1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
|
/*
* udev-add.c
*
* Userspace devfs
*
* Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
*
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation version 2 of the License.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include "udev.h"
#include "udev_version.h"
#include "namedev.h"
#include "udevdb.h"
#include "libsysfs/libsysfs.h"
/*
* Right now the major/minor of a device is stored in a file called
* "dev" in sysfs.
* The number is stored as:
* MMmm
* MM is the major
* mm is the minor
* The value is in hex.
* Yes, this will probably change when we go to a bigger major/minor
* range, and will have to be changed at that time.
*/
static int get_major_minor(struct sysfs_class_device *class_dev, int *major, int *minor)
{
int retval = -ENODEV;
char *dev;
dev = sysfs_get_value_from_attributes(class_dev->directory->attributes, "dev");
if (dev == NULL)
goto exit;
dbg("dev = %s", dev);
if (sscanf(dev, "%u:%u", major, minor) != 2)
goto exit;
dbg("found major = %d, minor = %d", *major, *minor);
retval = 0;
exit:
return retval;
}
/*
* We also want to add some permissions here, and possibly some symlinks
*/
static int create_node(char *name, char type, int major, int minor, mode_t mode)
{
char filename[255];
int retval = 0;
strncpy(filename, UDEV_ROOT, sizeof(filename));
strncat(filename, name, sizeof(filename));
switch (type) {
case 'b':
mode |= S_IFBLK;
break;
case 'c':
case 'u':
mode |= S_IFCHR;
break;
case 'p':
mode |= S_IFIFO;
break;
default:
dbg("unknown node type %c\n", type);
return -EINVAL;
}
dbg("mknod(%s, %#o, %u, %u)", filename, mode, major, minor);
retval = mknod(filename, mode, makedev(major, minor));
if (retval)
dbg("mknod(%s, %#o, %u, %u) failed with error '%s'",
filename, mode, major, minor, strerror(errno));
return retval;
}
static struct sysfs_class_device *get_class_dev(char *device_name)
{
char sysfs_path[SYSFS_PATH_MAX];
char dev_path[SYSFS_PATH_MAX];
int retval;
struct sysfs_class_device *class_dev = NULL;
retval = sysfs_get_mnt_path(sysfs_path, SYSFS_PATH_MAX);
dbg("sysfs_path = %s", sysfs_path);
if (retval) {
dbg("sysfs_get_mnt_path failed");
goto exit;
}
strcpy(dev_path, sysfs_path);
strcat(dev_path, device_name);
dbg("looking at %s", dev_path);
/* open up the sysfs class device for this thing... */
class_dev = sysfs_open_class_device(dev_path);
if (class_dev == NULL) {
dbg ("sysfs_open_class_device failed");
goto exit;
}
dbg("class_dev->name = %s", class_dev->name);
exit:
return class_dev;
}
int udev_add_device(char *device, char *subsystem)
{
struct sysfs_class_device *class_dev;
struct device_attr attr;
int major;
int minor;
char type;
int retval = -EINVAL;
/* for now, the block layer is the only place where block devices are */
if (strcmp(subsystem, "block") == 0)
type = 'b';
else
type = 'c';
/* sleep for a second or two to give the kernel a chance to
* create the dev file
*/
sleep(1);
class_dev = get_class_dev(device);
if (class_dev == NULL)
goto exit;
retval = namedev_name_device(class_dev, &attr);
if (retval)
return retval;
retval = get_major_minor(class_dev, &major, &minor);
if (retval) {
dbg("get_major_minor failed");
goto exit;
}
retval = udevdb_add_device(device, class_dev, attr.name, type, major, minor, attr.mode);
if (retval != 0)
dbg("udevdb_add_device failed, but we are going to try to create the node anyway. "
"But remove might not work properly for this device.");
sysfs_close_class_device(class_dev);
return create_node(attr.name, type, major, minor, attr.mode);
exit:
return retval;
}
|
