diff options
Diffstat (limited to 'lib/openat-priv.h')
| -rw-r--r-- | lib/openat-priv.h | 67 |
1 files changed, 38 insertions, 29 deletions
diff --git a/lib/openat-priv.h b/lib/openat-priv.h index 2d98821..ed763db 100644 --- a/lib/openat-priv.h +++ b/lib/openat-priv.h @@ -1,11 +1,11 @@ /* Internals for openat-like functions. - Copyright (C) 2005, 2006 Free Software Foundation, Inc. + Copyright (C) 2005-2006, 2009-2016 Free Software Foundation, Inc. - This program is free software; you can redistribute it and/or modify + 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 2, or (at your option) - any later version. + 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 @@ -13,43 +13,52 @@ 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, write to the Free Software Foundation, - Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ + 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> -#define OPENAT_BUFFER_SIZE 512 -char *openat_proc_name (char buf[OPENAT_BUFFER_SIZE], int fd, char const *file); +/* 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) -/* Some systems don't have ENOSYS. */ -#ifndef ENOSYS -# ifdef ENOTSUP -# define ENOSYS ENOTSUP -# else -/* Some systems don't have ENOTSUP either. */ -# define ENOSYS EINVAL -# endif -#endif +#define SAFER_ALLOCA(m) ((m) < SAFER_ALLOCA_MAX ? (m) : SAFER_ALLOCA_MAX) -/* Some systems don't have EOPNOTSUPP. */ -#ifndef EOPNOTSUPP -# ifdef ENOTSUP -# define EOPNOTSUPP ENOTSUP -# else -/* Some systems don't have ENOTSUP either. */ -# define EOPNOTSUPP EINVAL -# endif +#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 */ \ +#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 */ |