95 lines
2.8 KiB
C
95 lines
2.8 KiB
C
/* Check the access rights of a file relative to an open directory.
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Copyright (C) 2009-2020 Free Software Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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/* written by Eric Blake */
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/* If the user's config.h happens to include <unistd.h>, let it include only
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the system's <unistd.h> here, so that orig_faccessat doesn't recurse to
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rpl_faccessat. */
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#define _GL_INCLUDING_UNISTD_H
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#include <config.h>
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/* Specification. */
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#include <unistd.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/stat.h>
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#undef _GL_INCLUDING_UNISTD_H
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#if HAVE_FACCESSAT
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static int
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orig_faccessat (int fd, char const *name, int mode, int flag)
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{
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return faccessat (fd, name, mode, flag);
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}
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#endif
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/* Write "unistd.h" here, not <unistd.h>, otherwise OSF/1 5.1 DTK cc
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eliminates this include because of the preliminary #include <unistd.h>
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above. */
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#include "unistd.h"
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#ifndef HAVE_ACCESS
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/* Mingw lacks access, but it also lacks real vs. effective ids, so
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the gnulib euidaccess module is good enough. */
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# undef access
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# define access euidaccess
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#endif
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#if HAVE_FACCESSAT
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int
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rpl_faccessat (int fd, char const *file, int mode, int flag)
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{
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int result = orig_faccessat (fd, file, mode, flag);
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if (result == 0 && file[strlen (file) - 1] == '/')
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{
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struct stat st;
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result = fstatat (fd, file, &st, 0);
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if (result == 0 && !S_ISDIR (st.st_mode))
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{
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errno = ENOTDIR;
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return -1;
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}
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}
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return result;
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}
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#else /* !HAVE_FACCESSAT */
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/* Invoke access or euidaccess on file, FILE, using mode MODE, in the directory
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open on descriptor FD. If possible, do it without changing the
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working directory. Otherwise, resort to using save_cwd/fchdir, then
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(access|euidaccess)/restore_cwd. If either the save_cwd or the
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restore_cwd fails, then give a diagnostic and exit nonzero.
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Note that this implementation only supports AT_EACCESS, although some
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native versions also support AT_SYMLINK_NOFOLLOW. */
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# define AT_FUNC_NAME faccessat
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# define AT_FUNC_F1 euidaccess
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# define AT_FUNC_F2 access
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# define AT_FUNC_USE_F1_COND AT_EACCESS
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# define AT_FUNC_POST_FILE_PARAM_DECLS , int mode, int flag
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# define AT_FUNC_POST_FILE_ARGS , mode
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# include "at-func.c"
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#endif
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