Magisk/native/jni/resetprop/persist_properties.cpp

#include <pb.h>
#include <pb_decode.h>
#include <pb_encode.h>

#include <utils.hpp>

#include "_resetprop.hpp"

using namespace std;

/* ***********************************************************************
 * Auto generated header and field definitions compiled from
 * https://android.googlesource.com/platform/system/core/+/master/init/persistent_properties.proto
 * Generated with Nanopb: https://github.com/nanopb/nanopb
 * ***********************************************************************/

/* Automatically generated nanopb header */
/* Generated by nanopb-0.4.3 */

#if PB_PROTO_HEADER_VERSION != 40
#error Regenerate this file with the current version of nanopb generator.
#endif

/* Struct definitions */
struct PersistentProperties {
	pb_callback_t properties;
};

struct PersistentProperties_PersistentPropertyRecord {
	pb_callback_t name;
	bool has_value;
	char value[92];
};

/* Initializer values for message structs */
#define PersistentProperties_init_default        {{{NULL}, NULL}}
#define PersistentProperties_PersistentPropertyRecord_init_default {{{NULL}, NULL}, false, ""}
#define PersistentProperties_init_zero           {{{NULL}, NULL}}
#define PersistentProperties_PersistentPropertyRecord_init_zero {{{NULL}, NULL}, false, ""}

/* Field tags (for use in manual encoding/decoding) */
#define PersistentProperties_properties_tag      1
#define PersistentProperties_PersistentPropertyRecord_name_tag 1
#define PersistentProperties_PersistentPropertyRecord_value_tag 2

/* Struct field encoding specification for nanopb */
#define PersistentProperties_FIELDLIST(X, a) \
X(a, CALLBACK, REPEATED, MESSAGE,  properties,        1)
#define PersistentProperties_CALLBACK pb_default_field_callback
#define PersistentProperties_DEFAULT NULL
#define PersistentProperties_properties_MSGTYPE PersistentProperties_PersistentPropertyRecord

#define PersistentProperties_PersistentPropertyRecord_FIELDLIST(X, a) \
X(a, CALLBACK, OPTIONAL, STRING,   name,              1) \
X(a, STATIC,   OPTIONAL, STRING,   value,             2)
#define PersistentProperties_PersistentPropertyRecord_CALLBACK pb_default_field_callback
#define PersistentProperties_PersistentPropertyRecord_DEFAULT NULL

extern const pb_msgdesc_t PersistentProperties_msg;
extern const pb_msgdesc_t PersistentProperties_PersistentPropertyRecord_msg;

/* Defines for backwards compatibility with code written before nanopb-0.4.0 */
#define PersistentProperties_fields &PersistentProperties_msg
#define PersistentProperties_PersistentPropertyRecord_fields &PersistentProperties_PersistentPropertyRecord_msg

/* Maximum encoded size of messages (where known) */
/* PersistentProperties_size depends on runtime parameters */
/* PersistentProperties_PersistentPropertyRecord_size depends on runtime parameters */

PB_BIND(PersistentProperties, PersistentProperties, AUTO)

PB_BIND(PersistentProperties_PersistentPropertyRecord, PersistentProperties_PersistentPropertyRecord, AUTO)

/* ***************************
 * End of auto generated code
 * ***************************/

bool use_pb = false;

static bool name_decode(pb_istream_t *stream, const pb_field_t *field, void **arg) {
	string &name = *static_cast<string *>(*arg);
	name.resize(stream->bytes_left);
	return pb_read(stream, (pb_byte_t *)(name.data()), stream->bytes_left);
}

static bool name_encode(pb_ostream_t *stream, const pb_field_t *field, void * const *arg) {
	return pb_encode_tag_for_field(stream, field) &&
		   pb_encode_string(stream, (const pb_byte_t *) *arg, strlen((const char *) *arg));
}

static bool prop_decode(pb_istream_t *stream, const pb_field_t *field, void **arg) {
	PersistentProperties_PersistentPropertyRecord prop{};
	string name;
	prop.name.funcs.decode = name_decode;
	prop.name.arg = &name;
	if (!pb_decode(stream, &PersistentProperties_PersistentPropertyRecord_msg, &prop))
		return false;
	auto cb = static_cast<prop_cb*>(*arg);
	cb->exec(std::move(name), prop.value);
	return true;
}

static bool prop_encode(pb_ostream_t *stream, const pb_field_t *field, void * const *arg) {
	PersistentProperties_PersistentPropertyRecord prop{};
	prop.name.funcs.encode = name_encode;
	prop.has_value = true;
	auto &list = *static_cast<prop_list *>(*arg);
	for (auto &p : list) {
		if (!pb_encode_tag_for_field(stream, field))
			return false;
		prop.name.arg = (void *) p.first.data();
		strcpy(prop.value, p.second.data());
		if (!pb_encode_submessage(stream, &PersistentProperties_PersistentPropertyRecord_msg, &prop))
			return false;
	}
	return true;
}

static bool write_callback(pb_ostream_t *stream, const uint8_t *buf, size_t count) {
	int fd = (intptr_t)stream->state;
	return xwrite(fd, buf, count) == count;
}

static pb_ostream_t create_ostream(const char *filename) {
	int fd = creat(filename, 0644);
	pb_ostream_t o = {
		.callback = write_callback,
		.state = (void*)(intptr_t)fd,
		.max_size = SIZE_MAX,
		.bytes_written = 0,
	};
	return o;
}

static void pb_getprop(prop_cb *prop_cb) {
	LOGD("resetprop: decode with protobuf [" PERSISTENT_PROPERTY_DIR "/persistent_properties]\n");
	PersistentProperties props = {};
	props.properties.funcs.decode = prop_decode;
	props.properties.arg = prop_cb;
	pb_byte_t *buf;
	size_t size;
	mmap_ro(PERSISTENT_PROPERTY_DIR "/persistent_properties", buf, size);
	pb_istream_t stream = pb_istream_from_buffer(buf, size);
	pb_decode(&stream, &PersistentProperties_msg, &props);
	munmap(buf, size);
}

static bool file_getprop(const char *name, char *value) {
	char path[4096];
	snprintf(path, sizeof(path), PERSISTENT_PROPERTY_DIR "/%s", name);
	int fd = open(path, O_RDONLY | O_CLOEXEC);
	if (fd < 0)
		return false;
	LOGD("resetprop: read prop from [%s]\n", path);
	value[read(fd, value, PROP_VALUE_MAX - 1)] = '\0';  // Null terminate the read value
	close(fd);
	return value[0] != '\0';
}

void persist_getprops(prop_cb *prop_cb) {
	if (use_pb) {
		pb_getprop(prop_cb);
	} else {
		auto dir = open_dir(PERSISTENT_PROPERTY_DIR);
		if (!dir) return;
		for (dirent *entry; (entry = xreaddir(dir.get()));) {
			char value[PROP_VALUE_MAX];
			if (file_getprop(entry->d_name, value))
				prop_cb->exec(entry->d_name, value);
		}
	}
}

struct match_prop_name : prop_cb {
	explicit match_prop_name(const char *name) : _name(name) { value[0] = '\0'; }
	void exec(string &&name, const char *val) override {
		if (name == _name)
			strcpy(value, val);
	}
	char value[PROP_VALUE_MAX];
private:
	const char *_name;
};

string persist_getprop(const char *name) {
	if (use_pb) {
		auto prop = match_prop_name(name);
		pb_getprop(&prop);
		if (prop.value[0]) {
			LOGD("resetprop: getprop (persist) [%s]: [%s]\n", name, prop.value);
			return prop.value;
		}
	} else {
		// Try to read from file
		char value[PROP_VALUE_MAX];
		if (file_getprop(name, value)) {
			LOGD("resetprop: getprop (persist) [%s]: [%s]\n", name, value);
			return value;
		}
	}
	return string();
}

bool persist_deleteprop(const char *name) {
	if (use_pb) {
		prop_list list;
		prop_collector collector(list);
		persist_getprops(&collector);

		for (auto it = list.begin(); it != list.end(); ++it) {
			if (it->first == name) {
				list.erase(it);
				// Dump the props back
				PersistentProperties props{};
				pb_ostream_t ostream = create_ostream(PERSISTENT_PROPERTY_DIR
						"/persistent_properties.tmp");
				props.properties.funcs.encode = prop_encode;
				props.properties.arg = &list;
				LOGD("resetprop: encode with protobuf [" PERSISTENT_PROPERTY_DIR
							 "/persistent_properties.tmp]\n");
				if (!pb_encode(&ostream, &PersistentProperties_msg, &props))
					return false;
				clone_attr(PERSISTENT_PROPERTY_DIR "/persistent_properties",
						   PERSISTENT_PROPERTY_DIR "/persistent_properties.tmp");
				rename(PERSISTENT_PROPERTY_DIR "/persistent_properties.tmp",
					   PERSISTENT_PROPERTY_DIR "/persistent_properties");
				return true;
			}
		}
		return false;
	} else {
		char path[4096];
		snprintf(path, sizeof(path), PERSISTENT_PROPERTY_DIR "/%s", name);
		if (unlink(path) == 0) {
			LOGD("resetprop: unlink [%s]\n", path);
			return true;
		}
	}
	return false;
}