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 /* 214 * Populate the initial kernel environment. 215 * 216 * This is called very early in MD startup, either to provide a copy of the 217 * environment obtained from a boot loader, or to provide an empty buffer into 218 * which MD code can store an initial environment using kern_setenv() calls. 219 * 220 * If the global envmode is 1, the environment is initialized from the global 221 * static_env[], regardless of the arguments passed. This implements the env 222 * keyword described in config(5). In this case env_pos is set to env_len, 223 * causing kern_setenv() to return -1 (if len > 0) or panic (if len == 0) until 224 * the dynamic environment is available. The envmode and static_env variables 225 * are defined in env.c which is generated by config(8). 226 * 227 * If len is non-zero, the caller is providing an empty buffer. The caller will 228 * subsequently use kern_setenv() to add up to len bytes of initial environment 229 * before the dynamic environment is available. 230 * 231 * If len is zero, the caller is providing a pre-loaded buffer containing 232 * environment strings. Additional strings cannot be added until the dynamic 233 * environment is available. The memory pointed to must remain stable at least 234 * until sysinit runs init_dynamic_kenv(). If no initial environment is 235 * available from the boot loader, passing a NULL pointer allows the static_env 236 * to be installed if it is configured. 237 */ 238 void 239 init_static_kenv(char *buf, size_t len) 240 { 241 242 if (envmode == 1) { 243 kern_envp = static_env; 244 env_len = len; 245 env_pos = len; 246 } else { 247 kern_envp = buf; 248 env_len = len; 249 env_pos = 0; 250 } 251 } 252 253 /* 254 * Setup the dynamic kernel environment. 255 */ 256 static void 257 init_dynamic_kenv(void *data __unused) 258 { 259 char *cp, *cpnext; 260 size_t len; 261 int i; 262 263 kenvp = malloc((KENV_SIZE + 1) * sizeof(char *), M_KENV, 264 M_WAITOK | M_ZERO); 265 i = 0; 266 if (kern_envp && *kern_envp != '\0') { 267 for (cp = kern_envp; cp != NULL; cp = cpnext) { 268 cpnext = kernenv_next(cp); 269 len = strlen(cp) + 1; 270 if (len > KENV_MNAMELEN + 1 + KENV_MVALLEN + 1) { 271 printf( 272 "WARNING: too long kenv string, ignoring %s\n", 273 cp); 274 continue; 275 } 276 if (i < KENV_SIZE) { 277 kenvp[i] = malloc(len, M_KENV, M_WAITOK); 278 strcpy(kenvp[i++], cp); 279 memset(cp, 0, strlen(cp)); 280 } else 281 printf( 282 "WARNING: too many kenv strings, ignoring %s\n", 283 cp); 284 } 285 } 286 kenvp[i] = NULL; 287 288 mtx_init(&kenv_lock, "kernel environment", NULL, MTX_DEF); 289 dynamic_kenv = 1; 290 } 291 SYSINIT(kenv, SI_SUB_KMEM, SI_ORDER_ANY, init_dynamic_kenv, NULL); 292 293 void 294 freeenv(char *env) 295 { 296 297 if (dynamic_kenv && env != NULL) { 298 memset(env, 0, strlen(env)); 299 free(env, M_KENV); 300 } 301 } 302 303 /* 304 * Internal functions for string lookup. 305 */ 306 static char * 307 _getenv_dynamic(const char *name, int *idx) 308 { 309 char *cp; 310 int len, i; 311 312 mtx_assert(&kenv_lock, MA_OWNED); 313 len = strlen(name); 314 for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) { 315 if ((strncmp(cp, name, len) == 0) && 316 (cp[len] == '=')) { 317 if (idx != NULL) 318 *idx = i; 319 return (cp + len + 1); 320 } 321 } 322 return (NULL); 323 } 324 325 static char * 326 _getenv_static(const char *name) 327 { 328 char *cp, *ep; 329 int len; 330 331 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) { 332 for (ep = cp; (*ep != '=') && (*ep != 0); ep++) 333 ; 334 if (*ep != '=') 335 continue; 336 len = ep - cp; 337 ep++; 338 if (!strncmp(name, cp, len) && name[len] == 0) 339 return (ep); 340 } 341 return (NULL); 342 } 343 344 /* 345 * Look up an environment variable by name. 346 * Return a pointer to the string if found. 347 * The pointer has to be freed with freeenv() 348 * after use. 349 */ 350 char * 351 kern_getenv(const char *name) 352 { 353 char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1]; 354 char *ret; 355 356 if (dynamic_kenv) { 357 if (getenv_string(name, buf, sizeof(buf))) { 358 ret = strdup(buf, M_KENV); 359 } else { 360 ret = NULL; 361 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, 362 "getenv"); 363 } 364 } else 365 ret = _getenv_static(name); 366 return (ret); 367 } 368 369 /* 370 * Test if an environment variable is defined. 371 */ 372 int 373 testenv(const char *name) 374 { 375 char *cp; 376 377 if (dynamic_kenv) { 378 mtx_lock(&kenv_lock); 379 cp = _getenv_dynamic(name, NULL); 380 mtx_unlock(&kenv_lock); 381 } else 382 cp = _getenv_static(name); 383 if (cp != NULL) 384 return (1); 385 return (0); 386 } 387 388 static int 389 setenv_static(const char *name, const char *value) 390 { 391 int len; 392 393 if (env_pos >= env_len) 394 return (-1); 395 396 /* Check space for x=y and two nuls */ 397 len = strlen(name) + strlen(value); 398 if (len + 3 < env_len - env_pos) { 399 len = sprintf(&kern_envp[env_pos], "%s=%s", name, value); 400 env_pos += len+1; 401 kern_envp[env_pos] = '\0'; 402 return (0); 403 } else 404 return (-1); 405 406 } 407 408 /* 409 * Set an environment variable by name. 410 */ 411 int 412 kern_setenv(const char *name, const char *value) 413 { 414 char *buf, *cp, *oldenv; 415 int namelen, vallen, i; 416 417 if (dynamic_kenv == 0 && env_len > 0) 418 return (setenv_static(name, value)); 419 420 KENV_CHECK; 421 422 namelen = strlen(name) + 1; 423 if (namelen > KENV_MNAMELEN + 1) 424 return (-1); 425 vallen = strlen(value) + 1; 426 if (vallen > KENV_MVALLEN + 1) 427 return (-1); 428 buf = malloc(namelen + vallen, M_KENV, M_WAITOK); 429 sprintf(buf, "%s=%s", name, value); 430 431 mtx_lock(&kenv_lock); 432 cp = _getenv_dynamic(name, &i); 433 if (cp != NULL) { 434 oldenv = kenvp[i]; 435 kenvp[i] = buf; 436 mtx_unlock(&kenv_lock); 437 free(oldenv, M_KENV); 438 } else { 439 /* We add the option if it wasn't found */ 440 for (i = 0; (cp = kenvp[i]) != NULL; i++) 441 ; 442 443 /* Bounds checking */ 444 if (i < 0 || i >= KENV_SIZE) { 445 free(buf, M_KENV); 446 mtx_unlock(&kenv_lock); 447 return (-1); 448 } 449 450 kenvp[i] = buf; 451 kenvp[i + 1] = NULL; 452 mtx_unlock(&kenv_lock); 453 } 454 return (0); 455 } 456 457 /* 458 * Unset an environment variable string. 459 */ 460 int 461 kern_unsetenv(const char *name) 462 { 463 char *cp, *oldenv; 464 int i, j; 465 466 KENV_CHECK; 467 468 mtx_lock(&kenv_lock); 469 cp = _getenv_dynamic(name, &i); 470 if (cp != NULL) { 471 oldenv = kenvp[i]; 472 for (j = i + 1; kenvp[j] != NULL; j++) 473 kenvp[i++] = kenvp[j]; 474 kenvp[i] = NULL; 475 mtx_unlock(&kenv_lock); 476 memset(oldenv, 0, strlen(oldenv)); 477 free(oldenv, M_KENV); 478 return (0); 479 } 480 mtx_unlock(&kenv_lock); 481 return (-1); 482 } 483 484 /* 485 * Return a string value from an environment variable. 486 */ 487 int 488 getenv_string(const char *name, char *data, int size) 489 { 490 char *cp; 491 492 if (dynamic_kenv) { 493 mtx_lock(&kenv_lock); 494 cp = _getenv_dynamic(name, NULL); 495 if (cp != NULL) 496 strlcpy(data, cp, size); 497 mtx_unlock(&kenv_lock); 498 } else { 499 cp = _getenv_static(name); 500 if (cp != NULL) 501 strlcpy(data, cp, size); 502 } 503 return (cp != NULL); 504 } 505 506 /* 507 * Return an integer value from an environment variable. 508 */ 509 int 510 getenv_int(const char *name, int *data) 511 { 512 quad_t tmp; 513 int rval; 514 515 rval = getenv_quad(name, &tmp); 516 if (rval) 517 *data = (int) tmp; 518 return (rval); 519 } 520 521 /* 522 * Return an unsigned integer value from an environment variable. 523 */ 524 int 525 getenv_uint(const char *name, unsigned int *data) 526 { 527 quad_t tmp; 528 int rval; 529 530 rval = getenv_quad(name, &tmp); 531 if (rval) 532 *data = (unsigned int) tmp; 533 return (rval); 534 } 535 536 /* 537 * Return a long value from an environment variable. 538 */ 539 int 540 getenv_long(const char *name, long *data) 541 { 542 quad_t tmp; 543 int rval; 544 545 rval = getenv_quad(name, &tmp); 546 if (rval) 547 *data = (long) tmp; 548 return (rval); 549 } 550 551 /* 552 * Return an unsigned long value from an environment variable. 553 */ 554 int 555 getenv_ulong(const char *name, unsigned long *data) 556 { 557 quad_t tmp; 558 int rval; 559 560 rval = getenv_quad(name, &tmp); 561 if (rval) 562 *data = (unsigned long) tmp; 563 return (rval); 564 } 565 566 /* 567 * Return a quad_t value from an environment variable. 568 */ 569 int 570 getenv_quad(const char *name, quad_t *data) 571 { 572 char value[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1]; 573 char *vtp; 574 quad_t iv; 575 576 if (!getenv_string(name, value, sizeof(value))) 577 return (0); 578 iv = strtoq(value, &vtp, 0); 579 if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0')) 580 return (0); 581 switch (vtp[0]) { 582 case 't': case 'T': 583 iv *= 1024; 584 case 'g': case 'G': 585 iv *= 1024; 586 case 'm': case 'M': 587 iv *= 1024; 588 case 'k': case 'K': 589 iv *= 1024; 590 case '\0': 591 break; 592 default: 593 return (0); 594 } 595 *data = iv; 596 return (1); 597 } 598 599 /* 600 * Find the next entry after the one which (cp) falls within, return a 601 * pointer to its start or NULL if there are no more. 602 */ 603 static char * 604 kernenv_next(char *cp) 605 { 606 607 if (cp != NULL) { 608 while (*cp != 0) 609 cp++; 610 cp++; 611 if (*cp == 0) 612 cp = NULL; 613 } 614 return (cp); 615 } 616 617 void 618 tunable_int_init(void *data) 619 { 620 struct tunable_int *d = (struct tunable_int *)data; 621 622 TUNABLE_INT_FETCH(d->path, d->var); 623 } 624 625 void 626 tunable_long_init(void *data) 627 { 628 struct tunable_long *d = (struct tunable_long *)data; 629 630 TUNABLE_LONG_FETCH(d->path, d->var); 631 } 632 633 void 634 tunable_ulong_init(void *data) 635 { 636 struct tunable_ulong *d = (struct tunable_ulong *)data; 637 638 TUNABLE_ULONG_FETCH(d->path, d->var); 639 } 640 641 void 642 tunable_quad_init(void *data) 643 { 644 struct tunable_quad *d = (struct tunable_quad *)data; 645 646 TUNABLE_QUAD_FETCH(d->path, d->var); 647 } 648 649 void 650 tunable_str_init(void *data) 651 { 652 struct tunable_str *d = (struct tunable_str *)data; 653 654 TUNABLE_STR_FETCH(d->path, d->var, d->size); 655 } 656