Initial commitHEADmain

1 files changed, 153 insertions, 0 deletions

diff --git a/src/main.cc b/src/main.cc
new file mode 100644
index 0000000..980adba
--- /dev/null
+++ b/src/main.cc
@@ -0,0 +1,153 @@
+#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;
+}