tests/test-readlinkat.c

   1 /* Tests of readlinkat.
   2    Copyright (C) 2009-2020 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 #include <config.h>
  20
  21 #include <unistd.h>
  22
  23 #include "signature.h"
  24 SIGNATURE_CHECK (readlinkat, ssize_t, (int, char const *, char *, size_t));
  25
  26 #include <fcntl.h>
  27 #include <errno.h>
  28 #include <stdbool.h>
  29 #include <stdio.h>
  30 #include <stdlib.h>
  31 #include <string.h>
  32 #include <sys/stat.h>
  33
  34 #include "ignore-value.h"
  35 #include "macros.h"
  36
  37 #ifndef HAVE_SYMLINK
  38 # define HAVE_SYMLINK 0
  39 #endif
  40
  41 #define BASE "test-readlinkat.t"
  42
  43 #include "test-readlink.h"
  44
  45 static int dfd = AT_FDCWD;
  46
  47 static ssize_t
  48 do_readlink (char const *name, char *buf, size_t len)
  49 {
  50   return readlinkat (dfd, name, buf, len);
  51 }
  52
  53 int
  54 main (void)
  55 {
  56   char buf[80];
  57   int result;
  58
  59   /* Remove any leftovers from a previous partial run.  */
  60   ignore_value (system ("rm -rf " BASE "*"));
  61
  62   /* Test behaviour for invalid file descriptors.  */
  63   {
  64     errno = 0;
  65     ASSERT (readlinkat (-1, "foo", buf, sizeof buf) == -1);
  66     ASSERT (errno == EBADF);
  67   }
  68   {
  69     close (99);
  70     errno = 0;
  71     ASSERT (readlinkat (99, "foo", buf, sizeof buf) == -1);
  72     ASSERT (errno == EBADF);
  73   }
  74
  75   /* Perform same checks as counterpart functions.  */
  76   result = test_readlink (do_readlink, false);
  77   dfd = openat (AT_FDCWD, ".", O_RDONLY);
  78   ASSERT (0 <= dfd);
  79   ASSERT (test_readlink (do_readlink, false) == result);
  80
  81   /* Now perform some cross-directory checks.  Skip everything else on
  82      mingw.  */
  83   if (HAVE_SYMLINK)
  84     {
  85       const char *contents = "don't matter!";
  86       ssize_t exp = strlen (contents);
  87
  88       /* Create link while cwd is '.', then read it in '..'.  */
  89       ASSERT (symlinkat (contents, AT_FDCWD, BASE "link") == 0);
  90       errno = 0;
  91       ASSERT (symlinkat (contents, dfd, BASE "link") == -1);
  92       ASSERT (errno == EEXIST);
  93       ASSERT (chdir ("..") == 0);
  94       errno = 0;
  95       ASSERT (readlinkat (AT_FDCWD, BASE "link", buf, sizeof buf) == -1);
  96       ASSERT (errno == ENOENT);
  97       ASSERT (readlinkat (dfd, BASE "link", buf, sizeof buf) == exp);
  98       ASSERT (strncmp (contents, buf, exp) == 0);
  99       ASSERT (unlinkat (dfd, BASE "link", 0) == 0);
 100
 101       /* Create link while cwd is '..', then read it in '.'.  */
 102       ASSERT (symlinkat (contents, dfd, BASE "link") == 0);
 103       ASSERT (fchdir (dfd) == 0);
 104       errno = 0;
 105       ASSERT (symlinkat (contents, AT_FDCWD, BASE "link") == -1);
 106       ASSERT (errno == EEXIST);
 107       buf[0] = '\0';
 108       ASSERT (readlinkat (AT_FDCWD, BASE "link", buf, sizeof buf) == exp);
 109       ASSERT (strncmp (contents, buf, exp) == 0);
 110       buf[0] = '\0';
 111       ASSERT (readlinkat (dfd, BASE "link", buf, sizeof buf) == exp);
 112       ASSERT (strncmp (contents, buf, exp) == 0);
 113       ASSERT (unlink (BASE "link") == 0);
 114     }
 115
 116   ASSERT (close (dfd) == 0);
 117   if (result == 77)
 118     fputs ("skipping test: symlinks not supported on this file system\n",
 119            stderr);
 120   return result;
 121 }