_debug_lookup(const char *symstr, c_linker_sym_t *sym)
{
linker_file_t lf;
TAILQ_FOREACH(lf, &linker_files, link) {
if (LINKER_LOOKUP_SYMBOL(lf, symstr, sym) == 0)
return (0);
}
return (ENOENT);
}
#endif
static int
linker_debug_search_symbol(caddr_t value, c_linker_sym_t *sym, long *diffp)
{
linker_file_t lf;
c_linker_sym_t best, es;
u_long diff, bestdiff, off;
best = 0;
off = (uintptr_t)value;
bestdiff = off;
TAILQ_FOREACH(lf, &linker_files, link) {
if (LINKER_SEARCH_SYMBOL(lf, value, &es, &diff) != 0)
continue;
if (es != 0 && diff < bestdiff) {
best = es;
bestdiff = diff;
}
if (bestdiff == 0)
break;
}
if (best) {
*sym = best;
*diffp = bestdiff;
return (0);
} else {
*sym = 0;
*diffp = off;
return (ENOENT);
}
}
static int
linker_debug_symbol_values(c_linker_sym_t sym, linker_symval_t *symval)
{
linker_file_t lf;
TAILQ_FOREACH(lf, &linker_files, link) {
if (LINKER_SYMBOL_VALUES(lf, sym, symval) == 0)
return (0);
}
return (ENOENT);
}
static int
linker_debug_search_symbol_name(caddr_t value, char *buf, u_int buflen,
long *offset)
{
linker_symval_t symval;
c_linker_sym_t sym;
int error;
*offset = 0;
error = linker_debug_search_symbol(value, &sym, offset);
if (error)
return (error);
error = linker_debug_symbol_values(sym, &symval);
if (error)
return (error);
strlcpy(buf, symval.name, buflen);
return (0);
}
/*
* DDB Helpers. DDB has to look across multiple files with their own symbol
* tables and string tables.
*
* Note that we do not obey list locking protocols here. We really don't need
* DDB to hang because somebody's got the lock held. We'll take the chance
* that the files list is inconsistent instead.
*/
#ifdef DDB
int
linker_ddb_lookup(const char *symstr, c_linker_sym_t *sym)
{
return (linker_debug_lookup(symstr, sym));
}
#endif
int
linker_ddb_search_symbol(caddr_t value, c_linker_sym_t *sym, long *diffp)
{
return (linker_debug_search_symbol(value, sym, diffp));
}
int
linker_ddb_symbol_values(c_linker_sym_t sym, linker_symval_t *symval)
{
return (linker_debug_symbol_values(sym, symval));
}
int
linker_ddb_search_symbol_name(caddr_t value, char *buf, u_int buflen,
long *offset)
{
return (linker_debug_search_symbol_name(value, buf, buflen, offset));
}
/*
* stack(9) helper for non-debugging environemnts. Unlike DDB helpers, we do
* obey locking protocols, and offer a significantly less complex interface.
*/
int
linker_search_symbol_name_flags(caddr_t value, char *buf, u_int buflen,
long *offset, int flags)
{
int error;
KASSERT((flags & (M_NOWAIT | M_WAITOK)) != 0 &&
(flags & (M_NOWAIT | M_WAITOK)) != (M_NOWAIT | M_WAITOK),
("%s: bad flags: 0x%x", __func__, flags));
if (flags & M_NOWAIT) {
if (!sx_try_slock(&kld_sx))
return (EWOULDBLOCK);
} else
sx_slock(&kld_sx);
error = linker_debug_search_symbol_name(value, buf, buflen, offset);
sx_sunlock(&kld_sx);
return (error);
}
int
linker_search_symbol_name(caddr_t value, char *buf, u_int buflen,
long *offset)
{
return (linker_search_symbol_name_flags(value, buf, buflen, offset,
M_WAITOK));
}
int
linker_kldload_busy(int flags)
{
int error;
MPASS((flags & ~(LINKER_UB_UNLOCK | LINKER_UB_LOCKED |
LINKER_UB_PCATCH)) == 0);
if ((flags & LINKER_UB_LOCKED) != 0)
sx_assert(&kld_sx, SA_XLOCKED);
if ((flags & LINKER_UB_LOCKED) == 0)
sx_xlock(&kld_sx);
while (kld_busy) {
error = sx_sleep(&kld_busy, &kld_sx,
(flags & LINKER_UB_PCATCH) != 0 ? PCATCH : 0,
"kldbusy", 0);
if (error != 0) {
if ((flags & LINKER_UB_UNLOCK) != 0)
sx_xunlock(&kld_sx);
return (error);
}
}
kld_busy = true;
if ((flags & LINKER_UB_UNLOCK) != 0)
sx_xunlock(&kld_sx);
return (0);
}
void
linker_kldload_unbusy(int flags)
{
MPASS((flags & ~LINKER_UB_LOCKED) == 0);
if ((flags & LINKER_UB_LOCKED) != 0)
sx_assert(&kld_sx, SA_XLOCKED);
if ((flags & LINKER_UB_LOCKED) == 0)
sx_xlock(&kld_sx);
MPASS(kld_busy);
kld_busy = false;
wakeup(&kld_busy);
sx_xunlock(&kld_sx);
}
/*
* Syscalls.
*/
int
kern_kldload(struct thread *td, const char *file, int *fileid)
{
const char *kldname, *modname;
linker_file_t lf;
int error;
if ((error = securelevel_gt(td->td_ucred, 0)) != 0)
return (error);
if ((error = priv_check(td, PRIV_KLD_LOAD)) != 0)
return (error);
/*
* If file does not contain a qualified name or any dot in it
* (kldname.ko, or kldname.ver.ko) treat it as an interface
* name.
*/
if (strchr(file, '/') || strchr(file, '.')) {
kldname = file;
modname = NULL;
} else {
kldname = NULL;
modname = file;
}
error = linker_kldload_busy(LINKER_UB_PCATCH);
if (error != 0) {
sx_xunlock(&kld_sx);
return (error);
}
/*
* It is possible that kldloaded module will attach a new ifnet,
* so vnet context must be set when this ocurs.
*/
CURVNET_SET(TD_TO_VNET(td));
error = linker_load_module(kldname, modname, NULL, NULL, &lf);
CURVNET_RESTORE();
if (error == 0) {
lf->userrefs++;
if (fileid != NULL)
*fileid = lf->id;
}
linker_kldload_unbusy(LINKER_UB_LOCKED);
return (error);
}
int
sys_kldload(struct thread *td, struct kldload_args *uap)
{
char *pathname = NULL;
int error, fileid;
td->td_retval[0] = -1;
pathname = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
error = copyinstr(uap->file, pathname, MAXPATHLEN, NULL);
if (error == 0) {
error = kern_kldload(td, pathname, &fileid);
if (error == 0)
td->td_retval[0] = fileid;
}
free(pathname, M_TEMP);
return (error);
}
int
kern_kldunload(struct thread *td, int fileid, int flags)
{
linker_file_t lf;
int error = 0;
if ((error = securelevel_gt(td->td_ucred, 0)) != 0)
return (error);
if ((error = priv_check(td, PRIV_KLD_UNLOAD)) != 0)
return (error);
error = linker_kldload_busy(LINKER_UB_PCATCH);
if (error != 0) {
sx_xunlock(&kld_sx);
return (error);
}
CURVNET_SET(TD_TO_VNET(td));
lf = linker_find_file_by_id(fileid);
if (lf) {
KLD_DPF(FILE, ("kldunload: lf->userrefs=%d\n", lf->userrefs));
if (lf->userrefs == 0) {
/*
* XXX: maybe LINKER_UNLOAD_FORCE should override ?
*/
printf("kldunload: attempt to unload file that was"
" loaded by the kernel\n");
error = EBUSY;
} else {
lf->userrefs--;
error = linker_file_unload(lf, flags);
if (error)
lf->userrefs++;
}
} else
error = ENOENT;
CURVNET_RESTORE();
linker_kldload_unbusy(LINKER_UB_LOCKED);
return (error);
}
int
sys_kldunload(struct thread *td, struct kldunload_args *uap)
{
return (kern_kldunload(td, uap->fileid, LINKER_UNLOAD_NORMAL));
}
int
sys_kldunloadf(struct thread *td, struct kldunloadf_args *uap)
{
if (uap->flags != LINKER_UNLOAD_NORMAL &&
uap->flags != LINKER_UNLOAD_FORCE)
return (EINVAL);
return (kern_kldunload(td, uap->fileid, uap->flags));
}
int
sys_kldfind(struct thread *td, struct kldfind_args *uap)
{
char *pathname;
const char *filename;
linker_file_t lf;
int error;
#ifdef MAC
error = mac_kld_check_stat(td->td_ucred);
if (error)
return (error);
#endif
td->td_retval[0] = -1;
pathname = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
if ((error = copyinstr(uap->file, pathname, MAXPATHLEN, NULL)) != 0)
goto out;
filename = linker_basename(pathname);
sx_xlock(&kld_sx);
lf = linker_find_file_by_name(filename);
if (lf)
td->td_retval[0] = lf->id;
else
error = ENOENT;
sx_xunlock(&kld_sx);
out:
free(pathname, M_TEMP);
return (error);
}
int
sys_kldnext(struct thread *td, struct kldnext_args *uap)
{
linker_file_t lf;
int error = 0;
#ifdef MAC
error = mac_kld_check_stat(td->td_ucred);
if (error)
return (error);
#endif
sx_xlock(&kld_sx);
if (uap->fileid == 0)
lf = TAILQ_FIRST(&linker_files);
else {
lf = linker_find_file_by_id(uap->fileid);
if (lf == NULL) {
error = ENOENT;
goto out;
}
lf = TAILQ_NEXT(lf, link);
}
/* Skip partially loaded files. */
while (lf != NULL && !(lf->flags & LINKER_FILE_LINKED))
lf = TAILQ_NEXT(lf, link);
if (lf)
td->td_retval[0] = lf->id;
else
td->td_retval[0] = 0;
out:
sx_xunlock(&kld_sx);
return (error);
}
int
sys_kldstat(struct thread *td, struct kldstat_args *uap)
{
struct kld_file_stat *stat;
int error, version;
/*
* Check the version of the user's structure.
*/
if ((error = copyin(&uap->stat->version, &version, sizeof(version)))
!= 0)
return (error);
if (version != sizeof(struct kld_file_stat_1) &&
version != sizeof(struct kld_file_stat))
return (EINVAL);
stat = malloc(sizeof(*stat), M_TEMP, M_WAITOK | M_ZERO);
error = kern_kldstat(td, uap->fileid, stat);
if (error == 0)
error = copyout(stat, uap->stat, version);
free(stat, M_TEMP);
return (error);
}
int
kern_kldstat(struct thread *td, int fileid, struct kld_file_stat *stat)
{
linker_file_t lf;
int namelen;
#ifdef MAC
int error;
error = mac_kld_check_stat(td->td_ucred);
if (error)
return (error);
#endif
sx_xlock(&kld_sx);
lf = linker_find_file_by_id(fileid);
if (lf == NULL) {
sx_xunlock(&kld_sx);
return (ENOENT);
}
/* Version 1 fields: */
namelen = strlen(lf->filename) + 1;
if (namelen > sizeof(stat->name))
namelen = sizeof(stat->name);
bcopy(lf->filename, &stat->name[0], namelen);
stat->refs = lf->refs;
stat->id = lf->id;
stat->address = lf->address;
stat->size = lf->size;
/* Version 2 fields: */
namelen = strlen(lf->pathname) + 1;
if (namelen > sizeof(stat->pathname))
namelen = sizeof(stat->pathname);
bcopy(lf->pathname, &stat->pathname[0], namelen);
sx_xunlock(&kld_sx);
td->td_retval[0] = 0;
return (0);
}
#ifdef DDB
DB_COMMAND(kldstat, db_kldstat)
{
linker_file_t lf;
#define POINTER_WIDTH ((int)(sizeof(void *) * 2 + 2))
db_printf("Id Refs Address%*c Size Name\n", POINTER_WIDTH - 7, ' ');
#undef POINTER_WIDTH
TAILQ_FOREACH(lf, &linker_files, link) {
if (db_pager_quit)
return;
db_printf("%2d %4d %p %-8zx %s\n", lf->id, lf->refs,
lf->address, lf->size, lf->filename);
}
}
#endif /* DDB */
int
sys_kldfirstmod(struct thread *td, struct kldfirstmod_args *uap)
{
linker_file_t lf;
module_t mp;
int error = 0;
#ifdef MAC
error = mac_kld_check_stat(td->td_ucred);
if (error)
return (error);
#endif
sx_xlock(&kld_sx);
lf = linker_find_file_by_id(uap->fileid);
if (lf) {
MOD_SLOCK;
mp = TAILQ_FIRST(&lf->modules);
if (mp != NULL)
td->td_retval[0] = module_getid(mp);
else
td->td_retval[0] = 0;
MOD_SUNLOCK;
} else
error = ENOENT;
sx_xunlock(&kld_sx);
return (error);
}
int
sys_kldsym(struct thread *td, struct kldsym_args *uap)
{
char *symstr = NULL;
c_linker_sym_t sym;
linker_symval_t symval;
linker_file_t lf;
struct kld_sym_lookup lookup;
int error = 0;
#ifdef MAC
error = mac_kld_check_stat(td->td_ucred);
if (error)
return (error);
#endif
if ((error = copyin(uap->data, &lookup, sizeof(lookup))) != 0)
return (error);
if (lookup.version != sizeof(lookup) ||
uap->cmd != KLDSYM_LOOKUP)
return (EINVAL);
symstr = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
if ((error = copyinstr(lookup.symname, symstr, MAXPATHLEN, NULL)) != 0)
goto out;
sx_xlock(&kld_sx);
if (uap->fileid != 0) {
lf = linker_find_file_by_id(uap->fileid);
if (lf == NULL)
error = ENOENT;
else if (LINKER_LOOKUP_SYMBOL(lf, symstr, &sym) == 0 &&
LINKER_SYMBOL_VALUES(lf, sym, &symval) == 0) {
lookup.symvalue = (uintptr_t) symval.value;
lookup.symsize = symval.size;
error = copyout(&lookup, uap->data, sizeof(lookup));
} else
error = ENOENT;
} else {
TAILQ_FOREACH(lf, &linker_files, link) {
if (LINKER_LOOKUP_SYMBOL(lf, symstr, &sym) == 0 &&
LINKER_SYMBOL_VALUES(lf, sym, &symval) == 0) {
lookup.symvalue = (uintptr_t)symval.value;
lookup.symsize = symval.size;
error = copyout(&lookup, uap->data,
sizeof(lookup));
break;
}
}
if (lf == NULL)
error = ENOENT;
}
sx_xunlock(&kld_sx);
out:
free(symstr, M_TEMP);
return (error);
}
/*
* Preloaded module support
*/
static modlist_t
modlist_lookup(const char *name, int ver)
{
modlist_t mod;
TAILQ_FOREACH(mod, &found_modules, link) {
if (strcmp(mod->name, name) == 0 &&
(ver == 0 || mod->version == ver))
return (mod);
}
return (NULL);
}
static modlist_t
modlist_lookup2(const char *name, const struct mod_depend *verinfo)
{
modlist_t mod, bestmod;
int ver;
if (verinfo == NULL)
return (modlist_lookup(name, 0));
bestmod = NULL;
TAILQ_FOREACH(mod, &found_modules, link) {
if (strcmp(mod->name, name) != 0)
continue;
ver = mod->version;
if (ver == verinfo->md_ver_preferred)
return (mod);
if (ver >= verinfo->md_ver_minimum &&
ver <= verinfo->md_ver_maximum &&
(bestmod == NULL || ver > bestmod->version))
bestmod = mod;
}
return (bestmod);
}
static modlist_t
modlist_newmodule(const char *modname, int version, linker_file_t container)
{
modlist_t mod;
mod = malloc(sizeof(struct modlist), M_LINKER, M_NOWAIT | M_ZERO);
if (mod == NULL)
panic("no memory for module list");
mod->container = container;
mod->name = modname;
mod->version = version;
TAILQ_INSERT_TAIL(&found_modules, mod, link);
return (mod);
}
static void
linker_addmodules(linker_file_t lf, struct mod_metadata **start,
struct mod_metadata **stop, int preload)
{
struct mod_metadata *mp, **mdp;
const char *modname;
int ver;
for (mdp = start; mdp < stop; mdp++) {
mp = *mdp;
if (mp->md_type != MDT_VERSION)
continue;
modname = mp->md_cval;
ver = ((const struct mod_version *)mp->md_data)->mv_version;
if (modlist_lookup(modname, ver) != NULL) {
printf("module %s already present!\n", modname);
/* XXX what can we do? this is a build error. :-( */
continue;
}
modlist_newmodule(modname, ver, lf);
}
}
static void
linker_preload(void *arg)
{
caddr_t modptr;
const char *modname, *nmodname;
char *modtype;
linker_file_t lf, nlf;
linker_class_t lc;
int error;
linker_file_list_t loaded_files;
linker_file_list_t depended_files;
struct mod_metadata *mp, *nmp;
struct mod_metadata **start, **stop, **mdp, **nmdp;
const struct mod_depend *verinfo;
int nver;
int resolves;
modlist_t mod;
struct sysinit **si_start, **si_stop;
TAILQ_INIT(&loaded_files);
TAILQ_INIT(&depended_files);
TAILQ_INIT(&found_modules);
error = 0;
modptr = NULL;
sx_xlock(&kld_sx);
while ((modptr = preload_search_next_name(modptr)) != NULL) {
modname = (char *)preload_search_info(modptr, MODINFO_NAME);
modtype = (char *)preload_search_info(modptr, MODINFO_TYPE);
if (modname == NULL) {
printf("Preloaded module at %p does not have a"
" name!\n", modptr);
continue;
}
if (modtype == NULL) {
printf("Preloaded module at %p does not have a type!\n",
modptr);
continue;
}
if (bootverbose)
printf("Preloaded %s \"%s\" at %p.\n", modtype, modname,
modptr);
lf = NULL;
TAILQ_FOREACH(lc, &classes, link) {
error = LINKER_LINK_PRELOAD(lc, modname, &lf);
if (!error)
break;
lf = NULL;
}
if (lf)
TAILQ_INSERT_TAIL(&loaded_files, lf, loaded);
}
/*
* First get a list of stuff in the kernel.
*/
if (linker_file_lookup_set(linker_kernel_file, MDT_SETNAME, &start,
&stop, NULL) == 0)
linker_addmodules(linker_kernel_file, start, stop, 1);
/*
* This is a once-off kinky bubble sort to resolve relocation
* dependency requirements.
*/
restart:
TAILQ_FOREACH(lf, &loaded_files, loaded) {
error = linker_file_lookup_set(lf, MDT_SETNAME, &start,
&stop, NULL);
/*
* First, look to see if we would successfully link with this
* stuff.
*/
resolves = 1; /* unless we know otherwise */
if (!error) {
for (mdp = start; mdp < stop; mdp++) {
mp = *mdp;
if (mp->md_type != MDT_DEPEND)
continue;
modname = mp->md_cval;
verinfo = mp->md_data;
for (nmdp = start; nmdp < stop; nmdp++) {
nmp = *nmdp;
if (nmp->md_type != MDT_VERSION)
continue;
nmodname = nmp->md_cval;
if (strcmp(modname, nmodname) == 0)
break;
}
if (nmdp < stop) /* it's a self reference */
continue;
/*
* ok, the module isn't here yet, we
* are not finished
*/
if (modlist_lookup2(modname, verinfo) == NULL)
resolves = 0;
}
}
/*
* OK, if we found our modules, we can link. So, "provide"
* the modules inside and add it to the end of the link order
* list.
*/
if (resolves) {
if (!error) {
for (mdp = start; mdp < stop; mdp++) {
mp = *mdp;
if (mp->md_type != MDT_VERSION)
continue;
modname = mp->md_cval;
nver = ((const struct mod_version *)
mp->md_data)->mv_version;
if (modlist_lookup(modname,
nver) != NULL) {
printf("module %s already"
" present!\n", modname);
TAILQ_REMOVE(&loaded_files,
lf, loaded);
linker_file_unload(lf,
LINKER_UNLOAD_FORCE);
/* we changed tailq next ptr */
goto restart;
}
modlist_newmodule(modname, nver, lf);
}
}
TAILQ_REMOVE(&loaded_files, lf, loaded);
TAILQ_INSERT_TAIL(&depended_files, lf, loaded);
/*
* Since we provided modules, we need to restart the
* sort so that the previous files that depend on us
* have a chance. Also, we've busted the tailq next
* pointer with the REMOVE.
*/
goto restart;
}
}
/*
* At this point, we check to see what could not be resolved..
*/
while ((lf = TAILQ_FIRST(&loaded_files)) != NULL) {
TAILQ_REMOVE(&loaded_files, lf, loaded);
printf("KLD file %s is missing dependencies\n", lf->filename);
linker_file_unload(lf, LINKER_UNLOAD_FORCE);
}
/*
* We made it. Finish off the linking in the order we determined.
*/
TAILQ_FOREACH_SAFE(lf, &depended_files, loaded, nlf) {
if (linker_kernel_file) {
linker_kernel_file->refs++;
error = linker_file_add_dependency(lf,
linker_kernel_file);
if (error)
panic("cannot add dependency");
}
error = linker_file_lookup_set(lf, MDT_SETNAME, &start,
&stop, NULL);
if (!error) {
for (mdp = start; mdp < stop; mdp++) {
mp = *mdp;
if (mp->md_type != MDT_DEPEND)
continue;
modname = mp->md_cval;
verinfo = mp->md_data;
mod = modlist_lookup2(modname, verinfo);
if (mod == NULL) {
printf("KLD file %s - cannot find "
"dependency \"%s\"\n",
lf->filename, modname);
goto fail;
}
/* Don't count self-dependencies */
if (lf == mod->container)
continue;
mod->container->refs++;
error = linker_file_add_dependency(lf,
mod->container);
if (error)
panic("cannot add dependency");
}
}
/*
* Now do relocation etc using the symbol search paths
* established by the dependencies
*/
error = LINKER_LINK_PRELOAD_FINISH(lf);
if (error) {
printf("KLD file %s - could not finalize loading\n",
lf->filename);
goto fail;
}
linker_file_register_modules(lf);
if (!TAILQ_EMPTY(&lf->modules))
lf->flags |= LINKER_FILE_MODULES;
if (linker_file_lookup_set(lf, "sysinit_set", &si_start,
&si_stop, NULL) == 0)
sysinit_add(si_start, si_stop);
linker_file_register_sysctls(lf, true);
lf->flags |= LINKER_FILE_LINKED;
continue;
fail:
TAILQ_REMOVE(&depended_files, lf, loaded);
linker_file_unload(lf, LINKER_UNLOAD_FORCE);
}
sx_xunlock(&kld_sx);
/* woohoo! we made it! */
}
SYSINIT(preload, SI_SUB_KLD, SI_ORDER_MIDDLE, linker_preload, NULL);
/*
* Handle preload files that failed to load any modules.
*/
static void
linker_preload_finish(void *arg)
{
linker_file_t lf, nlf;
sx_xlock(&kld_sx);
TAILQ_FOREACH_SAFE(lf, &linker_files, link, nlf) {
/*
* If all of the modules in this file failed to load, unload
* the file and return an error of ENOEXEC. (Parity with
* linker_load_file.)
*/
if ((lf->flags & LINKER_FILE_MODULES) != 0 &&
TAILQ_EMPTY(&lf->modules)) {
linker_file_unload(lf, LINKER_UNLOAD_FORCE);
continue;
}
lf->flags &= ~LINKER_FILE_MODULES;
lf->userrefs++; /* so we can (try to) kldunload it */
}
sx_xunlock(&kld_sx);
}
/*
* Attempt to run after all DECLARE_MODULE SYSINITs. Unfortunately they can be
* scheduled at any subsystem and order, so run this as late as possible. init
* becomes runnable in SI_SUB_KTHREAD_INIT, so go slightly before that.
*/
SYSINIT(preload_finish, SI_SUB_KTHREAD_INIT - 100, SI_ORDER_MIDDLE,
linker_preload_finish, NULL);
/*
* Search for a not-loaded module by name.
*
* Modules may be found in the following locations:
*
* - preloaded (result is just the module name) - on disk (result is full path
* to module)
*
* If the module name is qualified in any way (contains path, etc.) the we
* simply return a copy of it.
*
* The search path can be manipulated via sysctl. Note that we use the ';'
* character as a separator to be consistent with the bootloader.
*/
static char linker_hintfile[] = "linker.hints";
static char linker_path[MAXPATHLEN] = "/boot/kernel;/boot/modules";
SYSCTL_STRING(_kern, OID_AUTO, module_path, CTLFLAG_RWTUN, linker_path,
sizeof(linker_path), "module load search path");
TUNABLE_STR("module_path", linker_path, sizeof(linker_path));
static const char * const linker_ext_list[] = {
"",
".ko",
NULL
};
/*
* Check if file actually exists either with or without extension listed in
* the linker_ext_list. (probably should be generic for the rest of the
* kernel)
*/
static char *
linker_lookup_file(const char *path, int pathlen, const char *name,
int namelen, struct vattr *vap)
{
struct nameidata nd;
struct thread *td = curthread; /* XXX */
const char * const *cpp, *sep;
char *result;
int error, len, extlen, reclen, flags;
enum vtype type;
extlen = 0;
for (cpp = linker_ext_list; *cpp; cpp++) {
len = strlen(*cpp);
if (len > extlen)
extlen = len;
}
extlen++; /* trailing '\0' */
sep = (path[pathlen - 1] != '/') ? "/" : "";
reclen = pathlen + strlen(sep) + namelen + extlen + 1;
result = malloc(reclen, M_LINKER, M_WAITOK);
for (cpp = linker_ext_list; *cpp; cpp++) {
snprintf(result, reclen, "%.*s%s%.*s%s", pathlen, path, sep,
namelen, name, *cpp);
/*
* Attempt to open the file, and return the path if
* we succeed and it's a regular file.
*/
NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, result, td);
flags = FREAD;
error = vn_open(&nd, &flags, 0, NULL);
if (error == 0) {
NDFREE(&nd, NDF_ONLY_PNBUF);
type = nd.ni_vp->v_type;
if (vap)
VOP_GETATTR(nd.ni_vp, vap, td->td_ucred);
VOP_UNLOCK(nd.ni_vp);
vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
if (type == VREG)
return (result);
}
}
free(result, M_LINKER);
return (NULL);
}
#define INT_ALIGN(base, ptr) ptr = \
(base) + roundup2((ptr) - (base), sizeof(int))
/*
* Lookup KLD which contains requested module in the "linker.hints" file. If
* version specification is available, then try to find the best KLD.
* Otherwise just find the latest one.
*/
static char *
linker_hints_lookup(const char *path, int pathlen, const char *modname,
int modnamelen, const struct mod_depend *verinfo)
{
struct thread *td = curthread; /* XXX */
struct ucred *cred = td ? td->td_ucred : NULL;
struct nameidata nd;
struct vattr vattr, mattr;
const char *best, *sep;
u_char *hints = NULL;
u_char *cp, *recptr, *bufend, *result, *pathbuf;
int error, ival, bestver, *intp, found, flags, clen, blen;
ssize_t reclen;
result = NULL;
bestver = found = 0;
sep = (path[pathlen - 1] != '/') ? "/" : "";
reclen = imax(modnamelen, strlen(linker_hintfile)) + pathlen +
strlen(sep) + 1;
pathbuf = malloc(reclen, M_LINKER, M_WAITOK);
snprintf(pathbuf, reclen, "%.*s%s%s", pathlen, path, sep,
linker_hintfile);
NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, pathbuf, td);
flags = FREAD;
error = vn_open(&nd, &flags, 0, NULL);
if (error)
goto bad;
NDFREE(&nd, NDF_ONLY_PNBUF);
if (nd.ni_vp->v_type != VREG)
goto bad;
best = cp = NULL;
error = VOP_GETATTR(nd.ni_vp, &vattr, cred);
if (error)
goto bad;
/*
* XXX: we need to limit this number to some reasonable value
*/
if (vattr.va_size > LINKER_HINTS_MAX) {
printf("linker.hints file too large %ld\n", (long)vattr.va_size);
goto bad;
}
hints = malloc(vattr.va_size, M_TEMP, M_WAITOK);
error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)hints, vattr.va_size, 0,
UIO_SYSSPACE, IO_NODELOCKED, cred, NOCRED, &reclen, td);
if (error)
goto bad;
VOP_UNLOCK(nd.ni_vp);
vn_close(nd.ni_vp, FREAD, cred, td);
nd.ni_vp = NULL;
if (reclen != 0) {
printf("can't read %zd\n", reclen);
goto bad;
}
intp = (int *)hints;
ival = *intp++;
if (ival != LINKER_HINTS_VERSION) {
printf("linker.hints file version mismatch %d\n", ival);
goto bad;
}
bufend = hints + vattr.va_size;
recptr = (u_char *)intp;
clen = blen = 0;
while (recptr < bufend && !found) {
intp = (int *)recptr;
reclen = *intp++;
ival = *intp++;
cp = (char *)intp;
switch (ival) {
case MDT_VERSION:
clen = *cp++;
if (clen != modnamelen || bcmp(cp, modname, clen) != 0)
break;
cp += clen;
INT_ALIGN(hints, cp);
ival = *(int *)cp;
cp += sizeof(int);
clen = *cp++;
if (verinfo == NULL ||
ival == verinfo->md_ver_preferred) {
found = 1;
break;
}
if (ival >= verinfo->md_ver_minimum &&
ival <= verinfo->md_ver_maximum &&
ival > bestver) {
bestver = ival;
best = cp;
blen = clen;
}
break;
default:
break;
}
recptr += reclen + sizeof(int);
}
/*
* Finally check if KLD is in the place
*/
if (found)
result = linker_lookup_file(path, pathlen, cp, clen, &mattr);
else if (best)
result = linker_lookup_file(path, pathlen, best, blen, &mattr);
/*
* KLD is newer than hints file. What we should do now?
*/
if (result && timespeccmp(&mattr.va_mtime, &vattr.va_mtime, >))
printf("warning: KLD '%s' is newer than the linker.hints"
" file\n", result);
bad:
free(pathbuf, M_LINKER);
if (hints)
free(hints, M_TEMP);
if (nd.ni_vp != NULL) {
VOP_UNLOCK(nd.ni_vp);
vn_close(nd.ni_vp, FREAD, cred, td);
}
/*
* If nothing found or hints is absent - fallback to the old
* way by using "kldname[.ko]" as module name.
*/
if (!found && !bestver && result == NULL)
result = linker_lookup_file(path, pathlen, modname,
modnamelen, NULL);
return (result);
}
/*
* Lookup KLD which contains requested module in the all directories.
*/
static char *
linker_search_module(const char *modname, int modnamelen,
const struct mod_depend *verinfo)
{
char *cp, *ep, *result;
/*
* traverse the linker path
*/
for (cp = linker_path; *cp; cp = ep + 1) {
/* find the end of this component */
for (ep = cp; (*ep != 0) && (*ep != ';'); ep++);
result = linker_hints_lookup(cp, ep - cp, modname,
modnamelen, verinfo);
if (result != NULL)
return (result);
if (*ep == 0)
break;
}
return (NULL);
}
/*
* Search for module in all directories listed in the linker_path.
*/
static char *
linker_search_kld(const char *name)
{
char *cp, *ep, *result;
int len;
/* qualified at all? */
if (strchr(name, '/'))
return (strdup(name, M_LINKER));
/* traverse the linker path */
len = strlen(name);
for (ep = linker_path; *ep; ep++) {
cp = ep;
/* find the end of this component */
for (; *ep != 0 && *ep != ';'; ep++);
result = linker_lookup_file(cp, ep - cp, name, len, NULL);
if (result != NULL)
return (result);
}
return (NULL);
}
static const char *
linker_basename(const char *path)
{
const char *filename;
filename = strrchr(path, '/');
if (filename == NULL)
return path;
if (filename[1])
filename++;
return (filename);
}
#ifdef HWPMC_HOOKS
/*
* Inform hwpmc about the set of kernel modules currently loaded.
*/
void *
linker_hwpmc_list_objects(void)
{
linker_file_t lf;
struct pmckern_map_in *kobase;
int i, nmappings;
nmappings = 0;
sx_slock(&kld_sx);
TAILQ_FOREACH(lf, &linker_files, link)
nmappings++;
/* Allocate nmappings + 1 entries. */
kobase = malloc((nmappings + 1) * sizeof(struct pmckern_map_in),
M_LINKER, M_WAITOK | M_ZERO);
i = 0;
TAILQ_FOREACH(lf, &linker_files, link) {
/* Save the info for this linker file. */
kobase[i].pm_file = lf->filename;
kobase[i].pm_address = (uintptr_t)lf->address;
i++;
}
sx_sunlock(&kld_sx);
KASSERT(i > 0, ("linker_hpwmc_list_objects: no kernel objects?"));
/* The last entry of the malloced area comprises of all zeros. */
KASSERT(kobase[i].pm_file == NULL,
("linker_hwpmc_list_objects: last object not NULL"));
return ((void *)kobase);
}
#endif
/* check if root file system is not mounted */
static bool
linker_root_mounted(void)
{
struct pwd *pwd;
bool ret;
if (rootvnode == NULL)
return (false);
pwd = pwd_hold(curthread);
ret = pwd->pwd_rdir != NULL;
pwd_drop(pwd);
return (ret);
}
/*
* Find a file which contains given module and load it, if "parent" is not
* NULL, register a reference to it.
*/
static int
linker_load_module(const char *kldname, const char *modname,
struct linker_file *parent, const struct mod_depend *verinfo,
struct linker_file **lfpp)
{
linker_file_t lfdep;
const char *filename;
char *pathname;
int error;
sx_assert(&kld_sx, SA_XLOCKED);
if (modname == NULL) {
/*
* We have to load KLD
*/
KASSERT(verinfo == NULL, ("linker_load_module: verinfo"
" is not NULL"));
if (!linker_root_mounted())
return (ENXIO);
pathname = linker_search_kld(kldname);
} else {
if (modlist_lookup2(modname, verinfo) != NULL)
return (EEXIST);
if (!linker_root_mounted())
return (ENXIO);
if (kldname != NULL)
pathname = strdup(kldname, M_LINKER);
else
/*
* Need to find a KLD with required module
*/
pathname = linker_search_module(modname,
strlen(modname), verinfo);
}
if (pathname == NULL)
return (ENOENT);
/*
* Can't load more than one file with the same basename XXX:
* Actually it should be possible to have multiple KLDs with
* the same basename but different path because they can
* provide different versions of the same modules.
*/
filename = linker_basename(pathname);
if (linker_find_file_by_name(filename))
error = EEXIST;
else do {
error = linker_load_file(pathname, &lfdep);
if (error)
break;
if (modname && verinfo &&
modlist_lookup2(modname, verinfo) == NULL) {
linker_file_unload(lfdep, LINKER_UNLOAD_FORCE);
error = ENOENT;
break;
}
if (parent) {
error = linker_file_add_dependency(parent, lfdep);
if (error)
break;
}
if (lfpp)
*lfpp = lfdep;
} while (0);
free(pathname, M_LINKER);
return (error);
}
/*
* This routine is responsible for finding dependencies of userland initiated
* kldload(2)'s of files.
*/
int
linker_load_dependencies(linker_file_t lf)
{
linker_file_t lfdep;
struct mod_metadata **start, **stop, **mdp, **nmdp;
struct mod_metadata *mp, *nmp;
const struct mod_depend *verinfo;
modlist_t mod;
const char *modname, *nmodname;
int ver, error = 0;
/*
* All files are dependent on /kernel.
*/
sx_assert(&kld_sx, SA_XLOCKED);
if (linker_kernel_file) {
linker_kernel_file->refs++;
error = linker_file_add_dependency(lf, linker_kernel_file);
if (error)
return (error);
}
if (linker_file_lookup_set(lf, MDT_SETNAME, &start, &stop,
NULL) != 0)
return (0);
for (mdp = start; mdp < stop; mdp++) {
mp = *mdp;
if (mp->md_type != MDT_VERSION)
continue;
modname = mp->md_cval;
ver = ((const struct mod_version *)mp->md_data)->mv_version;
mod = modlist_lookup(modname, ver);
if (mod != NULL) {
printf("interface %s.%d already present in the KLD"
" '%s'!\n", modname, ver,
mod->container->filename);
return (EEXIST);
}
}
for (mdp = start; mdp < stop; mdp++) {
mp = *mdp;
if (mp->md_type != MDT_DEPEND)
continue;
modname = mp->md_cval;
verinfo = mp->md_data;
nmodname = NULL;
for (nmdp = start; nmdp < stop; nmdp++) {
nmp = *nmdp;
if (nmp->md_type != MDT_VERSION)
continue;
nmodname = nmp->md_cval;
if (strcmp(modname, nmodname) == 0)
break;
}
if (nmdp < stop)/* early exit, it's a self reference */
continue;
mod = modlist_lookup2(modname, verinfo);
if (mod) { /* woohoo, it's loaded already */
lfdep = mod->container;
lfdep->refs++;
error = linker_file_add_dependency(lf, lfdep);
if (error)
break;
continue;
}
error = linker_load_module(NULL, modname, lf, verinfo, NULL);
if (error) {
printf("KLD %s: depends on %s - not available or"
" version mismatch\n", lf->filename, modname);
break;
}
}
if (error)
return (error);
linker_addmodules(lf, start, stop, 0);
return (error);
}
static int
sysctl_kern_function_list_iterate(const char *name, void *opaque)
{
struct sysctl_req *req;
req = opaque;
return (SYSCTL_OUT(req, name, strlen(name) + 1));
}
/*
* Export a nul-separated, double-nul-terminated list of all function names
* in the kernel.
*/
static int
sysctl_kern_function_list(SYSCTL_HANDLER_ARGS)
{
linker_file_t lf;
int error;
#ifdef MAC
error = mac_kld_check_stat(req->td->td_ucred);
if (error)
return (error);
#endif
error = sysctl_wire_old_buffer(req, 0);
if (error != 0)
return (error);
sx_xlock(&kld_sx);
TAILQ_FOREACH(lf, &linker_files, link) {
error = LINKER_EACH_FUNCTION_NAME(lf,
sysctl_kern_function_list_iterate, req);
if (error) {
sx_xunlock(&kld_sx);
return (error);
}
}
sx_xunlock(&kld_sx);
return (SYSCTL_OUT(req, "", 1));
}
SYSCTL_PROC(_kern, OID_AUTO, function_list,
CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
sysctl_kern_function_list, "",
"kernel function list");
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