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140 lines
4.8 KiB
140 lines
4.8 KiB
3 months ago
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/* 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_read.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 <stddef.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_base.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 "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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#ifndef _WIN32
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// Mock away read() for unit testing.
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ssize_t (*mock_read)(int fd, void *buf, size_t count) = nullptr;
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#endif
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/**
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Read a chunk of bytes from a file with retry's if needed
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If flag MY_FULL_IO is set then keep reading until EOF is found.
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@param Filedes the context to reset
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@param[out] Buffer Buffer to hold at least Count bytes
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@param Count Bytes to read
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@param MyFlags Flags on what to do on error
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@return Operation status
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@retval -1 on error
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@retval 0 if flag has bits MY_NABP or MY_FNABP set
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@retval N number of bytes read
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*/
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size_t my_read(File Filedes, uchar *Buffer, size_t Count, myf MyFlags) {
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size_t readbytes, savedbytes;
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DBUG_TRACE;
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DBUG_PRINT("my", ("fd: %d Buffer: %p Count: %lu MyFlags: %d", Filedes,
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Buffer, (ulong)Count, MyFlags));
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savedbytes = 0;
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for (;;) {
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errno = 0; /* Linux, Windows don't reset this on EOF/success */
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#ifdef _WIN32
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readbytes = my_win_read(Filedes, Buffer, Count);
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#else
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if (mock_read)
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readbytes = mock_read(Filedes, Buffer, Count);
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else
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readbytes = read(Filedes, Buffer, Count);
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#endif
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DBUG_EXECUTE_IF("simulate_file_read_error", {
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errno = ENOSPC;
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readbytes = (size_t)-1;
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DBUG_SET("-d,simulate_file_read_error");
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DBUG_SET("-d,simulate_my_b_fill_error");
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});
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if (readbytes != Count) {
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set_my_errno(errno);
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if (errno == 0 ||
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(readbytes != (size_t)-1 && (MyFlags & (MY_NABP | MY_FNABP))))
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set_my_errno(HA_ERR_FILE_TOO_SHORT);
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DBUG_PRINT("warning",
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("Read only %d bytes off %lu from %d, errno: %d",
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(int)readbytes, (ulong)Count, Filedes, my_errno()));
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if ((readbytes == 0 || (int)readbytes == -1) && errno == EINTR) {
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DBUG_PRINT("debug", ("my_read() was interrupted and returned %ld",
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(long)readbytes));
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continue; /* Interrupted */
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}
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if (MyFlags & (MY_WME | MY_FAE | MY_FNABP)) {
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char errbuf[MYSYS_STRERROR_SIZE];
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if (readbytes == (size_t)-1)
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my_error(EE_READ, MYF(0), my_filename(Filedes), my_errno(),
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my_strerror(errbuf, sizeof(errbuf), my_errno()));
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else if (MyFlags & (MY_NABP | MY_FNABP))
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my_error(EE_EOFERR, MYF(0), my_filename(Filedes), my_errno(),
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my_strerror(errbuf, sizeof(errbuf), my_errno()));
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}
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if (readbytes == (size_t)-1 ||
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((MyFlags & (MY_FNABP | MY_NABP)) && !(MyFlags & MY_FULL_IO)))
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return MY_FILE_ERROR; /* Return with error */
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/* readbytes == 0 when EOF. No need to continue in case of EOF */
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if (readbytes != 0 && (MyFlags & MY_FULL_IO)) {
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Buffer += readbytes;
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Count -= readbytes;
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savedbytes += readbytes;
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continue;
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}
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}
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if (MyFlags & (MY_NABP | MY_FNABP))
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readbytes = 0; /* Ok on read */
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else if (MyFlags & MY_FULL_IO)
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readbytes += savedbytes;
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break;
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}
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return readbytes;
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} /* my_read */
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