Update resetprop to partially use system impl

native/jni/include/resetprop.hpp

@@ -3,7 +3,6 @@
 #include <string>
 #include <functional>
 
-bool prop_exist(const char *name);
 int setprop(const char *name, const char *value, bool trigger = true);
 std::string getprop(const char *name, bool persist = false);
 void getprops(void (*callback)(const char *, const char *, void *),

native/jni/resetprop/persist_properties.cpp

@@ -88,6 +88,8 @@ const pb_field_t PersistentProperties_fields[2] = {
  * End of auto generated code
  * ***************************/
 
+bool use_pb = false;
+
 #ifdef APPLET_STUB_MAIN
 struct {
 	void push_back(...){};

native/jni/resetprop/resetprop.cpp

@@ -1,10 +1,4 @@
-#include <stdio.h>
+#include <dlfcn.h>
-#include <stdint.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <fcntl.h>
-#include <string.h>
-#include <dirent.h>
 #include <sys/types.h>
 #include <vector>
 #include <map>
@@ -21,37 +15,10 @@
 
 using namespace std;
 
-bool use_pb = false;
 static bool verbose = false;
 
-static bool check_legal_property_name(const char *name) {
+static int (*system_property_get)(const char*, char*);
-	int namelen = strlen(name);
+static int (*system_property_set)(const char*, const char*);
-
-	if (namelen < 1) goto illegal;
-	if (name[0] == '.') goto illegal;
-	if (name[namelen - 1] == '.') goto illegal;
-
-	/* Only allow alphanumeric, plus '.', '-', '@', ':', or '_' */
-	/* Don't allow ".." to appear in a property name */
-	for (size_t i = 0; i < namelen; i++) {
-		if (name[i] == '.') {
-			// i=0 is guaranteed to never have a dot. See above.
-			if (name[i-1] == '.') goto illegal;
-			continue;
-		}
-		if (name[i] == '_' || name[i] == '-' || name[i] == '@' || name[i] == ':') continue;
-		if (name[i] >= 'a' && name[i] <= 'z') continue;
-		if (name[i] >= 'A' && name[i] <= 'Z') continue;
-		if (name[i] >= '0' && name[i] <= '9') continue;
-		goto illegal;
-	}
-
-	return true;
-
-illegal:
-	LOGE("Illegal property name: [%s]\n", name);
-	return false;
-}
 
 [[noreturn]] static void usage(char* arg0) {
 	fprintf(stderr,
@@ -78,126 +45,200 @@ Flags:
 	exit(1);
 }
 
-static void read_props(const prop_info *pi, void *cb) {
+static bool check_legal_property_name(const char *name) {
+	int namelen = strlen(name);
+
+	if (namelen < 1) goto illegal;
+	if (name[0] == '.') goto illegal;
+	if (name[namelen - 1] == '.') goto illegal;
+
+	/* Only allow alphanumeric, plus '.', '-', '@', ':', or '_' */
+	/* Don't allow ".." to appear in a property name */
+	for (size_t i = 0; i < namelen; i++) {
+		if (name[i] == '.') {
+			// i=0 is guaranteed to never have a dot. See above.
+			if (name[i-1] == '.') goto illegal;
+			continue;
+		}
+		if (name[i] == '_' || name[i] == '-' || name[i] == '@' || name[i] == ':') continue;
+		if (name[i] >= 'a' && name[i] <= 'z') continue;
+		if (name[i] >= 'A' && name[i] <= 'Z') continue;
+		if (name[i] >= '0' && name[i] <= '9') continue;
+		goto illegal;
+	}
+
+	return true;
+
+	illegal:
+	LOGE("Illegal property name: [%s]\n", name);
+	return false;
+}
+
+static void read_prop(const prop_info *pi, void *cb) {
 	__system_property_read_callback(
 			pi, [](auto cb, auto name, auto value, auto) {
 				reinterpret_cast<prop_cb*>(cb)->exec(name, value);
 			}, cb);
 }
 
-static int init_resetprop() {
-	use_pb = use_pb ? true : access(PERSISTENT_PROPERTY_DIR "/persistent_properties", R_OK) == 0;
-	if (__system_properties_init()) {
-		LOGE("resetprop: Initialize error\n");
-		return -1;
-	}
-	return 0;
-}
-
 static void print_props(bool persist) {
 	getprops([](auto name, auto value, auto) {
 		printf("[%s]: [%s]\n", name, value);
 	}, nullptr, persist);
 }
 
-/* **************************************************
+struct sysprop {
- * Implementations of functions in resetprop.h (APIs)
+	virtual int setprop(const char *name, const char *value, bool trigger) { return 1; }
- * **************************************************/
+	virtual string getprop(const char *name, bool persist) { return ""; }
+	virtual void getprops(void (*callback)(const char *, const char *, void *),
+			void *cookie, bool persist) {}
+	virtual int delprop(const char *name, bool persist) { return 1; }
+};
 
-#define ENSURE_INIT(ret) if (init_resetprop()) return ret
+struct stock_sysprop : public sysprop {
-
+	int setprop(const char *name, const char *value, bool) override {
-bool prop_exist(const char *name) {
+		return system_property_set(name, value);
-	ENSURE_INIT(false);
+	}
-	return __system_property_find(name) != nullptr;
+	string getprop(const char *name, bool) override {
-}
-
-// Get prop by name, return string
-string getprop(const char *name, bool persist) {
-	if (!check_legal_property_name(name))
-		return string();
-	ENSURE_INIT(string());
-	const prop_info *pi = __system_property_find(name);
-	if (pi == nullptr) {
-		if (persist && strncmp(name, "persist.", 8) == 0) {
-			auto value = persist_getprop(name);
-			if (value.empty())
-				goto not_found;
-			return value;
-		}
-not_found:
-		LOGD("resetprop: prop [%s] does not exist\n", name);
-		return string();
-	} else {
 		char buf[PROP_VALUE_MAX];
-		auto reader = make_prop_cb(buf, [](auto, auto value, auto buf) { strcpy(buf, value); });
+		buf[0] = '\0';
-		read_props(pi, &reader);
+		system_property_get(name, buf);
-		LOGD("resetprop: getprop [%s]: [%s]\n", name, buf);
 		return buf;
 	}
+};
+
+struct resetprop : public sysprop {
+	int setprop(const char *name, const char *value, bool trigger) override {
+		if (!check_legal_property_name(name))
+			return 1;
+
+		int ret;
+		auto pi = const_cast<prop_info *>(__system_property_find(name));
+		if (pi != nullptr) {
+			if (trigger) {
+				if (strncmp(name, "ro.", 3) == 0)
+					delprop(name, false);
+				ret = system_property_set(name, value);
+			} else {
+				ret = __system_property_update(pi, value, strlen(value));
+			}
+			LOGD("resetprop: update prop [%s]: [%s] by %s\n", name, value,
+				 trigger ? "property_service" : "modifying prop data structure");
+		} else {
+			if (trigger) {
+				ret = system_property_set(name, value);
+			} else {
+				ret = __system_property_add(name, strlen(name), value, strlen(value));
+			}
+			LOGD("resetprop: create prop [%s]: [%s] by %s\n", name, value,
+				 trigger ? "property_service" : "modifying prop data structure");
+		}
+
+		if (ret)
+			LOGE("resetprop: setprop error\n");
+
+		return ret;
+	}
+
+	string getprop(const char *name, bool persist) override {
+		if (!check_legal_property_name(name))
+			return string();
+		auto pi = __system_property_find(name);
+		if (pi == nullptr) {
+			if (persist && strncmp(name, "persist.", 8) == 0) {
+				auto value = persist_getprop(name);
+				if (value.empty())
+					goto not_found;
+				return value;
+			}
+			not_found:
+			LOGD("resetprop: prop [%s] does not exist\n", name);
+			return string();
+		} else {
+			string val;
+			auto reader = make_prop_cb(val, [](auto, auto value, auto str){ str = value; });
+			read_prop(pi, &reader);
+			LOGD("resetprop: getprop [%s]: [%s]\n", name, val.data());
+			return val;
+		}
+	}
+
+	void getprops(void (*callback)(const char *, const char *, void *),
+			void *cookie, bool persist) override {
+		prop_list list;
+		prop_collector collector(list);
+		__system_property_foreach(read_prop, &collector);
+		if (persist)
+			persist_getprops(&collector);
+		for (auto &[key, val] : list)
+			callback(key.data(), val.data(), cookie);
+		if (persist)
+			persist_cleanup();
+	}
+
+	int delprop(const char *name, bool persist) override {
+		if (!check_legal_property_name(name))
+			return 1;
+		LOGD("resetprop: delete prop [%s]\n", name);
+		if (persist && strncmp(name, "persist.", 8) == 0)
+			persist = persist_deleteprop(name);
+		return __system_property_delete(name) && !(persist && strncmp(name, "persist.", 8) == 0);
+	}
+};
+
+#define DLOAD(name) \
+*(void **) &name = dlsym(RTLD_DEFAULT, "__" #name)
+
+static sysprop *get_impl() {
+	static sysprop *impl = nullptr;
+	if (impl == nullptr) {
+		use_pb = access(PERSISTENT_PROPERTY_DIR "/persistent_properties", R_OK) == 0;
+#ifdef APPLET_STUB_MAIN
+		if (__system_properties_init()) {
+			LOGE("resetprop: __system_properties_init error\n");
+			exit(1);
+		}
+		impl = new resetprop();
+		system_property_set = &__system_property_set;
+#else
+		DLOAD(system_property_set);  /* Always prefer to use setprop from platform */
+		if (__system_properties_init()) {
+			LOGW("resetprop: __system_properties_init error\n");
+			DLOAD(system_property_get);
+			impl = system_property_get ? new stock_sysprop() : new sysprop();
+		} else {
+			impl = new resetprop();
+		}
+#endif
+	}
+	return impl;
+}
+
+/*********************************
+ * Implementation of public APIs
+ *********************************/
+
+string getprop(const char *name, bool persist) {
+	return get_impl()->getprop(name, persist);
 }
 
 void getprops(void (*callback)(const char *, const char *, void *), void *cookie, bool persist) {
-	ENSURE_INIT();
+	get_impl()->getprops(callback, cookie, persist);
-	prop_list list;
-	prop_collector collector(list);
-	__system_property_foreach(read_props, &collector);
-	if (persist)
-		persist_getprops(&collector);
-	for (auto &[key, val] : list)
-		callback(key.data(), val.data(), cookie);
-	persist_cleanup();
 }
 
 int setprop(const char *name, const char *value, bool trigger) {
-	if (!check_legal_property_name(name))
+	return get_impl()->setprop(name, value, trigger);
-		return 1;
-	ENSURE_INIT(-1);
-
-	int ret;
-
-	auto pi = (prop_info*) __system_property_find(name);
-	if (pi != nullptr) {
-		if (trigger) {
-			if (strncmp(name, "ro.", 3) == 0) delprop(name);
-			ret = __system_property_set(name, value);
-		} else {
-			ret = __system_property_update(pi, value, strlen(value));
-		}
-	} else {
-		LOGD("resetprop: New prop [%s]\n", name);
-		if (trigger) {
-			ret = __system_property_set(name, value);
-		} else {
-			ret = __system_property_add(name, strlen(name), value, strlen(value));
-		}
-	}
-
-	LOGD("resetprop: setprop [%s]: [%s] by %s\n", name, value,
-		trigger ? "property_service" : "modifing prop data structure");
-
-	if (ret)
-		LOGE("resetprop: setprop error\n");
-
-	return ret;
 }
 
 int delprop(const char *name, bool persist) {
-	if (!check_legal_property_name(name))
+	return get_impl()->delprop(name, persist);
-		return 1;
-	ENSURE_INIT(-1);
-	char path[PATH_MAX];
-	path[0] = '\0';
-	LOGD("resetprop: delprop [%s]\n", name);
-	if (persist && strncmp(name, "persist.", 8) == 0)
-		persist = persist_deleteprop(name);
-	return __system_property_del(name) && !(persist && strncmp(name, "persist.", 8) == 0);
 }
 
 void load_prop_file(const char *filename, bool trigger) {
-	ENSURE_INIT();
+	auto impl = get_impl();
 	LOGD("resetprop: Parse prop file [%s]\n", filename);
 	parse_prop_file(filename, [=](auto key, auto val) -> bool {
-		setprop(key.data(), val.data(), trigger);
+		impl->setprop(key.data(), val.data(), trigger);
 		return true;
 	});
 }
@@ -253,7 +294,7 @@ int resetprop_main(int argc, char *argv[]) {
 	case 1:
 		prop = getprop(argv[0], persist);
 		if (prop.empty()) return 1;
-		printf("%s\n", prop.c_str());
+		printf("%s\n", prop.data());
 		return 0;
 	case 2:
 		return setprop(argv[0], argv[1], trigger);

native/jni/systemproperties/include/_system_properties.h

@@ -109,7 +109,7 @@ int __system_property_add(const char* __name, unsigned int __name_length, const
 **
 ** Returns 0 on success, -1 if the property area is full.
 */
-int __system_property_del(const char *__name);
+int __system_property_delete(const char *__name);
 
 /* Update the value of a system property returned by
 ** __system_property_find.  Can only be done by a single process

native/jni/systemproperties/system_property_api.cpp

@@ -100,7 +100,7 @@ int __system_property_add(const char* name, unsigned int namelen, const char* va
 }
 
 __BIONIC_WEAK_FOR_NATIVE_BRIDGE
-int __system_property_del(const char* name) {
+int __system_property_delete(const char* name) {
   return system_properties.Delete(name);
 }