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252b5132 RH |
1 | /* Compare two open file descriptors to see if they refer to the same file. |
2 | Copyright (C) 1991 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., 59 Temple Place - Suite 330, | |
18 | Boston, MA 02111-1307, USA. */ | |
19 | ||
20 | ||
21 | /* | |
22 | ||
23 | NAME | |
24 | ||
25 | fdmatch -- see if two file descriptors refer to same file | |
26 | ||
27 | SYNOPSIS | |
28 | ||
29 | int fdmatch (int fd1, int fd2) | |
30 | ||
31 | DESCRIPTION | |
32 | ||
33 | Check to see if two open file descriptors refer to the same file. | |
34 | This is useful, for example, when we have an open file descriptor | |
35 | for an unnamed file, and the name of a file that we believe to | |
36 | correspond to that fd. This can happen when we are exec'd with | |
37 | an already open file (stdout for example) or from the SVR4 /proc | |
38 | calls that return open file descriptors for mapped address spaces. | |
39 | All we have to do is open the file by name and check the two file | |
40 | descriptors for a match, which is done by comparing major&minor | |
41 | device numbers and inode numbers. | |
42 | ||
43 | BUGS | |
44 | ||
45 | (FIXME: does this work for networks?) | |
46 | It works for NFS, which assigns a device number to each mount. | |
47 | ||
48 | */ | |
49 | ||
50 | #include "ansidecl.h" | |
51 | #include "libiberty.h" | |
52 | #include <sys/types.h> | |
53 | #include <sys/stat.h> | |
54 | ||
55 | int fdmatch (fd1, fd2) | |
56 | int fd1; | |
57 | int fd2; | |
58 | { | |
59 | struct stat sbuf1; | |
60 | struct stat sbuf2; | |
61 | ||
62 | if ((fstat (fd1, &sbuf1) == 0) && | |
63 | (fstat (fd2, &sbuf2) == 0) && | |
64 | (sbuf1.st_dev == sbuf2.st_dev) && | |
65 | (sbuf1.st_ino == sbuf2.st_ino)) | |
66 | { | |
67 | return (1); | |
68 | } | |
69 | else | |
70 | { | |
71 | return (0); | |
72 | } | |
73 | } |