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 "opt_mac.h" 41 42 #include <sys/types.h> 43 #include <sys/param.h> 44 #include <sys/proc.h> 45 #include <sys/queue.h> 46 #include <sys/lock.h> 47 #include <sys/malloc.h> 48 #include <sys/mutex.h> 49 #include <sys/priv.h> 50 #include <sys/kernel.h> 51 #include <sys/systm.h> 52 #include <sys/sysent.h> 53 #include <sys/sysproto.h> 54 #include <sys/libkern.h> 55 #include <sys/kenv.h> 56 57 #include <security/mac/mac_framework.h> 58 59 static MALLOC_DEFINE(M_KENV, "kenv", "kernel environment"); 60 61 #define KENV_SIZE 512 /* Maximum number of environment strings */ 62 63 /* pointer to the static environment */ 64 char *kern_envp; 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 73 * since SYSINITS are single threaded. 74 */ 75 int dynamic_kenv = 0; 76 77 #define KENV_CHECK if (!dynamic_kenv) \ 78 panic("%s: called before SI_SUB_KMEM", __func__) 79 80 int 81 kenv(td, uap) 82 struct thread *td; 83 struct kenv_args /* { 84 int what; 85 const char *name; 86 char *value; 87 int len; 88 } */ *uap; 89 { 90 char *name, *value, *buffer = NULL; 91 size_t len, done, needed; 92 int error, i; 93 94 KASSERT(dynamic_kenv, ("kenv: dynamic_kenv = 0")); 95 96 error = 0; 97 if (uap->what == KENV_DUMP) { 98 #ifdef MAC 99 error = mac_check_kenv_dump(td->td_ucred); 100 if (error) 101 return (error); 102 #endif 103 done = needed = 0; 104 if (uap->len > 0 && uap->value != NULL) 105 buffer = malloc(uap->len, M_TEMP, M_WAITOK|M_ZERO); 106 mtx_lock(&kenv_lock); 107 for (i = 0; kenvp[i] != NULL; i++) { 108 len = strlen(kenvp[i]) + 1; 109 needed += len; 110 len = min(len, uap->len - done); 111 /* 112 * If called with a NULL or insufficiently large 113 * buffer, just keep computing the required size. 114 */ 115 if (uap->value != NULL && buffer != NULL && len > 0) { 116 bcopy(kenvp[i], buffer + done, len); 117 done += len; 118 } 119 } 120 mtx_unlock(&kenv_lock); 121 if (buffer != NULL) { 122 error = copyout(buffer, uap->value, done); 123 free(buffer, M_TEMP); 124 } 125 td->td_retval[0] = ((done == needed) ? 0 : needed); 126 return (error); 127 } 128 129 switch (uap->what) { 130 case KENV_SET: 131 error = priv_check(td, PRIV_KENV_SET); 132 if (error) 133 return (error); 134 break; 135 136 case KENV_UNSET: 137 error = priv_check(td, PRIV_KENV_UNSET); 138 if (error) 139 return (error); 140 break; 141 } 142 143 name = malloc(KENV_MNAMELEN, M_TEMP, M_WAITOK); 144 145 error = copyinstr(uap->name, name, KENV_MNAMELEN, NULL); 146 if (error) 147 goto done; 148 149 switch (uap->what) { 150 case KENV_GET: 151 #ifdef MAC 152 error = mac_check_kenv_get(td->td_ucred, name); 153 if (error) 154 goto done; 155 #endif 156 value = getenv(name); 157 if (value == NULL) { 158 error = ENOENT; 159 goto done; 160 } 161 len = strlen(value) + 1; 162 if (len > uap->len) 163 len = uap->len; 164 error = copyout(value, uap->value, len); 165 freeenv(value); 166 if (error) 167 goto done; 168 td->td_retval[0] = len; 169 break; 170 case KENV_SET: 171 len = uap->len; 172 if (len < 1) { 173 error = EINVAL; 174 goto done; 175 } 176 if (len > KENV_MVALLEN) 177 len = KENV_MVALLEN; 178 value = malloc(len, M_TEMP, M_WAITOK); 179 error = copyinstr(uap->value, value, len, NULL); 180 if (error) { 181 free(value, M_TEMP); 182 goto done; 183 } 184 #ifdef MAC 185 error = mac_check_kenv_set(td->td_ucred, name, value); 186 if (error == 0) 187 #endif 188 setenv(name, value); 189 free(value, M_TEMP); 190 break; 191 case KENV_UNSET: 192 #ifdef MAC 193 error = mac_check_kenv_unset(td->td_ucred, name); 194 if (error) 195 goto done; 196 #endif 197 error = unsetenv(name); 198 if (error) 199 error = ENOENT; 200 break; 201 default: 202 error = EINVAL; 203 break; 204 } 205 done: 206 free(name, M_TEMP); 207 return (error); 208 } 209 210 /* 211 * Setup the dynamic kernel environment. 212 */ 213 static void 214 init_dynamic_kenv(void *data __unused) 215 { 216 char *cp; 217 int len, i; 218 219 kenvp = malloc((KENV_SIZE + 1) * sizeof(char *), M_KENV, 220 M_WAITOK | M_ZERO); 221 i = 0; 222 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) { 223 len = strlen(cp) + 1; 224 if (i < KENV_SIZE) { 225 kenvp[i] = malloc(len, M_KENV, M_WAITOK); 226 strcpy(kenvp[i++], cp); 227 } else 228 printf( 229 "WARNING: too many kenv strings, ignoring %s\n", 230 cp); 231 } 232 kenvp[i] = NULL; 233 234 mtx_init(&kenv_lock, "kernel environment", NULL, MTX_DEF); 235 dynamic_kenv = 1; 236 } 237 SYSINIT(kenv, SI_SUB_KMEM, SI_ORDER_ANY, init_dynamic_kenv, NULL); 238 239 void 240 freeenv(char *env) 241 { 242 243 if (dynamic_kenv) 244 free(env, M_KENV); 245 } 246 247 /* 248 * Internal functions for string lookup. 249 */ 250 static char * 251 _getenv_dynamic(const char *name, int *idx) 252 { 253 char *cp; 254 int len, i; 255 256 mtx_assert(&kenv_lock, MA_OWNED); 257 len = strlen(name); 258 for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) { 259 if ((strncmp(cp, name, len) == 0) && 260 (cp[len] == '=')) { 261 if (idx != NULL) 262 *idx = i; 263 return (cp + len + 1); 264 } 265 } 266 return (NULL); 267 } 268 269 static char * 270 _getenv_static(const char *name) 271 { 272 char *cp, *ep; 273 int len; 274 275 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) { 276 for (ep = cp; (*ep != '=') && (*ep != 0); ep++) 277 ; 278 if (*ep != '=') 279 continue; 280 len = ep - cp; 281 ep++; 282 if (!strncmp(name, cp, len) && name[len] == 0) 283 return (ep); 284 } 285 return (NULL); 286 } 287 288 /* 289 * Look up an environment variable by name. 290 * Return a pointer to the string if found. 291 * The pointer has to be freed with freeenv() 292 * after use. 293 */ 294 char * 295 getenv(const char *name) 296 { 297 char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1]; 298 char *ret, *cp; 299 int len; 300 301 if (dynamic_kenv) { 302 mtx_lock(&kenv_lock); 303 cp = _getenv_dynamic(name, NULL); 304 if (cp != NULL) { 305 strcpy(buf, cp); 306 mtx_unlock(&kenv_lock); 307 len = strlen(buf) + 1; 308 ret = malloc(len, M_KENV, M_WAITOK); 309 strcpy(ret, buf); 310 } else { 311 mtx_unlock(&kenv_lock); 312 ret = NULL; 313 } 314 } else 315 ret = _getenv_static(name); 316 return (ret); 317 } 318 319 /* 320 * Test if an environment variable is defined. 321 */ 322 int 323 testenv(const char *name) 324 { 325 char *cp; 326 327 if (dynamic_kenv) { 328 mtx_lock(&kenv_lock); 329 cp = _getenv_dynamic(name, NULL); 330 mtx_unlock(&kenv_lock); 331 } else 332 cp = _getenv_static(name); 333 if (cp != NULL) 334 return (1); 335 return (0); 336 } 337 338 /* 339 * Set an environment variable by name. 340 */ 341 int 342 setenv(const char *name, const char *value) 343 { 344 char *buf, *cp, *oldenv; 345 int namelen, vallen, i; 346 347 KENV_CHECK; 348 349 namelen = strlen(name) + 1; 350 if (namelen > KENV_MNAMELEN) 351 return (-1); 352 vallen = strlen(value) + 1; 353 if (vallen > KENV_MVALLEN) 354 return (-1); 355 buf = malloc(namelen + vallen, M_KENV, M_WAITOK); 356 sprintf(buf, "%s=%s", name, value); 357 358 mtx_lock(&kenv_lock); 359 cp = _getenv_dynamic(name, &i); 360 if (cp != NULL) { 361 oldenv = kenvp[i]; 362 kenvp[i] = buf; 363 mtx_unlock(&kenv_lock); 364 free(oldenv, M_KENV); 365 } else { 366 /* We add the option if it wasn't found */ 367 for (i = 0; (cp = kenvp[i]) != NULL; i++) 368 ; 369 370 /* Bounds checking */ 371 if (i < 0 || i >= KENV_SIZE) { 372 free(buf, M_KENV); 373 mtx_unlock(&kenv_lock); 374 return (-1); 375 } 376 377 kenvp[i] = buf; 378 kenvp[i + 1] = NULL; 379 mtx_unlock(&kenv_lock); 380 } 381 return (0); 382 } 383 384 /* 385 * Unset an environment variable string. 386 */ 387 int 388 unsetenv(const char *name) 389 { 390 char *cp, *oldenv; 391 int i, j; 392 393 KENV_CHECK; 394 395 mtx_lock(&kenv_lock); 396 cp = _getenv_dynamic(name, &i); 397 if (cp != NULL) { 398 oldenv = kenvp[i]; 399 for (j = i + 1; kenvp[j] != NULL; j++) 400 kenvp[i++] = kenvp[j]; 401 kenvp[i] = NULL; 402 mtx_unlock(&kenv_lock); 403 free(oldenv, M_KENV); 404 return (0); 405 } 406 mtx_unlock(&kenv_lock); 407 return (-1); 408 } 409 410 /* 411 * Return a string value from an environment variable. 412 */ 413 int 414 getenv_string(const char *name, char *data, int size) 415 { 416 char *tmp; 417 418 tmp = getenv(name); 419 if (tmp != NULL) { 420 strlcpy(data, tmp, size); 421 freeenv(tmp); 422 return (1); 423 } else 424 return (0); 425 } 426 427 /* 428 * Return an integer value from an environment variable. 429 */ 430 int 431 getenv_int(const char *name, int *data) 432 { 433 quad_t tmp; 434 int rval; 435 436 rval = getenv_quad(name, &tmp); 437 if (rval) 438 *data = (int) tmp; 439 return (rval); 440 } 441 442 /* 443 * Return a long value from an environment variable. 444 */ 445 long 446 getenv_long(const char *name, long *data) 447 { 448 quad_t tmp; 449 long rval; 450 451 rval = getenv_quad(name, &tmp); 452 if (rval) 453 *data = (long) tmp; 454 return (rval); 455 } 456 457 /* 458 * Return an unsigned long value from an environment variable. 459 */ 460 unsigned long 461 getenv_ulong(const char *name, unsigned long *data) 462 { 463 quad_t tmp; 464 long rval; 465 466 rval = getenv_quad(name, &tmp); 467 if (rval) 468 *data = (unsigned long) tmp; 469 return (rval); 470 } 471 472 /* 473 * Return a quad_t value from an environment variable. 474 */ 475 int 476 getenv_quad(const char *name, quad_t *data) 477 { 478 char *value; 479 char *vtp; 480 quad_t iv; 481 482 value = getenv(name); 483 if (value == NULL) 484 return (0); 485 iv = strtoq(value, &vtp, 0); 486 if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0')) { 487 freeenv(value); 488 return (0); 489 } 490 switch (vtp[0]) { 491 case 't': case 'T': 492 iv *= 1024; 493 case 'g': case 'G': 494 iv *= 1024; 495 case 'm': case 'M': 496 iv *= 1024; 497 case 'k': case 'K': 498 iv *= 1024; 499 case '\0': 500 break; 501 default: 502 freeenv(value); 503 return (0); 504 } 505 *data = iv; 506 freeenv(value); 507 return (1); 508 } 509 510 /* 511 * Find the next entry after the one which (cp) falls within, return a 512 * pointer to its start or NULL if there are no more. 513 */ 514 static char * 515 kernenv_next(char *cp) 516 { 517 518 if (cp != NULL) { 519 while (*cp != 0) 520 cp++; 521 cp++; 522 if (*cp == 0) 523 cp = NULL; 524 } 525 return (cp); 526 } 527 528 void 529 tunable_int_init(void *data) 530 { 531 struct tunable_int *d = (struct tunable_int *)data; 532 533 TUNABLE_INT_FETCH(d->path, d->var); 534 } 535 536 void 537 tunable_long_init(void *data) 538 { 539 struct tunable_long *d = (struct tunable_long *)data; 540 541 TUNABLE_LONG_FETCH(d->path, d->var); 542 } 543 544 void 545 tunable_ulong_init(void *data) 546 { 547 struct tunable_ulong *d = (struct tunable_ulong *)data; 548 549 TUNABLE_ULONG_FETCH(d->path, d->var); 550 } 551 552 void 553 tunable_str_init(void *data) 554 { 555 struct tunable_str *d = (struct tunable_str *)data; 556 557 TUNABLE_STR_FETCH(d->path, d->var, d->size); 558 } 559