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| 2625 | jermar | 1 | /* |
| 2 | * Copyright (c) 2007 Jakub Jermar |
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| 3 | * All rights reserved. |
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| 4 | * |
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| 5 | * Redistribution and use in source and binary forms, with or without |
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| 6 | * modification, are permitted provided that the following conditions |
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| 7 | * are met: |
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| 8 | * |
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| 9 | * - Redistributions of source code must retain the above copyright |
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| 10 | * notice, this list of conditions and the following disclaimer. |
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| 11 | * - Redistributions in binary form must reproduce the above copyright |
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| 12 | * notice, this list of conditions and the following disclaimer in the |
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| 13 | * documentation and/or other materials provided with the distribution. |
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| 14 | * - The name of the author may not be used to endorse or promote products |
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| 15 | * derived from this software without specific prior written permission. |
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| 16 | * |
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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| 27 | */ |
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| 28 | |||
| 29 | /** @addtogroup fs |
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| 30 | * @{ |
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| 31 | */ |
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| 32 | |||
| 33 | /** |
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| 34 | * @file vfs_read.c |
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| 35 | * @brief |
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| 36 | */ |
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| 37 | |||
| 38 | #include "vfs.h" |
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| 39 | #include <ipc/ipc.h> |
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| 40 | #include <async.h> |
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| 41 | #include <errno.h> |
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| 42 | |||
| 43 | void vfs_read(ipc_callid_t rid, ipc_call_t *request) |
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| 44 | { |
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| 45 | |||
| 46 | /* |
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| 47 | * The following code strongly depends on the fact that the files data |
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| 48 | * structure can be only accessed by a single fibril and all file |
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| 49 | * operations are serialized (i.e. the reads and writes cannot |
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| 50 | * interleave and a file cannot be closed while it is being read). |
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| 51 | * |
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| 2658 | jermar | 52 | * Additional synchronization needs to be added once the table of |
| 2625 | jermar | 53 | * open files supports parallel access! |
| 54 | */ |
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| 55 | |||
| 56 | /* |
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| 57 | * Because we don't support the receive analogy of IPC_M_DATA_SEND, |
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| 58 | * VFS_READ is emulutating its behavior via sharing an address space |
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| 59 | * area. |
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| 60 | */ |
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| 61 | |||
| 62 | int fd = IPC_GET_ARG1(*request); |
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| 2658 | jermar | 63 | size_t size = IPC_GET_ARG2(*request); |
| 2625 | jermar | 64 | |
| 65 | /* |
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| 66 | * Lookup the file structure corresponding to the file descriptor. |
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| 67 | */ |
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| 68 | vfs_file_t *file = vfs_file_get(fd); |
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| 69 | if (!file) { |
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| 70 | ipc_answer_0(rid, ENOENT); |
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| 71 | return; |
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| 72 | } |
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| 73 | |||
| 74 | /* |
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| 75 | * Now we need to receive a call with client's address space area. |
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| 76 | */ |
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| 77 | ipc_callid_t callid; |
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| 78 | ipc_call_t call; |
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| 79 | callid = async_get_call(&call); |
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| 80 | if (IPC_GET_METHOD(call) != IPC_M_AS_AREA_SEND) { |
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| 81 | ipc_answer_0(callid, EINVAL); |
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| 82 | ipc_answer_0(rid, EINVAL); |
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| 83 | return; |
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| 84 | } |
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| 85 | |||
| 86 | int fs_phone = vfs_grab_phone(file->node->fs_handle); |
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| 87 | |||
| 88 | /* |
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| 89 | * Make a VFS_READ request at the destination FS server. |
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| 90 | */ |
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| 91 | aid_t msg; |
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| 2658 | jermar | 92 | ipc_call_t answer; |
| 93 | msg = async_send_4(fs_phone, VFS_READ, file->node->dev_handle, |
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| 94 | file->node->index, file->pos, size, &answer); |
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| 2625 | jermar | 95 | |
| 96 | /* |
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| 97 | * Forward the address space area offer to the destination FS server. |
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| 98 | * The call will be routed as if sent by ourselves. |
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| 99 | */ |
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| 100 | ipc_forward_fast(callid, fs_phone, IPC_GET_METHOD(call), |
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| 2635 | cejka | 101 | IPC_GET_ARG1(call), 0, IPC_FF_ROUTE_FROM_ME); |
| 2625 | jermar | 102 | |
| 103 | vfs_release_phone(fs_phone); |
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| 104 | |||
| 105 | /* |
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| 106 | * Wait for reply from the FS server. |
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| 107 | */ |
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| 108 | ipcarg_t rc; |
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| 109 | async_wait_for(msg, &rc); |
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| 2658 | jermar | 110 | size_t bytes = IPC_GET_ARG1(answer); |
| 2625 | jermar | 111 | |
| 112 | /* |
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| 113 | * FS server's reply is the final result of the whole operation we |
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| 114 | * return to the client. |
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| 115 | */ |
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| 2658 | jermar | 116 | ipc_answer_1(rid, rc, bytes); |
| 2625 | jermar | 117 | } |
| 118 | |||
| 119 | /** |
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| 120 | * @} |
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| 121 | */ |