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1 /*
2  * Copyright (C) 2014 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef ANDROID_INCLUDE_HARDWARE_FINGERPRINT_H
18 #define ANDROID_INCLUDE_HARDWARE_FINGERPRINT_H
19 
20 #include <hardware/hw_auth_token.h>
21 
22 #define FINGERPRINT_MODULE_API_VERSION_1_0 HARDWARE_MODULE_API_VERSION(1, 0)
23 #define FINGERPRINT_MODULE_API_VERSION_2_0 HARDWARE_MODULE_API_VERSION(2, 0)
24 #define FINGERPRINT_HARDWARE_MODULE_ID "fingerprint"
25 
26 typedef enum fingerprint_msg_type {
27     FINGERPRINT_ERROR = -1,
28     FINGERPRINT_ACQUIRED = 1,
29     FINGERPRINT_TEMPLATE_ENROLLING = 3,
30     FINGERPRINT_TEMPLATE_REMOVED = 4,
31     FINGERPRINT_AUTHENTICATED = 5
32 } fingerprint_msg_type_t;
33 
34 /*
35  * Fingerprint errors are meant to tell the framework to terminate the current operation and ask
36  * for the user to correct the situation. These will almost always result in messaging and user
37  * interaction to correct the problem.
38  *
39  * For example, FINGERPRINT_ERROR_CANCELED should follow any acquisition message that results in
40  * a situation where the current operation can't continue without user interaction. For example,
41  * if the sensor is dirty during enrollment and no further enrollment progress can be made,
42  * send FINGERPRINT_ACQUIRED_IMAGER_DIRTY followed by FINGERPRINT_ERROR_CANCELED.
43  */
44 typedef enum fingerprint_error {
45     FINGERPRINT_ERROR_HW_UNAVAILABLE = 1, /* The hardware has an error that can't be resolved. */
46     FINGERPRINT_ERROR_UNABLE_TO_PROCESS = 2, /* Bad data; operation can't continue */
47     FINGERPRINT_ERROR_TIMEOUT = 3, /* The operation has timed out waiting for user input. */
48     FINGERPRINT_ERROR_NO_SPACE = 4, /* No space available to store a template */
49     FINGERPRINT_ERROR_CANCELED = 5, /* The current operation can't proceed. See above. */
50     FINGERPRINT_ERROR_UNABLE_TO_REMOVE = 6, /* fingerprint with given id can't be removed */
51     FINGERPRINT_ERROR_VENDOR_BASE = 1000 /* vendor-specific error messages start here */
52 } fingerprint_error_t;
53 
54 /*
55  * Fingerprint acquisition info is meant as feedback for the current operation.  Anything but
56  * FINGERPRINT_ACQUIRED_GOOD will be shown to the user as feedback on how to take action on the
57  * current operation. For example, FINGERPRINT_ACQUIRED_IMAGER_DIRTY can be used to tell the user
58  * to clean the sensor.  If this will cause the current operation to fail, an additional
59  * FINGERPRINT_ERROR_CANCELED can be sent to stop the operation in progress (e.g. enrollment).
60  * In general, these messages will result in a "Try again" message.
61  */
62 typedef enum fingerprint_acquired_info {
63     FINGERPRINT_ACQUIRED_GOOD = 0,
64     FINGERPRINT_ACQUIRED_PARTIAL = 1, /* sensor needs more data, i.e. longer swipe. */
65     FINGERPRINT_ACQUIRED_INSUFFICIENT = 2, /* image doesn't contain enough detail for recognition*/
66     FINGERPRINT_ACQUIRED_IMAGER_DIRTY = 3, /* sensor needs to be cleaned */
67     FINGERPRINT_ACQUIRED_TOO_SLOW = 4, /* mostly swipe-type sensors; not enough data collected */
68     FINGERPRINT_ACQUIRED_TOO_FAST = 5, /* for swipe and area sensors; tell user to slow down*/
69     FINGERPRINT_ACQUIRED_VENDOR_BASE = 1000 /* vendor-specific acquisition messages start here */
70 } fingerprint_acquired_info_t;
71 
72 typedef struct fingerprint_finger_id {
73     uint32_t gid;
74     uint32_t fid;
75 } fingerprint_finger_id_t;
76 
77 typedef struct fingerprint_enroll {
78     fingerprint_finger_id_t finger;
79     /* samples_remaining goes from N (no data collected, but N scans needed)
80      * to 0 (no more data is needed to build a template). */
81     uint32_t samples_remaining;
82     uint64_t msg; /* Vendor specific message. Used for user guidance */
83 } fingerprint_enroll_t;
84 
85 typedef struct fingerprint_removed {
86     fingerprint_finger_id_t finger;
87 } fingerprint_removed_t;
88 
89 typedef struct fingerprint_acquired {
90     fingerprint_acquired_info_t acquired_info; /* information about the image */
91 } fingerprint_acquired_t;
92 
93 typedef struct fingerprint_authenticated {
94     fingerprint_finger_id_t finger;
95     hw_auth_token_t hat;
96 } fingerprint_authenticated_t;
97 
98 typedef struct fingerprint_msg {
99     fingerprint_msg_type_t type;
100     union {
101         fingerprint_error_t error;
102         fingerprint_enroll_t enroll;
103         fingerprint_removed_t removed;
104         fingerprint_acquired_t acquired;
105         fingerprint_authenticated_t authenticated;
106     } data;
107 } fingerprint_msg_t;
108 
109 /* Callback function type */
110 typedef void (*fingerprint_notify_t)(const fingerprint_msg_t *msg);
111 
112 /* Synchronous operation */
113 typedef struct fingerprint_device {
114     /**
115      * Common methods of the fingerprint device. This *must* be the first member
116      * of fingerprint_device as users of this structure will cast a hw_device_t
117      * to fingerprint_device pointer in contexts where it's known
118      * the hw_device_t references a fingerprint_device.
119      */
120     struct hw_device_t common;
121 
122     /*
123      * Client provided callback function to receive notifications.
124      * Do not set by hand, use the function above instead.
125      */
126     fingerprint_notify_t notify;
127 
128     /*
129      * Set notification callback:
130      * Registers a user function that would receive notifications from the HAL
131      * The call will block if the HAL state machine is in busy state until HAL
132      * leaves the busy state.
133      *
134      * Function return: 0 if callback function is successfuly registered
135      *                  or a negative number in case of error, generally from the errno.h set.
136      */
137     int (*set_notify)(struct fingerprint_device *dev, fingerprint_notify_t notify);
138 
139     /*
140      * Fingerprint pre-enroll enroll request:
141      * Generates a unique token to upper layers to indicate the start of an enrollment transaction.
142      * This token will be wrapped by security for verification and passed to enroll() for
143      * verification before enrollment will be allowed. This is to ensure adding a new fingerprint
144      * template was preceded by some kind of credential confirmation (e.g. device password).
145      *
146      * Function return: 0 if function failed
147      *                  otherwise, a uint64_t of token
148      */
149     uint64_t (*pre_enroll)(struct fingerprint_device *dev);
150 
151     /*
152      * Fingerprint enroll request:
153      * Switches the HAL state machine to collect and store a new fingerprint
154      * template. Switches back as soon as enroll is complete
155      * (fingerprint_msg.type == FINGERPRINT_TEMPLATE_ENROLLING &&
156      *  fingerprint_msg.data.enroll.samples_remaining == 0)
157      * or after timeout_sec seconds.
158      * The fingerprint template will be assigned to the group gid. User has a choice
159      * to supply the gid or set it to 0 in which case a unique group id will be generated.
160      *
161      * Function return: 0 if enrollment process can be successfully started
162      *                  or a negative number in case of error, generally from the errno.h set.
163      *                  A notify() function may be called indicating the error condition.
164      */
165     int (*enroll)(struct fingerprint_device *dev, const hw_auth_token_t *hat,
166                     uint32_t gid, uint32_t timeout_sec);
167 
168     /*
169      * Finishes the enroll operation and invalidates the pre_enroll() generated challenge.
170      * This will be called at the end of a multi-finger enrollment session to indicate
171      * that no more fingers will be added.
172      *
173      * Function return: 0 if the request is accepted
174      *                  or a negative number in case of error, generally from the errno.h set.
175      */
176     int (*post_enroll)(struct fingerprint_device *dev);
177 
178     /*
179      * get_authenticator_id:
180      * Returns a token associated with the current fingerprint set. This value will
181      * change whenever a new fingerprint is enrolled, thus creating a new fingerprint
182      * set.
183      *
184      * Function return: current authenticator id or 0 if function failed.
185      */
186     uint64_t (*get_authenticator_id)(struct fingerprint_device *dev);
187 
188     /*
189      * Cancel pending enroll or authenticate, sending FINGERPRINT_ERROR_CANCELED
190      * to all running clients. Switches the HAL state machine back to the idle state.
191      * Unlike enroll_done() doesn't invalidate the pre_enroll() challenge.
192      *
193      * Function return: 0 if cancel request is accepted
194      *                  or a negative number in case of error, generally from the errno.h set.
195      */
196     int (*cancel)(struct fingerprint_device *dev);
197 
198     /*
199      * Enumerate all the fingerprint templates found in the directory set by
200      * set_active_group()
201      * This is a synchronous call. The function takes:
202      * - A pointer to an array of fingerprint_finger_id_t.
203      * - The size of the array provided, in fingerprint_finger_id_t elements.
204      * Max_size is a bi-directional parameter and returns the actual number
205      * of elements copied to the caller supplied array.
206      * In the absence of errors the function returns the total number of templates
207      * in the user directory.
208      * If the caller has no good guess on the size of the array he should call this
209      * function witn *max_size == 0 and use the return value for the array allocation.
210      * The caller of this function has a complete list of the templates when *max_size
211      * is the same as the function return.
212      *
213      * Function return: Total number of fingerprint templates in the current storage directory.
214      *                  or a negative number in case of error, generally from the errno.h set.
215      */
216     int (*enumerate)(struct fingerprint_device *dev, fingerprint_finger_id_t *results,
217         uint32_t *max_size);
218 
219     /*
220      * Fingerprint remove request:
221      * Deletes a fingerprint template.
222      * Works only within a path set by set_active_group().
223      * notify() will be called with details on the template deleted.
224      * fingerprint_msg.type == FINGERPRINT_TEMPLATE_REMOVED and
225      * fingerprint_msg.data.removed.id indicating the template id removed.
226      *
227      * Function return: 0 if fingerprint template(s) can be successfully deleted
228      *                  or a negative number in case of error, generally from the errno.h set.
229      */
230     int (*remove)(struct fingerprint_device *dev, uint32_t gid, uint32_t fid);
231 
232     /*
233      * Restricts the HAL operation to a set of fingerprints belonging to a
234      * group provided.
235      * The caller must provide a path to a storage location within the user's
236      * data directory.
237      *
238      * Function return: 0 on success
239      *                  or a negative number in case of error, generally from the errno.h set.
240      */
241     int (*set_active_group)(struct fingerprint_device *dev, uint32_t gid,
242                             const char *store_path);
243 
244     /*
245      * Authenticates an operation identifed by operation_id
246      *
247      * Function return: 0 on success
248      *                  or a negative number in case of error, generally from the errno.h set.
249      */
250     int (*authenticate)(struct fingerprint_device *dev, uint64_t operation_id, uint32_t gid);
251 
252     /* Reserved for backward binary compatibility */
253     void *reserved[4];
254 } fingerprint_device_t;
255 
256 typedef struct fingerprint_module {
257     /**
258      * Common methods of the fingerprint module. This *must* be the first member
259      * of fingerprint_module as users of this structure will cast a hw_module_t
260      * to fingerprint_module pointer in contexts where it's known
261      * the hw_module_t references a fingerprint_module.
262      */
263     struct hw_module_t common;
264 } fingerprint_module_t;
265 
266 #endif  /* ANDROID_INCLUDE_HARDWARE_FINGERPRINT_H */
267