alcove

/* Copyright (c) 2015, 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"

#ifdef __linux__
#include "grp.h"
#endif

static int alcove_list_to_groups(const char *arg, size_t len, int *index,
                                 int type, gid_t *list, int arity);

/*
 * setgroups(2)
 *
 */
ssize_t alcove_sys_setgroups(alcove_state_t *ap, const char *arg, size_t len,
                             char *reply, size_t rlen) {
  int index = 0;
  gid_t *list = NULL;
  int n;

  int type = 0;
  int arity = 0;

  UNUSED(ap);

  if (alcove_get_type(arg, len, &index, &type, &arity) < 0)
    return -1;

  if (arity > 0) {
    list = calloc(arity, sizeof(gid_t));
    if (list == NULL)
      return alcove_mk_errno(reply, rlen, errno);
  }

  if (alcove_list_to_groups(arg, len, &index, type, list, arity) < 0) {
    free(list);
    return -1;
  }

  n = setgroups(arity, list);

  if (n < 0) {
    free(list);
    return alcove_mk_errno(reply, rlen, errno);
  }

  free(list);

  return alcove_mk_atom(reply, rlen, "ok");
}

static int alcove_list_to_groups(const char *arg, size_t len, int *index,
                                 int type, gid_t *list, int arity) {
  int n = 0;

  switch (type) {
  case ERL_STRING_EXT: {
    char *tmp = NULL;

    tmp = calloc(arity + 1, 1);
    if (tmp == NULL)
      return -1;

    if (alcove_decode_string(arg, len, index, tmp, arity + 1) < 0) {
      free(tmp);
      return -1;
    }

    for (n = 0; n < arity; n++)
      list[n] = tmp[n];

    free(tmp);
  } break;

  case ERL_LIST_EXT:
    if ((alcove_decode_list_header(arg, len, index, &n) < 0) || n != arity)
      return -1;

    for (n = 0; n < arity; n++) {
      gid_t gid = 0;

      if (alcove_decode_uint(arg, len, index, &gid) < 0)
        return -1;

      list[n] = gid;
    }

    /* ignore the list tail */
    break;

  case ERL_NIL_EXT:
    break;

  default:
    return -1;
  }

  return 0;
}