src/t_dir_offset.c

   1
   2 #include <fcntl.h>
   3 #include <stdio.h>
   4 #include <unistd.h>
   5 #include <stdint.h>
   6 #include <stdlib.h>
   7 #include <sys/stat.h>
   8 #include <sys/syscall.h>
   9
  10 struct linux_dirent64 {
  11         uint64_t        d_ino;
  12         int64_t         d_off;
  13         unsigned short  d_reclen;
  14         unsigned char   d_type;
  15         char            d_name[0];
  16 };
  17
  18
  19 #define BUF_SIZE 4096
  20
  21 int
  22 main(int argc, char *argv[])
  23 {
  24         int fd, nread;
  25         char buf[BUF_SIZE];
  26         struct linux_dirent64 *d;
  27         int bpos;
  28
  29         fd = open(argv[1], O_RDONLY | O_DIRECTORY);
  30         if (fd < 0) {
  31                 perror("open");
  32                 exit(EXIT_FAILURE);
  33         }
  34
  35         for ( ; ; ) {
  36                 nread = syscall(SYS_getdents64, fd, buf, BUF_SIZE);
  37                 if (nread == -1) {
  38                         perror("getdents");
  39                         exit(EXIT_FAILURE);
  40                 }
  41
  42                 if (nread == 0)
  43                         break;
  44
  45                 for (bpos = 0; bpos < nread;) {
  46                         d = (struct linux_dirent64 *) (buf + bpos);
  47                         /*
  48                          * Can't use off_t here xfsqa is compiled with
  49                          * -D_FILE_OFFSET_BITS=64
  50                          */
  51                         if (d->d_off != (long)d->d_off) {
  52                                 fprintf(stderr, "detected d_off truncation "
  53                                                 "d_name = %s, d_off = %lld\n",
  54                                                 d->d_name, (long long)d->d_off);
  55                                 exit(EXIT_FAILURE);
  56                         }
  57                         bpos += d->d_reclen;
  58                 }
  59         }
  60
  61         exit(EXIT_SUCCESS);
  62 }