devices.c revision 44b65d047cc39baf30e21bfd8dd438f6bc1f77f5
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 <errno.h> 18#include <stdio.h> 19#include <stdlib.h> 20#include <sys/stat.h> 21#include <sys/types.h> 22 23#include <fcntl.h> 24#include <dirent.h> 25#include <unistd.h> 26#include <string.h> 27 28#include <sys/socket.h> 29#include <sys/un.h> 30#include <linux/netlink.h> 31#include <private/android_filesystem_config.h> 32#include <sys/time.h> 33#include <asm/page.h> 34 35#include "devices.h" 36#include "util.h" 37#include "log.h" 38#include "list.h" 39 40#define SYSFS_PREFIX "/sys" 41#define FIRMWARE_DIR "/etc/firmware" 42 43static int device_fd = -1; 44 45struct uevent { 46 const char *action; 47 const char *path; 48 const char *subsystem; 49 const char *firmware; 50 const char *partition_name; 51 int partition_num; 52 int major; 53 int minor; 54}; 55 56static int open_uevent_socket(void) 57{ 58 struct sockaddr_nl addr; 59 int sz = 64*1024; // XXX larger? udev uses 16MB! 60 int s; 61 62 memset(&addr, 0, sizeof(addr)); 63 addr.nl_family = AF_NETLINK; 64 addr.nl_pid = getpid(); 65 addr.nl_groups = 0xffffffff; 66 67 s = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT); 68 if(s < 0) 69 return -1; 70 71 setsockopt(s, SOL_SOCKET, SO_RCVBUFFORCE, &sz, sizeof(sz)); 72 73 if(bind(s, (struct sockaddr *) &addr, sizeof(addr)) < 0) { 74 close(s); 75 return -1; 76 } 77 78 return s; 79} 80 81struct perms_ { 82 char *name; 83 mode_t perm; 84 unsigned int uid; 85 unsigned int gid; 86 unsigned short prefix; 87}; 88 89struct perm_node { 90 struct perms_ dp; 91 struct listnode plist; 92}; 93static list_declare(dev_perms); 94 95/* 96 * Permission override when in emulator mode, must be parsed before 97 * system properties is initalized. 98 */ 99int add_dev_perms(const char *name, mode_t perm, unsigned int uid, 100 unsigned int gid, unsigned short prefix) { 101 int size; 102 char *tmp = 0; 103 struct perm_node *node = malloc(sizeof (struct perm_node)); 104 if (!node) 105 return -ENOMEM; 106 107 size = strlen(name) + 1; 108 if ((node->dp.name = malloc(size)) == NULL) 109 return -ENOMEM; 110 111 memcpy(node->dp.name, name, size); 112 node->dp.perm = perm; 113 node->dp.uid = uid; 114 node->dp.gid = gid; 115 node->dp.prefix = prefix; 116 117 list_add_tail(&dev_perms, &node->plist); 118 return 0; 119} 120 121static int get_device_perm_inner(struct perms_ *perms, const char *path, 122 unsigned *uid, unsigned *gid, mode_t *perm) 123{ 124 int i; 125 for(i = 0; perms[i].name; i++) { 126 127 if(perms[i].prefix) { 128 if(strncmp(path, perms[i].name, strlen(perms[i].name))) 129 continue; 130 } else { 131 if(strcmp(path, perms[i].name)) 132 continue; 133 } 134 *uid = perms[i].uid; 135 *gid = perms[i].gid; 136 *perm = perms[i].perm; 137 return 0; 138 } 139 return -1; 140} 141 142/* First checks for emulator specific permissions specified in /proc/cmdline. */ 143static mode_t get_device_perm(const char *path, unsigned *uid, unsigned *gid) 144{ 145 mode_t perm; 146 struct listnode *node; 147 struct perm_node *perm_node; 148 struct perms_ *dp; 149 150 /* search the perms list in reverse so that ueventd.$hardware can 151 * override ueventd.rc 152 */ 153 list_for_each_reverse(node, &dev_perms) { 154 perm_node = node_to_item(node, struct perm_node, plist); 155 dp = &perm_node->dp; 156 157 if (dp->prefix) { 158 if (strncmp(path, dp->name, strlen(dp->name))) 159 continue; 160 } else { 161 if (strcmp(path, dp->name)) 162 continue; 163 } 164 *uid = dp->uid; 165 *gid = dp->gid; 166 return dp->perm; 167 } 168 /* Default if nothing found. */ 169 *uid = 0; 170 *gid = 0; 171 return 0600; 172} 173 174static void make_device(const char *path, int block, int major, int minor) 175{ 176 unsigned uid; 177 unsigned gid; 178 mode_t mode; 179 dev_t dev; 180 181 if(major > 255 || minor > 255) 182 return; 183 184 mode = get_device_perm(path, &uid, &gid) | (block ? S_IFBLK : S_IFCHR); 185 dev = (major << 8) | minor; 186 /* Temporarily change egid to avoid race condition setting the gid of the 187 * device node. Unforunately changing the euid would prevent creation of 188 * some device nodes, so the uid has to be set with chown() and is still 189 * racy. Fixing the gid race at least fixed the issue with system_server 190 * opening dynamic input devices under the AID_INPUT gid. */ 191 setegid(gid); 192 mknod(path, mode, dev); 193 chown(path, uid, -1); 194 setegid(AID_ROOT); 195} 196 197#if LOG_UEVENTS 198 199static inline suseconds_t get_usecs(void) 200{ 201 struct timeval tv; 202 gettimeofday(&tv, 0); 203 return tv.tv_sec * (suseconds_t) 1000000 + tv.tv_usec; 204} 205 206#define log_event_print(x...) INFO(x) 207 208#else 209 210#define log_event_print(fmt, args...) do { } while (0) 211#define get_usecs() 0 212 213#endif 214 215static void parse_event(const char *msg, struct uevent *uevent) 216{ 217 uevent->action = ""; 218 uevent->path = ""; 219 uevent->subsystem = ""; 220 uevent->firmware = ""; 221 uevent->major = -1; 222 uevent->minor = -1; 223 uevent->partition_name = NULL; 224 uevent->partition_num = -1; 225 226 /* currently ignoring SEQNUM */ 227 while(*msg) { 228 if(!strncmp(msg, "ACTION=", 7)) { 229 msg += 7; 230 uevent->action = msg; 231 } else if(!strncmp(msg, "DEVPATH=", 8)) { 232 msg += 8; 233 uevent->path = msg; 234 } else if(!strncmp(msg, "SUBSYSTEM=", 10)) { 235 msg += 10; 236 uevent->subsystem = msg; 237 } else if(!strncmp(msg, "FIRMWARE=", 9)) { 238 msg += 9; 239 uevent->firmware = msg; 240 } else if(!strncmp(msg, "MAJOR=", 6)) { 241 msg += 6; 242 uevent->major = atoi(msg); 243 } else if(!strncmp(msg, "MINOR=", 6)) { 244 msg += 6; 245 uevent->minor = atoi(msg); 246 } else if(!strncmp(msg, "PARTN=", 6)) { 247 msg += 6; 248 uevent->partition_num = atoi(msg); 249 } else if(!strncmp(msg, "PARTNAME=", 9)) { 250 msg += 9; 251 uevent->partition_name = msg; 252 } 253 254 /* advance to after the next \0 */ 255 while(*msg++) 256 ; 257 } 258 259 log_event_print("event { '%s', '%s', '%s', '%s', %d, %d }\n", 260 uevent->action, uevent->path, uevent->subsystem, 261 uevent->firmware, uevent->major, uevent->minor); 262} 263 264static char **parse_platform_block_device(struct uevent *uevent) 265{ 266 const char *driver; 267 const char *path; 268 char *slash; 269 int width; 270 char buf[256]; 271 char link_path[256]; 272 int fd; 273 int link_num = 0; 274 int ret; 275 char *p; 276 unsigned int size; 277 struct stat info; 278 279 char **links = malloc(sizeof(char *) * 4); 280 if (!links) 281 return NULL; 282 memset(links, 0, sizeof(char *) * 4); 283 284 /* Drop "/devices/platform/" */ 285 path = uevent->path; 286 driver = path + 18; 287 slash = strchr(driver, '/'); 288 if (!slash) 289 goto err; 290 width = slash - driver; 291 if (width <= 0) 292 goto err; 293 294 snprintf(link_path, sizeof(link_path), "/dev/block/platform/%.*s", 295 width, driver); 296 297 if (uevent->partition_name) { 298 p = strdup(uevent->partition_name); 299 sanitize(p); 300 if (asprintf(&links[link_num], "%s/by-name/%s", link_path, p) > 0) 301 link_num++; 302 else 303 links[link_num] = NULL; 304 free(p); 305 } 306 307 if (uevent->partition_num >= 0) { 308 if (asprintf(&links[link_num], "%s/by-num/p%d", link_path, uevent->partition_num) > 0) 309 link_num++; 310 else 311 links[link_num] = NULL; 312 } 313 314 slash = strrchr(path, '/'); 315 if (asprintf(&links[link_num], "%s/%s", link_path, slash + 1) > 0) 316 link_num++; 317 else 318 links[link_num] = NULL; 319 320 return links; 321 322err: 323 free(links); 324 return NULL; 325} 326 327static void handle_device_event(struct uevent *uevent) 328{ 329 char devpath[96]; 330 char *base, *name; 331 char **links = NULL; 332 int block; 333 int i; 334 335 /* if it's not a /dev device, nothing to do */ 336 if((uevent->major < 0) || (uevent->minor < 0)) 337 return; 338 339 /* do we have a name? */ 340 name = strrchr(uevent->path, '/'); 341 if(!name) 342 return; 343 name++; 344 345 /* too-long names would overrun our buffer */ 346 if(strlen(name) > 64) 347 return; 348 349 /* are we block or char? where should we live? */ 350 if(!strncmp(uevent->subsystem, "block", 5)) { 351 block = 1; 352 base = "/dev/block/"; 353 mkdir(base, 0755); 354 if (!strncmp(uevent->path, "/devices/platform/", 18)) 355 links = parse_platform_block_device(uevent); 356 } else { 357 block = 0; 358 /* this should probably be configurable somehow */ 359 if(!strncmp(uevent->subsystem, "graphics", 8)) { 360 base = "/dev/graphics/"; 361 mkdir(base, 0755); 362 } else if (!strncmp(uevent->subsystem, "oncrpc", 6)) { 363 base = "/dev/oncrpc/"; 364 mkdir(base, 0755); 365 } else if (!strncmp(uevent->subsystem, "adsp", 4)) { 366 base = "/dev/adsp/"; 367 mkdir(base, 0755); 368 } else if (!strncmp(uevent->subsystem, "msm_camera", 10)) { 369 base = "/dev/msm_camera/"; 370 mkdir(base, 0755); 371 } else if(!strncmp(uevent->subsystem, "input", 5)) { 372 base = "/dev/input/"; 373 mkdir(base, 0755); 374 } else if(!strncmp(uevent->subsystem, "mtd", 3)) { 375 base = "/dev/mtd/"; 376 mkdir(base, 0755); 377 } else if(!strncmp(uevent->subsystem, "sound", 5)) { 378 base = "/dev/snd/"; 379 mkdir(base, 0755); 380 } else if(!strncmp(uevent->subsystem, "misc", 4) && 381 !strncmp(name, "log_", 4)) { 382 base = "/dev/log/"; 383 mkdir(base, 0755); 384 name += 4; 385 } else 386 base = "/dev/"; 387 } 388 389 snprintf(devpath, sizeof(devpath), "%s%s", base, name); 390 391 if(!strcmp(uevent->action, "add")) { 392 make_device(devpath, block, uevent->major, uevent->minor); 393 if (links) { 394 for (i = 0; links[i]; i++) 395 make_link(devpath, links[i]); 396 } 397 } 398 399 if(!strcmp(uevent->action, "remove")) { 400 if (links) { 401 for (i = 0; links[i]; i++) 402 remove_link(devpath, links[i]); 403 } 404 unlink(devpath); 405 } 406 407 if (links) { 408 for (i = 0; links[i]; i++) 409 free(links[i]); 410 free(links); 411 } 412} 413 414static int load_firmware(int fw_fd, int loading_fd, int data_fd) 415{ 416 struct stat st; 417 long len_to_copy; 418 int ret = 0; 419 420 if(fstat(fw_fd, &st) < 0) 421 return -1; 422 len_to_copy = st.st_size; 423 424 write(loading_fd, "1", 1); /* start transfer */ 425 426 while (len_to_copy > 0) { 427 char buf[PAGE_SIZE]; 428 ssize_t nr; 429 430 nr = read(fw_fd, buf, sizeof(buf)); 431 if(!nr) 432 break; 433 if(nr < 0) { 434 ret = -1; 435 break; 436 } 437 438 len_to_copy -= nr; 439 while (nr > 0) { 440 ssize_t nw = 0; 441 442 nw = write(data_fd, buf + nw, nr); 443 if(nw <= 0) { 444 ret = -1; 445 goto out; 446 } 447 nr -= nw; 448 } 449 } 450 451out: 452 if(!ret) 453 write(loading_fd, "0", 1); /* successful end of transfer */ 454 else 455 write(loading_fd, "-1", 2); /* abort transfer */ 456 457 return ret; 458} 459 460static void process_firmware_event(struct uevent *uevent) 461{ 462 char *root, *loading, *data, *file; 463 int l, loading_fd, data_fd, fw_fd; 464 465 log_event_print("firmware event { '%s', '%s' }\n", 466 uevent->path, uevent->firmware); 467 468 l = asprintf(&root, SYSFS_PREFIX"%s/", uevent->path); 469 if (l == -1) 470 return; 471 472 l = asprintf(&loading, "%sloading", root); 473 if (l == -1) 474 goto root_free_out; 475 476 l = asprintf(&data, "%sdata", root); 477 if (l == -1) 478 goto loading_free_out; 479 480 l = asprintf(&file, FIRMWARE_DIR"/%s", uevent->firmware); 481 if (l == -1) 482 goto data_free_out; 483 484 loading_fd = open(loading, O_WRONLY); 485 if(loading_fd < 0) 486 goto file_free_out; 487 488 data_fd = open(data, O_WRONLY); 489 if(data_fd < 0) 490 goto loading_close_out; 491 492 fw_fd = open(file, O_RDONLY); 493 if(fw_fd < 0) 494 goto data_close_out; 495 496 if(!load_firmware(fw_fd, loading_fd, data_fd)) 497 log_event_print("firmware copy success { '%s', '%s' }\n", root, file); 498 else 499 log_event_print("firmware copy failure { '%s', '%s' }\n", root, file); 500 501 close(fw_fd); 502data_close_out: 503 close(data_fd); 504loading_close_out: 505 close(loading_fd); 506file_free_out: 507 free(file); 508data_free_out: 509 free(data); 510loading_free_out: 511 free(loading); 512root_free_out: 513 free(root); 514} 515 516static void handle_firmware_event(struct uevent *uevent) 517{ 518 pid_t pid; 519 520 if(strcmp(uevent->subsystem, "firmware")) 521 return; 522 523 if(strcmp(uevent->action, "add")) 524 return; 525 526 /* we fork, to avoid making large memory allocations in init proper */ 527 pid = fork(); 528 if (!pid) { 529 process_firmware_event(uevent); 530 exit(EXIT_SUCCESS); 531 } 532} 533 534#define UEVENT_MSG_LEN 1024 535void handle_device_fd() 536{ 537 char msg[UEVENT_MSG_LEN+2]; 538 int n; 539 540 while((n = recv(device_fd, msg, UEVENT_MSG_LEN, 0)) > 0) { 541 struct uevent uevent; 542 543 if(n == UEVENT_MSG_LEN) /* overflow -- discard */ 544 continue; 545 546 msg[n] = '\0'; 547 msg[n+1] = '\0'; 548 549 parse_event(msg, &uevent); 550 551 handle_device_event(&uevent); 552 handle_firmware_event(&uevent); 553 } 554} 555 556/* Coldboot walks parts of the /sys tree and pokes the uevent files 557** to cause the kernel to regenerate device add events that happened 558** before init's device manager was started 559** 560** We drain any pending events from the netlink socket every time 561** we poke another uevent file to make sure we don't overrun the 562** socket's buffer. 563*/ 564 565static void do_coldboot(DIR *d) 566{ 567 struct dirent *de; 568 int dfd, fd; 569 570 dfd = dirfd(d); 571 572 fd = openat(dfd, "uevent", O_WRONLY); 573 if(fd >= 0) { 574 write(fd, "add\n", 4); 575 close(fd); 576 handle_device_fd(); 577 } 578 579 while((de = readdir(d))) { 580 DIR *d2; 581 582 if(de->d_type != DT_DIR || de->d_name[0] == '.') 583 continue; 584 585 fd = openat(dfd, de->d_name, O_RDONLY | O_DIRECTORY); 586 if(fd < 0) 587 continue; 588 589 d2 = fdopendir(fd); 590 if(d2 == 0) 591 close(fd); 592 else { 593 do_coldboot(d2); 594 closedir(d2); 595 } 596 } 597} 598 599static void coldboot(const char *path) 600{ 601 DIR *d = opendir(path); 602 if(d) { 603 do_coldboot(d); 604 closedir(d); 605 } 606} 607 608void device_init(void) 609{ 610 suseconds_t t0, t1; 611 struct stat info; 612 int fd; 613 614 device_fd = open_uevent_socket(); 615 if(device_fd < 0) 616 return; 617 618 fcntl(device_fd, F_SETFD, FD_CLOEXEC); 619 fcntl(device_fd, F_SETFL, O_NONBLOCK); 620 621 if (stat(coldboot_done, &info) < 0) { 622 t0 = get_usecs(); 623 coldboot("/sys/class"); 624 coldboot("/sys/block"); 625 coldboot("/sys/devices"); 626 t1 = get_usecs(); 627 fd = open(coldboot_done, O_WRONLY|O_CREAT, 0000); 628 close(fd); 629 log_event_print("coldboot %ld uS\n", ((long) (t1 - t0))); 630 } else { 631 log_event_print("skipping coldboot, already done\n"); 632 } 633} 634 635int get_device_fd() 636{ 637 return device_fd; 638} 639