notify_u.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <sys/inotify.h>
#include <errno.h>

int notify_main(int argc, char *argv[]) {
	int nfd, ffd;
	int res;
	char event_buf[512];
	struct inotify_event *event;
	int event_mask = IN_ALL_EVENTS;
	int event_count = 1;
	int print_files = 0;
	int verbose = 2;
	int width = 80;
	char **file_names;
	int file_count;
	int id_offset = 0;
	int i;
	char *buf;

	while(1) {
		int c = getopt(argc, argv, "m:c:pv:w:");
		if(c == EOF) break;
		switch (c) {
			case 'm':
				event_mask = strtol(optarg, NULL, 0);
				break;
			case 'c':
				event_count = atoi(optarg);
				break;
			case 'p':
				print_files = 1;
				break;
			case 'v':
				verbose = atoi(optarg);
				break;
			case 'w':
				width = atoi(optarg);
				break;
			case '?':
				fprintf(stderr, "%s: invalid option -%c\n",
						argv[0], optopt);
				return 1;
		}
	}

	if (argc <= optind) {
		fprintf(stderr, "Usage: %s [-m <eventmask>] [-c <count>] [-p] [-v <verbosity>] <path> [<path>] [...]\n", argv[0]);
		return 1;
	}

	nfd = inotify_init();
	if(nfd < 0) {
		fprintf(stderr, "inotify_init failed, %s\n", strerror(errno));
		return 1;
	}
	file_names = argv + optind;
	file_count = argc - optind;
	for(i = 0; i < file_count; i++) {
		res = inotify_add_watch(nfd, file_names[i], event_mask);
		if(res < 0) {
			fprintf(stderr, "inotify_add_watch failed for %s, %s\n", file_names[i], strerror(errno));
			return 1;
		}
		if(i == 0)
			id_offset = -res;
		if(res + id_offset != i) {
			fprintf(stderr, "%s got unexpected id %d instead of %d\n", file_names[i], res, i);
			return 1;
		}
	}

	buf = malloc(width + 2);

	while(1) {
		int event_pos = 0;
		res = read(nfd, event_buf, sizeof(event_buf));
		if(res < (int)sizeof(*event)) {
			if(errno == EINTR) continue;
			fprintf(stderr, "could not get event, %s\n", strerror(errno));
			return 1;
		}
		//printf("got %d bytes of event information\n", res);
		while(res >= (int)sizeof(*event)) {
			int event_size;
			event = (struct inotify_event *)(event_buf + event_pos);
			if(verbose >= 2) {
				printf("%s: %08x %08x \"%s\"\n", file_names[event->wd + id_offset], event->mask, event->cookie, event->len ? event->name : "");
			} else if(verbose >= 1) {
				printf("%d: %08x \"%s\"\n", event->wd, event->mask, event->len ? event->name : "");
			}
			if(print_files && (event->mask & IN_MODIFY)) {
				char filename[512];
				ssize_t read_len;
				char *display_name;
				int buflen;
				strcpy(filename, file_names[event->wd + id_offset]);
				if(event->len) {
					strcat(filename, "/");
					strcat(filename, event->name);
				}
				ffd = open(filename, O_RDONLY);
				display_name = (verbose >= 2 || event->len == 0) ? filename : event->name;
				buflen = width - strlen(display_name);
				read_len = read(ffd, buf, buflen);
				if(read_len > 0) {
					if(read_len < buflen && buf[read_len-1] != '\n') {
						buf[read_len] = '\n';
						read_len++;
					}
					if(read_len == buflen) {
						buf[--read_len] = '\0';
						buf[--read_len] = '\n';
						buf[--read_len] = '.';
						buf[--read_len] = '.';
						buf[--read_len] = '.';
					}
					else {
						buf[read_len] = '\0';
					}
					printf("%s: %s", display_name, buf);
				}
				close(ffd);
			}
			if(event_count && --event_count == 0) return 0;
			event_size = sizeof(*event) + event->len;
			res -= event_size;
			event_pos += event_size;
		}
	}

	return 0;
}