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SqMod/module/Vendor/MDBC/libmariadb/my_symlink.c
2020-03-22 14:54:40 +02:00

139 lines
3.3 KiB
C

/* 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., 51 Franklin Street, Fifth Floor, Boston,
MA 02111-1301, USA */
#include "mysys_priv.h"
#include "mysys_err.h"
#include <m_string.h>
#include <errno.h>
#ifdef HAVE_REALPATH
#include <sys/param.h>
#include <sys/stat.h>
#endif
/*
Reads the content of a symbolic link
If the file is not a symbolic link, return the original file name in to.
Returns: 0 if table was a symlink,
1 if table was a normal file
-1 on error.
*/
int my_readlink(char *to, const char *filename, myf MyFlags)
{
#ifndef HAVE_READLINK
strmov(to,filename);
return 1;
#else
int result=0;
int length;
DBUG_ENTER("my_readlink");
if ((length=readlink(filename, to, FN_REFLEN-1)) < 0)
{
/* Don't give an error if this wasn't a symlink */
if ((my_errno=errno) == EINVAL)
{
result= 1;
strmov(to,filename);
}
else
{
if (MyFlags & MY_WME)
my_error(EE_CANT_READLINK, MYF(0), filename, errno);
result= -1;
}
}
else
to[length]=0;
DBUG_RETURN(result);
#endif /* HAVE_READLINK */
}
/* Create a symbolic link */
int my_symlink(const char *content, const char *linkname, myf MyFlags)
{
#ifndef HAVE_READLINK
return 0;
#else
int result;
DBUG_ENTER("my_symlink");
result= 0;
if (symlink(content, linkname))
{
result= -1;
my_errno=errno;
if (MyFlags & MY_WME)
my_error(EE_CANT_SYMLINK, MYF(0), linkname, content, errno);
}
DBUG_RETURN(result);
#endif /* HAVE_READLINK */
}
/*
Resolve all symbolic links in path
'to' may be equal to 'filename'
Because purify gives a lot of UMR errors when using realpath(),
this code is disabled when using purify.
If MY_RESOLVE_LINK is given, only do realpath if the file is a link.
*/
#if defined(SCO)
#define BUFF_LEN 4097
#elif defined(MAXPATHLEN)
#define BUFF_LEN MAXPATHLEN
#else
#define BUFF_LEN FN_LEN
#endif
int my_realpath(char *to, const char *filename, myf MyFlags)
{
#if defined(HAVE_REALPATH) && !defined(HAVE_purify) && !defined(HAVE_BROKEN_REALPATH)
int result=0;
char buff[BUFF_LEN];
struct stat stat_buff;
DBUG_ENTER("my_realpath");
if (!(MyFlags & MY_RESOLVE_LINK) ||
(!lstat(filename,&stat_buff) && S_ISLNK(stat_buff.st_mode)))
{
char *ptr;
if ((ptr=realpath(filename,buff)))
strmake(to,ptr,FN_REFLEN-1);
else
{
/* Realpath didn't work; Use original name */
my_errno=errno;
if (MyFlags & MY_WME)
my_error(EE_REALPATH, MYF(0), filename, my_errno);
if (to != filename)
strmov(to,filename);
result= -1;
}
}
DBUG_RETURN(result);
#else
if (to != filename)
strmov(to,filename);
return 0;
#endif
}