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; 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 if (uap->len > 0 && uap->value != NULL) 104 buffer = malloc(uap->len, M_TEMP, M_WAITOK|M_ZERO); 105 mtx_lock(&kenv_lock); 106 for (i = 0; kenvp[i] != NULL; i++) { 107 len = strlen(kenvp[i]) + 1; 108 needed += len; 109 len = min(len, uap->len - done); 110 /* 111 * If called with a NULL or insufficiently large 112 * buffer, just keep computing the required size. 113 */ 114 if (uap->value != NULL && buffer != NULL && len > 0) { 115 bcopy(kenvp[i], buffer + done, len); 116 done += len; 117 } 118 } 119 mtx_unlock(&kenv_lock); 120 if (buffer != NULL) { 121 error = copyout(buffer, uap->value, done); 122 free(buffer, M_TEMP); 123 } 124 td->td_retval[0] = ((done == needed) ? 0 : needed); 125 return (error); 126 } 127 128 switch (uap->what) { 129 case KENV_SET: 130 error = priv_check(td, PRIV_KENV_SET); 131 if (error) 132 return (error); 133 break; 134 135 case KENV_UNSET: 136 error = priv_check(td, PRIV_KENV_UNSET); 137 if (error) 138 return (error); 139 break; 140 } 141 142 name = malloc(KENV_MNAMELEN, M_TEMP, M_WAITOK); 143 144 error = copyinstr(uap->name, name, KENV_MNAMELEN, NULL); 145 if (error) 146 goto done; 147 148 switch (uap->what) { 149 case KENV_GET: 150 #ifdef MAC 151 error = mac_kenv_check_get(td->td_ucred, name); 152 if (error) 153 goto done; 154 #endif 155 value = getenv(name); 156 if (value == NULL) { 157 error = ENOENT; 158 goto done; 159 } 160 len = strlen(value) + 1; 161 if (len > uap->len) 162 len = uap->len; 163 error = copyout(value, uap->value, len); 164 freeenv(value); 165 if (error) 166 goto done; 167 td->td_retval[0] = len; 168 break; 169 case KENV_SET: 170 len = uap->len; 171 if (len < 1) { 172 error = EINVAL; 173 goto done; 174 } 175 if (len > KENV_MVALLEN) 176 len = KENV_MVALLEN; 177 value = malloc(len, M_TEMP, M_WAITOK); 178 error = copyinstr(uap->value, value, len, NULL); 179 if (error) { 180 free(value, M_TEMP); 181 goto done; 182 } 183 #ifdef MAC 184 error = mac_kenv_check_set(td->td_ucred, name, value); 185 if (error == 0) 186 #endif 187 setenv(name, value); 188 free(value, M_TEMP); 189 break; 190 case KENV_UNSET: 191 #ifdef MAC 192 error = mac_kenv_check_unset(td->td_ucred, name); 193 if (error) 194 goto done; 195 #endif 196 error = unsetenv(name); 197 if (error) 198 error = ENOENT; 199 break; 200 default: 201 error = EINVAL; 202 break; 203 } 204 done: 205 free(name, M_TEMP); 206 return (error); 207 } 208 209 /* 210 * Setup the dynamic kernel environment. 211 */ 212 static void 213 init_dynamic_kenv(void *data __unused) 214 { 215 char *cp; 216 int len, i; 217 218 kenvp = malloc((KENV_SIZE + 1) * sizeof(char *), M_KENV, 219 M_WAITOK | M_ZERO); 220 i = 0; 221 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) { 222 len = strlen(cp) + 1; 223 if (i < KENV_SIZE) { 224 kenvp[i] = malloc(len, M_KENV, M_WAITOK); 225 strcpy(kenvp[i++], cp); 226 } else 227 printf( 228 "WARNING: too many kenv strings, ignoring %s\n", 229 cp); 230 } 231 kenvp[i] = NULL; 232 233 mtx_init(&kenv_lock, "kernel environment", NULL, MTX_DEF); 234 dynamic_kenv = 1; 235 } 236 SYSINIT(kenv, SI_SUB_KMEM, SI_ORDER_ANY, init_dynamic_kenv, NULL); 237 238 void 239 freeenv(char *env) 240 { 241 242 if (dynamic_kenv) 243 free(env, M_KENV); 244 } 245 246 /* 247 * Internal functions for string lookup. 248 */ 249 static char * 250 _getenv_dynamic(const char *name, int *idx) 251 { 252 char *cp; 253 int len, i; 254 255 mtx_assert(&kenv_lock, MA_OWNED); 256 len = strlen(name); 257 for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) { 258 if ((strncmp(cp, name, len) == 0) && 259 (cp[len] == '=')) { 260 if (idx != NULL) 261 *idx = i; 262 return (cp + len + 1); 263 } 264 } 265 return (NULL); 266 } 267 268 static char * 269 _getenv_static(const char *name) 270 { 271 char *cp, *ep; 272 int len; 273 274 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) { 275 for (ep = cp; (*ep != '=') && (*ep != 0); ep++) 276 ; 277 if (*ep != '=') 278 continue; 279 len = ep - cp; 280 ep++; 281 if (!strncmp(name, cp, len) && name[len] == 0) 282 return (ep); 283 } 284 return (NULL); 285 } 286 287 /* 288 * Look up an environment variable by name. 289 * Return a pointer to the string if found. 290 * The pointer has to be freed with freeenv() 291 * after use. 292 */ 293 char * 294 getenv(const char *name) 295 { 296 char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1]; 297 char *ret, *cp; 298 int len; 299 300 if (dynamic_kenv) { 301 mtx_lock(&kenv_lock); 302 cp = _getenv_dynamic(name, NULL); 303 if (cp != NULL) { 304 strcpy(buf, cp); 305 mtx_unlock(&kenv_lock); 306 len = strlen(buf) + 1; 307 ret = malloc(len, M_KENV, M_WAITOK); 308 strcpy(ret, buf); 309 } else { 310 mtx_unlock(&kenv_lock); 311 ret = NULL; 312 } 313 } else 314 ret = _getenv_static(name); 315 return (ret); 316 } 317 318 /* 319 * Test if an environment variable is defined. 320 */ 321 int 322 testenv(const char *name) 323 { 324 char *cp; 325 326 if (dynamic_kenv) { 327 mtx_lock(&kenv_lock); 328 cp = _getenv_dynamic(name, NULL); 329 mtx_unlock(&kenv_lock); 330 } else 331 cp = _getenv_static(name); 332 if (cp != NULL) 333 return (1); 334 return (0); 335 } 336 337 /* 338 * Set an environment variable by name. 339 */ 340 int 341 setenv(const char *name, const char *value) 342 { 343 char *buf, *cp, *oldenv; 344 int namelen, vallen, i; 345 346 KENV_CHECK; 347 348 namelen = strlen(name) + 1; 349 if (namelen > KENV_MNAMELEN) 350 return (-1); 351 vallen = strlen(value) + 1; 352 if (vallen > KENV_MVALLEN) 353 return (-1); 354 buf = malloc(namelen + vallen, M_KENV, M_WAITOK); 355 sprintf(buf, "%s=%s", name, value); 356 357 mtx_lock(&kenv_lock); 358 cp = _getenv_dynamic(name, &i); 359 if (cp != NULL) { 360 oldenv = kenvp[i]; 361 kenvp[i] = buf; 362 mtx_unlock(&kenv_lock); 363 free(oldenv, M_KENV); 364 } else { 365 /* We add the option if it wasn't found */ 366 for (i = 0; (cp = kenvp[i]) != NULL; i++) 367 ; 368 369 /* Bounds checking */ 370 if (i < 0 || i >= KENV_SIZE) { 371 free(buf, M_KENV); 372 mtx_unlock(&kenv_lock); 373 return (-1); 374 } 375 376 kenvp[i] = buf; 377 kenvp[i + 1] = NULL; 378 mtx_unlock(&kenv_lock); 379 } 380 return (0); 381 } 382 383 /* 384 * Unset an environment variable string. 385 */ 386 int 387 unsetenv(const char *name) 388 { 389 char *cp, *oldenv; 390 int i, j; 391 392 KENV_CHECK; 393 394 mtx_lock(&kenv_lock); 395 cp = _getenv_dynamic(name, &i); 396 if (cp != NULL) { 397 oldenv = kenvp[i]; 398 for (j = i + 1; kenvp[j] != NULL; j++) 399 kenvp[i++] = kenvp[j]; 400 kenvp[i] = NULL; 401 mtx_unlock(&kenv_lock); 402 free(oldenv, M_KENV); 403 return (0); 404 } 405 mtx_unlock(&kenv_lock); 406 return (-1); 407 } 408 409 /* 410 * Return a string value from an environment variable. 411 */ 412 int 413 getenv_string(const char *name, char *data, int size) 414 { 415 char *tmp; 416 417 tmp = getenv(name); 418 if (tmp != NULL) { 419 strlcpy(data, tmp, size); 420 freeenv(tmp); 421 return (1); 422 } else 423 return (0); 424 } 425 426 /* 427 * Return an integer value from an environment variable. 428 */ 429 int 430 getenv_int(const char *name, int *data) 431 { 432 quad_t tmp; 433 int rval; 434 435 rval = getenv_quad(name, &tmp); 436 if (rval) 437 *data = (int) tmp; 438 return (rval); 439 } 440 441 /* 442 * Return an unsigned integer value from an environment variable. 443 */ 444 int 445 getenv_uint(const char *name, unsigned int *data) 446 { 447 quad_t tmp; 448 int rval; 449 450 rval = getenv_quad(name, &tmp); 451 if (rval) 452 *data = (unsigned int) tmp; 453 return (rval); 454 } 455 456 /* 457 * Return a long value from an environment variable. 458 */ 459 int 460 getenv_long(const char *name, long *data) 461 { 462 quad_t tmp; 463 int rval; 464 465 rval = getenv_quad(name, &tmp); 466 if (rval) 467 *data = (long) tmp; 468 return (rval); 469 } 470 471 /* 472 * Return an unsigned long value from an environment variable. 473 */ 474 int 475 getenv_ulong(const char *name, unsigned long *data) 476 { 477 quad_t tmp; 478 int rval; 479 480 rval = getenv_quad(name, &tmp); 481 if (rval) 482 *data = (unsigned long) tmp; 483 return (rval); 484 } 485 486 /* 487 * Return a quad_t value from an environment variable. 488 */ 489 int 490 getenv_quad(const char *name, quad_t *data) 491 { 492 char *value; 493 char *vtp; 494 quad_t iv; 495 496 value = getenv(name); 497 if (value == NULL) 498 return (0); 499 iv = strtoq(value, &vtp, 0); 500 if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0')) { 501 freeenv(value); 502 return (0); 503 } 504 switch (vtp[0]) { 505 case 't': case 'T': 506 iv *= 1024; 507 case 'g': case 'G': 508 iv *= 1024; 509 case 'm': case 'M': 510 iv *= 1024; 511 case 'k': case 'K': 512 iv *= 1024; 513 case '\0': 514 break; 515 default: 516 freeenv(value); 517 return (0); 518 } 519 *data = iv; 520 freeenv(value); 521 return (1); 522 } 523 524 /* 525 * Find the next entry after the one which (cp) falls within, return a 526 * pointer to its start or NULL if there are no more. 527 */ 528 static char * 529 kernenv_next(char *cp) 530 { 531 532 if (cp != NULL) { 533 while (*cp != 0) 534 cp++; 535 cp++; 536 if (*cp == 0) 537 cp = NULL; 538 } 539 return (cp); 540 } 541 542 void 543 tunable_int_init(void *data) 544 { 545 struct tunable_int *d = (struct tunable_int *)data; 546 547 TUNABLE_INT_FETCH(d->path, d->var); 548 } 549 550 void 551 tunable_long_init(void *data) 552 { 553 struct tunable_long *d = (struct tunable_long *)data; 554 555 TUNABLE_LONG_FETCH(d->path, d->var); 556 } 557 558 void 559 tunable_ulong_init(void *data) 560 { 561 struct tunable_ulong *d = (struct tunable_ulong *)data; 562 563 TUNABLE_ULONG_FETCH(d->path, d->var); 564 } 565 566 void 567 tunable_quad_init(void *data) 568 { 569 struct tunable_quad *d = (struct tunable_quad *)data; 570 571 TUNABLE_QUAD_FETCH(d->path, d->var); 572 } 573 574 void 575 tunable_str_init(void *data) 576 { 577 struct tunable_str *d = (struct tunable_str *)data; 578 579 TUNABLE_STR_FETCH(d->path, d->var, d->size); 580 } 581