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"));
255 * We may be called twice, with the second call needed to relocate
256 * md_envp after enabling paging. md_envp is then garbage if it is
257 * not null and the relocation will move it. Discard it so as to
258 * not crash using its old value in our first call to kern_getenv().
260 * The second call gives the same environment as the first except
261 * in silly configurations where the static env disables itself.
263 * Other env calls don't handle possibly-garbage pointers, so must
264 * not be made between enabling paging and calling here.
271 * Give the static environment a chance to disable the loader(8)
272 * environment first. This is done with loader_env.disabled=1.
274 * static_env and static_hints may both be disabled, but in slightly
275 * different ways. For static_env, we just don't setup kern_envp and
276 * it's as if a static env wasn't even provided. For static_hints,
277 * we effectively zero out the buffer to stop the rest of the kernel
278 * from being able to use it.
280 * We're intentionally setting this up so that static_hints.disabled may
281 * be specified in either the MD env or the static env. This keeps us
282 * consistent in our new world view.
284 * As a warning, the static environment may not be disabled in any way
285 * if the static environment has disabled the loader environment.
287 kern_envp = static_env;
288 eval = kern_getenv("loader_env.disabled");
289 if (eval == NULL || strcmp(eval, "1") != 0) {
294 eval = kern_getenv("static_env.disabled");
295 if (eval != NULL && strcmp(eval, "1") == 0) {
300 eval = kern_getenv("static_hints.disabled");
301 if (eval != NULL && strcmp(eval, "1") == 0) {
302 static_hints[0] = '\0';
303 static_hints[1] = '\0';
308 init_dynamic_kenv_from(char *init_env, int *curpos)
310 char *cp, *cpnext, *eqpos, *found;
314 if (init_env && *init_env != '\0') {
317 for (cp = init_env; cp != NULL; cp = cpnext) {
318 cpnext = kernenv_next(cp);
319 len = strlen(cp) + 1;
320 if (len > KENV_MNAMELEN + 1 + KENV_MVALLEN + 1) {
322 "WARNING: too long kenv string, ignoring %s\n",
326 eqpos = strchr(cp, '=');
329 "WARNING: malformed static env value, ignoring %s\n",
335 * De-dupe the environment as we go. We don't add the
336 * duplicated assignments because config(8) will flip
337 * the order of the static environment around to make
338 * kernel processing match the order of specification
339 * in the kernel config.
341 found = _getenv_dynamic_locked(cp, NULL);
347 "WARNING: too many kenv strings, ignoring %s\n",
352 kenvp[i] = malloc(len, M_KENV, M_WAITOK);
353 strcpy(kenvp[i++], cp);
355 explicit_bzero(cp, len - 1);
362 * Setup the dynamic kernel environment.
365 init_dynamic_kenv(void *data __unused)
369 kenvp = malloc((KENV_SIZE + 1) * sizeof(char *), M_KENV,
373 init_dynamic_kenv_from(md_envp, &dynamic_envpos);
374 init_dynamic_kenv_from(kern_envp, &dynamic_envpos);
375 kenvp[dynamic_envpos] = NULL;
377 mtx_init(&kenv_lock, "kernel environment", NULL, MTX_DEF);
380 SYSINIT(kenv, SI_SUB_KMEM + 1, SI_ORDER_FIRST, init_dynamic_kenv, NULL);
386 if (dynamic_kenv && env != NULL) {
387 explicit_bzero(env, strlen(env));
393 * Internal functions for string lookup.
396 _getenv_dynamic_locked(const char *name, int *idx)
402 for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) {
403 if ((strncmp(cp, name, len) == 0) &&
407 return (cp + len + 1);
414 _getenv_dynamic(const char *name, int *idx)
417 mtx_assert(&kenv_lock, MA_OWNED);
418 return (_getenv_dynamic_locked(name, idx));
422 _getenv_static_from(char *chkenv, const char *name)
427 for (cp = chkenv; cp != NULL; cp = kernenv_next(cp)) {
428 for (ep = cp; (*ep != '=') && (*ep != 0); ep++)
434 if (!strncmp(name, cp, len) && name[len] == 0)
441 _getenv_static(const char *name)
445 val = _getenv_static_from(md_envp, name);
448 val = _getenv_static_from(kern_envp, name);
455 * Look up an environment variable by name.
456 * Return a pointer to the string if found.
457 * The pointer has to be freed with freeenv()
461 kern_getenv(const char *name)
463 char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1];
467 if (getenv_string(name, buf, sizeof(buf))) {
468 ret = strdup(buf, M_KENV);
471 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
475 ret = _getenv_static(name);
480 * Test if an environment variable is defined.
483 testenv(const char *name)
488 mtx_lock(&kenv_lock);
489 cp = _getenv_dynamic(name, NULL);
490 mtx_unlock(&kenv_lock);
492 cp = _getenv_static(name);
499 * Set an environment variable in the MD-static environment. This cannot
500 * feasibly be done on config(8)-generated static environments as they don't
501 * generally include space for extra variables.
504 setenv_static(const char *name, const char *value)
508 if (md_env_pos >= md_env_len)
511 /* Check space for x=y and two nuls */
512 len = strlen(name) + strlen(value);
513 if (len + 3 < md_env_len - md_env_pos) {
514 len = sprintf(&md_envp[md_env_pos], "%s=%s", name, value);
516 md_envp[md_env_pos] = '\0';
524 * Set an environment variable by name.
527 kern_setenv(const char *name, const char *value)
529 char *buf, *cp, *oldenv;
530 int namelen, vallen, i;
532 if (!dynamic_kenv && md_env_len > 0)
533 return (setenv_static(name, value));
537 namelen = strlen(name) + 1;
538 if (namelen > KENV_MNAMELEN + 1)
540 vallen = strlen(value) + 1;
541 if (vallen > KENV_MVALLEN + 1)
543 buf = malloc(namelen + vallen, M_KENV, M_WAITOK);
544 sprintf(buf, "%s=%s", name, value);
546 mtx_lock(&kenv_lock);
547 cp = _getenv_dynamic(name, &i);
551 mtx_unlock(&kenv_lock);
552 free(oldenv, M_KENV);
554 /* We add the option if it wasn't found */
555 for (i = 0; (cp = kenvp[i]) != NULL; i++)
558 /* Bounds checking */
559 if (i < 0 || i >= KENV_SIZE) {
561 mtx_unlock(&kenv_lock);
567 mtx_unlock(&kenv_lock);
573 * Unset an environment variable string.
576 kern_unsetenv(const char *name)
583 mtx_lock(&kenv_lock);
584 cp = _getenv_dynamic(name, &i);
587 for (j = i + 1; kenvp[j] != NULL; j++)
588 kenvp[i++] = kenvp[j];
590 mtx_unlock(&kenv_lock);
591 explicit_bzero(oldenv, strlen(oldenv));
592 free(oldenv, M_KENV);
595 mtx_unlock(&kenv_lock);
600 * Return a string value from an environment variable.
603 getenv_string(const char *name, char *data, int size)
608 mtx_lock(&kenv_lock);
609 cp = _getenv_dynamic(name, NULL);
611 strlcpy(data, cp, size);
612 mtx_unlock(&kenv_lock);
614 cp = _getenv_static(name);
616 strlcpy(data, cp, size);
622 * Return an array of integers at the given type size and signedness.
625 getenv_array(const char *name, void *pdata, int size, int *psize,
626 int type_size, bool allow_signed)
628 char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1];
636 if (getenv_string(name, buf, sizeof(buf)) == 0)
639 /* get maximum number of elements */
644 for (ptr = buf; *ptr != 0; ) {
646 value = strtoq(ptr, &end, 0);
648 /* check if signed numbers are allowed */
649 if (value < 0 && !allow_signed)
652 /* check for invalid value */
656 /* check for valid suffix */
685 /* garbage after numeric value */
689 /* skip till next value, if any */
690 while (*end == '\t' || *end == ',' || *end == ' ')
701 if ((value >> shift) != old)
704 /* check for buffer overflow */
708 /* store value according to type size */
712 if (value < SCHAR_MIN || value > SCHAR_MAX)
715 if (value < 0 || value > UCHAR_MAX)
718 ((uint8_t *)pdata)[n] = (uint8_t)value;
722 if (value < SHRT_MIN || value > SHRT_MAX)
725 if (value < 0 || value > USHRT_MAX)
728 ((uint16_t *)pdata)[n] = (uint16_t)value;
732 if (value < INT_MIN || value > INT_MAX)
735 if (value > UINT_MAX)
738 ((uint32_t *)pdata)[n] = (uint32_t)value;
741 ((uint64_t *)pdata)[n] = (uint64_t)value;
748 *psize = n * type_size;
751 return (1); /* success */
753 return (0); /* failure */
757 * Return an integer value from an environment variable.
760 getenv_int(const char *name, int *data)
765 rval = getenv_quad(name, &tmp);
772 * Return an unsigned integer value from an environment variable.
775 getenv_uint(const char *name, unsigned int *data)
780 rval = getenv_quad(name, &tmp);
782 *data = (unsigned int) tmp;
787 * Return an int64_t value from an environment variable.
790 getenv_int64(const char *name, int64_t *data)
795 rval = getenv_quad(name, &tmp);
797 *data = (int64_t) tmp;
802 * Return an uint64_t value from an environment variable.
805 getenv_uint64(const char *name, uint64_t *data)
810 rval = getenv_quad(name, &tmp);
812 *data = (uint64_t) tmp;
817 * Return a long value from an environment variable.
820 getenv_long(const char *name, long *data)
825 rval = getenv_quad(name, &tmp);
832 * Return an unsigned long value from an environment variable.
835 getenv_ulong(const char *name, unsigned long *data)
840 rval = getenv_quad(name, &tmp);
842 *data = (unsigned long) tmp;
847 * Return a quad_t value from an environment variable.
850 getenv_quad(const char *name, quad_t *data)
852 char value[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1];
856 if (!getenv_string(name, value, sizeof(value)))
858 iv = strtoq(value, &vtp, 0);
859 if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0'))
883 * Find the next entry after the one which (cp) falls within, return a
884 * pointer to its start or NULL if there are no more.
887 kernenv_next(char *cp)
901 tunable_int_init(void *data)
903 struct tunable_int *d = (struct tunable_int *)data;
905 TUNABLE_INT_FETCH(d->path, d->var);
909 tunable_long_init(void *data)
911 struct tunable_long *d = (struct tunable_long *)data;
913 TUNABLE_LONG_FETCH(d->path, d->var);
917 tunable_ulong_init(void *data)
919 struct tunable_ulong *d = (struct tunable_ulong *)data;
921 TUNABLE_ULONG_FETCH(d->path, d->var);
925 tunable_int64_init(void *data)
927 struct tunable_int64 *d = (struct tunable_int64 *)data;
929 TUNABLE_INT64_FETCH(d->path, d->var);
933 tunable_uint64_init(void *data)
935 struct tunable_uint64 *d = (struct tunable_uint64 *)data;
937 TUNABLE_UINT64_FETCH(d->path, d->var);
941 tunable_quad_init(void *data)
943 struct tunable_quad *d = (struct tunable_quad *)data;
945 TUNABLE_QUAD_FETCH(d->path, d->var);
949 tunable_str_init(void *data)
951 struct tunable_str *d = (struct tunable_str *)data;
953 TUNABLE_STR_FETCH(d->path, d->var, d->size);