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| 2560 | 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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| 2590 | jermar | 34 | * @file vfs_open.c |
| 2560 | jermar | 35 | * @brief VFS_OPEN method. |
| 36 | */ |
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| 37 | |||
| 38 | #include <ipc/ipc.h> |
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| 39 | #include <async.h> |
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| 40 | #include <errno.h> |
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| 41 | #include <futex.h> |
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| 2589 | jermar | 42 | #include <sys/types.h> |
| 2593 | jermar | 43 | #include <stdlib.h> |
| 2560 | jermar | 44 | #include "vfs.h" |
| 45 | |||
| 46 | void vfs_open(ipc_callid_t rid, ipc_call_t *request) |
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| 47 | { |
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| 2593 | jermar | 48 | if (!vfs_files_init()) { |
| 2619 | jermar | 49 | ipc_answer_0(rid, ENOMEM); |
| 2589 | jermar | 50 | return; |
| 51 | } |
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| 2590 | jermar | 52 | |
| 53 | /* |
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| 54 | * The POSIX interface is open(path, flags, mode). |
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| 55 | * We can receive flags and mode along with the VFS_OPEN call; the path |
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| 56 | * will need to arrive in another call. |
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| 57 | */ |
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| 58 | int flags = IPC_GET_ARG1(*request); |
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| 59 | int mode = IPC_GET_ARG2(*request); |
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| 60 | size_t size; |
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| 61 | |||
| 62 | ipc_callid_t callid; |
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| 63 | |||
| 2619 | jermar | 64 | if (!ipc_data_receive(&callid, NULL, &size)) { |
| 65 | ipc_answer_0(callid, EINVAL); |
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| 66 | ipc_answer_0(rid, EINVAL); |
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| 2590 | jermar | 67 | return; |
| 68 | } |
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| 69 | |||
| 70 | /* |
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| 71 | * Now we are on the verge of accepting the path. |
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| 72 | * |
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| 73 | * There is one optimization we could do in the future: copy the path |
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| 74 | * directly into the PLB using some kind of a callback. |
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| 75 | */ |
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| 76 | char *path = malloc(size); |
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| 77 | |||
| 78 | if (!path) { |
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| 2619 | jermar | 79 | ipc_answer_0(callid, ENOMEM); |
| 80 | ipc_answer_0(rid, ENOMEM); |
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| 2590 | jermar | 81 | return; |
| 82 | } |
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| 83 | |||
| 84 | int rc; |
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| 2619 | jermar | 85 | if ((rc = ipc_data_deliver(callid, path, size))) { |
| 86 | ipc_answer_0(rid, rc); |
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| 2590 | jermar | 87 | free(path); |
| 88 | return; |
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| 89 | } |
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| 90 | |||
| 91 | /* |
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| 2593 | jermar | 92 | * Avoid the race condition in which the file can be deleted before we |
| 93 | * find/create-and-lock the VFS node corresponding to the looked-up |
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| 94 | * triplet. |
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| 95 | */ |
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| 96 | futex_down(&unlink_futex); |
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| 97 | |||
| 98 | /* |
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| 2590 | jermar | 99 | * The path is now populated and we can call vfs_lookup_internal(). |
| 100 | */ |
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| 101 | vfs_triplet_t triplet; |
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| 102 | rc = vfs_lookup_internal(path, size, &triplet, NULL); |
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| 103 | if (rc) { |
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| 2593 | jermar | 104 | futex_up(&unlink_futex); |
| 2619 | jermar | 105 | ipc_answer_0(rid, rc); |
| 2590 | jermar | 106 | free(path); |
| 107 | return; |
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| 108 | } |
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| 109 | |||
| 110 | /* |
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| 111 | * Path is no longer needed. |
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| 112 | */ |
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| 113 | free(path); |
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| 114 | |||
| 115 | vfs_node_t *node = vfs_node_get(&triplet); |
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| 2593 | jermar | 116 | futex_up(&unlink_futex); |
| 117 | |||
| 118 | /* |
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| 119 | * Get ourselves a file descriptor and the corresponding vfs_file_t |
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| 120 | * structure. |
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| 121 | */ |
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| 122 | int fd = vfs_fd_alloc(); |
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| 123 | if (fd < 0) { |
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| 124 | vfs_node_put(node); |
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| 2619 | jermar | 125 | ipc_answer_0(rid, fd); |
| 2593 | jermar | 126 | return; |
| 127 | } |
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| 128 | vfs_file_t *file = vfs_file_get(fd); |
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| 129 | file->node = node; |
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| 130 | |||
| 131 | /* |
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| 132 | * The following increase in reference count is for the fact that the |
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| 133 | * file is being opened and that a file structure is pointing to it. |
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| 134 | * It is necessary so that the file will not disappear when |
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| 135 | * vfs_node_put() is called. The reference will be dropped by the |
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| 136 | * respective VFS_CLOSE. |
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| 137 | */ |
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| 138 | vfs_node_addref(node); |
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| 139 | vfs_node_put(node); |
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| 140 | |||
| 141 | /* |
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| 142 | * Success! Return the new file descriptor to the client. |
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| 143 | */ |
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| 2619 | jermar | 144 | ipc_answer_1(rid, EOK, fd); |
| 2560 | jermar | 145 | } |
| 146 | |||
| 147 | /** |
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| 148 | * @} |
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| 149 | */ |