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/kernel.h> 50 #include <sys/systm.h> 51 #include <sys/sysent.h> 52 #include <sys/sysproto.h> 53 #include <sys/libkern.h> 54 #include <sys/kenv.h> 55 56 #include <security/mac/mac_framework.h> 57 58 static MALLOC_DEFINE(M_KENV, "kenv", "kernel environment"); 59 60 #define KENV_SIZE 512 /* Maximum number of environment strings */ 61 62 /* pointer to the static environment */ 63 char *kern_envp; 64 static char *kernenv_next(char *); 65 66 /* dynamic environment variables */ 67 char **kenvp; 68 struct mtx kenv_lock; 69 70 /* 71 * No need to protect this with a mutex 72 * 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 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; 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_check_kenv_dump(td->td_ucred); 99 if (error) 100 return (error); 101 #endif 102 done = needed = 0; 103 if (uap->len > 0 && uap->value != NULL) 104 buffer = malloc(uap->len, M_TEMP, M_WAITOK|M_ZERO); 105 mtx_lock(&kenv_lock); 106 for (i = 0; kenvp[i] != NULL; i++) { 107 len = strlen(kenvp[i]) + 1; 108 needed += len; 109 len = min(len, uap->len - done); 110 /* 111 * If called with a NULL or insufficiently large 112 * buffer, just keep computing the required size. 113 */ 114 if (uap->value != NULL && buffer != NULL && len > 0) { 115 bcopy(kenvp[i], buffer + done, len); 116 done += len; 117 } 118 } 119 mtx_unlock(&kenv_lock); 120 if (buffer != NULL) { 121 error = copyout(buffer, uap->value, done); 122 free(buffer, M_TEMP); 123 } 124 td->td_retval[0] = ((done == needed) ? 0 : needed); 125 return (error); 126 } 127 128 if ((uap->what == KENV_SET) || 129 (uap->what == KENV_UNSET)) { 130 error = suser(td); 131 if (error) 132 return (error); 133 } 134 135 name = malloc(KENV_MNAMELEN, M_TEMP, M_WAITOK); 136 137 error = copyinstr(uap->name, name, KENV_MNAMELEN, NULL); 138 if (error) 139 goto done; 140 141 switch (uap->what) { 142 case KENV_GET: 143 #ifdef MAC 144 error = mac_check_kenv_get(td->td_ucred, name); 145 if (error) 146 goto done; 147 #endif 148 value = getenv(name); 149 if (value == NULL) { 150 error = ENOENT; 151 goto done; 152 } 153 len = strlen(value) + 1; 154 if (len > uap->len) 155 len = uap->len; 156 error = copyout(value, uap->value, len); 157 freeenv(value); 158 if (error) 159 goto done; 160 td->td_retval[0] = len; 161 break; 162 case KENV_SET: 163 len = uap->len; 164 if (len < 1) { 165 error = EINVAL; 166 goto done; 167 } 168 if (len > KENV_MVALLEN) 169 len = KENV_MVALLEN; 170 value = malloc(len, M_TEMP, M_WAITOK); 171 error = copyinstr(uap->value, value, len, NULL); 172 if (error) { 173 free(value, M_TEMP); 174 goto done; 175 } 176 #ifdef MAC 177 error = mac_check_kenv_set(td->td_ucred, name, value); 178 if (error == 0) 179 #endif 180 setenv(name, value); 181 free(value, M_TEMP); 182 break; 183 case KENV_UNSET: 184 #ifdef MAC 185 error = mac_check_kenv_unset(td->td_ucred, name); 186 if (error) 187 goto done; 188 #endif 189 error = unsetenv(name); 190 if (error) 191 error = ENOENT; 192 break; 193 default: 194 error = EINVAL; 195 break; 196 } 197 done: 198 free(name, M_TEMP); 199 return (error); 200 } 201 202 /* 203 * Setup the dynamic kernel environment. 204 */ 205 static void 206 init_dynamic_kenv(void *data __unused) 207 { 208 char *cp; 209 int len, i; 210 211 kenvp = malloc((KENV_SIZE + 1) * sizeof(char *), M_KENV, 212 M_WAITOK | M_ZERO); 213 i = 0; 214 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) { 215 len = strlen(cp) + 1; 216 if (i < KENV_SIZE) { 217 kenvp[i] = malloc(len, M_KENV, M_WAITOK); 218 strcpy(kenvp[i++], cp); 219 } else 220 printf( 221 "WARNING: too many kenv strings, ignoring %s\n", 222 cp); 223 } 224 kenvp[i] = NULL; 225 226 mtx_init(&kenv_lock, "kernel environment", NULL, MTX_DEF); 227 dynamic_kenv = 1; 228 } 229 SYSINIT(kenv, SI_SUB_KMEM, SI_ORDER_ANY, init_dynamic_kenv, NULL); 230 231 void 232 freeenv(char *env) 233 { 234 235 if (dynamic_kenv) 236 free(env, M_KENV); 237 } 238 239 /* 240 * Internal functions for string lookup. 241 */ 242 static char * 243 _getenv_dynamic(const char *name, int *idx) 244 { 245 char *cp; 246 int len, i; 247 248 mtx_assert(&kenv_lock, MA_OWNED); 249 len = strlen(name); 250 for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) { 251 if ((strncmp(cp, name, len) == 0) && 252 (cp[len] == '=')) { 253 if (idx != NULL) 254 *idx = i; 255 return (cp + len + 1); 256 } 257 } 258 return (NULL); 259 } 260 261 static char * 262 _getenv_static(const char *name) 263 { 264 char *cp, *ep; 265 int len; 266 267 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) { 268 for (ep = cp; (*ep != '=') && (*ep != 0); ep++) 269 ; 270 if (*ep != '=') 271 continue; 272 len = ep - cp; 273 ep++; 274 if (!strncmp(name, cp, len) && name[len] == 0) 275 return (ep); 276 } 277 return (NULL); 278 } 279 280 /* 281 * Look up an environment variable by name. 282 * Return a pointer to the string if found. 283 * The pointer has to be freed with freeenv() 284 * after use. 285 */ 286 char * 287 getenv(const char *name) 288 { 289 char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1]; 290 char *ret, *cp; 291 int len; 292 293 if (dynamic_kenv) { 294 mtx_lock(&kenv_lock); 295 cp = _getenv_dynamic(name, NULL); 296 if (cp != NULL) { 297 strcpy(buf, cp); 298 mtx_unlock(&kenv_lock); 299 len = strlen(buf) + 1; 300 ret = malloc(len, M_KENV, M_WAITOK); 301 strcpy(ret, buf); 302 } else { 303 mtx_unlock(&kenv_lock); 304 ret = NULL; 305 } 306 } else 307 ret = _getenv_static(name); 308 return (ret); 309 } 310 311 /* 312 * Test if an environment variable is defined. 313 */ 314 int 315 testenv(const char *name) 316 { 317 char *cp; 318 319 if (dynamic_kenv) { 320 mtx_lock(&kenv_lock); 321 cp = _getenv_dynamic(name, NULL); 322 mtx_unlock(&kenv_lock); 323 } else 324 cp = _getenv_static(name); 325 if (cp != NULL) 326 return (1); 327 return (0); 328 } 329 330 /* 331 * Set an environment variable by name. 332 */ 333 int 334 setenv(const char *name, const char *value) 335 { 336 char *buf, *cp, *oldenv; 337 int namelen, vallen, i; 338 339 KENV_CHECK; 340 341 namelen = strlen(name) + 1; 342 if (namelen > KENV_MNAMELEN) 343 return (-1); 344 vallen = strlen(value) + 1; 345 if (vallen > KENV_MVALLEN) 346 return (-1); 347 buf = malloc(namelen + vallen, M_KENV, M_WAITOK); 348 sprintf(buf, "%s=%s", name, value); 349 350 mtx_lock(&kenv_lock); 351 cp = _getenv_dynamic(name, &i); 352 if (cp != NULL) { 353 oldenv = kenvp[i]; 354 kenvp[i] = buf; 355 mtx_unlock(&kenv_lock); 356 free(oldenv, M_KENV); 357 } else { 358 /* We add the option if it wasn't found */ 359 for (i = 0; (cp = kenvp[i]) != NULL; i++) 360 ; 361 362 /* Bounds checking */ 363 if (i < 0 || i >= KENV_SIZE) { 364 free(buf, M_KENV); 365 mtx_unlock(&kenv_lock); 366 return (-1); 367 } 368 369 kenvp[i] = buf; 370 kenvp[i + 1] = NULL; 371 mtx_unlock(&kenv_lock); 372 } 373 return (0); 374 } 375 376 /* 377 * Unset an environment variable string. 378 */ 379 int 380 unsetenv(const char *name) 381 { 382 char *cp, *oldenv; 383 int i, j; 384 385 KENV_CHECK; 386 387 mtx_lock(&kenv_lock); 388 cp = _getenv_dynamic(name, &i); 389 if (cp != NULL) { 390 oldenv = kenvp[i]; 391 for (j = i + 1; kenvp[j] != NULL; j++) 392 kenvp[i++] = kenvp[j]; 393 kenvp[i] = NULL; 394 mtx_unlock(&kenv_lock); 395 free(oldenv, M_KENV); 396 return (0); 397 } 398 mtx_unlock(&kenv_lock); 399 return (-1); 400 } 401 402 /* 403 * Return a string value from an environment variable. 404 */ 405 int 406 getenv_string(const char *name, char *data, int size) 407 { 408 char *tmp; 409 410 tmp = getenv(name); 411 if (tmp != NULL) { 412 strlcpy(data, tmp, size); 413 freeenv(tmp); 414 return (1); 415 } else 416 return (0); 417 } 418 419 /* 420 * Return an integer value from an environment variable. 421 */ 422 int 423 getenv_int(const char *name, int *data) 424 { 425 quad_t tmp; 426 int rval; 427 428 rval = getenv_quad(name, &tmp); 429 if (rval) 430 *data = (int) tmp; 431 return (rval); 432 } 433 434 /* 435 * Return a long value from an environment variable. 436 */ 437 long 438 getenv_long(const char *name, long *data) 439 { 440 quad_t tmp; 441 long rval; 442 443 rval = getenv_quad(name, &tmp); 444 if (rval) 445 *data = (long) tmp; 446 return (rval); 447 } 448 449 /* 450 * Return an unsigned long value from an environment variable. 451 */ 452 unsigned long 453 getenv_ulong(const char *name, unsigned long *data) 454 { 455 quad_t tmp; 456 long rval; 457 458 rval = getenv_quad(name, &tmp); 459 if (rval) 460 *data = (unsigned long) tmp; 461 return (rval); 462 } 463 464 /* 465 * Return a quad_t value from an environment variable. 466 */ 467 int 468 getenv_quad(const char *name, quad_t *data) 469 { 470 char *value; 471 char *vtp; 472 quad_t iv; 473 474 value = getenv(name); 475 if (value == NULL) 476 return (0); 477 iv = strtoq(value, &vtp, 0); 478 if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0')) { 479 freeenv(value); 480 return (0); 481 } 482 switch (vtp[0]) { 483 case 't': case 'T': 484 iv *= 1024; 485 case 'g': case 'G': 486 iv *= 1024; 487 case 'm': case 'M': 488 iv *= 1024; 489 case 'k': case 'K': 490 iv *= 1024; 491 case '\0': 492 break; 493 default: 494 freeenv(value); 495 return (0); 496 } 497 *data = iv; 498 freeenv(value); 499 return (1); 500 } 501 502 /* 503 * Find the next entry after the one which (cp) falls within, return a 504 * pointer to its start or NULL if there are no more. 505 */ 506 static char * 507 kernenv_next(char *cp) 508 { 509 510 if (cp != NULL) { 511 while (*cp != 0) 512 cp++; 513 cp++; 514 if (*cp == 0) 515 cp = NULL; 516 } 517 return (cp); 518 } 519 520 void 521 tunable_int_init(void *data) 522 { 523 struct tunable_int *d = (struct tunable_int *)data; 524 525 TUNABLE_INT_FETCH(d->path, d->var); 526 } 527 528 void 529 tunable_long_init(void *data) 530 { 531 struct tunable_long *d = (struct tunable_long *)data; 532 533 TUNABLE_LONG_FETCH(d->path, d->var); 534 } 535 536 void 537 tunable_ulong_init(void *data) 538 { 539 struct tunable_ulong *d = (struct tunable_ulong *)data; 540 541 TUNABLE_ULONG_FETCH(d->path, d->var); 542 } 543 544 void 545 tunable_str_init(void *data) 546 { 547 struct tunable_str *d = (struct tunable_str *)data; 548 549 TUNABLE_STR_FETCH(d->path, d->var, d->size); 550 } 551