size_t my_pread(File Filedes, uchar *Buffer, size_t Count, my_off_t offset,
myf MyFlags)
{
size_t readbytes;
int error= 0;
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(_WIN32)
readbytes= my_win_pread(Filedes, Buffer, Count, offset);
#else
readbytes= pread(Filedes, Buffer, Count, offset);
#endif
error= (readbytes != Count);
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));
if ((readbytes == 0 || readbytes == (size_t) -1) && errno == EINTR)
{
DBUG_PRINT("debug", ("my_pread() was interrupted and returned %d",
(int) readbytes));
continue; /* Interrupted */
}
if (MyFlags & (MY_WME | MY_FAE | MY_FNABP))
{
char errbuf[MYSYS_STRERROR_SIZE];
if (readbytes == (size_t) -1)
my_error(EE_READ, MYF(ME_BELL+ME_WAITTANG), my_filename(Filedes),
my_errno, my_strerror(errbuf, sizeof(errbuf), my_errno));
else if (MyFlags & (MY_NABP | MY_FNABP))
my_error(EE_EOFERR, MYF(ME_BELL+ME_WAITTANG), my_filename(Filedes),
my_errno, my_strerror(errbuf, sizeof(errbuf), 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 */
size_t my_pread(File Filedes, uchar *Buffer, size_t Count, my_off_t offset,
myf MyFlags)
{
size_t readbytes;
size_t total_readbytes= 0;
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 (readbytes > 0)
total_readbytes+= readbytes;
if(error)
{
if (readbytes > 0 && readbytes < Count && errno == 0)
{
/*
pread() may return less bytes than requested even if enough bytes are
available according to the Linux man page.
This makes determining the end-of-file condition a bit harder.
We just do another pread() call to see if more bytes can be read,
since all my_pread() users expect it to always return all available
bytes. For end-of-file 0 bytes is returned. This can never be the case
for a partial read, since according to the man page, -1 is returned
with errno set to EINTR if no data has been read.
*/
Buffer+= readbytes;
offset+= readbytes;
Count-= readbytes;
continue;
}
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));
if ((readbytes == 0 || readbytes == (size_t) -1) && errno == EINTR)
{
DBUG_PRINT("debug", ("my_pread() was interrupted and returned %d",
(int) readbytes));
continue; /* Interrupted */
}
if (MyFlags & (MY_WME | MY_FAE | MY_FNABP))
{
char errbuf[MYSYS_STRERROR_SIZE];
if (readbytes == (size_t) -1)
my_error(EE_READ, MYF(ME_BELL+ME_WAITTANG), my_filename(Filedes),
my_errno, my_strerror(errbuf, sizeof(errbuf), my_errno));
else if (MyFlags & (MY_NABP | MY_FNABP))
my_error(EE_EOFERR, MYF(ME_BELL+ME_WAITTANG), my_filename(Filedes),
my_errno, my_strerror(errbuf, sizeof(errbuf), 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(total_readbytes); /* purecov: inspected */
}
} /* my_pread */
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 */
