diff options
Diffstat (limited to 'mysys/my_read.c')
| -rw-r--r-- | mysys/my_read.c | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/mysys/my_read.c b/mysys/my_read.c new file mode 100644 index 00000000..6b4f17e9 --- /dev/null +++ b/mysys/my_read.c @@ -0,0 +1,112 @@ +/* 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 "mysys_err.h" +#include <my_base.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. +*/ + +size_t my_read(File Filedes, uchar *Buffer, size_t Count, myf MyFlags) +{ + size_t readbytes, save_count= 0; + DBUG_ENTER("my_read"); + DBUG_PRINT("my",("fd: %d Buffer: %p Count: %lu MyFlags: %lu", + Filedes, Buffer, (ulong) Count, MyFlags)); + if (!(MyFlags & (MY_WME | MY_FAE | MY_FNABP))) + MyFlags|= my_global_flags; + + for (;;) + { + errno= 0; /* Linux, Windows don't reset this on EOF/success */ +#ifdef _WIN32 + readbytes= my_win_read(Filedes, Buffer, Count); +#else + readbytes= read(Filedes, Buffer, Count); +#endif + DBUG_EXECUTE_IF ("simulate_file_read_error", + { + errno= ENOSPC; + readbytes= (size_t) -1; + DBUG_SET("-d,simulate_file_read_error"); + DBUG_SET("-d,simulate_my_b_fill_error"); + }); + + if (readbytes != Count) + { + int got_errno= my_errno= errno; + DBUG_PRINT("warning",("Read only %d bytes off %lu from %d, errno: %d", + (int) readbytes, (ulong) Count, Filedes, + got_errno)); + + if (got_errno == 0 || (readbytes != (size_t) -1 && + (MyFlags & (MY_NABP | MY_FNABP)))) + my_errno= HA_ERR_FILE_TOO_SHORT; + + if ((readbytes == 0 || (int) readbytes == -1) && got_errno == EINTR) + { + DBUG_PRINT("debug", ("my_read() was interrupted and returned %ld", + (long) readbytes)); + continue; /* Interrupted */ + } + + /* Do a read retry if we didn't get enough data on first read */ + if (readbytes != (size_t) -1 && readbytes != 0 && + (MyFlags & MY_FULL_IO)) + { + Buffer+= readbytes; + Count-= readbytes; + save_count+= readbytes; + continue; + } + + if (MyFlags & (MY_WME | MY_FAE | MY_FNABP)) + { + if (readbytes == (size_t) -1) + my_error(EE_READ, + MYF(ME_BELL | (MyFlags & (ME_NOTE | ME_ERROR_LOG))), + my_filename(Filedes), got_errno); + else if (MyFlags & (MY_NABP | MY_FNABP)) + my_error(EE_EOFERR, + MYF(ME_BELL | (MyFlags & (ME_NOTE | ME_ERROR_LOG))), + my_filename(Filedes), got_errno); + } + if (readbytes == (size_t) -1 || + ((MyFlags & (MY_FNABP | MY_NABP)) && !(MyFlags & MY_FULL_IO))) + DBUG_RETURN(MY_FILE_ERROR); /* Return with error */ + } + + if (MyFlags & (MY_NABP | MY_FNABP)) + readbytes= 0; /* Ok on read */ + else + readbytes+= save_count; + break; + } + DBUG_RETURN(readbytes); +} /* my_read */ |