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 "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, 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_check_kenv_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_check_kenv_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_check_kenv_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_check_kenv_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 /*
214 * Setup the dynamic kernel environment.
215 */
216 static void
217 init_dynamic_kenv(void *data __unused)
218 {
219 char *cp;
220 size_t len;
221 int i;
222
223 kenvp = malloc((KENV_SIZE + 1) * sizeof(char *), M_KENV,
224 M_WAITOK | M_ZERO);
225 i = 0;
226 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) {
227 len = strlen(cp) + 1;
228 if (len > KENV_MNAMELEN + 1 + KENV_MVALLEN + 1) {
229 printf("WARNING: too long kenv string, ignoring %s\n",
230 cp);
231 continue;
232 }
233 if (i < KENV_SIZE) {
234 kenvp[i] = malloc(len, M_KENV, M_WAITOK);
235 strcpy(kenvp[i++], cp);
236 } else
237 printf(
238 "WARNING: too many kenv strings, ignoring %s\n",
239 cp);
240 }
241 kenvp[i] = NULL;
242
243 mtx_init(&kenv_lock, "kernel environment", NULL, MTX_DEF);
244 dynamic_kenv = 1;
245 }
246 SYSINIT(kenv, SI_SUB_KMEM, SI_ORDER_ANY, init_dynamic_kenv, NULL);
247
248 void
249 freeenv(char *env)
250 {
251
252 if (dynamic_kenv)
253 free(env, M_KENV);
254 }
255
256 /*
257 * Internal functions for string lookup.
258 */
259 static char *
260 _getenv_dynamic(const char *name, int *idx)
261 {
262 char *cp;
263 int len, i;
264
265 mtx_assert(&kenv_lock, MA_OWNED);
266 len = strlen(name);
267 for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) {
268 if ((strncmp(cp, name, len) == 0) &&
269 (cp[len] == '=')) {
270 if (idx != NULL)
271 *idx = i;
272 return (cp + len + 1);
273 }
274 }
275 return (NULL);
276 }
277
278 static char *
279 _getenv_static(const char *name)
280 {
281 char *cp, *ep;
282 int len;
283
284 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) {
285 for (ep = cp; (*ep != '=') && (*ep != 0); ep++)
286 ;
287 if (*ep != '=')
288 continue;
289 len = ep - cp;
290 ep++;
291 if (!strncmp(name, cp, len) && name[len] == 0)
292 return (ep);
293 }
294 return (NULL);
295 }
296
297 /*
298 * Look up an environment variable by name.
299 * Return a pointer to the string if found.
300 * The pointer has to be freed with freeenv()
301 * after use.
302 */
303 char *
304 getenv(const char *name)
305 {
306 char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1];
307 char *ret, *cp;
308 int len;
309
310 if (dynamic_kenv) {
311 mtx_lock(&kenv_lock);
312 cp = _getenv_dynamic(name, NULL);
313 if (cp != NULL) {
314 strcpy(buf, cp);
315 mtx_unlock(&kenv_lock);
316 len = strlen(buf) + 1;
317 ret = malloc(len, M_KENV, M_WAITOK);
318 strcpy(ret, buf);
319 } else {
320 mtx_unlock(&kenv_lock);
321 ret = NULL;
322 }
323 } else
324 ret = _getenv_static(name);
325 return (ret);
326 }
327
328 /*
329 * Test if an environment variable is defined.
330 */
331 int
332 testenv(const char *name)
333 {
334 char *cp;
335
336 if (dynamic_kenv) {
337 mtx_lock(&kenv_lock);
338 cp = _getenv_dynamic(name, NULL);
339 mtx_unlock(&kenv_lock);
340 } else
341 cp = _getenv_static(name);
342 if (cp != NULL)
343 return (1);
344 return (0);
345 }
346
347 /*
348 * Set an environment variable by name.
349 */
350 int
351 setenv(const char *name, const char *value)
352 {
353 char *buf, *cp, *oldenv;
354 int namelen, vallen, i;
355
356 KENV_CHECK;
357
358 namelen = strlen(name) + 1;
359 if (namelen > KENV_MNAMELEN)
360 return (-1);
361 vallen = strlen(value) + 1;
362 if (vallen > KENV_MVALLEN)
363 return (-1);
364 buf = malloc(namelen + vallen, M_KENV, M_WAITOK);
365 sprintf(buf, "%s=%s", name, value);
366
367 mtx_lock(&kenv_lock);
368 cp = _getenv_dynamic(name, &i);
369 if (cp != NULL) {
370 oldenv = kenvp[i];
371 kenvp[i] = buf;
372 mtx_unlock(&kenv_lock);
373 free(oldenv, M_KENV);
374 } else {
375 /* We add the option if it wasn't found */
376 for (i = 0; (cp = kenvp[i]) != NULL; i++)
377 ;
378
379 /* Bounds checking */
380 if (i < 0 || i >= KENV_SIZE) {
381 free(buf, M_KENV);
382 mtx_unlock(&kenv_lock);
383 return (-1);
384 }
385
386 kenvp[i] = buf;
387 kenvp[i + 1] = NULL;
388 mtx_unlock(&kenv_lock);
389 }
390 return (0);
391 }
392
393 /*
394 * Unset an environment variable string.
395 */
396 int
397 unsetenv(const char *name)
398 {
399 char *cp, *oldenv;
400 int i, j;
401
402 KENV_CHECK;
403
404 mtx_lock(&kenv_lock);
405 cp = _getenv_dynamic(name, &i);
406 if (cp != NULL) {
407 oldenv = kenvp[i];
408 for (j = i + 1; kenvp[j] != NULL; j++)
409 kenvp[i++] = kenvp[j];
410 kenvp[i] = NULL;
411 mtx_unlock(&kenv_lock);
412 free(oldenv, M_KENV);
413 return (0);
414 }
415 mtx_unlock(&kenv_lock);
416 return (-1);
417 }
418
419 /*
420 * Return a string value from an environment variable.
421 */
422 int
423 getenv_string(const char *name, char *data, int size)
424 {
425 char *tmp;
426
427 tmp = getenv(name);
428 if (tmp != NULL) {
429 strlcpy(data, tmp, size);
430 freeenv(tmp);
431 return (1);
432 } else
433 return (0);
434 }
435
436 /*
437 * Return an integer value from an environment variable.
438 */
439 int
440 getenv_int(const char *name, int *data)
441 {
442 quad_t tmp;
443 int rval;
444
445 rval = getenv_quad(name, &tmp);
446 if (rval)
447 *data = (int) tmp;
448 return (rval);
449 }
450
451 /*
452 * Return a long value from an environment variable.
453 */
454 long
455 getenv_long(const char *name, long *data)
456 {
457 quad_t tmp;
458 long rval;
459
460 rval = getenv_quad(name, &tmp);
461 if (rval)
462 *data = (long) tmp;
463 return (rval);
464 }
465
466 /*
467 * Return an unsigned long value from an environment variable.
468 */
469 unsigned long
470 getenv_ulong(const char *name, unsigned long *data)
471 {
472 quad_t tmp;
473 long rval;
474
475 rval = getenv_quad(name, &tmp);
476 if (rval)
477 *data = (unsigned long) tmp;
478 return (rval);
479 }
480
481 /*
482 * Return a quad_t value from an environment variable.
483 */
484 int
485 getenv_quad(const char *name, quad_t *data)
486 {
487 char *value;
488 char *vtp;
489 quad_t iv;
490
491 value = getenv(name);
492 if (value == NULL)
493 return (0);
494 iv = strtoq(value, &vtp, 0);
495 if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0')) {
496 freeenv(value);
497 return (0);
498 }
499 switch (vtp[0]) {
500 case 't': case 'T':
501 iv *= 1024;
502 case 'g': case 'G':
503 iv *= 1024;
504 case 'm': case 'M':
505 iv *= 1024;
506 case 'k': case 'K':
507 iv *= 1024;
508 case '\0':
509 break;
510 default:
511 freeenv(value);
512 return (0);
513 }
514 *data = iv;
515 freeenv(value);
516 return (1);
517 }
518
519 /*
520 * Find the next entry after the one which (cp) falls within, return a
521 * pointer to its start or NULL if there are no more.
522 */
523 static char *
524 kernenv_next(char *cp)
525 {
526
527 if (cp != NULL) {
528 while (*cp != 0)
529 cp++;
530 cp++;
531 if (*cp == 0)
532 cp = NULL;
533 }
534 return (cp);
535 }
536
537 void
538 tunable_int_init(void *data)
539 {
540 struct tunable_int *d = (struct tunable_int *)data;
541
542 TUNABLE_INT_FETCH(d->path, d->var);
543 }
544
545 void
546 tunable_long_init(void *data)
547 {
548 struct tunable_long *d = (struct tunable_long *)data;
549
550 TUNABLE_LONG_FETCH(d->path, d->var);
551 }
552
553 void
554 tunable_ulong_init(void *data)
555 {
556 struct tunable_ulong *d = (struct tunable_ulong *)data;
557
558 TUNABLE_ULONG_FETCH(d->path, d->var);
559 }
560
561 void
562 tunable_quad_init(void *data)
563 {
564 struct tunable_quad *d = (struct tunable_quad *)data;
565
566 TUNABLE_QUAD_FETCH(d->path, d->var);
567 }
568
569 void
570 tunable_str_init(void *data)
571 {
572 struct tunable_str *d = (struct tunable_str *)data;
573
574 TUNABLE_STR_FETCH(d->path, d->var, d->size);
575 }
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