| /* |
| * Copyright (C) 2015 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| // Functionality for launching and managing shell subprocesses. |
| // |
| // There are two types of subprocesses, PTY or raw. PTY is typically used for |
| // an interactive session, raw for non-interactive. There are also two methods |
| // of communication with the subprocess, passing raw data or using a simple |
| // protocol to wrap packets. The protocol allows separating stdout/stderr and |
| // passing the exit code back, but is not backwards compatible. |
| // ----------------+-------------------------------------- |
| // Type Protocol | Exit code? Separate stdout/stderr? |
| // ----------------+-------------------------------------- |
| // PTY No | No No |
| // Raw No | No No |
| // PTY Yes | Yes No |
| // Raw Yes | Yes Yes |
| // ----------------+-------------------------------------- |
| // |
| // Non-protocol subprocesses work by passing subprocess stdin/out/err through |
| // a single pipe which is registered with a local socket in adbd. The local |
| // socket uses the fdevent loop to pass raw data between this pipe and the |
| // transport, which then passes data back to the adb client. Cleanup is done by |
| // waiting in a separate thread for the subprocesses to exit and then signaling |
| // a separate fdevent to close out the local socket from the main loop. |
| // |
| // ------------------+-------------------------+------------------------------ |
| // Subprocess | adbd subprocess thread | adbd main fdevent loop |
| // ------------------+-------------------------+------------------------------ |
| // | | |
| // stdin/out/err <-----------------------------> LocalSocket |
| // | | | |
| // | | Block on exit | |
| // | | * | |
| // v | * | |
| // Exit ---> Unblock | |
| // | | | |
| // | v | |
| // | Notify shell exit FD ---> Close LocalSocket |
| // ------------------+-------------------------+------------------------------ |
| // |
| // The protocol requires the thread to intercept stdin/out/err in order to |
| // wrap/unwrap data with shell protocol packets. |
| // |
| // ------------------+-------------------------+------------------------------ |
| // Subprocess | adbd subprocess thread | adbd main fdevent loop |
| // ------------------+-------------------------+------------------------------ |
| // | | |
| // stdin/out <---> Protocol <---> LocalSocket |
| // stderr ---> Protocol ---> LocalSocket |
| // | | | |
| // v | | |
| // Exit ---> Exit code protocol ---> LocalSocket |
| // | | | |
| // | v | |
| // | Notify shell exit FD ---> Close LocalSocket |
| // ------------------+-------------------------+------------------------------ |
| // |
| // An alternate approach is to put the protocol wrapping/unwrapping in the main |
| // fdevent loop, which has the advantage of being able to re-use the existing |
| // select() code for handling data streams. However, implementation turned out |
| // to be more complex due to partial reads and non-blocking I/O so this model |
| // was chosen instead. |
| |
| #define TRACE_TAG SHELL |
| |
| #include "sysdeps.h" |
| |
| #include "shell_service.h" |
| |
| #include <errno.h> |
| #include <paths.h> |
| #include <pty.h> |
| #include <pwd.h> |
| #include <sys/select.h> |
| #include <termios.h> |
| |
| #include <memory> |
| #include <string> |
| #include <thread> |
| #include <unordered_map> |
| #include <vector> |
| |
| #include <android-base/logging.h> |
| #include <android-base/properties.h> |
| #include <android-base/stringprintf.h> |
| #include <private/android_logger.h> |
| |
| #if defined(__ANDROID__) |
| #include <selinux/android.h> |
| #endif |
| |
| #include "adb.h" |
| #include "adb_io.h" |
| #include "adb_trace.h" |
| #include "adb_unique_fd.h" |
| #include "adb_utils.h" |
| #include "security_log_tags.h" |
| #include "shell_protocol.h" |
| |
| namespace { |
| |
| // Reads from |fd| until close or failure. |
| std::string ReadAll(borrowed_fd fd) { |
| char buffer[512]; |
| std::string received; |
| |
| while (1) { |
| int bytes = adb_read(fd, buffer, sizeof(buffer)); |
| if (bytes <= 0) { |
| break; |
| } |
| received.append(buffer, bytes); |
| } |
| |
| return received; |
| } |
| |
| // Creates a socketpair and saves the endpoints to |fd1| and |fd2|. |
| bool CreateSocketpair(unique_fd* fd1, unique_fd* fd2) { |
| int sockets[2]; |
| if (adb_socketpair(sockets) < 0) { |
| PLOG(ERROR) << "cannot create socket pair"; |
| return false; |
| } |
| fd1->reset(sockets[0]); |
| fd2->reset(sockets[1]); |
| return true; |
| } |
| |
| class Subprocess { |
| public: |
| Subprocess(std::string command, const char* terminal_type, SubprocessType type, |
| SubprocessProtocol protocol, bool make_pty_raw); |
| ~Subprocess(); |
| |
| const std::string& command() const { return command_; } |
| |
| int ReleaseLocalSocket() { return local_socket_sfd_.release(); } |
| |
| pid_t pid() const { return pid_; } |
| |
| // Sets up FDs, forks a subprocess, starts the subprocess manager thread, |
| // and exec's the child. Returns false and sets error on failure. |
| bool ForkAndExec(std::string* _Nonnull error); |
| |
| // Sets up FDs, starts a thread executing command and the manager thread, |
| // Returns false and sets error on failure. |
| bool ExecInProcess(Command command, std::string* _Nonnull error); |
| |
| // Start the subprocess manager thread. Consumes the subprocess, regardless of success. |
| // Returns false and sets error on failure. |
| static bool StartThread(std::unique_ptr<Subprocess> subprocess, |
| std::string* _Nonnull error); |
| |
| private: |
| // Opens the file at |pts_name|. |
| int OpenPtyChildFd(const char* pts_name, unique_fd* error_sfd); |
| |
| bool ConnectProtocolEndpoints(std::string* _Nonnull error); |
| |
| static void ThreadHandler(void* userdata); |
| void PassDataStreams(); |
| void WaitForExit(); |
| |
| unique_fd* SelectLoop(fd_set* master_read_set_ptr, |
| fd_set* master_write_set_ptr); |
| |
| // Input/output stream handlers. Success returns nullptr, failure returns |
| // a pointer to the failed FD. |
| unique_fd* PassInput(); |
| unique_fd* PassOutput(unique_fd* sfd, ShellProtocol::Id id); |
| |
| const std::string command_; |
| const std::string terminal_type_; |
| SubprocessType type_; |
| SubprocessProtocol protocol_; |
| bool make_pty_raw_; |
| pid_t pid_ = -1; |
| unique_fd local_socket_sfd_; |
| |
| // Shell protocol variables. |
| unique_fd stdinout_sfd_, stderr_sfd_, protocol_sfd_; |
| std::unique_ptr<ShellProtocol> input_, output_; |
| size_t input_bytes_left_ = 0; |
| |
| DISALLOW_COPY_AND_ASSIGN(Subprocess); |
| }; |
| |
| Subprocess::Subprocess(std::string command, const char* terminal_type, SubprocessType type, |
| SubprocessProtocol protocol, bool make_pty_raw) |
| : command_(std::move(command)), |
| terminal_type_(terminal_type ? terminal_type : ""), |
| type_(type), |
| protocol_(protocol), |
| make_pty_raw_(make_pty_raw) {} |
| |
| Subprocess::~Subprocess() { |
| WaitForExit(); |
| } |
| |
| static std::string GetHostName() { |
| char buf[HOST_NAME_MAX]; |
| if (gethostname(buf, sizeof(buf)) != -1 && strcmp(buf, "localhost") != 0) return buf; |
| |
| return android::base::GetProperty("ro.product.device", "android"); |
| } |
| |
| bool Subprocess::ForkAndExec(std::string* error) { |
| unique_fd child_stdinout_sfd, child_stderr_sfd; |
| unique_fd parent_error_sfd, child_error_sfd; |
| char pts_name[PATH_MAX]; |
| |
| if (command_.empty()) { |
| __android_log_security_bswrite(SEC_TAG_ADB_SHELL_INTERACTIVE, ""); |
| } else { |
| __android_log_security_bswrite(SEC_TAG_ADB_SHELL_CMD, command_.c_str()); |
| } |
| |
| // Create a socketpair for the fork() child to report any errors back to the parent. Since we |
| // use threads, logging directly from the child might deadlock due to locks held in another |
| // thread during the fork. |
| if (!CreateSocketpair(&parent_error_sfd, &child_error_sfd)) { |
| *error = android::base::StringPrintf( |
| "failed to create pipe for subprocess error reporting: %s", strerror(errno)); |
| return false; |
| } |
| |
| // Construct the environment for the child before we fork. |
| passwd* pw = getpwuid(getuid()); |
| std::unordered_map<std::string, std::string> env; |
| if (environ) { |
| char** current = environ; |
| while (char* env_cstr = *current++) { |
| std::string env_string = env_cstr; |
| char* delimiter = strchr(&env_string[0], '='); |
| |
| // Drop any values that don't contain '='. |
| if (delimiter) { |
| *delimiter++ = '\0'; |
| env[env_string.c_str()] = delimiter; |
| } |
| } |
| } |
| |
| if (pw != nullptr) { |
| env["HOME"] = pw->pw_dir; |
| env["HOSTNAME"] = GetHostName(); |
| env["LOGNAME"] = pw->pw_name; |
| env["SHELL"] = pw->pw_shell; |
| env["TMPDIR"] = "/data/local/tmp"; |
| env["USER"] = pw->pw_name; |
| } |
| |
| if (!terminal_type_.empty()) { |
| env["TERM"] = terminal_type_; |
| } |
| |
| std::vector<std::string> joined_env; |
| for (const auto& it : env) { |
| const char* key = it.first.c_str(); |
| const char* value = it.second.c_str(); |
| joined_env.push_back(android::base::StringPrintf("%s=%s", key, value)); |
| } |
| |
| std::vector<const char*> cenv; |
| for (const std::string& str : joined_env) { |
| cenv.push_back(str.c_str()); |
| } |
| cenv.push_back(nullptr); |
| |
| if (type_ == SubprocessType::kPty) { |
| int fd; |
| pid_ = forkpty(&fd, pts_name, nullptr, nullptr); |
| if (pid_ > 0) { |
| stdinout_sfd_.reset(fd); |
| } |
| } else { |
| if (!CreateSocketpair(&stdinout_sfd_, &child_stdinout_sfd)) { |
| *error = android::base::StringPrintf("failed to create socketpair for stdin/out: %s", |
| strerror(errno)); |
| return false; |
| } |
| // Raw subprocess + shell protocol allows for splitting stderr. |
| if (protocol_ == SubprocessProtocol::kShell && |
| !CreateSocketpair(&stderr_sfd_, &child_stderr_sfd)) { |
| *error = android::base::StringPrintf("failed to create socketpair for stderr: %s", |
| strerror(errno)); |
| return false; |
| } |
| pid_ = fork(); |
| } |
| |
| if (pid_ == -1) { |
| *error = android::base::StringPrintf("fork failed: %s", strerror(errno)); |
| return false; |
| } |
| |
| if (pid_ == 0) { |
| // Subprocess child. |
| setsid(); |
| |
| if (type_ == SubprocessType::kPty) { |
| child_stdinout_sfd.reset(OpenPtyChildFd(pts_name, &child_error_sfd)); |
| } |
| |
| dup2(child_stdinout_sfd.get(), STDIN_FILENO); |
| dup2(child_stdinout_sfd.get(), STDOUT_FILENO); |
| dup2(child_stderr_sfd != -1 ? child_stderr_sfd.get() : child_stdinout_sfd.get(), |
| STDERR_FILENO); |
| |
| // exec doesn't trigger destructors, close the FDs manually. |
| stdinout_sfd_.reset(-1); |
| stderr_sfd_.reset(-1); |
| child_stdinout_sfd.reset(-1); |
| child_stderr_sfd.reset(-1); |
| parent_error_sfd.reset(-1); |
| close_on_exec(child_error_sfd); |
| |
| // adbd sets SIGPIPE to SIG_IGN to get EPIPE instead, and Linux propagates that to child |
| // processes, so we need to manually reset back to SIG_DFL here (http://b/35209888). |
| signal(SIGPIPE, SIG_DFL); |
| |
| // Increase oom_score_adj from -1000, so that the child is visible to the OOM-killer. |
| // Don't treat failure as an error, because old Android kernels explicitly disabled this. |
| int oom_score_adj_fd = adb_open("/proc/self/oom_score_adj", O_WRONLY | O_CLOEXEC); |
| if (oom_score_adj_fd != -1) { |
| const char* oom_score_adj_value = "-950"; |
| TEMP_FAILURE_RETRY( |
| adb_write(oom_score_adj_fd, oom_score_adj_value, strlen(oom_score_adj_value))); |
| } |
| |
| #ifdef __ANDROID_RECOVERY__ |
| // Special routine for recovery. Switch to shell domain when adbd is |
| // is running with dropped privileged (i.e. not running as root) and |
| // is built for the recovery mode. This is required because recovery |
| // rootfs is not labeled and everything is labeled just as rootfs. |
| char* con = nullptr; |
| if (getcon(&con) == 0) { |
| if (!strcmp(con, "u:r:adbd:s0")) { |
| if (selinux_android_setcon("u:r:shell:s0") < 0) { |
| LOG(FATAL) << "Could not set SELinux context for subprocess"; |
| } |
| } |
| freecon(con); |
| } else { |
| LOG(FATAL) << "Failed to get SELinux context"; |
| } |
| #endif |
| |
| if (command_.empty()) { |
| // Spawn a login shell if we don't have a command. |
| execle(_PATH_BSHELL, "-" _PATH_BSHELL, nullptr, cenv.data()); |
| } else { |
| execle(_PATH_BSHELL, _PATH_BSHELL, "-c", command_.c_str(), nullptr, cenv.data()); |
| } |
| WriteFdExactly(child_error_sfd, "exec '" _PATH_BSHELL "' failed: "); |
| WriteFdExactly(child_error_sfd, strerror(errno)); |
| child_error_sfd.reset(-1); |
| _Exit(1); |
| } |
| |
| // Subprocess parent. |
| D("subprocess parent: stdin/stdout FD = %d, stderr FD = %d", |
| stdinout_sfd_.get(), stderr_sfd_.get()); |
| |
| // Wait to make sure the subprocess exec'd without error. |
| child_error_sfd.reset(-1); |
| std::string error_message = ReadAll(parent_error_sfd); |
| if (!error_message.empty()) { |
| *error = error_message; |
| return false; |
| } |
| |
| D("subprocess parent: exec completed"); |
| if (!ConnectProtocolEndpoints(error)) { |
| kill(pid_, SIGKILL); |
| return false; |
| } |
| |
| D("subprocess parent: completed"); |
| return true; |
| } |
| |
| bool Subprocess::ExecInProcess(Command command, std::string* _Nonnull error) { |
| unique_fd child_stdinout_sfd, child_stderr_sfd; |
| |
| CHECK(type_ == SubprocessType::kRaw); |
| |
| __android_log_security_bswrite(SEC_TAG_ADB_SHELL_CMD, command_.c_str()); |
| |
| if (!CreateSocketpair(&stdinout_sfd_, &child_stdinout_sfd)) { |
| *error = android::base::StringPrintf("failed to create socketpair for stdin/out: %s", |
| strerror(errno)); |
| return false; |
| } |
| if (protocol_ == SubprocessProtocol::kShell) { |
| // Shell protocol allows for splitting stderr. |
| if (!CreateSocketpair(&stderr_sfd_, &child_stderr_sfd)) { |
| *error = android::base::StringPrintf("failed to create socketpair for stderr: %s", |
| strerror(errno)); |
| return false; |
| } |
| } else { |
| // Raw protocol doesn't support multiple output streams, so combine stdout and stderr. |
| child_stderr_sfd.reset(dup(child_stdinout_sfd.get())); |
| } |
| |
| D("execinprocess: stdin/stdout FD = %d, stderr FD = %d", stdinout_sfd_.get(), |
| stderr_sfd_.get()); |
| |
| if (!ConnectProtocolEndpoints(error)) { |
| return false; |
| } |
| |
| std::thread([inout_sfd = std::move(child_stdinout_sfd), err_sfd = std::move(child_stderr_sfd), |
| command = std::move(command), |
| args = command_]() { command(args, inout_sfd, inout_sfd, err_sfd); }) |
| .detach(); |
| |
| D("execinprocess: completed"); |
| return true; |
| } |
| |
| bool Subprocess::ConnectProtocolEndpoints(std::string* _Nonnull error) { |
| if (protocol_ == SubprocessProtocol::kNone) { |
| // No protocol: all streams pass through the stdinout FD and hook |
| // directly into the local socket for raw data transfer. |
| local_socket_sfd_.reset(stdinout_sfd_.release()); |
| } else { |
| // Required for shell protocol: create another socketpair to intercept data. |
| if (!CreateSocketpair(&protocol_sfd_, &local_socket_sfd_)) { |
| *error = android::base::StringPrintf( |
| "failed to create socketpair to intercept data: %s", strerror(errno)); |
| return false; |
| } |
| D("protocol FD = %d", protocol_sfd_.get()); |
| |
| input_ = std::make_unique<ShellProtocol>(protocol_sfd_); |
| output_ = std::make_unique<ShellProtocol>(protocol_sfd_); |
| if (!input_ || !output_) { |
| *error = "failed to allocate shell protocol objects"; |
| return false; |
| } |
| |
| // Don't let reads/writes to the subprocess block our thread. This isn't |
| // likely but could happen under unusual circumstances, such as if we |
| // write a ton of data to stdin but the subprocess never reads it and |
| // the pipe fills up. |
| for (int fd : {stdinout_sfd_.get(), stderr_sfd_.get()}) { |
| if (fd >= 0) { |
| if (!set_file_block_mode(fd, false)) { |
| *error = android::base::StringPrintf( |
| "failed to set non-blocking mode for fd %d", fd); |
| return false; |
| } |
| } |
| } |
| } |
| |
| return true; |
| } |
| |
| bool Subprocess::StartThread(std::unique_ptr<Subprocess> subprocess, std::string* error) { |
| Subprocess* raw = subprocess.release(); |
| std::thread(ThreadHandler, raw).detach(); |
| |
| return true; |
| } |
| |
| int Subprocess::OpenPtyChildFd(const char* pts_name, unique_fd* error_sfd) { |
| int child_fd = adb_open(pts_name, O_RDWR | O_CLOEXEC); |
| if (child_fd == -1) { |
| // Don't use WriteFdFmt; since we're in the fork() child we don't want |
| // to allocate any heap memory to avoid race conditions. |
| const char* messages[] = {"child failed to open pseudo-term slave ", |
| pts_name, ": ", strerror(errno)}; |
| for (const char* message : messages) { |
| WriteFdExactly(*error_sfd, message); |
| } |
| abort(); |
| } |
| |
| if (make_pty_raw_) { |
| termios tattr; |
| if (tcgetattr(child_fd, &tattr) == -1) { |
| int saved_errno = errno; |
| WriteFdExactly(*error_sfd, "tcgetattr failed: "); |
| WriteFdExactly(*error_sfd, strerror(saved_errno)); |
| abort(); |
| } |
| |
| cfmakeraw(&tattr); |
| if (tcsetattr(child_fd, TCSADRAIN, &tattr) == -1) { |
| int saved_errno = errno; |
| WriteFdExactly(*error_sfd, "tcsetattr failed: "); |
| WriteFdExactly(*error_sfd, strerror(saved_errno)); |
| abort(); |
| } |
| } |
| |
| return child_fd; |
| } |
| |
| void Subprocess::ThreadHandler(void* userdata) { |
| Subprocess* subprocess = reinterpret_cast<Subprocess*>(userdata); |
| |
| adb_thread_setname(android::base::StringPrintf("shell svc %d", subprocess->pid())); |
| |
| D("passing data streams for PID %d", subprocess->pid()); |
| subprocess->PassDataStreams(); |
| |
| D("deleting Subprocess for PID %d", subprocess->pid()); |
| delete subprocess; |
| } |
| |
| void Subprocess::PassDataStreams() { |
| if (protocol_sfd_ == -1) { |
| return; |
| } |
| |
| // Start by trying to read from the protocol FD, stdout, and stderr. |
| fd_set master_read_set, master_write_set; |
| FD_ZERO(&master_read_set); |
| FD_ZERO(&master_write_set); |
| for (unique_fd* sfd : {&protocol_sfd_, &stdinout_sfd_, &stderr_sfd_}) { |
| if (*sfd != -1) { |
| FD_SET(sfd->get(), &master_read_set); |
| } |
| } |
| |
| // Pass data until the protocol FD or both the subprocess pipes die, at |
| // which point we can't pass any more data. |
| while (protocol_sfd_ != -1 && (stdinout_sfd_ != -1 || stderr_sfd_ != -1)) { |
| unique_fd* dead_sfd = SelectLoop(&master_read_set, &master_write_set); |
| if (dead_sfd) { |
| D("closing FD %d", dead_sfd->get()); |
| FD_CLR(dead_sfd->get(), &master_read_set); |
| FD_CLR(dead_sfd->get(), &master_write_set); |
| if (dead_sfd == &protocol_sfd_) { |
| // Using SIGHUP is a decent general way to indicate that the |
| // controlling process is going away. If specific signals are |
| // needed (e.g. SIGINT), pass those through the shell protocol |
| // and only fall back on this for unexpected closures. |
| D("protocol FD died, sending SIGHUP to pid %d", pid_); |
| if (pid_ != -1) { |
| kill(pid_, SIGHUP); |
| } |
| |
| // We also need to close the pipes connected to the child process |
| // so that if it ignores SIGHUP and continues to write data it |
| // won't fill up the pipe and block. |
| stdinout_sfd_.reset(); |
| stderr_sfd_.reset(); |
| } |
| dead_sfd->reset(); |
| } |
| } |
| } |
| |
| namespace { |
| |
| inline bool ValidAndInSet(const unique_fd& sfd, fd_set* set) { |
| return sfd != -1 && FD_ISSET(sfd.get(), set); |
| } |
| |
| } // namespace |
| |
| unique_fd* Subprocess::SelectLoop(fd_set* master_read_set_ptr, |
| fd_set* master_write_set_ptr) { |
| fd_set read_set, write_set; |
| int select_n = |
| std::max(std::max(protocol_sfd_.get(), stdinout_sfd_.get()), stderr_sfd_.get()) + 1; |
| unique_fd* dead_sfd = nullptr; |
| |
| // Keep calling select() and passing data until an FD closes/errors. |
| while (!dead_sfd) { |
| memcpy(&read_set, master_read_set_ptr, sizeof(read_set)); |
| memcpy(&write_set, master_write_set_ptr, sizeof(write_set)); |
| if (select(select_n, &read_set, &write_set, nullptr, nullptr) < 0) { |
| if (errno == EINTR) { |
| continue; |
| } else { |
| PLOG(ERROR) << "select failed, closing subprocess pipes"; |
| stdinout_sfd_.reset(-1); |
| stderr_sfd_.reset(-1); |
| return nullptr; |
| } |
| } |
| |
| // Read stdout, write to protocol FD. |
| if (ValidAndInSet(stdinout_sfd_, &read_set)) { |
| dead_sfd = PassOutput(&stdinout_sfd_, ShellProtocol::kIdStdout); |
| } |
| |
| // Read stderr, write to protocol FD. |
| if (!dead_sfd && ValidAndInSet(stderr_sfd_, &read_set)) { |
| dead_sfd = PassOutput(&stderr_sfd_, ShellProtocol::kIdStderr); |
| } |
| |
| // Read protocol FD, write to stdin. |
| if (!dead_sfd && ValidAndInSet(protocol_sfd_, &read_set)) { |
| dead_sfd = PassInput(); |
| // If we didn't finish writing, block on stdin write. |
| if (input_bytes_left_) { |
| FD_CLR(protocol_sfd_.get(), master_read_set_ptr); |
| FD_SET(stdinout_sfd_.get(), master_write_set_ptr); |
| } |
| } |
| |
| // Continue writing to stdin; only happens if a previous write blocked. |
| if (!dead_sfd && ValidAndInSet(stdinout_sfd_, &write_set)) { |
| dead_sfd = PassInput(); |
| // If we finished writing, go back to blocking on protocol read. |
| if (!input_bytes_left_) { |
| FD_SET(protocol_sfd_.get(), master_read_set_ptr); |
| FD_CLR(stdinout_sfd_.get(), master_write_set_ptr); |
| } |
| } |
| } // while (!dead_sfd) |
| |
| return dead_sfd; |
| } |
| |
| unique_fd* Subprocess::PassInput() { |
| // Only read a new packet if we've finished writing the last one. |
| if (!input_bytes_left_) { |
| if (!input_->Read()) { |
| // Read() uses ReadFdExactly() which sets errno to 0 on EOF. |
| if (errno != 0) { |
| PLOG(ERROR) << "error reading protocol FD " << protocol_sfd_.get(); |
| } |
| return &protocol_sfd_; |
| } |
| |
| if (stdinout_sfd_ != -1) { |
| switch (input_->id()) { |
| case ShellProtocol::kIdWindowSizeChange: |
| int rows, cols, x_pixels, y_pixels; |
| if (sscanf(input_->data(), "%dx%d,%dx%d", |
| &rows, &cols, &x_pixels, &y_pixels) == 4) { |
| winsize ws; |
| ws.ws_row = rows; |
| ws.ws_col = cols; |
| ws.ws_xpixel = x_pixels; |
| ws.ws_ypixel = y_pixels; |
| ioctl(stdinout_sfd_.get(), TIOCSWINSZ, &ws); |
| } |
| break; |
| case ShellProtocol::kIdStdin: |
| input_bytes_left_ = input_->data_length(); |
| break; |
| case ShellProtocol::kIdCloseStdin: |
| if (type_ == SubprocessType::kRaw) { |
| if (adb_shutdown(stdinout_sfd_, SHUT_WR) == 0) { |
| return nullptr; |
| } |
| PLOG(ERROR) << "failed to shutdown writes to FD " << stdinout_sfd_.get(); |
| return &stdinout_sfd_; |
| } else { |
| // PTYs can't close just input, so rather than close the |
| // FD and risk losing subprocess output, leave it open. |
| // This only happens if the client starts a PTY shell |
| // non-interactively which is rare and unsupported. |
| // If necessary, the client can manually close the shell |
| // with `exit` or by killing the adb client process. |
| D("can't close input for PTY FD %d", stdinout_sfd_.get()); |
| } |
| break; |
| } |
| } |
| } |
| |
| if (input_bytes_left_ > 0) { |
| int index = input_->data_length() - input_bytes_left_; |
| int bytes = adb_write(stdinout_sfd_, input_->data() + index, input_bytes_left_); |
| if (bytes == 0 || (bytes < 0 && errno != EAGAIN)) { |
| if (bytes < 0) { |
| PLOG(ERROR) << "error reading stdin FD " << stdinout_sfd_.get(); |
| } |
| // stdin is done, mark this packet as finished and we'll just start |
| // dumping any further data received from the protocol FD. |
| input_bytes_left_ = 0; |
| return &stdinout_sfd_; |
| } else if (bytes > 0) { |
| input_bytes_left_ -= bytes; |
| } |
| } |
| |
| return nullptr; |
| } |
| |
| unique_fd* Subprocess::PassOutput(unique_fd* sfd, ShellProtocol::Id id) { |
| int bytes = adb_read(*sfd, output_->data(), output_->data_capacity()); |
| if (bytes == 0 || (bytes < 0 && errno != EAGAIN)) { |
| // read() returns EIO if a PTY closes; don't report this as an error, |
| // it just means the subprocess completed. |
| if (bytes < 0 && !(type_ == SubprocessType::kPty && errno == EIO)) { |
| PLOG(ERROR) << "error reading output FD " << sfd->get(); |
| } |
| return sfd; |
| } |
| |
| if (bytes > 0 && !output_->Write(id, bytes)) { |
| if (errno != 0) { |
| PLOG(ERROR) << "error reading protocol FD " << protocol_sfd_.get(); |
| } |
| return &protocol_sfd_; |
| } |
| |
| return nullptr; |
| } |
| |
| void Subprocess::WaitForExit() { |
| int exit_code = 1; |
| |
| D("waiting for pid %d", pid_); |
| while (pid_ != -1) { |
| int status; |
| if (pid_ == waitpid(pid_, &status, 0)) { |
| D("post waitpid (pid=%d) status=%04x", pid_, status); |
| if (WIFSIGNALED(status)) { |
| exit_code = 0x80 | WTERMSIG(status); |
| D("subprocess killed by signal %d", WTERMSIG(status)); |
| break; |
| } else if (!WIFEXITED(status)) { |
| D("subprocess didn't exit"); |
| break; |
| } else if (WEXITSTATUS(status) >= 0) { |
| exit_code = WEXITSTATUS(status); |
| D("subprocess exit code = %d", WEXITSTATUS(status)); |
| break; |
| } |
| } |
| } |
| |
| // If we have an open protocol FD send an exit packet. |
| if (protocol_sfd_ != -1) { |
| output_->data()[0] = exit_code; |
| if (output_->Write(ShellProtocol::kIdExit, 1)) { |
| D("wrote the exit code packet: %d", exit_code); |
| } else { |
| PLOG(ERROR) << "failed to write the exit code packet"; |
| } |
| protocol_sfd_.reset(-1); |
| } |
| } |
| |
| } // namespace |
| |
| // Create a pipe containing the error. |
| unique_fd ReportError(SubprocessProtocol protocol, const std::string& message) { |
| unique_fd read, write; |
| if (!Pipe(&read, &write)) { |
| PLOG(ERROR) << "failed to create pipe to report error"; |
| return unique_fd{}; |
| } |
| |
| std::string buf = android::base::StringPrintf("error: %s\n", message.c_str()); |
| if (protocol == SubprocessProtocol::kShell) { |
| ShellProtocol::Id id = ShellProtocol::kIdStderr; |
| uint32_t length = buf.length(); |
| WriteFdExactly(write.get(), &id, sizeof(id)); |
| WriteFdExactly(write.get(), &length, sizeof(length)); |
| } |
| |
| WriteFdExactly(write.get(), buf.data(), buf.length()); |
| |
| if (protocol == SubprocessProtocol::kShell) { |
| ShellProtocol::Id id = ShellProtocol::kIdExit; |
| uint32_t length = 1; |
| char exit_code = 126; |
| WriteFdExactly(write.get(), &id, sizeof(id)); |
| WriteFdExactly(write.get(), &length, sizeof(length)); |
| WriteFdExactly(write.get(), &exit_code, sizeof(exit_code)); |
| } |
| |
| return read; |
| } |
| |
| unique_fd StartSubprocess(std::string name, const char* terminal_type, SubprocessType type, |
| SubprocessProtocol protocol) { |
| // If we aren't using the shell protocol we must allocate a PTY to properly close the |
| // subprocess. PTYs automatically send SIGHUP to the slave-side process when the master side |
| // of the PTY closes, which we rely on. If we use a raw pipe, processes that don't read/write, |
| // e.g. screenrecord, will never notice the broken pipe and terminate. |
| // The shell protocol doesn't require a PTY because it's always monitoring the local socket FD |
| // with select() and will send SIGHUP manually to the child process. |
| bool make_pty_raw = false; |
| if (protocol == SubprocessProtocol::kNone && type == SubprocessType::kRaw) { |
| // Disable PTY input/output processing since the client is expecting raw data. |
| D("Can't create raw subprocess without shell protocol, using PTY in raw mode instead"); |
| type = SubprocessType::kPty; |
| make_pty_raw = true; |
| } |
| |
| unique_fd error_fd; |
| unique_fd fd = StartSubprocess(std::move(name), terminal_type, type, protocol, make_pty_raw, |
| protocol, &error_fd); |
| if (fd == -1) { |
| return error_fd; |
| } |
| return fd; |
| } |
| |
| unique_fd StartSubprocess(std::string name, const char* terminal_type, SubprocessType type, |
| SubprocessProtocol protocol, bool make_pty_raw, |
| SubprocessProtocol error_protocol, unique_fd* error_fd) { |
| D("starting %s subprocess (protocol=%s, TERM=%s): '%s'", |
| type == SubprocessType::kRaw ? "raw" : "PTY", |
| protocol == SubprocessProtocol::kNone ? "none" : "shell", terminal_type, name.c_str()); |
| |
| auto subprocess = std::make_unique<Subprocess>(std::move(name), terminal_type, type, protocol, |
| make_pty_raw); |
| if (!subprocess) { |
| LOG(ERROR) << "failed to allocate new subprocess"; |
| *error_fd = ReportError(error_protocol, "failed to allocate new subprocess"); |
| return {}; |
| } |
| |
| std::string error; |
| if (!subprocess->ForkAndExec(&error)) { |
| LOG(ERROR) << "failed to start subprocess: " << error; |
| *error_fd = ReportError(error_protocol, error); |
| return {}; |
| } |
| |
| unique_fd local_socket(subprocess->ReleaseLocalSocket()); |
| D("subprocess creation successful: local_socket_fd=%d, pid=%d", local_socket.get(), |
| subprocess->pid()); |
| |
| if (!Subprocess::StartThread(std::move(subprocess), &error)) { |
| LOG(ERROR) << "failed to start subprocess management thread: " << error; |
| *error_fd = ReportError(error_protocol, error); |
| return {}; |
| } |
| |
| return local_socket; |
| } |
| |
| unique_fd StartCommandInProcess(std::string name, Command command, SubprocessProtocol protocol) { |
| LOG(INFO) << "StartCommandInProcess(" << dump_hex(name.data(), name.size()) << ")"; |
| |
| constexpr auto terminal_type = ""; |
| constexpr auto type = SubprocessType::kRaw; |
| constexpr auto make_pty_raw = false; |
| |
| auto subprocess = std::make_unique<Subprocess>(std::move(name), terminal_type, type, protocol, |
| make_pty_raw); |
| if (!subprocess) { |
| LOG(ERROR) << "failed to allocate new subprocess"; |
| return ReportError(protocol, "failed to allocate new subprocess"); |
| } |
| |
| std::string error; |
| if (!subprocess->ExecInProcess(std::move(command), &error)) { |
| LOG(ERROR) << "failed to start subprocess: " << error; |
| return ReportError(protocol, error); |
| } |
| |
| unique_fd local_socket(subprocess->ReleaseLocalSocket()); |
| D("inprocess creation successful: local_socket_fd=%d, pid=%d", local_socket.get(), |
| subprocess->pid()); |
| |
| if (!Subprocess::StartThread(std::move(subprocess), &error)) { |
| LOG(ERROR) << "failed to start inprocess management thread: " << error; |
| return ReportError(protocol, error); |
| } |
| |
| return local_socket; |
| } |