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 type = (strncmp(&path[5], "block/", 6) == 0 ? S_IFBLK : S_IFCHR);
76 if (ENABLE_FEATURE_MDEV_CONF) {
78 char *line, *val, *next;
81 /* If we have config file, look up user settings */
82 fp = fopen_or_warn("/etc/mdev.conf", "r");
86 while ((line = xmalloc_fgetline(fp)) != NULL) {
87 regmatch_t off[1+9*ENABLE_FEATURE_MDEV_RENAME_REGEXP];
94 /* Fields: regex uid:gid mode [alias] [cmd] */
96 /* 1st field: regex to match this device */
97 next = next_field(line);
103 xregcomp(&match, line, REG_EXTENDED);
104 result = regexec(&match, device_name, ARRAY_SIZE(off), off, 0);
107 //bb_error_msg("matches:");
108 //for (int i = 0; i < ARRAY_SIZE(off); i++) {
109 // if (off[i].rm_so < 0) continue;
110 // bb_error_msg("match %d: '%.*s'\n", i,
111 // (int)(off[i].rm_eo - off[i].rm_so),
112 // device_name + off[i].rm_so);
115 /* If not this device, skip rest of line */
116 /* (regexec returns whole pattern as "range" 0) */
117 if (result || off[0].rm_so || off[0].rm_eo != strlen(device_name))
121 /* This line matches: stop parsing the file
122 * after parsing the rest of fields */
124 /* 2nd field: uid:gid - device ownership */
125 if (!next) /* field must exist */
126 bb_error_msg_and_die("bad line %u", lineno);
128 next = next_field(val);
133 char *str_gid = strchrnul(val, ':');
138 pass = getpwnam(str_uid);
142 uid = strtoul(str_uid, NULL, 10);
144 grp = getgrnam(str_gid);
148 gid = strtoul(str_gid, NULL, 10);
151 /* 3rd field: mode - device permissions */
152 if (!next) /* field must exist */
153 bb_error_msg_and_die("bad line %u", lineno);
155 next = next_field(val);
156 mode = strtoul(val, NULL, 8);
158 /* 4th field (opt): >alias */
159 if (ENABLE_FEATURE_MDEV_RENAME) {
163 next = next_field(val);
165 #if ENABLE_FEATURE_MDEV_RENAME_REGEXP
166 /* substitute %1..9 with off[1..9], if any */
172 while (*s && *s++ == '%')
175 p = alias = xzalloc(strlen(val) + n * strlen(device_name));
181 if (i <= 9 && off[i].rm_so >= 0) {
182 n = off[i].rm_eo - off[i].rm_so;
183 strncpy(p, device_name + off[i].rm_so, n);
192 alias = xstrdup(val + 1);
197 /* The rest (opt): command to run */
201 if (ENABLE_FEATURE_MDEV_EXEC) {
202 const char *s = "@$*";
203 const char *s2 = strchr(s, *val);
206 bb_error_msg_and_die("bad line %u", lineno);
208 /* Correlate the position in the "@$*" with the delete
209 * step so that we get the proper behavior:
210 * @cmd: run on create
211 * $cmd: run on delete
214 if ((s2 - s + 1) /*1/2/3*/ & /*1/2*/ (1 + delete)) {
215 command = xstrdup(val + 1);
218 /* end of field parsing */
219 break; /* we found matching line, stop */
222 } /* end of "while line is read from /etc/mdev.conf" */
224 free(line); /* in case we used "break" to get here */
229 if (!delete && sscanf(dev_maj_min, "%u:%u", &major, &minor) == 2) {
231 if (ENABLE_FEATURE_MDEV_RENAME)
234 if (mknod(device_name, mode | type, makedev(major, minor)) && errno != EEXIST)
235 bb_perror_msg_and_die("mknod %s", device_name);
237 if (major == root_major && minor == root_minor)
238 symlink(device_name, "root");
240 if (ENABLE_FEATURE_MDEV_CONF) {
241 chown(device_name, uid, gid);
243 if (ENABLE_FEATURE_MDEV_RENAME && alias) {
246 /* ">bar/": rename to bar/device_name */
247 /* ">bar[/]baz": rename to bar[/]baz */
248 dest = strrchr(alias, '/');
249 if (dest) { /* ">bar/[baz]" ? */
250 *dest = '\0'; /* mkdir bar */
251 bb_make_directory(alias, 0755, FILEUTILS_RECUR);
253 if (dest[1] == '\0') { /* ">bar/" => ">bar/device_name" */
255 alias = concat_path_file(alias, device_name);
260 /* recreate device_name as a symlink to moved device node */
261 if (rename(device_name, alias) == 0) {
262 symlink(alias, device_name);
270 if (ENABLE_FEATURE_MDEV_EXEC && command) {
271 /* setenv will leak memory, use putenv/unsetenv/free */
272 char *s = xasprintf("MDEV=%s", device_name);
274 if (system(command) == -1)
275 bb_perror_msg_and_die("can't run '%s'", command);
286 /* File callback for /sys/ traversal */
287 static int fileAction(const char *fileName,
288 struct stat *statbuf ATTRIBUTE_UNUSED,
290 int depth ATTRIBUTE_UNUSED)
292 size_t len = strlen(fileName) - 4; /* can't underflow */
293 char *scratch = userData;
295 /* len check is for paranoid reasons */
296 if (strcmp(fileName + len, "/dev") || len >= PATH_MAX)
299 strcpy(scratch, fileName);
301 make_device(scratch, 0);
306 /* Directory callback for /sys/ traversal */
307 static int dirAction(const char *fileName ATTRIBUTE_UNUSED,
308 struct stat *statbuf ATTRIBUTE_UNUSED,
309 void *userData ATTRIBUTE_UNUSED,
312 return (depth >= MAX_SYSFS_DEPTH ? SKIP : TRUE);
315 /* For the full gory details, see linux/Documentation/firmware_class/README
317 * Firmware loading works like this:
318 * - kernel sets FIRMWARE env var
319 * - userspace checks /lib/firmware/$FIRMWARE
320 * - userspace waits for /sys/$DEVPATH/loading to appear
321 * - userspace writes "1" to /sys/$DEVPATH/loading
322 * - userspace copies /lib/firmware/$FIRMWARE into /sys/$DEVPATH/data
323 * - userspace writes "0" (worked) or "-1" (failed) to /sys/$DEVPATH/loading
324 * - kernel loads firmware into device
326 static void load_firmware(const char *const firmware, const char *const sysfs_path)
329 int firmware_fd, loading_fd, data_fd;
331 /* check for /lib/firmware/$FIRMWARE */
332 xchdir("/lib/firmware");
333 firmware_fd = xopen(firmware, O_RDONLY);
335 /* in case we goto out ... */
338 /* check for /sys/$DEVPATH/loading ... give 30 seconds to appear */
340 for (cnt = 0; cnt < 30; ++cnt) {
341 loading_fd = open("loading", O_WRONLY);
342 if (loading_fd != -1)
349 /* tell kernel we're loading by `echo 1 > /sys/$DEVPATH/loading` */
350 if (full_write(loading_fd, "1", 1) != 1)
353 /* load firmware by `cat /lib/firmware/$FIRMWARE > /sys/$DEVPATH/data */
354 data_fd = open("data", O_WRONLY);
357 cnt = bb_copyfd_eof(firmware_fd, data_fd);
359 /* tell kernel result by `echo [0|-1] > /sys/$DEVPATH/loading` */
361 full_write(loading_fd, "0", 1);
363 full_write(loading_fd, "-1", 2);
366 if (ENABLE_FEATURE_CLEAN_UP) {
373 int mdev_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
374 int mdev_main(int argc, char **argv)
378 RESERVE_CONFIG_BUFFER(temp, PATH_MAX + SCRATCH_SIZE);
382 if (argc == 2 && !strcmp(argv[1], "-s")) {
389 root_major = major(st.st_dev);
390 root_minor = minor(st.st_dev);
392 recursive_action("/sys/block",
393 ACTION_RECURSE | ACTION_FOLLOWLINKS,
394 fileAction, dirAction, temp, 0);
396 recursive_action("/sys/class",
397 ACTION_RECURSE | ACTION_FOLLOWLINKS,
398 fileAction, dirAction, temp, 0);
402 * env ACTION=... DEVPATH=... mdev
403 * ACTION can be "add" or "remove"
404 * DEVPATH is like "/block/sda" or "/class/input/mice"
406 action = getenv("ACTION");
407 env_path = getenv("DEVPATH");
408 if (!action || !env_path)
411 snprintf(temp, PATH_MAX, "/sys%s", env_path);
412 if (!strcmp(action, "remove"))
413 make_device(temp, 1);
414 else if (!strcmp(action, "add")) {
415 make_device(temp, 0);
417 if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE) {
418 char *fw = getenv("FIRMWARE");
420 load_firmware(fw, temp);
425 if (ENABLE_FEATURE_CLEAN_UP)
426 RELEASE_CONFIG_BUFFER(temp);