src/libsystemd/sd-device/sd-device.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <ctype.h>
   4 #include <net/if.h>
   5 #include <sys/types.h>
   6
   7 #include "sd-device.h"
   8
   9 #include "alloc-util.h"
  10 #include "device-internal.h"
  11 #include "device-private.h"
  12 #include "device-util.h"
  13 #include "dirent-util.h"
  14 #include "fd-util.h"
  15 #include "fileio.h"
  16 #include "fs-util.h"
  17 #include "hashmap.h"
  18 #include "macro.h"
  19 #include "parse-util.h"
  20 #include "path-util.h"
  21 #include "set.h"
  22 #include "socket-util.h"
  23 #include "stat-util.h"
  24 #include "string-util.h"
  25 #include "strv.h"
  26 #include "strxcpyx.h"
  27 #include "util.h"
  28
  29 int device_new_aux(sd_device **ret) {
  30         sd_device *device = NULL;
  31
  32         assert(ret);
  33
  34         device = new(sd_device, 1);
  35         if (!device)
  36                 return -ENOMEM;
  37
  38         *device = (sd_device) {
  39                 .n_ref = 1,
  40                 .watch_handle = -1,
  41         };
  42
  43         *ret = device;
  44         return 0;
  45 }
  46
  47 static sd_device *device_free(sd_device *device) {
  48         assert(device);
  49
  50         sd_device_unref(device->parent);
  51         free(device->syspath);
  52         free(device->sysname);
  53         free(device->devtype);
  54         free(device->devname);
  55         free(device->subsystem);
  56         free(device->driver_subsystem);
  57         free(device->driver);
  58         free(device->id_filename);
  59         free(device->properties_strv);
  60         free(device->properties_nulstr);
  61
  62         ordered_hashmap_free_free_free(device->properties);
  63         ordered_hashmap_free_free_free(device->properties_db);
  64         hashmap_free_free_free(device->sysattr_values);
  65         set_free_free(device->sysattrs);
  66         set_free_free(device->tags);
  67         set_free_free(device->devlinks);
  68
  69         return mfree(device);
  70 }
  71
  72 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_device, sd_device, device_free);
  73
  74 int device_add_property_aux(sd_device *device, const char *_key, const char *_value, bool db) {
  75         OrderedHashmap **properties;
  76
  77         assert(device);
  78         assert(_key);
  79
  80         if (db)
  81                 properties = &device->properties_db;
  82         else
  83                 properties = &device->properties;
  84
  85         if (_value) {
  86                 _cleanup_free_ char *key = NULL, *value = NULL, *old_key = NULL, *old_value = NULL;
  87                 int r;
  88
  89                 r = ordered_hashmap_ensure_allocated(properties, &string_hash_ops);
  90                 if (r < 0)
  91                         return r;
  92
  93                 key = strdup(_key);
  94                 if (!key)
  95                         return -ENOMEM;
  96
  97                 value = strdup(_value);
  98                 if (!value)
  99                         return -ENOMEM;
 100
 101                 old_value = ordered_hashmap_get2(*properties, key, (void**) &old_key);
 102
 103                 r = ordered_hashmap_replace(*properties, key, value);
 104                 if (r < 0)
 105                         return r;
 106
 107                 key = NULL;
 108                 value = NULL;
 109         } else {
 110                 _cleanup_free_ char *key = NULL;
 111                 _cleanup_free_ char *value = NULL;
 112
 113                 value = ordered_hashmap_remove2(*properties, _key, (void**) &key);
 114         }
 115
 116         if (!db) {
 117                 device->properties_generation++;
 118                 device->properties_buf_outdated = true;
 119         }
 120
 121         return 0;
 122 }
 123
 124 int device_add_property_internal(sd_device *device, const char *key, const char *value) {
 125         return device_add_property_aux(device, key, value, false);
 126 }
 127
 128 int device_set_syspath(sd_device *device, const char *_syspath, bool verify) {
 129         _cleanup_free_ char *syspath = NULL;
 130         const char *devpath;
 131         int r;
 132
 133         assert(device);
 134         assert(_syspath);
 135
 136         /* must be a subdirectory of /sys */
 137         if (!path_startswith(_syspath, "/sys/")) {
 138                 log_debug("sd-device: syspath '%s' is not a subdirectory of /sys", _syspath);
 139                 return -EINVAL;
 140         }
 141
 142         if (verify) {
 143                 r = chase_symlinks(_syspath, NULL, 0, &syspath);
 144                 if (r == -ENOENT)
 145                         return -ENODEV; /* the device does not exist (any more?) */
 146                 if (r < 0)
 147                         return log_debug_errno(r, "sd-device: could not get target of '%s': %m", _syspath);
 148
 149                 if (!path_startswith(syspath, "/sys")) {
 150                         _cleanup_free_ char *real_sys = NULL, *new_syspath = NULL;
 151                         char *p;
 152
 153                         /* /sys is a symlink to somewhere sysfs is mounted on? In that case, we convert the path to real sysfs to "/sys". */
 154                         r = chase_symlinks("/sys", NULL, 0, &real_sys);
 155                         if (r < 0)
 156                                 return log_debug_errno(r, "sd-device: could not chase symlink /sys: %m");
 157
 158                         p = path_startswith(syspath, real_sys);
 159                         if (!p) {
 160                                 log_debug("sd-device: canonicalized path '%s' does not starts with sysfs mount point '%s'", syspath, real_sys);
 161                                 return -ENODEV;
 162                         }
 163
 164                         new_syspath = strjoin("/sys/", p);
 165                         if (!new_syspath)
 166                                 return log_oom();
 167
 168                         free_and_replace(syspath, new_syspath);
 169                         path_simplify(syspath, false);
 170                 }
 171
 172                 if (path_startswith(syspath,  "/sys/devices/")) {
 173                         char *path;
 174
 175                         /* all 'devices' require an 'uevent' file */
 176                         path = strjoina(syspath, "/uevent");
 177                         r = access(path, F_OK);
 178                         if (r < 0) {
 179                                 if (errno == ENOENT)
 180                                         /* this is not a valid device */
 181                                         return -ENODEV;
 182
 183                                 return log_debug_errno(errno, "sd-device: %s does not have an uevent file: %m", syspath);
 184                         }
 185                 } else {
 186                         /* everything else just needs to be a directory */
 187                         if (!is_dir(syspath, false))
 188                                 return -ENODEV;
 189                 }
 190         } else {
 191                 syspath = strdup(_syspath);
 192                 if (!syspath)
 193                         return -ENOMEM;
 194         }
 195
 196         devpath = syspath + STRLEN("/sys");
 197
 198         r = device_add_property_internal(device, "DEVPATH", devpath);
 199         if (r < 0)
 200                 return r;
 201
 202         free_and_replace(device->syspath, syspath);
 203
 204         device->devpath = devpath;
 205
 206         return 0;
 207 }
 208
 209 _public_ int sd_device_new_from_syspath(sd_device **ret, const char *syspath) {
 210         _cleanup_(sd_device_unrefp) sd_device *device = NULL;
 211         int r;
 212
 213         assert_return(ret, -EINVAL);
 214         assert_return(syspath, -EINVAL);
 215
 216         r = device_new_aux(&device);
 217         if (r < 0)
 218                 return r;
 219
 220         r = device_set_syspath(device, syspath, true);
 221         if (r < 0)
 222                 return r;
 223
 224         *ret = TAKE_PTR(device);
 225
 226         return 0;
 227 }
 228
 229 _public_ int sd_device_new_from_devnum(sd_device **ret, char type, dev_t devnum) {
 230         char *syspath;
 231         char id[DECIMAL_STR_MAX(unsigned) * 2 + 1];
 232
 233         assert_return(ret, -EINVAL);
 234         assert_return(IN_SET(type, 'b', 'c'), -EINVAL);
 235
 236         /* use /sys/dev/{block,char}/<maj>:<min> link */
 237         snprintf(id, sizeof(id), "%u:%u", major(devnum), minor(devnum));
 238
 239         syspath = strjoina("/sys/dev/", (type == 'b' ? "block" : "char"), "/", id);
 240
 241         return sd_device_new_from_syspath(ret, syspath);
 242 }
 243
 244 _public_ int sd_device_new_from_subsystem_sysname(sd_device **ret, const char *subsystem, const char *sysname) {
 245         char *name, *syspath;
 246         size_t len = 0;
 247
 248         assert_return(ret, -EINVAL);
 249         assert_return(subsystem, -EINVAL);
 250         assert_return(sysname, -EINVAL);
 251
 252         if (streq(subsystem, "subsystem")) {
 253                 syspath = strjoina("/sys/subsystem/", sysname);
 254                 if (access(syspath, F_OK) >= 0)
 255                         return sd_device_new_from_syspath(ret, syspath);
 256
 257                 syspath = strjoina("/sys/bus/", sysname);
 258                 if (access(syspath, F_OK) >= 0)
 259                         return sd_device_new_from_syspath(ret, syspath);
 260
 261                 syspath = strjoina("/sys/class/", sysname);
 262                 if (access(syspath, F_OK) >= 0)
 263                         return sd_device_new_from_syspath(ret, syspath);
 264         } else  if (streq(subsystem, "module")) {
 265                 syspath = strjoina("/sys/module/", sysname);
 266                 if (access(syspath, F_OK) >= 0)
 267                         return sd_device_new_from_syspath(ret, syspath);
 268         } else if (streq(subsystem, "drivers")) {
 269                 char subsys[PATH_MAX];
 270                 char *driver;
 271
 272                 strscpy(subsys, sizeof(subsys), sysname);
 273                 driver = strchr(subsys, ':');
 274                 if (driver) {
 275                         driver[0] = '\0';
 276                         driver++;
 277
 278                         syspath = strjoina("/sys/subsystem/", subsys, "/drivers/", driver);
 279                         if (access(syspath, F_OK) >= 0)
 280                                 return sd_device_new_from_syspath(ret, syspath);
 281
 282                         syspath = strjoina("/sys/bus/", subsys, "/drivers/", driver);
 283                         if (access(syspath, F_OK) >= 0)
 284                                 return sd_device_new_from_syspath(ret, syspath);
 285                 }
 286         }
 287
 288         /* translate sysname back to sysfs filename */
 289         name = strdupa(sysname);
 290         while (name[len] != '\0') {
 291                 if (name[len] == '/')
 292                         name[len] = '!';
 293
 294                 len++;
 295         }
 296
 297         syspath = strjoina("/sys/subsystem/", subsystem, "/devices/", name);
 298         if (access(syspath, F_OK) >= 0)
 299                 return sd_device_new_from_syspath(ret, syspath);
 300
 301         syspath = strjoina("/sys/bus/", subsystem, "/devices/", name);
 302         if (access(syspath, F_OK) >= 0)
 303                 return sd_device_new_from_syspath(ret, syspath);
 304
 305         syspath = strjoina("/sys/class/", subsystem, "/", name);
 306         if (access(syspath, F_OK) >= 0)
 307                 return sd_device_new_from_syspath(ret, syspath);
 308
 309         syspath = strjoina("/sys/firmware/", subsystem, "/", sysname);
 310         if (access(syspath, F_OK) >= 0)
 311                 return sd_device_new_from_syspath(ret, syspath);
 312
 313         return -ENODEV;
 314 }
 315
 316 int device_set_devtype(sd_device *device, const char *_devtype) {
 317         _cleanup_free_ char *devtype = NULL;
 318         int r;
 319
 320         assert(device);
 321         assert(_devtype);
 322
 323         devtype = strdup(_devtype);
 324         if (!devtype)
 325                 return -ENOMEM;
 326
 327         r = device_add_property_internal(device, "DEVTYPE", devtype);
 328         if (r < 0)
 329                 return r;
 330
 331         free_and_replace(device->devtype, devtype);
 332
 333         return 0;
 334 }
 335
 336 int device_set_ifindex(sd_device *device, const char *_ifindex) {
 337         int ifindex, r;
 338
 339         assert(device);
 340         assert(_ifindex);
 341
 342         r = parse_ifindex(_ifindex, &ifindex);
 343         if (r < 0)
 344                 return r;
 345
 346         r = device_add_property_internal(device, "IFINDEX", _ifindex);
 347         if (r < 0)
 348                 return r;
 349
 350         device->ifindex = ifindex;
 351
 352         return 0;
 353 }
 354
 355 int device_set_devname(sd_device *device, const char *_devname) {
 356         _cleanup_free_ char *devname = NULL;
 357         int r;
 358
 359         assert(device);
 360         assert(_devname);
 361
 362         if (_devname[0] != '/') {
 363                 r = asprintf(&devname, "/dev/%s", _devname);
 364                 if (r < 0)
 365                         return -ENOMEM;
 366         } else {
 367                 devname = strdup(_devname);
 368                 if (!devname)
 369                         return -ENOMEM;
 370         }
 371
 372         r = device_add_property_internal(device, "DEVNAME", devname);
 373         if (r < 0)
 374                 return r;
 375
 376         free_and_replace(device->devname, devname);
 377
 378         return 0;
 379 }
 380
 381 int device_set_devmode(sd_device *device, const char *_devmode) {
 382         unsigned devmode;
 383         int r;
 384
 385         assert(device);
 386         assert(_devmode);
 387
 388         r = safe_atou(_devmode, &devmode);
 389         if (r < 0)
 390                 return r;
 391
 392         if (devmode > 07777)
 393                 return -EINVAL;
 394
 395         r = device_add_property_internal(device, "DEVMODE", _devmode);
 396         if (r < 0)
 397                 return r;
 398
 399         device->devmode = devmode;
 400
 401         return 0;
 402 }
 403
 404 int device_set_devnum(sd_device *device, const char *major, const char *minor) {
 405         unsigned maj = 0, min = 0;
 406         int r;
 407
 408         assert(device);
 409         assert(major);
 410
 411         r = safe_atou(major, &maj);
 412         if (r < 0)
 413                 return r;
 414         if (!maj)
 415                 return 0;
 416
 417         if (minor) {
 418                 r = safe_atou(minor, &min);
 419                 if (r < 0)
 420                         return r;
 421         }
 422
 423         r = device_add_property_internal(device, "MAJOR", major);
 424         if (r < 0)
 425                 return r;
 426
 427         if (minor) {
 428                 r = device_add_property_internal(device, "MINOR", minor);
 429                 if (r < 0)
 430                         return r;
 431         }
 432
 433         device->devnum = makedev(maj, min);
 434
 435         return 0;
 436 }
 437
 438 static int handle_uevent_line(sd_device *device, const char *key, const char *value, const char **major, const char **minor) {
 439         int r;
 440
 441         assert(device);
 442         assert(key);
 443         assert(value);
 444         assert(major);
 445         assert(minor);
 446
 447         if (streq(key, "DEVTYPE")) {
 448                 r = device_set_devtype(device, value);
 449                 if (r < 0)
 450                         return r;
 451         } else if (streq(key, "IFINDEX")) {
 452                 r = device_set_ifindex(device, value);
 453                 if (r < 0)
 454                         return r;
 455         } else if (streq(key, "DEVNAME")) {
 456                 r = device_set_devname(device, value);
 457                 if (r < 0)
 458                         return r;
 459         } else if (streq(key, "DEVMODE")) {
 460                 r = device_set_devmode(device, value);
 461                 if (r < 0)
 462                         return r;
 463         } else if (streq(key, "MAJOR"))
 464                 *major = value;
 465         else if (streq(key, "MINOR"))
 466                 *minor = value;
 467         else {
 468                 r = device_add_property_internal(device, key, value);
 469                 if (r < 0)
 470                         return r;
 471         }
 472
 473         return 0;
 474 }
 475
 476 int device_read_uevent_file(sd_device *device) {
 477         _cleanup_free_ char *uevent = NULL;
 478         const char *syspath, *key = NULL, *value = NULL, *major = NULL, *minor = NULL;
 479         char *path;
 480         size_t uevent_len;
 481         unsigned i;
 482         int r;
 483
 484         enum {
 485                 PRE_KEY,
 486                 KEY,
 487                 PRE_VALUE,
 488                 VALUE,
 489                 INVALID_LINE,
 490         } state = PRE_KEY;
 491
 492         assert(device);
 493
 494         if (device->uevent_loaded || device->sealed)
 495                 return 0;
 496
 497         device->uevent_loaded = true;
 498
 499         r = sd_device_get_syspath(device, &syspath);
 500         if (r < 0)
 501                 return r;
 502
 503         path = strjoina(syspath, "/uevent");
 504
 505         r = read_full_file(path, &uevent, &uevent_len);
 506         if (r == -EACCES)
 507                 /* empty uevent files may be write-only */
 508                 return 0;
 509         else if (r == -ENOENT)
 510                 /* some devices may not have uevent files, see set_syspath() */
 511                 return 0;
 512         else if (r < 0)
 513                 return log_debug_errno(r, "sd-device: failed to read uevent file '%s': %m", path);
 514
 515         for (i = 0; i < uevent_len; i++)
 516                 switch (state) {
 517                 case PRE_KEY:
 518                         if (!strchr(NEWLINE, uevent[i])) {
 519                                 key = &uevent[i];
 520
 521                                 state = KEY;
 522                         }
 523
 524                         break;
 525                 case KEY:
 526                         if (uevent[i] == '=') {
 527                                 uevent[i] = '\0';
 528
 529                                 state = PRE_VALUE;
 530                         } else if (strchr(NEWLINE, uevent[i])) {
 531                                 uevent[i] = '\0';
 532                                 log_debug("sd-device: ignoring invalid uevent line '%s'", key);
 533
 534                                 state = PRE_KEY;
 535                         }
 536
 537                         break;
 538                 case PRE_VALUE:
 539                         value = &uevent[i];
 540                         state = VALUE;
 541
 542                         _fallthrough_; /* to handle empty property */
 543                 case VALUE:
 544                         if (strchr(NEWLINE, uevent[i])) {
 545                                 uevent[i] = '\0';
 546
 547                                 r = handle_uevent_line(device, key, value, &major, &minor);
 548                                 if (r < 0)
 549                                         log_debug_errno(r, "sd-device: failed to handle uevent entry '%s=%s': %m", key, value);
 550
 551                                 state = PRE_KEY;
 552                         }
 553
 554                         break;
 555                 default:
 556                         assert_not_reached("invalid state when parsing uevent file");
 557                 }
 558
 559         if (major) {
 560                 r = device_set_devnum(device, major, minor);
 561                 if (r < 0)
 562                         log_debug_errno(r, "sd-device: could not set 'MAJOR=%s' or 'MINOR=%s' from '%s': %m", major, minor, path);
 563         }
 564
 565         return 0;
 566 }
 567
 568 _public_ int sd_device_get_ifindex(sd_device *device, int *ifindex) {
 569         int r;
 570
 571         assert_return(device, -EINVAL);
 572         assert_return(ifindex, -EINVAL);
 573
 574         r = device_read_uevent_file(device);
 575         if (r < 0)
 576                 return r;
 577
 578         *ifindex = device->ifindex;
 579
 580         return 0;
 581 }
 582
 583 _public_ int sd_device_new_from_device_id(sd_device **ret, const char *id) {
 584         int r;
 585
 586         assert_return(ret, -EINVAL);
 587         assert_return(id, -EINVAL);
 588
 589         switch (id[0]) {
 590         case 'b':
 591         case 'c':
 592         {
 593                 char type;
 594                 int maj, min;
 595
 596                 r = sscanf(id, "%c%i:%i", &type, &maj, &min);
 597                 if (r != 3)
 598                         return -EINVAL;
 599
 600                 return sd_device_new_from_devnum(ret, type, makedev(maj, min));
 601         }
 602         case 'n':
 603         {
 604                 _cleanup_(sd_device_unrefp) sd_device *device = NULL;
 605                 _cleanup_close_ int sk = -1;
 606                 struct ifreq ifr = {};
 607                 int ifindex;
 608
 609                 r = parse_ifindex(&id[1], &ifr.ifr_ifindex);
 610                 if (r < 0)
 611                         return r;
 612
 613                 sk = socket_ioctl_fd();
 614                 if (sk < 0)
 615                         return sk;
 616
 617                 r = ioctl(sk, SIOCGIFNAME, &ifr);
 618                 if (r < 0)
 619                         return -errno;
 620
 621                 r = sd_device_new_from_subsystem_sysname(&device, "net", ifr.ifr_name);
 622                 if (r < 0)
 623                         return r;
 624
 625                 r = sd_device_get_ifindex(device, &ifindex);
 626                 if (r < 0)
 627                         return r;
 628
 629                 /* this is racey, so we might end up with the wrong device */
 630                 if (ifr.ifr_ifindex != ifindex)
 631                         return -ENODEV;
 632
 633                 *ret = TAKE_PTR(device);
 634
 635                 return 0;
 636         }
 637         case '+':
 638         {
 639                 char subsys[PATH_MAX];
 640                 char *sysname;
 641
 642                 (void) strscpy(subsys, sizeof(subsys), id + 1);
 643                 sysname = strchr(subsys, ':');
 644                 if (!sysname)
 645                         return -EINVAL;
 646
 647                 sysname[0] = '\0';
 648                 sysname++;
 649
 650                 return sd_device_new_from_subsystem_sysname(ret, subsys, sysname);
 651         }
 652         default:
 653                 return -EINVAL;
 654         }
 655 }
 656
 657 _public_ int sd_device_get_syspath(sd_device *device, const char **ret) {
 658         assert_return(device, -EINVAL);
 659         assert_return(ret, -EINVAL);
 660
 661         assert(path_startswith(device->syspath, "/sys/"));
 662
 663         *ret = device->syspath;
 664
 665         return 0;
 666 }
 667
 668 static int device_new_from_child(sd_device **ret, sd_device *child) {
 669         _cleanup_free_ char *path = NULL;
 670         const char *subdir, *syspath;
 671         int r;
 672
 673         assert(ret);
 674         assert(child);
 675
 676         r = sd_device_get_syspath(child, &syspath);
 677         if (r < 0)
 678                 return r;
 679
 680         path = strdup(syspath);
 681         if (!path)
 682                 return -ENOMEM;
 683         subdir = path + STRLEN("/sys");
 684
 685         for (;;) {
 686                 char *pos;
 687
 688                 pos = strrchr(subdir, '/');
 689                 if (!pos || pos < subdir + 2)
 690                         break;
 691
 692                 *pos = '\0';
 693
 694                 r = sd_device_new_from_syspath(ret, path);
 695                 if (r < 0)
 696                         continue;
 697
 698                 return 0;
 699         }
 700
 701         return -ENODEV;
 702 }
 703
 704 _public_ int sd_device_get_parent(sd_device *child, sd_device **ret) {
 705
 706         assert_return(ret, -EINVAL);
 707         assert_return(child, -EINVAL);
 708
 709         if (!child->parent_set) {
 710                 child->parent_set = true;
 711
 712                 (void) device_new_from_child(&child->parent, child);
 713         }
 714
 715         if (!child->parent)
 716                 return -ENOENT;
 717
 718         *ret = child->parent;
 719
 720         return 0;
 721 }
 722
 723 int device_set_subsystem(sd_device *device, const char *_subsystem) {
 724         _cleanup_free_ char *subsystem = NULL;
 725         int r;
 726
 727         assert(device);
 728         assert(_subsystem);
 729
 730         subsystem = strdup(_subsystem);
 731         if (!subsystem)
 732                 return -ENOMEM;
 733
 734         r = device_add_property_internal(device, "SUBSYSTEM", subsystem);
 735         if (r < 0)
 736                 return r;
 737
 738         free_and_replace(device->subsystem, subsystem);
 739
 740         device->subsystem_set = true;
 741
 742         return 0;
 743 }
 744
 745 static int device_set_drivers_subsystem(sd_device *device, const char *_subsystem) {
 746         _cleanup_free_ char *subsystem = NULL;
 747         int r;
 748
 749         assert(device);
 750         assert(_subsystem);
 751         assert(*_subsystem);
 752
 753         subsystem = strdup(_subsystem);
 754         if (!subsystem)
 755                 return -ENOMEM;
 756
 757         r = device_set_subsystem(device, "drivers");
 758         if (r < 0)
 759                 return r;
 760
 761         free_and_replace(device->driver_subsystem, subsystem);
 762
 763         return 0;
 764 }
 765
 766 _public_ int sd_device_get_subsystem(sd_device *device, const char **ret) {
 767         const char *syspath, *drivers = NULL;
 768         int r;
 769
 770         assert_return(ret, -EINVAL);
 771         assert_return(device, -EINVAL);
 772
 773         r = sd_device_get_syspath(device, &syspath);
 774         if (r < 0)
 775                 return r;
 776
 777         if (!device->subsystem_set) {
 778                 _cleanup_free_ char *subsystem = NULL;
 779                 char *path;
 780
 781                 /* read 'subsystem' link */
 782                 path = strjoina(syspath, "/subsystem");
 783                 r = readlink_value(path, &subsystem);
 784                 if (r >= 0)
 785                         r = device_set_subsystem(device, subsystem);
 786                 /* use implicit names */
 787                 else if (path_startswith(device->devpath, "/module/"))
 788                         r = device_set_subsystem(device, "module");
 789                 else if (!(drivers = strstr(syspath, "/drivers/")) &&
 790                          (path_startswith(device->devpath, "/subsystem/") ||
 791                           path_startswith(device->devpath, "/class/") ||
 792                           path_startswith(device->devpath, "/bus/")))
 793                         r = device_set_subsystem(device, "subsystem");
 794                 if (r < 0 && r != -ENOENT)
 795                         return log_debug_errno(r, "sd-device: could not set subsystem for %s: %m", device->devpath);
 796
 797                 device->subsystem_set = true;
 798         } else if (!device->driver_subsystem_set)
 799                 drivers = strstr(syspath, "/drivers/");
 800
 801         if (!device->driver_subsystem_set) {
 802                 if (drivers) {
 803                         _cleanup_free_ char *subpath = NULL;
 804
 805                         subpath = strndup(syspath, drivers - syspath);
 806                         if (!subpath)
 807                                 r = -ENOMEM;
 808                         else {
 809                                 const char *subsys;
 810
 811                                 subsys = strrchr(subpath, '/');
 812                                 if (!subsys)
 813                                         r = -EINVAL;
 814                                 else
 815                                         r = device_set_drivers_subsystem(device, subsys + 1);
 816                         }
 817                         if (r < 0 && r != -ENOENT)
 818                                 return log_debug_errno(r, "sd-device: could not set subsystem for driver %s: %m", device->devpath);
 819                 }
 820
 821                 device->driver_subsystem_set = true;
 822         }
 823
 824         if (!device->subsystem)
 825                 return -ENOENT;
 826
 827         *ret = device->subsystem;
 828
 829         return 0;
 830 }
 831
 832 _public_ int sd_device_get_devtype(sd_device *device, const char **devtype) {
 833         int r;
 834
 835         assert(devtype);
 836         assert(device);
 837
 838         r = device_read_uevent_file(device);
 839         if (r < 0)
 840                 return r;
 841
 842         *devtype = device->devtype;
 843
 844         return 0;
 845 }
 846
 847 _public_ int sd_device_get_parent_with_subsystem_devtype(sd_device *child, const char *subsystem, const char *devtype, sd_device **ret) {
 848         sd_device *parent = NULL;
 849         int r;
 850
 851         assert_return(child, -EINVAL);
 852         assert_return(subsystem, -EINVAL);
 853
 854         r = sd_device_get_parent(child, &parent);
 855         while (r >= 0) {
 856                 const char *parent_subsystem = NULL;
 857                 const char *parent_devtype = NULL;
 858
 859                 (void) sd_device_get_subsystem(parent, &parent_subsystem);
 860                 if (streq_ptr(parent_subsystem, subsystem)) {
 861                         if (!devtype)
 862                                 break;
 863
 864                         (void) sd_device_get_devtype(parent, &parent_devtype);
 865                         if (streq_ptr(parent_devtype, devtype))
 866                                 break;
 867                 }
 868                 r = sd_device_get_parent(parent, &parent);
 869         }
 870
 871         if (r < 0)
 872                 return r;
 873
 874         *ret = parent;
 875
 876         return 0;
 877 }
 878
 879 _public_ int sd_device_get_devnum(sd_device *device, dev_t *devnum) {
 880         int r;
 881
 882         assert_return(device, -EINVAL);
 883         assert_return(devnum, -EINVAL);
 884
 885         r = device_read_uevent_file(device);
 886         if (r < 0)
 887                 return r;
 888
 889         *devnum = device->devnum;
 890
 891         return 0;
 892 }
 893
 894 int device_set_driver(sd_device *device, const char *_driver) {
 895         _cleanup_free_ char *driver = NULL;
 896         int r;
 897
 898         assert(device);
 899         assert(_driver);
 900
 901         driver = strdup(_driver);
 902         if (!driver)
 903                 return -ENOMEM;
 904
 905         r = device_add_property_internal(device, "DRIVER", driver);
 906         if (r < 0)
 907                 return r;
 908
 909         free_and_replace(device->driver, driver);
 910
 911         device->driver_set = true;
 912
 913         return 0;
 914 }
 915
 916 _public_ int sd_device_get_driver(sd_device *device, const char **ret) {
 917         assert_return(device, -EINVAL);
 918         assert_return(ret, -EINVAL);
 919
 920         if (!device->driver_set) {
 921                 _cleanup_free_ char *driver = NULL;
 922                 const char *syspath;
 923                 char *path;
 924                 int r;
 925
 926                 r = sd_device_get_syspath(device, &syspath);
 927                 if (r < 0)
 928                         return r;
 929
 930                 path = strjoina(syspath, "/driver");
 931                 r = readlink_value(path, &driver);
 932                 if (r >= 0) {
 933                         r = device_set_driver(device, driver);
 934                         if (r < 0)
 935                                 return log_debug_errno(r, "sd-device: could not set driver for %s: %m", device->devpath);
 936                 } else if (r == -ENOENT)
 937                         device->driver_set = true;
 938                 else
 939                         return log_debug_errno(r, "sd-device: could not set driver for %s: %m", device->devpath);
 940         }
 941
 942         if (!device->driver)
 943                 return -ENOENT;
 944
 945         *ret = device->driver;
 946
 947         return 0;
 948 }
 949
 950 _public_ int sd_device_get_devpath(sd_device *device, const char **devpath) {
 951         assert_return(device, -EINVAL);
 952         assert_return(devpath, -EINVAL);
 953
 954         assert(device->devpath);
 955         assert(device->devpath[0] == '/');
 956
 957         *devpath = device->devpath;
 958
 959         return 0;
 960 }
 961
 962 _public_ int sd_device_get_devname(sd_device *device, const char **devname) {
 963         int r;
 964
 965         assert_return(device, -EINVAL);
 966         assert_return(devname, -EINVAL);
 967
 968         r = device_read_uevent_file(device);
 969         if (r < 0)
 970                 return r;
 971
 972         if (!device->devname)
 973                 return -ENOENT;
 974
 975         assert(path_startswith(device->devname, "/dev/"));
 976
 977         *devname = device->devname;
 978
 979         return 0;
 980 }
 981
 982 static int device_set_sysname(sd_device *device) {
 983         _cleanup_free_ char *sysname = NULL;
 984         const char *sysnum = NULL;
 985         const char *pos;
 986         size_t len = 0;
 987
 988         pos = strrchr(device->devpath, '/');
 989         if (!pos)
 990                 return -EINVAL;
 991         pos++;
 992
 993         /* devpath is not a root directory */
 994         if (*pos == '\0' || pos <= device->devpath)
 995                 return -EINVAL;
 996
 997         sysname = strdup(pos);
 998         if (!sysname)
 999                 return -ENOMEM;
1000
1001         /* some devices have '!' in their name, change that to '/' */
1002         while (sysname[len] != '\0') {
1003                 if (sysname[len] == '!')
1004                         sysname[len] = '/';
1005
1006                 len++;
1007         }
1008
1009         /* trailing number */
1010         while (len > 0 && isdigit(sysname[--len]))
1011                 sysnum = &sysname[len];
1012
1013         if (len == 0)
1014                 sysnum = NULL;
1015
1016         free_and_replace(device->sysname, sysname);
1017
1018         device->sysnum = sysnum;
1019
1020         device->sysname_set = true;
1021
1022         return 0;
1023 }
1024
1025 _public_ int sd_device_get_sysname(sd_device *device, const char **ret) {
1026         int r;
1027
1028         assert_return(device, -EINVAL);
1029         assert_return(ret, -EINVAL);
1030
1031         if (!device->sysname_set) {
1032                 r = device_set_sysname(device);
1033                 if (r < 0)
1034                         return r;
1035         }
1036
1037         assert_return(device->sysname, -ENOENT);
1038
1039         *ret = device->sysname;
1040
1041         return 0;
1042 }
1043
1044 _public_ int sd_device_get_sysnum(sd_device *device, const char **ret) {
1045         int r;
1046
1047         assert_return(device, -EINVAL);
1048         assert_return(ret, -EINVAL);
1049
1050         if (!device->sysname_set) {
1051                 r = device_set_sysname(device);
1052                 if (r < 0)
1053                         return r;
1054         }
1055
1056         *ret = device->sysnum;
1057
1058         return 0;
1059 }
1060
1061 static bool is_valid_tag(const char *tag) {
1062         assert(tag);
1063
1064         return !strchr(tag, ':') && !strchr(tag, ' ');
1065 }
1066
1067 int device_add_tag(sd_device *device, const char *tag) {
1068         int r;
1069
1070         assert(device);
1071         assert(tag);
1072
1073         if (!is_valid_tag(tag))
1074                 return -EINVAL;
1075
1076         r = set_ensure_allocated(&device->tags, &string_hash_ops);
1077         if (r < 0)
1078                 return r;
1079
1080         r = set_put_strdup(device->tags, tag);
1081         if (r < 0)
1082                 return r;
1083
1084         device->tags_generation++;
1085         device->property_tags_outdated = true;
1086
1087         return 0;
1088 }
1089
1090 int device_add_devlink(sd_device *device, const char *devlink) {
1091         int r;
1092
1093         assert(device);
1094         assert(devlink);
1095
1096         r = set_ensure_allocated(&device->devlinks, &string_hash_ops);
1097         if (r < 0)
1098                 return r;
1099
1100         r = set_put_strdup(device->devlinks, devlink);
1101         if (r < 0)
1102                 return r;
1103
1104         device->devlinks_generation++;
1105         device->property_devlinks_outdated = true;
1106
1107         return 0;
1108 }
1109
1110 static int device_add_property_internal_from_string(sd_device *device, const char *str) {
1111         _cleanup_free_ char *key = NULL;
1112         char *value;
1113
1114         assert(device);
1115         assert(str);
1116
1117         key = strdup(str);
1118         if (!key)
1119                 return -ENOMEM;
1120
1121         value = strchr(key, '=');
1122         if (!value)
1123                 return -EINVAL;
1124
1125         *value = '\0';
1126
1127         if (isempty(++value))
1128                 value = NULL;
1129
1130         return device_add_property_internal(device, key, value);
1131 }
1132
1133 int device_set_usec_initialized(sd_device *device, const char *initialized) {
1134         uint64_t usec_initialized;
1135         int r;
1136
1137         assert(device);
1138         assert(initialized);
1139
1140         r = safe_atou64(initialized, &usec_initialized);
1141         if (r < 0)
1142                 return r;
1143
1144         r = device_add_property_internal(device, "USEC_INITIALIZED", initialized);
1145         if (r < 0)
1146                 return r;
1147
1148         device->usec_initialized = usec_initialized;
1149
1150         return 0;
1151 }
1152
1153 static int handle_db_line(sd_device *device, char key, const char *value) {
1154         char *path;
1155         int r;
1156
1157         assert(device);
1158         assert(value);
1159
1160         switch (key) {
1161         case 'G':
1162                 r = device_add_tag(device, value);
1163                 if (r < 0)
1164                         return r;
1165
1166                 break;
1167         case 'S':
1168                 path = strjoina("/dev/", value);
1169                 r = device_add_devlink(device, path);
1170                 if (r < 0)
1171                         return r;
1172
1173                 break;
1174         case 'E':
1175                 r = device_add_property_internal_from_string(device, value);
1176                 if (r < 0)
1177                         return r;
1178
1179                 break;
1180         case 'I':
1181                 r = device_set_usec_initialized(device, value);
1182                 if (r < 0)
1183                         return r;
1184
1185                 break;
1186         case 'L':
1187                 r = safe_atoi(value, &device->devlink_priority);
1188                 if (r < 0)
1189                         return r;
1190
1191                 break;
1192         case 'W':
1193                 r = safe_atoi(value, &device->watch_handle);
1194                 if (r < 0)
1195                         return r;
1196
1197                 break;
1198         default:
1199                 log_debug("device db: unknown key '%c'", key);
1200         }
1201
1202         return 0;
1203 }
1204
1205 int device_get_id_filename(sd_device *device, const char **ret) {
1206         assert(device);
1207         assert(ret);
1208
1209         if (!device->id_filename) {
1210                 _cleanup_free_ char *id = NULL;
1211                 const char *subsystem;
1212                 dev_t devnum;
1213                 int ifindex, r;
1214
1215                 r = sd_device_get_subsystem(device, &subsystem);
1216                 if (r < 0)
1217                         return r;
1218
1219                 r = sd_device_get_devnum(device, &devnum);
1220                 if (r < 0)
1221                         return r;
1222
1223                 r = sd_device_get_ifindex(device, &ifindex);
1224                 if (r < 0)
1225                         return r;
1226
1227                 if (major(devnum) > 0) {
1228                         assert(subsystem);
1229
1230                         /* use dev_t — b259:131072, c254:0 */
1231                         r = asprintf(&id, "%c%u:%u",
1232                                      streq(subsystem, "block") ? 'b' : 'c',
1233                                      major(devnum), minor(devnum));
1234                         if (r < 0)
1235                                 return -ENOMEM;
1236                 } else if (ifindex > 0) {
1237                         /* use netdev ifindex — n3 */
1238                         r = asprintf(&id, "n%u", ifindex);
1239                         if (r < 0)
1240                                 return -ENOMEM;
1241                 } else {
1242                         /* use $subsys:$sysname — pci:0000:00:1f.2
1243                          * sysname() has '!' translated, get it from devpath
1244                          */
1245                         const char *sysname;
1246
1247                         sysname = basename(device->devpath);
1248                         if (!sysname)
1249                                 return -EINVAL;
1250
1251                         if (!subsystem)
1252                                 return -EINVAL;
1253
1254                         if (streq(subsystem, "drivers")) {
1255                                 /* the 'drivers' pseudo-subsystem is special, and needs the real subsystem
1256                                  * encoded as well */
1257                                 r = asprintf(&id, "+drivers:%s:%s", device->driver_subsystem, sysname);
1258                                 if (r < 0)
1259                                         return -ENOMEM;
1260                         } else {
1261                                 r = asprintf(&id, "+%s:%s", subsystem, sysname);
1262                                 if (r < 0)
1263                                         return -ENOMEM;
1264                         }
1265                 }
1266
1267                 device->id_filename = TAKE_PTR(id);
1268         }
1269
1270         *ret = device->id_filename;
1271
1272         return 0;
1273 }
1274
1275 int device_read_db_aux(sd_device *device, bool force) {
1276         _cleanup_free_ char *db = NULL;
1277         char *path;
1278         const char *id, *value;
1279         char key;
1280         size_t db_len;
1281         unsigned i;
1282         int r;
1283
1284         enum {
1285                 PRE_KEY,
1286                 KEY,
1287                 PRE_VALUE,
1288                 VALUE,
1289                 INVALID_LINE,
1290         } state = PRE_KEY;
1291
1292         if (device->db_loaded || (!force && device->sealed))
1293                 return 0;
1294
1295         device->db_loaded = true;
1296
1297         r = device_get_id_filename(device, &id);
1298         if (r < 0)
1299                 return r;
1300
1301         path = strjoina("/run/udev/data/", id);
1302
1303         r = read_full_file(path, &db, &db_len);
1304         if (r < 0) {
1305                 if (r == -ENOENT)
1306                         return 0;
1307                 else
1308                         return log_debug_errno(r, "sd-device: failed to read db '%s': %m", path);
1309         }
1310
1311         /* devices with a database entry are initialized */
1312         device->is_initialized = true;
1313
1314         for (i = 0; i < db_len; i++) {
1315                 switch (state) {
1316                 case PRE_KEY:
1317                         if (!strchr(NEWLINE, db[i])) {
1318                                 key = db[i];
1319
1320                                 state = KEY;
1321                         }
1322
1323                         break;
1324                 case KEY:
1325                         if (db[i] != ':') {
1326                                 log_debug("sd-device: ignoring invalid db entry with key '%c'", key);
1327
1328                                 state = INVALID_LINE;
1329                         } else {
1330                                 db[i] = '\0';
1331
1332                                 state = PRE_VALUE;
1333                         }
1334
1335                         break;
1336                 case PRE_VALUE:
1337                         value = &db[i];
1338
1339                         state = VALUE;
1340
1341                         break;
1342                 case INVALID_LINE:
1343                         if (strchr(NEWLINE, db[i]))
1344                                 state = PRE_KEY;
1345
1346                         break;
1347                 case VALUE:
1348                         if (strchr(NEWLINE, db[i])) {
1349                                 db[i] = '\0';
1350                                 r = handle_db_line(device, key, value);
1351                                 if (r < 0)
1352                                         log_debug_errno(r, "sd-device: failed to handle db entry '%c:%s': %m", key, value);
1353
1354                                 state = PRE_KEY;
1355                         }
1356
1357                         break;
1358                 default:
1359                         assert_not_reached("invalid state when parsing db");
1360                 }
1361         }
1362
1363         return 0;
1364 }
1365
1366 static int device_read_db(sd_device *device) {
1367         return device_read_db_aux(device, false);
1368 }
1369
1370 _public_ int sd_device_get_is_initialized(sd_device *device, int *initialized) {
1371         int r;
1372
1373         assert_return(device, -EINVAL);
1374         assert_return(initialized, -EINVAL);
1375
1376         r = device_read_db(device);
1377         if (r < 0)
1378                 return r;
1379
1380         *initialized = device->is_initialized;
1381
1382         return 0;
1383 }
1384
1385 _public_ int sd_device_get_usec_since_initialized(sd_device *device, uint64_t *usec) {
1386         usec_t now_ts;
1387         int r;
1388
1389         assert_return(device, -EINVAL);
1390         assert_return(usec, -EINVAL);
1391
1392         r = device_read_db(device);
1393         if (r < 0)
1394                 return r;
1395
1396         if (!device->is_initialized)
1397                 return -EBUSY;
1398
1399         if (!device->usec_initialized)
1400                 return -ENODATA;
1401
1402         now_ts = now(clock_boottime_or_monotonic());
1403
1404         if (now_ts < device->usec_initialized)
1405                 return -EIO;
1406
1407         *usec = now_ts - device->usec_initialized;
1408
1409         return 0;
1410 }
1411
1412 _public_ const char *sd_device_get_tag_first(sd_device *device) {
1413         void *v;
1414
1415         assert_return(device, NULL);
1416
1417         (void) device_read_db(device);
1418
1419         device->tags_iterator_generation = device->tags_generation;
1420         device->tags_iterator = ITERATOR_FIRST;
1421
1422         (void) set_iterate(device->tags, &device->tags_iterator, &v);
1423         return v;
1424 }
1425
1426 _public_ const char *sd_device_get_tag_next(sd_device *device) {
1427         void *v;
1428
1429         assert_return(device, NULL);
1430
1431         (void) device_read_db(device);
1432
1433         if (device->tags_iterator_generation != device->tags_generation)
1434                 return NULL;
1435
1436         (void) set_iterate(device->tags, &device->tags_iterator, &v);
1437         return v;
1438 }
1439
1440 _public_ const char *sd_device_get_devlink_first(sd_device *device) {
1441         void *v;
1442
1443         assert_return(device, NULL);
1444
1445         (void) device_read_db(device);
1446
1447         device->devlinks_iterator_generation = device->devlinks_generation;
1448         device->devlinks_iterator = ITERATOR_FIRST;
1449
1450         (void) set_iterate(device->devlinks, &device->devlinks_iterator, &v);
1451         return v;
1452 }
1453
1454 _public_ const char *sd_device_get_devlink_next(sd_device *device) {
1455         void *v;
1456
1457         assert_return(device, NULL);
1458
1459         (void) device_read_db(device);
1460
1461         if (device->devlinks_iterator_generation != device->devlinks_generation)
1462                 return NULL;
1463
1464         (void) set_iterate(device->devlinks, &device->devlinks_iterator, &v);
1465         return v;
1466 }
1467
1468 static int device_properties_prepare(sd_device *device) {
1469         int r;
1470
1471         assert(device);
1472
1473         r = device_read_uevent_file(device);
1474         if (r < 0)
1475                 return r;
1476
1477         r = device_read_db(device);
1478         if (r < 0)
1479                 return r;
1480
1481         if (device->property_devlinks_outdated) {
1482                 _cleanup_free_ char *devlinks = NULL;
1483                 size_t devlinks_allocated = 0, devlinks_len = 0;
1484                 const char *devlink;
1485
1486                 for (devlink = sd_device_get_devlink_first(device); devlink; devlink = sd_device_get_devlink_next(device)) {
1487                         char *e;
1488
1489                         if (!GREEDY_REALLOC(devlinks, devlinks_allocated, devlinks_len + strlen(devlink) + 2))
1490                                 return -ENOMEM;
1491                         if (devlinks_len > 0)
1492                                 stpcpy(devlinks + devlinks_len++, " ");
1493                         e = stpcpy(devlinks + devlinks_len, devlink);
1494                         devlinks_len = e - devlinks;
1495                 }
1496
1497                 r = device_add_property_internal(device, "DEVLINKS", devlinks);
1498                 if (r < 0)
1499                         return r;
1500
1501                 device->property_devlinks_outdated = false;
1502         }
1503
1504         if (device->property_tags_outdated) {
1505                 _cleanup_free_ char *tags = NULL;
1506                 size_t tags_allocated = 0, tags_len = 0;
1507                 const char *tag;
1508
1509                 if (!GREEDY_REALLOC(tags, tags_allocated, 2))
1510                         return -ENOMEM;
1511                 stpcpy(tags, ":");
1512                 tags_len++;
1513
1514                 for (tag = sd_device_get_tag_first(device); tag; tag = sd_device_get_tag_next(device)) {
1515                         char *e;
1516
1517                         if (!GREEDY_REALLOC(tags, tags_allocated, tags_len + strlen(tag) + 2))
1518                                 return -ENOMEM;
1519                         e = stpcpy(stpcpy(tags + tags_len, tag), ":");
1520                         tags_len = e - tags;
1521                 }
1522
1523                 r = device_add_property_internal(device, "TAGS", tags);
1524                 if (r < 0)
1525                         return r;
1526
1527                 device->property_tags_outdated = false;
1528         }
1529
1530         return 0;
1531 }
1532
1533 _public_ const char *sd_device_get_property_first(sd_device *device, const char **_value) {
1534         const char *key;
1535         const char *value;
1536         int r;
1537
1538         assert_return(device, NULL);
1539
1540         r = device_properties_prepare(device);
1541         if (r < 0)
1542                 return NULL;
1543
1544         device->properties_iterator_generation = device->properties_generation;
1545         device->properties_iterator = ITERATOR_FIRST;
1546
1547         ordered_hashmap_iterate(device->properties, &device->properties_iterator, (void**)&value, (const void**)&key);
1548
1549         if (_value)
1550                 *_value = value;
1551
1552         return key;
1553 }
1554
1555 _public_ const char *sd_device_get_property_next(sd_device *device, const char **_value) {
1556         const char *key;
1557         const char *value;
1558         int r;
1559
1560         assert_return(device, NULL);
1561
1562         r = device_properties_prepare(device);
1563         if (r < 0)
1564                 return NULL;
1565
1566         if (device->properties_iterator_generation != device->properties_generation)
1567                 return NULL;
1568
1569         ordered_hashmap_iterate(device->properties, &device->properties_iterator, (void**)&value, (const void**)&key);
1570
1571         if (_value)
1572                 *_value = value;
1573
1574         return key;
1575 }
1576
1577 static int device_sysattrs_read_all(sd_device *device) {
1578         _cleanup_closedir_ DIR *dir = NULL;
1579         const char *syspath;
1580         struct dirent *dent;
1581         int r;
1582
1583         assert(device);
1584
1585         if (device->sysattrs_read)
1586                 return 0;
1587
1588         r = sd_device_get_syspath(device, &syspath);
1589         if (r < 0)
1590                 return r;
1591
1592         dir = opendir(syspath);
1593         if (!dir)
1594                 return -errno;
1595
1596         r = set_ensure_allocated(&device->sysattrs, &string_hash_ops);
1597         if (r < 0)
1598                 return r;
1599
1600         FOREACH_DIRENT_ALL(dent, dir, return -errno) {
1601                 char *path;
1602                 struct stat statbuf;
1603
1604                 /* only handle symlinks and regular files */
1605                 if (!IN_SET(dent->d_type, DT_LNK, DT_REG))
1606                         continue;
1607
1608                 path = strjoina(syspath, "/", dent->d_name);
1609
1610                 if (lstat(path, &statbuf) != 0)
1611                         continue;
1612
1613                 if (!(statbuf.st_mode & S_IRUSR))
1614                         continue;
1615
1616                 r = set_put_strdup(device->sysattrs, dent->d_name);
1617                 if (r < 0)
1618                         return r;
1619         }
1620
1621         device->sysattrs_read = true;
1622
1623         return 0;
1624 }
1625
1626 _public_ const char *sd_device_get_sysattr_first(sd_device *device) {
1627         void *v;
1628         int r;
1629
1630         assert_return(device, NULL);
1631
1632         if (!device->sysattrs_read) {
1633                 r = device_sysattrs_read_all(device);
1634                 if (r < 0) {
1635                         errno = -r;
1636                         return NULL;
1637                 }
1638         }
1639
1640         device->sysattrs_iterator = ITERATOR_FIRST;
1641
1642         (void) set_iterate(device->sysattrs, &device->sysattrs_iterator, &v);
1643         return v;
1644 }
1645
1646 _public_ const char *sd_device_get_sysattr_next(sd_device *device) {
1647         void *v;
1648
1649         assert_return(device, NULL);
1650
1651         if (!device->sysattrs_read)
1652                 return NULL;
1653
1654         (void) set_iterate(device->sysattrs, &device->sysattrs_iterator, &v);
1655         return v;
1656 }
1657
1658 _public_ int sd_device_has_tag(sd_device *device, const char *tag) {
1659         assert_return(device, -EINVAL);
1660         assert_return(tag, -EINVAL);
1661
1662         (void) device_read_db(device);
1663
1664         return !!set_contains(device->tags, tag);
1665 }
1666
1667 _public_ int sd_device_get_property_value(sd_device *device, const char *key, const char **_value) {
1668         char *value;
1669         int r;
1670
1671         assert_return(device, -EINVAL);
1672         assert_return(key, -EINVAL);
1673         assert_return(_value, -EINVAL);
1674
1675         r = device_properties_prepare(device);
1676         if (r < 0)
1677                 return r;
1678
1679         value = ordered_hashmap_get(device->properties, key);
1680         if (!value)
1681                 return -ENOENT;
1682
1683         *_value = value;
1684
1685         return 0;
1686 }
1687
1688 /* replaces the value if it already exists */
1689 static int device_add_sysattr_value(sd_device *device, const char *_key, char *value) {
1690         _cleanup_free_ char *key = NULL;
1691         _cleanup_free_ char *value_old = NULL;
1692         int r;
1693
1694         assert(device);
1695         assert(_key);
1696
1697         r = hashmap_ensure_allocated(&device->sysattr_values, &string_hash_ops);
1698         if (r < 0)
1699                 return r;
1700
1701         value_old = hashmap_remove2(device->sysattr_values, _key, (void **)&key);
1702         if (!key) {
1703                 key = strdup(_key);
1704                 if (!key)
1705                         return -ENOMEM;
1706         }
1707
1708         r = hashmap_put(device->sysattr_values, key, value);
1709         if (r < 0)
1710                 return r;
1711
1712         key = NULL;
1713
1714         return 0;
1715 }
1716
1717 static int device_get_sysattr_value(sd_device *device, const char *_key, const char **_value) {
1718         const char *key = NULL, *value;
1719
1720         assert(device);
1721         assert(_key);
1722
1723         value = hashmap_get2(device->sysattr_values, _key, (void **) &key);
1724         if (!key)
1725                 return -ENOENT;
1726
1727         if (_value)
1728                 *_value = value;
1729
1730         return 0;
1731 }
1732
1733 /* We cache all sysattr lookups. If an attribute does not exist, it is stored
1734  * with a NULL value in the cache, otherwise the returned string is stored */
1735 _public_ int sd_device_get_sysattr_value(sd_device *device, const char *sysattr, const char **_value) {
1736         _cleanup_free_ char *value = NULL;
1737         const char *syspath, *cached_value = NULL;
1738         char *path;
1739         struct stat statbuf;
1740         int r;
1741
1742         assert_return(device, -EINVAL);
1743         assert_return(sysattr, -EINVAL);
1744
1745         /* look for possibly already cached result */
1746         r = device_get_sysattr_value(device, sysattr, &cached_value);
1747         if (r != -ENOENT) {
1748                 if (r < 0)
1749                         return r;
1750
1751                 if (!cached_value)
1752                         /* we looked up the sysattr before and it did not exist */
1753                         return -ENOENT;
1754
1755                 if (_value)
1756                         *_value = cached_value;
1757
1758                 return 0;
1759         }
1760
1761         r = sd_device_get_syspath(device, &syspath);
1762         if (r < 0)
1763                 return r;
1764
1765         path = strjoina(syspath, "/", sysattr);
1766         r = lstat(path, &statbuf);
1767         if (r < 0) {
1768                 /* remember that we could not access the sysattr */
1769                 r = device_add_sysattr_value(device, sysattr, NULL);
1770                 if (r < 0)
1771                         return r;
1772
1773                 return -ENOENT;
1774         } else if (S_ISLNK(statbuf.st_mode)) {
1775                 /* Some core links return only the last element of the target path,
1776                  * these are just values, the paths should not be exposed. */
1777                 if (STR_IN_SET(sysattr, "driver", "subsystem", "module")) {
1778                         r = readlink_value(path, &value);
1779                         if (r < 0)
1780                                 return r;
1781                 } else
1782                         return -EINVAL;
1783         } else if (S_ISDIR(statbuf.st_mode)) {
1784                 /* skip directories */
1785                 return -EINVAL;
1786         } else if (!(statbuf.st_mode & S_IRUSR)) {
1787                 /* skip non-readable files */
1788                 return -EPERM;
1789         } else {
1790                 size_t size;
1791
1792                 /* read attribute value */
1793                 r = read_full_file(path, &value, &size);
1794                 if (r < 0)
1795                         return r;
1796
1797                 /* drop trailing newlines */
1798                 while (size > 0 && value[--size] == '\n')
1799                         value[size] = '\0';
1800         }
1801
1802         r = device_add_sysattr_value(device, sysattr, value);
1803         if (r < 0)
1804                 return r;
1805
1806         *_value = TAKE_PTR(value);
1807
1808         return 0;
1809 }
1810
1811 static void device_remove_sysattr_value(sd_device *device, const char *_key) {
1812         _cleanup_free_ char *key = NULL;
1813         _cleanup_free_ char *value = NULL;
1814
1815         assert(device);
1816         assert(_key);
1817
1818         value = hashmap_remove2(device->sysattr_values, _key, (void **) &key);
1819
1820         return;
1821 }
1822
1823 /* set the attribute and save it in the cache. If a NULL value is passed the
1824  * attribute is cleared from the cache */
1825 _public_ int sd_device_set_sysattr_value(sd_device *device, const char *sysattr, char *_value) {
1826         _cleanup_close_ int fd = -1;
1827         _cleanup_free_ char *value = NULL;
1828         const char *syspath;
1829         char *path;
1830         size_t len = 0;
1831         ssize_t size;
1832         int r;
1833
1834         assert_return(device, -EINVAL);
1835         assert_return(sysattr, -EINVAL);
1836
1837         if (!_value) {
1838                 device_remove_sysattr_value(device, sysattr);
1839
1840                 return 0;
1841         }
1842
1843         r = sd_device_get_syspath(device, &syspath);
1844         if (r < 0)
1845                 return r;
1846
1847         path = strjoina(syspath, "/", sysattr);
1848
1849         fd = open(path, O_WRONLY | O_CLOEXEC | O_NOFOLLOW);
1850         if (fd < 0) {
1851                 if (errno == ELOOP)
1852                         return -EINVAL;
1853                 if (errno == EISDIR)
1854                         return -EISDIR;
1855
1856                 value = strdup("");
1857                 if (!value)
1858                         return -ENOMEM;
1859
1860                 r = device_add_sysattr_value(device, sysattr, value);
1861                 if (r < 0)
1862                         return r;
1863                 value = NULL;
1864
1865                 return -ENXIO;
1866         }
1867
1868         len = strlen(_value);
1869
1870         /* drop trailing newlines */
1871         while (len > 0 && _value[len - 1] == '\n')
1872                 len --;
1873
1874         /* value length is limited to 4k */
1875         if (len > 4096)
1876                 return -EINVAL;
1877
1878         value = strndup(_value, len);
1879         if (!value)
1880                 return -ENOMEM;
1881
1882         size = write(fd, value, len);
1883         if (size < 0)
1884                 return -errno;
1885
1886         if ((size_t)size != len)
1887                 return -EIO;
1888
1889         r = device_add_sysattr_value(device, sysattr, value);
1890         if (r < 0)
1891                 return r;
1892         value = NULL;
1893
1894         return 0;
1895 }