kern_environment.c revision 94959
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: head/sys/kern/kern_environment.c 94959 2002-04-17 17:51:10Z mux $ 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 <sys/types.h> 40#include <sys/param.h> 41#include <sys/proc.h> 42#include <sys/queue.h> 43#include <sys/lock.h> 44#include <sys/malloc.h> 45#include <sys/mutex.h> 46#include <sys/kernel.h> 47#include <sys/sx.h> 48#include <sys/systm.h> 49#include <sys/sysent.h> 50#include <sys/sysproto.h> 51#include <sys/libkern.h> 52#include <sys/kenv.h> 53 54MALLOC_DEFINE(M_KENV, "kenv", "kernel environment"); 55 56#define KENV_SIZE 512 /* Maximum number of environment strings */ 57 58/* pointer to the static environment */ 59char *kern_envp; 60static char *kernenv_next(char *); 61 62/* dynamic environment variables */ 63char **kenvp; 64struct sx kenv_lock; 65 66/* 67 * No need to protect this with a mutex 68 * since SYSINITS are single threaded. 69 */ 70int dynamic_kenv = 0; 71 72#define KENV_CHECK if (!dynamic_kenv) \ 73 panic("%s: called before SI_SUB_KMEM", __func__) 74 75int 76kenv(td, uap) 77 struct thread *td; 78 struct kenv_args /* { 79 syscallarg(int) what; 80 syscallarg(const char *) name; 81 syscallarg(char *) value; 82 syscallarg(int) len; 83 } */ *uap; 84{ 85 char *name, *value; 86 size_t len, done; 87 int error, i; 88 89 KASSERT(dynamic_kenv, ("kenv: dynamic_kenv = 0")); 90 91 error = 0; 92 if (SCARG(uap, what) == KENV_DUMP) { 93 len = 0; 94 /* Return the size if called with a NULL buffer */ 95 if (SCARG(uap, value) == NULL) { 96 sx_slock(&kenv_lock); 97 for (i = 0; kenvp[i] != NULL; i++) 98 len += strlen(kenvp[i]) + 1; 99 sx_sunlock(&kenv_lock); 100 td->td_retval[0] = len; 101 return (0); 102 } 103 done = 0; 104 sx_slock(&kenv_lock); 105 for (i = 0; kenvp[i] != NULL && done < SCARG(uap, len); i++) { 106 len = min(strlen(kenvp[i]) + 1, SCARG(uap, len) - done); 107 error = copyout(kenvp[i], SCARG(uap, value) + done, 108 len); 109 if (error) { 110 sx_sunlock(&kenv_lock); 111 return (error); 112 } 113 done += len; 114 } 115 sx_sunlock(&kenv_lock); 116 return (0); 117 } 118 119 if ((SCARG(uap, what) == KENV_SET) || 120 (SCARG(uap, what) == KENV_UNSET)) { 121 error = suser(td); 122 if (error) 123 return (error); 124 } 125 126 name = malloc(KENV_MNAMELEN, M_TEMP, M_WAITOK); 127 128 error = copyinstr(SCARG(uap, name), name, KENV_MNAMELEN, NULL); 129 if (error) 130 goto done; 131 132 switch (SCARG(uap, what)) { 133 case KENV_GET: 134 value = getenv(name); 135 if (value == NULL) { 136 error = ENOENT; 137 goto done; 138 } 139 len = strlen(value) + 1; 140 if (len > SCARG(uap, len)) 141 len = SCARG(uap, len); 142 error = copyout(value, SCARG(uap, value), len); 143 freeenv(value); 144 if (error) 145 goto done; 146 td->td_retval[0] = len; 147 break; 148 case KENV_SET: 149 len = SCARG(uap, len); 150 if (len < 1) { 151 error = EINVAL; 152 goto done; 153 } 154 if (len > KENV_MVALLEN) 155 len = KENV_MVALLEN; 156 value = malloc(len, M_TEMP, M_WAITOK); 157 error = copyinstr(SCARG(uap, value), value, len, NULL); 158 if (error) { 159 free(value, M_TEMP); 160 goto done; 161 } 162 setenv(name, value); 163 free(value, M_TEMP); 164 break; 165 case KENV_UNSET: 166 error = unsetenv(name); 167 if (error) 168 error = ENOENT; 169 break; 170 default: 171 error = EINVAL; 172 break; 173 } 174done: 175 free(name, M_TEMP); 176 return (error); 177} 178 179/* 180 * Setup the dynamic kernel environment. 181 */ 182static void 183init_dynamic_kenv(void *data __unused) 184{ 185 char *cp; 186 int len, i; 187 188 kenvp = malloc(KENV_SIZE * sizeof(char *), M_KENV, M_WAITOK | M_ZERO); 189 i = 0; 190 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) { 191 len = strlen(cp) + 1; 192 kenvp[i] = malloc(len, M_KENV, M_WAITOK); 193 strcpy(kenvp[i++], cp); 194 } 195 kenvp[i] = NULL; 196 197 sx_init(&kenv_lock, "kernel environment"); 198 dynamic_kenv = 1; 199} 200SYSINIT(kenv, SI_SUB_KMEM, SI_ORDER_ANY, init_dynamic_kenv, NULL); 201 202void 203freeenv(char *env) 204{ 205 206 if (dynamic_kenv) 207 free(env, M_KENV); 208} 209 210/* 211 * Internal functions for string lookup. 212 */ 213static char * 214_getenv_dynamic(const char *name, int *idx) 215{ 216 char *cp; 217 int len, i; 218 219 sx_assert(&kenv_lock, SX_LOCKED); 220 len = strlen(name); 221 for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) { 222 if ((cp[len] == '=') && 223 (strncmp(cp, name, len) == 0)) { 224 if (idx != NULL) 225 *idx = i; 226 return (cp + len + 1); 227 } 228 } 229 return (NULL); 230} 231 232static char * 233_getenv_static(const char *name) 234{ 235 char *cp, *ep; 236 int len; 237 238 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) { 239 for (ep = cp; (*ep != '=') && (*ep != 0); ep++) 240 ; 241 len = ep - cp; 242 if (*ep == '=') 243 ep++; 244 if (!strncmp(name, cp, len)) 245 return (ep); 246 } 247 return (NULL); 248} 249 250/* 251 * Look up an environment variable by name. 252 * Return a pointer to the string if found. 253 * The pointer has to be freed with freeenv() 254 * after use. 255 */ 256char * 257getenv(const char *name) 258{ 259 char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1]; 260 char *ret, *cp; 261 int len; 262 263 if (dynamic_kenv) { 264 sx_slock(&kenv_lock); 265 cp = _getenv_dynamic(name, NULL); 266 if (cp != NULL) { 267 strcpy(buf, cp); 268 sx_sunlock(&kenv_lock); 269 len = strlen(buf) + 1; 270 ret = malloc(len, M_KENV, M_WAITOK); 271 strcpy(ret, buf); 272 } else { 273 sx_sunlock(&kenv_lock); 274 ret = NULL; 275 } 276 } else 277 ret = _getenv_static(name); 278 return (ret); 279} 280 281/* 282 * Test if an environment variable is defined. 283 */ 284int 285testenv(const char *name) 286{ 287 char *cp; 288 289 if (dynamic_kenv) { 290 sx_slock(&kenv_lock); 291 cp = _getenv_dynamic(name, NULL); 292 sx_sunlock(&kenv_lock); 293 } else 294 cp = _getenv_static(name); 295 if (cp != NULL) 296 return (1); 297 return (0); 298} 299 300/* 301 * Set an environment variable by name. 302 */ 303int 304setenv(const char *name, const char *value) 305{ 306 char *buf, *cp, *oldenv; 307 int namelen, vallen, i; 308 309 KENV_CHECK; 310 311 namelen = strlen(name) + 1; 312 if (namelen > KENV_MNAMELEN) 313 return (-1); 314 vallen = strlen(value) + 1; 315 if (vallen > KENV_MVALLEN) 316 return (-1); 317 buf = malloc(namelen + vallen, M_KENV, M_WAITOK); 318 sprintf(buf, "%s=%s", name, value); 319 320 sx_xlock(&kenv_lock); 321 cp = _getenv_dynamic(name, &i); 322 if (cp != NULL) { 323 oldenv = kenvp[i]; 324 kenvp[i] = buf; 325 sx_xunlock(&kenv_lock); 326 free(oldenv, M_KENV); 327 } else { 328 /* We add the option if it wasn't found */ 329 for (i = 0; (cp = kenvp[i]) != NULL; i++) 330 ; 331 kenvp[i] = buf; 332 kenvp[i + 1] = NULL; 333 sx_xunlock(&kenv_lock); 334 } 335 return (0); 336} 337 338/* 339 * Unset an environment variable string. 340 */ 341int 342unsetenv(const char *name) 343{ 344 char *cp, *oldenv; 345 int i, j; 346 347 KENV_CHECK; 348 349 sx_xlock(&kenv_lock); 350 cp = _getenv_dynamic(name, &i); 351 if (cp != NULL) { 352 oldenv = kenvp[i]; 353 for (j = i + 1; kenvp[j] != NULL; j++) 354 kenvp[i++] = kenvp[j]; 355 kenvp[i] = NULL; 356 sx_xunlock(&kenv_lock); 357 free(oldenv, M_KENV); 358 return (0); 359 } 360 sx_xunlock(&kenv_lock); 361 return (-1); 362} 363 364/* 365 * Return a string value from an environment variable. 366 */ 367int 368getenv_string(const char *name, char *data, int size) 369{ 370 char *tmp; 371 372 tmp = getenv(name); 373 if (tmp != NULL) { 374 strncpy(data, tmp, size); 375 freeenv(tmp); 376 data[size - 1] = 0; 377 return (1); 378 } else 379 return (0); 380} 381 382/* 383 * Return an integer value from an environment variable. 384 */ 385int 386getenv_int(const char *name, int *data) 387{ 388 quad_t tmp; 389 int rval; 390 391 rval = getenv_quad(name, &tmp); 392 if (rval) { 393 *data = (int) tmp; 394 } 395 return (rval); 396} 397 398/* 399 * Return a quad_t value from an environment variable. 400 */ 401int 402getenv_quad(const char *name, quad_t *data) 403{ 404 char *value; 405 char *vtp; 406 quad_t iv; 407 408 if ((value = getenv(name)) == NULL) 409 return(0); 410 411 iv = strtoq(value, &vtp, 0); 412 if ((vtp == value) || (*vtp != '\0')) { 413 freeenv(value); 414 return(0); 415 } 416 417 freeenv(value); 418 *data = iv; 419 return(1); 420} 421 422/* 423 * Find the next entry after the one which (cp) falls within, return a 424 * pointer to its start or NULL if there are no more. 425 */ 426static char * 427kernenv_next(char *cp) 428{ 429 if (cp != NULL) { 430 while (*cp != 0) 431 cp++; 432 cp++; 433 if (*cp == 0) 434 cp = NULL; 435 } 436 return(cp); 437} 438 439void 440tunable_int_init(void *data) 441{ 442 struct tunable_int *d = (struct tunable_int *)data; 443 444 TUNABLE_INT_FETCH(d->path, d->var); 445} 446 447void 448tunable_quad_init(void *data) 449{ 450 struct tunable_quad *d = (struct tunable_quad *)data; 451 452 TUNABLE_QUAD_FETCH(d->path, d->var); 453} 454 455void 456tunable_str_init(void *data) 457{ 458 struct tunable_str *d = (struct tunable_str *)data; 459 460 TUNABLE_STR_FETCH(d->path, d->var, d->size); 461} 462