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69 lines
2.1 KiB
C
69 lines
2.1 KiB
C
/* Compare two open file descriptors to see if they refer to the same file.
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Copyright (C) 1991-2024 Free Software Foundation, Inc.
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This file is part of the libiberty library.
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Libiberty is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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Libiberty 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 GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with libiberty; see the file COPYING.LIB. If
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not, write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
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Boston, MA 02110-1301, USA. */
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/*
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@deftypefn Extension int fdmatch (int @var{fd1}, int @var{fd2})
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Check to see if two open file descriptors refer to the same file.
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This is useful, for example, when we have an open file descriptor for
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an unnamed file, and the name of a file that we believe to correspond
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to that fd. This can happen when we are exec'd with an already open
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file (@code{stdout} for example) or from the SVR4 @file{/proc} calls
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that return open file descriptors for mapped address spaces. All we
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have to do is open the file by name and check the two file descriptors
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for a match, which is done by comparing major and minor device numbers
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and inode numbers.
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@end deftypefn
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BUGS
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(FIXME: does this work for networks?)
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It works for NFS, which assigns a device number to each mount.
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include "ansidecl.h"
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#include "libiberty.h"
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#include <sys/types.h>
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#include <sys/stat.h>
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int fdmatch (int fd1, int fd2)
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{
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struct stat sbuf1;
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struct stat sbuf2;
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if ((fstat (fd1, &sbuf1) == 0) &&
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(fstat (fd2, &sbuf2) == 0) &&
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(sbuf1.st_dev == sbuf2.st_dev) &&
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(sbuf1.st_ino == sbuf2.st_ino))
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{
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return (1);
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}
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else
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{
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return (0);
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}
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}
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