1 /*
2 * Copyright (C) 2020 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 "first_stage_console.h"
18
19 #include <stdio.h>
20 #include <sys/stat.h>
21 #include <sys/sysmacros.h>
22 #include <sys/types.h>
23 #include <sys/wait.h>
24 #include <termios.h>
25
26 #include <string>
27 #include <thread>
28
29 #include <android-base/chrono_utils.h>
30 #include <android-base/file.h>
31 #include <android-base/logging.h>
32
KernelConsolePresent(const std::string & cmdline)33 static bool KernelConsolePresent(const std::string& cmdline) {
34 size_t pos = 0;
35 while (true) {
36 pos = cmdline.find("console=", pos);
37 if (pos == std::string::npos) return false;
38 if (pos == 0 || cmdline[pos - 1] == ' ') return true;
39 pos++;
40 }
41 }
42
SetupConsole()43 static bool SetupConsole() {
44 if (mknod("/dev/console", S_IFCHR | 0600, makedev(5, 1))) {
45 PLOG(ERROR) << "unable to create /dev/console";
46 return false;
47 }
48 int fd = -1;
49 int tries = 50; // should timeout after 5s
50 // The device driver for console may not be ready yet so retry for a while in case of failure.
51 while (tries--) {
52 fd = open("/dev/console", O_RDWR);
53 if (fd != -1) break;
54 std::this_thread::sleep_for(100ms);
55 }
56 if (fd == -1) {
57 PLOG(ERROR) << "could not open /dev/console";
58 return false;
59 }
60 ioctl(fd, TIOCSCTTY, 0);
61 dup2(fd, STDIN_FILENO);
62 dup2(fd, STDOUT_FILENO);
63 dup2(fd, STDERR_FILENO);
64 close(fd);
65 return true;
66 }
67
RunScript()68 static void RunScript() {
69 LOG(INFO) << "Attempting to run /first_stage.sh...";
70 pid_t pid = fork();
71 if (pid != 0) {
72 int status;
73 waitpid(pid, &status, 0);
74 LOG(INFO) << "/first_stage.sh exited with status " << status;
75 return;
76 }
77 const char* path = "/system/bin/sh";
78 const char* args[] = {path, "/first_stage.sh", nullptr};
79 int rv = execv(path, const_cast<char**>(args));
80 LOG(ERROR) << "unable to execv /first_stage.sh, returned " << rv << " errno " << errno;
81 }
82
83 namespace android {
84 namespace init {
85
StartConsole(const std::string & cmdline)86 void StartConsole(const std::string& cmdline) {
87 bool console = KernelConsolePresent(cmdline);
88
89 pid_t pid = fork();
90 if (pid != 0) {
91 int status;
92 waitpid(pid, &status, 0);
93 LOG(ERROR) << "console shell exited with status " << status;
94 return;
95 }
96
97 if (console) console = SetupConsole();
98 RunScript();
99 if (console) {
100 const char* path = "/system/bin/sh";
101 const char* args[] = {path, nullptr};
102 int rv = execv(path, const_cast<char**>(args));
103 LOG(ERROR) << "unable to execv, returned " << rv << " errno " << errno;
104 }
105 _exit(127);
106 }
107
FirstStageConsole(const std::string & cmdline,const std::string & bootconfig)108 int FirstStageConsole(const std::string& cmdline, const std::string& bootconfig) {
109 auto pos = bootconfig.find("androidboot.first_stage_console =");
110 if (pos != std::string::npos) {
111 int val = 0;
112 if (sscanf(bootconfig.c_str() + pos, "androidboot.first_stage_console = \"%d\"", &val) !=
113 1) {
114 return FirstStageConsoleParam::DISABLED;
115 }
116 if (val <= FirstStageConsoleParam::MAX_PARAM_VALUE && val >= 0) {
117 return val;
118 }
119 }
120
121 pos = cmdline.find("androidboot.first_stage_console=");
122 if (pos != std::string::npos) {
123 int val = 0;
124 if (sscanf(cmdline.c_str() + pos, "androidboot.first_stage_console=%d", &val) != 1) {
125 return FirstStageConsoleParam::DISABLED;
126 }
127 if (val <= FirstStageConsoleParam::MAX_PARAM_VALUE && val >= 0) {
128 return val;
129 }
130 }
131 return FirstStageConsoleParam::DISABLED;
132 }
133
134 } // namespace init
135 } // namespace android
136