1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2000,2001 Peter Wemm <peter@FreeBSD.org> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include <sys/param.h> 33 #include <sys/lock.h> 34 #include <sys/kenv.h> 35 #include <sys/kernel.h> 36 #include <sys/malloc.h> 37 #include <sys/mutex.h> 38 #include <sys/sysctl.h> 39 #include <sys/systm.h> 40 #include <sys/bus.h> 41 42 #define FBACK_MDENV 0 /* MD env (e.g. loader.conf) */ 43 #define FBACK_STENV 1 /* Static env */ 44 #define FBACK_STATIC 2 /* static_hints */ 45 46 /* 47 * We'll use hintenv_merged to indicate that the dynamic environment has been 48 * properly prepared for hint usage. This implies that the dynamic environment 49 * has already been setup (dynamic_kenv) and that we have added any supplied 50 * static_hints to the dynamic environment. 51 */ 52 static bool hintenv_merged; 53 /* Static environment and static hints cannot change, so we'll skip known bad */ 54 static bool stenv_skip; 55 static bool sthints_skip; 56 /* 57 * Access functions for device resources. 58 */ 59 60 static void 61 static_hints_to_env(void *data __unused) 62 { 63 const char *cp; 64 char *line, *eq; 65 int eqidx, i; 66 67 cp = static_hints; 68 while (cp && *cp != '\0') { 69 eq = strchr(cp, '='); 70 if (eq == NULL) 71 /* Bad hint value */ 72 continue; 73 eqidx = eq - cp; 74 75 i = strlen(cp); 76 line = malloc(i + 1, M_TEMP, M_WAITOK); 77 strcpy(line, cp); 78 line[eqidx] = line[i] = '\0'; 79 /* 80 * Before adding a hint to the dynamic environment, check if 81 * another value for said hint has already been added. This is 82 * needed because static environment overrides static hints and 83 * dynamic environment overrides all. 84 */ 85 if (testenv(line) == 0) 86 kern_setenv(line, line + eqidx + 1); 87 free(line, M_TEMP); 88 cp += i + 1; 89 } 90 hintenv_merged = true; 91 } 92 93 /* Any time after dynamic env is setup */ 94 SYSINIT(hintenv, SI_SUB_KMEM + 1, SI_ORDER_SECOND, static_hints_to_env, NULL); 95 96 /* 97 * Checks the environment to see if we even have any hints. If it has no hints, 98 * then res_find can take the hint that there's no point in searching it and 99 * either move on to the next environment or fail early. 100 */ 101 static bool 102 _res_checkenv(char *envp) 103 { 104 char *cp; 105 106 cp = envp; 107 while (cp) { 108 if (strncmp(cp, "hint.", 5) == 0) 109 return (true); 110 while (*cp != '\0') 111 cp++; 112 cp++; 113 if (*cp == '\0') 114 break; 115 } 116 return (false); 117 } 118 119 /* 120 * Evil wildcarding resource string lookup. 121 * This walks the supplied env string table and returns a match. 122 * The start point can be remembered for incremental searches. 123 */ 124 static int 125 res_find(char **hintp_cookie, int *line, int *startln, 126 const char *name, int *unit, const char *resname, const char *value, 127 const char **ret_name, int *ret_namelen, int *ret_unit, 128 const char **ret_resname, int *ret_resnamelen, const char **ret_value) 129 { 130 int fbacklvl = FBACK_MDENV, i = 0, n = 0, namelen; 131 char r_name[32]; 132 int r_unit; 133 char r_resname[32]; 134 char r_value[128]; 135 const char *s, *cp; 136 char *hintp, *p; 137 bool dyn_used = false; 138 139 /* 140 * We are expecting that the caller will pass us a hintp_cookie that 141 * they are tracking. Upon entry, if *hintp_cookie is *not* set, this 142 * indicates to us that we should be figuring out based on the current 143 * environment where to search. This keeps us sane throughout the 144 * entirety of a single search. 145 */ 146 if (*hintp_cookie == NULL) { 147 hintp = NULL; 148 if (hintenv_merged) { 149 /* 150 * static_hints, if it was previously used, has 151 * already been folded in to the environment 152 * by this point. 153 */ 154 mtx_lock(&kenv_lock); 155 cp = kenvp[0]; 156 for (i = 0; cp != NULL; cp = kenvp[++i]) { 157 if (!strncmp(cp, "hint.", 5)) { 158 hintp = kenvp[0]; 159 break; 160 } 161 } 162 mtx_unlock(&kenv_lock); 163 dyn_used = true; 164 } else { 165 /* 166 * We'll have a chance to keep coming back here until 167 * we've actually exhausted all of our possibilities. 168 * We might have chosen the MD/Static env because it 169 * had some kind of hints, but perhaps it didn't have 170 * the hint we are looking for. We don't provide any 171 * fallback when searching the dynamic environment. 172 */ 173 fallback: 174 if (dyn_used || fbacklvl >= FBACK_STATIC) 175 return (ENOENT); 176 177 switch (fbacklvl) { 178 case FBACK_MDENV: 179 fbacklvl++; 180 if (_res_checkenv(md_envp)) { 181 hintp = md_envp; 182 break; 183 } 184 185 /* FALLTHROUGH */ 186 case FBACK_STENV: 187 fbacklvl++; 188 if (!stenv_skip && _res_checkenv(kern_envp)) { 189 hintp = kern_envp; 190 break; 191 } else 192 stenv_skip = true; 193 194 /* FALLTHROUGH */ 195 case FBACK_STATIC: 196 fbacklvl++; 197 /* We'll fallback to static_hints if needed/can */ 198 if (!sthints_skip && 199 _res_checkenv(static_hints)) 200 hintp = static_hints; 201 else 202 sthints_skip = true; 203 204 break; 205 default: 206 return (ENOENT); 207 } 208 } 209 210 if (hintp == NULL) 211 return (ENOENT); 212 *hintp_cookie = hintp; 213 } else { 214 hintp = *hintp_cookie; 215 if (hintenv_merged && hintp == kenvp[0]) 216 dyn_used = true; 217 else 218 /* 219 * If we aren't using the dynamic environment, we need 220 * to run through the proper fallback procedure again. 221 * This is so that we do continuations right if we're 222 * working with *line and *startln. 223 */ 224 goto fallback; 225 } 226 227 if (dyn_used) { 228 mtx_lock(&kenv_lock); 229 i = 0; 230 } 231 232 if (name) 233 namelen = strlen(name); 234 cp = hintp; 235 while (cp) { 236 (*line)++; 237 if (strncmp(cp, "hint.", 5) != 0) 238 goto nexthint; 239 if (name && strncmp(cp + 5, name, namelen) != 0) 240 goto nexthint; 241 n = sscanf(cp + 5, "%32[^.].%d.%32[^=]=%127s", r_name, &r_unit, 242 r_resname, r_value); 243 if (n != 4) { 244 printf("CONFIG: invalid hint '%s'\n", cp); 245 p = strchr(cp, 'h'); 246 *p = 'H'; 247 goto nexthint; 248 } 249 if (startln && *startln >= 0 && *line < *startln) 250 goto nexthint; 251 if (name && strcmp(name, r_name) != 0) 252 goto nexthint; 253 if (unit && *unit != r_unit) 254 goto nexthint; 255 if (resname && strcmp(resname, r_resname) != 0) 256 goto nexthint; 257 if (value && strcmp(value, r_value) != 0) 258 goto nexthint; 259 /* Successfully found a hint matching all criteria */ 260 break; 261 nexthint: 262 if (dyn_used) { 263 cp = kenvp[++i]; 264 if (cp == NULL) 265 break; 266 } else { 267 while (*cp != '\0') 268 cp++; 269 cp++; 270 if (*cp == '\0') { 271 cp = NULL; 272 break; 273 } 274 } 275 } 276 if (dyn_used) 277 mtx_unlock(&kenv_lock); 278 if (cp == NULL) 279 goto fallback; 280 281 s = cp; 282 /* This is a bit of a hack, but at least is reentrant */ 283 /* Note that it returns some !unterminated! strings. */ 284 s = strchr(s, '.') + 1; /* start of device */ 285 if (ret_name) 286 *ret_name = s; 287 s = strchr(s, '.') + 1; /* start of unit */ 288 if (ret_namelen && ret_name) 289 *ret_namelen = s - *ret_name - 1; /* device length */ 290 if (ret_unit) 291 *ret_unit = r_unit; 292 s = strchr(s, '.') + 1; /* start of resname */ 293 if (ret_resname) 294 *ret_resname = s; 295 s = strchr(s, '=') + 1; /* start of value */ 296 if (ret_resnamelen && ret_resname) 297 *ret_resnamelen = s - *ret_resname - 1; /* value len */ 298 if (ret_value) 299 *ret_value = s; 300 if (startln) /* line number for anchor */ 301 *startln = *line + 1; 302 return 0; 303 } 304 305 /* 306 * Search all the data sources for matches to our query. We look for 307 * dynamic hints first as overrides for static or fallback hints. 308 */ 309 static int 310 resource_find(int *line, int *startln, 311 const char *name, int *unit, const char *resname, const char *value, 312 const char **ret_name, int *ret_namelen, int *ret_unit, 313 const char **ret_resname, int *ret_resnamelen, const char **ret_value) 314 { 315 int i; 316 int un; 317 char *hintp; 318 319 *line = 0; 320 hintp = NULL; 321 322 /* Search for exact unit matches first */ 323 i = res_find(&hintp, line, startln, name, unit, resname, value, 324 ret_name, ret_namelen, ret_unit, ret_resname, ret_resnamelen, 325 ret_value); 326 if (i == 0) 327 return 0; 328 if (unit == NULL) 329 return ENOENT; 330 /* If we are still here, search for wildcard matches */ 331 un = -1; 332 i = res_find(&hintp, line, startln, name, &un, resname, value, 333 ret_name, ret_namelen, ret_unit, ret_resname, ret_resnamelen, 334 ret_value); 335 if (i == 0) 336 return 0; 337 return ENOENT; 338 } 339 340 int 341 resource_int_value(const char *name, int unit, const char *resname, int *result) 342 { 343 int error; 344 const char *str; 345 char *op; 346 unsigned long val; 347 int line; 348 349 line = 0; 350 error = resource_find(&line, NULL, name, &unit, resname, NULL, 351 NULL, NULL, NULL, NULL, NULL, &str); 352 if (error) 353 return error; 354 if (*str == '\0') 355 return EFTYPE; 356 val = strtoul(str, &op, 0); 357 if (*op != '\0') 358 return EFTYPE; 359 *result = val; 360 return 0; 361 } 362 363 int 364 resource_long_value(const char *name, int unit, const char *resname, 365 long *result) 366 { 367 int error; 368 const char *str; 369 char *op; 370 unsigned long val; 371 int line; 372 373 line = 0; 374 error = resource_find(&line, NULL, name, &unit, resname, NULL, 375 NULL, NULL, NULL, NULL, NULL, &str); 376 if (error) 377 return error; 378 if (*str == '\0') 379 return EFTYPE; 380 val = strtoul(str, &op, 0); 381 if (*op != '\0') 382 return EFTYPE; 383 *result = val; 384 return 0; 385 } 386 387 int 388 resource_string_value(const char *name, int unit, const char *resname, 389 const char **result) 390 { 391 int error; 392 const char *str; 393 int line; 394 395 line = 0; 396 error = resource_find(&line, NULL, name, &unit, resname, NULL, 397 NULL, NULL, NULL, NULL, NULL, &str); 398 if (error) 399 return error; 400 *result = str; 401 return 0; 402 } 403 404 /* 405 * This is a bit nasty, but allows us to not modify the env strings. 406 */ 407 static const char * 408 resource_string_copy(const char *s, int len) 409 { 410 static char stringbuf[256]; 411 static int offset = 0; 412 const char *ret; 413 414 if (len == 0) 415 len = strlen(s); 416 if (len > 255) 417 return NULL; 418 if ((offset + len + 1) > 255) 419 offset = 0; 420 bcopy(s, &stringbuf[offset], len); 421 stringbuf[offset + len] = '\0'; 422 ret = &stringbuf[offset]; 423 offset += len + 1; 424 return ret; 425 } 426 427 /* 428 * err = resource_find_match(&anchor, &name, &unit, resname, value) 429 * Iteratively fetch a list of devices wired "at" something 430 * res and value are restrictions. eg: "at", "scbus0". 431 * For practical purposes, res = required, value = optional. 432 * *name and *unit are set. 433 * set *anchor to zero before starting. 434 */ 435 int 436 resource_find_match(int *anchor, const char **name, int *unit, 437 const char *resname, const char *value) 438 { 439 const char *found_name; 440 int found_namelen; 441 int found_unit; 442 int ret; 443 int newln; 444 445 newln = *anchor; 446 ret = resource_find(anchor, &newln, NULL, NULL, resname, value, 447 &found_name, &found_namelen, &found_unit, NULL, NULL, NULL); 448 if (ret == 0) { 449 *name = resource_string_copy(found_name, found_namelen); 450 *unit = found_unit; 451 } 452 *anchor = newln; 453 return ret; 454 } 455 456 /* 457 * err = resource_find_dev(&anchor, name, &unit, res, value); 458 * Iterate through a list of devices, returning their unit numbers. 459 * res and value are optional restrictions. eg: "at", "scbus0". 460 * *unit is set to the value. 461 * set *anchor to zero before starting. 462 */ 463 int 464 resource_find_dev(int *anchor, const char *name, int *unit, 465 const char *resname, const char *value) 466 { 467 int found_unit; 468 int newln; 469 int ret; 470 471 newln = *anchor; 472 ret = resource_find(anchor, &newln, name, NULL, resname, value, 473 NULL, NULL, &found_unit, NULL, NULL, NULL); 474 if (ret == 0) { 475 *unit = found_unit; 476 } 477 *anchor = newln; 478 return ret; 479 } 480 481 /* 482 * Check to see if a device is disabled via a disabled hint. 483 */ 484 int 485 resource_disabled(const char *name, int unit) 486 { 487 int error, value; 488 489 error = resource_int_value(name, unit, "disabled", &value); 490 if (error) 491 return (0); 492 return (value); 493 } 494 495 /* 496 * Clear a value associated with a device by removing it from 497 * the kernel environment. This only removes a hint for an 498 * exact unit. 499 */ 500 int 501 resource_unset_value(const char *name, int unit, const char *resname) 502 { 503 char varname[128]; 504 const char *retname, *retvalue; 505 int error, line; 506 size_t len; 507 508 line = 0; 509 error = resource_find(&line, NULL, name, &unit, resname, NULL, 510 &retname, NULL, NULL, NULL, NULL, &retvalue); 511 if (error) 512 return (error); 513 514 retname -= strlen("hint."); 515 len = retvalue - retname - 1; 516 if (len > sizeof(varname) - 1) 517 return (ENAMETOOLONG); 518 memcpy(varname, retname, len); 519 varname[len] = '\0'; 520 return (kern_unsetenv(varname)); 521 } 522