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; 319 320 if (dynamic_kenv) { 321 if (getenv_string(name, buf, sizeof(buf))) { 322 ret = strdup(buf, M_KENV); 323 } else { 324 ret = NULL; 325 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, 326 "getenv"); 327 } 328 } else 329 ret = _getenv_static(name); 330 return (ret); 331 } 332 333 /* 334 * Test if an environment variable is defined. 335 */ 336 int 337 testenv(const char *name) 338 { 339 char *cp; 340 341 if (dynamic_kenv) { 342 mtx_lock(&kenv_lock); 343 cp = _getenv_dynamic(name, NULL); 344 mtx_unlock(&kenv_lock); 345 } else 346 cp = _getenv_static(name); 347 if (cp != NULL) 348 return (1); 349 return (0); 350 } 351 352 static int 353 setenv_static(const char *name, const char *value) 354 { 355 int len; 356 357 if (env_pos >= env_len) 358 return (-1); 359 360 /* Check space for x=y and two nuls */ 361 len = strlen(name) + strlen(value); 362 if (len + 3 < env_len - env_pos) { 363 len = sprintf(&kern_envp[env_pos], "%s=%s", name, value); 364 env_pos += len+1; 365 kern_envp[env_pos] = '\0'; 366 return (0); 367 } else 368 return (-1); 369 370 } 371 372 /* 373 * Set an environment variable by name. 374 */ 375 int 376 setenv(const char *name, const char *value) 377 { 378 char *buf, *cp, *oldenv; 379 int namelen, vallen, i; 380 381 if (dynamic_kenv == 0 && env_len > 0) 382 return (setenv_static(name, value)); 383 384 KENV_CHECK; 385 386 namelen = strlen(name) + 1; 387 if (namelen > KENV_MNAMELEN + 1) 388 return (-1); 389 vallen = strlen(value) + 1; 390 if (vallen > KENV_MVALLEN + 1) 391 return (-1); 392 buf = malloc(namelen + vallen, M_KENV, M_WAITOK); 393 sprintf(buf, "%s=%s", name, value); 394 395 mtx_lock(&kenv_lock); 396 cp = _getenv_dynamic(name, &i); 397 if (cp != NULL) { 398 oldenv = kenvp[i]; 399 kenvp[i] = buf; 400 mtx_unlock(&kenv_lock); 401 free(oldenv, M_KENV); 402 } else { 403 /* We add the option if it wasn't found */ 404 for (i = 0; (cp = kenvp[i]) != NULL; i++) 405 ; 406 407 /* Bounds checking */ 408 if (i < 0 || i >= KENV_SIZE) { 409 free(buf, M_KENV); 410 mtx_unlock(&kenv_lock); 411 return (-1); 412 } 413 414 kenvp[i] = buf; 415 kenvp[i + 1] = NULL; 416 mtx_unlock(&kenv_lock); 417 } 418 return (0); 419 } 420 421 /* 422 * Unset an environment variable string. 423 */ 424 int 425 unsetenv(const char *name) 426 { 427 char *cp, *oldenv; 428 int i, j; 429 430 KENV_CHECK; 431 432 mtx_lock(&kenv_lock); 433 cp = _getenv_dynamic(name, &i); 434 if (cp != NULL) { 435 oldenv = kenvp[i]; 436 for (j = i + 1; kenvp[j] != NULL; j++) 437 kenvp[i++] = kenvp[j]; 438 kenvp[i] = NULL; 439 mtx_unlock(&kenv_lock); 440 free(oldenv, M_KENV); 441 return (0); 442 } 443 mtx_unlock(&kenv_lock); 444 return (-1); 445 } 446 447 /* 448 * Return a string value from an environment variable. 449 */ 450 int 451 getenv_string(const char *name, char *data, int size) 452 { 453 char *cp; 454 455 if (dynamic_kenv) { 456 mtx_lock(&kenv_lock); 457 cp = _getenv_dynamic(name, NULL); 458 if (cp != NULL) 459 strlcpy(data, cp, size); 460 mtx_unlock(&kenv_lock); 461 } else { 462 cp = _getenv_static(name); 463 if (cp != NULL) 464 strlcpy(data, cp, size); 465 } 466 return (cp != NULL); 467 } 468 469 /* 470 * Return an integer value from an environment variable. 471 */ 472 int 473 getenv_int(const char *name, int *data) 474 { 475 quad_t tmp; 476 int rval; 477 478 rval = getenv_quad(name, &tmp); 479 if (rval) 480 *data = (int) tmp; 481 return (rval); 482 } 483 484 /* 485 * Return an unsigned integer value from an environment variable. 486 */ 487 int 488 getenv_uint(const char *name, unsigned int *data) 489 { 490 quad_t tmp; 491 int rval; 492 493 rval = getenv_quad(name, &tmp); 494 if (rval) 495 *data = (unsigned int) tmp; 496 return (rval); 497 } 498 499 /* 500 * Return a long value from an environment variable. 501 */ 502 int 503 getenv_long(const char *name, long *data) 504 { 505 quad_t tmp; 506 int rval; 507 508 rval = getenv_quad(name, &tmp); 509 if (rval) 510 *data = (long) tmp; 511 return (rval); 512 } 513 514 /* 515 * Return an unsigned long value from an environment variable. 516 */ 517 int 518 getenv_ulong(const char *name, unsigned long *data) 519 { 520 quad_t tmp; 521 int rval; 522 523 rval = getenv_quad(name, &tmp); 524 if (rval) 525 *data = (unsigned long) tmp; 526 return (rval); 527 } 528 529 /* 530 * Return a quad_t value from an environment variable. 531 */ 532 int 533 getenv_quad(const char *name, quad_t *data) 534 { 535 char value[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1]; 536 char *vtp; 537 quad_t iv; 538 539 if (!getenv_string(name, value, sizeof(value))) 540 return (0); 541 iv = strtoq(value, &vtp, 0); 542 if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0')) 543 return (0); 544 switch (vtp[0]) { 545 case 't': case 'T': 546 iv *= 1024; 547 case 'g': case 'G': 548 iv *= 1024; 549 case 'm': case 'M': 550 iv *= 1024; 551 case 'k': case 'K': 552 iv *= 1024; 553 case '\0': 554 break; 555 default: 556 return (0); 557 } 558 *data = iv; 559 return (1); 560 } 561 562 /* 563 * Find the next entry after the one which (cp) falls within, return a 564 * pointer to its start or NULL if there are no more. 565 */ 566 static char * 567 kernenv_next(char *cp) 568 { 569 570 if (cp != NULL) { 571 while (*cp != 0) 572 cp++; 573 cp++; 574 if (*cp == 0) 575 cp = NULL; 576 } 577 return (cp); 578 } 579 580 void 581 tunable_int_init(void *data) 582 { 583 struct tunable_int *d = (struct tunable_int *)data; 584 585 TUNABLE_INT_FETCH(d->path, d->var); 586 } 587 588 void 589 tunable_long_init(void *data) 590 { 591 struct tunable_long *d = (struct tunable_long *)data; 592 593 TUNABLE_LONG_FETCH(d->path, d->var); 594 } 595 596 void 597 tunable_ulong_init(void *data) 598 { 599 struct tunable_ulong *d = (struct tunable_ulong *)data; 600 601 TUNABLE_ULONG_FETCH(d->path, d->var); 602 } 603 604 void 605 tunable_quad_init(void *data) 606 { 607 struct tunable_quad *d = (struct tunable_quad *)data; 608 609 TUNABLE_QUAD_FETCH(d->path, d->var); 610 } 611 612 void 613 tunable_str_init(void *data) 614 { 615 struct tunable_str *d = (struct tunable_str *)data; 616 617 TUNABLE_STR_FETCH(d->path, d->var, d->size); 618 } 619