freebsd-dev/sys/kern/kern_environment.c
2003-02-19 05:47:46 +00:00

483 lines
9.6 KiB
C

/*-
* 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.
*
* $FreeBSD$
*/
/*
* 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 getenv()/freeenv() setenv() unsetenv() testenv() for
* the kernel.
*/
#include "opt_mac.h"
#include <sys/types.h>
#include <sys/param.h>
#include <sys/proc.h>
#include <sys/queue.h>
#include <sys/lock.h>
#include <sys/mac.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/kernel.h>
#include <sys/sx.h>
#include <sys/systm.h>
#include <sys/sysent.h>
#include <sys/sysproto.h>
#include <sys/libkern.h>
#include <sys/kenv.h>
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 char *kernenv_next(char *);
/* dynamic environment variables */
char **kenvp;
struct sx 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
kenv(td, uap)
struct thread *td;
struct kenv_args /* {
int what;
const char *name;
char *value;
int len;
} */ *uap;
{
char *name, *value;
size_t len, done;
int error, i;
KASSERT(dynamic_kenv, ("kenv: dynamic_kenv = 0"));
error = 0;
if (uap->what == KENV_DUMP) {
#ifdef MAC
error = mac_check_kenv_dump(td->td_ucred);
if (error)
return (error);
#endif
len = 0;
/* Return the size if called with a NULL buffer */
if (uap->value == NULL) {
sx_slock(&kenv_lock);
for (i = 0; kenvp[i] != NULL; i++)
len += strlen(kenvp[i]) + 1;
sx_sunlock(&kenv_lock);
td->td_retval[0] = len;
return (0);
}
done = 0;
sx_slock(&kenv_lock);
for (i = 0; kenvp[i] != NULL && done < uap->len; i++) {
len = min(strlen(kenvp[i]) + 1, uap->len - done);
error = copyout(kenvp[i], uap->value + done,
len);
if (error) {
sx_sunlock(&kenv_lock);
return (error);
}
done += len;
}
sx_sunlock(&kenv_lock);
return (0);
}
if ((uap->what == KENV_SET) ||
(uap->what == KENV_UNSET)) {
error = suser(td);
if (error)
return (error);
}
name = malloc(KENV_MNAMELEN, M_TEMP, M_WAITOK);
error = copyinstr(uap->name, name, KENV_MNAMELEN, NULL);
if (error)
goto done;
switch (uap->what) {
case KENV_GET:
#ifdef MAC
error = mac_check_kenv_get(td->td_ucred, name);
if (error)
goto done;
#endif
value = 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)
len = KENV_MVALLEN;
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_check_kenv_set(td->td_ucred, name, value);
if (error == 0)
#endif
setenv(name, value);
free(value, M_TEMP);
break;
case KENV_UNSET:
#ifdef MAC
error = mac_check_kenv_unset(td->td_ucred, name);
if (error)
goto done;
#endif
error = unsetenv(name);
if (error)
error = ENOENT;
break;
default:
error = EINVAL;
break;
}
done:
free(name, M_TEMP);
return (error);
}
/*
* Setup the dynamic kernel environment.
*/
static void
init_dynamic_kenv(void *data __unused)
{
char *cp;
int len, i;
kenvp = malloc(KENV_SIZE * sizeof(char *), M_KENV, M_WAITOK | M_ZERO);
i = 0;
for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) {
len = strlen(cp) + 1;
kenvp[i] = malloc(len, M_KENV, M_WAITOK);
strcpy(kenvp[i++], cp);
}
kenvp[i] = NULL;
sx_init(&kenv_lock, "kernel environment");
dynamic_kenv = 1;
}
SYSINIT(kenv, SI_SUB_KMEM, SI_ORDER_ANY, init_dynamic_kenv, NULL);
void
freeenv(char *env)
{
if (dynamic_kenv)
free(env, M_KENV);
}
/*
* Internal functions for string lookup.
*/
static char *
_getenv_dynamic(const char *name, int *idx)
{
char *cp;
int len, i;
sx_assert(&kenv_lock, SX_LOCKED);
len = strlen(name);
for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) {
if ((cp[len] == '=') &&
(strncmp(cp, name, len) == 0)) {
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 *
getenv(const char *name)
{
char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1];
char *ret, *cp;
int len;
if (dynamic_kenv) {
sx_slock(&kenv_lock);
cp = _getenv_dynamic(name, NULL);
if (cp != NULL) {
strcpy(buf, cp);
sx_sunlock(&kenv_lock);
len = strlen(buf) + 1;
ret = malloc(len, M_KENV, M_WAITOK);
strcpy(ret, buf);
} else {
sx_sunlock(&kenv_lock);
ret = NULL;
}
} else
ret = _getenv_static(name);
return (ret);
}
/*
* Test if an environment variable is defined.
*/
int
testenv(const char *name)
{
char *cp;
if (dynamic_kenv) {
sx_slock(&kenv_lock);
cp = _getenv_dynamic(name, NULL);
sx_sunlock(&kenv_lock);
} else
cp = _getenv_static(name);
if (cp != NULL)
return (1);
return (0);
}
/*
* Set an environment variable by name.
*/
int
setenv(const char *name, const char *value)
{
char *buf, *cp, *oldenv;
int namelen, vallen, i;
KENV_CHECK;
namelen = strlen(name) + 1;
if (namelen > KENV_MNAMELEN)
return (-1);
vallen = strlen(value) + 1;
if (vallen > KENV_MVALLEN)
return (-1);
buf = malloc(namelen + vallen, M_KENV, M_WAITOK);
sprintf(buf, "%s=%s", name, value);
sx_xlock(&kenv_lock);
cp = _getenv_dynamic(name, &i);
if (cp != NULL) {
oldenv = kenvp[i];
kenvp[i] = buf;
sx_xunlock(&kenv_lock);
free(oldenv, M_KENV);
} else {
/* We add the option if it wasn't found */
for (i = 0; (cp = kenvp[i]) != NULL; i++)
;
kenvp[i] = buf;
kenvp[i + 1] = NULL;
sx_xunlock(&kenv_lock);
}
return (0);
}
/*
* Unset an environment variable string.
*/
int
unsetenv(const char *name)
{
char *cp, *oldenv;
int i, j;
KENV_CHECK;
sx_xlock(&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;
sx_xunlock(&kenv_lock);
free(oldenv, M_KENV);
return (0);
}
sx_xunlock(&kenv_lock);
return (-1);
}
/*
* Return a string value from an environment variable.
*/
int
getenv_string(const char *name, char *data, int size)
{
char *tmp;
tmp = getenv(name);
if (tmp != NULL) {
strlcpy(data, tmp, size);
freeenv(tmp);
return (1);
} else
return (0);
}
/*
* 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 a quad_t value from an environment variable.
*/
int
getenv_quad(const char *name, quad_t *data)
{
char *value;
char *vtp;
quad_t iv;
value = getenv(name);
if (value == NULL)
return (0);
iv = strtoq(value, &vtp, 0);
if ((vtp == value) || (*vtp != '\0')) {
freeenv(value);
return (0);
}
freeenv(value);
*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_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);
}