1 /* Process handling 2 * 3 * Copyright © 2013, Benoît 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 35 struct child { 36 pid_t pid; 37 time_t age; 38 struct client_cache_s *client; 39 }; 40 41 extern struct child *children; 42 extern 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 */ 50 pid_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 */ 58 void 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 */ 65 int 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 */ 74 int process_check_if_running(const char *fname); 75 76 /** 77 * Kill all child processes 78 */ 79 void process_reap_children(void); 80 81 #endif // __PROCESS_H__ 82