1 /* vi: set sw=4 ts=4: */
4 * mdev - Mini udev for busybox
6 * Copyright 2005 Rob Landley <rob@landley.net>
7 * Copyright 2005 Frank Sorenson <frank@tuxrocks.com>
9 * Licensed under GPL version 2, see file LICENSE in this tarball for details.
15 #define ENABLE_FEATURE_MDEV_RENAME_REGEXP 1
18 int root_major, root_minor;
20 #define G (*(struct globals*)&bb_common_bufsiz1)
21 #define root_major (G.root_major)
22 #define root_minor (G.root_minor)
24 #define MAX_SYSFS_DEPTH 3 /* prevent infinite loops in /sys symlinks */
26 /* We use additional 64+ bytes in make_device() */
27 #define SCRATCH_SIZE 80
29 static char *next_field(char *s)
31 char *end = skip_non_whitespace(s);
32 s = skip_whitespace(end);
39 /* mknod in /dev based on a path like "/sys/block/hda/hda1" */
40 /* NB: "mdev -s" may call us many times, do not leak memory/fds! */
41 static void make_device(char *path, int delete)
43 const char *device_name;
44 int major, minor, type, len;
48 char *dev_maj_min = path + strlen(path);
52 /* Force the configuration file settings exactly. */
55 /* Try to read major/minor string. Note that the kernel puts \n after
56 * the data, so we don't need to worry about null terminating the string
57 * because sscanf() will stop at the first nondigit, which \n is. We
58 * also depend on path having writeable space after it.
61 strcpy(dev_maj_min, "/dev");
62 len = open_read_close(path, dev_maj_min + 1, 64);
63 *dev_maj_min++ = '\0';
65 if (!ENABLE_FEATURE_MDEV_EXEC)
67 /* no "dev" file, so just try to run script */
72 /* Determine device name, type, major and minor */
73 device_name = bb_basename(path);
74 /* http://kernel.org/doc/pending/hotplug.txt says that only
75 * "/sys/block/..." is for block devices. "sys/bus" etc is not! */
76 type = (strncmp(&path[5], "block/", 6) == 0 ? S_IFBLK : S_IFCHR);
78 if (ENABLE_FEATURE_MDEV_CONF) {
80 char *line, *val, *next;
83 /* If we have config file, look up user settings */
84 fp = fopen_or_warn("/etc/mdev.conf", "r");
88 while ((line = xmalloc_getline(fp)) != NULL) {
89 regmatch_t off[1+9*ENABLE_FEATURE_MDEV_RENAME_REGEXP];
96 /* Fields: regex uid:gid mode [alias] [cmd] */
98 /* 1st field: regex to match this device */
99 next = next_field(line);
105 xregcomp(&match, line, REG_EXTENDED);
106 result = regexec(&match, device_name, ARRAY_SIZE(off), off, 0);
109 //bb_error_msg("matches:");
110 //for (int i = 0; i < ARRAY_SIZE(off); i++) {
111 // if (off[i].rm_so < 0) continue;
112 // bb_error_msg("match %d: '%.*s'\n", i,
113 // (int)(off[i].rm_eo - off[i].rm_so),
114 // device_name + off[i].rm_so);
117 /* If not this device, skip rest of line */
118 /* (regexec returns whole pattern as "range" 0) */
119 if (result || off[0].rm_so || off[0].rm_eo != strlen(device_name))
123 /* This line matches: stop parsing the file
124 * after parsing the rest of fields */
126 /* 2nd field: uid:gid - device ownership */
127 if (!next) /* field must exist */
128 bb_error_msg_and_die("bad line %u", lineno);
130 next = next_field(val);
135 char *str_gid = strchrnul(val, ':');
140 pass = getpwnam(str_uid);
144 uid = strtoul(str_uid, NULL, 10);
146 grp = getgrnam(str_gid);
150 gid = strtoul(str_gid, NULL, 10);
153 /* 3rd field: mode - device permissions */
154 if (!next) /* field must exist */
155 bb_error_msg_and_die("bad line %u", lineno);
157 next = next_field(val);
158 mode = strtoul(val, NULL, 8);
160 /* 4th field (opt): >alias */
161 if (ENABLE_FEATURE_MDEV_RENAME) {
165 #if ENABLE_FEATURE_MDEV_RENAME_REGEXP
170 next = next_field(val);
171 #if ENABLE_FEATURE_MDEV_RENAME_REGEXP
172 /* substitute %1..9 with off[1..9], if any */
175 while (*s && *s++ == '%')
178 p = alias = xzalloc(strlen(val) + n * strlen(device_name));
184 if (i <= 9 && off[i].rm_so >= 0) {
185 n = off[i].rm_eo - off[i].rm_so;
186 strncpy(p, device_name + off[i].rm_so, n);
195 alias = xstrdup(val + 1);
200 /* The rest (opt): command to run */
204 if (ENABLE_FEATURE_MDEV_EXEC) {
205 const char *s = "@$*";
206 const char *s2 = strchr(s, *val);
209 bb_error_msg_and_die("bad line %u", lineno);
211 /* Correlate the position in the "@$*" with the delete
212 * step so that we get the proper behavior:
213 * @cmd: run on create
214 * $cmd: run on delete
217 if ((s2 - s + 1) /*1/2/3*/ & /*1/2*/ (1 + delete)) {
218 command = xstrdup(val + 1);
221 /* end of field parsing */
222 break; /* we found matching line, stop */
225 } /* end of "while line is read from /etc/mdev.conf" */
227 free(line); /* in case we used "break" to get here */
232 if (!delete && sscanf(dev_maj_min, "%u:%u", &major, &minor) == 2) {
234 if (ENABLE_FEATURE_MDEV_RENAME)
237 if (mknod(device_name, mode | type, makedev(major, minor)) && errno != EEXIST)
238 bb_perror_msg_and_die("mknod %s", device_name);
240 if (major == root_major && minor == root_minor)
241 symlink(device_name, "root");
243 if (ENABLE_FEATURE_MDEV_CONF) {
244 chown(device_name, uid, gid);
246 if (ENABLE_FEATURE_MDEV_RENAME && alias) {
249 /* ">bar/": rename to bar/device_name */
250 /* ">bar[/]baz": rename to bar[/]baz */
251 dest = strrchr(alias, '/');
252 if (dest) { /* ">bar/[baz]" ? */
253 *dest = '\0'; /* mkdir bar */
254 bb_make_directory(alias, 0755, FILEUTILS_RECUR);
256 if (dest[1] == '\0') { /* ">bar/" => ">bar/device_name" */
258 alias = concat_path_file(alias, device_name);
263 /* recreate device_name as a symlink to moved device node */
264 if (rename(device_name, alias) == 0) {
265 symlink(alias, device_name);
273 if (ENABLE_FEATURE_MDEV_EXEC && command) {
274 /* setenv will leak memory, use putenv/unsetenv/free */
275 char *s = xasprintf("MDEV=%s", device_name);
277 if (system(command) == -1)
278 bb_perror_msg_and_die("can't run '%s'", command);
289 /* File callback for /sys/ traversal */
290 static int fileAction(const char *fileName,
291 struct stat *statbuf ATTRIBUTE_UNUSED,
293 int depth ATTRIBUTE_UNUSED)
295 size_t len = strlen(fileName) - 4; /* can't underflow */
296 char *scratch = userData;
298 /* len check is for paranoid reasons */
299 if (strcmp(fileName + len, "/dev") || len >= PATH_MAX)
302 strcpy(scratch, fileName);
304 make_device(scratch, 0);
309 /* Directory callback for /sys/ traversal */
310 static int dirAction(const char *fileName ATTRIBUTE_UNUSED,
311 struct stat *statbuf ATTRIBUTE_UNUSED,
312 void *userData ATTRIBUTE_UNUSED,
315 return (depth >= MAX_SYSFS_DEPTH ? SKIP : TRUE);
318 /* For the full gory details, see linux/Documentation/firmware_class/README
320 * Firmware loading works like this:
321 * - kernel sets FIRMWARE env var
322 * - userspace checks /lib/firmware/$FIRMWARE
323 * - userspace waits for /sys/$DEVPATH/loading to appear
324 * - userspace writes "1" to /sys/$DEVPATH/loading
325 * - userspace copies /lib/firmware/$FIRMWARE into /sys/$DEVPATH/data
326 * - userspace writes "0" (worked) or "-1" (failed) to /sys/$DEVPATH/loading
327 * - kernel loads firmware into device
329 static void load_firmware(const char *const firmware, const char *const sysfs_path)
332 int firmware_fd, loading_fd, data_fd;
334 /* check for /lib/firmware/$FIRMWARE */
335 xchdir("/lib/firmware");
336 firmware_fd = xopen(firmware, O_RDONLY);
338 /* in case we goto out ... */
341 /* check for /sys/$DEVPATH/loading ... give 30 seconds to appear */
343 for (cnt = 0; cnt < 30; ++cnt) {
344 loading_fd = open("loading", O_WRONLY);
345 if (loading_fd != -1)
352 /* tell kernel we're loading by `echo 1 > /sys/$DEVPATH/loading` */
353 if (full_write(loading_fd, "1", 1) != 1)
356 /* load firmware by `cat /lib/firmware/$FIRMWARE > /sys/$DEVPATH/data */
357 data_fd = open("data", O_WRONLY);
360 cnt = bb_copyfd_eof(firmware_fd, data_fd);
362 /* tell kernel result by `echo [0|-1] > /sys/$DEVPATH/loading` */
364 full_write(loading_fd, "0", 1);
366 full_write(loading_fd, "-1", 2);
369 if (ENABLE_FEATURE_CLEAN_UP) {
376 int mdev_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
377 int mdev_main(int argc, char **argv)
381 RESERVE_CONFIG_BUFFER(temp, PATH_MAX + SCRATCH_SIZE);
385 if (argc == 2 && !strcmp(argv[1], "-s")) {
392 root_major = major(st.st_dev);
393 root_minor = minor(st.st_dev);
395 recursive_action("/sys/block",
396 ACTION_RECURSE | ACTION_FOLLOWLINKS,
397 fileAction, dirAction, temp, 0);
399 recursive_action("/sys/class",
400 ACTION_RECURSE | ACTION_FOLLOWLINKS,
401 fileAction, dirAction, temp, 0);
405 * env ACTION=... DEVPATH=... mdev
406 * ACTION can be "add" or "remove"
407 * DEVPATH is like "/block/sda" or "/class/input/mice"
409 action = getenv("ACTION");
410 env_path = getenv("DEVPATH");
411 if (!action || !env_path)
414 snprintf(temp, PATH_MAX, "/sys%s", env_path);
415 if (!strcmp(action, "remove"))
416 make_device(temp, 1);
417 else if (!strcmp(action, "add")) {
418 make_device(temp, 0);
420 if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE) {
421 char *fw = getenv("FIRMWARE");
423 load_firmware(fw, temp);
428 if (ENABLE_FEATURE_CLEAN_UP)
429 RELEASE_CONFIG_BUFFER(temp);