mirror of https://github.com/acidanthera/audk.git
OvmfPkg/VirtioFsDxe: add helper for composing rename/move destination path
The EFI_FILE_PROTOCOL.SetInfo() member is somewhat under-specified; one of its modes of operation is renaming/moving the file. In order to create the destination pathname in canonical format, 2*2=4 cases have to be considered. For the sake of discussion, assume the current canonical pathname of a VIRTIO_FS_FILE is "/home/user/f1.txt". Then, consider the following rename/move requests from EFI_FILE_PROTOCOL.SetInfo(): Destination requested Destination Move into Destination in by SetInfo() relative? directory? canonical format --------------------- ----------- ---------- ----------------------- L"\\dir\\f2.txt" no no "/dir/f2.txt" L"\\dir\\" no yes "/dir/f1.txt" L"dir\\f2.txt" yes no "/home/user/dir/f2.txt" L"dir\\" yes yes "/home/user/dir/f1.txt" Add the VirtioFsComposeRenameDestination() function, for composing the last column from the current canonical pathname and the SetInfo() input. The function works on the following principles: - The prefix of the destination path is "/", if the SetInfo() rename request is absolute. Otherwise, the dest prefix is the "current directory" (the most specific parent directory) of the original pathname (in the above example, "/home/user"). - The suffix of the destination path is precisely the SetInfo() request string, if the "move into directory" convenience format -- the trailing backslash -- is not used. (In the above example, L"\\dir\\f2.txt" and L"dir\\f2.txt".) Otherwise, the suffix is the SetInfo() request, plus the original basename (in the above example, L"\\dir\\f1.txt" and L"dir\\f1.txt"). - The complete destination is created by fusing the dest prefix and the dest suffix, using the VirtioFsAppendPath() function. Cc: Ard Biesheuvel <ard.biesheuvel@arm.com> Cc: Jordan Justen <jordan.l.justen@intel.com> Cc: Philippe Mathieu-Daudé <philmd@redhat.com> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3097 Signed-off-by: Laszlo Ersek <lersek@redhat.com> Message-Id: <20201216211125.19496-43-lersek@redhat.com> Acked-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
This commit is contained in:
Laszlo Ersek
mergify[bot]
parent
bea1f51d6e
commit
c3f76ef89d
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@ -1783,6 +1783,200 @@ VirtioFsGetBasename (
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return EFI_SUCCESS;
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}
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/**
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Format the destination of a rename/move operation as a dynamically allocated
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canonical pathname.
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Any dot-dot in RhsPath16 that would remove the root directory is dropped, and
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reported through RootEscape, without failing the function call.
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@param[in] LhsPath8 The source pathname operand of the rename/move
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operation, expressed as a canonical pathname (as
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defined in the description of VirtioFsAppendPath()).
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The root directory "/" cannot be renamed/moved, and
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will be rejected.
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@param[in] RhsPath16 The destination pathname operand expressed as a
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UEFI-style CHAR16 pathname.
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If RhsPath16 starts with a backslash, then RhsPath16
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is considered absolute. Otherwise, RhsPath16 is
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interpreted relative to the most specific parent
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directory found in LhsPath8.
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Independently, if RhsPath16 ends with a backslash
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(i.e., RhsPath16 is given in the "move into
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directory" convenience form), then RhsPath16 is
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interpreted with the basename of LhsPath8 appended.
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Otherwise, the last pathname component of RhsPath16
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is taken as the last pathname component of the
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rename/move destination.
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An empty RhsPath16 is rejected.
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@param[out] ResultPath8 The POSIX-style, canonical format pathname that
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leads to the renamed/moved file. After use, the
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caller is responsible for freeing ResultPath8.
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@param[out] RootEscape Set to TRUE if at least one dot-dot component in
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RhsPath16 attempted to escape the root directory;
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set to FALSE otherwise.
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@retval EFI_SUCCESS ResultPath8 has been produced. RootEscape has
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been output.
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@retval EFI_INVALID_PARAMETER LhsPath8 is "/".
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@retval EFI_INVALID_PARAMETER RhsPath16 is zero-length.
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@retval EFI_INVALID_PARAMETER RhsPath16 failed the
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VIRTIO_FS_MAX_PATHNAME_LENGTH check.
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@retval EFI_OUT_OF_RESOURCES Memory allocation failed.
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@retval EFI_OUT_OF_RESOURCES ResultPath8 would have failed the
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VIRTIO_FS_MAX_PATHNAME_LENGTH check.
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@retval EFI_UNSUPPORTED RhsPath16 contains a character that either
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falls outside of the printable ASCII set, or
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is a forward slash.
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**/
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EFI_STATUS
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VirtioFsComposeRenameDestination (
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IN CHAR8 *LhsPath8,
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IN CHAR16 *RhsPath16,
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OUT CHAR8 **ResultPath8,
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OUT BOOLEAN *RootEscape
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)
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{
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//
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// Lengths are expressed as numbers of characters (CHAR8 or CHAR16),
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// excluding terminating NULs. Sizes are expressed as byte counts, including
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// the bytes taken up by terminating NULs.
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//
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UINTN RhsLen;
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UINTN LhsBasename16Size;
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EFI_STATUS Status;
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UINTN LhsBasenameLen;
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UINTN DestSuffix16Size;
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CHAR16 *DestSuffix16;
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CHAR8 *DestPrefix8;
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//
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// An empty destination operand for the rename/move operation is not allowed.
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//
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RhsLen = StrLen (RhsPath16);
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if (RhsLen == 0) {
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return EFI_INVALID_PARAMETER;
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}
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//
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// Enforce length restriction on RhsPath16.
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//
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if (RhsLen > VIRTIO_FS_MAX_PATHNAME_LENGTH) {
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return EFI_INVALID_PARAMETER;
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}
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//
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// Determine the length of the basename of LhsPath8.
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//
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LhsBasename16Size = 0;
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Status = VirtioFsGetBasename (LhsPath8, NULL, &LhsBasename16Size);
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ASSERT (Status == EFI_BUFFER_TOO_SMALL);
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ASSERT (LhsBasename16Size >= sizeof (CHAR16));
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ASSERT (LhsBasename16Size % sizeof (CHAR16) == 0);
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LhsBasenameLen = LhsBasename16Size / sizeof (CHAR16) - 1;
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if (LhsBasenameLen == 0) {
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//
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// The root directory cannot be renamed/moved.
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//
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return EFI_INVALID_PARAMETER;
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}
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//
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// Resolve the "move into directory" convenience form in RhsPath16.
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//
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if (RhsPath16[RhsLen - 1] == L'\\') {
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//
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// Append the basename of LhsPath8 as a CHAR16 string to RhsPath16.
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//
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DestSuffix16Size = RhsLen * sizeof (CHAR16) + LhsBasename16Size;
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DestSuffix16 = AllocatePool (DestSuffix16Size);
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if (DestSuffix16 == NULL) {
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return EFI_OUT_OF_RESOURCES;
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}
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CopyMem (DestSuffix16, RhsPath16, RhsLen * sizeof (CHAR16));
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Status = VirtioFsGetBasename (LhsPath8, DestSuffix16 + RhsLen,
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&LhsBasename16Size);
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ASSERT_EFI_ERROR (Status);
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} else {
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//
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// Just create a copy of RhsPath16.
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//
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DestSuffix16Size = (RhsLen + 1) * sizeof (CHAR16);
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DestSuffix16 = AllocateCopyPool (DestSuffix16Size, RhsPath16);
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if (DestSuffix16 == NULL) {
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return EFI_OUT_OF_RESOURCES;
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}
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}
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//
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// If the destination operand is absolute, it will be interpreted relative to
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// the root directory.
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//
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// Otherwise (i.e., if the destination operand is relative), then create the
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// canonical pathname that the destination operand is interpreted relatively
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// to; that is, the canonical pathname of the most specific parent directory
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// found in LhsPath8.
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//
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if (DestSuffix16[0] == L'\\') {
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DestPrefix8 = AllocateCopyPool (sizeof "/", "/");
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if (DestPrefix8 == NULL) {
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Status = EFI_OUT_OF_RESOURCES;
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goto FreeDestSuffix16;
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}
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} else {
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UINTN LhsLen;
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UINTN DestPrefixLen;
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//
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// Strip the basename of LhsPath8.
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//
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LhsLen = AsciiStrLen (LhsPath8);
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ASSERT (LhsBasenameLen < LhsLen);
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DestPrefixLen = LhsLen - LhsBasenameLen;
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ASSERT (LhsPath8[DestPrefixLen - 1] == '/');
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//
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// If we're not at the root directory, strip the slash too.
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//
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if (DestPrefixLen > 1) {
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DestPrefixLen--;
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}
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DestPrefix8 = AllocatePool (DestPrefixLen + 1);
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if (DestPrefix8 == NULL) {
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Status = EFI_OUT_OF_RESOURCES;
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goto FreeDestSuffix16;
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}
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CopyMem (DestPrefix8, LhsPath8, DestPrefixLen);
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DestPrefix8[DestPrefixLen] = '\0';
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}
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//
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// Now combine DestPrefix8 and DestSuffix16 into the final canonical
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// pathname.
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//
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Status = VirtioFsAppendPath (DestPrefix8, DestSuffix16, ResultPath8,
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RootEscape);
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FreePool (DestPrefix8);
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//
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// Fall through.
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//
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FreeDestSuffix16:
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FreePool (DestSuffix16);
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return Status;
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}
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/**
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Convert select fields of a VIRTIO_FS_FUSE_ATTRIBUTES_RESPONSE object to
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corresponding fields in EFI_FILE_INFO.
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@ -262,6 +262,14 @@ VirtioFsGetBasename (
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IN OUT UINTN *BasenameSize
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);
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EFI_STATUS
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VirtioFsComposeRenameDestination (
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IN CHAR8 *LhsPath8,
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IN CHAR16 *RhsPath16,
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OUT CHAR8 **ResultPath8,
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OUT BOOLEAN *RootEscape
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);
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EFI_STATUS
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VirtioFsFuseAttrToEfiFileInfo (
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IN VIRTIO_FS_FUSE_ATTRIBUTES_RESPONSE *FuseAttr,
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