diff options
Diffstat (limited to 'REORG.TODO/sysdeps/posix/shm-directory.h')
| -rw-r--r-- | REORG.TODO/sysdeps/posix/shm-directory.h | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/posix/shm-directory.h b/REORG.TODO/sysdeps/posix/shm-directory.h new file mode 100644 index 0000000000..5c70e1a71e --- /dev/null +++ b/REORG.TODO/sysdeps/posix/shm-directory.h @@ -0,0 +1,66 @@ +/* Header for directory for shm/sem files. + Copyright (C) 2014-2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#ifndef _SHM_DIRECTORY_H + +#include <errno.h> +#include <limits.h> +#include <stdbool.h> +#include <stdlib.h> +#include <string.h> + +extern const char *__shm_directory (size_t *len); + +/* This defines local variables SHM_DIR and SHM_DIRLEN, giving the + directory prefix (with trailing slash) and length (not including '\0' + terminator) of the directory used for shm files. If that cannot be + determined, it sets errno to ENOSYS and returns RETVAL_FOR_INVALID. + + This uses the local variable NAME as an lvalue, and increments it past + any leading slashes. It then defines the local variable NAMELEN, giving + strlen (NAME) + 1. If NAME is invalid, it sets errno to + ERRNO_FOR_INVALID and returns RETVAL_FOR_INVALID. Finally, it defines + the local variable SHM_NAME, giving the absolute file name of the shm + file corresponding to NAME. PREFIX is a string constant used as a + prefix on NAME. */ + +#define SHM_GET_NAME(errno_for_invalid, retval_for_invalid, prefix) \ + size_t shm_dirlen; \ + const char *shm_dir = __shm_directory (&shm_dirlen); \ + /* If we don't know what directory to use, there is nothing we can do. */ \ + if (__glibc_unlikely (shm_dir == NULL)) \ + { \ + __set_errno (ENOSYS); \ + return retval_for_invalid; \ + } \ + /* Construct the filename. */ \ + while (name[0] == '/') \ + ++name; \ + size_t namelen = strlen (name) + 1; \ + /* Validate the filename. */ \ + if (namelen == 1 || namelen >= NAME_MAX || strchr (name, '/') != NULL) \ + { \ + __set_errno (errno_for_invalid); \ + return retval_for_invalid; \ + } \ + char *shm_name = __alloca (shm_dirlen + sizeof prefix - 1 + namelen); \ + __mempcpy (__mempcpy (__mempcpy (shm_name, shm_dir, shm_dirlen), \ + prefix, sizeof prefix - 1), \ + name, namelen) + +#endif /* shm-directory.h */ |