diff options
Diffstat (limited to 'sys/kern/kern_environment.c')
| -rw-r--r-- | sys/kern/kern_environment.c | 483 |
1 files changed, 483 insertions, 0 deletions
diff --git a/sys/kern/kern_environment.c b/sys/kern/kern_environment.c new file mode 100644 index 0000000..9511c90 --- /dev/null +++ b/sys/kern/kern_environment.c @@ -0,0 +1,483 @@ +/*- + * 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 "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); +} |
