NetworkInador/lib/file_watcher.c

/*
 * file_watcher.c
 * This file is part of Network-inador
 *
 * Copyright (C) 2025 - Félix Arreola Rodríguez
 *
 * Network-inador is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Network-inador is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Network-inador; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, 
 * Boston, MA  02110-1301  USA
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <errno.h>

#include <sys/inotify.h>

#include "file_watcher.h"
#include "network-inador-private.h"

static void network_inador_file_watcher_deliver_event (NetworkInadorHandle *handle, struct inotify_event *event, INotifyWD *inotwd) {
	char path[4096];
	
	if (event->name[0] == 0) {
		snprintf (path, sizeof (path), "%s", inotwd->path);
	} else {
		snprintf (path, sizeof (path), "%s/%s", inotwd->path, event->name);
	}
	
	/* Este es el que pidió cierre de escritura */
	if (event->mask & IN_CLOSE_WRITE) {
		if (inotwd->close_write_cb != NULL) {
			inotwd->close_write_cb (handle, path, inotwd->close_write_data);
		}
	}
	
	if ((event->mask & IN_IGNORED) || (event->mask & IN_DELETE_SELF) || (event->mask & IN_MOVE_SELF)) {
		/* El evento fué eliminado, quitar de la lista de wds */
		handle->file_watcher.wds = f_list_remove (handle->file_watcher.wds, inotwd);
	}
}

static void network_inador_file_watcher_inotify_read_cb (void *data, int fd, int condition) {
	NetworkInadorHandle *handle = (NetworkInadorHandle *) data;
	int res, g, n;
	struct inotify_event events[20];
	FList *p, *next;
	INotifyWD *inotwd;
	
inotify_read_again:
	res = read (handle->file_watcher.inotify_fd, events, sizeof (events));
	
	/* Nada que leer */
	if (res < 0 && (errno == EAGAIN || errno == EWOULDBLOCK)) return;
	
	if (res <= 0) {
		/* El inotify fué cerrado, cancelar la vigilancia y quitar el source */
		handle->ops.input_remove (handle->file_watcher.inotify_source);
		handle->file_watcher.inotify_source = 0;
		
		f_list_free_full (handle->file_watcher.wds, free);
		handle->file_watcher.has_inotify = FALSE;
		
		close (handle->file_watcher.inotify_fd);
		handle->file_watcher.inotify_fd = -1;
		return;
	}
	
	n = res / sizeof (events[0]);
	
	for (g = 0; g < n; g++) {
		p = handle->file_watcher.wds;
		while (p != NULL) {
			next = p->next;
			inotwd = (INotifyWD *) p->data;
			
			if (inotwd->inotify_wd == events[g].wd) {
				network_inador_file_watcher_deliver_event (handle, &events[g], inotwd);
				break;
			}
			p = next;
		}
	}
	
	if (res == sizeof (events)) goto inotify_read_again;
}

void network_inador_file_watcher_init (NetworkInadorHandle *handle) {
	int fd;
	
	if (handle->ops.input_add != NULL) {
		/* Como tenemos vigilancia de fds, podemos intentar inicializar el inotify */
		fd = inotify_init1 (IN_NONBLOCK | IN_CLOEXEC);
		
		if (fd < 0) {
			handle->file_watcher.has_inotify = FALSE;
			handle->file_watcher.inotify_fd = -1;
			return;
		}
		
		handle->file_watcher.inotify_source = handle->ops.input_add (fd, POLLIN, network_inador_file_watcher_inotify_read_cb, handle);
		
		handle->file_watcher.has_inotify = TRUE;
		handle->file_watcher.inotify_fd = fd;
	}
}

void network_inador_file_watcher_add_file (NetworkInadorHandle *handle, const char *path, FileWatcherCloseWriteCB close_write_cb, void *close_write_data) {
	int res, wd;
	INotifyWD *inotwd;
	
	if (handle->file_watcher.has_inotify == FALSE) return;
	
	wd = inotify_add_watch (handle->file_watcher.inotify_fd, path, IN_CLOSE_WRITE | IN_DELETE_SELF | IN_MOVE_SELF);
	
	if (wd < 0) return; /* No lo pude agregar */
	
	inotwd = (INotifyWD *) malloc (sizeof (INotifyWD));
	if (inotwd == NULL) {
		inotify_rm_watch (handle->file_watcher.inotify_fd, wd);
		
		return;
	}
	
	memset (inotwd, 0, sizeof (INotifyWD));
	inotwd->inotify_wd = wd;
	inotwd->close_write_cb = close_write_cb;
	inotwd->close_write_data = close_write_data;
	
	strncpy (inotwd->path, path, sizeof (inotwd->path));
	
	handle->file_watcher.wds = f_list_append (handle->file_watcher.wds, inotwd);
}

void network_inador_file_watcher_cleanup (NetworkInadorHandle *handle) {
	if (handle->file_watcher.has_inotify) {
		close (handle->file_watcher.inotify_fd);
		handle->file_watcher.inotify_fd = -1;
		
		if (handle->file_watcher.inotify_source != 0 && handle->ops.input_remove != NULL) {
			handle->ops.input_remove (handle->file_watcher.inotify_source);
			handle->file_watcher.inotify_source = 0;
		}
	}
}