src/libudev/libudev-enumerate.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include <dirent.h>
   4 #include <errno.h>
   5 #include <fnmatch.h>
   6 #include <stdbool.h>
   7 #include <stddef.h>
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include <string.h>
  11 #include <sys/stat.h>
  12
  13 #include "libudev.h"
  14 #include "sd-device.h"
  15
  16 #include "alloc-util.h"
  17 #include "device-enumerator-private.h"
  18 #include "device-util.h"
  19 #include "libudev-device-internal.h"
  20
  21 /**
  22  * SECTION:libudev-enumerate
  23  * @short_description: lookup and sort sys devices
  24  *
  25  * Lookup devices in the sys filesystem, filter devices by properties,
  26  * and return a sorted list of devices.
  27  */
  28
  29 /**
  30  * udev_enumerate:
  31  *
  32  * Opaque object representing one device lookup/sort context.
  33  */
  34 struct udev_enumerate {
  35         struct udev *udev;
  36         unsigned n_ref;
  37         struct udev_list *devices_list;
  38         bool devices_uptodate:1;
  39
  40         sd_device_enumerator *enumerator;
  41 };
  42
  43 /**
  44  * udev_enumerate_new:
  45  * @udev: udev library context
  46  *
  47  * Create an enumeration context to scan /sys.
  48  *
  49  * Returns: an enumeration context.
  50  **/
  51 _public_ struct udev_enumerate *udev_enumerate_new(struct udev *udev) {
  52         _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
  53         _cleanup_(udev_list_freep) struct udev_list *list = NULL;
  54         struct udev_enumerate *udev_enumerate;
  55         int r;
  56
  57         r = sd_device_enumerator_new(&e);
  58         if (r < 0)
  59                 return_with_errno(NULL, r);
  60
  61         r = sd_device_enumerator_allow_uninitialized(e);
  62         if (r < 0)
  63                 return_with_errno(NULL, r);
  64
  65         list = udev_list_new(false);
  66         if (!list)
  67                 return_with_errno(NULL, ENOMEM);
  68
  69         udev_enumerate = new(struct udev_enumerate, 1);
  70         if (!udev_enumerate)
  71                 return_with_errno(NULL, ENOMEM);
  72
  73         *udev_enumerate = (struct udev_enumerate) {
  74                 .udev = udev,
  75                 .n_ref = 1,
  76                 .enumerator = TAKE_PTR(e),
  77                 .devices_list = TAKE_PTR(list),
  78         };
  79
  80         return udev_enumerate;
  81 }
  82
  83 static struct udev_enumerate *udev_enumerate_free(struct udev_enumerate *udev_enumerate) {
  84         assert(udev_enumerate);
  85
  86         udev_list_free(udev_enumerate->devices_list);
  87         sd_device_enumerator_unref(udev_enumerate->enumerator);
  88         return mfree(udev_enumerate);
  89 }
  90
  91 /**
  92  * udev_enumerate_ref:
  93  * @udev_enumerate: context
  94  *
  95  * Take a reference of a enumeration context.
  96  *
  97  * Returns: the passed enumeration context
  98  **/
  99
 100 /**
 101  * udev_enumerate_unref:
 102  * @udev_enumerate: context
 103  *
 104  * Drop a reference of an enumeration context. If the refcount reaches zero,
 105  * all resources of the enumeration context will be released.
 106  *
 107  * Returns: #NULL
 108  **/
 109 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(struct udev_enumerate, udev_enumerate, udev_enumerate_free);
 110
 111 /**
 112  * udev_enumerate_get_udev:
 113  * @udev_enumerate: context
 114  *
 115  * Get the udev library context.
 116  *
 117  * Returns: a pointer to the context.
 118  */
 119 _public_ struct udev *udev_enumerate_get_udev(struct udev_enumerate *udev_enumerate) {
 120         assert_return_errno(udev_enumerate, NULL, EINVAL);
 121
 122         return udev_enumerate->udev;
 123 }
 124
 125 /**
 126  * udev_enumerate_get_list_entry:
 127  * @udev_enumerate: context
 128  *
 129  * Get the first entry of the sorted list of device paths.
 130  *
 131  * Returns: a udev_list_entry.
 132  */
 133 _public_ struct udev_list_entry *udev_enumerate_get_list_entry(struct udev_enumerate *udev_enumerate) {
 134         struct udev_list_entry *e;
 135
 136         assert_return_errno(udev_enumerate, NULL, EINVAL);
 137
 138         if (!udev_enumerate->devices_uptodate) {
 139                 sd_device *device;
 140
 141                 udev_list_cleanup(udev_enumerate->devices_list);
 142
 143                 FOREACH_DEVICE_AND_SUBSYSTEM(udev_enumerate->enumerator, device) {
 144                         const char *syspath;
 145                         int r;
 146
 147                         r = sd_device_get_syspath(device, &syspath);
 148                         if (r < 0)
 149                                 return_with_errno(NULL, r);
 150
 151                         if (!udev_list_entry_add(udev_enumerate->devices_list, syspath, NULL))
 152                                 return_with_errno(NULL, ENOMEM);
 153                 }
 154
 155                 udev_enumerate->devices_uptodate = true;
 156         }
 157
 158         e = udev_list_get_entry(udev_enumerate->devices_list);
 159         if (!e)
 160                 return_with_errno(NULL, ENODATA);
 161
 162         return e;
 163 }
 164
 165 /**
 166  * udev_enumerate_add_match_subsystem:
 167  * @udev_enumerate: context
 168  * @subsystem: filter for a subsystem of the device to include in the list
 169  *
 170  * Match only devices belonging to a certain kernel subsystem.
 171  *
 172  * Returns: 0 on success, otherwise a negative error value.
 173  */
 174 _public_ int udev_enumerate_add_match_subsystem(struct udev_enumerate *udev_enumerate, const char *subsystem) {
 175         assert_return(udev_enumerate, -EINVAL);
 176
 177         if (!subsystem)
 178                 return 0;
 179
 180         return sd_device_enumerator_add_match_subsystem(udev_enumerate->enumerator, subsystem, true);
 181 }
 182
 183 /**
 184  * udev_enumerate_add_nomatch_subsystem:
 185  * @udev_enumerate: context
 186  * @subsystem: filter for a subsystem of the device to exclude from the list
 187  *
 188  * Match only devices not belonging to a certain kernel subsystem.
 189  *
 190  * Returns: 0 on success, otherwise a negative error value.
 191  */
 192 _public_ int udev_enumerate_add_nomatch_subsystem(struct udev_enumerate *udev_enumerate, const char *subsystem) {
 193         assert_return(udev_enumerate, -EINVAL);
 194
 195         if (!subsystem)
 196                 return 0;
 197
 198         return sd_device_enumerator_add_match_subsystem(udev_enumerate->enumerator, subsystem, false);
 199 }
 200
 201 /**
 202  * udev_enumerate_add_match_sysattr:
 203  * @udev_enumerate: context
 204  * @sysattr: filter for a sys attribute at the device to include in the list
 205  * @value: optional value of the sys attribute
 206  *
 207  * Match only devices with a certain /sys device attribute.
 208  *
 209  * Returns: 0 on success, otherwise a negative error value.
 210  */
 211 _public_ int udev_enumerate_add_match_sysattr(struct udev_enumerate *udev_enumerate, const char *sysattr, const char *value) {
 212         assert_return(udev_enumerate, -EINVAL);
 213
 214         if (!sysattr)
 215                 return 0;
 216
 217         return sd_device_enumerator_add_match_sysattr(udev_enumerate->enumerator, sysattr, value, true);
 218 }
 219
 220 /**
 221  * udev_enumerate_add_nomatch_sysattr:
 222  * @udev_enumerate: context
 223  * @sysattr: filter for a sys attribute at the device to exclude from the list
 224  * @value: optional value of the sys attribute
 225  *
 226  * Match only devices not having a certain /sys device attribute.
 227  *
 228  * Returns: 0 on success, otherwise a negative error value.
 229  */
 230 _public_ int udev_enumerate_add_nomatch_sysattr(struct udev_enumerate *udev_enumerate, const char *sysattr, const char *value) {
 231         assert_return(udev_enumerate, -EINVAL);
 232
 233         if (!sysattr)
 234                 return 0;
 235
 236         return sd_device_enumerator_add_match_sysattr(udev_enumerate->enumerator, sysattr, value, false);
 237 }
 238
 239 /**
 240  * udev_enumerate_add_match_property:
 241  * @udev_enumerate: context
 242  * @property: filter for a property of the device to include in the list
 243  * @value: value of the property
 244  *
 245  * Match only devices with a certain property.
 246  *
 247  * Returns: 0 on success, otherwise a negative error value.
 248  */
 249 _public_ int udev_enumerate_add_match_property(struct udev_enumerate *udev_enumerate, const char *property, const char *value) {
 250         assert_return(udev_enumerate, -EINVAL);
 251
 252         if (!property)
 253                 return 0;
 254
 255         return sd_device_enumerator_add_match_property(udev_enumerate->enumerator, property, value);
 256 }
 257
 258 /**
 259  * udev_enumerate_add_match_tag:
 260  * @udev_enumerate: context
 261  * @tag: filter for a tag of the device to include in the list
 262  *
 263  * Match only devices with a certain tag.
 264  *
 265  * Returns: 0 on success, otherwise a negative error value.
 266  */
 267 _public_ int udev_enumerate_add_match_tag(struct udev_enumerate *udev_enumerate, const char *tag) {
 268         assert_return(udev_enumerate, -EINVAL);
 269
 270         if (!tag)
 271                 return 0;
 272
 273         return sd_device_enumerator_add_match_tag(udev_enumerate->enumerator, tag);
 274 }
 275
 276 /**
 277  * udev_enumerate_add_match_parent:
 278  * @udev_enumerate: context
 279  * @parent: parent device where to start searching
 280  *
 281  * Return the devices on the subtree of one given device. The parent
 282  * itself is included in the list.
 283  *
 284  * Returns: 0 on success, otherwise a negative error value.
 285  */
 286 _public_ int udev_enumerate_add_match_parent(struct udev_enumerate *udev_enumerate, struct udev_device *parent) {
 287         assert_return(udev_enumerate, -EINVAL);
 288
 289         if (!parent)
 290                 return 0;
 291
 292         return sd_device_enumerator_add_match_parent(udev_enumerate->enumerator, parent->device);
 293 }
 294
 295 /**
 296  * udev_enumerate_add_match_is_initialized:
 297  * @udev_enumerate: context
 298  *
 299  * Match only devices which udev has set up already. This makes
 300  * sure, that the device node permissions and context are properly set
 301  * and that network devices are fully renamed.
 302  *
 303  * Usually, devices which are found in the kernel but not already
 304  * handled by udev, have still pending events. Services should subscribe
 305  * to monitor events and wait for these devices to become ready, instead
 306  * of using uninitialized devices.
 307  *
 308  * For now, this will not affect devices which do not have a device node
 309  * and are not network interfaces.
 310  *
 311  * Returns: 0 on success, otherwise a negative error value.
 312  */
 313 _public_ int udev_enumerate_add_match_is_initialized(struct udev_enumerate *udev_enumerate) {
 314         assert_return(udev_enumerate, -EINVAL);
 315
 316         return device_enumerator_add_match_is_initialized(udev_enumerate->enumerator);
 317 }
 318
 319 /**
 320  * udev_enumerate_add_match_sysname:
 321  * @udev_enumerate: context
 322  * @sysname: filter for the name of the device to include in the list
 323  *
 324  * Match only devices with a given /sys device name.
 325  *
 326  * Returns: 0 on success, otherwise a negative error value.
 327  */
 328 _public_ int udev_enumerate_add_match_sysname(struct udev_enumerate *udev_enumerate, const char *sysname) {
 329         assert_return(udev_enumerate, -EINVAL);
 330
 331         if (!sysname)
 332                 return 0;
 333
 334         return sd_device_enumerator_add_match_sysname(udev_enumerate->enumerator, sysname);
 335 }
 336
 337 /**
 338  * udev_enumerate_add_syspath:
 339  * @udev_enumerate: context
 340  * @syspath: path of a device
 341  *
 342  * Add a device to the list of devices, to retrieve it back sorted in dependency order.
 343  *
 344  * Returns: 0 on success, otherwise a negative error value.
 345  */
 346 _public_ int udev_enumerate_add_syspath(struct udev_enumerate *udev_enumerate, const char *syspath) {
 347         _cleanup_(sd_device_unrefp) sd_device *device = NULL;
 348         int r;
 349
 350         assert_return(udev_enumerate, -EINVAL);
 351
 352         if (!syspath)
 353                 return 0;
 354
 355         r = sd_device_new_from_syspath(&device, syspath);
 356         if (r < 0)
 357                 return r;
 358
 359         r = device_enumerator_add_device(udev_enumerate->enumerator, device);
 360         if (r < 0)
 361                 return r;
 362
 363         return 0;
 364 }
 365
 366 /**
 367  * udev_enumerate_scan_devices:
 368  * @udev_enumerate: udev enumeration context
 369  *
 370  * Scan /sys for all devices which match the given filters. No matches
 371  * will return all currently available devices.
 372  *
 373  * Returns: 0 on success, otherwise a negative error value.
 374  **/
 375 _public_ int udev_enumerate_scan_devices(struct udev_enumerate *udev_enumerate) {
 376         assert_return(udev_enumerate, -EINVAL);
 377
 378         return device_enumerator_scan_devices(udev_enumerate->enumerator);
 379 }
 380
 381 /**
 382  * udev_enumerate_scan_subsystems:
 383  * @udev_enumerate: udev enumeration context
 384  *
 385  * Scan /sys for all kernel subsystems, including buses, classes, drivers.
 386  *
 387  * Returns: 0 on success, otherwise a negative error value.
 388  **/
 389 _public_ int udev_enumerate_scan_subsystems(struct udev_enumerate *udev_enumerate) {
 390         assert_return(udev_enumerate, -EINVAL);
 391
 392         return device_enumerator_scan_subsystems(udev_enumerate->enumerator);
 393 }