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