1/*-
2 * Copyright (c) 1998 Michael Smith
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27/*
28 * The unified bootloader passes us a pointer to a preserved copy of
29 * bootstrap/kernel environment variables.  We convert them to a
30 * dynamic array of strings later when the VM subsystem is up.
31 *
32 * We make these available through the kenv(2) syscall for userland
33 * and through getenv()/freeenv() setenv() unsetenv() testenv() for
34 * the kernel.
35 */
36
37#include <sys/cdefs.h>
38__FBSDID("$FreeBSD$");
39
40#include <sys/types.h>
41#include <sys/param.h>
42#include <sys/proc.h>
43#include <sys/queue.h>
44#include <sys/lock.h>
45#include <sys/malloc.h>
46#include <sys/mutex.h>
47#include <sys/priv.h>
48#include <sys/kernel.h>
49#include <sys/systm.h>
50#include <sys/sysent.h>
51#include <sys/sysproto.h>
52#include <sys/libkern.h>
53#include <sys/kenv.h>
54
55#include <security/mac/mac_framework.h>
56
57static MALLOC_DEFINE(M_KENV, "kenv", "kernel environment");
58
59#define KENV_SIZE	512	/* Maximum number of environment strings */
60
61/* pointer to the static environment */
62char		*kern_envp;
63static int	env_len;
64static int	env_pos;
65static char	*kernenv_next(char *);
66
67/* dynamic environment variables */
68char		**kenvp;
69struct mtx	kenv_lock;
70
71/*
72 * No need to protect this with a mutex since SYSINITS are single threaded.
73 */
74int	dynamic_kenv = 0;
75
76#define KENV_CHECK	if (!dynamic_kenv) \
77			    panic("%s: called before SI_SUB_KMEM", __func__)
78
79int
80sys_kenv(td, uap)
81	struct thread *td;
82	struct kenv_args /* {
83		int what;
84		const char *name;
85		char *value;
86		int len;
87	} */ *uap;
88{
89	char *name, *value, *buffer = NULL;
90	size_t len, done, needed, buflen;
91	int error, i;
92
93	KASSERT(dynamic_kenv, ("kenv: dynamic_kenv = 0"));
94
95	error = 0;
96	if (uap->what == KENV_DUMP) {
97#ifdef MAC
98		error = mac_kenv_check_dump(td->td_ucred);
99		if (error)
100			return (error);
101#endif
102		done = needed = 0;
103		buflen = uap->len;
104		if (buflen > KENV_SIZE * (KENV_MNAMELEN + KENV_MVALLEN + 2))
105			buflen = KENV_SIZE * (KENV_MNAMELEN +
106			    KENV_MVALLEN + 2);
107		if (uap->len > 0 && uap->value != NULL)
108			buffer = malloc(buflen, M_TEMP, M_WAITOK|M_ZERO);
109		mtx_lock(&kenv_lock);
110		for (i = 0; kenvp[i] != NULL; i++) {
111			len = strlen(kenvp[i]) + 1;
112			needed += len;
113			len = min(len, buflen - done);
114			/*
115			 * If called with a NULL or insufficiently large
116			 * buffer, just keep computing the required size.
117			 */
118			if (uap->value != NULL && buffer != NULL && len > 0) {
119				bcopy(kenvp[i], buffer + done, len);
120				done += len;
121			}
122		}
123		mtx_unlock(&kenv_lock);
124		if (buffer != NULL) {
125			error = copyout(buffer, uap->value, done);
126			free(buffer, M_TEMP);
127		}
128		td->td_retval[0] = ((done == needed) ? 0 : needed);
129		return (error);
130	}
131
132	switch (uap->what) {
133	case KENV_SET:
134		error = priv_check(td, PRIV_KENV_SET);
135		if (error)
136			return (error);
137		break;
138
139	case KENV_UNSET:
140		error = priv_check(td, PRIV_KENV_UNSET);
141		if (error)
142			return (error);
143		break;
144	}
145
146	name = malloc(KENV_MNAMELEN + 1, M_TEMP, M_WAITOK);
147
148	error = copyinstr(uap->name, name, KENV_MNAMELEN + 1, NULL);
149	if (error)
150		goto done;
151
152	switch (uap->what) {
153	case KENV_GET:
154#ifdef MAC
155		error = mac_kenv_check_get(td->td_ucred, name);
156		if (error)
157			goto done;
158#endif
159		value = getenv(name);
160		if (value == NULL) {
161			error = ENOENT;
162			goto done;
163		}
164		len = strlen(value) + 1;
165		if (len > uap->len)
166			len = uap->len;
167		error = copyout(value, uap->value, len);
168		freeenv(value);
169		if (error)
170			goto done;
171		td->td_retval[0] = len;
172		break;
173	case KENV_SET:
174		len = uap->len;
175		if (len < 1) {
176			error = EINVAL;
177			goto done;
178		}
179		if (len > KENV_MVALLEN + 1)
180			len = KENV_MVALLEN + 1;
181		value = malloc(len, M_TEMP, M_WAITOK);
182		error = copyinstr(uap->value, value, len, NULL);
183		if (error) {
184			free(value, M_TEMP);
185			goto done;
186		}
187#ifdef MAC
188		error = mac_kenv_check_set(td->td_ucred, name, value);
189		if (error == 0)
190#endif
191			setenv(name, value);
192		free(value, M_TEMP);
193		break;
194	case KENV_UNSET:
195#ifdef MAC
196		error = mac_kenv_check_unset(td->td_ucred, name);
197		if (error)
198			goto done;
199#endif
200		error = unsetenv(name);
201		if (error)
202			error = ENOENT;
203		break;
204	default:
205		error = EINVAL;
206		break;
207	}
208done:
209	free(name, M_TEMP);
210	return (error);
211}
212
213void
214init_static_kenv(char *buf, size_t len)
215{
216	kern_envp = buf;
217	env_len = len;
218	env_pos = 0;
219}
220
221/*
222 * Setup the dynamic kernel environment.
223 */
224static void
225init_dynamic_kenv(void *data __unused)
226{
227	char *cp;
228	size_t len;
229	int i;
230
231	kenvp = malloc((KENV_SIZE + 1) * sizeof(char *), M_KENV,
232		M_WAITOK | M_ZERO);
233	i = 0;
234	if (kern_envp && *kern_envp != '\0') {
235		for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) {
236			len = strlen(cp) + 1;
237			if (len > KENV_MNAMELEN + 1 + KENV_MVALLEN + 1) {
238				printf(
239				"WARNING: too long kenv string, ignoring %s\n",
240				    cp);
241				continue;
242			}
243			if (i < KENV_SIZE) {
244				kenvp[i] = malloc(len, M_KENV, M_WAITOK);
245				strcpy(kenvp[i++], cp);
246			} else
247				printf(
248				"WARNING: too many kenv strings, ignoring %s\n",
249				    cp);
250		}
251	}
252	kenvp[i] = NULL;
253
254	mtx_init(&kenv_lock, "kernel environment", NULL, MTX_DEF);
255	dynamic_kenv = 1;
256}
257SYSINIT(kenv, SI_SUB_KMEM, SI_ORDER_ANY, init_dynamic_kenv, NULL);
258
259void
260freeenv(char *env)
261{
262
263	if (dynamic_kenv)
264		free(env, M_KENV);
265}
266
267/*
268 * Internal functions for string lookup.
269 */
270static char *
271_getenv_dynamic(const char *name, int *idx)
272{
273	char *cp;
274	int len, i;
275
276	mtx_assert(&kenv_lock, MA_OWNED);
277	len = strlen(name);
278	for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) {
279		if ((strncmp(cp, name, len) == 0) &&
280		    (cp[len] == '=')) {
281			if (idx != NULL)
282				*idx = i;
283			return (cp + len + 1);
284		}
285	}
286	return (NULL);
287}
288
289static char *
290_getenv_static(const char *name)
291{
292	char *cp, *ep;
293	int len;
294
295	for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) {
296		for (ep = cp; (*ep != '=') && (*ep != 0); ep++)
297			;
298		if (*ep != '=')
299			continue;
300		len = ep - cp;
301		ep++;
302		if (!strncmp(name, cp, len) && name[len] == 0)
303			return (ep);
304	}
305	return (NULL);
306}
307
308/*
309 * Look up an environment variable by name.
310 * Return a pointer to the string if found.
311 * The pointer has to be freed with freeenv()
312 * after use.
313 */
314char *
315getenv(const char *name)
316{
317	char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1];
318	char *ret;
319
320	if (dynamic_kenv) {
321		if (getenv_string(name, buf, sizeof(buf))) {
322			ret = strdup(buf, M_KENV);
323		} else {
324			ret = NULL;
325			WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
326			    "getenv");
327		}
328	} else
329		ret = _getenv_static(name);
330	return (ret);
331}
332
333/*
334 * Test if an environment variable is defined.
335 */
336int
337testenv(const char *name)
338{
339	char *cp;
340
341	if (dynamic_kenv) {
342		mtx_lock(&kenv_lock);
343		cp = _getenv_dynamic(name, NULL);
344		mtx_unlock(&kenv_lock);
345	} else
346		cp = _getenv_static(name);
347	if (cp != NULL)
348		return (1);
349	return (0);
350}
351
352static int
353setenv_static(const char *name, const char *value)
354{
355	int len;
356
357	if (env_pos >= env_len)
358		return (-1);
359
360	/* Check space for x=y and two nuls */
361	len = strlen(name) + strlen(value);
362	if (len + 3 < env_len - env_pos) {
363		len = sprintf(&kern_envp[env_pos], "%s=%s", name, value);
364		env_pos += len+1;
365		kern_envp[env_pos] = '\0';
366		return (0);
367	} else
368		return (-1);
369
370}
371
372/*
373 * Set an environment variable by name.
374 */
375int
376setenv(const char *name, const char *value)
377{
378	char *buf, *cp, *oldenv;
379	int namelen, vallen, i;
380
381	if (dynamic_kenv == 0 && env_len > 0)
382		return (setenv_static(name, value));
383
384	KENV_CHECK;
385
386	namelen = strlen(name) + 1;
387	if (namelen > KENV_MNAMELEN + 1)
388		return (-1);
389	vallen = strlen(value) + 1;
390	if (vallen > KENV_MVALLEN + 1)
391		return (-1);
392	buf = malloc(namelen + vallen, M_KENV, M_WAITOK);
393	sprintf(buf, "%s=%s", name, value);
394
395	mtx_lock(&kenv_lock);
396	cp = _getenv_dynamic(name, &i);
397	if (cp != NULL) {
398		oldenv = kenvp[i];
399		kenvp[i] = buf;
400		mtx_unlock(&kenv_lock);
401		free(oldenv, M_KENV);
402	} else {
403		/* We add the option if it wasn't found */
404		for (i = 0; (cp = kenvp[i]) != NULL; i++)
405			;
406
407		/* Bounds checking */
408		if (i < 0 || i >= KENV_SIZE) {
409			free(buf, M_KENV);
410			mtx_unlock(&kenv_lock);
411			return (-1);
412		}
413
414		kenvp[i] = buf;
415		kenvp[i + 1] = NULL;
416		mtx_unlock(&kenv_lock);
417	}
418	return (0);
419}
420
421/*
422 * Unset an environment variable string.
423 */
424int
425unsetenv(const char *name)
426{
427	char *cp, *oldenv;
428	int i, j;
429
430	KENV_CHECK;
431
432	mtx_lock(&kenv_lock);
433	cp = _getenv_dynamic(name, &i);
434	if (cp != NULL) {
435		oldenv = kenvp[i];
436		for (j = i + 1; kenvp[j] != NULL; j++)
437			kenvp[i++] = kenvp[j];
438		kenvp[i] = NULL;
439		mtx_unlock(&kenv_lock);
440		free(oldenv, M_KENV);
441		return (0);
442	}
443	mtx_unlock(&kenv_lock);
444	return (-1);
445}
446
447/*
448 * Return a string value from an environment variable.
449 */
450int
451getenv_string(const char *name, char *data, int size)
452{
453	char *cp;
454
455	if (dynamic_kenv) {
456		mtx_lock(&kenv_lock);
457		cp = _getenv_dynamic(name, NULL);
458		if (cp != NULL)
459			strlcpy(data, cp, size);
460		mtx_unlock(&kenv_lock);
461	} else {
462		cp = _getenv_static(name);
463		if (cp != NULL)
464			strlcpy(data, cp, size);
465	}
466	return (cp != NULL);
467}
468
469/*
470 * Return an integer value from an environment variable.
471 */
472int
473getenv_int(const char *name, int *data)
474{
475	quad_t tmp;
476	int rval;
477
478	rval = getenv_quad(name, &tmp);
479	if (rval)
480		*data = (int) tmp;
481	return (rval);
482}
483
484/*
485 * Return an unsigned integer value from an environment variable.
486 */
487int
488getenv_uint(const char *name, unsigned int *data)
489{
490	quad_t tmp;
491	int rval;
492
493	rval = getenv_quad(name, &tmp);
494	if (rval)
495		*data = (unsigned int) tmp;
496	return (rval);
497}
498
499/*
500 * Return a long value from an environment variable.
501 */
502int
503getenv_long(const char *name, long *data)
504{
505	quad_t tmp;
506	int rval;
507
508	rval = getenv_quad(name, &tmp);
509	if (rval)
510		*data = (long) tmp;
511	return (rval);
512}
513
514/*
515 * Return an unsigned long value from an environment variable.
516 */
517int
518getenv_ulong(const char *name, unsigned long *data)
519{
520	quad_t tmp;
521	int rval;
522
523	rval = getenv_quad(name, &tmp);
524	if (rval)
525		*data = (unsigned long) tmp;
526	return (rval);
527}
528
529/*
530 * Return a quad_t value from an environment variable.
531 */
532int
533getenv_quad(const char *name, quad_t *data)
534{
535	char	value[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1];
536	char	*vtp;
537	quad_t	iv;
538
539	if (!getenv_string(name, value, sizeof(value)))
540		return (0);
541	iv = strtoq(value, &vtp, 0);
542	if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0'))
543		return (0);
544	switch (vtp[0]) {
545	case 't': case 'T':
546		iv *= 1024;
547	case 'g': case 'G':
548		iv *= 1024;
549	case 'm': case 'M':
550		iv *= 1024;
551	case 'k': case 'K':
552		iv *= 1024;
553	case '\0':
554		break;
555	default:
556		return (0);
557	}
558	*data = iv;
559	return (1);
560}
561
562/*
563 * Find the next entry after the one which (cp) falls within, return a
564 * pointer to its start or NULL if there are no more.
565 */
566static char *
567kernenv_next(char *cp)
568{
569
570	if (cp != NULL) {
571		while (*cp != 0)
572			cp++;
573		cp++;
574		if (*cp == 0)
575			cp = NULL;
576	}
577	return (cp);
578}
579
580void
581tunable_int_init(void *data)
582{
583	struct tunable_int *d = (struct tunable_int *)data;
584
585	TUNABLE_INT_FETCH(d->path, d->var);
586}
587
588void
589tunable_long_init(void *data)
590{
591	struct tunable_long *d = (struct tunable_long *)data;
592
593	TUNABLE_LONG_FETCH(d->path, d->var);
594}
595
596void
597tunable_ulong_init(void *data)
598{
599	struct tunable_ulong *d = (struct tunable_ulong *)data;
600
601	TUNABLE_ULONG_FETCH(d->path, d->var);
602}
603
604void
605tunable_quad_init(void *data)
606{
607	struct tunable_quad *d = (struct tunable_quad *)data;
608
609	TUNABLE_QUAD_FETCH(d->path, d->var);
610}
611
612void
613tunable_str_init(void *data)
614{
615	struct tunable_str *d = (struct tunable_str *)data;
616
617	TUNABLE_STR_FETCH(d->path, d->var, d->size);
618}
619