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/10.0/sys/kern/kern_environment.c 249570 2013-04-16 22:09:08Z imp $");
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 + 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 }
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 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 }
257 SYSINIT(kenv, SI_SUB_KMEM, SI_ORDER_ANY, init_dynamic_kenv, NULL);
258
259 void
260 freeenv(char *env)
261 {
262
263 if (dynamic_kenv)
264 free(env, M_KENV);
265 }
266
267 /*
268 * Internal functions for string lookup.
269 */
270 static 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
289 static 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 */
314 char *
315 getenv(const char *name)
316 {
317 char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1];
318 char *ret, *cp;
319 int len;
320
321 if (dynamic_kenv) {
322 mtx_lock(&kenv_lock);
323 cp = _getenv_dynamic(name, NULL);
324 if (cp != NULL) {
325 strcpy(buf, cp);
326 mtx_unlock(&kenv_lock);
327 len = strlen(buf) + 1;
328 ret = malloc(len, M_KENV, M_WAITOK);
329 strcpy(ret, buf);
330 } else {
331 mtx_unlock(&kenv_lock);
332 ret = NULL;
333 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
334 "getenv");
335 }
336 } else
337 ret = _getenv_static(name);
338 return (ret);
339 }
340
341 /*
342 * Test if an environment variable is defined.
343 */
344 int
345 testenv(const char *name)
346 {
347 char *cp;
348
349 if (dynamic_kenv) {
350 mtx_lock(&kenv_lock);
351 cp = _getenv_dynamic(name, NULL);
352 mtx_unlock(&kenv_lock);
353 } else
354 cp = _getenv_static(name);
355 if (cp != NULL)
356 return (1);
357 return (0);
358 }
359
360 static int
361 setenv_static(const char *name, const char *value)
362 {
363 int len;
364
365 if (env_pos >= env_len)
366 return (-1);
367
368 /* Check space for x=y and two nuls */
369 len = strlen(name) + strlen(value);
370 if (len + 3 < env_len - env_pos) {
371 len = sprintf(&kern_envp[env_pos], "%s=%s", name, value);
372 env_pos += len+1;
373 kern_envp[env_pos] = '\0';
374 return (0);
375 } else
376 return (-1);
377
378 }
379
380 /*
381 * Set an environment variable by name.
382 */
383 int
384 setenv(const char *name, const char *value)
385 {
386 char *buf, *cp, *oldenv;
387 int namelen, vallen, i;
388
389 if (dynamic_kenv == 0 && env_len > 0)
390 return (setenv_static(name, value));
391
392 KENV_CHECK;
393
394 namelen = strlen(name) + 1;
395 if (namelen > KENV_MNAMELEN + 1)
396 return (-1);
397 vallen = strlen(value) + 1;
398 if (vallen > KENV_MVALLEN + 1)
399 return (-1);
400 buf = malloc(namelen + vallen, M_KENV, M_WAITOK);
401 sprintf(buf, "%s=%s", name, value);
402
403 mtx_lock(&kenv_lock);
404 cp = _getenv_dynamic(name, &i);
405 if (cp != NULL) {
406 oldenv = kenvp[i];
407 kenvp[i] = buf;
408 mtx_unlock(&kenv_lock);
409 free(oldenv, M_KENV);
410 } else {
411 /* We add the option if it wasn't found */
412 for (i = 0; (cp = kenvp[i]) != NULL; i++)
413 ;
414
415 /* Bounds checking */
416 if (i < 0 || i >= KENV_SIZE) {
417 free(buf, M_KENV);
418 mtx_unlock(&kenv_lock);
419 return (-1);
420 }
421
422 kenvp[i] = buf;
423 kenvp[i + 1] = NULL;
424 mtx_unlock(&kenv_lock);
425 }
426 return (0);
427 }
428
429 /*
430 * Unset an environment variable string.
431 */
432 int
433 unsetenv(const char *name)
434 {
435 char *cp, *oldenv;
436 int i, j;
437
438 KENV_CHECK;
439
440 mtx_lock(&kenv_lock);
441 cp = _getenv_dynamic(name, &i);
442 if (cp != NULL) {
443 oldenv = kenvp[i];
444 for (j = i + 1; kenvp[j] != NULL; j++)
445 kenvp[i++] = kenvp[j];
446 kenvp[i] = NULL;
447 mtx_unlock(&kenv_lock);
448 free(oldenv, M_KENV);
449 return (0);
450 }
451 mtx_unlock(&kenv_lock);
452 return (-1);
453 }
454
455 /*
456 * Return a string value from an environment variable.
457 */
458 int
459 getenv_string(const char *name, char *data, int size)
460 {
461 char *tmp;
462
463 tmp = getenv(name);
464 if (tmp != NULL) {
465 strlcpy(data, tmp, size);
466 freeenv(tmp);
467 return (1);
468 } else
469 return (0);
470 }
471
472 /*
473 * Return an integer value from an environment variable.
474 */
475 int
476 getenv_int(const char *name, int *data)
477 {
478 quad_t tmp;
479 int rval;
480
481 rval = getenv_quad(name, &tmp);
482 if (rval)
483 *data = (int) tmp;
484 return (rval);
485 }
486
487 /*
488 * Return an unsigned integer value from an environment variable.
489 */
490 int
491 getenv_uint(const char *name, unsigned int *data)
492 {
493 quad_t tmp;
494 int rval;
495
496 rval = getenv_quad(name, &tmp);
497 if (rval)
498 *data = (unsigned int) tmp;
499 return (rval);
500 }
501
502 /*
503 * Return a long value from an environment variable.
504 */
505 int
506 getenv_long(const char *name, long *data)
507 {
508 quad_t tmp;
509 int rval;
510
511 rval = getenv_quad(name, &tmp);
512 if (rval)
513 *data = (long) tmp;
514 return (rval);
515 }
516
517 /*
518 * Return an unsigned long value from an environment variable.
519 */
520 int
521 getenv_ulong(const char *name, unsigned long *data)
522 {
523 quad_t tmp;
524 int rval;
525
526 rval = getenv_quad(name, &tmp);
527 if (rval)
528 *data = (unsigned long) tmp;
529 return (rval);
530 }
531
532 /*
533 * Return a quad_t value from an environment variable.
534 */
535 int
536 getenv_quad(const char *name, quad_t *data)
537 {
538 char *value;
539 char *vtp;
540 quad_t iv;
541
542 value = getenv(name);
543 if (value == NULL)
544 return (0);
545 iv = strtoq(value, &vtp, 0);
546 if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0')) {
547 freeenv(value);
548 return (0);
549 }
550 switch (vtp[0]) {
551 case 't': case 'T':
552 iv *= 1024;
553 case 'g': case 'G':
554 iv *= 1024;
555 case 'm': case 'M':
556 iv *= 1024;
557 case 'k': case 'K':
558 iv *= 1024;
559 case '\0':
560 break;
561 default:
562 freeenv(value);
563 return (0);
564 }
565 *data = iv;
566 freeenv(value);
567 return (1);
568 }
569
570 /*
571 * Find the next entry after the one which (cp) falls within, return a
572 * pointer to its start or NULL if there are no more.
573 */
574 static char *
575 kernenv_next(char *cp)
576 {
577
578 if (cp != NULL) {
579 while (*cp != 0)
580 cp++;
581 cp++;
582 if (*cp == 0)
583 cp = NULL;
584 }
585 return (cp);
586 }
587
588 void
589 tunable_int_init(void *data)
590 {
591 struct tunable_int *d = (struct tunable_int *)data;
592
593 TUNABLE_INT_FETCH(d->path, d->var);
594 }
595
596 void
597 tunable_long_init(void *data)
598 {
599 struct tunable_long *d = (struct tunable_long *)data;
600
601 TUNABLE_LONG_FETCH(d->path, d->var);
602 }
603
604 void
605 tunable_ulong_init(void *data)
606 {
607 struct tunable_ulong *d = (struct tunable_ulong *)data;
608
609 TUNABLE_ULONG_FETCH(d->path, d->var);
610 }
611
612 void
613 tunable_quad_init(void *data)
614 {
615 struct tunable_quad *d = (struct tunable_quad *)data;
616
617 TUNABLE_QUAD_FETCH(d->path, d->var);
618 }
619
620 void
621 tunable_str_init(void *data)
622 {
623 struct tunable_str *d = (struct tunable_str *)data;
624
625 TUNABLE_STR_FETCH(d->path, d->var, d->size);
626 }
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