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 <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 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, 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_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) 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_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 int len, i; 229 230 kenvp = malloc((KENV_SIZE + 1) * sizeof(char *), M_KENV, 231 M_WAITOK | M_ZERO); 232 i = 0; 233 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) { 234 len = strlen(cp) + 1; 235 if (i < KENV_SIZE) { 236 kenvp[i] = malloc(len, M_KENV, M_WAITOK); 237 strcpy(kenvp[i++], cp); 238 } else 239 printf( 240 "WARNING: too many kenv strings, ignoring %s\n", 241 cp); 242 } 243 kenvp[i] = NULL; 244 245 mtx_init(&kenv_lock, "kernel environment", NULL, MTX_DEF); 246 dynamic_kenv = 1; 247 } 248 SYSINIT(kenv, SI_SUB_KMEM, SI_ORDER_ANY, init_dynamic_kenv, NULL); 249 250 void 251 freeenv(char *env) 252 { 253 254 if (dynamic_kenv) 255 free(env, M_KENV); 256 } 257 258 /* 259 * Internal functions for string lookup. 260 */ 261 static char * 262 _getenv_dynamic(const char *name, int *idx) 263 { 264 char *cp; 265 int len, i; 266 267 mtx_assert(&kenv_lock, MA_OWNED); 268 len = strlen(name); 269 for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) { 270 if ((strncmp(cp, name, len) == 0) && 271 (cp[len] == '=')) { 272 if (idx != NULL) 273 *idx = i; 274 return (cp + len + 1); 275 } 276 } 277 return (NULL); 278 } 279 280 static char * 281 _getenv_static(const char *name) 282 { 283 char *cp, *ep; 284 int len; 285 286 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) { 287 for (ep = cp; (*ep != '=') && (*ep != 0); ep++) 288 ; 289 if (*ep != '=') 290 continue; 291 len = ep - cp; 292 ep++; 293 if (!strncmp(name, cp, len) && name[len] == 0) 294 return (ep); 295 } 296 return (NULL); 297 } 298 299 /* 300 * Look up an environment variable by name. 301 * Return a pointer to the string if found. 302 * The pointer has to be freed with freeenv() 303 * after use. 304 */ 305 char * 306 getenv(const char *name) 307 { 308 char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1]; 309 char *ret, *cp; 310 int len; 311 312 if (dynamic_kenv) { 313 mtx_lock(&kenv_lock); 314 cp = _getenv_dynamic(name, NULL); 315 if (cp != NULL) { 316 strcpy(buf, cp); 317 mtx_unlock(&kenv_lock); 318 len = strlen(buf) + 1; 319 ret = malloc(len, M_KENV, M_WAITOK); 320 strcpy(ret, buf); 321 } else { 322 mtx_unlock(&kenv_lock); 323 ret = NULL; 324 } 325 } else 326 ret = _getenv_static(name); 327 return (ret); 328 } 329 330 /* 331 * Test if an environment variable is defined. 332 */ 333 int 334 testenv(const char *name) 335 { 336 char *cp; 337 338 if (dynamic_kenv) { 339 mtx_lock(&kenv_lock); 340 cp = _getenv_dynamic(name, NULL); 341 mtx_unlock(&kenv_lock); 342 } else 343 cp = _getenv_static(name); 344 if (cp != NULL) 345 return (1); 346 return (0); 347 } 348 349 static int 350 setenv_static(const char *name, const char *value) 351 { 352 int len; 353 354 if (env_pos >= env_len) 355 return (-1); 356 357 /* Check space for x=y and two nuls */ 358 len = strlen(name) + strlen(value); 359 if (len + 3 < env_len - env_pos) { 360 len = sprintf(&kern_envp[env_pos], "%s=%s", name, value); 361 env_pos += len+1; 362 kern_envp[env_pos] = '\0'; 363 return (0); 364 } else 365 return (-1); 366 367 } 368 369 /* 370 * Set an environment variable by name. 371 */ 372 int 373 setenv(const char *name, const char *value) 374 { 375 char *buf, *cp, *oldenv; 376 int namelen, vallen, i; 377 378 if (dynamic_kenv == 0 && env_len > 0) 379 return (setenv_static(name, value)); 380 381 KENV_CHECK; 382 383 namelen = strlen(name) + 1; 384 if (namelen > KENV_MNAMELEN) 385 return (-1); 386 vallen = strlen(value) + 1; 387 if (vallen > KENV_MVALLEN) 388 return (-1); 389 buf = malloc(namelen + vallen, M_KENV, M_WAITOK); 390 sprintf(buf, "%s=%s", name, value); 391 392 mtx_lock(&kenv_lock); 393 cp = _getenv_dynamic(name, &i); 394 if (cp != NULL) { 395 oldenv = kenvp[i]; 396 kenvp[i] = buf; 397 mtx_unlock(&kenv_lock); 398 free(oldenv, M_KENV); 399 } else { 400 /* We add the option if it wasn't found */ 401 for (i = 0; (cp = kenvp[i]) != NULL; i++) 402 ; 403 404 /* Bounds checking */ 405 if (i < 0 || i >= KENV_SIZE) { 406 free(buf, M_KENV); 407 mtx_unlock(&kenv_lock); 408 return (-1); 409 } 410 411 kenvp[i] = buf; 412 kenvp[i + 1] = NULL; 413 mtx_unlock(&kenv_lock); 414 } 415 return (0); 416 } 417 418 /* 419 * Unset an environment variable string. 420 */ 421 int 422 unsetenv(const char *name) 423 { 424 char *cp, *oldenv; 425 int i, j; 426 427 KENV_CHECK; 428 429 mtx_lock(&kenv_lock); 430 cp = _getenv_dynamic(name, &i); 431 if (cp != NULL) { 432 oldenv = kenvp[i]; 433 for (j = i + 1; kenvp[j] != NULL; j++) 434 kenvp[i++] = kenvp[j]; 435 kenvp[i] = NULL; 436 mtx_unlock(&kenv_lock); 437 free(oldenv, M_KENV); 438 return (0); 439 } 440 mtx_unlock(&kenv_lock); 441 return (-1); 442 } 443 444 /* 445 * Return a string value from an environment variable. 446 */ 447 int 448 getenv_string(const char *name, char *data, int size) 449 { 450 char *tmp; 451 452 tmp = getenv(name); 453 if (tmp != NULL) { 454 strlcpy(data, tmp, size); 455 freeenv(tmp); 456 return (1); 457 } else 458 return (0); 459 } 460 461 /* 462 * Return an integer value from an environment variable. 463 */ 464 int 465 getenv_int(const char *name, int *data) 466 { 467 quad_t tmp; 468 int rval; 469 470 rval = getenv_quad(name, &tmp); 471 if (rval) 472 *data = (int) tmp; 473 return (rval); 474 } 475 476 /* 477 * Return an unsigned integer value from an environment variable. 478 */ 479 int 480 getenv_uint(const char *name, unsigned int *data) 481 { 482 quad_t tmp; 483 int rval; 484 485 rval = getenv_quad(name, &tmp); 486 if (rval) 487 *data = (unsigned int) tmp; 488 return (rval); 489 } 490 491 /* 492 * Return a long value from an environment variable. 493 */ 494 int 495 getenv_long(const char *name, long *data) 496 { 497 quad_t tmp; 498 int rval; 499 500 rval = getenv_quad(name, &tmp); 501 if (rval) 502 *data = (long) tmp; 503 return (rval); 504 } 505 506 /* 507 * Return an unsigned long value from an environment variable. 508 */ 509 int 510 getenv_ulong(const char *name, unsigned long *data) 511 { 512 quad_t tmp; 513 int rval; 514 515 rval = getenv_quad(name, &tmp); 516 if (rval) 517 *data = (unsigned long) tmp; 518 return (rval); 519 } 520 521 /* 522 * Return a quad_t value from an environment variable. 523 */ 524 int 525 getenv_quad(const char *name, quad_t *data) 526 { 527 char *value; 528 char *vtp; 529 quad_t iv; 530 531 value = getenv(name); 532 if (value == NULL) 533 return (0); 534 iv = strtoq(value, &vtp, 0); 535 if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0')) { 536 freeenv(value); 537 return (0); 538 } 539 switch (vtp[0]) { 540 case 't': case 'T': 541 iv *= 1024; 542 case 'g': case 'G': 543 iv *= 1024; 544 case 'm': case 'M': 545 iv *= 1024; 546 case 'k': case 'K': 547 iv *= 1024; 548 case '\0': 549 break; 550 default: 551 freeenv(value); 552 return (0); 553 } 554 *data = iv; 555 freeenv(value); 556 return (1); 557 } 558 559 /* 560 * Find the next entry after the one which (cp) falls within, return a 561 * pointer to its start or NULL if there are no more. 562 */ 563 static char * 564 kernenv_next(char *cp) 565 { 566 567 if (cp != NULL) { 568 while (*cp != 0) 569 cp++; 570 cp++; 571 if (*cp == 0) 572 cp = NULL; 573 } 574 return (cp); 575 } 576 577 void 578 tunable_int_init(void *data) 579 { 580 struct tunable_int *d = (struct tunable_int *)data; 581 582 TUNABLE_INT_FETCH(d->path, d->var); 583 } 584 585 void 586 tunable_long_init(void *data) 587 { 588 struct tunable_long *d = (struct tunable_long *)data; 589 590 TUNABLE_LONG_FETCH(d->path, d->var); 591 } 592 593 void 594 tunable_ulong_init(void *data) 595 { 596 struct tunable_ulong *d = (struct tunable_ulong *)data; 597 598 TUNABLE_ULONG_FETCH(d->path, d->var); 599 } 600 601 void 602 tunable_quad_init(void *data) 603 { 604 struct tunable_quad *d = (struct tunable_quad *)data; 605 606 TUNABLE_QUAD_FETCH(d->path, d->var); 607 } 608 609 void 610 tunable_str_init(void *data) 611 { 612 struct tunable_str *d = (struct tunable_str *)data; 613 614 TUNABLE_STR_FETCH(d->path, d->var, d->size); 615 } 616