/* Copyright (c) 2000, 2019, 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/mf_tempfile.cc */ #include "my_config.h" #include #ifdef HAVE_O_TMPFILE #include #endif #include #include #include #ifdef HAVE_UNISTD_H #include #endif #include "m_string.h" #include "my_compiler.h" #include "my_dbug.h" #include "my_inttypes.h" #include "my_io.h" #include "my_sys.h" #include "my_thread_local.h" #include "mysql/psi/mysql_mutex.h" #include "mysys/mysys_priv.h" #include "mysys_err.h" #ifdef WIN32 #include // O_EXCL #endif /* @brief Create a temporary file with unique name in a given directory @details create_temp_file to pointer to buffer where temporary filename will be stored dir directory where to create the file prefix prefix the filename with this mode Flags to use for my_create/my_open MyFlags Magic flags @return File descriptor of opened file if success -1 and sets errno if fails. @note The behaviour of this function differs a lot between implementation, it's main use is to generate a file with a name that does not already exist. The implementation using mkstemp should be considered the reference implementation when adding a new or modifying an existing one */ File create_temp_file(char *to, const char *dir, const char *prefix, int mode MY_ATTRIBUTE((unused)), UnlinkOrKeepFile unlink_or_keep, myf MyFlags) { File file = -1; #ifdef _WIN32 TCHAR path_buf[MAX_PATH - 14]; #endif DBUG_TRACE; DBUG_PRINT("enter", ("dir: %s, prefix: %s", dir, prefix)); #if defined(_WIN32) /* Use GetTempPath to determine path for temporary files. This is because the documentation for GetTempFileName has the following to say about this parameter: "If this parameter is NULL, the function fails." */ if (!dir) { if (GetTempPath(sizeof(path_buf), path_buf) > 0) dir = path_buf; } /* Use GetTempFileName to generate a unique filename, create the file and release it's handle - uses up to the first three letters from prefix */ if (GetTempFileName(dir, prefix, 0, to) == 0) return -1; DBUG_PRINT("info", ("name: %s", to)); /* Open the file without the "open only if file doesn't already exist" since the file has already been created by GetTempFileName */ if ((file = my_open(to, (mode & ~O_EXCL), MyFlags)) < 0) { /* Open failed, remove the file created by GetTempFileName */ int tmp = my_errno(); (void)my_delete(to, MYF(0)); set_my_errno(tmp); return file; } if (unlink_or_keep == UNLINK_FILE) { my_delete(to, MYF(0)); } #else /* mkstemp() is available on all non-Windows supported platforms. */ #ifdef HAVE_O_TMPFILE if (unlink_or_keep == UNLINK_FILE) { if (!dir && !(dir = getenv("TMPDIR"))) dir = DEFAULT_TMPDIR; char dirname_buf[FN_REFLEN]; convert_dirname(dirname_buf, dir, nullptr); // Verify that the generated filename will fit in a FN_REFLEN size buffer. int max_filename_len = snprintf(to, FN_REFLEN, "%s%.20sfd=%d", dirname_buf, prefix ? prefix : "tmp.", 4 * 1024 * 1024); if (max_filename_len >= FN_REFLEN) { errno = ENAMETOOLONG; set_my_errno(ENAMETOOLONG); return file; } /* Explicitly don't use O_EXCL here as it has a different meaning with O_TMPFILE. */ file = open(dirname_buf, O_RDWR | O_TMPFILE | O_CLOEXEC, S_IRUSR | S_IWUSR); if (file >= 0) { sprintf(to, "%s%.20sfd=%d", dirname_buf, prefix ? prefix : "tmp.", file); file = my_register_filename(file, to, FILE_BY_O_TMPFILE, EE_CANTCREATEFILE, MyFlags); } } // Fall through, in case open() failed above (or we have KEEP_FILE). #endif /* HAVE_O_TMPFILE */ if (file == -1) { char prefix_buff[30]; uint pfx_len; File org_file; pfx_len = (uint)(my_stpcpy(my_stpnmov(prefix_buff, prefix ? prefix : "tmp.", sizeof(prefix_buff) - 7), "XXXXXX") - prefix_buff); if (!dir && !(dir = getenv("TMPDIR"))) dir = DEFAULT_TMPDIR; if (strlen(dir) + pfx_len > FN_REFLEN - 2) { errno = ENAMETOOLONG; set_my_errno(ENAMETOOLONG); return file; } my_stpcpy(convert_dirname(to, dir, NullS), prefix_buff); org_file = mkstemp(to); file = my_register_filename(org_file, to, FILE_BY_MKSTEMP, EE_CANTCREATEFILE, MyFlags); /* If we didn't manage to register the name, remove the temp file */ if (org_file >= 0 && file < 0) { int tmp = my_errno(); close(org_file); (void)my_delete(to, MYF(MY_WME)); set_my_errno(tmp); return file; } if (unlink_or_keep == UNLINK_FILE) { unlink(to); } } #endif if (file >= 0) { mysql_mutex_lock(&THR_LOCK_open); my_tmp_file_created++; mysql_mutex_unlock(&THR_LOCK_open); } return file; }