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199 lines
6.4 KiB
199 lines
6.4 KiB
/* Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License, version 2.0,
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as published by the Free Software Foundation.
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This program is also distributed with certain software (including
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but not limited to OpenSSL) that is licensed under separate terms,
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as designated in a particular file or component or in included license
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documentation. The authors of MySQL hereby grant you an additional
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permission to link the program and your derivative works with the
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separately licensed software that they have included with MySQL.
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Without limiting anything contained in the foregoing, this file,
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which is part of C Driver for MySQL (Connector/C), is also subject to the
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Universal FOSS Exception, version 1.0, a copy of which can be found at
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http://oss.oracle.com/licenses/universal-foss-exception.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License, version 2.0, for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
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/**
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@file mysys/mf_tempfile.cc
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*/
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#include "my_config.h"
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#include <errno.h>
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#ifdef HAVE_O_TMPFILE
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#include <fcntl.h>
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#endif
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#include <stdlib.h>
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#include <string.h>
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#include <sys/types.h>
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#include "m_string.h"
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#include "my_compiler.h"
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#include "my_dbug.h"
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#include "my_inttypes.h"
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#include "my_io.h"
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#include "my_sys.h"
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#include "my_thread_local.h"
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#include "mysql/psi/mysql_mutex.h"
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#include "mysys/mysys_priv.h"
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#include "mysys_err.h"
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#ifdef WIN32
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#include <fcntl.h> // O_EXCL
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#endif
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/*
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@brief
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Create a temporary file with unique name in a given directory
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@details
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create_temp_file
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to pointer to buffer where temporary filename will be stored
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dir directory where to create the file
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prefix prefix the filename with this
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mode Flags to use for my_create/my_open
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MyFlags Magic flags
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@return
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File descriptor of opened file if success
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-1 and sets errno if fails.
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@note
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The behaviour of this function differs a lot between
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implementation, it's main use is to generate a file with
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a name that does not already exist.
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The implementation using mkstemp should be considered the
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reference implementation when adding a new or modifying an
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existing one
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*/
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File create_temp_file(char *to, const char *dir, const char *prefix,
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int mode MY_ATTRIBUTE((unused)),
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UnlinkOrKeepFile unlink_or_keep, myf MyFlags) {
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File file = -1;
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#ifdef _WIN32
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TCHAR path_buf[MAX_PATH - 14];
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#endif
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DBUG_TRACE;
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DBUG_PRINT("enter", ("dir: %s, prefix: %s", dir, prefix));
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#if defined(_WIN32)
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/*
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Use GetTempPath to determine path for temporary files.
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This is because the documentation for GetTempFileName
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has the following to say about this parameter:
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"If this parameter is NULL, the function fails."
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*/
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if (!dir) {
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if (GetTempPath(sizeof(path_buf), path_buf) > 0) dir = path_buf;
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}
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/*
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Use GetTempFileName to generate a unique filename, create
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the file and release it's handle
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- uses up to the first three letters from prefix
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*/
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if (GetTempFileName(dir, prefix, 0, to) == 0) return -1;
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DBUG_PRINT("info", ("name: %s", to));
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/*
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Open the file without the "open only if file doesn't already exist"
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since the file has already been created by GetTempFileName
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*/
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if ((file = my_open(to, (mode & ~O_EXCL), MyFlags)) < 0) {
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/* Open failed, remove the file created by GetTempFileName */
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int tmp = my_errno();
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(void)my_delete(to, MYF(0));
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set_my_errno(tmp);
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return file;
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}
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if (unlink_or_keep == UNLINK_FILE) {
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my_delete(to, MYF(0));
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}
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#else /* mkstemp() is available on all non-Windows supported platforms. */
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#ifdef HAVE_O_TMPFILE
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if (unlink_or_keep == UNLINK_FILE) {
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if (!dir && !(dir = getenv("TMPDIR"))) dir = DEFAULT_TMPDIR;
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char dirname_buf[FN_REFLEN];
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convert_dirname(dirname_buf, dir, nullptr);
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// Verify that the generated filename will fit in a FN_REFLEN size buffer.
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int max_filename_len = snprintf(to, FN_REFLEN, "%s%.20sfd=%d", dirname_buf,
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prefix ? prefix : "tmp.", 4 * 1024 * 1024);
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if (max_filename_len >= FN_REFLEN) {
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errno = ENAMETOOLONG;
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set_my_errno(ENAMETOOLONG);
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return file;
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}
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/* Explicitly don't use O_EXCL here as it has a different
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meaning with O_TMPFILE.
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*/
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file = open(dirname_buf, O_RDWR | O_TMPFILE | O_CLOEXEC, S_IRUSR | S_IWUSR);
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if (file >= 0) {
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sprintf(to, "%s%.20sfd=%d", dirname_buf, prefix ? prefix : "tmp.", file);
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file = my_register_filename(file, to, FILE_BY_O_TMPFILE,
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EE_CANTCREATEFILE, MyFlags);
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}
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}
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// Fall through, in case open() failed above (or we have KEEP_FILE).
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#endif /* HAVE_O_TMPFILE */
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if (file == -1) {
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char prefix_buff[30];
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uint pfx_len;
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File org_file;
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pfx_len = (uint)(my_stpcpy(my_stpnmov(prefix_buff, prefix ? prefix : "tmp.",
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sizeof(prefix_buff) - 7),
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"XXXXXX") -
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prefix_buff);
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if (!dir && !(dir = getenv("TMPDIR"))) dir = DEFAULT_TMPDIR;
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if (strlen(dir) + pfx_len > FN_REFLEN - 2) {
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errno = ENAMETOOLONG;
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set_my_errno(ENAMETOOLONG);
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return file;
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}
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my_stpcpy(convert_dirname(to, dir, NullS), prefix_buff);
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org_file = mkstemp(to);
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file = my_register_filename(org_file, to, FILE_BY_MKSTEMP,
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EE_CANTCREATEFILE, MyFlags);
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/* If we didn't manage to register the name, remove the temp file */
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if (org_file >= 0 && file < 0) {
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int tmp = my_errno();
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close(org_file);
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(void)my_delete(to, MYF(MY_WME));
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set_my_errno(tmp);
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return file;
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}
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if (unlink_or_keep == UNLINK_FILE) {
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unlink(to);
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}
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}
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#endif
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if (file >= 0) {
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mysql_mutex_lock(&THR_LOCK_open);
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my_tmp_file_created++;
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mysql_mutex_unlock(&THR_LOCK_open);
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}
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return file;
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}
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