alcove

/* 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_fork.h"

/*
 * fork(2)
 *
 */
ssize_t alcove_sys_fork(alcove_state_t *ap, const char *arg, size_t len,
                        char *reply, size_t rlen) {
  int rindex = 0;

  alcove_arg_t child_arg = {0};
  alcove_stdio_t fd = {0};
  pid_t pid = 0;
  sigset_t oldset;
  sigset_t set;
  int errnum = 0;

  UNUSED(arg);
  UNUSED(len);

  if (ap->depth >= ap->maxforkdepth)
    return alcove_mk_errno(reply, rlen, EAGAIN);

  if (pid_foreach(ap, 0, NULL, NULL, pid_equal, avail_pid) != 0)
    return alcove_mk_errno(reply, rlen, EAGAIN);

  if (alcove_stdio(&fd) < 0)
    return alcove_mk_errno(reply, rlen, errno);

  (void)sigfillset(&set);
  (void)sigemptyset(&oldset);

  if (sigprocmask(SIG_BLOCK, &set, &oldset) < 0)
    return alcove_mk_errno(reply, rlen, errno);

  child_arg.ap = ap;
  child_arg.fd = &fd;
  child_arg.sigset = &oldset;

  pid = fork();

  switch (pid) {
  case -1:
    errnum = errno;
    if (sigprocmask(SIG_SETMASK, &oldset, NULL) < 0)
      exit(errno);
    return alcove_mk_errno(reply, rlen, errnum);
  case 0:
    if (alcove_child_fun(&child_arg) < 0)
      exit(errno);
    exit(0);
  default:
    if (sigprocmask(SIG_SETMASK, &oldset, NULL) < 0)
      return alcove_mk_errno(reply, rlen, errno);

    if (alcove_parent_fd(ap, &fd, pid) < 0)
      return alcove_mk_errno(reply, rlen, errno);

    ALCOVE_OK(reply, rlen, &rindex,
              alcove_encode_long(reply, rlen, &rindex, pid));

    return rindex;
  }
}