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 sys_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 + 1, M_TEMP, M_WAITOK); 147 148 error = copyinstr(uap->name, name, KENV_MNAMELEN + 1, 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 + 1) 180 len = KENV_MVALLEN + 1; 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 size_t len; 229 int i; 230 231 kenvp = malloc((KENV_SIZE + 1) * sizeof(char *), M_KENV, 232 M_WAITOK | M_ZERO); 233 i = 0; 234 if (kern_envp && *kern_envp != '\0') { 235 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) { 236 len = strlen(cp) + 1; 237 if (len > KENV_MNAMELEN + 1 + KENV_MVALLEN + 1) { 238 printf( 239 "WARNING: too long kenv string, ignoring %s\n", 240 cp); 241 continue; 242 } 243 if (i < KENV_SIZE) { 244 kenvp[i] = malloc(len, M_KENV, M_WAITOK); 245 strcpy(kenvp[i++], cp); 246 } else 247 printf( 248 "WARNING: too many kenv strings, ignoring %s\n", 249 cp); 250 } 251 } 252 kenvp[i] = NULL; 253 254 mtx_init(&kenv_lock, "kernel environment", NULL, MTX_DEF); 255 dynamic_kenv = 1; 256 } 257 SYSINIT(kenv, SI_SUB_KMEM, SI_ORDER_ANY, init_dynamic_kenv, NULL); 258 259 void 260 freeenv(char *env) 261 { 262 263 if (dynamic_kenv) 264 free(env, M_KENV); 265 } 266 267 /* 268 * Internal functions for string lookup. 269 */ 270 static char * 271 _getenv_dynamic(const char *name, int *idx) 272 { 273 char *cp; 274 int len, i; 275 276 mtx_assert(&kenv_lock, MA_OWNED); 277 len = strlen(name); 278 for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) { 279 if ((strncmp(cp, name, len) == 0) && 280 (cp[len] == '=')) { 281 if (idx != NULL) 282 *idx = i; 283 return (cp + len + 1); 284 } 285 } 286 return (NULL); 287 } 288 289 static char * 290 _getenv_static(const char *name) 291 { 292 char *cp, *ep; 293 int len; 294 295 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) { 296 for (ep = cp; (*ep != '=') && (*ep != 0); ep++) 297 ; 298 if (*ep != '=') 299 continue; 300 len = ep - cp; 301 ep++; 302 if (!strncmp(name, cp, len) && name[len] == 0) 303 return (ep); 304 } 305 return (NULL); 306 } 307 308 /* 309 * Look up an environment variable by name. 310 * Return a pointer to the string if found. 311 * The pointer has to be freed with freeenv() 312 * after use. 313 */ 314 char * 315 getenv(const char *name) 316 { 317 char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1]; 318 char *ret, *cp; 319 int len; 320 321 if (dynamic_kenv) { 322 mtx_lock(&kenv_lock); 323 cp = _getenv_dynamic(name, NULL); 324 if (cp != NULL) { 325 strcpy(buf, cp); 326 mtx_unlock(&kenv_lock); 327 len = strlen(buf) + 1; 328 ret = malloc(len, M_KENV, M_WAITOK); 329 strcpy(ret, buf); 330 } else { 331 mtx_unlock(&kenv_lock); 332 ret = NULL; 333 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, 334 "getenv"); 335 } 336 } else 337 ret = _getenv_static(name); 338 return (ret); 339 } 340 341 /* 342 * Test if an environment variable is defined. 343 */ 344 int 345 testenv(const char *name) 346 { 347 char *cp; 348 349 if (dynamic_kenv) { 350 mtx_lock(&kenv_lock); 351 cp = _getenv_dynamic(name, NULL); 352 mtx_unlock(&kenv_lock); 353 } else 354 cp = _getenv_static(name); 355 if (cp != NULL) 356 return (1); 357 return (0); 358 } 359 360 static int 361 setenv_static(const char *name, const char *value) 362 { 363 int len; 364 365 if (env_pos >= env_len) 366 return (-1); 367 368 /* Check space for x=y and two nuls */ 369 len = strlen(name) + strlen(value); 370 if (len + 3 < env_len - env_pos) { 371 len = sprintf(&kern_envp[env_pos], "%s=%s", name, value); 372 env_pos += len+1; 373 kern_envp[env_pos] = '\0'; 374 return (0); 375 } else 376 return (-1); 377 378 } 379 380 /* 381 * Set an environment variable by name. 382 */ 383 int 384 setenv(const char *name, const char *value) 385 { 386 char *buf, *cp, *oldenv; 387 int namelen, vallen, i; 388 389 if (dynamic_kenv == 0 && env_len > 0) 390 return (setenv_static(name, value)); 391 392 KENV_CHECK; 393 394 namelen = strlen(name) + 1; 395 if (namelen > KENV_MNAMELEN + 1) 396 return (-1); 397 vallen = strlen(value) + 1; 398 if (vallen > KENV_MVALLEN + 1) 399 return (-1); 400 buf = malloc(namelen + vallen, M_KENV, M_WAITOK); 401 sprintf(buf, "%s=%s", name, value); 402 403 mtx_lock(&kenv_lock); 404 cp = _getenv_dynamic(name, &i); 405 if (cp != NULL) { 406 oldenv = kenvp[i]; 407 kenvp[i] = buf; 408 mtx_unlock(&kenv_lock); 409 free(oldenv, M_KENV); 410 } else { 411 /* We add the option if it wasn't found */ 412 for (i = 0; (cp = kenvp[i]) != NULL; i++) 413 ; 414 415 /* Bounds checking */ 416 if (i < 0 || i >= KENV_SIZE) { 417 free(buf, M_KENV); 418 mtx_unlock(&kenv_lock); 419 return (-1); 420 } 421 422 kenvp[i] = buf; 423 kenvp[i + 1] = NULL; 424 mtx_unlock(&kenv_lock); 425 } 426 return (0); 427 } 428 429 /* 430 * Unset an environment variable string. 431 */ 432 int 433 unsetenv(const char *name) 434 { 435 char *cp, *oldenv; 436 int i, j; 437 438 KENV_CHECK; 439 440 mtx_lock(&kenv_lock); 441 cp = _getenv_dynamic(name, &i); 442 if (cp != NULL) { 443 oldenv = kenvp[i]; 444 for (j = i + 1; kenvp[j] != NULL; j++) 445 kenvp[i++] = kenvp[j]; 446 kenvp[i] = NULL; 447 mtx_unlock(&kenv_lock); 448 free(oldenv, M_KENV); 449 return (0); 450 } 451 mtx_unlock(&kenv_lock); 452 return (-1); 453 } 454 455 /* 456 * Return a string value from an environment variable. 457 */ 458 int 459 getenv_string(const char *name, char *data, int size) 460 { 461 char *tmp; 462 463 tmp = getenv(name); 464 if (tmp != NULL) { 465 strlcpy(data, tmp, size); 466 freeenv(tmp); 467 return (1); 468 } else 469 return (0); 470 } 471 472 /* 473 * Return an integer value from an environment variable. 474 */ 475 int 476 getenv_int(const char *name, int *data) 477 { 478 quad_t tmp; 479 int rval; 480 481 rval = getenv_quad(name, &tmp); 482 if (rval) 483 *data = (int) tmp; 484 return (rval); 485 } 486 487 /* 488 * Return an unsigned integer value from an environment variable. 489 */ 490 int 491 getenv_uint(const char *name, unsigned int *data) 492 { 493 quad_t tmp; 494 int rval; 495 496 rval = getenv_quad(name, &tmp); 497 if (rval) 498 *data = (unsigned int) tmp; 499 return (rval); 500 } 501 502 /* 503 * Return a long value from an environment variable. 504 */ 505 int 506 getenv_long(const char *name, long *data) 507 { 508 quad_t tmp; 509 int rval; 510 511 rval = getenv_quad(name, &tmp); 512 if (rval) 513 *data = (long) tmp; 514 return (rval); 515 } 516 517 /* 518 * Return an unsigned long value from an environment variable. 519 */ 520 int 521 getenv_ulong(const char *name, unsigned long *data) 522 { 523 quad_t tmp; 524 int rval; 525 526 rval = getenv_quad(name, &tmp); 527 if (rval) 528 *data = (unsigned long) tmp; 529 return (rval); 530 } 531 532 /* 533 * Return a quad_t value from an environment variable. 534 */ 535 int 536 getenv_quad(const char *name, quad_t *data) 537 { 538 char *value; 539 char *vtp; 540 quad_t iv; 541 542 value = getenv(name); 543 if (value == NULL) 544 return (0); 545 iv = strtoq(value, &vtp, 0); 546 if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0')) { 547 freeenv(value); 548 return (0); 549 } 550 switch (vtp[0]) { 551 case 't': case 'T': 552 iv *= 1024; 553 case 'g': case 'G': 554 iv *= 1024; 555 case 'm': case 'M': 556 iv *= 1024; 557 case 'k': case 'K': 558 iv *= 1024; 559 case '\0': 560 break; 561 default: 562 freeenv(value); 563 return (0); 564 } 565 *data = iv; 566 freeenv(value); 567 return (1); 568 } 569 570 /* 571 * Find the next entry after the one which (cp) falls within, return a 572 * pointer to its start or NULL if there are no more. 573 */ 574 static char * 575 kernenv_next(char *cp) 576 { 577 578 if (cp != NULL) { 579 while (*cp != 0) 580 cp++; 581 cp++; 582 if (*cp == 0) 583 cp = NULL; 584 } 585 return (cp); 586 } 587 588 void 589 tunable_int_init(void *data) 590 { 591 struct tunable_int *d = (struct tunable_int *)data; 592 593 TUNABLE_INT_FETCH(d->path, d->var); 594 } 595 596 void 597 tunable_long_init(void *data) 598 { 599 struct tunable_long *d = (struct tunable_long *)data; 600 601 TUNABLE_LONG_FETCH(d->path, d->var); 602 } 603 604 void 605 tunable_ulong_init(void *data) 606 { 607 struct tunable_ulong *d = (struct tunable_ulong *)data; 608 609 TUNABLE_ULONG_FETCH(d->path, d->var); 610 } 611 612 void 613 tunable_quad_init(void *data) 614 { 615 struct tunable_quad *d = (struct tunable_quad *)data; 616 617 TUNABLE_QUAD_FETCH(d->path, d->var); 618 } 619 620 void 621 tunable_str_init(void *data) 622 { 623 struct tunable_str *d = (struct tunable_str *)data; 624 625 TUNABLE_STR_FETCH(d->path, d->var, d->size); 626 } 627