diff options
Diffstat (limited to 'mysys/my_pread.c')
| -rw-r--r-- | mysys/my_pread.c | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/mysys/my_pread.c b/mysys/my_pread.c new file mode 100644 index 00000000000..1190f2cc81b --- /dev/null +++ b/mysys/my_pread.c @@ -0,0 +1,137 @@ +/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public + License as published by the Free Software Foundation; either + version 2 of the License, or (at your option) any later version. + + This library 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 + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with this library; 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> +#ifdef HAVE_PREAD +#include <unistd.h> +#endif + + /* Read a chunk of bytes from a file */ + +uint my_pread(File Filedes, byte *Buffer, uint Count, my_off_t offset, + myf MyFlags) +{ + uint readbytes; + DBUG_ENTER("my_pread"); + DBUG_PRINT("my",("Fd: %d Seek: %lu Buffer: %lx Count: %u MyFlags: %d", + Filedes, (ulong) offset, Buffer, Count, MyFlags)); + + for (;;) + { +#ifndef __WIN__ + errno=0; /* Linux doesn't reset this */ +#endif +#ifndef HAVE_PREAD + readbytes= (uint) -1; + if (lseek(Filedes, offset, MY_SEEK_SET) == -1L || + (readbytes = (uint) read(Filedes, Buffer, Count)) != Count) +#else + if ((readbytes = (uint) pread(Filedes, Buffer, Count, offset)) != Count) +#endif + { + my_errno=errno; + 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))) + DBUG_RETURN(MY_FILE_ERROR); /* Return with error */ + } + if (MyFlags & (MY_NABP | MY_FNABP)) + DBUG_RETURN(0); /* Ok vid l{sning */ + DBUG_RETURN(readbytes); /* purecov: inspected */ + } +} /* my_pread */ + + + /* Write a chunk of bytes to a file */ + +uint my_pwrite(int Filedes, const byte *Buffer, uint Count, my_off_t offset, + myf MyFlags) +{ + uint writenbytes,errors; + ulong written; + DBUG_ENTER("my_pwrite"); + DBUG_PRINT("my",("Fd: %d Seek: %lu Buffer: %lx Count: %d MyFlags: %d", + Filedes, (ulong) offset,Buffer, Count, MyFlags)); + errors=0; written=0L; + + for (;;) + { +#ifndef HAVE_PREAD + writenbytes= (uint) -1; + if (lseek(Filedes, offset, MY_SEEK_SET) != -1L && + (writenbytes = (uint) write(Filedes, Buffer, Count)) == Count) +#else + if ((writenbytes = (uint) pwrite(Filedes, Buffer, Count,offset)) == Count) +#endif + break; + if ((int) writenbytes != -1) + { /* Safegueard */ + written+=writenbytes; + Buffer+=writenbytes; + Count-=writenbytes; + offset+=writenbytes; + } + my_errno=errno; + DBUG_PRINT("error",("Write only %d bytes",writenbytes)); +#ifndef NO_BACKGROUND +#ifdef THREAD + if (my_thread_var->abort) + MyFlags&= ~ MY_WAIT_IF_FULL; /* End if aborted by user */ +#endif + if (my_errno == ENOSPC && (MyFlags & MY_WAIT_IF_FULL)) + { + if (!(errors++ % MY_WAIT_GIVE_USER_A_MESSAGE)) + my_error(EE_DISK_FULL,MYF(ME_BELL | ME_NOREFRESH), + my_filename(Filedes)); + VOID(sleep(MY_WAIT_FOR_USER_TO_FIX_PANIC)); + continue; + } + if ((writenbytes == 0 && my_errno == EINTR) || + (writenbytes > 0 && (uint) writenbytes != (uint) -1)) + continue; /* Retry */ +#endif + if (MyFlags & (MY_NABP | MY_FNABP)) + { + if (MyFlags & (MY_WME | MY_FAE | MY_FNABP)) + { + my_error(EE_WRITE, MYF(ME_BELL+ME_WAITTANG), + my_filename(Filedes),my_errno); + } + DBUG_RETURN(MY_FILE_ERROR); /* Error on read */ + } + else + break; /* Return bytes written */ + } + if (MyFlags & (MY_NABP | MY_FNABP)) + DBUG_RETURN(0); /* Want only errors */ + DBUG_RETURN(writenbytes+written); /* purecov: inspected */ +} /* my_write */ |