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#include "common.hh"
#include "daemon.hh"
#include "io.hh"
#include "logger.hh"
#include "logger_base.hh"
#include "unique_pipe.hh"
#include <errno.h>
#include <string.h>
#include <unistd.h>
namespace {
enum class Type {
EXIT_GOOD,
EXIT_BAD,
LOG_ERR,
LOG_WARN,
LOG_INFO,
LOG_DBG,
};
struct MsgHeader {
Type type_;
size_t len_;
MsgHeader() = default;
MsgHeader(Type type, size_t len)
: type_(type), len_(len) {}
};
class DaemonWriter : public LoggerBase {
public:
explicit DaemonWriter(unique_fd fd)
: fd_(std::move(fd)) {}
void exit(bool success) {
MsgHeader header(success ? Type::EXIT_GOOD : Type::EXIT_BAD, 0);
if (!io::write_all(fd_.get(), &header, sizeof(header))) {
abort();
}
}
protected:
void msg(Level level, std::string_view str) override {
Type type;
switch (level) {
case Level::ERR:
type = Type::LOG_ERR;
break;
case Level::WARN:
type = Type::LOG_WARN;
break;
case Level::INFO:
type = Type::LOG_INFO;
break;
case Level::DBG:
type = Type::LOG_DBG;
break;
}
MsgHeader header(type, str.size());
if (!io::write_all(fd_.get(), &header, sizeof(header)) ||
!io::write_all(fd_.get(), str.data(), str.size())) {
abort();
}
}
private:
unique_fd fd_;
};
class DaemonReader {
public:
explicit DaemonReader(unique_fd fd)
: fd_(std::move(fd)) {}
bool wait(Logger* logger) {
MsgHeader header;
std::string msg;
while (true) {
if (!io::read_all(fd_.get(), &header, sizeof(header))) {
logger->err("Error reading pipe: %s", strerror(errno));
return false;
}
msg.resize(header.len_);
if (!io::read_all(fd_.get(), msg.data(), header.len_)) {
logger->err("Error reading pipe: %s", strerror(errno));
return false;
}
switch (header.type_) {
case Type::EXIT_GOOD:
return true;
case Type::EXIT_BAD:
return false;
case Type::LOG_ERR:
logger->err("%.*s", static_cast<int>(msg.size()), msg.data());
break;
case Type::LOG_WARN:
logger->warn("%.*s", static_cast<int>(msg.size()), msg.data());
break;
case Type::LOG_INFO:
logger->info("%.*s", static_cast<int>(msg.size()), msg.data());
break;
case Type::LOG_DBG:
logger->dbg("%.*s", static_cast<int>(msg.size()), msg.data());
break;
}
}
}
private:
unique_fd fd_;
};
} // namespace
bool Daemon::run_in_foreground(Logger* logger,
std::unique_ptr<Daemon> daemon) {
return daemon->setup(logger) && daemon->run();
}
bool Daemon::fork_in_background(Logger* logger,
std::unique_ptr<Daemon> daemon) {
unique_pipe pipe;
if (!pipe) {
logger->err("Unable to create pipe(): %s", strerror(errno));
return false;
}
auto pid = fork();
if (pid == -1) {
logger->err("Failed to fork(): %s", strerror(errno));
return false;
}
if (pid == 0) {
// Daemon process
setpgrp();
close(STDIN_FILENO);
close(STDOUT_FILENO);
close(STDERR_FILENO);
{
DaemonWriter writer(pipe.release_writer());
pipe.reset();
if (!daemon->setup(&writer)) {
writer.exit(false);
exit(EXIT_FAILURE);
}
writer.exit(true);
}
chdir("/");
exit(daemon->run() ? EXIT_SUCCESS : EXIT_FAILURE);
} else {
// Calling process
DaemonReader reader(pipe.release_reader());
pipe.reset();
return reader.wait(logger);
}
}
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