diff options
Diffstat (limited to 'mysys/my_symlink2.c')
| -rw-r--r-- | mysys/my_symlink2.c | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/mysys/my_symlink2.c b/mysys/my_symlink2.c new file mode 100644 index 00000000000..e77815df12a --- /dev/null +++ b/mysys/my_symlink2.c @@ -0,0 +1,155 @@ +/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public + License as published by the Free Software Foundation; either + version 2 of the License, or (at your option) any later version. + + This library 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 + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with this library; if not, write to the Free + Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, + MA 02111-1307, 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 automaticly 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=(linkname && strcmp(linkname,filename)); + DBUG_ENTER("my_create_with_symlink"); + + if (!(MyFlags & MY_DELETE_OLD)) + { + if (!access(filename,F_OK)) + { + my_error(EE_CANTCREATEFILE, MYF(0), filename, EEXIST); + DBUG_RETURN(-1); + } + if (create_link && !access(linkname,F_OK)) + { + 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 was a symlink, delete both symlink and the file which the + symlink pointed to. +*/ + +int my_delete_with_symlink(const char *name, myf MyFlags) +{ + char link_name[FN_REFLEN]; + int was_symlink= (!my_disable_symlinks && + !my_readlink(link_name, name, MYF(0))); + int result; + DBUG_ENTER("my_delete_with_symlink"); + + if (!(result=my_delete(name, MyFlags))) + { + if (was_symlink) + result=my_delete(link_name, MyFlags); + } + DBUG_RETURN(result); +} + +/* + 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; + 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 */ + + /* 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 (strcmp(link_name, tmp_name) && 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 */ +} |