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), "%d", 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)
 727                         return NULL;
 728
 729                 if (!S_ISDIR(statbuf.st_mode)) {
 730                         errno = EISDIR;
 731                         return NULL;
 732                 }
 733         }
 734
 735         udev_device = udev_device_new(udev);
 736         if (udev_device == NULL)
 737                 return NULL;
 738
 739         udev_device_set_syspath(udev_device, path);
 740         log_debug("device %p has devpath '%s'", udev_device, udev_device_get_devpath(udev_device));
 741
 742         return udev_device;
 743 }
 744
 745 /**
 746  * udev_device_new_from_devnum:
 747  * @udev: udev library context
 748  * @type: char or block device
 749  * @devnum: device major/minor number
 750  *
 751  * Create new udev device, and fill in information from the sys
 752  * device and the udev database entry. The device is looked-up
 753  * by its major/minor number and type. Character and block device
 754  * numbers are not unique across the two types.
 755  *
 756  * The initial refcount is 1, and needs to be decremented to
 757  * release the resources of the udev device.
 758  *
 759  * Returns: a new udev device, or #NULL, if it does not exist
 760  **/
 761 _public_ struct udev_device *udev_device_new_from_devnum(struct udev *udev, char type, dev_t devnum)
 762 {
 763         char path[UTIL_PATH_SIZE];
 764         const char *type_str;
 765
 766         if (type == 'b')
 767                 type_str = "block";
 768         else if (type == 'c')
 769                 type_str = "char";
 770         else {
 771                 errno = EINVAL;
 772                 return NULL;
 773         }
 774
 775         /* use /sys/dev/{block,char}/<maj>:<min> link */
 776         snprintf(path, sizeof(path), "/sys/dev/%s/%u:%u",
 777                  type_str, major(devnum), minor(devnum));
 778         return udev_device_new_from_syspath(udev, path);
 779 }
 780
 781 /**
 782  * udev_device_new_from_device_id:
 783  * @udev: udev library context
 784  * @id: text string identifying a kernel device
 785  *
 786  * Create new udev device, and fill in information from the sys
 787  * device and the udev database entry. The device is looked-up
 788  * by a special string:
 789  *   b8:2          - block device major:minor
 790  *   c128:1        - char device major:minor
 791  *   n3            - network device ifindex
 792  *   +sound:card29 - kernel driver core subsystem:device name
 793  *
 794  * The initial refcount is 1, and needs to be decremented to
 795  * release the resources of the udev device.
 796  *
 797  * Returns: a new udev device, or #NULL, if it does not exist
 798  **/
 799 _public_ struct udev_device *udev_device_new_from_device_id(struct udev *udev, const char *id)
 800 {
 801         char type;
 802         int maj, min;
 803         char subsys[UTIL_PATH_SIZE];
 804         char *sysname;
 805
 806         switch(id[0]) {
 807         case 'b':
 808         case 'c':
 809                 if (sscanf(id, "%c%i:%i", &type, &maj, &min) != 3)
 810                         return NULL;
 811                 return udev_device_new_from_devnum(udev, type, makedev(maj, min));
 812         case 'n': {
 813                 int sk;
 814                 struct ifreq ifr;
 815                 struct udev_device *dev;
 816                 int ifindex;
 817
 818                 ifindex = strtoul(&id[1], NULL, 10);
 819                 if (ifindex <= 0) {
 820                         errno = EINVAL;
 821                         return NULL;
 822                 }
 823
 824                 sk = socket(PF_INET, SOCK_DGRAM, 0);
 825                 if (sk < 0)
 826                         return NULL;
 827                 memzero(&ifr, sizeof(struct ifreq));
 828                 ifr.ifr_ifindex = ifindex;
 829                 if (ioctl(sk, SIOCGIFNAME, &ifr) != 0) {
 830                         close(sk);
 831                         return NULL;
 832                 }
 833                 close(sk);
 834
 835                 dev = udev_device_new_from_subsystem_sysname(udev, "net", ifr.ifr_name);
 836                 if (dev == NULL)
 837                         return NULL;
 838                 if (udev_device_get_ifindex(dev) == ifindex)
 839                         return dev;
 840
 841                 /* this is racy, so we may end up with the wrong device */
 842                 udev_device_unref(dev);
 843                 errno = ENODEV;
 844                 return NULL;
 845         }
 846         case '+':
 847                 strscpy(subsys, sizeof(subsys), &id[1]);
 848                 sysname = strchr(subsys, ':');
 849                 if (sysname == NULL) {
 850                         errno = EINVAL;
 851                         return NULL;
 852                 }
 853                 sysname[0] = '\0';
 854                 sysname = &sysname[1];
 855                 return udev_device_new_from_subsystem_sysname(udev, subsys, sysname);
 856         default:
 857                 errno = EINVAL;
 858                 return NULL;
 859         }
 860 }
 861
 862 /**
 863  * udev_device_new_from_subsystem_sysname:
 864  * @udev: udev library context
 865  * @subsystem: the subsystem of the device
 866  * @sysname: the name of the device
 867  *
 868  * Create new udev device, and fill in information from the sys device
 869  * and the udev database entry. The device is looked up by the subsystem
 870  * and name string of the device, like "mem" / "zero", or "block" / "sda".
 871  *
 872  * The initial refcount is 1, and needs to be decremented to
 873  * release the resources of the udev device.
 874  *
 875  * Returns: a new udev device, or #NULL, if it does not exist
 876  **/
 877 _public_ struct udev_device *udev_device_new_from_subsystem_sysname(struct udev *udev, const char *subsystem, const char *sysname)
 878 {
 879         char path[UTIL_PATH_SIZE];
 880         struct stat statbuf;
 881
 882         if (streq(subsystem, "subsystem")) {
 883                 strscpyl(path, sizeof(path), "/sys/subsystem/", sysname, NULL);
 884                 if (stat(path, &statbuf) == 0)
 885                         goto found;
 886
 887                 strscpyl(path, sizeof(path), "/sys/bus/", sysname, NULL);
 888                 if (stat(path, &statbuf) == 0)
 889                         goto found;
 890
 891                 strscpyl(path, sizeof(path), "/sys/class/", sysname, NULL);
 892                 if (stat(path, &statbuf) == 0)
 893                         goto found;
 894                 goto out;
 895         }
 896
 897         if (streq(subsystem, "module")) {
 898                 strscpyl(path, sizeof(path), "/sys/module/", sysname, NULL);
 899                 if (stat(path, &statbuf) == 0)
 900                         goto found;
 901                 goto out;
 902         }
 903
 904         if (streq(subsystem, "drivers")) {
 905                 char subsys[UTIL_NAME_SIZE];
 906                 char *driver;
 907
 908                 strscpy(subsys, sizeof(subsys), sysname);
 909                 driver = strchr(subsys, ':');
 910                 if (driver != NULL) {
 911                         driver[0] = '\0';
 912                         driver = &driver[1];
 913
 914                         strscpyl(path, sizeof(path), "/sys/subsystem/", subsys, "/drivers/", driver, NULL);
 915                         if (stat(path, &statbuf) == 0)
 916                                 goto found;
 917
 918                         strscpyl(path, sizeof(path), "/sys/bus/", subsys, "/drivers/", driver, NULL);
 919                         if (stat(path, &statbuf) == 0)
 920                                 goto found;
 921                 } else
 922                         errno = EINVAL;
 923
 924                 goto out;
 925         }
 926
 927         strscpyl(path, sizeof(path), "/sys/subsystem/", subsystem, "/devices/", sysname, NULL);
 928         if (stat(path, &statbuf) == 0)
 929                 goto found;
 930
 931         strscpyl(path, sizeof(path), "/sys/bus/", subsystem, "/devices/", sysname, NULL);
 932         if (stat(path, &statbuf) == 0)
 933                 goto found;
 934
 935         strscpyl(path, sizeof(path), "/sys/class/", subsystem, "/", sysname, NULL);
 936         if (stat(path, &statbuf) == 0)
 937                 goto found;
 938 out:
 939         return NULL;
 940 found:
 941         return udev_device_new_from_syspath(udev, path);
 942 }
 943
 944 /**
 945  * udev_device_new_from_environment
 946  * @udev: udev library context
 947  *
 948  * Create new udev device, and fill in information from the
 949  * current process environment. This only works reliable if
 950  * the process is called from a udev rule. It is usually used
 951  * for tools executed from IMPORT= rules.
 952  *
 953  * The initial refcount is 1, and needs to be decremented to
 954  * release the resources of the udev device.
 955  *
 956  * Returns: a new udev device, or #NULL, if it does not exist
 957  **/
 958 _public_ struct udev_device *udev_device_new_from_environment(struct udev *udev)
 959 {
 960         int i;
 961         struct udev_device *udev_device;
 962
 963         udev_device = udev_device_new(udev);
 964         if (udev_device == NULL)
 965                 return NULL;
 966         udev_device_set_info_loaded(udev_device);
 967
 968         for (i = 0; environ[i] != NULL; i++)
 969                 udev_device_add_property_from_string_parse(udev_device, environ[i]);
 970
 971         if (udev_device_add_property_from_string_parse_finish(udev_device) < 0) {
 972                 log_debug("missing values, invalid device");
 973                 udev_device_unref(udev_device);
 974                 udev_device = NULL;
 975         }
 976
 977         return udev_device;
 978 }
 979
 980 static struct udev_device *device_new_from_parent(struct udev_device *udev_device)
 981 {
 982         struct udev_device *udev_device_parent = NULL;
 983         char path[UTIL_PATH_SIZE];
 984         const char *subdir;
 985
 986         strscpy(path, sizeof(path), udev_device->syspath);
 987         subdir = path + strlen("/sys/");
 988         for (;;) {
 989                 char *pos;
 990
 991                 pos = strrchr(subdir, '/');
 992                 if (pos == NULL || pos < &subdir[2])
 993                         break;
 994                 pos[0] = '\0';
 995                 udev_device_parent = udev_device_new_from_syspath(udev_device->udev, path);
 996                 if (udev_device_parent != NULL)
 997                         return udev_device_parent;
 998         }
 999
1000         errno = ENOENT;
1001         return NULL;
1002 }
1003
1004 /**
1005  * udev_device_get_parent:
1006  * @udev_device: the device to start searching from
1007  *
1008  * Find the next parent device, and fill in information from the sys
1009  * device and the udev database entry.
1010  *
1011  * Returned device is not referenced. It is attached to the child
1012  * device, and will be cleaned up when the child device is cleaned up.
1013  *
1014  * It is not necessarily just the upper level directory, empty or not
1015  * recognized sys directories are ignored.
1016  *
1017  * It can be called as many times as needed, without caring about
1018  * references.
1019  *
1020  * Returns: a new udev device, or #NULL, if it no parent exist.
1021  **/
1022 _public_ struct udev_device *udev_device_get_parent(struct udev_device *udev_device)
1023 {
1024         if (udev_device == NULL) {
1025                 errno = EINVAL;
1026                 return NULL;
1027         }
1028         if (!udev_device->parent_set) {
1029                 udev_device->parent_set = true;
1030                 udev_device->parent_device = device_new_from_parent(udev_device);
1031         }
1032         return udev_device->parent_device;
1033 }
1034
1035 /**
1036  * udev_device_get_parent_with_subsystem_devtype:
1037  * @udev_device: udev device to start searching from
1038  * @subsystem: the subsystem of the device
1039  * @devtype: the type (DEVTYPE) of the device
1040  *
1041  * Find the next parent device, with a matching subsystem and devtype
1042  * value, and fill in information from the sys device and the udev
1043  * database entry.
1044  *
1045  * If devtype is #NULL, only subsystem is checked, and any devtype will
1046  * match.
1047  *
1048  * Returned device is not referenced. It is attached to the child
1049  * device, and will be cleaned up when the child device is cleaned up.
1050  *
1051  * It can be called as many times as needed, without caring about
1052  * references.
1053  *
1054  * Returns: a new udev device, or #NULL if no matching parent exists.
1055  **/
1056 _public_ struct udev_device *udev_device_get_parent_with_subsystem_devtype(struct udev_device *udev_device, const char *subsystem, const char *devtype)
1057 {
1058         struct udev_device *parent;
1059
1060         if (subsystem == NULL) {
1061                 errno = EINVAL;
1062                 return NULL;
1063         }
1064
1065         parent = udev_device_get_parent(udev_device);
1066         while (parent != NULL) {
1067                 const char *parent_subsystem;
1068                 const char *parent_devtype;
1069
1070                 parent_subsystem = udev_device_get_subsystem(parent);
1071                 if (parent_subsystem != NULL && streq(parent_subsystem, subsystem)) {
1072                         if (devtype == NULL)
1073                                 break;
1074                         parent_devtype = udev_device_get_devtype(parent);
1075                         if (parent_devtype != NULL && streq(parent_devtype, devtype))
1076                                 break;
1077                 }
1078                 parent = udev_device_get_parent(parent);
1079         }
1080
1081         if (!parent)
1082                 errno = ENOENT;
1083
1084         return parent;
1085 }
1086
1087 /**
1088  * udev_device_get_udev:
1089  * @udev_device: udev device
1090  *
1091  * Retrieve the udev library context the device was created with.
1092  *
1093  * Returns: the udev library context
1094  **/
1095 _public_ struct udev *udev_device_get_udev(struct udev_device *udev_device)
1096 {
1097         if (udev_device == NULL)
1098                 return NULL;
1099         return udev_device->udev;
1100 }
1101
1102 /**
1103  * udev_device_ref:
1104  * @udev_device: udev device
1105  *
1106  * Take a reference of a udev device.
1107  *
1108  * Returns: the passed udev device
1109  **/
1110 _public_ struct udev_device *udev_device_ref(struct udev_device *udev_device)
1111 {
1112         if (udev_device == NULL)
1113                 return NULL;
1114         udev_device->refcount++;
1115         return udev_device;
1116 }
1117
1118 /**
1119  * udev_device_unref:
1120  * @udev_device: udev device
1121  *
1122  * Drop a reference of a udev device. If the refcount reaches zero,
1123  * the resources of the device will be released.
1124  *
1125  * Returns: #NULL
1126  **/
1127 _public_ struct udev_device *udev_device_unref(struct udev_device *udev_device)
1128 {
1129         if (udev_device == NULL)
1130                 return NULL;
1131         udev_device->refcount--;
1132         if (udev_device->refcount > 0)
1133                 return NULL;
1134         if (udev_device->parent_device != NULL)
1135                 udev_device_unref(udev_device->parent_device);
1136         free(udev_device->syspath);
1137         free(udev_device->sysname);
1138         free(udev_device->devnode);
1139         free(udev_device->subsystem);
1140         free(udev_device->devtype);
1141         udev_list_cleanup(&udev_device->devlinks_list);
1142         udev_list_cleanup(&udev_device->properties_list);
1143         udev_list_cleanup(&udev_device->sysattr_value_list);
1144         udev_list_cleanup(&udev_device->sysattr_list);
1145         udev_list_cleanup(&udev_device->tags_list);
1146         free(udev_device->action);
1147         free(udev_device->driver);
1148         free(udev_device->devpath_old);
1149         free(udev_device->id_filename);
1150         free(udev_device->envp);
1151         free(udev_device->monitor_buf);
1152         free(udev_device);
1153         return NULL;
1154 }
1155
1156 /**
1157  * udev_device_get_devpath:
1158  * @udev_device: udev device
1159  *
1160  * Retrieve the kernel devpath value of the udev device. The path
1161  * does not contain the sys mount point, and starts with a '/'.
1162  *
1163  * Returns: the devpath of the udev device
1164  **/
1165 _public_ const char *udev_device_get_devpath(struct udev_device *udev_device)
1166 {
1167         if (udev_device == NULL)
1168                 return NULL;
1169         return udev_device->devpath;
1170 }
1171
1172 /**
1173  * udev_device_get_syspath:
1174  * @udev_device: udev device
1175  *
1176  * Retrieve the sys path of the udev device. The path is an
1177  * absolute path and starts with the sys mount point.
1178  *
1179  * Returns: the sys path of the udev device
1180  **/
1181 _public_ const char *udev_device_get_syspath(struct udev_device *udev_device)
1182 {
1183         if (udev_device == NULL)
1184                 return NULL;
1185         return udev_device->syspath;
1186 }
1187
1188 /**
1189  * udev_device_get_sysname:
1190  * @udev_device: udev device
1191  *
1192  * Get the kernel device name in /sys.
1193  *
1194  * Returns: the name string of the device device
1195  **/
1196 _public_ const char *udev_device_get_sysname(struct udev_device *udev_device)
1197 {
1198         if (udev_device == NULL)
1199                 return NULL;
1200         return udev_device->sysname;
1201 }
1202
1203 /**
1204  * udev_device_get_sysnum:
1205  * @udev_device: udev device
1206  *
1207  * Get the instance number of the device.
1208  *
1209  * Returns: the trailing number string of the device name
1210  **/
1211 _public_ const char *udev_device_get_sysnum(struct udev_device *udev_device)
1212 {
1213         if (udev_device == NULL)
1214                 return NULL;
1215         return udev_device->sysnum;
1216 }
1217
1218 /**
1219  * udev_device_get_devnode:
1220  * @udev_device: udev device
1221  *
1222  * Retrieve the device node file name belonging to the udev device.
1223  * The path is an absolute path, and starts with the device directory.
1224  *
1225  * Returns: the device node file name of the udev device, or #NULL if no device node exists
1226  **/
1227 _public_ const char *udev_device_get_devnode(struct udev_device *udev_device)
1228 {
1229         if (udev_device == NULL)
1230                 return NULL;
1231         if (udev_device->devnode != NULL)
1232                 return udev_device->devnode;
1233         if (!udev_device->info_loaded)
1234                 udev_device_read_uevent_file(udev_device);
1235         return udev_device->devnode;
1236 }
1237
1238 /**
1239  * udev_device_get_devlinks_list_entry:
1240  * @udev_device: udev device
1241  *
1242  * Retrieve the list of device links pointing to the device file of
1243  * the udev device. The next list entry can be retrieved with
1244  * udev_list_entry_get_next(), which returns #NULL if no more entries exist.
1245  * The devlink path can be retrieved from the list entry by
1246  * udev_list_entry_get_name(). The path is an absolute path, and starts with
1247  * the device directory.
1248  *
1249  * Returns: the first entry of the device node link list
1250  **/
1251 _public_ struct udev_list_entry *udev_device_get_devlinks_list_entry(struct udev_device *udev_device)
1252 {
1253         if (udev_device == NULL)
1254                 return NULL;
1255         if (!udev_device->info_loaded)
1256                 udev_device_read_db(udev_device, NULL);
1257         return udev_list_get_entry(&udev_device->devlinks_list);
1258 }
1259
1260 void udev_device_cleanup_devlinks_list(struct udev_device *udev_device)
1261 {
1262         udev_device->devlinks_uptodate = false;
1263         udev_list_cleanup(&udev_device->devlinks_list);
1264 }
1265
1266 /**
1267  * udev_device_get_properties_list_entry:
1268  * @udev_device: udev device
1269  *
1270  * Retrieve the list of key/value device properties of the udev
1271  * device. The next list entry can be retrieved with udev_list_entry_get_next(),
1272  * which returns #NULL if no more entries exist. The property name
1273  * can be retrieved from the list entry by udev_list_entry_get_name(),
1274  * the property value by udev_list_entry_get_value().
1275  *
1276  * Returns: the first entry of the property list
1277  **/
1278 _public_ struct udev_list_entry *udev_device_get_properties_list_entry(struct udev_device *udev_device)
1279 {
1280         if (udev_device == NULL)
1281                 return NULL;
1282         if (!udev_device->info_loaded) {
1283                 udev_device_read_uevent_file(udev_device);
1284                 udev_device_read_db(udev_device, NULL);
1285         }
1286         if (!udev_device->devlinks_uptodate) {
1287                 char symlinks[UTIL_PATH_SIZE];
1288                 struct udev_list_entry *list_entry;
1289
1290                 udev_device->devlinks_uptodate = true;
1291                 list_entry = udev_device_get_devlinks_list_entry(udev_device);
1292                 if (list_entry != NULL) {
1293                         char *s;
1294                         size_t l;
1295
1296                         s = symlinks;
1297                         l = strpcpyl(&s, sizeof(symlinks), udev_list_entry_get_name(list_entry), NULL);
1298                         udev_list_entry_foreach(list_entry, udev_list_entry_get_next(list_entry))
1299                                 l = strpcpyl(&s, l, " ", udev_list_entry_get_name(list_entry), NULL);
1300                         udev_device_add_property(udev_device, "DEVLINKS", symlinks);
1301                 }
1302         }
1303         if (!udev_device->tags_uptodate) {
1304                 udev_device->tags_uptodate = true;
1305                 if (udev_device_get_tags_list_entry(udev_device) != NULL) {
1306                         char tags[UTIL_PATH_SIZE];
1307                         struct udev_list_entry *list_entry;
1308                         char *s;
1309                         size_t l;
1310
1311                         s = tags;
1312                         l = strpcpyl(&s, sizeof(tags), ":", NULL);
1313                         udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(udev_device))
1314                                 l = strpcpyl(&s, l, udev_list_entry_get_name(list_entry), ":", NULL);
1315                         udev_device_add_property(udev_device, "TAGS", tags);
1316                 }
1317         }
1318         return udev_list_get_entry(&udev_device->properties_list);
1319 }
1320
1321 /**
1322  * udev_device_get_action:
1323  * @udev_device: udev device
1324  *
1325  * This is only valid if the device was received through a monitor. Devices read from
1326  * sys do not have an action string. Usual actions are: add, remove, change, online,
1327  * offline.
1328  *
1329  * Returns: the kernel action value, or #NULL if there is no action value available.
1330  **/
1331 _public_ const char *udev_device_get_action(struct udev_device *udev_device)
1332 {
1333         if (udev_device == NULL)
1334                 return NULL;
1335         return udev_device->action;
1336 }
1337
1338 /**
1339  * udev_device_get_usec_since_initialized:
1340  * @udev_device: udev device
1341  *
1342  * Return the number of microseconds passed since udev set up the
1343  * device for the first time.
1344  *
1345  * This is only implemented for devices with need to store properties
1346  * in the udev database. All other devices return 0 here.
1347  *
1348  * Returns: the number of microseconds since the device was first seen.
1349  **/
1350 _public_ unsigned long long int udev_device_get_usec_since_initialized(struct udev_device *udev_device)
1351 {
1352         usec_t now_ts;
1353
1354         if (udev_device == NULL)
1355                 return 0;
1356         if (!udev_device->info_loaded)
1357                 udev_device_read_db(udev_device, NULL);
1358         if (udev_device->usec_initialized == 0)
1359                 return 0;
1360         now_ts = now(CLOCK_MONOTONIC);
1361         if (now_ts == 0)
1362                 return 0;
1363         return now_ts - udev_device->usec_initialized;
1364 }
1365
1366 usec_t udev_device_get_usec_initialized(struct udev_device *udev_device)
1367 {
1368         return udev_device->usec_initialized;
1369 }
1370
1371 void udev_device_set_usec_initialized(struct udev_device *udev_device, usec_t usec_initialized)
1372 {
1373         char num[32];
1374
1375         udev_device->usec_initialized = usec_initialized;
1376         snprintf(num, sizeof(num), USEC_FMT, usec_initialized);
1377         udev_device_add_property(udev_device, "USEC_INITIALIZED", num);
1378 }
1379
1380 /**
1381  * udev_device_get_sysattr_value:
1382  * @udev_device: udev device
1383  * @sysattr: attribute name
1384  *
1385  * The retrieved value is cached in the device. Repeated calls will return the same
1386  * value and not open the attribute again.
1387  *
1388  * Returns: the content of a sys attribute file, or #NULL if there is no sys attribute value.
1389  **/
1390 _public_ const char *udev_device_get_sysattr_value(struct udev_device *udev_device, const char *sysattr)
1391 {
1392         struct udev_list_entry *list_entry;
1393         char path[UTIL_PATH_SIZE];
1394         char value[4096];
1395         struct stat statbuf;
1396         int fd;
1397         ssize_t size;
1398         const char *val = NULL;
1399
1400         if (udev_device == NULL)
1401                 return NULL;
1402         if (sysattr == NULL)
1403                 return NULL;
1404
1405         /* look for possibly already cached result */
1406         list_entry = udev_list_get_entry(&udev_device->sysattr_value_list);
1407         list_entry = udev_list_entry_get_by_name(list_entry, sysattr);
1408         if (list_entry != NULL)
1409                 return udev_list_entry_get_value(list_entry);
1410
1411         strscpyl(path, sizeof(path), udev_device_get_syspath(udev_device), "/", sysattr, NULL);
1412         if (lstat(path, &statbuf) != 0) {
1413                 udev_list_entry_add(&udev_device->sysattr_value_list, sysattr, NULL);
1414                 goto out;
1415         }
1416
1417         if (S_ISLNK(statbuf.st_mode)) {
1418                 /*
1419                  * Some core links return only the last element of the target path,
1420                  * these are just values, the paths should not be exposed.
1421                  */
1422                 if (streq(sysattr, "driver") ||
1423                     streq(sysattr, "subsystem") ||
1424                     streq(sysattr, "module")) {
1425                         if (util_get_sys_core_link_value(udev_device->udev, sysattr,
1426                                                          udev_device->syspath, value, sizeof(value)) < 0)
1427                                 return NULL;
1428                         list_entry = udev_list_entry_add(&udev_device->sysattr_value_list, sysattr, value);
1429                         val = udev_list_entry_get_value(list_entry);
1430                         goto out;
1431                 }
1432
1433                 goto out;
1434         }
1435
1436         /* skip directories */
1437         if (S_ISDIR(statbuf.st_mode))
1438                 goto out;
1439
1440         /* skip non-readable files */
1441         if ((statbuf.st_mode & S_IRUSR) == 0)
1442                 goto out;
1443
1444         /* read attribute value */
1445         fd = open(path, O_RDONLY|O_CLOEXEC);
1446         if (fd < 0)
1447                 goto out;
1448         size = read(fd, value, sizeof(value));
1449         close(fd);
1450         if (size < 0)
1451                 goto out;
1452         if (size == sizeof(value))
1453                 goto out;
1454
1455         /* got a valid value, store it in cache and return it */
1456         value[size] = '\0';
1457         util_remove_trailing_chars(value, '\n');
1458         list_entry = udev_list_entry_add(&udev_device->sysattr_value_list, sysattr, value);
1459         val = udev_list_entry_get_value(list_entry);
1460 out:
1461         return val;
1462 }
1463
1464 /**
1465  * udev_device_set_sysattr_value:
1466  * @udev_device: udev device
1467  * @sysattr: attribute name
1468  * @value: new value to be set
1469  *
1470  * Update the contents of the sys attribute and the cached value of the device.
1471  *
1472  * Returns: Negative error code on failure or 0 on success.
1473  **/
1474 _public_ int udev_device_set_sysattr_value(struct udev_device *udev_device, const char *sysattr, char *value)
1475 {
1476         struct udev_device *dev;
1477         char path[UTIL_PATH_SIZE];
1478         struct stat statbuf;
1479         int fd;
1480         ssize_t size, value_len;
1481         int ret = 0;
1482
1483         if (udev_device == NULL)
1484                 return -EINVAL;
1485         dev = udev_device;
1486         if (sysattr == NULL)
1487                 return -EINVAL;
1488         if (value == NULL)
1489                 value_len = 0;
1490         else
1491                 value_len = strlen(value);
1492
1493         strscpyl(path, sizeof(path), udev_device_get_syspath(dev), "/", sysattr, NULL);
1494         if (lstat(path, &statbuf) != 0) {
1495                 udev_list_entry_add(&dev->sysattr_value_list, sysattr, NULL);
1496                 ret = -ENXIO;
1497                 goto out;
1498         }
1499
1500         if (S_ISLNK(statbuf.st_mode)) {
1501                 ret = -EINVAL;
1502                 goto out;
1503         }
1504
1505         /* skip directories */
1506         if (S_ISDIR(statbuf.st_mode)) {
1507                 ret = -EISDIR;
1508                 goto out;
1509         }
1510
1511         /* skip non-readable files */
1512         if ((statbuf.st_mode & S_IRUSR) == 0) {
1513                 ret = -EACCES;
1514                 goto out;
1515         }
1516
1517         /* Value is limited to 4k */
1518         if (value_len > 4096) {
1519                 ret = -EINVAL;
1520                 goto out;
1521         }
1522         util_remove_trailing_chars(value, '\n');
1523
1524         /* write attribute value */
1525         fd = open(path, O_WRONLY|O_CLOEXEC);
1526         if (fd < 0) {
1527                 ret = -errno;
1528                 goto out;
1529         }
1530         size = write(fd, value, value_len);
1531         close(fd);
1532         if (size < 0) {
1533                 ret = -errno;
1534                 goto out;
1535         }
1536         if (size < value_len) {
1537                 ret = -EIO;
1538                 goto out;
1539         }
1540
1541         /* wrote a valid value, store it in cache and return it */
1542         udev_list_entry_add(&dev->sysattr_value_list, sysattr, value);
1543 out:
1544         if (dev != udev_device)
1545                 udev_device_unref(dev);
1546         return ret;
1547 }
1548
1549 static int udev_device_sysattr_list_read(struct udev_device *udev_device)
1550 {
1551         struct dirent *dent;
1552         DIR *dir;
1553         int num = 0;
1554
1555         if (udev_device == NULL)
1556                 return -EINVAL;
1557         if (udev_device->sysattr_list_read)
1558                 return 0;
1559
1560         dir = opendir(udev_device_get_syspath(udev_device));
1561         if (!dir)
1562                 return -errno;
1563
1564         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
1565                 char path[UTIL_PATH_SIZE];
1566                 struct stat statbuf;
1567
1568                 /* only handle symlinks and regular files */
1569                 if (dent->d_type != DT_LNK && dent->d_type != DT_REG)
1570                         continue;
1571
1572                 strscpyl(path, sizeof(path), udev_device_get_syspath(udev_device), "/", dent->d_name, NULL);
1573                 if (lstat(path, &statbuf) != 0)
1574                         continue;
1575                 if ((statbuf.st_mode & S_IRUSR) == 0)
1576                         continue;
1577
1578                 udev_list_entry_add(&udev_device->sysattr_list, dent->d_name, NULL);
1579                 num++;
1580         }
1581
1582         closedir(dir);
1583         udev_device->sysattr_list_read = true;
1584
1585         return num;
1586 }
1587
1588 /**
1589  * udev_device_get_sysattr_list_entry:
1590  * @udev_device: udev device
1591  *
1592  * Retrieve the list of available sysattrs, with value being empty;
1593  * This just return all available sysfs attributes for a particular
1594  * device without reading their values.
1595  *
1596  * Returns: the first entry of the property list
1597  **/
1598 _public_ struct udev_list_entry *udev_device_get_sysattr_list_entry(struct udev_device *udev_device)
1599 {
1600         if (!udev_device->sysattr_list_read) {
1601                 int ret;
1602                 ret = udev_device_sysattr_list_read(udev_device);
1603                 if (0 > ret)
1604                         return NULL;
1605         }
1606
1607         return udev_list_get_entry(&udev_device->sysattr_list);
1608 }
1609
1610 int udev_device_set_syspath(struct udev_device *udev_device, const char *syspath)
1611 {
1612         const char *pos;
1613         size_t len;
1614
1615         free(udev_device->syspath);
1616         udev_device->syspath = strdup(syspath);
1617         if (udev_device->syspath ==  NULL)
1618                 return -ENOMEM;
1619         udev_device->devpath = udev_device->syspath + strlen("/sys");
1620         udev_device_add_property(udev_device, "DEVPATH", udev_device->devpath);
1621
1622         pos = strrchr(udev_device->syspath, '/');
1623         if (pos == NULL)
1624                 return -EINVAL;
1625         udev_device->sysname = strdup(&pos[1]);
1626         if (udev_device->sysname == NULL)
1627                 return -ENOMEM;
1628
1629         /* some devices have '!' in their name, change that to '/' */
1630         len = 0;
1631         while (udev_device->sysname[len] != '\0') {
1632                 if (udev_device->sysname[len] == '!')
1633                         udev_device->sysname[len] = '/';
1634                 len++;
1635         }
1636
1637         /* trailing number */
1638         while (len > 0 && isdigit(udev_device->sysname[--len]))
1639                 udev_device->sysnum = &udev_device->sysname[len];
1640
1641         /* sysname is completely numeric */
1642         if (len == 0)
1643                 udev_device->sysnum = NULL;
1644
1645         return 0;
1646 }
1647
1648 static int udev_device_set_devnode(struct udev_device *udev_device, const char *devnode)
1649 {
1650         free(udev_device->devnode);
1651         if (devnode[0] != '/') {
1652                 if (asprintf(&udev_device->devnode, "/dev/%s", devnode) < 0)
1653                         udev_device->devnode = NULL;
1654         } else {
1655                 udev_device->devnode = strdup(devnode);
1656         }
1657         if (udev_device->devnode == NULL)
1658                 return -ENOMEM;
1659         udev_device_add_property(udev_device, "DEVNAME", udev_device->devnode);
1660         return 0;
1661 }
1662
1663 int udev_device_add_devlink(struct udev_device *udev_device, const char *devlink)
1664 {
1665         struct udev_list_entry *list_entry;
1666
1667         udev_device->devlinks_uptodate = false;
1668         list_entry = udev_list_entry_add(&udev_device->devlinks_list, devlink, NULL);
1669         if (list_entry == NULL)
1670                 return -ENOMEM;
1671         return 0;
1672 }
1673
1674 const char *udev_device_get_id_filename(struct udev_device *udev_device)
1675 {
1676         if (udev_device->id_filename == NULL) {
1677                 if (udev_device_get_subsystem(udev_device) == NULL)
1678                         return NULL;
1679
1680                 if (major(udev_device_get_devnum(udev_device)) > 0) {
1681                         /* use dev_t -- b259:131072, c254:0 */
1682                         if (asprintf(&udev_device->id_filename, "%c%u:%u",
1683                                      streq(udev_device_get_subsystem(udev_device), "block") ? 'b' : 'c',
1684                                      major(udev_device_get_devnum(udev_device)),
1685                                      minor(udev_device_get_devnum(udev_device))) < 0)
1686                                 udev_device->id_filename = NULL;
1687                 } else if (udev_device_get_ifindex(udev_device) > 0) {
1688                         /* use netdev ifindex -- n3 */
1689                         if (asprintf(&udev_device->id_filename, "n%i", udev_device_get_ifindex(udev_device)) < 0)
1690                                 udev_device->id_filename = NULL;
1691                 } else {
1692                         /*
1693                          * use $subsys:$syname -- pci:0000:00:1f.2
1694                          * sysname() has '!' translated, get it from devpath
1695                          */
1696                         const char *sysname;
1697                         sysname = strrchr(udev_device->devpath, '/');
1698                         if (sysname == NULL)
1699                                 return NULL;
1700                         sysname = &sysname[1];
1701                         if (asprintf(&udev_device->id_filename, "+%s:%s", udev_device_get_subsystem(udev_device), sysname) < 0)
1702                                 udev_device->id_filename = NULL;
1703                 }
1704         }
1705         return udev_device->id_filename;
1706 }
1707
1708 /**
1709  * udev_device_get_is_initialized:
1710  * @udev_device: udev device
1711  *
1712  * Check if udev has already handled the device and has set up
1713  * device node permissions and context, or has renamed a network
1714  * device.
1715  *
1716  * This is only implemented for devices with a device node
1717  * or network interfaces. All other devices return 1 here.
1718  *
1719  * Returns: 1 if the device is set up. 0 otherwise.
1720  **/
1721 _public_ int udev_device_get_is_initialized(struct udev_device *udev_device)
1722 {
1723         if (!udev_device->info_loaded)
1724                 udev_device_read_db(udev_device, NULL);
1725         return udev_device->is_initialized;
1726 }
1727
1728 void udev_device_set_is_initialized(struct udev_device *udev_device)
1729 {
1730         udev_device->is_initialized = true;
1731 }
1732
1733 static bool is_valid_tag(const char *tag)
1734 {
1735         return !strchr(tag, ':') && !strchr(tag, ' ');
1736 }
1737
1738 int udev_device_add_tag(struct udev_device *udev_device, const char *tag)
1739 {
1740         if (!is_valid_tag(tag))
1741                 return -EINVAL;
1742         udev_device->tags_uptodate = false;
1743         if (udev_list_entry_add(&udev_device->tags_list, tag, NULL) != NULL)
1744                 return 0;
1745         return -ENOMEM;
1746 }
1747
1748 void udev_device_remove_tag(struct udev_device *udev_device, const char *tag)
1749 {
1750         struct udev_list_entry *e;
1751
1752         if (!is_valid_tag(tag))
1753                 return;
1754         e = udev_list_get_entry(&udev_device->tags_list);
1755         e = udev_list_entry_get_by_name(e, tag);
1756         if (e) {
1757                 udev_device->tags_uptodate = false;
1758                 udev_list_entry_delete(e);
1759         }
1760 }
1761
1762 void udev_device_cleanup_tags_list(struct udev_device *udev_device)
1763 {
1764         udev_device->tags_uptodate = false;
1765         udev_list_cleanup(&udev_device->tags_list);
1766 }
1767
1768 /**
1769  * udev_device_get_tags_list_entry:
1770  * @udev_device: udev device
1771  *
1772  * Retrieve the list of tags attached to the udev device. The next
1773  * list entry can be retrieved with udev_list_entry_get_next(),
1774  * which returns #NULL if no more entries exist. The tag string
1775  * can be retrieved from the list entry by udev_list_entry_get_name().
1776  *
1777  * Returns: the first entry of the tag list
1778  **/
1779 _public_ struct udev_list_entry *udev_device_get_tags_list_entry(struct udev_device *udev_device)
1780 {
1781         if (udev_device == NULL)
1782                 return NULL;
1783         if (!udev_device->info_loaded)
1784                 udev_device_read_db(udev_device, NULL);
1785         return udev_list_get_entry(&udev_device->tags_list);
1786 }
1787
1788 /**
1789  * udev_device_has_tag:
1790  * @udev_device: udev device
1791  * @tag: tag name
1792  *
1793  * Check if a given device has a certain tag associated.
1794  *
1795  * Returns: 1 if the tag is found. 0 otherwise.
1796  **/
1797 _public_ int udev_device_has_tag(struct udev_device *udev_device, const char *tag)
1798 {
1799         struct udev_list_entry *list_entry;
1800
1801         if (udev_device == NULL)
1802                 return false;
1803         if (!udev_device->info_loaded)
1804                 udev_device_read_db(udev_device, NULL);
1805         list_entry = udev_device_get_tags_list_entry(udev_device);
1806         if (udev_list_entry_get_by_name(list_entry, tag) != NULL)
1807                 return true;
1808         return false;
1809 }
1810
1811 #define ENVP_SIZE                        128
1812 #define MONITOR_BUF_SIZE                4096
1813 static int update_envp_monitor_buf(struct udev_device *udev_device)
1814 {
1815         struct udev_list_entry *list_entry;
1816         char *s;
1817         size_t l;
1818         unsigned int i;
1819
1820         /* monitor buffer of property strings */
1821         free(udev_device->monitor_buf);
1822         udev_device->monitor_buf_len = 0;
1823         udev_device->monitor_buf = malloc(MONITOR_BUF_SIZE);
1824         if (udev_device->monitor_buf == NULL)
1825                 return -ENOMEM;
1826
1827         /* envp array, strings will point into monitor buffer */
1828         if (udev_device->envp == NULL)
1829                 udev_device->envp = malloc(sizeof(char *) * ENVP_SIZE);
1830         if (udev_device->envp == NULL)
1831                 return -ENOMEM;
1832
1833         i = 0;
1834         s = udev_device->monitor_buf;
1835         l = MONITOR_BUF_SIZE;
1836         udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device)) {
1837                 const char *key;
1838
1839                 key = udev_list_entry_get_name(list_entry);
1840                 /* skip private variables */
1841                 if (key[0] == '.')
1842                         continue;
1843
1844                 /* add string to envp array */
1845                 udev_device->envp[i++] = s;
1846                 if (i+1 >= ENVP_SIZE)
1847                         return -EINVAL;
1848
1849                 /* add property string to monitor buffer */
1850                 l = strpcpyl(&s, l, key, "=", udev_list_entry_get_value(list_entry), NULL);
1851                 if (l == 0)
1852                         return -EINVAL;
1853                 /* advance past the trailing '\0' that strpcpyl() guarantees */
1854                 s++;
1855                 l--;
1856         }
1857         udev_device->envp[i] = NULL;
1858         udev_device->monitor_buf_len = s - udev_device->monitor_buf;
1859         udev_device->envp_uptodate = true;
1860         return 0;
1861 }
1862
1863 char **udev_device_get_properties_envp(struct udev_device *udev_device)
1864 {
1865         if (!udev_device->envp_uptodate)
1866                 if (update_envp_monitor_buf(udev_device) != 0)
1867                         return NULL;
1868         return udev_device->envp;
1869 }
1870
1871 ssize_t udev_device_get_properties_monitor_buf(struct udev_device *udev_device, const char **buf)
1872 {
1873         if (!udev_device->envp_uptodate)
1874                 if (update_envp_monitor_buf(udev_device) != 0)
1875                         return -EINVAL;
1876         *buf = udev_device->monitor_buf;
1877         return udev_device->monitor_buf_len;
1878 }
1879
1880 int udev_device_set_action(struct udev_device *udev_device, const char *action)
1881 {
1882         free(udev_device->action);
1883         udev_device->action = strdup(action);
1884         if (udev_device->action == NULL)
1885                 return -ENOMEM;
1886         udev_device_add_property(udev_device, "ACTION", udev_device->action);
1887         return 0;
1888 }
1889
1890 int udev_device_get_devlink_priority(struct udev_device *udev_device)
1891 {
1892         if (!udev_device->info_loaded)
1893                 udev_device_read_db(udev_device, NULL);
1894         return udev_device->devlink_priority;
1895 }
1896
1897 int udev_device_set_devlink_priority(struct udev_device *udev_device, int prio)
1898 {
1899          udev_device->devlink_priority = prio;
1900         return 0;
1901 }
1902
1903 int udev_device_get_watch_handle(struct udev_device *udev_device)
1904 {
1905         if (!udev_device->info_loaded)
1906                 udev_device_read_db(udev_device, NULL);
1907         return udev_device->watch_handle;
1908 }
1909
1910 int udev_device_set_watch_handle(struct udev_device *udev_device, int handle)
1911 {
1912         udev_device->watch_handle = handle;
1913         return 0;
1914 }
1915
1916 bool udev_device_get_db_persist(struct udev_device *udev_device)
1917 {
1918         return udev_device->db_persist;
1919 }
1920
1921 void udev_device_set_db_persist(struct udev_device *udev_device)
1922 {
1923         udev_device->db_persist = true;
1924 }
1925
1926 int udev_device_rename(struct udev_device *udev_device, const char *name)
1927 {
1928         _cleanup_free_ char *dirname = NULL;
1929         char *new_syspath;
1930         int r;
1931
1932         if (udev_device == NULL || name == NULL)
1933                 return -EINVAL;
1934
1935         dirname = dirname_malloc(udev_device->syspath);
1936         if (!dirname)
1937                 return -ENOMEM;
1938
1939         new_syspath = strappenda(dirname, "/", name);
1940
1941         r = udev_device_set_syspath(udev_device, new_syspath);
1942         if (r < 0)
1943                 return r;
1944
1945         return 0;
1946 }