代码：
#include <stdio.h> #include <mntent.h> #include <string.h> #include <sys/vfs.h> static const unsigned long long G = 1024*1024*1024ull; static const unsigned long long M = 1024*1024; static const unsigned long long K = 1024; static char str[20]; char* kscale(unsigned long b, unsigned long bs) { unsigned long long size = b * (unsigned long long)bs; if (size > G) { sprintf(str, "%0.2f GB", size/(G*1.0)); return str; } else if (size > M) { sprintf(str, "%0.2f MB", size/(1.0*M)); return str; } else if (size > K) { sprintf(str, "%0.2f K", size/(1.0*K)); return str; } else { sprintf(str, "%0.2f B", size*1.0); return str; } } int main(int argc, char *argv[]) { FILE* mount_table; struct mntent *mount_entry; struct statfs s; unsigned long blocks_used; unsigned blocks_percent_used; const char *disp_units_hdr = NULL; mount_table = NULL; mount_table = setmntent("/etc/mtab", "r"); if (!mount_table) { fprintf(stderr, "set mount entry error "); return -1; } disp_units_hdr = " Size"; printf("Filesystem %-15sUsed Available %s Mounted on ", disp_units_hdr, "Use%"); while (1) { const char *device; const char *mount_point; if (mount_table) { mount_entry = getmntent(mount_table); if (!mount_entry) { endmntent(mount_table); break; } } else continue; device = mount_entry->mnt_fsname; mount_point = mount_entry->mnt_dir; //fprintf(stderr, "mount info: device=%s mountpoint=%s ", device, mount_point); if (statfs(mount_point, &s) != 0) { fprintf(stderr, "statfs failed! "); continue; } if ((s.f_blocks > 0) || !mount_table ) { blocks_used = s.f_blocks - s.f_bfree; blocks_percent_used = 0; if (blocks_used + s.f_bavail) { blocks_percent_used = (blocks_used * 100ULL + (blocks_used + s.f_bavail)/2 ) / (blocks_used + s.f_bavail); } /* GNU coreutils 6.10 skips certain mounts, try to be compatible. */ if (strcmp(device, "rootfs") == 0) continue; if (printf(" %-20s" + 1, device) > 20) printf(" %-20s", ""); char s1[20]; char s2[20]; char s3[20]; strcpy(s1, kscale(s.f_blocks, s.f_bsize)); strcpy(s2, kscale(s.f_blocks - s.f_bfree, s.f_bsize)); strcpy(s3, kscale(s.f_bavail, s.f_bsize)); printf(" %9s %9s %9s %3u%% %s ", s1, s2, s3, blocks_percent_used, mount_point); } } return 0; }
运行效果如下：
编译：g++ -g -Wall main.cpp 可以生成一个a.out的文件， 下面是运行a.out和df -h的输出对比： :/tmp/tmp$ df -h 文件系统 容量 已用 可用 已用% 挂载点 /dev/sda7 9.4G 6.5G 2.5G 73% / none 1.6G 300K 1.6G 1% /dev none 1.6G 212K 1.6G 1% /dev/shm none 1.6G 296K 1.6G 1% /var/run none 1.6G 0 1.6G 0% /var/lock none 1.6G 0 1.6G 0% /lib/init/rw /dev/sda6 113G 87G 26G 77% /media/work_ /dev/sda9 26G 23G 2.0G 92% /home /tmp/tmp$ ./a.out Filesystem Size Used Available Use% Mounted on /dev/sda7 9.39 GB 6.45 GB 2.46 GB 72% / none 1.59 GB 300.00 K 1.59 GB 0% /dev none 1.60 GB 1020.00 K 1.59 GB 0% /dev/shm none 1.60 GB 296.00 K 1.59 GB 0% /var/run none 1.60 GB 0.00 B 1.60 GB 0% /var/lock none 1.60 GB 0.00 B 1.60 GB 0% /lib/init/rw /dev/sda6 112.62 GB 86.67 GB 25.95 GB 77% /media/work_ /dev/sda9 25.38 GB 22.10 GB 1.99 GB 92% /home
专栏：
微信公众号 - MySQL数据库技术：
知乎 - 数据库技术 专栏：
https://zhuanlan.zhihu.com/mysqldb
博客：
思否/segmentfault 专栏：
https://segmentfault.com/u/dbtech
开源中国/oschina：
https://my.oschina.net/dbtech
掘金：
https://juejin.im/user/5e9d3ed251882538083fed1f/posts
博客园/cnblogs：
https://www.cnblogs.com/dbtech