xref: /freebsd/sys/kern/kern_environment.c (revision eac7052fdebb90caf2f653e06187bdbca837b9c7)
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 char *kenv_acquire(const char *name);
63 static void kenv_release(const char *buf);
64 
65 static MALLOC_DEFINE(M_KENV, "kenv", "kernel environment");
66 
67 #define KENV_SIZE	512	/* Maximum number of environment strings */
68 
69 static uma_zone_t kenv_zone;
70 static int	kenv_mvallen = KENV_MVALLEN;
71 
72 /* pointer to the config-generated static environment */
73 char		*kern_envp;
74 
75 /* pointer to the md-static environment */
76 char		*md_envp;
77 static int	md_env_len;
78 static int	md_env_pos;
79 
80 static char	*kernenv_next(char *);
81 
82 /* dynamic environment variables */
83 char		**kenvp;
84 struct mtx	kenv_lock;
85 
86 /*
87  * No need to protect this with a mutex since SYSINITS are single threaded.
88  */
89 bool	dynamic_kenv;
90 
91 #define KENV_CHECK	if (!dynamic_kenv) \
92 			    panic("%s: called before SI_SUB_KMEM", __func__)
93 
94 int
95 sys_kenv(td, uap)
96 	struct thread *td;
97 	struct kenv_args /* {
98 		int what;
99 		const char *name;
100 		char *value;
101 		int len;
102 	} */ *uap;
103 {
104 	char *name, *value, *buffer = NULL;
105 	size_t len, done, needed, buflen;
106 	int error, i;
107 
108 	KASSERT(dynamic_kenv, ("kenv: dynamic_kenv = false"));
109 
110 	error = 0;
111 	if (uap->what == KENV_DUMP) {
112 #ifdef MAC
113 		error = mac_kenv_check_dump(td->td_ucred);
114 		if (error)
115 			return (error);
116 #endif
117 		done = needed = 0;
118 		buflen = uap->len;
119 		if (buflen > KENV_SIZE * (KENV_MNAMELEN + kenv_mvallen + 2))
120 			buflen = KENV_SIZE * (KENV_MNAMELEN +
121 			    kenv_mvallen + 2);
122 		if (uap->len > 0 && uap->value != NULL)
123 			buffer = malloc(buflen, M_TEMP, M_WAITOK|M_ZERO);
124 		mtx_lock(&kenv_lock);
125 		for (i = 0; kenvp[i] != NULL; i++) {
126 			len = strlen(kenvp[i]) + 1;
127 			needed += len;
128 			len = min(len, buflen - done);
129 			/*
130 			 * If called with a NULL or insufficiently large
131 			 * buffer, just keep computing the required size.
132 			 */
133 			if (uap->value != NULL && buffer != NULL && len > 0) {
134 				bcopy(kenvp[i], buffer + done, len);
135 				done += len;
136 			}
137 		}
138 		mtx_unlock(&kenv_lock);
139 		if (buffer != NULL) {
140 			error = copyout(buffer, uap->value, done);
141 			free(buffer, M_TEMP);
142 		}
143 		td->td_retval[0] = ((done == needed) ? 0 : needed);
144 		return (error);
145 	}
146 
147 	switch (uap->what) {
148 	case KENV_SET:
149 		error = priv_check(td, PRIV_KENV_SET);
150 		if (error)
151 			return (error);
152 		break;
153 
154 	case KENV_UNSET:
155 		error = priv_check(td, PRIV_KENV_UNSET);
156 		if (error)
157 			return (error);
158 		break;
159 	}
160 
161 	name = malloc(KENV_MNAMELEN + 1, M_TEMP, M_WAITOK);
162 
163 	error = copyinstr(uap->name, name, KENV_MNAMELEN + 1, NULL);
164 	if (error)
165 		goto done;
166 
167 	switch (uap->what) {
168 	case KENV_GET:
169 #ifdef MAC
170 		error = mac_kenv_check_get(td->td_ucred, name);
171 		if (error)
172 			goto done;
173 #endif
174 		value = kern_getenv(name);
175 		if (value == NULL) {
176 			error = ENOENT;
177 			goto done;
178 		}
179 		len = strlen(value) + 1;
180 		if (len > uap->len)
181 			len = uap->len;
182 		error = copyout(value, uap->value, len);
183 		freeenv(value);
184 		if (error)
185 			goto done;
186 		td->td_retval[0] = len;
187 		break;
188 	case KENV_SET:
189 		len = uap->len;
190 		if (len < 1) {
191 			error = EINVAL;
192 			goto done;
193 		}
194 		if (len > kenv_mvallen + 1)
195 			len = kenv_mvallen + 1;
196 		value = malloc(len, M_TEMP, M_WAITOK);
197 		error = copyinstr(uap->value, value, len, NULL);
198 		if (error) {
199 			free(value, M_TEMP);
200 			goto done;
201 		}
202 #ifdef MAC
203 		error = mac_kenv_check_set(td->td_ucred, name, value);
204 		if (error == 0)
205 #endif
206 			kern_setenv(name, value);
207 		free(value, M_TEMP);
208 		break;
209 	case KENV_UNSET:
210 #ifdef MAC
211 		error = mac_kenv_check_unset(td->td_ucred, name);
212 		if (error)
213 			goto done;
214 #endif
215 		error = kern_unsetenv(name);
216 		if (error)
217 			error = ENOENT;
218 		break;
219 	default:
220 		error = EINVAL;
221 		break;
222 	}
223 done:
224 	free(name, M_TEMP);
225 	return (error);
226 }
227 
228 /*
229  * Populate the initial kernel environment.
230  *
231  * This is called very early in MD startup, either to provide a copy of the
232  * environment obtained from a boot loader, or to provide an empty buffer into
233  * which MD code can store an initial environment using kern_setenv() calls.
234  *
235  * kern_envp is set to the static_env generated by config(8).  This implements
236  * the env keyword described in config(5).
237  *
238  * If len is non-zero, the caller is providing an empty buffer.  The caller will
239  * subsequently use kern_setenv() to add up to len bytes of initial environment
240  * before the dynamic environment is available.
241  *
242  * If len is zero, the caller is providing a pre-loaded buffer containing
243  * environment strings.  Additional strings cannot be added until the dynamic
244  * environment is available.  The memory pointed to must remain stable at least
245  * until sysinit runs init_dynamic_kenv() and preferably until after SI_SUB_KMEM
246  * is finished so that subr_hints routines may continue to use it until the
247  * environments have been fully merged at the end of the pass.  If no initial
248  * environment is available from the boot loader, passing a NULL pointer allows
249  * the static_env to be installed if it is configured.  In this case, any call
250  * to kern_setenv() prior to the setup of the dynamic environment will result in
251  * a panic.
252  */
253 void
254 init_static_kenv(char *buf, size_t len)
255 {
256 	char *eval;
257 
258 	KASSERT(!dynamic_kenv, ("kenv: dynamic_kenv already initialized"));
259 	/*
260 	 * Suitably sized means it must be able to hold at least one empty
261 	 * variable, otherwise things go belly up if a kern_getenv call is
262 	 * made without a prior call to kern_setenv as we have a malformed
263 	 * environment.
264 	 */
265 	KASSERT(len == 0 || len >= 2,
266 	    ("kenv: static env must be initialized or suitably sized"));
267 	KASSERT(len == 0 || (*buf == '\0' && *(buf + 1) == '\0'),
268 	    ("kenv: sized buffer must be initially empty"));
269 
270 	/*
271 	 * We may be called twice, with the second call needed to relocate
272 	 * md_envp after enabling paging.  md_envp is then garbage if it is
273 	 * not null and the relocation will move it.  Discard it so as to
274 	 * not crash using its old value in our first call to kern_getenv().
275 	 *
276 	 * The second call gives the same environment as the first except
277 	 * in silly configurations where the static env disables itself.
278 	 *
279 	 * Other env calls don't handle possibly-garbage pointers, so must
280 	 * not be made between enabling paging and calling here.
281 	 */
282 	md_envp = NULL;
283 	md_env_len = 0;
284 	md_env_pos = 0;
285 
286 	/*
287 	 * Give the static environment a chance to disable the loader(8)
288 	 * environment first.  This is done with loader_env.disabled=1.
289 	 *
290 	 * static_env and static_hints may both be disabled, but in slightly
291 	 * different ways.  For static_env, we just don't setup kern_envp and
292 	 * it's as if a static env wasn't even provided.  For static_hints,
293 	 * we effectively zero out the buffer to stop the rest of the kernel
294 	 * from being able to use it.
295 	 *
296 	 * We're intentionally setting this up so that static_hints.disabled may
297 	 * be specified in either the MD env or the static env. This keeps us
298 	 * consistent in our new world view.
299 	 *
300 	 * As a warning, the static environment may not be disabled in any way
301 	 * if the static environment has disabled the loader environment.
302 	 */
303 	kern_envp = static_env;
304 	eval = kern_getenv("loader_env.disabled");
305 	if (eval == NULL || strcmp(eval, "1") != 0) {
306 		md_envp = buf;
307 		md_env_len = len;
308 		md_env_pos = 0;
309 
310 		eval = kern_getenv("static_env.disabled");
311 		if (eval != NULL && strcmp(eval, "1") == 0) {
312 			kern_envp[0] = '\0';
313 			kern_envp[1] = '\0';
314 		}
315 	}
316 	eval = kern_getenv("static_hints.disabled");
317 	if (eval != NULL && strcmp(eval, "1") == 0) {
318 		static_hints[0] = '\0';
319 		static_hints[1] = '\0';
320 	}
321 }
322 
323 static void
324 init_dynamic_kenv_from(char *init_env, int *curpos)
325 {
326 	char *cp, *cpnext, *eqpos, *found;
327 	size_t len;
328 	int i;
329 
330 	if (init_env && *init_env != '\0') {
331 		found = NULL;
332 		i = *curpos;
333 		for (cp = init_env; cp != NULL; cp = cpnext) {
334 			cpnext = kernenv_next(cp);
335 			len = strlen(cp) + 1;
336 			if (len > KENV_MNAMELEN + 1 + kenv_mvallen + 1) {
337 				printf(
338 				"WARNING: too long kenv string, ignoring %s\n",
339 				    cp);
340 				goto sanitize;
341 			}
342 			eqpos = strchr(cp, '=');
343 			if (eqpos == NULL) {
344 				printf(
345 				"WARNING: malformed static env value, ignoring %s\n",
346 				    cp);
347 				goto sanitize;
348 			}
349 			*eqpos = 0;
350 			/*
351 			 * De-dupe the environment as we go.  We don't add the
352 			 * duplicated assignments because config(8) will flip
353 			 * the order of the static environment around to make
354 			 * kernel processing match the order of specification
355 			 * in the kernel config.
356 			 */
357 			found = _getenv_dynamic_locked(cp, NULL);
358 			*eqpos = '=';
359 			if (found != NULL)
360 				goto sanitize;
361 			if (i > KENV_SIZE) {
362 				printf(
363 				"WARNING: too many kenv strings, ignoring %s\n",
364 				    cp);
365 				goto sanitize;
366 			}
367 
368 			kenvp[i] = malloc(len, M_KENV, M_WAITOK);
369 			strcpy(kenvp[i++], cp);
370 sanitize:
371 			explicit_bzero(cp, len - 1);
372 		}
373 		*curpos = i;
374 	}
375 }
376 
377 /*
378  * Setup the dynamic kernel environment.
379  */
380 static void
381 init_dynamic_kenv(void *data __unused)
382 {
383 	int dynamic_envpos;
384 	int size;
385 
386 	TUNABLE_INT_FETCH("kenv_mvallen", &kenv_mvallen);
387 	size = KENV_MNAMELEN + 1 + kenv_mvallen + 1;
388 
389 	kenv_zone = uma_zcreate("kenv", size, NULL, NULL, NULL, NULL,
390 	    UMA_ALIGN_PTR, 0);
391 
392 	kenvp = malloc((KENV_SIZE + 1) * sizeof(char *), M_KENV,
393 		M_WAITOK | M_ZERO);
394 
395 	dynamic_envpos = 0;
396 	init_dynamic_kenv_from(md_envp, &dynamic_envpos);
397 	init_dynamic_kenv_from(kern_envp, &dynamic_envpos);
398 	kenvp[dynamic_envpos] = NULL;
399 
400 	mtx_init(&kenv_lock, "kernel environment", NULL, MTX_DEF);
401 	dynamic_kenv = true;
402 }
403 SYSINIT(kenv, SI_SUB_KMEM + 1, SI_ORDER_FIRST, init_dynamic_kenv, NULL);
404 
405 void
406 freeenv(char *env)
407 {
408 
409 	if (dynamic_kenv && env != NULL) {
410 		explicit_bzero(env, strlen(env));
411 		uma_zfree(kenv_zone, env);
412 	}
413 }
414 
415 /*
416  * Internal functions for string lookup.
417  */
418 static char *
419 _getenv_dynamic_locked(const char *name, int *idx)
420 {
421 	char *cp;
422 	int len, i;
423 
424 	len = strlen(name);
425 	for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) {
426 		if ((strncmp(cp, name, len) == 0) &&
427 		    (cp[len] == '=')) {
428 			if (idx != NULL)
429 				*idx = i;
430 			return (cp + len + 1);
431 		}
432 	}
433 	return (NULL);
434 }
435 
436 static char *
437 _getenv_dynamic(const char *name, int *idx)
438 {
439 
440 	mtx_assert(&kenv_lock, MA_OWNED);
441 	return (_getenv_dynamic_locked(name, idx));
442 }
443 
444 static char *
445 _getenv_static_from(char *chkenv, const char *name)
446 {
447 	char *cp, *ep;
448 	int len;
449 
450 	for (cp = chkenv; cp != NULL; cp = kernenv_next(cp)) {
451 		for (ep = cp; (*ep != '=') && (*ep != 0); ep++)
452 			;
453 		if (*ep != '=')
454 			continue;
455 		len = ep - cp;
456 		ep++;
457 		if (!strncmp(name, cp, len) && name[len] == 0)
458 			return (ep);
459 	}
460 	return (NULL);
461 }
462 
463 static char *
464 _getenv_static(const char *name)
465 {
466 	char *val;
467 
468 	val = _getenv_static_from(md_envp, name);
469 	if (val != NULL)
470 		return (val);
471 	val = _getenv_static_from(kern_envp, name);
472 	if (val != NULL)
473 		return (val);
474 	return (NULL);
475 }
476 
477 /*
478  * Look up an environment variable by name.
479  * Return a pointer to the string if found.
480  * The pointer has to be freed with freeenv()
481  * after use.
482  */
483 char *
484 kern_getenv(const char *name)
485 {
486 	char *cp, *ret;
487 	int len;
488 
489 	if (dynamic_kenv) {
490 		len = KENV_MNAMELEN + 1 + kenv_mvallen + 1;
491 		ret = uma_zalloc(kenv_zone, M_WAITOK | M_ZERO);
492 		mtx_lock(&kenv_lock);
493 		cp = _getenv_dynamic(name, NULL);
494 		if (cp != NULL)
495 			strlcpy(ret, cp, len);
496 		mtx_unlock(&kenv_lock);
497 		if (cp == NULL) {
498 			uma_zfree(kenv_zone, ret);
499 			ret = NULL;
500 		}
501 	} else
502 		ret = _getenv_static(name);
503 
504 	return (ret);
505 }
506 
507 /*
508  * Test if an environment variable is defined.
509  */
510 int
511 testenv(const char *name)
512 {
513 	char *cp;
514 
515 	cp = kenv_acquire(name);
516 	kenv_release(cp);
517 
518 	if (cp != NULL)
519 		return (1);
520 	return (0);
521 }
522 
523 /*
524  * Set an environment variable in the MD-static environment.  This cannot
525  * feasibly be done on config(8)-generated static environments as they don't
526  * generally include space for extra variables.
527  */
528 static int
529 setenv_static(const char *name, const char *value)
530 {
531 	int len;
532 
533 	if (md_env_pos >= md_env_len)
534 		return (-1);
535 
536 	/* Check space for x=y and two nuls */
537 	len = strlen(name) + strlen(value);
538 	if (len + 3 < md_env_len - md_env_pos) {
539 		len = sprintf(&md_envp[md_env_pos], "%s=%s", name, value);
540 		md_env_pos += len+1;
541 		md_envp[md_env_pos] = '\0';
542 		return (0);
543 	} else
544 		return (-1);
545 
546 }
547 
548 /*
549  * Set an environment variable by name.
550  */
551 int
552 kern_setenv(const char *name, const char *value)
553 {
554 	char *buf, *cp, *oldenv;
555 	int namelen, vallen, i;
556 
557 	if (!dynamic_kenv && md_env_len > 0)
558 		return (setenv_static(name, value));
559 
560 	KENV_CHECK;
561 
562 	namelen = strlen(name) + 1;
563 	if (namelen > KENV_MNAMELEN + 1)
564 		return (-1);
565 	vallen = strlen(value) + 1;
566 	if (vallen > kenv_mvallen + 1)
567 		return (-1);
568 	buf = malloc(namelen + vallen, M_KENV, M_WAITOK);
569 	sprintf(buf, "%s=%s", name, value);
570 
571 	mtx_lock(&kenv_lock);
572 	cp = _getenv_dynamic(name, &i);
573 	if (cp != NULL) {
574 		oldenv = kenvp[i];
575 		kenvp[i] = buf;
576 		mtx_unlock(&kenv_lock);
577 		free(oldenv, M_KENV);
578 	} else {
579 		/* We add the option if it wasn't found */
580 		for (i = 0; (cp = kenvp[i]) != NULL; i++)
581 			;
582 
583 		/* Bounds checking */
584 		if (i < 0 || i >= KENV_SIZE) {
585 			free(buf, M_KENV);
586 			mtx_unlock(&kenv_lock);
587 			return (-1);
588 		}
589 
590 		kenvp[i] = buf;
591 		kenvp[i + 1] = NULL;
592 		mtx_unlock(&kenv_lock);
593 	}
594 	return (0);
595 }
596 
597 /*
598  * Unset an environment variable string.
599  */
600 int
601 kern_unsetenv(const char *name)
602 {
603 	char *cp, *oldenv;
604 	int i, j;
605 
606 	KENV_CHECK;
607 
608 	mtx_lock(&kenv_lock);
609 	cp = _getenv_dynamic(name, &i);
610 	if (cp != NULL) {
611 		oldenv = kenvp[i];
612 		for (j = i + 1; kenvp[j] != NULL; j++)
613 			kenvp[i++] = kenvp[j];
614 		kenvp[i] = NULL;
615 		mtx_unlock(&kenv_lock);
616 		zfree(oldenv, M_KENV);
617 		return (0);
618 	}
619 	mtx_unlock(&kenv_lock);
620 	return (-1);
621 }
622 
623 /*
624  * Return the internal kenv buffer for the variable name, if it exists.
625  * If the dynamic kenv is initialized and the name is present, return
626  * with kenv_lock held.
627  */
628 static char *
629 kenv_acquire(const char *name)
630 {
631 	char *value;
632 
633 	if (dynamic_kenv) {
634 		mtx_lock(&kenv_lock);
635 		value = _getenv_dynamic(name, NULL);
636 		if (value == NULL)
637 			mtx_unlock(&kenv_lock);
638 		return (value);
639 	} else
640 		return (_getenv_static(name));
641 }
642 
643 /*
644  * Undo a previous kenv_acquire() operation
645  */
646 static void
647 kenv_release(const char *buf)
648 {
649 	if ((buf != NULL) && dynamic_kenv)
650 		mtx_unlock(&kenv_lock);
651 }
652 
653 /*
654  * Return a string value from an environment variable.
655  */
656 int
657 getenv_string(const char *name, char *data, int size)
658 {
659 	char *cp;
660 
661 	cp = kenv_acquire(name);
662 
663 	if (cp != NULL)
664 		strlcpy(data, cp, size);
665 
666 	kenv_release(cp);
667 
668 	return (cp != NULL);
669 }
670 
671 /*
672  * Return an array of integers at the given type size and signedness.
673  */
674 int
675 getenv_array(const char *name, void *pdata, int size, int *psize,
676     int type_size, bool allow_signed)
677 {
678 	uint8_t shift;
679 	int64_t value;
680 	int64_t old;
681 	const char *buf;
682 	char *end;
683 	const char *ptr;
684 	int n;
685 	int rc;
686 
687 	rc = 0;			  /* assume failure */
688 
689 	buf = kenv_acquire(name);
690 	if (buf == NULL)
691 		goto error;
692 
693 	/* get maximum number of elements */
694 	size /= type_size;
695 
696 	n = 0;
697 
698 	for (ptr = buf; *ptr != 0; ) {
699 		value = strtoq(ptr, &end, 0);
700 
701 		/* check if signed numbers are allowed */
702 		if (value < 0 && !allow_signed)
703 			goto error;
704 
705 		/* check for invalid value */
706 		if (ptr == end)
707 			goto error;
708 
709 		/* check for valid suffix */
710 		switch (*end) {
711 		case 't':
712 		case 'T':
713 			shift = 40;
714 			end++;
715 			break;
716 		case 'g':
717 		case 'G':
718 			shift = 30;
719 			end++;
720 			break;
721 		case 'm':
722 		case 'M':
723 			shift = 20;
724 			end++;
725 			break;
726 		case 'k':
727 		case 'K':
728 			shift = 10;
729 			end++;
730 			break;
731 		case ' ':
732 		case '\t':
733 		case ',':
734 		case 0:
735 			shift = 0;
736 			break;
737 		default:
738 			/* garbage after numeric value */
739 			goto error;
740 		}
741 
742 		/* skip till next value, if any */
743 		while (*end == '\t' || *end == ',' || *end == ' ')
744 			end++;
745 
746 		/* update pointer */
747 		ptr = end;
748 
749 		/* apply shift */
750 		old = value;
751 		value <<= shift;
752 
753 		/* overflow check */
754 		if ((value >> shift) != old)
755 			goto error;
756 
757 		/* check for buffer overflow */
758 		if (n >= size)
759 			goto error;
760 
761 		/* store value according to type size */
762 		switch (type_size) {
763 		case 1:
764 			if (allow_signed) {
765 				if (value < SCHAR_MIN || value > SCHAR_MAX)
766 					goto error;
767 			} else {
768 				if (value < 0 || value > UCHAR_MAX)
769 					goto error;
770 			}
771 			((uint8_t *)pdata)[n] = (uint8_t)value;
772 			break;
773 		case 2:
774 			if (allow_signed) {
775 				if (value < SHRT_MIN || value > SHRT_MAX)
776 					goto error;
777 			} else {
778 				if (value < 0 || value > USHRT_MAX)
779 					goto error;
780 			}
781 			((uint16_t *)pdata)[n] = (uint16_t)value;
782 			break;
783 		case 4:
784 			if (allow_signed) {
785 				if (value < INT_MIN || value > INT_MAX)
786 					goto error;
787 			} else {
788 				if (value > UINT_MAX)
789 					goto error;
790 			}
791 			((uint32_t *)pdata)[n] = (uint32_t)value;
792 			break;
793 		case 8:
794 			((uint64_t *)pdata)[n] = (uint64_t)value;
795 			break;
796 		default:
797 			goto error;
798 		}
799 		n++;
800 	}
801 	*psize = n * type_size;
802 
803 	if (n != 0)
804 		rc = 1;	/* success */
805 error:
806 	kenv_release(buf);
807 	return (rc);
808 }
809 
810 /*
811  * Return an integer value from an environment variable.
812  */
813 int
814 getenv_int(const char *name, int *data)
815 {
816 	quad_t tmp;
817 	int rval;
818 
819 	rval = getenv_quad(name, &tmp);
820 	if (rval)
821 		*data = (int) tmp;
822 	return (rval);
823 }
824 
825 /*
826  * Return an unsigned integer value from an environment variable.
827  */
828 int
829 getenv_uint(const char *name, unsigned int *data)
830 {
831 	quad_t tmp;
832 	int rval;
833 
834 	rval = getenv_quad(name, &tmp);
835 	if (rval)
836 		*data = (unsigned int) tmp;
837 	return (rval);
838 }
839 
840 /*
841  * Return an int64_t value from an environment variable.
842  */
843 int
844 getenv_int64(const char *name, int64_t *data)
845 {
846 	quad_t tmp;
847 	int64_t rval;
848 
849 	rval = getenv_quad(name, &tmp);
850 	if (rval)
851 		*data = (int64_t) tmp;
852 	return (rval);
853 }
854 
855 /*
856  * Return an uint64_t value from an environment variable.
857  */
858 int
859 getenv_uint64(const char *name, uint64_t *data)
860 {
861 	quad_t tmp;
862 	uint64_t rval;
863 
864 	rval = getenv_quad(name, &tmp);
865 	if (rval)
866 		*data = (uint64_t) tmp;
867 	return (rval);
868 }
869 
870 /*
871  * Return a long value from an environment variable.
872  */
873 int
874 getenv_long(const char *name, long *data)
875 {
876 	quad_t tmp;
877 	int rval;
878 
879 	rval = getenv_quad(name, &tmp);
880 	if (rval)
881 		*data = (long) tmp;
882 	return (rval);
883 }
884 
885 /*
886  * Return an unsigned long value from an environment variable.
887  */
888 int
889 getenv_ulong(const char *name, unsigned long *data)
890 {
891 	quad_t tmp;
892 	int rval;
893 
894 	rval = getenv_quad(name, &tmp);
895 	if (rval)
896 		*data = (unsigned long) tmp;
897 	return (rval);
898 }
899 
900 /*
901  * Return a quad_t value from an environment variable.
902  */
903 int
904 getenv_quad(const char *name, quad_t *data)
905 {
906 	const char	*value;
907 	char		suffix, *vtp;
908 	quad_t		iv;
909 
910 	value = kenv_acquire(name);
911 	if (value == NULL) {
912 		goto error;
913 	}
914 	iv = strtoq(value, &vtp, 0);
915 	if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0')) {
916 		goto error;
917 	}
918 	suffix = vtp[0];
919 	kenv_release(value);
920 	switch (suffix) {
921 	case 't': case 'T':
922 		iv *= 1024;
923 		/* FALLTHROUGH */
924 	case 'g': case 'G':
925 		iv *= 1024;
926 		/* FALLTHROUGH */
927 	case 'm': case 'M':
928 		iv *= 1024;
929 		/* FALLTHROUGH */
930 	case 'k': case 'K':
931 		iv *= 1024;
932 	case '\0':
933 		break;
934 	default:
935 		return (0);
936 	}
937 	*data = iv;
938 	return (1);
939 error:
940 	kenv_release(value);
941 	return (0);
942 }
943 
944 /*
945  * Find the next entry after the one which (cp) falls within, return a
946  * pointer to its start or NULL if there are no more.
947  */
948 static char *
949 kernenv_next(char *cp)
950 {
951 
952 	if (cp != NULL) {
953 		while (*cp != 0)
954 			cp++;
955 		cp++;
956 		if (*cp == 0)
957 			cp = NULL;
958 	}
959 	return (cp);
960 }
961 
962 void
963 tunable_int_init(void *data)
964 {
965 	struct tunable_int *d = (struct tunable_int *)data;
966 
967 	TUNABLE_INT_FETCH(d->path, d->var);
968 }
969 
970 void
971 tunable_long_init(void *data)
972 {
973 	struct tunable_long *d = (struct tunable_long *)data;
974 
975 	TUNABLE_LONG_FETCH(d->path, d->var);
976 }
977 
978 void
979 tunable_ulong_init(void *data)
980 {
981 	struct tunable_ulong *d = (struct tunable_ulong *)data;
982 
983 	TUNABLE_ULONG_FETCH(d->path, d->var);
984 }
985 
986 void
987 tunable_int64_init(void *data)
988 {
989 	struct tunable_int64 *d = (struct tunable_int64 *)data;
990 
991 	TUNABLE_INT64_FETCH(d->path, d->var);
992 }
993 
994 void
995 tunable_uint64_init(void *data)
996 {
997 	struct tunable_uint64 *d = (struct tunable_uint64 *)data;
998 
999 	TUNABLE_UINT64_FETCH(d->path, d->var);
1000 }
1001 
1002 void
1003 tunable_quad_init(void *data)
1004 {
1005 	struct tunable_quad *d = (struct tunable_quad *)data;
1006 
1007 	TUNABLE_QUAD_FETCH(d->path, d->var);
1008 }
1009 
1010 void
1011 tunable_str_init(void *data)
1012 {
1013 	struct tunable_str *d = (struct tunable_str *)data;
1014 
1015 	TUNABLE_STR_FETCH(d->path, d->var, d->size);
1016 }
1017