2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 1998 Michael Smith
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * The unified bootloader passes us a pointer to a preserved copy of
31 * bootstrap/kernel environment variables. We convert them to a
32 * dynamic array of strings later when the VM subsystem is up.
34 * We make these available through the kenv(2) syscall for userland
35 * and through kern_getenv()/freeenv() kern_setenv() kern_unsetenv() testenv() for
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD$");
42 #include <sys/param.h>
44 #include <sys/queue.h>
46 #include <sys/malloc.h>
47 #include <sys/mutex.h>
49 #include <sys/kernel.h>
50 #include <sys/systm.h>
51 #include <sys/sysent.h>
52 #include <sys/sysproto.h>
53 #include <sys/libkern.h>
55 #include <sys/limits.h>
57 #include <security/mac/mac_framework.h>
59 static char *_getenv_dynamic_locked(const char *name, int *idx);
60 static char *_getenv_dynamic(const char *name, int *idx);
62 static MALLOC_DEFINE(M_KENV, "kenv", "kernel environment");
64 #define KENV_SIZE 512 /* Maximum number of environment strings */
66 /* pointer to the config-generated static environment */
69 /* pointer to the md-static environment */
71 static int md_env_len;
72 static int md_env_pos;
74 static char *kernenv_next(char *);
76 /* dynamic environment variables */
81 * No need to protect this with a mutex since SYSINITS are single threaded.
85 #define KENV_CHECK if (!dynamic_kenv) \
86 panic("%s: called before SI_SUB_KMEM", __func__)
98 char *name, *value, *buffer = NULL;
99 size_t len, done, needed, buflen;
102 KASSERT(dynamic_kenv, ("kenv: dynamic_kenv = false"));
105 if (uap->what == KENV_DUMP) {
107 error = mac_kenv_check_dump(td->td_ucred);
113 if (buflen > KENV_SIZE * (KENV_MNAMELEN + KENV_MVALLEN + 2))
114 buflen = KENV_SIZE * (KENV_MNAMELEN +
116 if (uap->len > 0 && uap->value != NULL)
117 buffer = malloc(buflen, M_TEMP, M_WAITOK|M_ZERO);
118 mtx_lock(&kenv_lock);
119 for (i = 0; kenvp[i] != NULL; i++) {
120 len = strlen(kenvp[i]) + 1;
122 len = min(len, buflen - done);
124 * If called with a NULL or insufficiently large
125 * buffer, just keep computing the required size.
127 if (uap->value != NULL && buffer != NULL && len > 0) {
128 bcopy(kenvp[i], buffer + done, len);
132 mtx_unlock(&kenv_lock);
133 if (buffer != NULL) {
134 error = copyout(buffer, uap->value, done);
135 free(buffer, M_TEMP);
137 td->td_retval[0] = ((done == needed) ? 0 : needed);
143 error = priv_check(td, PRIV_KENV_SET);
149 error = priv_check(td, PRIV_KENV_UNSET);
155 name = malloc(KENV_MNAMELEN + 1, M_TEMP, M_WAITOK);
157 error = copyinstr(uap->name, name, KENV_MNAMELEN + 1, NULL);
164 error = mac_kenv_check_get(td->td_ucred, name);
168 value = kern_getenv(name);
173 len = strlen(value) + 1;
176 error = copyout(value, uap->value, len);
180 td->td_retval[0] = len;
188 if (len > KENV_MVALLEN + 1)
189 len = KENV_MVALLEN + 1;
190 value = malloc(len, M_TEMP, M_WAITOK);
191 error = copyinstr(uap->value, value, len, NULL);
197 error = mac_kenv_check_set(td->td_ucred, name, value);
200 kern_setenv(name, value);
205 error = mac_kenv_check_unset(td->td_ucred, name);
209 error = kern_unsetenv(name);
223 * Populate the initial kernel environment.
225 * This is called very early in MD startup, either to provide a copy of the
226 * environment obtained from a boot loader, or to provide an empty buffer into
227 * which MD code can store an initial environment using kern_setenv() calls.
229 * kern_envp is set to the static_env generated by config(8). This implements
230 * the env keyword described in config(5).
232 * If len is non-zero, the caller is providing an empty buffer. The caller will
233 * subsequently use kern_setenv() to add up to len bytes of initial environment
234 * before the dynamic environment is available.
236 * If len is zero, the caller is providing a pre-loaded buffer containing
237 * environment strings. Additional strings cannot be added until the dynamic
238 * environment is available. The memory pointed to must remain stable at least
239 * until sysinit runs init_dynamic_kenv() and preferably until after SI_SUB_KMEM
240 * is finished so that subr_hints routines may continue to use it until the
241 * environments have been fully merged at the end of the pass. If no initial
242 * environment is available from the boot loader, passing a NULL pointer allows
243 * the static_env to be installed if it is configured. In this case, any call
244 * to kern_setenv() prior to the setup of the dynamic environment will result in
248 init_static_kenv(char *buf, size_t len)
252 KASSERT(!dynamic_kenv, ("kenv: dynamic_kenv already initialized"));
254 * Suitably sized means it must be able to hold at least one empty
255 * variable, otherwise things go belly up if a kern_getenv call is
256 * made without a prior call to kern_setenv as we have a malformed
259 KASSERT(len == 0 || len >= 2,
260 ("kenv: static env must be initialized or suitably sized"));
261 KASSERT(len == 0 || (*buf == '\0' && *(buf + 1) == '\0'),
262 ("kenv: sized buffer must be initially empty"));
265 * We may be called twice, with the second call needed to relocate
266 * md_envp after enabling paging. md_envp is then garbage if it is
267 * not null and the relocation will move it. Discard it so as to
268 * not crash using its old value in our first call to kern_getenv().
270 * The second call gives the same environment as the first except
271 * in silly configurations where the static env disables itself.
273 * Other env calls don't handle possibly-garbage pointers, so must
274 * not be made between enabling paging and calling here.
281 * Give the static environment a chance to disable the loader(8)
282 * environment first. This is done with loader_env.disabled=1.
284 * static_env and static_hints may both be disabled, but in slightly
285 * different ways. For static_env, we just don't setup kern_envp and
286 * it's as if a static env wasn't even provided. For static_hints,
287 * we effectively zero out the buffer to stop the rest of the kernel
288 * from being able to use it.
290 * We're intentionally setting this up so that static_hints.disabled may
291 * be specified in either the MD env or the static env. This keeps us
292 * consistent in our new world view.
294 * As a warning, the static environment may not be disabled in any way
295 * if the static environment has disabled the loader environment.
297 kern_envp = static_env;
298 eval = kern_getenv("loader_env.disabled");
299 if (eval == NULL || strcmp(eval, "1") != 0) {
304 eval = kern_getenv("static_env.disabled");
305 if (eval != NULL && strcmp(eval, "1") == 0) {
310 eval = kern_getenv("static_hints.disabled");
311 if (eval != NULL && strcmp(eval, "1") == 0) {
312 static_hints[0] = '\0';
313 static_hints[1] = '\0';
318 init_dynamic_kenv_from(char *init_env, int *curpos)
320 char *cp, *cpnext, *eqpos, *found;
324 if (init_env && *init_env != '\0') {
327 for (cp = init_env; cp != NULL; cp = cpnext) {
328 cpnext = kernenv_next(cp);
329 len = strlen(cp) + 1;
330 if (len > KENV_MNAMELEN + 1 + KENV_MVALLEN + 1) {
332 "WARNING: too long kenv string, ignoring %s\n",
336 eqpos = strchr(cp, '=');
339 "WARNING: malformed static env value, ignoring %s\n",
345 * De-dupe the environment as we go. We don't add the
346 * duplicated assignments because config(8) will flip
347 * the order of the static environment around to make
348 * kernel processing match the order of specification
349 * in the kernel config.
351 found = _getenv_dynamic_locked(cp, NULL);
357 "WARNING: too many kenv strings, ignoring %s\n",
362 kenvp[i] = malloc(len, M_KENV, M_WAITOK);
363 strcpy(kenvp[i++], cp);
365 explicit_bzero(cp, len - 1);
372 * Setup the dynamic kernel environment.
375 init_dynamic_kenv(void *data __unused)
379 kenvp = malloc((KENV_SIZE + 1) * sizeof(char *), M_KENV,
383 init_dynamic_kenv_from(md_envp, &dynamic_envpos);
384 init_dynamic_kenv_from(kern_envp, &dynamic_envpos);
385 kenvp[dynamic_envpos] = NULL;
387 mtx_init(&kenv_lock, "kernel environment", NULL, MTX_DEF);
390 SYSINIT(kenv, SI_SUB_KMEM + 1, SI_ORDER_FIRST, init_dynamic_kenv, NULL);
396 if (dynamic_kenv && env != NULL) {
397 explicit_bzero(env, strlen(env));
403 * Internal functions for string lookup.
406 _getenv_dynamic_locked(const char *name, int *idx)
412 for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) {
413 if ((strncmp(cp, name, len) == 0) &&
417 return (cp + len + 1);
424 _getenv_dynamic(const char *name, int *idx)
427 mtx_assert(&kenv_lock, MA_OWNED);
428 return (_getenv_dynamic_locked(name, idx));
432 _getenv_static_from(char *chkenv, const char *name)
437 for (cp = chkenv; cp != NULL; cp = kernenv_next(cp)) {
438 for (ep = cp; (*ep != '=') && (*ep != 0); ep++)
444 if (!strncmp(name, cp, len) && name[len] == 0)
451 _getenv_static(const char *name)
455 val = _getenv_static_from(md_envp, name);
458 val = _getenv_static_from(kern_envp, name);
465 * Look up an environment variable by name.
466 * Return a pointer to the string if found.
467 * The pointer has to be freed with freeenv()
471 kern_getenv(const char *name)
473 char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1];
477 if (getenv_string(name, buf, sizeof(buf))) {
478 ret = strdup(buf, M_KENV);
481 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
485 ret = _getenv_static(name);
490 * Test if an environment variable is defined.
493 testenv(const char *name)
498 mtx_lock(&kenv_lock);
499 cp = _getenv_dynamic(name, NULL);
500 mtx_unlock(&kenv_lock);
502 cp = _getenv_static(name);
509 * Set an environment variable in the MD-static environment. This cannot
510 * feasibly be done on config(8)-generated static environments as they don't
511 * generally include space for extra variables.
514 setenv_static(const char *name, const char *value)
518 if (md_env_pos >= md_env_len)
521 /* Check space for x=y and two nuls */
522 len = strlen(name) + strlen(value);
523 if (len + 3 < md_env_len - md_env_pos) {
524 len = sprintf(&md_envp[md_env_pos], "%s=%s", name, value);
526 md_envp[md_env_pos] = '\0';
534 * Set an environment variable by name.
537 kern_setenv(const char *name, const char *value)
539 char *buf, *cp, *oldenv;
540 int namelen, vallen, i;
542 if (!dynamic_kenv && md_env_len > 0)
543 return (setenv_static(name, value));
547 namelen = strlen(name) + 1;
548 if (namelen > KENV_MNAMELEN + 1)
550 vallen = strlen(value) + 1;
551 if (vallen > KENV_MVALLEN + 1)
553 buf = malloc(namelen + vallen, M_KENV, M_WAITOK);
554 sprintf(buf, "%s=%s", name, value);
556 mtx_lock(&kenv_lock);
557 cp = _getenv_dynamic(name, &i);
561 mtx_unlock(&kenv_lock);
562 free(oldenv, M_KENV);
564 /* We add the option if it wasn't found */
565 for (i = 0; (cp = kenvp[i]) != NULL; i++)
568 /* Bounds checking */
569 if (i < 0 || i >= KENV_SIZE) {
571 mtx_unlock(&kenv_lock);
577 mtx_unlock(&kenv_lock);
583 * Unset an environment variable string.
586 kern_unsetenv(const char *name)
593 mtx_lock(&kenv_lock);
594 cp = _getenv_dynamic(name, &i);
597 for (j = i + 1; kenvp[j] != NULL; j++)
598 kenvp[i++] = kenvp[j];
600 mtx_unlock(&kenv_lock);
601 explicit_bzero(oldenv, strlen(oldenv));
602 free(oldenv, M_KENV);
605 mtx_unlock(&kenv_lock);
610 * Return a string value from an environment variable.
613 getenv_string(const char *name, char *data, int size)
618 mtx_lock(&kenv_lock);
619 cp = _getenv_dynamic(name, NULL);
621 strlcpy(data, cp, size);
622 mtx_unlock(&kenv_lock);
624 cp = _getenv_static(name);
626 strlcpy(data, cp, size);
632 * Return an array of integers at the given type size and signedness.
635 getenv_array(const char *name, void *pdata, int size, int *psize,
636 int type_size, bool allow_signed)
638 char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1];
646 if (getenv_string(name, buf, sizeof(buf)) == 0)
649 /* get maximum number of elements */
654 for (ptr = buf; *ptr != 0; ) {
656 value = strtoq(ptr, &end, 0);
658 /* check if signed numbers are allowed */
659 if (value < 0 && !allow_signed)
662 /* check for invalid value */
666 /* check for valid suffix */
695 /* garbage after numeric value */
699 /* skip till next value, if any */
700 while (*end == '\t' || *end == ',' || *end == ' ')
711 if ((value >> shift) != old)
714 /* check for buffer overflow */
718 /* store value according to type size */
722 if (value < SCHAR_MIN || value > SCHAR_MAX)
725 if (value < 0 || value > UCHAR_MAX)
728 ((uint8_t *)pdata)[n] = (uint8_t)value;
732 if (value < SHRT_MIN || value > SHRT_MAX)
735 if (value < 0 || value > USHRT_MAX)
738 ((uint16_t *)pdata)[n] = (uint16_t)value;
742 if (value < INT_MIN || value > INT_MAX)
745 if (value > UINT_MAX)
748 ((uint32_t *)pdata)[n] = (uint32_t)value;
751 ((uint64_t *)pdata)[n] = (uint64_t)value;
758 *psize = n * type_size;
761 return (1); /* success */
763 return (0); /* failure */
767 * Return an integer value from an environment variable.
770 getenv_int(const char *name, int *data)
775 rval = getenv_quad(name, &tmp);
782 * Return an unsigned integer value from an environment variable.
785 getenv_uint(const char *name, unsigned int *data)
790 rval = getenv_quad(name, &tmp);
792 *data = (unsigned int) tmp;
797 * Return an int64_t value from an environment variable.
800 getenv_int64(const char *name, int64_t *data)
805 rval = getenv_quad(name, &tmp);
807 *data = (int64_t) tmp;
812 * Return an uint64_t value from an environment variable.
815 getenv_uint64(const char *name, uint64_t *data)
820 rval = getenv_quad(name, &tmp);
822 *data = (uint64_t) tmp;
827 * Return a long value from an environment variable.
830 getenv_long(const char *name, long *data)
835 rval = getenv_quad(name, &tmp);
842 * Return an unsigned long value from an environment variable.
845 getenv_ulong(const char *name, unsigned long *data)
850 rval = getenv_quad(name, &tmp);
852 *data = (unsigned long) tmp;
857 * Return a quad_t value from an environment variable.
860 getenv_quad(const char *name, quad_t *data)
862 char value[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1];
866 if (!getenv_string(name, value, sizeof(value)))
868 iv = strtoq(value, &vtp, 0);
869 if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0'))
893 * Find the next entry after the one which (cp) falls within, return a
894 * pointer to its start or NULL if there are no more.
897 kernenv_next(char *cp)
911 tunable_int_init(void *data)
913 struct tunable_int *d = (struct tunable_int *)data;
915 TUNABLE_INT_FETCH(d->path, d->var);
919 tunable_long_init(void *data)
921 struct tunable_long *d = (struct tunable_long *)data;
923 TUNABLE_LONG_FETCH(d->path, d->var);
927 tunable_ulong_init(void *data)
929 struct tunable_ulong *d = (struct tunable_ulong *)data;
931 TUNABLE_ULONG_FETCH(d->path, d->var);
935 tunable_int64_init(void *data)
937 struct tunable_int64 *d = (struct tunable_int64 *)data;
939 TUNABLE_INT64_FETCH(d->path, d->var);
943 tunable_uint64_init(void *data)
945 struct tunable_uint64 *d = (struct tunable_uint64 *)data;
947 TUNABLE_UINT64_FETCH(d->path, d->var);
951 tunable_quad_init(void *data)
953 struct tunable_quad *d = (struct tunable_quad *)data;
955 TUNABLE_QUAD_FETCH(d->path, d->var);
959 tunable_str_init(void *data)
961 struct tunable_str *d = (struct tunable_str *)data;
963 TUNABLE_STR_FETCH(d->path, d->var, d->size);