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-rw-r--r--mysys/my_symlink2.c191
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diff --git a/mysys/my_symlink2.c b/mysys/my_symlink2.c
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+/* Copyright (c) 2000, 2001, 2003, 2005-2007 MySQL AB
+ Use is subject to license terms
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; version 2 of the License.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */
+
+/*
+ Advanced symlink handling.
+ This is used in MyISAM to let users symlinks tables to different disk.
+ The main idea with these functions is to automatically create, delete and
+ rename files and symlinks like they would be one unit.
+*/
+
+#include "mysys_priv.h"
+#include "mysys_err.h"
+#include <m_string.h>
+
+File my_create_with_symlink(const char *linkname, const char *filename,
+ int createflags, int access_flags, myf MyFlags)
+{
+ File file;
+ int tmp_errno;
+ /* Test if we should create a link */
+ int create_link;
+ char abs_linkname[FN_REFLEN];
+ DBUG_ENTER("my_create_with_symlink");
+ DBUG_PRINT("enter", ("linkname: %s filename: %s",
+ linkname ? linkname : "(NULL)",
+ filename ? filename : "(NULL)"));
+
+ if (my_disable_symlinks)
+ {
+ DBUG_PRINT("info", ("Symlinks disabled"));
+ /* Create only the file, not the link and file */
+ create_link= 0;
+ if (linkname)
+ filename= linkname;
+ }
+ else
+ {
+ if (linkname)
+ my_realpath(abs_linkname, linkname, MYF(0));
+ create_link= (linkname && strcmp(abs_linkname,filename));
+ }
+
+ if (!(MyFlags & MY_DELETE_OLD))
+ {
+ if (!access(filename,F_OK))
+ {
+ my_errno= errno= EEXIST;
+ my_error(EE_CANTCREATEFILE, MYF(0), filename, EEXIST);
+ DBUG_RETURN(-1);
+ }
+ if (create_link && !access(linkname,F_OK))
+ {
+ my_errno= errno= EEXIST;
+ my_error(EE_CANTCREATEFILE, MYF(0), linkname, EEXIST);
+ DBUG_RETURN(-1);
+ }
+ }
+
+ if ((file=my_create(filename, createflags, access_flags, MyFlags)) >= 0)
+ {
+ if (create_link)
+ {
+ /* Delete old link/file */
+ if (MyFlags & MY_DELETE_OLD)
+ my_delete(linkname, MYF(0));
+ /* Create link */
+ if (my_symlink(filename, linkname, MyFlags))
+ {
+ /* Fail, remove everything we have done */
+ tmp_errno=my_errno;
+ my_close(file,MYF(0));
+ my_delete(filename, MYF(0));
+ file= -1;
+ my_errno=tmp_errno;
+ }
+ }
+ }
+ DBUG_RETURN(file);
+}
+
+/*
+ If the file is a normal file, just rename it.
+ If the file is a symlink:
+ - Create a new file with the name 'to' that points at
+ symlink_dir/basename(to)
+ - Rename the symlinked file to symlink_dir/basename(to)
+ - Delete 'from'
+ If something goes wrong, restore everything.
+*/
+
+int my_rename_with_symlink(const char *from, const char *to, myf MyFlags)
+{
+#ifndef HAVE_READLINK
+ return my_rename(from, to, MyFlags);
+#else
+ char link_name[FN_REFLEN], tmp_name[FN_REFLEN];
+ int was_symlink= (!my_disable_symlinks &&
+ !my_readlink(link_name, from, MYF(0)));
+ int result=0;
+ int name_is_different;
+ DBUG_ENTER("my_rename_with_symlink");
+
+ if (!was_symlink)
+ DBUG_RETURN(my_rename(from, to, MyFlags));
+
+ /* Change filename that symlink pointed to */
+ strmov(tmp_name, to);
+ fn_same(tmp_name,link_name,1); /* Copy dir */
+ name_is_different= strcmp(link_name, tmp_name);
+ if (name_is_different && !access(tmp_name, F_OK))
+ {
+ my_errno= EEXIST;
+ if (MyFlags & MY_WME)
+ my_error(EE_CANTCREATEFILE, MYF(0), tmp_name, EEXIST);
+ DBUG_RETURN(1);
+ }
+
+ /* Create new symlink */
+ if (my_symlink(tmp_name, to, MyFlags))
+ DBUG_RETURN(1);
+
+ /*
+ Rename symlinked file if the base name didn't change.
+ This can happen if you use this function where 'from' and 'to' has
+ the same basename and different directories.
+ */
+
+ if (name_is_different && my_rename(link_name, tmp_name, MyFlags))
+ {
+ int save_errno=my_errno;
+ my_delete(to, MyFlags); /* Remove created symlink */
+ my_errno=save_errno;
+ DBUG_RETURN(1);
+ }
+
+ /* Remove original symlink */
+ if (my_delete(from, MyFlags))
+ {
+ int save_errno=my_errno;
+ /* Remove created link */
+ my_delete(to, MyFlags);
+ /* Rename file back */
+ if (strcmp(link_name, tmp_name))
+ (void) my_rename(tmp_name, link_name, MyFlags);
+ my_errno=save_errno;
+ result= 1;
+ }
+ DBUG_RETURN(result);
+#endif /* HAVE_READLINK */
+}
+
+/** delete a - possibly symlinked - table file
+
+ This is used to delete a file that is part of a table (e.g. MYI or MYD
+ file of MyISAM) when dropping a table. A file might be a symlink -
+ if the table was created with DATA DIRECTORY or INDEX DIRECTORY -
+ in this case both the symlink and the symlinked file are deleted,
+ but only if the symlinked file is not in the datadir.
+*/
+
+int my_handler_delete_with_symlink(const char *filename, myf sync_dir)
+{
+ char real[FN_REFLEN];
+ int res= 0;
+ DBUG_ENTER("my_handler_delete_with_symlink");
+
+ if (my_is_symlink(filename))
+ {
+ /*
+ Delete the symlinked file only if the symlink is not
+ pointing into datadir.
+ */
+ if (!(my_realpath(real, filename, MYF(0)) ||
+ mysys_test_invalid_symlink(real)))
+ res= my_delete(real, MYF(MY_NOSYMLINKS | sync_dir));
+ }
+ DBUG_RETURN(my_delete(filename, sync_dir) || res);
+}