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 * When a copy of an initial environment is passed in, we start by scanning that 221 * env for overrides to the compiled-in envmode and hintmode variables. 222 * 223 * If the global envmode is 1, the environment is initialized from the global 224 * static_env[], regardless of the arguments passed. This implements the env 225 * keyword described in config(5). In this case env_pos is set to env_len, 226 * causing kern_setenv() to return -1 (if len > 0) or panic (if len == 0) until 227 * the dynamic environment is available. The envmode and static_env variables 228 * are defined in env.c which is generated by config(8). 229 * 230 * If len is non-zero, the caller is providing an empty buffer. The caller will 231 * subsequently use kern_setenv() to add up to len bytes of initial environment 232 * before the dynamic environment is available. 233 * 234 * If len is zero, the caller is providing a pre-loaded buffer containing 235 * environment strings. Additional strings cannot be added until the dynamic 236 * environment is available. The memory pointed to must remain stable at least 237 * until sysinit runs init_dynamic_kenv(). If no initial environment is 238 * available from the boot loader, passing a NULL pointer allows the static_env 239 * to be installed if it is configured. 240 */ 241 void 242 init_static_kenv(char *buf, size_t len) 243 { 244 char *cp; 245 246 for (cp = buf; cp != NULL && cp[0] != '\0'; cp += strlen(cp) + 1) { 247 if (strcmp(cp, "static_env.disabled=1") == 0) 248 envmode = 0; 249 if (strcmp(cp, "static_hints.disabled=1") == 0) 250 hintmode = 0; 251 } 252 253 if (envmode == 1) { 254 kern_envp = static_env; 255 env_len = len; 256 env_pos = len; 257 } else { 258 kern_envp = buf; 259 env_len = len; 260 env_pos = 0; 261 } 262 } 263 264 /* 265 * Setup the dynamic kernel environment. 266 */ 267 static void 268 init_dynamic_kenv(void *data __unused) 269 { 270 char *cp, *cpnext; 271 size_t len; 272 int i; 273 274 kenvp = malloc((KENV_SIZE + 1) * sizeof(char *), M_KENV, 275 M_WAITOK | M_ZERO); 276 i = 0; 277 if (kern_envp && *kern_envp != '\0') { 278 for (cp = kern_envp; cp != NULL; cp = cpnext) { 279 cpnext = kernenv_next(cp); 280 len = strlen(cp) + 1; 281 if (len > KENV_MNAMELEN + 1 + KENV_MVALLEN + 1) { 282 printf( 283 "WARNING: too long kenv string, ignoring %s\n", 284 cp); 285 continue; 286 } 287 if (i < KENV_SIZE) { 288 kenvp[i] = malloc(len, M_KENV, M_WAITOK); 289 strcpy(kenvp[i++], cp); 290 memset(cp, 0, strlen(cp)); 291 } else 292 printf( 293 "WARNING: too many kenv strings, ignoring %s\n", 294 cp); 295 } 296 } 297 kenvp[i] = NULL; 298 299 mtx_init(&kenv_lock, "kernel environment", NULL, MTX_DEF); 300 dynamic_kenv = 1; 301 } 302 SYSINIT(kenv, SI_SUB_KMEM, SI_ORDER_ANY, init_dynamic_kenv, NULL); 303 304 void 305 freeenv(char *env) 306 { 307 308 if (dynamic_kenv && env != NULL) { 309 memset(env, 0, strlen(env)); 310 free(env, M_KENV); 311 } 312 } 313 314 /* 315 * Internal functions for string lookup. 316 */ 317 static char * 318 _getenv_dynamic(const char *name, int *idx) 319 { 320 char *cp; 321 int len, i; 322 323 mtx_assert(&kenv_lock, MA_OWNED); 324 len = strlen(name); 325 for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) { 326 if ((strncmp(cp, name, len) == 0) && 327 (cp[len] == '=')) { 328 if (idx != NULL) 329 *idx = i; 330 return (cp + len + 1); 331 } 332 } 333 return (NULL); 334 } 335 336 static char * 337 _getenv_static(const char *name) 338 { 339 char *cp, *ep; 340 int len; 341 342 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) { 343 for (ep = cp; (*ep != '=') && (*ep != 0); ep++) 344 ; 345 if (*ep != '=') 346 continue; 347 len = ep - cp; 348 ep++; 349 if (!strncmp(name, cp, len) && name[len] == 0) 350 return (ep); 351 } 352 return (NULL); 353 } 354 355 /* 356 * Look up an environment variable by name. 357 * Return a pointer to the string if found. 358 * The pointer has to be freed with freeenv() 359 * after use. 360 */ 361 char * 362 kern_getenv(const char *name) 363 { 364 char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1]; 365 char *ret; 366 367 if (dynamic_kenv) { 368 if (getenv_string(name, buf, sizeof(buf))) { 369 ret = strdup(buf, M_KENV); 370 } else { 371 ret = NULL; 372 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, 373 "getenv"); 374 } 375 } else 376 ret = _getenv_static(name); 377 return (ret); 378 } 379 380 /* 381 * Test if an environment variable is defined. 382 */ 383 int 384 testenv(const char *name) 385 { 386 char *cp; 387 388 if (dynamic_kenv) { 389 mtx_lock(&kenv_lock); 390 cp = _getenv_dynamic(name, NULL); 391 mtx_unlock(&kenv_lock); 392 } else 393 cp = _getenv_static(name); 394 if (cp != NULL) 395 return (1); 396 return (0); 397 } 398 399 static int 400 setenv_static(const char *name, const char *value) 401 { 402 int len; 403 404 if (env_pos >= env_len) 405 return (-1); 406 407 /* Check space for x=y and two nuls */ 408 len = strlen(name) + strlen(value); 409 if (len + 3 < env_len - env_pos) { 410 len = sprintf(&kern_envp[env_pos], "%s=%s", name, value); 411 env_pos += len+1; 412 kern_envp[env_pos] = '\0'; 413 return (0); 414 } else 415 return (-1); 416 417 } 418 419 /* 420 * Set an environment variable by name. 421 */ 422 int 423 kern_setenv(const char *name, const char *value) 424 { 425 char *buf, *cp, *oldenv; 426 int namelen, vallen, i; 427 428 if (dynamic_kenv == 0 && env_len > 0) 429 return (setenv_static(name, value)); 430 431 KENV_CHECK; 432 433 namelen = strlen(name) + 1; 434 if (namelen > KENV_MNAMELEN + 1) 435 return (-1); 436 vallen = strlen(value) + 1; 437 if (vallen > KENV_MVALLEN + 1) 438 return (-1); 439 buf = malloc(namelen + vallen, M_KENV, M_WAITOK); 440 sprintf(buf, "%s=%s", name, value); 441 442 mtx_lock(&kenv_lock); 443 cp = _getenv_dynamic(name, &i); 444 if (cp != NULL) { 445 oldenv = kenvp[i]; 446 kenvp[i] = buf; 447 mtx_unlock(&kenv_lock); 448 free(oldenv, M_KENV); 449 } else { 450 /* We add the option if it wasn't found */ 451 for (i = 0; (cp = kenvp[i]) != NULL; i++) 452 ; 453 454 /* Bounds checking */ 455 if (i < 0 || i >= KENV_SIZE) { 456 free(buf, M_KENV); 457 mtx_unlock(&kenv_lock); 458 return (-1); 459 } 460 461 kenvp[i] = buf; 462 kenvp[i + 1] = NULL; 463 mtx_unlock(&kenv_lock); 464 } 465 return (0); 466 } 467 468 /* 469 * Unset an environment variable string. 470 */ 471 int 472 kern_unsetenv(const char *name) 473 { 474 char *cp, *oldenv; 475 int i, j; 476 477 KENV_CHECK; 478 479 mtx_lock(&kenv_lock); 480 cp = _getenv_dynamic(name, &i); 481 if (cp != NULL) { 482 oldenv = kenvp[i]; 483 for (j = i + 1; kenvp[j] != NULL; j++) 484 kenvp[i++] = kenvp[j]; 485 kenvp[i] = NULL; 486 mtx_unlock(&kenv_lock); 487 memset(oldenv, 0, strlen(oldenv)); 488 free(oldenv, M_KENV); 489 return (0); 490 } 491 mtx_unlock(&kenv_lock); 492 return (-1); 493 } 494 495 /* 496 * Return a string value from an environment variable. 497 */ 498 int 499 getenv_string(const char *name, char *data, int size) 500 { 501 char *cp; 502 503 if (dynamic_kenv) { 504 mtx_lock(&kenv_lock); 505 cp = _getenv_dynamic(name, NULL); 506 if (cp != NULL) 507 strlcpy(data, cp, size); 508 mtx_unlock(&kenv_lock); 509 } else { 510 cp = _getenv_static(name); 511 if (cp != NULL) 512 strlcpy(data, cp, size); 513 } 514 return (cp != NULL); 515 } 516 517 /* 518 * Return an integer value from an environment variable. 519 */ 520 int 521 getenv_int(const char *name, int *data) 522 { 523 quad_t tmp; 524 int rval; 525 526 rval = getenv_quad(name, &tmp); 527 if (rval) 528 *data = (int) tmp; 529 return (rval); 530 } 531 532 /* 533 * Return an unsigned integer value from an environment variable. 534 */ 535 int 536 getenv_uint(const char *name, unsigned int *data) 537 { 538 quad_t tmp; 539 int rval; 540 541 rval = getenv_quad(name, &tmp); 542 if (rval) 543 *data = (unsigned int) tmp; 544 return (rval); 545 } 546 547 /* 548 * Return a long value from an environment variable. 549 */ 550 int 551 getenv_long(const char *name, long *data) 552 { 553 quad_t tmp; 554 int rval; 555 556 rval = getenv_quad(name, &tmp); 557 if (rval) 558 *data = (long) tmp; 559 return (rval); 560 } 561 562 /* 563 * Return an unsigned long value from an environment variable. 564 */ 565 int 566 getenv_ulong(const char *name, unsigned long *data) 567 { 568 quad_t tmp; 569 int rval; 570 571 rval = getenv_quad(name, &tmp); 572 if (rval) 573 *data = (unsigned long) tmp; 574 return (rval); 575 } 576 577 /* 578 * Return a quad_t value from an environment variable. 579 */ 580 int 581 getenv_quad(const char *name, quad_t *data) 582 { 583 char value[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1]; 584 char *vtp; 585 quad_t iv; 586 587 if (!getenv_string(name, value, sizeof(value))) 588 return (0); 589 iv = strtoq(value, &vtp, 0); 590 if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0')) 591 return (0); 592 switch (vtp[0]) { 593 case 't': case 'T': 594 iv *= 1024; 595 case 'g': case 'G': 596 iv *= 1024; 597 case 'm': case 'M': 598 iv *= 1024; 599 case 'k': case 'K': 600 iv *= 1024; 601 case '\0': 602 break; 603 default: 604 return (0); 605 } 606 *data = iv; 607 return (1); 608 } 609 610 /* 611 * Find the next entry after the one which (cp) falls within, return a 612 * pointer to its start or NULL if there are no more. 613 */ 614 static char * 615 kernenv_next(char *cp) 616 { 617 618 if (cp != NULL) { 619 while (*cp != 0) 620 cp++; 621 cp++; 622 if (*cp == 0) 623 cp = NULL; 624 } 625 return (cp); 626 } 627 628 void 629 tunable_int_init(void *data) 630 { 631 struct tunable_int *d = (struct tunable_int *)data; 632 633 TUNABLE_INT_FETCH(d->path, d->var); 634 } 635 636 void 637 tunable_long_init(void *data) 638 { 639 struct tunable_long *d = (struct tunable_long *)data; 640 641 TUNABLE_LONG_FETCH(d->path, d->var); 642 } 643 644 void 645 tunable_ulong_init(void *data) 646 { 647 struct tunable_ulong *d = (struct tunable_ulong *)data; 648 649 TUNABLE_ULONG_FETCH(d->path, d->var); 650 } 651 652 void 653 tunable_quad_init(void *data) 654 { 655 struct tunable_quad *d = (struct tunable_quad *)data; 656 657 TUNABLE_QUAD_FETCH(d->path, d->var); 658 } 659 660 void 661 tunable_str_init(void *data) 662 { 663 struct tunable_str *d = (struct tunable_str *)data; 664 665 TUNABLE_STR_FETCH(d->path, d->var, d->size); 666 } 667