1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright 2021, Collabora Ltd.
4 */
5
6 #define _GNU_SOURCE
7 #include <errno.h>
8 #include <err.h>
9 #include <stdlib.h>
10 #include <stdio.h>
11 #include <fcntl.h>
12 #include <sys/fanotify.h>
13 #include <sys/types.h>
14 #include <unistd.h>
15
16 #ifndef FAN_FS_ERROR
17 #define FAN_FS_ERROR 0x00008000
18 #define FAN_EVENT_INFO_TYPE_ERROR 5
19
20 struct fanotify_event_info_error {
21 struct fanotify_event_info_header hdr;
22 __s32 error;
23 __u32 error_count;
24 };
25 #endif
26
27 #ifndef FILEID_INO32_GEN
28 #define FILEID_INO32_GEN 1
29 #endif
30
31 #ifndef FILEID_INVALID
32 #define FILEID_INVALID 0xff
33 #endif
34
35 static void print_fh(struct file_handle *fh)
36 {
37 int i;
38 uint32_t *h = (uint32_t *) fh->f_handle;
39
40 printf("\tfh: ");
41 for (i = 0; i < fh->handle_bytes; i++)
42 printf("%hhx", fh->f_handle[i]);
43 printf("\n");
44
45 printf("\tdecoded fh: ");
46 if (fh->handle_type == FILEID_INO32_GEN)
47 printf("inode=%u gen=%u\n", h[0], h[1]);
48 else if (fh->handle_type == FILEID_INVALID && !fh->handle_bytes)
49 printf("Type %d (Superblock error)\n", fh->handle_type);
50 else
51 printf("Type %d (Unknown)\n", fh->handle_type);
52
53 }
54
55 static void handle_notifications(char *buffer, int len)
56 {
57 struct fanotify_event_metadata *event =
58 (struct fanotify_event_metadata *) buffer;
59 struct fanotify_event_info_header *info;
60 struct fanotify_event_info_error *err;
61 struct fanotify_event_info_fid *fid;
62 int off;
63
64 for (; FAN_EVENT_OK(event, len); event = FAN_EVENT_NEXT(event, len)) {
65
66 if (event->mask != FAN_FS_ERROR) {
67 printf("unexpected FAN MARK: %llx\n",
68 (unsigned long long)event->mask);
69 goto next_event;
70 }
71
72 if (event->fd != FAN_NOFD) {
73 printf("Unexpected fd (!= FAN_NOFD)\n");
74 goto next_event;
75 }
76
77 printf("FAN_FS_ERROR (len=%d)\n", event->event_len);
78
79 for (off = sizeof(*event) ; off < event->event_len;
80 off += info->len) {
81 info = (struct fanotify_event_info_header *)
82 ((char *) event + off);
83
84 switch (info->info_type) {
85 case FAN_EVENT_INFO_TYPE_ERROR:
86 err = (struct fanotify_event_info_error *) info;
87
88 printf("\tGeneric Error Record: len=%d\n",
89 err->hdr.len);
90 printf("\terror: %d\n", err->error);
91 printf("\terror_count: %d\n", err->error_count);
92 break;
93
94 case FAN_EVENT_INFO_TYPE_FID:
95 fid = (struct fanotify_event_info_fid *) info;
96
97 printf("\tfsid: %x%x\n",
98 fid->fsid.val[0], fid->fsid.val[1]);
99 print_fh((struct file_handle *) &fid->handle);
100 break;
101
102 default:
103 printf("\tUnknown info type=%d len=%d:\n",
104 info->info_type, info->len);
105 }
106 }
107 next_event:
108 printf("---\n\n");
109 }
110 }
111
112 int main(int argc, char **argv)
113 {
114 int fd;
115
116 char buffer[BUFSIZ];
117
118 if (argc < 2) {
119 printf("Missing path argument\n");
120 return 1;
121 }
122
123 fd = fanotify_init(FAN_CLASS_NOTIF|FAN_REPORT_FID, O_RDONLY);
124 if (fd < 0)
125 errx(1, "fanotify_init");
126
127 if (fanotify_mark(fd, FAN_MARK_ADD|FAN_MARK_FILESYSTEM,
128 FAN_FS_ERROR, AT_FDCWD, argv[1])) {
129 errx(1, "fanotify_mark");
130 }
131
132 while (1) {
133 int n = read(fd, buffer, BUFSIZ);
134
135 if (n < 0)
136 errx(1, "read");
137
138 handle_notifications(buffer, n);
139 }
140
141 return 0;
142 }
143
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