| 1 | /* |
| 2 | * QEMU file monitor helper |
| 3 | * |
| 4 | * Copyright (c) 2018 Red Hat, Inc. |
| 5 | * |
| 6 | * This library is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU Lesser General Public |
| 8 | * License as published by the Free Software Foundation; either |
| 9 | * version 2.1 of the License, or (at your option) any later version. |
| 10 | * |
| 11 | * This library is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 14 | * Lesser General Public License for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU Lesser General Public |
| 17 | * License along with this library; if not, see <http://www.gnu.org/licenses/>. |
| 18 | * |
| 19 | */ |
| 20 | |
| 21 | #ifndef QEMU_FILEMONITOR_H |
| 22 | #define QEMU_FILEMONITOR_H |
| 23 | |
| 24 | |
| 25 | |
| 26 | typedef struct QFileMonitor QFileMonitor; |
| 27 | |
| 28 | typedef enum { |
| 29 | /* File has been created in a dir */ |
| 30 | QFILE_MONITOR_EVENT_CREATED, |
| 31 | /* File has been modified in a dir */ |
| 32 | QFILE_MONITOR_EVENT_MODIFIED, |
| 33 | /* File has been deleted in a dir */ |
| 34 | QFILE_MONITOR_EVENT_DELETED, |
| 35 | /* File has attributes changed */ |
| 36 | QFILE_MONITOR_EVENT_ATTRIBUTES, |
| 37 | /* Dir is no longer being monitored (due to deletion) */ |
| 38 | QFILE_MONITOR_EVENT_IGNORED, |
| 39 | } QFileMonitorEvent; |
| 40 | |
| 41 | |
| 42 | /** |
| 43 | * QFileMonitorHandler: |
| 44 | * @id: id from qemu_file_monitor_add_watch() |
| 45 | * @event: the file change that occurred |
| 46 | * @filename: the name of the file affected |
| 47 | * @opaque: opaque data provided to qemu_file_monitor_add_watch() |
| 48 | * |
| 49 | * Invoked whenever a file changes. If @event is |
| 50 | * QFILE_MONITOR_EVENT_IGNORED, @filename will be |
| 51 | * empty. |
| 52 | * |
| 53 | */ |
| 54 | typedef void (*QFileMonitorHandler)(int64_t id, |
| 55 | QFileMonitorEvent event, |
| 56 | const char *filename, |
| 57 | void *opaque); |
| 58 | |
| 59 | /** |
| 60 | * qemu_file_monitor_new: |
| 61 | * @errp: pointer to a NULL-initialized error object |
| 62 | * |
| 63 | * Create a handle for a file monitoring object. |
| 64 | * |
| 65 | * This object does locking internally to enable it to be |
| 66 | * safe to use from multiple threads |
| 67 | * |
| 68 | * If the platform does not support file monitoring, an |
| 69 | * error will be reported. Likewise if file monitoring |
| 70 | * is supported, but cannot be initialized |
| 71 | * |
| 72 | * Currently this is implemented on Linux platforms with |
| 73 | * the inotify subsystem. |
| 74 | * |
| 75 | * Returns: the new monitoring object, or NULL on error |
| 76 | */ |
| 77 | QFileMonitor *qemu_file_monitor_new(Error **errp); |
| 78 | |
| 79 | /** |
| 80 | * qemu_file_monitor_free: |
| 81 | * @mon: the file monitor context |
| 82 | * |
| 83 | * Free resources associated with the file monitor, |
| 84 | * including any currently registered watches. |
| 85 | */ |
| 86 | void qemu_file_monitor_free(QFileMonitor *mon); |
| 87 | |
| 88 | /** |
| 89 | * qemu_file_monitor_add_watch: |
| 90 | * @mon: the file monitor context |
| 91 | * @dirpath: the directory whose contents to watch |
| 92 | * @filename: optional filename to filter on |
| 93 | * @cb: the function to invoke when @dirpath has changes |
| 94 | * @opaque: data to pass to @cb |
| 95 | * @errp: pointer to a NULL-initialized error object |
| 96 | * |
| 97 | * Register to receive notifications of changes |
| 98 | * in the directory @dirpath. All files in the |
| 99 | * directory will be monitored. If the caller is |
| 100 | * only interested in one specific file, @filename |
| 101 | * can be used to filter events. |
| 102 | * |
| 103 | * Returns: a positive integer watch ID, or -1 on error |
| 104 | */ |
| 105 | int64_t qemu_file_monitor_add_watch(QFileMonitor *mon, |
| 106 | const char *dirpath, |
| 107 | const char *filename, |
| 108 | QFileMonitorHandler cb, |
| 109 | void *opaque, |
| 110 | Error **errp); |
| 111 | |
| 112 | /** |
| 113 | * qemu_file_monitor_remove_watch: |
| 114 | * @mon: the file monitor context |
| 115 | * @dirpath: the directory whose contents to unwatch |
| 116 | * @id: id of the watch to remove |
| 117 | * |
| 118 | * Removes the file monitoring watch @id, associated |
| 119 | * with the directory @dirpath. This must never be |
| 120 | * called from a QFileMonitorHandler callback, or a |
| 121 | * deadlock will result. |
| 122 | */ |
| 123 | void qemu_file_monitor_remove_watch(QFileMonitor *mon, |
| 124 | const char *dirpath, |
| 125 | int64_t id); |
| 126 | |
| 127 | #endif /* QEMU_FILEMONITOR_H */ |