ディスクの空き容量を調べる

diskfree.c

// diskfree.c
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/statvfs.h>

// 空き容量を求める
int diskfree(char *path)
{
	int ret = 0;
	struct statvfs buf = {0};
	
	ret = statvfs(path, &buf);
	if (ret != 0) {
		printf("Error: statvfs() %s: %s\n", strerror(errno), path);
		return(-1);
	}
	
	unsigned long long allsize = (long long)buf.f_blocks * (long long)buf.f_bsize / (1000 * 1000);
	unsigned long long freesize = (long long)buf.f_bfree * (long long)buf.f_bsize / (1000 * 1000);
	unsigned long long usedsize = allsize - freesize;
	
	printf("path=%s, f_bsize=%lu, f_frsize=%lu, f_blocks=%lu, f_bfree=%lu, f_files=%lu, f_ffree=%lu, f_fsid=%lu, f_flag=%lu, f_namemax=%lu\n", 
		path, buf.f_bsize, buf.f_frsize, (unsigned long)buf.f_blocks, (unsigned long)buf.f_bfree, (unsigned long)buf.f_files, (unsigned long)buf.f_ffree, buf.f_fsid, buf.f_flag, buf.f_namemax);
	
	printf("パス\t\t全容量\t\t使用\t\t使用可\t\t使用%%\n");
	printf("%s\t\t%lluMB\t\t%lluMB\t\t%lluMB\t\t%2.1f%%\n", path, allsize, usedsize, freesize, (((float)usedsize / (float)allsize) * 100.0));

	return(0);
}

// メイン
int main(int argc, char *argv[])
{
	int ret = 0;
	
	// 引数チェック
	if (argc != 2) {
		fprintf(stderr, "diskfree: no input path\n");
		exit(EXIT_FAILURE);
	}
	
	// 空き容量を求める
	ret = diskfree(argv[1]);
	if (ret != 0) exit(EXIT_FAILURE);
	
	exit(EXIT_SUCCESS);
}

Makefile

#Makefile
diskfree: diskfree.c
	g++ -o diskfree diskfree.c
clean:
	rm -f diskfree