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138 lines
3.9 KiB
C
138 lines
3.9 KiB
C
/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with this library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
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MA 02111-1307, USA */
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/*
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Advanced symlink handling.
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This is used in MyISAM to let users symlinks tables to different disk.
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The main idea with these functions is to automaticly create, delete and
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rename files and symlinks like they would be one unit.
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*/
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#include "mysys_priv.h"
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#include <m_string.h>
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File my_create_with_symlink(const char *linkname, const char *filename,
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int createflags, int access_flags, myf MyFlags)
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{
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File file;
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int tmp_errno;
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DBUG_ENTER("my_create_with_symlink");
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if ((file=my_create(filename, createflags, access_flags, MyFlags)) >= 0)
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{
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/* Test if we should create a link */
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if (linkname && strcmp(linkname,filename))
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{
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/* Delete old link/file */
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if (MyFlags & MY_DELETE_OLD)
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my_delete(linkname, MYF(0));
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/* Create link */
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if (my_symlink(filename, linkname, MyFlags))
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{
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/* Fail, remove everything we have done */
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tmp_errno=my_errno;
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my_close(file,MYF(0));
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my_delete(filename, MYF(0));
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file= -1;
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my_errno=tmp_errno;
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}
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}
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}
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DBUG_RETURN(file);
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}
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/*
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If the file was a symlink, delete both symlink and the file which the
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symlink pointed to.
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*/
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int my_delete_with_symlink(const char *name, myf MyFlags)
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{
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char link_name[FN_REFLEN];
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int was_symlink= (!my_disable_symlinks &&
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!my_readlink(link_name, name, MYF(0)));
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int result;
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DBUG_ENTER("my_delete_with_symlink");
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if (!(result=my_delete(name, MyFlags)))
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{
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if (was_symlink)
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result=my_delete(link_name, MyFlags);
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}
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DBUG_RETURN(result);
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}
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/*
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If the file is a normal file, just rename it.
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If the file is a symlink:
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- Create a new file with the name 'to' that points at
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symlink_dir/basename(to)
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- Rename the symlinked file to symlink_dir/basename(to)
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- Delete 'from'
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If something goes wrong, restore everything.
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*/
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int my_rename_with_symlink(const char *from, const char *to, myf MyFlags)
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{
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#ifndef HAVE_READLINK
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return my_rename(from, to, MyFlags);
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#else
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char link_name[FN_REFLEN], tmp_name[FN_REFLEN];
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int was_symlink= (!my_disable_symlinks &&
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!my_readlink(link_name, from, MYF(0)));
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int result=0;
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DBUG_ENTER("my_rename_with_symlink");
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if (!was_symlink)
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DBUG_RETURN(my_rename(from, to, MyFlags));
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/* Change filename that symlink pointed to */
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strmov(tmp_name, to);
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fn_same(tmp_name,link_name,1); /* Copy dir */
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/* Create new symlink */
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if (my_symlink(tmp_name, to, MyFlags))
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DBUG_RETURN(1);
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/*
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Rename symlinked file if the base name didn't change.
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This can happen if you use this function where 'from' and 'to' has
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the same basename and different directories.
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*/
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if (strcmp(link_name, tmp_name) && my_rename(link_name, tmp_name, MyFlags))
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{
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int save_errno=my_errno;
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my_delete(to, MyFlags); /* Remove created symlink */
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my_errno=save_errno;
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DBUG_RETURN(1);
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}
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/* Remove original symlink */
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if (my_delete(from, MyFlags))
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{
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int save_errno=my_errno;
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/* Remove created link */
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my_delete(to, MyFlags);
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/* Rename file back */
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if (strcmp(link_name, tmp_name))
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(void) my_rename(tmp_name, link_name, MyFlags);
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my_errno=save_errno;
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result= 1;
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}
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DBUG_RETURN(result);
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#endif /* HAVE_READLINK */
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}
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