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: releng/9.0/sys/kern/kern_environment.c 225617 2011-09-16 13:58:51Z kmacy $");
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
57 static 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 */
62 char *kern_envp;
63 static int env_len;
64 static int env_pos;
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 sys_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, M_TEMP, M_WAITOK);
147
148 error = copyinstr(uap->name, name, KENV_MNAMELEN, 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)
180 len = KENV_MVALLEN;
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 }
208 done:
209 free(name, M_TEMP);
210 return (error);
211 }
212
213 void
214 init_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 */
224 static void
225 init_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 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) {
235 len = strlen(cp) + 1;
236 if (len > KENV_MNAMELEN + 1 + KENV_MVALLEN + 1) {
237 printf("WARNING: too long kenv string, ignoring %s\n",
238 cp);
239 continue;
240 }
241 if (i < KENV_SIZE) {
242 kenvp[i] = malloc(len, M_KENV, M_WAITOK);
243 strcpy(kenvp[i++], cp);
244 } else
245 printf(
246 "WARNING: too many kenv strings, ignoring %s\n",
247 cp);
248 }
249 kenvp[i] = NULL;
250
251 mtx_init(&kenv_lock, "kernel environment", NULL, MTX_DEF);
252 dynamic_kenv = 1;
253 }
254 SYSINIT(kenv, SI_SUB_KMEM, SI_ORDER_ANY, init_dynamic_kenv, NULL);
255
256 void
257 freeenv(char *env)
258 {
259
260 if (dynamic_kenv)
261 free(env, M_KENV);
262 }
263
264 /*
265 * Internal functions for string lookup.
266 */
267 static char *
268 _getenv_dynamic(const char *name, int *idx)
269 {
270 char *cp;
271 int len, i;
272
273 mtx_assert(&kenv_lock, MA_OWNED);
274 len = strlen(name);
275 for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) {
276 if ((strncmp(cp, name, len) == 0) &&
277 (cp[len] == '=')) {
278 if (idx != NULL)
279 *idx = i;
280 return (cp + len + 1);
281 }
282 }
283 return (NULL);
284 }
285
286 static char *
287 _getenv_static(const char *name)
288 {
289 char *cp, *ep;
290 int len;
291
292 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) {
293 for (ep = cp; (*ep != '=') && (*ep != 0); ep++)
294 ;
295 if (*ep != '=')
296 continue;
297 len = ep - cp;
298 ep++;
299 if (!strncmp(name, cp, len) && name[len] == 0)
300 return (ep);
301 }
302 return (NULL);
303 }
304
305 /*
306 * Look up an environment variable by name.
307 * Return a pointer to the string if found.
308 * The pointer has to be freed with freeenv()
309 * after use.
310 */
311 char *
312 getenv(const char *name)
313 {
314 char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1];
315 char *ret, *cp;
316 int len;
317
318 if (dynamic_kenv) {
319 mtx_lock(&kenv_lock);
320 cp = _getenv_dynamic(name, NULL);
321 if (cp != NULL) {
322 strcpy(buf, cp);
323 mtx_unlock(&kenv_lock);
324 len = strlen(buf) + 1;
325 ret = malloc(len, M_KENV, M_WAITOK);
326 strcpy(ret, buf);
327 } else {
328 mtx_unlock(&kenv_lock);
329 ret = NULL;
330 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
331 "getenv");
332 }
333 } else
334 ret = _getenv_static(name);
335 return (ret);
336 }
337
338 /*
339 * Test if an environment variable is defined.
340 */
341 int
342 testenv(const char *name)
343 {
344 char *cp;
345
346 if (dynamic_kenv) {
347 mtx_lock(&kenv_lock);
348 cp = _getenv_dynamic(name, NULL);
349 mtx_unlock(&kenv_lock);
350 } else
351 cp = _getenv_static(name);
352 if (cp != NULL)
353 return (1);
354 return (0);
355 }
356
357 static int
358 setenv_static(const char *name, const char *value)
359 {
360 int len;
361
362 if (env_pos >= env_len)
363 return (-1);
364
365 /* Check space for x=y and two nuls */
366 len = strlen(name) + strlen(value);
367 if (len + 3 < env_len - env_pos) {
368 len = sprintf(&kern_envp[env_pos], "%s=%s", name, value);
369 env_pos += len+1;
370 kern_envp[env_pos] = '\0';
371 return (0);
372 } else
373 return (-1);
374
375 }
376
377 /*
378 * Set an environment variable by name.
379 */
380 int
381 setenv(const char *name, const char *value)
382 {
383 char *buf, *cp, *oldenv;
384 int namelen, vallen, i;
385
386 if (dynamic_kenv == 0 && env_len > 0)
387 return (setenv_static(name, value));
388
389 KENV_CHECK;
390
391 namelen = strlen(name) + 1;
392 if (namelen > KENV_MNAMELEN)
393 return (-1);
394 vallen = strlen(value) + 1;
395 if (vallen > KENV_MVALLEN)
396 return (-1);
397 buf = malloc(namelen + vallen, M_KENV, M_WAITOK);
398 sprintf(buf, "%s=%s", name, value);
399
400 mtx_lock(&kenv_lock);
401 cp = _getenv_dynamic(name, &i);
402 if (cp != NULL) {
403 oldenv = kenvp[i];
404 kenvp[i] = buf;
405 mtx_unlock(&kenv_lock);
406 free(oldenv, M_KENV);
407 } else {
408 /* We add the option if it wasn't found */
409 for (i = 0; (cp = kenvp[i]) != NULL; i++)
410 ;
411
412 /* Bounds checking */
413 if (i < 0 || i >= KENV_SIZE) {
414 free(buf, M_KENV);
415 mtx_unlock(&kenv_lock);
416 return (-1);
417 }
418
419 kenvp[i] = buf;
420 kenvp[i + 1] = NULL;
421 mtx_unlock(&kenv_lock);
422 }
423 return (0);
424 }
425
426 /*
427 * Unset an environment variable string.
428 */
429 int
430 unsetenv(const char *name)
431 {
432 char *cp, *oldenv;
433 int i, j;
434
435 KENV_CHECK;
436
437 mtx_lock(&kenv_lock);
438 cp = _getenv_dynamic(name, &i);
439 if (cp != NULL) {
440 oldenv = kenvp[i];
441 for (j = i + 1; kenvp[j] != NULL; j++)
442 kenvp[i++] = kenvp[j];
443 kenvp[i] = NULL;
444 mtx_unlock(&kenv_lock);
445 free(oldenv, M_KENV);
446 return (0);
447 }
448 mtx_unlock(&kenv_lock);
449 return (-1);
450 }
451
452 /*
453 * Return a string value from an environment variable.
454 */
455 int
456 getenv_string(const char *name, char *data, int size)
457 {
458 char *tmp;
459
460 tmp = getenv(name);
461 if (tmp != NULL) {
462 strlcpy(data, tmp, size);
463 freeenv(tmp);
464 return (1);
465 } else
466 return (0);
467 }
468
469 /*
470 * Return an integer value from an environment variable.
471 */
472 int
473 getenv_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 */
487 int
488 getenv_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 */
502 int
503 getenv_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 */
517 int
518 getenv_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 */
532 int
533 getenv_quad(const char *name, quad_t *data)
534 {
535 char *value;
536 char *vtp;
537 quad_t iv;
538
539 value = getenv(name);
540 if (value == NULL)
541 return (0);
542 iv = strtoq(value, &vtp, 0);
543 if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0')) {
544 freeenv(value);
545 return (0);
546 }
547 switch (vtp[0]) {
548 case 't': case 'T':
549 iv *= 1024;
550 case 'g': case 'G':
551 iv *= 1024;
552 case 'm': case 'M':
553 iv *= 1024;
554 case 'k': case 'K':
555 iv *= 1024;
556 case '\0':
557 break;
558 default:
559 freeenv(value);
560 return (0);
561 }
562 *data = iv;
563 freeenv(value);
564 return (1);
565 }
566
567 /*
568 * Find the next entry after the one which (cp) falls within, return a
569 * pointer to its start or NULL if there are no more.
570 */
571 static char *
572 kernenv_next(char *cp)
573 {
574
575 if (cp != NULL) {
576 while (*cp != 0)
577 cp++;
578 cp++;
579 if (*cp == 0)
580 cp = NULL;
581 }
582 return (cp);
583 }
584
585 void
586 tunable_int_init(void *data)
587 {
588 struct tunable_int *d = (struct tunable_int *)data;
589
590 TUNABLE_INT_FETCH(d->path, d->var);
591 }
592
593 void
594 tunable_long_init(void *data)
595 {
596 struct tunable_long *d = (struct tunable_long *)data;
597
598 TUNABLE_LONG_FETCH(d->path, d->var);
599 }
600
601 void
602 tunable_ulong_init(void *data)
603 {
604 struct tunable_ulong *d = (struct tunable_ulong *)data;
605
606 TUNABLE_ULONG_FETCH(d->path, d->var);
607 }
608
609 void
610 tunable_quad_init(void *data)
611 {
612 struct tunable_quad *d = (struct tunable_quad *)data;
613
614 TUNABLE_QUAD_FETCH(d->path, d->var);
615 }
616
617 void
618 tunable_str_init(void *data)
619 {
620 struct tunable_str *d = (struct tunable_str *)data;
621
622 TUNABLE_STR_FETCH(d->path, d->var, d->size);
623 }
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