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 
14 static 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 
22 unsigned 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 
38 size_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 }
44