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