64 lines
2.6 KiB
C
64 lines
2.6 KiB
C
/* Internals for openat-like functions.
|
|
|
|
Copyright (C) 2005-2006, 2009-2022 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 <https://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 */
|