c语言获取linux下cpu、mem、disk信息

linux下的路径：
cpu： /proc/stat
mem： /proc/meminfo

#define   _ULL   unsigned   long   long
#define   SET_IF_DESIRED(x,y)     if(x)   *(x)   =   (y)

static int five_cpu_numbers(_ULL* uret, _ULL* nret, _ULL* sret, _ULL* iret,
	_ULL* iowait)
{
	static _ULL u = 0, m = 0, s = 0, i = 0, iw = 0;
	_ULL user_j, nice_j, sys_j, idle_j, iowait_j = 0;
	FILE* fp;
	uint16_t byte_read;
	char buffer[100];

	fp = fopen("/proc/stat", "r");
	byte_read = fread(buffer, 1, sizeof(buffer) - 1, fp);
	fclose(fp);

	if (byte_read == 0 || byte_read == sizeof(buffer))
		return -1;
	buffer[byte_read] = '\0';

	sscanf(buffer, "cpu   %Lu   %Lu   %Lu   %Lu   %Lu", &user_j, &nice_j,
		&sys_j, &idle_j, &iowait_j);
	SET_IF_DESIRED(uret, user_j - u);
	SET_IF_DESIRED(nret, nice_j - m);
	SET_IF_DESIRED(sret, sys_j - s);
	/*   Idle   can   go   backwards   one   tick   due   to   kernel   calculation   issues   */
	SET_IF_DESIRED(iret, (idle_j > i) ? (idle_j - i) : 0);
	SET_IF_DESIRED(iowait, iowait_j - iw);
	u = user_j;
	m = nice_j;
	s = sys_j;
	i = idle_j;
	iw = iowait_j;

	return 0;
}

/*
 *   get   the   cpu   usage
 */
float get_cpu_used()
{
	float cpu_usage;
	_ULL user_j, nice_j, sys_j, idle_j, iowait_j = 0;

	if (five_cpu_numbers(&user_j, &nice_j, &sys_j, &idle_j, &iowait_j) != 0)
		return -1;
	usleep(500000);
	if (five_cpu_numbers(&user_j, &nice_j, &sys_j, &idle_j, &iowait_j) != 0)
		return -1;
	usleep(500000);
	if (five_cpu_numbers(&user_j, &nice_j, &sys_j, &idle_j, &iowait_j) != 0)
		return -1;

	cpu_usage = (idle_j * 100.0)
		/ (user_j + nice_j + sys_j + idle_j + iowait_j);

	if (cpu_usage > 100)
		cpu_usage = 100.0;

	/*   change   to   useage   */
	cpu_usage = 100.0 - (cpu_usage);

	return cpu_usage;
}

uint32_t get_mem_used()
{
	FILE* fd;
	int n;
	unsigned long mem_total, mem_used_rate, mem_fee;
	char buff[256], tmp[20];
	fd = fopen("/proc/meminfo", "r");
	fgets(buff, sizeof(buff), fd);
	sscanf(buff, "%s %lu %s\n", tmp, &mem_total, tmp);
	fgets(buff, sizeof(buff), fd);
	sscanf(buff, "%s %lu %s\n", tmp, &mem_fee, tmp);
	mem_used_rate = mem_total - mem_fee;
	mem_used_rate = mem_used_rate * 100 / mem_total;
	fclose(fd);

	return mem_used_rate;
}

void linux_srv_info()
{
	float cpu_usage, cpu_used;
	cpu_used = get_cpu_used();
	printf("cpu:%.f\n", cpu_used);
	
	printf("mem:%d\n", get_mem_used());

	char disk_path[3][10] = { "/","/dev","/var" };
	for (int i = 0; i < 3; i++)//根据磁盘路径(free -h 最后一列)来查询磁盘信息
	{
		char cmd[100] = { 0 };
		char name[20] = { 0 };
		char total[20] = { 0 };
		char used[20] = { 0 };

		/*sprintf(cmd, "df -h %s| grep %s| awk '{print $1,$2,$3}'", disk_path[i], disk_path[i]);
		FILE* fp = popen(cmd, "r");
		int ret = fscanf(fp, "%s %s %s", name, total, used);
		pclose(fp);
		printf("disk:%s %s %s\n", name, total, used);*/
		struct statfs sfs = {0};
		int ret = statfs(disk_path[i], &sfs);//路径必须为磁盘的路径,不是磁盘名。df -h最后一个参数
		int percent = (sfs.f_blocks - sfs.f_bfree) * 100 / (sfs.f_blocks - sfs.f_bfree + sfs.f_bavail + 1);
		printf("disk: %ld %ld %ld %d%% /home\n", 4 * sfs.f_blocks, 4 * (sfs.f_blocks - sfs.f_bfree), 4 * sfs.f_bavail, percent);
	}
}