kc3-lang/gnulib/lib/openat-priv.h

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• Hash : 03dd3ccd
  Author :
  Date : 2011-01-11T10:26:56
  

  openat: Increase OPENAT_BUFFER_SIZE from 512 to at least 1024
  
  This avoids heap allocation for file names whose lengths are in
  the range 512..1023, with the upper bound increasing to at most
  4031 depending on the platform's PATH_MAX.  (We do not want
  pathmax.h here as it might supply a non-constant PATH_MAX.)
  * lib/openat-priv.h (SAFER_ALLOCA_MAX, SAFER_ALLOCA): New macros.
  Perhaps they should be moved to malloca.h?
  (OPENAT_BUFFER_SIZE): Use them.
  

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• lib/openat-priv.h

• /* Internals for openat-like functions.
  
     Copyright (C) 2005-2006, 2009-2011 Free Software Foundation, Inc.
  
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
     the Free Software Foundation; either version 3 of the License, or
     (at your option) any later version.
  
     This program is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.
  
     You should have received a copy of the GNU General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  
  /* written by Jim Meyering */
  
  #ifndef _GL_HEADER_OPENAT_PRIV
  #define _GL_HEADER_OPENAT_PRIV
  
  #include <errno.h>
  #include <limits.h>
  #include <stdlib.h>
  
  /* Maximum number of bytes that it is safe to allocate as a single
     array on the stack, and that is known as a compile-time constant.
     The assumption is that we'll touch the array very quickly, or a
     temporary very near the array, provoking an out-of-memory trap.  On
     some operating systems, there is only one guard page for the stack,
     and a page size can be as small as 4096 bytes.  Subtract 64 in the
     hope that this will let the compiler touch a nearby temporary and
     provoke a trap.  */
  #define SAFER_ALLOCA_MAX (4096 - 64)
  
  #define SAFER_ALLOCA(m) ((m) < SAFER_ALLOCA_MAX ? (m) : SAFER_ALLOCA_MAX)
  
  #if defined PATH_MAX
  # define OPENAT_BUFFER_SIZE SAFER_ALLOCA (PATH_MAX)
  #elif defined _XOPEN_PATH_MAX
  # define OPENAT_BUFFER_SIZE SAFER_ALLOCA (_XOPEN_PATH_MAX)
  #else
  # define OPENAT_BUFFER_SIZE SAFER_ALLOCA (1024)
  #endif
  
  char *openat_proc_name (char buf[OPENAT_BUFFER_SIZE], int fd, char const *file);
  
  /* Trying to access a BUILD_PROC_NAME file will fail on systems without
     /proc support, and even on systems *with* ProcFS support.  Return
     nonzero if the failure may be legitimate, e.g., because /proc is not
     readable, or the particular .../fd/N directory is not present.  */
  #define EXPECTED_ERRNO(Errno)                   \
    ((Errno) == ENOTDIR || (Errno) == ENOENT      \
     || (Errno) == EPERM || (Errno) == EACCES     \
     || (Errno) == ENOSYS /* Solaris 8 */         \
     || (Errno) == EOPNOTSUPP /* FreeBSD */)
  
  /* Wrapper function shared among linkat and renameat.  */
  int at_func2 (int fd1, char const *file1,
                int fd2, char const *file2,
                int (*func) (char const *file1, char const *file2));
  
  #endif /* _GL_HEADER_OPENAT_PRIV */
  

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