1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
|
/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <Kernel/FileSystem/Custody.h>
#include <Kernel/FileSystem/DevPtsFS.h>
#include <Kernel/FileSystem/Ext2FileSystem.h>
#include <Kernel/FileSystem/FATFS/FileSystem.h>
#include <Kernel/FileSystem/ISO9660FileSystem.h>
#include <Kernel/FileSystem/Plan9FileSystem.h>
#include <Kernel/FileSystem/ProcFS.h>
#include <Kernel/FileSystem/SysFS/FileSystem.h>
#include <Kernel/FileSystem/TmpFS/FileSystem.h>
#include <Kernel/FileSystem/VirtualFileSystem.h>
#include <Kernel/Process.h>
namespace Kernel {
struct FileSystemInitializer {
StringView short_name;
StringView name;
bool requires_open_file_description { false };
bool requires_block_device { false };
bool requires_seekable_file { false };
ErrorOr<NonnullLockRefPtr<FileSystem>> (*create_with_fd)(OpenFileDescription&) = nullptr;
ErrorOr<NonnullLockRefPtr<FileSystem>> (*create)(void) = nullptr;
};
static constexpr FileSystemInitializer s_initializers[] = {
{ "proc"sv, "ProcFS"sv, false, false, false, {}, ProcFS::try_create },
{ "devpts"sv, "DevPtsFS"sv, false, false, false, {}, DevPtsFS::try_create },
{ "sys"sv, "SysFS"sv, false, false, false, {}, SysFS::try_create },
{ "tmp"sv, "TmpFS"sv, false, false, false, {}, TmpFS::try_create },
{ "ext2"sv, "Ext2FS"sv, true, true, true, Ext2FS::try_create, {} },
{ "9p"sv, "Plan9FS"sv, true, true, true, Plan9FS::try_create, {} },
{ "iso9660"sv, "ISO9660FS"sv, true, true, true, ISO9660FS::try_create, {} },
{ "fat"sv, "FATFS"sv, true, true, true, FATFS::try_create, {} },
};
static ErrorOr<NonnullLockRefPtr<FileSystem>> find_or_create_filesystem_instance(StringView fs_type, OpenFileDescription* possible_description)
{
for (auto& initializer_entry : s_initializers) {
if (fs_type != initializer_entry.short_name && fs_type != initializer_entry.name)
continue;
if (!initializer_entry.requires_open_file_description) {
VERIFY(initializer_entry.create);
NonnullLockRefPtr<FileSystem> fs = TRY(initializer_entry.create());
return fs;
}
// Note: If there's an associated file description with the filesystem, we could
// try to first find it from the VirtualFileSystem filesystem list and if it was not found,
// then create it and add it.
VERIFY(initializer_entry.create_with_fd);
if (!possible_description)
return EBADF;
OpenFileDescription& description = *possible_description;
if (initializer_entry.requires_block_device && !description.file().is_block_device())
return ENOTBLK;
if (initializer_entry.requires_seekable_file && !description.file().is_seekable()) {
dbgln("mount: this is not a seekable file");
return ENODEV;
}
return TRY(VirtualFileSystem::the().find_already_existing_or_create_file_backed_file_system(description, initializer_entry.create_with_fd));
}
return ENODEV;
}
ErrorOr<FlatPtr> Process::sys$mount(Userspace<Syscall::SC_mount_params const*> user_params)
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this);
TRY(require_no_promises());
auto credentials = this->credentials();
if (!credentials->is_superuser())
return EPERM;
auto params = TRY(copy_typed_from_user(user_params));
auto source_fd = params.source_fd;
auto target = TRY(try_copy_kstring_from_user(params.target));
auto fs_type_string = TRY(try_copy_kstring_from_user(params.fs_type));
auto fs_type = fs_type_string->view();
auto description_or_error = open_file_description(source_fd);
if (!description_or_error.is_error())
dbgln("mount {}: source fd {} @ {}", fs_type, source_fd, target);
else
dbgln("mount {} @ {}", fs_type, target);
auto target_custody = TRY(VirtualFileSystem::the().resolve_path(credentials, target->view(), current_directory()));
if (params.flags & MS_REMOUNT) {
// We're not creating a new mount, we're updating an existing one!
TRY(VirtualFileSystem::the().remount(target_custody, params.flags & ~MS_REMOUNT));
return 0;
}
if (params.flags & MS_BIND) {
// We're doing a bind mount.
if (description_or_error.is_error())
return description_or_error.release_error();
auto description = description_or_error.release_value();
if (!description->custody()) {
// We only support bind-mounting inodes, not arbitrary files.
return ENODEV;
}
TRY(VirtualFileSystem::the().bind_mount(*description->custody(), target_custody, params.flags));
return 0;
}
LockRefPtr<FileSystem> fs;
if (!description_or_error.is_error()) {
auto description = description_or_error.release_value();
fs = TRY(find_or_create_filesystem_instance(fs_type, description.ptr()));
auto source_pseudo_path = TRY(description->pseudo_path());
dbgln("mount: attempting to mount {} on {}", source_pseudo_path, target);
} else {
fs = TRY(find_or_create_filesystem_instance(fs_type, {}));
}
TRY(fs->initialize());
TRY(VirtualFileSystem::the().mount(*fs, target_custody, params.flags));
return 0;
}
ErrorOr<FlatPtr> Process::sys$umount(Userspace<char const*> user_mountpoint, size_t mountpoint_length)
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this);
auto credentials = this->credentials();
if (!credentials->is_superuser())
return EPERM;
TRY(require_no_promises());
auto mountpoint = TRY(get_syscall_path_argument(user_mountpoint, mountpoint_length));
auto custody = TRY(VirtualFileSystem::the().resolve_path(credentials, mountpoint->view(), current_directory()));
TRY(VirtualFileSystem::the().unmount(*custody));
return 0;
}
}
|
