devices.cpp revision 482f36cf74c0461bbad4a33df27d1b8e72ccc2d2
1/* 2 * Copyright (C) 2007-2014 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 "devices.h" 18 19#include <dirent.h> 20#include <errno.h> 21#include <fcntl.h> 22#include <fnmatch.h> 23#include <grp.h> 24#include <libgen.h> 25#include <linux/netlink.h> 26#include <pwd.h> 27#include <stddef.h> 28#include <stdio.h> 29#include <stdlib.h> 30#include <string.h> 31#include <sys/sendfile.h> 32#include <sys/socket.h> 33#include <sys/time.h> 34#include <sys/un.h> 35#include <sys/wait.h> 36#include <unistd.h> 37 38#include <algorithm> 39#include <memory> 40#include <thread> 41 42#include <android-base/file.h> 43#include <android-base/logging.h> 44#include <android-base/stringprintf.h> 45#include <android-base/strings.h> 46#include <android-base/unique_fd.h> 47#include <cutils/uevent.h> 48#include <private/android_filesystem_config.h> 49#include <selinux/android.h> 50#include <selinux/label.h> 51#include <selinux/selinux.h> 52 53#include "keyword_map.h" 54#include "ueventd.h" 55#include "util.h" 56 57#ifdef _INIT_INIT_H 58#error "Do not include init.h in files used by ueventd or watchdogd; it will expose init's globals" 59#endif 60 61static selabel_handle* sehandle; 62 63static android::base::unique_fd device_fd; 64 65Permissions::Permissions(const std::string& name, mode_t perm, uid_t uid, gid_t gid) 66 : name_(name), perm_(perm), uid_(uid), gid_(gid), prefix_(false), wildcard_(false) { 67 // If the first * is the last character, then we'll treat name_ as a prefix 68 // Otherwise, if a * is present, then we do a full fnmatch(). 69 auto wildcard_position = name_.find('*'); 70 if (wildcard_position == name_.length() - 1) { 71 prefix_ = true; 72 name_.pop_back(); 73 } else if (wildcard_position != std::string::npos) { 74 wildcard_ = true; 75 } 76} 77 78bool Permissions::Match(const std::string& path) const { 79 if (prefix_) { 80 return android::base::StartsWith(path, name_.c_str()); 81 } else if (wildcard_) { 82 return fnmatch(name_.c_str(), path.c_str(), FNM_PATHNAME) == 0; 83 } else { 84 return path == name_; 85 } 86 87 return false; 88} 89 90bool SysfsPermissions::MatchWithSubsystem(const std::string& path, 91 const std::string& subsystem) const { 92 std::string path_basename = android::base::Basename(path); 93 if (name().find(subsystem) != std::string::npos) { 94 if (Match("/sys/class/" + subsystem + "/" + path_basename)) return true; 95 if (Match("/sys/bus/" + subsystem + "/devices/" + path_basename)) return true; 96 } 97 return Match(path); 98} 99 100void SysfsPermissions::SetPermissions(const std::string& path) const { 101 std::string attribute_file = path + "/" + attribute_; 102 LOG(INFO) << "fixup " << attribute_file << " " << uid() << " " << gid() << " " << std::oct 103 << perm(); 104 chown(attribute_file.c_str(), uid(), gid()); 105 chmod(attribute_file.c_str(), perm()); 106} 107 108// TODO: Move these to be member variables of a future devices class. 109std::vector<Permissions> dev_permissions; 110std::vector<SysfsPermissions> sysfs_permissions; 111 112bool ParsePermissionsLine(std::vector<std::string>&& args, std::string* err, bool is_sysfs) { 113 if (is_sysfs && args.size() != 5) { 114 *err = "/sys/ lines must have 5 entries"; 115 return false; 116 } 117 118 if (!is_sysfs && args.size() != 4) { 119 *err = "/dev/ lines must have 4 entries"; 120 return false; 121 } 122 123 auto it = args.begin(); 124 const std::string& name = *it++; 125 126 std::string sysfs_attribute; 127 if (is_sysfs) sysfs_attribute = *it++; 128 129 // args is now common to both sys and dev entries and contains: <perm> <uid> <gid> 130 std::string& perm_string = *it++; 131 char* end_pointer = 0; 132 mode_t perm = strtol(perm_string.c_str(), &end_pointer, 8); 133 if (end_pointer == nullptr || *end_pointer != '\0') { 134 *err = "invalid mode '" + perm_string + "'"; 135 return false; 136 } 137 138 std::string& uid_string = *it++; 139 passwd* pwd = getpwnam(uid_string.c_str()); 140 if (!pwd) { 141 *err = "invalid uid '" + uid_string + "'"; 142 return false; 143 } 144 uid_t uid = pwd->pw_uid; 145 146 std::string& gid_string = *it++; 147 struct group* grp = getgrnam(gid_string.c_str()); 148 if (!grp) { 149 *err = "invalid gid '" + gid_string + "'"; 150 return false; 151 } 152 gid_t gid = grp->gr_gid; 153 154 if (is_sysfs) { 155 sysfs_permissions.emplace_back(name, sysfs_attribute, perm, uid, gid); 156 } else { 157 dev_permissions.emplace_back(name, perm, uid, gid); 158 } 159 return true; 160} 161 162// TODO: Move this to be a member variable of a future devices class. 163static std::vector<Subsystem> subsystems; 164 165std::string Subsystem::ParseDevPath(uevent* uevent) const { 166 std::string devname = devname_source_ == DevnameSource::DEVNAME_UEVENT_DEVNAME 167 ? uevent->device_name 168 : android::base::Basename(uevent->path); 169 170 return dir_name_ + "/" + devname; 171} 172 173bool SubsystemParser::ParseSection(std::vector<std::string>&& args, const std::string& filename, 174 int line, std::string* err) { 175 if (args.size() != 2) { 176 *err = "subsystems must have exactly one name"; 177 return false; 178 } 179 180 if (std::find(subsystems.begin(), subsystems.end(), args[1]) != subsystems.end()) { 181 *err = "ignoring duplicate subsystem entry"; 182 return false; 183 } 184 185 subsystem_.name_ = args[1]; 186 187 return true; 188} 189 190bool SubsystemParser::ParseDevName(std::vector<std::string>&& args, std::string* err) { 191 if (args[1] == "uevent_devname") { 192 subsystem_.devname_source_ = Subsystem::DevnameSource::DEVNAME_UEVENT_DEVNAME; 193 return true; 194 } 195 if (args[1] == "uevent_devpath") { 196 subsystem_.devname_source_ = Subsystem::DevnameSource::DEVNAME_UEVENT_DEVPATH; 197 return true; 198 } 199 200 *err = "invalid devname '" + args[1] + "'"; 201 return false; 202} 203 204bool SubsystemParser::ParseDirName(std::vector<std::string>&& args, std::string* err) { 205 if (args[1].front() != '/') { 206 *err = "dirname '" + args[1] + " ' does not start with '/'"; 207 return false; 208 } 209 210 subsystem_.dir_name_ = args[1]; 211 return true; 212} 213 214bool SubsystemParser::ParseLineSection(std::vector<std::string>&& args, int line, std::string* err) { 215 using OptionParser = 216 bool (SubsystemParser::*)(std::vector<std::string> && args, std::string * err); 217 static class OptionParserMap : public KeywordMap<OptionParser> { 218 private: 219 const Map& map() const override { 220 // clang-format off 221 static const Map option_parsers = { 222 {"devname", {1, 1, &SubsystemParser::ParseDevName}}, 223 {"dirname", {1, 1, &SubsystemParser::ParseDirName}}, 224 }; 225 // clang-format on 226 return option_parsers; 227 } 228 } parser_map; 229 230 auto parser = parser_map.FindFunction(args, err); 231 232 if (!parser) { 233 return false; 234 } 235 236 return (this->*parser)(std::move(args), err); 237} 238 239void SubsystemParser::EndSection() { 240 subsystems.emplace_back(std::move(subsystem_)); 241} 242 243static void fixup_sys_permissions(const std::string& upath, const std::string& subsystem) { 244 // upaths omit the "/sys" that paths in this list 245 // contain, so we prepend it... 246 std::string path = "/sys" + upath; 247 248 for (const auto& s : sysfs_permissions) { 249 if (s.MatchWithSubsystem(path, subsystem)) s.SetPermissions(path); 250 } 251 252 if (access(path.c_str(), F_OK) == 0) { 253 LOG(VERBOSE) << "restorecon_recursive: " << path; 254 selinux_android_restorecon(path.c_str(), SELINUX_ANDROID_RESTORECON_RECURSE); 255 } 256} 257 258static std::tuple<mode_t, uid_t, gid_t> get_device_permissions( 259 const std::string& path, const std::vector<std::string>& links) { 260 // Search the perms list in reverse so that ueventd.$hardware can override ueventd.rc. 261 for (auto it = dev_permissions.rbegin(); it != dev_permissions.rend(); ++it) { 262 if (it->Match(path) || std::any_of(links.begin(), links.end(), 263 [it](const auto& link) { return it->Match(link); })) { 264 return {it->perm(), it->uid(), it->gid()}; 265 } 266 } 267 /* Default if nothing found. */ 268 return {0600, 0, 0}; 269} 270 271static void make_device(const std::string& path, int block, int major, int minor, 272 const std::vector<std::string>& links) { 273 dev_t dev; 274 char *secontext = NULL; 275 276 auto [mode, uid, gid] = get_device_permissions(path, links); 277 mode |= (block ? S_IFBLK : S_IFCHR); 278 279 if (sehandle) { 280 std::vector<const char*> c_links; 281 for (const auto& link : links) { 282 c_links.emplace_back(link.c_str()); 283 } 284 c_links.emplace_back(nullptr); 285 if (selabel_lookup_best_match(sehandle, &secontext, path.c_str(), &c_links[0], mode)) { 286 PLOG(ERROR) << "Device '" << path << "' not created; cannot find SELinux label"; 287 return; 288 } 289 setfscreatecon(secontext); 290 } 291 292 dev = makedev(major, minor); 293 /* Temporarily change egid to avoid race condition setting the gid of the 294 * device node. Unforunately changing the euid would prevent creation of 295 * some device nodes, so the uid has to be set with chown() and is still 296 * racy. Fixing the gid race at least fixed the issue with system_server 297 * opening dynamic input devices under the AID_INPUT gid. */ 298 if (setegid(gid)) { 299 PLOG(ERROR) << "setegid(" << gid << ") for " << path << " device failed"; 300 goto out; 301 } 302 /* If the node already exists update its SELinux label to handle cases when 303 * it was created with the wrong context during coldboot procedure. */ 304 if (mknod(path.c_str(), mode, dev) && (errno == EEXIST) && secontext) { 305 char* fcon = nullptr; 306 int rc = lgetfilecon(path.c_str(), &fcon); 307 if (rc < 0) { 308 PLOG(ERROR) << "Cannot get SELinux label on '" << path << "' device"; 309 goto out; 310 } 311 312 bool different = strcmp(fcon, secontext) != 0; 313 freecon(fcon); 314 315 if (different && lsetfilecon(path.c_str(), secontext)) { 316 PLOG(ERROR) << "Cannot set '" << secontext << "' SELinux label on '" << path << "' device"; 317 } 318 } 319 320out: 321 chown(path.c_str(), uid, -1); 322 if (setegid(AID_ROOT)) { 323 PLOG(FATAL) << "setegid(AID_ROOT) failed"; 324 } 325 326 if (secontext) { 327 freecon(secontext); 328 setfscreatecon(NULL); 329 } 330} 331 332// TODO: Move this to be a member variable of a future devices class. 333std::vector<std::string> platform_devices; 334 335// Given a path that may start with a platform device, find the length of the 336// platform device prefix. If it doesn't start with a platform device, return false 337bool find_platform_device(const std::string& path, std::string* out_path) { 338 out_path->clear(); 339 // platform_devices is searched backwards, since parents are added before their children, 340 // and we want to match as deep of a child as we can. 341 for (auto it = platform_devices.rbegin(); it != platform_devices.rend(); ++it) { 342 auto platform_device_path_length = it->length(); 343 if (platform_device_path_length < path.length() && 344 path[platform_device_path_length] == '/' && 345 android::base::StartsWith(path, it->c_str())) { 346 *out_path = *it; 347 return true; 348 } 349 } 350 return false; 351} 352 353/* Given a path that may start with a PCI device, populate the supplied buffer 354 * with the PCI domain/bus number and the peripheral ID and return 0. 355 * If it doesn't start with a PCI device, or there is some error, return -1 */ 356static bool find_pci_device_prefix(const std::string& path, std::string* result) { 357 result->clear(); 358 359 if (!android::base::StartsWith(path, "/devices/pci")) return false; 360 361 /* Beginning of the prefix is the initial "pci" after "/devices/" */ 362 std::string::size_type start = 9; 363 364 /* End of the prefix is two path '/' later, capturing the domain/bus number 365 * and the peripheral ID. Example: pci0000:00/0000:00:1f.2 */ 366 auto end = path.find('/', start); 367 if (end == std::string::npos) return false; 368 369 end = path.find('/', end + 1); 370 if (end == std::string::npos) return false; 371 372 auto length = end - start; 373 if (length <= 4) { 374 // The minimum string that will get to this check is 'pci/', which is malformed, 375 // so return false 376 return false; 377 } 378 379 *result = path.substr(start, length); 380 return true; 381} 382 383/* Given a path that may start with a virtual block device, populate 384 * the supplied buffer with the virtual block device ID and return 0. 385 * If it doesn't start with a virtual block device, or there is some 386 * error, return -1 */ 387static bool find_vbd_device_prefix(const std::string& path, std::string* result) { 388 result->clear(); 389 390 if (!android::base::StartsWith(path, "/devices/vbd-")) return false; 391 392 /* Beginning of the prefix is the initial "vbd-" after "/devices/" */ 393 std::string::size_type start = 13; 394 395 /* End of the prefix is one path '/' later, capturing the 396 virtual block device ID. Example: 768 */ 397 auto end = path.find('/', start); 398 if (end == std::string::npos) return false; 399 400 auto length = end - start; 401 if (length == 0) return false; 402 403 *result = path.substr(start, length); 404 return true; 405} 406 407void parse_event(const char* msg, uevent* uevent) { 408 uevent->partition_num = -1; 409 uevent->major = -1; 410 uevent->minor = -1; 411 // currently ignoring SEQNUM 412 while(*msg) { 413 if(!strncmp(msg, "ACTION=", 7)) { 414 msg += 7; 415 uevent->action = msg; 416 } else if(!strncmp(msg, "DEVPATH=", 8)) { 417 msg += 8; 418 uevent->path = msg; 419 } else if(!strncmp(msg, "SUBSYSTEM=", 10)) { 420 msg += 10; 421 uevent->subsystem = msg; 422 } else if(!strncmp(msg, "FIRMWARE=", 9)) { 423 msg += 9; 424 uevent->firmware = msg; 425 } else if(!strncmp(msg, "MAJOR=", 6)) { 426 msg += 6; 427 uevent->major = atoi(msg); 428 } else if(!strncmp(msg, "MINOR=", 6)) { 429 msg += 6; 430 uevent->minor = atoi(msg); 431 } else if(!strncmp(msg, "PARTN=", 6)) { 432 msg += 6; 433 uevent->partition_num = atoi(msg); 434 } else if(!strncmp(msg, "PARTNAME=", 9)) { 435 msg += 9; 436 uevent->partition_name = msg; 437 } else if(!strncmp(msg, "DEVNAME=", 8)) { 438 msg += 8; 439 uevent->device_name = msg; 440 } 441 442 // advance to after the next \0 443 while(*msg++) 444 ; 445 } 446 447 if (LOG_UEVENTS) { 448 LOG(INFO) << "event { '" << uevent->action << "', '" << uevent->path << "', '" 449 << uevent->subsystem << "', '" << uevent->firmware << "', " << uevent->major 450 << ", " << uevent->minor << " }"; 451 } 452} 453 454std::vector<std::string> get_character_device_symlinks(uevent* uevent) { 455 std::string parent_device; 456 if (!find_platform_device(uevent->path, &parent_device)) return {}; 457 458 // skip path to the parent driver 459 std::string path = uevent->path.substr(parent_device.length()); 460 461 if (!android::base::StartsWith(path, "/usb")) return {}; 462 463 // skip root hub name and device. use device interface 464 // skip 3 slashes, including the first / by starting the search at the 1st character, not 0th. 465 // then extract what comes between the 3rd and 4th slash 466 // e.g. "/usb/usb_device/name/tty2-1:1.0" -> "name" 467 468 std::string::size_type start = 0; 469 start = path.find('/', start + 1); 470 if (start == std::string::npos) return {}; 471 472 start = path.find('/', start + 1); 473 if (start == std::string::npos) return {}; 474 475 auto end = path.find('/', start + 1); 476 if (end == std::string::npos) return {}; 477 478 start++; // Skip the first '/' 479 480 auto length = end - start; 481 if (length == 0) return {}; 482 483 auto name_string = path.substr(start, length); 484 485 std::vector<std::string> links; 486 links.emplace_back("/dev/usb/" + uevent->subsystem + name_string); 487 488 mkdir("/dev/usb", 0755); 489 490 return links; 491} 492 493// replaces any unacceptable characters with '_', the 494// length of the resulting string is equal to the input string 495void sanitize_partition_name(std::string* string) { 496 const char* accept = 497 "abcdefghijklmnopqrstuvwxyz" 498 "ABCDEFGHIJKLMNOPQRSTUVWXYZ" 499 "0123456789" 500 "_-."; 501 502 if (!string) return; 503 504 std::string::size_type pos = 0; 505 while ((pos = string->find_first_not_of(accept, pos)) != std::string::npos) { 506 (*string)[pos] = '_'; 507 } 508} 509 510std::vector<std::string> get_block_device_symlinks(uevent* uevent) { 511 std::string device; 512 std::string type; 513 514 if (find_platform_device(uevent->path, &device)) { 515 // Skip /devices/platform or /devices/ if present 516 static const std::string devices_platform_prefix = "/devices/platform/"; 517 static const std::string devices_prefix = "/devices/"; 518 519 if (android::base::StartsWith(device, devices_platform_prefix.c_str())) { 520 device = device.substr(devices_platform_prefix.length()); 521 } else if (android::base::StartsWith(device, devices_prefix.c_str())) { 522 device = device.substr(devices_prefix.length()); 523 } 524 525 type = "platform"; 526 } else if (find_pci_device_prefix(uevent->path, &device)) { 527 type = "pci"; 528 } else if (find_vbd_device_prefix(uevent->path, &device)) { 529 type = "vbd"; 530 } else { 531 return {}; 532 } 533 534 std::vector<std::string> links; 535 536 LOG(VERBOSE) << "found " << type << " device " << device; 537 538 auto link_path = "/dev/block/" + type + "/" + device; 539 540 if (!uevent->partition_name.empty()) { 541 std::string partition_name_sanitized(uevent->partition_name); 542 sanitize_partition_name(&partition_name_sanitized); 543 if (partition_name_sanitized != uevent->partition_name) { 544 LOG(VERBOSE) << "Linking partition '" << uevent->partition_name << "' as '" 545 << partition_name_sanitized << "'"; 546 } 547 links.emplace_back(link_path + "/by-name/" + partition_name_sanitized); 548 } 549 550 if (uevent->partition_num >= 0) { 551 links.emplace_back(link_path + "/by-num/p" + std::to_string(uevent->partition_num)); 552 } 553 554 auto last_slash = uevent->path.rfind('/'); 555 links.emplace_back(link_path + "/" + uevent->path.substr(last_slash + 1)); 556 557 return links; 558} 559 560static void make_link_init(const std::string& oldpath, const std::string& newpath) { 561 if (mkdir_recursive(dirname(newpath.c_str()), 0755, sehandle)) { 562 PLOG(ERROR) << "Failed to create directory " << dirname(newpath.c_str()); 563 } 564 565 if (symlink(oldpath.c_str(), newpath.c_str()) && errno != EEXIST) { 566 PLOG(ERROR) << "Failed to symlink " << oldpath << " to " << newpath; 567 } 568} 569 570static void remove_link(const std::string& oldpath, const std::string& newpath) { 571 std::string path; 572 if (android::base::Readlink(newpath, &path) && path == oldpath) unlink(newpath.c_str()); 573} 574 575static void handle_device(const std::string& action, const std::string& devpath, int block, 576 int major, int minor, const std::vector<std::string>& links) { 577 if (action == "add") { 578 make_device(devpath, block, major, minor, links); 579 for (const auto& link : links) { 580 make_link_init(devpath, link); 581 } 582 } 583 584 if (action == "remove") { 585 for (const auto& link : links) { 586 remove_link(devpath, link); 587 } 588 unlink(devpath.c_str()); 589 } 590} 591 592void handle_platform_device_event(uevent* uevent) { 593 if (uevent->action == "add") { 594 platform_devices.emplace_back(uevent->path); 595 } else if (uevent->action == "remove") { 596 auto it = std::find(platform_devices.begin(), platform_devices.end(), uevent->path); 597 if (it != platform_devices.end()) platform_devices.erase(it); 598 } 599} 600 601static void handle_block_device_event(uevent* uevent) { 602 // if it's not a /dev device, nothing to do 603 if (uevent->major < 0 || uevent->minor < 0) return; 604 605 const char* base = "/dev/block/"; 606 make_dir(base, 0755, sehandle); 607 608 std::string name = android::base::Basename(uevent->path); 609 std::string devpath = base + name; 610 611 std::vector<std::string> links; 612 if (android::base::StartsWith(uevent->path, "/devices")) { 613 links = get_block_device_symlinks(uevent); 614 } 615 616 handle_device(uevent->action, devpath, 1, uevent->major, uevent->minor, links); 617} 618 619static void handle_generic_device_event(uevent* uevent) { 620 // if it's not a /dev device, nothing to do 621 if (uevent->major < 0 || uevent->minor < 0) return; 622 623 std::string devpath; 624 625 if (android::base::StartsWith(uevent->subsystem, "usb")) { 626 if (uevent->subsystem == "usb") { 627 if (!uevent->device_name.empty()) { 628 devpath = "/dev/" + uevent->device_name; 629 } else { 630 // This imitates the file system that would be created 631 // if we were using devfs instead. 632 // Minors are broken up into groups of 128, starting at "001" 633 int bus_id = uevent->minor / 128 + 1; 634 int device_id = uevent->minor % 128 + 1; 635 devpath = android::base::StringPrintf("/dev/bus/usb/%03d/%03d", bus_id, device_id); 636 } 637 } else { 638 // ignore other USB events 639 return; 640 } 641 } else if (auto subsystem = std::find(subsystems.begin(), subsystems.end(), uevent->subsystem); 642 subsystem != subsystems.end()) { 643 devpath = subsystem->ParseDevPath(uevent); 644 } else { 645 devpath = "/dev/" + android::base::Basename(uevent->path); 646 } 647 648 mkdir_recursive(android::base::Dirname(devpath), 0755, sehandle); 649 650 auto links = get_character_device_symlinks(uevent); 651 652 handle_device(uevent->action, devpath, 0, uevent->major, uevent->minor, links); 653} 654 655static void handle_device_event(struct uevent *uevent) 656{ 657 if (uevent->action == "add" || uevent->action == "change" || uevent->action == "online") { 658 fixup_sys_permissions(uevent->path, uevent->subsystem); 659 } 660 661 if (uevent->subsystem == "block") { 662 handle_block_device_event(uevent); 663 } else if (uevent->subsystem == "platform") { 664 handle_platform_device_event(uevent); 665 } else { 666 handle_generic_device_event(uevent); 667 } 668} 669 670static void load_firmware(uevent* uevent, const std::string& root, 671 int fw_fd, size_t fw_size, 672 int loading_fd, int data_fd) { 673 // Start transfer. 674 android::base::WriteFully(loading_fd, "1", 1); 675 676 // Copy the firmware. 677 int rc = sendfile(data_fd, fw_fd, nullptr, fw_size); 678 if (rc == -1) { 679 PLOG(ERROR) << "firmware: sendfile failed { '" << root << "', '" << uevent->firmware << "' }"; 680 } 681 682 // Tell the firmware whether to abort or commit. 683 const char* response = (rc != -1) ? "0" : "-1"; 684 android::base::WriteFully(loading_fd, response, strlen(response)); 685} 686 687static int is_booting() { 688 return access("/dev/.booting", F_OK) == 0; 689} 690 691static void process_firmware_event(uevent* uevent) { 692 int booting = is_booting(); 693 694 LOG(INFO) << "firmware: loading '" << uevent->firmware << "' for '" << uevent->path << "'"; 695 696 std::string root = "/sys" + uevent->path; 697 std::string loading = root + "/loading"; 698 std::string data = root + "/data"; 699 700 android::base::unique_fd loading_fd(open(loading.c_str(), O_WRONLY|O_CLOEXEC)); 701 if (loading_fd == -1) { 702 PLOG(ERROR) << "couldn't open firmware loading fd for " << uevent->firmware; 703 return; 704 } 705 706 android::base::unique_fd data_fd(open(data.c_str(), O_WRONLY|O_CLOEXEC)); 707 if (data_fd == -1) { 708 PLOG(ERROR) << "couldn't open firmware data fd for " << uevent->firmware; 709 return; 710 } 711 712 static const char* firmware_dirs[] = {"/etc/firmware/", "/vendor/firmware/", 713 "/firmware/image/"}; 714 715try_loading_again: 716 for (size_t i = 0; i < arraysize(firmware_dirs); i++) { 717 std::string file = firmware_dirs[i] + uevent->firmware; 718 android::base::unique_fd fw_fd(open(file.c_str(), O_RDONLY|O_CLOEXEC)); 719 struct stat sb; 720 if (fw_fd != -1 && fstat(fw_fd, &sb) != -1) { 721 load_firmware(uevent, root, fw_fd, sb.st_size, loading_fd, data_fd); 722 return; 723 } 724 } 725 726 if (booting) { 727 // If we're not fully booted, we may be missing 728 // filesystems needed for firmware, wait and retry. 729 std::this_thread::sleep_for(100ms); 730 booting = is_booting(); 731 goto try_loading_again; 732 } 733 734 LOG(ERROR) << "firmware: could not find firmware for " << uevent->firmware; 735 736 // Write "-1" as our response to the kernel's firmware request, since we have nothing for it. 737 write(loading_fd, "-1", 2); 738} 739 740static void handle_firmware_event(uevent* uevent) { 741 if (uevent->subsystem != "firmware" || uevent->action != "add") return; 742 743 // Loading the firmware in a child means we can do that in parallel... 744 // (We ignore SIGCHLD rather than wait for our children.) 745 pid_t pid = fork(); 746 if (pid == 0) { 747 Timer t; 748 process_firmware_event(uevent); 749 LOG(INFO) << "loading " << uevent->path << " took " << t; 750 _exit(EXIT_SUCCESS); 751 } else if (pid == -1) { 752 PLOG(ERROR) << "could not fork to process firmware event for " << uevent->firmware; 753 } 754} 755 756static bool inline should_stop_coldboot(coldboot_action_t act) 757{ 758 return (act == COLDBOOT_STOP || act == COLDBOOT_FINISH); 759} 760 761#define UEVENT_MSG_LEN 2048 762 763static inline coldboot_action_t handle_device_fd_with( 764 std::function<coldboot_action_t(uevent* uevent)> handle_uevent) 765{ 766 char msg[UEVENT_MSG_LEN+2]; 767 int n; 768 while ((n = uevent_kernel_multicast_recv(device_fd, msg, UEVENT_MSG_LEN)) > 0) { 769 if(n >= UEVENT_MSG_LEN) /* overflow -- discard */ 770 continue; 771 772 msg[n] = '\0'; 773 msg[n+1] = '\0'; 774 775 uevent uevent; 776 parse_event(msg, &uevent); 777 coldboot_action_t act = handle_uevent(&uevent); 778 if (should_stop_coldboot(act)) 779 return act; 780 } 781 782 return COLDBOOT_CONTINUE; 783} 784 785coldboot_action_t handle_device_fd(coldboot_callback fn) 786{ 787 coldboot_action_t ret = handle_device_fd_with( 788 [&](uevent* uevent) -> coldboot_action_t { 789 // default is to always create the devices 790 coldboot_action_t act = COLDBOOT_CREATE; 791 if (fn) { 792 act = fn(uevent); 793 } 794 795 if (act == COLDBOOT_CREATE || act == COLDBOOT_STOP) { 796 handle_device_event(uevent); 797 handle_firmware_event(uevent); 798 } 799 800 return act; 801 }); 802 803 return ret; 804} 805 806/* Coldboot walks parts of the /sys tree and pokes the uevent files 807** to cause the kernel to regenerate device add events that happened 808** before init's device manager was started 809** 810** We drain any pending events from the netlink socket every time 811** we poke another uevent file to make sure we don't overrun the 812** socket's buffer. 813*/ 814 815static coldboot_action_t do_coldboot(DIR *d, coldboot_callback fn) 816{ 817 struct dirent *de; 818 int dfd, fd; 819 coldboot_action_t act = COLDBOOT_CONTINUE; 820 821 dfd = dirfd(d); 822 823 fd = openat(dfd, "uevent", O_WRONLY); 824 if (fd >= 0) { 825 write(fd, "add\n", 4); 826 close(fd); 827 act = handle_device_fd(fn); 828 if (should_stop_coldboot(act)) 829 return act; 830 } 831 832 while (!should_stop_coldboot(act) && (de = readdir(d))) { 833 DIR *d2; 834 835 if(de->d_type != DT_DIR || de->d_name[0] == '.') 836 continue; 837 838 fd = openat(dfd, de->d_name, O_RDONLY | O_DIRECTORY); 839 if(fd < 0) 840 continue; 841 842 d2 = fdopendir(fd); 843 if(d2 == 0) 844 close(fd); 845 else { 846 act = do_coldboot(d2, fn); 847 closedir(d2); 848 } 849 } 850 851 // default is always to continue looking for uevents 852 return act; 853} 854 855static coldboot_action_t coldboot(const char *path, coldboot_callback fn) 856{ 857 std::unique_ptr<DIR, decltype(&closedir)> d(opendir(path), closedir); 858 if (d) { 859 return do_coldboot(d.get(), fn); 860 } 861 862 return COLDBOOT_CONTINUE; 863} 864 865void device_init(const char* path, coldboot_callback fn) { 866 if (!sehandle) { 867 sehandle = selinux_android_file_context_handle(); 868 } 869 // open uevent socket and selinux status only if it hasn't been 870 // done before 871 if (device_fd == -1) { 872 /* is 256K enough? udev uses 16MB! */ 873 device_fd.reset(uevent_open_socket(256 * 1024, true)); 874 if (device_fd == -1) { 875 return; 876 } 877 fcntl(device_fd, F_SETFL, O_NONBLOCK); 878 } 879 880 if (access(COLDBOOT_DONE, F_OK) == 0) { 881 LOG(VERBOSE) << "Skipping coldboot, already done!"; 882 return; 883 } 884 885 Timer t; 886 coldboot_action_t act; 887 if (!path) { 888 act = coldboot("/sys/class", fn); 889 if (!should_stop_coldboot(act)) { 890 act = coldboot("/sys/block", fn); 891 if (!should_stop_coldboot(act)) { 892 act = coldboot("/sys/devices", fn); 893 } 894 } 895 } else { 896 act = coldboot(path, fn); 897 } 898 899 // If we have a callback, then do as it says. If no, then the default is 900 // to always create COLDBOOT_DONE file. 901 if (!fn || (act == COLDBOOT_FINISH)) { 902 close(open(COLDBOOT_DONE, O_WRONLY|O_CREAT|O_CLOEXEC, 0000)); 903 } 904 905 LOG(INFO) << "Coldboot took " << t; 906} 907 908void device_close() { 909 platform_devices.clear(); 910 device_fd.reset(); 911} 912 913int get_device_fd() { 914 return device_fd; 915} 916