linuxdebug/samples/fanotify/fs-monitor.c

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2024-07-16 15:50:57 +02:00
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright 2021, Collabora Ltd.
*/
#define _GNU_SOURCE
#include <errno.h>
#include <err.h>
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <sys/fanotify.h>
#include <sys/types.h>
#include <unistd.h>
#ifndef FAN_FS_ERROR
#define FAN_FS_ERROR 0x00008000
#define FAN_EVENT_INFO_TYPE_ERROR 5
struct fanotify_event_info_error {
struct fanotify_event_info_header hdr;
__s32 error;
__u32 error_count;
};
#endif
#ifndef FILEID_INO32_GEN
#define FILEID_INO32_GEN 1
#endif
#ifndef FILEID_INVALID
#define FILEID_INVALID 0xff
#endif
static void print_fh(struct file_handle *fh)
{
int i;
uint32_t *h = (uint32_t *) fh->f_handle;
printf("\tfh: ");
for (i = 0; i < fh->handle_bytes; i++)
printf("%hhx", fh->f_handle[i]);
printf("\n");
printf("\tdecoded fh: ");
if (fh->handle_type == FILEID_INO32_GEN)
printf("inode=%u gen=%u\n", h[0], h[1]);
else if (fh->handle_type == FILEID_INVALID && !fh->handle_bytes)
printf("Type %d (Superblock error)\n", fh->handle_type);
else
printf("Type %d (Unknown)\n", fh->handle_type);
}
static void handle_notifications(char *buffer, int len)
{
struct fanotify_event_metadata *event =
(struct fanotify_event_metadata *) buffer;
struct fanotify_event_info_header *info;
struct fanotify_event_info_error *err;
struct fanotify_event_info_fid *fid;
int off;
for (; FAN_EVENT_OK(event, len); event = FAN_EVENT_NEXT(event, len)) {
if (event->mask != FAN_FS_ERROR) {
printf("unexpected FAN MARK: %llx\n",
(unsigned long long)event->mask);
goto next_event;
}
if (event->fd != FAN_NOFD) {
printf("Unexpected fd (!= FAN_NOFD)\n");
goto next_event;
}
printf("FAN_FS_ERROR (len=%d)\n", event->event_len);
for (off = sizeof(*event) ; off < event->event_len;
off += info->len) {
info = (struct fanotify_event_info_header *)
((char *) event + off);
switch (info->info_type) {
case FAN_EVENT_INFO_TYPE_ERROR:
err = (struct fanotify_event_info_error *) info;
printf("\tGeneric Error Record: len=%d\n",
err->hdr.len);
printf("\terror: %d\n", err->error);
printf("\terror_count: %d\n", err->error_count);
break;
case FAN_EVENT_INFO_TYPE_FID:
fid = (struct fanotify_event_info_fid *) info;
printf("\tfsid: %x%x\n",
fid->fsid.val[0], fid->fsid.val[1]);
print_fh((struct file_handle *) &fid->handle);
break;
default:
printf("\tUnknown info type=%d len=%d:\n",
info->info_type, info->len);
}
}
next_event:
printf("---\n\n");
}
}
int main(int argc, char **argv)
{
int fd;
char buffer[BUFSIZ];
if (argc < 2) {
printf("Missing path argument\n");
return 1;
}
fd = fanotify_init(FAN_CLASS_NOTIF|FAN_REPORT_FID, O_RDONLY);
if (fd < 0)
errx(1, "fanotify_init");
if (fanotify_mark(fd, FAN_MARK_ADD|FAN_MARK_FILESYSTEM,
FAN_FS_ERROR, AT_FDCWD, argv[1])) {
errx(1, "fanotify_mark");
}
while (1) {
int n = read(fd, buffer, BUFSIZ);
if (n < 0)
errx(1, "read");
handle_notifications(buffer, n);
}
return 0;
}