chiark / gitweb /
getty-generator: fix stripping /dev/
[elogind.git] / 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 static 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                 udev_dbg(udev_device->udev, "no db file to read %s: %m\n", dbfile);
539                 return -errno;
540         }
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         udev_dbg(udev_device->udev, "device %p filled with db file data\n", 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         struct udev_list_entry *list_entry;
644
645         if (udev == NULL)
646                 return NULL;
647
648         udev_device = calloc(1, sizeof(struct udev_device));
649         if (udev_device == NULL)
650                 return NULL;
651         udev_device->refcount = 1;
652         udev_device->udev = udev;
653         udev_list_init(udev, &udev_device->devlinks_list, true);
654         udev_list_init(udev, &udev_device->properties_list, true);
655         udev_list_init(udev, &udev_device->sysattr_value_list, true);
656         udev_list_init(udev, &udev_device->sysattr_list, false);
657         udev_list_init(udev, &udev_device->tags_list, true);
658         udev_device->watch_handle = -1;
659         /* copy global properties */
660         udev_list_entry_foreach(list_entry, udev_get_properties_list_entry(udev))
661                 udev_device_add_property(udev_device,
662                                          udev_list_entry_get_name(list_entry),
663                                          udev_list_entry_get_value(list_entry));
664         return udev_device;
665 }
666
667 /**
668  * udev_device_new_from_syspath:
669  * @udev: udev library context
670  * @syspath: sys device path including sys directory
671  *
672  * Create new udev device, and fill in information from the sys
673  * device and the udev database entry. The syspath is the absolute
674  * path to the device, including the sys mount point.
675  *
676  * The initial refcount is 1, and needs to be decremented to
677  * release the resources of the udev device.
678  *
679  * Returns: a new udev device, or #NULL, if it does not exist
680  **/
681 _public_ struct udev_device *udev_device_new_from_syspath(struct udev *udev, const char *syspath)
682 {
683         const char *subdir;
684         char path[UTIL_PATH_SIZE];
685         char *pos;
686         struct stat statbuf;
687         struct udev_device *udev_device;
688
689         if (udev == NULL)
690                 return NULL;
691         if (syspath == NULL)
692                 return NULL;
693
694         /* path starts in sys */
695         if (!startswith(syspath, "/sys")) {
696                 udev_dbg(udev, "not in sys :%s\n", syspath);
697                 return NULL;
698         }
699
700         /* path is not a root directory */
701         subdir = syspath + strlen("/sys");
702         pos = strrchr(subdir, '/');
703         if (pos == NULL || pos[1] == '\0' || pos < &subdir[2])
704                 return NULL;
705
706         /* resolve possible symlink to real path */
707         strscpy(path, sizeof(path), syspath);
708         util_resolve_sys_link(udev, path, sizeof(path));
709
710         if (startswith(path + strlen("/sys"), "/devices/")) {
711                 char file[UTIL_PATH_SIZE];
712
713                 /* all "devices" require a "uevent" file */
714                 strscpyl(file, sizeof(file), path, "/uevent", NULL);
715                 if (stat(file, &statbuf) != 0)
716                         return NULL;
717         } else {
718                 /* everything else just needs to be a directory */
719                 if (stat(path, &statbuf) != 0 || !S_ISDIR(statbuf.st_mode))
720                         return NULL;
721         }
722
723         udev_device = udev_device_new(udev);
724         if (udev_device == NULL)
725                 return NULL;
726
727         udev_device_set_syspath(udev_device, path);
728         udev_dbg(udev, "device %p has devpath '%s'\n", udev_device, udev_device_get_devpath(udev_device));
729
730         return udev_device;
731 }
732
733 /**
734  * udev_device_new_from_devnum:
735  * @udev: udev library context
736  * @type: char or block device
737  * @devnum: device major/minor number
738  *
739  * Create new udev device, and fill in information from the sys
740  * device and the udev database entry. The device is looked-up
741  * by its major/minor number and type. Character and block device
742  * numbers are not unique across the two types.
743  *
744  * The initial refcount is 1, and needs to be decremented to
745  * release the resources of the udev device.
746  *
747  * Returns: a new udev device, or #NULL, if it does not exist
748  **/
749 _public_ struct udev_device *udev_device_new_from_devnum(struct udev *udev, char type, dev_t devnum)
750 {
751         char path[UTIL_PATH_SIZE];
752         const char *type_str;
753
754         if (type == 'b')
755                 type_str = "block";
756         else if (type == 'c')
757                 type_str = "char";
758         else
759                 return NULL;
760
761         /* use /sys/dev/{block,char}/<maj>:<min> link */
762         snprintf(path, sizeof(path), "/sys/dev/%s/%u:%u",
763                  type_str, major(devnum), minor(devnum));
764         return udev_device_new_from_syspath(udev, path);
765 }
766
767 /**
768  * udev_device_new_from_device_id:
769  * @udev: udev library context
770  * @id: text string identifying a kernel device
771  *
772  * Create new udev device, and fill in information from the sys
773  * device and the udev database entry. The device is looked-up
774  * by a special string:
775  *   b8:2          - block device major:minor
776  *   c128:1        - char device major:minor
777  *   n3            - network device ifindex
778  *   +sound:card29 - kernel driver core subsystem:device name
779  *
780  * The initial refcount is 1, and needs to be decremented to
781  * release the resources of the udev device.
782  *
783  * Returns: a new udev device, or #NULL, if it does not exist
784  **/
785 _public_ struct udev_device *udev_device_new_from_device_id(struct udev *udev, const char *id)
786 {
787         char type;
788         int maj, min;
789         char subsys[UTIL_PATH_SIZE];
790         char *sysname;
791
792         switch(id[0]) {
793         case 'b':
794         case 'c':
795                 if (sscanf(id, "%c%i:%i", &type, &maj, &min) != 3)
796                         return NULL;
797                 return udev_device_new_from_devnum(udev, type, makedev(maj, min));
798         case 'n': {
799                 int sk;
800                 struct ifreq ifr;
801                 struct udev_device *dev;
802                 int ifindex;
803
804                 ifindex = strtoul(&id[1], NULL, 10);
805                 if (ifindex <= 0)
806                         return NULL;
807
808                 sk = socket(PF_INET, SOCK_DGRAM, 0);
809                 if (sk < 0)
810                         return NULL;
811                 memset(&ifr, 0x00, sizeof(struct ifreq));
812                 ifr.ifr_ifindex = ifindex;
813                 if (ioctl(sk, SIOCGIFNAME, &ifr) != 0) {
814                         close(sk);
815                         return NULL;
816                 }
817                 close(sk);
818
819                 dev = udev_device_new_from_subsystem_sysname(udev, "net", ifr.ifr_name);
820                 if (dev == NULL)
821                         return NULL;
822                 if (udev_device_get_ifindex(dev) == ifindex)
823                         return dev;
824                 udev_device_unref(dev);
825                 return NULL;
826         }
827         case '+':
828                 strscpy(subsys, sizeof(subsys), &id[1]);
829                 sysname = strchr(subsys, ':');
830                 if (sysname == NULL)
831                         return NULL;
832                 sysname[0] = '\0';
833                 sysname = &sysname[1];
834                 return udev_device_new_from_subsystem_sysname(udev, subsys, sysname);
835         default:
836                 return NULL;
837         }
838 }
839
840 /**
841  * udev_device_new_from_subsystem_sysname:
842  * @udev: udev library context
843  * @subsystem: the subsystem of the device
844  * @sysname: the name of the device
845  *
846  * Create new udev device, and fill in information from the sys device
847  * and the udev database entry. The device is looked up by the subsystem
848  * and name string of the device, like "mem" / "zero", or "block" / "sda".
849  *
850  * The initial refcount is 1, and needs to be decremented to
851  * release the resources of the udev device.
852  *
853  * Returns: a new udev device, or #NULL, if it does not exist
854  **/
855 _public_ struct udev_device *udev_device_new_from_subsystem_sysname(struct udev *udev, const char *subsystem, const char *sysname)
856 {
857         char path[UTIL_PATH_SIZE];
858         struct stat statbuf;
859
860         if (streq(subsystem, "subsystem")) {
861                 strscpyl(path, sizeof(path), "/sys/subsystem/", sysname, NULL);
862                 if (stat(path, &statbuf) == 0)
863                         goto found;
864
865                 strscpyl(path, sizeof(path), "/sys/bus/", sysname, NULL);
866                 if (stat(path, &statbuf) == 0)
867                         goto found;
868
869                 strscpyl(path, sizeof(path), "/sys/class/", sysname, NULL);
870                 if (stat(path, &statbuf) == 0)
871                         goto found;
872                 goto out;
873         }
874
875         if (streq(subsystem, "module")) {
876                 strscpyl(path, sizeof(path), "/sys/module/", sysname, NULL);
877                 if (stat(path, &statbuf) == 0)
878                         goto found;
879                 goto out;
880         }
881
882         if (streq(subsystem, "drivers")) {
883                 char subsys[UTIL_NAME_SIZE];
884                 char *driver;
885
886                 strscpy(subsys, sizeof(subsys), sysname);
887                 driver = strchr(subsys, ':');
888                 if (driver != NULL) {
889                         driver[0] = '\0';
890                         driver = &driver[1];
891
892                         strscpyl(path, sizeof(path), "/sys/subsystem/", subsys, "/drivers/", driver, NULL);
893                         if (stat(path, &statbuf) == 0)
894                                 goto found;
895
896                         strscpyl(path, sizeof(path), "/sys/bus/", subsys, "/drivers/", driver, NULL);
897                         if (stat(path, &statbuf) == 0)
898                                 goto found;
899                 }
900                 goto out;
901         }
902
903         strscpyl(path, sizeof(path), "/sys/subsystem/", subsystem, "/devices/", sysname, NULL);
904         if (stat(path, &statbuf) == 0)
905                 goto found;
906
907         strscpyl(path, sizeof(path), "/sys/bus/", subsystem, "/devices/", sysname, NULL);
908         if (stat(path, &statbuf) == 0)
909                 goto found;
910
911         strscpyl(path, sizeof(path), "/sys/class/", subsystem, "/", sysname, NULL);
912         if (stat(path, &statbuf) == 0)
913                 goto found;
914 out:
915         return NULL;
916 found:
917         return udev_device_new_from_syspath(udev, path);
918 }
919
920 /**
921  * udev_device_new_from_environment
922  * @udev: udev library context
923  *
924  * Create new udev device, and fill in information from the
925  * current process environment. This only works reliable if
926  * the process is called from a udev rule. It is usually used
927  * for tools executed from IMPORT= rules.
928  *
929  * The initial refcount is 1, and needs to be decremented to
930  * release the resources of the udev device.
931  *
932  * Returns: a new udev device, or #NULL, if it does not exist
933  **/
934 _public_ struct udev_device *udev_device_new_from_environment(struct udev *udev)
935 {
936         int i;
937         struct udev_device *udev_device;
938
939         udev_device = udev_device_new(udev);
940         if (udev_device == NULL)
941                 return NULL;
942         udev_device_set_info_loaded(udev_device);
943
944         for (i = 0; environ[i] != NULL; i++)
945                 udev_device_add_property_from_string_parse(udev_device, environ[i]);
946
947         if (udev_device_add_property_from_string_parse_finish(udev_device) < 0) {
948                 udev_dbg(udev, "missing values, invalid device\n");
949                 udev_device_unref(udev_device);
950                 udev_device = NULL;
951         }
952
953         return udev_device;
954 }
955
956 static struct udev_device *device_new_from_parent(struct udev_device *udev_device)
957 {
958         struct udev_device *udev_device_parent = NULL;
959         char path[UTIL_PATH_SIZE];
960         const char *subdir;
961
962         strscpy(path, sizeof(path), udev_device->syspath);
963         subdir = path + strlen("/sys/");
964         for (;;) {
965                 char *pos;
966
967                 pos = strrchr(subdir, '/');
968                 if (pos == NULL || pos < &subdir[2])
969                         break;
970                 pos[0] = '\0';
971                 udev_device_parent = udev_device_new_from_syspath(udev_device->udev, path);
972                 if (udev_device_parent != NULL)
973                         return udev_device_parent;
974         }
975         return NULL;
976 }
977
978 /**
979  * udev_device_get_parent:
980  * @udev_device: the device to start searching from
981  *
982  * Find the next parent device, and fill in information from the sys
983  * device and the udev database entry.
984  *
985  * Returned device is not referenced. It is attached to the child
986  * device, and will be cleaned up when the child device is cleaned up.
987  *
988  * It is not necessarily just the upper level directory, empty or not
989  * recognized sys directories are ignored.
990  *
991  * It can be called as many times as needed, without caring about
992  * references.
993  *
994  * Returns: a new udev device, or #NULL, if it no parent exist.
995  **/
996 _public_ struct udev_device *udev_device_get_parent(struct udev_device *udev_device)
997 {
998         if (udev_device == NULL)
999                 return NULL;
1000         if (!udev_device->parent_set) {
1001                 udev_device->parent_set = true;
1002                 udev_device->parent_device = device_new_from_parent(udev_device);
1003         }
1004         return udev_device->parent_device;
1005 }
1006
1007 /**
1008  * udev_device_get_parent_with_subsystem_devtype:
1009  * @udev_device: udev device to start searching from
1010  * @subsystem: the subsystem of the device
1011  * @devtype: the type (DEVTYPE) of the device
1012  *
1013  * Find the next parent device, with a matching subsystem and devtype
1014  * value, and fill in information from the sys device and the udev
1015  * database entry.
1016  *
1017  * If devtype is #NULL, only subsystem is checked, and any devtype will
1018  * match.
1019  *
1020  * Returned device is not referenced. It is attached to the child
1021  * device, and will be cleaned up when the child device is cleaned up.
1022  *
1023  * It can be called as many times as needed, without caring about
1024  * references.
1025  *
1026  * Returns: a new udev device, or #NULL if no matching parent exists.
1027  **/
1028 _public_ struct udev_device *udev_device_get_parent_with_subsystem_devtype(struct udev_device *udev_device, const char *subsystem, const char *devtype)
1029 {
1030         struct udev_device *parent;
1031
1032         if (subsystem == NULL)
1033                 return NULL;
1034
1035         parent = udev_device_get_parent(udev_device);
1036         while (parent != NULL) {
1037                 const char *parent_subsystem;
1038                 const char *parent_devtype;
1039
1040                 parent_subsystem = udev_device_get_subsystem(parent);
1041                 if (parent_subsystem != NULL && streq(parent_subsystem, subsystem)) {
1042                         if (devtype == NULL)
1043                                 break;
1044                         parent_devtype = udev_device_get_devtype(parent);
1045                         if (parent_devtype != NULL && streq(parent_devtype, devtype))
1046                                 break;
1047                 }
1048                 parent = udev_device_get_parent(parent);
1049         }
1050         return parent;
1051 }
1052
1053 /**
1054  * udev_device_get_udev:
1055  * @udev_device: udev device
1056  *
1057  * Retrieve the udev library context the device was created with.
1058  *
1059  * Returns: the udev library context
1060  **/
1061 _public_ struct udev *udev_device_get_udev(struct udev_device *udev_device)
1062 {
1063         if (udev_device == NULL)
1064                 return NULL;
1065         return udev_device->udev;
1066 }
1067
1068 /**
1069  * udev_device_ref:
1070  * @udev_device: udev device
1071  *
1072  * Take a reference of a udev device.
1073  *
1074  * Returns: the passed udev device
1075  **/
1076 _public_ struct udev_device *udev_device_ref(struct udev_device *udev_device)
1077 {
1078         if (udev_device == NULL)
1079                 return NULL;
1080         udev_device->refcount++;
1081         return udev_device;
1082 }
1083
1084 /**
1085  * udev_device_unref:
1086  * @udev_device: udev device
1087  *
1088  * Drop a reference of a udev device. If the refcount reaches zero,
1089  * the resources of the device will be released.
1090  *
1091  * Returns: #NULL
1092  **/
1093 _public_ struct udev_device *udev_device_unref(struct udev_device *udev_device)
1094 {
1095         if (udev_device == NULL)
1096                 return NULL;
1097         udev_device->refcount--;
1098         if (udev_device->refcount > 0)
1099                 return NULL;
1100         if (udev_device->parent_device != NULL)
1101                 udev_device_unref(udev_device->parent_device);
1102         free(udev_device->syspath);
1103         free(udev_device->sysname);
1104         free(udev_device->devnode);
1105         free(udev_device->subsystem);
1106         free(udev_device->devtype);
1107         udev_list_cleanup(&udev_device->devlinks_list);
1108         udev_list_cleanup(&udev_device->properties_list);
1109         udev_list_cleanup(&udev_device->sysattr_value_list);
1110         udev_list_cleanup(&udev_device->sysattr_list);
1111         udev_list_cleanup(&udev_device->tags_list);
1112         free(udev_device->action);
1113         free(udev_device->driver);
1114         free(udev_device->devpath_old);
1115         free(udev_device->id_filename);
1116         free(udev_device->envp);
1117         free(udev_device->monitor_buf);
1118         free(udev_device);
1119         return NULL;
1120 }
1121
1122 /**
1123  * udev_device_get_devpath:
1124  * @udev_device: udev device
1125  *
1126  * Retrieve the kernel devpath value of the udev device. The path
1127  * does not contain the sys mount point, and starts with a '/'.
1128  *
1129  * Returns: the devpath of the udev device
1130  **/
1131 _public_ const char *udev_device_get_devpath(struct udev_device *udev_device)
1132 {
1133         if (udev_device == NULL)
1134                 return NULL;
1135         return udev_device->devpath;
1136 }
1137
1138 /**
1139  * udev_device_get_syspath:
1140  * @udev_device: udev device
1141  *
1142  * Retrieve the sys path of the udev device. The path is an
1143  * absolute path and starts with the sys mount point.
1144  *
1145  * Returns: the sys path of the udev device
1146  **/
1147 _public_ const char *udev_device_get_syspath(struct udev_device *udev_device)
1148 {
1149         if (udev_device == NULL)
1150                 return NULL;
1151         return udev_device->syspath;
1152 }
1153
1154 /**
1155  * udev_device_get_sysname:
1156  * @udev_device: udev device
1157  *
1158  * Get the kernel device name in /sys.
1159  *
1160  * Returns: the name string of the device device
1161  **/
1162 _public_ const char *udev_device_get_sysname(struct udev_device *udev_device)
1163 {
1164         if (udev_device == NULL)
1165                 return NULL;
1166         return udev_device->sysname;
1167 }
1168
1169 /**
1170  * udev_device_get_sysnum:
1171  * @udev_device: udev device
1172  *
1173  * Get the instance number of the device.
1174  *
1175  * Returns: the trailing number string of the device name
1176  **/
1177 _public_ const char *udev_device_get_sysnum(struct udev_device *udev_device)
1178 {
1179         if (udev_device == NULL)
1180                 return NULL;
1181         return udev_device->sysnum;
1182 }
1183
1184 /**
1185  * udev_device_get_devnode:
1186  * @udev_device: udev device
1187  *
1188  * Retrieve the device node file name belonging to the udev device.
1189  * The path is an absolute path, and starts with the device directory.
1190  *
1191  * Returns: the device node file name of the udev device, or #NULL if no device node exists
1192  **/
1193 _public_ const char *udev_device_get_devnode(struct udev_device *udev_device)
1194 {
1195         if (udev_device == NULL)
1196                 return NULL;
1197         if (udev_device->devnode != NULL)
1198                 return udev_device->devnode;
1199         if (!udev_device->info_loaded)
1200                 udev_device_read_uevent_file(udev_device);
1201         return udev_device->devnode;
1202 }
1203
1204 /**
1205  * udev_device_get_devlinks_list_entry:
1206  * @udev_device: udev device
1207  *
1208  * Retrieve the list of device links pointing to the device file of
1209  * the udev device. The next list entry can be retrieved with
1210  * udev_list_entry_get_next(), which returns #NULL if no more entries exist.
1211  * The devlink path can be retrieved from the list entry by
1212  * udev_list_entry_get_name(). The path is an absolute path, and starts with
1213  * the device directory.
1214  *
1215  * Returns: the first entry of the device node link list
1216  **/
1217 _public_ struct udev_list_entry *udev_device_get_devlinks_list_entry(struct udev_device *udev_device)
1218 {
1219         if (udev_device == NULL)
1220                 return NULL;
1221         if (!udev_device->info_loaded)
1222                 udev_device_read_db(udev_device, NULL);
1223         return udev_list_get_entry(&udev_device->devlinks_list);
1224 }
1225
1226 void udev_device_cleanup_devlinks_list(struct udev_device *udev_device)
1227 {
1228         udev_device->devlinks_uptodate = false;
1229         udev_list_cleanup(&udev_device->devlinks_list);
1230 }
1231
1232 /**
1233  * udev_device_get_properties_list_entry:
1234  * @udev_device: udev device
1235  *
1236  * Retrieve the list of key/value device properties of the udev
1237  * device. The next list entry can be retrieved with udev_list_entry_get_next(),
1238  * which returns #NULL if no more entries exist. The property name
1239  * can be retrieved from the list entry by udev_list_entry_get_name(),
1240  * the property value by udev_list_entry_get_value().
1241  *
1242  * Returns: the first entry of the property list
1243  **/
1244 _public_ struct udev_list_entry *udev_device_get_properties_list_entry(struct udev_device *udev_device)
1245 {
1246         if (udev_device == NULL)
1247                 return NULL;
1248         if (!udev_device->info_loaded) {
1249                 udev_device_read_uevent_file(udev_device);
1250                 udev_device_read_db(udev_device, NULL);
1251         }
1252         if (!udev_device->devlinks_uptodate) {
1253                 char symlinks[UTIL_PATH_SIZE];
1254                 struct udev_list_entry *list_entry;
1255
1256                 udev_device->devlinks_uptodate = true;
1257                 list_entry = udev_device_get_devlinks_list_entry(udev_device);
1258                 if (list_entry != NULL) {
1259                         char *s;
1260                         size_t l;
1261
1262                         s = symlinks;
1263                         l = strpcpyl(&s, sizeof(symlinks), udev_list_entry_get_name(list_entry), NULL);
1264                         udev_list_entry_foreach(list_entry, udev_list_entry_get_next(list_entry))
1265                                 l = strpcpyl(&s, l, " ", udev_list_entry_get_name(list_entry), NULL);
1266                         udev_device_add_property(udev_device, "DEVLINKS", symlinks);
1267                 }
1268         }
1269         if (!udev_device->tags_uptodate) {
1270                 udev_device->tags_uptodate = true;
1271                 if (udev_device_get_tags_list_entry(udev_device) != NULL) {
1272                         char tags[UTIL_PATH_SIZE];
1273                         struct udev_list_entry *list_entry;
1274                         char *s;
1275                         size_t l;
1276
1277                         s = tags;
1278                         l = strpcpyl(&s, sizeof(tags), ":", NULL);
1279                         udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(udev_device))
1280                                 l = strpcpyl(&s, l, udev_list_entry_get_name(list_entry), ":", NULL);
1281                         udev_device_add_property(udev_device, "TAGS", tags);
1282                 }
1283         }
1284         return udev_list_get_entry(&udev_device->properties_list);
1285 }
1286
1287 /**
1288  * udev_device_get_action:
1289  * @udev_device: udev device
1290  *
1291  * This is only valid if the device was received through a monitor. Devices read from
1292  * sys do not have an action string. Usual actions are: add, remove, change, online,
1293  * offline.
1294  *
1295  * Returns: the kernel action value, or #NULL if there is no action value available.
1296  **/
1297 _public_ const char *udev_device_get_action(struct udev_device *udev_device)
1298 {
1299         if (udev_device == NULL)
1300                 return NULL;
1301         return udev_device->action;
1302 }
1303
1304 /**
1305  * udev_device_get_usec_since_initialized:
1306  * @udev_device: udev device
1307  *
1308  * Return the number of microseconds passed since udev set up the
1309  * device for the first time.
1310  *
1311  * This is only implemented for devices with need to store properties
1312  * in the udev database. All other devices return 0 here.
1313  *
1314  * Returns: the number of microseconds since the device was first seen.
1315  **/
1316 _public_ unsigned long long int udev_device_get_usec_since_initialized(struct udev_device *udev_device)
1317 {
1318         usec_t now_ts;
1319
1320         if (udev_device == NULL)
1321                 return 0;
1322         if (!udev_device->info_loaded)
1323                 udev_device_read_db(udev_device, NULL);
1324         if (udev_device->usec_initialized == 0)
1325                 return 0;
1326         now_ts = now(CLOCK_MONOTONIC);
1327         if (now_ts == 0)
1328                 return 0;
1329         return now_ts - udev_device->usec_initialized;
1330 }
1331
1332 usec_t udev_device_get_usec_initialized(struct udev_device *udev_device)
1333 {
1334         return udev_device->usec_initialized;
1335 }
1336
1337 void udev_device_set_usec_initialized(struct udev_device *udev_device, usec_t usec_initialized)
1338 {
1339         char num[32];
1340
1341         udev_device->usec_initialized = usec_initialized;
1342         snprintf(num, sizeof(num), "%llu", (unsigned long long)usec_initialized);
1343         udev_device_add_property(udev_device, "USEC_INITIALIZED", num);
1344 }
1345
1346 /**
1347  * udev_device_get_sysattr_value:
1348  * @udev_device: udev device
1349  * @sysattr: attribute name
1350  *
1351  * The retrieved value is cached in the device. Repeated calls will return the same
1352  * value and not open the attribute again.
1353  *
1354  * Returns: the content of a sys attribute file, or #NULL if there is no sys attribute value.
1355  **/
1356 _public_ const char *udev_device_get_sysattr_value(struct udev_device *udev_device, const char *sysattr)
1357 {
1358         struct udev_list_entry *list_entry;
1359         char path[UTIL_PATH_SIZE];
1360         char value[4096];
1361         struct stat statbuf;
1362         int fd;
1363         ssize_t size;
1364         const char *val = NULL;
1365
1366         if (udev_device == NULL)
1367                 return NULL;
1368         if (sysattr == NULL)
1369                 return NULL;
1370
1371         /* look for possibly already cached result */
1372         list_entry = udev_list_get_entry(&udev_device->sysattr_value_list);
1373         list_entry = udev_list_entry_get_by_name(list_entry, sysattr);
1374         if (list_entry != NULL)
1375                 return udev_list_entry_get_value(list_entry);
1376
1377         strscpyl(path, sizeof(path), udev_device_get_syspath(udev_device), "/", sysattr, NULL);
1378         if (lstat(path, &statbuf) != 0) {
1379                 udev_list_entry_add(&udev_device->sysattr_value_list, sysattr, NULL);
1380                 goto out;
1381         }
1382
1383         if (S_ISLNK(statbuf.st_mode)) {
1384                 /*
1385                  * Some core links return only the last element of the target path,
1386                  * these are just values, the paths should not be exposed.
1387                  */
1388                 if (streq(sysattr, "driver") ||
1389                     streq(sysattr, "subsystem") ||
1390                     streq(sysattr, "module")) {
1391                         if (util_get_sys_core_link_value(udev_device->udev, sysattr,
1392                                                          udev_device->syspath, value, sizeof(value)) < 0)
1393                                 return NULL;
1394                         list_entry = udev_list_entry_add(&udev_device->sysattr_value_list, sysattr, value);
1395                         val = udev_list_entry_get_value(list_entry);
1396                         goto out;
1397                 }
1398
1399                 goto out;
1400         }
1401
1402         /* skip directories */
1403         if (S_ISDIR(statbuf.st_mode))
1404                 goto out;
1405
1406         /* skip non-readable files */
1407         if ((statbuf.st_mode & S_IRUSR) == 0)
1408                 goto out;
1409
1410         /* read attribute value */
1411         fd = open(path, O_RDONLY|O_CLOEXEC);
1412         if (fd < 0)
1413                 goto out;
1414         size = read(fd, value, sizeof(value));
1415         close(fd);
1416         if (size < 0)
1417                 goto out;
1418         if (size == sizeof(value))
1419                 goto out;
1420
1421         /* got a valid value, store it in cache and return it */
1422         value[size] = '\0';
1423         util_remove_trailing_chars(value, '\n');
1424         list_entry = udev_list_entry_add(&udev_device->sysattr_value_list, sysattr, value);
1425         val = udev_list_entry_get_value(list_entry);
1426 out:
1427         return val;
1428 }
1429
1430 /**
1431  * udev_device_set_sysattr_value:
1432  * @udev_device: udev device
1433  * @sysattr: attribute name
1434  * @value: new value to be set
1435  *
1436  * Update the contents of the sys attribute and the cached value of the device.
1437  *
1438  * Returns: Negative error code on failure or 0 on success.
1439  **/
1440 _public_ int udev_device_set_sysattr_value(struct udev_device *udev_device, const char *sysattr, char *value)
1441 {
1442         struct udev_device *dev;
1443         char path[UTIL_PATH_SIZE];
1444         struct stat statbuf;
1445         int fd;
1446         ssize_t size, value_len;
1447         int ret = 0;
1448
1449         if (udev_device == NULL)
1450                 return -EINVAL;
1451         dev = udev_device;
1452         if (sysattr == NULL)
1453                 return -EINVAL;
1454         if (value == NULL)
1455                 value_len = 0;
1456         else
1457                 value_len = strlen(value);
1458
1459         strscpyl(path, sizeof(path), udev_device_get_syspath(dev), "/", sysattr, NULL);
1460         if (lstat(path, &statbuf) != 0) {
1461                 udev_list_entry_add(&dev->sysattr_value_list, sysattr, NULL);
1462                 ret = -ENXIO;
1463                 goto out;
1464         }
1465
1466         if (S_ISLNK(statbuf.st_mode)) {
1467                 ret = -EINVAL;
1468                 goto out;
1469         }
1470
1471         /* skip directories */
1472         if (S_ISDIR(statbuf.st_mode)) {
1473                 ret = -EISDIR;
1474                 goto out;
1475         }
1476
1477         /* skip non-readable files */
1478         if ((statbuf.st_mode & S_IRUSR) == 0) {
1479                 ret = -EACCES;
1480                 goto out;
1481         }
1482
1483         /* Value is limited to 4k */
1484         if (value_len > 4096) {
1485                 ret = -EINVAL;
1486                 goto out;
1487         }
1488         util_remove_trailing_chars(value, '\n');
1489
1490         /* write attribute value */
1491         fd = open(path, O_WRONLY|O_CLOEXEC);
1492         if (fd < 0) {
1493                 ret = -errno;
1494                 goto out;
1495         }
1496         size = write(fd, value, value_len);
1497         close(fd);
1498         if (size < 0) {
1499                 ret = -errno;
1500                 goto out;
1501         }
1502         if (size < value_len) {
1503                 ret = -EIO;
1504                 goto out;
1505         }
1506
1507         /* wrote a valid value, store it in cache and return it */
1508         udev_list_entry_add(&dev->sysattr_value_list, sysattr, value);
1509 out:
1510         if (dev != udev_device)
1511                 udev_device_unref(dev);
1512         return ret;
1513 }
1514
1515 static int udev_device_sysattr_list_read(struct udev_device *udev_device)
1516 {
1517         struct dirent *dent;
1518         DIR *dir;
1519         int num = 0;
1520
1521         if (udev_device == NULL)
1522                 return -EINVAL;
1523         if (udev_device->sysattr_list_read)
1524                 return 0;
1525
1526         dir = opendir(udev_device_get_syspath(udev_device));
1527         if (!dir)
1528                 return -errno;
1529
1530         for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
1531                 char path[UTIL_PATH_SIZE];
1532                 struct stat statbuf;
1533
1534                 /* only handle symlinks and regular files */
1535                 if (dent->d_type != DT_LNK && dent->d_type != DT_REG)
1536                         continue;
1537
1538                 strscpyl(path, sizeof(path), udev_device_get_syspath(udev_device), "/", dent->d_name, NULL);
1539                 if (lstat(path, &statbuf) != 0)
1540                         continue;
1541                 if ((statbuf.st_mode & S_IRUSR) == 0)
1542                         continue;
1543
1544                 udev_list_entry_add(&udev_device->sysattr_list, dent->d_name, NULL);
1545                 num++;
1546         }
1547
1548         closedir(dir);
1549         udev_device->sysattr_list_read = true;
1550
1551         return num;
1552 }
1553
1554 /**
1555  * udev_device_get_sysattr_list_entry:
1556  * @udev_device: udev device
1557  *
1558  * Retrieve the list of available sysattrs, with value being empty;
1559  * This just return all available sysfs attributes for a particular
1560  * device without reading their values.
1561  *
1562  * Returns: the first entry of the property list
1563  **/
1564 _public_ struct udev_list_entry *udev_device_get_sysattr_list_entry(struct udev_device *udev_device)
1565 {
1566         if (!udev_device->sysattr_list_read) {
1567                 int ret;
1568                 ret = udev_device_sysattr_list_read(udev_device);
1569                 if (0 > ret)
1570                         return NULL;
1571         }
1572
1573         return udev_list_get_entry(&udev_device->sysattr_list);
1574 }
1575
1576 int udev_device_set_syspath(struct udev_device *udev_device, const char *syspath)
1577 {
1578         const char *pos;
1579         size_t len;
1580
1581         free(udev_device->syspath);
1582         udev_device->syspath = strdup(syspath);
1583         if (udev_device->syspath ==  NULL)
1584                 return -ENOMEM;
1585         udev_device->devpath = udev_device->syspath + strlen("/sys");
1586         udev_device_add_property(udev_device, "DEVPATH", udev_device->devpath);
1587
1588         pos = strrchr(udev_device->syspath, '/');
1589         if (pos == NULL)
1590                 return -EINVAL;
1591         udev_device->sysname = strdup(&pos[1]);
1592         if (udev_device->sysname == NULL)
1593                 return -ENOMEM;
1594
1595         /* some devices have '!' in their name, change that to '/' */
1596         len = 0;
1597         while (udev_device->sysname[len] != '\0') {
1598                 if (udev_device->sysname[len] == '!')
1599                         udev_device->sysname[len] = '/';
1600                 len++;
1601         }
1602
1603         /* trailing number */
1604         while (len > 0 && isdigit(udev_device->sysname[--len]))
1605                 udev_device->sysnum = &udev_device->sysname[len];
1606
1607         /* sysname is completely numeric */
1608         if (len == 0)
1609                 udev_device->sysnum = NULL;
1610
1611         return 0;
1612 }
1613
1614 static int udev_device_set_devnode(struct udev_device *udev_device, const char *devnode)
1615 {
1616         free(udev_device->devnode);
1617         if (devnode[0] != '/') {
1618                 if (asprintf(&udev_device->devnode, "/dev/%s", devnode) < 0)
1619                         udev_device->devnode = NULL;
1620         } else {
1621                 udev_device->devnode = strdup(devnode);
1622         }
1623         if (udev_device->devnode == NULL)
1624                 return -ENOMEM;
1625         udev_device_add_property(udev_device, "DEVNAME", udev_device->devnode);
1626         return 0;
1627 }
1628
1629 int udev_device_add_devlink(struct udev_device *udev_device, const char *devlink)
1630 {
1631         struct udev_list_entry *list_entry;
1632
1633         udev_device->devlinks_uptodate = false;
1634         list_entry = udev_list_entry_add(&udev_device->devlinks_list, devlink, NULL);
1635         if (list_entry == NULL)
1636                 return -ENOMEM;
1637         return 0;
1638 }
1639
1640 const char *udev_device_get_id_filename(struct udev_device *udev_device)
1641 {
1642         if (udev_device->id_filename == NULL) {
1643                 if (udev_device_get_subsystem(udev_device) == NULL)
1644                         return NULL;
1645
1646                 if (major(udev_device_get_devnum(udev_device)) > 0) {
1647                         /* use dev_t -- b259:131072, c254:0 */
1648                         if (asprintf(&udev_device->id_filename, "%c%u:%u",
1649                                      streq(udev_device_get_subsystem(udev_device), "block") ? 'b' : 'c',
1650                                      major(udev_device_get_devnum(udev_device)),
1651                                      minor(udev_device_get_devnum(udev_device))) < 0)
1652                                 udev_device->id_filename = NULL;
1653                 } else if (udev_device_get_ifindex(udev_device) > 0) {
1654                         /* use netdev ifindex -- n3 */
1655                         if (asprintf(&udev_device->id_filename, "n%u", udev_device_get_ifindex(udev_device)) < 0)
1656                                 udev_device->id_filename = NULL;
1657                 } else {
1658                         /*
1659                          * use $subsys:$syname -- pci:0000:00:1f.2
1660                          * sysname() has '!' translated, get it from devpath
1661                          */
1662                         const char *sysname;
1663                         sysname = strrchr(udev_device->devpath, '/');
1664                         if (sysname == NULL)
1665                                 return NULL;
1666                         sysname = &sysname[1];
1667                         if (asprintf(&udev_device->id_filename, "+%s:%s", udev_device_get_subsystem(udev_device), sysname) < 0)
1668                                 udev_device->id_filename = NULL;
1669                 }
1670         }
1671         return udev_device->id_filename;
1672 }
1673
1674 /**
1675  * udev_device_get_is_initialized:
1676  * @udev_device: udev device
1677  *
1678  * Check if udev has already handled the device and has set up
1679  * device node permissions and context, or has renamed a network
1680  * device.
1681  *
1682  * This is only implemented for devices with a device node
1683  * or network interfaces. All other devices return 1 here.
1684  *
1685  * Returns: 1 if the device is set up. 0 otherwise.
1686  **/
1687 _public_ int udev_device_get_is_initialized(struct udev_device *udev_device)
1688 {
1689         if (!udev_device->info_loaded)
1690                 udev_device_read_db(udev_device, NULL);
1691         return udev_device->is_initialized;
1692 }
1693
1694 void udev_device_set_is_initialized(struct udev_device *udev_device)
1695 {
1696         udev_device->is_initialized = true;
1697 }
1698
1699 int udev_device_add_tag(struct udev_device *udev_device, const char *tag)
1700 {
1701         if (strchr(tag, ':') != NULL || strchr(tag, ' ') != NULL)
1702                 return -EINVAL;
1703         udev_device->tags_uptodate = false;
1704         if (udev_list_entry_add(&udev_device->tags_list, tag, NULL) != NULL)
1705                 return 0;
1706         return -ENOMEM;
1707 }
1708
1709 void udev_device_cleanup_tags_list(struct udev_device *udev_device)
1710 {
1711         udev_device->tags_uptodate = false;
1712         udev_list_cleanup(&udev_device->tags_list);
1713 }
1714
1715 /**
1716  * udev_device_get_tags_list_entry:
1717  * @udev_device: udev device
1718  *
1719  * Retrieve the list of tags attached to the udev device. The next
1720  * list entry can be retrieved with udev_list_entry_get_next(),
1721  * which returns #NULL if no more entries exist. The tag string
1722  * can be retrieved from the list entry by udev_list_entry_get_name().
1723  *
1724  * Returns: the first entry of the tag list
1725  **/
1726 _public_ struct udev_list_entry *udev_device_get_tags_list_entry(struct udev_device *udev_device)
1727 {
1728         if (udev_device == NULL)
1729                 return NULL;
1730         if (!udev_device->info_loaded)
1731                 udev_device_read_db(udev_device, NULL);
1732         return udev_list_get_entry(&udev_device->tags_list);
1733 }
1734
1735 /**
1736  * udev_device_has_tag:
1737  * @udev_device: udev device
1738  * @tag: tag name
1739  *
1740  * Check if a given device has a certain tag associated.
1741  *
1742  * Returns: 1 if the tag is found. 0 otherwise.
1743  **/
1744 _public_ int udev_device_has_tag(struct udev_device *udev_device, const char *tag)
1745 {
1746         struct udev_list_entry *list_entry;
1747
1748         if (udev_device == NULL)
1749                 return false;
1750         if (!udev_device->info_loaded)
1751                 udev_device_read_db(udev_device, NULL);
1752         list_entry = udev_device_get_tags_list_entry(udev_device);
1753         if (udev_list_entry_get_by_name(list_entry, tag) != NULL)
1754                 return true;
1755         return false;
1756 }
1757
1758 #define ENVP_SIZE                        128
1759 #define MONITOR_BUF_SIZE                4096
1760 static int update_envp_monitor_buf(struct udev_device *udev_device)
1761 {
1762         struct udev_list_entry *list_entry;
1763         char *s;
1764         size_t l;
1765         unsigned int i;
1766
1767         /* monitor buffer of property strings */
1768         free(udev_device->monitor_buf);
1769         udev_device->monitor_buf_len = 0;
1770         udev_device->monitor_buf = malloc(MONITOR_BUF_SIZE);
1771         if (udev_device->monitor_buf == NULL)
1772                 return -ENOMEM;
1773
1774         /* envp array, strings will point into monitor buffer */
1775         if (udev_device->envp == NULL)
1776                 udev_device->envp = malloc(sizeof(char *) * ENVP_SIZE);
1777         if (udev_device->envp == NULL)
1778                 return -ENOMEM;
1779
1780         i = 0;
1781         s = udev_device->monitor_buf;
1782         l = MONITOR_BUF_SIZE;
1783         udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device)) {
1784                 const char *key;
1785
1786                 key = udev_list_entry_get_name(list_entry);
1787                 /* skip private variables */
1788                 if (key[0] == '.')
1789                         continue;
1790
1791                 /* add string to envp array */
1792                 udev_device->envp[i++] = s;
1793                 if (i+1 >= ENVP_SIZE)
1794                         return -EINVAL;
1795
1796                 /* add property string to monitor buffer */
1797                 l = strpcpyl(&s, l, key, "=", udev_list_entry_get_value(list_entry), NULL);
1798                 if (l == 0)
1799                         return -EINVAL;
1800                 /* advance past the trailing '\0' that strpcpyl() guarantees */
1801                 s++;
1802                 l--;
1803         }
1804         udev_device->envp[i] = NULL;
1805         udev_device->monitor_buf_len = s - udev_device->monitor_buf;
1806         udev_device->envp_uptodate = true;
1807         return 0;
1808 }
1809
1810 char **udev_device_get_properties_envp(struct udev_device *udev_device)
1811 {
1812         if (!udev_device->envp_uptodate)
1813                 if (update_envp_monitor_buf(udev_device) != 0)
1814                         return NULL;
1815         return udev_device->envp;
1816 }
1817
1818 ssize_t udev_device_get_properties_monitor_buf(struct udev_device *udev_device, const char **buf)
1819 {
1820         if (!udev_device->envp_uptodate)
1821                 if (update_envp_monitor_buf(udev_device) != 0)
1822                         return -EINVAL;
1823         *buf = udev_device->monitor_buf;
1824         return udev_device->monitor_buf_len;
1825 }
1826
1827 int udev_device_set_action(struct udev_device *udev_device, const char *action)
1828 {
1829         free(udev_device->action);
1830         udev_device->action = strdup(action);
1831         if (udev_device->action == NULL)
1832                 return -ENOMEM;
1833         udev_device_add_property(udev_device, "ACTION", udev_device->action);
1834         return 0;
1835 }
1836
1837 int udev_device_get_devlink_priority(struct udev_device *udev_device)
1838 {
1839         if (!udev_device->info_loaded)
1840                 udev_device_read_db(udev_device, NULL);
1841         return udev_device->devlink_priority;
1842 }
1843
1844 int udev_device_set_devlink_priority(struct udev_device *udev_device, int prio)
1845 {
1846          udev_device->devlink_priority = prio;
1847         return 0;
1848 }
1849
1850 int udev_device_get_watch_handle(struct udev_device *udev_device)
1851 {
1852         if (!udev_device->info_loaded)
1853                 udev_device_read_db(udev_device, NULL);
1854         return udev_device->watch_handle;
1855 }
1856
1857 int udev_device_set_watch_handle(struct udev_device *udev_device, int handle)
1858 {
1859         udev_device->watch_handle = handle;
1860         return 0;
1861 }
1862
1863 bool udev_device_get_db_persist(struct udev_device *udev_device)
1864 {
1865         return udev_device->db_persist;
1866 }
1867
1868 void udev_device_set_db_persist(struct udev_device *udev_device)
1869 {
1870         udev_device->db_persist = true;
1871 }