| 1 | /* Compare two open file descriptors to see if they refer to the same file. |
|---|
| 2 | Copyright (C) 1991-2024 Free Software Foundation, Inc. |
|---|
| 3 | |
|---|
| 4 | This file is part of the libiberty library. |
|---|
| 5 | Libiberty is free software; you can redistribute it and/or |
|---|
| 6 | modify it under the terms of the GNU Library General Public |
|---|
| 7 | License as published by the Free Software Foundation; either |
|---|
| 8 | version 2 of the License, or (at your option) any later version. |
|---|
| 9 | |
|---|
| 10 | Libiberty is distributed in the hope that it will be useful, |
|---|
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
|---|
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
|---|
| 13 | Library General Public License for more details. |
|---|
| 14 | |
|---|
| 15 | You should have received a copy of the GNU Library General Public |
|---|
| 16 | License along with libiberty; see the file COPYING.LIB. If |
|---|
| 17 | not, write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor, |
|---|
| 18 | Boston, MA 02110-1301, USA. */ |
|---|
| 19 | |
|---|
| 20 | |
|---|
| 21 | /* |
|---|
| 22 | |
|---|
| 23 | @deftypefn Extension int fdmatch (int @var{fd1}, int @var{fd2}) |
|---|
| 24 | |
|---|
| 25 | Check to see if two open file descriptors refer to the same file. |
|---|
| 26 | This is useful, for example, when we have an open file descriptor for |
|---|
| 27 | an unnamed file, and the name of a file that we believe to correspond |
|---|
| 28 | to that fd. This can happen when we are exec'd with an already open |
|---|
| 29 | file (@code{stdout} for example) or from the SVR4 @file{/proc} calls |
|---|
| 30 | that return open file descriptors for mapped address spaces. All we |
|---|
| 31 | have to do is open the file by name and check the two file descriptors |
|---|
| 32 | for a match, which is done by comparing major and minor device numbers |
|---|
| 33 | and inode numbers. |
|---|
| 34 | |
|---|
| 35 | @end deftypefn |
|---|
| 36 | |
|---|
| 37 | BUGS |
|---|
| 38 | |
|---|
| 39 | (FIXME: does this work for networks?) |
|---|
| 40 | It works for NFS, which assigns a device number to each mount. |
|---|
| 41 | |
|---|
| 42 | */ |
|---|
| 43 | |
|---|
| 44 | #ifdef HAVE_CONFIG_H |
|---|
| 45 | #include "config.h" |
|---|
| 46 | #endif |
|---|
| 47 | #include "ansidecl.h" |
|---|
| 48 | #include "libiberty.h" |
|---|
| 49 | #include <sys/types.h> |
|---|
| 50 | #include <sys/stat.h> |
|---|
| 51 | |
|---|
| 52 | int fdmatch (int fd1, int fd2) |
|---|
| 53 | { |
|---|
| 54 | struct stat sbuf1; |
|---|
| 55 | struct stat sbuf2; |
|---|
| 56 | |
|---|
| 57 | if ((fstat (fd: fd1, buf: &sbuf1) == 0) && |
|---|
| 58 | (fstat (fd: fd2, buf: &sbuf2) == 0) && |
|---|
| 59 | (sbuf1.st_dev == sbuf2.st_dev) && |
|---|
| 60 | (sbuf1.st_ino == sbuf2.st_ino)) |
|---|
| 61 | { |
|---|
| 62 | return (1); |
|---|
| 63 | } |
|---|
| 64 | else |
|---|
| 65 | { |
|---|
| 66 | return (0); |
|---|
| 67 | } |
|---|
| 68 | } |
|---|
| 69 | |
|---|
