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/* nbdkit
* Copyright Red Hat
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* * Neither the name of Red Hat nor the names of its contributors may be
* used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/* Implement the --exit-with-parent feature on operating systems which
* support it.
*/
#include <config.h>
#include <stdlib.h>
#include <stdbool.h>
#include <signal.h>
#ifdef HAVE_SYS_PRCTL_H
#include <sys/prctl.h>
#endif
#ifdef HAVE_SYS_PROCCTL_H
#include <sys/procctl.h>
#endif
#if defined (HAVE_SYS_PRCTL_H) && defined (PR_SET_PDEATHSIG)
/* For Linux >= 2.1.57. */
int
set_exit_with_parent (void)
{
return prctl (PR_SET_PDEATHSIG, SIGTERM);
}
bool
can_exit_with_parent (void)
{
return true;
}
#elif defined (HAVE_SYS_PROCCTL_H) && defined (PROC_PDEATHSIG_CTL)
/* For FreeBSD >= 11.2 */
int
set_exit_with_parent (void)
{
const int sig = SIGTERM;
return procctl (P_PID, 0, PROC_PDEATHSIG_CTL, (void*) &sig);
}
bool
can_exit_with_parent (void)
{
return true;
}
#elif defined (__APPLE__)
/* For macOS. */
#include <unistd.h>
#include <errno.h>
#include <sys/event.h>
#include <pthread.h>
#include "nbdkit-plugin.h"
static void *
exit_with_parent_loop (void *vp)
{
const pid_t ppid = getppid ();
int fd;
struct kevent kev, res[1];
int r;
nbdkit_debug ("macOS: --exit-with-parent: "
"registering exit with parent for ppid %d",
(int) ppid);
/* Register the kevent to wait for ppid to exit. */
fd = kqueue ();
if (fd == -1) {
nbdkit_error ("exit_with_parent_loop: kqueue: %m");
return NULL;
}
EV_SET (&kev, ppid, EVFILT_PROC, EV_ADD|EV_ENABLE, NOTE_EXIT, 0, NULL);
if (kevent (fd, &kev, 1, NULL, 0, NULL) == -1) {
nbdkit_error ("exit_with_parent_loop: kevent: %m");
close (fd);
return NULL;
}
/* Wait for the kevent to happen. */
r = kevent (fd, 0, 0, res, 1, NULL);
if (r == 1 && res[0].ident == ppid) {
/* Shut down the whole process when the parent dies. */
nbdkit_debug ("macOS: --exit-with-parent: "
"exit because parent process died");
nbdkit_shutdown ();
}
return NULL;
}
int
set_exit_with_parent (void)
{
int r;
pthread_attr_t attrs;
pthread_t exit_with_parent_thread;
/* We have to block waiting for kevent, so that requires that we
* start a background thread.
*/
pthread_attr_init (&attrs);
pthread_attr_setdetachstate (&attrs, PTHREAD_CREATE_DETACHED);
r = pthread_create (&exit_with_parent_thread, NULL,
exit_with_parent_loop, NULL);
if (r != 0) {
errno = r;
return -1;
}
return 0;
}
bool
can_exit_with_parent (void)
{
return true;
}
#else /* any platform that doesn't support this function */
int
set_exit_with_parent (void)
{
abort ();
}
bool
can_exit_with_parent (void)
{
return false;
}
#endif
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