property_service.c revision cf01597121c1c08780966f22e2a62386d0e1a08f
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 50static int persistent_properties_loaded = 0; 51static int property_area_inited = 0; 52 53static int property_set_fd = -1; 54 55/* White list of permissions for setting property services. */ 56struct { 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 { "net.qmi", AID_RADIO, 0 }, 65 { "ril.", AID_RADIO, 0 }, 66 { "gsm.", AID_RADIO, 0 }, 67 { "persist.radio", AID_RADIO, 0 }, 68 { "net.dns", AID_RADIO, 0 }, 69 { "net.", AID_SYSTEM, 0 }, 70 { "dev.", AID_SYSTEM, 0 }, 71 { "runtime.", AID_SYSTEM, 0 }, 72 { "hw.", AID_SYSTEM, 0 }, 73 { "sys.", AID_SYSTEM, 0 }, 74 { "service.", AID_SYSTEM, 0 }, 75 { "wlan.", AID_SYSTEM, 0 }, 76 { "dhcp.", AID_SYSTEM, 0 }, 77 { "dhcp.", AID_DHCP, 0 }, 78 { "vpn.", AID_SYSTEM, 0 }, 79 { "vpn.", AID_VPN, 0 }, 80 { "debug.", AID_SHELL, 0 }, 81 { "log.", AID_SHELL, 0 }, 82 { "service.adb.root", AID_SHELL, 0 }, 83 { "service.adb.tcp.port", AID_SHELL, 0 }, 84 { "persist.sys.", AID_SYSTEM, 0 }, 85 { "persist.service.", AID_SYSTEM, 0 }, 86 { "persist.security.", AID_SYSTEM, 0 }, 87 { NULL, 0, 0 } 88}; 89 90/* 91 * White list of UID that are allowed to start/stop services. 92 * Currently there are no user apps that require. 93 */ 94struct { 95 const char *service; 96 unsigned int uid; 97 unsigned int gid; 98} control_perms[] = { 99 { "dumpstate",AID_SHELL, AID_LOG }, 100 { "ril-daemon",AID_RADIO, AID_RADIO }, 101 {NULL, 0, 0 } 102}; 103 104typedef struct { 105 void *data; 106 size_t size; 107 int fd; 108} workspace; 109 110static int init_workspace(workspace *w, size_t size) 111{ 112 void *data; 113 int fd; 114 115 /* dev is a tmpfs that we can use to carve a shared workspace 116 * out of, so let's do that... 117 */ 118 fd = open("/dev/__properties__", O_RDWR | O_CREAT, 0600); 119 if (fd < 0) 120 return -1; 121 122 if (ftruncate(fd, size) < 0) 123 goto out; 124 125 data = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); 126 if(data == MAP_FAILED) 127 goto out; 128 129 close(fd); 130 131 fd = open("/dev/__properties__", O_RDONLY); 132 if (fd < 0) 133 return -1; 134 135 unlink("/dev/__properties__"); 136 137 w->data = data; 138 w->size = size; 139 w->fd = fd; 140 return 0; 141 142out: 143 close(fd); 144 return -1; 145} 146 147/* (8 header words + 247 toc words) = 1020 bytes */ 148/* 1024 bytes header and toc + 247 prop_infos @ 128 bytes = 32640 bytes */ 149 150#define PA_COUNT_MAX 247 151#define PA_INFO_START 1024 152#define PA_SIZE 32768 153 154static workspace pa_workspace; 155static prop_info *pa_info_array; 156 157extern prop_area *__system_property_area__; 158 159static int init_property_area(void) 160{ 161 prop_area *pa; 162 163 if(pa_info_array) 164 return -1; 165 166 if(init_workspace(&pa_workspace, PA_SIZE)) 167 return -1; 168 169 fcntl(pa_workspace.fd, F_SETFD, FD_CLOEXEC); 170 171 pa_info_array = (void*) (((char*) pa_workspace.data) + PA_INFO_START); 172 173 pa = pa_workspace.data; 174 memset(pa, 0, PA_SIZE); 175 pa->magic = PROP_AREA_MAGIC; 176 pa->version = PROP_AREA_VERSION; 177 178 /* plug into the lib property services */ 179 __system_property_area__ = pa; 180 property_area_inited = 1; 181 return 0; 182} 183 184static void update_prop_info(prop_info *pi, const char *value, unsigned len) 185{ 186 pi->serial = pi->serial | 1; 187 memcpy(pi->value, value, len + 1); 188 pi->serial = (len << 24) | ((pi->serial + 1) & 0xffffff); 189 __futex_wake(&pi->serial, INT32_MAX); 190} 191 192static int property_write(prop_info *pi, const char *value) 193{ 194 int valuelen = strlen(value); 195 if(valuelen >= PROP_VALUE_MAX) return -1; 196 update_prop_info(pi, value, valuelen); 197 return 0; 198} 199 200 201/* 202 * Checks permissions for starting/stoping system services. 203 * AID_SYSTEM and AID_ROOT are always allowed. 204 * 205 * Returns 1 if uid allowed, 0 otherwise. 206 */ 207static int check_control_perms(const char *name, unsigned int uid, unsigned int gid) { 208 int i; 209 if (uid == AID_SYSTEM || uid == AID_ROOT) 210 return 1; 211 212 /* Search the ACL */ 213 for (i = 0; control_perms[i].service; i++) { 214 if (strcmp(control_perms[i].service, name) == 0) { 215 if ((uid && control_perms[i].uid == uid) || 216 (gid && control_perms[i].gid == gid)) { 217 return 1; 218 } 219 } 220 } 221 return 0; 222} 223 224/* 225 * Checks permissions for setting system properties. 226 * Returns 1 if uid allowed, 0 otherwise. 227 */ 228static int check_perms(const char *name, unsigned int uid, unsigned int gid) 229{ 230 int i; 231 if (uid == 0) 232 return 1; 233 234 if(!strncmp(name, "ro.", 3)) 235 name +=3; 236 237 for (i = 0; property_perms[i].prefix; i++) { 238 int tmp; 239 if (strncmp(property_perms[i].prefix, name, 240 strlen(property_perms[i].prefix)) == 0) { 241 if ((uid && property_perms[i].uid == uid) || 242 (gid && property_perms[i].gid == gid)) { 243 return 1; 244 } 245 } 246 } 247 248 return 0; 249} 250 251const char* property_get(const char *name) 252{ 253 prop_info *pi; 254 255 if(strlen(name) >= PROP_NAME_MAX) return 0; 256 257 pi = (prop_info*) __system_property_find(name); 258 259 if(pi != 0) { 260 return pi->value; 261 } else { 262 return 0; 263 } 264} 265 266static void write_persistent_property(const char *name, const char *value) 267{ 268 const char *tempPath = PERSISTENT_PROPERTY_DIR "/.temp"; 269 char path[PATH_MAX]; 270 int fd, length; 271 272 snprintf(path, sizeof(path), "%s/%s", PERSISTENT_PROPERTY_DIR, name); 273 274 fd = open(tempPath, O_WRONLY|O_CREAT|O_TRUNC, 0600); 275 if (fd < 0) { 276 ERROR("Unable to write persistent property to temp file %s errno: %d\n", tempPath, errno); 277 return; 278 } 279 write(fd, value, strlen(value)); 280 close(fd); 281 282 if (rename(tempPath, path)) { 283 unlink(tempPath); 284 ERROR("Unable to rename persistent property file %s to %s\n", tempPath, path); 285 } 286} 287 288int property_set(const char *name, const char *value) 289{ 290 prop_area *pa; 291 prop_info *pi; 292 293 int namelen = strlen(name); 294 int valuelen = strlen(value); 295 296 if(namelen >= PROP_NAME_MAX) return -1; 297 if(valuelen >= PROP_VALUE_MAX) return -1; 298 if(namelen < 1) return -1; 299 300 pi = (prop_info*) __system_property_find(name); 301 302 if(pi != 0) { 303 /* ro.* properties may NEVER be modified once set */ 304 if(!strncmp(name, "ro.", 3)) return -1; 305 306 pa = __system_property_area__; 307 update_prop_info(pi, value, valuelen); 308 pa->serial++; 309 __futex_wake(&pa->serial, INT32_MAX); 310 } else { 311 pa = __system_property_area__; 312 if(pa->count == PA_COUNT_MAX) return -1; 313 314 pi = pa_info_array + pa->count; 315 pi->serial = (valuelen << 24); 316 memcpy(pi->name, name, namelen + 1); 317 memcpy(pi->value, value, valuelen + 1); 318 319 pa->toc[pa->count] = 320 (namelen << 24) | (((unsigned) pi) - ((unsigned) pa)); 321 322 pa->count++; 323 pa->serial++; 324 __futex_wake(&pa->serial, INT32_MAX); 325 } 326 /* If name starts with "net." treat as a DNS property. */ 327 if (strncmp("net.", name, strlen("net.")) == 0) { 328 if (strcmp("net.change", name) == 0) { 329 return 0; 330 } 331 /* 332 * The 'net.change' property is a special property used track when any 333 * 'net.*' property name is updated. It is _ONLY_ updated here. Its value 334 * contains the last updated 'net.*' property. 335 */ 336 property_set("net.change", name); 337 } else if (persistent_properties_loaded && 338 strncmp("persist.", name, strlen("persist.")) == 0) { 339 /* 340 * Don't write properties to disk until after we have read all default properties 341 * to prevent them from being overwritten by default values. 342 */ 343 write_persistent_property(name, value); 344 } 345 property_changed(name, value); 346 return 0; 347} 348 349static int property_list(void (*propfn)(const char *key, const char *value, void *cookie), 350 void *cookie) 351{ 352 char name[PROP_NAME_MAX]; 353 char value[PROP_VALUE_MAX]; 354 const prop_info *pi; 355 unsigned n; 356 357 for(n = 0; (pi = __system_property_find_nth(n)); n++) { 358 __system_property_read(pi, name, value); 359 propfn(name, value, cookie); 360 } 361 return 0; 362} 363 364void handle_property_set_fd() 365{ 366 prop_msg msg; 367 int s; 368 int r; 369 int res; 370 struct ucred cr; 371 struct sockaddr_un addr; 372 socklen_t addr_size = sizeof(addr); 373 socklen_t cr_size = sizeof(cr); 374 375 if ((s = accept(property_set_fd, (struct sockaddr *) &addr, &addr_size)) < 0) { 376 return; 377 } 378 379 /* Check socket options here */ 380 if (getsockopt(s, SOL_SOCKET, SO_PEERCRED, &cr, &cr_size) < 0) { 381 close(s); 382 ERROR("Unable to recieve socket options\n"); 383 return; 384 } 385 386 r = recv(s, &msg, sizeof(msg), 0); 387 close(s); 388 if(r != sizeof(prop_msg)) { 389 ERROR("sys_prop: mis-match msg size recieved: %d expected: %d\n", 390 r, sizeof(prop_msg)); 391 return; 392 } 393 394 switch(msg.cmd) { 395 case PROP_MSG_SETPROP: 396 msg.name[PROP_NAME_MAX-1] = 0; 397 msg.value[PROP_VALUE_MAX-1] = 0; 398 399 if(memcmp(msg.name,"ctl.",4) == 0) { 400 if (check_control_perms(msg.value, cr.uid, cr.gid)) { 401 handle_control_message((char*) msg.name + 4, (char*) msg.value); 402 } else { 403 ERROR("sys_prop: Unable to %s service ctl [%s] uid:%d gid:%d pid:%d\n", 404 msg.name + 4, msg.value, cr.uid, cr.gid, cr.pid); 405 } 406 } else { 407 if (check_perms(msg.name, cr.uid, cr.gid)) { 408 property_set((char*) msg.name, (char*) msg.value); 409 } else { 410 ERROR("sys_prop: permission denied uid:%d name:%s\n", 411 cr.uid, msg.name); 412 } 413 } 414 break; 415 416 default: 417 break; 418 } 419} 420 421void get_property_workspace(int *fd, int *sz) 422{ 423 *fd = pa_workspace.fd; 424 *sz = pa_workspace.size; 425} 426 427static void load_properties(char *data) 428{ 429 char *key, *value, *eol, *sol, *tmp; 430 431 sol = data; 432 while((eol = strchr(sol, '\n'))) { 433 key = sol; 434 *eol++ = 0; 435 sol = eol; 436 437 value = strchr(key, '='); 438 if(value == 0) continue; 439 *value++ = 0; 440 441 while(isspace(*key)) key++; 442 if(*key == '#') continue; 443 tmp = value - 2; 444 while((tmp > key) && isspace(*tmp)) *tmp-- = 0; 445 446 while(isspace(*value)) value++; 447 tmp = eol - 2; 448 while((tmp > value) && isspace(*tmp)) *tmp-- = 0; 449 450 property_set(key, value); 451 } 452} 453 454static void load_properties_from_file(const char *fn) 455{ 456 char *data; 457 unsigned sz; 458 459 data = read_file(fn, &sz); 460 461 if(data != 0) { 462 load_properties(data); 463 free(data); 464 } 465} 466 467static void load_persistent_properties() 468{ 469 DIR* dir = opendir(PERSISTENT_PROPERTY_DIR); 470 struct dirent* entry; 471 char path[PATH_MAX]; 472 char value[PROP_VALUE_MAX]; 473 int fd, length; 474 475 if (dir) { 476 while ((entry = readdir(dir)) != NULL) { 477 if (strncmp("persist.", entry->d_name, strlen("persist."))) 478 continue; 479#if HAVE_DIRENT_D_TYPE 480 if (entry->d_type != DT_REG) 481 continue; 482#endif 483 /* open the file and read the property value */ 484 snprintf(path, sizeof(path), "%s/%s", PERSISTENT_PROPERTY_DIR, entry->d_name); 485 fd = open(path, O_RDONLY); 486 if (fd >= 0) { 487 length = read(fd, value, sizeof(value) - 1); 488 if (length >= 0) { 489 value[length] = 0; 490 property_set(entry->d_name, value); 491 } else { 492 ERROR("Unable to read persistent property file %s errno: %d\n", path, errno); 493 } 494 close(fd); 495 } else { 496 ERROR("Unable to open persistent property file %s errno: %d\n", path, errno); 497 } 498 } 499 closedir(dir); 500 } else { 501 ERROR("Unable to open persistent property directory %s errno: %d\n", PERSISTENT_PROPERTY_DIR, errno); 502 } 503 504 persistent_properties_loaded = 1; 505} 506 507void property_init(void) 508{ 509 init_property_area(); 510 load_properties_from_file(PROP_PATH_RAMDISK_DEFAULT); 511} 512 513int properties_inited(void) 514{ 515 return property_area_inited; 516} 517 518void start_property_service(void) 519{ 520 int fd; 521 522 load_properties_from_file(PROP_PATH_SYSTEM_BUILD); 523 load_properties_from_file(PROP_PATH_SYSTEM_DEFAULT); 524 load_properties_from_file(PROP_PATH_LOCAL_OVERRIDE); 525 /* Read persistent properties after all default values have been loaded. */ 526 load_persistent_properties(); 527 528 fd = create_socket(PROP_SERVICE_NAME, SOCK_STREAM, 0666, 0, 0); 529 if(fd < 0) return; 530 fcntl(fd, F_SETFD, FD_CLOEXEC); 531 fcntl(fd, F_SETFL, O_NONBLOCK); 532 533 listen(fd, 8); 534 property_set_fd = fd; 535} 536 537int get_property_set_fd() 538{ 539 return property_set_fd; 540} 541