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OvmfPkg/VirtioFsDxe: implement the wrapper function for FUSE_OPEN
[mirror_edk2.git] / OvmfPkg / VirtioFsDxe / VirtioFsDxe.inf
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1## @file\r
2# Provide EFI_SIMPLE_FILE_SYSTEM_PROTOCOL instances on virtio-fs devices.\r
3#\r
4# Copyright (C) 2020, Red Hat, Inc.\r
5#\r
6# SPDX-License-Identifier: BSD-2-Clause-Patent\r
7#\r
8#\r
9# Permission Model of this driver:\r
10#\r
11# Regardless of the UID and GID values this driver send in the FUSE request\r
12# header, the daemon (that is, the Virtio Filesystem device) always acts with\r
13# root privileges on the host side. The only time the daemon considers said UID\r
14# and GID fields is when creating a new file or directory. Thus, the guest\r
15# driver cannot rely on the host for enforcing any file mode permissions,\r
16# regardless of the "personality" that the guest driver poses as, because\r
17# "root" on the host side ignores all file mode bits.\r
18#\r
19# Therefore the guest driver has to do its own permission checking, and use the\r
20# host-side file mode bits only as a kind of "metadata storage" or "reminder"\r
21# -- hopefully in a way that makes some sense on the host side too.\r
22#\r
23# The complete mapping between the EFI_FILE_PROTOCOL and the host-side file\r
24# mode bits is described below.\r
25#\r
26# - The guest driver poses as UID 0, GID 0, PID 1.\r
27#\r
28# - If and only if all "w" bits are missing from a file on the host side, then\r
29# the file or directory is reported as EFI_FILE_READ_ONLY in the guest. When\r
30# setting EFI_FILE_READ_ONLY in the guest, all "w" bits (0222) are cleared on\r
31# the host; when clearing EFI_FILE_READ_ONLY in the guest, all "w" bits are\r
32# set on the host. Viewed from the host side, this sort of reflects that an\r
33# EFI_FILE_READ_ONLY file should not be written by anyone.\r
34#\r
35# - The attributes EFI_FILE_HIDDEN, EFI_FILE_SYSTEM, EFI_FILE_RESERVED, and\r
36# EFI_FILE_ARCHIVE are never reported in the guest, and they are silently\r
37# ignored when a SetInfo() call or a file-creating Open() call requests them.\r
38#\r
39# - On the host, files are created with 0666 file mode bits, directories are\r
40# created with 0777 file mode bits.\r
41#\r
42# - In the guest, the EFI_FILE_READ_ONLY attribute only controls the permitted\r
43# open mode. In particular, on directories, the EFI_FILE_READ_ONLY attribute\r
44# does not prevent the creation or deletion of entries inside the directory;\r
45# EFI_FILE_READ_ONLY only prevents the renaming, deleting, flushing (syncing)\r
46# and touching of the directory itself (with "touching" meaning updating the\r
47# timestamps). The fact that EFI_FILE_READ_ONLY being set on a directory is\r
48# irrelevant in the guest with regard to entry creation/deletion, is\r
49# well-mirrored by the fact that virtiofsd -- which runs as root, regardless\r
50# of guest driver personality -- ignores the absence of "w" permissions on a\r
51# host-side directory, when creating or removing entries in it.\r
52#\r
53# - When an EFI_FILE_PROTOCOL is opened read-only, then the Delete(), Write()\r
54# and Flush() member functions are disabled for it. Additionally, SetInfo()\r
55# is restricted to flipping the EFI_FILE_READ_ONLY bit (which takes effect at\r
56# the next Open()).\r
57#\r
58# - As a consequence of the above, for deleting a directory, it must be\r
59# presented in the guest as openable for writing.\r
60#\r
61# - We diverge from the UEFI spec, and permit Flush() on a directory that has\r
62# been opened read-write; otherwise the only way to invoke FUSE_FSYNCDIR on a\r
63# directory would be to Close() it.\r
64#\r
65# - OpenVolume() opens the root directory for read-only access. The Open()\r
66# member function may open it for read-write access. While the root directory\r
67# cannot be renamed or deleted, opening it for read-write access is useful\r
68# for calling Flush(), according to the previous paragraph, or for updating\r
69# the root directory's timestamps with SetInfo().\r
70##\r
71\r
72[Defines]\r
73 INF_VERSION = 1.29\r
74 BASE_NAME = VirtioFsDxe\r
75 FILE_GUID = 7BD9DDF7-8B83-488E-AEC9-24C78610289C\r
76 MODULE_TYPE = UEFI_DRIVER\r
77 ENTRY_POINT = VirtioFsEntryPoint\r
78\r
79[Packages]\r
80 MdePkg/MdePkg.dec\r
b55d6622 81 OvmfPkg/OvmfPkg.dec\r
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82\r
83[Sources]\r
84 DriverBinding.c\r
d0474399 85 FuseFlush.c\r
92a4d30e 86 FuseForget.c\r
2e151d26 87 FuseFsync.c\r
fa97e372 88 FuseInit.c\r
da82d2e3 89 FuseOpen.c\r
b62a0c56 90 FuseOpenDir.c\r
72d4f133 91 FuseRelease.c\r
eaa7115d 92 Helpers.c\r
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93 SimpleFsClose.c\r
94 SimpleFsDelete.c\r
95 SimpleFsFlush.c\r
96 SimpleFsGetInfo.c\r
97 SimpleFsGetPosition.c\r
98 SimpleFsOpen.c\r
b55d6622 99 SimpleFsOpenVolume.c\r
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100 SimpleFsRead.c\r
101 SimpleFsSetInfo.c\r
102 SimpleFsSetPosition.c\r
103 SimpleFsWrite.c\r
b55d6622 104 VirtioFsDxe.h\r
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105\r
106[LibraryClasses]\r
107 BaseLib\r
9307d7c7 108 BaseMemoryLib\r
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109 DebugLib\r
110 MemoryAllocationLib\r
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111 UefiBootServicesTableLib\r
112 UefiDriverEntryPoint\r
eaa7115d 113 VirtioLib\r
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114\r
115[Protocols]\r
116 gEfiComponentName2ProtocolGuid ## PRODUCES\r
117 gEfiDriverBindingProtocolGuid ## PRODUCES\r
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118 gEfiSimpleFileSystemProtocolGuid ## BY_START\r
119 gVirtioDeviceProtocolGuid ## TO_START\r