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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 #include <cutils/properties.h>
     18 
     19 #define LOG_TAG "properties"
     20 // #define LOG_NDEBUG 0
     21 
     22 #include <assert.h>
     23 #include <ctype.h>
     24 #include <errno.h>
     25 #include <inttypes.h>
     26 #include <stdlib.h>
     27 #include <string.h>
     28 #include <unistd.h>
     29 
     30 #include <cutils/sockets.h>
     31 #include <log/log.h>
     32 
     33 int8_t property_get_bool(const char *key, int8_t default_value) {
     34     if (!key) {
     35         return default_value;
     36     }
     37 
     38     int8_t result = default_value;
     39     char buf[PROPERTY_VALUE_MAX] = {'\0'};
     40 
     41     int len = property_get(key, buf, "");
     42     if (len == 1) {
     43         char ch = buf[0];
     44         if (ch == '0' || ch == 'n') {
     45             result = false;
     46         } else if (ch == '1' || ch == 'y') {
     47             result = true;
     48         }
     49     } else if (len > 1) {
     50         if (!strcmp(buf, "no") || !strcmp(buf, "false") || !strcmp(buf, "off")) {
     51             result = false;
     52         } else if (!strcmp(buf, "yes") || !strcmp(buf, "true") || !strcmp(buf, "on")) {
     53             result = true;
     54         }
     55     }
     56 
     57     return result;
     58 }
     59 
     60 // Convert string property to int (default if fails); return default value if out of bounds
     61 static intmax_t property_get_imax(const char *key, intmax_t lower_bound, intmax_t upper_bound,
     62                                   intmax_t default_value) {
     63     if (!key) {
     64         return default_value;
     65     }
     66 
     67     intmax_t result = default_value;
     68     char buf[PROPERTY_VALUE_MAX] = {'\0'};
     69     char *end = NULL;
     70 
     71     int len = property_get(key, buf, "");
     72     if (len > 0) {
     73         int tmp = errno;
     74         errno = 0;
     75 
     76         // Infer base automatically
     77         result = strtoimax(buf, &end, /*base*/ 0);
     78         if ((result == INTMAX_MIN || result == INTMAX_MAX) && errno == ERANGE) {
     79             // Over or underflow
     80             result = default_value;
     81             ALOGV("%s(%s,%" PRIdMAX ") - overflow", __FUNCTION__, key, default_value);
     82         } else if (result < lower_bound || result > upper_bound) {
     83             // Out of range of requested bounds
     84             result = default_value;
     85             ALOGV("%s(%s,%" PRIdMAX ") - out of range", __FUNCTION__, key, default_value);
     86         } else if (end == buf) {
     87             // Numeric conversion failed
     88             result = default_value;
     89             ALOGV("%s(%s,%" PRIdMAX ") - numeric conversion failed", __FUNCTION__, key,
     90                   default_value);
     91         }
     92 
     93         errno = tmp;
     94     }
     95 
     96     return result;
     97 }
     98 
     99 int64_t property_get_int64(const char *key, int64_t default_value) {
    100     return (int64_t)property_get_imax(key, INT64_MIN, INT64_MAX, default_value);
    101 }
    102 
    103 int32_t property_get_int32(const char *key, int32_t default_value) {
    104     return (int32_t)property_get_imax(key, INT32_MIN, INT32_MAX, default_value);
    105 }
    106 
    107 #define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
    108 #include <sys/_system_properties.h>
    109 
    110 int property_set(const char *key, const char *value) {
    111     return __system_property_set(key, value);
    112 }
    113 
    114 int property_get(const char *key, char *value, const char *default_value) {
    115     int len = __system_property_get(key, value);
    116     if (len > 0) {
    117         return len;
    118     }
    119     if (default_value) {
    120         len = strnlen(default_value, PROPERTY_VALUE_MAX - 1);
    121         memcpy(value, default_value, len);
    122         value[len] = '\0';
    123     }
    124     return len;
    125 }
    126 
    127 struct callback_data {
    128     void (*callback)(const char* name, const char* value, void* cookie);
    129     void* cookie;
    130 };
    131 
    132 static void trampoline(void* raw_data, const char* name, const char* value, unsigned /*serial*/) {
    133     callback_data* data = reinterpret_cast<callback_data*>(raw_data);
    134     data->callback(name, value, data->cookie);
    135 }
    136 
    137 static void property_list_callback(const prop_info* pi, void* data) {
    138     __system_property_read_callback(pi, trampoline, data);
    139 }
    140 
    141 int property_list(void (*fn)(const char* name, const char* value, void* cookie), void* cookie) {
    142     callback_data data = { fn, cookie };
    143     return __system_property_foreach(property_list_callback, &data);
    144 }
    145