source: MondoRescue/trunk/mindi-busybox/util-linux/mdev.c@ 956

Last change on this file since 956 was 904, checked in by Bruno Cornec, 17 years ago

merge -r890:902 $SVN_M/branches/stable
File size: 6.1 KB
Line 
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 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
9 */
10
11#include "busybox.h"
12#include <ctype.h>
13#include <errno.h>
14#include <sys/mman.h>
15#include <sys/sysmacros.h>
16#include "xregex.h"
17
18#define DEV_PATH "/dev"
19
20struct mdev_globals
21{
22 int root_major, root_minor;
23} mdev_globals;
24
25#define bbg mdev_globals
26
27/* mknod in /dev based on a path like "/sys/block/hda/hda1" */
28static void make_device(char *path, int delete)
29{
30 char *device_name;
31 int major, minor, type, len, fd;
32 int mode = 0660;
33 uid_t uid = 0;
34 gid_t gid = 0;
35 char *temp = path + strlen(path);
36 char *command = NULL;
37
38 /* Try to read major/minor string. Note that the kernel puts \n after
39 * the data, so we don't need to worry about null terminating the string
40 * because sscanf() will stop at the first nondigit, which \n is. We
41 * also depend on path having writeable space after it. */
42
43 if (!delete) {
44 strcat(path, "/dev");
45 fd = open(path, O_RDONLY);
46 len = read(fd, temp + 1, 64);
47 *temp++ = 0;
48 close(fd);
49 if (len < 1) return;
50 }
51
52 /* Determine device name, type, major and minor */
53
54 device_name = strrchr(path, '/') + 1;
55 type = path[5]=='c' ? S_IFCHR : S_IFBLK;
56
57 /* If we have a config file, look up permissions for this device */
58
59 if (ENABLE_FEATURE_MDEV_CONF) {
60 char *conf, *pos, *end;
61
62 /* mmap the config file */
63 if (-1 != (fd=open("/etc/mdev.conf",O_RDONLY))) {
64 len = lseek(fd, 0, SEEK_END);
65 conf = mmap(NULL, len, PROT_READ, MAP_PRIVATE, fd, 0);
66 if (conf) {
67 int line = 0;
68
69 /* Loop through lines in mmaped file*/
70 for (pos=conf; pos-conf<len;) {
71 int field;
72 char *end2;
73
74 line++;
75 /* find end of this line */
76 for(end=pos; end-conf<len && *end!='\n'; end++)
77 ;
78
79 /* Three fields: regex, uid:gid, mode */
80 for (field=0; field < (3 + ENABLE_FEATURE_MDEV_EXEC);
81 field++)
82 {
83 /* Skip whitespace */
84 while (pos<end && isspace(*pos)) pos++;
85 if (pos==end || *pos=='#') break;
86 for (end2=pos;
87 end2<end && !isspace(*end2) && *end2!='#'; end2++)
88 ;
89
90 if (!field) {
91 /* Regex to match this device */
92
93 char *regex = strndupa(pos, end2-pos);
94 regex_t match;
95 regmatch_t off;
96 int result;
97
98 /* Is this it? */
99 xregcomp(&match,regex, REG_EXTENDED);
100 result = regexec(&match, device_name, 1, &off, 0);
101 regfree(&match);
102
103 /* If not this device, skip rest of line */
104 if (result || off.rm_so
105 || off.rm_eo != strlen(device_name))
106 break;
107
108 } else if (field == 1) {
109 /* uid:gid */
110
111 char *s, *s2;
112
113 /* Find : */
114 for(s=pos; s<end2 && *s!=':'; s++)
115 ;
116 if (s == end2) break;
117
118 /* Parse UID */
119 uid = strtoul(pos,&s2,10);
120 if (s != s2) {
121 struct passwd *pass;
122 pass = getpwnam(strndupa(pos, s-pos));
123 if (!pass) break;
124 uid = pass->pw_uid;
125 }
126 s++;
127 /* parse GID */
128 gid = strtoul(s, &s2, 10);
129 if (end2 != s2) {
130 struct group *grp;
131 grp = getgrnam(strndupa(s, end2-s));
132 if (!grp) break;
133 gid = grp->gr_gid;
134 }
135 } else if (field == 2) {
136 /* mode */
137
138 mode = strtoul(pos, &pos, 8);
139 if (pos != end2) break;
140 } else if (ENABLE_FEATURE_MDEV_EXEC && field == 3) {
141 // Command to run
142 char *s = "@$*", *s2;
143 if (!(s2 = strchr(s, *pos++))) {
144 // Force error
145 field = 1;
146 break;
147 }
148 if ((s2-s+1) & (1<<delete))
149 command = bb_xstrndup(pos, end-pos);
150 }
151
152 pos = end2;
153 }
154
155 /* Did everything parse happily? */
156
157 if (field > 2) break;
158 if (field) bb_error_msg_and_die("Bad line %d",line);
159
160 /* Next line */
161 pos = ++end;
162 }
163 munmap(conf, len);
164 }
165 close(fd);
166 }
167 }
168
169 umask(0);
170 if (!delete) {
171 if (sscanf(temp, "%d:%d", &major, &minor) != 2) return;
172 if (mknod(device_name, mode | type, makedev(major, minor)) && errno != EEXIST)
173 bb_perror_msg_and_die("mknod %s failed", device_name);
174
175 if (major == bbg.root_major && minor == bbg.root_minor)
176 symlink(device_name, "root");
177
178 if (ENABLE_FEATURE_MDEV_CONF) chown(device_name, uid, gid);
179 }
180 if (command) {
181 int rc;
182 char *s;
183
184 s=bb_xasprintf("MDEV=%s",device_name);
185 putenv(s);
186 rc = system(command);
187 s[4]=0;
188 putenv(s);
189 free(s);
190 free(command);
191 if (rc == -1) bb_perror_msg_and_die("Couldn't run %s", command);
192 }
193 if (delete) unlink(device_name);
194}
195
196/* Recursive search of /sys/block or /sys/class. path must be a writeable
197 * buffer of size PATH_MAX containing the directory string to start at. */
198
199static void find_dev(char *path)
200{
201 DIR *dir;
202 size_t len = strlen(path);
203 struct dirent *entry;
204
205 if ((dir = opendir(path)) == NULL)
206 return;
207
208 while ((entry = readdir(dir)) != NULL) {
209 struct stat st;
210
211 /* Skip "." and ".." (also skips hidden files, which is ok) */
212
213 if (entry->d_name[0] == '.')
214 continue;
215
216 // uClibc doesn't fill out entry->d_type reliably. so we use lstat().
217
218 snprintf(path+len, PATH_MAX-len, "/%s", entry->d_name);
219 if (!lstat(path, &st) && S_ISDIR(st.st_mode)) find_dev(path);
220 path[len] = 0;
221
222 /* If there's a dev entry, mknod it */
223
224 if (!strcmp(entry->d_name, "dev")) make_device(path, 0);
225 }
226
227 closedir(dir);
228}
229
230int mdev_main(int argc, char *argv[])
231{
232 char *action;
233 char *env_path;
234 RESERVE_CONFIG_BUFFER(temp,PATH_MAX);
235
236 bb_xchdir(DEV_PATH);
237
238 /* Scan */
239
240 if (argc == 2 && !strcmp(argv[1],"-s")) {
241 struct stat st;
242
243 stat("/", &st); // If this fails, we have bigger problems.
244 bbg.root_major=major(st.st_dev);
245 bbg.root_minor=minor(st.st_dev);
246 strcpy(temp,"/sys/block");
247 find_dev(temp);
248 strcpy(temp,"/sys/class");
249 find_dev(temp);
250
251 /* Hotplug */
252
253 } else {
254 action = getenv("ACTION");
255 env_path = getenv("DEVPATH");
256 if (!action || !env_path)
257 bb_show_usage();
258
259 sprintf(temp, "/sys%s", env_path);
260 if (!strcmp(action, "add")) make_device(temp,0);
261 else if (!strcmp(action, "remove")) make_device(temp,1);
262 }
263
264 if (ENABLE_FEATURE_CLEAN_UP) RELEASE_CONFIG_BUFFER(temp);
265 return 0;
266}
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