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.
16 int root_major, root_minor;
18 #define G (*(struct globals*)&bb_common_bufsiz1)
19 #define root_major (G.root_major)
20 #define root_minor (G.root_minor)
22 /* Prevent infinite loops in /sys symlinks */
23 #define MAX_SYSFS_DEPTH 3
25 /* We use additional 64+ bytes in make_device() */
26 #define SCRATCH_SIZE 80
28 static char *next_field(char *s)
30 char *end = skip_non_whitespace(s);
31 s = skip_whitespace(end);
38 /* mknod in /dev based on a path like "/sys/block/hda/hda1" */
39 /* NB: "mdev -s" may call us many times, do not leak memory/fds! */
40 static void make_device(char *path, int delete)
42 const char *device_name;
43 int major, minor, type, len;
47 char *dev_maj_min = path + strlen(path);
50 char aliaslink = aliaslink; /* for compiler */
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 * Since kernel 2.6.25 block devices are also in /sys/class/block. */
77 /* TODO: would it be acceptable to just use strstr(path, "/block/")? */
78 if (strncmp(&path[5], "class/block/"+6, 6) != 0
79 && strncmp(&path[5], "class/block/", 12) != 0)
84 if (ENABLE_FEATURE_MDEV_CONF) {
86 char *line, *val, *next;
89 /* If we have config file, look up user settings */
90 fp = fopen_or_warn("/etc/mdev.conf", "r");
94 while ((line = xmalloc_fgetline(fp)) != NULL) {
95 regmatch_t off[1+9*ENABLE_FEATURE_MDEV_RENAME_REGEXP];
102 /* Fields: regex uid:gid mode [alias] [cmd] */
104 /* 1st field: regex to match this device */
105 next = next_field(line);
111 xregcomp(&match, line, REG_EXTENDED);
112 result = regexec(&match, device_name, ARRAY_SIZE(off), off, 0);
115 //bb_error_msg("matches:");
116 //for (int i = 0; i < ARRAY_SIZE(off); i++) {
117 // if (off[i].rm_so < 0) continue;
118 // bb_error_msg("match %d: '%.*s'\n", i,
119 // (int)(off[i].rm_eo - off[i].rm_so),
120 // device_name + off[i].rm_so);
123 /* If not this device, skip rest of line */
124 /* (regexec returns whole pattern as "range" 0) */
125 if (result || off[0].rm_so
126 || ((int)off[0].rm_eo != (int)strlen(device_name))
132 /* This line matches: stop parsing the file
133 * after parsing the rest of fields */
135 /* 2nd field: uid:gid - device ownership */
136 if (!next) /* field must exist */
137 bb_error_msg_and_die("bad line %u", lineno);
139 next = next_field(val);
144 char *str_gid = strchrnul(val, ':');
149 pass = getpwnam(str_uid);
153 uid = strtoul(str_uid, NULL, 10);
155 grp = getgrnam(str_gid);
159 gid = strtoul(str_gid, NULL, 10);
162 /* 3rd field: mode - device permissions */
163 if (!next) /* field must exist */
164 bb_error_msg_and_die("bad line %u", lineno);
166 next = next_field(val);
167 mode = strtoul(val, NULL, 8);
169 /* 4th field (opt): >alias */
170 #if ENABLE_FEATURE_MDEV_RENAME
173 if (*next == '>' || *next == '=') {
174 #if ENABLE_FEATURE_MDEV_RENAME_REGEXP
180 next = next_field(val);
181 /* substitute %1..9 with off[1..9], if any */
188 p = alias = xzalloc(strlen(val) + n * strlen(device_name));
194 if (i <= 9 && off[i].rm_so >= 0) {
195 n = off[i].rm_eo - off[i].rm_so;
196 strncpy(p, device_name + off[i].rm_so, n);
207 next = next_field(val);
208 alias = xstrdup(val + 1);
211 #endif /* ENABLE_FEATURE_MDEV_RENAME */
213 /* The rest (opt): command to run */
217 if (ENABLE_FEATURE_MDEV_EXEC) {
218 const char *s = "@$*";
219 const char *s2 = strchr(s, *val);
222 bb_error_msg_and_die("bad line %u", lineno);
224 /* Correlate the position in the "@$*" with the delete
225 * step so that we get the proper behavior:
226 * @cmd: run on create
227 * $cmd: run on delete
230 if ((s2 - s + 1) /*1/2/3*/ & /*1/2*/ (1 + delete)) {
231 command = xstrdup(val + 1);
234 /* end of field parsing */
235 break; /* we found matching line, stop */
238 } /* end of "while line is read from /etc/mdev.conf" */
240 free(line); /* in case we used "break" to get here */
245 if (!delete && sscanf(dev_maj_min, "%u:%u", &major, &minor) == 2) {
247 if (ENABLE_FEATURE_MDEV_RENAME)
250 if (mknod(device_name, mode | type, makedev(major, minor)) && errno != EEXIST)
251 bb_perror_msg_and_die("mknod %s", device_name);
253 if (major == root_major && minor == root_minor)
254 symlink(device_name, "root");
256 if (ENABLE_FEATURE_MDEV_CONF) {
257 chown(device_name, uid, gid);
259 if (ENABLE_FEATURE_MDEV_RENAME && alias) {
262 /* ">bar/": rename to bar/device_name */
263 /* ">bar[/]baz": rename to bar[/]baz */
264 dest = strrchr(alias, '/');
265 if (dest) { /* ">bar/[baz]" ? */
266 *dest = '\0'; /* mkdir bar */
267 bb_make_directory(alias, 0755, FILEUTILS_RECUR);
269 if (dest[1] == '\0') { /* ">bar/" => ">bar/device_name" */
271 alias = concat_path_file(alias, device_name);
276 /* move the device, and optionally
277 * make a symlink to moved device node */
278 if (rename(device_name, alias) == 0 && aliaslink == '>')
279 symlink(alias, device_name);
286 if (ENABLE_FEATURE_MDEV_EXEC && command) {
287 /* setenv will leak memory, use putenv/unsetenv/free */
288 char *s = xasprintf("MDEV=%s", device_name);
290 if (system(command) == -1)
291 bb_perror_msg_and_die("can't run '%s'", command);
302 /* File callback for /sys/ traversal */
303 static int FAST_FUNC fileAction(const char *fileName,
304 struct stat *statbuf UNUSED_PARAM,
306 int depth UNUSED_PARAM)
308 size_t len = strlen(fileName) - 4; /* can't underflow */
309 char *scratch = userData;
311 /* len check is for paranoid reasons */
312 if (strcmp(fileName + len, "/dev") || len >= PATH_MAX)
315 strcpy(scratch, fileName);
317 make_device(scratch, 0);
322 /* Directory callback for /sys/ traversal */
323 static int FAST_FUNC dirAction(const char *fileName UNUSED_PARAM,
324 struct stat *statbuf UNUSED_PARAM,
325 void *userData UNUSED_PARAM,
328 return (depth >= MAX_SYSFS_DEPTH ? SKIP : TRUE);
331 /* For the full gory details, see linux/Documentation/firmware_class/README
333 * Firmware loading works like this:
334 * - kernel sets FIRMWARE env var
335 * - userspace checks /lib/firmware/$FIRMWARE
336 * - userspace waits for /sys/$DEVPATH/loading to appear
337 * - userspace writes "1" to /sys/$DEVPATH/loading
338 * - userspace copies /lib/firmware/$FIRMWARE into /sys/$DEVPATH/data
339 * - userspace writes "0" (worked) or "-1" (failed) to /sys/$DEVPATH/loading
340 * - kernel loads firmware into device
342 static void load_firmware(const char *const firmware, const char *const sysfs_path)
345 int firmware_fd, loading_fd, data_fd;
347 /* check for /lib/firmware/$FIRMWARE */
348 xchdir("/lib/firmware");
349 firmware_fd = xopen(firmware, O_RDONLY);
351 /* in case we goto out ... */
354 /* check for /sys/$DEVPATH/loading ... give 30 seconds to appear */
356 for (cnt = 0; cnt < 30; ++cnt) {
357 loading_fd = open("loading", O_WRONLY);
358 if (loading_fd != -1)
365 /* tell kernel we're loading by `echo 1 > /sys/$DEVPATH/loading` */
366 if (full_write(loading_fd, "1", 1) != 1)
369 /* load firmware by `cat /lib/firmware/$FIRMWARE > /sys/$DEVPATH/data */
370 data_fd = open("data", O_WRONLY);
373 cnt = bb_copyfd_eof(firmware_fd, data_fd);
375 /* tell kernel result by `echo [0|-1] > /sys/$DEVPATH/loading` */
377 full_write(loading_fd, "0", 1);
379 full_write(loading_fd, "-1", 2);
382 if (ENABLE_FEATURE_CLEAN_UP) {
389 int mdev_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
390 int mdev_main(int argc, char **argv)
394 RESERVE_CONFIG_BUFFER(temp, PATH_MAX + SCRATCH_SIZE);
396 /* We can be called as hotplug helper */
397 /* Kernel cannot provide suitable stdio fds for us, do it ourself */
402 /* Replace LOGFILE by other file or device name if you need */
403 #define LOGFILE "/dev/console"
404 /* Just making sure fd 0 is not closed,
405 * we don't really intend to read from it */
406 xmove_fd(xopen("/", O_RDONLY), STDIN_FILENO);
407 xmove_fd(xopen(LOGFILE, O_WRONLY|O_APPEND), STDOUT_FILENO);
408 xmove_fd(xopen(LOGFILE, O_WRONLY|O_APPEND), STDERR_FILENO);
413 if (argc == 2 && !strcmp(argv[1], "-s")) {
420 root_major = major(st.st_dev);
421 root_minor = minor(st.st_dev);
423 /* ACTION_FOLLOWLINKS is needed since in newer kernels
424 * /sys/block/loop* (for example) are symlinks to dirs,
425 * not real directories.
426 * (kernel's CONFIG_SYSFS_DEPRECATED makes them real dirs,
427 * but we can't enforce that on users) */
428 recursive_action("/sys/block",
429 ACTION_RECURSE | ACTION_FOLLOWLINKS,
430 fileAction, dirAction, temp, 0);
431 recursive_action("/sys/class",
432 ACTION_RECURSE | ACTION_FOLLOWLINKS,
433 fileAction, dirAction, temp, 0);
436 * env ACTION=... DEVPATH=... mdev
437 * ACTION can be "add" or "remove"
438 * DEVPATH is like "/block/sda" or "/class/input/mice"
440 action = getenv("ACTION");
441 env_path = getenv("DEVPATH");
442 if (!action || !env_path)
445 snprintf(temp, PATH_MAX, "/sys%s", env_path);
446 if (!strcmp(action, "remove"))
447 make_device(temp, 1);
448 else if (!strcmp(action, "add")) {
449 make_device(temp, 0);
451 if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE) {
452 char *fw = getenv("FIRMWARE");
454 load_firmware(fw, temp);
459 if (ENABLE_FEATURE_CLEAN_UP)
460 RELEASE_CONFIG_BUFFER(temp);