rm_/lib/mkfifoat.c

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2022-07-28 14:16:50 +08:00
/* Create a named fifo relative to an open directory.
Copyright (C) 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 Eric Blake */
#include <config.h>
/* Specification. */
#include <sys/stat.h>
#include <stdlib.h>
#if HAVE_MKFIFOAT
# include <errno.h>
# include <fcntl.h>
# include <string.h>
int
rpl_mkfifoat (int fd, char const *file, mode_t mode)
#undef mkfifoat
{
/* Use the original mkfifoat(), but correct the trailing slash handling. */
size_t len = strlen (file);
if (len && file[len - 1] == '/')
{
struct stat st;
if (fstatat (fd, file, &st, AT_SYMLINK_NOFOLLOW) < 0)
{
if (errno == EOVERFLOW)
/* It's surely a file, not a directory. */
errno = ENOTDIR;
}
else
{
/* It's a directory, otherwise fstatat() would have reported an error
ENOTDIR. */
errno = EEXIST;
}
return -1;
}
return mkfifoat (fd, file, mode);
}
#else
# if !HAVE_MKFIFO
# include <errno.h>
/* Mingw lacks mkfifo, so this wrapper is trivial. */
int
mkfifoat (_GL_UNUSED int fd, _GL_UNUSED char const *path,
_GL_UNUSED mode_t mode)
{
errno = ENOSYS;
return -1;
}
# else /* HAVE_MKFIFO */
/* Create a named fifo FILE relative to directory FD, with access
permissions in MODE. If possible, do it without changing the
working directory. Otherwise, resort to using save_cwd/fchdir,
then mkfifo/restore_cwd. If either the save_cwd or the restore_cwd
fails, then give a diagnostic and exit nonzero. */
# define AT_FUNC_NAME mkfifoat
# define AT_FUNC_F1 mkfifo
# define AT_FUNC_POST_FILE_PARAM_DECLS , mode_t mode
# define AT_FUNC_POST_FILE_ARGS , mode
# include "at-func.c"
# undef AT_FUNC_NAME
# undef AT_FUNC_F1
# undef AT_FUNC_POST_FILE_PARAM_DECLS
# undef AT_FUNC_POST_FILE_ARGS
# endif /* HAVE_MKFIFO */
#endif /* HAVE_MKFIFOAT */