/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
│                                                                              │
│ Permission to use, copy, modify, and/or distribute this software for         │
│ any purpose with or without fee is hereby granted, provided that the         │
│ above copyright notice and this permission notice appear in all copies.      │
│                                                                              │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
│ PERFORMANCE OF THIS SOFTWARE.                                                │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/internal.h"
#include "libc/errno.h"

#define __NR_dup3_linux 0x0124 /*RHEL5:CVE-2010-3301*/

int32_t dup3$sysv(int32_t oldfd, int32_t newfd, int flags) {
  static bool once, demodernize;
  int olderr, fd;
  if (!once) {
    once = true;
    olderr = errno;
    fd = __dup3$sysv(oldfd, newfd, flags);
    if ((fd == -1 && errno == ENOSYS) || fd == __NR_dup3_linux) {
      demodernize = true;
      errno = olderr;
      goto OldSkool;
    }
  } else if (demodernize) {
    goto OldSkool;
  } else {
    fd = __dup3$sysv(oldfd, newfd, flags);
  }
  return fd;
OldSkool:
  fd = dup2$sysv(oldfd, newfd);
  if (flags) fd = fixupnewfd$sysv(fd, flags);
  return fd;
}