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 * $FreeBSD$ 27 */ 28 29 /* 30 * The unified bootloader passes us a pointer to a preserved copy of 31 * bootstrap/kernel environment variables. We convert them to a 32 * dynamic array of strings later when the VM subsystem is up. 33 * 34 * We make these available through the kenv(2) syscall for userland 35 * and through getenv()/freeenv() setenv() unsetenv() testenv() for 36 * the kernel. 37 */ 38 39 #include "opt_mac.h" 40 41 #include <sys/types.h> 42 #include <sys/param.h> 43 #include <sys/proc.h> 44 #include <sys/queue.h> 45 #include <sys/lock.h> 46 #include <sys/mac.h> 47 #include <sys/malloc.h> 48 #include <sys/mutex.h> 49 #include <sys/kernel.h> 50 #include <sys/sx.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 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 sx 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; 89 size_t len, done; 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 len = 0; 102 /* Return the size if called with a NULL buffer */ 103 if (uap->value == NULL) { 104 sx_slock(&kenv_lock); 105 for (i = 0; kenvp[i] != NULL; i++) 106 len += strlen(kenvp[i]) + 1; 107 sx_sunlock(&kenv_lock); 108 td->td_retval[0] = len; 109 return (0); 110 } 111 done = 0; 112 sx_slock(&kenv_lock); 113 for (i = 0; kenvp[i] != NULL && done < uap->len; i++) { 114 len = min(strlen(kenvp[i]) + 1, uap->len - done); 115 error = copyout(kenvp[i], uap->value + done, 116 len); 117 if (error) { 118 sx_sunlock(&kenv_lock); 119 return (error); 120 } 121 done += len; 122 } 123 sx_sunlock(&kenv_lock); 124 return (0); 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, 0); 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, 0); 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 * sizeof(char *), M_KENV, M_ZERO); 211 i = 0; 212 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) { 213 len = strlen(cp) + 1; 214 kenvp[i] = malloc(len, M_KENV, 0); 215 strcpy(kenvp[i++], cp); 216 } 217 kenvp[i] = NULL; 218 219 sx_init(&kenv_lock, "kernel environment"); 220 dynamic_kenv = 1; 221 } 222 SYSINIT(kenv, SI_SUB_KMEM, SI_ORDER_ANY, init_dynamic_kenv, NULL); 223 224 void 225 freeenv(char *env) 226 { 227 228 if (dynamic_kenv) 229 free(env, M_KENV); 230 } 231 232 /* 233 * Internal functions for string lookup. 234 */ 235 static char * 236 _getenv_dynamic(const char *name, int *idx) 237 { 238 char *cp; 239 int len, i; 240 241 sx_assert(&kenv_lock, SX_LOCKED); 242 len = strlen(name); 243 for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) { 244 if ((cp[len] == '=') && 245 (strncmp(cp, name, len) == 0)) { 246 if (idx != NULL) 247 *idx = i; 248 return (cp + len + 1); 249 } 250 } 251 return (NULL); 252 } 253 254 static char * 255 _getenv_static(const char *name) 256 { 257 char *cp, *ep; 258 int len; 259 260 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) { 261 for (ep = cp; (*ep != '=') && (*ep != 0); ep++) 262 ; 263 if (*ep != '=') 264 continue; 265 len = ep - cp; 266 ep++; 267 if (!strncmp(name, cp, len) && name[len] == 0) 268 return (ep); 269 } 270 return (NULL); 271 } 272 273 /* 274 * Look up an environment variable by name. 275 * Return a pointer to the string if found. 276 * The pointer has to be freed with freeenv() 277 * after use. 278 */ 279 char * 280 getenv(const char *name) 281 { 282 char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1]; 283 char *ret, *cp; 284 int len; 285 286 if (dynamic_kenv) { 287 sx_slock(&kenv_lock); 288 cp = _getenv_dynamic(name, NULL); 289 if (cp != NULL) { 290 strcpy(buf, cp); 291 sx_sunlock(&kenv_lock); 292 len = strlen(buf) + 1; 293 ret = malloc(len, M_KENV, 0); 294 strcpy(ret, buf); 295 } else { 296 sx_sunlock(&kenv_lock); 297 ret = NULL; 298 } 299 } else 300 ret = _getenv_static(name); 301 return (ret); 302 } 303 304 /* 305 * Test if an environment variable is defined. 306 */ 307 int 308 testenv(const char *name) 309 { 310 char *cp; 311 312 if (dynamic_kenv) { 313 sx_slock(&kenv_lock); 314 cp = _getenv_dynamic(name, NULL); 315 sx_sunlock(&kenv_lock); 316 } else 317 cp = _getenv_static(name); 318 if (cp != NULL) 319 return (1); 320 return (0); 321 } 322 323 /* 324 * Set an environment variable by name. 325 */ 326 int 327 setenv(const char *name, const char *value) 328 { 329 char *buf, *cp, *oldenv; 330 int namelen, vallen, i; 331 332 KENV_CHECK; 333 334 namelen = strlen(name) + 1; 335 if (namelen > KENV_MNAMELEN) 336 return (-1); 337 vallen = strlen(value) + 1; 338 if (vallen > KENV_MVALLEN) 339 return (-1); 340 buf = malloc(namelen + vallen, M_KENV, 0); 341 sprintf(buf, "%s=%s", name, value); 342 343 sx_xlock(&kenv_lock); 344 cp = _getenv_dynamic(name, &i); 345 if (cp != NULL) { 346 oldenv = kenvp[i]; 347 kenvp[i] = buf; 348 sx_xunlock(&kenv_lock); 349 free(oldenv, M_KENV); 350 } else { 351 /* We add the option if it wasn't found */ 352 for (i = 0; (cp = kenvp[i]) != NULL; i++) 353 ; 354 kenvp[i] = buf; 355 kenvp[i + 1] = NULL; 356 sx_xunlock(&kenv_lock); 357 } 358 return (0); 359 } 360 361 /* 362 * Unset an environment variable string. 363 */ 364 int 365 unsetenv(const char *name) 366 { 367 char *cp, *oldenv; 368 int i, j; 369 370 KENV_CHECK; 371 372 sx_xlock(&kenv_lock); 373 cp = _getenv_dynamic(name, &i); 374 if (cp != NULL) { 375 oldenv = kenvp[i]; 376 for (j = i + 1; kenvp[j] != NULL; j++) 377 kenvp[i++] = kenvp[j]; 378 kenvp[i] = NULL; 379 sx_xunlock(&kenv_lock); 380 free(oldenv, M_KENV); 381 return (0); 382 } 383 sx_xunlock(&kenv_lock); 384 return (-1); 385 } 386 387 /* 388 * Return a string value from an environment variable. 389 */ 390 int 391 getenv_string(const char *name, char *data, int size) 392 { 393 char *tmp; 394 395 tmp = getenv(name); 396 if (tmp != NULL) { 397 strlcpy(data, tmp, size); 398 freeenv(tmp); 399 return (1); 400 } else 401 return (0); 402 } 403 404 /* 405 * Return an integer value from an environment variable. 406 */ 407 int 408 getenv_int(const char *name, int *data) 409 { 410 quad_t tmp; 411 int rval; 412 413 rval = getenv_quad(name, &tmp); 414 if (rval) 415 *data = (int) tmp; 416 return (rval); 417 } 418 419 /* 420 * Return a quad_t value from an environment variable. 421 */ 422 int 423 getenv_quad(const char *name, quad_t *data) 424 { 425 char *value; 426 char *vtp; 427 quad_t iv; 428 429 value = getenv(name); 430 if (value == NULL) 431 return (0); 432 iv = strtoq(value, &vtp, 0); 433 if ((vtp == value) || (*vtp != '\0')) { 434 freeenv(value); 435 return (0); 436 } 437 freeenv(value); 438 *data = iv; 439 return (1); 440 } 441 442 /* 443 * Find the next entry after the one which (cp) falls within, return a 444 * pointer to its start or NULL if there are no more. 445 */ 446 static char * 447 kernenv_next(char *cp) 448 { 449 450 if (cp != NULL) { 451 while (*cp != 0) 452 cp++; 453 cp++; 454 if (*cp == 0) 455 cp = NULL; 456 } 457 return (cp); 458 } 459 460 void 461 tunable_int_init(void *data) 462 { 463 struct tunable_int *d = (struct tunable_int *)data; 464 465 TUNABLE_INT_FETCH(d->path, d->var); 466 } 467 468 void 469 tunable_quad_init(void *data) 470 { 471 struct tunable_quad *d = (struct tunable_quad *)data; 472 473 TUNABLE_QUAD_FETCH(d->path, d->var); 474 } 475 476 void 477 tunable_str_init(void *data) 478 { 479 struct tunable_str *d = (struct tunable_str *)data; 480 481 TUNABLE_STR_FETCH(d->path, d->var, d->size); 482 } 483