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