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#include <cerrno>
#include <charconv>
#include <cstring>
#include <iostream>
#include <unistd.h>
#include "args.hh"
#include "logger.hh"
#include "logger_file.hh"
#include "logger_syslog.hh"
#include "server.hh"
namespace {
struct Context {
std::shared_ptr<Logger> logger_;
bool verbose_{false};
bool daemon_{false};
std::string host_{"localhost"};
uint16_t port_{12000};
};
bool parse_args(int argc, char** argv, std::shared_ptr<Logger> logger,
Context& context, int& exit_code) {
auto args = Args::create();
auto opt_help = args->add_option('h', "help", "display this text and exit");
auto opt_version = args->add_option(
'V', "version", "display version and exit");
auto opt_verbose = args->add_option('v', "verbose", "be verbose");
auto opt_daemon = args->add_option(
'd', "daemon", "fork into the background as a daemon");
auto opt_logfile = args->add_option_with_arg(
'L', "log", "log to FILE instead of default ("
"syslog for daemon, stdout otherwise)", "FILE");
auto opt_host = args->add_option_with_arg(
'h', "host", "HOST to listen for requests on (default localhost)",
"HOST");
auto opt_port = args->add_option_with_arg(
'p', "port", "PORT to listen for requests on (default 12000)",
"PORT");
std::vector<std::string> extra;
if (!args->run(argc, argv, "buildhelper", std::cerr, extra)) {
std::cerr << "Try `buildhelper --help` for usage." << std::endl;
exit_code = 1;
return false;
}
if (opt_help->is_set()) {
std::cout << "Usage `buildhelper [OPTIONS]`.\n"
<< "Runs a buildhelper instance, implementing the Remote Execution API. Answers requests from bazel and others.\n"
<< "\n"
<< "Options:" << std::endl;
args->print_descriptions(std::cout, 80);
exit_code = 0;
return false;
}
if (opt_version->is_set()) {
std::cout << "buildhelper 0.1 written by Joel Klinghed <the_jk@spawned.biz>"
<< std::endl;
exit_code = 0;
return false;
}
context.verbose_ = opt_verbose->is_set();
context.daemon_ = opt_daemon->is_set();
if (opt_host->is_set()) {
context.host_ = opt_host->arg();
}
if (opt_port->is_set()) {
auto const& arg = opt_port->arg();
auto [ptr, err] =
std::from_chars(arg.data(), arg.data() + arg.size(), context.port_);
if (ptr != arg.data() + arg.size() || err != std::errc()) {
std::cerr << "Invalid port value: " << arg << std::endl;
exit_code = 1;
return false;
}
}
if (opt_logfile->is_set()) {
if (opt_logfile->arg() == "-") {
if (context.daemon_) {
std::cerr << "Cannot log to stdout AND fork into background."
<< std::endl;
exit_code = 1;
return false;
}
context.logger_ = logger;
} else {
context.logger_ = LoggerFile::create(
std::filesystem::path(opt_logfile->arg()),
logger.get());
}
} else {
if (context.daemon_) {
context.logger_ = LoggerSyslog::create("buildhelper");
} else {
context.logger_ = logger;
}
}
return true;
}
} // namespace
int main(int argc, char** argv) {
std::shared_ptr<Logger> logger = Logger::create_stdio();
Context context;
int exit_code = 0;
if (!parse_args(argc, argv, logger, context, exit_code)) {
return exit_code;
}
auto server = Server::create();
if (!server->setup(logger, context.host_, context.port_)) {
return 1;
}
if (context.daemon_) {
auto pid = fork();
if (pid == -1) {
logger->err("Unable to fork: %s", strerror(errno));
return 1;
}
if (pid == 0) {
// Child process
// Close stdin, stdout and stderr.
close(0);
close(1);
close(2);
// Chdir to root, avoid keeping started directory alive
chdir("/");
// Create new session
setsid();
} else {
// Parent process
if (context.verbose_)
logger->info("Forked as %ld", static_cast<long>(pid));
// Don't run atexit or anything like that, all is owned by child.
_exit(0);
}
}
logger.reset();
if (server->run(context.logger_))
return 0;
return 1;
}
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