[edk2-devel] [edk2 PATCH 32/48] OvmfPkg/VirtioFsDxe: add a shared wrapper for FUSE_READ / FUSE_READDIRPLUS
Laszlo Ersek
lersek at redhat.com
Wed Dec 16 21:11:09 UTC 2020
Add the VirtioFsFuseReadFileOrDir() function, for sending the FUSE_READ or
FUSE_READDIRPLUS command to the Virtio Filesystem device.
Parsing the structured FUSE_READDIRPLUS output is complex, and cannot be
integrated into the wrapper function. Given that fact, FUSE_READ and
FUSE_READDIRPLUS turn out to need identical low-level handling, except for
the opcode. Hence the shared wrapper function.
(It's prudent to verify whether the FUSE server supports FUSE_READDIRPLUS,
so update the session init code accordingly.)
This is the first FUSE request wrapper function that deals with a variable
size tail buffer.
Cc: Ard Biesheuvel <ard.biesheuvel at arm.com>
Cc: Jordan Justen <jordan.l.justen at intel.com>
Cc: Philippe Mathieu-Daudé <philmd at redhat.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3097
Signed-off-by: Laszlo Ersek <lersek at redhat.com>
---
OvmfPkg/Include/IndustryStandard/VirtioFs.h | 67 +++++++
OvmfPkg/VirtioFsDxe/VirtioFsDxe.inf | 1 +
OvmfPkg/VirtioFsDxe/VirtioFsDxe.h | 11 ++
OvmfPkg/VirtioFsDxe/FuseInit.c | 10 +-
OvmfPkg/VirtioFsDxe/FuseRead.c | 191 ++++++++++++++++++++
5 files changed, 276 insertions(+), 4 deletions(-)
diff --git a/OvmfPkg/Include/IndustryStandard/VirtioFs.h b/OvmfPkg/Include/IndustryStandard/VirtioFs.h
index 800d3651e12b..fa8c40019f4e 100644
--- a/OvmfPkg/Include/IndustryStandard/VirtioFs.h
+++ b/OvmfPkg/Include/IndustryStandard/VirtioFs.h
@@ -103,36 +103,71 @@ typedef struct {
#define VIRTIO_FS_FUSE_MODE_PERM_WOTH 0000002u
//
// Flags for VirtioFsFuseOpOpen.
//
#define VIRTIO_FS_FUSE_OPEN_REQ_F_RDONLY 0
#define VIRTIO_FS_FUSE_OPEN_REQ_F_RDWR 2
+//
+// Flags for VirtioFsFuseOpInit.
+//
+#define VIRTIO_FS_FUSE_INIT_REQ_F_DO_READDIRPLUS BIT13
+
+/**
+ Macro for calculating the size of a directory stream entry.
+
+ The macro may evaluate Namelen multiple times.
+
+ The macro evaluates to a UINTN value that is safe to cast to UINT32.
+
+ @param[in] Namelen The size of the filename byte array that follows
+ VIRTIO_FS_FUSE_DIRENTPLUS_RESPONSE in the directory
+ stream, as reported by
+ VIRTIO_FS_FUSE_STATFS_RESPONSE.Namelen or
+ VIRTIO_FS_FUSE_DIRENTPLUS_RESPONSE.Namelen. The filename
+ byte array is not NUL-terminated.
+
+ @retval 0 Namelen was zero or greater than SIZE_4KB.
+
+ @return The number of bytes in the directory entry, including the
+ VIRTIO_FS_FUSE_DIRENTPLUS_RESPONSE header.
+**/
+#define VIRTIO_FS_FUSE_DIRENTPLUS_RESPONSE_SIZE(Namelen) \
+ ((Namelen) == 0 || (Namelen) > SIZE_4KB ? \
+ (UINTN)0 : \
+ ALIGN_VALUE ( \
+ sizeof (VIRTIO_FS_FUSE_DIRENTPLUS_RESPONSE) + (UINTN)(Namelen), \
+ sizeof (UINT64) \
+ ) \
+ )
+
//
// FUSE operation codes.
//
typedef enum {
VirtioFsFuseOpLookup = 1,
VirtioFsFuseOpForget = 2,
VirtioFsFuseOpGetAttr = 3,
VirtioFsFuseOpMkDir = 9,
VirtioFsFuseOpUnlink = 10,
VirtioFsFuseOpRmDir = 11,
VirtioFsFuseOpOpen = 14,
+ VirtioFsFuseOpRead = 15,
VirtioFsFuseOpStatFs = 17,
VirtioFsFuseOpRelease = 18,
VirtioFsFuseOpFsync = 20,
VirtioFsFuseOpFlush = 25,
VirtioFsFuseOpInit = 26,
VirtioFsFuseOpOpenDir = 27,
VirtioFsFuseOpReleaseDir = 29,
VirtioFsFuseOpFsyncDir = 30,
VirtioFsFuseOpCreate = 35,
+ VirtioFsFuseOpReadDirPlus = 44,
} VIRTIO_FS_FUSE_OPCODE;
#pragma pack (1)
//
// Request-response headers common to all request types.
//
typedef struct {
UINT32 Len;
@@ -229,16 +264,29 @@ typedef struct {
} VIRTIO_FS_FUSE_OPEN_REQUEST;
typedef struct {
UINT64 FileHandle;
UINT32 OpenFlags;
UINT32 Padding;
} VIRTIO_FS_FUSE_OPEN_RESPONSE;
+//
+// Header for VirtioFsFuseOpRead and VirtioFsFuseOpReadDirPlus.
+//
+typedef struct {
+ UINT64 FileHandle;
+ UINT64 Offset;
+ UINT32 Size;
+ UINT32 ReadFlags;
+ UINT64 LockOwner;
+ UINT32 Flags;
+ UINT32 Padding;
+} VIRTIO_FS_FUSE_READ_REQUEST;
+
//
// Header for VirtioFsFuseOpStatFs.
//
typedef struct {
UINT64 Blocks;
UINT64 Bfree;
UINT64 Bavail;
UINT64 Files;
@@ -307,11 +355,30 @@ typedef struct {
// Header for VirtioFsFuseOpCreate.
//
typedef struct {
UINT32 Flags;
UINT32 Mode;
UINT32 Umask;
UINT32 Padding;
} VIRTIO_FS_FUSE_CREATE_REQUEST;
+
+//
+// Header for VirtioFsFuseOpReadDirPlus.
+//
+// Diverging from the rest of the headers, this structure embeds other
+// structures. The reason is that a scatter list cannot be used to receive
+// NodeResp and AttrResp separately; the record below is followed by a variable
+// size filename byte array, and then such pairs are repeated a number of
+// times. Thus, later header start offsets depend on earlier filename array
+// sizes.
+//
+typedef struct {
+ VIRTIO_FS_FUSE_NODE_RESPONSE NodeResp;
+ VIRTIO_FS_FUSE_ATTRIBUTES_RESPONSE AttrResp;
+ UINT64 NodeId;
+ UINT64 CookieForNextEntry;
+ UINT32 Namelen;
+ UINT32 Type;
+} VIRTIO_FS_FUSE_DIRENTPLUS_RESPONSE;
#pragma pack ()
#endif // VIRTIO_FS_H_
diff --git a/OvmfPkg/VirtioFsDxe/VirtioFsDxe.inf b/OvmfPkg/VirtioFsDxe/VirtioFsDxe.inf
index 3cb5c101c3a6..39c77c7c4ee9 100644
--- a/OvmfPkg/VirtioFsDxe/VirtioFsDxe.inf
+++ b/OvmfPkg/VirtioFsDxe/VirtioFsDxe.inf
@@ -88,16 +88,17 @@ [Sources]
FuseFsync.c
FuseGetAttr.c
FuseInit.c
FuseLookup.c
FuseMkDir.c
FuseOpen.c
FuseOpenDir.c
FuseOpenOrCreate.c
+ FuseRead.c
FuseRelease.c
FuseStatFs.c
FuseUnlink.c
Helpers.c
SimpleFsClose.c
SimpleFsDelete.c
SimpleFsFlush.c
SimpleFsGetInfo.c
diff --git a/OvmfPkg/VirtioFsDxe/VirtioFsDxe.h b/OvmfPkg/VirtioFsDxe/VirtioFsDxe.h
index 948fcfb6b6f3..f5501af7d0a4 100644
--- a/OvmfPkg/VirtioFsDxe/VirtioFsDxe.h
+++ b/OvmfPkg/VirtioFsDxe/VirtioFsDxe.h
@@ -293,16 +293,27 @@ VirtioFsFuseRemoveFileOrDir (
EFI_STATUS
VirtioFsFuseOpen (
IN OUT VIRTIO_FS *VirtioFs,
IN UINT64 NodeId,
IN BOOLEAN ReadWrite,
OUT UINT64 *FuseHandle
);
+EFI_STATUS
+VirtioFsFuseReadFileOrDir (
+ IN OUT VIRTIO_FS *VirtioFs,
+ IN UINT64 NodeId,
+ IN UINT64 FuseHandle,
+ IN BOOLEAN IsDir,
+ IN UINT64 Offset,
+ IN OUT UINT32 *Size,
+ OUT VOID *Data
+ );
+
EFI_STATUS
VirtioFsFuseStatFs (
IN OUT VIRTIO_FS *VirtioFs,
IN UINT64 NodeId,
OUT VIRTIO_FS_FUSE_STATFS_RESPONSE *FilesysAttr
);
EFI_STATUS
diff --git a/OvmfPkg/VirtioFsDxe/FuseInit.c b/OvmfPkg/VirtioFsDxe/FuseInit.c
index aa19dbdc05cb..7aa6ee75caf6 100644
--- a/OvmfPkg/VirtioFsDxe/FuseInit.c
+++ b/OvmfPkg/VirtioFsDxe/FuseInit.c
@@ -21,17 +21,18 @@
before VirtioFsUninit() is called.
@param[in,out] VirtioFs The Virtio Filesystem device to send the FUSE_INIT
request to. The FUSE request counter
"VirtioFs->RequestId" is set to 1 on output.
@retval EFI_SUCCESS The FUSE session has been started.
- @retval EFI_UNSUPPORTED FUSE interface version negotiation failed.
+ @retval EFI_UNSUPPORTED FUSE interface version or feature negotiation
+ failed.
@return The "errno" value mapped to an EFI_STATUS code, if
the Virtio Filesystem device explicitly reported an
error.
@return Error codes propagated from
VirtioFsSgListsValidate(), VirtioFsFuseNewRequest(),
VirtioFsSgListsSubmit(),
@@ -92,17 +93,17 @@ VirtioFsFuseInitSession (
}
//
// Populate the FUSE_INIT-specific fields.
//
InitReq.Major = VIRTIO_FS_FUSE_MAJOR;
InitReq.Minor = VIRTIO_FS_FUSE_MINOR;
InitReq.MaxReadahead = 0;
- InitReq.Flags = 0;
+ InitReq.Flags = VIRTIO_FS_FUSE_INIT_REQ_F_DO_READDIRPLUS;
//
// Submit the request.
//
Status = VirtioFsSgListsSubmit (VirtioFs, &ReqSgList, &RespSgList);
if (EFI_ERROR (Status)) {
return Status;
}
@@ -116,17 +117,18 @@ VirtioFsFuseInitSession (
DEBUG ((DEBUG_ERROR, "%a: Label=\"%s\" Errno=%d\n", __FUNCTION__,
VirtioFs->Label, CommonResp.Error));
Status = VirtioFsErrnoToEfiStatus (CommonResp.Error);
}
return Status;
}
//
- // Check FUSE interface version compatibility.
+ // Check FUSE interface version / feature compatibility.
//
if (InitResp.Major < InitReq.Major ||
- (InitResp.Major == InitReq.Major && InitResp.Minor < InitReq.Minor)) {
+ (InitResp.Major == InitReq.Major && InitResp.Minor < InitReq.Minor) ||
+ (InitResp.Flags & VIRTIO_FS_FUSE_INIT_REQ_F_DO_READDIRPLUS) == 0) {
return EFI_UNSUPPORTED;
}
return EFI_SUCCESS;
}
diff --git a/OvmfPkg/VirtioFsDxe/FuseRead.c b/OvmfPkg/VirtioFsDxe/FuseRead.c
new file mode 100644
index 000000000000..1611e298b90d
--- /dev/null
+++ b/OvmfPkg/VirtioFsDxe/FuseRead.c
@@ -0,0 +1,191 @@
+/** @file
+ FUSE_READ / FUSE_READDIRPLUS wrapper for the Virtio Filesystem device.
+
+ Copyright (C) 2020, Red Hat, Inc.
+
+ SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#include "VirtioFsDxe.h"
+
+/**
+ Read a chunk from a regular file or a directory stream, by sending the
+ FUSE_READ / FUSE_READDIRPLUS request to the Virtio Filesystem device.
+
+ The function may only be called after VirtioFsFuseInitSession() returns
+ successfully and before VirtioFsUninit() is called.
+
+ @param[in,out] VirtioFs The Virtio Filesystem device to send the FUSE_READ
+ or FUSE_READDIRPLUS request to. On output, the FUSE
+ request counter "VirtioFs->RequestId" will have been
+ incremented.
+
+ @param[in] NodeId The inode number of the regular file or directory
+ stream to read from.
+
+ @param[in] FuseHandle The open handle to the regular file or directory
+ stream to read from.
+
+ @param[in] IsDir TRUE if NodeId and FuseHandle refer to a directory,
+ FALSE if NodeId and FuseHandle refer to a regular
+ file.
+
+ @param[in] Offset If IsDir is FALSE: the absolute file position at
+ which to start reading.
+
+ If IsDir is TRUE: the directory stream cookie at
+ which to start or continue reading. The zero-valued
+ cookie identifies the start of the directory stream.
+ Further positions in the directory stream can be
+ passed in from the CookieForNextEntry field of
+ VIRTIO_FS_FUSE_DIRENTPLUS_RESPONSE.
+
+ @param[in,out] Size On input, the number of bytes to read. On successful
+ return, the number of bytes actually read, which may
+ be smaller than the value on input.
+
+ When reading a regular file (i.e., when IsDir is
+ FALSE), EOF can be detected by passing in a nonzero
+ Size, and finding a zero Size on output.
+
+ When reading a directory stream (i.e., when IsDir is
+ TRUE), Data consists of a sequence of variably-sized
+ records (directory entries). A read operation
+ returns the maximal sequence of records that fits in
+ Size, without having to truncate a record. In order
+ to guarantee progress, call
+
+ VirtioFsFuseStatFs (VirtioFs, NodeId,
+ &FilesysAttr)
+
+ first, to learn the maximum Namelen for the
+ directory stream. Then assign Size at least
+
+ VIRTIO_FS_FUSE_DIRENTPLUS_RESPONSE_SIZE (
+ FilesysAttr.Namelen)
+
+ on input. (Remember that
+ VIRTIO_FS_FUSE_DIRENTPLUS_RESPONSE_SIZE() may return
+ 0 if its Namelen argument is invalid.) EOF can be
+ detected if Size is set on input like described
+ above, and Size is zero on output.
+
+ @param[out] Data Buffer to read the bytes from the regular file or
+ the directory stream into. The caller is responsible
+ for providing room for (at least) as many bytes in
+ Data as Size is on input.
+
+ @retval EFI_SUCCESS Read successful. The caller is responsible for checking
+ Size to learn the actual byte count transferred.
+
+ @return The "errno" value mapped to an EFI_STATUS code, if the
+ Virtio Filesystem device explicitly reported an error.
+
+ @return Error codes propagated from VirtioFsSgListsValidate(),
+ VirtioFsFuseNewRequest(), VirtioFsSgListsSubmit(),
+ VirtioFsFuseCheckResponse().
+**/
+EFI_STATUS
+VirtioFsFuseReadFileOrDir (
+ IN OUT VIRTIO_FS *VirtioFs,
+ IN UINT64 NodeId,
+ IN UINT64 FuseHandle,
+ IN BOOLEAN IsDir,
+ IN UINT64 Offset,
+ IN OUT UINT32 *Size,
+ OUT VOID *Data
+ )
+{
+ VIRTIO_FS_FUSE_REQUEST CommonReq;
+ VIRTIO_FS_FUSE_READ_REQUEST ReadReq;
+ VIRTIO_FS_IO_VECTOR ReqIoVec[2];
+ VIRTIO_FS_SCATTER_GATHER_LIST ReqSgList;
+ VIRTIO_FS_FUSE_RESPONSE CommonResp;
+ VIRTIO_FS_IO_VECTOR RespIoVec[2];
+ VIRTIO_FS_SCATTER_GATHER_LIST RespSgList;
+ EFI_STATUS Status;
+ UINTN TailBufferFill;
+
+ //
+ // Set up the scatter-gather lists.
+ //
+ ReqIoVec[0].Buffer = &CommonReq;
+ ReqIoVec[0].Size = sizeof CommonReq;
+ ReqIoVec[1].Buffer = &ReadReq;
+ ReqIoVec[1].Size = sizeof ReadReq;
+ ReqSgList.IoVec = ReqIoVec;
+ ReqSgList.NumVec = ARRAY_SIZE (ReqIoVec);
+
+ RespIoVec[0].Buffer = &CommonResp;
+ RespIoVec[0].Size = sizeof CommonResp;
+ RespIoVec[1].Buffer = Data;
+ RespIoVec[1].Size = *Size;
+ RespSgList.IoVec = RespIoVec;
+ RespSgList.NumVec = ARRAY_SIZE (RespIoVec);
+
+ //
+ // Validate the scatter-gather lists; calculate the total transfer sizes.
+ //
+ Status = VirtioFsSgListsValidate (VirtioFs, &ReqSgList, &RespSgList);
+ if (EFI_ERROR (Status)) {
+ return Status;
+ }
+
+ //
+ // Populate the common request header.
+ //
+ Status = VirtioFsFuseNewRequest (
+ VirtioFs,
+ &CommonReq,
+ ReqSgList.TotalSize,
+ IsDir ? VirtioFsFuseOpReadDirPlus : VirtioFsFuseOpRead,
+ NodeId
+ );
+ if (EFI_ERROR (Status)) {
+ return Status;
+ }
+
+ //
+ // Populate the FUSE_READ- / FUSE_READDIRPLUS-specific fields.
+ //
+ ReadReq.FileHandle = FuseHandle;
+ ReadReq.Offset = Offset;
+ ReadReq.Size = *Size;
+ ReadReq.ReadFlags = 0;
+ ReadReq.LockOwner = 0;
+ ReadReq.Flags = 0;
+ ReadReq.Padding = 0;
+
+ //
+ // Submit the request.
+ //
+ Status = VirtioFsSgListsSubmit (VirtioFs, &ReqSgList, &RespSgList);
+ if (EFI_ERROR (Status)) {
+ return Status;
+ }
+
+ //
+ // Verify the response. Note that TailBufferFill is variable.
+ //
+ Status = VirtioFsFuseCheckResponse (&RespSgList, CommonReq.Unique,
+ &TailBufferFill);
+ if (EFI_ERROR (Status)) {
+ if (Status == EFI_DEVICE_ERROR) {
+ DEBUG ((DEBUG_ERROR, "%a: Label=\"%s\" NodeId=%Lu FuseHandle=%Lu "
+ "IsDir=%d Offset=0x%Lx Size=0x%x Data@%p Errno=%d\n", __FUNCTION__,
+ VirtioFs->Label, NodeId, FuseHandle, IsDir, Offset, *Size, Data,
+ CommonResp.Error));
+ Status = VirtioFsErrnoToEfiStatus (CommonResp.Error);
+ }
+ return Status;
+ }
+
+ //
+ // Report the actual transfer size.
+ //
+ // Integer overflow in the (UINT32) cast below is not possible; the
+ // VIRTIO_FS_SCATTER_GATHER_LIST functions would have caught that.
+ //
+ *Size = (UINT32)TailBufferFill;
+ return EFI_SUCCESS;
+}
--
2.19.1.3.g30247aa5d201
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