1/* Process handling
2 *
3 * Copyright �� 2013, Beno��t Knecht <benoit.knecht@fsfe.org>
4 *
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions are met:
9 *     * Redistributions of source code must retain the above copyright
10 *       notice, this list of conditions and the following disclaimer.
11 *     * Redistributions in binary form must reproduce the above copyright
12 *       notice, this list of conditions and the following disclaimer in the
13 *       documentation and/or other materials provided with the distribution.
14 *     * The name of the author may not be used to endorse or promote products
15 *       derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
18 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
21 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
22 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
25 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
27 * POSSIBILITY OF SUCH DAMAGE.
28 */
29#ifndef __PROCESS_H__
30#define __PROCESS_H__
31
32#include <unistd.h>
33#include "clients.h"
34
35struct child {
36	pid_t pid;
37	time_t age;
38	struct client_cache_s *client;
39};
40
41extern struct child *children;
42extern int number_of_children;
43
44/**
45 * Fork a new child (just like fork()) but keep track of how many childs are
46 * already running, and refuse fo fork if there are too many.
47 * @return -1 if it couldn't fork, 0 in the child process, the pid of the
48 *         child process in the parent process.
49 */
50pid_t process_fork(struct client_cache_s *client);
51
52/**
53 * Handler to be called upon receiving SIGCHLD. This signal is received by the
54 * parent process when a child terminates, and this handler updates the number
55 * of running childs accordingly.
56 * @param signal The signal number.
57 */
58void process_handle_child_termination(int signal);
59
60/**
61 * Daemonize the current process by forking itself and redirecting standard
62 * input, standard output and standard error to /dev/null.
63 * @return The pid of the process.
64 */
65int process_daemonize(void);
66
67/**
68 * Check if the process corresponding to the pid found in the pid file is
69 * running.
70 * @param fname The path to the pid file.
71 * @return 0 if no other instance is running, -1 if the file name is invalid,
72 *         -2 if another instance is running.
73 */
74int process_check_if_running(const char *fname);
75
76/**
77 * Kill all child processes
78 */
79void process_reap_children(void);
80
81#endif // __PROCESS_H__
82