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      1 /*
      2  * Copyright (C) 2006 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 __CUTILS_PROPERTIES_H
     18 #define __CUTILS_PROPERTIES_H
     19 
     20 #include <sys/cdefs.h>
     21 #include <stddef.h>
     22 #include <sys/system_properties.h>
     23 
     24 #ifdef __cplusplus
     25 extern "C" {
     26 #endif
     27 
     28 /* System properties are *small* name value pairs managed by the
     29 ** property service.  If your data doesn't fit in the provided
     30 ** space it is not appropriate for a system property.
     31 **
     32 ** WARNING: system/bionic/include/sys/system_properties.h also defines
     33 **          these, but with different names.  (TODO: fix that)
     34 */
     35 #define PROPERTY_KEY_MAX   PROP_NAME_MAX
     36 #define PROPERTY_VALUE_MAX  PROP_VALUE_MAX
     37 
     38 /* property_get: returns the length of the value which will never be
     39 ** greater than PROPERTY_VALUE_MAX - 1 and will always be zero terminated.
     40 ** (the length does not include the terminating zero).
     41 **
     42 ** If the property read fails or returns an empty value, the default
     43 ** value is used (if nonnull).
     44 */
     45 int property_get(const char *key, char *value, const char *default_value);
     46 
     47 /* property_set: returns 0 on success, < 0 on failure
     48 */
     49 int property_set(const char *key, const char *value);
     50 
     51 int property_list(void (*propfn)(const char *key, const char *value, void *cookie), void *cookie);
     52 
     53 #if defined(__BIONIC_FORTIFY)
     54 
     55 extern int __property_get_real(const char *, char *, const char *)
     56     __asm__(__USER_LABEL_PREFIX__ "property_get");
     57 __errordecl(__property_get_too_small_error, "property_get() called with too small of a buffer");
     58 
     59 __BIONIC_FORTIFY_INLINE
     60 int property_get(const char *key, char *value, const char *default_value) {
     61     size_t bos = __bos(value);
     62     if (bos < PROPERTY_VALUE_MAX) {
     63         __property_get_too_small_error();
     64     }
     65     return __property_get_real(key, value, default_value);
     66 }
     67 
     68 #endif
     69 
     70 #ifdef HAVE_SYSTEM_PROPERTY_SERVER
     71 /*
     72  * We have an external property server instead of built-in libc support.
     73  * Used by the simulator.
     74  */
     75 #define SYSTEM_PROPERTY_PIPE_NAME       "/tmp/android-sysprop"
     76 
     77 enum {
     78     kSystemPropertyUnknown = 0,
     79     kSystemPropertyGet,
     80     kSystemPropertySet,
     81     kSystemPropertyList
     82 };
     83 #endif /*HAVE_SYSTEM_PROPERTY_SERVER*/
     84 
     85 
     86 #ifdef __cplusplus
     87 }
     88 #endif
     89 
     90 #endif
     91