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 #include "libbb.h"
  11 #include "xregex.h"
  12
  13 /* "mdev -s" scans /sys/class/xxx, looking for directories which have dev
  14  * file (it is of the form "M:m\n"). Example: /sys/class/tty/tty0/dev
  15  * contains "4:0\n". Directory name is taken as device name, path component
  16  * directly after /sys/class/ as subsystem. In this example, "tty0" and "tty".
  17  * Then mdev creates the /dev/device_name node.
  18  * If /sys/class/.../dev file does not exist, mdev still may act
  19  * on this device: see "@|$|*command args..." parameter in config file.
  20  *
  21  * mdev w/o parameters is called as hotplug helper. It takes device
  22  * and subsystem names from $DEVPATH and $SUBSYSTEM, extracts
  23  * maj,min from "/sys/$DEVPATH/dev" and also examines
  24  * $ACTION ("add"/"delete") and $FIRMWARE.
  25  *
  26  * If action is "add", mdev creates /dev/device_name similarly to mdev -s.
  27  * (todo: explain "delete" and $FIRMWARE)
  28  *
  29  * If /etc/mdev.conf exists, it may modify /dev/device_name's properties.
  30  * /etc/mdev.conf file format:
  31  *
  32  * [-][subsystem/]device  user:grp  mode  [>|=path] [@|$|*command args...]
  33  * [-]@maj,min[-min2]     user:grp  mode  [>|=path] [@|$|*command args...]
  34  * [-]$envvar=val         user:grp  mode  [>|=path] [@|$|*command args...]
  35  *
  36  * Leading minus in 1st field means "don't stop on this line", otherwise
  37  * search is stopped after the matching line is encountered.
  38  *
  39  * The device name or "subsystem/device" combo is matched against 1st field
  40  * (which is a regex), or maj,min is matched against 1st field,
  41  * or specified environment variable (as regex) is matched against 1st field.
  42  *
  43  * $envvar=val format is useful for loading modules for hot-plugged devices
  44  * which do not have driver loaded yet. In this case /sys/class/.../dev
  45  * does not exist, but $MODALIAS is set to needed module's name
  46  * (actually, an alias to it) by kernel. This rule instructs mdev
  47  * to load the module and exit:
  48  *    $MODALIAS=.* 0:0 660 @modprobe "$MODALIAS"
  49  * The kernel will generate another hotplug event when /sys/class/.../dev
  50  * file appears.
  51  *
  52  * When line matches, the device node is created, chmod'ed and chown'ed,
  53  * moved to path, and if >path, a symlink to moved node is created,
  54  * all this if /sys/class/.../dev exists.
  55  *    Examples:
  56  *    =loop/      - moves to /dev/loop
  57  *    >disk/sda%1 - moves to /dev/disk/sdaN, makes /dev/sdaN a symlink
  58  *
  59  * Then "command args..." is executed (via sh -c 'command args...').
  60  * @:execute on creation, $:on deletion, *:on both.
  61  * This happens regardless of /sys/class/.../dev existence.
  62  */
  63
  64 struct globals {
  65         int root_major, root_minor;
  66         char *subsystem;
  67 } FIX_ALIASING;
  68 #define G (*(struct globals*)&bb_common_bufsiz1)
  69
  70 /* Prevent infinite loops in /sys symlinks */
  71 #define MAX_SYSFS_DEPTH 3
  72
  73 /* We use additional 64+ bytes in make_device() */
  74 #define SCRATCH_SIZE 80
  75
  76 /* Builds an alias path.
  77  * This function potentionally reallocates the alias parameter.
  78  * Only used for ENABLE_FEATURE_MDEV_RENAME
  79  */
  80 static char *build_alias(char *alias, const char *device_name)
  81 {
  82         char *dest;
  83
  84         /* ">bar/": rename to bar/device_name */
  85         /* ">bar[/]baz": rename to bar[/]baz */
  86         dest = strrchr(alias, '/');
  87         if (dest) { /* ">bar/[baz]" ? */
  88                 *dest = '\0'; /* mkdir bar */
  89                 bb_make_directory(alias, 0755, FILEUTILS_RECUR);
  90                 *dest = '/';
  91                 if (dest[1] == '\0') { /* ">bar/" => ">bar/device_name" */
  92                         dest = alias;
  93                         alias = concat_path_file(alias, device_name);
  94                         free(dest);
  95                 }
  96         }
  97
  98         return alias;
  99 }
 100
 101 /* mknod in /dev based on a path like "/sys/block/hda/hda1"
 102  * NB1: path parameter needs to have SCRATCH_SIZE scratch bytes
 103  * after NUL, but we promise to not mangle (IOW: to restore if needed)
 104  * path string.
 105  * NB2: "mdev -s" may call us many times, do not leak memory/fds!
 106  */
 107 static void make_device(char *path, int delete)
 108 {
 109         char *device_name, *subsystem_slash_devname;
 110         int major, minor, type, len;
 111         mode_t mode;
 112         parser_t *parser;
 113
 114         /* Try to read major/minor string.  Note that the kernel puts \n after
 115          * the data, so we don't need to worry about null terminating the string
 116          * because sscanf() will stop at the first nondigit, which \n is.
 117          * We also depend on path having writeable space after it.
 118          */
 119         major = -1;
 120         if (!delete) {
 121                 char *dev_maj_min = path + strlen(path);
 122
 123                 strcpy(dev_maj_min, "/dev");
 124                 len = open_read_close(path, dev_maj_min + 1, 64);
 125                 *dev_maj_min = '\0';
 126                 if (len < 1) {
 127                         if (!ENABLE_FEATURE_MDEV_EXEC)
 128                                 return;
 129                         /* no "dev" file, but we can still run scripts
 130                          * based on device name */
 131                 } else if (sscanf(++dev_maj_min, "%u:%u", &major, &minor) != 2) {
 132                         major = -1;
 133                 }
 134         }
 135         /* else: for delete, -1 still deletes the node, but < -1 suppresses that */
 136
 137         /* Determine device name, type, major and minor */
 138         device_name = (char*) bb_basename(path);
 139         /* http://kernel.org/doc/pending/hotplug.txt says that only
 140          * "/sys/block/..." is for block devices. "/sys/bus" etc is not.
 141          * But since 2.6.25 block devices are also in /sys/class/block.
 142          * We use strstr("/block/") to forestall future surprises. */
 143         type = S_IFCHR;
 144         if (strstr(path, "/block/") || (G.subsystem && strncmp(G.subsystem, "block", 5) == 0))
 145                 type = S_IFBLK;
 146
 147         /* Make path point to "subsystem/device_name" */
 148         subsystem_slash_devname = NULL;
 149         /* Check for coldplug invocations first */
 150         if (strncmp(path, "/sys/block/", 11) == 0) /* legacy case */
 151                 path += sizeof("/sys/") - 1;
 152         else if (strncmp(path, "/sys/class/", 11) == 0)
 153                 path += sizeof("/sys/class/") - 1;
 154         else {
 155                 /* Example of a hotplug invocation:
 156                  * SUBSYSTEM="block"
 157                  * DEVPATH="/sys" + "/devices/virtual/mtd/mtd3/mtdblock3"
 158                  * ("/sys" is added by mdev_main)
 159                  * - path does not contain subsystem
 160                  */
 161                 subsystem_slash_devname = concat_path_file(G.subsystem, device_name);
 162                 path = subsystem_slash_devname;
 163         }
 164
 165         /* If we have config file, look up user settings */
 166         if (ENABLE_FEATURE_MDEV_CONF)
 167                 parser = config_open2("/etc/mdev.conf", fopen_for_read);
 168
 169         do {
 170                 int keep_matching;
 171                 struct bb_uidgid_t ugid;
 172                 char *tokens[4];
 173                 char *command = NULL;
 174                 char *alias = NULL;
 175                 char aliaslink = aliaslink; /* for compiler */
 176
 177                 /* Defaults in case we won't match any line */
 178                 ugid.uid = ugid.gid = 0;
 179                 keep_matching = 0;
 180                 mode = 0660;
 181
 182                 if (ENABLE_FEATURE_MDEV_CONF
 183                  && config_read(parser, tokens, 4, 3, "# \t", PARSE_NORMAL)
 184                 ) {
 185                         char *val;
 186                         char *str_to_match;
 187                         regmatch_t off[1 + 9 * ENABLE_FEATURE_MDEV_RENAME_REGEXP];
 188
 189                         val = tokens[0];
 190                         keep_matching = ('-' == val[0]);
 191                         val += keep_matching; /* swallow leading dash */
 192
 193                         /* Match against either "subsystem/device_name"
 194                          * or "device_name" alone */
 195                         str_to_match = strchr(val, '/') ? path : device_name;
 196
 197                         /* Fields: regex uid:gid mode [alias] [cmd] */
 198
 199                         if (val[0] == '@') {
 200                                 /* @major,minor[-minor2] */
 201                                 /* (useful when name is ambiguous:
 202                                  * "/sys/class/usb/lp0" and
 203                                  * "/sys/class/printer/lp0") */
 204                                 int cmaj, cmin0, cmin1, sc;
 205                                 if (major < 0)
 206                                         continue; /* no dev, no match */
 207                                 sc = sscanf(val, "@%u,%u-%u", &cmaj, &cmin0, &cmin1);
 208                                 if (sc < 1
 209                                  || major != cmaj
 210                                  || (sc == 2 && minor != cmin0)
 211                                  || (sc == 3 && (minor < cmin0 || minor > cmin1))
 212                                 ) {
 213                                         continue; /* this line doesn't match */
 214                                 }
 215                                 goto line_matches;
 216                         }
 217                         if (val[0] == '$') {
 218                                 /* regex to match an environment variable */
 219                                 char *eq = strchr(++val, '=');
 220                                 if (!eq)
 221                                         continue;
 222                                 *eq = '\0';
 223                                 str_to_match = getenv(val);
 224                                 if (!str_to_match)
 225                                         continue;
 226                                 str_to_match -= strlen(val) + 1;
 227                                 *eq = '=';
 228                         }
 229                         /* else: regex to match [subsystem/]device_name */
 230
 231                         {
 232                                 regex_t match;
 233                                 int result;
 234
 235                                 xregcomp(&match, val, REG_EXTENDED);
 236                                 result = regexec(&match, str_to_match, ARRAY_SIZE(off), off, 0);
 237                                 regfree(&match);
 238                                 //bb_error_msg("matches:");
 239                                 //for (int i = 0; i < ARRAY_SIZE(off); i++) {
 240                                 //      if (off[i].rm_so < 0) continue;
 241                                 //      bb_error_msg("match %d: '%.*s'\n", i,
 242                                 //              (int)(off[i].rm_eo - off[i].rm_so),
 243                                 //              device_name + off[i].rm_so);
 244                                 //}
 245
 246                                 /* If no match, skip rest of line */
 247                                 /* (regexec returns whole pattern as "range" 0) */
 248                                 if (result
 249                                  || off[0].rm_so
 250                                  || ((int)off[0].rm_eo != (int)strlen(str_to_match))
 251                                 ) {
 252                                         continue; /* this line doesn't match */
 253                                 }
 254                         }
 255  line_matches:
 256                         /* This line matches. Stop parsing after parsing
 257                          * the rest the line unless keep_matching == 1 */
 258
 259                         /* 2nd field: uid:gid - device ownership */
 260                         if (get_uidgid(&ugid, tokens[1], 1) == 0)
 261                                 bb_error_msg("unknown user/group %s on line %d", tokens[1], parser->lineno);
 262
 263                         /* 3rd field: mode - device permissions */
 264                         bb_parse_mode(tokens[2], &mode);
 265
 266                         val = tokens[3];
 267                         /* 4th field (opt): ">|=alias" or "!" to not create the node */
 268
 269                         if (ENABLE_FEATURE_MDEV_RENAME && val) {
 270                                 char *a, *s, *st;
 271
 272                                 a = val;
 273                                 s = strchrnul(val, ' ');
 274                                 st = strchrnul(val, '\t');
 275                                 if (st < s)
 276                                         s = st;
 277                                 st = (s[0] && s[1]) ? s+1 : NULL;
 278
 279                                 aliaslink = a[0];
 280                                 if (aliaslink == '!' && s == a+1) {
 281                                         val = st;
 282                                         /* "!": suppress node creation/deletion */
 283                                         major = -2;
 284                                 }
 285                                 else if (aliaslink == '>' || aliaslink == '=') {
 286                                         val = st;
 287                                         s[0] = '\0';
 288                                         if (ENABLE_FEATURE_MDEV_RENAME_REGEXP) {
 289                                                 char *p;
 290                                                 unsigned i, n;
 291
 292                                                 /* substitute %1..9 with off[1..9], if any */
 293                                                 n = 0;
 294                                                 s = a;
 295                                                 while (*s)
 296                                                         if (*s++ == '%')
 297                                                                 n++;
 298
 299                                                 p = alias = xzalloc(strlen(a) + n * strlen(str_to_match));
 300                                                 s = a + 1;
 301                                                 while (*s) {
 302                                                         *p = *s;
 303                                                         if ('%' == *s) {
 304                                                                 i = (s[1] - '0');
 305                                                                 if (i <= 9 && off[i].rm_so >= 0) {
 306                                                                         n = off[i].rm_eo - off[i].rm_so;
 307                                                                         strncpy(p, str_to_match + off[i].rm_so, n);
 308                                                                         p += n - 1;
 309                                                                         s++;
 310                                                                 }
 311                                                         }
 312                                                         p++;
 313                                                         s++;
 314                                                 }
 315                                         } else {
 316                                                 alias = xstrdup(a + 1);
 317                                         }
 318                                 }
 319                         }
 320
 321                         if (ENABLE_FEATURE_MDEV_EXEC && val) {
 322                                 const char *s = "$@*";
 323                                 const char *s2 = strchr(s, val[0]);
 324
 325                                 if (!s2) {
 326                                         bb_error_msg("bad line %u", parser->lineno);
 327                                         if (ENABLE_FEATURE_MDEV_RENAME)
 328                                                 free(alias);
 329                                         continue;
 330                                 }
 331
 332                                 /* Are we running this command now?
 333                                  * Run $cmd on delete, @cmd on create, *cmd on both
 334                                  */
 335                                 if (s2 - s != delete) {
 336                                         /* We are here if: '*',
 337                                          * or: '@' and delete = 0,
 338                                          * or: '$' and delete = 1
 339                                          */
 340                                         command = xstrdup(val + 1);
 341                                 }
 342                         }
 343                 }
 344
 345                 /* End of field parsing */
 346
 347                 /* "Execute" the line we found */
 348                 {
 349                         const char *node_name;
 350
 351                         node_name = device_name;
 352                         if (ENABLE_FEATURE_MDEV_RENAME && alias)
 353                                 node_name = alias = build_alias(alias, device_name);
 354
 355                         if (!delete && major >= 0) {
 356                                 if (mknod(node_name, mode | type, makedev(major, minor)) && errno != EEXIST)
 357                                         bb_perror_msg("can't create '%s'", node_name);
 358                                 if (major == G.root_major && minor == G.root_minor)
 359                                         symlink(node_name, "root");
 360                                 if (ENABLE_FEATURE_MDEV_CONF) {
 361                                         chmod(node_name, mode);
 362                                         chown(node_name, ugid.uid, ugid.gid);
 363                                 }
 364                                 if (ENABLE_FEATURE_MDEV_RENAME && alias) {
 365                                         if (aliaslink == '>')
 366                                                 symlink(node_name, device_name);
 367                                 }
 368                         }
 369
 370                         if (ENABLE_FEATURE_MDEV_EXEC && command) {
 371                                 /* setenv will leak memory, use putenv/unsetenv/free */
 372                                 char *s = xasprintf("%s=%s", "MDEV", node_name);
 373                                 char *s1 = xasprintf("%s=%s", "SUBSYSTEM", G.subsystem);
 374                                 putenv(s);
 375                                 putenv(s1);
 376                                 if (system(command) == -1)
 377                                         bb_perror_msg("can't run '%s'", command);
 378                                 bb_unsetenv_and_free(s1);
 379                                 bb_unsetenv_and_free(s);
 380                                 free(command);
 381                         }
 382
 383                         if (delete && major >= -1) {
 384                                 if (ENABLE_FEATURE_MDEV_RENAME && alias) {
 385                                         if (aliaslink == '>')
 386                                                 unlink(device_name);
 387                                 }
 388                                 unlink(node_name);
 389                         }
 390
 391                         if (ENABLE_FEATURE_MDEV_RENAME)
 392                                 free(alias);
 393                 }
 394
 395                 /* We found matching line.
 396                  * Stop unless it was prefixed with '-' */
 397                 if (ENABLE_FEATURE_MDEV_CONF && !keep_matching)
 398                         break;
 399
 400         /* end of "while line is read from /etc/mdev.conf" */
 401         } while (ENABLE_FEATURE_MDEV_CONF);
 402
 403         if (ENABLE_FEATURE_MDEV_CONF)
 404                 config_close(parser);
 405         free(subsystem_slash_devname);
 406 }
 407
 408 /* File callback for /sys/ traversal */
 409 static int FAST_FUNC fileAction(const char *fileName,
 410                 struct stat *statbuf UNUSED_PARAM,
 411                 void *userData,
 412                 int depth UNUSED_PARAM)
 413 {
 414         size_t len = strlen(fileName) - 4; /* can't underflow */
 415         char *scratch = userData;
 416
 417         /* len check is for paranoid reasons */
 418         if (strcmp(fileName + len, "/dev") != 0 || len >= PATH_MAX)
 419                 return FALSE;
 420
 421         strcpy(scratch, fileName);
 422         scratch[len] = '\0';
 423         make_device(scratch, /*delete:*/ 0);
 424
 425         return TRUE;
 426 }
 427
 428 /* Directory callback for /sys/ traversal */
 429 static int FAST_FUNC dirAction(const char *fileName UNUSED_PARAM,
 430                 struct stat *statbuf UNUSED_PARAM,
 431                 void *userData UNUSED_PARAM,
 432                 int depth)
 433 {
 434         /* Extract device subsystem -- the name of the directory
 435          * under /sys/class/ */
 436         if (1 == depth) {
 437                 free(G.subsystem);
 438                 G.subsystem = strrchr(fileName, '/');
 439                 if (G.subsystem)
 440                         G.subsystem = xstrdup(G.subsystem + 1);
 441         }
 442
 443         return (depth >= MAX_SYSFS_DEPTH ? SKIP : TRUE);
 444 }
 445
 446 /* For the full gory details, see linux/Documentation/firmware_class/README
 447  *
 448  * Firmware loading works like this:
 449  * - kernel sets FIRMWARE env var
 450  * - userspace checks /lib/firmware/$FIRMWARE
 451  * - userspace waits for /sys/$DEVPATH/loading to appear
 452  * - userspace writes "1" to /sys/$DEVPATH/loading
 453  * - userspace copies /lib/firmware/$FIRMWARE into /sys/$DEVPATH/data
 454  * - userspace writes "0" (worked) or "-1" (failed) to /sys/$DEVPATH/loading
 455  * - kernel loads firmware into device
 456  */
 457 static void load_firmware(const char *firmware, const char *sysfs_path)
 458 {
 459         int cnt;
 460         int firmware_fd, loading_fd, data_fd;
 461
 462         /* check for /lib/firmware/$FIRMWARE */
 463         xchdir("/lib/firmware");
 464         firmware_fd = xopen(firmware, O_RDONLY);
 465
 466         /* in case we goto out ... */
 467         data_fd = -1;
 468
 469         /* check for /sys/$DEVPATH/loading ... give 30 seconds to appear */
 470         xchdir(sysfs_path);
 471         for (cnt = 0; cnt < 30; ++cnt) {
 472                 loading_fd = open("loading", O_WRONLY);
 473                 if (loading_fd != -1)
 474                         goto loading;
 475                 sleep(1);
 476         }
 477         goto out;
 478
 479  loading:
 480         /* tell kernel we're loading by "echo 1 > /sys/$DEVPATH/loading" */
 481         if (full_write(loading_fd, "1", 1) != 1)
 482                 goto out;
 483
 484         /* load firmware into /sys/$DEVPATH/data */
 485         data_fd = open("data", O_WRONLY);
 486         if (data_fd == -1)
 487                 goto out;
 488         cnt = bb_copyfd_eof(firmware_fd, data_fd);
 489
 490         /* tell kernel result by "echo [0|-1] > /sys/$DEVPATH/loading" */
 491         if (cnt > 0)
 492                 full_write(loading_fd, "0", 1);
 493         else
 494                 full_write(loading_fd, "-1", 2);
 495
 496  out:
 497         if (ENABLE_FEATURE_CLEAN_UP) {
 498                 close(firmware_fd);
 499                 close(loading_fd);
 500                 close(data_fd);
 501         }
 502 }
 503
 504 int mdev_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 505 int mdev_main(int argc UNUSED_PARAM, char **argv)
 506 {
 507         RESERVE_CONFIG_BUFFER(temp, PATH_MAX + SCRATCH_SIZE);
 508
 509         /* We can be called as hotplug helper */
 510         /* Kernel cannot provide suitable stdio fds for us, do it ourself */
 511         bb_sanitize_stdio();
 512
 513         /* Force the configuration file settings exactly */
 514         umask(0);
 515
 516         xchdir("/dev");
 517
 518         if (argv[1] && strcmp(argv[1], "-s") == 0) {
 519                 /* Scan:
 520                  * mdev -s
 521                  */
 522                 struct stat st;
 523
 524                 xstat("/", &st);
 525                 G.root_major = major(st.st_dev);
 526                 G.root_minor = minor(st.st_dev);
 527
 528                 /* ACTION_FOLLOWLINKS is needed since in newer kernels
 529                  * /sys/block/loop* (for example) are symlinks to dirs,
 530                  * not real directories.
 531                  * (kernel's CONFIG_SYSFS_DEPRECATED makes them real dirs,
 532                  * but we can't enforce that on users)
 533                  */
 534                 if (access("/sys/class/block", F_OK) != 0) {
 535                         /* Scan obsolete /sys/block only if /sys/class/block
 536                          * doesn't exist. Otherwise we'll have dupes.
 537                          * Also, do not complain if it doesn't exist.
 538                          * Some people configure kernel to have no blockdevs.
 539                          */
 540                         recursive_action("/sys/block",
 541                                 ACTION_RECURSE | ACTION_FOLLOWLINKS | ACTION_QUIET,
 542                                 fileAction, dirAction, temp, 0);
 543                 }
 544                 recursive_action("/sys/class",
 545                         ACTION_RECURSE | ACTION_FOLLOWLINKS,
 546                         fileAction, dirAction, temp, 0);
 547         } else {
 548                 char *fw;
 549                 char *seq;
 550                 char *action;
 551                 char *env_path;
 552                 static const char keywords[] ALIGN1 = "remove\0add\0";
 553                 enum { OP_remove = 0, OP_add };
 554                 smalluint op;
 555
 556                 /* Hotplug:
 557                  * env ACTION=... DEVPATH=... SUBSYSTEM=... [SEQNUM=...] mdev
 558                  * ACTION can be "add" or "remove"
 559                  * DEVPATH is like "/block/sda" or "/class/input/mice"
 560                  */
 561                 action = getenv("ACTION");
 562                 env_path = getenv("DEVPATH");
 563                 G.subsystem = getenv("SUBSYSTEM");
 564                 if (!action || !env_path /*|| !G.subsystem*/)
 565                         bb_show_usage();
 566                 fw = getenv("FIRMWARE");
 567                 op = index_in_strings(keywords, action);
 568                 /* If it exists, does /dev/mdev.seq match $SEQNUM?
 569                  * If it does not match, earlier mdev is running
 570                  * in parallel, and we need to wait */
 571                 seq = getenv("SEQNUM");
 572                 if (seq) {
 573                         int timeout = 2000 / 32; /* 2000 msec */
 574                         do {
 575                                 int seqlen;
 576                                 char seqbuf[sizeof(int)*3 + 2];
 577
 578                                 seqlen = open_read_close("mdev.seq", seqbuf, sizeof(seqbuf-1));
 579                                 if (seqlen < 0) {
 580                                         seq = NULL;
 581                                         break;
 582                                 }
 583                                 seqbuf[seqlen] = '\0';
 584                                 if (seqbuf[0] == '\n' /* seed file? */
 585                                  || strcmp(seq, seqbuf) == 0 /* correct idx? */
 586                                 ) {
 587                                         break;
 588                                 }
 589                                 usleep(32*1000);
 590                         } while (--timeout);
 591                 }
 592
 593                 snprintf(temp, PATH_MAX, "/sys%s", env_path);
 594                 if (op == OP_remove) {
 595                         /* Ignoring "remove firmware". It was reported
 596                          * to happen and to cause erroneous deletion
 597                          * of device nodes. */
 598                         if (!fw)
 599                                 make_device(temp, /*delete:*/ 1);
 600                 }
 601                 else if (op == OP_add) {
 602                         make_device(temp, /*delete:*/ 0);
 603                         if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE) {
 604                                 if (fw)
 605                                         load_firmware(fw, temp);
 606                         }
 607                 }
 608
 609                 if (seq) {
 610                         xopen_xwrite_close("mdev.seq", utoa(xatou(seq) + 1));
 611                 }
 612         }
 613
 614         if (ENABLE_FEATURE_CLEAN_UP)
 615                 RELEASE_CONFIG_BUFFER(temp);
 616
 617         return EXIT_SUCCESS;
 618 }