my_read.c
上传用户:romrleung
上传日期:2022-05-23
资源大小:18897k
文件大小:2k
- /* Copyright (C) 2000 MySQL AB
- 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; either version 2 of the License, or
- (at your option) any later version.
- 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
- #include "mysys_priv.h"
- #include "mysys_err.h"
- #include <errno.h>
- /*
- Read a chunk of bytes from a file with retry's if needed
- The parameters are:
- File descriptor
- Buffer to hold at least Count bytes
- Bytes to read
- Flags on what to do on error
- Return:
- -1 on error
- 0 if flag has bits MY_NABP or MY_FNABP set
- N number of bytes read.
- */
- uint my_read(File Filedes, byte *Buffer, uint Count, myf MyFlags)
- {
- uint readbytes,save_count;
- DBUG_ENTER("my_read");
- DBUG_PRINT("my",("Fd: %d Buffer: 0x%lx Count: %u MyFlags: %d",
- Filedes, Buffer, Count, MyFlags));
- save_count=Count;
- for (;;)
- {
- errno=0; /* Linux doesn't reset this */
- if ((readbytes = (uint) read(Filedes, Buffer, Count)) != Count)
- {
- my_errno=errno ? errno : -1;
- DBUG_PRINT("warning",("Read only %ld bytes off %ld from %d, errno: %d",
- readbytes,Count,Filedes,my_errno));
- #ifdef THREAD
- if (readbytes == 0 && errno == EINTR)
- continue; /* Interrupted */
- #endif
- if (MyFlags & (MY_WME | MY_FAE | MY_FNABP))
- {
- if ((int) readbytes == -1)
- my_error(EE_READ, MYF(ME_BELL+ME_WAITTANG),
- my_filename(Filedes),my_errno);
- else if (MyFlags & (MY_NABP | MY_FNABP))
- my_error(EE_EOFERR, MYF(ME_BELL+ME_WAITTANG),
- my_filename(Filedes),my_errno);
- }
- if ((int) readbytes == -1 ||
- ((MyFlags & (MY_FNABP | MY_NABP)) && !(MyFlags & MY_FULL_IO)))
- DBUG_RETURN(MY_FILE_ERROR); /* Return with error */
- if (readbytes > 0 && (MyFlags & MY_FULL_IO))
- {
- Buffer+=readbytes;
- Count-=readbytes;
- continue;
- }
- }
- if (MyFlags & (MY_NABP | MY_FNABP))
- readbytes=0; /* Ok on read */
- else if (MyFlags & MY_FULL_IO)
- readbytes=save_count;
- break;
- }
- DBUG_RETURN(readbytes);
- } /* my_read */