Rev 2593 | Go to most recent revision | Details | Compare with Previous | Last modification | View Log | RSS feed
Rev | Author | Line No. | Line |
---|---|---|---|
2560 | jermar | 1 | /* |
2 | * Copyright (c) 2007 Jakub Jermar |
||
3 | * All rights reserved. |
||
4 | * |
||
5 | * Redistribution and use in source and binary forms, with or without |
||
6 | * modification, are permitted provided that the following conditions |
||
7 | * are met: |
||
8 | * |
||
9 | * - Redistributions of source code must retain the above copyright |
||
10 | * notice, this list of conditions and the following disclaimer. |
||
11 | * - Redistributions in binary form must reproduce the above copyright |
||
12 | * notice, this list of conditions and the following disclaimer in the |
||
13 | * documentation and/or other materials provided with the distribution. |
||
14 | * - The name of the author may not be used to endorse or promote products |
||
15 | * derived from this software without specific prior written permission. |
||
16 | * |
||
17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
||
18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
||
19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
||
20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
||
21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
||
22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
||
23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
||
24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
||
25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
||
26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
||
27 | */ |
||
28 | |||
29 | /** @addtogroup fs |
||
30 | * @{ |
||
31 | */ |
||
32 | |||
33 | /** |
||
2590 | jermar | 34 | * @file vfs_open.c |
2560 | jermar | 35 | * @brief VFS_OPEN method. |
36 | */ |
||
37 | |||
38 | #include <ipc/ipc.h> |
||
39 | #include <async.h> |
||
40 | #include <errno.h> |
||
41 | #include <futex.h> |
||
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) |
||
47 | { |
||
2593 | jermar | 48 | if (!vfs_files_init()) { |
2619 | jermar | 49 | ipc_answer_0(rid, ENOMEM); |
2589 | jermar | 50 | return; |
51 | } |
||
2590 | jermar | 52 | |
53 | /* |
||
54 | * The POSIX interface is open(path, flags, mode). |
||
55 | * We can receive flags and mode along with the VFS_OPEN call; the path |
||
56 | * will need to arrive in another call. |
||
57 | */ |
||
58 | int flags = IPC_GET_ARG1(*request); |
||
59 | int mode = IPC_GET_ARG2(*request); |
||
60 | size_t size; |
||
61 | |||
62 | ipc_callid_t callid; |
||
63 | |||
2619 | jermar | 64 | if (!ipc_data_receive(&callid, NULL, &size)) { |
65 | ipc_answer_0(callid, EINVAL); |
||
66 | ipc_answer_0(rid, EINVAL); |
||
2590 | jermar | 67 | return; |
68 | } |
||
69 | |||
70 | /* |
||
71 | * Now we are on the verge of accepting the path. |
||
72 | * |
||
73 | * There is one optimization we could do in the future: copy the path |
||
74 | * directly into the PLB using some kind of a callback. |
||
75 | */ |
||
76 | char *path = malloc(size); |
||
77 | |||
78 | if (!path) { |
||
2619 | jermar | 79 | ipc_answer_0(callid, ENOMEM); |
80 | ipc_answer_0(rid, ENOMEM); |
||
2590 | jermar | 81 | return; |
82 | } |
||
83 | |||
84 | int rc; |
||
2619 | jermar | 85 | if ((rc = ipc_data_deliver(callid, path, size))) { |
86 | ipc_answer_0(rid, rc); |
||
2590 | jermar | 87 | free(path); |
88 | return; |
||
89 | } |
||
90 | |||
91 | /* |
||
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 |
||
94 | * triplet. |
||
95 | */ |
||
96 | futex_down(&unlink_futex); |
||
97 | |||
98 | /* |
||
2590 | jermar | 99 | * The path is now populated and we can call vfs_lookup_internal(). |
100 | */ |
||
101 | vfs_triplet_t triplet; |
||
102 | rc = vfs_lookup_internal(path, size, &triplet, NULL); |
||
103 | if (rc) { |
||
2593 | jermar | 104 | futex_up(&unlink_futex); |
2619 | jermar | 105 | ipc_answer_0(rid, rc); |
2590 | jermar | 106 | free(path); |
107 | return; |
||
108 | } |
||
109 | |||
110 | /* |
||
111 | * Path is no longer needed. |
||
112 | */ |
||
113 | free(path); |
||
114 | |||
115 | vfs_node_t *node = vfs_node_get(&triplet); |
||
2593 | jermar | 116 | futex_up(&unlink_futex); |
117 | |||
118 | /* |
||
119 | * Get ourselves a file descriptor and the corresponding vfs_file_t |
||
120 | * structure. |
||
121 | */ |
||
122 | int fd = vfs_fd_alloc(); |
||
123 | if (fd < 0) { |
||
124 | vfs_node_put(node); |
||
2619 | jermar | 125 | ipc_answer_0(rid, fd); |
2593 | jermar | 126 | return; |
127 | } |
||
128 | vfs_file_t *file = vfs_file_get(fd); |
||
129 | file->node = node; |
||
130 | |||
131 | /* |
||
132 | * The following increase in reference count is for the fact that the |
||
133 | * file is being opened and that a file structure is pointing to it. |
||
134 | * It is necessary so that the file will not disappear when |
||
135 | * vfs_node_put() is called. The reference will be dropped by the |
||
136 | * respective VFS_CLOSE. |
||
137 | */ |
||
138 | vfs_node_addref(node); |
||
139 | vfs_node_put(node); |
||
140 | |||
141 | /* |
||
142 | * Success! Return the new file descriptor to the client. |
||
143 | */ |
||
2619 | jermar | 144 | ipc_answer_1(rid, EOK, fd); |
2560 | jermar | 145 | } |
146 | |||
147 | /** |
||
148 | * @} |
||
149 | */ |