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/6.2/sys/kern/kern_environment.c 164286 2006-11-14 20:42:41Z cvs2svn $");
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/mac.h>
48 #include <sys/malloc.h>
49 #include <sys/mutex.h>
50 #include <sys/kernel.h>
51 #include <sys/sx.h>
52 #include <sys/systm.h>
53 #include <sys/sysent.h>
54 #include <sys/sysproto.h>
55 #include <sys/libkern.h>
56 #include <sys/kenv.h>
57
58 static MALLOC_DEFINE(M_KENV, "kenv", "kernel environment");
59
60 #define KENV_SIZE 512 /* Maximum number of environment strings */
61
62 /* pointer to the static environment */
63 char *kern_envp;
64 static char *kernenv_next(char *);
65
66 /* dynamic environment variables */
67 char **kenvp;
68 struct sx kenv_lock;
69
70 /*
71 * No need to protect this with a mutex
72 * 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;
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_check_kenv_dump(td->td_ucred);
99 if (error)
100 return (error);
101 #endif
102 done = needed = 0;
103 sx_slock(&kenv_lock);
104 for (i = 0; kenvp[i] != NULL; i++) {
105 len = strlen(kenvp[i]) + 1;
106 needed += len;
107 len = min(len, uap->len - done);
108 /*
109 * If called with a NULL or insufficiently large
110 * buffer, just keep computing the required size.
111 */
112 if (uap->value != NULL && len > 0) {
113 error = copyout(kenvp[i], uap->value + done,
114 len);
115 if (error)
116 break;
117 done += len;
118 }
119 }
120 sx_sunlock(&kenv_lock);
121 td->td_retval[0] = ((done == needed) ? 0 : needed);
122 return (error);
123 }
124
125 if ((uap->what == KENV_SET) ||
126 (uap->what == KENV_UNSET)) {
127 error = suser(td);
128 if (error)
129 return (error);
130 }
131
132 name = malloc(KENV_MNAMELEN, M_TEMP, M_WAITOK);
133
134 error = copyinstr(uap->name, name, KENV_MNAMELEN, NULL);
135 if (error)
136 goto done;
137
138 switch (uap->what) {
139 case KENV_GET:
140 #ifdef MAC
141 error = mac_check_kenv_get(td->td_ucred, name);
142 if (error)
143 goto done;
144 #endif
145 value = getenv(name);
146 if (value == NULL) {
147 error = ENOENT;
148 goto done;
149 }
150 len = strlen(value) + 1;
151 if (len > uap->len)
152 len = uap->len;
153 error = copyout(value, uap->value, len);
154 freeenv(value);
155 if (error)
156 goto done;
157 td->td_retval[0] = len;
158 break;
159 case KENV_SET:
160 len = uap->len;
161 if (len < 1) {
162 error = EINVAL;
163 goto done;
164 }
165 if (len > KENV_MVALLEN)
166 len = KENV_MVALLEN;
167 value = malloc(len, M_TEMP, M_WAITOK);
168 error = copyinstr(uap->value, value, len, NULL);
169 if (error) {
170 free(value, M_TEMP);
171 goto done;
172 }
173 #ifdef MAC
174 error = mac_check_kenv_set(td->td_ucred, name, value);
175 if (error == 0)
176 #endif
177 setenv(name, value);
178 free(value, M_TEMP);
179 break;
180 case KENV_UNSET:
181 #ifdef MAC
182 error = mac_check_kenv_unset(td->td_ucred, name);
183 if (error)
184 goto done;
185 #endif
186 error = unsetenv(name);
187 if (error)
188 error = ENOENT;
189 break;
190 default:
191 error = EINVAL;
192 break;
193 }
194 done:
195 free(name, M_TEMP);
196 return (error);
197 }
198
199 /*
200 * Setup the dynamic kernel environment.
201 */
202 static void
203 init_dynamic_kenv(void *data __unused)
204 {
205 char *cp;
206 int len, i;
207
208 kenvp = malloc((KENV_SIZE + 1) * sizeof(char *), M_KENV,
209 M_WAITOK | M_ZERO);
210 i = 0;
211 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) {
212 len = strlen(cp) + 1;
213 kenvp[i] = malloc(len, M_KENV, M_WAITOK);
214 strcpy(kenvp[i++], cp);
215 }
216 kenvp[i] = NULL;
217
218 sx_init(&kenv_lock, "kernel environment");
219 dynamic_kenv = 1;
220 }
221 SYSINIT(kenv, SI_SUB_KMEM, SI_ORDER_ANY, init_dynamic_kenv, NULL);
222
223 void
224 freeenv(char *env)
225 {
226
227 if (dynamic_kenv)
228 free(env, M_KENV);
229 }
230
231 /*
232 * Internal functions for string lookup.
233 */
234 static char *
235 _getenv_dynamic(const char *name, int *idx)
236 {
237 char *cp;
238 int len, i;
239
240 sx_assert(&kenv_lock, SX_LOCKED);
241 len = strlen(name);
242 for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) {
243 if ((strncmp(cp, name, len) == 0) &&
244 (cp[len] == '=')) {
245 if (idx != NULL)
246 *idx = i;
247 return (cp + len + 1);
248 }
249 }
250 return (NULL);
251 }
252
253 static char *
254 _getenv_static(const char *name)
255 {
256 char *cp, *ep;
257 int len;
258
259 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) {
260 for (ep = cp; (*ep != '=') && (*ep != 0); ep++)
261 ;
262 if (*ep != '=')
263 continue;
264 len = ep - cp;
265 ep++;
266 if (!strncmp(name, cp, len) && name[len] == 0)
267 return (ep);
268 }
269 return (NULL);
270 }
271
272 /*
273 * Look up an environment variable by name.
274 * Return a pointer to the string if found.
275 * The pointer has to be freed with freeenv()
276 * after use.
277 */
278 char *
279 getenv(const char *name)
280 {
281 char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1];
282 char *ret, *cp;
283 int len;
284
285 if (dynamic_kenv) {
286 sx_slock(&kenv_lock);
287 cp = _getenv_dynamic(name, NULL);
288 if (cp != NULL) {
289 strcpy(buf, cp);
290 sx_sunlock(&kenv_lock);
291 len = strlen(buf) + 1;
292 ret = malloc(len, M_KENV, M_WAITOK);
293 strcpy(ret, buf);
294 } else {
295 sx_sunlock(&kenv_lock);
296 ret = NULL;
297 }
298 } else
299 ret = _getenv_static(name);
300 return (ret);
301 }
302
303 /*
304 * Test if an environment variable is defined.
305 */
306 int
307 testenv(const char *name)
308 {
309 char *cp;
310
311 if (dynamic_kenv) {
312 sx_slock(&kenv_lock);
313 cp = _getenv_dynamic(name, NULL);
314 sx_sunlock(&kenv_lock);
315 } else
316 cp = _getenv_static(name);
317 if (cp != NULL)
318 return (1);
319 return (0);
320 }
321
322 /*
323 * Set an environment variable by name.
324 */
325 int
326 setenv(const char *name, const char *value)
327 {
328 char *buf, *cp, *oldenv;
329 int namelen, vallen, i;
330
331 KENV_CHECK;
332
333 namelen = strlen(name) + 1;
334 if (namelen > KENV_MNAMELEN)
335 return (-1);
336 vallen = strlen(value) + 1;
337 if (vallen > KENV_MVALLEN)
338 return (-1);
339 buf = malloc(namelen + vallen, M_KENV, M_WAITOK);
340 sprintf(buf, "%s=%s", name, value);
341
342 sx_xlock(&kenv_lock);
343 cp = _getenv_dynamic(name, &i);
344 if (cp != NULL) {
345 oldenv = kenvp[i];
346 kenvp[i] = buf;
347 sx_xunlock(&kenv_lock);
348 free(oldenv, M_KENV);
349 } else {
350 /* We add the option if it wasn't found */
351 for (i = 0; (cp = kenvp[i]) != NULL; i++)
352 ;
353
354 /* Bounds checking */
355 if (i < 0 || i >= KENV_SIZE) {
356 free(buf, M_KENV);
357 sx_xunlock(&kenv_lock);
358 return (-1);
359 }
360
361 kenvp[i] = buf;
362 kenvp[i + 1] = NULL;
363 sx_xunlock(&kenv_lock);
364 }
365 return (0);
366 }
367
368 /*
369 * Unset an environment variable string.
370 */
371 int
372 unsetenv(const char *name)
373 {
374 char *cp, *oldenv;
375 int i, j;
376
377 KENV_CHECK;
378
379 sx_xlock(&kenv_lock);
380 cp = _getenv_dynamic(name, &i);
381 if (cp != NULL) {
382 oldenv = kenvp[i];
383 for (j = i + 1; kenvp[j] != NULL; j++)
384 kenvp[i++] = kenvp[j];
385 kenvp[i] = NULL;
386 sx_xunlock(&kenv_lock);
387 free(oldenv, M_KENV);
388 return (0);
389 }
390 sx_xunlock(&kenv_lock);
391 return (-1);
392 }
393
394 /*
395 * Return a string value from an environment variable.
396 */
397 int
398 getenv_string(const char *name, char *data, int size)
399 {
400 char *tmp;
401
402 tmp = getenv(name);
403 if (tmp != NULL) {
404 strlcpy(data, tmp, size);
405 freeenv(tmp);
406 return (1);
407 } else
408 return (0);
409 }
410
411 /*
412 * Return an integer value from an environment variable.
413 */
414 int
415 getenv_int(const char *name, int *data)
416 {
417 quad_t tmp;
418 int rval;
419
420 rval = getenv_quad(name, &tmp);
421 if (rval)
422 *data = (int) tmp;
423 return (rval);
424 }
425
426 /*
427 * Return a long value from an environment variable.
428 */
429 long
430 getenv_long(const char *name, long *data)
431 {
432 quad_t tmp;
433 long rval;
434
435 rval = getenv_quad(name, &tmp);
436 if (rval)
437 *data = (long) tmp;
438 return (rval);
439 }
440
441 /*
442 * Return an unsigned long value from an environment variable.
443 */
444 unsigned long
445 getenv_ulong(const char *name, unsigned long *data)
446 {
447 quad_t tmp;
448 long rval;
449
450 rval = getenv_quad(name, &tmp);
451 if (rval)
452 *data = (unsigned long) tmp;
453 return (rval);
454 }
455
456 /*
457 * Return a quad_t value from an environment variable.
458 */
459 int
460 getenv_quad(const char *name, quad_t *data)
461 {
462 char *value;
463 char *vtp;
464 quad_t iv;
465
466 value = getenv(name);
467 if (value == NULL)
468 return (0);
469 iv = strtoq(value, &vtp, 0);
470 if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0')) {
471 freeenv(value);
472 return (0);
473 }
474 switch (vtp[0]) {
475 case 't': case 'T':
476 iv *= 1024;
477 case 'g': case 'G':
478 iv *= 1024;
479 case 'm': case 'M':
480 iv *= 1024;
481 case 'k': case 'K':
482 iv *= 1024;
483 case '\0':
484 break;
485 default:
486 freeenv(value);
487 return (0);
488 }
489 *data = iv;
490 freeenv(value);
491 return (1);
492 }
493
494 /*
495 * Find the next entry after the one which (cp) falls within, return a
496 * pointer to its start or NULL if there are no more.
497 */
498 static char *
499 kernenv_next(char *cp)
500 {
501
502 if (cp != NULL) {
503 while (*cp != 0)
504 cp++;
505 cp++;
506 if (*cp == 0)
507 cp = NULL;
508 }
509 return (cp);
510 }
511
512 void
513 tunable_int_init(void *data)
514 {
515 struct tunable_int *d = (struct tunable_int *)data;
516
517 TUNABLE_INT_FETCH(d->path, d->var);
518 }
519
520 void
521 tunable_long_init(void *data)
522 {
523 struct tunable_long *d = (struct tunable_long *)data;
524
525 TUNABLE_LONG_FETCH(d->path, d->var);
526 }
527
528 void
529 tunable_ulong_init(void *data)
530 {
531 struct tunable_ulong *d = (struct tunable_ulong *)data;
532
533 TUNABLE_ULONG_FETCH(d->path, d->var);
534 }
535
536 void
537 tunable_str_init(void *data)
538 {
539 struct tunable_str *d = (struct tunable_str *)data;
540
541 TUNABLE_STR_FETCH(d->path, d->var, d->size);
542 }
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