1// SPDX-License-Identifier: LGPL-2.1
2/*
3 * trace/beauty/mount_flags.c
4 *
5 * Copyright (C) 2018, Red Hat Inc, Arnaldo Carvalho de Melo <acme@redhat.com>
6 */
7
8#include "trace/beauty/beauty.h"
9#include <linux/compiler.h>
10#include <linux/kernel.h>
11#include <linux/log2.h>
12#include <sys/mount.h>
13
14static size_t mount__scnprintf_flags(unsigned long flags, char *bf, size_t size, bool show_prefix)
15{
16#include "trace/beauty/generated/mount_flags_array.c"
17 static DEFINE_STRARRAY(mount_flags, "MS_");
18
19 return strarray__scnprintf_flags(&strarray__mount_flags, bf, size, show_prefix, flags);
20}
21
22unsigned long syscall_arg__mask_val_mount_flags(struct syscall_arg *arg __maybe_unused, unsigned long flags)
23{
24 // do_mount in fs/namespace.c:
25 /*
26 * Pre-0.97 versions of mount() didn't have a flags word. When the
27 * flags word was introduced its top half was required to have the
28 * magic value 0xC0ED, and this remained so until 2.4.0-test9.
29 * Therefore, if this magic number is present, it carries no
30 * information and must be discarded.
31 */
32 if ((flags & MS_MGC_MSK) == MS_MGC_VAL)
33 flags &= ~MS_MGC_MSK;
34
35 return flags;
36}
37
38size_t syscall_arg__scnprintf_mount_flags(char *bf, size_t size, struct syscall_arg *arg)
39{
40 unsigned long flags = arg->val;
41
42 return mount__scnprintf_flags(flags, bf, size, show_prefix: arg->show_string_prefix);
43}
44

source code of linux/tools/perf/trace/beauty/mount_flags.c