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 kenvp[i] = malloc(len, M_KENV, M_WAITOK); 214 strcpy(kenvp[i++], cp); 215 } 216 kenvp[i] = NULL; 217 218 sx_init(&kenv_lock, "kernel environment"); 219 dynamic_kenv = 1; 220 } 221 SYSINIT(kenv, SI_SUB_KMEM, SI_ORDER_ANY, init_dynamic_kenv, NULL); 222 223 void 224 freeenv(char *env) 225 { 226 227 if (dynamic_kenv) 228 free(env, M_KENV); 229 } 230 231 /* 232 * Internal functions for string lookup. 233 */ 234 static char * 235 _getenv_dynamic(const char *name, int *idx) 236 { 237 char *cp; 238 int len, i; 239 240 sx_assert(&kenv_lock, SX_LOCKED); 241 len = strlen(name); 242 for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) { 243 if ((strncmp(cp, name, len) == 0) && 244 (cp[len] == '=')) { 245 if (idx != NULL) 246 *idx = i; 247 return (cp + len + 1); 248 } 249 } 250 return (NULL); 251 } 252 253 static char * 254 _getenv_static(const char *name) 255 { 256 char *cp, *ep; 257 int len; 258 259 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) { 260 for (ep = cp; (*ep != '=') && (*ep != 0); ep++) 261 ; 262 if (*ep != '=') 263 continue; 264 len = ep - cp; 265 ep++; 266 if (!strncmp(name, cp, len) && name[len] == 0) 267 return (ep); 268 } 269 return (NULL); 270 } 271 272 /* 273 * Look up an environment variable by name. 274 * Return a pointer to the string if found. 275 * The pointer has to be freed with freeenv() 276 * after use. 277 */ 278 char * 279 getenv(const char *name) 280 { 281 char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1]; 282 char *ret, *cp; 283 int len; 284 285 if (dynamic_kenv) { 286 sx_slock(&kenv_lock); 287 cp = _getenv_dynamic(name, NULL); 288 if (cp != NULL) { 289 strcpy(buf, cp); 290 sx_sunlock(&kenv_lock); 291 len = strlen(buf) + 1; 292 ret = malloc(len, M_KENV, M_WAITOK); 293 strcpy(ret, buf); 294 } else { 295 sx_sunlock(&kenv_lock); 296 ret = NULL; 297 } 298 } else 299 ret = _getenv_static(name); 300 return (ret); 301 } 302 303 /* 304 * Test if an environment variable is defined. 305 */ 306 int 307 testenv(const char *name) 308 { 309 char *cp; 310 311 if (dynamic_kenv) { 312 sx_slock(&kenv_lock); 313 cp = _getenv_dynamic(name, NULL); 314 sx_sunlock(&kenv_lock); 315 } else 316 cp = _getenv_static(name); 317 if (cp != NULL) 318 return (1); 319 return (0); 320 } 321 322 /* 323 * Set an environment variable by name. 324 */ 325 int 326 setenv(const char *name, const char *value) 327 { 328 char *buf, *cp, *oldenv; 329 int namelen, vallen, i; 330 331 KENV_CHECK; 332 333 namelen = strlen(name) + 1; 334 if (namelen > KENV_MNAMELEN) 335 return (-1); 336 vallen = strlen(value) + 1; 337 if (vallen > KENV_MVALLEN) 338 return (-1); 339 buf = malloc(namelen + vallen, M_KENV, M_WAITOK); 340 sprintf(buf, "%s=%s", name, value); 341 342 sx_xlock(&kenv_lock); 343 cp = _getenv_dynamic(name, &i); 344 if (cp != NULL) { 345 oldenv = kenvp[i]; 346 kenvp[i] = buf; 347 sx_xunlock(&kenv_lock); 348 free(oldenv, M_KENV); 349 } else { 350 /* We add the option if it wasn't found */ 351 for (i = 0; (cp = kenvp[i]) != NULL; i++) 352 ; 353 354 /* Bounds checking */ 355 if (i < 0 || i >= KENV_SIZE) { 356 free(buf, M_KENV); 357 sx_xunlock(&kenv_lock); 358 return (-1); 359 } 360 361 kenvp[i] = buf; 362 kenvp[i + 1] = NULL; 363 sx_xunlock(&kenv_lock); 364 } 365 return (0); 366 } 367 368 /* 369 * Unset an environment variable string. 370 */ 371 int 372 unsetenv(const char *name) 373 { 374 char *cp, *oldenv; 375 int i, j; 376 377 KENV_CHECK; 378 379 sx_xlock(&kenv_lock); 380 cp = _getenv_dynamic(name, &i); 381 if (cp != NULL) { 382 oldenv = kenvp[i]; 383 for (j = i + 1; kenvp[j] != NULL; j++) 384 kenvp[i++] = kenvp[j]; 385 kenvp[i] = NULL; 386 sx_xunlock(&kenv_lock); 387 free(oldenv, M_KENV); 388 return (0); 389 } 390 sx_xunlock(&kenv_lock); 391 return (-1); 392 } 393 394 /* 395 * Return a string value from an environment variable. 396 */ 397 int 398 getenv_string(const char *name, char *data, int size) 399 { 400 char *tmp; 401 402 tmp = getenv(name); 403 if (tmp != NULL) { 404 strlcpy(data, tmp, size); 405 freeenv(tmp); 406 return (1); 407 } else 408 return (0); 409 } 410 411 /* 412 * Return an integer value from an environment variable. 413 */ 414 int 415 getenv_int(const char *name, int *data) 416 { 417 quad_t tmp; 418 int rval; 419 420 rval = getenv_quad(name, &tmp); 421 if (rval) 422 *data = (int) tmp; 423 return (rval); 424 } 425 426 /* 427 * Return a long value from an environment variable. 428 */ 429 long 430 getenv_long(const char *name, long *data) 431 { 432 quad_t tmp; 433 long rval; 434 435 rval = getenv_quad(name, &tmp); 436 if (rval) 437 *data = (long) tmp; 438 return (rval); 439 } 440 441 /* 442 * Return an unsigned long value from an environment variable. 443 */ 444 unsigned long 445 getenv_ulong(const char *name, unsigned long *data) 446 { 447 quad_t tmp; 448 long rval; 449 450 rval = getenv_quad(name, &tmp); 451 if (rval) 452 *data = (unsigned long) tmp; 453 return (rval); 454 } 455 456 /* 457 * Return a quad_t value from an environment variable. 458 */ 459 int 460 getenv_quad(const char *name, quad_t *data) 461 { 462 char *value; 463 char *vtp; 464 quad_t iv; 465 466 value = getenv(name); 467 if (value == NULL) 468 return (0); 469 iv = strtoq(value, &vtp, 0); 470 if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0')) { 471 freeenv(value); 472 return (0); 473 } 474 switch (vtp[0]) { 475 case 't': case 'T': 476 iv *= 1024; 477 case 'g': case 'G': 478 iv *= 1024; 479 case 'm': case 'M': 480 iv *= 1024; 481 case 'k': case 'K': 482 iv *= 1024; 483 case '\0': 484 break; 485 default: 486 freeenv(value); 487 return (0); 488 } 489 *data = iv; 490 freeenv(value); 491 return (1); 492 } 493 494 /* 495 * Find the next entry after the one which (cp) falls within, return a 496 * pointer to its start or NULL if there are no more. 497 */ 498 static char * 499 kernenv_next(char *cp) 500 { 501 502 if (cp != NULL) { 503 while (*cp != 0) 504 cp++; 505 cp++; 506 if (*cp == 0) 507 cp = NULL; 508 } 509 return (cp); 510 } 511 512 void 513 tunable_int_init(void *data) 514 { 515 struct tunable_int *d = (struct tunable_int *)data; 516 517 TUNABLE_INT_FETCH(d->path, d->var); 518 } 519 520 void 521 tunable_long_init(void *data) 522 { 523 struct tunable_long *d = (struct tunable_long *)data; 524 525 TUNABLE_LONG_FETCH(d->path, d->var); 526 } 527 528 void 529 tunable_ulong_init(void *data) 530 { 531 struct tunable_ulong *d = (struct tunable_ulong *)data; 532 533 TUNABLE_ULONG_FETCH(d->path, d->var); 534 } 535 536 void 537 tunable_str_init(void *data) 538 { 539 struct tunable_str *d = (struct tunable_str *)data; 540 541 TUNABLE_STR_FETCH(d->path, d->var, d->size); 542 } 543