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, arg->show_string_prefix);
43}