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 * sizeof(char *), M_KENV, M_WAITOK | M_ZERO); 209 i = 0; 210 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) { 211 len = strlen(cp) + 1; 212 kenvp[i] = malloc(len, M_KENV, M_WAITOK); 213 strcpy(kenvp[i++], cp); 214 } 215 kenvp[i] = NULL; 216 217 sx_init(&kenv_lock, "kernel environment"); 218 dynamic_kenv = 1; 219 } 220 SYSINIT(kenv, SI_SUB_KMEM, SI_ORDER_ANY, init_dynamic_kenv, NULL); 221 222 void 223 freeenv(char *env) 224 { 225 226 if (dynamic_kenv) 227 free(env, M_KENV); 228 } 229 230 /* 231 * Internal functions for string lookup. 232 */ 233 static char * 234 _getenv_dynamic(const char *name, int *idx) 235 { 236 char *cp; 237 int len, i; 238 239 sx_assert(&kenv_lock, SX_LOCKED); 240 len = strlen(name); 241 for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) { 242 if ((cp[len] == '=') && 243 (strncmp(cp, name, len) == 0)) { 244 if (idx != NULL) 245 *idx = i; 246 return (cp + len + 1); 247 } 248 } 249 return (NULL); 250 } 251 252 static char * 253 _getenv_static(const char *name) 254 { 255 char *cp, *ep; 256 int len; 257 258 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) { 259 for (ep = cp; (*ep != '=') && (*ep != 0); ep++) 260 ; 261 if (*ep != '=') 262 continue; 263 len = ep - cp; 264 ep++; 265 if (!strncmp(name, cp, len) && name[len] == 0) 266 return (ep); 267 } 268 return (NULL); 269 } 270 271 /* 272 * Look up an environment variable by name. 273 * Return a pointer to the string if found. 274 * The pointer has to be freed with freeenv() 275 * after use. 276 */ 277 char * 278 getenv(const char *name) 279 { 280 char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1]; 281 char *ret, *cp; 282 int len; 283 284 if (dynamic_kenv) { 285 sx_slock(&kenv_lock); 286 cp = _getenv_dynamic(name, NULL); 287 if (cp != NULL) { 288 strcpy(buf, cp); 289 sx_sunlock(&kenv_lock); 290 len = strlen(buf) + 1; 291 ret = malloc(len, M_KENV, M_WAITOK); 292 strcpy(ret, buf); 293 } else { 294 sx_sunlock(&kenv_lock); 295 ret = NULL; 296 } 297 } else 298 ret = _getenv_static(name); 299 return (ret); 300 } 301 302 /* 303 * Test if an environment variable is defined. 304 */ 305 int 306 testenv(const char *name) 307 { 308 char *cp; 309 310 if (dynamic_kenv) { 311 sx_slock(&kenv_lock); 312 cp = _getenv_dynamic(name, NULL); 313 sx_sunlock(&kenv_lock); 314 } else 315 cp = _getenv_static(name); 316 if (cp != NULL) 317 return (1); 318 return (0); 319 } 320 321 /* 322 * Set an environment variable by name. 323 */ 324 int 325 setenv(const char *name, const char *value) 326 { 327 char *buf, *cp, *oldenv; 328 int namelen, vallen, i; 329 330 KENV_CHECK; 331 332 namelen = strlen(name) + 1; 333 if (namelen > KENV_MNAMELEN) 334 return (-1); 335 vallen = strlen(value) + 1; 336 if (vallen > KENV_MVALLEN) 337 return (-1); 338 buf = malloc(namelen + vallen, M_KENV, M_WAITOK); 339 sprintf(buf, "%s=%s", name, value); 340 341 sx_xlock(&kenv_lock); 342 cp = _getenv_dynamic(name, &i); 343 if (cp != NULL) { 344 oldenv = kenvp[i]; 345 kenvp[i] = buf; 346 sx_xunlock(&kenv_lock); 347 free(oldenv, M_KENV); 348 } else { 349 /* We add the option if it wasn't found */ 350 for (i = 0; (cp = kenvp[i]) != NULL; i++) 351 ; 352 kenvp[i] = buf; 353 kenvp[i + 1] = NULL; 354 sx_xunlock(&kenv_lock); 355 } 356 return (0); 357 } 358 359 /* 360 * Unset an environment variable string. 361 */ 362 int 363 unsetenv(const char *name) 364 { 365 char *cp, *oldenv; 366 int i, j; 367 368 KENV_CHECK; 369 370 sx_xlock(&kenv_lock); 371 cp = _getenv_dynamic(name, &i); 372 if (cp != NULL) { 373 oldenv = kenvp[i]; 374 for (j = i + 1; kenvp[j] != NULL; j++) 375 kenvp[i++] = kenvp[j]; 376 kenvp[i] = NULL; 377 sx_xunlock(&kenv_lock); 378 free(oldenv, M_KENV); 379 return (0); 380 } 381 sx_xunlock(&kenv_lock); 382 return (-1); 383 } 384 385 /* 386 * Return a string value from an environment variable. 387 */ 388 int 389 getenv_string(const char *name, char *data, int size) 390 { 391 char *tmp; 392 393 tmp = getenv(name); 394 if (tmp != NULL) { 395 strlcpy(data, tmp, size); 396 freeenv(tmp); 397 return (1); 398 } else 399 return (0); 400 } 401 402 /* 403 * Return an integer value from an environment variable. 404 */ 405 int 406 getenv_int(const char *name, int *data) 407 { 408 quad_t tmp; 409 int rval; 410 411 rval = getenv_quad(name, &tmp); 412 if (rval) 413 *data = (int) tmp; 414 return (rval); 415 } 416 417 /* 418 * Return a long value from an environment variable. 419 */ 420 long 421 getenv_long(const char *name, long *data) 422 { 423 quad_t tmp; 424 long rval; 425 426 rval = getenv_quad(name, &tmp); 427 if (rval) 428 *data = (long) tmp; 429 return (rval); 430 } 431 432 /* 433 * Return an unsigned long value from an environment variable. 434 */ 435 unsigned long 436 getenv_ulong(const char *name, unsigned long *data) 437 { 438 quad_t tmp; 439 long rval; 440 441 rval = getenv_quad(name, &tmp); 442 if (rval) 443 *data = (unsigned long) tmp; 444 return (rval); 445 } 446 447 /* 448 * Return a quad_t value from an environment variable. 449 */ 450 int 451 getenv_quad(const char *name, quad_t *data) 452 { 453 char *value; 454 char *vtp; 455 quad_t iv; 456 457 value = getenv(name); 458 if (value == NULL) 459 return (0); 460 iv = strtoq(value, &vtp, 0); 461 if ((vtp == value) || (*vtp != '\0')) { 462 freeenv(value); 463 return (0); 464 } 465 freeenv(value); 466 *data = iv; 467 return (1); 468 } 469 470 /* 471 * Find the next entry after the one which (cp) falls within, return a 472 * pointer to its start or NULL if there are no more. 473 */ 474 static char * 475 kernenv_next(char *cp) 476 { 477 478 if (cp != NULL) { 479 while (*cp != 0) 480 cp++; 481 cp++; 482 if (*cp == 0) 483 cp = NULL; 484 } 485 return (cp); 486 } 487 488 void 489 tunable_int_init(void *data) 490 { 491 struct tunable_int *d = (struct tunable_int *)data; 492 493 TUNABLE_INT_FETCH(d->path, d->var); 494 } 495 496 void 497 tunable_long_init(void *data) 498 { 499 struct tunable_long *d = (struct tunable_long *)data; 500 501 TUNABLE_LONG_FETCH(d->path, d->var); 502 } 503 504 void 505 tunable_ulong_init(void *data) 506 { 507 struct tunable_ulong *d = (struct tunable_ulong *)data; 508 509 TUNABLE_ULONG_FETCH(d->path, d->var); 510 } 511 512 void 513 tunable_str_init(void *data) 514 { 515 struct tunable_str *d = (struct tunable_str *)data; 516 517 TUNABLE_STR_FETCH(d->path, d->var, d->size); 518 } 519