src/libudev/libudev-device.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2008-2012 Kay Sievers <kay@vrfy.org>
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <stddef.h>
  23 #include <unistd.h>
  24 #include <stdbool.h>
  25 #include <errno.h>
  26 #include <string.h>
  27 #include <dirent.h>
  28 #include <fcntl.h>
  29 #include <ctype.h>
  30 #include <net/if.h>
  31 #include <sys/stat.h>
  32 #include <sys/ioctl.h>
  33 #include <sys/socket.h>
  34 #include <linux/sockios.h>
  35
  36 #include "libudev.h"
  37 #include "libudev-private.h"
  38
  39 static int udev_device_set_devnode(struct udev_device *udev_device, const char *devnode);
  40
  41 /**
  42  * SECTION:libudev-device
  43  * @short_description: kernel sys devices
  44  *
  45  * Representation of kernel sys devices. Devices are uniquely identified
  46  * by their syspath, every device has exactly one path in the kernel sys
  47  * filesystem. Devices usually belong to a kernel subsystem, and have
  48  * a unique name inside that subsystem.
  49  */
  50
  51 /**
  52  * udev_device:
  53  *
  54  * Opaque object representing one kernel sys device.
  55  */
  56 struct udev_device {
  57         struct udev *udev;
  58         struct udev_device *parent_device;
  59         char *syspath;
  60         const char *devpath;
  61         char *sysname;
  62         const char *sysnum;
  63         char *devnode;
  64         mode_t devnode_mode;
  65         uid_t devnode_uid;
  66         gid_t devnode_gid;
  67         char *subsystem;
  68         char *devtype;
  69         char *driver;
  70         char *action;
  71         char *devpath_old;
  72         char *id_filename;
  73         char **envp;
  74         char *monitor_buf;
  75         size_t monitor_buf_len;
  76         struct udev_list devlinks_list;
  77         struct udev_list properties_list;
  78         struct udev_list sysattr_value_list;
  79         struct udev_list sysattr_list;
  80         struct udev_list tags_list;
  81         unsigned long long int seqnum;
  82         usec_t usec_initialized;
  83         int devlink_priority;
  84         int refcount;
  85         dev_t devnum;
  86         int ifindex;
  87         int watch_handle;
  88         int maj, min;
  89         bool parent_set;
  90         bool subsystem_set;
  91         bool devtype_set;
  92         bool devlinks_uptodate;
  93         bool envp_uptodate;
  94         bool tags_uptodate;
  95         bool driver_set;
  96         bool info_loaded;
  97         bool db_loaded;
  98         bool uevent_loaded;
  99         bool is_initialized;
 100         bool sysattr_list_read;
 101         bool db_persist;
 102 };
 103
 104 /**
 105  * udev_device_get_seqnum:
 106  * @udev_device: udev device
 107  *
 108  * This is only valid if the device was received through a monitor. Devices read from
 109  * sys do not have a sequence number.
 110  *
 111  * Returns: the kernel event sequence number, or 0 if there is no sequence number available.
 112  **/
 113 _public_ unsigned long long int udev_device_get_seqnum(struct udev_device *udev_device)
 114 {
 115         if (udev_device == NULL)
 116                 return 0;
 117         return udev_device->seqnum;
 118 }
 119
 120 static int udev_device_set_seqnum(struct udev_device *udev_device, unsigned long long int seqnum)
 121 {
 122         char num[32];
 123
 124         udev_device->seqnum = seqnum;
 125         snprintf(num, sizeof(num), "%llu", seqnum);
 126         udev_device_add_property(udev_device, "SEQNUM", num);
 127         return 0;
 128 }
 129
 130 int udev_device_get_ifindex(struct udev_device *udev_device)
 131 {
 132         if (!udev_device->info_loaded)
 133                 udev_device_read_uevent_file(udev_device);
 134         return udev_device->ifindex;
 135 }
 136
 137 static int udev_device_set_ifindex(struct udev_device *udev_device, int ifindex)
 138 {
 139         char num[32];
 140
 141         udev_device->ifindex = ifindex;
 142         snprintf(num, sizeof(num), "%u", ifindex);
 143         udev_device_add_property(udev_device, "IFINDEX", num);
 144         return 0;
 145 }
 146
 147 /**
 148  * udev_device_get_devnum:
 149  * @udev_device: udev device
 150  *
 151  * Get the device major/minor number.
 152  *
 153  * Returns: the dev_t number.
 154  **/
 155 _public_ dev_t udev_device_get_devnum(struct udev_device *udev_device)
 156 {
 157         if (udev_device == NULL)
 158                 return makedev(0, 0);
 159         if (!udev_device->info_loaded)
 160                 udev_device_read_uevent_file(udev_device);
 161         return udev_device->devnum;
 162 }
 163
 164 int udev_device_set_devnum(struct udev_device *udev_device, dev_t devnum)
 165 {
 166         char num[32];
 167
 168         udev_device->devnum = devnum;
 169
 170         snprintf(num, sizeof(num), "%u", major(devnum));
 171         udev_device_add_property(udev_device, "MAJOR", num);
 172         snprintf(num, sizeof(num), "%u", minor(devnum));
 173         udev_device_add_property(udev_device, "MINOR", num);
 174         return 0;
 175 }
 176
 177 const char *udev_device_get_devpath_old(struct udev_device *udev_device)
 178 {
 179         return udev_device->devpath_old;
 180 }
 181
 182 static int udev_device_set_devpath_old(struct udev_device *udev_device, const char *devpath_old)
 183 {
 184         const char *pos;
 185
 186         free(udev_device->devpath_old);
 187         udev_device->devpath_old = strdup(devpath_old);
 188         if (udev_device->devpath_old == NULL)
 189                 return -ENOMEM;
 190         udev_device_add_property(udev_device, "DEVPATH_OLD", udev_device->devpath_old);
 191
 192         pos = strrchr(udev_device->devpath_old, '/');
 193         if (pos == NULL)
 194                 return -EINVAL;
 195         return 0;
 196 }
 197
 198 /**
 199  * udev_device_get_driver:
 200  * @udev_device: udev device
 201  *
 202  * Get the kernel driver name.
 203  *
 204  * Returns: the driver name string, or #NULL if there is no driver attached.
 205  **/
 206 _public_ const char *udev_device_get_driver(struct udev_device *udev_device)
 207 {
 208         char driver[UTIL_NAME_SIZE];
 209
 210         if (udev_device == NULL)
 211                 return NULL;
 212         if (!udev_device->driver_set) {
 213                 udev_device->driver_set = true;
 214                 if (util_get_sys_core_link_value(udev_device->udev, "driver", udev_device->syspath, driver, sizeof(driver)) > 0)
 215                         udev_device->driver = strdup(driver);
 216         }
 217         return udev_device->driver;
 218 }
 219
 220 static int udev_device_set_driver(struct udev_device *udev_device, const char *driver)
 221 {
 222         free(udev_device->driver);
 223         udev_device->driver = strdup(driver);
 224         if (udev_device->driver == NULL)
 225                 return -ENOMEM;
 226         udev_device->driver_set = true;
 227         udev_device_add_property(udev_device, "DRIVER", udev_device->driver);
 228         return 0;
 229 }
 230
 231 /**
 232  * udev_device_get_devtype:
 233  * @udev_device: udev device
 234  *
 235  * Retrieve the devtype string of the udev device.
 236  *
 237  * Returns: the devtype name of the udev device, or #NULL if it can not be determined
 238  **/
 239 _public_ const char *udev_device_get_devtype(struct udev_device *udev_device)
 240 {
 241         if (udev_device == NULL)
 242                 return NULL;
 243         if (!udev_device->devtype_set) {
 244                 udev_device->devtype_set = true;
 245                 udev_device_read_uevent_file(udev_device);
 246         }
 247         return udev_device->devtype;
 248 }
 249
 250 static int udev_device_set_devtype(struct udev_device *udev_device, const char *devtype)
 251 {
 252         free(udev_device->devtype);
 253         udev_device->devtype = strdup(devtype);
 254         if (udev_device->devtype == NULL)
 255                 return -ENOMEM;
 256         udev_device->devtype_set = true;
 257         udev_device_add_property(udev_device, "DEVTYPE", udev_device->devtype);
 258         return 0;
 259 }
 260
 261 int udev_device_set_subsystem(struct udev_device *udev_device, const char *subsystem)
 262 {
 263         free(udev_device->subsystem);
 264         udev_device->subsystem = strdup(subsystem);
 265         if (udev_device->subsystem == NULL)
 266                 return -ENOMEM;
 267         udev_device->subsystem_set = true;
 268         udev_device_add_property(udev_device, "SUBSYSTEM", udev_device->subsystem);
 269         return 0;
 270 }
 271
 272 /**
 273  * udev_device_get_subsystem:
 274  * @udev_device: udev device
 275  *
 276  * Retrieve the subsystem string of the udev device. The string does not
 277  * contain any "/".
 278  *
 279  * Returns: the subsystem name of the udev device, or #NULL if it can not be determined
 280  **/
 281 _public_ const char *udev_device_get_subsystem(struct udev_device *udev_device)
 282 {
 283         char subsystem[UTIL_NAME_SIZE];
 284
 285         if (udev_device == NULL)
 286                 return NULL;
 287         if (!udev_device->subsystem_set) {
 288                 udev_device->subsystem_set = true;
 289                 /* read "subsystem" link */
 290                 if (util_get_sys_core_link_value(udev_device->udev, "subsystem", udev_device->syspath, subsystem, sizeof(subsystem)) > 0) {
 291                         udev_device_set_subsystem(udev_device, subsystem);
 292                         return udev_device->subsystem;
 293                 }
 294                 /* implicit names */
 295                 if (startswith(udev_device->devpath, "/module/")) {
 296                         udev_device_set_subsystem(udev_device, "module");
 297                         return udev_device->subsystem;
 298                 }
 299                 if (strstr(udev_device->devpath, "/drivers/") != NULL) {
 300                         udev_device_set_subsystem(udev_device, "drivers");
 301                         return udev_device->subsystem;
 302                 }
 303                 if (startswith(udev_device->devpath, "/subsystem/") ||
 304                     startswith(udev_device->devpath, "/class/") ||
 305                     startswith(udev_device->devpath, "/bus/")) {
 306                         udev_device_set_subsystem(udev_device, "subsystem");
 307                         return udev_device->subsystem;
 308                 }
 309         }
 310         return udev_device->subsystem;
 311 }
 312
 313 mode_t udev_device_get_devnode_mode(struct udev_device *udev_device)
 314 {
 315         if (!udev_device->info_loaded)
 316                 udev_device_read_uevent_file(udev_device);
 317         return udev_device->devnode_mode;
 318 }
 319
 320 static int udev_device_set_devnode_mode(struct udev_device *udev_device, mode_t mode)
 321 {
 322         char num[32];
 323
 324         udev_device->devnode_mode = mode;
 325         snprintf(num, sizeof(num), "%#o", mode);
 326         udev_device_add_property(udev_device, "DEVMODE", num);
 327         return 0;
 328 }
 329
 330 uid_t udev_device_get_devnode_uid(struct udev_device *udev_device)
 331 {
 332         if (!udev_device->info_loaded)
 333                 udev_device_read_uevent_file(udev_device);
 334         return udev_device->devnode_uid;
 335 }
 336
 337 static int udev_device_set_devnode_uid(struct udev_device *udev_device, uid_t uid)
 338 {
 339         char num[32];
 340
 341         udev_device->devnode_uid = uid;
 342         snprintf(num, sizeof(num), "%u", uid);
 343         udev_device_add_property(udev_device, "DEVUID", num);
 344         return 0;
 345 }
 346
 347 gid_t udev_device_get_devnode_gid(struct udev_device *udev_device)
 348 {
 349         if (!udev_device->info_loaded)
 350                 udev_device_read_uevent_file(udev_device);
 351         return udev_device->devnode_gid;
 352 }
 353
 354 static int udev_device_set_devnode_gid(struct udev_device *udev_device, gid_t gid)
 355 {
 356         char num[32];
 357
 358         udev_device->devnode_gid = gid;
 359         snprintf(num, sizeof(num), "%u", gid);
 360         udev_device_add_property(udev_device, "DEVGID", num);
 361         return 0;
 362 }
 363
 364 struct udev_list_entry *udev_device_add_property(struct udev_device *udev_device, const char *key, const char *value)
 365 {
 366         udev_device->envp_uptodate = false;
 367         if (value == NULL) {
 368                 struct udev_list_entry *list_entry;
 369
 370                 list_entry = udev_device_get_properties_list_entry(udev_device);
 371                 list_entry = udev_list_entry_get_by_name(list_entry, key);
 372                 if (list_entry != NULL)
 373                         udev_list_entry_delete(list_entry);
 374                 return NULL;
 375         }
 376         return udev_list_entry_add(&udev_device->properties_list, key, value);
 377 }
 378
 379 static struct udev_list_entry *udev_device_add_property_from_string(struct udev_device *udev_device, const char *property)
 380 {
 381         char name[UTIL_LINE_SIZE];
 382         char *val;
 383
 384         strscpy(name, sizeof(name), property);
 385         val = strchr(name, '=');
 386         if (val == NULL)
 387                 return NULL;
 388         val[0] = '\0';
 389         val = &val[1];
 390         if (val[0] == '\0')
 391                 val = NULL;
 392         return udev_device_add_property(udev_device, name, val);
 393 }
 394
 395 /*
 396  * parse property string, and if needed, update internal values accordingly
 397  *
 398  * udev_device_add_property_from_string_parse_finish() needs to be
 399  * called after adding properties, and its return value checked
 400  *
 401  * udev_device_set_info_loaded() needs to be set, to avoid trying
 402  * to use a device without a DEVPATH set
 403  */
 404 void udev_device_add_property_from_string_parse(struct udev_device *udev_device, const char *property)
 405 {
 406         if (startswith(property, "DEVPATH=")) {
 407                 char path[UTIL_PATH_SIZE];
 408
 409                 strscpyl(path, sizeof(path), "/sys", &property[8], NULL);
 410                 udev_device_set_syspath(udev_device, path);
 411         } else if (startswith(property, "SUBSYSTEM=")) {
 412                 udev_device_set_subsystem(udev_device, &property[10]);
 413         } else if (startswith(property, "DEVTYPE=")) {
 414                 udev_device_set_devtype(udev_device, &property[8]);
 415         } else if (startswith(property, "DEVNAME=")) {
 416                 udev_device_set_devnode(udev_device, &property[8]);
 417         } else if (startswith(property, "DEVLINKS=")) {
 418                 char devlinks[UTIL_PATH_SIZE];
 419                 char *slink;
 420                 char *next;
 421
 422                 strscpy(devlinks, sizeof(devlinks), &property[9]);
 423                 slink = devlinks;
 424                 next = strchr(slink, ' ');
 425                 while (next != NULL) {
 426                         next[0] = '\0';
 427                         udev_device_add_devlink(udev_device, slink);
 428                         slink = &next[1];
 429                         next = strchr(slink, ' ');
 430                 }
 431                 if (slink[0] != '\0')
 432                         udev_device_add_devlink(udev_device, slink);
 433         } else if (startswith(property, "TAGS=")) {
 434                 char tags[UTIL_PATH_SIZE];
 435                 char *next;
 436
 437                 strscpy(tags, sizeof(tags), &property[5]);
 438                 next = strchr(tags, ':');
 439                 if (next != NULL) {
 440                         next++;
 441                         while (next[0] != '\0') {
 442                                 char *tag;
 443
 444                                 tag = next;
 445                                 next = strchr(tag, ':');
 446                                 if (next == NULL)
 447                                         break;
 448                                 next[0] = '\0';
 449                                 next++;
 450                                 udev_device_add_tag(udev_device, tag);
 451                         }
 452                 }
 453         } else if (startswith(property, "USEC_INITIALIZED=")) {
 454                 udev_device_set_usec_initialized(udev_device, strtoull(&property[19], NULL, 10));
 455         } else if (startswith(property, "DRIVER=")) {
 456                 udev_device_set_driver(udev_device, &property[7]);
 457         } else if (startswith(property, "ACTION=")) {
 458                 udev_device_set_action(udev_device, &property[7]);
 459         } else if (startswith(property, "MAJOR=")) {
 460                 udev_device->maj = strtoull(&property[6], NULL, 10);
 461         } else if (startswith(property, "MINOR=")) {
 462                 udev_device->min = strtoull(&property[6], NULL, 10);
 463         } else if (startswith(property, "DEVPATH_OLD=")) {
 464                 udev_device_set_devpath_old(udev_device, &property[12]);
 465         } else if (startswith(property, "SEQNUM=")) {
 466                 udev_device_set_seqnum(udev_device, strtoull(&property[7], NULL, 10));
 467         } else if (startswith(property, "IFINDEX=")) {
 468                 udev_device_set_ifindex(udev_device, strtoull(&property[8], NULL, 10));
 469         } else if (startswith(property, "DEVMODE=")) {
 470                 udev_device_set_devnode_mode(udev_device, strtoul(&property[8], NULL, 8));
 471         } else if (startswith(property, "DEVUID=")) {
 472                 udev_device_set_devnode_uid(udev_device, strtoul(&property[7], NULL, 10));
 473         } else if (startswith(property, "DEVGID=")) {
 474                 udev_device_set_devnode_gid(udev_device, strtoul(&property[7], NULL, 10));
 475         } else {
 476                 udev_device_add_property_from_string(udev_device, property);
 477         }
 478 }
 479
 480 int udev_device_add_property_from_string_parse_finish(struct udev_device *udev_device)
 481 {
 482         if (udev_device->maj > 0)
 483                 udev_device_set_devnum(udev_device, makedev(udev_device->maj, udev_device->min));
 484         udev_device->maj = 0;
 485         udev_device->min = 0;
 486
 487         if (udev_device->devpath == NULL || udev_device->subsystem == NULL)
 488                 return -EINVAL;
 489         return 0;
 490 }
 491
 492 /**
 493  * udev_device_get_property_value:
 494  * @udev_device: udev device
 495  * @key: property name
 496  *
 497  * Get the value of a given property.
 498  *
 499  * Returns: the property string, or #NULL if there is no such property.
 500  **/
 501 _public_ const char *udev_device_get_property_value(struct udev_device *udev_device, const char *key)
 502 {
 503         struct udev_list_entry *list_entry;
 504
 505         if (udev_device == NULL)
 506                 return NULL;
 507         if (key == NULL)
 508                 return NULL;
 509
 510         list_entry = udev_device_get_properties_list_entry(udev_device);
 511         list_entry = udev_list_entry_get_by_name(list_entry, key);
 512         return udev_list_entry_get_value(list_entry);
 513 }
 514
 515 int udev_device_read_db(struct udev_device *udev_device, const char *dbfile)
 516 {
 517         char filename[UTIL_PATH_SIZE];
 518         char line[UTIL_LINE_SIZE];
 519         FILE *f;
 520
 521         /* providing a database file will always force-load it */
 522         if (dbfile == NULL) {
 523                 const char *id;
 524
 525                 if (udev_device->db_loaded)
 526                         return 0;
 527                 udev_device->db_loaded = true;
 528
 529                 id = udev_device_get_id_filename(udev_device);
 530                 if (id == NULL)
 531                         return -1;
 532                 strscpyl(filename, sizeof(filename), "/run/udev/data/", id, NULL);
 533                 dbfile = filename;
 534         }
 535
 536         f = fopen(dbfile, "re");
 537         if (f == NULL)
 538                 return log_debug_errno(errno, "no db file to read %s: %m", dbfile);
 539
 540         /* devices with a database entry are initialized */
 541         udev_device->is_initialized = true;
 542
 543         while (fgets(line, sizeof(line), f)) {
 544                 ssize_t len;
 545                 const char *val;
 546                 struct udev_list_entry *entry;
 547
 548                 len = strlen(line);
 549                 if (len < 4)
 550                         break;
 551                 line[len-1] = '\0';
 552                 val = &line[2];
 553                 switch(line[0]) {
 554                 case 'S':
 555                         strscpyl(filename, sizeof(filename), "/dev/", val, NULL);
 556                         udev_device_add_devlink(udev_device, filename);
 557                         break;
 558                 case 'L':
 559                         udev_device_set_devlink_priority(udev_device, atoi(val));
 560                         break;
 561                 case 'E':
 562                         entry = udev_device_add_property_from_string(udev_device, val);
 563                         udev_list_entry_set_num(entry, true);
 564                         break;
 565                 case 'G':
 566                         udev_device_add_tag(udev_device, val);
 567                         break;
 568                 case 'W':
 569                         udev_device_set_watch_handle(udev_device, atoi(val));
 570                         break;
 571                 case 'I':
 572                         udev_device_set_usec_initialized(udev_device, strtoull(val, NULL, 10));
 573                         break;
 574                 }
 575         }
 576         fclose(f);
 577
 578         log_debug("device %p filled with db file data", udev_device);
 579         return 0;
 580 }
 581
 582 int udev_device_read_uevent_file(struct udev_device *udev_device)
 583 {
 584         char filename[UTIL_PATH_SIZE];
 585         FILE *f;
 586         char line[UTIL_LINE_SIZE];
 587         int maj = 0;
 588         int min = 0;
 589
 590         if (udev_device->uevent_loaded)
 591                 return 0;
 592
 593         strscpyl(filename, sizeof(filename), udev_device->syspath, "/uevent", NULL);
 594         f = fopen(filename, "re");
 595         if (f == NULL)
 596                 return -errno;
 597         udev_device->uevent_loaded = true;
 598
 599         while (fgets(line, sizeof(line), f)) {
 600                 char *pos;
 601
 602                 pos = strchr(line, '\n');
 603                 if (pos == NULL)
 604                         continue;
 605                 pos[0] = '\0';
 606
 607                 if (startswith(line, "DEVTYPE=")) {
 608                         udev_device_set_devtype(udev_device, &line[8]);
 609                         continue;
 610                 }
 611                 if (startswith(line, "IFINDEX=")) {
 612                         udev_device_set_ifindex(udev_device, strtoull(&line[8], NULL, 10));
 613                         continue;
 614                 }
 615                 if (startswith(line, "DEVNAME=")) {
 616                         udev_device_set_devnode(udev_device, &line[8]);
 617                         continue;
 618                 }
 619
 620                 if (startswith(line, "MAJOR="))
 621                         maj = strtoull(&line[6], NULL, 10);
 622                 else if (startswith(line, "MINOR="))
 623                         min = strtoull(&line[6], NULL, 10);
 624                 else if (startswith(line, "DEVMODE="))
 625                         udev_device->devnode_mode = strtoul(&line[8], NULL, 8);
 626
 627                 udev_device_add_property_from_string(udev_device, line);
 628         }
 629
 630         udev_device->devnum = makedev(maj, min);
 631         fclose(f);
 632         return 0;
 633 }
 634
 635 void udev_device_set_info_loaded(struct udev_device *device)
 636 {
 637         device->info_loaded = true;
 638 }
 639
 640 struct udev_device *udev_device_new(struct udev *udev)
 641 {
 642         struct udev_device *udev_device;
 643
 644         if (udev == NULL) {
 645                 errno = EINVAL;
 646                 return NULL;
 647         }
 648
 649         udev_device = new0(struct udev_device, 1);
 650         if (udev_device == NULL) {
 651                 errno = ENOMEM;
 652                 return NULL;
 653         }
 654         udev_device->refcount = 1;
 655         udev_device->udev = udev;
 656         udev_list_init(udev, &udev_device->devlinks_list, true);
 657         udev_list_init(udev, &udev_device->properties_list, true);
 658         udev_list_init(udev, &udev_device->sysattr_value_list, true);
 659         udev_list_init(udev, &udev_device->sysattr_list, false);
 660         udev_list_init(udev, &udev_device->tags_list, true);
 661         udev_device->watch_handle = -1;
 662
 663         return udev_device;
 664 }
 665
 666 /**
 667  * udev_device_new_from_syspath:
 668  * @udev: udev library context
 669  * @syspath: sys device path including sys directory
 670  *
 671  * Create new udev device, and fill in information from the sys
 672  * device and the udev database entry. The syspath is the absolute
 673  * path to the device, including the sys mount point.
 674  *
 675  * The initial refcount is 1, and needs to be decremented to
 676  * release the resources of the udev device.
 677  *
 678  * Returns: a new udev device, or #NULL, if it does not exist
 679  **/
 680 _public_ struct udev_device *udev_device_new_from_syspath(struct udev *udev, const char *syspath)
 681 {
 682         const char *subdir;
 683         char path[UTIL_PATH_SIZE];
 684         char *pos;
 685         struct stat statbuf;
 686         struct udev_device *udev_device;
 687
 688         if (udev == NULL) {
 689                 errno = EINVAL;
 690                 return NULL;
 691         }
 692
 693         if (syspath == NULL) {
 694                 errno = EINVAL;
 695                 return NULL;
 696         }
 697
 698         /* path starts in sys */
 699         if (!startswith(syspath, "/sys")) {
 700                 log_debug("not in sys :%s", syspath);
 701                 errno = EINVAL;
 702                 return NULL;
 703         }
 704
 705         /* path is not a root directory */
 706         subdir = syspath + strlen("/sys");
 707         pos = strrchr(subdir, '/');
 708         if (pos == NULL || pos[1] == '\0' || pos < &subdir[2]) {
 709                 errno = EINVAL;
 710                 return NULL;
 711         }
 712
 713         /* resolve possible symlink to real path */
 714         strscpy(path, sizeof(path), syspath);
 715         util_resolve_sys_link(udev, path, sizeof(path));
 716
 717         if (startswith(path + strlen("/sys"), "/devices/")) {
 718                 char file[UTIL_PATH_SIZE];
 719
 720                 /* all "devices" require a "uevent" file */
 721                 strscpyl(file, sizeof(file), path, "/uevent", NULL);
 722                 if (stat(file, &statbuf) != 0)
 723                         return NULL;
 724         } else {
 725                 /* everything else just needs to be a directory */
 726                 if (stat(path, &statbuf) != 0 || !S_ISDIR(statbuf.st_mode))
 727                         return NULL;
 728         }
 729
 730         udev_device = udev_device_new(udev);
 731         if (udev_device == NULL)
 732                 return NULL;
 733
 734         udev_device_set_syspath(udev_device, path);
 735         log_debug("device %p has devpath '%s'", udev_device, udev_device_get_devpath(udev_device));
 736
 737         return udev_device;
 738 }
 739
 740 /**
 741  * udev_device_new_from_devnum:
 742  * @udev: udev library context
 743  * @type: char or block device
 744  * @devnum: device major/minor number
 745  *
 746  * Create new udev device, and fill in information from the sys
 747  * device and the udev database entry. The device is looked-up
 748  * by its major/minor number and type. Character and block device
 749  * numbers are not unique across the two types.
 750  *
 751  * The initial refcount is 1, and needs to be decremented to
 752  * release the resources of the udev device.
 753  *
 754  * Returns: a new udev device, or #NULL, if it does not exist
 755  **/
 756 _public_ struct udev_device *udev_device_new_from_devnum(struct udev *udev, char type, dev_t devnum)
 757 {
 758         char path[UTIL_PATH_SIZE];
 759         const char *type_str;
 760
 761         if (type == 'b')
 762                 type_str = "block";
 763         else if (type == 'c')
 764                 type_str = "char";
 765         else {
 766                 errno = EINVAL;
 767                 return NULL;
 768         }
 769
 770         /* use /sys/dev/{block,char}/<maj>:<min> link */
 771         snprintf(path, sizeof(path), "/sys/dev/%s/%u:%u",
 772                  type_str, major(devnum), minor(devnum));
 773         return udev_device_new_from_syspath(udev, path);
 774 }
 775
 776 /**
 777  * udev_device_new_from_device_id:
 778  * @udev: udev library context
 779  * @id: text string identifying a kernel device
 780  *
 781  * Create new udev device, and fill in information from the sys
 782  * device and the udev database entry. The device is looked-up
 783  * by a special string:
 784  *   b8:2          - block device major:minor
 785  *   c128:1        - char device major:minor
 786  *   n3            - network device ifindex
 787  *   +sound:card29 - kernel driver core subsystem:device name
 788  *
 789  * The initial refcount is 1, and needs to be decremented to
 790  * release the resources of the udev device.
 791  *
 792  * Returns: a new udev device, or #NULL, if it does not exist
 793  **/
 794 _public_ struct udev_device *udev_device_new_from_device_id(struct udev *udev, const char *id)
 795 {
 796         char type;
 797         int maj, min;
 798         char subsys[UTIL_PATH_SIZE];
 799         char *sysname;
 800
 801         switch(id[0]) {
 802         case 'b':
 803         case 'c':
 804                 if (sscanf(id, "%c%i:%i", &type, &maj, &min) != 3)
 805                         return NULL;
 806                 return udev_device_new_from_devnum(udev, type, makedev(maj, min));
 807         case 'n': {
 808                 int sk;
 809                 struct ifreq ifr;
 810                 struct udev_device *dev;
 811                 int ifindex;
 812
 813                 ifindex = strtoul(&id[1], NULL, 10);
 814                 if (ifindex <= 0) {
 815                         errno = EINVAL;
 816                         return NULL;
 817                 }
 818
 819                 sk = socket(PF_INET, SOCK_DGRAM, 0);
 820                 if (sk < 0)
 821                         return NULL;
 822                 memzero(&ifr, sizeof(struct ifreq));
 823                 ifr.ifr_ifindex = ifindex;
 824                 if (ioctl(sk, SIOCGIFNAME, &ifr) != 0) {
 825                         close(sk);
 826                         return NULL;
 827                 }
 828                 close(sk);
 829
 830                 dev = udev_device_new_from_subsystem_sysname(udev, "net", ifr.ifr_name);
 831                 if (dev == NULL)
 832                         return NULL;
 833                 if (udev_device_get_ifindex(dev) == ifindex)
 834                         return dev;
 835
 836                 /* this is racy, so we may end up with the wrong device */
 837                 udev_device_unref(dev);
 838                 errno = ENODEV;
 839                 return NULL;
 840         }
 841         case '+':
 842                 strscpy(subsys, sizeof(subsys), &id[1]);
 843                 sysname = strchr(subsys, ':');
 844                 if (sysname == NULL) {
 845                         errno = EINVAL;
 846                         return NULL;
 847                 }
 848                 sysname[0] = '\0';
 849                 sysname = &sysname[1];
 850                 return udev_device_new_from_subsystem_sysname(udev, subsys, sysname);
 851         default:
 852                 errno = EINVAL;
 853                 return NULL;
 854         }
 855 }
 856
 857 /**
 858  * udev_device_new_from_subsystem_sysname:
 859  * @udev: udev library context
 860  * @subsystem: the subsystem of the device
 861  * @sysname: the name of the device
 862  *
 863  * Create new udev device, and fill in information from the sys device
 864  * and the udev database entry. The device is looked up by the subsystem
 865  * and name string of the device, like "mem" / "zero", or "block" / "sda".
 866  *
 867  * The initial refcount is 1, and needs to be decremented to
 868  * release the resources of the udev device.
 869  *
 870  * Returns: a new udev device, or #NULL, if it does not exist
 871  **/
 872 _public_ struct udev_device *udev_device_new_from_subsystem_sysname(struct udev *udev, const char *subsystem, const char *sysname)
 873 {
 874         char path[UTIL_PATH_SIZE];
 875         struct stat statbuf;
 876
 877         if (streq(subsystem, "subsystem")) {
 878                 strscpyl(path, sizeof(path), "/sys/subsystem/", sysname, NULL);
 879                 if (stat(path, &statbuf) == 0)
 880                         goto found;
 881
 882                 strscpyl(path, sizeof(path), "/sys/bus/", sysname, NULL);
 883                 if (stat(path, &statbuf) == 0)
 884                         goto found;
 885
 886                 strscpyl(path, sizeof(path), "/sys/class/", sysname, NULL);
 887                 if (stat(path, &statbuf) == 0)
 888                         goto found;
 889                 goto out;
 890         }
 891
 892         if (streq(subsystem, "module")) {
 893                 strscpyl(path, sizeof(path), "/sys/module/", sysname, NULL);
 894                 if (stat(path, &statbuf) == 0)
 895                         goto found;
 896                 goto out;
 897         }
 898
 899         if (streq(subsystem, "drivers")) {
 900                 char subsys[UTIL_NAME_SIZE];
 901                 char *driver;
 902
 903                 strscpy(subsys, sizeof(subsys), sysname);
 904                 driver = strchr(subsys, ':');
 905                 if (driver != NULL) {
 906                         driver[0] = '\0';
 907                         driver = &driver[1];
 908
 909                         strscpyl(path, sizeof(path), "/sys/subsystem/", subsys, "/drivers/", driver, NULL);
 910                         if (stat(path, &statbuf) == 0)
 911                                 goto found;
 912
 913                         strscpyl(path, sizeof(path), "/sys/bus/", subsys, "/drivers/", driver, NULL);
 914                         if (stat(path, &statbuf) == 0)
 915                                 goto found;
 916                 } else
 917                         errno = EINVAL;
 918
 919                 goto out;
 920         }
 921
 922         strscpyl(path, sizeof(path), "/sys/subsystem/", subsystem, "/devices/", sysname, NULL);
 923         if (stat(path, &statbuf) == 0)
 924                 goto found;
 925
 926         strscpyl(path, sizeof(path), "/sys/bus/", subsystem, "/devices/", sysname, NULL);
 927         if (stat(path, &statbuf) == 0)
 928                 goto found;
 929
 930         strscpyl(path, sizeof(path), "/sys/class/", subsystem, "/", sysname, NULL);
 931         if (stat(path, &statbuf) == 0)
 932                 goto found;
 933 out:
 934         return NULL;
 935 found:
 936         return udev_device_new_from_syspath(udev, path);
 937 }
 938
 939 /**
 940  * udev_device_new_from_environment
 941  * @udev: udev library context
 942  *
 943  * Create new udev device, and fill in information from the
 944  * current process environment. This only works reliable if
 945  * the process is called from a udev rule. It is usually used
 946  * for tools executed from IMPORT= rules.
 947  *
 948  * The initial refcount is 1, and needs to be decremented to
 949  * release the resources of the udev device.
 950  *
 951  * Returns: a new udev device, or #NULL, if it does not exist
 952  **/
 953 _public_ struct udev_device *udev_device_new_from_environment(struct udev *udev)
 954 {
 955         int i;
 956         struct udev_device *udev_device;
 957
 958         udev_device = udev_device_new(udev);
 959         if (udev_device == NULL)
 960                 return NULL;
 961         udev_device_set_info_loaded(udev_device);
 962
 963         for (i = 0; environ[i] != NULL; i++)
 964                 udev_device_add_property_from_string_parse(udev_device, environ[i]);
 965
 966         if (udev_device_add_property_from_string_parse_finish(udev_device) < 0) {
 967                 log_debug("missing values, invalid device");
 968                 udev_device_unref(udev_device);
 969                 udev_device = NULL;
 970         }
 971
 972         return udev_device;
 973 }
 974
 975 static struct udev_device *device_new_from_parent(struct udev_device *udev_device)
 976 {
 977         struct udev_device *udev_device_parent = NULL;
 978         char path[UTIL_PATH_SIZE];
 979         const char *subdir;
 980
 981         strscpy(path, sizeof(path), udev_device->syspath);
 982         subdir = path + strlen("/sys/");
 983         for (;;) {
 984                 char *pos;
 985
 986                 pos = strrchr(subdir, '/');
 987                 if (pos == NULL || pos < &subdir[2])
 988                         break;
 989                 pos[0] = '\0';
 990                 udev_device_parent = udev_device_new_from_syspath(udev_device->udev, path);
 991                 if (udev_device_parent != NULL)
 992                         return udev_device_parent;
 993         }
 994
 995         errno = ENOENT;
 996         return NULL;
 997 }
 998
 999 /**
1000  * udev_device_get_parent:
1001  * @udev_device: the device to start searching from
1002  *
1003  * Find the next parent device, and fill in information from the sys
1004  * device and the udev database entry.
1005  *
1006  * Returned device is not referenced. It is attached to the child
1007  * device, and will be cleaned up when the child device is cleaned up.
1008  *
1009  * It is not necessarily just the upper level directory, empty or not
1010  * recognized sys directories are ignored.
1011  *
1012  * It can be called as many times as needed, without caring about
1013  * references.
1014  *
1015  * Returns: a new udev device, or #NULL, if it no parent exist.
1016  **/
1017 _public_ struct udev_device *udev_device_get_parent(struct udev_device *udev_device)
1018 {
1019         if (udev_device == NULL) {
1020                 errno = EINVAL;
1021                 return NULL;
1022         }
1023         if (!udev_device->parent_set) {
1024                 udev_device->parent_set = true;
1025                 udev_device->parent_device = device_new_from_parent(udev_device);
1026         }
1027         return udev_device->parent_device;
1028 }
1029
1030 /**
1031  * udev_device_get_parent_with_subsystem_devtype:
1032  * @udev_device: udev device to start searching from
1033  * @subsystem: the subsystem of the device
1034  * @devtype: the type (DEVTYPE) of the device
1035  *
1036  * Find the next parent device, with a matching subsystem and devtype
1037  * value, and fill in information from the sys device and the udev
1038  * database entry.
1039  *
1040  * If devtype is #NULL, only subsystem is checked, and any devtype will
1041  * match.
1042  *
1043  * Returned device is not referenced. It is attached to the child
1044  * device, and will be cleaned up when the child device is cleaned up.
1045  *
1046  * It can be called as many times as needed, without caring about
1047  * references.
1048  *
1049  * Returns: a new udev device, or #NULL if no matching parent exists.
1050  **/
1051 _public_ struct udev_device *udev_device_get_parent_with_subsystem_devtype(struct udev_device *udev_device, const char *subsystem, const char *devtype)
1052 {
1053         struct udev_device *parent;
1054
1055         if (subsystem == NULL) {
1056                 errno = EINVAL;
1057                 return NULL;
1058         }
1059
1060         parent = udev_device_get_parent(udev_device);
1061         while (parent != NULL) {
1062                 const char *parent_subsystem;
1063                 const char *parent_devtype;
1064
1065                 parent_subsystem = udev_device_get_subsystem(parent);
1066                 if (parent_subsystem != NULL && streq(parent_subsystem, subsystem)) {
1067                         if (devtype == NULL)
1068                                 break;
1069                         parent_devtype = udev_device_get_devtype(parent);
1070                         if (parent_devtype != NULL && streq(parent_devtype, devtype))
1071                                 break;
1072                 }
1073                 parent = udev_device_get_parent(parent);
1074         }
1075
1076         if (!parent)
1077                 errno = ENOENT;
1078
1079         return parent;
1080 }
1081
1082 /**
1083  * udev_device_get_udev:
1084  * @udev_device: udev device
1085  *
1086  * Retrieve the udev library context the device was created with.
1087  *
1088  * Returns: the udev library context
1089  **/
1090 _public_ struct udev *udev_device_get_udev(struct udev_device *udev_device)
1091 {
1092         if (udev_device == NULL)
1093                 return NULL;
1094         return udev_device->udev;
1095 }
1096
1097 /**
1098  * udev_device_ref:
1099  * @udev_device: udev device
1100  *
1101  * Take a reference of a udev device.
1102  *
1103  * Returns: the passed udev device
1104  **/
1105 _public_ struct udev_device *udev_device_ref(struct udev_device *udev_device)
1106 {
1107         if (udev_device == NULL)
1108                 return NULL;
1109         udev_device->refcount++;
1110         return udev_device;
1111 }
1112
1113 /**
1114  * udev_device_unref:
1115  * @udev_device: udev device
1116  *
1117  * Drop a reference of a udev device. If the refcount reaches zero,
1118  * the resources of the device will be released.
1119  *
1120  * Returns: #NULL
1121  **/
1122 _public_ struct udev_device *udev_device_unref(struct udev_device *udev_device)
1123 {
1124         if (udev_device == NULL)
1125                 return NULL;
1126         udev_device->refcount--;
1127         if (udev_device->refcount > 0)
1128                 return NULL;
1129         if (udev_device->parent_device != NULL)
1130                 udev_device_unref(udev_device->parent_device);
1131         free(udev_device->syspath);
1132         free(udev_device->sysname);
1133         free(udev_device->devnode);
1134         free(udev_device->subsystem);
1135         free(udev_device->devtype);
1136         udev_list_cleanup(&udev_device->devlinks_list);
1137         udev_list_cleanup(&udev_device->properties_list);
1138         udev_list_cleanup(&udev_device->sysattr_value_list);
1139         udev_list_cleanup(&udev_device->sysattr_list);
1140         udev_list_cleanup(&udev_device->tags_list);
1141         free(udev_device->action);
1142         free(udev_device->driver);
1143         free(udev_device->devpath_old);
1144         free(udev_device->id_filename);
1145         free(udev_device->envp);
1146         free(udev_device->monitor_buf);
1147         free(udev_device);
1148         return NULL;
1149 }
1150
1151 /**
1152  * udev_device_get_devpath:
1153  * @udev_device: udev device
1154  *
1155  * Retrieve the kernel devpath value of the udev device. The path
1156  * does not contain the sys mount point, and starts with a '/'.
1157  *
1158  * Returns: the devpath of the udev device
1159  **/
1160 _public_ const char *udev_device_get_devpath(struct udev_device *udev_device)
1161 {
1162         if (udev_device == NULL)
1163                 return NULL;
1164         return udev_device->devpath;
1165 }
1166
1167 /**
1168  * udev_device_get_syspath:
1169  * @udev_device: udev device
1170  *
1171  * Retrieve the sys path of the udev device. The path is an
1172  * absolute path and starts with the sys mount point.
1173  *
1174  * Returns: the sys path of the udev device
1175  **/
1176 _public_ const char *udev_device_get_syspath(struct udev_device *udev_device)
1177 {
1178         if (udev_device == NULL)
1179                 return NULL;
1180         return udev_device->syspath;
1181 }
1182
1183 /**
1184  * udev_device_get_sysname:
1185  * @udev_device: udev device
1186  *
1187  * Get the kernel device name in /sys.
1188  *
1189  * Returns: the name string of the device device
1190  **/
1191 _public_ const char *udev_device_get_sysname(struct udev_device *udev_device)
1192 {
1193         if (udev_device == NULL)
1194                 return NULL;
1195         return udev_device->sysname;
1196 }
1197
1198 /**
1199  * udev_device_get_sysnum:
1200  * @udev_device: udev device
1201  *
1202  * Get the instance number of the device.
1203  *
1204  * Returns: the trailing number string of the device name
1205  **/
1206 _public_ const char *udev_device_get_sysnum(struct udev_device *udev_device)
1207 {
1208         if (udev_device == NULL)
1209                 return NULL;
1210         return udev_device->sysnum;
1211 }
1212
1213 /**
1214  * udev_device_get_devnode:
1215  * @udev_device: udev device
1216  *
1217  * Retrieve the device node file name belonging to the udev device.
1218  * The path is an absolute path, and starts with the device directory.
1219  *
1220  * Returns: the device node file name of the udev device, or #NULL if no device node exists
1221  **/
1222 _public_ const char *udev_device_get_devnode(struct udev_device *udev_device)
1223 {
1224         if (udev_device == NULL)
1225                 return NULL;
1226         if (udev_device->devnode != NULL)
1227                 return udev_device->devnode;
1228         if (!udev_device->info_loaded)
1229                 udev_device_read_uevent_file(udev_device);
1230         return udev_device->devnode;
1231 }
1232
1233 /**
1234  * udev_device_get_devlinks_list_entry:
1235  * @udev_device: udev device
1236  *
1237  * Retrieve the list of device links pointing to the device file of
1238  * the udev device. The next list entry can be retrieved with
1239  * udev_list_entry_get_next(), which returns #NULL if no more entries exist.
1240  * The devlink path can be retrieved from the list entry by
1241  * udev_list_entry_get_name(). The path is an absolute path, and starts with
1242  * the device directory.
1243  *
1244  * Returns: the first entry of the device node link list
1245  **/
1246 _public_ struct udev_list_entry *udev_device_get_devlinks_list_entry(struct udev_device *udev_device)
1247 {
1248         if (udev_device == NULL)
1249                 return NULL;
1250         if (!udev_device->info_loaded)
1251                 udev_device_read_db(udev_device, NULL);
1252         return udev_list_get_entry(&udev_device->devlinks_list);
1253 }
1254
1255 void udev_device_cleanup_devlinks_list(struct udev_device *udev_device)
1256 {
1257         udev_device->devlinks_uptodate = false;
1258         udev_list_cleanup(&udev_device->devlinks_list);
1259 }
1260
1261 /**
1262  * udev_device_get_properties_list_entry:
1263  * @udev_device: udev device
1264  *
1265  * Retrieve the list of key/value device properties of the udev
1266  * device. The next list entry can be retrieved with udev_list_entry_get_next(),
1267  * which returns #NULL if no more entries exist. The property name
1268  * can be retrieved from the list entry by udev_list_entry_get_name(),
1269  * the property value by udev_list_entry_get_value().
1270  *
1271  * Returns: the first entry of the property list
1272  **/
1273 _public_ struct udev_list_entry *udev_device_get_properties_list_entry(struct udev_device *udev_device)
1274 {
1275         if (udev_device == NULL)
1276                 return NULL;
1277         if (!udev_device->info_loaded) {
1278                 udev_device_read_uevent_file(udev_device);
1279                 udev_device_read_db(udev_device, NULL);
1280         }
1281         if (!udev_device->devlinks_uptodate) {
1282                 char symlinks[UTIL_PATH_SIZE];
1283                 struct udev_list_entry *list_entry;
1284
1285                 udev_device->devlinks_uptodate = true;
1286                 list_entry = udev_device_get_devlinks_list_entry(udev_device);
1287                 if (list_entry != NULL) {
1288                         char *s;
1289                         size_t l;
1290
1291                         s = symlinks;
1292                         l = strpcpyl(&s, sizeof(symlinks), udev_list_entry_get_name(list_entry), NULL);
1293                         udev_list_entry_foreach(list_entry, udev_list_entry_get_next(list_entry))
1294                                 l = strpcpyl(&s, l, " ", udev_list_entry_get_name(list_entry), NULL);
1295                         udev_device_add_property(udev_device, "DEVLINKS", symlinks);
1296                 }
1297         }
1298         if (!udev_device->tags_uptodate) {
1299                 udev_device->tags_uptodate = true;
1300                 if (udev_device_get_tags_list_entry(udev_device) != NULL) {
1301                         char tags[UTIL_PATH_SIZE];
1302                         struct udev_list_entry *list_entry;
1303                         char *s;
1304                         size_t l;
1305
1306                         s = tags;
1307                         l = strpcpyl(&s, sizeof(tags), ":", NULL);
1308                         udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(udev_device))
1309                                 l = strpcpyl(&s, l, udev_list_entry_get_name(list_entry), ":", NULL);
1310                         udev_device_add_property(udev_device, "TAGS", tags);
1311                 }
1312         }
1313         return udev_list_get_entry(&udev_device->properties_list);
1314 }
1315
1316 /**
1317  * udev_device_get_action:
1318  * @udev_device: udev device
1319  *
1320  * This is only valid if the device was received through a monitor. Devices read from
1321  * sys do not have an action string. Usual actions are: add, remove, change, online,
1322  * offline.
1323  *
1324  * Returns: the kernel action value, or #NULL if there is no action value available.
1325  **/
1326 _public_ const char *udev_device_get_action(struct udev_device *udev_device)
1327 {
1328         if (udev_device == NULL)
1329                 return NULL;
1330         return udev_device->action;
1331 }
1332
1333 /**
1334  * udev_device_get_usec_since_initialized:
1335  * @udev_device: udev device
1336  *
1337  * Return the number of microseconds passed since udev set up the
1338  * device for the first time.
1339  *
1340  * This is only implemented for devices with need to store properties
1341  * in the udev database. All other devices return 0 here.
1342  *
1343  * Returns: the number of microseconds since the device was first seen.
1344  **/
1345 _public_ unsigned long long int udev_device_get_usec_since_initialized(struct udev_device *udev_device)
1346 {
1347         usec_t now_ts;
1348
1349         if (udev_device == NULL)
1350                 return 0;
1351         if (!udev_device->info_loaded)
1352                 udev_device_read_db(udev_device, NULL);
1353         if (udev_device->usec_initialized == 0)
1354                 return 0;
1355         now_ts = now(CLOCK_MONOTONIC);
1356         if (now_ts == 0)
1357                 return 0;
1358         return now_ts - udev_device->usec_initialized;
1359 }
1360
1361 usec_t udev_device_get_usec_initialized(struct udev_device *udev_device)
1362 {
1363         return udev_device->usec_initialized;
1364 }
1365
1366 void udev_device_set_usec_initialized(struct udev_device *udev_device, usec_t usec_initialized)
1367 {
1368         char num[32];
1369
1370         udev_device->usec_initialized = usec_initialized;
1371         snprintf(num, sizeof(num), USEC_FMT, usec_initialized);
1372         udev_device_add_property(udev_device, "USEC_INITIALIZED", num);
1373 }
1374
1375 /**
1376  * udev_device_get_sysattr_value:
1377  * @udev_device: udev device
1378  * @sysattr: attribute name
1379  *
1380  * The retrieved value is cached in the device. Repeated calls will return the same
1381  * value and not open the attribute again.
1382  *
1383  * Returns: the content of a sys attribute file, or #NULL if there is no sys attribute value.
1384  **/
1385 _public_ const char *udev_device_get_sysattr_value(struct udev_device *udev_device, const char *sysattr)
1386 {
1387         struct udev_list_entry *list_entry;
1388         char path[UTIL_PATH_SIZE];
1389         char value[4096];
1390         struct stat statbuf;
1391         int fd;
1392         ssize_t size;
1393         const char *val = NULL;
1394
1395         if (udev_device == NULL)
1396                 return NULL;
1397         if (sysattr == NULL)
1398                 return NULL;
1399
1400         /* look for possibly already cached result */
1401         list_entry = udev_list_get_entry(&udev_device->sysattr_value_list);
1402         list_entry = udev_list_entry_get_by_name(list_entry, sysattr);
1403         if (list_entry != NULL)
1404                 return udev_list_entry_get_value(list_entry);
1405
1406         strscpyl(path, sizeof(path), udev_device_get_syspath(udev_device), "/", sysattr, NULL);
1407         if (lstat(path, &statbuf) != 0) {
1408                 udev_list_entry_add(&udev_device->sysattr_value_list, sysattr, NULL);
1409                 goto out;
1410         }
1411
1412         if (S_ISLNK(statbuf.st_mode)) {
1413                 /*
1414                  * Some core links return only the last element of the target path,
1415                  * these are just values, the paths should not be exposed.
1416                  */
1417                 if (streq(sysattr, "driver") ||
1418                     streq(sysattr, "subsystem") ||
1419                     streq(sysattr, "module")) {
1420                         if (util_get_sys_core_link_value(udev_device->udev, sysattr,
1421                                                          udev_device->syspath, value, sizeof(value)) < 0)
1422                                 return NULL;
1423                         list_entry = udev_list_entry_add(&udev_device->sysattr_value_list, sysattr, value);
1424                         val = udev_list_entry_get_value(list_entry);
1425                         goto out;
1426                 }
1427
1428                 goto out;
1429         }
1430
1431         /* skip directories */
1432         if (S_ISDIR(statbuf.st_mode))
1433                 goto out;
1434
1435         /* skip non-readable files */
1436         if ((statbuf.st_mode & S_IRUSR) == 0)
1437                 goto out;
1438
1439         /* read attribute value */
1440         fd = open(path, O_RDONLY|O_CLOEXEC);
1441         if (fd < 0)
1442                 goto out;
1443         size = read(fd, value, sizeof(value));
1444         close(fd);
1445         if (size < 0)
1446                 goto out;
1447         if (size == sizeof(value))
1448                 goto out;
1449
1450         /* got a valid value, store it in cache and return it */
1451         value[size] = '\0';
1452         util_remove_trailing_chars(value, '\n');
1453         list_entry = udev_list_entry_add(&udev_device->sysattr_value_list, sysattr, value);
1454         val = udev_list_entry_get_value(list_entry);
1455 out:
1456         return val;
1457 }
1458
1459 /**
1460  * udev_device_set_sysattr_value:
1461  * @udev_device: udev device
1462  * @sysattr: attribute name
1463  * @value: new value to be set
1464  *
1465  * Update the contents of the sys attribute and the cached value of the device.
1466  *
1467  * Returns: Negative error code on failure or 0 on success.
1468  **/
1469 _public_ int udev_device_set_sysattr_value(struct udev_device *udev_device, const char *sysattr, char *value)
1470 {
1471         struct udev_device *dev;
1472         char path[UTIL_PATH_SIZE];
1473         struct stat statbuf;
1474         int fd;
1475         ssize_t size, value_len;
1476         int ret = 0;
1477
1478         if (udev_device == NULL)
1479                 return -EINVAL;
1480         dev = udev_device;
1481         if (sysattr == NULL)
1482                 return -EINVAL;
1483         if (value == NULL)
1484                 value_len = 0;
1485         else
1486                 value_len = strlen(value);
1487
1488         strscpyl(path, sizeof(path), udev_device_get_syspath(dev), "/", sysattr, NULL);
1489         if (lstat(path, &statbuf) != 0) {
1490                 udev_list_entry_add(&dev->sysattr_value_list, sysattr, NULL);
1491                 ret = -ENXIO;
1492                 goto out;
1493         }
1494
1495         if (S_ISLNK(statbuf.st_mode)) {
1496                 ret = -EINVAL;
1497                 goto out;
1498         }
1499
1500         /* skip directories */
1501         if (S_ISDIR(statbuf.st_mode)) {
1502                 ret = -EISDIR;
1503                 goto out;
1504         }
1505
1506         /* skip non-readable files */
1507         if ((statbuf.st_mode & S_IRUSR) == 0) {
1508                 ret = -EACCES;
1509                 goto out;
1510         }
1511
1512         /* Value is limited to 4k */
1513         if (value_len > 4096) {
1514                 ret = -EINVAL;
1515                 goto out;
1516         }
1517         util_remove_trailing_chars(value, '\n');
1518
1519         /* write attribute value */
1520         fd = open(path, O_WRONLY|O_CLOEXEC);
1521         if (fd < 0) {
1522                 ret = -errno;
1523                 goto out;
1524         }
1525         size = write(fd, value, value_len);
1526         close(fd);
1527         if (size < 0) {
1528                 ret = -errno;
1529                 goto out;
1530         }
1531         if (size < value_len) {
1532                 ret = -EIO;
1533                 goto out;
1534         }
1535
1536         /* wrote a valid value, store it in cache and return it */
1537         udev_list_entry_add(&dev->sysattr_value_list, sysattr, value);
1538 out:
1539         if (dev != udev_device)
1540                 udev_device_unref(dev);
1541         return ret;
1542 }
1543
1544 static int udev_device_sysattr_list_read(struct udev_device *udev_device)
1545 {
1546         struct dirent *dent;
1547         DIR *dir;
1548         int num = 0;
1549
1550         if (udev_device == NULL)
1551                 return -EINVAL;
1552         if (udev_device->sysattr_list_read)
1553                 return 0;
1554
1555         dir = opendir(udev_device_get_syspath(udev_device));
1556         if (!dir)
1557                 return -errno;
1558
1559         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
1560                 char path[UTIL_PATH_SIZE];
1561                 struct stat statbuf;
1562
1563                 /* only handle symlinks and regular files */
1564                 if (dent->d_type != DT_LNK && dent->d_type != DT_REG)
1565                         continue;
1566
1567                 strscpyl(path, sizeof(path), udev_device_get_syspath(udev_device), "/", dent->d_name, NULL);
1568                 if (lstat(path, &statbuf) != 0)
1569                         continue;
1570                 if ((statbuf.st_mode & S_IRUSR) == 0)
1571                         continue;
1572
1573                 udev_list_entry_add(&udev_device->sysattr_list, dent->d_name, NULL);
1574                 num++;
1575         }
1576
1577         closedir(dir);
1578         udev_device->sysattr_list_read = true;
1579
1580         return num;
1581 }
1582
1583 /**
1584  * udev_device_get_sysattr_list_entry:
1585  * @udev_device: udev device
1586  *
1587  * Retrieve the list of available sysattrs, with value being empty;
1588  * This just return all available sysfs attributes for a particular
1589  * device without reading their values.
1590  *
1591  * Returns: the first entry of the property list
1592  **/
1593 _public_ struct udev_list_entry *udev_device_get_sysattr_list_entry(struct udev_device *udev_device)
1594 {
1595         if (!udev_device->sysattr_list_read) {
1596                 int ret;
1597                 ret = udev_device_sysattr_list_read(udev_device);
1598                 if (0 > ret)
1599                         return NULL;
1600         }
1601
1602         return udev_list_get_entry(&udev_device->sysattr_list);
1603 }
1604
1605 int udev_device_set_syspath(struct udev_device *udev_device, const char *syspath)
1606 {
1607         const char *pos;
1608         size_t len;
1609
1610         free(udev_device->syspath);
1611         udev_device->syspath = strdup(syspath);
1612         if (udev_device->syspath ==  NULL)
1613                 return -ENOMEM;
1614         udev_device->devpath = udev_device->syspath + strlen("/sys");
1615         udev_device_add_property(udev_device, "DEVPATH", udev_device->devpath);
1616
1617         pos = strrchr(udev_device->syspath, '/');
1618         if (pos == NULL)
1619                 return -EINVAL;
1620         udev_device->sysname = strdup(&pos[1]);
1621         if (udev_device->sysname == NULL)
1622                 return -ENOMEM;
1623
1624         /* some devices have '!' in their name, change that to '/' */
1625         len = 0;
1626         while (udev_device->sysname[len] != '\0') {
1627                 if (udev_device->sysname[len] == '!')
1628                         udev_device->sysname[len] = '/';
1629                 len++;
1630         }
1631
1632         /* trailing number */
1633         while (len > 0 && isdigit(udev_device->sysname[--len]))
1634                 udev_device->sysnum = &udev_device->sysname[len];
1635
1636         /* sysname is completely numeric */
1637         if (len == 0)
1638                 udev_device->sysnum = NULL;
1639
1640         return 0;
1641 }
1642
1643 static int udev_device_set_devnode(struct udev_device *udev_device, const char *devnode)
1644 {
1645         free(udev_device->devnode);
1646         if (devnode[0] != '/') {
1647                 if (asprintf(&udev_device->devnode, "/dev/%s", devnode) < 0)
1648                         udev_device->devnode = NULL;
1649         } else {
1650                 udev_device->devnode = strdup(devnode);
1651         }
1652         if (udev_device->devnode == NULL)
1653                 return -ENOMEM;
1654         udev_device_add_property(udev_device, "DEVNAME", udev_device->devnode);
1655         return 0;
1656 }
1657
1658 int udev_device_add_devlink(struct udev_device *udev_device, const char *devlink)
1659 {
1660         struct udev_list_entry *list_entry;
1661
1662         udev_device->devlinks_uptodate = false;
1663         list_entry = udev_list_entry_add(&udev_device->devlinks_list, devlink, NULL);
1664         if (list_entry == NULL)
1665                 return -ENOMEM;
1666         return 0;
1667 }
1668
1669 const char *udev_device_get_id_filename(struct udev_device *udev_device)
1670 {
1671         if (udev_device->id_filename == NULL) {
1672                 if (udev_device_get_subsystem(udev_device) == NULL)
1673                         return NULL;
1674
1675                 if (major(udev_device_get_devnum(udev_device)) > 0) {
1676                         /* use dev_t -- b259:131072, c254:0 */
1677                         if (asprintf(&udev_device->id_filename, "%c%u:%u",
1678                                      streq(udev_device_get_subsystem(udev_device), "block") ? 'b' : 'c',
1679                                      major(udev_device_get_devnum(udev_device)),
1680                                      minor(udev_device_get_devnum(udev_device))) < 0)
1681                                 udev_device->id_filename = NULL;
1682                 } else if (udev_device_get_ifindex(udev_device) > 0) {
1683                         /* use netdev ifindex -- n3 */
1684                         if (asprintf(&udev_device->id_filename, "n%u", udev_device_get_ifindex(udev_device)) < 0)
1685                                 udev_device->id_filename = NULL;
1686                 } else {
1687                         /*
1688                          * use $subsys:$syname -- pci:0000:00:1f.2
1689                          * sysname() has '!' translated, get it from devpath
1690                          */
1691                         const char *sysname;
1692                         sysname = strrchr(udev_device->devpath, '/');
1693                         if (sysname == NULL)
1694                                 return NULL;
1695                         sysname = &sysname[1];
1696                         if (asprintf(&udev_device->id_filename, "+%s:%s", udev_device_get_subsystem(udev_device), sysname) < 0)
1697                                 udev_device->id_filename = NULL;
1698                 }
1699         }
1700         return udev_device->id_filename;
1701 }
1702
1703 /**
1704  * udev_device_get_is_initialized:
1705  * @udev_device: udev device
1706  *
1707  * Check if udev has already handled the device and has set up
1708  * device node permissions and context, or has renamed a network
1709  * device.
1710  *
1711  * This is only implemented for devices with a device node
1712  * or network interfaces. All other devices return 1 here.
1713  *
1714  * Returns: 1 if the device is set up. 0 otherwise.
1715  **/
1716 _public_ int udev_device_get_is_initialized(struct udev_device *udev_device)
1717 {
1718         if (!udev_device->info_loaded)
1719                 udev_device_read_db(udev_device, NULL);
1720         return udev_device->is_initialized;
1721 }
1722
1723 void udev_device_set_is_initialized(struct udev_device *udev_device)
1724 {
1725         udev_device->is_initialized = true;
1726 }
1727
1728 static bool is_valid_tag(const char *tag)
1729 {
1730         return !strchr(tag, ':') && !strchr(tag, ' ');
1731 }
1732
1733 int udev_device_add_tag(struct udev_device *udev_device, const char *tag)
1734 {
1735         if (!is_valid_tag(tag))
1736                 return -EINVAL;
1737         udev_device->tags_uptodate = false;
1738         if (udev_list_entry_add(&udev_device->tags_list, tag, NULL) != NULL)
1739                 return 0;
1740         return -ENOMEM;
1741 }
1742
1743 void udev_device_remove_tag(struct udev_device *udev_device, const char *tag)
1744 {
1745         struct udev_list_entry *e;
1746
1747         if (!is_valid_tag(tag))
1748                 return;
1749         e = udev_list_get_entry(&udev_device->tags_list);
1750         e = udev_list_entry_get_by_name(e, tag);
1751         if (e) {
1752                 udev_device->tags_uptodate = false;
1753                 udev_list_entry_delete(e);
1754         }
1755 }
1756
1757 void udev_device_cleanup_tags_list(struct udev_device *udev_device)
1758 {
1759         udev_device->tags_uptodate = false;
1760         udev_list_cleanup(&udev_device->tags_list);
1761 }
1762
1763 /**
1764  * udev_device_get_tags_list_entry:
1765  * @udev_device: udev device
1766  *
1767  * Retrieve the list of tags attached to the udev device. The next
1768  * list entry can be retrieved with udev_list_entry_get_next(),
1769  * which returns #NULL if no more entries exist. The tag string
1770  * can be retrieved from the list entry by udev_list_entry_get_name().
1771  *
1772  * Returns: the first entry of the tag list
1773  **/
1774 _public_ struct udev_list_entry *udev_device_get_tags_list_entry(struct udev_device *udev_device)
1775 {
1776         if (udev_device == NULL)
1777                 return NULL;
1778         if (!udev_device->info_loaded)
1779                 udev_device_read_db(udev_device, NULL);
1780         return udev_list_get_entry(&udev_device->tags_list);
1781 }
1782
1783 /**
1784  * udev_device_has_tag:
1785  * @udev_device: udev device
1786  * @tag: tag name
1787  *
1788  * Check if a given device has a certain tag associated.
1789  *
1790  * Returns: 1 if the tag is found. 0 otherwise.
1791  **/
1792 _public_ int udev_device_has_tag(struct udev_device *udev_device, const char *tag)
1793 {
1794         struct udev_list_entry *list_entry;
1795
1796         if (udev_device == NULL)
1797                 return false;
1798         if (!udev_device->info_loaded)
1799                 udev_device_read_db(udev_device, NULL);
1800         list_entry = udev_device_get_tags_list_entry(udev_device);
1801         if (udev_list_entry_get_by_name(list_entry, tag) != NULL)
1802                 return true;
1803         return false;
1804 }
1805
1806 #define ENVP_SIZE                        128
1807 #define MONITOR_BUF_SIZE                4096
1808 static int update_envp_monitor_buf(struct udev_device *udev_device)
1809 {
1810         struct udev_list_entry *list_entry;
1811         char *s;
1812         size_t l;
1813         unsigned int i;
1814
1815         /* monitor buffer of property strings */
1816         free(udev_device->monitor_buf);
1817         udev_device->monitor_buf_len = 0;
1818         udev_device->monitor_buf = malloc(MONITOR_BUF_SIZE);
1819         if (udev_device->monitor_buf == NULL)
1820                 return -ENOMEM;
1821
1822         /* envp array, strings will point into monitor buffer */
1823         if (udev_device->envp == NULL)
1824                 udev_device->envp = malloc(sizeof(char *) * ENVP_SIZE);
1825         if (udev_device->envp == NULL)
1826                 return -ENOMEM;
1827
1828         i = 0;
1829         s = udev_device->monitor_buf;
1830         l = MONITOR_BUF_SIZE;
1831         udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device)) {
1832                 const char *key;
1833
1834                 key = udev_list_entry_get_name(list_entry);
1835                 /* skip private variables */
1836                 if (key[0] == '.')
1837                         continue;
1838
1839                 /* add string to envp array */
1840                 udev_device->envp[i++] = s;
1841                 if (i+1 >= ENVP_SIZE)
1842                         return -EINVAL;
1843
1844                 /* add property string to monitor buffer */
1845                 l = strpcpyl(&s, l, key, "=", udev_list_entry_get_value(list_entry), NULL);
1846                 if (l == 0)
1847                         return -EINVAL;
1848                 /* advance past the trailing '\0' that strpcpyl() guarantees */
1849                 s++;
1850                 l--;
1851         }
1852         udev_device->envp[i] = NULL;
1853         udev_device->monitor_buf_len = s - udev_device->monitor_buf;
1854         udev_device->envp_uptodate = true;
1855         return 0;
1856 }
1857
1858 char **udev_device_get_properties_envp(struct udev_device *udev_device)
1859 {
1860         if (!udev_device->envp_uptodate)
1861                 if (update_envp_monitor_buf(udev_device) != 0)
1862                         return NULL;
1863         return udev_device->envp;
1864 }
1865
1866 ssize_t udev_device_get_properties_monitor_buf(struct udev_device *udev_device, const char **buf)
1867 {
1868         if (!udev_device->envp_uptodate)
1869                 if (update_envp_monitor_buf(udev_device) != 0)
1870                         return -EINVAL;
1871         *buf = udev_device->monitor_buf;
1872         return udev_device->monitor_buf_len;
1873 }
1874
1875 int udev_device_set_action(struct udev_device *udev_device, const char *action)
1876 {
1877         free(udev_device->action);
1878         udev_device->action = strdup(action);
1879         if (udev_device->action == NULL)
1880                 return -ENOMEM;
1881         udev_device_add_property(udev_device, "ACTION", udev_device->action);
1882         return 0;
1883 }
1884
1885 int udev_device_get_devlink_priority(struct udev_device *udev_device)
1886 {
1887         if (!udev_device->info_loaded)
1888                 udev_device_read_db(udev_device, NULL);
1889         return udev_device->devlink_priority;
1890 }
1891
1892 int udev_device_set_devlink_priority(struct udev_device *udev_device, int prio)
1893 {
1894          udev_device->devlink_priority = prio;
1895         return 0;
1896 }
1897
1898 int udev_device_get_watch_handle(struct udev_device *udev_device)
1899 {
1900         if (!udev_device->info_loaded)
1901                 udev_device_read_db(udev_device, NULL);
1902         return udev_device->watch_handle;
1903 }
1904
1905 int udev_device_set_watch_handle(struct udev_device *udev_device, int handle)
1906 {
1907         udev_device->watch_handle = handle;
1908         return 0;
1909 }
1910
1911 bool udev_device_get_db_persist(struct udev_device *udev_device)
1912 {
1913         return udev_device->db_persist;
1914 }
1915
1916 void udev_device_set_db_persist(struct udev_device *udev_device)
1917 {
1918         udev_device->db_persist = true;
1919 }