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