LSBUtils.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "LSBUtils.h"

#include <unistd.h>
#include "base/process_util.h"
#include "mozilla/FileUtils.h"
#include "mozilla/Result.h"
#include "mozilla/ResultVariant.h"
#include "mozilla/ipc/LaunchError.h"

namespace mozilla::widget::lsb {

static const char* gLsbReleasePath = "/usr/bin/lsb_release";

bool GetLSBRelease(nsACString& aDistributor, nsACString& aDescription,
                   nsACString& aRelease, nsACString& aCodename) {
  if (access(gLsbReleasePath, R_OK) != 0) return false;

  int pipefd[2];
  if (pipe(pipefd) == -1) {
    NS_WARNING("pipe() failed!");
    return false;
  }

  std::vector<std::string> argv = {gLsbReleasePath, "-idrc"};

  base::LaunchOptions options;
  options.fds_to_remap.push_back({pipefd[1], STDOUT_FILENO});
  options.wait = true;

  base::ProcessHandle process;
  Result<Ok, ipc::LaunchError> err =
      base::LaunchApp(argv, std::move(options), &process);
  close(pipefd[1]);
  if (err.isErr()) {
    NS_WARNING("Failed to spawn lsb_release!");
    close(pipefd[0]);
    return false;
  }

  ScopedCloseFile stream(fdopen(pipefd[0], "r"));
  if (!stream) {
    NS_WARNING("Could not wrap fd!");
    close(pipefd[0]);
    return false;
  }

  char dist[256], desc[256], release[256], codename[256];
  if (fscanf(stream,
             "Distributor ID:\t%255[^\n]\n"
             "Description:\t%255[^\n]\n"
             "Release:\t%255[^\n]\n"
             "Codename:\t%255[^\n]\n",
             dist, desc, release, codename) != 4) {
    NS_WARNING("Failed to parse lsb_release!");
    return false;
  }

  aDistributor.Assign(dist);
  aDescription.Assign(desc);
  aRelease.Assign(release);
  aCodename.Assign(codename);
  return true;
}

}  // namespace mozilla::widget::lsb