comparison toys/mdev.c @ 114:ce6956dfc0cf

Add sync and an incomplete version of mdev.
author Rob Landley <rob@landley.net>
date Mon, 23 Apr 2007 15:45:55 -0400
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children 1e8f4b05cb65
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113:1f7dcdef245c 114:ce6956dfc0cf
1 /* vi:set ts=4:
2 *
3 * mdev - Mini udev for busybox
4 *
5 * Copyright 2005 Rob Landley <rob@landley.net>
6 * Copyright 2005 Frank Sorenson <frank@tuxrocks.com>
7 */
8
9 #include "toys.h"
10 #include "lib/xregcomp.h"
11
12 // mknod in /dev based on a path like "/sys/block/hda/hda1"
13 static void make_device(char *path)
14 {
15 char *device_name, *s, *temp;
16 int major, minor, type, len, fd;
17 int mode = 0660;
18 uid_t uid = 0;
19 gid_t gid = 0;
20
21 // Try to read major/minor string
22
23 temp = path+strlen(path);
24 strcpy(temp, "/dev");
25 fd = open(path, O_RDONLY);
26 *temp=0;
27 temp++;
28 len = read(fd, temp, 64);
29 close(fd);
30 if (len<1) return;
31 temp[len] = 0;
32
33 // Determine device name, type, major and minor
34
35 device_name = strrchr(path, '/') + 1;
36 type = path[5]=='c' ? S_IFCHR : S_IFBLK;
37 major = minor = 0;
38 sscanf(temp, "%u:%u", &major, &minor);
39
40 // If we have a config file, look up permissions for this device
41
42 if (CFG_MDEV_CONF) {
43 char *conf, *pos, *end;
44
45 // mmap the config file
46 if (-1!=(fd = open("/etc/mdev.conf", O_RDONLY))) {
47 len = lseek(fd, 0, SEEK_END);
48 conf = mmap(NULL, len, PROT_READ, MAP_PRIVATE, fd, 0);
49 if (conf) {
50 int line = 0;
51
52 // Loop through lines in mmaped file
53 for (pos = conf; pos-conf<len;) {
54 int field;
55 char *end2;
56
57 line++;
58 // find end of this line
59 for(end = pos; end-conf<len && *end!='\n'; end++);
60
61 // Three fields: regex, uid:gid, mode
62 for (field = 3; field; field--) {
63 // Skip whitespace
64 while (pos<end && isspace(*pos)) pos++;
65 if (pos==end || *pos=='#') break;
66 for (end2 = pos;
67 end2<end && !isspace(*end2) && *end2!='#'; end2++);
68 switch(field) {
69 // Regex to match this device
70 case 3:
71 {
72 char *regex = strndupa(pos, end2-pos);
73 regex_t match;
74 regmatch_t off;
75 int result;
76
77 // Is this it?
78 xregcomp(&match, regex, REG_EXTENDED);
79 result=regexec(&match, device_name, 1, &off, 0);
80 regfree(&match);
81
82 // If not this device, skip rest of line
83 if (result || off.rm_so
84 || off.rm_eo!=strlen(device_name))
85 goto end_line;
86
87 break;
88 }
89 // uid:gid
90 case 2:
91 {
92 char *s2;
93
94 // Find :
95 for(s = pos; s<end2 && *s!=':'; s++);
96 if (s==end2) goto end_line;
97
98 // Parse UID
99 uid = strtoul(pos,&s2,10);
100 if (s!=s2) {
101 struct passwd *pass;
102 pass = getpwnam(strndupa(pos, s-pos));
103 if (!pass) goto end_line;
104 uid = pass->pw_uid;
105 }
106 s++;
107 // parse GID
108 gid = strtoul(s,&s2,10);
109 if (end2!=s2) {
110 struct group *grp;
111 grp = getgrnam(strndupa(s, end2-s));
112 if (!grp) goto end_line;
113 gid = grp->gr_gid;
114 }
115 break;
116 }
117 // mode
118 case 1:
119 {
120 mode = strtoul(pos, &pos, 8);
121 if (pos!=end2) goto end_line;
122 goto found_device;
123 }
124 }
125 pos=end2;
126 }
127 end_line:
128 // Did everything parse happily?
129 if (field && field!=3) error_exit("Bad line %d", line);
130
131 // Next line
132 pos = ++end;
133 }
134 found_device:
135 munmap(conf, len);
136 }
137 close(fd);
138 }
139 }
140
141 sprintf(temp, "/dev/%s", device_name);
142 umask(0);
143 if (mknod(temp, mode | type, makedev(major, minor)) && errno != EEXIST)
144 perror_exit("mknod %s failed", temp);
145
146 if (CFG_MDEV_CONF) chown(temp, uid, gid);
147 }
148
149 // Recursive search of /sys/block or /sys/class. path must be a writeable
150 // buffer of size PATH_MAX containing the directory string to start at.
151
152 static void find_dev(char *path)
153 {
154 DIR *dir;
155 int len=strlen(path);
156
157 if (!(dir = opendir(path)))
158 perror_exit("No %s",path);
159
160 for (;;) {
161 struct dirent *entry = readdir(dir);
162
163 if (!entry) break;
164
165 // Skip "." and ".." (also skips hidden files, which is ok)
166
167 if (entry->d_name[0]=='.') continue;
168
169 if (entry->d_type == DT_DIR) {
170 snprintf(path+len, sizeof(toybuf)-len, "/%s", entry->d_name);
171 find_dev(path);
172 path[len] = 0;
173 }
174
175 // If there's a dev entry, mknod it
176
177 if (strcmp(entry->d_name, "dev")) make_device(path);
178 }
179
180 closedir(dir);
181 }
182
183 int mdev_main(int argc, char *argv[])
184 {
185 if (toys.optflags) {
186 strcpy(toybuf, "/sys/block");
187 find_dev(toybuf);
188 strcpy(toybuf, "/sys/class");
189 find_dev(toybuf);
190 return 0;
191 }
192
193 // hotplug support goes here
194
195 return 0;
196 }