statfs

/****************************************************************************
@File Name: statfs.h
@Author: wangzhicheng
@mail: 2363702560@qq.com
@Created Time: Tue 28 Feb 2017 05:15:08 PM CST
			   2017-03-01
****************************************************************************/
#ifndef STATFS_H
#define STATFS_H
#include <unistd.h>
#include <string.h>
#include <sys/stat.h>
#include <dirent.h>
#include <string>
#include <algorithm>
namespace statfs
{
using namespace std;
enum FILETYPE
{
ISDIR,
ISFIFO,
ISCHR,			// character file
ISBLK,			// block file
ISREG,			// regular file
ISUNKNOWN		// unknown 
};
class Statfs
{
public:
	/*
	 * @brief judge whether a process have permission to the file
	 * @path the full path of targeted file
	 * @perm the combination of rwx "r" -- read "w" -- write "x" -- execute
	 * such as "rx" "rxw" "wr" "rwx" and so on 
	 * @return true if read is ok
	 * */
	static bool Permit(const string &path, const string &perm);
	/*
	 * @brief get the size of file
	 * */
	static off_t FileSize(const string &path);
	/*
	 * @brief get the size of dir
	 * */
	static off_t DirSize(const string &path);
	/*
	 * @brief get the type of file
	 * */
	static FILETYPE FileType(const string &path);
};
}
#endif

/****************************************************************************
@File Name: statfs.cpp
@Author: wangzhicheng
@mail: 2363702560@qq.com
@Created Time: Tue 28 Feb 2017 05:15:08 PM CST
			   2017-03-01
****************************************************************************/
#include "statfs.h"
namespace statfs
{

bool Statfs::Permit(const string &path, const string &perm)
{
	struct stat buf;
	bool perms[3] = {0};
	bool permits[3] = {0};
	const static mode_t user_modes[3] = {S_IRUSR, S_IWUSR, S_IXUSR};
	const static mode_t group_modes[3] = {S_IRGRP, S_IWGRP, S_IXGRP};
	const static mode_t other_modes[3] = {S_IROTH, S_IWOTH, S_IXOTH};
	if(perm.size() > 3 || perm.size() <= 0) return false;		
	if(stat(path.c_str(), &buf)) return false;
	if(!getuid()) return true;			// root 
	// get the permissions from the perm argument
	for_each(begin(perm), end(perm), [&perms](char ch)
	{
		switch(ch)
		{
		case 'r':
		case 'R':
			if(!perms[0]) perms[0] = true;
			break;
		case 'w':
		case 'W':
			if(!perms[1]) perms[1] = true;
			break;
		case 'x':
		case 'X':
			if(!perms[2]) perms[2] = true;
			break;
		}
	});
	// check the buf and update permits
	for(int i = 0;i < 3;i++)
	{
		
		if(!perms[i]) continue;		
		if(buf.st_uid == geteuid())
		{
			permits[i] = buf.st_mode & user_modes[i];
			continue;
		}
		if(buf.st_gid == getegid())  
		{
			permits[i] = buf.st_mode & group_modes[i];
			continue;
		}
		permits[i] = buf.st_mode & S_IROTH;
	}
	// judge
	for(int i = 0;i < 3;i++)
	{
		if(!perms[i]) continue;		
		if(!permits[i]) return false;
	}

	return true;
}
/*
 * @brief get the size of file
 * */
off_t Statfs::FileSize(const string &path)
{
	struct stat buf;  
	if(stat(path.c_str(), &buf)) return -1;

	return buf.st_size;  
}
/*
 * @brief get the type of file
 * */
FILETYPE Statfs::FileType(const string &path)
{
	struct stat buf;  
	if(stat(path.c_str(), &buf)) return ISUNKNOWN;
	if(S_ISDIR(buf.st_mode)) return ISDIR;
	if(S_ISREG(buf.st_mode)) return ISREG;
	if(S_ISFIFO(buf.st_mode)) return ISFIFO;
	if(S_ISCHR(buf.st_mode)) return ISCHR;  
	if(S_ISBLK(buf.st_mode)) return ISBLK;

	return ISUNKNOWN;  
}
/*
 * @brief get the size of dir
 * */
off_t Statfs::DirSize(const string &path)
{
	off_t total = 0;
	DIR *dp = nullptr;
	struct dirent *dirp = nullptr;
	string newpath;
	static const string STR = "/"; 
	if(!(dp = opendir(path.c_str()))) 
	{
		closedir(dp);
		return 0;
	}
	while((dirp = readdir(dp))) 
	{
		if(!strcmp(dirp->d_name, ".") || !strcmp(dirp->d_name, "..")) continue;
		// generate a new path
		newpath = path;
		if('/' != newpath[newpath.size() - 1]) newpath += STR;		// judge the last character
		newpath += dirp->d_name;
		// is directory
		if(ISDIR == Statfs::FileType(newpath))													
		{
			total += DirSize(newpath);
		}
		else
		{
			total += FileSize(newpath);
		}
	}

	return total;
}
}

/****************************************************************************
@File Name: test.cpp
@Author: wangzhicheng
@mail: 2363702560@qq.com
@Created Time: Tue 28 Feb 2017 05:37:13 PM CST
			  2017-03-01
****************************************************************************/
#include "statfs.h"
#include <iostream>
using namespace statfs;
int main()
{
//	setuid(1000);
//	cout << Statfs::Permit("/var/log/TrendMicro/SProtectLinux/System.20170218.0001", "rxw") << endl;
//	cout << Statfs::FileSize("/var/log/TrendMicro/SProtectLinux/System.20170218.0001") << endl;
//	cout << Statfs::FileSize("/opt/TrendMicro/SProtectLinux/Product.ini") << endl;
//	cout << Statfs::FileType("/opt") << endl;
	cout << Statfs::DirSize("/opt") << endl;

	return 0;
}