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glibc  2.9
symlink.c
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00001 /* Copyright (C) 1991, 92, 93, 94, 95, 96, 97 Free Software Foundation, Inc.
00002    This file is part of the GNU C Library.
00003 
00004    The GNU C Library is free software; you can redistribute it and/or
00005    modify it under the terms of the GNU Lesser General Public
00006    License as published by the Free Software Foundation; either
00007    version 2.1 of the License, or (at your option) any later version.
00008 
00009    The GNU C Library is distributed in the hope that it will be useful,
00010    but WITHOUT ANY WARRANTY; without even the implied warranty of
00011    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00012    Lesser General Public License for more details.
00013 
00014    You should have received a copy of the GNU Lesser General Public
00015    License along with the GNU C Library; if not, write to the Free
00016    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00017    02111-1307 USA.  */
00018 
00019 #include <string.h>
00020 #include <unistd.h>
00021 #include <hurd.h>
00022 #include <hurd/paths.h>
00023 #include <fcntl.h>
00024 
00025 /* Make a link to FROM called TO.  */
00026 int
00027 __symlink (from, to)
00028      const char *from;
00029      const char *to;
00030 {
00031   error_t err;
00032   file_t dir, node;
00033   char *name;
00034   const size_t len = strlen (from) + 1;
00035   char buf[sizeof (_HURD_SYMLINK) + len];
00036 
00037   /* A symlink is a file whose translator is "/hurd/symlink\0target\0".  */
00038 
00039   memcpy (buf, _HURD_SYMLINK, sizeof (_HURD_SYMLINK));
00040   memcpy (&buf[sizeof (_HURD_SYMLINK)], from, len);
00041 
00042   dir = __file_name_split (to, &name);
00043   if (dir == MACH_PORT_NULL)
00044     return -1;
00045 
00046   /* Create a new, unlinked node in the target directory.  */
00047   err = __dir_mkfile (dir, O_WRITE, 0777 & ~_hurd_umask, &node);
00048 
00049   if (! err)
00050     /* Set the node's translator to make it a symlink.  */
00051     err = __file_set_translator (node,
00052                              FS_TRANS_EXCL|FS_TRANS_SET,
00053                              FS_TRANS_EXCL|FS_TRANS_SET, 0,
00054                              buf, sizeof (_HURD_SYMLINK) + len,
00055                              MACH_PORT_NULL, MACH_MSG_TYPE_COPY_SEND);
00056 
00057   if (! err)
00058     /* Link the node, now a valid symlink, into the target directory.  */
00059     err = __dir_link (dir, node, name, 1);
00060 
00061   __mach_port_deallocate (__mach_task_self (), dir);
00062   __mach_port_deallocate (__mach_task_self (), node);
00063 
00064   if (err)
00065     return __hurd_fail (err);
00066   return 0;
00067 }
00068 
00069 weak_alias (__symlink, symlink)