cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

fs-monitor.c (3082B)

      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
     20struct 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
     35static 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
     55static 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		}
    107next_event:
    108		printf("---\n\n");
    109	}
    110}
    111
    112int 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}