util-linux/mdev.c

   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-$(CONFIG_MDEV) += mdev.o
  72
  73 //usage:#define mdev_trivial_usage
  74 //usage:       "[-s]"
  75 //usage:#define mdev_full_usage "\n\n"
  76 //usage:       "mdev -s is to be run during boot to scan /sys and populate /dev.\n"
  77 //usage:       "\n"
  78 //usage:       "Bare mdev is a kernel hotplug helper. To activate it:\n"
  79 //usage:       "        echo /sbin/mdev >/proc/sys/kernel/hotplug\n"
  80 //usage:        IF_FEATURE_MDEV_CONF(
  81 //usage:       "\n"
  82 //usage:       "It uses /etc/mdev.conf with lines\n"
  83 //usage:       "        [-]DEVNAME UID:GID PERM"
  84 //usage:                        IF_FEATURE_MDEV_RENAME(" [>|=PATH]|[!]")
  85 //usage:                        IF_FEATURE_MDEV_EXEC(" [@|$|*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 static const char keywords[] ALIGN1 = "add\0remove\0change\0";
 234 enum { OP_add, OP_remove };
 235
 236 struct rule {
 237         bool keep_matching;
 238         bool regex_compiled;
 239         mode_t mode;
 240         int maj, min0, min1;
 241         struct bb_uidgid_t ugid;
 242         char *envvar;
 243         char *ren_mov;
 244         IF_FEATURE_MDEV_EXEC(char *r_cmd;)
 245         regex_t match;
 246 };
 247
 248 struct globals {
 249         int root_major, root_minor;
 250         smallint verbose;
 251         char *subsystem;
 252 #if ENABLE_FEATURE_MDEV_CONF
 253         const char *filename;
 254         parser_t *parser;
 255         struct rule **rule_vec;
 256         unsigned rule_idx;
 257 #endif
 258         struct rule cur_rule;
 259 } FIX_ALIASING;
 260 #define G (*(struct globals*)&bb_common_bufsiz1)
 261 #define INIT_G() do { \
 262         IF_NOT_FEATURE_MDEV_CONF(G.cur_rule.maj = -1;) \
 263         IF_NOT_FEATURE_MDEV_CONF(G.cur_rule.mode = 0660;) \
 264 } while (0)
 265
 266
 267 /* Prevent infinite loops in /sys symlinks */
 268 #define MAX_SYSFS_DEPTH 3
 269
 270 /* We use additional 64+ bytes in make_device() */
 271 #define SCRATCH_SIZE 80
 272
 273 #if 0
 274 # define dbg(...) bb_error_msg(__VA_ARGS__)
 275 #else
 276 # define dbg(...) ((void)0)
 277 #endif
 278
 279
 280 #if ENABLE_FEATURE_MDEV_CONF
 281
 282 static void make_default_cur_rule(void)
 283 {
 284         memset(&G.cur_rule, 0, sizeof(G.cur_rule));
 285         G.cur_rule.maj = -1; /* "not a @major,minor rule" */
 286         G.cur_rule.mode = 0660;
 287 }
 288
 289 static void clean_up_cur_rule(void)
 290 {
 291         free(G.cur_rule.envvar);
 292         if (G.cur_rule.regex_compiled)
 293                 regfree(&G.cur_rule.match);
 294         free(G.cur_rule.ren_mov);
 295         IF_FEATURE_MDEV_EXEC(free(G.cur_rule.r_cmd);)
 296         make_default_cur_rule();
 297 }
 298
 299 static void parse_next_rule(void)
 300 {
 301         /* Note: on entry, G.cur_rule is set to default */
 302         while (1) {
 303                 char *tokens[4];
 304                 char *val;
 305
 306                 /* No PARSE_EOL_COMMENTS, because command may contain '#' chars */
 307                 if (!config_read(G.parser, tokens, 4, 3, "# \t", PARSE_NORMAL & ~PARSE_EOL_COMMENTS))
 308                         break;
 309
 310                 /* Fields: [-]regex uid:gid mode [alias] [cmd] */
 311                 dbg("token1:'%s'", tokens[1]);
 312
 313                 /* 1st field */
 314                 val = tokens[0];
 315                 G.cur_rule.keep_matching = ('-' == val[0]);
 316                 val += G.cur_rule.keep_matching; /* swallow leading dash */
 317                 if (val[0] == '@') {
 318                         /* @major,minor[-minor2] */
 319                         /* (useful when name is ambiguous:
 320                          * "/sys/class/usb/lp0" and
 321                          * "/sys/class/printer/lp0")
 322                          */
 323                         int sc = sscanf(val, "@%u,%u-%u", &G.cur_rule.maj, &G.cur_rule.min0, &G.cur_rule.min1);
 324                         if (sc < 2 || G.cur_rule.maj < 0) {
 325                                 bb_error_msg("bad @maj,min on line %d", G.parser->lineno);
 326                                 goto next_rule;
 327                         }
 328                         if (sc == 2)
 329                                 G.cur_rule.min1 = G.cur_rule.min0;
 330                 } else {
 331                         if (val[0] == '$') {
 332                                 char *eq = strchr(++val, '=');
 333                                 if (!eq) {
 334                                         bb_error_msg("bad $envvar=regex on line %d", G.parser->lineno);
 335                                         goto next_rule;
 336                                 }
 337                                 G.cur_rule.envvar = xstrndup(val, eq - val);
 338                                 val = eq + 1;
 339                         }
 340                         xregcomp(&G.cur_rule.match, val, REG_EXTENDED);
 341                         G.cur_rule.regex_compiled = 1;
 342                 }
 343
 344                 /* 2nd field: uid:gid - device ownership */
 345                 if (get_uidgid(&G.cur_rule.ugid, tokens[1], /*allow_numeric:*/ 1) == 0) {
 346                         bb_error_msg("unknown user/group '%s' on line %d", tokens[1], G.parser->lineno);
 347                         goto next_rule;
 348                 }
 349
 350                 /* 3rd field: mode - device permissions */
 351                 bb_parse_mode(tokens[2], &G.cur_rule.mode);
 352
 353                 /* 4th field (opt): ">|=alias" or "!" to not create the node */
 354                 val = tokens[3];
 355                 if (ENABLE_FEATURE_MDEV_RENAME && val && strchr(">=!", val[0])) {
 356                         char *s = skip_non_whitespace(val);
 357                         G.cur_rule.ren_mov = xstrndup(val, s - val);
 358                         val = skip_whitespace(s);
 359                 }
 360
 361                 if (ENABLE_FEATURE_MDEV_EXEC && val && val[0]) {
 362                         const char *s = "$@*";
 363                         const char *s2 = strchr(s, val[0]);
 364                         if (!s2) {
 365                                 bb_error_msg("bad line %u", G.parser->lineno);
 366                                 goto next_rule;
 367                         }
 368                         IF_FEATURE_MDEV_EXEC(G.cur_rule.r_cmd = xstrdup(val);)
 369                 }
 370
 371                 return;
 372  next_rule:
 373                 clean_up_cur_rule();
 374         } /* while (config_read) */
 375
 376         dbg("config_close(G.parser)");
 377         config_close(G.parser);
 378         G.parser = NULL;
 379
 380         return;
 381 }
 382
 383 /* If mdev -s, we remember rules in G.rule_vec[].
 384  * Otherwise, there is no point in doing it, and we just
 385  * save only one parsed rule in G.cur_rule.
 386  */
 387 static const struct rule *next_rule(void)
 388 {
 389         struct rule *rule;
 390
 391         /* Open conf file if we didn't do it yet */
 392         if (!G.parser && G.filename) {
 393                 dbg("config_open('%s')", G.filename);
 394                 G.parser = config_open2(G.filename, fopen_for_read);
 395                 G.filename = NULL;
 396         }
 397
 398         if (G.rule_vec) {
 399                 /* mdev -s */
 400                 /* Do we have rule parsed already? */
 401                 if (G.rule_vec[G.rule_idx]) {
 402                         dbg("< G.rule_vec[G.rule_idx:%d]=%p", G.rule_idx, G.rule_vec[G.rule_idx]);
 403                         return G.rule_vec[G.rule_idx++];
 404                 }
 405                 make_default_cur_rule();
 406         } else {
 407                 /* not mdev -s */
 408                 clean_up_cur_rule();
 409         }
 410
 411         /* Parse one more rule if file isn't fully read */
 412         rule = &G.cur_rule;
 413         if (G.parser) {
 414                 parse_next_rule();
 415                 if (G.rule_vec) { /* mdev -s */
 416                         rule = memcpy(xmalloc(sizeof(G.cur_rule)), &G.cur_rule, sizeof(G.cur_rule));
 417                         G.rule_vec = xrealloc_vector(G.rule_vec, 4, G.rule_idx);
 418                         G.rule_vec[G.rule_idx++] = rule;
 419                         dbg("> G.rule_vec[G.rule_idx:%d]=%p", G.rule_idx, G.rule_vec[G.rule_idx]);
 420                 }
 421         }
 422
 423         return rule;
 424 }
 425
 426 #else
 427
 428 # define next_rule() (&G.cur_rule)
 429
 430 #endif
 431
 432 /* Builds an alias path.
 433  * This function potentionally reallocates the alias parameter.
 434  * Only used for ENABLE_FEATURE_MDEV_RENAME
 435  */
 436 static char *build_alias(char *alias, const char *device_name)
 437 {
 438         char *dest;
 439
 440         /* ">bar/": rename to bar/device_name */
 441         /* ">bar[/]baz": rename to bar[/]baz */
 442         dest = strrchr(alias, '/');
 443         if (dest) { /* ">bar/[baz]" ? */
 444                 *dest = '\0'; /* mkdir bar */
 445                 bb_make_directory(alias, 0755, FILEUTILS_RECUR);
 446                 *dest = '/';
 447                 if (dest[1] == '\0') { /* ">bar/" => ">bar/device_name" */
 448                         dest = alias;
 449                         alias = concat_path_file(alias, device_name);
 450                         free(dest);
 451                 }
 452         }
 453
 454         return alias;
 455 }
 456
 457 /* mknod in /dev based on a path like "/sys/block/hda/hda1"
 458  * NB1: path parameter needs to have SCRATCH_SIZE scratch bytes
 459  * after NUL, but we promise to not mangle (IOW: to restore if needed)
 460  * path string.
 461  * NB2: "mdev -s" may call us many times, do not leak memory/fds!
 462  *
 463  * device_name = $DEVNAME (may be NULL)
 464  * path        = /sys/$DEVPATH
 465  */
 466 static void make_device(char *device_name, char *path, int operation)
 467 {
 468         int major, minor, type, len;
 469
 470         if (G.verbose)
 471                 bb_error_msg("device: %s, %s", device_name, path);
 472
 473         /* Try to read major/minor string.  Note that the kernel puts \n after
 474          * the data, so we don't need to worry about null terminating the string
 475          * because sscanf() will stop at the first nondigit, which \n is.
 476          * We also depend on path having writeable space after it.
 477          */
 478         major = -1;
 479         if (operation == OP_add) {
 480                 char *dev_maj_min = path + strlen(path);
 481
 482                 strcpy(dev_maj_min, "/dev");
 483                 len = open_read_close(path, dev_maj_min + 1, 64);
 484                 *dev_maj_min = '\0';
 485                 if (len < 1) {
 486                         if (!ENABLE_FEATURE_MDEV_EXEC)
 487                                 return;
 488                         /* no "dev" file, but we can still run scripts
 489                          * based on device name */
 490                 } else if (sscanf(++dev_maj_min, "%u:%u", &major, &minor) == 2) {
 491                         if (G.verbose)
 492                                 bb_error_msg("maj,min: %u,%u", major, minor);
 493                 } else {
 494                         major = -1;
 495                 }
 496         }
 497         /* else: for delete, -1 still deletes the node, but < -1 suppresses that */
 498
 499         /* Determine device name, type, major and minor */
 500         if (!device_name)
 501                 device_name = (char*) bb_basename(path);
 502         /* http://kernel.org/doc/pending/hotplug.txt says that only
 503          * "/sys/block/..." is for block devices. "/sys/bus" etc is not.
 504          * But since 2.6.25 block devices are also in /sys/class/block.
 505          * We use strstr("/block/") to forestall future surprises.
 506          */
 507         type = S_IFCHR;
 508         if (strstr(path, "/block/") || (G.subsystem && strncmp(G.subsystem, "block", 5) == 0))
 509                 type = S_IFBLK;
 510
 511 #if ENABLE_FEATURE_MDEV_CONF
 512         G.rule_idx = 0; /* restart from the beginning (think mdev -s) */
 513 #endif
 514         for (;;) {
 515                 const char *str_to_match;
 516                 regmatch_t off[1 + 9 * ENABLE_FEATURE_MDEV_RENAME_REGEXP];
 517                 char *command;
 518                 char *alias;
 519                 char aliaslink = aliaslink; /* for compiler */
 520                 char *node_name;
 521                 const struct rule *rule;
 522
 523                 str_to_match = device_name;
 524
 525                 rule = next_rule();
 526
 527 #if ENABLE_FEATURE_MDEV_CONF
 528                 if (rule->maj >= 0) {  /* @maj,min rule */
 529                         if (major != rule->maj)
 530                                 continue;
 531                         if (minor < rule->min0 || minor > rule->min1)
 532                                 continue;
 533                         memset(off, 0, sizeof(off));
 534                         goto rule_matches;
 535                 }
 536                 if (rule->envvar) { /* $envvar=regex rule */
 537                         str_to_match = getenv(rule->envvar);
 538                         dbg("getenv('%s'):'%s'", rule->envvar, str_to_match);
 539                         if (!str_to_match)
 540                                 continue;
 541                 }
 542                 /* else: str_to_match = device_name */
 543
 544                 if (rule->regex_compiled) {
 545                         int regex_match = regexec(&rule->match, str_to_match, ARRAY_SIZE(off), off, 0);
 546                         dbg("regex_match for '%s':%d", str_to_match, regex_match);
 547                         //bb_error_msg("matches:");
 548                         //for (int i = 0; i < ARRAY_SIZE(off); i++) {
 549                         //      if (off[i].rm_so < 0) continue;
 550                         //      bb_error_msg("match %d: '%.*s'\n", i,
 551                         //              (int)(off[i].rm_eo - off[i].rm_so),
 552                         //              device_name + off[i].rm_so);
 553                         //}
 554
 555                         if (regex_match != 0
 556                         /* regexec returns whole pattern as "range" 0 */
 557                          || off[0].rm_so != 0
 558                          || (int)off[0].rm_eo != (int)strlen(str_to_match)
 559                         ) {
 560                                 continue; /* this rule doesn't match */
 561                         }
 562                 }
 563                 /* else: it's final implicit "match-all" rule */
 564  rule_matches:
 565 #endif
 566                 dbg("rule matched");
 567
 568                 /* Build alias name */
 569                 alias = NULL;
 570                 if (ENABLE_FEATURE_MDEV_RENAME && rule->ren_mov) {
 571                         aliaslink = rule->ren_mov[0];
 572                         if (aliaslink == '!') {
 573                                 /* "!": suppress node creation/deletion */
 574                                 major = -2;
 575                         }
 576                         else if (aliaslink == '>' || aliaslink == '=') {
 577                                 if (ENABLE_FEATURE_MDEV_RENAME_REGEXP) {
 578                                         char *s;
 579                                         char *p;
 580                                         unsigned n;
 581
 582                                         /* substitute %1..9 with off[1..9], if any */
 583                                         n = 0;
 584                                         s = rule->ren_mov;
 585                                         while (*s)
 586                                                 if (*s++ == '%')
 587                                                         n++;
 588
 589                                         p = alias = xzalloc(strlen(rule->ren_mov) + n * strlen(str_to_match));
 590                                         s = rule->ren_mov + 1;
 591                                         while (*s) {
 592                                                 *p = *s;
 593                                                 if ('%' == *s) {
 594                                                         unsigned i = (s[1] - '0');
 595                                                         if (i <= 9 && off[i].rm_so >= 0) {
 596                                                                 n = off[i].rm_eo - off[i].rm_so;
 597                                                                 strncpy(p, str_to_match + off[i].rm_so, n);
 598                                                                 p += n - 1;
 599                                                                 s++;
 600                                                         }
 601                                                 }
 602                                                 p++;
 603                                                 s++;
 604                                         }
 605                                 } else {
 606                                         alias = xstrdup(rule->ren_mov + 1);
 607                                 }
 608                         }
 609                 }
 610                 dbg("alias:'%s'", alias);
 611
 612                 command = NULL;
 613                 IF_FEATURE_MDEV_EXEC(command = rule->r_cmd;)
 614                 if (command) {
 615                         const char *s = "$@*";
 616                         const char *s2 = strchr(s, command[0]);
 617
 618                         /* Are we running this command now?
 619                          * Run $cmd on delete, @cmd on create, *cmd on both
 620                          */
 621                         if (s2 - s != (operation == OP_remove) || *s2 == '*') {
 622                                 /* We are here if: '*',
 623                                  * or: '@' and delete = 0,
 624                                  * or: '$' and delete = 1
 625                                  */
 626                                 command++;
 627                         } else {
 628                                 command = NULL;
 629                         }
 630                 }
 631                 dbg("command:'%s'", command);
 632
 633                 /* "Execute" the line we found */
 634                 node_name = device_name;
 635                 if (ENABLE_FEATURE_MDEV_RENAME && alias) {
 636                         node_name = alias = build_alias(alias, device_name);
 637                         dbg("alias2:'%s'", alias);
 638                 }
 639
 640                 if (operation == OP_add && major >= 0) {
 641                         char *slash = strrchr(node_name, '/');
 642                         if (slash) {
 643                                 *slash = '\0';
 644                                 bb_make_directory(node_name, 0755, FILEUTILS_RECUR);
 645                                 *slash = '/';
 646                         }
 647                         if (G.verbose)
 648                                 bb_error_msg("mknod: %s (%d,%d) %o", node_name, major, minor, rule->mode | type);
 649                         if (mknod(node_name, rule->mode | type, makedev(major, minor)) && errno != EEXIST)
 650                                 bb_perror_msg("can't create '%s'", node_name);
 651                         if (ENABLE_FEATURE_MDEV_CONF) {
 652                                 chmod(node_name, rule->mode);
 653                                 chown(node_name, rule->ugid.uid, rule->ugid.gid);
 654                         }
 655                         if (major == G.root_major && minor == G.root_minor)
 656                                 symlink(node_name, "root");
 657                         if (ENABLE_FEATURE_MDEV_RENAME && alias) {
 658                                 if (aliaslink == '>') {
 659 //TODO: on devtmpfs, device_name already exists and symlink() fails.
 660 //End result is that instead of symlink, we have two nodes.
 661 //What should be done?
 662                                         if (G.verbose)
 663                                                 bb_error_msg("symlink: %s", device_name);
 664                                         symlink(node_name, device_name);
 665                                 }
 666                         }
 667                 }
 668
 669                 if (ENABLE_FEATURE_MDEV_EXEC && command) {
 670                         /* setenv will leak memory, use putenv/unsetenv/free */
 671                         char *s = xasprintf("%s=%s", "MDEV", node_name);
 672                         char *s1 = xasprintf("%s=%s", "SUBSYSTEM", G.subsystem);
 673                         putenv(s);
 674                         putenv(s1);
 675                         if (G.verbose)
 676                                 bb_error_msg("running: %s", command);
 677                         if (system(command) == -1)
 678                                 bb_perror_msg("can't run '%s'", command);
 679                         bb_unsetenv_and_free(s1);
 680                         bb_unsetenv_and_free(s);
 681                 }
 682
 683                 if (operation == OP_remove && major >= -1) {
 684                         if (ENABLE_FEATURE_MDEV_RENAME && alias) {
 685                                 if (aliaslink == '>') {
 686                                         if (G.verbose)
 687                                                 bb_error_msg("unlink: %s", device_name);
 688                                         unlink(device_name);
 689                                 }
 690                         }
 691                         if (G.verbose)
 692                                 bb_error_msg("unlink: %s", node_name);
 693                         unlink(node_name);
 694                 }
 695
 696                 if (ENABLE_FEATURE_MDEV_RENAME)
 697                         free(alias);
 698
 699                 /* We found matching line.
 700                  * Stop unless it was prefixed with '-'
 701                  */
 702                 if (!ENABLE_FEATURE_MDEV_CONF || !rule->keep_matching)
 703                         break;
 704         } /* for (;;) */
 705 }
 706
 707 /* File callback for /sys/ traversal */
 708 static int FAST_FUNC fileAction(const char *fileName,
 709                 struct stat *statbuf UNUSED_PARAM,
 710                 void *userData,
 711                 int depth UNUSED_PARAM)
 712 {
 713         size_t len = strlen(fileName) - 4; /* can't underflow */
 714         char *scratch = userData;
 715
 716         /* len check is for paranoid reasons */
 717         if (strcmp(fileName + len, "/dev") != 0 || len >= PATH_MAX)
 718                 return FALSE;
 719
 720         strcpy(scratch, fileName);
 721         scratch[len] = '\0';
 722         make_device(/*DEVNAME:*/ NULL, scratch, OP_add);
 723
 724         return TRUE;
 725 }
 726
 727 /* Directory callback for /sys/ traversal */
 728 static int FAST_FUNC dirAction(const char *fileName UNUSED_PARAM,
 729                 struct stat *statbuf UNUSED_PARAM,
 730                 void *userData UNUSED_PARAM,
 731                 int depth)
 732 {
 733         /* Extract device subsystem -- the name of the directory
 734          * under /sys/class/ */
 735         if (1 == depth) {
 736                 free(G.subsystem);
 737                 G.subsystem = strrchr(fileName, '/');
 738                 if (G.subsystem)
 739                         G.subsystem = xstrdup(G.subsystem + 1);
 740         }
 741
 742         return (depth >= MAX_SYSFS_DEPTH ? SKIP : TRUE);
 743 }
 744
 745 /* For the full gory details, see linux/Documentation/firmware_class/README
 746  *
 747  * Firmware loading works like this:
 748  * - kernel sets FIRMWARE env var
 749  * - userspace checks /lib/firmware/$FIRMWARE
 750  * - userspace waits for /sys/$DEVPATH/loading to appear
 751  * - userspace writes "1" to /sys/$DEVPATH/loading
 752  * - userspace copies /lib/firmware/$FIRMWARE into /sys/$DEVPATH/data
 753  * - userspace writes "0" (worked) or "-1" (failed) to /sys/$DEVPATH/loading
 754  * - kernel loads firmware into device
 755  */
 756 static void load_firmware(const char *firmware, const char *sysfs_path)
 757 {
 758         int cnt;
 759         int firmware_fd, loading_fd;
 760
 761         /* check for /lib/firmware/$FIRMWARE */
 762         xchdir("/lib/firmware");
 763         firmware_fd = open(firmware, O_RDONLY); /* can fail */
 764
 765         /* check for /sys/$DEVPATH/loading ... give 30 seconds to appear */
 766         xchdir(sysfs_path);
 767         for (cnt = 0; cnt < 30; ++cnt) {
 768                 loading_fd = open("loading", O_WRONLY);
 769                 if (loading_fd >= 0)
 770                         goto loading;
 771                 sleep(1);
 772         }
 773         goto out;
 774
 775  loading:
 776         cnt = 0;
 777         if (firmware_fd >= 0) {
 778                 int data_fd;
 779
 780                 /* tell kernel we're loading by "echo 1 > /sys/$DEVPATH/loading" */
 781                 if (full_write(loading_fd, "1", 1) != 1)
 782                         goto out;
 783
 784                 /* load firmware into /sys/$DEVPATH/data */
 785                 data_fd = open("data", O_WRONLY);
 786                 if (data_fd < 0)
 787                         goto out;
 788                 cnt = bb_copyfd_eof(firmware_fd, data_fd);
 789                 if (ENABLE_FEATURE_CLEAN_UP)
 790                         close(data_fd);
 791         }
 792
 793         /* Tell kernel result by "echo [0|-1] > /sys/$DEVPATH/loading"
 794          * Note: we emit -1 also if firmware file wasn't found.
 795          * There are cases when otherwise kernel would wait for minutes
 796          * before timing out.
 797          */
 798         if (cnt > 0)
 799                 full_write(loading_fd, "0", 1);
 800         else
 801                 full_write(loading_fd, "-1", 2);
 802
 803  out:
 804         if (ENABLE_FEATURE_CLEAN_UP) {
 805                 close(firmware_fd);
 806                 close(loading_fd);
 807         }
 808 }
 809
 810 int mdev_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 811 int mdev_main(int argc UNUSED_PARAM, char **argv)
 812 {
 813         RESERVE_CONFIG_BUFFER(temp, PATH_MAX + SCRATCH_SIZE);
 814
 815         INIT_G();
 816
 817 #if ENABLE_FEATURE_MDEV_CONF
 818         G.filename = "/etc/mdev.conf";
 819 #endif
 820
 821         /* We can be called as hotplug helper */
 822         /* Kernel cannot provide suitable stdio fds for us, do it ourself */
 823         bb_sanitize_stdio();
 824
 825         /* Force the configuration file settings exactly */
 826         umask(0);
 827
 828         xchdir("/dev");
 829
 830         if (argv[1] && strcmp(argv[1], "-s") == 0) {
 831                 /* Scan:
 832                  * mdev -s
 833                  */
 834                 struct stat st;
 835
 836 #if ENABLE_FEATURE_MDEV_CONF
 837                 /* Same as xrealloc_vector(NULL, 4, 0): */
 838                 G.rule_vec = xzalloc((1 << 4) * sizeof(*G.rule_vec));
 839 #endif
 840                 xstat("/", &st);
 841                 G.root_major = major(st.st_dev);
 842                 G.root_minor = minor(st.st_dev);
 843
 844                 /* ACTION_FOLLOWLINKS is needed since in newer kernels
 845                  * /sys/block/loop* (for example) are symlinks to dirs,
 846                  * not real directories.
 847                  * (kernel's CONFIG_SYSFS_DEPRECATED makes them real dirs,
 848                  * but we can't enforce that on users)
 849                  */
 850                 if (access("/sys/class/block", F_OK) != 0) {
 851                         /* Scan obsolete /sys/block only if /sys/class/block
 852                          * doesn't exist. Otherwise we'll have dupes.
 853                          * Also, do not complain if it doesn't exist.
 854                          * Some people configure kernel to have no blockdevs.
 855                          */
 856                         recursive_action("/sys/block",
 857                                 ACTION_RECURSE | ACTION_FOLLOWLINKS | ACTION_QUIET,
 858                                 fileAction, dirAction, temp, 0);
 859                 }
 860                 recursive_action("/sys/class",
 861                         ACTION_RECURSE | ACTION_FOLLOWLINKS,
 862                         fileAction, dirAction, temp, 0);
 863         } else {
 864                 char *fw;
 865                 char *seq;
 866                 char *action;
 867                 char *env_devname;
 868                 char *env_devpath;
 869                 smalluint op;
 870
 871                 /* Hotplug:
 872                  * env ACTION=... DEVPATH=... SUBSYSTEM=... [SEQNUM=...] mdev
 873                  * ACTION can be "add" or "remove"
 874                  * DEVPATH is like "/block/sda" or "/class/input/mice"
 875                  */
 876                 action = getenv("ACTION");
 877                 op = index_in_strings(keywords, action);
 878                 env_devname = getenv("DEVNAME"); /* can be NULL */
 879                 env_devpath = getenv("DEVPATH");
 880                 G.subsystem = getenv("SUBSYSTEM");
 881                 if (!action || !env_devpath /*|| !G.subsystem*/)
 882                         bb_show_usage();
 883                 fw = getenv("FIRMWARE");
 884                 /* If it exists, does /dev/mdev.seq match $SEQNUM?
 885                  * If it does not match, earlier mdev is running
 886                  * in parallel, and we need to wait */
 887                 seq = getenv("SEQNUM");
 888                 if (seq) {
 889                         int timeout = 2000 / 32; /* 2000 msec */
 890                         do {
 891                                 int seqlen;
 892                                 char seqbuf[sizeof(int)*3 + 2];
 893
 894                                 seqlen = open_read_close("mdev.seq", seqbuf, sizeof(seqbuf) - 1);
 895                                 if (seqlen < 0) {
 896                                         seq = NULL;
 897                                         break;
 898                                 }
 899                                 seqbuf[seqlen] = '\0';
 900                                 if (seqbuf[0] == '\n' /* seed file? */
 901                                  || strcmp(seq, seqbuf) == 0 /* correct idx? */
 902                                 ) {
 903                                         break;
 904                                 }
 905                                 usleep(32*1000);
 906                         } while (--timeout);
 907                 }
 908
 909                 {
 910                         int logfd = open("/dev/mdev.log", O_WRONLY | O_APPEND);
 911                         if (logfd >= 0) {
 912                                 xmove_fd(logfd, STDERR_FILENO);
 913                                 G.verbose = 1;
 914                                 bb_error_msg("seq: %s action: %s", seq, action);
 915                         }
 916                 }
 917
 918                 snprintf(temp, PATH_MAX, "/sys%s", env_devpath);
 919                 if (op == OP_remove) {
 920                         /* Ignoring "remove firmware". It was reported
 921                          * to happen and to cause erroneous deletion
 922                          * of device nodes. */
 923                         if (!fw)
 924                                 make_device(env_devname, temp, op);
 925                 }
 926                 else if (op == OP_add) {
 927                         make_device(env_devname, temp, op);
 928                         if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE) {
 929                                 if (fw)
 930                                         load_firmware(fw, temp);
 931                         }
 932                 }
 933
 934                 if (seq) {
 935                         xopen_xwrite_close("mdev.seq", utoa(xatou(seq) + 1));
 936                 }
 937         }
 938
 939         if (ENABLE_FEATURE_CLEAN_UP)
 940                 RELEASE_CONFIG_BUFFER(temp);
 941
 942         return EXIT_SUCCESS;
 943 }