1 /****************************************************************************
2 * fs/driver/fs_findblockdriver.c
3 *
4 * Licensed to the Apache Software Foundation (ASF) under one or more
5 * contributor license agreements. See the NOTICE file distributed with
6 * this work for additional information regarding copyright ownership. The
7 * ASF licenses this file to you under the Apache License, Version 2.0 (the
8 * "License"); you may not use this file except in compliance with the
9 * License. You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
16 * License for the specific language governing permissions and limitations
17 * under the License.
18 *
19 ****************************************************************************/
20
21 /****************************************************************************
22 * Included Files
23 ****************************************************************************/
24
25 #include "vfs_config.h"
26
27 #include "sys/types.h"
28 #include "sys/mount.h"
29 #include "errno.h"
30 #include "fs/driver.h"
31 #include "string.h"
32
33 /****************************************************************************
34 * Public Functions
35 ****************************************************************************/
36
37 /****************************************************************************
38 * Name: find_blockdriver
39 *
40 * Description:
41 * Return the inode of the block driver specified by 'pathname'
42 *
43 * Input Parameters:
44 * pathname - The full path to the block driver to be located
45 * mountflags - If MS_RDONLY is not set, then driver must support write
46 * operations (see include/sys/mount.h)
47 * ppinode - Address of the location to return the inode reference
48 *
49 * Returned Value:
50 * Returns zero on success or a negated errno on failure:
51 *
52 * ENOENT - No block driver of this name is registered
53 * ENOTBLK - The inode associated with the pathname is not a block driver
54 * EACCESS - The MS_RDONLY option was not set but this driver does not
55 * support write access
56 *
57 ****************************************************************************/
find_blockdriver(const char * pathname,int mountflags,struct Vnode ** vpp)58 int find_blockdriver(const char *pathname, int mountflags, struct Vnode **vpp)
59 {
60 int ret;
61 struct Vnode *vp = NULL;
62
63 /* Sanity checks */
64
65 /* Find the vnode registered with this pathname */
66 VnodeHold();
67 ret = VnodeLookup(pathname, &vp, V_DUMMY);
68 if (ret < 0)
69 {
70 ret = -EACCES;
71 goto errout;
72 }
73
74 /* Verify that the vnode is a block driver. */
75 if (vp->type != VNODE_TYPE_BLK)
76 {
77 PRINT_DEBUG("%s is not a block driver\n", pathname);
78 ret = -ENOTBLK;
79 goto errout;
80 }
81
82 /* Make sure that the vnode supports the requested access */
83
84 struct block_operations *i_bops = (struct block_operations *)((struct drv_data *)vp->data)->ops;
85
86 if (i_bops == NULL || i_bops->read == NULL || (i_bops->write == NULL && (mountflags & MS_RDONLY) == 0))
87 {
88 PRINT_DEBUG("%s does not support requested access\n", pathname);
89 ret = -EACCES;
90 goto errout;
91 }
92
93 *vpp = vp;
94 VnodeDrop();
95 return OK;
96
97 errout:
98 VnodeDrop();
99 return ret;
100 }
101