1 /* 2 * Copyright (C) 2007 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include <stdio.h> 18 #include <stdlib.h> 19 #include <unistd.h> 20 #include <string.h> 21 #include <ctype.h> 22 #include <fcntl.h> 23 #include <stdarg.h> 24 #include <dirent.h> 25 #include <limits.h> 26 #include <errno.h> 27 28 #include <cutils/misc.h> 29 #include <cutils/sockets.h> 30 31 #define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_ 32 #include <sys/_system_properties.h> 33 34 #include <sys/socket.h> 35 #include <sys/un.h> 36 #include <sys/select.h> 37 #include <sys/types.h> 38 #include <netinet/in.h> 39 #include <sys/mman.h> 40 #include <sys/atomics.h> 41 #include <private/android_filesystem_config.h> 42 43 #include "property_service.h" 44 #include "init.h" 45 #include "util.h" 46 #include "log.h" 47 48 #define PERSISTENT_PROPERTY_DIR "/data/property" 49 50 static int persistent_properties_loaded = 0; 51 static int property_area_inited = 0; 52 53 static int property_set_fd = -1; 54 55 /* White list of permissions for setting property services. */ 56 struct { 57 const char *prefix; 58 unsigned int uid; 59 unsigned int gid; 60 } property_perms[] = { 61 { "net.rmnet0.", AID_RADIO, 0 }, 62 { "net.gprs.", AID_RADIO, 0 }, 63 { "net.ppp", AID_RADIO, 0 }, 64 { "ril.", AID_RADIO, 0 }, 65 { "gsm.", AID_RADIO, 0 }, 66 { "persist.radio", AID_RADIO, 0 }, 67 { "net.dns", AID_RADIO, 0 }, 68 { "net.", AID_SYSTEM, 0 }, 69 { "dev.", AID_SYSTEM, 0 }, 70 { "runtime.", AID_SYSTEM, 0 }, 71 { "hw.", AID_SYSTEM, 0 }, 72 { "sys.", AID_SYSTEM, 0 }, 73 { "service.", AID_SYSTEM, 0 }, 74 { "wlan.", AID_SYSTEM, 0 }, 75 { "dhcp.", AID_SYSTEM, 0 }, 76 { "dhcp.", AID_DHCP, 0 }, 77 { "vpn.", AID_SYSTEM, 0 }, 78 { "vpn.", AID_VPN, 0 }, 79 { "debug.", AID_SHELL, 0 }, 80 { "log.", AID_SHELL, 0 }, 81 { "service.adb.root", AID_SHELL, 0 }, 82 { "persist.sys.", AID_SYSTEM, 0 }, 83 { "persist.service.", AID_SYSTEM, 0 }, 84 { "persist.security.", AID_SYSTEM, 0 }, 85 { NULL, 0, 0 } 86 }; 87 88 /* 89 * White list of UID that are allowed to start/stop services. 90 * Currently there are no user apps that require. 91 */ 92 struct { 93 const char *service; 94 unsigned int uid; 95 unsigned int gid; 96 } control_perms[] = { 97 { "dumpstate",AID_SHELL, AID_LOG }, 98 {NULL, 0, 0 } 99 }; 100 101 typedef struct { 102 void *data; 103 size_t size; 104 int fd; 105 } workspace; 106 107 static int init_workspace(workspace *w, size_t size) 108 { 109 void *data; 110 int fd; 111 112 /* dev is a tmpfs that we can use to carve a shared workspace 113 * out of, so let's do that... 114 */ 115 fd = open("/dev/__properties__", O_RDWR | O_CREAT, 0600); 116 if (fd < 0) 117 return -1; 118 119 if (ftruncate(fd, size) < 0) 120 goto out; 121 122 data = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); 123 if(data == MAP_FAILED) 124 goto out; 125 126 close(fd); 127 128 fd = open("/dev/__properties__", O_RDONLY); 129 if (fd < 0) 130 return -1; 131 132 unlink("/dev/__properties__"); 133 134 w->data = data; 135 w->size = size; 136 w->fd = fd; 137 return 0; 138 139 out: 140 close(fd); 141 return -1; 142 } 143 144 /* (8 header words + 247 toc words) = 1020 bytes */ 145 /* 1024 bytes header and toc + 247 prop_infos @ 128 bytes = 32640 bytes */ 146 147 #define PA_COUNT_MAX 247 148 #define PA_INFO_START 1024 149 #define PA_SIZE 32768 150 151 static workspace pa_workspace; 152 static prop_info *pa_info_array; 153 154 extern prop_area *__system_property_area__; 155 156 static int init_property_area(void) 157 { 158 prop_area *pa; 159 160 if(pa_info_array) 161 return -1; 162 163 if(init_workspace(&pa_workspace, PA_SIZE)) 164 return -1; 165 166 fcntl(pa_workspace.fd, F_SETFD, FD_CLOEXEC); 167 168 pa_info_array = (void*) (((char*) pa_workspace.data) + PA_INFO_START); 169 170 pa = pa_workspace.data; 171 memset(pa, 0, PA_SIZE); 172 pa->magic = PROP_AREA_MAGIC; 173 pa->version = PROP_AREA_VERSION; 174 175 /* plug into the lib property services */ 176 __system_property_area__ = pa; 177 property_area_inited = 1; 178 return 0; 179 } 180 181 static void update_prop_info(prop_info *pi, const char *value, unsigned len) 182 { 183 pi->serial = pi->serial | 1; 184 memcpy(pi->value, value, len + 1); 185 pi->serial = (len << 24) | ((pi->serial + 1) & 0xffffff); 186 __futex_wake(&pi->serial, INT32_MAX); 187 } 188 189 static int property_write(prop_info *pi, const char *value) 190 { 191 int valuelen = strlen(value); 192 if(valuelen >= PROP_VALUE_MAX) return -1; 193 update_prop_info(pi, value, valuelen); 194 return 0; 195 } 196 197 198 /* 199 * Checks permissions for starting/stoping system services. 200 * AID_SYSTEM and AID_ROOT are always allowed. 201 * 202 * Returns 1 if uid allowed, 0 otherwise. 203 */ 204 static int check_control_perms(const char *name, unsigned int uid, unsigned int gid) { 205 int i; 206 if (uid == AID_SYSTEM || uid == AID_ROOT) 207 return 1; 208 209 /* Search the ACL */ 210 for (i = 0; control_perms[i].service; i++) { 211 if (strcmp(control_perms[i].service, name) == 0) { 212 if ((uid && control_perms[i].uid == uid) || 213 (gid && control_perms[i].gid == gid)) { 214 return 1; 215 } 216 } 217 } 218 return 0; 219 } 220 221 /* 222 * Checks permissions for setting system properties. 223 * Returns 1 if uid allowed, 0 otherwise. 224 */ 225 static int check_perms(const char *name, unsigned int uid, unsigned int gid) 226 { 227 int i; 228 if (uid == 0) 229 return 1; 230 231 if(!strncmp(name, "ro.", 3)) 232 name +=3; 233 234 for (i = 0; property_perms[i].prefix; i++) { 235 int tmp; 236 if (strncmp(property_perms[i].prefix, name, 237 strlen(property_perms[i].prefix)) == 0) { 238 if ((uid && property_perms[i].uid == uid) || 239 (gid && property_perms[i].gid == gid)) { 240 return 1; 241 } 242 } 243 } 244 245 return 0; 246 } 247 248 const char* property_get(const char *name) 249 { 250 prop_info *pi; 251 252 if(strlen(name) >= PROP_NAME_MAX) return 0; 253 254 pi = (prop_info*) __system_property_find(name); 255 256 if(pi != 0) { 257 return pi->value; 258 } else { 259 return 0; 260 } 261 } 262 263 static void write_persistent_property(const char *name, const char *value) 264 { 265 const char *tempPath = PERSISTENT_PROPERTY_DIR "/.temp"; 266 char path[PATH_MAX]; 267 int fd, length; 268 269 snprintf(path, sizeof(path), "%s/%s", PERSISTENT_PROPERTY_DIR, name); 270 271 fd = open(tempPath, O_WRONLY|O_CREAT|O_TRUNC, 0600); 272 if (fd < 0) { 273 ERROR("Unable to write persistent property to temp file %s errno: %d\n", tempPath, errno); 274 return; 275 } 276 write(fd, value, strlen(value)); 277 close(fd); 278 279 if (rename(tempPath, path)) { 280 unlink(tempPath); 281 ERROR("Unable to rename persistent property file %s to %s\n", tempPath, path); 282 } 283 } 284 285 int property_set(const char *name, const char *value) 286 { 287 prop_area *pa; 288 prop_info *pi; 289 290 int namelen = strlen(name); 291 int valuelen = strlen(value); 292 293 if(namelen >= PROP_NAME_MAX) return -1; 294 if(valuelen >= PROP_VALUE_MAX) return -1; 295 if(namelen < 1) return -1; 296 297 pi = (prop_info*) __system_property_find(name); 298 299 if(pi != 0) { 300 /* ro.* properties may NEVER be modified once set */ 301 if(!strncmp(name, "ro.", 3)) return -1; 302 303 pa = __system_property_area__; 304 update_prop_info(pi, value, valuelen); 305 pa->serial++; 306 __futex_wake(&pa->serial, INT32_MAX); 307 } else { 308 pa = __system_property_area__; 309 if(pa->count == PA_COUNT_MAX) return -1; 310 311 pi = pa_info_array + pa->count; 312 pi->serial = (valuelen << 24); 313 memcpy(pi->name, name, namelen + 1); 314 memcpy(pi->value, value, valuelen + 1); 315 316 pa->toc[pa->count] = 317 (namelen << 24) | (((unsigned) pi) - ((unsigned) pa)); 318 319 pa->count++; 320 pa->serial++; 321 __futex_wake(&pa->serial, INT32_MAX); 322 } 323 /* If name starts with "net." treat as a DNS property. */ 324 if (strncmp("net.", name, strlen("net.")) == 0) { 325 if (strcmp("net.change", name) == 0) { 326 return 0; 327 } 328 /* 329 * The 'net.change' property is a special property used track when any 330 * 'net.*' property name is updated. It is _ONLY_ updated here. Its value 331 * contains the last updated 'net.*' property. 332 */ 333 property_set("net.change", name); 334 } else if (persistent_properties_loaded && 335 strncmp("persist.", name, strlen("persist.")) == 0) { 336 /* 337 * Don't write properties to disk until after we have read all default properties 338 * to prevent them from being overwritten by default values. 339 */ 340 write_persistent_property(name, value); 341 } 342 property_changed(name, value); 343 return 0; 344 } 345 346 static int property_list(void (*propfn)(const char *key, const char *value, void *cookie), 347 void *cookie) 348 { 349 char name[PROP_NAME_MAX]; 350 char value[PROP_VALUE_MAX]; 351 const prop_info *pi; 352 unsigned n; 353 354 for(n = 0; (pi = __system_property_find_nth(n)); n++) { 355 __system_property_read(pi, name, value); 356 propfn(name, value, cookie); 357 } 358 return 0; 359 } 360 361 void handle_property_set_fd() 362 { 363 prop_msg msg; 364 int s; 365 int r; 366 int res; 367 struct ucred cr; 368 struct sockaddr_un addr; 369 socklen_t addr_size = sizeof(addr); 370 socklen_t cr_size = sizeof(cr); 371 372 if ((s = accept(property_set_fd, (struct sockaddr *) &addr, &addr_size)) < 0) { 373 return; 374 } 375 376 /* Check socket options here */ 377 if (getsockopt(s, SOL_SOCKET, SO_PEERCRED, &cr, &cr_size) < 0) { 378 close(s); 379 ERROR("Unable to recieve socket options\n"); 380 return; 381 } 382 383 r = recv(s, &msg, sizeof(msg), 0); 384 close(s); 385 if(r != sizeof(prop_msg)) { 386 ERROR("sys_prop: mis-match msg size recieved: %d expected: %d\n", 387 r, sizeof(prop_msg)); 388 return; 389 } 390 391 switch(msg.cmd) { 392 case PROP_MSG_SETPROP: 393 msg.name[PROP_NAME_MAX-1] = 0; 394 msg.value[PROP_VALUE_MAX-1] = 0; 395 396 if(memcmp(msg.name,"ctl.",4) == 0) { 397 if (check_control_perms(msg.value, cr.uid, cr.gid)) { 398 handle_control_message((char*) msg.name + 4, (char*) msg.value); 399 } else { 400 ERROR("sys_prop: Unable to %s service ctl [%s] uid: %d pid:%d\n", 401 msg.name + 4, msg.value, cr.uid, cr.pid); 402 } 403 } else { 404 if (check_perms(msg.name, cr.uid, cr.gid)) { 405 property_set((char*) msg.name, (char*) msg.value); 406 } else { 407 ERROR("sys_prop: permission denied uid:%d name:%s\n", 408 cr.uid, msg.name); 409 } 410 } 411 break; 412 413 default: 414 break; 415 } 416 } 417 418 void get_property_workspace(int *fd, int *sz) 419 { 420 *fd = pa_workspace.fd; 421 *sz = pa_workspace.size; 422 } 423 424 static void load_properties(char *data) 425 { 426 char *key, *value, *eol, *sol, *tmp; 427 428 sol = data; 429 while((eol = strchr(sol, '\n'))) { 430 key = sol; 431 *eol++ = 0; 432 sol = eol; 433 434 value = strchr(key, '='); 435 if(value == 0) continue; 436 *value++ = 0; 437 438 while(isspace(*key)) key++; 439 if(*key == '#') continue; 440 tmp = value - 2; 441 while((tmp > key) && isspace(*tmp)) *tmp-- = 0; 442 443 while(isspace(*value)) value++; 444 tmp = eol - 2; 445 while((tmp > value) && isspace(*tmp)) *tmp-- = 0; 446 447 property_set(key, value); 448 } 449 } 450 451 static void load_properties_from_file(const char *fn) 452 { 453 char *data; 454 unsigned sz; 455 456 data = read_file(fn, &sz); 457 458 if(data != 0) { 459 load_properties(data); 460 free(data); 461 } 462 } 463 464 static void load_persistent_properties() 465 { 466 DIR* dir = opendir(PERSISTENT_PROPERTY_DIR); 467 struct dirent* entry; 468 char path[PATH_MAX]; 469 char value[PROP_VALUE_MAX]; 470 int fd, length; 471 472 if (dir) { 473 while ((entry = readdir(dir)) != NULL) { 474 if (strncmp("persist.", entry->d_name, strlen("persist."))) 475 continue; 476 #if HAVE_DIRENT_D_TYPE 477 if (entry->d_type != DT_REG) 478 continue; 479 #endif 480 /* open the file and read the property value */ 481 snprintf(path, sizeof(path), "%s/%s", PERSISTENT_PROPERTY_DIR, entry->d_name); 482 fd = open(path, O_RDONLY); 483 if (fd >= 0) { 484 length = read(fd, value, sizeof(value) - 1); 485 if (length >= 0) { 486 value[length] = 0; 487 property_set(entry->d_name, value); 488 } else { 489 ERROR("Unable to read persistent property file %s errno: %d\n", path, errno); 490 } 491 close(fd); 492 } else { 493 ERROR("Unable to open persistent property file %s errno: %d\n", path, errno); 494 } 495 } 496 closedir(dir); 497 } else { 498 ERROR("Unable to open persistent property directory %s errno: %d\n", PERSISTENT_PROPERTY_DIR, errno); 499 } 500 501 persistent_properties_loaded = 1; 502 } 503 504 void property_init(void) 505 { 506 init_property_area(); 507 load_properties_from_file(PROP_PATH_RAMDISK_DEFAULT); 508 } 509 510 int properties_inited(void) 511 { 512 return property_area_inited; 513 } 514 515 void start_property_service(void) 516 { 517 int fd; 518 519 load_properties_from_file(PROP_PATH_SYSTEM_BUILD); 520 load_properties_from_file(PROP_PATH_SYSTEM_DEFAULT); 521 load_properties_from_file(PROP_PATH_LOCAL_OVERRIDE); 522 /* Read persistent properties after all default values have been loaded. */ 523 load_persistent_properties(); 524 525 fd = create_socket(PROP_SERVICE_NAME, SOCK_STREAM, 0666, 0, 0); 526 if(fd < 0) return; 527 fcntl(fd, F_SETFD, FD_CLOEXEC); 528 fcntl(fd, F_SETFL, O_NONBLOCK); 529 530 listen(fd, 8); 531 property_set_fd = fd; 532 } 533 534 int get_property_set_fd() 535 { 536 return property_set_fd; 537 } 538
