src/t_dir_offset2.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2011 Gražvydas Ignotas
   4  */
   5
   6 /*
   7  * This test checks if no duplicate d_off values are returned and
   8  * that these offsets are seekable to entry with the right inode.
   9  */
  10
  11 #include <errno.h>
  12 #include <fcntl.h>
  13 #include <stdio.h>
  14 #include <unistd.h>
  15 #include <stdint.h>
  16 #include <stdlib.h>
  17 #include <string.h>
  18 #include <sys/stat.h>
  19 #include <sys/syscall.h>
  20
  21 struct linux_dirent64 {
  22         uint64_t        d_ino;
  23         uint64_t        d_off;
  24         unsigned short  d_reclen;
  25         unsigned char   d_type;
  26         char            d_name[0];
  27 };
  28
  29 #define BUF_SIZE 4096
  30 #define HISTORY_LEN 1024
  31
  32 static uint64_t d_off_history[HISTORY_LEN];
  33 static uint64_t d_ino_history[HISTORY_LEN];
  34
  35 void usage()
  36 {
  37         fprintf(stderr, "usage: t_dir_offset2: <dir> [[bufsize] [-|+]<filename> [-v]]\n");
  38         exit(EXIT_FAILURE);
  39 }
  40
  41 int main(int argc, char *argv[])
  42 {
  43         int fd, fd2 = -1;
  44         char buf[BUF_SIZE];
  45         int nread, bufsize = BUF_SIZE;
  46         struct linux_dirent64 *d;
  47         int bpos, total, i;
  48         off_t lret;
  49         int retval = EXIT_SUCCESS;
  50         const char *filename = NULL;
  51         int exists = 0, found = 0;
  52         int modify = 0, verbose = 0;
  53
  54         if (argc > 2) {
  55                 bufsize = atoi(argv[2]);
  56                 if (!bufsize)
  57                         usage();
  58                 if (bufsize > BUF_SIZE)
  59                         bufsize = BUF_SIZE;
  60
  61                 if (argc > 3) {
  62                         filename = argv[3];
  63                         /* +<filename> creates, -<filename> removes */
  64                         if (filename[0] == '+')
  65                                 modify = 1;
  66                         else if (filename[0] == '-')
  67                                 modify = -1;
  68                         if (modify)
  69                                 filename++;
  70                         if (argc > 4 && !strcmp(argv[4], "-v"))
  71                                 verbose = 1;
  72                 }
  73         } else if (argc < 2) {
  74                 usage();
  75         }
  76
  77         fd = open(argv[1], O_RDONLY | O_DIRECTORY);
  78         if (fd < 0) {
  79                 perror("open");
  80                 exit(EXIT_FAILURE);
  81         }
  82
  83         if (filename) {
  84                 exists = !faccessat(fd, filename, F_OK, AT_SYMLINK_NOFOLLOW);
  85                 if (!exists && errno != ENOENT) {
  86                         perror("faccessat");
  87                         exit(EXIT_FAILURE);
  88                 }
  89         }
  90
  91         total = 0;
  92         for ( ; ; ) {
  93                 nread = syscall(SYS_getdents64, fd, buf, bufsize);
  94                 if (nread == -1) {
  95                         perror("getdents");
  96                         exit(EXIT_FAILURE);
  97                 }
  98
  99                 if (modify && fd2 < 0 && total == 0) {
 100                         printf("getdents at offset 0 returned %d bytes\n", nread);
 101
 102                         /* create/unlink entry after first getdents */
 103                         if (modify > 0) {
 104                                 if (openat(fd, filename, O_CREAT, 0600) < 0) {
 105                                         perror("openat");
 106                                         exit(EXIT_FAILURE);
 107                                 }
 108                                 exists = 1;
 109                                 printf("created entry %s\n", filename);
 110                         } else if (modify < 0) {
 111                                 if (unlinkat(fd, filename, 0) < 0) {
 112                                         perror("unlinkat");
 113                                         exit(EXIT_FAILURE);
 114                                 }
 115                                 exists = 0;
 116                                 printf("unlinked entry %s\n", filename);
 117                         }
 118
 119                         /*
 120                          * Old fd may not return new entry and may return stale
 121                          * entries which is allowed.  Keep old fd open and open
 122                          * a new fd to check for stale or missing entries later.
 123                          */
 124                         fd2 = open(argv[1], O_RDONLY | O_DIRECTORY);
 125                         if (fd2 < 0) {
 126                                 perror("open fd2");
 127                                 exit(EXIT_FAILURE);
 128                         }
 129                 }
 130
 131                 if (nread == 0) {
 132                         if (fd2 < 0 || fd == fd2)
 133                                 break;
 134
 135                         /* Re-iterate with new fd leaving old fd open */
 136                         fd = fd2;
 137                         total = 0;
 138                         found = 0;
 139                         continue;
 140                 }
 141
 142                 if (nread == 0)
 143                         break;
 144
 145                 for (bpos = 0; bpos < nread; total++) {
 146                         d = (struct linux_dirent64 *) (buf + bpos);
 147
 148                         if (total >= HISTORY_LEN) {
 149                                 fprintf(stderr, "too many files\n");
 150                                 break;
 151                         }
 152
 153                         for (i = 0; i < total; i++)
 154                         {
 155                                 if (d_off_history[i] == d->d_off) {
 156                                         fprintf(stderr, "entries %d and %d have duplicate d_off %lld\n",
 157                                                 i, total, (long long int)d->d_off);
 158                                         retval = EXIT_FAILURE;
 159                                 }
 160                         }
 161                         d_off_history[total] = d->d_off;
 162                         d_ino_history[total] = d->d_ino;
 163                         if (filename) {
 164                                 if (verbose)
 165                                         printf("entry #%d: %s (d_ino=%lld, d_off=%lld)\n",
 166                                                i, d->d_name, (long long int)d->d_ino,
 167                                                (long long int)d->d_off);
 168                                 if (!strcmp(filename, d->d_name))
 169                                         found = 1;
 170                         }
 171                         bpos += d->d_reclen;
 172                 }
 173         }
 174
 175         if (filename) {
 176                 if (exists == found) {
 177                         printf("entry %s %sfound as expected\n", filename, found ? "" : "not ");
 178                 } else {
 179                         fprintf(stderr, "%s entry %s\n",
 180                                 exists ? "missing" : "stale", filename);
 181                         exit(EXIT_FAILURE);
 182                 }
 183         }
 184
 185         /* check if seek works correctly */
 186         d = (struct linux_dirent64 *)buf;
 187         for (i = total - 1; i >= 0; i--)
 188         {
 189                 lret = lseek(fd, i > 0 ? d_off_history[i - 1] : 0, SEEK_SET);
 190                 if (lret == -1) {
 191                         perror("lseek");
 192                         exit(EXIT_FAILURE);
 193                 }
 194
 195                 nread = syscall(SYS_getdents64, fd, buf, bufsize);
 196                 if (nread == -1) {
 197                         perror("getdents");
 198                         exit(EXIT_FAILURE);
 199                 }
 200
 201                 if (nread == 0) {
 202                         fprintf(stderr, "getdents returned 0 on entry %d\n", i);
 203                         retval = EXIT_FAILURE;
 204                 }
 205
 206                 if (d->d_ino != d_ino_history[i]) {
 207                         fprintf(stderr, "entry %d has inode %lld, expected %lld\n",
 208                                 i, (long long int)d->d_ino, (long long int)d_ino_history[i]);
 209                         retval = EXIT_FAILURE;
 210                 }
 211         }
 212
 213         close(fd);
 214         exit(retval);
 215 }