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