frameworks/native/services/fileinotify/FileInotify_M.cpp

/*******************************
程序功能：解析/debug_ramdisk/mount.cfg配置文件，把文件挂载到tmpfs内存中。避免频繁写入内部存储，提高EMMC使用寿命。

mount.cfg格式如下：
/data/user/0/com.ss.android.ugc.aweme.lite/databases/ss_app_log.db
/data/user/0/com.ss.android.ugc.aweme.lite/databases/ss_app_log.db-journal
********************************/

#define LOG_TAG "FileInotify"
#include <iostream>
#include <fstream>
#include <string>
#include <filesystem>
#include <utils/RefBase.h>
#include <utils/Log.h>
#include <cutils/properties.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <sys/inotify.h>
#include <pthread.h>
#include <sys/mount.h>
#include <sys/prctl.h>
#include <cstring>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/ioctl.h>

#define MOUNT_INFO_DEV    "/dev/minfo"
#define CMD_BASE          0xCBAABC10
#define FK_IS_GET_POWER2  (CMD_BASE + 12)
#define M_IOCTL_MAGIC     0xB3
#define MOUNT_INFO        _IOW(M_IOCTL_MAGIC, 0x41, unsigned long)
#define MOUNT_CFG         "/debug_ramdisk/mount.cfg"  //配置文件路径
#define MOUNT_MAX_LINE    64                 //最大的挂载数
#define READ_LINE         128                //文件路径缓存大小

struct fileinotify_info{
	int  containerid;                    //容器ID
	char src[MOUNT_MAX_LINE][READ_LINE]; //挂载原路径
	char dst[MOUNT_MAX_LINE][READ_LINE]; //挂载目标路径
	int  flag[MOUNT_MAX_LINE];           //挂载标记，0x00:未挂载，0xAA:已挂载
	int  line;                           //挂载文件数量
}__attribute__ ((packed));

#if 0
void createFile(const std::string& path)
{
	namespace fs = std::filesystem;
	//确保目录存在，如果不存在则创建
	fs::create_directories(fs::path(path).parent_path());

	//创建文件
	std::ofstream file(path);
	if (file.is_open()) {
		file.close();
	}
}
#else
bool createDirectory(const std::string &path)
{
	size_t pos = 0;
	std::string currentPath;
	while ((pos = path.find('/', pos)) != std::string::npos) 
	{
		currentPath = path.substr(0, pos++);
		if (currentPath.empty()) continue;

		// 检查当前目录是否存在
		if (mkdir(currentPath.c_str(), 0777) != 0) {
			if (errno != EEXIST) {  // 如果目录不存在且无法创建
				return false;
			}
		}
	}

	// 创建完整路径
	if (mkdir(path.c_str(), 0777) != 0 && errno != EEXIST)
	{
		return false;
	}

	return true;
}

bool createFile(const std::string &filePath) {
	// 提取目录路径
	size_t lastSlash = filePath.find_last_of('/');
	if (lastSlash != std::string::npos) 
	{
		std::string directory = filePath.substr(0, lastSlash);
	
		// 创建目录
		if (!createDirectory(directory)) {
			return false;
		}
	}

	// 创建文件
	std::ofstream ofs(filePath);
	if (!ofs) {
		return false;
	}

	ofs.close();
	return true;
}
#endif

int mount_info_init(struct fileinotify_info *info)
{
	const std::string str = "/data_mirror";
	int i = 0;

	std::ifstream file(MOUNT_CFG);
	if (!file.is_open()) {
		return 0;
	}

	std::string line;
	while (std::getline(file, line)) {
		//std::cout << line << std::endl;
		if(line.size() > 0)
		{
			//create file
    			createFile(str + line);
			//save mount info
			sprintf(info->dst[i], "%s", line.c_str());
			sprintf(info->src[i], "/data_mirror%s", line.c_str());
			info->line = i + 1;
			i++;
		}
	}

	file.close();
	return info->line;
}

int file_exists(const char *filename)
{
	return access(filename, F_OK) == 0;
}

int main(void)
{
	struct fileinotify_info info;
	char buf[READ_LINE];
	int fd, ret;
	int line;

	//selinux
	prctl(FK_IS_GET_POWER2, 0, 0, 0);

	//file_exists
	if(!file_exists(MOUNT_CFG))
	goto OUT;

	//mount info init
	umask(0000);
	mount_info_init(&info);
	//for(int i = 0; i < info.line; i++)
	//{
	//	ALOGD("line=%d, src=%s, dst=%s\n", i, info.src[i], info.dst[i]);
	//}

	fd = open(MOUNT_INFO_DEV, O_RDWR | O_NONBLOCK | O_NOCTTY);
	if(fd < 0)
	{
		ALOGD("open minfo fail.\n");
		return -1;
	}

	ret = ioctl(fd, MOUNT_INFO, &info);
	if(ret != 0)
	{
		close(fd);
		ALOGD("ioctl minfo fail.\n");
		return -2;
	}

	close(fd);

OUT:
	return 0;
}