Support arbitrary-length properties in property_list.

Bug: http://b/33926793
Test: visual inspection
Change-Id: Ida84c3aaafa5411a9886f8d3d45679fd60ddc00d
diff --git a/libcutils/properties.cpp b/libcutils/properties.cpp
new file mode 100644
index 0000000..43ad574
--- /dev/null
+++ b/libcutils/properties.cpp
@@ -0,0 +1,144 @@
+/*
+ * Copyright (C) 2006 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "properties"
+// #define LOG_NDEBUG 0
+
+#include <assert.h>
+#include <ctype.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <cutils/properties.h>
+#include <cutils/sockets.h>
+#include <log/log.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,%" PRIdMAX ") - 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,%" PRIdMAX ") - out of range", __FUNCTION__, key, default_value);
+        } else if (end == buf) {
+            // Numeric conversion failed
+            result = default_value;
+            ALOGV("%s(%s,%" PRIdMAX ") - 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);
+}
+
+#define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
+#include <sys/_system_properties.h>
+
+int property_set(const char *key, const char *value) {
+    return __system_property_set(key, value);
+}
+
+int property_get(const char *key, char *value, const char *default_value) {
+    int len = __system_property_get(key, value);
+    if (len > 0) {
+        return len;
+    }
+    if (default_value) {
+        len = strnlen(default_value, PROPERTY_VALUE_MAX - 1);
+        memcpy(value, default_value, len);
+        value[len] = '\0';
+    }
+    return len;
+}
+
+struct callback_data {
+    void (*callback)(const char* name, const char* value, void* cookie);
+    void* cookie;
+};
+
+static void trampoline(void* raw_data, const char* name, const char* value) {
+    callback_data* data = reinterpret_cast<callback_data*>(raw_data);
+    data->callback(name, value, data->cookie);
+}
+
+static void property_list_callback(const prop_info* pi, void* data) {
+    __system_property_read_callback(pi, trampoline, data);
+}
+
+int property_list(void (*fn)(const char* name, const char* value, void* cookie), void* cookie) {
+    callback_data data = { fn, cookie };
+    return __system_property_foreach(property_list_callback, &data);
+}