/*-
* Copyright (c) 1998 Michael Smith
* 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.
*/
/*
* The unified bootloader passes us a pointer to a preserved copy of
* bootstrap/kernel environment variables. We convert them to a
* dynamic array of strings later when the VM subsystem is up.
*
* We make these available through the kenv(2) syscall for userland
* and through kern_getenv()/freeenv() kern_setenv() kern_unsetenv() testenv() for
* the kernel.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <sys/param.h>
#include <sys/proc.h>
#include <sys/queue.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/priv.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/sysent.h>
#include <sys/sysproto.h>
#include <sys/libkern.h>
#include <sys/kenv.h>
#include <security/mac/mac_framework.h>
static MALLOC_DEFINE(M_KENV, "kenv", "kernel environment");
#define KENV_SIZE 512 /* Maximum number of environment strings */
/* pointer to the static environment */
char *kern_envp;
static int env_len;
static int env_pos;
static char *kernenv_next(char *);
/* dynamic environment variables */
char **kenvp;
struct mtx kenv_lock;
/*
* No need to protect this with a mutex since SYSINITS are single threaded.
*/
int dynamic_kenv = 0;
#define KENV_CHECK if (!dynamic_kenv) \
panic("%s: called before SI_SUB_KMEM", __func__)
int
sys_kenv(td, uap)
struct thread *td;
struct kenv_args /* {
int what;
const char *name;
char *value;
int len;
} */ *uap;
{
char *name, *value, *buffer = NULL;
size_t len, done, needed, buflen;
int error, i;
KASSERT(dynamic_kenv, ("kenv: dynamic_kenv = 0"));
error = 0;
if (uap->what == KENV_DUMP) {
#ifdef MAC
error = mac_kenv_check_dump(td->td_ucred);
if (error)
return (error);
#endif
done = needed = 0;
buflen = uap->len;
if (buflen > KENV_SIZE * (KENV_MNAMELEN + KENV_MVALLEN + 2))
buflen = KENV_SIZE * (KENV_MNAMELEN +
KENV_MVALLEN + 2);
if (uap->len > 0 && uap->value != NULL)
buffer = malloc(buflen, M_TEMP, M_WAITOK|M_ZERO);
mtx_lock(&kenv_lock);
for (i = 0; kenvp[i] != NULL; i++) {
len = strlen(kenvp[i]) + 1;
needed += len;
len = min(len, buflen - done);
/*
* If called with a NULL or insufficiently large
* buffer, just keep computing the required size.
*/
if (uap->value != NULL && buffer != NULL && len > 0) {
bcopy(kenvp[i], buffer + done, len);
done += len;
}
}
mtx_unlock(&kenv_lock);
if (buffer != NULL) {
error = copyout(buffer, uap->value, done);
free(buffer, M_TEMP);
}
td->td_retval[0] = ((done == needed) ? 0 : needed);
return (error);
}
switch (uap->what) {
case KENV_SET:
error = priv_check(td, PRIV_KENV_SET);
if (error)
return (error);
break;
case KENV_UNSET:
error = priv_check(td, PRIV_KENV_UNSET);
if (error)
return (error);
break;
}
name = malloc(KENV_MNAMELEN + 1, M_TEMP, M_WAITOK);
error = copyinstr(uap->name, name, KENV_MNAMELEN + 1, NULL);
if (error)
goto done;
switch (uap->what) {
case KENV_GET:
#ifdef MAC
error = mac_kenv_check_get(td->td_ucred, name);
if (error)
goto done;
#endif
value = kern_getenv(name);
if (value == NULL) {
error = ENOENT;
goto done;
}
len = strlen(value) + 1;
if (len > uap->len)
len = uap->len;
error = copyout(value, uap->value, len);
freeenv(value);
if (error)
goto done;
td->td_retval[0] = len;
break;
case KENV_SET:
len = uap->len;
if (len < 1) {
error = EINVAL;
goto done;
}
if (len > KENV_MVALLEN + 1)
len = KENV_MVALLEN + 1;
value = malloc(len, M_TEMP, M_WAITOK);
error = copyinstr(uap->value, value, len, NULL);
if (error) {
free(value, M_TEMP);
goto done;
}
#ifdef MAC
error = mac_kenv_check_set(td->td_ucred, name, value);
if (error == 0)
#endif
kern_setenv(name, value);
free(value, M_TEMP);
break;
case KENV_UNSET:
#ifdef MAC
error = mac_kenv_check_unset(td->td_ucred, name);
if (error)
goto done;
#endif
error = kern_unsetenv(name);
if (error)
error = ENOENT;
break;
default:
error = EINVAL;
break;
}
done:
free(name, M_TEMP);
return (error);
}
void
init_static_kenv(char *buf, size_t len)
{
kern_envp = buf;
env_len = len;
env_pos = 0;
}
/*
* Setup the dynamic kernel environment.
*/
static void
init_dynamic_kenv(void *data __unused)
{
char *cp, *cpnext;
size_t len;
int i;
kenvp = malloc((KENV_SIZE + 1) * sizeof(char *), M_KENV,
M_WAITOK | M_ZERO);
i = 0;
if (kern_envp && *kern_envp != '\0') {
for (cp = kern_envp; cp != NULL; cp = cpnext) {
cpnext = kernenv_next(cp);
len = strlen(cp) + 1;
if (len > KENV_MNAMELEN + 1 + KENV_MVALLEN + 1) {
printf(
"WARNING: too long kenv string, ignoring %s\n",
cp);
continue;
}
if (i < KENV_SIZE) {
kenvp[i] = malloc(len, M_KENV, M_WAITOK);
strcpy(kenvp[i++], cp);
memset(cp, 0, strlen(cp));
} else
printf(
"WARNING: too many kenv strings, ignoring %s\n",
cp);
}
}
kenvp[i] = NULL;
mtx_init(&kenv_lock, "kernel environment", NULL, MTX_DEF);
dynamic_kenv = 1;
}
SYSINIT(kenv, SI_SUB_KMEM, SI_ORDER_ANY, init_dynamic_kenv, NULL);
void
freeenv(char *env)
{
if (dynamic_kenv && env != NULL) {
memset(env, 0, strlen(env));
free(env, M_KENV);
}
}
/*
* Internal functions for string lookup.
*/
static char *
_getenv_dynamic(const char *name, int *idx)
{
char *cp;
int len, i;
mtx_assert(&kenv_lock, MA_OWNED);
len = strlen(name);
for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) {
if ((strncmp(cp, name, len) == 0) &&
(cp[len] == '=')) {
if (idx != NULL)
*idx = i;
return (cp + len + 1);
}
}
return (NULL);
}
static char *
_getenv_static(const char *name)
{
char *cp, *ep;
int len;
for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) {
for (ep = cp; (*ep != '=') && (*ep != 0); ep++)
;
if (*ep != '=')
continue;
len = ep - cp;
ep++;
if (!strncmp(name, cp, len) && name[len] == 0)
return (ep);
}
return (NULL);
}
/*
* Look up an environment variable by name.
* Return a pointer to the string if found.
* The pointer has to be freed with freeenv()
* after use.
*/
char *
kern_getenv(const char *name)
{
char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1];
char *ret;
if (dynamic_kenv) {
if (getenv_string(name, buf, sizeof(buf))) {
ret = strdup(buf, M_KENV);
} else {
ret = NULL;
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
"getenv");
}
} else
ret = _getenv_static(name);
return (ret);
}
/*
* Test if an environment variable is defined.
*/
int
testenv(const char *name)
{
char *cp;
if (dynamic_kenv) {
mtx_lock(&kenv_lock);
cp = _getenv_dynamic(name, NULL);
mtx_unlock(&kenv_lock);
} else
cp = _getenv_static(name);
if (cp != NULL)
return (1);
return (0);
}
static int
setenv_static(const char *name, const char *value)
{
int len;
if (env_pos >= env_len)
return (-1);
/* Check space for x=y and two nuls */
len = strlen(name) + strlen(value);
if (len + 3 < env_len - env_pos) {
len = sprintf(&kern_envp[env_pos], "%s=%s", name, value);
env_pos += len+1;
kern_envp[env_pos] = '\0';
return (0);
} else
return (-1);
}
/*
* Set an environment variable by name.
*/
int
kern_setenv(const char *name, const char *value)
{
char *buf, *cp, *oldenv;
int namelen, vallen, i;
if (dynamic_kenv == 0 && env_len > 0)
return (setenv_static(name, value));
KENV_CHECK;
namelen = strlen(name) + 1;
if (namelen > KENV_MNAMELEN + 1)
return (-1);
vallen = strlen(value) + 1;
if (vallen > KENV_MVALLEN + 1)
return (-1);
buf = malloc(namelen + vallen, M_KENV, M_WAITOK);
sprintf(buf, "%s=%s", name, value);
mtx_lock(&kenv_lock);
cp = _getenv_dynamic(name, &i);
if (cp != NULL) {
oldenv = kenvp[i];
kenvp[i] = buf;
mtx_unlock(&kenv_lock);
free(oldenv, M_KENV);
} else {
/* We add the option if it wasn't found */
for (i = 0; (cp = kenvp[i]) != NULL; i++)
;
/* Bounds checking */
if (i < 0 || i >= KENV_SIZE) {
free(buf, M_KENV);
mtx_unlock(&kenv_lock);
return (-1);
}
kenvp[i] = buf;
kenvp[i + 1] = NULL;
mtx_unlock(&kenv_lock);
}
return (0);
}
/*
* Unset an environment variable string.
*/
int
kern_unsetenv(const char *name)
{
char *cp, *oldenv;
int i, j;
KENV_CHECK;
mtx_lock(&kenv_lock);
cp = _getenv_dynamic(name, &i);
if (cp != NULL) {
oldenv = kenvp[i];
for (j = i + 1; kenvp[j] != NULL; j++)
kenvp[i++] = kenvp[j];
kenvp[i] = NULL;
mtx_unlock(&kenv_lock);
memset(oldenv, 0, strlen(oldenv));
free(oldenv, M_KENV);
return (0);
}
mtx_unlock(&kenv_lock);
return (-1);
}
/*
* Return a string value from an environment variable.
*/
int
getenv_string(const char *name, char *data, int size)
{
char *cp;
if (dynamic_kenv) {
mtx_lock(&kenv_lock);
cp = _getenv_dynamic(name, NULL);
if (cp != NULL)
strlcpy(data, cp, size);
mtx_unlock(&kenv_lock);
} else {
cp = _getenv_static(name);
if (cp != NULL)
strlcpy(data, cp, size);
}
return (cp != NULL);
}
/*
* Return an integer value from an environment variable.
*/
int
getenv_int(const char *name, int *data)
{
quad_t tmp;
int rval;
rval = getenv_quad(name, &tmp);
if (rval)
*data = (int) tmp;
return (rval);
}
/*
* Return an unsigned integer value from an environment variable.
*/
int
getenv_uint(const char *name, unsigned int *data)
{
quad_t tmp;
int rval;
rval = getenv_quad(name, &tmp);
if (rval)
*data = (unsigned int) tmp;
return (rval);
}
/*
* Return a long value from an environment variable.
*/
int
getenv_long(const char *name, long *data)
{
quad_t tmp;
int rval;
rval = getenv_quad(name, &tmp);
if (rval)
*data = (long) tmp;
return (rval);
}
/*
* Return an unsigned long value from an environment variable.
*/
int
getenv_ulong(const char *name, unsigned long *data)
{
quad_t tmp;
int rval;
rval = getenv_quad(name, &tmp);
if (rval)
*data = (unsigned long) tmp;
return (rval);
}
/*
* Return a quad_t value from an environment variable.
*/
int
getenv_quad(const char *name, quad_t *data)
{
char value[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1];
char *vtp;
quad_t iv;
if (!getenv_string(name, value, sizeof(value)))
return (0);
iv = strtoq(value, &vtp, 0);
if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0'))
return (0);
switch (vtp[0]) {
case 't': case 'T':
iv *= 1024;
case 'g': case 'G':
iv *= 1024;
case 'm': case 'M':
iv *= 1024;
case 'k': case 'K':
iv *= 1024;
case '\0':
break;
default:
return (0);
}
*data = iv;
return (1);
}
/*
* Find the next entry after the one which (cp) falls within, return a
* pointer to its start or NULL if there are no more.
*/
static char *
kernenv_next(char *cp)
{
if (cp != NULL) {
while (*cp != 0)
cp++;
cp++;
if (*cp == 0)
cp = NULL;
}
return (cp);
}
void
tunable_int_init(void *data)
{
struct tunable_int *d = (struct tunable_int *)data;
TUNABLE_INT_FETCH(d->path, d->var);
}
void
tunable_long_init(void *data)
{
struct tunable_long *d = (struct tunable_long *)data;
TUNABLE_LONG_FETCH(d->path, d->var);
}
void
tunable_ulong_init(void *data)
{
struct tunable_ulong *d = (struct tunable_ulong *)data;
TUNABLE_ULONG_FETCH(d->path, d->var);
}
void
tunable_quad_init(void *data)
{
struct tunable_quad *d = (struct tunable_quad *)data;
TUNABLE_QUAD_FETCH(d->path, d->var);
}
void
tunable_str_init(void *data)
{
struct tunable_str *d = (struct tunable_str *)data;
TUNABLE_STR_FETCH(d->path, d->var, d->size);
}
