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glibc  2.9
linkat.c
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00001 /* Make a link between file names relative to open directories.  Hurd version.
00002    Copyright (C) 2006 Free Software Foundation, Inc.
00003    This file is part of the GNU C Library.
00004 
00005    The GNU C Library is free software; you can redistribute it and/or
00006    modify it under the terms of the GNU Lesser General Public
00007    License as published by the Free Software Foundation; either
00008    version 2.1 of the License, or (at your option) any later version.
00009 
00010    The GNU C Library is distributed in the hope that it will be useful,
00011    but WITHOUT ANY WARRANTY; without even the implied warranty of
00012    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00013    Lesser General Public License for more details.
00014 
00015    You should have received a copy of the GNU Lesser General Public
00016    License along with the GNU C Library; if not, write to the Free
00017    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00018    02111-1307 USA.  */
00019 
00020 #include <errno.h>
00021 #include <fcntl.h>
00022 #include <stddef.h>
00023 #include <unistd.h>
00024 #include <hurd.h>
00025 #include <hurd/fd.h>
00026 
00027 
00028 /* Make a link to FROM relative to FROMFD called TO relative to TOFD.  */
00029 int
00030 linkat (fromfd, from, tofd, to, flags)
00031      int fromfd;
00032      const char *from;
00033      int tofd;
00034      const char *to;
00035      int flags;
00036 {
00037   error_t err;
00038   file_t oldfile, linknode, todir;
00039   char *toname;
00040 
00041   oldfile = __file_name_lookup_at (fromfd, flags, from, 0, 0);
00042   if (oldfile == MACH_PORT_NULL)
00043     return -1;
00044 
00045   /* The file_getlinknode RPC returns the port that should be passed to
00046      the receiving filesystem (the one containing TODIR) in dir_link.  */
00047 
00048   err = __file_getlinknode (oldfile, &linknode);
00049   __mach_port_deallocate (__mach_task_self (), oldfile);
00050   if (err)
00051     return __hurd_fail (err);
00052 
00053   todir = __file_name_split_at (tofd, to, &toname);
00054   if (todir != MACH_PORT_NULL)
00055     {
00056       err = __dir_link (todir, linknode, toname, 1);
00057       __mach_port_deallocate (__mach_task_self (), todir);
00058     }
00059   __mach_port_deallocate (__mach_task_self (), linknode);
00060   if (todir == MACH_PORT_NULL)
00061     return -1;
00062 
00063   if (err)
00064     return __hurd_fail (err);
00065   return 0;
00066 }