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: src/sys/kern/kern_environment.c,v 1.50 2008/07/21 15:05:25 pjd Exp $");
39
40 #include "opt_mac.h"
41
42 #include <sys/types.h>
43 #include <sys/param.h>
44 #include <sys/proc.h>
45 #include <sys/queue.h>
46 #include <sys/lock.h>
47 #include <sys/malloc.h>
48 #include <sys/mutex.h>
49 #include <sys/priv.h>
50 #include <sys/kernel.h>
51 #include <sys/systm.h>
52 #include <sys/sysent.h>
53 #include <sys/sysproto.h>
54 #include <sys/libkern.h>
55 #include <sys/kenv.h>
56
57 #include <security/mac/mac_framework.h>
58
59 static MALLOC_DEFINE(M_KENV, "kenv", "kernel environment");
60
61 #define KENV_SIZE 512 /* Maximum number of environment strings */
62
63 /* pointer to the static environment */
64 char *kern_envp;
65 static char *kernenv_next(char *);
66
67 /* dynamic environment variables */
68 char **kenvp;
69 struct mtx kenv_lock;
70
71 /*
72 * No need to protect this with a mutex since SYSINITS are single threaded.
73 */
74 int dynamic_kenv = 0;
75
76 #define KENV_CHECK if (!dynamic_kenv) \
77 panic("%s: called before SI_SUB_KMEM", __func__)
78
79 int
80 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;
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 if (uap->len > 0 && uap->value != NULL)
104 buffer = malloc(uap->len, M_TEMP, M_WAITOK|M_ZERO);
105 mtx_lock(&kenv_lock);
106 for (i = 0; kenvp[i] != NULL; i++) {
107 len = strlen(kenvp[i]) + 1;
108 needed += len;
109 len = min(len, uap->len - done);
110 /*
111 * If called with a NULL or insufficiently large
112 * buffer, just keep computing the required size.
113 */
114 if (uap->value != NULL && buffer != NULL && len > 0) {
115 bcopy(kenvp[i], buffer + done, len);
116 done += len;
117 }
118 }
119 mtx_unlock(&kenv_lock);
120 if (buffer != NULL) {
121 error = copyout(buffer, uap->value, done);
122 free(buffer, M_TEMP);
123 }
124 td->td_retval[0] = ((done == needed) ? 0 : needed);
125 return (error);
126 }
127
128 switch (uap->what) {
129 case KENV_SET:
130 error = priv_check(td, PRIV_KENV_SET);
131 if (error)
132 return (error);
133 break;
134
135 case KENV_UNSET:
136 error = priv_check(td, PRIV_KENV_UNSET);
137 if (error)
138 return (error);
139 break;
140 }
141
142 name = malloc(KENV_MNAMELEN, M_TEMP, M_WAITOK);
143
144 error = copyinstr(uap->name, name, KENV_MNAMELEN, NULL);
145 if (error)
146 goto done;
147
148 switch (uap->what) {
149 case KENV_GET:
150 #ifdef MAC
151 error = mac_kenv_check_get(td->td_ucred, name);
152 if (error)
153 goto done;
154 #endif
155 value = getenv(name);
156 if (value == NULL) {
157 error = ENOENT;
158 goto done;
159 }
160 len = strlen(value) + 1;
161 if (len > uap->len)
162 len = uap->len;
163 error = copyout(value, uap->value, len);
164 freeenv(value);
165 if (error)
166 goto done;
167 td->td_retval[0] = len;
168 break;
169 case KENV_SET:
170 len = uap->len;
171 if (len < 1) {
172 error = EINVAL;
173 goto done;
174 }
175 if (len > KENV_MVALLEN)
176 len = KENV_MVALLEN;
177 value = malloc(len, M_TEMP, M_WAITOK);
178 error = copyinstr(uap->value, value, len, NULL);
179 if (error) {
180 free(value, M_TEMP);
181 goto done;
182 }
183 #ifdef MAC
184 error = mac_kenv_check_set(td->td_ucred, name, value);
185 if (error == 0)
186 #endif
187 setenv(name, value);
188 free(value, M_TEMP);
189 break;
190 case KENV_UNSET:
191 #ifdef MAC
192 error = mac_kenv_check_unset(td->td_ucred, name);
193 if (error)
194 goto done;
195 #endif
196 error = unsetenv(name);
197 if (error)
198 error = ENOENT;
199 break;
200 default:
201 error = EINVAL;
202 break;
203 }
204 done:
205 free(name, M_TEMP);
206 return (error);
207 }
208
209 /*
210 * Setup the dynamic kernel environment.
211 */
212 static void
213 init_dynamic_kenv(void *data __unused)
214 {
215 char *cp;
216 int len, i;
217
218 kenvp = malloc((KENV_SIZE + 1) * sizeof(char *), M_KENV,
219 M_WAITOK | M_ZERO);
220 i = 0;
221 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) {
222 len = strlen(cp) + 1;
223 if (i < KENV_SIZE) {
224 kenvp[i] = malloc(len, M_KENV, M_WAITOK);
225 strcpy(kenvp[i++], cp);
226 } else
227 printf(
228 "WARNING: too many kenv strings, ignoring %s\n",
229 cp);
230 }
231 kenvp[i] = NULL;
232
233 mtx_init(&kenv_lock, "kernel environment", NULL, MTX_DEF);
234 dynamic_kenv = 1;
235 }
236 SYSINIT(kenv, SI_SUB_KMEM, SI_ORDER_ANY, init_dynamic_kenv, NULL);
237
238 void
239 freeenv(char *env)
240 {
241
242 if (dynamic_kenv)
243 free(env, M_KENV);
244 }
245
246 /*
247 * Internal functions for string lookup.
248 */
249 static char *
250 _getenv_dynamic(const char *name, int *idx)
251 {
252 char *cp;
253 int len, i;
254
255 mtx_assert(&kenv_lock, MA_OWNED);
256 len = strlen(name);
257 for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) {
258 if ((strncmp(cp, name, len) == 0) &&
259 (cp[len] == '=')) {
260 if (idx != NULL)
261 *idx = i;
262 return (cp + len + 1);
263 }
264 }
265 return (NULL);
266 }
267
268 static char *
269 _getenv_static(const char *name)
270 {
271 char *cp, *ep;
272 int len;
273
274 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) {
275 for (ep = cp; (*ep != '=') && (*ep != 0); ep++)
276 ;
277 if (*ep != '=')
278 continue;
279 len = ep - cp;
280 ep++;
281 if (!strncmp(name, cp, len) && name[len] == 0)
282 return (ep);
283 }
284 return (NULL);
285 }
286
287 /*
288 * Look up an environment variable by name.
289 * Return a pointer to the string if found.
290 * The pointer has to be freed with freeenv()
291 * after use.
292 */
293 char *
294 getenv(const char *name)
295 {
296 char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1];
297 char *ret, *cp;
298 int len;
299
300 if (dynamic_kenv) {
301 mtx_lock(&kenv_lock);
302 cp = _getenv_dynamic(name, NULL);
303 if (cp != NULL) {
304 strcpy(buf, cp);
305 mtx_unlock(&kenv_lock);
306 len = strlen(buf) + 1;
307 ret = malloc(len, M_KENV, M_WAITOK);
308 strcpy(ret, buf);
309 } else {
310 mtx_unlock(&kenv_lock);
311 ret = NULL;
312 }
313 } else
314 ret = _getenv_static(name);
315 return (ret);
316 }
317
318 /*
319 * Test if an environment variable is defined.
320 */
321 int
322 testenv(const char *name)
323 {
324 char *cp;
325
326 if (dynamic_kenv) {
327 mtx_lock(&kenv_lock);
328 cp = _getenv_dynamic(name, NULL);
329 mtx_unlock(&kenv_lock);
330 } else
331 cp = _getenv_static(name);
332 if (cp != NULL)
333 return (1);
334 return (0);
335 }
336
337 /*
338 * Set an environment variable by name.
339 */
340 int
341 setenv(const char *name, const char *value)
342 {
343 char *buf, *cp, *oldenv;
344 int namelen, vallen, i;
345
346 KENV_CHECK;
347
348 namelen = strlen(name) + 1;
349 if (namelen > KENV_MNAMELEN)
350 return (-1);
351 vallen = strlen(value) + 1;
352 if (vallen > KENV_MVALLEN)
353 return (-1);
354 buf = malloc(namelen + vallen, M_KENV, M_WAITOK);
355 sprintf(buf, "%s=%s", name, value);
356
357 mtx_lock(&kenv_lock);
358 cp = _getenv_dynamic(name, &i);
359 if (cp != NULL) {
360 oldenv = kenvp[i];
361 kenvp[i] = buf;
362 mtx_unlock(&kenv_lock);
363 free(oldenv, M_KENV);
364 } else {
365 /* We add the option if it wasn't found */
366 for (i = 0; (cp = kenvp[i]) != NULL; i++)
367 ;
368
369 /* Bounds checking */
370 if (i < 0 || i >= KENV_SIZE) {
371 free(buf, M_KENV);
372 mtx_unlock(&kenv_lock);
373 return (-1);
374 }
375
376 kenvp[i] = buf;
377 kenvp[i + 1] = NULL;
378 mtx_unlock(&kenv_lock);
379 }
380 return (0);
381 }
382
383 /*
384 * Unset an environment variable string.
385 */
386 int
387 unsetenv(const char *name)
388 {
389 char *cp, *oldenv;
390 int i, j;
391
392 KENV_CHECK;
393
394 mtx_lock(&kenv_lock);
395 cp = _getenv_dynamic(name, &i);
396 if (cp != NULL) {
397 oldenv = kenvp[i];
398 for (j = i + 1; kenvp[j] != NULL; j++)
399 kenvp[i++] = kenvp[j];
400 kenvp[i] = NULL;
401 mtx_unlock(&kenv_lock);
402 free(oldenv, M_KENV);
403 return (0);
404 }
405 mtx_unlock(&kenv_lock);
406 return (-1);
407 }
408
409 /*
410 * Return a string value from an environment variable.
411 */
412 int
413 getenv_string(const char *name, char *data, int size)
414 {
415 char *tmp;
416
417 tmp = getenv(name);
418 if (tmp != NULL) {
419 strlcpy(data, tmp, size);
420 freeenv(tmp);
421 return (1);
422 } else
423 return (0);
424 }
425
426 /*
427 * Return an integer value from an environment variable.
428 */
429 int
430 getenv_int(const char *name, int *data)
431 {
432 quad_t tmp;
433 int rval;
434
435 rval = getenv_quad(name, &tmp);
436 if (rval)
437 *data = (int) tmp;
438 return (rval);
439 }
440
441 /*
442 * Return an unsigned integer value from an environment variable.
443 */
444 int
445 getenv_uint(const char *name, unsigned int *data)
446 {
447 quad_t tmp;
448 int rval;
449
450 rval = getenv_quad(name, &tmp);
451 if (rval)
452 *data = (unsigned int) tmp;
453 return (rval);
454 }
455
456 /*
457 * Return a long value from an environment variable.
458 */
459 int
460 getenv_long(const char *name, long *data)
461 {
462 quad_t tmp;
463 int rval;
464
465 rval = getenv_quad(name, &tmp);
466 if (rval)
467 *data = (long) tmp;
468 return (rval);
469 }
470
471 /*
472 * Return an unsigned long value from an environment variable.
473 */
474 int
475 getenv_ulong(const char *name, unsigned long *data)
476 {
477 quad_t tmp;
478 int rval;
479
480 rval = getenv_quad(name, &tmp);
481 if (rval)
482 *data = (unsigned long) tmp;
483 return (rval);
484 }
485
486 /*
487 * Return a quad_t value from an environment variable.
488 */
489 int
490 getenv_quad(const char *name, quad_t *data)
491 {
492 char *value;
493 char *vtp;
494 quad_t iv;
495
496 value = getenv(name);
497 if (value == NULL)
498 return (0);
499 iv = strtoq(value, &vtp, 0);
500 if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0')) {
501 freeenv(value);
502 return (0);
503 }
504 switch (vtp[0]) {
505 case 't': case 'T':
506 iv *= 1024;
507 case 'g': case 'G':
508 iv *= 1024;
509 case 'm': case 'M':
510 iv *= 1024;
511 case 'k': case 'K':
512 iv *= 1024;
513 case '\0':
514 break;
515 default:
516 freeenv(value);
517 return (0);
518 }
519 *data = iv;
520 freeenv(value);
521 return (1);
522 }
523
524 /*
525 * Find the next entry after the one which (cp) falls within, return a
526 * pointer to its start or NULL if there are no more.
527 */
528 static char *
529 kernenv_next(char *cp)
530 {
531
532 if (cp != NULL) {
533 while (*cp != 0)
534 cp++;
535 cp++;
536 if (*cp == 0)
537 cp = NULL;
538 }
539 return (cp);
540 }
541
542 void
543 tunable_int_init(void *data)
544 {
545 struct tunable_int *d = (struct tunable_int *)data;
546
547 TUNABLE_INT_FETCH(d->path, d->var);
548 }
549
550 void
551 tunable_long_init(void *data)
552 {
553 struct tunable_long *d = (struct tunable_long *)data;
554
555 TUNABLE_LONG_FETCH(d->path, d->var);
556 }
557
558 void
559 tunable_ulong_init(void *data)
560 {
561 struct tunable_ulong *d = (struct tunable_ulong *)data;
562
563 TUNABLE_ULONG_FETCH(d->path, d->var);
564 }
565
566 void
567 tunable_quad_init(void *data)
568 {
569 struct tunable_quad *d = (struct tunable_quad *)data;
570
571 TUNABLE_QUAD_FETCH(d->path, d->var);
572 }
573
574 void
575 tunable_str_init(void *data)
576 {
577 struct tunable_str *d = (struct tunable_str *)data;
578
579 TUNABLE_STR_FETCH(d->path, d->var, d->size);
580 }
581
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