/*

 * CDDL HEADER START

 *

 * The contents of this file are subject to the terms of the

 * Common Development and Distribution License, Version 1.0 only

 * (the "License").  You may not use this file except in compliance

 * with the License.

 *

 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE

 * or http://www.opensolaris.org/os/licensing.

 * See the License for the specific language governing permissions

 * and limitations under the License.

 *

 * When distributing Covered Code, include this CDDL HEADER in each

 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.

 * If applicable, add the following below this CDDL HEADER, with the

 * fields enclosed by brackets "[]" replaced with your own identifying

 * information: Portions Copyright [yyyy] [name of copyright owner]

 *

 * CDDL HEADER END

 */

/*

 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.

 * Use is subject to license terms.

 */

#pragma ident	"%Z%%M%	%I%	%E% SMI"

/*

 * wait.c - asynchronous monitoring of "wait registered" start methods

 *

 * Use event ports to poll on the set of fds representing the /proc/[pid]/psinfo

 * files.  If one of these fds returns an event, then we inform the restarter

 * that it has stopped.

 *

 * The wait_info_list holds the series of processes currently being monitored

 * for exit.  The wi_fd member, which contains the file descriptor of the psinfo

 * file being polled upon ("event ported upon"), will be set to -1 if the file

 * descriptor is inactive (already closed or not yet opened).

 */

#ifdef _FILE_OFFSET_BITS

#undef _FILE_OFFSET_BITS

#endif /* _FILE_OFFSET_BITS */

#include <sys/resource.h>

#include <sys/stat.h>

#include <sys/types.h>

#include <sys/uio.h>

#include <sys/wait.h>

#include <assert.h>

#include <errno.h>

#include <fcntl.h>

#include <libuutil.h>

#include <poll.h>

#include <port.h>

#include <pthread.h>

#include <procfs.h>

#include <string.h>

#include <stropts.h>

#include <unistd.h>

#include "startd.h"

#define	WAIT_FILES	262144		/* reasonably high maximum */

static int port_fd;

static scf_handle_t *wait_hndl;

static struct rlimit init_fd_rlimit;

static uu_list_pool_t *wait_info_pool;

static uu_list_t *wait_info_list;

static pthread_mutex_t wait_info_lock;

/*

 * void wait_remove(wait_info_t *, int)

 *   Remove the given wait_info structure from our list, performing various

 *   cleanup operations along the way.  If the direct flag is false (meaning

 *   that we are being called with from restarter instance list context), then

 *   notify the restarter that the associated instance has exited.

 *

 *   Since we may no longer be the startd that started this process, we only are

 *   concerned with a waitpid(3C) failure if the wi_parent field is non-zero.

 */

static void

wait_remove(wait_info_t *wi, int direct)

{

	int status;

	if (waitpid(wi->wi_pid, &status, 0) == -1) {

		if (wi->wi_parent)

			log_framework(LOG_INFO,

			    "instance %s waitpid failure: %s\n", wi->wi_fmri,

			    strerror(errno));

	} else {

		if (WEXITSTATUS(status) != 0) {

			log_framework(LOG_NOTICE,

			    "instance %s exited with status %d\n", wi->wi_fmri,

			    WEXITSTATUS(status));

		}

	}

	MUTEX_LOCK(&wait_info_lock);

	if (wi->wi_fd != -1) {

		startd_close(wi->wi_fd);

		wi->wi_fd = -1;

	}

	uu_list_remove(wait_info_list, wi);

	MUTEX_UNLOCK(&wait_info_lock);

	/*

	 * Make an attempt to clear out any utmpx record associated with this

	 * PID.

	 */

	utmpx_mark_dead(wi->wi_pid, status, B_FALSE);

	if (!direct) {

		/*

		 * Bind wait_hndl lazily.

		 */

		if (wait_hndl == NULL) {

			for (wait_hndl =

			    libscf_handle_create_bound(SCF_VERSION);

			    wait_hndl == NULL;

			    wait_hndl =

			    libscf_handle_create_bound(SCF_VERSION)) {

				log_error(LOG_INFO, "[wait_remove] Unable to "

				    "bind a new repository handle: %s\n",

				    scf_strerror(scf_error()));

				(void) sleep(2);

			}

		}

		log_framework(LOG_DEBUG,

		    "wait_remove requesting stop of %s\n", wi->wi_fmri);

		(void) stop_instance_fmri(wait_hndl, wi->wi_fmri, RSTOP_EXIT);

	}

	uu_list_node_fini(wi, &wi->wi_link, wait_info_pool);

	startd_free(wi, sizeof (wait_info_t));

}

/*

 * int wait_register(pid_t, char *, int, int)

 *   wait_register is called after we have called fork(2), and know which pid we

 *   wish to monitor.  However, since the child may have already exited by the

 *   time we are called, we must handle the error cases from open(2)

 *   appropriately.  The am_parent flag is recorded to handle waitpid(2)

 *   behaviour on removal; similarly, the direct flag is passed through to a

 *   potential call to wait_remove() to govern its behaviour in different

 *   contexts.

 *

 *   Returns 0 if registration successful, 1 if child pid did not exist, and -1

 *   if a different error occurred.

 */

int

wait_register(pid_t pid, const char *inst_fmri, int am_parent, int direct)

{

	char *fname = uu_msprintf("/proc/%ld/psinfo", pid);

	int fd;

	wait_info_t *wi;

	assert(pid != 0);

	if (fname == NULL)

		return (-1);

	wi = startd_alloc(sizeof (wait_info_t));

	uu_list_node_init(wi, &wi->wi_link, wait_info_pool);

	wi->wi_fd = -1;

	wi->wi_pid = pid;

	wi->wi_fmri = inst_fmri;

	wi->wi_parent = am_parent;

	MUTEX_LOCK(&wait_info_lock);

	(void) uu_list_insert_before(wait_info_list, NULL, wi);

	MUTEX_UNLOCK(&wait_info_lock);

	if ((fd = open(fname, O_RDONLY)) == -1) {

		if (errno == ENOENT) {

			/*

			 * Child has already exited.

			 */

			wait_remove(wi, direct);

			uu_free(fname);

			return (1);

		} else {

			log_error(LOG_WARNING,

			    "open %s failed; not monitoring %s: %s\n", fname,

			    inst_fmri, strerror(errno));

			uu_free(fname);

			return (-1);

		}

	}

	uu_free(fname);

	wi->wi_fd = fd;

	if (port_associate(port_fd, PORT_SOURCE_FD, fd, 0, wi)) {

		log_error(LOG_WARNING,

		    "initial port_association of %d / %s failed: %s\n", fd,

		    inst_fmri, strerror(errno));

		return (-1);

	}

	log_framework(LOG_DEBUG, "monitoring PID %ld on fd %d (%s)\n", pid, fd,

	    inst_fmri);

	return (0);

}

/*ARGSUSED*/

void *

wait_thread(void *args)

{

	for (;;) {

		port_event_t pe;

		int fd;

		wait_info_t *wi;

		if (port_get(port_fd, &pe, NULL) != 0) {

			if (errno == EINTR)

				continue;

			else {

				log_error(LOG_WARNING,

				    "port_get() failed with %s\n",

				    strerror(errno));

				bad_error("port_get", errno);

			}

		}

		fd = pe.portev_object;

		wi = pe.portev_user;

		assert(wi != NULL);

		assert(fd == wi->wi_fd);

		if ((pe.portev_events & POLLHUP) == POLLHUP) {

			psinfo_t psi;

			if (lseek(fd, 0, SEEK_SET) != 0 ||

			    read(fd, &psi, sizeof (psinfo_t)) !=

			    sizeof (psinfo_t)) {

				log_framework(LOG_WARNING,

				    "couldn't get psinfo data for %s (%s); "

				    "assuming failed\n", wi->wi_fmri,

				    strerror(errno));

				    goto err_remove;

			}

			if (psi.pr_nlwp != 0 ||

			    psi.pr_nzomb != 0 ||

			    psi.pr_lwp.pr_lwpid != 0) {

				/*

				 * We have determined, in accordance with the

				 * definition in proc(4), this process is not a

				 * zombie.  Reassociate.

				 */

				if (port_associate(port_fd, PORT_SOURCE_FD, fd,

					0, wi))

					log_error(LOG_WARNING,

					    "port_association of %d / %s "

					    "failed\n", fd, wi->wi_fmri);

				continue;

			}

		} else if (

		    (pe.portev_events & POLLERR) == 0) {

			if (port_associate(port_fd, PORT_SOURCE_FD, fd, 0, wi))

				log_error(LOG_WARNING,

				    "port_association of %d / %s "

				    "failed\n", fd, wi->wi_fmri);

			continue;

		}

err_remove:

		wait_remove(wi, 0);

	}

	/*LINTED E_FUNC_HAS_NO_RETURN_STMT*/

}

void

wait_prefork()

{

	MUTEX_LOCK(&wait_info_lock);

}

void

wait_postfork(pid_t pid)

{

	wait_info_t *wi;

	MUTEX_UNLOCK(&wait_info_lock);

	if (pid != 0)

		return;

	/*

	 * Close all of the child's wait-related fds.  The wait_thread() is

	 * gone, so no need to worry about returning events.  We always exec(2)

	 * after a fork request, so we needn't free the list elements

	 * themselves.

	 */

	for (wi = uu_list_first(wait_info_list);

	    wi != NULL;

	    wi = uu_list_next(wait_info_list, wi)) {

		if (wi->wi_fd != -1)

			startd_close(wi->wi_fd);

	}

	startd_close(port_fd);

	(void) setrlimit(RLIMIT_NOFILE, &init_fd_rlimit);

}

void

wait_init()

{

	struct rlimit fd_new;

	(void) getrlimit(RLIMIT_NOFILE, &init_fd_rlimit);

	(void) getrlimit(RLIMIT_NOFILE, &fd_new);

	fd_new.rlim_max = fd_new.rlim_cur = WAIT_FILES;

	(void) setrlimit(RLIMIT_NOFILE, &fd_new);

	if ((port_fd = port_create()) == -1)

		uu_die("wait_init couldn't port_create");

	wait_info_pool = uu_list_pool_create("wait_info", sizeof (wait_info_t),

	    offsetof(wait_info_t, wi_link), NULL, UU_LIST_POOL_DEBUG);

	if (wait_info_pool == NULL)

		uu_die("wait_init couldn't create wait_info_pool");

	wait_info_list = uu_list_create(wait_info_pool, wait_info_list, 0);

	if (wait_info_list == NULL)

		uu_die("wait_init couldn't create wait_info_list");

	(void) pthread_mutex_init(&wait_info_lock, &mutex_attrs);

}