/* 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 <sys/mount.h>

#include "alcove_mount_constants.h"

#define MAYBE_NULL(_len, _buf) ((_len) == 0 ? NULL : (_buf))

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

  char source[PATH_MAX] = {0};
  size_t slen = sizeof(source) - 1;
  char target[PATH_MAX] = {0};
  size_t tlen = sizeof(target) - 1;
  char filesystemtype[PATH_MAX] = {0};
  size_t flen = sizeof(filesystemtype) - 1;
  unsigned long mountflags = 0;
  int val = 0;
  char data[MAXMSGLEN] = {0};
  size_t dlen = sizeof(data);
  char opt[MAXMSGLEN] = {0};
  size_t olen = sizeof(opt);

  int rv = 0;

  UNUSED(ap);

  /* source */
  if (alcove_decode_iolist(arg, len, &index, source, &slen) < 0)
    return -1;

  /* target */
  if (alcove_decode_iolist(arg, len, &index, target, &tlen) < 0 || tlen == 0)
    return -1;

  /* filesystemtype */
  if (alcove_decode_iolist(arg, len, &index, filesystemtype, &flen) < 0)
    return -1;

  /* mountflags */
  switch (alcove_decode_constant_list(arg, len, &index, &val,
                                      alcove_mount_constants)) {
  case 0:
    if (val < 0)
      return -1;

    mountflags = val;
    break;
  case 1:
    return alcove_mk_error(reply, rlen, "enotsup");
  default:
    return -1;
  }

  /* data */
  if (alcove_decode_iolist(arg, len, &index, data, &dlen) < 0)
    return -1;

  /* options */
  if (alcove_decode_iolist(arg, len, &index, opt, &olen) < 0)
    return -1;

#ifdef __linux__
  rv = mount(MAYBE_NULL(slen, source), target, MAYBE_NULL(flen, filesystemtype),
             mountflags, MAYBE_NULL(dlen, data));
#elif defined(__sunos__)
  /* The option buffer is input/output with the mount options placed
   * in the buf on return. The option buffer must be large enough to
   * hold the returned options string.
   *
   * * if the buffer is too small, the return value is {error,eoverflow}
   *   and the mount is successful
   *
   * * if the buffer is too large(?), the return value is {error,einval}
   *   and the mount fails
   */
  rv = mount(MAYBE_NULL(slen, source), target, mountflags,
             MAYBE_NULL(flen, filesystemtype), MAYBE_NULL(dlen, data), dlen,
             MAYBE_NULL(olen, opt), olen);
#else
  rv = mount(MAYBE_NULL(flen, filesystemtype), target, mountflags,
             MAYBE_NULL(dlen, data)
#ifdef __NetBSD__
                 ,
             dlen
#endif
  );
#endif

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