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1/* vi: set sw=4 ts=4: */
2/*
3 * mdev - Mini udev for busybox
4 *
5 * Copyright 2005 Rob Landley <rob@landley.net>
6 * Copyright 2005 Frank Sorenson <frank@tuxrocks.com>
7 *
8 * Licensed under GPLv2, see file LICENSE in this source tree.
9 */
10
11//config:config MDEV
12//config: bool "mdev"
13//config: default y
14//config: select PLATFORM_LINUX
15//config: help
16//config: mdev is a mini-udev implementation for dynamically creating device
17//config: nodes in the /dev directory.
18//config:
19//config: For more information, please see docs/mdev.txt
20//config:
21//config:config FEATURE_MDEV_CONF
22//config: bool "Support /etc/mdev.conf"
23//config: default y
24//config: depends on MDEV
25//config: help
26//config: Add support for the mdev config file to control ownership and
27//config: permissions of the device nodes.
28//config:
29//config: For more information, please see docs/mdev.txt
30//config:
31//config:config FEATURE_MDEV_RENAME
32//config: bool "Support subdirs/symlinks"
33//config: default y
34//config: depends on FEATURE_MDEV_CONF
35//config: help
36//config: Add support for renaming devices and creating symlinks.
37//config:
38//config: For more information, please see docs/mdev.txt
39//config:
40//config:config FEATURE_MDEV_RENAME_REGEXP
41//config: bool "Support regular expressions substitutions when renaming device"
42//config: default y
43//config: depends on FEATURE_MDEV_RENAME
44//config: help
45//config: Add support for regular expressions substitutions when renaming
46//config: device.
47//config:
48//config:config FEATURE_MDEV_EXEC
49//config: bool "Support command execution at device addition/removal"
50//config: default y
51//config: depends on FEATURE_MDEV_CONF
52//config: help
53//config: This adds support for an optional field to /etc/mdev.conf for
54//config: executing commands when devices are created/removed.
55//config:
56//config: For more information, please see docs/mdev.txt
57//config:
58//config:config FEATURE_MDEV_LOAD_FIRMWARE
59//config: bool "Support loading of firmwares"
60//config: default y
61//config: depends on MDEV
62//config: help
63//config: Some devices need to load firmware before they can be usable.
64//config:
65//config: These devices will request userspace look up the files in
66//config: /lib/firmware/ and if it exists, send it to the kernel for
67//config: loading into the hardware.
68
69//applet:IF_MDEV(APPLET(mdev, BB_DIR_SBIN, BB_SUID_DROP))
70
71//kbuild:lib-$(CONFIG_MDEV) += mdev.o
72
73//usage:#define mdev_trivial_usage
74//usage: "[-s]"
75//usage:#define mdev_full_usage "\n\n"
76//usage: "mdev -s is to be run during boot to scan /sys and populate /dev.\n"
77//usage: "\n"
78//usage: "Bare mdev is a kernel hotplug helper. To activate it:\n"
79//usage: " echo /sbin/mdev >/proc/sys/kernel/hotplug\n"
80//usage: IF_FEATURE_MDEV_CONF(
81//usage: "\n"
82//usage: "It uses /etc/mdev.conf with lines\n"
83//usage: " [-][ENV=regex;]...DEVNAME UID:GID PERM"
84//usage: IF_FEATURE_MDEV_RENAME(" [>|=PATH]|[!]")
85//usage: IF_FEATURE_MDEV_EXEC(" [@|$|*PROG]")
86//usage: "\n"
87//usage: "where DEVNAME is device name regex, @major,minor[-minor2], or\n"
88//usage: "environment variable regex. A common use of the latter is\n"
89//usage: "to load modules for hotplugged devices:\n"
90//usage: " $MODALIAS=.* 0:0 660 @modprobe \"$MODALIAS\"\n"
91//usage: )
92//usage: "\n"
93//usage: "If /dev/mdev.seq file exists, mdev will wait for its value\n"
94//usage: "to match $SEQNUM variable. This prevents plug/unplug races.\n"
95//usage: "To activate this feature, create empty /dev/mdev.seq at boot.\n"
96//usage: "\n"
97//usage: "If /dev/mdev.log file exists, debug log will be appended to it."
98
99#include "libbb.h"
100#include "xregex.h"
101
102/* "mdev -s" scans /sys/class/xxx, looking for directories which have dev
103 * file (it is of the form "M:m\n"). Example: /sys/class/tty/tty0/dev
104 * contains "4:0\n". Directory name is taken as device name, path component
105 * directly after /sys/class/ as subsystem. In this example, "tty0" and "tty".
106 * Then mdev creates the /dev/device_name node.
107 * If /sys/class/.../dev file does not exist, mdev still may act
108 * on this device: see "@|$|*command args..." parameter in config file.
109 *
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.
114 *
115 * If action is "add", mdev creates /dev/device_name similarly to mdev -s.
116 * (todo: explain "delete" and $FIRMWARE)
117 *
118 * If /etc/mdev.conf exists, it may modify /dev/device_name's properties.
119 *
120 * Leading minus in 1st field means "don't stop on this line", otherwise
121 * search is stopped after the matching line is encountered.
122 *
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
130 * file appears.
131 *
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.
135 * Examples:
136 * =loop/ - moves to /dev/loop
137 * >disk/sda%1 - moves to /dev/disk/sdaN, makes /dev/sdaN a symlink
138 *
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.
142 */
143
144/* Kernel's hotplug environment constantly changes.
145 * Here are new cases I observed on 3.1.0:
146 *
147 * Case with $DEVNAME and $DEVICE, not just $DEVPATH:
148 * ACTION=add
149 * BUSNUM=001
150 * DEVICE=/proc/bus/usb/001/003
151 * DEVNAME=bus/usb/001/003
152 * DEVNUM=003
153 * DEVPATH=/devices/pci0000:00/0000:00:02.1/usb1/1-5
154 * DEVTYPE=usb_device
155 * MAJOR=189
156 * MINOR=2
157 * PRODUCT=18d1/4e12/227
158 * SUBSYSTEM=usb
159 * TYPE=0/0/0
160 *
161 * Case with $DEVICE, but no $DEVNAME - apparenty, usb iface notification?
162 * "Please load me a module" thing?
163 * ACTION=add
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
167 * INTERFACE=8/6/80
168 * MODALIAS=usb:v18D1p4E12d0227dc00dsc00dp00ic08isc06ip50
169 * PRODUCT=18d1/4e12/227
170 * SUBSYSTEM=usb
171 * TYPE=0/0/0
172 *
173 * ACTION=add
174 * DEVPATH=/devices/pci0000:00/0000:00:02.1/usb1/1-5/1-5:1.0/host5
175 * DEVTYPE=scsi_host
176 * SUBSYSTEM=scsi
177 *
178 * ACTION=add
179 * DEVPATH=/devices/pci0000:00/0000:00:02.1/usb1/1-5/1-5:1.0/host5/scsi_host/host5
180 * SUBSYSTEM=scsi_host
181 *
182 * ACTION=add
183 * DEVPATH=/devices/pci0000:00/0000:00:02.1/usb1/1-5/1-5:1.0/host5/target5:0:0
184 * DEVTYPE=scsi_target
185 * SUBSYSTEM=scsi
186 *
187 * Case with strange $MODALIAS:
188 * ACTION=add
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
192 * SUBSYSTEM=scsi
193 *
194 * ACTION=add
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
197 *
198 * ACTION=add
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
201 *
202 * Case with explicit $MAJOR/$MINOR (no need to read /sys/$DEVPATH/dev?):
203 * ACTION=add
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
206 * MAJOR=253
207 * MINOR=1
208 * SUBSYSTEM=bsg
209 *
210 * ACTION=add
211 * DEVPATH=/devices/virtual/bdi/8:16
212 * SUBSYSTEM=bdi
213 *
214 * ACTION=add
215 * DEVNAME=sdb
216 * DEVPATH=/block/sdb
217 * DEVTYPE=disk
218 * MAJOR=8
219 * MINOR=16
220 * SUBSYSTEM=block
221 *
222 * Case with ACTION=change:
223 * ACTION=change
224 * DEVNAME=sdb
225 * DEVPATH=/block/sdb
226 * DEVTYPE=disk
227 * DISK_MEDIA_CHANGE=1
228 * MAJOR=8
229 * MINOR=16
230 * SUBSYSTEM=block
231 */
232
233#define DEBUG_LVL 2
234
235#if DEBUG_LVL >= 1
236# define dbg1(...) do { if (G.verbose) bb_error_msg(__VA_ARGS__); } while(0)
237#else
238# define dbg1(...) ((void)0)
239#endif
240#if DEBUG_LVL >= 2
241# define dbg2(...) do { if (G.verbose >= 2) bb_error_msg(__VA_ARGS__); } while(0)
242#else
243# define dbg2(...) ((void)0)
244#endif
245#if DEBUG_LVL >= 3
246# define dbg3(...) do { if (G.verbose >= 3) bb_error_msg(__VA_ARGS__); } while(0)
247#else
248# define dbg3(...) ((void)0)
249#endif
250
251
252static const char keywords[] ALIGN1 = "add\0remove\0"; // "change\0"
253enum { OP_add, OP_remove };
254
255struct envmatch {
256 struct envmatch *next;
257 char *envname;
258 regex_t match;
259};
260
261struct rule {
262 bool keep_matching;
263 bool regex_compiled;
264 mode_t mode;
265 int maj, min0, min1;
266 struct bb_uidgid_t ugid;
267 char *envvar;
268 char *ren_mov;
269 IF_FEATURE_MDEV_EXEC(char *r_cmd;)
270 regex_t match;
271 struct envmatch *envmatch;
272};
273
274struct globals {
275 int root_major, root_minor;
276 smallint verbose;
277 char *subsystem;
278 char *subsys_env; /* for putenv("SUBSYSTEM=subsystem") */
279#if ENABLE_FEATURE_MDEV_CONF
280 const char *filename;
281 parser_t *parser;
282 struct rule **rule_vec;
283 unsigned rule_idx;
284#endif
285 struct rule cur_rule;
286 char timestr[sizeof("60.123456")];
287} FIX_ALIASING;
288#define G (*(struct globals*)&bb_common_bufsiz1)
289#define INIT_G() do { \
290 IF_NOT_FEATURE_MDEV_CONF(G.cur_rule.maj = -1;) \
291 IF_NOT_FEATURE_MDEV_CONF(G.cur_rule.mode = 0660;) \
292} while (0)
293
294
295/* Prevent infinite loops in /sys symlinks */
296#define MAX_SYSFS_DEPTH 3
297
298/* We use additional bytes in make_device() */
299#define SCRATCH_SIZE 128
300
301#if ENABLE_FEATURE_MDEV_CONF
302
303static void make_default_cur_rule(void)
304{
305 memset(&G.cur_rule, 0, sizeof(G.cur_rule));
306 G.cur_rule.maj = -1; /* "not a @major,minor rule" */
307 G.cur_rule.mode = 0660;
308}
309
310static void clean_up_cur_rule(void)
311{
312 struct envmatch *e;
313
314 free(G.cur_rule.envvar);
315 free(G.cur_rule.ren_mov);
316 if (G.cur_rule.regex_compiled)
317 regfree(&G.cur_rule.match);
318 IF_FEATURE_MDEV_EXEC(free(G.cur_rule.r_cmd);)
319 e = G.cur_rule.envmatch;
320 while (e) {
321 free(e->envname);
322 regfree(&e->match);
323 e = e->next;
324 }
325 make_default_cur_rule();
326}
327
328static char *parse_envmatch_pfx(char *val)
329{
330 struct envmatch **nextp = &G.cur_rule.envmatch;
331
332 for (;;) {
333 struct envmatch *e;
334 char *semicolon;
335 char *eq = strchr(val, '=');
336 if (!eq /* || eq == val? */)
337 return val;
338 if (endofname(val) != eq)
339 return val;
340 semicolon = strchr(eq, ';');
341 if (!semicolon)
342 return val;
343 /* ENVVAR=regex;... */
344 *nextp = e = xzalloc(sizeof(*e));
345 nextp = &e->next;
346 e->envname = xstrndup(val, eq - val);
347 *semicolon = '\0';
348 xregcomp(&e->match, eq + 1, REG_EXTENDED);
349 *semicolon = ';';
350 val = semicolon + 1;
351 }
352}
353
354static void parse_next_rule(void)
355{
356 /* Note: on entry, G.cur_rule is set to default */
357 while (1) {
358 char *tokens[4];
359 char *val;
360
361 /* No PARSE_EOL_COMMENTS, because command may contain '#' chars */
362 if (!config_read(G.parser, tokens, 4, 3, "# \t", PARSE_NORMAL & ~PARSE_EOL_COMMENTS))
363 break;
364
365 /* Fields: [-]regex uid:gid mode [alias] [cmd] */
366 dbg3("token1:'%s'", tokens[1]);
367
368 /* 1st field */
369 val = tokens[0];
370 G.cur_rule.keep_matching = ('-' == val[0]);
371 val += G.cur_rule.keep_matching; /* swallow leading dash */
372 val = parse_envmatch_pfx(val);
373 if (val[0] == '@') {
374 /* @major,minor[-minor2] */
375 /* (useful when name is ambiguous:
376 * "/sys/class/usb/lp0" and
377 * "/sys/class/printer/lp0")
378 */
379 int sc = sscanf(val, "@%u,%u-%u", &G.cur_rule.maj, &G.cur_rule.min0, &G.cur_rule.min1);
380 if (sc < 2 || G.cur_rule.maj < 0) {
381 bb_error_msg("bad @maj,min on line %d", G.parser->lineno);
382 goto next_rule;
383 }
384 if (sc == 2)
385 G.cur_rule.min1 = G.cur_rule.min0;
386 } else {
387 char *eq = strchr(val, '=');
388 if (val[0] == '$') {
389 /* $ENVVAR=regex ... */
390 val++;
391 if (!eq) {
392 bb_error_msg("bad $envvar=regex on line %d", G.parser->lineno);
393 goto next_rule;
394 }
395 G.cur_rule.envvar = xstrndup(val, eq - val);
396 val = eq + 1;
397 }
398 xregcomp(&G.cur_rule.match, val, REG_EXTENDED);
399 G.cur_rule.regex_compiled = 1;
400 }
401
402 /* 2nd field: uid:gid - device ownership */
403 if (get_uidgid(&G.cur_rule.ugid, tokens[1], /*allow_numeric:*/ 1) == 0) {
404 bb_error_msg("unknown user/group '%s' on line %d", tokens[1], G.parser->lineno);
405 goto next_rule;
406 }
407
408 /* 3rd field: mode - device permissions */
409 bb_parse_mode(tokens[2], &G.cur_rule.mode);
410
411 /* 4th field (opt): ">|=alias" or "!" to not create the node */
412 val = tokens[3];
413 if (ENABLE_FEATURE_MDEV_RENAME && val && strchr(">=!", val[0])) {
414 char *s = skip_non_whitespace(val);
415 G.cur_rule.ren_mov = xstrndup(val, s - val);
416 val = skip_whitespace(s);
417 }
418
419 if (ENABLE_FEATURE_MDEV_EXEC && val && val[0]) {
420 const char *s = "$@*";
421 const char *s2 = strchr(s, val[0]);
422 if (!s2) {
423 bb_error_msg("bad line %u", G.parser->lineno);
424 goto next_rule;
425 }
426 IF_FEATURE_MDEV_EXEC(G.cur_rule.r_cmd = xstrdup(val);)
427 }
428
429 return;
430 next_rule:
431 clean_up_cur_rule();
432 } /* while (config_read) */
433
434 dbg3("config_close(G.parser)");
435 config_close(G.parser);
436 G.parser = NULL;
437
438 return;
439}
440
441/* If mdev -s, we remember rules in G.rule_vec[].
442 * Otherwise, there is no point in doing it, and we just
443 * save only one parsed rule in G.cur_rule.
444 */
445static const struct rule *next_rule(void)
446{
447 struct rule *rule;
448
449 /* Open conf file if we didn't do it yet */
450 if (!G.parser && G.filename) {
451 dbg3("config_open('%s')", G.filename);
452 G.parser = config_open2(G.filename, fopen_for_read);
453 G.filename = NULL;
454 }
455
456 if (G.rule_vec) {
457 /* mdev -s */
458 /* Do we have rule parsed already? */
459 if (G.rule_vec[G.rule_idx]) {
460 dbg3("< G.rule_vec[G.rule_idx:%d]=%p", G.rule_idx, G.rule_vec[G.rule_idx]);
461 return G.rule_vec[G.rule_idx++];
462 }
463 make_default_cur_rule();
464 } else {
465 /* not mdev -s */
466 clean_up_cur_rule();
467 }
468
469 /* Parse one more rule if file isn't fully read */
470 rule = &G.cur_rule;
471 if (G.parser) {
472 parse_next_rule();
473 if (G.rule_vec) { /* mdev -s */
474 rule = memcpy(xmalloc(sizeof(G.cur_rule)), &G.cur_rule, sizeof(G.cur_rule));
475 G.rule_vec = xrealloc_vector(G.rule_vec, 4, G.rule_idx);
476 G.rule_vec[G.rule_idx++] = rule;
477 dbg3("> G.rule_vec[G.rule_idx:%d]=%p", G.rule_idx, G.rule_vec[G.rule_idx]);
478 }
479 }
480
481 return rule;
482}
483
484static int env_matches(struct envmatch *e)
485{
486 while (e) {
487 int r;
488 char *val = getenv(e->envname);
489 if (!val)
490 return 0;
491 r = regexec(&e->match, val, /*size*/ 0, /*range[]*/ NULL, /*eflags*/ 0);
492 if (r != 0) /* no match */
493 return 0;
494 e = e->next;
495 }
496 return 1;
497}
498
499#else
500
501# define next_rule() (&G.cur_rule)
502
503#endif
504
505static void mkdir_recursive(char *name)
506{
507 /* if name has many levels ("dir1/dir2"),
508 * bb_make_directory() will create dir1 according to umask,
509 * not according to its "mode" parameter.
510 * Since we run with umask=0, need to temporarily switch it.
511 */
512 umask(022); /* "dir1" (if any) will be 0755 too */
513 bb_make_directory(name, 0755, FILEUTILS_RECUR);
514 umask(0);
515}
516
517/* Builds an alias path.
518 * This function potentionally reallocates the alias parameter.
519 * Only used for ENABLE_FEATURE_MDEV_RENAME
520 */
521static char *build_alias(char *alias, const char *device_name)
522{
523 char *dest;
524
525 /* ">bar/": rename to bar/device_name */
526 /* ">bar[/]baz": rename to bar[/]baz */
527 dest = strrchr(alias, '/');
528 if (dest) { /* ">bar/[baz]" ? */
529 *dest = '\0'; /* mkdir bar */
530 mkdir_recursive(alias);
531 *dest = '/';
532 if (dest[1] == '\0') { /* ">bar/" => ">bar/device_name" */
533 dest = alias;
534 alias = concat_path_file(alias, device_name);
535 free(dest);
536 }
537 }
538
539 return alias;
540}
541
542/* mknod in /dev based on a path like "/sys/block/hda/hda1"
543 * NB1: path parameter needs to have SCRATCH_SIZE scratch bytes
544 * after NUL, but we promise to not mangle (IOW: to restore NUL if needed)
545 * path string.
546 * NB2: "mdev -s" may call us many times, do not leak memory/fds!
547 *
548 * device_name = $DEVNAME (may be NULL)
549 * path = /sys/$DEVPATH
550 */
551static void make_device(char *device_name, char *path, int operation)
552{
553 int major, minor, type, len;
554 char *path_end = path + strlen(path);
555
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.
560 */
561 major = -1;
562 if (operation == OP_add) {
563 strcpy(path_end, "/dev");
564 len = open_read_close(path, path_end + 1, SCRATCH_SIZE - 1);
565 *path_end = '\0';
566 if (len < 1) {
567 if (!ENABLE_FEATURE_MDEV_EXEC)
568 return;
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);
573 } else {
574 major = -1;
575 }
576 }
577 /* else: for delete, -1 still deletes the node, but < -1 suppresses that */
578
579 /* Determine device name */
580 if (!device_name) {
581 /*
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:
586 * MAJOR=116
587 * MINOR=7
588 * DEVNAME=snd/controlC0
589 */
590 strcpy(path_end, "/uevent");
591 len = open_read_close(path, path_end + 1, SCRATCH_SIZE - 1);
592 if (len < 0)
593 len = 0;
594 *path_end = '\0';
595 path_end[1 + len] = '\0';
596 device_name = strstr(path_end + 1, "\nDEVNAME=");
597 if (device_name) {
598 device_name += sizeof("\nDEVNAME=")-1;
599 strchrnul(device_name, '\n')[0] = '\0';
600 } else {
601 /* Fall back to just basename */
602 device_name = (char*) bb_basename(path);
603 }
604 }
605 /* Determine device type */
606 /*
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.
611 */
612 type = S_IFCHR;
613 if (strstr(path, "/block/") || (G.subsystem && strncmp(G.subsystem, "block", 5) == 0))
614 type = S_IFBLK;
615
616#if ENABLE_FEATURE_MDEV_CONF
617 G.rule_idx = 0; /* restart from the beginning (think mdev -s) */
618#endif
619 for (;;) {
620 const char *str_to_match;
621 regmatch_t off[1 + 9 * ENABLE_FEATURE_MDEV_RENAME_REGEXP];
622 char *command;
623 char *alias;
624 char aliaslink = aliaslink; /* for compiler */
625 char *node_name;
626 const struct rule *rule;
627
628 str_to_match = device_name;
629
630 rule = next_rule();
631
632#if ENABLE_FEATURE_MDEV_CONF
633 if (!env_matches(rule->envmatch))
634 continue;
635 if (rule->maj >= 0) { /* @maj,min rule */
636 if (major != rule->maj)
637 continue;
638 if (minor < rule->min0 || minor > rule->min1)
639 continue;
640 memset(off, 0, sizeof(off));
641 goto rule_matches;
642 }
643 if (rule->envvar) { /* $envvar=regex rule */
644 str_to_match = getenv(rule->envvar);
645 dbg3("getenv('%s'):'%s'", rule->envvar, str_to_match);
646 if (!str_to_match)
647 continue;
648 }
649 /* else: str_to_match = device_name */
650
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);
660 //}
661
662 if (regex_match != 0
663 /* regexec returns whole pattern as "range" 0 */
664 || off[0].rm_so != 0
665 || (int)off[0].rm_eo != (int)strlen(str_to_match)
666 ) {
667 continue; /* this rule doesn't match */
668 }
669 }
670 /* else: it's final implicit "match-all" rule */
671 rule_matches:
672 dbg2("rule matched, line %d", G.parser ? G.parser->lineno : -1);
673#endif
674 /* Build alias name */
675 alias = NULL;
676 if (ENABLE_FEATURE_MDEV_RENAME && rule->ren_mov) {
677 aliaslink = rule->ren_mov[0];
678 if (aliaslink == '!') {
679 /* "!": suppress node creation/deletion */
680 major = -2;
681 }
682 else if (aliaslink == '>' || aliaslink == '=') {
683 if (ENABLE_FEATURE_MDEV_RENAME_REGEXP) {
684 char *s;
685 char *p;
686 unsigned n;
687
688 /* substitute %1..9 with off[1..9], if any */
689 n = 0;
690 s = rule->ren_mov;
691 while (*s)
692 if (*s++ == '%')
693 n++;
694
695 p = alias = xzalloc(strlen(rule->ren_mov) + n * strlen(str_to_match));
696 s = rule->ren_mov + 1;
697 while (*s) {
698 *p = *s;
699 if ('%' == *s) {
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);
704 p += n - 1;
705 s++;
706 }
707 }
708 p++;
709 s++;
710 }
711 } else {
712 alias = xstrdup(rule->ren_mov + 1);
713 }
714 }
715 }
716 dbg3("alias:'%s'", alias);
717
718 command = NULL;
719 IF_FEATURE_MDEV_EXEC(command = rule->r_cmd;)
720 if (command) {
721 /* Are we running this command now?
722 * Run @cmd on create, $cmd on delete, *cmd on any
723 */
724 if ((command[0] == '@' && operation == OP_add)
725 || (command[0] == '$' && operation == OP_remove)
726 || (command[0] == '*')
727 ) {
728 command++;
729 } else {
730 command = NULL;
731 }
732 }
733 dbg3("command:'%s'", command);
734
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);
740 }
741
742 if (operation == OP_add && major >= 0) {
743 char *slash = strrchr(node_name, '/');
744 if (slash) {
745 *slash = '\0';
746 mkdir_recursive(node_name);
747 *slash = '/';
748 }
749 if (ENABLE_FEATURE_MDEV_CONF) {
750 dbg1("mknod %s (%d,%d) %o"
751 " %u:%u",
752 node_name, major, minor, rule->mode | type,
753 rule->ugid.uid, rule->ugid.gid
754 );
755 } else {
756 dbg1("mknod %s (%d,%d) %o",
757 node_name, major, minor, rule->mode | type
758 );
759 }
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);
765 }
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);
775 }
776 }
777 }
778
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);
782 putenv(s);
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);
787 }
788
789 if (operation == OP_remove && major >= -1) {
790 if (ENABLE_FEATURE_MDEV_RENAME && alias) {
791 if (aliaslink == '>') {
792 dbg1("unlink: %s", device_name);
793 unlink(device_name);
794 }
795 }
796 dbg1("unlink: %s", node_name);
797 unlink(node_name);
798 }
799
800 if (ENABLE_FEATURE_MDEV_RENAME)
801 free(alias);
802
803 /* We found matching line.
804 * Stop unless it was prefixed with '-'
805 */
806 if (!ENABLE_FEATURE_MDEV_CONF || !rule->keep_matching)
807 break;
808 } /* for (;;) */
809}
810
811/* File callback for /sys/ traversal */
812static int FAST_FUNC fileAction(const char *fileName,
813 struct stat *statbuf UNUSED_PARAM,
814 void *userData,
815 int depth UNUSED_PARAM)
816{
817 size_t len = strlen(fileName) - 4; /* can't underflow */
818 char *scratch = userData;
819
820 /* len check is for paranoid reasons */
821 if (strcmp(fileName + len, "/dev") != 0 || len >= PATH_MAX)
822 return FALSE;
823
824 strcpy(scratch, fileName);
825 scratch[len] = '\0';
826 make_device(/*DEVNAME:*/ NULL, scratch, OP_add);
827
828 return TRUE;
829}
830
831/* Directory callback for /sys/ traversal */
832static int FAST_FUNC dirAction(const char *fileName UNUSED_PARAM,
833 struct stat *statbuf UNUSED_PARAM,
834 void *userData UNUSED_PARAM,
835 int depth)
836{
837 /* Extract device subsystem -- the name of the directory
838 * under /sys/class/ */
839 if (1 == depth) {
840 free(G.subsystem);
841 if (G.subsys_env) {
842 bb_unsetenv_and_free(G.subsys_env);
843 G.subsys_env = NULL;
844 }
845 G.subsystem = strrchr(fileName, '/');
846 if (G.subsystem) {
847 G.subsystem = xstrdup(G.subsystem + 1);
848 G.subsys_env = xasprintf("%s=%s", "SUBSYSTEM", G.subsystem);
849 putenv(G.subsys_env);
850 }
851 }
852
853 return (depth >= MAX_SYSFS_DEPTH ? SKIP : TRUE);
854}
855
856/* For the full gory details, see linux/Documentation/firmware_class/README
857 *
858 * Firmware loading works like this:
859 * - kernel sets FIRMWARE env var
860 * - userspace checks /lib/firmware/$FIRMWARE
861 * - userspace waits for /sys/$DEVPATH/loading to appear
862 * - userspace writes "1" to /sys/$DEVPATH/loading
863 * - userspace copies /lib/firmware/$FIRMWARE into /sys/$DEVPATH/data
864 * - userspace writes "0" (worked) or "-1" (failed) to /sys/$DEVPATH/loading
865 * - kernel loads firmware into device
866 */
867static void load_firmware(const char *firmware, const char *sysfs_path)
868{
869 int cnt;
870 int firmware_fd, loading_fd;
871
872 /* check for /lib/firmware/$FIRMWARE */
873 xchdir("/lib/firmware");
874 firmware_fd = open(firmware, O_RDONLY); /* can fail */
875
876 /* check for /sys/$DEVPATH/loading ... give 30 seconds to appear */
877 xchdir(sysfs_path);
878 for (cnt = 0; cnt < 30; ++cnt) {
879 loading_fd = open("loading", O_WRONLY);
880 if (loading_fd >= 0)
881 goto loading;
882 sleep(1);
883 }
884 goto out;
885
886 loading:
887 cnt = 0;
888 if (firmware_fd >= 0) {
889 int data_fd;
890
891 /* tell kernel we're loading by "echo 1 > /sys/$DEVPATH/loading" */
892 if (full_write(loading_fd, "1", 1) != 1)
893 goto out;
894
895 /* load firmware into /sys/$DEVPATH/data */
896 data_fd = open("data", O_WRONLY);
897 if (data_fd < 0)
898 goto out;
899 cnt = bb_copyfd_eof(firmware_fd, data_fd);
900 if (ENABLE_FEATURE_CLEAN_UP)
901 close(data_fd);
902 }
903
904 /* Tell kernel result by "echo [0|-1] > /sys/$DEVPATH/loading"
905 * Note: we emit -1 also if firmware file wasn't found.
906 * There are cases when otherwise kernel would wait for minutes
907 * before timing out.
908 */
909 if (cnt > 0)
910 full_write(loading_fd, "0", 1);
911 else
912 full_write(loading_fd, "-1", 2);
913
914 out:
915 xchdir("/dev");
916 if (ENABLE_FEATURE_CLEAN_UP) {
917 close(firmware_fd);
918 close(loading_fd);
919 }
920}
921
922static char *curtime(void)
923{
924 struct timeval tv;
925 gettimeofday(&tv, NULL);
926 sprintf(G.timestr, "%u.%06u", (unsigned)tv.tv_sec % 60, (unsigned)tv.tv_usec);
927 return G.timestr;
928}
929
930static void open_mdev_log(const char *seq, unsigned my_pid)
931{
932 int logfd = open("mdev.log", O_WRONLY | O_APPEND);
933 if (logfd >= 0) {
934 xmove_fd(logfd, STDERR_FILENO);
935 G.verbose = 2;
936 applet_name = xasprintf("%s[%s]", applet_name, seq ? seq : utoa(my_pid));
937 }
938}
939
940/* If it exists, does /dev/mdev.seq match $SEQNUM?
941 * If it does not match, earlier mdev is running
942 * in parallel, and we need to wait.
943 * Active mdev pokes us with SIGCHLD to check the new file.
944 */
945static int
946wait_for_seqfile(const char *seq)
947{
948 /* We time out after 2 sec */
949 static const struct timespec ts = { 0, 32*1000*1000 };
950 int timeout = 2000 / 32;
951 int seq_fd = -1;
952 int do_once = 1;
953 sigset_t set_CHLD;
954
955 sigemptyset(&set_CHLD);
956 sigaddset(&set_CHLD, SIGCHLD);
957 sigprocmask(SIG_BLOCK, &set_CHLD, NULL);
958
959 for (;;) {
960 int seqlen;
961 char seqbuf[sizeof(int)*3 + 2];
962
963 if (seq_fd < 0) {
964 seq_fd = open("mdev.seq", O_RDWR);
965 if (seq_fd < 0)
966 break;
967 }
968 seqlen = pread(seq_fd, seqbuf, sizeof(seqbuf) - 1, 0);
969 if (seqlen < 0) {
970 close(seq_fd);
971 seq_fd = -1;
972 break;
973 }
974 seqbuf[seqlen] = '\0';
975 if (seqbuf[0] == '\n') {
976 /* seed file: write out seq ASAP */
977 xwrite_str(seq_fd, seq);
978 xlseek(seq_fd, 0, SEEK_SET);
979 dbg2("first seq written");
980 break;
981 }
982 if (strcmp(seq, seqbuf) == 0) {
983 /* correct idx */
984 break;
985 }
986 if (do_once) {
987 dbg2("%s waiting for '%s'", curtime(), seqbuf);
988 do_once = 0;
989 }
990 if (sigtimedwait(&set_CHLD, NULL, &ts) >= 0) {
991 dbg3("woken up");
992 continue; /* don't decrement timeout! */
993 }
994 if (--timeout == 0) {
995 dbg1("%s waiting for '%s'", "timed out", seqbuf);
996 break;
997 }
998 }
999 sigprocmask(SIG_UNBLOCK, &set_CHLD, NULL);
1000 return seq_fd;
1001}
1002
1003static void signal_mdevs(unsigned my_pid)
1004{
1005 procps_status_t* p = NULL;
1006 while ((p = procps_scan(p, PSSCAN_ARGV0)) != NULL) {
1007 if (p->pid != my_pid
1008 && p->argv0
1009 && strcmp(bb_basename(p->argv0), "mdev") == 0
1010 ) {
1011 kill(p->pid, SIGCHLD);
1012 }
1013 }
1014}
1015
1016int mdev_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
1017int mdev_main(int argc UNUSED_PARAM, char **argv)
1018{
1019 RESERVE_CONFIG_BUFFER(temp, PATH_MAX + SCRATCH_SIZE);
1020
1021 INIT_G();
1022
1023#if ENABLE_FEATURE_MDEV_CONF
1024 G.filename = "/etc/mdev.conf";
1025#endif
1026
1027 /* We can be called as hotplug helper */
1028 /* Kernel cannot provide suitable stdio fds for us, do it ourself */
1029 bb_sanitize_stdio();
1030
1031 /* Force the configuration file settings exactly */
1032 umask(0);
1033
1034 xchdir("/dev");
1035
1036 if (argv[1] && strcmp(argv[1], "-s") == 0) {
1037 /*
1038 * Scan: mdev -s
1039 */
1040 struct stat st;
1041
1042#if ENABLE_FEATURE_MDEV_CONF
1043 /* Same as xrealloc_vector(NULL, 4, 0): */
1044 G.rule_vec = xzalloc((1 << 4) * sizeof(*G.rule_vec));
1045#endif
1046 xstat("/", &st);
1047 G.root_major = major(st.st_dev);
1048 G.root_minor = minor(st.st_dev);
1049
1050 putenv((char*)"ACTION=add");
1051
1052 /* ACTION_FOLLOWLINKS is needed since in newer kernels
1053 * /sys/block/loop* (for example) are symlinks to dirs,
1054 * not real directories.
1055 * (kernel's CONFIG_SYSFS_DEPRECATED makes them real dirs,
1056 * but we can't enforce that on users)
1057 */
1058 if (access("/sys/class/block", F_OK) != 0) {
1059 /* Scan obsolete /sys/block only if /sys/class/block
1060 * doesn't exist. Otherwise we'll have dupes.
1061 * Also, do not complain if it doesn't exist.
1062 * Some people configure kernel to have no blockdevs.
1063 */
1064 recursive_action("/sys/block",
1065 ACTION_RECURSE | ACTION_FOLLOWLINKS | ACTION_QUIET,
1066 fileAction, dirAction, temp, 0);
1067 }
1068 recursive_action("/sys/class",
1069 ACTION_RECURSE | ACTION_FOLLOWLINKS,
1070 fileAction, dirAction, temp, 0);
1071 } else {
1072 char *fw;
1073 char *seq;
1074 char *action;
1075 char *env_devname;
1076 char *env_devpath;
1077 unsigned my_pid;
1078 int seq_fd;
1079 smalluint op;
1080
1081 /* Hotplug:
1082 * env ACTION=... DEVPATH=... SUBSYSTEM=... [SEQNUM=...] mdev
1083 * ACTION can be "add", "remove", "change"
1084 * DEVPATH is like "/block/sda" or "/class/input/mice"
1085 */
1086 env_devname = getenv("DEVNAME"); /* can be NULL */
1087 G.subsystem = getenv("SUBSYSTEM");
1088 action = getenv("ACTION");
1089 env_devpath = getenv("DEVPATH");
1090 if (!action || !env_devpath /*|| !G.subsystem*/)
1091 bb_show_usage();
1092 fw = getenv("FIRMWARE");
1093 seq = getenv("SEQNUM");
1094 op = index_in_strings(keywords, action);
1095
1096 my_pid = getpid();
1097 open_mdev_log(seq, my_pid);
1098
1099 seq_fd = seq ? wait_for_seqfile(seq) : -1;
1100
1101 dbg1("%s "
1102 "ACTION:%s SUBSYSTEM:%s DEVNAME:%s DEVPATH:%s"
1103 "%s%s",
1104 curtime(),
1105 action, G.subsystem, env_devname, env_devpath,
1106 fw ? " FW:" : "", fw ? fw : ""
1107 );
1108
1109 snprintf(temp, PATH_MAX, "/sys%s", env_devpath);
1110 if (op == OP_remove) {
1111 /* Ignoring "remove firmware". It was reported
1112 * to happen and to cause erroneous deletion
1113 * of device nodes. */
1114 if (!fw)
1115 make_device(env_devname, temp, op);
1116 }
1117 else {
1118 make_device(env_devname, temp, op);
1119 if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE) {
1120 if (op == OP_add && fw)
1121 load_firmware(fw, temp);
1122 }
1123 }
1124
1125 dbg1("%s exiting", curtime());
1126 if (seq_fd >= 0) {
1127 xwrite_str(seq_fd, utoa(xatou(seq) + 1));
1128 signal_mdevs(my_pid);
1129 }
1130 }
1131
1132 if (ENABLE_FEATURE_CLEAN_UP)
1133 RELEASE_CONFIG_BUFFER(temp);
1134
1135 return EXIT_SUCCESS;
1136}
1137
generated by cgit at 2024-05-15 23:06:28 (GMT)