summaryrefslogtreecommitdiff
path: root/LICENSES/CC0-1.0.txt
blob: a343ccd4335f66ace3f9a83dfff02212a84ef4f2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
Creative Commons Legal Code

CC0 1.0 Universal CREATIVE COMMONS CORPORATION IS NOT A LAW FIRM AND DOES
NOT PROVIDE LEGAL SERVICES. DISTRIBUTION OF THIS DOCUMENT DOES NOT CREATE
AN ATTORNEY-CLIENT RELATIONSHIP. CREATIVE COMMONS PROVIDES THIS INFORMATION
ON AN "AS-IS" BASIS. CREATIVE COMMONS MAKES NO WARRANTIES REGARDING THE USE
OF THIS DOCUMENT OR THE INFORMATION OR WORKS PROVIDED HEREUNDER, AND DISCLAIMS
LIABILITY FOR DAMAGES RESULTING FROM THE USE OF THIS DOCUMENT OR THE INFORMATION
OR WORKS PROVIDED HEREUNDER.

Statement of Purpose

The laws of most jurisdictions throughout the world automatically confer exclusive
Copyright and Related Rights (defined below) upon the creator and subsequent
owner(s) (each and all, an "owner") of an original work of authorship and/or
a database (each, a "Work").

Certain owners wish to permanently relinquish those rights to a Work for the
purpose of contributing to a commons of creative, cultural and scientific
works ("Commons") that the public can reliably and without fear of later claims
of infringement build upon, modify, incorporate in other works, reuse and
redistribute as freely as possible in any form whatsoever and for any purposes,
including without limitation commercial purposes. These owners may contribute
to the Commons to promote the ideal of a free culture and the further production
of creative, cultural and scientific works, or to gain reputation or greater
distribution for their Work in part through the use and efforts of others.

For these and/or other purposes and motivations, and without any expectation
of additional consideration or compensation, the person associating CC0 with
a Work (the "Affirmer"), to the extent that he or she is an owner of Copyright
and Related Rights in the Work, voluntarily elects to apply CC0 to the Work
and publicly distribute the Work under its terms, with knowledge of his or
her Copyright and Related Rights in the Work and the meaning and intended
legal effect of CC0 on those rights.

1. Copyright and Related Rights. A Work made available under CC0 may be protected
by copyright and related or neighboring rights ("Copyright and Related Rights").
Copyright and Related Rights include, but are not limited to, the following:

i. the right to reproduce, adapt, distribute, perform, display, communicate,
and translate a Work;

      ii. moral rights retained by the original author(s) and/or performer(s);

iii. publicity and privacy rights pertaining to a person's image or likeness
depicted in a Work;

iv. rights protecting against unfair competition in regards to a Work, subject
to the limitations in paragraph 4(a), below;

v. rights protecting the extraction, dissemination, use and reuse of data
in a Work;

vi. database rights (such as those arising under Directive 96/9/EC of the
European Parliament and of the Council of 11 March 1996 on the legal protection
of databases, and under any national implementation thereof, including any
amended or successor version of such directive); and

vii. other similar, equivalent or corresponding rights throughout the world
based on applicable law or treaty, and any national implementations thereof.

2. Waiver. To the greatest extent permitted by, but not in contravention of,
applicable law, Affirmer hereby overtly, fully, permanently, irrevocably and
unconditionally waives, abandons, and surrenders all of Affirmer's Copyright
and Related Rights and associated claims and causes of action, whether now
known or unknown (including existing as well as future claims and causes of
action), in the Work (i) in all territories worldwide, (ii) for the maximum
duration provided by applicable law or treaty (including future time extensions),
(iii) in any current or future medium and for any number of copies, and (iv)
for any purpose whatsoever, including without limitation commercial, advertising
or promotional purposes (the "Waiver"). Affirmer makes the Waiver for the
benefit of each member of the public at large and to the detriment of Affirmer's
heirs and successors, fully intending that such Waiver shall not be subject
to revocation, rescission, cancellation, termination, or any other legal or
equitable action to disrupt the quiet enjoyment of the Work by the public
as contemplated by Affirmer's express Statement of Purpose.

3. Public License Fallback. Should any part of the Waiver for any reason be
judged legally invalid or ineffective under applicable law, then the Waiver
shall be preserved to the maximum extent permitted taking into account Affirmer's
express Statement of Purpose. In addition, to the extent the Waiver is so
judged Affirmer hereby grants to each affected person a royalty-free, non
transferable, non sublicensable, non exclusive, irrevocable and unconditional
license to exercise Affirmer's Copyright and Related Rights in the Work (i)
in all territories worldwide, (ii) for the maximum duration provided by applicable
law or treaty (including future time extensions), (iii) in any current or
future medium and for any number of copies, and (iv) for any purpose whatsoever,
including without limitation commercial, advertising or promotional purposes
(the "License"). The License shall be deemed effective as of the date CC0
was applied by Affirmer to the Work. Should any part of the License for any
reason be judged legally invalid or ineffective under applicable law, such
partial invalidity or ineffectiveness shall not invalidate the remainder of
the License, and in such case Affirmer hereby affirms that he or she will
not (i) exercise any of his or her remaining Copyright and Related Rights
in the Work or (ii) assert any associated claims and causes of action with
respect to the Work, in either case contrary to Affirmer's express Statement
of Purpose.

   4. Limitations and Disclaimers.

a. No trademark or patent rights held by Affirmer are waived, abandoned, surrendered,
licensed or otherwise affected by this document.

b. Affirmer offers the Work as-is and makes no representations or warranties
of any kind concerning the Work, express, implied, statutory or otherwise,
including without limitation warranties of title, merchantability, fitness
for a particular purpose, non infringement, or the absence of latent or other
defects, accuracy, or the present or absence of errors, whether or not discoverable,
all to the greatest extent permissible under applicable law.

c. Affirmer disclaims responsibility for clearing rights of other persons
that may apply to the Work or any use thereof, including without limitation
any person's Copyright and Related Rights in the Work. Further, Affirmer disclaims
responsibility for obtaining any necessary consents, permissions or other
rights required for any use of the Work.

d. Affirmer understands and acknowledges that Creative Commons is not a party
to this document and has no duty or obligation with respect to this CC0 or
use of the Work.
f='#n273'>273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322
/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2018, Google Inc.
 *
 * device_enumerator.cpp - Enumeration and matching
 */

#include "libcamera/internal/device_enumerator.h"

#include <string.h>

#include <libcamera/base/log.h>

#include "libcamera/internal/device_enumerator_sysfs.h"
#include "libcamera/internal/device_enumerator_udev.h"
#include "libcamera/internal/media_device.h"

/**
 * \file device_enumerator.h
 * \brief Enumeration and matching of media devices
 *
 * The purpose of device enumeration and matching is to find media devices in
 * the system and map them to pipeline handlers.
 *
 * At the core of the enumeration is the DeviceEnumerator class, responsible
 * for enumerating all media devices in the system. It handles all interactions
 * with the operating system in a platform-specific way. For each media device
 * found an instance of MediaDevice is created to store information about the
 * device gathered from the kernel through the Media Controller API.
 *
 * The DeviceEnumerator can enumerate all or specific media devices in the
 * system. When a new media device is added the enumerator creates a
 * corresponding MediaDevice instance.
 *
 * The enumerator supports searching among enumerated devices based on criteria
 * expressed in a DeviceMatch object.
 */

namespace libcamera {

LOG_DEFINE_CATEGORY(DeviceEnumerator)

/**
 * \class DeviceMatch
 * \brief Description of a media device search pattern
 *
 * The DeviceMatch class describes a media device using properties from the
 * Media Controller struct media_device_info, entity names in the media graph
 * or other properties that can be used to identify a media device.
 *
 * The description is meant to be filled by pipeline managers and passed to a
 * device enumerator to find matching media devices.
 *
 * A DeviceMatch is created with a specific Linux device driver in mind,
 * therefore the name of the driver is a required property. One or more Entity
 * names can be added as match criteria.
 *
 * Pipeline handlers are recommended to add entities to DeviceMatch as
 * appropriare to ensure that the media device they need can be uniquely
 * identified. This is useful when the corresponding kernel driver can produce
 * different graphs, for instance as a result of different driver versions or
 * hardware configurations, and not all those graphs are suitable for a pipeline
 * handler.
 */

/**
 * \brief Construct a media device search pattern
 * \param[in] driver The Linux device driver name that created the media device
 */
DeviceMatch::DeviceMatch(const std::string &driver)
	: driver_(driver)
{
}

/**
 * \brief Add a media entity name to the search pattern
 * \param[in] entity The name of the entity in the media graph
 */
void DeviceMatch::add(const std::string &entity)
{
	entities_.push_back(entity);
}

/**
 * \brief Compare a search pattern with a media device
 * \param[in] device The media device
 *
 * Matching is performed on the Linux device driver name and entity names from
 * the media graph. A match is found if both the driver name matches and the
 * media device contains all the entities listed in the search pattern.
 *
 * \return true if the media device matches the search pattern, false otherwise
 */
bool DeviceMatch::match(const MediaDevice *device) const
{
	if (driver_ != device->driver())
		return false;

	for (const std::string &name : entities_) {
		bool found = false;

		for (const MediaEntity *entity : device->entities()) {
			if (name == entity->name()) {
				found = true;
				break;
			}
		}

		if (!found)
			return false;
	}

	return true;
}

/**
 * \class DeviceEnumerator
 * \brief Enumerate, store and search media devices
 *
 * The DeviceEnumerator class is responsible for all interactions with the
 * operating system related to media devices. It enumerates all media devices
 * in the system, and for each device found creates an instance of the
 * MediaDevice class and stores it internally. The list of media devices can
 * then be searched using DeviceMatch search patterns.
 *
 * The enumerator also associates media device entities with device node paths.
 */

/**
 * \brief Create a new device enumerator matching the systems capabilities
 *
 * Depending on how the operating system handles device detection, hot-plug
 * notification and device node lookup, different device enumerator
 * implementations may be needed. This function creates the best enumerator for
 * the operating system based on the available resources. Not all different
 * enumerator types are guaranteed to support all features.
 *
 * \return A pointer to the newly created device enumerator on success, or
 * nullptr if an error occurs
 */
std::unique_ptr<DeviceEnumerator> DeviceEnumerator::create()
{
	std::unique_ptr<DeviceEnumerator> enumerator;

#ifdef HAVE_LIBUDEV
	enumerator = std::make_unique<DeviceEnumeratorUdev>();
	if (!enumerator->init())
		return enumerator;
#endif

	/*
	 * Either udev is not available or udev initialization failed. Fall back
	 * on the sysfs enumerator.
	 */
	enumerator = std::make_unique<DeviceEnumeratorSysfs>();
	if (!enumerator->init())
		return enumerator;

	return nullptr;
}

DeviceEnumerator::~DeviceEnumerator()
{
	for (std::shared_ptr<MediaDevice> media : devices_) {
		if (media->busy())
			LOG(DeviceEnumerator, Error)
				<< "Removing media device " << media->deviceNode()
				<< " while still in use";
	}
}

/**
 * \fn DeviceEnumerator::init()
 * \brief Initialize the enumerator
 * \return 0 on success or a negative error code otherwise
 * \retval -EBUSY the enumerator has already been initialized
 * \retval -ENODEV the enumerator can't enumerate devices
 */

/**
 * \fn DeviceEnumerator::enumerate()
 * \brief Enumerate all media devices in the system
 *
 * This function finds and add all media devices in the system to the
 * enumerator. It shall be implemented by all subclasses of DeviceEnumerator
 * using system-specific methods.
 *
 * Individual media devices that can't be properly enumerated shall be skipped
 * with a warning message logged, without returning an error. Only errors that
 * prevent enumeration altogether shall be fatal.
 *
 * \context This function is \threadbound.
 *
 * \return 0 on success or a negative error code otherwise
 */

/**
 * \brief Create a media device instance
 * \param[in] deviceNode path to the media device to create
 *
 * Create a media device for the \a deviceNode, open it, and populate its
 * media graph. The device enumerator shall then populate the media device by
 * associating device nodes with entities using MediaEntity::setDeviceNode().
 * This process is specific to each device enumerator, and the device enumerator
 * shall ensure that device nodes are ready to be used (for instance, if