src/udev/udev-builtin-path_id.c

   1 /*
   2  * compose persistent device path
   3  *
   4  * Copyright (C) 2009-2011 Kay Sievers <kay@vrfy.org>
   5  *
   6  * Logic based on Hannes Reinecke's shell script.
   7  *
   8  * This program is free software: you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation, either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20  */
  21
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <stdarg.h>
  25 #include <unistd.h>
  26 #include <string.h>
  27 #include <ctype.h>
  28 #include <fcntl.h>
  29 #include <errno.h>
  30 #include <dirent.h>
  31 #include <getopt.h>
  32
  33 #include "udev.h"
  34
  35 _printf_(2,3)
  36 static int path_prepend(char **path, const char *fmt, ...) {
  37         va_list va;
  38         char *pre;
  39         int err = 0;
  40
  41         va_start(va, fmt);
  42         err = vasprintf(&pre, fmt, va);
  43         va_end(va);
  44         if (err < 0)
  45                 goto out;
  46
  47         if (*path != NULL) {
  48                 char *new;
  49
  50                 err = asprintf(&new, "%s-%s", pre, *path);
  51                 free(pre);
  52                 if (err < 0)
  53                         goto out;
  54                 free(*path);
  55                 *path = new;
  56         } else {
  57                 *path = pre;
  58         }
  59 out:
  60         return err;
  61 }
  62
  63 /*
  64 ** Linux only supports 32 bit luns.
  65 ** See drivers/scsi/scsi_scan.c::scsilun_to_int() for more details.
  66 */
  67 static int format_lun_number(struct udev_device *dev, char **path) {
  68         unsigned long lun = strtoul(udev_device_get_sysnum(dev), NULL, 10);
  69
  70         /* address method 0, peripheral device addressing with bus id of zero */
  71         if (lun < 256)
  72                 return path_prepend(path, "lun-%lu", lun);
  73         /* handle all other lun addressing methods by using a variant of the original lun format */
  74         return path_prepend(path, "lun-0x%04lx%04lx00000000", lun & 0xffff, (lun >> 16) & 0xffff);
  75 }
  76
  77 static struct udev_device *skip_subsystem(struct udev_device *dev, const char *subsys) {
  78         struct udev_device *parent = dev;
  79
  80         assert(dev);
  81         assert(subsys);
  82
  83         while (parent != NULL) {
  84                 const char *subsystem;
  85
  86                 subsystem = udev_device_get_subsystem(parent);
  87                 if (subsystem == NULL || !streq(subsystem, subsys))
  88                         break;
  89                 dev = parent;
  90                 parent = udev_device_get_parent(parent);
  91         }
  92         return dev;
  93 }
  94
  95 static struct udev_device *handle_scsi_fibre_channel(struct udev_device *parent, char **path) {
  96         struct udev *udev  = udev_device_get_udev(parent);
  97         struct udev_device *targetdev;
  98         struct udev_device *fcdev = NULL;
  99         const char *port;
 100         char *lun = NULL;
 101
 102         assert(parent);
 103         assert(path);
 104
 105         targetdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_target");
 106         if (targetdev == NULL)
 107                 return NULL;
 108
 109         fcdev = udev_device_new_from_subsystem_sysname(udev, "fc_transport", udev_device_get_sysname(targetdev));
 110         if (fcdev == NULL)
 111                 return NULL;
 112         port = udev_device_get_sysattr_value(fcdev, "port_name");
 113         if (port == NULL) {
 114                 parent = NULL;
 115                 goto out;
 116         }
 117
 118         format_lun_number(parent, &lun);
 119         path_prepend(path, "fc-%s-%s", port, lun);
 120         if (lun)
 121                 free(lun);
 122 out:
 123         udev_device_unref(fcdev);
 124         return parent;
 125 }
 126
 127 static struct udev_device *handle_scsi_sas_wide_port(struct udev_device *parent, char **path) {
 128         struct udev *udev  = udev_device_get_udev(parent);
 129         struct udev_device *targetdev;
 130         struct udev_device *target_parent;
 131         struct udev_device *sasdev;
 132         const char *sas_address;
 133         char *lun = NULL;
 134
 135         assert(parent);
 136         assert(path);
 137
 138         targetdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_target");
 139         if (targetdev == NULL)
 140                 return NULL;
 141
 142         target_parent = udev_device_get_parent(targetdev);
 143         if (target_parent == NULL)
 144                 return NULL;
 145
 146         sasdev = udev_device_new_from_subsystem_sysname(udev, "sas_device",
 147                                 udev_device_get_sysname(target_parent));
 148         if (sasdev == NULL)
 149                 return NULL;
 150
 151         sas_address = udev_device_get_sysattr_value(sasdev, "sas_address");
 152         if (sas_address == NULL) {
 153                 parent = NULL;
 154                 goto out;
 155         }
 156
 157         format_lun_number(parent, &lun);
 158         path_prepend(path, "sas-%s-%s", sas_address, lun);
 159         if (lun)
 160                 free(lun);
 161 out:
 162         udev_device_unref(sasdev);
 163         return parent;
 164 }
 165
 166 static struct udev_device *handle_scsi_sas(struct udev_device *parent, char **path)
 167 {
 168         struct udev *udev  = udev_device_get_udev(parent);
 169         struct udev_device *targetdev;
 170         struct udev_device *target_parent;
 171         struct udev_device *port;
 172         struct udev_device *expander;
 173         struct udev_device *target_sasdev = NULL;
 174         struct udev_device *expander_sasdev = NULL;
 175         struct udev_device *port_sasdev = NULL;
 176         const char *sas_address = NULL;
 177         const char *phy_id;
 178         const char *phy_count;
 179         char *lun = NULL;
 180
 181         assert(parent);
 182         assert(path);
 183
 184         targetdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_target");
 185         if (targetdev == NULL)
 186                 return NULL;
 187
 188         target_parent = udev_device_get_parent(targetdev);
 189         if (target_parent == NULL)
 190                 return NULL;
 191
 192         /* Get sas device */
 193         target_sasdev = udev_device_new_from_subsystem_sysname(udev,
 194                           "sas_device", udev_device_get_sysname(target_parent));
 195         if (target_sasdev == NULL)
 196                 return NULL;
 197
 198         /* The next parent is sas port */
 199         port = udev_device_get_parent(target_parent);
 200         if (port == NULL) {
 201                 parent = NULL;
 202                 goto out;
 203         }
 204
 205         /* Get port device */
 206         port_sasdev = udev_device_new_from_subsystem_sysname(udev,
 207                           "sas_port", udev_device_get_sysname(port));
 208
 209         phy_count = udev_device_get_sysattr_value(port_sasdev, "num_phys");
 210         if (phy_count == NULL) {
 211                parent = NULL;
 212                goto out;
 213         }
 214
 215         /* Check if we are simple disk */
 216         if (strncmp(phy_count, "1", 2) != 0) {
 217                  parent = handle_scsi_sas_wide_port(parent, path);
 218                  goto out;
 219         }
 220
 221         /* Get connected phy */
 222         phy_id = udev_device_get_sysattr_value(target_sasdev, "phy_identifier");
 223         if (phy_id == NULL) {
 224                 parent = NULL;
 225                 goto out;
 226         }
 227
 228         /* The port's parent is either hba or expander */
 229         expander = udev_device_get_parent(port);
 230         if (expander == NULL) {
 231                 parent = NULL;
 232                 goto out;
 233         }
 234
 235         /* Get expander device */
 236         expander_sasdev = udev_device_new_from_subsystem_sysname(udev,
 237                           "sas_device", udev_device_get_sysname(expander));
 238         if (expander_sasdev != NULL) {
 239                  /* Get expander's address */
 240                  sas_address = udev_device_get_sysattr_value(expander_sasdev,
 241                                                     "sas_address");
 242                  if (sas_address == NULL) {
 243                         parent = NULL;
 244                         goto out;
 245                  }
 246         }
 247
 248         format_lun_number(parent, &lun);
 249         if (sas_address)
 250                  path_prepend(path, "sas-exp%s-phy%s-%s", sas_address, phy_id, lun);
 251         else
 252                  path_prepend(path, "sas-phy%s-%s", phy_id, lun);
 253
 254         if (lun)
 255                 free(lun);
 256 out:
 257         udev_device_unref(target_sasdev);
 258         udev_device_unref(expander_sasdev);
 259         udev_device_unref(port_sasdev);
 260         return parent;
 261 }
 262
 263 static struct udev_device *handle_scsi_iscsi(struct udev_device *parent, char **path) {
 264         struct udev *udev  = udev_device_get_udev(parent);
 265         struct udev_device *transportdev;
 266         struct udev_device *sessiondev = NULL;
 267         const char *target;
 268         char *connname;
 269         struct udev_device *conndev = NULL;
 270         const char *addr;
 271         const char *port;
 272         char *lun = NULL;
 273
 274         assert(parent);
 275         assert(path);
 276
 277         /* find iscsi session */
 278         transportdev = parent;
 279         for (;;) {
 280                 transportdev = udev_device_get_parent(transportdev);
 281                 if (transportdev == NULL)
 282                         return NULL;
 283                 if (startswith(udev_device_get_sysname(transportdev), "session"))
 284                         break;
 285         }
 286
 287         /* find iscsi session device */
 288         sessiondev = udev_device_new_from_subsystem_sysname(udev, "iscsi_session", udev_device_get_sysname(transportdev));
 289         if (sessiondev == NULL)
 290                 return NULL;
 291         target = udev_device_get_sysattr_value(sessiondev, "targetname");
 292         if (target == NULL) {
 293                 parent = NULL;
 294                 goto out;
 295         }
 296
 297         if (asprintf(&connname, "connection%s:0", udev_device_get_sysnum(transportdev)) < 0) {
 298                 parent = NULL;
 299                 goto out;
 300         }
 301         conndev = udev_device_new_from_subsystem_sysname(udev, "iscsi_connection", connname);
 302         free(connname);
 303         if (conndev == NULL) {
 304                 parent = NULL;
 305                 goto out;
 306         }
 307         addr = udev_device_get_sysattr_value(conndev, "persistent_address");
 308         port = udev_device_get_sysattr_value(conndev, "persistent_port");
 309         if (addr == NULL || port == NULL) {
 310                 parent = NULL;
 311                 goto out;
 312         }
 313
 314         format_lun_number(parent, &lun);
 315         path_prepend(path, "ip-%s:%s-iscsi-%s-%s", addr, port, target, lun);
 316         if (lun)
 317                 free(lun);
 318 out:
 319         udev_device_unref(sessiondev);
 320         udev_device_unref(conndev);
 321         return parent;
 322 }
 323
 324 static struct udev_device *handle_scsi_default(struct udev_device *parent, char **path) {
 325         struct udev_device *hostdev;
 326         int host, bus, target, lun;
 327         const char *name;
 328         char *base;
 329         char *pos;
 330         DIR *dir;
 331         struct dirent *dent;
 332         int basenum;
 333
 334         assert(parent);
 335         assert(path);
 336
 337         hostdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_host");
 338         if (hostdev == NULL)
 339                 return NULL;
 340
 341         name = udev_device_get_sysname(parent);
 342         if (sscanf(name, "%d:%d:%d:%d", &host, &bus, &target, &lun) != 4)
 343                 return NULL;
 344
 345         /*
 346          * Rebase host offset to get the local relative number
 347          *
 348          * Note: This is by definition racy, unreliable and too simple.
 349          * Please do not copy this model anywhere. It's just a left-over
 350          * from the time we had no idea how things should look like in
 351          * the end.
 352          *
 353          * Making assumptions about a global in-kernel counter and use
 354          * that to calculate a local offset is a very broken concept. It
 355          * can only work as long as things are in strict order.
 356          *
 357          * The kernel needs to export the instance/port number of a
 358          * controller directly, without the need for rebase magic like
 359          * this. Manual driver unbind/bind, parallel hotplug/unplug will
 360          * get into the way of this "I hope it works" logic.
 361          */
 362         basenum = -1;
 363         base = strdup(udev_device_get_syspath(hostdev));
 364         if (base == NULL)
 365                 return NULL;
 366         pos = strrchr(base, '/');
 367         if (pos == NULL) {
 368                 parent = NULL;
 369                 goto out;
 370         }
 371         pos[0] = '\0';
 372         dir = opendir(base);
 373         if (dir == NULL) {
 374                 parent = NULL;
 375                 goto out;
 376         }
 377         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 378                 char *rest;
 379                 int i;
 380
 381                 if (dent->d_name[0] == '.')
 382                         continue;
 383                 if (dent->d_type != DT_DIR && dent->d_type != DT_LNK)
 384                         continue;
 385                 if (!startswith(dent->d_name, "host"))
 386                         continue;
 387                 i = strtoul(&dent->d_name[4], &rest, 10);
 388                 if (rest[0] != '\0')
 389                         continue;
 390                 /*
 391                  * find the smallest number; the host really needs to export its
 392                  * own instance number per parent device; relying on the global host
 393                  * enumeration and plainly rebasing the numbers sounds unreliable
 394                  */
 395                 if (basenum == -1 || i < basenum)
 396                         basenum = i;
 397         }
 398         closedir(dir);
 399         if (basenum == -1) {
 400                 parent = NULL;
 401                 goto out;
 402         }
 403         host -= basenum;
 404
 405         path_prepend(path, "scsi-%u:%u:%u:%u", host, bus, target, lun);
 406 out:
 407         free(base);
 408         return hostdev;
 409 }
 410
 411 static struct udev_device *handle_scsi_hyperv(struct udev_device *parent, char **path) {
 412         struct udev_device *hostdev;
 413         struct udev_device *vmbusdev;
 414         const char *guid_str;
 415         char *lun = NULL;
 416         char guid[38];
 417         size_t i, k;
 418
 419         assert(parent);
 420         assert(path);
 421
 422         hostdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_host");
 423         if (!hostdev)
 424                 return NULL;
 425
 426         vmbusdev = udev_device_get_parent(hostdev);
 427         if (!vmbusdev)
 428                 return NULL;
 429
 430         guid_str = udev_device_get_sysattr_value(vmbusdev, "device_id");
 431         if (!guid_str)
 432                 return NULL;
 433
 434         if (strlen(guid_str) < 37 || guid_str[0] != '{' || guid_str[36] != '}')
 435                 return NULL;
 436
 437         for (i = 1, k = 0; i < 36; i++) {
 438                 if (guid_str[i] == '-')
 439                         continue;
 440                 guid[k++] = guid_str[i];
 441         }
 442         guid[k] = '\0';
 443
 444         format_lun_number(parent, &lun);
 445         path_prepend(path, "vmbus-%s-%s", guid, lun);
 446         free(lun);
 447         return parent;
 448 }
 449
 450 static struct udev_device *handle_scsi(struct udev_device *parent, char **path, bool *supported_parent) {
 451         const char *devtype;
 452         const char *name;
 453         const char *id;
 454
 455         devtype = udev_device_get_devtype(parent);
 456         if (devtype == NULL || !streq(devtype, "scsi_device"))
 457                 return parent;
 458
 459         /* firewire */
 460         id = udev_device_get_sysattr_value(parent, "ieee1394_id");
 461         if (id != NULL) {
 462                 parent = skip_subsystem(parent, "scsi");
 463                 path_prepend(path, "ieee1394-0x%s", id);
 464                 *supported_parent = true;
 465                 goto out;
 466         }
 467
 468         /* scsi sysfs does not have a "subsystem" for the transport */
 469         name = udev_device_get_syspath(parent);
 470
 471         if (strstr(name, "/rport-") != NULL) {
 472                 parent = handle_scsi_fibre_channel(parent, path);
 473                 *supported_parent = true;
 474                 goto out;
 475         }
 476
 477         if (strstr(name, "/end_device-") != NULL) {
 478                 parent = handle_scsi_sas(parent, path);
 479                 *supported_parent = true;
 480                 goto out;
 481         }
 482
 483         if (strstr(name, "/session") != NULL) {
 484                 parent = handle_scsi_iscsi(parent, path);
 485                 *supported_parent = true;
 486                 goto out;
 487         }
 488
 489         /*
 490          * We do not support the ATA transport class, it uses global counters
 491          * to name the ata devices which numbers spread across multiple
 492          * controllers.
 493          *
 494          * The real link numbers are not exported. Also, possible chains of ports
 495          * behind port multipliers cannot be composed that way.
 496          *
 497          * Until all that is solved at the kernel level, there are no by-path/
 498          * links for ATA devices.
 499          */
 500         if (strstr(name, "/ata") != NULL) {
 501                 parent = NULL;
 502                 goto out;
 503         }
 504
 505         if (strstr(name, "/vmbus_") != NULL) {
 506                 parent = handle_scsi_hyperv(parent, path);
 507                 goto out;
 508         }
 509
 510         parent = handle_scsi_default(parent, path);
 511 out:
 512         return parent;
 513 }
 514
 515 static struct udev_device *handle_cciss(struct udev_device *parent, char **path) {
 516         const char *str;
 517         unsigned int controller, disk;
 518
 519         str = udev_device_get_sysname(parent);
 520         if (sscanf(str, "c%ud%u%*s", &controller, &disk) != 2)
 521                 return NULL;
 522
 523         path_prepend(path, "cciss-disk%u", disk);
 524         parent = skip_subsystem(parent, "cciss");
 525         return parent;
 526 }
 527
 528 static void handle_scsi_tape(struct udev_device *dev, char **path) {
 529         const char *name;
 530
 531         /* must be the last device in the syspath */
 532         if (*path != NULL)
 533                 return;
 534
 535         name = udev_device_get_sysname(dev);
 536         if (startswith(name, "nst") && strchr("lma", name[3]) != NULL)
 537                 path_prepend(path, "nst%c", name[3]);
 538         else if (startswith(name, "st") && strchr("lma", name[2]) != NULL)
 539                 path_prepend(path, "st%c", name[2]);
 540 }
 541
 542 static struct udev_device *handle_usb(struct udev_device *parent, char **path) {
 543         const char *devtype;
 544         const char *str;
 545         const char *port;
 546
 547         devtype = udev_device_get_devtype(parent);
 548         if (devtype == NULL)
 549                 return parent;
 550         if (!streq(devtype, "usb_interface") && !streq(devtype, "usb_device"))
 551                 return parent;
 552
 553         str = udev_device_get_sysname(parent);
 554         port = strchr(str, '-');
 555         if (port == NULL)
 556                 return parent;
 557         port++;
 558
 559         parent = skip_subsystem(parent, "usb");
 560         path_prepend(path, "usb-0:%s", port);
 561         return parent;
 562 }
 563
 564 static struct udev_device *handle_bcma(struct udev_device *parent, char **path) {
 565         const char *sysname;
 566         unsigned int core;
 567
 568         sysname = udev_device_get_sysname(parent);
 569         if (sscanf(sysname, "bcma%*u:%u", &core) != 1)
 570                 return NULL;
 571
 572         path_prepend(path, "bcma-%u", core);
 573         return parent;
 574 }
 575
 576 static struct udev_device *handle_ccw(struct udev_device *parent, struct udev_device *dev, char **path) {
 577         struct udev_device *scsi_dev;
 578
 579         assert(parent);
 580         assert(dev);
 581         assert(path);
 582
 583         scsi_dev = udev_device_get_parent_with_subsystem_devtype(dev, "scsi", "scsi_device");
 584         if (scsi_dev != NULL) {
 585                 const char *wwpn;
 586                 const char *lun;
 587                 const char *hba_id;
 588
 589                 hba_id = udev_device_get_sysattr_value(scsi_dev, "hba_id");
 590                 wwpn = udev_device_get_sysattr_value(scsi_dev, "wwpn");
 591                 lun = udev_device_get_sysattr_value(scsi_dev, "fcp_lun");
 592                 if (hba_id != NULL && lun != NULL && wwpn != NULL) {
 593                         path_prepend(path, "ccw-%s-zfcp-%s:%s", hba_id, wwpn, lun);
 594                         goto out;
 595                 }
 596         }
 597
 598         path_prepend(path, "ccw-%s", udev_device_get_sysname(parent));
 599 out:
 600         parent = skip_subsystem(parent, "ccw");
 601         return parent;
 602 }
 603
 604 static int builtin_path_id(struct udev_device *dev, int argc, char *argv[], bool test) {
 605         struct udev_device *parent;
 606         char *path = NULL;
 607         bool supported_transport = false;
 608         bool supported_parent = false;
 609
 610         assert(dev);
 611
 612         /* S390 ccw bus */
 613         parent = udev_device_get_parent_with_subsystem_devtype(dev, "ccw", NULL);
 614         if (parent != NULL) {
 615                 handle_ccw(parent, dev, &path);
 616                 goto out;
 617         }
 618
 619         /* walk up the chain of devices and compose path */
 620         parent = dev;
 621         while (parent != NULL) {
 622                 const char *subsys;
 623
 624                 subsys = udev_device_get_subsystem(parent);
 625                 if (subsys == NULL) {
 626                         ;
 627                 } else if (streq(subsys, "scsi_tape")) {
 628                         handle_scsi_tape(parent, &path);
 629                 } else if (streq(subsys, "scsi")) {
 630                         parent = handle_scsi(parent, &path, &supported_parent);
 631                         supported_transport = true;
 632                 } else if (streq(subsys, "cciss")) {
 633                         parent = handle_cciss(parent, &path);
 634                         supported_transport = true;
 635                 } else if (streq(subsys, "usb")) {
 636                         parent = handle_usb(parent, &path);
 637                         supported_transport = true;
 638                 } else if (streq(subsys, "bcma")) {
 639                         parent = handle_bcma(parent, &path);
 640                         supported_transport = true;
 641                 } else if (streq(subsys, "serio")) {
 642                         path_prepend(&path, "serio-%s", udev_device_get_sysnum(parent));
 643                         parent = skip_subsystem(parent, "serio");
 644                 } else if (streq(subsys, "pci")) {
 645                         path_prepend(&path, "pci-%s", udev_device_get_sysname(parent));
 646                         parent = skip_subsystem(parent, "pci");
 647                         supported_parent = true;
 648                 } else if (streq(subsys, "platform")) {
 649                         path_prepend(&path, "platform-%s", udev_device_get_sysname(parent));
 650                         parent = skip_subsystem(parent, "platform");
 651                         supported_transport = true;
 652                         supported_parent = true;
 653                 } else if (streq(subsys, "acpi")) {
 654                         path_prepend(&path, "acpi-%s", udev_device_get_sysname(parent));
 655                         parent = skip_subsystem(parent, "acpi");
 656                         supported_parent = true;
 657                 } else if (streq(subsys, "xen")) {
 658                         path_prepend(&path, "xen-%s", udev_device_get_sysname(parent));
 659                         parent = skip_subsystem(parent, "xen");
 660                         supported_parent = true;
 661                 } else if (streq(subsys, "scm")) {
 662                         path_prepend(&path, "scm-%s", udev_device_get_sysname(parent));
 663                         parent = skip_subsystem(parent, "scm");
 664                         supported_transport = true;
 665                         supported_parent = true;
 666                 }
 667
 668                 if (parent)
 669                         parent = udev_device_get_parent(parent);
 670         }
 671
 672         /*
 673          * Do not return devices with an unknown parent device type. They
 674          * might produce conflicting IDs if the parent does not provide a
 675          * unique and predictable name.
 676          */
 677         if (!supported_parent) {
 678                 free(path);
 679                 path = NULL;
 680         }
 681
 682         /*
 683          * Do not return block devices without a well-known transport. Some
 684          * devices do not expose their buses and do not provide a unique
 685          * and predictable name that way.
 686          */
 687         if (streq(udev_device_get_subsystem(dev), "block") && !supported_transport) {
 688                 free(path);
 689                 path = NULL;
 690         }
 691
 692 out:
 693         if (path != NULL) {
 694                 char tag[UTIL_NAME_SIZE];
 695                 size_t i;
 696                 const char *p;
 697
 698                 /* compose valid udev tag name */
 699                 for (p = path, i = 0; *p; p++) {
 700                         if ((*p >= '0' && *p <= '9') ||
 701                             (*p >= 'A' && *p <= 'Z') ||
 702                             (*p >= 'a' && *p <= 'z') ||
 703                             *p == '-') {
 704                                 tag[i++] = *p;
 705                                 continue;
 706                         }
 707
 708                         /* skip all leading '_' */
 709                         if (i == 0)
 710                                 continue;
 711
 712                         /* avoid second '_' */
 713                         if (tag[i-1] == '_')
 714                                 continue;
 715
 716                         tag[i++] = '_';
 717                 }
 718                 /* strip trailing '_' */
 719                 while (i > 0 && tag[i-1] == '_')
 720                         i--;
 721                 tag[i] = '\0';
 722
 723                 udev_builtin_add_property(dev, test, "ID_PATH", path);
 724                 udev_builtin_add_property(dev, test, "ID_PATH_TAG", tag);
 725                 free(path);
 726                 return EXIT_SUCCESS;
 727         }
 728         return EXIT_FAILURE;
 729 }
 730
 731 const struct udev_builtin udev_builtin_path_id = {
 732         .name = "path_id",
 733         .cmd = builtin_path_id,
 734         .help = "Compose persistent device path",
 735         .run_once = true,
 736 };