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;
19 #define G (*(struct globals*)&bb_common_bufsiz1)
20 #define root_major (G.root_major)
21 #define root_minor (G.root_minor)
22 #define subsystem (G.subsystem)
24 /* Prevent infinite loops in /sys symlinks */
25 #define MAX_SYSFS_DEPTH 3
27 /* We use additional 64+ bytes in make_device() */
28 #define SCRATCH_SIZE 80
30 #if ENABLE_FEATURE_MDEV_RENAME
31 /* Builds an alias path.
32 * This function potentionally reallocates the alias parameter.
34 static char *build_alias(char *alias, const char *device_name)
38 /* ">bar/": rename to bar/device_name */
39 /* ">bar[/]baz": rename to bar[/]baz */
40 dest = strrchr(alias, '/');
41 if (dest) { /* ">bar/[baz]" ? */
42 *dest = '\0'; /* mkdir bar */
43 bb_make_directory(alias, 0755, FILEUTILS_RECUR);
45 if (dest[1] == '\0') { /* ">bar/" => ">bar/device_name" */
47 alias = concat_path_file(alias, device_name);
56 /* mknod in /dev based on a path like "/sys/block/hda/hda1" */
57 /* NB: "mdev -s" may call us many times, do not leak memory/fds! */
58 static void make_device(char *path, int delete)
60 const char *device_name;
61 int major, minor, type, len;
63 #if ENABLE_FEATURE_MDEV_CONF
64 struct bb_uidgid_t ugid = { 0, 0 };
67 # if ENABLE_FEATURE_MDEV_EXEC
70 # if ENABLE_FEATURE_MDEV_RENAME
72 char aliaslink = aliaslink; /* for compiler */
75 char *dev_maj_min = path + strlen(path);
77 /* Force the configuration file settings exactly. */
80 /* Try to read major/minor string. Note that the kernel puts \n after
81 * the data, so we don't need to worry about null terminating the string
82 * because sscanf() will stop at the first nondigit, which \n is.
83 * We also depend on path having writeable space after it.
87 strcpy(dev_maj_min, "/dev");
88 len = open_read_close(path, dev_maj_min + 1, 64);
89 *dev_maj_min++ = '\0';
91 if (!ENABLE_FEATURE_MDEV_EXEC)
93 /* no "dev" file, so just try to run script */
95 } else if (sscanf(dev_maj_min, "%u:%u", &major, &minor) != 2) {
100 /* Determine device name, type, major and minor */
101 device_name = bb_basename(path);
102 /* http://kernel.org/doc/pending/hotplug.txt says that only
103 * "/sys/block/..." is for block devices. "/sys/bus" etc is not.
104 * But since 2.6.25 block devices are also in /sys/class/block.
105 * We use strstr("/block/") to forestall future surprises. */
107 if (strstr(path, "/block/"))
110 #if ENABLE_FEATURE_MDEV_CONF
111 parser = config_open2("/etc/mdev.conf", fopen_for_read);
113 /* If we have config file, look up user settings */
114 while (config_read(parser, tokens, 4, 3, "# \t", PARSE_NORMAL)) {
115 regmatch_t off[1 + 9*ENABLE_FEATURE_MDEV_RENAME_REGEXP];
116 char *val = tokens[0];
118 /* Fields: regex uid:gid mode [alias] [cmd] */
120 /* 1st field: @<numeric maj,min>... */
121 if (tokens[0][0] == '@') {
122 /* @major,minor[-last] */
123 /* (useful when name is ambiguous:
124 * "/sys/class/usb/lp0" and
125 * "/sys/class/printer/lp0") */
126 int cmaj, cmin0, cmin1, sc;
128 continue; /* no dev, no match */
129 sc = sscanf(tokens[0], "@%u,%u-%u", &cmaj, &cmin0, &cmin1);
130 if (sc < 1 || major != cmaj
131 || (sc == 2 && minor != cmin0)
132 || (sc == 3 && (minor < cmin0 || minor > cmin1))
134 continue; /* no match */
136 } else { /* ... or regex to match device name */
139 const char *dev_name_or_subsystem = device_name;
140 if ('/' == val[0] && subsystem) {
141 dev_name_or_subsystem = subsystem;
146 xregcomp(&match, val, REG_EXTENDED);
147 result = regexec(&match, dev_name_or_subsystem, ARRAY_SIZE(off), off, 0);
150 //bb_error_msg("matches:");
151 //for (int i = 0; i < ARRAY_SIZE(off); i++) {
152 // if (off[i].rm_so < 0) continue;
153 // bb_error_msg("match %d: '%.*s'\n", i,
154 // (int)(off[i].rm_eo - off[i].rm_so),
155 // device_name + off[i].rm_so);
158 /* If not this device, skip rest of line */
159 /* (regexec returns whole pattern as "range" 0) */
160 if (result || off[0].rm_so
161 || ((int)off[0].rm_eo != (int)strlen(dev_name_or_subsystem))
167 /* This line matches: stop parsing the file
168 * after parsing the rest of fields */
170 /* 2nd field: uid:gid - device ownership */
171 parse_chown_usergroup_or_die(&ugid, tokens[1]);
173 /* 3rd field: mode - device permissions */
174 mode = strtoul(tokens[2], NULL, 8);
177 /* 4th field (opt): >alias */
178 # if ENABLE_FEATURE_MDEV_RENAME
182 if (aliaslink == '>' || aliaslink == '=') {
184 # if ENABLE_FEATURE_MDEV_RENAME_REGEXP
189 s = strchrnul(val, ' ');
190 st = strchrnul(val, '\t');
193 val = (s[0] && s[1]) ? s+1 : NULL;
195 # if ENABLE_FEATURE_MDEV_RENAME_REGEXP
196 /* substitute %1..9 with off[1..9], if any */
203 p = alias = xzalloc(strlen(a) + n * strlen(device_name));
209 if (i <= 9 && off[i].rm_so >= 0) {
210 n = off[i].rm_eo - off[i].rm_so;
211 strncpy(p, device_name + off[i].rm_so, n);
220 alias = xstrdup(a + 1);
223 # endif /* ENABLE_FEATURE_MDEV_RENAME */
225 # if ENABLE_FEATURE_MDEV_EXEC
226 /* The rest (opt): command to run */
230 const char *s = "@$*";
231 const char *s2 = strchr(s, *val);
234 bb_error_msg_and_die("bad line %u", parser->lineno);
236 /* Correlate the position in the "@$*" with the delete
237 * step so that we get the proper behavior:
238 * @cmd: run on create
239 * $cmd: run on delete
242 if ((s2 - s + 1) /*1/2/3*/ & /*1/2*/ (1 + delete)) {
243 command = xstrdup(val + 1);
247 /* end of field parsing */
248 break; /* we found matching line, stop */
249 } /* end of "while line is read from /etc/mdev.conf" */
251 config_close(parser);
252 #endif /* ENABLE_FEATURE_MDEV_CONF */
254 if (!delete && major >= 0) {
256 if (ENABLE_FEATURE_MDEV_RENAME)
259 if (mknod(device_name, mode | type, makedev(major, minor)) && errno != EEXIST)
260 bb_perror_msg_and_die("mknod %s", device_name);
262 if (major == root_major && minor == root_minor)
263 symlink(device_name, "root");
265 #if ENABLE_FEATURE_MDEV_CONF
266 chown(device_name, ugid.uid, ugid.gid);
268 # if ENABLE_FEATURE_MDEV_RENAME
270 alias = build_alias(alias, device_name);
272 /* move the device, and optionally
273 * make a symlink to moved device node */
274 if (rename(device_name, alias) == 0 && aliaslink == '>')
275 symlink(alias, device_name);
283 #if ENABLE_FEATURE_MDEV_EXEC
285 /* setenv will leak memory, use putenv/unsetenv/free */
286 char *s = xasprintf("%s=%s", "MDEV", device_name);
287 char *s1 = xasprintf("%s=%s", "SUBSYSTEM", subsystem);
290 if (system(command) == -1)
291 bb_perror_msg_and_die("can't run '%s'", command);
292 unsetenv("SUBSYSTEM");
302 /* At creation time, device might have been moved
303 * and a symlink might have been created. Undo that. */
304 #if ENABLE_FEATURE_MDEV_RENAME
306 alias = build_alias(alias, device_name);
314 /* File callback for /sys/ traversal */
315 static int FAST_FUNC fileAction(const char *fileName,
316 struct stat *statbuf UNUSED_PARAM,
318 int depth UNUSED_PARAM)
320 size_t len = strlen(fileName) - 4; /* can't underflow */
321 char *scratch = userData;
323 /* len check is for paranoid reasons */
324 if (strcmp(fileName + len, "/dev") != 0 || len >= PATH_MAX)
327 strcpy(scratch, fileName);
329 make_device(scratch, 0);
334 /* Directory callback for /sys/ traversal */
335 static int FAST_FUNC dirAction(const char *fileName UNUSED_PARAM,
336 struct stat *statbuf UNUSED_PARAM,
337 void *userData UNUSED_PARAM,
340 /* Extract device subsystem -- the name of the directory under /sys/class/ */
342 subsystem = strrchr(fileName, '/');
347 return (depth >= MAX_SYSFS_DEPTH ? SKIP : TRUE);
350 /* For the full gory details, see linux/Documentation/firmware_class/README
352 * Firmware loading works like this:
353 * - kernel sets FIRMWARE env var
354 * - userspace checks /lib/firmware/$FIRMWARE
355 * - userspace waits for /sys/$DEVPATH/loading to appear
356 * - userspace writes "1" to /sys/$DEVPATH/loading
357 * - userspace copies /lib/firmware/$FIRMWARE into /sys/$DEVPATH/data
358 * - userspace writes "0" (worked) or "-1" (failed) to /sys/$DEVPATH/loading
359 * - kernel loads firmware into device
361 static void load_firmware(const char *const firmware, const char *const sysfs_path)
364 int firmware_fd, loading_fd, data_fd;
366 /* check for /lib/firmware/$FIRMWARE */
367 xchdir("/lib/firmware");
368 firmware_fd = xopen(firmware, O_RDONLY);
370 /* in case we goto out ... */
373 /* check for /sys/$DEVPATH/loading ... give 30 seconds to appear */
375 for (cnt = 0; cnt < 30; ++cnt) {
376 loading_fd = open("loading", O_WRONLY);
377 if (loading_fd != -1)
384 /* tell kernel we're loading by `echo 1 > /sys/$DEVPATH/loading` */
385 if (full_write(loading_fd, "1", 1) != 1)
388 /* load firmware by `cat /lib/firmware/$FIRMWARE > /sys/$DEVPATH/data */
389 data_fd = open("data", O_WRONLY);
392 cnt = bb_copyfd_eof(firmware_fd, data_fd);
394 /* tell kernel result by `echo [0|-1] > /sys/$DEVPATH/loading` */
396 full_write(loading_fd, "0", 1);
398 full_write(loading_fd, "-1", 2);
401 if (ENABLE_FEATURE_CLEAN_UP) {
408 int mdev_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
409 int mdev_main(int argc UNUSED_PARAM, char **argv)
411 RESERVE_CONFIG_BUFFER(temp, PATH_MAX + SCRATCH_SIZE);
413 /* We can be called as hotplug helper */
414 /* Kernel cannot provide suitable stdio fds for us, do it ourself */
419 /* Replace LOGFILE by other file or device name if you need */
420 #define LOGFILE "/dev/console"
421 /* Just making sure fd 0 is not closed,
422 * we don't really intend to read from it */
423 xmove_fd(xopen("/", O_RDONLY), STDIN_FILENO);
424 xmove_fd(xopen(LOGFILE, O_WRONLY|O_APPEND), STDOUT_FILENO);
425 xmove_fd(xopen(LOGFILE, O_WRONLY|O_APPEND), STDERR_FILENO);
430 if (argv[1] && strcmp(argv[1], "-s") == 0) {
437 root_major = major(st.st_dev);
438 root_minor = minor(st.st_dev);
440 /* ACTION_FOLLOWLINKS is needed since in newer kernels
441 * /sys/block/loop* (for example) are symlinks to dirs,
442 * not real directories.
443 * (kernel's CONFIG_SYSFS_DEPRECATED makes them real dirs,
444 * but we can't enforce that on users)
446 if (access("/sys/class/block", F_OK) != 0) {
447 /* Scan obsolete /sys/block only if /sys/class/block
448 * doesn't exist. Otherwise we'll have dupes.
449 * Also, do not complain if it doesn't exist.
450 * Some people configure kernel to have no blockdevs.
452 recursive_action("/sys/block",
453 ACTION_RECURSE | ACTION_FOLLOWLINKS | ACTION_QUIET,
454 fileAction, dirAction, temp, 0);
456 recursive_action("/sys/class",
457 ACTION_RECURSE | ACTION_FOLLOWLINKS,
458 fileAction, dirAction, temp, 0);
466 * env ACTION=... DEVPATH=... SUBSYSTEM=... [SEQNUM=...] mdev
467 * ACTION can be "add" or "remove"
468 * DEVPATH is like "/block/sda" or "/class/input/mice"
470 action = getenv("ACTION");
471 env_path = getenv("DEVPATH");
472 subsystem = getenv("SUBSYSTEM");
473 if (!action || !env_path /*|| !subsystem*/)
475 fw = getenv("FIRMWARE");
477 /* If it exists, does /dev/mdev.seq match $SEQNUM?
478 * If it does not match, earlier mdev is running
479 * in parallel, and we need to wait */
480 seq = getenv("SEQNUM");
482 int timeout = 2000 / 32; /* 2000 msec */
485 char seqbuf[sizeof(int)*3 + 2];
487 seqlen = open_read_close("mdev.seq", seqbuf, sizeof(seqbuf-1));
492 seqbuf[seqlen] = '\0';
493 if (seqbuf[0] == '\n' /* seed file? */
494 || strcmp(seq, seqbuf) == 0 /* correct idx? */
502 snprintf(temp, PATH_MAX, "/sys%s", env_path);
503 if (strcmp(action, "remove") == 0) {
504 /* Ignoring "remove firmware". It was reported
505 * to happen and to cause erroneous deletion
506 * of device nodes. */
508 make_device(temp, 1);
510 else if (strcmp(action, "add") == 0) {
511 make_device(temp, 0);
512 if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE) {
514 load_firmware(fw, temp);
519 xopen_xwrite_close("mdev.seq", utoa(xatou(seq) + 1));
523 if (ENABLE_FEATURE_CLEAN_UP)
524 RELEASE_CONFIG_BUFFER(temp);