source: MondoRescue/branches/2.2.5/mindi-busybox/util-linux/mdev.c

Last change on this file was 1765, checked in by Bruno Cornec, 16 years ago

Update to busybox 1.7.2
File size: 7.9 KB
Line 
1/* vi: set sw=4 ts=4: */
2/*
3 *
4 * mdev - Mini udev for busybox
5 *
6 * Copyright 2005 Rob Landley <rob@landley.net>
7 * Copyright 2005 Frank Sorenson <frank@tuxrocks.com>
8 *
9 * Licensed under GPL version 2, see file LICENSE in this tarball for details.
10 */
11
12#include "libbb.h"
13#include "xregex.h"
14
15struct globals {
16 int root_major, root_minor;
17};
18#define G (*(struct globals*)&bb_common_bufsiz1)
19#define root_major (G.root_major)
20#define root_minor (G.root_minor)
21
22#define MAX_SYSFS_DEPTH 3 /* prevent infinite loops in /sys symlinks */
23
24/* mknod in /dev based on a path like "/sys/block/hda/hda1" */
25static void make_device(char *path, int delete)
26{
27 const char *device_name;
28 int major, minor, type, len;
29 int mode = 0660;
30 uid_t uid = 0;
31 gid_t gid = 0;
32 char *temp = path + strlen(path);
33 char *command = NULL;
34
35 /* Try to read major/minor string. Note that the kernel puts \n after
36 * the data, so we don't need to worry about null terminating the string
37 * because sscanf() will stop at the first nondigit, which \n is. We
38 * also depend on path having writeable space after it. */
39
40 if (!delete) {
41 strcat(path, "/dev");
42 len = open_read_close(path, temp + 1, 64);
43 *temp++ = 0;
44 if (len < 1) return;
45 }
46
47 /* Determine device name, type, major and minor */
48
49 device_name = bb_basename(path);
50 type = path[5]=='c' ? S_IFCHR : S_IFBLK;
51
52 /* If we have a config file, look up permissions for this device */
53
54 if (ENABLE_FEATURE_MDEV_CONF) {
55 char *conf, *pos, *end;
56 int line, fd;
57
58 /* mmap the config file */
59 fd = open("/etc/mdev.conf", O_RDONLY);
60 if (fd < 0)
61 goto end_parse;
62 len = xlseek(fd, 0, SEEK_END);
63 conf = mmap(NULL, len, PROT_READ, MAP_PRIVATE, fd, 0);
64 close(fd);
65 if (!conf)
66 goto end_parse;
67
68 line = 0;
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 == 0) {
91 /* Regex to match this device */
92
93 char *regex = xstrndup(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 free(regex);
103
104 /* If not this device, skip rest of line */
105 if (result || off.rm_so
106 || off.rm_eo != strlen(device_name))
107 break;
108 }
109 if (field == 1) {
110 /* uid:gid */
111
112 char *s, *s2;
113
114 /* Find : */
115 for (s=pos; s<end2 && *s!=':'; s++)
116 ;
117 if (s == end2) break;
118
119 /* Parse UID */
120 uid = strtoul(pos, &s2, 10);
121 if (s != s2) {
122 struct passwd *pass;
123 char *_unam = xstrndup(pos, s-pos);
124 pass = getpwnam(_unam);
125 free(_unam);
126 if (!pass) break;
127 uid = pass->pw_uid;
128 }
129 s++;
130 /* parse GID */
131 gid = strtoul(s, &s2, 10);
132 if (end2 != s2) {
133 struct group *grp;
134 char *_grnam = xstrndup(s, end2-s);
135 grp = getgrnam(_grnam);
136 free(_grnam);
137 if (!grp) break;
138 gid = grp->gr_gid;
139 }
140 }
141 if (field == 2) {
142 /* mode */
143
144 mode = strtoul(pos, &pos, 8);
145 if (pos != end2) break;
146 }
147 if (ENABLE_FEATURE_MDEV_EXEC && field == 3) {
148 // Command to run
149 const char *s = "@$*";
150 const char *s2;
151 s2 = strchr(s, *pos++);
152 if (!s2) {
153 // Force error
154 field = 1;
155 break;
156 }
157 if ((s2-s+1) & (1<<delete))
158 command = xstrndup(pos, end-pos);
159 }
160
161 pos = end2;
162 }
163
164 /* Did everything parse happily? */
165
166 if (field > 2) break;
167 if (field) bb_error_msg_and_die("bad line %d",line);
168
169 /* Next line */
170 pos = ++end;
171 }
172 munmap(conf, len);
173 end_parse: /* nothing */ ;
174 }
175
176 umask(0);
177 if (!delete) {
178 if (sscanf(temp, "%d:%d", &major, &minor) != 2) return;
179 if (mknod(device_name, mode | type, makedev(major, minor)) && errno != EEXIST)
180 bb_perror_msg_and_die("mknod %s", device_name);
181
182 if (major == root_major && minor == root_minor)
183 symlink(device_name, "root");
184
185 if (ENABLE_FEATURE_MDEV_CONF) chown(device_name, uid, gid);
186 }
187 if (command) {
188 /* setenv will leak memory, so use putenv */
189 char *s = xasprintf("MDEV=%s", device_name);
190 putenv(s);
191 if (system(command) == -1)
192 bb_perror_msg_and_die("cannot run %s", command);
193 s[4] = '\0';
194 unsetenv(s);
195 free(s);
196 free(command);
197 }
198 if (delete) unlink(device_name);
199}
200
201/* File callback for /sys/ traversal */
202static int fileAction(const char *fileName, struct stat *statbuf,
203 void *userData, int depth)
204{
205 size_t len = strlen(fileName) - 4;
206 char *scratch = userData;
207
208 if (strcmp(fileName + len, "/dev"))
209 return FALSE;
210
211 strcpy(scratch, fileName);
212 scratch[len] = 0;
213 make_device(scratch, 0);
214
215 return TRUE;
216}
217
218/* Directory callback for /sys/ traversal */
219static int dirAction(const char *fileName, struct stat *statbuf,
220 void *userData, int depth)
221{
222 return (depth >= MAX_SYSFS_DEPTH ? SKIP : TRUE);
223}
224
225/* For the full gory details, see linux/Documentation/firmware_class/README
226 *
227 * Firmware loading works like this:
228 * - kernel sets FIRMWARE env var
229 * - userspace checks /lib/firmware/$FIRMWARE
230 * - userspace waits for /sys/$DEVPATH/loading to appear
231 * - userspace writes "1" to /sys/$DEVPATH/loading
232 * - userspace copies /lib/firmware/$FIRMWARE into /sys/$DEVPATH/data
233 * - userspace writes "0" (worked) or "-1" (failed) to /sys/$DEVPATH/loading
234 * - kernel loads firmware into device
235 */
236static void load_firmware(const char *const firmware, const char *const sysfs_path)
237{
238 int cnt;
239 int firmware_fd, loading_fd, data_fd;
240
241 /* check for $FIRMWARE from kernel */
242 /* XXX: dont bother: open(NULL) works same as open("no-such-file")
243 * if (!firmware)
244 * return;
245 */
246
247 /* check for /lib/firmware/$FIRMWARE */
248 xchdir("/lib/firmware");
249 firmware_fd = xopen(firmware, O_RDONLY);
250
251 /* in case we goto out ... */
252 data_fd = -1;
253
254 /* check for /sys/$DEVPATH/loading ... give 30 seconds to appear */
255 xchdir(sysfs_path);
256 for (cnt = 0; cnt < 30; ++cnt) {
257 loading_fd = open("loading", O_WRONLY);
258 if (loading_fd == -1)
259 sleep(1);
260 else
261 break;
262 }
263 if (loading_fd == -1)
264 goto out;
265
266 /* tell kernel we're loading by `echo 1 > /sys/$DEVPATH/loading` */
267 if (write(loading_fd, "1", 1) != 1)
268 goto out;
269
270 /* load firmware by `cat /lib/firmware/$FIRMWARE > /sys/$DEVPATH/data */
271 data_fd = open("data", O_WRONLY);
272 if (data_fd == -1)
273 goto out;
274 cnt = bb_copyfd_eof(firmware_fd, data_fd);
275
276 /* tell kernel result by `echo [0|-1] > /sys/$DEVPATH/loading` */
277 if (cnt > 0)
278 write(loading_fd, "0", 1);
279 else
280 write(loading_fd, "-1", 2);
281
282 out:
283 if (ENABLE_FEATURE_CLEAN_UP) {
284 close(firmware_fd);
285 close(loading_fd);
286 close(data_fd);
287 }
288}
289
290int mdev_main(int argc, char **argv);
291int mdev_main(int argc, char **argv)
292{
293 char *action;
294 char *env_path;
295 RESERVE_CONFIG_BUFFER(temp,PATH_MAX);
296
297 xchdir("/dev");
298
299 /* Scan */
300
301 if (argc == 2 && !strcmp(argv[1],"-s")) {
302 struct stat st;
303
304 xstat("/", &st);
305 root_major = major(st.st_dev);
306 root_minor = minor(st.st_dev);
307
308 recursive_action("/sys/block",
309 ACTION_RECURSE | ACTION_FOLLOWLINKS,
310 fileAction, dirAction, temp, 0);
311
312 recursive_action("/sys/class",
313 ACTION_RECURSE | ACTION_FOLLOWLINKS,
314 fileAction, dirAction, temp, 0);
315
316 /* Hotplug */
317
318 } else {
319 action = getenv("ACTION");
320 env_path = getenv("DEVPATH");
321 if (!action || !env_path)
322 bb_show_usage();
323
324 sprintf(temp, "/sys%s", env_path);
325 if (!strcmp(action, "remove"))
326 make_device(temp, 1);
327 else if (!strcmp(action, "add")) {
328 make_device(temp, 0);
329
330 if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE)
331 load_firmware(getenv("FIRMWARE"), temp);
332 }
333 }
334
335 if (ENABLE_FEATURE_CLEAN_UP) RELEASE_CONFIG_BUFFER(temp);
336 return 0;
337}
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