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platform_system_core
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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
This commit is contained in:
Jorge Lucangeli Obes 2016-07-08 13:32:26 -04:00
parent c4dc4f3fc2
commit 344d01f99f
2 changed files with 112 additions and 100 deletions
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210
init/service.cpp
View File

@ -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, uid, context, and
// priority. Aborts on failure.
SetProcessAttributes();
// 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);
}
}
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");

2
init/service.h
View File

@ -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);