xref: /freebsd/sys/kern/kern_environment.c (revision c93b6e5fa24ba172ab271432c6692f9cc604e15a)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 1998 Michael Smith
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
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.
15  *
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
26  * SUCH DAMAGE.
27  */
28 
29 /*
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.
33  *
34  * We make these available through the kenv(2) syscall for userland
35  * and through kern_getenv()/freeenv() kern_setenv() kern_unsetenv() testenv() for
36  * the kernel.
37  */
38 
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD$");
41 
42 #include <sys/param.h>
43 #include <sys/proc.h>
44 #include <sys/queue.h>
45 #include <sys/lock.h>
46 #include <sys/malloc.h>
47 #include <sys/mutex.h>
48 #include <sys/priv.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>
54 #include <sys/kenv.h>
55 #include <sys/limits.h>
56 
57 #include <security/mac/mac_framework.h>
58 
59 static char *_getenv_dynamic_locked(const char *name, int *idx);
60 static char *_getenv_dynamic(const char *name, int *idx);
61 
62 static MALLOC_DEFINE(M_KENV, "kenv", "kernel environment");
63 
64 #define KENV_SIZE	512	/* Maximum number of environment strings */
65 
66 /* pointer to the config-generated static environment */
67 char		*kern_envp;
68 
69 /* pointer to the md-static environment */
70 char		*md_envp;
71 static int	md_env_len;
72 static int	md_env_pos;
73 
74 static char	*kernenv_next(char *);
75 
76 /* dynamic environment variables */
77 char		**kenvp;
78 struct mtx	kenv_lock;
79 
80 /*
81  * No need to protect this with a mutex since SYSINITS are single threaded.
82  */
83 bool	dynamic_kenv;
84 
85 #define KENV_CHECK	if (!dynamic_kenv) \
86 			    panic("%s: called before SI_SUB_KMEM", __func__)
87 
88 int
89 sys_kenv(td, uap)
90 	struct thread *td;
91 	struct kenv_args /* {
92 		int what;
93 		const char *name;
94 		char *value;
95 		int len;
96 	} */ *uap;
97 {
98 	char *name, *value, *buffer = NULL;
99 	size_t len, done, needed, buflen;
100 	int error, i;
101 
102 	KASSERT(dynamic_kenv, ("kenv: dynamic_kenv = false"));
103 
104 	error = 0;
105 	if (uap->what == KENV_DUMP) {
106 #ifdef MAC
107 		error = mac_kenv_check_dump(td->td_ucred);
108 		if (error)
109 			return (error);
110 #endif
111 		done = needed = 0;
112 		buflen = uap->len;
113 		if (buflen > KENV_SIZE * (KENV_MNAMELEN + KENV_MVALLEN + 2))
114 			buflen = KENV_SIZE * (KENV_MNAMELEN +
115 			    KENV_MVALLEN + 2);
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;
121 			needed += len;
122 			len = min(len, buflen - done);
123 			/*
124 			 * If called with a NULL or insufficiently large
125 			 * buffer, just keep computing the required size.
126 			 */
127 			if (uap->value != NULL && buffer != NULL && len > 0) {
128 				bcopy(kenvp[i], buffer + done, len);
129 				done += len;
130 			}
131 		}
132 		mtx_unlock(&kenv_lock);
133 		if (buffer != NULL) {
134 			error = copyout(buffer, uap->value, done);
135 			free(buffer, M_TEMP);
136 		}
137 		td->td_retval[0] = ((done == needed) ? 0 : needed);
138 		return (error);
139 	}
140 
141 	switch (uap->what) {
142 	case KENV_SET:
143 		error = priv_check(td, PRIV_KENV_SET);
144 		if (error)
145 			return (error);
146 		break;
147 
148 	case KENV_UNSET:
149 		error = priv_check(td, PRIV_KENV_UNSET);
150 		if (error)
151 			return (error);
152 		break;
153 	}
154 
155 	name = malloc(KENV_MNAMELEN + 1, M_TEMP, M_WAITOK);
156 
157 	error = copyinstr(uap->name, name, KENV_MNAMELEN + 1, NULL);
158 	if (error)
159 		goto done;
160 
161 	switch (uap->what) {
162 	case KENV_GET:
163 #ifdef MAC
164 		error = mac_kenv_check_get(td->td_ucred, name);
165 		if (error)
166 			goto done;
167 #endif
168 		value = kern_getenv(name);
169 		if (value == NULL) {
170 			error = ENOENT;
171 			goto done;
172 		}
173 		len = strlen(value) + 1;
174 		if (len > uap->len)
175 			len = uap->len;
176 		error = copyout(value, uap->value, len);
177 		freeenv(value);
178 		if (error)
179 			goto done;
180 		td->td_retval[0] = len;
181 		break;
182 	case KENV_SET:
183 		len = uap->len;
184 		if (len < 1) {
185 			error = EINVAL;
186 			goto done;
187 		}
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);
192 		if (error) {
193 			free(value, M_TEMP);
194 			goto done;
195 		}
196 #ifdef MAC
197 		error = mac_kenv_check_set(td->td_ucred, name, value);
198 		if (error == 0)
199 #endif
200 			kern_setenv(name, value);
201 		free(value, M_TEMP);
202 		break;
203 	case KENV_UNSET:
204 #ifdef MAC
205 		error = mac_kenv_check_unset(td->td_ucred, name);
206 		if (error)
207 			goto done;
208 #endif
209 		error = kern_unsetenv(name);
210 		if (error)
211 			error = ENOENT;
212 		break;
213 	default:
214 		error = EINVAL;
215 		break;
216 	}
217 done:
218 	free(name, M_TEMP);
219 	return (error);
220 }
221 
222 /*
223  * Populate the initial kernel environment.
224  *
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.
228  *
229  * kern_envp is set to the static_env generated by config(8).  This implements
230  * the env keyword described in config(5).
231  *
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.
235  *
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
245  * a panic.
246  */
247 void
248 init_static_kenv(char *buf, size_t len)
249 {
250 	char *eval;
251 
252 	KASSERT(!dynamic_kenv, ("kenv: dynamic_kenv already initialized"));
253 
254 	/*
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().
259 	 *
260 	 * The second call gives the same environment as the first except
261 	 * in silly configurations where the static env disables itself.
262 	 *
263 	 * Other env calls don't handle possibly-garbage pointers, so must
264 	 * not be made between enabling paging and calling here.
265 	 */
266 	md_envp = NULL;
267 	md_env_len = 0;
268 	md_env_pos = 0;
269 
270 	/*
271 	 * Give the static environment a chance to disable the loader(8)
272 	 * environment first.  This is done with loader_env.disabled=1.
273 	 *
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.
279 	 *
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.
283 	 *
284 	 * As a warning, the static environment may not be disabled in any way
285 	 * if the static environment has disabled the loader environment.
286 	 */
287 	kern_envp = static_env;
288 	eval = kern_getenv("loader_env.disabled");
289 	if (eval == NULL || strcmp(eval, "1") != 0) {
290 		md_envp = buf;
291 		md_env_len = len;
292 		md_env_pos = 0;
293 
294 		eval = kern_getenv("static_env.disabled");
295 		if (eval != NULL && strcmp(eval, "1") == 0) {
296 			kern_envp[0] = '\0';
297 			kern_envp[1] = '\0';
298 		}
299 	}
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';
304 	}
305 }
306 
307 static void
308 init_dynamic_kenv_from(char *init_env, int *curpos)
309 {
310 	char *cp, *cpnext, *eqpos, *found;
311 	size_t len;
312 	int i;
313 
314 	if (init_env && *init_env != '\0') {
315 		found = NULL;
316 		i = *curpos;
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) {
321 				printf(
322 				"WARNING: too long kenv string, ignoring %s\n",
323 				    cp);
324 				goto sanitize;
325 			}
326 			eqpos = strchr(cp, '=');
327 			if (eqpos == NULL) {
328 				printf(
329 				"WARNING: malformed static env value, ignoring %s\n",
330 				    cp);
331 				goto sanitize;
332 			}
333 			*eqpos = 0;
334 			/*
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.
340 			 */
341 			found = _getenv_dynamic_locked(cp, NULL);
342 			*eqpos = '=';
343 			if (found != NULL)
344 				goto sanitize;
345 			if (i > KENV_SIZE) {
346 				printf(
347 				"WARNING: too many kenv strings, ignoring %s\n",
348 				    cp);
349 				goto sanitize;
350 			}
351 
352 			kenvp[i] = malloc(len, M_KENV, M_WAITOK);
353 			strcpy(kenvp[i++], cp);
354 sanitize:
355 			explicit_bzero(cp, len - 1);
356 		}
357 		*curpos = i;
358 	}
359 }
360 
361 /*
362  * Setup the dynamic kernel environment.
363  */
364 static void
365 init_dynamic_kenv(void *data __unused)
366 {
367 	int dynamic_envpos;
368 
369 	kenvp = malloc((KENV_SIZE + 1) * sizeof(char *), M_KENV,
370 		M_WAITOK | M_ZERO);
371 
372 	dynamic_envpos = 0;
373 	init_dynamic_kenv_from(md_envp, &dynamic_envpos);
374 	init_dynamic_kenv_from(kern_envp, &dynamic_envpos);
375 	kenvp[dynamic_envpos] = NULL;
376 
377 	mtx_init(&kenv_lock, "kernel environment", NULL, MTX_DEF);
378 	dynamic_kenv = true;
379 }
380 SYSINIT(kenv, SI_SUB_KMEM + 1, SI_ORDER_FIRST, init_dynamic_kenv, NULL);
381 
382 void
383 freeenv(char *env)
384 {
385 
386 	if (dynamic_kenv && env != NULL) {
387 		explicit_bzero(env, strlen(env));
388 		free(env, M_KENV);
389 	}
390 }
391 
392 /*
393  * Internal functions for string lookup.
394  */
395 static char *
396 _getenv_dynamic_locked(const char *name, int *idx)
397 {
398 	char *cp;
399 	int len, i;
400 
401 	len = strlen(name);
402 	for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) {
403 		if ((strncmp(cp, name, len) == 0) &&
404 		    (cp[len] == '=')) {
405 			if (idx != NULL)
406 				*idx = i;
407 			return (cp + len + 1);
408 		}
409 	}
410 	return (NULL);
411 }
412 
413 static char *
414 _getenv_dynamic(const char *name, int *idx)
415 {
416 
417 	mtx_assert(&kenv_lock, MA_OWNED);
418 	return (_getenv_dynamic_locked(name, idx));
419 }
420 
421 static char *
422 _getenv_static_from(char *chkenv, const char *name)
423 {
424 	char *cp, *ep;
425 	int len;
426 
427 	for (cp = chkenv; cp != NULL; cp = kernenv_next(cp)) {
428 		for (ep = cp; (*ep != '=') && (*ep != 0); ep++)
429 			;
430 		if (*ep != '=')
431 			continue;
432 		len = ep - cp;
433 		ep++;
434 		if (!strncmp(name, cp, len) && name[len] == 0)
435 			return (ep);
436 	}
437 	return (NULL);
438 }
439 
440 static char *
441 _getenv_static(const char *name)
442 {
443 	char *val;
444 
445 	val = _getenv_static_from(md_envp, name);
446 	if (val != NULL)
447 		return (val);
448 	val = _getenv_static_from(kern_envp, name);
449 	if (val != NULL)
450 		return (val);
451 	return (NULL);
452 }
453 
454 /*
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()
458  * after use.
459  */
460 char *
461 kern_getenv(const char *name)
462 {
463 	char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1];
464 	char *ret;
465 
466 	if (dynamic_kenv) {
467 		if (getenv_string(name, buf, sizeof(buf))) {
468 			ret = strdup(buf, M_KENV);
469 		} else {
470 			ret = NULL;
471 			WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
472 			    "getenv");
473 		}
474 	} else
475 		ret = _getenv_static(name);
476 	return (ret);
477 }
478 
479 /*
480  * Test if an environment variable is defined.
481  */
482 int
483 testenv(const char *name)
484 {
485 	char *cp;
486 
487 	if (dynamic_kenv) {
488 		mtx_lock(&kenv_lock);
489 		cp = _getenv_dynamic(name, NULL);
490 		mtx_unlock(&kenv_lock);
491 	} else
492 		cp = _getenv_static(name);
493 	if (cp != NULL)
494 		return (1);
495 	return (0);
496 }
497 
498 /*
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.
502  */
503 static int
504 setenv_static(const char *name, const char *value)
505 {
506 	int len;
507 
508 	if (md_env_pos >= md_env_len)
509 		return (-1);
510 
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);
515 		md_env_pos += len+1;
516 		md_envp[md_env_pos] = '\0';
517 		return (0);
518 	} else
519 		return (-1);
520 
521 }
522 
523 /*
524  * Set an environment variable by name.
525  */
526 int
527 kern_setenv(const char *name, const char *value)
528 {
529 	char *buf, *cp, *oldenv;
530 	int namelen, vallen, i;
531 
532 	if (!dynamic_kenv && md_env_len > 0)
533 		return (setenv_static(name, value));
534 
535 	KENV_CHECK;
536 
537 	namelen = strlen(name) + 1;
538 	if (namelen > KENV_MNAMELEN + 1)
539 		return (-1);
540 	vallen = strlen(value) + 1;
541 	if (vallen > KENV_MVALLEN + 1)
542 		return (-1);
543 	buf = malloc(namelen + vallen, M_KENV, M_WAITOK);
544 	sprintf(buf, "%s=%s", name, value);
545 
546 	mtx_lock(&kenv_lock);
547 	cp = _getenv_dynamic(name, &i);
548 	if (cp != NULL) {
549 		oldenv = kenvp[i];
550 		kenvp[i] = buf;
551 		mtx_unlock(&kenv_lock);
552 		free(oldenv, M_KENV);
553 	} else {
554 		/* We add the option if it wasn't found */
555 		for (i = 0; (cp = kenvp[i]) != NULL; i++)
556 			;
557 
558 		/* Bounds checking */
559 		if (i < 0 || i >= KENV_SIZE) {
560 			free(buf, M_KENV);
561 			mtx_unlock(&kenv_lock);
562 			return (-1);
563 		}
564 
565 		kenvp[i] = buf;
566 		kenvp[i + 1] = NULL;
567 		mtx_unlock(&kenv_lock);
568 	}
569 	return (0);
570 }
571 
572 /*
573  * Unset an environment variable string.
574  */
575 int
576 kern_unsetenv(const char *name)
577 {
578 	char *cp, *oldenv;
579 	int i, j;
580 
581 	KENV_CHECK;
582 
583 	mtx_lock(&kenv_lock);
584 	cp = _getenv_dynamic(name, &i);
585 	if (cp != NULL) {
586 		oldenv = kenvp[i];
587 		for (j = i + 1; kenvp[j] != NULL; j++)
588 			kenvp[i++] = kenvp[j];
589 		kenvp[i] = NULL;
590 		mtx_unlock(&kenv_lock);
591 		explicit_bzero(oldenv, strlen(oldenv));
592 		free(oldenv, M_KENV);
593 		return (0);
594 	}
595 	mtx_unlock(&kenv_lock);
596 	return (-1);
597 }
598 
599 /*
600  * Return a string value from an environment variable.
601  */
602 int
603 getenv_string(const char *name, char *data, int size)
604 {
605 	char *cp;
606 
607 	if (dynamic_kenv) {
608 		mtx_lock(&kenv_lock);
609 		cp = _getenv_dynamic(name, NULL);
610 		if (cp != NULL)
611 			strlcpy(data, cp, size);
612 		mtx_unlock(&kenv_lock);
613 	} else {
614 		cp = _getenv_static(name);
615 		if (cp != NULL)
616 			strlcpy(data, cp, size);
617 	}
618 	return (cp != NULL);
619 }
620 
621 /*
622  * Return an array of integers at the given type size and signedness.
623  */
624 int
625 getenv_array(const char *name, void *pdata, int size, int *psize,
626     int type_size, bool allow_signed)
627 {
628 	char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1];
629 	uint8_t shift;
630 	int64_t value;
631 	int64_t old;
632 	char *end;
633 	char *ptr;
634 	int n;
635 
636 	if (getenv_string(name, buf, sizeof(buf)) == 0)
637 		return (0);
638 
639 	/* get maximum number of elements */
640 	size /= type_size;
641 
642 	n = 0;
643 
644 	for (ptr = buf; *ptr != 0; ) {
645 
646 		value = strtoq(ptr, &end, 0);
647 
648 		/* check if signed numbers are allowed */
649 		if (value < 0 && !allow_signed)
650 			goto error;
651 
652 		/* check for invalid value */
653 		if (ptr == end)
654 			goto error;
655 
656 		/* check for valid suffix */
657 		switch (*end) {
658 		case 't':
659 		case 'T':
660 			shift = 40;
661 			end++;
662 			break;
663 		case 'g':
664 		case 'G':
665 			shift = 30;
666 			end++;
667 			break;
668 		case 'm':
669 		case 'M':
670 			shift = 20;
671 			end++;
672 			break;
673 		case 'k':
674 		case 'K':
675 			shift = 10;
676 			end++;
677 			break;
678 		case ' ':
679 		case '\t':
680 		case ',':
681 		case 0:
682 			shift = 0;
683 			break;
684 		default:
685 			/* garbage after numeric value */
686 			goto error;
687 		}
688 
689 		/* skip till next value, if any */
690 		while (*end == '\t' || *end == ',' || *end == ' ')
691 			end++;
692 
693 		/* update pointer */
694 		ptr = end;
695 
696 		/* apply shift */
697 		old = value;
698 		value <<= shift;
699 
700 		/* overflow check */
701 		if ((value >> shift) != old)
702 			goto error;
703 
704 		/* check for buffer overflow */
705 		if (n >= size)
706 			goto error;
707 
708 		/* store value according to type size */
709 		switch (type_size) {
710 		case 1:
711 			if (allow_signed) {
712 				if (value < SCHAR_MIN || value > SCHAR_MAX)
713 					goto error;
714 			} else {
715 				if (value < 0 || value > UCHAR_MAX)
716 					goto error;
717 			}
718 			((uint8_t *)pdata)[n] = (uint8_t)value;
719 			break;
720 		case 2:
721 			if (allow_signed) {
722 				if (value < SHRT_MIN || value > SHRT_MAX)
723 					goto error;
724 			} else {
725 				if (value < 0 || value > USHRT_MAX)
726 					goto error;
727 			}
728 			((uint16_t *)pdata)[n] = (uint16_t)value;
729 			break;
730 		case 4:
731 			if (allow_signed) {
732 				if (value < INT_MIN || value > INT_MAX)
733 					goto error;
734 			} else {
735 				if (value > UINT_MAX)
736 					goto error;
737 			}
738 			((uint32_t *)pdata)[n] = (uint32_t)value;
739 			break;
740 		case 8:
741 			((uint64_t *)pdata)[n] = (uint64_t)value;
742 			break;
743 		default:
744 			goto error;
745 		}
746 		n++;
747 	}
748 	*psize = n * type_size;
749 
750 	if (n != 0)
751 		return (1);	/* success */
752 error:
753 	return (0);	/* failure */
754 }
755 
756 /*
757  * Return an integer value from an environment variable.
758  */
759 int
760 getenv_int(const char *name, int *data)
761 {
762 	quad_t tmp;
763 	int rval;
764 
765 	rval = getenv_quad(name, &tmp);
766 	if (rval)
767 		*data = (int) tmp;
768 	return (rval);
769 }
770 
771 /*
772  * Return an unsigned integer value from an environment variable.
773  */
774 int
775 getenv_uint(const char *name, unsigned int *data)
776 {
777 	quad_t tmp;
778 	int rval;
779 
780 	rval = getenv_quad(name, &tmp);
781 	if (rval)
782 		*data = (unsigned int) tmp;
783 	return (rval);
784 }
785 
786 /*
787  * Return an int64_t value from an environment variable.
788  */
789 int
790 getenv_int64(const char *name, int64_t *data)
791 {
792 	quad_t tmp;
793 	int64_t rval;
794 
795 	rval = getenv_quad(name, &tmp);
796 	if (rval)
797 		*data = (int64_t) tmp;
798 	return (rval);
799 }
800 
801 /*
802  * Return an uint64_t value from an environment variable.
803  */
804 int
805 getenv_uint64(const char *name, uint64_t *data)
806 {
807 	quad_t tmp;
808 	uint64_t rval;
809 
810 	rval = getenv_quad(name, &tmp);
811 	if (rval)
812 		*data = (uint64_t) tmp;
813 	return (rval);
814 }
815 
816 /*
817  * Return a long value from an environment variable.
818  */
819 int
820 getenv_long(const char *name, long *data)
821 {
822 	quad_t tmp;
823 	int rval;
824 
825 	rval = getenv_quad(name, &tmp);
826 	if (rval)
827 		*data = (long) tmp;
828 	return (rval);
829 }
830 
831 /*
832  * Return an unsigned long value from an environment variable.
833  */
834 int
835 getenv_ulong(const char *name, unsigned long *data)
836 {
837 	quad_t tmp;
838 	int rval;
839 
840 	rval = getenv_quad(name, &tmp);
841 	if (rval)
842 		*data = (unsigned long) tmp;
843 	return (rval);
844 }
845 
846 /*
847  * Return a quad_t value from an environment variable.
848  */
849 int
850 getenv_quad(const char *name, quad_t *data)
851 {
852 	char	value[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1];
853 	char	*vtp;
854 	quad_t	iv;
855 
856 	if (!getenv_string(name, value, sizeof(value)))
857 		return (0);
858 	iv = strtoq(value, &vtp, 0);
859 	if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0'))
860 		return (0);
861 	switch (vtp[0]) {
862 	case 't': case 'T':
863 		iv *= 1024;
864 		/* FALLTHROUGH */
865 	case 'g': case 'G':
866 		iv *= 1024;
867 		/* FALLTHROUGH */
868 	case 'm': case 'M':
869 		iv *= 1024;
870 		/* FALLTHROUGH */
871 	case 'k': case 'K':
872 		iv *= 1024;
873 	case '\0':
874 		break;
875 	default:
876 		return (0);
877 	}
878 	*data = iv;
879 	return (1);
880 }
881 
882 /*
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.
885  */
886 static char *
887 kernenv_next(char *cp)
888 {
889 
890 	if (cp != NULL) {
891 		while (*cp != 0)
892 			cp++;
893 		cp++;
894 		if (*cp == 0)
895 			cp = NULL;
896 	}
897 	return (cp);
898 }
899 
900 void
901 tunable_int_init(void *data)
902 {
903 	struct tunable_int *d = (struct tunable_int *)data;
904 
905 	TUNABLE_INT_FETCH(d->path, d->var);
906 }
907 
908 void
909 tunable_long_init(void *data)
910 {
911 	struct tunable_long *d = (struct tunable_long *)data;
912 
913 	TUNABLE_LONG_FETCH(d->path, d->var);
914 }
915 
916 void
917 tunable_ulong_init(void *data)
918 {
919 	struct tunable_ulong *d = (struct tunable_ulong *)data;
920 
921 	TUNABLE_ULONG_FETCH(d->path, d->var);
922 }
923 
924 void
925 tunable_int64_init(void *data)
926 {
927 	struct tunable_int64 *d = (struct tunable_int64 *)data;
928 
929 	TUNABLE_INT64_FETCH(d->path, d->var);
930 }
931 
932 void
933 tunable_uint64_init(void *data)
934 {
935 	struct tunable_uint64 *d = (struct tunable_uint64 *)data;
936 
937 	TUNABLE_UINT64_FETCH(d->path, d->var);
938 }
939 
940 void
941 tunable_quad_init(void *data)
942 {
943 	struct tunable_quad *d = (struct tunable_quad *)data;
944 
945 	TUNABLE_QUAD_FETCH(d->path, d->var);
946 }
947 
948 void
949 tunable_str_init(void *data)
950 {
951 	struct tunable_str *d = (struct tunable_str *)data;
952 
953 	TUNABLE_STR_FETCH(d->path, d->var, d->size);
954 }
955