Return to fdmatch.c CVS log

Up to [Apple XNU] / GNUtools / libg++ / libiberty

Annotation of GNUtools/libg++/libiberty/fdmatch.c, revision 1.1.1.1

1.1       root        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., 675 Mass Ave,
                     18: Cambridge, MA 02139, 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 <sys/types.h>
                     51: #include <sys/stat.h>
                     52: 
                     53: int fdmatch (fd1, fd2)
                     54:        int fd1;
                     55:        int fd2;
                     56: {
                     57:   struct stat sbuf1;
                     58:   struct stat sbuf2;
                     59: 
                     60:   if ((fstat (fd1, &sbuf1) == 0) &&
                     61:       (fstat (fd2, &sbuf2) == 0) &&
                     62:       (sbuf1.st_dev == sbuf2.st_dev) &&
                     63:       (sbuf1.st_ino == sbuf2.st_ino))
                     64:     {
                     65:       return (1);
                     66:     }
                     67:   else
                     68:     {
                     69:       return (0);
                     70:     }
                     71: }

This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.