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/* open for MMIXware.
Copyright (C) 2001, 2002 Hans-Peter Nilsson
Permission to use, copy, modify, and distribute this software is
freely granted, provided that the above copyright notice, this notice
and the following disclaimer are preserved with no changes.
THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE. */
#include <stdlib.h>
#include <fcntl.h>
#include <_ansi.h>
#include <sys/types.h>
#include <sys/stat.h>
#include "sys/syscall.h"
#include <errno.h>
/* Let's keep the filehandle array here, since this is a primary
initializer of it. */
unsigned char _MMIX_allocated_filehandle[32] =
{
1,
1,
1,
0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0
};
int
_open (const char *path,
int flags, ...)
{
long fileno;
unsigned char mode;
long append_contents = 0;
unsigned long prev_contents_size = 0;
char *prev_contents = NULL;
long ret;
for (fileno = 0;
fileno < (sizeof (_MMIX_allocated_filehandle) /
sizeof (_MMIX_allocated_filehandle[0]));
fileno++)
if (_MMIX_allocated_filehandle[fileno] == 0)
break;
if (fileno == (sizeof (_MMIX_allocated_filehandle) /
sizeof (_MMIX_allocated_filehandle[0])))
{
errno = EMFILE;
return -1;
}
/* We map this to a fopen call. The flags parameter is stymied because
we don't support other than these flags. */
if (flags & ~(O_RDONLY | O_WRONLY | O_RDWR | O_CREAT | O_APPEND | O_TRUNC))
{
UNIMPLEMENTED (("path: %s, flags: %d", path, flags));
errno = ENOSYS;
return -1;
}
if ((flags & O_ACCMODE) == O_RDONLY)
mode = BinaryRead;
else if ((flags & (O_WRONLY | O_APPEND)) == (O_WRONLY | O_APPEND))
{
mode = BinaryReadWrite;
append_contents = 1;
}
else if ((flags & (O_RDWR | O_APPEND)) == (O_RDWR | O_APPEND))
{
mode = BinaryReadWrite;
append_contents = 1;
}
else if ((flags & (O_WRONLY | O_CREAT)) == (O_WRONLY | O_CREAT)
|| (flags & (O_WRONLY | O_TRUNC)) == (O_WRONLY | O_TRUNC))
mode = BinaryWrite;
else if ((flags & (O_RDWR | O_CREAT)) == (O_RDWR | O_CREAT))
mode = BinaryReadWrite;
else if (flags & O_RDWR)
mode = BinaryReadWrite;
else
{
errno = EINVAL;
return -1;
}
if (append_contents)
{
/* BinaryReadWrite is equal to "w+", so it truncates the file rather
than keeping the contents, as can be imagined if you're looking
for append functionality. The only way we can keep the contents
so we can append to it, is by first reading in and saving the
contents, then re-opening the file as BinaryReadWrite and write
the previous contents. This seems to work for the needs of
simple test-programs. */
long openexist = TRAP3f (SYS_Fopen, fileno, path, BinaryRead);
if (openexist == 0)
{
/* Yes, this file exists, now opened, so let's read it and keep
the contents. Better have the memory around for this to
work. */
long seekval = TRAP2f (SYS_Fseek, fileno, -1);
if (seekval == 0)
{
prev_contents_size = TRAP1f (SYS_Ftell, fileno);
/* If the file has non-zero size, we have something to
append to. */
if (prev_contents_size != 0)
{
/* Start reading from the beginning. Ignore the return
value from this call: we'll notice if we can't read
as much as we want. */
TRAP2f (SYS_Fseek, fileno, 0);
prev_contents = malloc (prev_contents_size);
if (prev_contents != 0)
{
/* I don't like the thought of trying to read the
whole file all at once, disregarding the size,
because the host system might not support that
and we'd get funky errors. Read in 32k at a
time. */
char *ptr = prev_contents;
unsigned long read_more = prev_contents_size;
unsigned long chunk_size = 1 << 15;
while (read_more >= chunk_size)
{
long readval
= TRAP3f (SYS_Fread, fileno, ptr, chunk_size);
if (readval != 0)
{
free (prev_contents);
TRAP1f (SYS_Fclose, fileno);
errno = EIO;
return -1;
}
read_more -= chunk_size;
ptr += chunk_size;
}
if (read_more != 0)
{
long readval
= TRAP3f (SYS_Fread, fileno, ptr, read_more);
if (readval != 0)
{
free (prev_contents);
TRAP1f (SYS_Fclose, fileno);
errno = EIO;
return -1;
}
}
}
else
{
/* Malloc of area to copy to failed. The glibc
manpage says its open can return ENOMEM due to
kernel memory failures, so let's do that too
here. */
errno = ENOMEM;
return -1;
}
}
}
else
{
/* Seek failed. Gotta be some I/O error. */
errno = EIO;
return -1;
}
TRAP1f (SYS_Fclose, fileno);
}
}
ret = TRAP3f (SYS_Fopen, fileno, path, mode);
if (ret < 0)
{
/* It's totally unknown what the error was. We'll just take our
chances and assume ENOENT. */
errno = ENOENT;
return -1;
}
if (prev_contents_size != 0)
{
/* Write out the previous contents, a chunk at a time. Leave the
file pointer at the end of the file. */
unsigned long write_more = prev_contents_size;
unsigned long chunk_size = 1 << 15;
char *ptr = prev_contents;
while (write_more >= chunk_size)
{
long writeval
= TRAP3f (SYS_Fwrite, fileno, ptr, chunk_size);
if (writeval != 0)
{
free (prev_contents);
TRAP1f (SYS_Fclose, fileno);
errno = EIO;
return -1;
}
write_more -= chunk_size;
ptr += chunk_size;
}
if (write_more != 0)
{
long writeval
= TRAP3f (SYS_Fwrite, fileno, ptr, write_more);
if (writeval != 0)
{
free (prev_contents);
TRAP1f (SYS_Fclose, fileno);
errno = EIO;
return -1;
}
}
free (prev_contents);
}
_MMIX_allocated_filehandle[fileno] = 1;
return fileno;
}
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