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: src/sys/kern/kern_environment.c,v 1.10.2.7 2002/05/07 09:57:16 bde Exp $ 27 * $DragonFly: src/sys/kern/kern_environment.c,v 1.7 2008/07/23 16:39:28 dillon Exp $ 28 */ 29 30 /* 31 * The unified bootloader passes us a pointer to a preserved copy of 32 * bootstrap/kernel environment variables. We convert them to a dynamic array 33 * of strings later when the VM subsystem is up. 34 * We make these available using sysctl for both in-kernel and 35 * out-of-kernel consumers, as well as the k{get,set,unset,free,test}env() 36 * functions for in-kernel consumers. 37 * 38 * Note that the current sysctl infrastructure doesn't allow 39 * dynamic insertion or traversal through handled spaces. Grr. 40 * 41 * TODO: implement a sysctl handler to provide the functionality mentioned 42 * above. 43 */ 44 45 #include <sys/param.h> 46 #include <sys/kernel.h> 47 #include <sys/libkern.h> 48 #include <sys/malloc.h> 49 #include <sys/spinlock.h> 50 #include <sys/spinlock2.h> 51 #include <sys/systm.h> 52 #include <sys/sysctl.h> 53 #include <sys/libkern.h> 54 55 /* exported variables */ 56 char *kern_envp; /* <sys/systm.h> */ 57 58 /* local variables */ 59 char **kenv_dynp; 60 int kenv_isdynamic; 61 struct spinlock kenv_dynlock; 62 63 /* constants */ 64 MALLOC_DEFINE(M_KENV, "kenv", "kernel environment dynamic storage"); 65 #define KENV_DYNMAXNUM 512 66 #define KENV_MAXNAMELEN 128 67 #define KENV_MAXVALLEN 128 68 69 /* local prototypes */ 70 static char *kenv_getstring_dynamic(const char *name, int *idx); 71 static char *kenv_getstring_static(const char *name); 72 static char *kernenv_next(char *cp); 73 74 /* 75 * Look up a string in the dynamic environment array. Must be called with 76 * kenv_dynlock held. 77 */ 78 static char * 79 kenv_getstring_dynamic(const char *name, int *idx) 80 { 81 char *cp; 82 int len, i; 83 84 len = strlen(name); 85 /* note: kunsetenv() never leaves NULL holes in the array */ 86 for (i = 0; (cp = kenv_dynp[i]) != NULL; i++) { 87 if ((strncmp(cp, name, len) == 0) && (cp[len] == '=')) { 88 if (idx != NULL) 89 *idx = i; 90 return(cp + len + 1); 91 } 92 } 93 return(NULL); 94 } 95 96 /* 97 * Look up a string in the static environment array. 98 */ 99 static char * 100 kenv_getstring_static(const char *name) 101 { 102 char *cp, *ep; 103 int len; 104 105 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) { 106 for (ep = cp; (*ep != '=') && (*ep != 0); ep++) 107 ; 108 if (*ep != '=') 109 continue; 110 len = ep - cp; 111 ep++; 112 if (!strncmp(name, cp, len) && name[len] == 0) 113 return(ep); 114 } 115 return(NULL); 116 } 117 118 /* 119 * Look up an environment variable by name. 120 */ 121 char * 122 kgetenv(const char *name) 123 { 124 char buf[KENV_MAXNAMELEN + 1 + KENV_MAXVALLEN + 1]; 125 char *cp, *ret; 126 int len; 127 128 if (kenv_isdynamic) { 129 spin_lock_wr(&kenv_dynlock); 130 cp = kenv_getstring_dynamic(name, NULL); 131 if (cp != NULL) { 132 strcpy(buf, cp); 133 spin_unlock_wr(&kenv_dynlock); 134 len = strlen(buf) + 1; 135 ret = kmalloc(len, M_KENV, M_WAITOK); 136 strcpy(ret, buf); 137 } else { 138 spin_unlock_wr(&kenv_dynlock); 139 ret = NULL; 140 } 141 } else 142 ret = kenv_getstring_static(name); 143 return(ret); 144 } 145 146 /* 147 * Set an environment variable by name. 148 */ 149 int 150 ksetenv(const char *name, const char *value) 151 { 152 char *cp, *buf, *oldenv; 153 int namelen, vallen, i; 154 155 if (kenv_isdynamic) { 156 namelen = strlen(name) + 1; 157 vallen = strlen(value) + 1; 158 if ((namelen > KENV_MAXNAMELEN) || (vallen > KENV_MAXVALLEN)) 159 return(-1); 160 buf = kmalloc(namelen + vallen, M_KENV, M_WAITOK); 161 ksprintf(buf, "%s=%s", name, value); 162 spin_lock_wr(&kenv_dynlock); 163 cp = kenv_getstring_dynamic(name, &i); 164 if (cp != NULL) { 165 /* replace existing environment variable */ 166 oldenv = kenv_dynp[i]; 167 kenv_dynp[i] = buf; 168 spin_unlock_wr(&kenv_dynlock); 169 kfree(oldenv, M_KENV); 170 } else { 171 /* append new environment variable */ 172 for (i = 0; (cp = kenv_dynp[i]) != NULL; i++) 173 ; 174 /* bounds checking */ 175 if (i < 0 || i >= (KENV_DYNMAXNUM - 1)) { 176 kfree(buf, M_KENV); 177 spin_unlock_wr(&kenv_dynlock); 178 return(-1); 179 } 180 kenv_dynp[i] = buf; 181 kenv_dynp[i + 1] = NULL; 182 spin_unlock_wr(&kenv_dynlock); 183 } 184 return(0); 185 } else { 186 kprintf("WARNING: ksetenv: dynamic array not created yet\n"); 187 return(-1); 188 } 189 } 190 191 /* 192 * Unset an environment variable by name. 193 */ 194 int 195 kunsetenv(const char *name) 196 { 197 char *cp, *oldenv; 198 int i, j; 199 200 if (kenv_isdynamic) { 201 spin_lock_wr(&kenv_dynlock); 202 cp = kenv_getstring_dynamic(name, &i); 203 if (cp != NULL) { 204 oldenv = kenv_dynp[i]; 205 /* move all pointers beyond the unset one down 1 step */ 206 for (j = i + 1; kenv_dynp[j] != NULL; j++) 207 kenv_dynp[i++] = kenv_dynp[j]; 208 kenv_dynp[i] = NULL; 209 spin_unlock_wr(&kenv_dynlock); 210 kfree(oldenv, M_KENV); 211 return(0); 212 } 213 spin_unlock_wr(&kenv_dynlock); 214 return(-1); 215 } else { 216 kprintf("WARNING: kunsetenv: dynamic array not created yet\n"); 217 return(-1); 218 } 219 } 220 221 /* 222 * Free an environment variable that has been copied for a consumer. 223 */ 224 void 225 kfreeenv(char *env) 226 { 227 if (kenv_isdynamic) 228 kfree(env, M_KENV); 229 } 230 231 /* 232 * Test if an environment variable is defined. 233 */ 234 int 235 ktestenv(const char *name) 236 { 237 char *cp; 238 239 if (kenv_isdynamic) { 240 spin_lock_wr(&kenv_dynlock); 241 cp = kenv_getstring_dynamic(name, NULL); 242 spin_unlock_wr(&kenv_dynlock); 243 } else 244 cp = kenv_getstring_static(name); 245 if (cp != NULL) 246 return(1); 247 return(0); 248 } 249 250 /* 251 * Return a string value from an environment variable. 252 */ 253 int 254 kgetenv_string(const char *name, char *data, int size) 255 { 256 char *tmp; 257 258 tmp = kgetenv(name); 259 if (tmp != NULL) { 260 strncpy(data, tmp, size); 261 data[size - 1] = 0; 262 kfreeenv(tmp); 263 return (1); 264 } else 265 return (0); 266 } 267 268 /* 269 * Return an integer value from an environment variable. 270 */ 271 int 272 kgetenv_int(const char *name, int *data) 273 { 274 quad_t tmp; 275 int rval; 276 277 rval = kgetenv_quad(name, &tmp); 278 if (rval) 279 *data = (int) tmp; 280 return (rval); 281 } 282 283 /* 284 * Return an unsigned long value from an environment variable. 285 */ 286 int 287 kgetenv_ulong(const char *name, unsigned long *data) 288 { 289 quad_t tmp; 290 int rval; 291 292 rval = kgetenv_quad(name, &tmp); 293 if (rval) 294 *data = (unsigned long) tmp; 295 return (rval); 296 } 297 298 /* 299 * Return a quad_t value from an environment variable. 300 */ 301 int 302 kgetenv_quad(const char *name, quad_t *data) 303 { 304 char* value; 305 char* vtp; 306 quad_t iv; 307 308 if ((value = kgetenv(name)) == NULL) 309 return(0); 310 311 iv = strtoq(value, &vtp, 0); 312 if ((vtp == value) || (*vtp != '\0')) { 313 kfreeenv(value); 314 return(0); 315 } 316 317 *data = iv; 318 kfreeenv(value); 319 return(1); 320 } 321 322 /* 323 * Boottime (static) kernel environment sysctl handler. 324 */ 325 static int 326 sysctl_kenv_boot(SYSCTL_HANDLER_ARGS) 327 { 328 int *name = (int *)arg1; 329 u_int namelen = arg2; 330 char *cp; 331 int i, error; 332 333 if (kern_envp == NULL) 334 return(ENOENT); 335 336 name++; 337 namelen--; 338 339 if (namelen != 1) 340 return(EINVAL); 341 342 cp = kern_envp; 343 for (i = 0; i < name[0]; i++) { 344 cp = kernenv_next(cp); 345 if (cp == NULL) 346 break; 347 } 348 349 if (cp == NULL) 350 return(ENOENT); 351 352 error = SYSCTL_OUT(req, cp, strlen(cp) + 1); 353 return (error); 354 } 355 356 SYSCTL_NODE(_kern, OID_AUTO, environment, CTLFLAG_RD, sysctl_kenv_boot, 357 "boottime (static) kernel environment space"); 358 359 /* 360 * Find the next entry after the one which (cp) falls within, return a 361 * pointer to its start or NULL if there are no more. 362 */ 363 static char * 364 kernenv_next(char *cp) 365 { 366 if (cp != NULL) { 367 while (*cp != 0) 368 cp++; 369 cp++; 370 if (*cp == 0) 371 cp = NULL; 372 } 373 return(cp); 374 } 375 376 /* 377 * TUNABLE_INT init functions. 378 */ 379 void 380 tunable_int_init(void *data) 381 { 382 struct tunable_int *d = (struct tunable_int *)data; 383 384 TUNABLE_INT_FETCH(d->path, d->var); 385 } 386 387 void 388 tunable_quad_init(void *data) 389 { 390 struct tunable_quad *d = (struct tunable_quad *)data; 391 392 TUNABLE_QUAD_FETCH(d->path, d->var); 393 } 394 395 void 396 tunable_str_init(void *data) 397 { 398 struct tunable_str *d = (struct tunable_str *)data; 399 400 TUNABLE_STR_FETCH(d->path, d->var, d->size); 401 } 402 403 /* 404 * Create the dynamic environment array, and copy in the values from the static 405 * environment as passed by the bootloader. 406 */ 407 static void 408 kenv_init(void *dummy) 409 { 410 char *cp; 411 int len, i; 412 413 kenv_dynp = kmalloc(KENV_DYNMAXNUM * sizeof(char *), M_KENV, 414 M_WAITOK | M_ZERO); 415 416 /* copy the static environment to our dynamic environment */ 417 for (i = 0, cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) { 418 len = strlen(cp) + 1; 419 if (i < (KENV_DYNMAXNUM - 1)) { 420 kenv_dynp[i] = kmalloc(len, M_KENV, M_WAITOK); 421 strcpy(kenv_dynp[i++], cp); 422 } else 423 kprintf("WARNING: kenv: exhausted dynamic storage, " 424 "ignoring string %s\n", cp); 425 } 426 kenv_dynp[i] = NULL; 427 428 spin_init(&kenv_dynlock); 429 kenv_isdynamic = 1; 430 } 431 SYSINIT(kenv, SI_BOOT1_POST, SI_ORDER_ANY, kenv_init, NULL); 432