io/tst-readlinkat.c

   1 #include <dirent.h>
   2 #include <fcntl.h>
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5 #include <string.h>
   6 #include <unistd.h>
   7 #include <sys/stat.h>
   8
   9
  10 static void prepare (void);
  11 #define PREPARE(argc, argv) prepare ()
  12
  13 static int do_test (void);
  14 #define TEST_FUNCTION do_test ()
  15
  16 #include "../test-skeleton.c"
  17
  18 static int dir_fd;
  19
  20 static void
  21 prepare (void)
  22 {
  23   size_t test_dir_len = strlen (test_dir);
  24   static const char dir_name[] = "/tst-symlinkat.XXXXXX";
  25
  26   size_t dirbuflen = test_dir_len + sizeof (dir_name);
  27   char *dirbuf = malloc (dirbuflen);
  28   if (dirbuf == NULL)
  29     {
  30       puts ("out of memory");
  31       exit (1);
  32     }
  33
  34   snprintf (dirbuf, dirbuflen, "%s%s", test_dir, dir_name);
  35   if (mkdtemp (dirbuf) == NULL)
  36     {
  37       puts ("cannot create temporary directory");
  38       exit (1);
  39     }
  40
  41   add_temp_file (dirbuf);
  42
  43   dir_fd = open (dirbuf, O_RDONLY | O_DIRECTORY);
  44   if (dir_fd == -1)
  45     {
  46       puts ("cannot open directory");
  47       exit (1);
  48     }
  49 }
  50
  51
  52 static int
  53 do_test (void)
  54 {
  55   /* fdopendir takes over the descriptor, make a copy.  */
  56   int dupfd = dup (dir_fd);
  57   if (dupfd == -1)
  58     {
  59       puts ("dup failed");
  60       return 1;
  61     }
  62   if (lseek (dupfd, 0, SEEK_SET) != 0)
  63     {
  64       puts ("1st lseek failed");
  65       return 1;
  66     }
  67
  68   /* The directory should be empty safe the . and .. files.  */
  69   DIR *dir = fdopendir (dupfd);
  70   if (dir == NULL)
  71     {
  72       puts ("fdopendir failed");
  73       return 1;
  74     }
  75   struct dirent64 *d;
  76   while ((d = readdir64 (dir)) != NULL)
  77     if (strcmp (d->d_name, ".") != 0 && strcmp (d->d_name, "..") != 0)
  78       {
  79         printf ("temp directory contains file \"%s\"\n", d->d_name);
  80         return 1;
  81       }
  82   closedir (dir);
  83
  84   static const char symlinkcontent[] = "some-file";
  85   if (symlinkat (symlinkcontent, dir_fd, "another-file") != 0)
  86     {
  87       puts ("symlinkat failed");
  88       return 1;
  89     }
  90
  91   struct stat64 st2;
  92   if (fstatat64 (dir_fd, "another-file", &st2, AT_SYMLINK_NOFOLLOW) != 0)
  93     {
  94       puts ("fstatat64 failed");
  95       return 1;
  96     }
  97   if (!S_ISLNK (st2.st_mode))
  98     {
  99       puts ("2nd fstatat64 does not show file is a symlink");
 100       return 1;
 101     }
 102
 103   if (fstatat64 (dir_fd, symlinkcontent, &st2, AT_SYMLINK_NOFOLLOW) == 0)
 104     {
 105       puts ("2nd fstatat64 succeeded");
 106       return 1;
 107     }
 108
 109   char buf[100];
 110   int n = readlinkat (dir_fd, "another-file", buf, sizeof (buf));
 111   if (n == -1)
 112     {
 113       puts ("readlinkat failed");
 114       return 1;
 115     }
 116   if (n != sizeof (symlinkcontent) - 1)
 117     {
 118       printf ("readlinkat returned %d, expected %zu\n",
 119               n, sizeof (symlinkcontent) - 1);
 120       return 1;
 121     }
 122   if (strncmp (buf, symlinkcontent, n) != 0)
 123     {
 124       puts ("readlinkat retrieved wrong link content");
 125       return 1;
 126     }
 127
 128   if (unlinkat (dir_fd, "another-file", 0) != 0)
 129     {
 130       puts ("unlinkat failed");
 131       return 1;
 132     }
 133
 134   close (dir_fd);
 135
 136   return 0;
 137 }