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/mac.h> 48 #include <sys/malloc.h> 49 #include <sys/mutex.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 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 char *kernenv_next(char *); 64 65 /* dynamic environment variables */ 66 char **kenvp; 67 struct mtx kenv_lock; 68 69 /* 70 * No need to protect this with a mutex 71 * since SYSINITS are single threaded. 72 */ 73 int dynamic_kenv = 0; 74 75 #define KENV_CHECK if (!dynamic_kenv) \ 76 panic("%s: called before SI_SUB_KMEM", __func__) 77 78 int 79 kenv(td, uap) 80 struct thread *td; 81 struct kenv_args /* { 82 int what; 83 const char *name; 84 char *value; 85 int len; 86 } */ *uap; 87 { 88 char *name, *value, *buffer = NULL; 89 size_t len, done, needed; 90 int error, i; 91 92 KASSERT(dynamic_kenv, ("kenv: dynamic_kenv = 0")); 93 94 error = 0; 95 if (uap->what == KENV_DUMP) { 96 #ifdef MAC 97 error = mac_check_kenv_dump(td->td_ucred); 98 if (error) 99 return (error); 100 #endif 101 done = needed = 0; 102 if (uap->len > 0 && uap->value != NULL) 103 buffer = malloc(uap->len, M_TEMP, M_WAITOK|M_ZERO); 104 mtx_lock(&kenv_lock); 105 for (i = 0; kenvp[i] != NULL; i++) { 106 len = strlen(kenvp[i]) + 1; 107 needed += len; 108 len = min(len, uap->len - done); 109 /* 110 * If called with a NULL or insufficiently large 111 * buffer, just keep computing the required size. 112 */ 113 if (uap->value != NULL && buffer != NULL && len > 0) { 114 bcopy(kenvp[i], buffer + done, len); 115 done += len; 116 } 117 } 118 mtx_unlock(&kenv_lock); 119 if (buffer != NULL) { 120 error = copyout(buffer, uap->value, done); 121 free(buffer, M_TEMP); 122 } 123 td->td_retval[0] = ((done == needed) ? 0 : needed); 124 return (error); 125 } 126 127 if ((uap->what == KENV_SET) || 128 (uap->what == KENV_UNSET)) { 129 error = suser(td); 130 if (error) 131 return (error); 132 } 133 134 name = malloc(KENV_MNAMELEN, M_TEMP, M_WAITOK); 135 136 error = copyinstr(uap->name, name, KENV_MNAMELEN, NULL); 137 if (error) 138 goto done; 139 140 switch (uap->what) { 141 case KENV_GET: 142 #ifdef MAC 143 error = mac_check_kenv_get(td->td_ucred, name); 144 if (error) 145 goto done; 146 #endif 147 value = getenv(name); 148 if (value == NULL) { 149 error = ENOENT; 150 goto done; 151 } 152 len = strlen(value) + 1; 153 if (len > uap->len) 154 len = uap->len; 155 error = copyout(value, uap->value, len); 156 freeenv(value); 157 if (error) 158 goto done; 159 td->td_retval[0] = len; 160 break; 161 case KENV_SET: 162 len = uap->len; 163 if (len < 1) { 164 error = EINVAL; 165 goto done; 166 } 167 if (len > KENV_MVALLEN) 168 len = KENV_MVALLEN; 169 value = malloc(len, M_TEMP, M_WAITOK); 170 error = copyinstr(uap->value, value, len, NULL); 171 if (error) { 172 free(value, M_TEMP); 173 goto done; 174 } 175 #ifdef MAC 176 error = mac_check_kenv_set(td->td_ucred, name, value); 177 if (error == 0) 178 #endif 179 setenv(name, value); 180 free(value, M_TEMP); 181 break; 182 case KENV_UNSET: 183 #ifdef MAC 184 error = mac_check_kenv_unset(td->td_ucred, name); 185 if (error) 186 goto done; 187 #endif 188 error = unsetenv(name); 189 if (error) 190 error = ENOENT; 191 break; 192 default: 193 error = EINVAL; 194 break; 195 } 196 done: 197 free(name, M_TEMP); 198 return (error); 199 } 200 201 /* 202 * Setup the dynamic kernel environment. 203 */ 204 static void 205 init_dynamic_kenv(void *data __unused) 206 { 207 char *cp; 208 int len, i; 209 210 kenvp = malloc((KENV_SIZE + 1) * sizeof(char *), M_KENV, 211 M_WAITOK | M_ZERO); 212 i = 0; 213 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) { 214 len = strlen(cp) + 1; 215 if (i < KENV_SIZE) { 216 kenvp[i] = malloc(len, M_KENV, M_WAITOK); 217 strcpy(kenvp[i++], cp); 218 } else 219 printf( 220 "WARNING: too many kenv strings, ignoring %s\n", 221 cp); 222 } 223 kenvp[i] = NULL; 224 225 mtx_init(&kenv_lock, "kernel environment", NULL, MTX_DEF); 226 dynamic_kenv = 1; 227 } 228 SYSINIT(kenv, SI_SUB_KMEM, SI_ORDER_ANY, init_dynamic_kenv, NULL); 229 230 void 231 freeenv(char *env) 232 { 233 234 if (dynamic_kenv) 235 free(env, M_KENV); 236 } 237 238 /* 239 * Internal functions for string lookup. 240 */ 241 static char * 242 _getenv_dynamic(const char *name, int *idx) 243 { 244 char *cp; 245 int len, i; 246 247 mtx_assert(&kenv_lock, MA_OWNED); 248 len = strlen(name); 249 for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) { 250 if ((strncmp(cp, name, len) == 0) && 251 (cp[len] == '=')) { 252 if (idx != NULL) 253 *idx = i; 254 return (cp + len + 1); 255 } 256 } 257 return (NULL); 258 } 259 260 static char * 261 _getenv_static(const char *name) 262 { 263 char *cp, *ep; 264 int len; 265 266 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) { 267 for (ep = cp; (*ep != '=') && (*ep != 0); ep++) 268 ; 269 if (*ep != '=') 270 continue; 271 len = ep - cp; 272 ep++; 273 if (!strncmp(name, cp, len) && name[len] == 0) 274 return (ep); 275 } 276 return (NULL); 277 } 278 279 /* 280 * Look up an environment variable by name. 281 * Return a pointer to the string if found. 282 * The pointer has to be freed with freeenv() 283 * after use. 284 */ 285 char * 286 getenv(const char *name) 287 { 288 char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1]; 289 char *ret, *cp; 290 int len; 291 292 if (dynamic_kenv) { 293 mtx_lock(&kenv_lock); 294 cp = _getenv_dynamic(name, NULL); 295 if (cp != NULL) { 296 strcpy(buf, cp); 297 mtx_unlock(&kenv_lock); 298 len = strlen(buf) + 1; 299 ret = malloc(len, M_KENV, M_WAITOK); 300 strcpy(ret, buf); 301 } else { 302 mtx_unlock(&kenv_lock); 303 ret = NULL; 304 } 305 } else 306 ret = _getenv_static(name); 307 return (ret); 308 } 309 310 /* 311 * Test if an environment variable is defined. 312 */ 313 int 314 testenv(const char *name) 315 { 316 char *cp; 317 318 if (dynamic_kenv) { 319 mtx_lock(&kenv_lock); 320 cp = _getenv_dynamic(name, NULL); 321 mtx_unlock(&kenv_lock); 322 } else 323 cp = _getenv_static(name); 324 if (cp != NULL) 325 return (1); 326 return (0); 327 } 328 329 /* 330 * Set an environment variable by name. 331 */ 332 int 333 setenv(const char *name, const char *value) 334 { 335 char *buf, *cp, *oldenv; 336 int namelen, vallen, i; 337 338 KENV_CHECK; 339 340 namelen = strlen(name) + 1; 341 if (namelen > KENV_MNAMELEN) 342 return (-1); 343 vallen = strlen(value) + 1; 344 if (vallen > KENV_MVALLEN) 345 return (-1); 346 buf = malloc(namelen + vallen, M_KENV, M_WAITOK); 347 sprintf(buf, "%s=%s", name, value); 348 349 mtx_lock(&kenv_lock); 350 cp = _getenv_dynamic(name, &i); 351 if (cp != NULL) { 352 oldenv = kenvp[i]; 353 kenvp[i] = buf; 354 mtx_unlock(&kenv_lock); 355 free(oldenv, M_KENV); 356 } else { 357 /* We add the option if it wasn't found */ 358 for (i = 0; (cp = kenvp[i]) != NULL; i++) 359 ; 360 361 /* Bounds checking */ 362 if (i < 0 || i >= KENV_SIZE) { 363 free(buf, M_KENV); 364 mtx_unlock(&kenv_lock); 365 return (-1); 366 } 367 368 kenvp[i] = buf; 369 kenvp[i + 1] = NULL; 370 mtx_unlock(&kenv_lock); 371 } 372 return (0); 373 } 374 375 /* 376 * Unset an environment variable string. 377 */ 378 int 379 unsetenv(const char *name) 380 { 381 char *cp, *oldenv; 382 int i, j; 383 384 KENV_CHECK; 385 386 mtx_lock(&kenv_lock); 387 cp = _getenv_dynamic(name, &i); 388 if (cp != NULL) { 389 oldenv = kenvp[i]; 390 for (j = i + 1; kenvp[j] != NULL; j++) 391 kenvp[i++] = kenvp[j]; 392 kenvp[i] = NULL; 393 mtx_unlock(&kenv_lock); 394 free(oldenv, M_KENV); 395 return (0); 396 } 397 mtx_unlock(&kenv_lock); 398 return (-1); 399 } 400 401 /* 402 * Return a string value from an environment variable. 403 */ 404 int 405 getenv_string(const char *name, char *data, int size) 406 { 407 char *tmp; 408 409 tmp = getenv(name); 410 if (tmp != NULL) { 411 strlcpy(data, tmp, size); 412 freeenv(tmp); 413 return (1); 414 } else 415 return (0); 416 } 417 418 /* 419 * Return an integer value from an environment variable. 420 */ 421 int 422 getenv_int(const char *name, int *data) 423 { 424 quad_t tmp; 425 int rval; 426 427 rval = getenv_quad(name, &tmp); 428 if (rval) 429 *data = (int) tmp; 430 return (rval); 431 } 432 433 /* 434 * Return a long value from an environment variable. 435 */ 436 long 437 getenv_long(const char *name, long *data) 438 { 439 quad_t tmp; 440 long rval; 441 442 rval = getenv_quad(name, &tmp); 443 if (rval) 444 *data = (long) tmp; 445 return (rval); 446 } 447 448 /* 449 * Return an unsigned long value from an environment variable. 450 */ 451 unsigned long 452 getenv_ulong(const char *name, unsigned long *data) 453 { 454 quad_t tmp; 455 long rval; 456 457 rval = getenv_quad(name, &tmp); 458 if (rval) 459 *data = (unsigned long) tmp; 460 return (rval); 461 } 462 463 /* 464 * Return a quad_t value from an environment variable. 465 */ 466 int 467 getenv_quad(const char *name, quad_t *data) 468 { 469 char *value; 470 char *vtp; 471 quad_t iv; 472 473 value = getenv(name); 474 if (value == NULL) 475 return (0); 476 iv = strtoq(value, &vtp, 0); 477 if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0')) { 478 freeenv(value); 479 return (0); 480 } 481 switch (vtp[0]) { 482 case 't': case 'T': 483 iv *= 1024; 484 case 'g': case 'G': 485 iv *= 1024; 486 case 'm': case 'M': 487 iv *= 1024; 488 case 'k': case 'K': 489 iv *= 1024; 490 case '\0': 491 break; 492 default: 493 freeenv(value); 494 return (0); 495 } 496 *data = iv; 497 freeenv(value); 498 return (1); 499 } 500 501 /* 502 * Find the next entry after the one which (cp) falls within, return a 503 * pointer to its start or NULL if there are no more. 504 */ 505 static char * 506 kernenv_next(char *cp) 507 { 508 509 if (cp != NULL) { 510 while (*cp != 0) 511 cp++; 512 cp++; 513 if (*cp == 0) 514 cp = NULL; 515 } 516 return (cp); 517 } 518 519 void 520 tunable_int_init(void *data) 521 { 522 struct tunable_int *d = (struct tunable_int *)data; 523 524 TUNABLE_INT_FETCH(d->path, d->var); 525 } 526 527 void 528 tunable_long_init(void *data) 529 { 530 struct tunable_long *d = (struct tunable_long *)data; 531 532 TUNABLE_LONG_FETCH(d->path, d->var); 533 } 534 535 void 536 tunable_ulong_init(void *data) 537 { 538 struct tunable_ulong *d = (struct tunable_ulong *)data; 539 540 TUNABLE_ULONG_FETCH(d->path, d->var); 541 } 542 543 void 544 tunable_str_init(void *data) 545 { 546 struct tunable_str *d = (struct tunable_str *)data; 547 548 TUNABLE_STR_FETCH(d->path, d->var, d->size); 549 } 550