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Commit 21541531 authored by David Pursell's avatar David Pursell Committed by Gerrit Code Review
Browse files

Merge changes from topic 'adb_shell_prework'

* changes:
  adb: create shell protocol class.
  adb: refactor subprocess code.
  adb: move shell service to a separate file.
parents 30c13c49 73096f2e
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+11 −1
Original line number Diff line number Diff line
@@ -131,6 +131,8 @@ LOCAL_CFLAGS := -DADB_HOST=0 $(LIBADB_CFLAGS)
LOCAL_SRC_FILES := \
    $(LIBADB_TEST_SRCS) \
    $(LIBADB_TEST_linux_SRCS) \
    shell_service_protocol.cpp \
    shell_service_protocol_test.cpp \

LOCAL_SANITIZE := $(adb_target_sanitize)
LOCAL_STATIC_LIBRARIES := libadbd
@@ -145,7 +147,12 @@ LOCAL_MODULE := adb_test
LOCAL_CFLAGS := -DADB_HOST=1 $(LIBADB_CFLAGS)
LOCAL_CFLAGS_windows := $(LIBADB_windows_CFLAGS)
LOCAL_CFLAGS_linux := $(LIBADB_linux_CFLAGS)
LOCAL_SRC_FILES := $(LIBADB_TEST_SRCS) services.cpp
LOCAL_SRC_FILES := \
    $(LIBADB_TEST_SRCS) \
    services.cpp \
    shell_service_protocol.cpp \
    shell_service_protocol_test.cpp \

LOCAL_SRC_FILES_linux := $(LIBADB_TEST_linux_SRCS)
LOCAL_SRC_FILES_darwin := $(LIBADB_TEST_darwin_SRCS)
LOCAL_SANITIZE := $(adb_host_sanitize)
@@ -201,6 +208,7 @@ LOCAL_SRC_FILES := \
    adb_client.cpp \
    services.cpp \
    file_sync_client.cpp \
    shell_service_protocol.cpp \

LOCAL_CFLAGS += \
    $(ADB_COMMON_CFLAGS) \
@@ -248,6 +256,8 @@ LOCAL_SRC_FILES := \
    framebuffer_service.cpp \
    remount_service.cpp \
    set_verity_enable_state_service.cpp \
    shell_service.cpp \
    shell_service_protocol.cpp \

LOCAL_CFLAGS := \
    $(ADB_COMMON_CFLAGS) \
+2 −1
Original line number Diff line number Diff line
@@ -176,7 +176,8 @@ static void setup_trace_mask() {
        {"transport", TRACE_TRANSPORT},
        {"jdwp", TRACE_JDWP},
        {"services", TRACE_SERVICES},
        {"auth", TRACE_AUTH}};
        {"auth", TRACE_AUTH},
        {"shell", TRACE_SHELL}};

    std::vector<std::string> elements = android::base::Split(trace_setting, " ");
    for (const auto& elem : elements) {
+1 −0
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ enum AdbTrace {
    TRACE_SERVICES,
    TRACE_AUTH,
    TRACE_FDEVENT,
    TRACE_SHELL
};

extern int adb_trace_mask;
+8 −222
Original line number Diff line number Diff line
@@ -24,11 +24,6 @@
#include <stdlib.h>
#include <string.h>

#if !ADB_HOST
#include <pty.h>
#include <termios.h>
#endif

#ifndef _WIN32
#include <netdb.h>
#include <netinet/in.h>
@@ -51,6 +46,7 @@
#include "adb_utils.h"
#include "file_sync_service.h"
#include "remount_service.h"
#include "shell_service.h"
#include "transport.h"

struct stinfo {
@@ -59,11 +55,6 @@ struct stinfo {
    void *cookie;
};

enum class SubprocessType {
    kPty,
    kRaw,
};

void *service_bootstrap_func(void *x)
{
    stinfo* sti = reinterpret_cast<stinfo*>(x);
@@ -234,211 +225,6 @@ static int create_service_thread(void (*func)(int, void *), void *cookie)
    return s[0];
}

#if !ADB_HOST

static void init_subproc_child()
{
    setsid();

    // Set OOM score adjustment to prevent killing
    int fd = adb_open("/proc/self/oom_score_adj", O_WRONLY | O_CLOEXEC);
    if (fd >= 0) {
        adb_write(fd, "0", 1);
        adb_close(fd);
    } else {
       D("adb: unable to update oom_score_adj");
    }
}

#if !ADB_HOST
static int create_subproc_pty(const char* cmd, const char* arg0,
                              const char* arg1, pid_t* pid) {
    D("create_subproc_pty(cmd=%s, arg0=%s, arg1=%s)", cmd, arg0, arg1);
    char pts_name[PATH_MAX];
    int ptm;
    *pid = forkpty(&ptm, pts_name, nullptr, nullptr);
    if (*pid == -1) {
        printf("- fork failed: %s -\n", strerror(errno));
        unix_close(ptm);
        return -1;
    }

    if (*pid == 0) {
        init_subproc_child();

        int pts = unix_open(pts_name, O_RDWR | O_CLOEXEC);
        if (pts == -1) {
            fprintf(stderr, "child failed to open pseudo-term slave %s: %s\n",
                    pts_name, strerror(errno));
            unix_close(ptm);
            exit(-1);
        }

        // arg0 is "-c" in batch mode and "-" in interactive mode.
        if (strcmp(arg0, "-c") == 0) {
            termios tattr;
            if (tcgetattr(pts, &tattr) == -1) {
                fprintf(stderr, "tcgetattr failed: %s\n", strerror(errno));
                unix_close(pts);
                unix_close(ptm);
                exit(-1);
            }

            cfmakeraw(&tattr);
            if (tcsetattr(pts, TCSADRAIN, &tattr) == -1) {
                fprintf(stderr, "tcsetattr failed: %s\n", strerror(errno));
                unix_close(pts);
                unix_close(ptm);
                exit(-1);
            }
        }

        dup2(pts, STDIN_FILENO);
        dup2(pts, STDOUT_FILENO);
        dup2(pts, STDERR_FILENO);

        unix_close(pts);
        unix_close(ptm);

        execl(cmd, cmd, arg0, arg1, nullptr);
        fprintf(stderr, "- exec '%s' failed: %s (%d) -\n",
                cmd, strerror(errno), errno);
        exit(-1);
    } else {
        return ptm;
    }
}
#endif // !ADB_HOST

static int create_subproc_raw(const char *cmd, const char *arg0, const char *arg1, pid_t *pid)
{
    D("create_subproc_raw(cmd=%s, arg0=%s, arg1=%s)", cmd, arg0, arg1);
#if defined(_WIN32)
    fprintf(stderr, "error: create_subproc_raw not implemented on Win32 (%s %s %s)\n", cmd, arg0, arg1);
    return -1;
#else

    // 0 is parent socket, 1 is child socket
    int sv[2];
    if (adb_socketpair(sv) < 0) {
        printf("[ cannot create socket pair - %s ]\n", strerror(errno));
        return -1;
    }
    D("socketpair: (%d,%d)", sv[0], sv[1]);

    *pid = fork();
    if (*pid < 0) {
        printf("- fork failed: %s -\n", strerror(errno));
        adb_close(sv[0]);
        adb_close(sv[1]);
        return -1;
    }

    if (*pid == 0) {
        adb_close(sv[0]);
        init_subproc_child();

        dup2(sv[1], STDIN_FILENO);
        dup2(sv[1], STDOUT_FILENO);
        dup2(sv[1], STDERR_FILENO);

        adb_close(sv[1]);

        execl(cmd, cmd, arg0, arg1, NULL);
        fprintf(stderr, "- exec '%s' failed: %s (%d) -\n",
                cmd, strerror(errno), errno);
        exit(-1);
    } else {
        adb_close(sv[1]);
        return sv[0];
    }
#endif /* !defined(_WIN32) */
}
#endif  /* !ABD_HOST */

#if ADB_HOST
#define SHELL_COMMAND "/bin/sh"
#else
#define SHELL_COMMAND "/system/bin/sh"
#endif

#if !ADB_HOST
static void subproc_waiter_service(int fd, void *cookie)
{
    pid_t pid = (pid_t) (uintptr_t) cookie;

    D("entered. fd=%d of pid=%d", fd, pid);
    while (true) {
        int status;
        pid_t p = waitpid(pid, &status, 0);
        if (p == pid) {
            D("fd=%d, post waitpid(pid=%d) status=%04x", fd, p, status);
            if (WIFSIGNALED(status)) {
                D("*** Killed by signal %d", WTERMSIG(status));
                break;
            } else if (!WIFEXITED(status)) {
                D("*** Didn't exit!!. status %d", status);
                break;
            } else if (WEXITSTATUS(status) >= 0) {
                D("*** Exit code %d", WEXITSTATUS(status));
                break;
            }
         }
    }
    D("shell exited fd=%d of pid=%d err=%d", fd, pid, errno);
    if (SHELL_EXIT_NOTIFY_FD >=0) {
      int res;
      res = WriteFdExactly(SHELL_EXIT_NOTIFY_FD, &fd, sizeof(fd)) ? 0 : -1;
      D("notified shell exit via fd=%d for pid=%d res=%d errno=%d",
        SHELL_EXIT_NOTIFY_FD, pid, res, errno);
    }
}

// Starts a subprocess and spawns a thread to wait for the subprocess to finish
// and trigger the necessary cleanup.
//
// |name| is the command to execute in the subprocess; empty string will start
//     an interactive session.
// |type| selects between a PTY or raw subprocess.
//
// Returns an open file descriptor tied to the subprocess stdin/stdout/stderr.
static int create_subproc_thread(const char *name, SubprocessType type) {
    const char *arg0, *arg1;
    if (*name == '\0') {
        arg0 = "-";
        arg1 = nullptr;
    } else {
        arg0 = "-c";
        arg1 = name;
    }

    pid_t pid = -1;
    int ret_fd;
    if (type == SubprocessType::kPty) {
        ret_fd = create_subproc_pty(SHELL_COMMAND, arg0, arg1, &pid);
    } else {
        ret_fd = create_subproc_raw(SHELL_COMMAND, arg0, arg1, &pid);
    }
    D("create_subproc ret_fd=%d pid=%d", ret_fd, pid);

    stinfo* sti = reinterpret_cast<stinfo*>(malloc(sizeof(stinfo)));
    if(sti == 0) fatal("cannot allocate stinfo");
    sti->func = subproc_waiter_service;
    sti->cookie = (void*) (uintptr_t) pid;
    sti->fd = ret_fd;

    if (!adb_thread_create(service_bootstrap_func, sti)) {
        free(sti);
        adb_close(ret_fd);
        fprintf(stderr, "cannot create service thread\n");
        return -1;
    }

    D("service thread started, fd=%d pid=%d", ret_fd, pid);
    return ret_fd;
}
#endif

int service_to_fd(const char* name) {
    int ret = -1;

@@ -483,13 +269,13 @@ int service_to_fd(const char* name) {
        const char* args = name + 6;
        if (*args) {
            // Non-interactive session uses a raw subprocess.
            ret = create_subproc_thread(args, SubprocessType::kRaw);
            ret = StartSubprocess(args, SubprocessType::kRaw);
        } else {
            // Interactive session uses a PTY subprocess.
            ret = create_subproc_thread(args, SubprocessType::kPty);
            ret = StartSubprocess(args, SubprocessType::kPty);
        }
    } else if(!strncmp(name, "exec:", 5)) {
        ret = create_subproc_thread(name + 5, SubprocessType::kRaw);
        ret = StartSubprocess(name + 5, SubprocessType::kRaw);
    } else if(!strncmp(name, "sync:", 5)) {
        ret = create_service_thread(file_sync_service, NULL);
    } else if(!strncmp(name, "remount:", 8)) {
@@ -503,11 +289,11 @@ int service_to_fd(const char* name) {
    } else if(!strncmp(name, "unroot:", 7)) {
        ret = create_service_thread(restart_unroot_service, NULL);
    } else if(!strncmp(name, "backup:", 7)) {
        ret = create_subproc_thread(android::base::StringPrintf("/system/bin/bu backup %s",
        ret = StartSubprocess(android::base::StringPrintf("/system/bin/bu backup %s",
                                                          (name + 7)).c_str(),
                              SubprocessType::kRaw);
    } else if(!strncmp(name, "restore:", 8)) {
        ret = create_subproc_thread("/system/bin/bu restore", SubprocessType::kRaw);
        ret = StartSubprocess("/system/bin/bu restore", SubprocessType::kRaw);
    } else if(!strncmp(name, "tcpip:", 6)) {
        int port;
        if (sscanf(name + 6, "%d", &port) != 1) {

adb/shell_service.cpp

0 → 100644
+329 −0
Original line number Diff line number Diff line
/*
 * 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.
 */

#define TRACE_TAG TRACE_SHELL

#include "shell_service.h"

#if !ADB_HOST

#include <errno.h>
#include <pty.h>
#include <termios.h>

#include <base/logging.h>
#include <base/stringprintf.h>
#include <paths.h>

#include "adb.h"
#include "adb_io.h"
#include "adb_trace.h"
#include "sysdeps.h"

namespace {

void init_subproc_child()
{
    setsid();

    // Set OOM score adjustment to prevent killing
    int fd = adb_open("/proc/self/oom_score_adj", O_WRONLY | O_CLOEXEC);
    if (fd >= 0) {
        adb_write(fd, "0", 1);
        adb_close(fd);
    } else {
       D("adb: unable to update oom_score_adj");
    }
}

// Reads from |fd| until close or failure.
std::string ReadAll(int 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;
}

// Helper to automatically close an FD when it goes out of scope.
class ScopedFd {
  public:
    ScopedFd() {}
    ~ScopedFd() { Reset(); }

    void Reset(int fd=-1) {
        if (fd != fd_) {
            if (valid()) {
                adb_close(fd_);
            }
            fd_ = fd;
        }
    }

    int Release() {
        int temp = fd_;
        fd_ = -1;
        return temp;
    }

    bool valid() const { return fd_ >= 0; }

    int fd() const { return fd_; }

  private:
    int fd_ = -1;

    DISALLOW_COPY_AND_ASSIGN(ScopedFd);
};

// Creates a socketpair and saves the endpoints to |fd1| and |fd2|.
bool CreateSocketpair(ScopedFd* fd1, ScopedFd* 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(const std::string& command, SubprocessType type);
    ~Subprocess();

    const std::string& command() const { return command_; }
    bool is_interactive() const { return command_.empty(); }

    int local_socket_fd() const { return local_socket_sfd_.fd(); }

    pid_t pid() const { return pid_; }

    // Sets up FDs, forks a subprocess, starts the subprocess manager thread,
    // and exec's the child. Returns false on failure.
    bool ForkAndExec();

  private:
    // Opens the file at |pts_name|.
    int OpenPtyChildFd(const char* pts_name, ScopedFd* error_sfd);

    static void* ThreadHandler(void* userdata);
    void WaitForExit();

    const std::string command_;
    SubprocessType type_;

    pid_t pid_ = -1;
    ScopedFd local_socket_sfd_;

    DISALLOW_COPY_AND_ASSIGN(Subprocess);
};

Subprocess::Subprocess(const std::string& command, SubprocessType type)
        : command_(command), type_(type) {
}

Subprocess::~Subprocess() {
}

bool Subprocess::ForkAndExec() {
    ScopedFd parent_sfd, child_sfd, parent_error_sfd, child_error_sfd;
    char pts_name[PATH_MAX];

    // Create a socketpair for the fork() child to report any errors back to
    // the parent. Since we use threads, logging directly from the child could
    // create a race condition.
    if (!CreateSocketpair(&parent_error_sfd, &child_error_sfd)) {
        LOG(ERROR) << "failed to create pipe for subprocess error reporting";
    }

    if (type_ == SubprocessType::kPty) {
        int fd;
        pid_ = forkpty(&fd, pts_name, nullptr, nullptr);
        parent_sfd.Reset(fd);
    } else {
        if (!CreateSocketpair(&parent_sfd, &child_sfd)) {
            return false;
        }
        pid_ = fork();
    }

    if (pid_ == -1) {
        PLOG(ERROR) << "fork failed";
        return false;
    }

    if (pid_ == 0) {
        // Subprocess child.
        init_subproc_child();

        if (type_ == SubprocessType::kPty) {
            child_sfd.Reset(OpenPtyChildFd(pts_name, &child_error_sfd));
        }

        dup2(child_sfd.fd(), STDIN_FILENO);
        dup2(child_sfd.fd(), STDOUT_FILENO);
        dup2(child_sfd.fd(), STDERR_FILENO);

        // exec doesn't trigger destructors, close the FDs manually.
        parent_sfd.Reset();
        child_sfd.Reset();
        parent_error_sfd.Reset();
        close_on_exec(child_error_sfd.fd());

        if (is_interactive()) {
            execl(_PATH_BSHELL, _PATH_BSHELL, "-", nullptr);
        } else {
            execl(_PATH_BSHELL, _PATH_BSHELL, "-c", command_.c_str(), nullptr);
        }
        WriteFdExactly(child_error_sfd.fd(), "exec '" _PATH_BSHELL "' failed");
        child_error_sfd.Reset();
        exit(-1);
    }

    // Subprocess parent.
    D("subprocess parent: subprocess FD = %d", parent_sfd.fd());

    // Wait to make sure the subprocess exec'd without error.
    child_error_sfd.Reset();
    std::string error_message = ReadAll(parent_error_sfd.fd());
    if (!error_message.empty()) {
        LOG(ERROR) << error_message;
        return false;
    }

    local_socket_sfd_.Reset(parent_sfd.Release());

    if (!adb_thread_create(ThreadHandler, this)) {
        PLOG(ERROR) << "failed to create subprocess thread";
        return false;
    }

    return true;
}

int Subprocess::OpenPtyChildFd(const char* pts_name, ScopedFd* 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->fd(), message);
        }
        exit(-1);
    }

    if (!is_interactive()) {
        termios tattr;
        if (tcgetattr(child_fd, &tattr) == -1) {
            WriteFdExactly(error_sfd->fd(), "tcgetattr failed");
            exit(-1);
        }

        cfmakeraw(&tattr);
        if (tcsetattr(child_fd, TCSADRAIN, &tattr) == -1) {
            WriteFdExactly(error_sfd->fd(), "tcsetattr failed");
            exit(-1);
        }
    }

    return child_fd;
}

void* Subprocess::ThreadHandler(void* userdata) {
    Subprocess* subprocess = reinterpret_cast<Subprocess*>(userdata);

    adb_thread_setname(android::base::StringPrintf(
            "shell srvc %d", subprocess->local_socket_fd()));

    subprocess->WaitForExit();

    D("deleting Subprocess");
    delete subprocess;

    return nullptr;
}

void Subprocess::WaitForExit() {
    D("waiting for pid %d", pid_);
    while (true) {
        int status;
        if (pid_ == waitpid(pid_, &status, 0)) {
            D("post waitpid (pid=%d) status=%04x", pid_, status);
            if (WIFSIGNALED(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) {
                D("subprocess exit code = %d", WEXITSTATUS(status));
                break;
            }
        }
    }

    // Pass the local socket FD to the shell cleanup fdevent.
    if (SHELL_EXIT_NOTIFY_FD >= 0) {
        int fd = local_socket_sfd_.fd();
        if (WriteFdExactly(SHELL_EXIT_NOTIFY_FD, &fd, sizeof(fd))) {
            D("passed fd %d to SHELL_EXIT_NOTIFY_FD (%d) for pid %d",
              fd, SHELL_EXIT_NOTIFY_FD, pid_);
            // The shell exit fdevent now owns the FD and will close it once
            // the last bit of data flushes through.
            local_socket_sfd_.Release();
        } else {
            PLOG(ERROR) << "failed to write fd " << fd
                        << " to SHELL_EXIT_NOTIFY_FD (" << SHELL_EXIT_NOTIFY_FD
                        << ") for pid " << pid_;
        }
    }
}

}  // namespace

int StartSubprocess(const char *name, SubprocessType type) {
    D("starting %s subprocess: '%s'",
      type == SubprocessType::kRaw ? "raw" : "PTY", name);

    Subprocess* subprocess = new Subprocess(name, type);
    if (!subprocess) {
        LOG(ERROR) << "failed to allocate new subprocess";
        return -1;
    }

    if (!subprocess->ForkAndExec()) {
        LOG(ERROR) << "failed to start subprocess";
        delete subprocess;
        return -1;
    }

    D("subprocess creation successful: local_socket_fd=%d, pid=%d",
      subprocess->local_socket_fd(), subprocess->pid());
    return subprocess->local_socket_fd();
}

#endif  // !ADB_HOST
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