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
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
|
/* mdev.c - Populate /dev directory and handle hotplug events
*
* Copyright 2005, 2008 Rob Landley <rob@landley.net>
* Copyright 2005 Frank Sorenson <frank@tuxrocks.com>
USE_MDEV(NEWTOY(mdev, "s", TOYFLAG_USR|TOYFLAG_BIN|TOYFLAG_UMASK))
config MDEV
bool "mdev"
default n
help
usage: mdev [-s]
Create devices in /dev using information from /sys.
-s Scan all entries in /sys to populate /dev.
config MDEV_CONF
bool "Configuration file for mdev"
default y
depends on MDEV
help
The mdev config file (/etc/mdev.conf) contains lines that look like:
hd[a-z][0-9]* 0:3 660
Each line must contain three whitespace separated fields. The first
field is a regular expression matching one or more device names, and
the second and third fields are uid:gid and file permissions for
matching devies.
*/
#include "toys.h"
#include "lib/xregcomp.h"
// todo, open() block devices to trigger partition scanning.
// mknod in /dev based on a path like "/sys/block/hda/hda1"
static void make_device(char *path)
{
char *device_name, *s, *temp;
int major, minor, type, len, fd;
int mode = 0660;
uid_t uid = 0;
gid_t gid = 0;
// Try to read major/minor string
temp = strrchr(path, '/');
fd = open(path, O_RDONLY);
*temp=0;
temp = toybuf;
len = read(fd, temp, 64);
close(fd);
if (len<1) return;
temp[len] = 0;
// Determine device name, type, major and minor
device_name = strrchr(path, '/') + 1;
type = path[5]=='c' ? S_IFCHR : S_IFBLK;
major = minor = 0;
sscanf(temp, "%u:%u", &major, &minor);
// If we have a config file, look up permissions for this device
if (CFG_MDEV_CONF) {
char *conf, *pos, *end;
// mmap the config file
if (-1!=(fd = open("/etc/mdev.conf", O_RDONLY))) {
len = fdlength(fd);
conf = mmap(NULL, len, PROT_READ, MAP_PRIVATE, fd, 0);
if (conf) {
int line = 0;
// Loop through lines in mmaped file
for (pos = conf; pos-conf<len;) {
int field;
char *end2;
line++;
// find end of this line
for(end = pos; end-conf<len && *end!='\n'; end++);
// Three fields: regex, uid:gid, mode
for (field = 3; field; field--) {
// Skip whitespace
while (pos<end && isspace(*pos)) pos++;
if (pos==end || *pos=='#') break;
for (end2 = pos;
end2<end && !isspace(*end2) && *end2!='#'; end2++);
switch(field) {
// Regex to match this device
case 3:
{
char *regex = strndup(pos, end2-pos);
regex_t match;
regmatch_t off;
int result;
// Is this it?
xregcomp(&match, regex, REG_EXTENDED);
result=regexec(&match, device_name, 1, &off, 0);
regfree(&match);
free(regex);
// If not this device, skip rest of line
if (result || off.rm_so
|| off.rm_eo!=strlen(device_name))
goto end_line;
break;
}
// uid:gid
case 2:
{
char *s2;
// Find :
for(s = pos; s<end2 && *s!=':'; s++);
if (s==end2) goto end_line;
// Parse UID
uid = strtoul(pos,&s2,10);
if (s!=s2) {
struct passwd *pass;
char *str = strndup(pos, s-pos);
pass = getpwnam(str);
free(str);
if (!pass) goto end_line;
uid = pass->pw_uid;
}
s++;
// parse GID
gid = strtoul(s,&s2,10);
if (end2!=s2) {
struct group *grp;
char *str = strndup(s, end2-s);
grp = getgrnam(str);
free(str);
if (!grp) goto end_line;
gid = grp->gr_gid;
}
break;
}
// mode
case 1:
{
mode = strtoul(pos, &pos, 8);
if (pos!=end2) goto end_line;
goto found_device;
}
}
pos=end2;
}
end_line:
// Did everything parse happily?
if (field && field!=3) error_exit("Bad line %d", line);
// Next line
pos = ++end;
}
found_device:
munmap(conf, len);
}
close(fd);
}
}
sprintf(temp, "/dev/%s", device_name);
if (mknod(temp, mode | type, makedev(major, minor)) && errno != EEXIST)
perror_exit("mknod %s failed", temp);
if (CFG_MDEV_CONF) mode=chown(temp, uid, gid);
}
static int callback(struct dirtree *node)
{
// Entries in /sys/class/block aren't char devices, so skip 'em. (We'll
// get block devices out of /sys/block.)
if(!strcmp(node->name, "block")) return 0;
// Does this directory have a "dev" entry in it?
// This is path based because the hotplug callbacks are
if (S_ISDIR(node->st.st_mode) || S_ISLNK(node->st.st_mode)) {
int len=4;
char *dev = dirtree_path(node, &len);
strcpy(dev+len, "/dev");
if (!access(dev, R_OK)) make_device(dev);
free(dev);
}
// Circa 2.6.25 the entries more than 2 deep are all either redundant
// (mouse#, event#) or unnamed (every usb_* entry is called "device").
return (node->parent && node->parent->parent) ? 0 : DIRTREE_RECURSE;
}
void mdev_main(void)
{
// Handle -s
if (toys.optflags) {
dirtree_read("/sys/class", callback);
dirtree_read("/sys/block", callback);
}
// hotplug support goes here
}
|
