Commande df facile sur Linux

Créez simplement la commande df en utilisant statfs (). Vous pouvez également utiliser statvfs (). N'utilisez pas setmntent () et endmntent () car le contenu est fopen () / fclose () Mais / etc / mtab Puis-je le voir directement?

Quelle est l'essence de l'élimination des pièces hautes performances telles que l'option lisible par l'homme et l'option d'exclusion?

df.c

#include <mntent.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/vfs.h>
#include <unistd.h>

typedef struct _df_t {
   struct mntent* mnt;
   struct statfs* fs;
} DfData;

int get_mount_record(FILE* mtab, DfData* df)
{
  df->mnt = getmntent(mtab);
  if (df->mnt) {
    if (df->mnt->mnt_dir == NULL) return 0;
    if (statfs(df->mnt->mnt_dir, df->fs) != 0) return 0;
    return 1;
  }
  return 0;
}

#define DF_KILO_RECORD_FMT  "%-25s %10lu %10lu %10lu %4s %-10s\n"

void print_kilobyte(DfData* df) {
  size_t total_size = df->fs->f_blocks * df->fs->f_bsize / 1024;
  size_t avail_size = df->fs->f_bavail * df->fs->f_bsize / 1024;
  size_t used_size = total_size - avail_size;
  char percent[4] = {0};
  if (df->fs->f_blocks == 0)
     snprintf(percent, sizeof(percent), "-");
  else
     snprintf(percent, sizeof(percent), "%lu%%", (100 * used_size / total_size));

  printf(DF_KILO_RECORD_FMT, df->mnt->mnt_fsname, total_size, used_size, avail_size, percent, df->mnt->mnt_dir);
  return;
}

void show_kilobyte(FILE* mtab) {
  DfData* df = (DfData*)malloc(sizeof(DfData));
  df->fs = (struct statfs *)malloc(sizeof(struct statfs));

  while(get_mount_record(mtab, df))
       print_kilobyte(df);

  free(df->fs);
  free(df);
  return;
}

int main(void)
{
  FILE* mtab = setmntent(_PATH_MOUNTED, "r");
  show_kilobyte(mtab);
  endmntent(mtab);
  exit(0);
}

Résultat de l'exécution.

$ gcc -Wall -Wextra -O2 df.o -o df
$ ./df
rootfs                      30909700   19431160   11478540  62% /
sysfs                              0          0          0    - /sys
proc                               0          0          0    - /proc
devtmpfs                     2441664          0    2441664   0% /dev
securityfs                         0          0          0    - /sys/kernel/security
tmpfs                        2325352          0    2325352   0% /dev/shm
devpts                             0          0          0    - /dev/pts
tmpfs                        2325352       8676    2316676   0% /run
tmpfs                        2325352          0    2325352   0% /sys/fs/cgroup
cgroup                             0          0          0    - /sys/fs/cgroup/systemd
pstore                             0          0          0    - /sys/fs/pstore
cgroup                             0          0          0    - /sys/fs/cgroup/cpuset
cgroup                             0          0          0    - /sys/fs/cgroup/pids
cgroup                             0          0          0    - /sys/fs/cgroup/net_cls,net_prio
cgroup                             0          0          0    - /sys/fs/cgroup/blkio
cgroup                             0          0          0    - /sys/fs/cgroup/perf_event
cgroup                             0          0          0    - /sys/fs/cgroup/devices
cgroup                             0          0          0    - /sys/fs/cgroup/freezer
cgroup                             0          0          0    - /sys/fs/cgroup/hugetlb
cgroup                             0          0          0    - /sys/fs/cgroup/cpu,cpuacct
cgroup                             0          0          0    - /sys/fs/cgroup/memory
configfs                           0          0          0    - /sys/kernel/config
/dev/mapper/centos-root     30909700   19431160   11478540  62% /
systemd-1                          0          0          0    - /proc/sys/fs/binfmt_misc
mqueue                             0          0          0    - /dev/mqueue
hugetlbfs                          0          0          0    - /dev/hugepages
debugfs                            0          0          0    - /sys/kernel/debug
binfmt_misc                        0          0          0    - /proc/sys/fs/binfmt_misc
nfsd                               0          0          0    - /proc/fs/nfsd
/dev/xvda1                    508588     296336     212252  58% /boot
sunrpc                             0          0          0    - /var/lib/nfs/rpc_pipefs
none                               0          0          0    - /proc/xen
tmpfs                         465072          0     465072   0% /run/user/1000