2 * Copyright (c) 1998 Michael Smith
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * The unified bootloader passes us a pointer to a preserved copy of
29 * bootstrap/kernel environment variables. We convert them to a
30 * dynamic array of strings later when the VM subsystem is up.
32 * We make these available through the kenv(2) syscall for userland
33 * and through getenv()/freeenv() setenv() unsetenv() testenv() for
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
40 #include <sys/types.h>
41 #include <sys/param.h>
43 #include <sys/queue.h>
45 #include <sys/malloc.h>
46 #include <sys/mutex.h>
48 #include <sys/kernel.h>
49 #include <sys/systm.h>
50 #include <sys/sysent.h>
51 #include <sys/sysproto.h>
52 #include <sys/libkern.h>
55 #include <security/mac/mac_framework.h>
57 static MALLOC_DEFINE(M_KENV, "kenv", "kernel environment");
59 #define KENV_SIZE 512 /* Maximum number of environment strings */
61 /* pointer to the static environment */
65 static char *kernenv_next(char *);
67 /* dynamic environment variables */
72 * No need to protect this with a mutex since SYSINITS are single threaded.
76 #define KENV_CHECK if (!dynamic_kenv) \
77 panic("%s: called before SI_SUB_KMEM", __func__)
89 char *name, *value, *buffer = NULL;
90 size_t len, done, needed, buflen;
93 KASSERT(dynamic_kenv, ("kenv: dynamic_kenv = 0"));
96 if (uap->what == KENV_DUMP) {
98 error = mac_kenv_check_dump(td->td_ucred);
104 if (buflen > KENV_SIZE * (KENV_MNAMELEN + KENV_MVALLEN + 2))
105 buflen = KENV_SIZE * (KENV_MNAMELEN +
107 if (uap->len > 0 && uap->value != NULL)
108 buffer = malloc(buflen, M_TEMP, M_WAITOK|M_ZERO);
109 mtx_lock(&kenv_lock);
110 for (i = 0; kenvp[i] != NULL; i++) {
111 len = strlen(kenvp[i]) + 1;
113 len = min(len, buflen - done);
115 * If called with a NULL or insufficiently large
116 * buffer, just keep computing the required size.
118 if (uap->value != NULL && buffer != NULL && len > 0) {
119 bcopy(kenvp[i], buffer + done, len);
123 mtx_unlock(&kenv_lock);
124 if (buffer != NULL) {
125 error = copyout(buffer, uap->value, done);
126 free(buffer, M_TEMP);
128 td->td_retval[0] = ((done == needed) ? 0 : needed);
134 error = priv_check(td, PRIV_KENV_SET);
140 error = priv_check(td, PRIV_KENV_UNSET);
146 name = malloc(KENV_MNAMELEN + 1, M_TEMP, M_WAITOK);
148 error = copyinstr(uap->name, name, KENV_MNAMELEN + 1, NULL);
155 error = mac_kenv_check_get(td->td_ucred, name);
159 value = getenv(name);
164 len = strlen(value) + 1;
167 error = copyout(value, uap->value, len);
171 td->td_retval[0] = len;
179 if (len > KENV_MVALLEN + 1)
180 len = KENV_MVALLEN + 1;
181 value = malloc(len, M_TEMP, M_WAITOK);
182 error = copyinstr(uap->value, value, len, NULL);
188 error = mac_kenv_check_set(td->td_ucred, name, value);
196 error = mac_kenv_check_unset(td->td_ucred, name);
200 error = unsetenv(name);
214 * Populate the initial kernel environment.
216 * This is called very early in MD startup, either to provide a copy of the
217 * environment obtained from a boot loader, or to provide an empty buffer into
218 * which MD code can store an initial environment using kern_setenv() calls.
220 * If the global envmode is 1, the environment is initialized from the global
221 * static_env[], regardless of the arguments passed. This implements the env
222 * keyword described in config(5). In this case env_pos is set to env_len,
223 * causing kern_setenv() to return -1 (if len > 0) or panic (if len == 0) until
224 * the dynamic environment is available. The envmode and static_env variables
225 * are defined in env.c which is generated by config(8).
227 * If len is non-zero, the caller is providing an empty buffer. The caller will
228 * subsequently use kern_setenv() to add up to len bytes of initial environment
229 * before the dynamic environment is available.
231 * If len is zero, the caller is providing a pre-loaded buffer containing
232 * environment strings. Additional strings cannot be added until the dynamic
233 * environment is available. The memory pointed to must remain stable at least
234 * until sysinit runs init_dynamic_kenv(). If no initial environment is
235 * available from the boot loader, passing a NULL pointer allows the static_env
236 * to be installed if it is configured.
239 init_static_kenv(char *buf, size_t len)
243 kern_envp = static_env;
254 * Setup the dynamic kernel environment.
257 init_dynamic_kenv(void *data __unused)
263 kenvp = malloc((KENV_SIZE + 1) * sizeof(char *), M_KENV,
266 if (kern_envp && *kern_envp != '\0') {
267 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) {
268 len = strlen(cp) + 1;
269 if (len > KENV_MNAMELEN + 1 + KENV_MVALLEN + 1) {
271 "WARNING: too long kenv string, ignoring %s\n",
276 kenvp[i] = malloc(len, M_KENV, M_WAITOK);
277 strcpy(kenvp[i++], cp);
280 "WARNING: too many kenv strings, ignoring %s\n",
286 mtx_init(&kenv_lock, "kernel environment", NULL, MTX_DEF);
289 SYSINIT(kenv, SI_SUB_KMEM, SI_ORDER_ANY, init_dynamic_kenv, NULL);
300 * Internal functions for string lookup.
303 _getenv_dynamic(const char *name, int *idx)
308 mtx_assert(&kenv_lock, MA_OWNED);
310 for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) {
311 if ((strncmp(cp, name, len) == 0) &&
315 return (cp + len + 1);
322 _getenv_static(const char *name)
327 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) {
328 for (ep = cp; (*ep != '=') && (*ep != 0); ep++)
334 if (!strncmp(name, cp, len) && name[len] == 0)
341 * Look up an environment variable by name.
342 * Return a pointer to the string if found.
343 * The pointer has to be freed with freeenv()
347 getenv(const char *name)
349 char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1];
353 if (getenv_string(name, buf, sizeof(buf))) {
354 ret = strdup(buf, M_KENV);
357 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
361 ret = _getenv_static(name);
366 * Test if an environment variable is defined.
369 testenv(const char *name)
374 mtx_lock(&kenv_lock);
375 cp = _getenv_dynamic(name, NULL);
376 mtx_unlock(&kenv_lock);
378 cp = _getenv_static(name);
385 setenv_static(const char *name, const char *value)
389 if (env_pos >= env_len)
392 /* Check space for x=y and two nuls */
393 len = strlen(name) + strlen(value);
394 if (len + 3 < env_len - env_pos) {
395 len = sprintf(&kern_envp[env_pos], "%s=%s", name, value);
397 kern_envp[env_pos] = '\0';
405 * Set an environment variable by name.
408 setenv(const char *name, const char *value)
410 char *buf, *cp, *oldenv;
411 int namelen, vallen, i;
413 if (dynamic_kenv == 0 && env_len > 0)
414 return (setenv_static(name, value));
418 namelen = strlen(name) + 1;
419 if (namelen > KENV_MNAMELEN + 1)
421 vallen = strlen(value) + 1;
422 if (vallen > KENV_MVALLEN + 1)
424 buf = malloc(namelen + vallen, M_KENV, M_WAITOK);
425 sprintf(buf, "%s=%s", name, value);
427 mtx_lock(&kenv_lock);
428 cp = _getenv_dynamic(name, &i);
432 mtx_unlock(&kenv_lock);
433 free(oldenv, M_KENV);
435 /* We add the option if it wasn't found */
436 for (i = 0; (cp = kenvp[i]) != NULL; i++)
439 /* Bounds checking */
440 if (i < 0 || i >= KENV_SIZE) {
442 mtx_unlock(&kenv_lock);
448 mtx_unlock(&kenv_lock);
454 * Unset an environment variable string.
457 unsetenv(const char *name)
464 mtx_lock(&kenv_lock);
465 cp = _getenv_dynamic(name, &i);
468 for (j = i + 1; kenvp[j] != NULL; j++)
469 kenvp[i++] = kenvp[j];
471 mtx_unlock(&kenv_lock);
472 free(oldenv, M_KENV);
475 mtx_unlock(&kenv_lock);
480 * Return a string value from an environment variable.
483 getenv_string(const char *name, char *data, int size)
488 mtx_lock(&kenv_lock);
489 cp = _getenv_dynamic(name, NULL);
491 strlcpy(data, cp, size);
492 mtx_unlock(&kenv_lock);
494 cp = _getenv_static(name);
496 strlcpy(data, cp, size);
502 * Return an integer value from an environment variable.
505 getenv_int(const char *name, int *data)
510 rval = getenv_quad(name, &tmp);
517 * Return an unsigned integer value from an environment variable.
520 getenv_uint(const char *name, unsigned int *data)
525 rval = getenv_quad(name, &tmp);
527 *data = (unsigned int) tmp;
532 * Return a long value from an environment variable.
535 getenv_long(const char *name, long *data)
540 rval = getenv_quad(name, &tmp);
547 * Return an unsigned long value from an environment variable.
550 getenv_ulong(const char *name, unsigned long *data)
555 rval = getenv_quad(name, &tmp);
557 *data = (unsigned long) tmp;
562 * Return a quad_t value from an environment variable.
565 getenv_quad(const char *name, quad_t *data)
567 char value[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1];
571 if (!getenv_string(name, value, sizeof(value)))
573 iv = strtoq(value, &vtp, 0);
574 if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0'))
595 * Find the next entry after the one which (cp) falls within, return a
596 * pointer to its start or NULL if there are no more.
599 kernenv_next(char *cp)
613 tunable_int_init(void *data)
615 struct tunable_int *d = (struct tunable_int *)data;
617 TUNABLE_INT_FETCH(d->path, d->var);
621 tunable_long_init(void *data)
623 struct tunable_long *d = (struct tunable_long *)data;
625 TUNABLE_LONG_FETCH(d->path, d->var);
629 tunable_ulong_init(void *data)
631 struct tunable_ulong *d = (struct tunable_ulong *)data;
633 TUNABLE_ULONG_FETCH(d->path, d->var);
637 tunable_quad_init(void *data)
639 struct tunable_quad *d = (struct tunable_quad *)data;
641 TUNABLE_QUAD_FETCH(d->path, d->var);
645 tunable_str_init(void *data)
647 struct tunable_str *d = (struct tunable_str *)data;
649 TUNABLE_STR_FETCH(d->path, d->var, d->size);