1 /* 2 * Amanda, The Advanced Maryland Automatic Network Disk Archiver 3 * Copyright (c) 1999 University of Maryland at College Park 4 * Copyright (c) 2007-2013 Zmanda, Inc. All Rights Reserved. 5 * All Rights Reserved. 6 * 7 * Permission to use, copy, modify, distribute, and sell this software and its 8 * documentation for any purpose is hereby granted without fee, provided that 9 * the above copyright notice appear in all copies and that both that 10 * copyright notice and this permission notice appear in supporting 11 * documentation, and that the name of U.M. not be used in advertising or 12 * publicity pertaining to distribution of the software without specific, 13 * written prior permission. U.M. makes no representations about the 14 * suitability of this software for any purpose. It is provided "as is" 15 * without express or implied warranty. 16 * 17 * U.M. DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL U.M. 19 * BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 20 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION 21 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN 22 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 23 * 24 * Authors: the Amanda Development Team. Its members are listed in a 25 * file named AUTHORS, in the root directory of this distribution. 26 */ 27 /* 28 * $Id: event.h,v 1.9 2006/06/16 10:55:05 martinea Exp $ 29 */ 30 #ifndef EVENT_H 31 #define EVENT_H 32 33 /* 34 * These functions define a generic event interface. One can register a 35 * function vector and the type of events to act on, and the event handler 36 * will dispatch as necessary. 37 */ 38 39 /* 40 * An opaque handle returned by the registry functions that can be 41 * used to unregister an event in the future. 42 */ 43 struct event_handle; 44 typedef struct event_handle event_handle_t; 45 46 /* 47 * The 'id' of the event. The meaning of this depends on the type of 48 * event we are registering -- see event_register. The name 'id' is 49 * historical: it is quite possible to have many outstanding events with 50 * the same ID (same timeout or same file descriptor). 51 * 52 * Event id's are supplied by the caller, and in some cases are cast from 53 * pointers, so this value must be wide enough to hold a pointer without 54 * truncation. 55 */ 56 typedef intmax_t event_id_t; 57 58 /* 59 * The types of events we can register. 60 */ 61 typedef enum { 62 EV_READFD, /* file descriptor is ready for reading */ 63 EV_WRITEFD, /* file descriptor is ready for writing */ 64 EV_TIME, /* n seconds have elapsed */ 65 EV_WAIT, /* event_wakeup() was called with this id */ 66 } event_type_t; 67 68 /* 69 * The function signature for functions that get called when an event 70 * fires. 71 */ 72 typedef void (*event_fn_t)(void *); 73 74 /* 75 * Register an event handler. 76 * 77 * For readfd and writefd events, the first arg is the file descriptor. 78 * There can be multiple callers firing on the same file descriptor. 79 * 80 * For signal events, the first arg is the signal number as defined in 81 * <signal.h>. There can only be one signal handler. (do we need more?) 82 * 83 * For time events, the first arg is the interval in seconds between 84 * pulses. There can be multiple time events, of course. Don't 85 * count on the time events being too accurate. They depend on the 86 * caller calling event_loop() often enough. 87 */ 88 event_handle_t *event_register(event_id_t, event_type_t, event_fn_t, void *); 89 event_handle_t *event_create(event_id_t, event_type_t, event_fn_t, void *); 90 void event_activate(event_handle_t *); 91 92 /* 93 * Release an event handler. 94 */ 95 void event_release(event_handle_t *); 96 97 /* 98 * Wake up all EV_WAIT events waiting on a specific id. This happens immediately, 99 * not in the next iteration of the event loop. If callbacks made during the wakeup 100 * register a new event with the same ID, that new event will *not* be awakened. 101 */ 102 int event_wakeup(event_id_t); 103 104 /* 105 * Call event_loop, returning when one of the following conditions is 106 * true: 107 * evt is EV_WAIT, and it is released; or 108 * evt is EV_READFD, EV_WRITEFD, or EV_TIME, and it is fired. 109 */ 110 void event_wait(event_handle_t *evt); 111 112 /* 113 * Process events. If the argument is nonzero, then the loop does 114 * not block. 115 */ 116 void event_loop(int nonblock); 117 118 /* 119 * Get the default GMainLoop object. Applications which use the Glib 120 * main loop directly should use this object for calls to e.g., 121 * g_main_loop_run(loop). 122 */ 123 GMainLoop *default_main_loop(void); 124 125 /* 126 * Utility GSources 127 */ 128 129 /* Create a GSource that will callback when the given file descriptor is in 130 * any of the given conditions. The callback is a simple GSourceFunc. 131 * 132 * @param fd: the file descriptr 133 * @param events: the conditions (GIOCondition flags) 134 * @return: GSource object 135 */ 136 GSource * new_fdsource(gint fd, GIOCondition events); 137 138 /* Create a GSource that will callback when the given child dies. The callback 139 * should match ChildWatchFunc. Once the callback is made, it will not be called 140 * again by this source. 141 * 142 * Note: This is provided by glib in later versions, but not in version 2.2.0. 143 * This function and callback is modeled on g_child_watch_source_new. 144 * 145 * @param pid: the process ID @return: GSource object 146 */ 147 typedef void (*ChildWatchFunc)(pid_t pid, gint status, gpointer data); 148 GSource * new_child_watch_source(pid_t pid); 149 150 #endif /* EVENT_H */ 151