/* Copyright (c) 2014-2017, Michael Santos <michael.santos@gmail.com>
 *
 * 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 "alcove.h"
#include "alcove_call.h"

#include "alcove_rlimit_constants.h"

#if defined(__linux__) || defined(__sunos__) || defined(__OpenBSD__)
static int rlimit_under_maxfd(long maxfd, unsigned long long fd);
#endif

/*
 * setrlimit(2)
 *
 */
ssize_t alcove_sys_setrlimit(alcove_state_t *ap, const char *arg, size_t len,
                             char *reply, size_t rlen) {
  int index = 0;
  int arity = 0;

  int resource = 0;
  char atom[MAXATOMLEN] = {0};
  unsigned long long cur = 0, max = 0;
  struct rlimit rlim = {0};
  int rv = 0;

  UNUSED(ap);

  /* resource */
  switch (alcove_decode_constant(arg, len, &index, &resource,
                                 alcove_rlimit_constants)) {
  case 0:
    break;
  case 1:
    return alcove_mk_error(reply, rlen, "enotsup");
  default:
    return -1;
  }

  /* {alcove_rlimit, rlim_cur, rlim_max} */
  if (alcove_decode_tuple_header(arg, len, &index, &arity) < 0 || arity != 3)
    return -1;

  /* 'alcove_rlimit' */
  if (alcove_decode_atom(arg, len, &index, atom) < 0 ||
      strcmp(atom, "alcove_rlimit") != 0)
    return -1;

  /* rlim_cur: soft limit */
  if (alcove_decode_ulonglong(arg, len, &index, &cur) < 0)
    return -1;

  /* rlim_max: hard limit */
  if (alcove_decode_ulonglong(arg, len, &index, &max) < 0)
    return -1;

#if defined(__linux__) || defined(__sunos__) || defined(__OpenBSD__)
  if (resource == RLIMIT_NOFILE) {
    if (rlimit_under_maxfd(ap->maxfd, cur) < 0)
      return alcove_mk_errno(reply, rlen, EINVAL);
  }
#endif

  rlim.rlim_cur = cur;
  rlim.rlim_max = max;

  rv = setrlimit(resource, &rlim);

  return (rv < 0) ? alcove_mk_errno(reply, rlen, errno)
                  : alcove_mk_atom(reply, rlen, "ok");
}

#if defined(__linux__) || defined(__sunos__) || defined(__OpenBSD__)
static int rlimit_under_maxfd(long maxfd, unsigned long long fd) {
  int i;

  for (i = fd + 1; i < maxfd; i++) {
    if (fcntl(fd, F_GETFD, 0) >= 0)
      return -1;
  }

  return 0;
}
#endif