tests/test-readlink.h

   1 /* Tests of readlink.
   2    Copyright (C) 2009-2021 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 /* Written by Eric Blake <ebb9@byu.net>, 2009.  */
  18
  19 /* This file is designed to test both readlink(a,b,c) and
  20    readlinkat(AT_FDCWD,a,b,c).  FUNC is the function to test.  Assumes
  21    that BASE and ASSERT are already defined, and that appropriate
  22    headers are already included.  If PRINT, warn before skipping
  23    symlink tests with status 77.  */
  24
  25 static int
  26 test_readlink (ssize_t (*func) (char const *, char *, size_t), bool print)
  27 {
  28   char buf[80];
  29
  30   /* Sanity checks of failures.  Mingw lacks symlink, but readlink can
  31      still distinguish between various errors.  */
  32   memset (buf, 0xff, sizeof buf);
  33   errno = 0;
  34   ASSERT (func ("no_such", buf, sizeof buf) == -1);
  35   ASSERT (errno == ENOENT);
  36   errno = 0;
  37   ASSERT (func ("no_such/", buf, sizeof buf) == -1);
  38   ASSERT (errno == ENOENT);
  39   errno = 0;
  40   ASSERT (func ("", buf, sizeof buf) == -1);
  41   ASSERT (errno == ENOENT || errno == EINVAL);
  42   errno = 0;
  43   ASSERT (func (".", buf, sizeof buf) == -1);
  44   ASSERT (errno == EINVAL);
  45   errno = 0;
  46   ASSERT (func ("./", buf, sizeof buf) == -1);
  47   ASSERT (errno == EINVAL);
  48   ASSERT (close (creat (BASE "file", 0600)) == 0);
  49   errno = 0;
  50   ASSERT (func (BASE "file", buf, sizeof buf) == -1);
  51   ASSERT (errno == EINVAL);
  52   errno = 0;
  53   ASSERT (func (BASE "file/", buf, sizeof buf) == -1);
  54   ASSERT (errno == ENOTDIR || errno == EINVAL); /* AIX yields EINVAL */
  55
  56   /* Now test actual symlinks.  */
  57   if (symlink (BASE "dir", BASE "link"))
  58     {
  59       ASSERT (unlink (BASE "file") == 0);
  60       if (print)
  61         fputs ("skipping test: symlinks not supported on this file system\n",
  62                stderr);
  63       return 77;
  64     }
  65   ASSERT (mkdir (BASE "dir", 0700) == 0);
  66   errno = 0;
  67   ASSERT (func (BASE "link/", buf, sizeof buf) == -1);
  68   ASSERT (errno == EINVAL);
  69   ASSERT (symlink (BASE "link", BASE "link2") == 0);
  70   errno = 0;
  71   ASSERT (func (BASE "link2/", buf, sizeof buf) == -1);
  72   ASSERT (errno == EINVAL);
  73   ASSERT (unlink (BASE "link2") == 0);
  74   ASSERT (symlink (BASE "file", BASE "link2") == 0);
  75   errno = 0;
  76   ASSERT (func (BASE "link2/", buf, sizeof buf) == -1);
  77   ASSERT (errno == ENOTDIR || errno == EINVAL); /* AIX yields EINVAL */
  78   ASSERT (unlink (BASE "file") == 0);
  79   ASSERT (unlink (BASE "link2") == 0);
  80   {
  81     /* Up till now, no readlink has been successful, so buf should be
  82        unchanged.  */
  83     int i;
  84     for (i = 0; i < sizeof buf; i++)
  85       ASSERT (buf[i] == (char) 0xff);
  86   }
  87   {
  88     size_t len = strlen (BASE "dir");
  89     /* When passing too small of a buffer, expect the truncated
  90        length, or an ERANGE failure.  However, a size of 0 is not
  91        portable enough to test.  */
  92     ssize_t result;
  93     errno = 0;
  94     result = readlink (BASE "link", buf, 1);
  95     if (result == -1)
  96       {
  97         ASSERT (errno == ERANGE);
  98         ASSERT (buf[0] == (char) 0xff);
  99       }
 100     else
 101       {
 102         ASSERT (result == 1);
 103         ASSERT (buf[0] == BASE[0]);
 104       }
 105     ASSERT (buf[1] == (char) 0xff);
 106     ASSERT (func (BASE "link", buf, len) == len);
 107     ASSERT (strncmp (buf, BASE "dir", len) == 0);
 108     ASSERT (buf[len] == (char) 0xff);
 109     ASSERT (func (BASE "link", buf, sizeof buf) == len);
 110     ASSERT (strncmp (buf, BASE "dir", len) == 0);
 111     /* POSIX says rest of buf is unspecified; but in practice, it is
 112        either left alone, or NUL-terminated.  */
 113     ASSERT (buf[len] == '\0' || buf[len] == (char) 0xff);
 114   }
 115   ASSERT (rmdir (BASE "dir") == 0);
 116   ASSERT (unlink (BASE "link") == 0);
 117
 118   return 0;
 119 }