freebsd-dev/sys/kern/kern_environment.c
Kip Macy 8451d0dd78 In order to maximize the re-usability of kernel code in user space this
patch modifies makesyscalls.sh to prefix all of the non-compatibility
calls (e.g. not linux_, freebsd32_) with sys_ and updates the kernel
entry points and all places in the code that use them. It also
fixes an additional name space collision between the kernel function
psignal and the libc function of the same name by renaming the kernel
psignal kern_psignal(). By introducing this change now we will ease future
MFCs that change syscalls.

Reviewed by:	rwatson
Approved by:	re (bz)
2011-09-16 13:58:51 +00:00

624 lines
12 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.
*/
/*
* 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 <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, 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_kenv_check_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_kenv_check_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_kenv_check_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);
}
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;
size_t len;
int i;
kenvp = malloc((KENV_SIZE + 1) * sizeof(char *), M_KENV,
M_WAITOK | M_ZERO);
i = 0;
for (cp = kern_envp; cp != NULL; cp = 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);
} 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)
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 *
getenv(const char *name)
{
char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1];
char *ret, *cp;
int len;
if (dynamic_kenv) {
mtx_lock(&kenv_lock);
cp = _getenv_dynamic(name, NULL);
if (cp != NULL) {
strcpy(buf, cp);
mtx_unlock(&kenv_lock);
len = strlen(buf) + 1;
ret = malloc(len, M_KENV, M_WAITOK);
strcpy(ret, buf);
} else {
mtx_unlock(&kenv_lock);
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
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)
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);
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
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);
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 *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 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;
char *vtp;
quad_t iv;
value = getenv(name);
if (value == NULL)
return (0);
iv = strtoq(value, &vtp, 0);
if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0')) {
freeenv(value);
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:
freeenv(value);
return (0);
}
*data = iv;
freeenv(value);
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);
}