tests/test-openat.c

   1 /* Test that openat works.
   2    Copyright (C) 2009-2025 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 <fcntl.h>
  22
  23 #include "signature.h"
  24 SIGNATURE_CHECK (openat, int, (int, char const *, int, ...));
  25
  26 #include <errno.h>
  27 #include <stdarg.h>
  28 #include <stdio.h>
  29 #include <unistd.h>
  30
  31 #include "macros.h"
  32
  33 #define BASE "test-openat.t"
  34
  35 #include "test-open.h"
  36
  37 static int dfd = AT_FDCWD;
  38
  39 /* Wrapper around openat to test open behavior.  */
  40 static int
  41 do_open (char const *name, int flags, ...)
  42 {
  43   if (flags & O_CREAT)
  44     {
  45       mode_t mode = 0;
  46       va_list arg;
  47       va_start (arg, flags);
  48
  49       /* We have to use PROMOTED_MODE_T instead of mode_t, otherwise GCC 4
  50          creates crashing code when 'mode_t' is smaller than 'int'.  */
  51       mode = va_arg (arg, PROMOTED_MODE_T);
  52
  53       va_end (arg);
  54       return openat (dfd, name, flags, mode);
  55     }
  56   return openat (dfd, name, flags);
  57 }
  58
  59 int
  60 main ()
  61 {
  62   int result;
  63
  64   /* Test behaviour for invalid file descriptors.  */
  65   {
  66     errno = 0;
  67     ASSERT (openat (-1, "foo", O_RDONLY) == -1);
  68     ASSERT (errno == EBADF);
  69   }
  70   {
  71     close (99);
  72     errno = 0;
  73     ASSERT (openat (99, "foo", O_RDONLY) == -1);
  74     ASSERT (errno == EBADF);
  75   }
  76
  77   /* Basic checks.  */
  78   result = test_open (do_open, false);
  79   dfd = open (".", O_RDONLY);
  80   ASSERT (0 <= dfd);
  81   ASSERT (test_open (do_open, false) == result);
  82   ASSERT (close (dfd) == 0);
  83
  84   /* Check that even when *-safer modules are in use, plain openat can
  85      land in fd 0.  Do this test last, since it is destructive to
  86      stdin.  */
  87   ASSERT (close (STDIN_FILENO) == 0);
  88   ASSERT (openat (AT_FDCWD, ".", O_RDONLY) == STDIN_FILENO);
  89   {
  90     dfd = open (".", O_RDONLY);
  91     ASSERT (STDIN_FILENO < dfd);
  92     ASSERT (chdir ("..") == 0);
  93     ASSERT (close (STDIN_FILENO) == 0);
  94     ASSERT (openat (dfd, ".", O_RDONLY) == STDIN_FILENO);
  95     ASSERT (close (dfd) == 0);
  96   }
  97   return (result ? result : test_exit_status);
  98 }