Line data    Source code

       1             : /***
       2             :   This file is part of systemd.
       3             : 
       4             :   Copyright Tom Gundersen <teg@jklm.no>
       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 "libudev-private.h"
      21             : #include "sd-hwdb.h"
      22             : #include "hwdb-util.h"
      23             : 
      24             : /**
      25             :  * SECTION:libudev-hwdb
      26             :  * @short_description: retrieve properties from the hardware database
      27             :  *
      28             :  * Libudev hardware database interface.
      29             :  */
      30             : 
      31             : /**
      32             :  * udev_hwdb:
      33             :  *
      34             :  * Opaque object representing the hardware database.
      35             :  */
      36             : struct udev_hwdb {
      37             :         struct udev *udev;
      38             :         int refcount;
      39             : 
      40             :         sd_hwdb *hwdb;
      41             : 
      42             :         struct udev_list properties_list;
      43             : };
      44             : 
      45             : /**
      46             :  * udev_hwdb_new:
      47             :  * @udev: udev library context
      48             :  *
      49             :  * Create a hardware database context to query properties for devices.
      50             :  *
      51             :  * Returns: a hwdb context.
      52             :  **/
      53           0 : _public_ struct udev_hwdb *udev_hwdb_new(struct udev *udev) {
      54           0 :         _cleanup_hwdb_unref_ sd_hwdb *hwdb_internal = NULL;
      55             :         struct udev_hwdb *hwdb;
      56             :         int r;
      57             : 
      58           0 :         assert_return(udev, NULL);
      59             : 
      60           0 :         r = sd_hwdb_new(&hwdb_internal);
      61           0 :         if (r < 0)
      62           0 :                 return NULL;
      63             : 
      64           0 :         hwdb = new0(struct udev_hwdb, 1);
      65           0 :         if (!hwdb)
      66           0 :                 return NULL;
      67             : 
      68           0 :         hwdb->refcount = 1;
      69           0 :         hwdb->hwdb = hwdb_internal;
      70           0 :         hwdb_internal = NULL;
      71             : 
      72           0 :         udev_list_init(udev, &hwdb->properties_list, true);
      73             : 
      74           0 :         return hwdb;
      75             : }
      76             : 
      77             : /**
      78             :  * udev_hwdb_ref:
      79             :  * @hwdb: context
      80             :  *
      81             :  * Take a reference of a hwdb context.
      82             :  *
      83             :  * Returns: the passed enumeration context
      84             :  **/
      85           0 : _public_ struct udev_hwdb *udev_hwdb_ref(struct udev_hwdb *hwdb) {
      86           0 :         if (!hwdb)
      87           0 :                 return NULL;
      88           0 :         hwdb->refcount++;
      89           0 :         return hwdb;
      90             : }
      91             : 
      92             : /**
      93             :  * udev_hwdb_unref:
      94             :  * @hwdb: context
      95             :  *
      96             :  * Drop a reference of a hwdb context. If the refcount reaches zero,
      97             :  * all resources of the hwdb context will be released.
      98             :  *
      99             :  * Returns: #NULL
     100             :  **/
     101           0 : _public_ struct udev_hwdb *udev_hwdb_unref(struct udev_hwdb *hwdb) {
     102           0 :         if (!hwdb)
     103           0 :                 return NULL;
     104           0 :         hwdb->refcount--;
     105           0 :         if (hwdb->refcount > 0)
     106           0 :                 return NULL;
     107           0 :         sd_hwdb_unref(hwdb->hwdb);
     108           0 :         udev_list_cleanup(&hwdb->properties_list);
     109           0 :         free(hwdb);
     110           0 :         return NULL;
     111             : }
     112             : 
     113             : /**
     114             :  * udev_hwdb_get_properties_list_entry:
     115             :  * @hwdb: context
     116             :  * @modalias: modalias string
     117             :  * @flags: (unused)
     118             :  *
     119             :  * Lookup a matching device in the hardware database. The lookup key is a
     120             :  * modalias string, whose formats are defined for the Linux kernel modules.
     121             :  * Examples are: pci:v00008086d00001C2D*, usb:v04F2pB221*. The first entry
     122             :  * of a list of retrieved properties is returned.
     123             :  *
     124             :  * Returns: a udev_list_entry.
     125             :  */
     126           0 : _public_ struct udev_list_entry *udev_hwdb_get_properties_list_entry(struct udev_hwdb *hwdb, const char *modalias, unsigned int flags) {
     127             :         const char *key, *value;
     128             : 
     129           0 :         if (!hwdb || !modalias) {
     130           0 :                 errno = EINVAL;
     131           0 :                 return NULL;
     132             :         }
     133             : 
     134           0 :         udev_list_cleanup(&hwdb->properties_list);
     135             : 
     136           0 :         SD_HWDB_FOREACH_PROPERTY(hwdb->hwdb, modalias, key, value) {
     137           0 :                 if (udev_list_entry_add(&hwdb->properties_list, key, value) == NULL) {
     138           0 :                         errno = ENOMEM;
     139           0 :                         return NULL;
     140             :                 }
     141             :         }
     142             : 
     143           0 :         return udev_list_get_entry(&hwdb->properties_list);
     144             : }