/*
 *
 * Conky, a system monitor, based on torsmo
 *
 * Please see COPYING for details
 *
 * Copyright (C) 2010 Pavel Labath et al.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#include "config.h"

#include "c++wrap.hh"

#include <unistd.h>
#include <cstdio>

/* force use of  POSIX strerror_r instead of non-portable GNU specific */
#ifdef _GNU_SOURCE
#undef _GNU_SOURCE
#endif
#include <cstring>

#if __cplusplus <= 199711L
#define thread_local __thread
#endif

#if !defined(HAVE_PIPE2) || !defined(HAVE_O_CLOEXEC)
#include <fcntl.h>

namespace {
int pipe2_emulate(int pipefd[2], int flags) {
  if (pipe(pipefd) == -1) { return -1; }

  if ((flags & O_CLOEXEC) != 0) {
    // we emulate O_CLOEXEC if the system does not have it
    // not very thread-safe, but at least it works

    for (int i = 0; i < 2; ++i) {
      int r = fcntl(pipefd[i], F_GETFD);
      if (r == -1) { return -1; }

      if (fcntl(pipefd[i], F_SETFD, r | FD_CLOEXEC) == -1) { return -1; }
    }
  }

  return 0;
}

int (*const pipe2_ptr)(int[2], int) = &pipe2_emulate;
}  // namespace
#else
int (*const pipe2_ptr)(int[2], int) = &pipe2;
#endif

std::string strerror_r(int errnum) {
  static thread_local char buf[100];
  if (strerror_r(errnum, buf, sizeof buf) != 0) {
    snprintf(buf, sizeof buf, "Unknown error %i", errnum);
  }
  return buf;
}

std::pair<int, int> pipe2(int flags) {
  int fd[2];
  if (pipe2_ptr(fd, flags) == -1) { throw errno_error("pipe2"); }
  { return std::pair<int, int>(fd[0], fd[1]); }
}