1  /* Test to verify that realpath() doesn't cause false positives due
       2     to GCC attribute malloc.
       3  
       4     Test failure exposes the presence of the attribute in the following
       5     declaration:
       6  
       7     __attribute__ ((__malloc__ (free, 1))) char*
       8     realpath (const char *, char *);
       9  
      10     Copyright (C) 2021-2023 Free Software Foundation, Inc.
      11     This file is part of the GNU C Library.
      12  
      13     The GNU C Library is free software; you can redistribute it and/or
      14     modify it under the terms of the GNU Lesser General Public
      15     License as published by the Free Software Foundation; either
      16     version 2.1 of the License, or (at your option) any later version.
      17  
      18     The GNU C Library is distributed in the hope that it will be useful,
      19     but WITHOUT ANY WARRANTY; without even the implied warranty of
      20     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      21     Lesser General Public License for more details.
      22  
      23     You should have received a copy of the GNU Lesser General Public
      24     License along with the GNU C Library; if not, see
      25     <https://www.gnu.org/licenses/>.  */
      26  
      27  #include <stdio.h>
      28  #include <stdlib.h>
      29  #include <malloc.h>
      30  
      31  #if defined __GNUC__ && __GNUC__ >= 11
      32  /* Turn GCC -Wmismatched-dealloc warnings into errors to expose false
      33     positives.  */
      34  #  pragma GCC diagnostic push
      35  #  pragma GCC diagnostic error "-Wmismatched-dealloc"
      36  
      37  /* Associate dealloc as the only deallocator suitable for pointers
      38     returned from alloc.
      39     GCC automatically disables inlining of allocator and deallocator
      40     functions marked with the argument form of attribute malloc but
      41     it doesn't hurt to disable it explicitly.  */
      42  __attribute  ((noipa)) void dealloc (void *);
      43  __attribute ((malloc (dealloc, 1))) char* alloc (void);
      44  #endif
      45  
      46  void dealloc (void *p)
      47  {
      48    free (p);
      49  }
      50  
      51  char* alloc (void)
      52  {
      53    return (char *)malloc (8);
      54  }
      55  
      56  static int
      57  do_test (void)
      58  {
      59    char *resolved_path = alloc ();
      60    char *ret = realpath ("/", resolved_path);
      61    dealloc (ret);
      62  
      63    resolved_path = alloc ();
      64    ret = realpath ("/", resolved_path);
      65    dealloc (resolved_path);
      66  
      67    /* The following should emit a warning (but doesn't with GCC 11):
      68       resolved_path = alloc ();
      69       ret = realpath ("/", resolved_path);
      70       free (ret);   // expect -Wmismatched-dealloc
      71    */
      72  
      73    return 0;
      74  }
      75  
      76  #if defined __GNUC__ && __GNUC__ >= 11
      77  /* Restore -Wmismatched-dealloc setting.  */
      78  #  pragma GCC diagnostic pop
      79  #endif
      80  
      81  #define TEST_FUNCTION do_test ()
      82  #include "../test-skeleton.c"