cutils: Add property_get_bool, _get_int32, _get_int64

* Read out system properties with same syntax as SystemProperties.java
* Also adds unit test suite to validate correctness of properties
* Also fixes buffer overrun in property_get

(cherry picked from commit d4507e9246e4855c5431cac5c3d1a9155caebc87)

Change-Id: Ifd42911f93e17da09e6ff1298e8875e02f3b6608

1 files changed, 82 insertions, 2 deletions

diff --git a/libcutils/properties.c b/libcutils/properties.c
index 28d8b2f..bfbd1b8 100644
--- a/libcutils/properties.c
+++ b/libcutils/properties.c
@@ -15,17 +15,94 @@
  */
 
 #define LOG_TAG "properties"
+// #define LOG_NDEBUG 0
 
 #include <stdlib.h>
 #include <string.h>
+#include <ctype.h>
 #include <unistd.h>
 #include <cutils/sockets.h>
 #include <errno.h>
 #include <assert.h>
 
 #include <cutils/properties.h>
+#include <stdbool.h>
+#include <inttypes.h>
 #include "loghack.h"
 
+int8_t property_get_bool(const char *key, int8_t default_value) {
+    if (!key) {
+        return default_value;
+    }
+
+    int8_t result = default_value;
+    char buf[PROPERTY_VALUE_MAX] = {'\0',};
+
+    int len = property_get(key, buf, "");
+    if (len == 1) {
+        char ch = buf[0];
+        if (ch == '0' || ch == 'n') {
+            result = false;
+        } else if (ch == '1' || ch == 'y') {
+            result = true;
+        }
+    } else if (len > 1) {
+         if (!strcmp(buf, "no") || !strcmp(buf, "false") || !strcmp(buf, "off")) {
+            result = false;
+        } else if (!strcmp(buf, "yes") || !strcmp(buf, "true") || !strcmp(buf, "on")) {
+            result = true;
+        }
+    }
+
+    return result;
+}
+
+// Convert string property to int (default if fails); return default value if out of bounds
+static intmax_t property_get_imax(const char *key, intmax_t lower_bound, intmax_t upper_bound,
+        intmax_t default_value) {
+    if (!key) {
+        return default_value;
+    }
+
+    intmax_t result = default_value;
+    char buf[PROPERTY_VALUE_MAX] = {'\0',};
+    char *end = NULL;
+
+    int len = property_get(key, buf, "");
+    if (len > 0) {
+        int tmp = errno;
+        errno = 0;
+
+        // Infer base automatically
+        result = strtoimax(buf, &end, /*base*/0);
+        if ((result == INTMAX_MIN || result == INTMAX_MAX) && errno == ERANGE) {
+            // Over or underflow
+            result = default_value;
+            ALOGV("%s(%s,%lld) - overflow", __FUNCTION__, key, default_value);
+        } else if (result < lower_bound || result > upper_bound) {
+            // Out of range of requested bounds
+            result = default_value;
+            ALOGV("%s(%s,%lld) - out of range", __FUNCTION__, key, default_value);
+        } else if (end == buf) {
+            // Numeric conversion failed
+            result = default_value;
+            ALOGV("%s(%s,%lld) - numeric conversion failed", __FUNCTION__, key, default_value);
+        }
+
+        errno = tmp;
+    }
+
+    return result;
+}
+
+int64_t property_get_int64(const char *key, int64_t default_value) {
+    return (int64_t)property_get_imax(key, INT64_MIN, INT64_MAX, default_value);
+}
+
+int32_t property_get_int32(const char *key, int32_t default_value) {
+    return (int32_t)property_get_imax(key, INT32_MIN, INT32_MAX, default_value);
+}
+
 #ifdef HAVE_LIBC_SYSTEM_PROPERTIES
 
 #define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
@@ -44,10 +121,13 @@ int property_get(const char *key, char *value, const char *default_value)
     if(len > 0) {
         return len;
     }
-    
     if(default_value) {
         len = strlen(default_value);
-        memcpy(value, default_value, len + 1);
+        if (len >= PROPERTY_VALUE_MAX) {
+            len = PROPERTY_VALUE_MAX - 1;
+        }
+        memcpy(value, default_value, len);
+        value[len] = '\0';
     }
     return len;
 }