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authorupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
committerupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
commit554fd8c5195424bdbcabf5de30fdc183aba391bd (patch)
tree976dc5ab7fddf506dadce60ae936f43f58787092 /libiberty/fdmatch.c
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diff --git a/libiberty/fdmatch.c b/libiberty/fdmatch.c
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+/* Compare two open file descriptors to see if they refer to the same file.
+ Copyright (C) 1991 Free Software Foundation, Inc.
+
+This file is part of the libiberty library.
+Libiberty is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public
+License as published by the Free Software Foundation; either
+version 2 of the License, or (at your option) any later version.
+
+Libiberty 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
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with libiberty; see the file COPYING.LIB. If
+not, write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
+Boston, MA 02110-1301, USA. */
+
+
+/*
+
+@deftypefn Extension int fdmatch (int @var{fd1}, int @var{fd2})
+
+Check to see if two open file descriptors refer to the same file.
+This is useful, for example, when we have an open file descriptor for
+an unnamed file, and the name of a file that we believe to correspond
+to that fd. This can happen when we are exec'd with an already open
+file (@code{stdout} for example) or from the SVR4 @file{/proc} calls
+that return open file descriptors for mapped address spaces. All we
+have to do is open the file by name and check the two file descriptors
+for a match, which is done by comparing major and minor device numbers
+and inode numbers.
+
+@end deftypefn
+
+BUGS
+
+ (FIXME: does this work for networks?)
+ It works for NFS, which assigns a device number to each mount.
+
+*/
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+#include "ansidecl.h"
+#include "libiberty.h"
+#include <sys/types.h>
+#include <sys/stat.h>
+
+int fdmatch (int fd1, int fd2)
+{
+ struct stat sbuf1;
+ struct stat sbuf2;
+
+ if ((fstat (fd1, &sbuf1) == 0) &&
+ (fstat (fd2, &sbuf2) == 0) &&
+ (sbuf1.st_dev == sbuf2.st_dev) &&
+ (sbuf1.st_ino == sbuf2.st_ino))
+ {
+ return (1);
+ }
+ else
+ {
+ return (0);
+ }
+}