1 /* vi: set sw=4 ts=4: */
3 * mdev - Mini udev for busybox
5 * Copyright 2005 Rob Landley <rob@landley.net>
6 * Copyright 2005 Frank Sorenson <frank@tuxrocks.com>
8 * Licensed under GPLv2, see file LICENSE in this source tree.
11 //config: bool "mdev (16 kb)"
13 //config: select PLATFORM_LINUX
15 //config: mdev is a mini-udev implementation for dynamically creating device
16 //config: nodes in the /dev directory.
18 //config: For more information, please see docs/mdev.txt
20 //config:config FEATURE_MDEV_CONF
21 //config: bool "Support /etc/mdev.conf"
23 //config: depends on MDEV
25 //config: Add support for the mdev config file to control ownership and
26 //config: permissions of the device nodes.
28 //config: For more information, please see docs/mdev.txt
30 //config:config FEATURE_MDEV_RENAME
31 //config: bool "Support subdirs/symlinks"
33 //config: depends on FEATURE_MDEV_CONF
35 //config: Add support for renaming devices and creating symlinks.
37 //config: For more information, please see docs/mdev.txt
39 //config:config FEATURE_MDEV_RENAME_REGEXP
40 //config: bool "Support regular expressions substitutions when renaming device"
42 //config: depends on FEATURE_MDEV_RENAME
44 //config: Add support for regular expressions substitutions when renaming
47 //config:config FEATURE_MDEV_EXEC
48 //config: bool "Support command execution at device addition/removal"
50 //config: depends on FEATURE_MDEV_CONF
52 //config: This adds support for an optional field to /etc/mdev.conf for
53 //config: executing commands when devices are created/removed.
55 //config: For more information, please see docs/mdev.txt
57 //config:config FEATURE_MDEV_LOAD_FIRMWARE
58 //config: bool "Support loading of firmware"
60 //config: depends on MDEV
62 //config: Some devices need to load firmware before they can be usable.
64 //config: These devices will request userspace look up the files in
65 //config: /lib/firmware/ and if it exists, send it to the kernel for
66 //config: loading into the hardware.
68 //applet:IF_MDEV(APPLET(mdev, BB_DIR_SBIN, BB_SUID_DROP))
70 //kbuild:lib-$(CONFIG_MDEV) += mdev.o
72 //usage:#define mdev_trivial_usage
74 //usage:#define mdev_full_usage "\n\n"
75 //usage: "mdev -s is to be run during boot to scan /sys and populate /dev.\n"
77 //usage: "Bare mdev is a kernel hotplug helper. To activate it:\n"
78 //usage: " echo /sbin/mdev >/proc/sys/kernel/hotplug\n"
79 //usage: IF_FEATURE_MDEV_CONF(
81 //usage: "It uses /etc/mdev.conf with lines\n"
82 //usage: " [-][ENV=regex;]...DEVNAME UID:GID PERM"
83 //usage: IF_FEATURE_MDEV_RENAME(" [>|=PATH]|[!]")
84 //usage: IF_FEATURE_MDEV_EXEC(" [@|$|*PROG]")
86 //usage: "where DEVNAME is device name regex, @major,minor[-minor2], or\n"
87 //usage: "environment variable regex. A common use of the latter is\n"
88 //usage: "to load modules for hotplugged devices:\n"
89 //usage: " $MODALIAS=.* 0:0 660 @modprobe \"$MODALIAS\"\n"
92 //usage: "If /dev/mdev.seq file exists, mdev will wait for its value\n"
93 //usage: "to match $SEQNUM variable. This prevents plug/unplug races.\n"
94 //usage: "To activate this feature, create empty /dev/mdev.seq at boot.\n"
96 //usage: "If /dev/mdev.log file exists, debug log will be appended to it."
99 #include "common_bufsiz.h"
102 /* "mdev -s" scans /sys/class/xxx, looking for directories which have dev
103 * file (it is of the form "M:m\n"). Example: /sys/class/tty/tty0/dev
104 * contains "4:0\n". Directory name is taken as device name, path component
105 * directly after /sys/class/ as subsystem. In this example, "tty0" and "tty".
106 * Then mdev creates the /dev/device_name node.
107 * If /sys/class/.../dev file does not exist, mdev still may act
108 * on this device: see "@|$|*command args..." parameter in config file.
110 * mdev w/o parameters is called as hotplug helper. It takes device
111 * and subsystem names from $DEVPATH and $SUBSYSTEM, extracts
112 * maj,min from "/sys/$DEVPATH/dev" and also examines
113 * $ACTION ("add"/"delete") and $FIRMWARE.
115 * If action is "add", mdev creates /dev/device_name similarly to mdev -s.
116 * (todo: explain "delete" and $FIRMWARE)
118 * If /etc/mdev.conf exists, it may modify /dev/device_name's properties.
120 * Leading minus in 1st field means "don't stop on this line", otherwise
121 * search is stopped after the matching line is encountered.
123 * $envvar=regex format is useful for loading modules for hot-plugged devices
124 * which do not have driver loaded yet. In this case /sys/class/.../dev
125 * does not exist, but $MODALIAS is set to needed module's name
126 * (actually, an alias to it) by kernel. This rule instructs mdev
127 * to load the module and exit:
128 * $MODALIAS=.* 0:0 660 @modprobe "$MODALIAS"
129 * The kernel will generate another hotplug event when /sys/class/.../dev
132 * When line matches, the device node is created, chmod'ed and chown'ed,
133 * moved to path, and if >path, a symlink to moved node is created,
134 * all this if /sys/class/.../dev exists.
136 * =loop/ - moves to /dev/loop
137 * >disk/sda%1 - moves to /dev/disk/sdaN, makes /dev/sdaN a symlink
139 * Then "command args..." is executed (via sh -c 'command args...').
140 * @:execute on creation, $:on deletion, *:on both.
141 * This happens regardless of /sys/class/.../dev existence.
144 /* Kernel's hotplug environment constantly changes.
145 * Here are new cases I observed on 3.1.0:
147 * Case with $DEVNAME and $DEVICE, not just $DEVPATH:
150 * DEVICE=/proc/bus/usb/001/003
151 * DEVNAME=bus/usb/001/003
153 * DEVPATH=/devices/pci0000:00/0000:00:02.1/usb1/1-5
157 * PRODUCT=18d1/4e12/227
161 * Case with $DEVICE, but no $DEVNAME - apparenty, usb iface notification?
162 * "Please load me a module" thing?
164 * DEVICE=/proc/bus/usb/001/003
165 * DEVPATH=/devices/pci0000:00/0000:00:02.1/usb1/1-5/1-5:1.0
166 * DEVTYPE=usb_interface
168 * MODALIAS=usb:v18D1p4E12d0227dc00dsc00dp00ic08isc06ip50
169 * PRODUCT=18d1/4e12/227
174 * DEVPATH=/devices/pci0000:00/0000:00:02.1/usb1/1-5/1-5:1.0/host5
179 * DEVPATH=/devices/pci0000:00/0000:00:02.1/usb1/1-5/1-5:1.0/host5/scsi_host/host5
180 * SUBSYSTEM=scsi_host
183 * DEVPATH=/devices/pci0000:00/0000:00:02.1/usb1/1-5/1-5:1.0/host5/target5:0:0
184 * DEVTYPE=scsi_target
187 * Case with strange $MODALIAS:
189 * DEVPATH=/devices/pci0000:00/0000:00:02.1/usb1/1-5/1-5:1.0/host5/target5:0:0/5:0:0:0
190 * DEVTYPE=scsi_device
191 * MODALIAS=scsi:t-0x00
195 * DEVPATH=/devices/pci0000:00/0000:00:02.1/usb1/1-5/1-5:1.0/host5/target5:0:0/5:0:0:0/scsi_disk/5:0:0:0
196 * SUBSYSTEM=scsi_disk
199 * DEVPATH=/devices/pci0000:00/0000:00:02.1/usb1/1-5/1-5:1.0/host5/target5:0:0/5:0:0:0/scsi_device/5:0:0:0
200 * SUBSYSTEM=scsi_device
202 * Case with explicit $MAJOR/$MINOR (no need to read /sys/$DEVPATH/dev?):
204 * DEVNAME=bsg/5:0:0:0
205 * DEVPATH=/devices/pci0000:00/0000:00:02.1/usb1/1-5/1-5:1.0/host5/target5:0:0/5:0:0:0/bsg/5:0:0:0
211 * DEVPATH=/devices/virtual/bdi/8:16
222 * Case with ACTION=change:
227 * DISK_MEDIA_CHANGE=1
236 # define dbg1(...) do { if (G.verbose) bb_error_msg(__VA_ARGS__); } while(0)
238 # define dbg1(...) ((void)0)
241 # define dbg2(...) do { if (G.verbose >= 2) bb_error_msg(__VA_ARGS__); } while(0)
243 # define dbg2(...) ((void)0)
246 # define dbg3(...) do { if (G.verbose >= 3) bb_error_msg(__VA_ARGS__); } while(0)
248 # define dbg3(...) ((void)0)
252 static const char keywords[] ALIGN1 = "add\0remove\0"; // "change\0"
253 enum { OP_add, OP_remove };
256 struct envmatch *next;
266 struct bb_uidgid_t ugid;
269 IF_FEATURE_MDEV_EXEC(char *r_cmd;)
271 struct envmatch *envmatch;
275 int root_major, root_minor;
278 char *subsys_env; /* for putenv("SUBSYSTEM=subsystem") */
279 #if ENABLE_FEATURE_MDEV_CONF
280 const char *filename;
282 struct rule **rule_vec;
285 struct rule cur_rule;
286 char timestr[sizeof("HH:MM:SS.123456")];
288 #define G (*(struct globals*)bb_common_bufsiz1)
289 #define INIT_G() do { \
290 setup_common_bufsiz(); \
291 IF_NOT_FEATURE_MDEV_CONF(G.cur_rule.maj = -1;) \
292 IF_NOT_FEATURE_MDEV_CONF(G.cur_rule.mode = 0660;) \
296 /* Prevent infinite loops in /sys symlinks */
297 #define MAX_SYSFS_DEPTH 3
299 /* We use additional bytes in make_device() */
300 #define SCRATCH_SIZE 128
302 #if ENABLE_FEATURE_MDEV_CONF
304 static void make_default_cur_rule(void)
306 memset(&G.cur_rule, 0, sizeof(G.cur_rule));
307 G.cur_rule.maj = -1; /* "not a @major,minor rule" */
308 G.cur_rule.mode = 0660;
311 static void clean_up_cur_rule(void)
315 free(G.cur_rule.envvar);
316 free(G.cur_rule.ren_mov);
317 if (G.cur_rule.regex_compiled)
318 regfree(&G.cur_rule.match);
319 IF_FEATURE_MDEV_EXEC(free(G.cur_rule.r_cmd);)
320 e = G.cur_rule.envmatch;
326 make_default_cur_rule();
329 static char *parse_envmatch_pfx(char *val)
331 struct envmatch **nextp = &G.cur_rule.envmatch;
336 char *eq = strchr(val, '=');
337 if (!eq /* || eq == val? */)
339 if (endofname(val) != eq)
341 semicolon = strchr(eq, ';');
344 /* ENVVAR=regex;... */
345 *nextp = e = xzalloc(sizeof(*e));
347 e->envname = xstrndup(val, eq - val);
349 xregcomp(&e->match, eq + 1, REG_EXTENDED);
355 static void parse_next_rule(void)
357 /* Note: on entry, G.cur_rule is set to default */
362 /* No PARSE_EOL_COMMENTS, because command may contain '#' chars */
363 if (!config_read(G.parser, tokens, 4, 3, "# \t", PARSE_NORMAL & ~PARSE_EOL_COMMENTS))
366 /* Fields: [-]regex uid:gid mode [alias] [cmd] */
367 dbg3("token1:'%s'", tokens[1]);
371 G.cur_rule.keep_matching = ('-' == val[0]);
372 val += G.cur_rule.keep_matching; /* swallow leading dash */
373 val = parse_envmatch_pfx(val);
375 /* @major,minor[-minor2] */
376 /* (useful when name is ambiguous:
377 * "/sys/class/usb/lp0" and
378 * "/sys/class/printer/lp0")
380 int sc = sscanf(val, "@%u,%u-%u", &G.cur_rule.maj, &G.cur_rule.min0, &G.cur_rule.min1);
381 if (sc < 2 || G.cur_rule.maj < 0) {
382 bb_error_msg("bad @maj,min on line %d", G.parser->lineno);
386 G.cur_rule.min1 = G.cur_rule.min0;
388 char *eq = strchr(val, '=');
390 /* $ENVVAR=regex ... */
393 bb_error_msg("bad $envvar=regex on line %d", G.parser->lineno);
396 G.cur_rule.envvar = xstrndup(val, eq - val);
399 xregcomp(&G.cur_rule.match, val, REG_EXTENDED);
400 G.cur_rule.regex_compiled = 1;
403 /* 2nd field: uid:gid - device ownership */
404 if (get_uidgid(&G.cur_rule.ugid, tokens[1]) == 0) {
405 bb_error_msg("unknown user/group '%s' on line %d", tokens[1], G.parser->lineno);
409 /* 3rd field: mode - device permissions */
410 G.cur_rule.mode = bb_parse_mode(tokens[2], G.cur_rule.mode);
412 /* 4th field (opt): ">|=alias" or "!" to not create the node */
414 if (ENABLE_FEATURE_MDEV_RENAME && val && strchr(">=!", val[0])) {
415 char *s = skip_non_whitespace(val);
416 G.cur_rule.ren_mov = xstrndup(val, s - val);
417 val = skip_whitespace(s);
420 if (ENABLE_FEATURE_MDEV_EXEC && val && val[0]) {
421 const char *s = "$@*";
422 const char *s2 = strchr(s, val[0]);
424 bb_error_msg("bad line %u", G.parser->lineno);
427 IF_FEATURE_MDEV_EXEC(G.cur_rule.r_cmd = xstrdup(val);)
433 } /* while (config_read) */
435 dbg3("config_close(G.parser)");
436 config_close(G.parser);
442 /* If mdev -s, we remember rules in G.rule_vec[].
443 * Otherwise, there is no point in doing it, and we just
444 * save only one parsed rule in G.cur_rule.
446 static const struct rule *next_rule(void)
450 /* Open conf file if we didn't do it yet */
451 if (!G.parser && G.filename) {
452 dbg3("config_open('%s')", G.filename);
453 G.parser = config_open2(G.filename, fopen_for_read);
459 /* Do we have rule parsed already? */
460 if (G.rule_vec[G.rule_idx]) {
461 dbg3("< G.rule_vec[G.rule_idx:%d]=%p", G.rule_idx, G.rule_vec[G.rule_idx]);
462 return G.rule_vec[G.rule_idx++];
464 make_default_cur_rule();
470 /* Parse one more rule if file isn't fully read */
474 if (G.rule_vec) { /* mdev -s */
475 rule = xmemdup(&G.cur_rule, sizeof(G.cur_rule));
476 G.rule_vec = xrealloc_vector(G.rule_vec, 4, G.rule_idx);
477 G.rule_vec[G.rule_idx++] = rule;
478 dbg3("> G.rule_vec[G.rule_idx:%d]=%p", G.rule_idx, G.rule_vec[G.rule_idx]);
485 static int env_matches(struct envmatch *e)
489 char *val = getenv(e->envname);
492 r = regexec(&e->match, val, /*size*/ 0, /*range[]*/ NULL, /*eflags*/ 0);
493 if (r != 0) /* no match */
502 # define next_rule() (&G.cur_rule)
506 static void mkdir_recursive(char *name)
508 /* if name has many levels ("dir1/dir2"),
509 * bb_make_directory() will create dir1 according to umask,
510 * not according to its "mode" parameter.
511 * Since we run with umask=0, need to temporarily switch it.
513 umask(022); /* "dir1" (if any) will be 0755 too */
514 bb_make_directory(name, 0755, FILEUTILS_RECUR);
518 /* Builds an alias path.
519 * This function potentionally reallocates the alias parameter.
520 * Only used for ENABLE_FEATURE_MDEV_RENAME
522 static char *build_alias(char *alias, const char *device_name)
526 /* ">bar/": rename to bar/device_name */
527 /* ">bar[/]baz": rename to bar[/]baz */
528 dest = strrchr(alias, '/');
529 if (dest) { /* ">bar/[baz]" ? */
530 *dest = '\0'; /* mkdir bar */
531 mkdir_recursive(alias);
533 if (dest[1] == '\0') { /* ">bar/" => ">bar/device_name" */
535 alias = concat_path_file(alias, device_name);
543 /* mknod in /dev based on a path like "/sys/block/hda/hda1"
544 * NB1: path parameter needs to have SCRATCH_SIZE scratch bytes
545 * after NUL, but we promise to not mangle it (IOW: to restore NUL if needed).
546 * NB2: "mdev -s" may call us many times, do not leak memory/fds!
548 * device_name = $DEVNAME (may be NULL)
549 * path = /sys/$DEVPATH
551 static void make_device(char *device_name, char *path, int operation)
553 int major, minor, type, len;
554 char *path_end = path + strlen(path);
556 /* Try to read major/minor string. Note that the kernel puts \n after
557 * the data, so we don't need to worry about null terminating the string
558 * because sscanf() will stop at the first nondigit, which \n is.
559 * We also depend on path having writeable space after it.
562 if (operation == OP_add) {
563 strcpy(path_end, "/dev");
564 len = open_read_close(path, path_end + 1, SCRATCH_SIZE - 1);
567 if (!ENABLE_FEATURE_MDEV_EXEC)
569 /* no "dev" file, but we can still run scripts
570 * based on device name */
571 } else if (sscanf(path_end + 1, "%u:%u", &major, &minor) == 2) {
572 dbg1("dev %u,%u", major, minor);
577 /* else: for delete, -1 still deletes the node, but < -1 suppresses that */
579 /* Determine device name */
582 * There was no $DEVNAME envvar (for example, mdev -s never has).
583 * But it is very useful: it contains the *path*, not only basename,
584 * Thankfully, uevent file has it.
585 * Example of .../sound/card0/controlC0/uevent file on Linux-3.7.7:
588 * DEVNAME=snd/controlC0
590 strcpy(path_end, "/uevent");
591 len = open_read_close(path, path_end + 1, SCRATCH_SIZE - 1);
595 path_end[1 + len] = '\0';
596 device_name = strstr(path_end + 1, "\nDEVNAME=");
598 device_name += sizeof("\nDEVNAME=")-1;
599 strchrnul(device_name, '\n')[0] = '\0';
601 /* Fall back to just basename */
602 device_name = (char*) bb_basename(path);
605 /* Determine device type */
607 * http://kernel.org/doc/pending/hotplug.txt says that only
608 * "/sys/block/..." is for block devices. "/sys/bus" etc is not.
609 * But since 2.6.25 block devices are also in /sys/class/block.
610 * We use strstr("/block/") to forestall future surprises.
613 if (strstr(path, "/block/") || (G.subsystem && is_prefixed_with(G.subsystem, "block")))
616 #if ENABLE_FEATURE_MDEV_CONF
617 G.rule_idx = 0; /* restart from the beginning (think mdev -s) */
620 const char *str_to_match;
621 regmatch_t off[1 + 9 * ENABLE_FEATURE_MDEV_RENAME_REGEXP];
624 char aliaslink = aliaslink; /* for compiler */
626 const struct rule *rule;
628 str_to_match = device_name;
632 #if ENABLE_FEATURE_MDEV_CONF
633 if (!env_matches(rule->envmatch))
635 if (rule->maj >= 0) { /* @maj,min rule */
636 if (major != rule->maj)
638 if (minor < rule->min0 || minor > rule->min1)
640 memset(off, 0, sizeof(off));
643 if (rule->envvar) { /* $envvar=regex rule */
644 str_to_match = getenv(rule->envvar);
645 dbg3("getenv('%s'):'%s'", rule->envvar, str_to_match);
649 /* else: str_to_match = device_name */
651 if (rule->regex_compiled) {
652 int regex_match = regexec(&rule->match, str_to_match, ARRAY_SIZE(off), off, 0);
653 dbg3("regex_match for '%s':%d", str_to_match, regex_match);
654 //bb_error_msg("matches:");
655 //for (int i = 0; i < ARRAY_SIZE(off); i++) {
656 // if (off[i].rm_so < 0) continue;
657 // bb_error_msg("match %d: '%.*s'\n", i,
658 // (int)(off[i].rm_eo - off[i].rm_so),
659 // device_name + off[i].rm_so);
663 /* regexec returns whole pattern as "range" 0 */
665 || (int)off[0].rm_eo != (int)strlen(str_to_match)
667 continue; /* this rule doesn't match */
670 /* else: it's final implicit "match-all" rule */
672 dbg2("rule matched, line %d", G.parser ? G.parser->lineno : -1);
674 /* Build alias name */
676 if (ENABLE_FEATURE_MDEV_RENAME && rule->ren_mov) {
677 aliaslink = rule->ren_mov[0];
678 if (aliaslink == '!') {
679 /* "!": suppress node creation/deletion */
682 else if (aliaslink == '>' || aliaslink == '=') {
683 if (ENABLE_FEATURE_MDEV_RENAME_REGEXP) {
688 /* substitute %1..9 with off[1..9], if any */
695 p = alias = xzalloc(strlen(rule->ren_mov) + n * strlen(str_to_match));
696 s = rule->ren_mov + 1;
700 unsigned i = (s[1] - '0');
701 if (i <= 9 && off[i].rm_so >= 0) {
702 n = off[i].rm_eo - off[i].rm_so;
703 strncpy(p, str_to_match + off[i].rm_so, n);
712 alias = xstrdup(rule->ren_mov + 1);
716 dbg3("alias:'%s'", alias);
719 IF_FEATURE_MDEV_EXEC(command = rule->r_cmd;)
721 /* Are we running this command now?
722 * Run @cmd on create, $cmd on delete, *cmd on any
724 if ((command[0] == '@' && operation == OP_add)
725 || (command[0] == '$' && operation == OP_remove)
726 || (command[0] == '*')
733 dbg3("command:'%s'", command);
735 /* "Execute" the line we found */
736 node_name = device_name;
737 if (ENABLE_FEATURE_MDEV_RENAME && alias) {
738 node_name = alias = build_alias(alias, device_name);
739 dbg3("alias2:'%s'", alias);
742 if (operation == OP_add && major >= 0) {
743 char *slash = strrchr(node_name, '/');
746 mkdir_recursive(node_name);
749 if (ENABLE_FEATURE_MDEV_CONF) {
750 dbg1("mknod %s (%d,%d) %o"
752 node_name, major, minor, rule->mode | type,
753 rule->ugid.uid, rule->ugid.gid
756 dbg1("mknod %s (%d,%d) %o",
757 node_name, major, minor, rule->mode | type
760 if (mknod(node_name, rule->mode | type, makedev(major, minor)) && errno != EEXIST)
761 bb_perror_msg("can't create '%s'", node_name);
762 if (ENABLE_FEATURE_MDEV_CONF) {
763 chmod(node_name, rule->mode);
764 chown(node_name, rule->ugid.uid, rule->ugid.gid);
766 if (major == G.root_major && minor == G.root_minor)
767 symlink(node_name, "root");
768 if (ENABLE_FEATURE_MDEV_RENAME && alias) {
769 if (aliaslink == '>') {
770 //TODO: on devtmpfs, device_name already exists and symlink() fails.
771 //End result is that instead of symlink, we have two nodes.
772 //What should be done?
773 dbg1("symlink: %s", device_name);
774 symlink(node_name, device_name);
779 if (ENABLE_FEATURE_MDEV_EXEC && command) {
780 /* setenv will leak memory, use putenv/unsetenv/free */
781 char *s = xasprintf("%s=%s", "MDEV", node_name);
783 dbg1("running: %s", command);
784 if (system(command) == -1)
785 bb_perror_msg("can't run '%s'", command);
786 bb_unsetenv_and_free(s);
789 if (operation == OP_remove && major >= -1) {
790 if (ENABLE_FEATURE_MDEV_RENAME && alias) {
791 if (aliaslink == '>') {
792 dbg1("unlink: %s", device_name);
796 dbg1("unlink: %s", node_name);
800 if (ENABLE_FEATURE_MDEV_RENAME)
803 /* We found matching line.
804 * Stop unless it was prefixed with '-'
806 if (!ENABLE_FEATURE_MDEV_CONF || !rule->keep_matching)
811 /* File callback for /sys/ traversal.
812 * We act only on "/sys/.../dev" (pseudo)file
814 static int FAST_FUNC fileAction(const char *fileName,
815 struct stat *statbuf UNUSED_PARAM,
817 int depth UNUSED_PARAM)
819 size_t len = strlen(fileName) - 4; /* can't underflow */
820 char *path = userData; /* char array[PATH_MAX + SCRATCH_SIZE] */
821 char subsys[PATH_MAX];
824 /* Is it a ".../dev" file? (len check is for paranoid reasons) */
825 if (strcmp(fileName + len, "/dev") != 0 || len >= PATH_MAX - 32)
826 return FALSE; /* not .../dev */
828 strcpy(path, fileName);
831 /* Read ".../subsystem" symlink in the same directory where ".../dev" is */
832 strcpy(subsys, path);
833 strcpy(subsys + len, "/subsystem");
834 res = readlink(subsys, subsys, sizeof(subsys)-1);
839 bb_unsetenv_and_free(G.subsys_env);
842 /* Set G.subsystem and $SUBSYSTEM from symlink's last component */
843 G.subsystem = strrchr(subsys, '/');
845 G.subsystem = xstrdup(G.subsystem + 1);
846 G.subsys_env = xasprintf("%s=%s", "SUBSYSTEM", G.subsystem);
847 putenv(G.subsys_env);
851 make_device(/*DEVNAME:*/ NULL, path, OP_add);
856 /* Directory callback for /sys/ traversal */
857 static int FAST_FUNC dirAction(const char *fileName UNUSED_PARAM,
858 struct stat *statbuf UNUSED_PARAM,
859 void *userData UNUSED_PARAM,
862 return (depth >= MAX_SYSFS_DEPTH ? SKIP : TRUE);
865 /* For the full gory details, see linux/Documentation/firmware_class/README
867 * Firmware loading works like this:
868 * - kernel sets FIRMWARE env var
869 * - userspace checks /lib/firmware/$FIRMWARE
870 * - userspace waits for /sys/$DEVPATH/loading to appear
871 * - userspace writes "1" to /sys/$DEVPATH/loading
872 * - userspace copies /lib/firmware/$FIRMWARE into /sys/$DEVPATH/data
873 * - userspace writes "0" (worked) or "-1" (failed) to /sys/$DEVPATH/loading
874 * - kernel loads firmware into device
876 static void load_firmware(const char *firmware, const char *sysfs_path)
879 int firmware_fd, loading_fd;
881 /* check for /lib/firmware/$FIRMWARE */
883 if (chdir("/lib/firmware") == 0)
884 firmware_fd = open(firmware, O_RDONLY); /* can fail */
886 /* check for /sys/$DEVPATH/loading ... give 30 seconds to appear */
888 for (cnt = 0; cnt < 30; ++cnt) {
889 loading_fd = open("loading", O_WRONLY);
898 if (firmware_fd >= 0) {
901 /* tell kernel we're loading by "echo 1 > /sys/$DEVPATH/loading" */
902 if (full_write(loading_fd, "1", 1) != 1)
905 /* load firmware into /sys/$DEVPATH/data */
906 data_fd = open("data", O_WRONLY);
909 cnt = bb_copyfd_eof(firmware_fd, data_fd);
910 if (ENABLE_FEATURE_CLEAN_UP)
914 /* Tell kernel result by "echo [0|-1] > /sys/$DEVPATH/loading"
915 * Note: we emit -1 also if firmware file wasn't found.
916 * There are cases when otherwise kernel would wait for minutes
920 full_write(loading_fd, "0", 1);
922 full_write(loading_fd, "-1", 2);
926 if (ENABLE_FEATURE_CLEAN_UP) {
932 static char *curtime(void)
935 gettimeofday(&tv, NULL);
937 strftime_HHMMSS(G.timestr, sizeof(G.timestr), &tv.tv_sec),
944 static void open_mdev_log(const char *seq, unsigned my_pid)
946 int logfd = open("mdev.log", O_WRONLY | O_APPEND);
948 xmove_fd(logfd, STDERR_FILENO);
950 applet_name = xasprintf("%s[%s]", applet_name, seq ? seq : utoa(my_pid));
954 /* If it exists, does /dev/mdev.seq match $SEQNUM?
955 * If it does not match, earlier mdev is running
956 * in parallel, and we need to wait.
957 * Active mdev pokes us with SIGCHLD to check the new file.
960 wait_for_seqfile(unsigned expected_seq)
962 /* We time out after 2 sec */
963 static const struct timespec ts = { 0, 32*1000*1000 };
964 int timeout = 2000 / 32;
969 sigemptyset(&set_CHLD);
970 sigaddset(&set_CHLD, SIGCHLD);
971 sigprocmask(SIG_BLOCK, &set_CHLD, NULL);
975 char seqbuf[sizeof(long)*3 + 2];
979 seq_fd = open("mdev.seq", O_RDWR);
982 close_on_exec_on(seq_fd);
984 seqlen = pread(seq_fd, seqbuf, sizeof(seqbuf) - 1, 0);
990 seqbuf[seqlen] = '\0';
991 if (seqbuf[0] == '\n' || seqbuf[0] == '\0') {
992 /* seed file: write out seq ASAP */
993 xwrite_str(seq_fd, utoa(expected_seq));
994 xlseek(seq_fd, 0, SEEK_SET);
995 dbg2("first seq written");
998 seqbufnum = atoll(seqbuf);
999 if (seqbufnum == expected_seq) {
1003 if (seqbufnum > expected_seq) {
1004 /* a later mdev runs already (this was seen by users to happen) */
1005 /* do not overwrite seqfile on exit */
1011 dbg2("%s mdev.seq='%s', need '%u'", curtime(), seqbuf, expected_seq);
1014 if (sigtimedwait(&set_CHLD, NULL, &ts) >= 0) {
1016 continue; /* don't decrement timeout! */
1018 if (--timeout == 0) {
1019 dbg1("%s mdev.seq='%s'", "timed out", seqbuf);
1023 sigprocmask(SIG_UNBLOCK, &set_CHLD, NULL);
1027 static void signal_mdevs(unsigned my_pid)
1029 procps_status_t* p = NULL;
1030 while ((p = procps_scan(p, PSSCAN_ARGV0)) != NULL) {
1031 if (p->pid != my_pid
1033 && strcmp(bb_basename(p->argv0), "mdev") == 0
1035 kill(p->pid, SIGCHLD);
1040 int mdev_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
1041 int mdev_main(int argc UNUSED_PARAM, char **argv)
1043 RESERVE_CONFIG_BUFFER(temp, PATH_MAX + SCRATCH_SIZE);
1047 #if ENABLE_FEATURE_MDEV_CONF
1048 G.filename = "/etc/mdev.conf";
1051 /* We can be called as hotplug helper */
1052 /* Kernel cannot provide suitable stdio fds for us, do it ourself */
1053 bb_sanitize_stdio();
1055 /* Force the configuration file settings exactly */
1060 if (argv[1] && strcmp(argv[1], "-s") == 0) {
1066 #if ENABLE_FEATURE_MDEV_CONF
1067 /* Same as xrealloc_vector(NULL, 4, 0): */
1068 G.rule_vec = xzalloc((1 << 4) * sizeof(*G.rule_vec));
1071 G.root_major = major(st.st_dev);
1072 G.root_minor = minor(st.st_dev);
1074 putenv((char*)"ACTION=add");
1076 /* Create all devices from /sys/dev hierarchy */
1077 recursive_action("/sys/dev",
1078 ACTION_RECURSE | ACTION_FOLLOWLINKS,
1079 fileAction, dirAction, temp, 0);
1087 unsigned seqnum = seqnum; /* for compiler */
1092 * env ACTION=... DEVPATH=... SUBSYSTEM=... [SEQNUM=...] mdev
1093 * ACTION can be "add", "remove", "change"
1094 * DEVPATH is like "/block/sda" or "/class/input/mice"
1096 env_devname = getenv("DEVNAME"); /* can be NULL */
1097 G.subsystem = getenv("SUBSYSTEM");
1098 action = getenv("ACTION");
1099 env_devpath = getenv("DEVPATH");
1100 if (!action || !env_devpath /*|| !G.subsystem*/)
1102 fw = getenv("FIRMWARE");
1103 seq = getenv("SEQNUM");
1104 op = index_in_strings(keywords, action);
1107 open_mdev_log(seq, my_pid);
1111 seqnum = atoll(seq);
1112 seq_fd = wait_for_seqfile(seqnum);
1116 "ACTION:%s SUBSYSTEM:%s DEVNAME:%s DEVPATH:%s"
1119 action, G.subsystem, env_devname, env_devpath,
1120 fw ? " FW:" : "", fw ? fw : ""
1123 snprintf(temp, PATH_MAX, "/sys%s", env_devpath);
1124 if (op == OP_remove) {
1125 /* Ignoring "remove firmware". It was reported
1126 * to happen and to cause erroneous deletion
1127 * of device nodes. */
1129 make_device(env_devname, temp, op);
1132 make_device(env_devname, temp, op);
1133 if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE) {
1134 if (op == OP_add && fw)
1135 load_firmware(fw, temp);
1139 dbg1("%s exiting", curtime());
1141 xwrite_str(seq_fd, utoa(seqnum + 1));
1142 signal_mdevs(my_pid);
1146 if (ENABLE_FEATURE_CLEAN_UP)
1147 RELEASE_CONFIG_BUFFER(temp);
1149 return EXIT_SUCCESS;