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OvmfPkg/VirtioFsDxe: add helper for determining access time updates 

Add the VirtioFsGetFuseTimeUpdates() function, for determining whether an
EFI_FILE_PROTOCOL.SetInfo() invocation requests access time updates.

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: <20201216211125.19496-47-lersek@redhat.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
[lersek@redhat.com: suppress bogus VS2019 warning about lack of
 initialization for ZeroTime]
This commit is contained in:
Laszlo Ersek 2020-12-16 22:11:23 +01:00 committed by mergify[bot]
parent 6c33d7b2b1
commit 3cbd54b92f
2 changed files with 116 additions and 0 deletions
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106
OvmfPkg/VirtioFsDxe/Helpers.c
View File

@ -2213,3 +2213,109 @@ VirtioFsGetFuseSizeUpdate (
*Update = TRUE;
*Size = NewInfo->FileSize;
}
/**
Given an EFI_FILE_INFO object received in an EFI_FILE_PROTOCOL.SetInfo()
call, determine whether updating the last access time and/or the last
modification time of the file is necessary, relative to an EFI_FILE_INFO
object describing the current state of the file.
@param[in] Info The EFI_FILE_INFO describing the current state of
the file. The caller is responsible for populating
Info on input with VirtioFsFuseAttrToEfiFileInfo(),
from the current FUSE attributes of the file. The
Info->Size and Info->FileName members are ignored.
@param[in] NewInfo The EFI_FILE_INFO object received in the
EFI_FILE_PROTOCOL.SetInfo() call.
@param[out] UpdateAtime Set to TRUE on output if the last access time needs
to be updated. Set to FALSE otherwise.
@param[out] UpdateMtime Set to TRUE on output if the last modification time
needs to be updated. Set to FALSE otherwise.
@param[out] Atime If UpdateAtime is set to TRUE, then Atime provides
the last access timestamp to set (as seconds since
the Epoch). Otherwise, Atime is not written to.
@param[out] Mtime If UpdateMtime is set to TRUE, then Mtime provides
the last modification timestamp to set (as seconds
since the Epoch). Otherwise, Mtime is not written
to.
@retval EFI_SUCCESS Output parameters have been set successfully.
@retval EFI_ACCESS_DENIED NewInfo requests changing both CreateTime and
ModificationTime, but to values that differ from
each other. The Virtio Filesystem device does not
support this.
**/
EFI_STATUS
VirtioFsGetFuseTimeUpdates (
IN EFI_FILE_INFO *Info,
IN EFI_FILE_INFO *NewInfo,
OUT BOOLEAN *UpdateAtime,
OUT BOOLEAN *UpdateMtime,
OUT UINT64 *Atime,
OUT UINT64 *Mtime
)
{
EFI_TIME *Time[3];
EFI_TIME *NewTime[ARRAY_SIZE (Time)];
UINTN Idx;
STATIC CONST EFI_TIME ZeroTime = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
BOOLEAN Change[ARRAY_SIZE (Time)];
UINT64 Seconds[ARRAY_SIZE (Time)];
Time[0] = &Info->CreateTime;
Time[1] = &Info->LastAccessTime;
Time[2] = &Info->ModificationTime;
NewTime[0] = &NewInfo->CreateTime;
NewTime[1] = &NewInfo->LastAccessTime;
NewTime[2] = &NewInfo->ModificationTime;
//
// Determine which timestamps differ from the current state. (A zero time
// means "don't update", per UEFI spec.) For each timestamp that's being
// changed, calculate the seconds since the Epoch.
//
for (Idx = 0; Idx < ARRAY_SIZE (Time); Idx++) {
if (CompareMem (NewTime[Idx], &ZeroTime, sizeof (EFI_TIME)) == 0 ||
CompareMem (NewTime[Idx], Time[Idx], sizeof (EFI_TIME)) == 0) {
Change[Idx] = FALSE;
} else {
Change[Idx] = TRUE;
Seconds[Idx] = EfiTimeToEpoch (NewTime[Idx]);
}
}
//
// If a change is requested for exactly one of CreateTime and
// ModificationTime, we'll change the last modification time. If changes are
// requested for both, and to the same timestamp, we'll similarly update the
// last modification time. If changes are requested for both, but to
// different timestamps, we reject the request.
//
if (Change[0] && Change[2] && Seconds[0] != Seconds[2]) {
return EFI_ACCESS_DENIED;
}
*UpdateAtime = FALSE;
*UpdateMtime = FALSE;
if (Change[0]) {
*UpdateMtime = TRUE;
*Mtime = Seconds[0];
}
if (Change[1]) {
*UpdateAtime = TRUE;
*Atime = Seconds[1];
}
if (Change[2]) {
*UpdateMtime = TRUE;
*Mtime = Seconds[2];
}
return EFI_SUCCESS;
}

10
OvmfPkg/VirtioFsDxe/VirtioFsDxe.h
View File

@ -290,6 +290,16 @@ VirtioFsGetFuseSizeUpdate (
OUT UINT64 *Size
);
EFI_STATUS
VirtioFsGetFuseTimeUpdates (
IN EFI_FILE_INFO *Info,
IN EFI_FILE_INFO *NewInfo,
OUT BOOLEAN *UpdateAtime,
OUT BOOLEAN *UpdateMtime,
OUT UINT64 *Atime,
OUT UINT64 *Mtime
);
//
// Wrapper functions for FUSE commands (primitives).
//