diff options
Diffstat (limited to 'mysys/mf_tempfile.c')
| -rw-r--r-- | mysys/mf_tempfile.c | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/mysys/mf_tempfile.c b/mysys/mf_tempfile.c new file mode 100644 index 00000000..0f1c6d6b --- /dev/null +++ b/mysys/mf_tempfile.c @@ -0,0 +1,177 @@ +/* Copyright (c) 2000, 2013, 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 02110-1335 USA */ + +#include "mysys_priv.h" +#include <m_string.h> +#include "my_static.h" +#include "mysys_err.h" +#include <errno.h> +#ifdef HAVE_PATHS_H +#include <paths.h> +#endif + +#ifdef HAVE_MKOSTEMP +#define mkstemp(A) mkostemp(A, O_CLOEXEC) +#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. + + When passing MY_TEMPORARY flag in MyFlags the file is automatically deleted + + "mode" bits that always must be used for newly created files with + unique file names (O_EXCL | O_TRUNC | O_CREAT | O_RDWR) are added + automatically, and shouldn't be specified by the caller. + + 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, myf MyFlags) +{ + File file= -1; + + DBUG_ENTER("create_temp_file"); + DBUG_PRINT("enter", ("dir: %s, prefix: %s", dir ? dir : "(null)", prefix)); + DBUG_ASSERT((mode & (O_EXCL | O_TRUNC | O_CREAT | O_RDWR)) == 0); + + mode|= O_TRUNC | O_CREAT | O_RDWR; /* not O_EXCL, see Windows code below */ + +#ifdef _WIN32 + { + TCHAR path_buf[MAX_PATH-14]; + /* + 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) + DBUG_RETURN(-1); + + DBUG_PRINT("info", ("name: %s", to)); + + if (MyFlags & MY_TEMPORARY) + mode|= O_SHORT_LIVED | O_TEMPORARY; + + /* + Open the file without O_EXCL flag + since the file has already been created by GetTempFileName + */ + if ((file= my_open(to, mode, MyFlags)) < 0) + { + /* Open failed, remove the file created by GetTempFileName */ + int tmp= my_errno; + (void) my_delete(to, MYF(0)); + my_errno= tmp; + } + } +#elif defined(HAVE_MKSTEMP) + if (!dir && ! (dir =getenv("TMPDIR"))) + dir= DEFAULT_TMPDIR; +#ifdef O_TMPFILE + { + static int O_TMPFILE_works= 1; + + if ((MyFlags & MY_TEMPORARY) && O_TMPFILE_works) + { + /* explictly don't use O_EXCL here has it has a different + meaning with O_TMPFILE + */ + if ((file= open(dir, (mode & ~O_CREAT) | O_TMPFILE | O_CLOEXEC, + S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP)) >= 0) + { + my_snprintf(to, FN_REFLEN, "%s/#sql/fd=%d", dir, file); + file=my_register_filename(file, to, FILE_BY_O_TMPFILE, + EE_CANTCREATEFILE, MyFlags); + } + else if (errno == EOPNOTSUPP || errno == EINVAL) + { + my_printf_error(EE_CANTCREATEFILE, "O_TMPFILE is not supported on %s " + "(disabling future attempts)", + MYF(ME_NOTE | ME_ERROR_LOG_ONLY), dir); + O_TMPFILE_works= 0; + } + } + } + if (file == -1) +#endif /* O_TMPFILE */ + { + char prefix_buff[30]; + uint pfx_len; + File org_file; + + pfx_len= (uint) (strmov(strnmov(prefix_buff, + prefix ? prefix : "tmp.", + sizeof(prefix_buff)-7),"XXXXXX") - + prefix_buff); + if (strlen(dir)+ pfx_len > FN_REFLEN-2) + { + errno=my_errno= ENAMETOOLONG; + DBUG_RETURN(file); + } + strmov(convert_dirname(to,dir,NullS),prefix_buff); + org_file=mkstemp(to); + if (org_file >= 0 && (MyFlags & MY_TEMPORARY)) + (void) my_delete(to, MYF(MY_WME)); + 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)); + my_errno=tmp; + } + } +#else +#error No implementation found for create_temp_file +#endif + if (file >= 0) + statistic_increment(my_tmp_file_created,&THR_LOCK_open); + DBUG_RETURN(file); +} |