1 /*
2 * Copyright (C) 2008 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 "util.h"
18
19 #include <ctype.h>
20 #include <errno.h>
21 #include <fcntl.h>
22 #include <pwd.h>
23 #include <signal.h>
24 #include <stdarg.h>
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <string.h>
28 #include <sys/socket.h>
29 #include <sys/un.h>
30 #include <time.h>
31 #include <unistd.h>
32
33 #include <mutex>
34 #include <thread>
35 #include <vector>
36
37 #include <android-base/file.h>
38 #include <android-base/logging.h>
39 #include <android-base/properties.h>
40 #include <android-base/scopeguard.h>
41 #include <android-base/strings.h>
42 #include <android-base/unique_fd.h>
43 #include <cutils/sockets.h>
44 #include <selinux/android.h>
45
46 #ifdef INIT_FULL_SOURCES
47 #include <android/api-level.h>
48 #include <sys/system_properties.h>
49
50 #include "reboot_utils.h"
51 #include "selabel.h"
52 #include "selinux.h"
53 #else
54 #include "host_init_stubs.h"
55 #endif
56
57 using android::base::boot_clock;
58 using android::base::StartsWith;
59 using namespace std::literals::string_literals;
60
61 namespace android {
62 namespace init {
63
64 const std::string kDefaultAndroidDtDir("/proc/device-tree/firmware/android/");
65
66 void (*trigger_shutdown)(const std::string& command) = nullptr;
67
68 // DecodeUid() - decodes and returns the given string, which can be either the
69 // numeric or name representation, into the integer uid or gid.
DecodeUid(const std::string & name)70 Result<uid_t> DecodeUid(const std::string& name) {
71 if (isalpha(name[0])) {
72 passwd* pwd = getpwnam(name.c_str());
73 if (!pwd) return ErrnoError() << "getpwnam failed";
74
75 return pwd->pw_uid;
76 }
77
78 errno = 0;
79 uid_t result = static_cast<uid_t>(strtoul(name.c_str(), 0, 0));
80 if (errno) return ErrnoError() << "strtoul failed";
81
82 return result;
83 }
84
85 /*
86 * CreateSocket - creates a Unix domain socket in ANDROID_SOCKET_DIR
87 * ("/dev/socket") as dictated in init.rc. This socket is inherited by the
88 * daemon. We communicate the file descriptor's value via the environment
89 * variable ANDROID_SOCKET_ENV_PREFIX<name> ("ANDROID_SOCKET_foo").
90 */
CreateSocket(const std::string & name,int type,bool passcred,mode_t perm,uid_t uid,gid_t gid,const std::string & socketcon)91 Result<int> CreateSocket(const std::string& name, int type, bool passcred, mode_t perm, uid_t uid,
92 gid_t gid, const std::string& socketcon) {
93 if (!socketcon.empty()) {
94 if (setsockcreatecon(socketcon.c_str()) == -1) {
95 return ErrnoError() << "setsockcreatecon(\"" << socketcon << "\") failed";
96 }
97 }
98
99 android::base::unique_fd fd(socket(PF_UNIX, type, 0));
100 if (fd < 0) {
101 return ErrnoError() << "Failed to open socket '" << name << "'";
102 }
103
104 if (!socketcon.empty()) setsockcreatecon(nullptr);
105
106 struct sockaddr_un addr;
107 memset(&addr, 0 , sizeof(addr));
108 addr.sun_family = AF_UNIX;
109 snprintf(addr.sun_path, sizeof(addr.sun_path), ANDROID_SOCKET_DIR "/%s", name.c_str());
110
111 if ((unlink(addr.sun_path) != 0) && (errno != ENOENT)) {
112 return ErrnoError() << "Failed to unlink old socket '" << name << "'";
113 }
114
115 std::string secontext;
116 if (SelabelLookupFileContext(addr.sun_path, S_IFSOCK, &secontext) && !secontext.empty()) {
117 setfscreatecon(secontext.c_str());
118 }
119
120 if (passcred) {
121 int on = 1;
122 if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on))) {
123 return ErrnoError() << "Failed to set SO_PASSCRED '" << name << "'";
124 }
125 }
126
127 int ret = bind(fd, (struct sockaddr *) &addr, sizeof (addr));
128 int savederrno = errno;
129
130 if (!secontext.empty()) {
131 setfscreatecon(nullptr);
132 }
133
134 auto guard = android::base::make_scope_guard([&addr] { unlink(addr.sun_path); });
135
136 if (ret) {
137 errno = savederrno;
138 return ErrnoError() << "Failed to bind socket '" << name << "'";
139 }
140
141 if (lchown(addr.sun_path, uid, gid)) {
142 return ErrnoError() << "Failed to lchown socket '" << addr.sun_path << "'";
143 }
144 if (fchmodat(AT_FDCWD, addr.sun_path, perm, AT_SYMLINK_NOFOLLOW)) {
145 return ErrnoError() << "Failed to fchmodat socket '" << addr.sun_path << "'";
146 }
147
148 LOG(INFO) << "Created socket '" << addr.sun_path << "'"
149 << ", mode " << std::oct << perm << std::dec
150 << ", user " << uid
151 << ", group " << gid;
152
153 guard.Disable();
154 return fd.release();
155 }
156
ReadFile(const std::string & path)157 Result<std::string> ReadFile(const std::string& path) {
158 android::base::unique_fd fd(
159 TEMP_FAILURE_RETRY(open(path.c_str(), O_RDONLY | O_NOFOLLOW | O_CLOEXEC)));
160 if (fd == -1) {
161 return ErrnoError() << "open() failed";
162 }
163
164 // For security reasons, disallow world-writable
165 // or group-writable files.
166 struct stat sb;
167 if (fstat(fd, &sb) == -1) {
168 return ErrnoError() << "fstat failed()";
169 }
170 if ((sb.st_mode & (S_IWGRP | S_IWOTH)) != 0) {
171 return Error() << "Skipping insecure file";
172 }
173
174 std::string content;
175 if (!android::base::ReadFdToString(fd, &content)) {
176 return ErrnoError() << "Unable to read file contents";
177 }
178 return content;
179 }
180
OpenFile(const std::string & path,int flags,mode_t mode)181 static int OpenFile(const std::string& path, int flags, mode_t mode) {
182 std::string secontext;
183 if (SelabelLookupFileContext(path, mode, &secontext) && !secontext.empty()) {
184 setfscreatecon(secontext.c_str());
185 }
186
187 int rc = open(path.c_str(), flags, mode);
188
189 if (!secontext.empty()) {
190 int save_errno = errno;
191 setfscreatecon(nullptr);
192 errno = save_errno;
193 }
194
195 return rc;
196 }
197
WriteFile(const std::string & path,const std::string & content)198 Result<void> WriteFile(const std::string& path, const std::string& content) {
199 android::base::unique_fd fd(TEMP_FAILURE_RETRY(
200 OpenFile(path, O_WRONLY | O_CREAT | O_NOFOLLOW | O_TRUNC | O_CLOEXEC, 0600)));
201 if (fd == -1) {
202 return ErrnoError() << "open() failed";
203 }
204 if (!android::base::WriteStringToFd(content, fd)) {
205 return ErrnoError() << "Unable to write file contents";
206 }
207 return {};
208 }
209
mkdir_recursive(const std::string & path,mode_t mode)210 bool mkdir_recursive(const std::string& path, mode_t mode) {
211 std::string::size_type slash = 0;
212 while ((slash = path.find('/', slash + 1)) != std::string::npos) {
213 auto directory = path.substr(0, slash);
214 struct stat info;
215 if (stat(directory.c_str(), &info) != 0) {
216 auto ret = make_dir(directory, mode);
217 if (!ret && errno != EEXIST) return false;
218 }
219 }
220 auto ret = make_dir(path, mode);
221 if (!ret && errno != EEXIST) return false;
222 return true;
223 }
224
wait_for_file(const char * filename,std::chrono::nanoseconds timeout)225 int wait_for_file(const char* filename, std::chrono::nanoseconds timeout) {
226 android::base::Timer t;
227 while (t.duration() < timeout) {
228 struct stat sb;
229 if (stat(filename, &sb) != -1) {
230 LOG(INFO) << "wait for '" << filename << "' took " << t;
231 return 0;
232 }
233 std::this_thread::sleep_for(10ms);
234 }
235 LOG(WARNING) << "wait for '" << filename << "' timed out and took " << t;
236 return -1;
237 }
238
ImportKernelCmdline(const std::function<void (const std::string &,const std::string &)> & fn)239 void ImportKernelCmdline(const std::function<void(const std::string&, const std::string&)>& fn) {
240 std::string cmdline;
241 android::base::ReadFileToString("/proc/cmdline", &cmdline);
242
243 for (const auto& entry : android::base::Split(android::base::Trim(cmdline), " ")) {
244 std::vector<std::string> pieces = android::base::Split(entry, "=");
245 if (pieces.size() == 2) {
246 fn(pieces[0], pieces[1]);
247 }
248 }
249 }
250
make_dir(const std::string & path,mode_t mode)251 bool make_dir(const std::string& path, mode_t mode) {
252 std::string secontext;
253 if (SelabelLookupFileContext(path, mode, &secontext) && !secontext.empty()) {
254 setfscreatecon(secontext.c_str());
255 }
256
257 int rc = mkdir(path.c_str(), mode);
258
259 if (!secontext.empty()) {
260 int save_errno = errno;
261 setfscreatecon(nullptr);
262 errno = save_errno;
263 }
264
265 return rc == 0;
266 }
267
268 /*
269 * Returns true is pathname is a directory
270 */
is_dir(const char * pathname)271 bool is_dir(const char* pathname) {
272 struct stat info;
273 if (stat(pathname, &info) == -1) {
274 return false;
275 }
276 return S_ISDIR(info.st_mode);
277 }
278
ExpandProps(const std::string & src)279 Result<std::string> ExpandProps(const std::string& src) {
280 const char* src_ptr = src.c_str();
281
282 std::string dst;
283
284 /* - variables can either be $x.y or ${x.y}, in case they are only part
285 * of the string.
286 * - will accept $$ as a literal $.
287 * - no nested property expansion, i.e. ${foo.${bar}} is not supported,
288 * bad things will happen
289 * - ${x.y:-default} will return default value if property empty.
290 */
291 while (*src_ptr) {
292 const char* c;
293
294 c = strchr(src_ptr, '$');
295 if (!c) {
296 dst.append(src_ptr);
297 return dst;
298 }
299
300 dst.append(src_ptr, c);
301 c++;
302
303 if (*c == '$') {
304 dst.push_back(*(c++));
305 src_ptr = c;
306 continue;
307 } else if (*c == '\0') {
308 return dst;
309 }
310
311 std::string prop_name;
312 std::string def_val;
313 if (*c == '{') {
314 c++;
315 const char* end = strchr(c, '}');
316 if (!end) {
317 // failed to find closing brace, abort.
318 return Error() << "unexpected end of string in '" << src << "', looking for }";
319 }
320 prop_name = std::string(c, end);
321 c = end + 1;
322 size_t def = prop_name.find(":-");
323 if (def < prop_name.size()) {
324 def_val = prop_name.substr(def + 2);
325 prop_name = prop_name.substr(0, def);
326 }
327 } else {
328 prop_name = c;
329 if (SelinuxGetVendorAndroidVersion() >= __ANDROID_API_R__) {
330 return Error() << "using deprecated syntax for specifying property '" << c
331 << "', use ${name} instead";
332 } else {
333 LOG(ERROR) << "using deprecated syntax for specifying property '" << c
334 << "', use ${name} instead";
335 }
336 c += prop_name.size();
337 }
338
339 if (prop_name.empty()) {
340 return Error() << "invalid zero-length property name in '" << src << "'";
341 }
342
343 std::string prop_val = android::base::GetProperty(prop_name, "");
344 if (prop_val.empty()) {
345 if (def_val.empty()) {
346 return Error() << "property '" << prop_name << "' doesn't exist while expanding '"
347 << src << "'";
348 }
349 prop_val = def_val;
350 }
351
352 dst.append(prop_val);
353 src_ptr = c;
354 }
355
356 return dst;
357 }
358
init_android_dt_dir()359 static std::string init_android_dt_dir() {
360 // Use the standard procfs-based path by default
361 std::string android_dt_dir = kDefaultAndroidDtDir;
362 // The platform may specify a custom Android DT path in kernel cmdline
363 ImportKernelCmdline([&](const std::string& key, const std::string& value) {
364 if (key == "androidboot.android_dt_dir") {
365 android_dt_dir = value;
366 }
367 });
368 LOG(INFO) << "Using Android DT directory " << android_dt_dir;
369 return android_dt_dir;
370 }
371
372 // FIXME: The same logic is duplicated in system/core/fs_mgr/
get_android_dt_dir()373 const std::string& get_android_dt_dir() {
374 // Set once and saves time for subsequent calls to this function
375 static const std::string kAndroidDtDir = init_android_dt_dir();
376 return kAndroidDtDir;
377 }
378
379 // Reads the content of device tree file under the platform's Android DT directory.
380 // Returns true if the read is success, false otherwise.
read_android_dt_file(const std::string & sub_path,std::string * dt_content)381 bool read_android_dt_file(const std::string& sub_path, std::string* dt_content) {
382 const std::string file_name = get_android_dt_dir() + sub_path;
383 if (android::base::ReadFileToString(file_name, dt_content)) {
384 if (!dt_content->empty()) {
385 dt_content->pop_back(); // Trims the trailing '\0' out.
386 return true;
387 }
388 }
389 return false;
390 }
391
is_android_dt_value_expected(const std::string & sub_path,const std::string & expected_content)392 bool is_android_dt_value_expected(const std::string& sub_path, const std::string& expected_content) {
393 std::string dt_content;
394 if (read_android_dt_file(sub_path, &dt_content)) {
395 if (dt_content == expected_content) {
396 return true;
397 }
398 }
399 return false;
400 }
401
IsLegalPropertyName(const std::string & name)402 bool IsLegalPropertyName(const std::string& name) {
403 size_t namelen = name.size();
404
405 if (namelen < 1) return false;
406 if (name[0] == '.') return false;
407 if (name[namelen - 1] == '.') return false;
408
409 /* Only allow alphanumeric, plus '.', '-', '@', ':', or '_' */
410 /* Don't allow ".." to appear in a property name */
411 for (size_t i = 0; i < namelen; i++) {
412 if (name[i] == '.') {
413 // i=0 is guaranteed to never have a dot. See above.
414 if (name[i - 1] == '.') return false;
415 continue;
416 }
417 if (name[i] == '_' || name[i] == '-' || name[i] == '@' || name[i] == ':') continue;
418 if (name[i] >= 'a' && name[i] <= 'z') continue;
419 if (name[i] >= 'A' && name[i] <= 'Z') continue;
420 if (name[i] >= '0' && name[i] <= '9') continue;
421 return false;
422 }
423
424 return true;
425 }
426
IsLegalPropertyValue(const std::string & name,const std::string & value)427 Result<void> IsLegalPropertyValue(const std::string& name, const std::string& value) {
428 if (value.size() >= PROP_VALUE_MAX && !StartsWith(name, "ro.")) {
429 return Error() << "Property value too long";
430 }
431
432 if (mbstowcs(nullptr, value.data(), 0) == static_cast<std::size_t>(-1)) {
433 return Error() << "Value is not a UTF8 encoded string";
434 }
435
436 return {};
437 }
438
FscryptInferAction(const std::string & dir)439 static FscryptAction FscryptInferAction(const std::string& dir) {
440 const std::string prefix = "/data/";
441
442 if (!android::base::StartsWith(dir, prefix)) {
443 return FscryptAction::kNone;
444 }
445
446 // Special-case /data/media/obb per b/64566063
447 if (dir == "/data/media/obb") {
448 // Try to set policy on this directory, but if it is non-empty this may fail.
449 return FscryptAction::kAttempt;
450 }
451
452 // Only set policy on first level /data directories
453 // To make this less restrictive, consider using a policy file.
454 // However this is overkill for as long as the policy is simply
455 // to apply a global policy to all /data folders created via makedir
456 if (dir.find_first_of('/', prefix.size()) != std::string::npos) {
457 return FscryptAction::kNone;
458 }
459
460 // Special case various directories that must not be encrypted,
461 // often because their subdirectories must be encrypted.
462 // This isn't a nice way to do this, see b/26641735
463 std::vector<std::string> directories_to_exclude = {
464 "lost+found", "system_ce", "system_de", "misc_ce", "misc_de",
465 "vendor_ce", "vendor_de", "media", "data", "user",
466 "user_de", "apex", "preloads", "app-staging", "gsi",
467 };
468 for (const auto& d : directories_to_exclude) {
469 if ((prefix + d) == dir) {
470 return FscryptAction::kNone;
471 }
472 }
473 // Empty these directories if policy setting fails.
474 std::vector<std::string> wipe_on_failure = {
475 "rollback", "rollback-observer", // b/139193659
476 };
477 for (const auto& d : wipe_on_failure) {
478 if ((prefix + d) == dir) {
479 return FscryptAction::kDeleteIfNecessary;
480 }
481 }
482 return FscryptAction::kRequire;
483 }
484
ParseMkdir(const std::vector<std::string> & args)485 Result<MkdirOptions> ParseMkdir(const std::vector<std::string>& args) {
486 mode_t mode = 0755;
487 Result<uid_t> uid = -1;
488 Result<gid_t> gid = -1;
489 FscryptAction fscrypt_inferred_action = FscryptInferAction(args[1]);
490 FscryptAction fscrypt_action = fscrypt_inferred_action;
491 std::string ref_option = "ref";
492 bool set_option_encryption = false;
493 bool set_option_key = false;
494
495 for (size_t i = 2; i < args.size(); i++) {
496 switch (i) {
497 case 2:
498 mode = std::strtoul(args[2].c_str(), 0, 8);
499 break;
500 case 3:
501 uid = DecodeUid(args[3]);
502 if (!uid.ok()) {
503 return Error()
504 << "Unable to decode UID for '" << args[3] << "': " << uid.error();
505 }
506 break;
507 case 4:
508 gid = DecodeUid(args[4]);
509 if (!gid.ok()) {
510 return Error()
511 << "Unable to decode GID for '" << args[4] << "': " << gid.error();
512 }
513 break;
514 default:
515 auto parts = android::base::Split(args[i], "=");
516 if (parts.size() != 2) {
517 return Error() << "Can't parse option: '" << args[i] << "'";
518 }
519 auto optname = parts[0];
520 auto optval = parts[1];
521 if (optname == "encryption") {
522 if (set_option_encryption) {
523 return Error() << "Duplicated option: '" << optname << "'";
524 }
525 if (optval == "Require") {
526 fscrypt_action = FscryptAction::kRequire;
527 } else if (optval == "None") {
528 fscrypt_action = FscryptAction::kNone;
529 } else if (optval == "Attempt") {
530 fscrypt_action = FscryptAction::kAttempt;
531 } else if (optval == "DeleteIfNecessary") {
532 fscrypt_action = FscryptAction::kDeleteIfNecessary;
533 } else {
534 return Error() << "Unknown encryption option: '" << optval << "'";
535 }
536 set_option_encryption = true;
537 } else if (optname == "key") {
538 if (set_option_key) {
539 return Error() << "Duplicated option: '" << optname << "'";
540 }
541 if (optval == "ref" || optval == "per_boot_ref") {
542 ref_option = optval;
543 } else {
544 return Error() << "Unknown key option: '" << optval << "'";
545 }
546 set_option_key = true;
547 } else {
548 return Error() << "Unknown option: '" << args[i] << "'";
549 }
550 }
551 }
552 if (set_option_key && fscrypt_action == FscryptAction::kNone) {
553 return Error() << "Key option set but encryption action is none";
554 }
555 const std::string prefix = "/data/";
556 if (StartsWith(args[1], prefix) &&
557 args[1].find_first_of('/', prefix.size()) == std::string::npos) {
558 if (!set_option_encryption) {
559 LOG(WARNING) << "Top-level directory needs encryption action, eg mkdir " << args[1]
560 << " <mode> <uid> <gid> encryption=Require";
561 }
562 if (fscrypt_action == FscryptAction::kNone) {
563 LOG(INFO) << "Not setting encryption policy on: " << args[1];
564 }
565 }
566 if (fscrypt_action != fscrypt_inferred_action) {
567 LOG(WARNING) << "Inferred action different from explicit one, expected "
568 << static_cast<int>(fscrypt_inferred_action) << " but got "
569 << static_cast<int>(fscrypt_action);
570 }
571
572 return MkdirOptions{args[1], mode, *uid, *gid, fscrypt_action, ref_option};
573 }
574
ParseMountAll(const std::vector<std::string> & args)575 Result<MountAllOptions> ParseMountAll(const std::vector<std::string>& args) {
576 bool compat_mode = false;
577 bool import_rc = false;
578 if (SelinuxGetVendorAndroidVersion() <= __ANDROID_API_Q__) {
579 if (args.size() <= 1) {
580 return Error() << "mount_all requires at least 1 argument";
581 }
582 compat_mode = true;
583 import_rc = true;
584 }
585
586 std::size_t first_option_arg = args.size();
587 enum mount_mode mode = MOUNT_MODE_DEFAULT;
588
589 // If we are <= Q, then stop looking for non-fstab arguments at slot 2.
590 // Otherwise, stop looking at slot 1 (as the fstab path argument is optional >= R).
591 for (std::size_t na = args.size() - 1; na > (compat_mode ? 1 : 0); --na) {
592 if (args[na] == "--early") {
593 first_option_arg = na;
594 mode = MOUNT_MODE_EARLY;
595 } else if (args[na] == "--late") {
596 first_option_arg = na;
597 mode = MOUNT_MODE_LATE;
598 import_rc = false;
599 }
600 }
601
602 std::string fstab_path;
603 if (first_option_arg > 1) {
604 fstab_path = args[1];
605 } else if (compat_mode) {
606 return Error() << "mount_all argument 1 must be the fstab path";
607 }
608
609 std::vector<std::string> rc_paths;
610 for (std::size_t na = 2; na < first_option_arg; ++na) {
611 rc_paths.push_back(args[na]);
612 }
613
614 return MountAllOptions{rc_paths, fstab_path, mode, import_rc};
615 }
616
ParseRestorecon(const std::vector<std::string> & args)617 Result<std::pair<int, std::vector<std::string>>> ParseRestorecon(
618 const std::vector<std::string>& args) {
619 struct flag_type {
620 const char* name;
621 int value;
622 };
623 static const flag_type flags[] = {
624 {"--recursive", SELINUX_ANDROID_RESTORECON_RECURSE},
625 {"--skip-ce", SELINUX_ANDROID_RESTORECON_SKIPCE},
626 {"--cross-filesystems", SELINUX_ANDROID_RESTORECON_CROSS_FILESYSTEMS},
627 {0, 0}};
628
629 int flag = 0;
630 std::vector<std::string> paths;
631
632 bool in_flags = true;
633 for (size_t i = 1; i < args.size(); ++i) {
634 if (android::base::StartsWith(args[i], "--")) {
635 if (!in_flags) {
636 return Error() << "flags must precede paths";
637 }
638 bool found = false;
639 for (size_t j = 0; flags[j].name; ++j) {
640 if (args[i] == flags[j].name) {
641 flag |= flags[j].value;
642 found = true;
643 break;
644 }
645 }
646 if (!found) {
647 return Error() << "bad flag " << args[i];
648 }
649 } else {
650 in_flags = false;
651 paths.emplace_back(args[i]);
652 }
653 }
654 return std::pair(flag, paths);
655 }
656
ParseSwaponAll(const std::vector<std::string> & args)657 Result<std::string> ParseSwaponAll(const std::vector<std::string>& args) {
658 if (args.size() <= 1) {
659 if (SelinuxGetVendorAndroidVersion() <= __ANDROID_API_Q__) {
660 return Error() << "swapon_all requires at least 1 argument";
661 }
662 return {};
663 }
664 return args[1];
665 }
666
ParseUmountAll(const std::vector<std::string> & args)667 Result<std::string> ParseUmountAll(const std::vector<std::string>& args) {
668 if (args.size() <= 1) {
669 if (SelinuxGetVendorAndroidVersion() <= __ANDROID_API_Q__) {
670 return Error() << "umount_all requires at least 1 argument";
671 }
672 return {};
673 }
674 return args[1];
675 }
676
InitAborter(const char * abort_message)677 static void InitAborter(const char* abort_message) {
678 // When init forks, it continues to use this aborter for LOG(FATAL), but we want children to
679 // simply abort instead of trying to reboot the system.
680 if (getpid() != 1) {
681 android::base::DefaultAborter(abort_message);
682 return;
683 }
684
685 InitFatalReboot(SIGABRT);
686 }
687
688 // The kernel opens /dev/console and uses that fd for stdin/stdout/stderr if there is a serial
689 // console enabled and no initramfs, otherwise it does not provide any fds for stdin/stdout/stderr.
690 // SetStdioToDevNull() is used to close these existing fds if they exist and replace them with
691 // /dev/null regardless.
692 //
693 // In the case that these fds are provided by the kernel, the exec of second stage init causes an
694 // SELinux denial as it does not have access to /dev/console. In the case that they are not
695 // provided, exec of any further process is potentially dangerous as the first fd's opened by that
696 // process will take the stdin/stdout/stderr fileno's, which can cause issues if printf(), etc is
697 // then used by that process.
698 //
699 // Lastly, simply calling SetStdioToDevNull() in first stage init is not enough, since first
700 // stage init still runs in kernel context, future child processes will not have permissions to
701 // access any fds that it opens, including the one opened below for /dev/null. Therefore,
702 // SetStdioToDevNull() must be called again in second stage init.
SetStdioToDevNull(char ** argv)703 void SetStdioToDevNull(char** argv) {
704 // Make stdin/stdout/stderr all point to /dev/null.
705 int fd = open("/dev/null", O_RDWR); // NOLINT(android-cloexec-open)
706 if (fd == -1) {
707 int saved_errno = errno;
708 android::base::InitLogging(argv, &android::base::KernelLogger, InitAborter);
709 errno = saved_errno;
710 PLOG(FATAL) << "Couldn't open /dev/null";
711 }
712 dup2(fd, STDIN_FILENO);
713 dup2(fd, STDOUT_FILENO);
714 dup2(fd, STDERR_FILENO);
715 if (fd > STDERR_FILENO) close(fd);
716 }
717
InitKernelLogging(char ** argv)718 void InitKernelLogging(char** argv) {
719 SetFatalRebootTarget();
720 android::base::InitLogging(argv, &android::base::KernelLogger, InitAborter);
721 }
722
IsRecoveryMode()723 bool IsRecoveryMode() {
724 return access("/system/bin/recovery", F_OK) == 0;
725 }
726
727 // TODO(b/155203339): remove this
728 // Devices in the lab seem to be stuck during shutdown, but the logs don't capture the last actions
729 // before shutdown started, so we record those lines, ignoring requests to shutdown, and replay them
730 // if we identify that the device is stuck.
731 constexpr size_t kRecordedLogsSize = 30;
732 std::string recorded_logs[kRecordedLogsSize];
733 size_t recorded_log_position = 0;
734 std::mutex recorded_logs_lock;
735
InitSecondStageLogging(char ** argv)736 void InitSecondStageLogging(char** argv) {
737 SetFatalRebootTarget();
738 auto second_stage_logger = [](android::base::LogId log_id, android::base::LogSeverity severity,
739 const char* tag, const char* file, unsigned int line,
740 const char* message) {
741 // We only store logs for init, not its children, and only if they're not related to
742 // sys.powerctl.
743 if (getpid() == 1 && strstr(message, "sys.powerctl") == nullptr) {
744 auto lock = std::lock_guard{recorded_logs_lock};
745 recorded_logs[recorded_log_position++] = message;
746 if (recorded_log_position == kRecordedLogsSize) {
747 recorded_log_position = 0;
748 }
749 }
750 android::base::KernelLogger(log_id, severity, tag, file, line, message);
751 };
752 android::base::InitLogging(argv, second_stage_logger, InitAborter);
753 }
754
DumpShutdownDebugInformation()755 void DumpShutdownDebugInformation() {
756 auto lock = std::lock_guard{recorded_logs_lock};
757 android::base::KernelLogger(
758 android::base::MAIN, android::base::ERROR, "init", nullptr, 0,
759 "===================== Dumping previous init lines =====================");
760 for (size_t i = recorded_log_position; i < kRecordedLogsSize; ++i) {
761 android::base::KernelLogger(android::base::MAIN, android::base::ERROR, "init", nullptr, 0,
762 recorded_logs[i].c_str());
763 }
764 for (size_t i = 0; i < recorded_log_position; ++i) {
765 android::base::KernelLogger(android::base::MAIN, android::base::ERROR, "init", nullptr, 0,
766 recorded_logs[i].c_str());
767 }
768 android::base::KernelLogger(android::base::MAIN, android::base::ERROR, "init", nullptr, 0,
769 "===================== End of dump =====================");
770 }
771
772 } // namespace init
773 } // namespace android
774