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 #define MAX_SYSFS_DEPTH 3 /* prevent infinite loops in /sys symlinks */
24 /* We use additional 64+ bytes in make_device() */
25 #define SCRATCH_SIZE 80
27 static char *next_field(char *s)
29 char *end = skip_non_whitespace(s);
30 s = skip_whitespace(end);
37 /* mknod in /dev based on a path like "/sys/block/hda/hda1" */
38 /* NB: "mdev -s" may call us many times, do not leak memory/fds! */
39 static void make_device(char *path, int delete)
41 const char *device_name;
42 int major, minor, type, len;
46 char *dev_maj_min = path + strlen(path);
49 char aliaslink = aliaslink; /* for compiler */
51 /* Force the configuration file settings exactly. */
54 /* Try to read major/minor string. Note that the kernel puts \n after
55 * the data, so we don't need to worry about null terminating the string
56 * because sscanf() will stop at the first nondigit, which \n is. We
57 * also depend on path having writeable space after it.
60 strcpy(dev_maj_min, "/dev");
61 len = open_read_close(path, dev_maj_min + 1, 64);
62 *dev_maj_min++ = '\0';
64 if (!ENABLE_FEATURE_MDEV_EXEC)
66 /* no "dev" file, so just try to run script */
71 /* Determine device name, type, major and minor */
72 device_name = bb_basename(path);
73 /* http://kernel.org/doc/pending/hotplug.txt says that only
74 * "/sys/block/..." is for block devices. "/sys/bus" etc is not!
75 * Since kernel 2.6.25 block devices are also in /sys/class/block. */
76 /* TODO: would it be acceptable to just use strstr(path, "/block/")? */
77 if (strncmp(&path[5], "class/block/"+6, 6) != 0
78 && strncmp(&path[5], "class/block/", 12) != 0)
83 if (ENABLE_FEATURE_MDEV_CONF) {
85 char *line, *val, *next;
88 /* If we have config file, look up user settings */
89 fp = fopen_or_warn("/etc/mdev.conf", "r");
93 while ((line = xmalloc_fgetline(fp)) != NULL) {
94 regmatch_t off[1+9*ENABLE_FEATURE_MDEV_RENAME_REGEXP];
101 /* Fields: regex uid:gid mode [alias] [cmd] */
103 /* 1st field: regex to match this device */
104 next = next_field(line);
110 xregcomp(&match, line, REG_EXTENDED);
111 result = regexec(&match, device_name, ARRAY_SIZE(off), off, 0);
114 //bb_error_msg("matches:");
115 //for (int i = 0; i < ARRAY_SIZE(off); i++) {
116 // if (off[i].rm_so < 0) continue;
117 // bb_error_msg("match %d: '%.*s'\n", i,
118 // (int)(off[i].rm_eo - off[i].rm_so),
119 // device_name + off[i].rm_so);
122 /* If not this device, skip rest of line */
123 /* (regexec returns whole pattern as "range" 0) */
124 if (result || off[0].rm_so
125 || ((int)off[0].rm_eo != (int)strlen(device_name))
131 /* This line matches: stop parsing the file
132 * after parsing the rest of fields */
134 /* 2nd field: uid:gid - device ownership */
135 if (!next) /* field must exist */
136 bb_error_msg_and_die("bad line %u", lineno);
138 next = next_field(val);
143 char *str_gid = strchrnul(val, ':');
148 pass = getpwnam(str_uid);
152 uid = strtoul(str_uid, NULL, 10);
154 grp = getgrnam(str_gid);
158 gid = strtoul(str_gid, NULL, 10);
161 /* 3rd field: mode - device permissions */
162 if (!next) /* field must exist */
163 bb_error_msg_and_die("bad line %u", lineno);
165 next = next_field(val);
166 mode = strtoul(val, NULL, 8);
168 /* 4th field (opt): >alias */
169 #if ENABLE_FEATURE_MDEV_RENAME
172 if (*next == '>' || *next == '=') {
173 #if ENABLE_FEATURE_MDEV_RENAME_REGEXP
179 next = next_field(val);
180 /* substitute %1..9 with off[1..9], if any */
183 while (*s && *s++ == '%')
186 p = alias = xzalloc(strlen(val) + n * strlen(device_name));
192 if (i <= 9 && off[i].rm_so >= 0) {
193 n = off[i].rm_eo - off[i].rm_so;
194 strncpy(p, device_name + off[i].rm_so, n);
205 next = next_field(val);
206 alias = xstrdup(val + 1);
209 #endif /* ENABLE_FEATURE_MDEV_RENAME */
211 /* The rest (opt): command to run */
215 if (ENABLE_FEATURE_MDEV_EXEC) {
216 const char *s = "@$*";
217 const char *s2 = strchr(s, *val);
220 bb_error_msg_and_die("bad line %u", lineno);
222 /* Correlate the position in the "@$*" with the delete
223 * step so that we get the proper behavior:
224 * @cmd: run on create
225 * $cmd: run on delete
228 if ((s2 - s + 1) /*1/2/3*/ & /*1/2*/ (1 + delete)) {
229 command = xstrdup(val + 1);
232 /* end of field parsing */
233 break; /* we found matching line, stop */
236 } /* end of "while line is read from /etc/mdev.conf" */
238 free(line); /* in case we used "break" to get here */
243 if (!delete && sscanf(dev_maj_min, "%u:%u", &major, &minor) == 2) {
245 if (ENABLE_FEATURE_MDEV_RENAME)
248 if (mknod(device_name, mode | type, makedev(major, minor)) && errno != EEXIST)
249 bb_perror_msg_and_die("mknod %s", device_name);
251 if (major == root_major && minor == root_minor)
252 symlink(device_name, "root");
254 if (ENABLE_FEATURE_MDEV_CONF) {
255 chown(device_name, uid, gid);
257 if (ENABLE_FEATURE_MDEV_RENAME && alias) {
260 /* ">bar/": rename to bar/device_name */
261 /* ">bar[/]baz": rename to bar[/]baz */
262 dest = strrchr(alias, '/');
263 if (dest) { /* ">bar/[baz]" ? */
264 *dest = '\0'; /* mkdir bar */
265 bb_make_directory(alias, 0755, FILEUTILS_RECUR);
267 if (dest[1] == '\0') { /* ">bar/" => ">bar/device_name" */
269 alias = concat_path_file(alias, device_name);
274 /* move the device, and optionally
275 * make a symlink to moved device node */
276 if (rename(device_name, alias) == 0 && aliaslink == '>')
277 symlink(alias, device_name);
284 if (ENABLE_FEATURE_MDEV_EXEC && command) {
285 /* setenv will leak memory, use putenv/unsetenv/free */
286 char *s = xasprintf("MDEV=%s", device_name);
288 if (system(command) == -1)
289 bb_perror_msg_and_die("can't run '%s'", command);
300 /* File callback for /sys/ traversal */
301 static int fileAction(const char *fileName,
302 struct stat *statbuf ATTRIBUTE_UNUSED,
304 int depth ATTRIBUTE_UNUSED)
306 size_t len = strlen(fileName) - 4; /* can't underflow */
307 char *scratch = userData;
309 /* len check is for paranoid reasons */
310 if (strcmp(fileName + len, "/dev") || len >= PATH_MAX)
313 strcpy(scratch, fileName);
315 make_device(scratch, 0);
320 /* Directory callback for /sys/ traversal */
321 static int dirAction(const char *fileName ATTRIBUTE_UNUSED,
322 struct stat *statbuf ATTRIBUTE_UNUSED,
323 void *userData ATTRIBUTE_UNUSED,
326 return (depth >= MAX_SYSFS_DEPTH ? SKIP : TRUE);
329 /* For the full gory details, see linux/Documentation/firmware_class/README
331 * Firmware loading works like this:
332 * - kernel sets FIRMWARE env var
333 * - userspace checks /lib/firmware/$FIRMWARE
334 * - userspace waits for /sys/$DEVPATH/loading to appear
335 * - userspace writes "1" to /sys/$DEVPATH/loading
336 * - userspace copies /lib/firmware/$FIRMWARE into /sys/$DEVPATH/data
337 * - userspace writes "0" (worked) or "-1" (failed) to /sys/$DEVPATH/loading
338 * - kernel loads firmware into device
340 static void load_firmware(const char *const firmware, const char *const sysfs_path)
343 int firmware_fd, loading_fd, data_fd;
345 /* check for /lib/firmware/$FIRMWARE */
346 xchdir("/lib/firmware");
347 firmware_fd = xopen(firmware, O_RDONLY);
349 /* in case we goto out ... */
352 /* check for /sys/$DEVPATH/loading ... give 30 seconds to appear */
354 for (cnt = 0; cnt < 30; ++cnt) {
355 loading_fd = open("loading", O_WRONLY);
356 if (loading_fd != -1)
363 /* tell kernel we're loading by `echo 1 > /sys/$DEVPATH/loading` */
364 if (full_write(loading_fd, "1", 1) != 1)
367 /* load firmware by `cat /lib/firmware/$FIRMWARE > /sys/$DEVPATH/data */
368 data_fd = open("data", O_WRONLY);
371 cnt = bb_copyfd_eof(firmware_fd, data_fd);
373 /* tell kernel result by `echo [0|-1] > /sys/$DEVPATH/loading` */
375 full_write(loading_fd, "0", 1);
377 full_write(loading_fd, "-1", 2);
380 if (ENABLE_FEATURE_CLEAN_UP) {
387 int mdev_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
388 int mdev_main(int argc, char **argv)
392 RESERVE_CONFIG_BUFFER(temp, PATH_MAX + SCRATCH_SIZE);
396 if (argc == 2 && !strcmp(argv[1], "-s")) {
403 root_major = major(st.st_dev);
404 root_minor = minor(st.st_dev);
406 recursive_action("/sys/block",
407 ACTION_RECURSE | ACTION_FOLLOWLINKS,
408 fileAction, dirAction, temp, 0);
410 recursive_action("/sys/class",
411 ACTION_RECURSE | ACTION_FOLLOWLINKS,
412 fileAction, dirAction, temp, 0);
416 * env ACTION=... DEVPATH=... mdev
417 * ACTION can be "add" or "remove"
418 * DEVPATH is like "/block/sda" or "/class/input/mice"
420 action = getenv("ACTION");
421 env_path = getenv("DEVPATH");
422 if (!action || !env_path)
425 snprintf(temp, PATH_MAX, "/sys%s", env_path);
426 if (!strcmp(action, "remove"))
427 make_device(temp, 1);
428 else if (!strcmp(action, "add")) {
429 make_device(temp, 0);
431 if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE) {
432 char *fw = getenv("FIRMWARE");
434 load_firmware(fw, temp);
439 if (ENABLE_FEATURE_CLEAN_UP)
440 RELEASE_CONFIG_BUFFER(temp);