/* Copyright (C) 2000 MySQL AB, 2008-2009 Sun Microsystems, Inc 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include "mysys_priv.h" #include "mysys_err.h" #include "my_base.h" #include #include #if defined (HAVE_PREAD) && !defined(_WIN32) #include #endif /* Read a chunk of bytes from a file from a given position SYNOPSIOS my_pread() Filedes File decsriptor Buffer Buffer to read data into Count Number of bytes to read offset Position to read from MyFlags Flags NOTES This differs from the normal pread() call in that we don't care to set the position in the file back to the original position if the system doesn't support pread(). RETURN (size_t) -1 Error # Number of bytes read */ size_t my_pread(File Filedes, uchar *Buffer, size_t Count, my_off_t offset, myf MyFlags) { size_t readbytes; int error= 0; #if !defined (HAVE_PREAD) && !defined (_WIN32) int save_errno; #endif DBUG_ENTER("my_pread"); DBUG_PRINT("my",("fd: %d Seek: %llu Buffer: %p Count: %lu MyFlags: %d", Filedes, (ulonglong)offset, Buffer, (ulong)Count, MyFlags)); for (;;) { errno= 0; /* Linux, Windows don't reset this on EOF/success */ #if !defined (HAVE_PREAD) && !defined (_WIN32) mysql_mutex_lock(&my_file_info[Filedes].mutex); readbytes= (uint) -1; error= (lseek(Filedes, offset, MY_SEEK_SET) == (my_off_t) -1 || (readbytes= read(Filedes, Buffer, Count)) != Count); save_errno= errno; mysql_mutex_unlock(&my_file_info[Filedes].mutex); if (error) errno= save_errno; #else #if defined(_WIN32) readbytes= my_win_pread(Filedes, Buffer, Count, offset); #else readbytes= pread(Filedes, Buffer, Count, offset); #endif error= (readbytes != Count); #endif if(error) { my_errno= errno ? errno : -1; if (errno == 0 || (readbytes != (size_t) -1 && (MyFlags & (MY_NABP | MY_FNABP)))) my_errno= HA_ERR_FILE_TOO_SHORT; DBUG_PRINT("warning",("Read only %d bytes off %u from %d, errno: %d", (int) readbytes, (uint) Count,Filedes,my_errno)); #ifdef THREAD if ((readbytes == 0 || readbytes == (size_t) -1) && errno == EINTR) { DBUG_PRINT("debug", ("my_pread() was interrupted and returned %d", (int) readbytes)); continue; /* Interrupted */ } #endif if (MyFlags & (MY_WME | MY_FAE | MY_FNABP)) { if (readbytes == (size_t) -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 (readbytes == (size_t) -1 || (MyFlags & (MY_FNABP | MY_NABP))) DBUG_RETURN(MY_FILE_ERROR); /* Return with error */ } if (MyFlags & (MY_NABP | MY_FNABP)) DBUG_RETURN(0); /* Read went ok; Return 0 */ DBUG_RETURN(readbytes); /* purecov: inspected */ } } /* my_pread */ /* Write a chunk of bytes to a file at a given position SYNOPSIOS my_pwrite() Filedes File decsriptor Buffer Buffer to write data from Count Number of bytes to write offset Position to write to MyFlags Flags NOTES This differs from the normal pwrite() call in that we don't care to set the position in the file back to the original position if the system doesn't support pwrite() RETURN (size_t) -1 Error # Number of bytes read */ size_t my_pwrite(File Filedes, const uchar *Buffer, size_t Count, my_off_t offset, myf MyFlags) { size_t writtenbytes, written; uint errors; DBUG_ENTER("my_pwrite"); DBUG_PRINT("my",("fd: %d Seek: %llu Buffer: %p Count: %lu MyFlags: %d", Filedes, offset, Buffer, (ulong)Count, MyFlags)); errors= 0; written= 0; for (;;) { #if !defined (HAVE_PREAD) && !defined (_WIN32) int error; writtenbytes= (size_t) -1; mysql_mutex_lock(&my_file_info[Filedes].mutex); error= (lseek(Filedes, offset, MY_SEEK_SET) != (my_off_t) -1 && (writtenbytes= write(Filedes, Buffer, Count)) == Count); mysql_mutex_unlock(&my_file_info[Filedes].mutex); if (error) break; #elif defined (_WIN32) writtenbytes= my_win_pwrite(Filedes, Buffer, Count, offset); #else writtenbytes= pwrite(Filedes, Buffer, Count, offset); #endif if(writtenbytes == Count) break; my_errno= errno; if (writtenbytes != (size_t) -1) { written+= writtenbytes; Buffer+= writtenbytes; Count-= writtenbytes; offset+= writtenbytes; } DBUG_PRINT("error",("Write only %u bytes", (uint) writtenbytes)); #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 || my_errno == EDQUOT) && (MyFlags & MY_WAIT_IF_FULL)) { wait_for_free_space(my_filename(Filedes), errors); errors++; continue; } if ((writtenbytes && writtenbytes != (size_t) -1) || my_errno == EINTR) 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 */ } DBUG_EXECUTE_IF("check", my_seek(Filedes, -1, SEEK_SET, MYF(0));); if (MyFlags & (MY_NABP | MY_FNABP)) DBUG_RETURN(0); /* Want only errors */ DBUG_RETURN(writtenbytes+written); /* purecov: inspected */ } /* my_pwrite */