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1 | /** @file\r |
2 | FUSE_READ / FUSE_READDIRPLUS wrapper for the Virtio Filesystem device.\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 | #include "VirtioFsDxe.h"\r | |
10 | \r | |
11 | /**\r | |
12 | Read a chunk from a regular file or a directory stream, by sending the\r | |
13 | FUSE_READ / FUSE_READDIRPLUS request to the Virtio Filesystem device.\r | |
14 | \r | |
15 | The function may only be called after VirtioFsFuseInitSession() returns\r | |
16 | successfully and before VirtioFsUninit() is called.\r | |
17 | \r | |
18 | @param[in,out] VirtioFs The Virtio Filesystem device to send the FUSE_READ\r | |
19 | or FUSE_READDIRPLUS request to. On output, the FUSE\r | |
20 | request counter "VirtioFs->RequestId" will have been\r | |
21 | incremented.\r | |
22 | \r | |
23 | @param[in] NodeId The inode number of the regular file or directory\r | |
24 | stream to read from.\r | |
25 | \r | |
26 | @param[in] FuseHandle The open handle to the regular file or directory\r | |
27 | stream to read from.\r | |
28 | \r | |
29 | @param[in] IsDir TRUE if NodeId and FuseHandle refer to a directory,\r | |
30 | FALSE if NodeId and FuseHandle refer to a regular\r | |
31 | file.\r | |
32 | \r | |
33 | @param[in] Offset If IsDir is FALSE: the absolute file position at\r | |
34 | which to start reading.\r | |
35 | \r | |
36 | If IsDir is TRUE: the directory stream cookie at\r | |
37 | which to start or continue reading. The zero-valued\r | |
38 | cookie identifies the start of the directory stream.\r | |
39 | Further positions in the directory stream can be\r | |
40 | passed in from the CookieForNextEntry field of\r | |
41 | VIRTIO_FS_FUSE_DIRENTPLUS_RESPONSE.\r | |
42 | \r | |
43 | @param[in,out] Size On input, the number of bytes to read. On successful\r | |
44 | return, the number of bytes actually read, which may\r | |
45 | be smaller than the value on input.\r | |
46 | \r | |
47 | When reading a regular file (i.e., when IsDir is\r | |
48 | FALSE), EOF can be detected by passing in a nonzero\r | |
49 | Size, and finding a zero Size on output.\r | |
50 | \r | |
51 | When reading a directory stream (i.e., when IsDir is\r | |
52 | TRUE), Data consists of a sequence of variably-sized\r | |
53 | records (directory entries). A read operation\r | |
54 | returns the maximal sequence of records that fits in\r | |
55 | Size, without having to truncate a record. In order\r | |
56 | to guarantee progress, call\r | |
57 | \r | |
58 | VirtioFsFuseStatFs (VirtioFs, NodeId,\r | |
59 | &FilesysAttr)\r | |
60 | \r | |
61 | first, to learn the maximum Namelen for the\r | |
62 | directory stream. Then assign Size at least\r | |
63 | \r | |
64 | VIRTIO_FS_FUSE_DIRENTPLUS_RESPONSE_SIZE (\r | |
65 | FilesysAttr.Namelen)\r | |
66 | \r | |
67 | on input. (Remember that\r | |
68 | VIRTIO_FS_FUSE_DIRENTPLUS_RESPONSE_SIZE() may return\r | |
69 | 0 if its Namelen argument is invalid.) EOF can be\r | |
70 | detected if Size is set on input like described\r | |
71 | above, and Size is zero on output.\r | |
72 | \r | |
73 | @param[out] Data Buffer to read the bytes from the regular file or\r | |
74 | the directory stream into. The caller is responsible\r | |
75 | for providing room for (at least) as many bytes in\r | |
76 | Data as Size is on input.\r | |
77 | \r | |
78 | @retval EFI_SUCCESS Read successful. The caller is responsible for checking\r | |
79 | Size to learn the actual byte count transferred.\r | |
80 | \r | |
81 | @return The "errno" value mapped to an EFI_STATUS code, if the\r | |
82 | Virtio Filesystem device explicitly reported an error.\r | |
83 | \r | |
84 | @return Error codes propagated from VirtioFsSgListsValidate(),\r | |
85 | VirtioFsFuseNewRequest(), VirtioFsSgListsSubmit(),\r | |
86 | VirtioFsFuseCheckResponse().\r | |
87 | **/\r | |
88 | EFI_STATUS\r | |
89 | VirtioFsFuseReadFileOrDir (\r | |
ac0a286f MK |
90 | IN OUT VIRTIO_FS *VirtioFs,\r |
91 | IN UINT64 NodeId,\r | |
92 | IN UINT64 FuseHandle,\r | |
93 | IN BOOLEAN IsDir,\r | |
94 | IN UINT64 Offset,\r | |
95 | IN OUT UINT32 *Size,\r | |
96 | OUT VOID *Data\r | |
d98d7e30 LE |
97 | )\r |
98 | {\r | |
ac0a286f MK |
99 | VIRTIO_FS_FUSE_REQUEST CommonReq;\r |
100 | VIRTIO_FS_FUSE_READ_REQUEST ReadReq;\r | |
101 | VIRTIO_FS_IO_VECTOR ReqIoVec[2];\r | |
102 | VIRTIO_FS_SCATTER_GATHER_LIST ReqSgList;\r | |
103 | VIRTIO_FS_FUSE_RESPONSE CommonResp;\r | |
104 | VIRTIO_FS_IO_VECTOR RespIoVec[2];\r | |
105 | VIRTIO_FS_SCATTER_GATHER_LIST RespSgList;\r | |
106 | EFI_STATUS Status;\r | |
107 | UINTN TailBufferFill;\r | |
d98d7e30 LE |
108 | \r |
109 | //\r | |
110 | // Set up the scatter-gather lists.\r | |
111 | //\r | |
112 | ReqIoVec[0].Buffer = &CommonReq;\r | |
113 | ReqIoVec[0].Size = sizeof CommonReq;\r | |
114 | ReqIoVec[1].Buffer = &ReadReq;\r | |
115 | ReqIoVec[1].Size = sizeof ReadReq;\r | |
116 | ReqSgList.IoVec = ReqIoVec;\r | |
117 | ReqSgList.NumVec = ARRAY_SIZE (ReqIoVec);\r | |
118 | \r | |
119 | RespIoVec[0].Buffer = &CommonResp;\r | |
120 | RespIoVec[0].Size = sizeof CommonResp;\r | |
121 | RespIoVec[1].Buffer = Data;\r | |
122 | RespIoVec[1].Size = *Size;\r | |
123 | RespSgList.IoVec = RespIoVec;\r | |
124 | RespSgList.NumVec = ARRAY_SIZE (RespIoVec);\r | |
125 | \r | |
126 | //\r | |
127 | // Validate the scatter-gather lists; calculate the total transfer sizes.\r | |
128 | //\r | |
129 | Status = VirtioFsSgListsValidate (VirtioFs, &ReqSgList, &RespSgList);\r | |
130 | if (EFI_ERROR (Status)) {\r | |
131 | return Status;\r | |
132 | }\r | |
133 | \r | |
134 | //\r | |
135 | // Populate the common request header.\r | |
136 | //\r | |
137 | Status = VirtioFsFuseNewRequest (\r | |
138 | VirtioFs,\r | |
139 | &CommonReq,\r | |
140 | ReqSgList.TotalSize,\r | |
141 | IsDir ? VirtioFsFuseOpReadDirPlus : VirtioFsFuseOpRead,\r | |
142 | NodeId\r | |
143 | );\r | |
144 | if (EFI_ERROR (Status)) {\r | |
145 | return Status;\r | |
146 | }\r | |
147 | \r | |
148 | //\r | |
149 | // Populate the FUSE_READ- / FUSE_READDIRPLUS-specific fields.\r | |
150 | //\r | |
151 | ReadReq.FileHandle = FuseHandle;\r | |
152 | ReadReq.Offset = Offset;\r | |
153 | ReadReq.Size = *Size;\r | |
154 | ReadReq.ReadFlags = 0;\r | |
155 | ReadReq.LockOwner = 0;\r | |
156 | ReadReq.Flags = 0;\r | |
157 | ReadReq.Padding = 0;\r | |
158 | \r | |
159 | //\r | |
160 | // Submit the request.\r | |
161 | //\r | |
162 | Status = VirtioFsSgListsSubmit (VirtioFs, &ReqSgList, &RespSgList);\r | |
163 | if (EFI_ERROR (Status)) {\r | |
164 | return Status;\r | |
165 | }\r | |
166 | \r | |
167 | //\r | |
168 | // Verify the response. Note that TailBufferFill is variable.\r | |
169 | //\r | |
ac0a286f MK |
170 | Status = VirtioFsFuseCheckResponse (\r |
171 | &RespSgList,\r | |
172 | CommonReq.Unique,\r | |
173 | &TailBufferFill\r | |
174 | );\r | |
d98d7e30 LE |
175 | if (EFI_ERROR (Status)) {\r |
176 | if (Status == EFI_DEVICE_ERROR) {\r | |
ac0a286f MK |
177 | DEBUG ((\r |
178 | DEBUG_ERROR,\r | |
179 | "%a: Label=\"%s\" NodeId=%Lu FuseHandle=%Lu "\r | |
180 | "IsDir=%d Offset=0x%Lx Size=0x%x Data@%p Errno=%d\n",\r | |
181 | __FUNCTION__,\r | |
182 | VirtioFs->Label,\r | |
183 | NodeId,\r | |
184 | FuseHandle,\r | |
185 | IsDir,\r | |
186 | Offset,\r | |
187 | *Size,\r | |
188 | Data,\r | |
189 | CommonResp.Error\r | |
190 | ));\r | |
d98d7e30 LE |
191 | Status = VirtioFsErrnoToEfiStatus (CommonResp.Error);\r |
192 | }\r | |
ac0a286f | 193 | \r |
d98d7e30 LE |
194 | return Status;\r |
195 | }\r | |
196 | \r | |
197 | //\r | |
198 | // Report the actual transfer size.\r | |
199 | //\r | |
200 | // Integer overflow in the (UINT32) cast below is not possible; the\r | |
201 | // VIRTIO_FS_SCATTER_GATHER_LIST functions would have caught that.\r | |
202 | //\r | |
203 | *Size = (UINT32)TailBufferFill;\r | |
204 | return EFI_SUCCESS;\r | |
205 | }\r |