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 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; 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 len = 0; 103 /* Return the size if called with a NULL buffer */ 104 if (uap->value == NULL) { 105 sx_slock(&kenv_lock); 106 for (i = 0; kenvp[i] != NULL; i++) 107 len += strlen(kenvp[i]) + 1; 108 sx_sunlock(&kenv_lock); 109 td->td_retval[0] = len; 110 return (0); 111 } 112 done = 0; 113 sx_slock(&kenv_lock); 114 for (i = 0; kenvp[i] != NULL && done < uap->len; i++) { 115 len = min(strlen(kenvp[i]) + 1, uap->len - done); 116 error = copyout(kenvp[i], uap->value + done, 117 len); 118 if (error) { 119 sx_sunlock(&kenv_lock); 120 return (error); 121 } 122 done += len; 123 } 124 sx_sunlock(&kenv_lock); 125 return (0); 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 * sizeof(char *), M_KENV, M_WAITOK | M_ZERO); 212 i = 0; 213 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) { 214 len = strlen(cp) + 1; 215 kenvp[i] = malloc(len, M_KENV, M_WAITOK); 216 strcpy(kenvp[i++], cp); 217 } 218 kenvp[i] = NULL; 219 220 sx_init(&kenv_lock, "kernel environment"); 221 dynamic_kenv = 1; 222 } 223 SYSINIT(kenv, SI_SUB_KMEM, SI_ORDER_ANY, init_dynamic_kenv, NULL); 224 225 void 226 freeenv(char *env) 227 { 228 229 if (dynamic_kenv) 230 free(env, M_KENV); 231 } 232 233 /* 234 * Internal functions for string lookup. 235 */ 236 static char * 237 _getenv_dynamic(const char *name, int *idx) 238 { 239 char *cp; 240 int len, i; 241 242 sx_assert(&kenv_lock, SX_LOCKED); 243 len = strlen(name); 244 for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) { 245 if ((cp[len] == '=') && 246 (strncmp(cp, name, len) == 0)) { 247 if (idx != NULL) 248 *idx = i; 249 return (cp + len + 1); 250 } 251 } 252 return (NULL); 253 } 254 255 static char * 256 _getenv_static(const char *name) 257 { 258 char *cp, *ep; 259 int len; 260 261 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) { 262 for (ep = cp; (*ep != '=') && (*ep != 0); ep++) 263 ; 264 if (*ep != '=') 265 continue; 266 len = ep - cp; 267 ep++; 268 if (!strncmp(name, cp, len) && name[len] == 0) 269 return (ep); 270 } 271 return (NULL); 272 } 273 274 /* 275 * Look up an environment variable by name. 276 * Return a pointer to the string if found. 277 * The pointer has to be freed with freeenv() 278 * after use. 279 */ 280 char * 281 getenv(const char *name) 282 { 283 char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1]; 284 char *ret, *cp; 285 int len; 286 287 if (dynamic_kenv) { 288 sx_slock(&kenv_lock); 289 cp = _getenv_dynamic(name, NULL); 290 if (cp != NULL) { 291 strcpy(buf, cp); 292 sx_sunlock(&kenv_lock); 293 len = strlen(buf) + 1; 294 ret = malloc(len, M_KENV, M_WAITOK); 295 strcpy(ret, buf); 296 } else { 297 sx_sunlock(&kenv_lock); 298 ret = NULL; 299 } 300 } else 301 ret = _getenv_static(name); 302 return (ret); 303 } 304 305 /* 306 * Test if an environment variable is defined. 307 */ 308 int 309 testenv(const char *name) 310 { 311 char *cp; 312 313 if (dynamic_kenv) { 314 sx_slock(&kenv_lock); 315 cp = _getenv_dynamic(name, NULL); 316 sx_sunlock(&kenv_lock); 317 } else 318 cp = _getenv_static(name); 319 if (cp != NULL) 320 return (1); 321 return (0); 322 } 323 324 /* 325 * Set an environment variable by name. 326 */ 327 int 328 setenv(const char *name, const char *value) 329 { 330 char *buf, *cp, *oldenv; 331 int namelen, vallen, i; 332 333 KENV_CHECK; 334 335 namelen = strlen(name) + 1; 336 if (namelen > KENV_MNAMELEN) 337 return (-1); 338 vallen = strlen(value) + 1; 339 if (vallen > KENV_MVALLEN) 340 return (-1); 341 buf = malloc(namelen + vallen, M_KENV, M_WAITOK); 342 sprintf(buf, "%s=%s", name, value); 343 344 sx_xlock(&kenv_lock); 345 cp = _getenv_dynamic(name, &i); 346 if (cp != NULL) { 347 oldenv = kenvp[i]; 348 kenvp[i] = buf; 349 sx_xunlock(&kenv_lock); 350 free(oldenv, M_KENV); 351 } else { 352 /* We add the option if it wasn't found */ 353 for (i = 0; (cp = kenvp[i]) != NULL; i++) 354 ; 355 kenvp[i] = buf; 356 kenvp[i + 1] = NULL; 357 sx_xunlock(&kenv_lock); 358 } 359 return (0); 360 } 361 362 /* 363 * Unset an environment variable string. 364 */ 365 int 366 unsetenv(const char *name) 367 { 368 char *cp, *oldenv; 369 int i, j; 370 371 KENV_CHECK; 372 373 sx_xlock(&kenv_lock); 374 cp = _getenv_dynamic(name, &i); 375 if (cp != NULL) { 376 oldenv = kenvp[i]; 377 for (j = i + 1; kenvp[j] != NULL; j++) 378 kenvp[i++] = kenvp[j]; 379 kenvp[i] = NULL; 380 sx_xunlock(&kenv_lock); 381 free(oldenv, M_KENV); 382 return (0); 383 } 384 sx_xunlock(&kenv_lock); 385 return (-1); 386 } 387 388 /* 389 * Return a string value from an environment variable. 390 */ 391 int 392 getenv_string(const char *name, char *data, int size) 393 { 394 char *tmp; 395 396 tmp = getenv(name); 397 if (tmp != NULL) { 398 strlcpy(data, tmp, size); 399 freeenv(tmp); 400 return (1); 401 } else 402 return (0); 403 } 404 405 /* 406 * Return an integer value from an environment variable. 407 */ 408 int 409 getenv_int(const char *name, int *data) 410 { 411 quad_t tmp; 412 int rval; 413 414 rval = getenv_quad(name, &tmp); 415 if (rval) 416 *data = (int) tmp; 417 return (rval); 418 } 419 420 /* 421 * Return a quad_t value from an environment variable. 422 */ 423 int 424 getenv_quad(const char *name, quad_t *data) 425 { 426 char *value; 427 char *vtp; 428 quad_t iv; 429 430 value = getenv(name); 431 if (value == NULL) 432 return (0); 433 iv = strtoq(value, &vtp, 0); 434 if ((vtp == value) || (*vtp != '\0')) { 435 freeenv(value); 436 return (0); 437 } 438 freeenv(value); 439 *data = iv; 440 return (1); 441 } 442 443 /* 444 * Find the next entry after the one which (cp) falls within, return a 445 * pointer to its start or NULL if there are no more. 446 */ 447 static char * 448 kernenv_next(char *cp) 449 { 450 451 if (cp != NULL) { 452 while (*cp != 0) 453 cp++; 454 cp++; 455 if (*cp == 0) 456 cp = NULL; 457 } 458 return (cp); 459 } 460 461 void 462 tunable_int_init(void *data) 463 { 464 struct tunable_int *d = (struct tunable_int *)data; 465 466 TUNABLE_INT_FETCH(d->path, d->var); 467 } 468 469 void 470 tunable_quad_init(void *data) 471 { 472 struct tunable_quad *d = (struct tunable_quad *)data; 473 474 TUNABLE_QUAD_FETCH(d->path, d->var); 475 } 476 477 void 478 tunable_str_init(void *data) 479 { 480 struct tunable_str *d = (struct tunable_str *)data; 481 482 TUNABLE_STR_FETCH(d->path, d->var, d->size); 483 } 484