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