128 lines
3.8 KiB
C++
128 lines
3.8 KiB
C++
/* 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/my_chsize.cc
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*/
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#include "my_config.h"
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#include <errno.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 "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 "mysys_err.h"
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#ifdef _WIN32
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#include "mysys/mysys_priv.h"
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#endif
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/*
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Change size of file.
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SYNOPSIS
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my_chsize()
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fd File descriptor
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new_length New file size
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filler If we don't have truncate, fill up all bytes after
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new_length with this character
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MyFlags Flags
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DESCRIPTION
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my_chsize() truncates file if shorter else fill with the filler character.
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The function also changes the file pointer. Usually it points to the end
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of the file after execution.
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RETURN VALUE
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0 Ok
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1 Error
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*/
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int my_chsize(File fd, my_off_t newlength, int filler, myf MyFlags) {
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my_off_t oldsize;
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uchar buff[IO_SIZE];
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DBUG_TRACE;
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DBUG_PRINT("my", ("fd: %d length: %lu MyFlags: %d", fd, (ulong)newlength,
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MyFlags));
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if ((oldsize = my_seek(fd, 0L, MY_SEEK_END, MYF(MY_WME + MY_FAE))) ==
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newlength)
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return 0;
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DBUG_PRINT("info", ("old_size: %ld", (ulong)oldsize));
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if (oldsize > newlength) {
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#ifdef _WIN32
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if (my_win_chsize(fd, newlength)) {
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set_my_errno(errno);
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goto err;
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}
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return 0;
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#elif defined(HAVE_FTRUNCATE)
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if (ftruncate(fd, (off_t)newlength)) {
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set_my_errno(errno);
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goto err;
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}
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return 0;
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#else
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/*
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Fill space between requested length and true length with 'filler'
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We should never come here on any modern machine
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*/
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if (my_seek(fd, newlength, MY_SEEK_SET, MYF(MY_WME + MY_FAE)) ==
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MY_FILEPOS_ERROR) {
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goto err;
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}
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std::swap(newlength, oldsize);
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#endif
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}
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/* Full file with 'filler' until it's as big as requested */
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memset(buff, filler, IO_SIZE);
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while (newlength - oldsize > IO_SIZE) {
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if (my_write(fd, buff, IO_SIZE, MYF(MY_NABP))) goto err;
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oldsize += IO_SIZE;
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}
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if (my_write(fd, buff, (size_t)(newlength - oldsize), MYF(MY_NABP))) goto err;
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return 0;
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err:
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DBUG_PRINT("error", ("errno: %d", errno));
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if (MyFlags & MY_WME) {
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char errbuf[MYSYS_STRERROR_SIZE];
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my_error(EE_CANT_CHSIZE, MYF(0), my_errno(),
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my_strerror(errbuf, sizeof(errbuf), my_errno()));
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}
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return 1;
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} /* my_chsize */
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