diff options
Diffstat (limited to 'mysql/mysys/my_symlink.c')
| -rw-r--r-- | mysql/mysys/my_symlink.c | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/mysql/mysys/my_symlink.c b/mysql/mysys/my_symlink.c new file mode 100644 index 0000000..4777928 --- /dev/null +++ b/mysql/mysys/my_symlink.c @@ -0,0 +1,208 @@ +/* Copyright (c) 2001, 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 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 St, Fifth Floor, Boston, MA 02110-1301 USA */ + +#include "mysys_priv.h" +#include "my_sys.h" +#include "mysys_err.h" +#include <m_string.h> +#include <errno.h> +#include "my_thread_local.h" +#include "my_dir.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. + + RETURN + 0 If filename was a symlink, (to will be set to value of symlink) + 1 If filename was a normal file (to will be set to filename) + -1 on error. +*/ + +int my_readlink(char *to, const char *filename, myf MyFlags) +{ +#ifndef HAVE_READLINK + my_stpcpy(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 */ + set_my_errno(errno); + if (my_errno() == EINVAL) + { + result= 1; + my_stpcpy(to,filename); + } + else + { + if (MyFlags & MY_WME) + { + char errbuf[MYSYS_STRERROR_SIZE]; + my_error(EE_CANT_READLINK, MYF(0), filename, + errno, my_strerror(errbuf, sizeof(errbuf), errno)); + } + result= -1; + } + } + else + to[length]=0; + DBUG_PRINT("exit" ,("result: %d", result)); + 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"); + DBUG_PRINT("enter",("content: %s linkname: %s", content, linkname)); + + result= 0; + if (symlink(content, linkname)) + { + result= -1; + set_my_errno(errno); + if (MyFlags & MY_WME) + { + char errbuf[MYSYS_STRERROR_SIZE]; + my_error(EE_CANT_SYMLINK, MYF(0), linkname, content, + errno, my_strerror(errbuf, sizeof(errbuf), errno)); + } + } + else if ((MyFlags & MY_SYNC_DIR) && my_sync_dir_by_file(linkname, MyFlags)) + result= -1; + DBUG_RETURN(result); +#endif /* HAVE_READLINK */ +} + +#if defined(MAXPATHLEN) +#define BUFF_LEN MAXPATHLEN +#else +#define BUFF_LEN FN_LEN +#endif + + +int my_is_symlink(const char *filename MY_ATTRIBUTE((unused)), + ST_FILE_ID *file_id) +{ +#if defined (HAVE_LSTAT) && defined (S_ISLNK) + struct stat stat_buff; + int result= !lstat(filename, &stat_buff) && S_ISLNK(stat_buff.st_mode); + if (file_id && !result) + { + file_id->st_dev= stat_buff.st_dev; + file_id->st_ino= stat_buff.st_ino; + } + return result; +#elif defined (_WIN32) + DWORD dwAttr = GetFileAttributes(filename); + return (dwAttr != INVALID_FILE_ATTRIBUTES) && + (dwAttr & FILE_ATTRIBUTE_REPARSE_POINT); +#else /* No symlinks */ + return 0; +#endif +} + +/* + Resolve all symbolic links in path + 'to' may be equal to 'filename' +*/ + +int my_realpath(char *to, const char *filename, myf MyFlags) +{ +#if defined(HAVE_REALPATH) + int result=0; + char buff[BUFF_LEN]; + char *ptr; + DBUG_ENTER("my_realpath"); + + DBUG_PRINT("info",("executing realpath")); + if ((ptr=realpath(filename,buff))) + strmake(to,ptr,FN_REFLEN-1); + else + { + /* + Realpath didn't work; Use my_load_path() which is a poor substitute + original name but will at least be able to resolve paths that starts + with '.'. + */ + DBUG_PRINT("error",("realpath failed with errno: %d", errno)); + set_my_errno(errno); + if (MyFlags & MY_WME) + { + char errbuf[MYSYS_STRERROR_SIZE]; + my_error(EE_REALPATH, MYF(0), filename, + my_errno(), my_strerror(errbuf, sizeof(errbuf), my_errno())); + } + my_load_path(to, filename, NullS); + result= -1; + } + DBUG_RETURN(result); +#elif defined(_WIN32) + int ret= GetFullPathName(filename,FN_REFLEN, to, NULL); + if (ret == 0 || ret > FN_REFLEN) + { + set_my_errno((ret > FN_REFLEN) ? ENAMETOOLONG : GetLastError()); + if (MyFlags & MY_WME) + { + char errbuf[MYSYS_STRERROR_SIZE]; + my_error(EE_REALPATH, MYF(0), filename, + my_errno(), my_strerror(errbuf, sizeof(errbuf), my_errno())); + } + /* + GetFullPathName didn't work : use my_load_path() which is a poor + substitute original name but will at least be able to resolve + paths that starts with '.'. + */ + my_load_path(to, filename, NullS); + return -1; + } +#else + my_load_path(to, filename, NullS); +#endif + return 0; +} + + +/** + Return non-zero if the file descriptor and a previously lstat-ed file + identified by file_id point to the same file +*/ +int my_is_same_file(File file, const ST_FILE_ID *file_id) +{ + MY_STAT stat_buf; + if (my_fstat(file, &stat_buf, MYF(0)) == -1) + { + set_my_errno(errno); + return 0; + } + return (stat_buf.st_dev == file_id->st_dev) + && (stat_buf.st_ino == file_id->st_ino); +} |