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| Rev | Author | Line No. | Line |
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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 | int fd = IPC_GET_ARG1(*request); |
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| 57 | |||
| 58 | /* |
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| 59 | * Lookup the file structure corresponding to the file descriptor. |
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| 60 | */ |
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| 61 | vfs_file_t *file = vfs_file_get(fd); |
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| 62 | if (!file) { |
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| 63 | ipc_answer_0(rid, ENOENT); |
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| 64 | return; |
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| 65 | } |
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| 66 | |||
| 67 | /* |
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| 2663 | jermar | 68 | * Now we need to receive a call with client's IPC_M_DATA_READ request. |
| 2625 | jermar | 69 | */ |
| 70 | ipc_callid_t callid; |
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| 2663 | jermar | 71 | if (!ipc_data_read_receive(&callid, NULL)) { |
| 2625 | jermar | 72 | ipc_answer_0(callid, EINVAL); |
| 73 | ipc_answer_0(rid, EINVAL); |
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| 74 | return; |
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| 75 | } |
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| 76 | |||
| 77 | int fs_phone = vfs_grab_phone(file->node->fs_handle); |
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| 78 | |||
| 79 | /* |
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| 80 | * Make a VFS_READ request at the destination FS server. |
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| 81 | */ |
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| 82 | aid_t msg; |
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| 2658 | jermar | 83 | ipc_call_t answer; |
| 2663 | jermar | 84 | msg = async_send_3(fs_phone, VFS_READ, file->node->dev_handle, |
| 85 | file->node->index, file->pos, &answer); |
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| 2625 | jermar | 86 | |
| 87 | /* |
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| 2663 | jermar | 88 | * Forward the IPC_M_DATA_READ request to the destination FS server. |
| 89 | * The call will be routed as if sent by ourselves. Note that call |
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| 90 | * arguments are immutable in this case so we don't have to bother. |
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| 2625 | jermar | 91 | */ |
| 2663 | jermar | 92 | ipc_forward_fast(callid, fs_phone, 0, 0, 0, IPC_FF_ROUTE_FROM_ME); |
| 2625 | jermar | 93 | |
| 94 | vfs_release_phone(fs_phone); |
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| 95 | |||
| 96 | /* |
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| 97 | * Wait for reply from the FS server. |
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| 98 | */ |
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| 99 | ipcarg_t rc; |
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| 100 | async_wait_for(msg, &rc); |
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| 2658 | jermar | 101 | size_t bytes = IPC_GET_ARG1(answer); |
| 2625 | jermar | 102 | |
| 103 | /* |
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| 2659 | jermar | 104 | * Update the position pointer. |
| 105 | */ |
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| 106 | file->pos += bytes; |
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| 107 | |||
| 108 | /* |
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| 2625 | jermar | 109 | * FS server's reply is the final result of the whole operation we |
| 110 | * return to the client. |
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| 111 | */ |
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| 2658 | jermar | 112 | ipc_answer_1(rid, rc, bytes); |
| 2625 | jermar | 113 | } |
| 114 | |||
| 115 | /** |
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| 116 | * @} |
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| 117 | */ |