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/* Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License, version 2.0,
as published by the Free Software Foundation.
This program is also distributed with certain software (including
but not limited to OpenSSL) that is licensed under separate terms,
as designated in a particular file or component or in included license
documentation. The authors of MySQL hereby grant you an additional
permission to link the program and your derivative works with the
separately licensed software that they have included with MySQL.
Without limiting anything contained in the foregoing, this file,
which is part of C Driver for MySQL (Connector/C), is also subject to the
Universal FOSS Exception, version 1.0, a copy of which can be found at
http://oss.oracle.com/licenses/universal-foss-exception.
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, version 2.0, 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 St, Fifth Floor, Boston, MA 02110-1301 USA */
/**
@file mysys/my_symlink2.cc
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 "my_config.h"
#include <errno.h>
#include <string.h>
#include "m_string.h"
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include "my_dbug.h"
#include "my_inttypes.h"
#include "my_io.h"
#include "my_sys.h"
#include "my_thread_local.h"
#include "mysys_err.h"
File my_create_with_symlink(const char *linkname, const char *filename,
int createflags, int access_flags, myf MyFlags) {
#ifdef _WIN32
if (linkname) filename = linkname;
if (!(MyFlags & MY_DELETE_OLD)) {
if (!access(filename, F_OK)) {
char errbuf[MYSYS_STRERROR_SIZE];
errno = EEXIST;
set_my_errno(EEXIST);
my_error(EE_CANTCREATEFILE, MYF(0), filename, EEXIST,
my_strerror(errbuf, sizeof(errbuf), EEXIST));
return -1;
}
}
return my_create(filename, createflags, access_flags, MyFlags);
#else
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_enable_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)) {
char errbuf[MYSYS_STRERROR_SIZE];
errno = EEXIST;
set_my_errno(EEXIST);
my_error(EE_CANTCREATEFILE, MYF(0), filename, EEXIST,
my_strerror(errbuf, sizeof(errbuf), EEXIST));
DBUG_RETURN(-1);
}
if (create_link && !access(linkname, F_OK)) {
char errbuf[MYSYS_STRERROR_SIZE];
errno = EEXIST;
set_my_errno(EEXIST);
my_error(EE_CANTCREATEFILE, MYF(0), linkname, EEXIST,
my_strerror(errbuf, sizeof(errbuf), 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;
set_my_errno(tmp_errno);
}
}
}
DBUG_RETURN(file);
#endif // !_WIN32
}
/*
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) {
#ifdef _WIN32
return my_delete(name, MyFlags);
#else
char link_name[FN_REFLEN];
int was_symlink =
(my_enable_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);
#endif // _WIN32
}
/*
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) {
#ifdef _WIN32
return my_rename(from, to, MyFlags);
#else
char link_name[FN_REFLEN], tmp_name[FN_REFLEN];
int was_symlink =
(my_enable_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 */
my_stpcpy(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)) {
set_my_errno(EEXIST);
if (MyFlags & MY_WME) {
char errbuf[MYSYS_STRERROR_SIZE];
my_error(EE_CANTCREATEFILE, MYF(0), tmp_name, EEXIST,
my_strerror(errbuf, sizeof(errbuf), 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 */
set_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);
set_my_errno(save_errno);
result = 1;
}
DBUG_RETURN(result);
#endif /* !_WIN32 */
}
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