2 * SPDX-License-Identifier: BSD-2-Clause
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 #include <sys/param.h>
41 #include <sys/eventhandler.h>
42 #include <sys/systm.h>
44 #include <sys/kernel.h>
45 #include <sys/libkern.h>
46 #include <sys/limits.h>
48 #include <sys/malloc.h>
49 #include <sys/mutex.h>
52 #include <sys/queue.h>
53 #include <sys/sysent.h>
54 #include <sys/sysproto.h>
56 #include <security/mac/mac_framework.h>
58 static char *_getenv_dynamic_locked(const char *name, int *idx);
59 static char *_getenv_dynamic(const char *name, int *idx);
61 static char *kenv_acquire(const char *name);
62 static void kenv_release(const char *buf);
64 static MALLOC_DEFINE(M_KENV, "kenv", "kernel environment");
66 #define KENV_SIZE 512 /* Maximum number of environment strings */
68 static uma_zone_t kenv_zone;
69 static int kenv_mvallen = KENV_MVALLEN;
71 /* pointer to the config-generated static environment */
74 /* pointer to the md-static environment */
76 static int md_env_len;
77 static int md_env_pos;
79 static char *kernenv_next(char *);
81 /* dynamic environment variables */
86 * No need to protect this with a mutex since SYSINITS are single threaded.
90 #define KENV_CHECK if (!dynamic_kenv) \
91 panic("%s: called before SI_SUB_KMEM", __func__)
94 kenv_dump(struct thread *td, char **envp, int what, char *value, int len)
97 size_t done, needed, buflen;
104 MPASS(what == KENV_DUMP || what == KENV_DUMP_LOADER ||
105 what == KENV_DUMP_STATIC);
108 * For non-dynamic kernel environment, we pass in either md_envp or
109 * kern_envp and we must traverse with kernenv_next(). This shuffling
110 * of pointers simplifies the below loop by only differing in how envp
113 if (what != KENV_DUMP) {
119 if (buflen > KENV_SIZE * (KENV_MNAMELEN + kenv_mvallen + 2))
120 buflen = KENV_SIZE * (KENV_MNAMELEN +
122 if (len > 0 && value != NULL)
123 buffer = malloc(buflen, M_TEMP, M_WAITOK|M_ZERO);
125 /* Only take the lock for the dynamic kenv. */
126 if (what == KENV_DUMP)
127 mtx_lock(&kenv_lock);
128 while (*envp != NULL) {
129 len = strlen(*envp) + 1;
131 len = min(len, buflen - done);
133 * If called with a NULL or insufficiently large
134 * buffer, just keep computing the required size.
136 if (value != NULL && buffer != NULL && len > 0) {
137 bcopy(*envp, buffer + done, len);
141 /* Advance the pointer depending on the kenv format. */
142 if (what == KENV_DUMP)
145 senv = kernenv_next(senv);
147 if (what == KENV_DUMP)
148 mtx_unlock(&kenv_lock);
149 if (buffer != NULL) {
150 error = copyout(buffer, value, done);
151 free(buffer, M_TEMP);
153 td->td_retval[0] = ((done == needed) ? 0 : needed);
158 sys_kenv(struct thread *td, struct kenv_args *uap)
164 KASSERT(dynamic_kenv, ("kenv: dynamic_kenv = false"));
171 error = mac_kenv_check_dump(td->td_ucred);
175 return (kenv_dump(td, kenvp, uap->what, uap->value, uap->len));
176 case KENV_DUMP_LOADER:
177 case KENV_DUMP_STATIC:
179 error = mac_kenv_check_dump(td->td_ucred);
183 #ifdef PRESERVE_EARLY_KENV
184 return (kenv_dump(td,
185 uap->what == KENV_DUMP_LOADER ? (char **)md_envp :
186 (char **)kern_envp, uap->what, uap->value, uap->len));
191 error = priv_check(td, PRIV_KENV_SET);
197 error = priv_check(td, PRIV_KENV_UNSET);
203 name = malloc(KENV_MNAMELEN + 1, M_TEMP, M_WAITOK);
205 error = copyinstr(uap->name, name, KENV_MNAMELEN + 1, NULL);
212 error = mac_kenv_check_get(td->td_ucred, name);
216 value = kern_getenv(name);
221 len = strlen(value) + 1;
224 error = copyout(value, uap->value, len);
228 td->td_retval[0] = len;
236 if (len > kenv_mvallen + 1)
237 len = kenv_mvallen + 1;
238 value = malloc(len, M_TEMP, M_WAITOK);
239 error = copyinstr(uap->value, value, len, NULL);
245 error = mac_kenv_check_set(td->td_ucred, name, value);
248 kern_setenv(name, value);
253 error = mac_kenv_check_unset(td->td_ucred, name);
257 error = kern_unsetenv(name);
271 * Populate the initial kernel environment.
273 * This is called very early in MD startup, either to provide a copy of the
274 * environment obtained from a boot loader, or to provide an empty buffer into
275 * which MD code can store an initial environment using kern_setenv() calls.
277 * kern_envp is set to the static_env generated by config(8). This implements
278 * the env keyword described in config(5).
280 * If len is non-zero, the caller is providing an empty buffer. The caller will
281 * subsequently use kern_setenv() to add up to len bytes of initial environment
282 * before the dynamic environment is available.
284 * If len is zero, the caller is providing a pre-loaded buffer containing
285 * environment strings. Additional strings cannot be added until the dynamic
286 * environment is available. The memory pointed to must remain stable at least
287 * until sysinit runs init_dynamic_kenv() and preferably until after SI_SUB_KMEM
288 * is finished so that subr_hints routines may continue to use it until the
289 * environments have been fully merged at the end of the pass. If no initial
290 * environment is available from the boot loader, passing a NULL pointer allows
291 * the static_env to be installed if it is configured. In this case, any call
292 * to kern_setenv() prior to the setup of the dynamic environment will result in
296 init_static_kenv(char *buf, size_t len)
299 KASSERT(!dynamic_kenv, ("kenv: dynamic_kenv already initialized"));
301 * Suitably sized means it must be able to hold at least one empty
302 * variable, otherwise things go belly up if a kern_getenv call is
303 * made without a prior call to kern_setenv as we have a malformed
306 KASSERT(len == 0 || len >= 2,
307 ("kenv: static env must be initialized or suitably sized"));
308 KASSERT(len == 0 || (*buf == '\0' && *(buf + 1) == '\0'),
309 ("kenv: sized buffer must be initially empty"));
312 * We may be called twice, with the second call needed to relocate
313 * md_envp after enabling paging. md_envp is then garbage if it is
314 * not null and the relocation will move it. Discard it so as to
315 * not crash using its old value in our first call to kern_getenv().
317 * The second call gives the same environment as the first except
318 * in silly configurations where the static env disables itself.
320 * Other env calls don't handle possibly-garbage pointers, so must
321 * not be made between enabling paging and calling here.
328 * Give the static environment a chance to disable the loader(8)
329 * environment first. This is done with loader_env.disabled=1.
331 * static_env and static_hints may both be disabled, but in slightly
332 * different ways. For static_env, we just don't setup kern_envp and
333 * it's as if a static env wasn't even provided. For static_hints,
334 * we effectively zero out the buffer to stop the rest of the kernel
335 * from being able to use it.
337 * We're intentionally setting this up so that static_hints.disabled may
338 * be specified in either the MD env or the static env. This keeps us
339 * consistent in our new world view.
341 * As a warning, the static environment may not be disabled in any way
342 * if the static environment has disabled the loader environment.
344 kern_envp = static_env;
345 if (!getenv_is_true("loader_env.disabled")) {
350 if (getenv_is_true("static_env.disabled")) {
355 if (getenv_is_true("static_hints.disabled")) {
356 static_hints[0] = '\0';
357 static_hints[1] = '\0';
361 /* Maximum suffix number appended for duplicate environment variable names. */
362 #define MAXSUFFIX 9999
363 #define SUFFIXLEN strlen("_" __XSTRING(MAXSUFFIX))
366 getfreesuffix(char *cp, size_t *n)
368 size_t len = strlen(cp);
371 ncp = malloc(len + SUFFIXLEN + 1, M_KENV, M_WAITOK);
372 memcpy(ncp, cp, len);
373 for (*n = 1; *n <= MAXSUFFIX; (*n)++) {
374 sprintf(&ncp[len], "_%zu", *n);
375 if (!_getenv_dynamic_locked(ncp, NULL))
380 panic("Too many duplicate kernel environment values: %s", cp);
384 init_dynamic_kenv_from(char *init_env, int *curpos)
386 char *cp, *cpnext, *eqpos, *found;
390 if (init_env && *init_env != '\0') {
393 for (cp = init_env; cp != NULL; cp = cpnext) {
394 cpnext = kernenv_next(cp);
395 len = strlen(cp) + 1;
398 "WARNING: too many kenv strings, ignoring %s\n",
402 if (len > KENV_MNAMELEN + 1 + kenv_mvallen + 1) {
404 "WARNING: too long kenv string, ignoring %s\n",
408 eqpos = strchr(cp, '=');
411 "WARNING: malformed static env value, ignoring %s\n",
417 * Handle duplicates in the environment as we go; we
418 * add the duplicated assignments with _N suffixes.
419 * This ensures that (a) if a variable is set in the
420 * static environment and in the "loader" environment
421 * provided by MD code, the value from the loader will
422 * have the expected variable name and the value from
423 * the static environment will have the suffix; and (b)
424 * if the "loader" environment has the same variable
425 * set multiple times (as is possible with values being
426 * passed via the kernel "command line") the extra
427 * values are visible to code which knows where to look
430 found = _getenv_dynamic_locked(cp, NULL);
432 getfreesuffix(cp, &n);
433 kenvp[i] = malloc(len + SUFFIXLEN,
435 sprintf(kenvp[i++], "%s_%zu=%s", cp, n,
438 kenvp[i] = malloc(len, M_KENV, M_WAITOK);
440 strcpy(kenvp[i++], cp);
443 #ifdef PRESERVE_EARLY_KENV
446 explicit_bzero(cp, len - 1);
454 * Setup the dynamic kernel environment.
457 init_dynamic_kenv(void *data __unused)
462 TUNABLE_INT_FETCH("kenv_mvallen", &kenv_mvallen);
463 size = KENV_MNAMELEN + 1 + kenv_mvallen + 1;
465 kenv_zone = uma_zcreate("kenv", size, NULL, NULL, NULL, NULL,
468 kenvp = malloc((KENV_SIZE + 1) * sizeof(char *), M_KENV,
472 init_dynamic_kenv_from(md_envp, &dynamic_envpos);
473 init_dynamic_kenv_from(kern_envp, &dynamic_envpos);
474 kenvp[dynamic_envpos] = NULL;
476 mtx_init(&kenv_lock, "kernel environment", NULL, MTX_DEF);
479 SYSINIT(kenv, SI_SUB_KMEM + 1, SI_ORDER_FIRST, init_dynamic_kenv, NULL);
485 if (dynamic_kenv && env != NULL) {
486 explicit_bzero(env, strlen(env));
487 uma_zfree(kenv_zone, env);
492 * Internal functions for string lookup.
495 _getenv_dynamic_locked(const char *name, int *idx)
501 for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) {
502 if ((strncmp(cp, name, len) == 0) &&
506 return (cp + len + 1);
513 _getenv_dynamic(const char *name, int *idx)
516 mtx_assert(&kenv_lock, MA_OWNED);
517 return (_getenv_dynamic_locked(name, idx));
521 _getenv_static_from(char *chkenv, const char *name)
526 for (cp = chkenv; cp != NULL; cp = kernenv_next(cp)) {
527 for (ep = cp; (*ep != '=') && (*ep != 0); ep++)
533 if (!strncmp(name, cp, len) && name[len] == 0)
540 _getenv_static(const char *name)
544 val = _getenv_static_from(md_envp, name);
547 val = _getenv_static_from(kern_envp, name);
554 * Look up an environment variable by name.
555 * Return a pointer to the string if found.
556 * The pointer has to be freed with freeenv()
560 kern_getenv(const char *name)
566 len = KENV_MNAMELEN + 1 + kenv_mvallen + 1;
567 ret = uma_zalloc(kenv_zone, M_WAITOK | M_ZERO);
568 mtx_lock(&kenv_lock);
569 cp = _getenv_dynamic(name, NULL);
571 strlcpy(ret, cp, len);
572 mtx_unlock(&kenv_lock);
574 uma_zfree(kenv_zone, ret);
578 ret = _getenv_static(name);
584 * Test if an environment variable is defined.
587 testenv(const char *name)
591 cp = kenv_acquire(name);
600 * Set an environment variable in the MD-static environment. This cannot
601 * feasibly be done on config(8)-generated static environments as they don't
602 * generally include space for extra variables.
605 setenv_static(const char *name, const char *value)
609 if (md_env_pos >= md_env_len)
612 /* Check space for x=y and two nuls */
613 len = strlen(name) + strlen(value);
614 if (len + 3 < md_env_len - md_env_pos) {
615 len = sprintf(&md_envp[md_env_pos], "%s=%s", name, value);
617 md_envp[md_env_pos] = '\0';
625 * Set an environment variable by name.
628 kern_setenv(const char *name, const char *value)
630 char *buf, *cp, *oldenv;
631 int namelen, vallen, i;
633 if (!dynamic_kenv && md_env_len > 0)
634 return (setenv_static(name, value));
638 namelen = strlen(name) + 1;
639 if (namelen > KENV_MNAMELEN + 1)
641 vallen = strlen(value) + 1;
642 if (vallen > kenv_mvallen + 1)
644 buf = malloc(namelen + vallen, M_KENV, M_WAITOK);
645 sprintf(buf, "%s=%s", name, value);
647 mtx_lock(&kenv_lock);
648 cp = _getenv_dynamic(name, &i);
652 mtx_unlock(&kenv_lock);
653 free(oldenv, M_KENV);
655 /* We add the option if it wasn't found */
656 for (i = 0; (cp = kenvp[i]) != NULL; i++)
659 /* Bounds checking */
660 if (i < 0 || i >= KENV_SIZE) {
662 mtx_unlock(&kenv_lock);
668 mtx_unlock(&kenv_lock);
670 EVENTHANDLER_INVOKE(setenv, name);
675 * Unset an environment variable string.
678 kern_unsetenv(const char *name)
685 mtx_lock(&kenv_lock);
686 cp = _getenv_dynamic(name, &i);
689 for (j = i + 1; kenvp[j] != NULL; j++)
690 kenvp[i++] = kenvp[j];
692 mtx_unlock(&kenv_lock);
693 zfree(oldenv, M_KENV);
694 EVENTHANDLER_INVOKE(unsetenv, name);
697 mtx_unlock(&kenv_lock);
702 * Return the internal kenv buffer for the variable name, if it exists.
703 * If the dynamic kenv is initialized and the name is present, return
704 * with kenv_lock held.
707 kenv_acquire(const char *name)
712 mtx_lock(&kenv_lock);
713 value = _getenv_dynamic(name, NULL);
715 mtx_unlock(&kenv_lock);
718 return (_getenv_static(name));
722 * Undo a previous kenv_acquire() operation
725 kenv_release(const char *buf)
727 if ((buf != NULL) && dynamic_kenv)
728 mtx_unlock(&kenv_lock);
732 * Return a string value from an environment variable.
735 getenv_string(const char *name, char *data, int size)
739 cp = kenv_acquire(name);
742 strlcpy(data, cp, size);
750 * Return an array of integers at the given type size and signedness.
753 getenv_array(const char *name, void *pdata, int size, int *psize,
754 int type_size, bool allow_signed)
765 rc = 0; /* assume failure */
767 buf = kenv_acquire(name);
771 /* get maximum number of elements */
776 for (ptr = buf; *ptr != 0; ) {
777 value = strtoq(ptr, &end, 0);
779 /* check if signed numbers are allowed */
780 if (value < 0 && !allow_signed)
783 /* check for invalid value */
787 /* check for valid suffix */
816 /* garbage after numeric value */
820 /* skip till next value, if any */
821 while (*end == '\t' || *end == ',' || *end == ' ')
832 if ((value >> shift) != old)
835 /* check for buffer overflow */
839 /* store value according to type size */
843 if (value < SCHAR_MIN || value > SCHAR_MAX)
846 if (value < 0 || value > UCHAR_MAX)
849 ((uint8_t *)pdata)[n] = (uint8_t)value;
853 if (value < SHRT_MIN || value > SHRT_MAX)
856 if (value < 0 || value > USHRT_MAX)
859 ((uint16_t *)pdata)[n] = (uint16_t)value;
863 if (value < INT_MIN || value > INT_MAX)
866 if (value > UINT_MAX)
869 ((uint32_t *)pdata)[n] = (uint32_t)value;
872 ((uint64_t *)pdata)[n] = (uint64_t)value;
879 *psize = n * type_size;
882 rc = 1; /* success */
889 * Return an integer value from an environment variable.
892 getenv_int(const char *name, int *data)
897 rval = getenv_quad(name, &tmp);
904 * Return an unsigned integer value from an environment variable.
907 getenv_uint(const char *name, unsigned int *data)
912 rval = getenv_quad(name, &tmp);
914 *data = (unsigned int) tmp;
919 * Return an int64_t value from an environment variable.
922 getenv_int64(const char *name, int64_t *data)
927 rval = getenv_quad(name, &tmp);
929 *data = (int64_t) tmp;
934 * Return an uint64_t value from an environment variable.
937 getenv_uint64(const char *name, uint64_t *data)
942 rval = getenv_quad(name, &tmp);
944 *data = (uint64_t) tmp;
949 * Return a long value from an environment variable.
952 getenv_long(const char *name, long *data)
957 rval = getenv_quad(name, &tmp);
964 * Return an unsigned long value from an environment variable.
967 getenv_ulong(const char *name, unsigned long *data)
972 rval = getenv_quad(name, &tmp);
974 *data = (unsigned long) tmp;
979 * Return a quad_t value from an environment variable.
982 getenv_quad(const char *name, quad_t *data)
988 value = kenv_acquire(name);
992 iv = strtoq(value, &vtp, 0);
993 if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0')) {
1018 kenv_release(value);
1023 * Return a boolean value from an environment variable. This can be in
1024 * numerical or string form, i.e. "1" or "true".
1027 getenv_bool(const char *name, bool *data)
1035 val = kern_getenv(name);
1039 if ((strcmp(val, "1") == 0) || (strcasecmp(val, "true") == 0)) {
1042 } else if ((strcmp(val, "0") == 0) || (strcasecmp(val, "false") == 0)) {
1046 /* Spit out a warning for malformed boolean variables. */
1047 printf("Environment variable %s has non-boolean value \"%s\"\n",
1056 * Wrapper around getenv_bool to easily check for true.
1059 getenv_is_true(const char *name)
1063 if (getenv_bool(name, &val) != 0)
1069 * Wrapper around getenv_bool to easily check for false.
1072 getenv_is_false(const char *name)
1076 if (getenv_bool(name, &val) != 0)
1082 * Find the next entry after the one which (cp) falls within, return a
1083 * pointer to its start or NULL if there are no more.
1086 kernenv_next(char *cp)
1100 tunable_int_init(void *data)
1102 struct tunable_int *d = (struct tunable_int *)data;
1104 TUNABLE_INT_FETCH(d->path, d->var);
1108 tunable_long_init(void *data)
1110 struct tunable_long *d = (struct tunable_long *)data;
1112 TUNABLE_LONG_FETCH(d->path, d->var);
1116 tunable_ulong_init(void *data)
1118 struct tunable_ulong *d = (struct tunable_ulong *)data;
1120 TUNABLE_ULONG_FETCH(d->path, d->var);
1124 tunable_int64_init(void *data)
1126 struct tunable_int64 *d = (struct tunable_int64 *)data;
1128 TUNABLE_INT64_FETCH(d->path, d->var);
1132 tunable_uint64_init(void *data)
1134 struct tunable_uint64 *d = (struct tunable_uint64 *)data;
1136 TUNABLE_UINT64_FETCH(d->path, d->var);
1140 tunable_quad_init(void *data)
1142 struct tunable_quad *d = (struct tunable_quad *)data;
1144 TUNABLE_QUAD_FETCH(d->path, d->var);
1148 tunable_bool_init(void *data)
1150 struct tunable_bool *d = (struct tunable_bool *)data;
1152 TUNABLE_BOOL_FETCH(d->path, d->var);
1156 tunable_str_init(void *data)
1158 struct tunable_str *d = (struct tunable_str *)data;
1160 TUNABLE_STR_FETCH(d->path, d->var, d->size);