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Commit 344d01f9 authored by Jorge Lucangeli Obes's avatar Jorge Lucangeli Obes
Browse files

Refactor Service::Start method. 

This CL extracts code from Service::Start into four helper functions,
bringing Service::Start down to 134 lines vs 212 lines originally. This
makes the method a lot easier to follow. There is no change in behaviour.

Also, make error messages consistent (start with lowercase) and
format Service::Start to fit in 100 cols.

Bug: 30035168

Change-Id: If979976fba4d339a336d030f802ca9f169fd012c
parent c4dc4f3f

init/service.cpp

+110 −100
Original line number Diff line number Diff line
@@ -52,6 +52,43 @@ using android::base::WriteStringToFile; 
#define CRITICAL_CRASH_THRESHOLD    4       // if we crash >4 times ...

#define CRITICAL_CRASH_WINDOW       (4*60)  // ... in 4 minutes, goto recovery



static std::string ComputeContextFromExecutable(std::string& service_name,

                                                const std::string& service_path) {

    std::string computed_context;



    char* raw_con = nullptr;

    char* raw_filecon = nullptr;



    if (getcon(&raw_con) == -1) {

        LOG(ERROR) << "could not get context while starting '" << service_name << "'";

        return "";

    }

    std::unique_ptr<char> mycon(raw_con);



    if (getfilecon(service_path.c_str(), &raw_filecon) == -1) {

        LOG(ERROR) << "could not get file context while starting '" << service_name << "'";

        return "";

    }

    std::unique_ptr<char> filecon(raw_filecon);



    char* new_con = nullptr;

    int rc = security_compute_create(mycon.get(), filecon.get(),

                                     string_to_security_class("process"), &new_con);

    if (rc == 0) {

        computed_context = new_con;

        free(new_con);

    }

    if (rc == 0 && computed_context == mycon.get()) {

        LOG(ERROR) << "service " << service_name << " does not have a SELinux domain defined";

        return "";

    }

    if (rc < 0) {

        LOG(ERROR) << "could not get context while starting '" << service_name << "'";

        return "";

    }

    return computed_context;

}



static void SetUpPidNamespace(const std::string& service_name) {

    constexpr unsigned int kSafeFlags = MS_NODEV | MS_NOEXEC | MS_NOSUID;
@@ -92,6 +129,19 @@ static void SetUpPidNamespace(const std::string& service_name) { 
    }

}



static void ExpandArgs(const std::vector<std::string>& args, std::vector<char*>* strs) {

    std::vector<std::string> expanded_args;

    expanded_args.resize(args.size());

    strs->push_back(const_cast<char*>(args[0].c_str()));

    for (std::size_t i = 1; i < args.size(); ++i) {

        if (!expand_props(args[i], &expanded_args[i])) {

            LOG(FATAL) << args[0] << ": cannot expand '" << args[i] << "'";

        }

        strs->push_back(const_cast<char*>(expanded_args[i].c_str()));

    }

    strs->push_back(nullptr);

}



SocketInfo::SocketInfo() : uid(0), gid(0), perm(0) {

}
@@ -154,6 +204,50 @@ void Service::KillProcessGroup(int signal) { 
    killProcessGroup(uid_, pid_, signal);

}



void Service::CreateSockets(const std::string& context) {

    for (const auto& si : sockets_) {

        int socket_type = ((si.type == "stream" ? SOCK_STREAM :

                            (si.type == "dgram" ? SOCK_DGRAM :

                             SOCK_SEQPACKET)));

        const char* socketcon = !si.socketcon.empty() ? si.socketcon.c_str() : context.c_str();



        int s = create_socket(si.name.c_str(), socket_type, si.perm, si.uid, si.gid, socketcon);

        if (s >= 0) {

            PublishSocket(si.name, s);

        }

    }

}



void Service::SetProcessAttributes() {

    setpgid(0, getpid());



    if (gid_) {

        if (setgid(gid_) != 0) {

            PLOG(FATAL) << "setgid failed";

        }

    }

    if (!supp_gids_.empty()) {

        if (setgroups(supp_gids_.size(), &supp_gids_[0]) != 0) {

            PLOG(FATAL) << "setgroups failed";

        }

    }

    if (uid_) {

        if (setuid(uid_) != 0) {

            PLOG(FATAL) << "setuid failed";

        }

    }

    if (!seclabel_.empty()) {

        if (setexeccon(seclabel_.c_str()) < 0) {

            PLOG(FATAL) << "cannot setexeccon('" << seclabel_ << "')";

        }

    }

    if (priority_ != 0) {

        if (setpriority(PRIO_PROCESS, 0, priority_) != 0) {

            PLOG(FATAL) << "setpriority failed";

        }

    }

}



bool Service::Reap() {

    if (!(flags_ & SVC_ONESHOT) || (flags_ & SVC_RESTART)) {

        KillProcessGroup(SIGKILL);
@@ -441,50 +535,18 @@ bool Service::Start() { 
    if (!seclabel_.empty()) {

        scon = seclabel_;

    } else {

        char* mycon = nullptr;

        char* fcon = nullptr;



        LOG(INFO) << "computing context for service '" << args_[0] << "'";

        int rc = getcon(&mycon);

        if (rc < 0) {

            LOG(ERROR) << "could not get context while starting '" << name_ << "'";

            return false;

        }



        rc = getfilecon(args_[0].c_str(), &fcon);

        if (rc < 0) {

            LOG(ERROR) << "could not get file context while starting '" << name_ << "'";

            free(mycon);

            return false;

        }



        char* ret_scon = nullptr;

        rc = security_compute_create(mycon, fcon, string_to_security_class("process"),

                                     &ret_scon);

        if (rc == 0) {

            scon = ret_scon;

            free(ret_scon);

        }

        if (rc == 0 && scon == mycon) {

            LOG(ERROR) << "Service " << name_ << " does not have a SELinux domain defined.";

            free(mycon);

            free(fcon);

            return false;

        }

        free(mycon);

        free(fcon);

        if (rc < 0) {

            LOG(ERROR) << "could not get context while starting '" << name_ << "'";

        LOG(INFO) << "computing context for service '" << name_ << "'";

        scon = ComputeContextFromExecutable(name_, args_[0]);

        if (scon == "") {

            return false;

        }

    }



    LOG(VERBOSE) << "Starting service '" << name_ << "'...";

    LOG(VERBOSE) << "starting service '" << name_ << "'...";



    pid_t pid = -1;

    if (namespace_flags_) {

        pid = clone(nullptr, nullptr, namespace_flags_ | SIGCHLD,

                    nullptr);

        pid = clone(nullptr, nullptr, namespace_flags_ | SIGCHLD, nullptr);

    } else {

        pid = fork();

    }
@@ -502,19 +564,7 @@ bool Service::Start() { 
            add_environment(ei.name.c_str(), ei.value.c_str());

        }



        for (const auto& si : sockets_) {

            int socket_type = ((si.type == "stream" ? SOCK_STREAM :

                                (si.type == "dgram" ? SOCK_DGRAM :

                                 SOCK_SEQPACKET)));

            const char* socketcon =

                !si.socketcon.empty() ? si.socketcon.c_str() : scon.c_str();



            int s = create_socket(si.name.c_str(), socket_type, si.perm,

                                  si.uid, si.gid, socketcon);

            if (s >= 0) {

                PublishSocket(si.name, s);

            }

        }

        CreateSockets(scon);



        std::string pid_str = StringPrintf("%d", getpid());

        for (const auto& file : writepid_files_) {
@@ -525,7 +575,7 @@ bool Service::Start() { 


        if (ioprio_class_ != IoSchedClass_NONE) {

            if (android_set_ioprio(getpid(), ioprio_class_, ioprio_pri_)) {

                PLOG(ERROR) << "Failed to set pid " << getpid()

                PLOG(ERROR) << "failed to set pid " << getpid()

                            << " ioprio=" << ioprio_class_ << "," << ioprio_pri_;

            }

        }
@@ -537,53 +587,12 @@ bool Service::Start() { 
            ZapStdio();

        }



        setpgid(0, getpid());



        // As requested, set our gid, supplemental gids, and uid.

        if (gid_) {

            if (setgid(gid_) != 0) {

                PLOG(ERROR) << "setgid failed";

                _exit(127);

            }

        }

        if (!supp_gids_.empty()) {

            if (setgroups(supp_gids_.size(), &supp_gids_[0]) != 0) {

                PLOG(ERROR) << "setgroups failed";

                _exit(127);

            }

        }

        if (uid_) {

            if (setuid(uid_) != 0) {

                PLOG(ERROR) << "setuid failed";

                _exit(127);

            }

        }

        if (!seclabel_.empty()) {

            if (setexeccon(seclabel_.c_str()) < 0) {

                PLOG(ERROR) << "cannot setexeccon('" << seclabel_ << "')";

                _exit(127);

            }

        }

        if (priority_ != 0) {

            if (setpriority(PRIO_PROCESS, 0, priority_) != 0) {

                PLOG(ERROR) << "setpriority failed";

                _exit(127);

            }

        }

        // As requested, set our gid, supplemental gids, uid, context, and

        // priority. Aborts on failure.

        SetProcessAttributes();



        std::vector<std::string> expanded_args;

        std::vector<char*> strs;

        expanded_args.resize(args_.size());

        strs.push_back(const_cast<char*>(args_[0].c_str()));

        for (std::size_t i = 1; i < args_.size(); ++i) {

            if (!expand_props(args_[i], &expanded_args[i])) {

                LOG(ERROR) << args_[0] << ": cannot expand '" << args_[i] << "'";

                _exit(127);

            }

            strs.push_back(const_cast<char*>(expanded_args[i].c_str()));

        }

        strs.push_back(nullptr);



        ExpandArgs(args_, &strs);

        if (execve(strs[0], (char**) &strs[0], (char**) ENV) < 0) {

            PLOG(ERROR) << "cannot execve('" << strs[0] << "')";

        }
@@ -603,13 +612,14 @@ bool Service::Start() { 


    errno = -createProcessGroup(uid_, pid_);

    if (errno != 0) {

        PLOG(ERROR) << "createProcessGroup(" << uid_ << ", " << pid_ << ") failed for service '" << name_ << "'";

        PLOG(ERROR) << "createProcessGroup(" << uid_ << ", " << pid_ << ") failed for service '"

                    << name_ << "'";

    }



    if ((flags_ & SVC_EXEC) != 0) {

        LOG(INFO) << android::base::StringPrintf("SVC_EXEC pid %d (uid %d gid %d+%zu context %s) started; waiting...",

                                                 pid_, uid_, gid_, supp_gids_.size(),

                                                 !seclabel_.empty() ? seclabel_.c_str() : "default");

        LOG(INFO) << android::base::StringPrintf(

            "SVC_EXEC pid %d (uid %d gid %d+%zu context %s) started; waiting...", pid_, uid_, gid_,

            supp_gids_.size(), !seclabel_.empty() ? seclabel_.c_str() : "default");

    }



    NotifyStateChange("running");

init/service.h

+2 −0
Original line number Diff line number Diff line
@@ -113,6 +113,8 @@ private: 
    void OpenConsole() const;

    void PublishSocket(const std::string& name, int fd) const;

    void KillProcessGroup(int signal);

    void CreateSockets(const std::string& scon);

    void SetProcessAttributes();



    bool ParseClass(const std::vector<std::string>& args, std::string* err);

    bool ParseConsole(const std::vector<std::string>& args, std::string* err);