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);
50 /* Force the configuration file settings exactly. */
53 /* Try to read major/minor string. Note that the kernel puts \n after
54 * the data, so we don't need to worry about null terminating the string
55 * because sscanf() will stop at the first nondigit, which \n is. We
56 * also depend on path having writeable space after it.
59 strcpy(dev_maj_min, "/dev");
60 len = open_read_close(path, dev_maj_min + 1, 64);
61 *dev_maj_min++ = '\0';
63 if (!ENABLE_FEATURE_MDEV_EXEC)
65 /* no "dev" file, so just try to run script */
70 /* Determine device name, type, major and minor */
71 device_name = bb_basename(path);
72 /* http://kernel.org/doc/pending/hotplug.txt says that only
73 * "/sys/block/..." is for block devices. "/sys/bus" etc is not!
74 * Since kernel 2.6.25 block devices are also in /sys/class/block. */
75 /* TODO: would it be acceptable to just use strstr(path, "/block/")? */
76 if (strncmp(&path[5], "class/block/"+6, 6) != 0
77 && strncmp(&path[5], "class/block/", 12) != 0)
82 if (ENABLE_FEATURE_MDEV_CONF) {
84 char *line, *val, *next;
87 /* If we have config file, look up user settings */
88 fp = fopen_or_warn("/etc/mdev.conf", "r");
92 while ((line = xmalloc_fgetline(fp)) != NULL) {
93 regmatch_t off[1+9*ENABLE_FEATURE_MDEV_RENAME_REGEXP];
100 /* Fields: regex uid:gid mode [alias] [cmd] */
102 /* 1st field: regex to match this device */
103 next = next_field(line);
109 xregcomp(&match, line, REG_EXTENDED);
110 result = regexec(&match, device_name, ARRAY_SIZE(off), off, 0);
113 //bb_error_msg("matches:");
114 //for (int i = 0; i < ARRAY_SIZE(off); i++) {
115 // if (off[i].rm_so < 0) continue;
116 // bb_error_msg("match %d: '%.*s'\n", i,
117 // (int)(off[i].rm_eo - off[i].rm_so),
118 // device_name + off[i].rm_so);
121 /* If not this device, skip rest of line */
122 /* (regexec returns whole pattern as "range" 0) */
123 if (result || off[0].rm_so || off[0].rm_eo != strlen(device_name))
127 /* This line matches: stop parsing the file
128 * after parsing the rest of fields */
130 /* 2nd field: uid:gid - device ownership */
131 if (!next) /* field must exist */
132 bb_error_msg_and_die("bad line %u", lineno);
134 next = next_field(val);
139 char *str_gid = strchrnul(val, ':');
144 pass = getpwnam(str_uid);
148 uid = strtoul(str_uid, NULL, 10);
150 grp = getgrnam(str_gid);
154 gid = strtoul(str_gid, NULL, 10);
157 /* 3rd field: mode - device permissions */
158 if (!next) /* field must exist */
159 bb_error_msg_and_die("bad line %u", lineno);
161 next = next_field(val);
162 mode = strtoul(val, NULL, 8);
164 /* 4th field (opt): >alias */
165 #if ENABLE_FEATURE_MDEV_RENAME
169 #if ENABLE_FEATURE_MDEV_RENAME_REGEXP
174 next = next_field(val);
175 /* substitute %1..9 with off[1..9], if any */
178 while (*s && *s++ == '%')
181 p = alias = xzalloc(strlen(val) + n * strlen(device_name));
187 if (i <= 9 && off[i].rm_so >= 0) {
188 n = off[i].rm_eo - off[i].rm_so;
189 strncpy(p, device_name + off[i].rm_so, n);
199 next = next_field(val);
200 alias = xstrdup(val + 1);
203 #endif /* ENABLE_FEATURE_MDEV_RENAME */
205 /* The rest (opt): command to run */
209 if (ENABLE_FEATURE_MDEV_EXEC) {
210 const char *s = "@$*";
211 const char *s2 = strchr(s, *val);
214 bb_error_msg_and_die("bad line %u", lineno);
216 /* Correlate the position in the "@$*" with the delete
217 * step so that we get the proper behavior:
218 * @cmd: run on create
219 * $cmd: run on delete
222 if ((s2 - s + 1) /*1/2/3*/ & /*1/2*/ (1 + delete)) {
223 command = xstrdup(val + 1);
226 /* end of field parsing */
227 break; /* we found matching line, stop */
230 } /* end of "while line is read from /etc/mdev.conf" */
232 free(line); /* in case we used "break" to get here */
237 if (!delete && sscanf(dev_maj_min, "%u:%u", &major, &minor) == 2) {
239 if (ENABLE_FEATURE_MDEV_RENAME)
242 if (mknod(device_name, mode | type, makedev(major, minor)) && errno != EEXIST)
243 bb_perror_msg_and_die("mknod %s", device_name);
245 if (major == root_major && minor == root_minor)
246 symlink(device_name, "root");
248 if (ENABLE_FEATURE_MDEV_CONF) {
249 chown(device_name, uid, gid);
251 if (ENABLE_FEATURE_MDEV_RENAME && alias) {
254 /* ">bar/": rename to bar/device_name */
255 /* ">bar[/]baz": rename to bar[/]baz */
256 dest = strrchr(alias, '/');
257 if (dest) { /* ">bar/[baz]" ? */
258 *dest = '\0'; /* mkdir bar */
259 bb_make_directory(alias, 0755, FILEUTILS_RECUR);
261 if (dest[1] == '\0') { /* ">bar/" => ">bar/device_name" */
263 alias = concat_path_file(alias, device_name);
268 /* recreate device_name as a symlink to moved device node */
269 if (rename(device_name, alias) == 0) {
270 symlink(alias, device_name);
278 if (ENABLE_FEATURE_MDEV_EXEC && command) {
279 /* setenv will leak memory, use putenv/unsetenv/free */
280 char *s = xasprintf("MDEV=%s", device_name);
282 if (system(command) == -1)
283 bb_perror_msg_and_die("can't run '%s'", command);
294 /* File callback for /sys/ traversal */
295 static int fileAction(const char *fileName,
296 struct stat *statbuf ATTRIBUTE_UNUSED,
298 int depth ATTRIBUTE_UNUSED)
300 size_t len = strlen(fileName) - 4; /* can't underflow */
301 char *scratch = userData;
303 /* len check is for paranoid reasons */
304 if (strcmp(fileName + len, "/dev") || len >= PATH_MAX)
307 strcpy(scratch, fileName);
309 make_device(scratch, 0);
314 /* Directory callback for /sys/ traversal */
315 static int dirAction(const char *fileName ATTRIBUTE_UNUSED,
316 struct stat *statbuf ATTRIBUTE_UNUSED,
317 void *userData ATTRIBUTE_UNUSED,
320 return (depth >= MAX_SYSFS_DEPTH ? SKIP : TRUE);
323 /* For the full gory details, see linux/Documentation/firmware_class/README
325 * Firmware loading works like this:
326 * - kernel sets FIRMWARE env var
327 * - userspace checks /lib/firmware/$FIRMWARE
328 * - userspace waits for /sys/$DEVPATH/loading to appear
329 * - userspace writes "1" to /sys/$DEVPATH/loading
330 * - userspace copies /lib/firmware/$FIRMWARE into /sys/$DEVPATH/data
331 * - userspace writes "0" (worked) or "-1" (failed) to /sys/$DEVPATH/loading
332 * - kernel loads firmware into device
334 static void load_firmware(const char *const firmware, const char *const sysfs_path)
337 int firmware_fd, loading_fd, data_fd;
339 /* check for /lib/firmware/$FIRMWARE */
340 xchdir("/lib/firmware");
341 firmware_fd = xopen(firmware, O_RDONLY);
343 /* in case we goto out ... */
346 /* check for /sys/$DEVPATH/loading ... give 30 seconds to appear */
348 for (cnt = 0; cnt < 30; ++cnt) {
349 loading_fd = open("loading", O_WRONLY);
350 if (loading_fd != -1)
357 /* tell kernel we're loading by `echo 1 > /sys/$DEVPATH/loading` */
358 if (full_write(loading_fd, "1", 1) != 1)
361 /* load firmware by `cat /lib/firmware/$FIRMWARE > /sys/$DEVPATH/data */
362 data_fd = open("data", O_WRONLY);
365 cnt = bb_copyfd_eof(firmware_fd, data_fd);
367 /* tell kernel result by `echo [0|-1] > /sys/$DEVPATH/loading` */
369 full_write(loading_fd, "0", 1);
371 full_write(loading_fd, "-1", 2);
374 if (ENABLE_FEATURE_CLEAN_UP) {
381 int mdev_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
382 int mdev_main(int argc, char **argv)
386 RESERVE_CONFIG_BUFFER(temp, PATH_MAX + SCRATCH_SIZE);
390 if (argc == 2 && !strcmp(argv[1], "-s")) {
397 root_major = major(st.st_dev);
398 root_minor = minor(st.st_dev);
400 recursive_action("/sys/block",
401 ACTION_RECURSE | ACTION_FOLLOWLINKS,
402 fileAction, dirAction, temp, 0);
404 recursive_action("/sys/class",
405 ACTION_RECURSE | ACTION_FOLLOWLINKS,
406 fileAction, dirAction, temp, 0);
410 * env ACTION=... DEVPATH=... mdev
411 * ACTION can be "add" or "remove"
412 * DEVPATH is like "/block/sda" or "/class/input/mice"
414 action = getenv("ACTION");
415 env_path = getenv("DEVPATH");
416 if (!action || !env_path)
419 snprintf(temp, PATH_MAX, "/sys%s", env_path);
420 if (!strcmp(action, "remove"))
421 make_device(temp, 1);
422 else if (!strcmp(action, "add")) {
423 make_device(temp, 0);
425 if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE) {
426 char *fw = getenv("FIRMWARE");
428 load_firmware(fw, temp);
433 if (ENABLE_FEATURE_CLEAN_UP)
434 RELEASE_CONFIG_BUFFER(temp);