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