Mail Archives: djgpp-workers/2001/03/13/14:00:07
Hi guys,
Below is the complete patch for filling the 'EOF gap'. I added write.c and
llseek.c to this patch in case there are problems I didn't catch. The only
changes were to add and revise some comments. I assume a blurb for wc204.txi
is appropriate since this solves a problem that keeps coming up on c.o.m.d.
Index: include/libc/fd_props.h
===================================================================
RCS file: /cvs/djgpp/djgpp/include/libc/fd_props.h,v
retrieving revision 1.1
diff -c -p -r1.1 fd_props.h
*** fd_props.h 2001/03/07 05:34:26 1.1
--- fd_props.h 2001/03/13 18:47:06
*************** extern "C" {
*** 15,20 ****
--- 15,24 ----
/* Delete file when the last descriptor referencing it is closed. */
#define FILE_DESC_TEMPORARY 0x01
+ /* Tell write and _write to test for file offset greater than EOF. If so,
+ they will fill the gap with zeroes. */
+ #define FILE_DESC_FILL_TEST 0x02
+
typedef struct fd_properties fd_properties;
struct fd_properties
*************** int __clear_fd_properties(int _fd);
*** 35,40 ****
--- 39,54 ----
static __inline__ int __has_fd_properties(int _fd)
{
return __fd_properties && __fd_properties[_fd];
+ }
+
+ static __inline__ void __set_fd_flags(int _fd, unsigned long _flags)
+ {
+ __fd_properties[_fd]->flags |= _flags;
+ }
+
+ static __inline__ void __clear_fd_flags(int _fd, unsigned long _flags)
+ {
+ __fd_properties[_fd]->flags &= ~_flags;
}
#endif /* !_POSIX_SOURCE */
Index: src/libc/posix/unistd/lseek.c
===================================================================
RCS file: /cvs/djgpp/djgpp/src/libc/posix/unistd/lseek.c,v
retrieving revision 1.2
diff -c -p -r1.2 lseek.c
*** lseek.c 1998/06/28 17:29:36 1.2
--- lseek.c 2001/03/13 18:47:55
***************
*** 1,3 ****
--- 1,4 ----
+ /* Copyright (C) 2001 DJ Delorie, see COPYING.DJ for details */
/* Copyright (C) 1998 DJ Delorie, see COPYING.DJ for details */
/* Copyright (C) 1995 DJ Delorie, see COPYING.DJ for details */
#include <libc/stubs.h>
***************
*** 7,12 ****
--- 8,14 ----
#include <dpmi.h>
#include <sys/fsext.h>
#include <libc/dosio.h>
+ #include <libc/fd_props.h>
off_t
lseek(int handle, off_t offset, int whence)
*************** lseek(int handle, off_t offset, int when
*** 31,35 ****
--- 33,48 ----
errno = __doserr_to_errno(r.x.ax);
return -1;
}
+
+ if (__has_fd_properties(handle))
+ {
+ /* Set the fill test flag when the file pointer may move past EOF.
+ Clear the fill test flag when the file pointer can't be past EOF. */
+ if (offset > 0)
+ __set_fd_flags(handle, FILE_DESC_FILL_TEST);
+ else if (whence == SEEK_SET || whence == SEEK_END)
+ __clear_fd_flags(handle, FILE_DESC_FILL_TEST);
+ }
+
return (r.x.dx << 16) + r.x.ax;
}
Index: src/libc/compat/unistd/llseek.c
===================================================================
RCS file: /cvs/djgpp/djgpp/src/libc/compat/unistd/llseek.c,v
retrieving revision 1.1
diff -c -p -r1.1 llseek.c
*** llseek.c 2000/06/19 18:00:56 1.1
--- llseek.c 2001/03/13 18:48:18
***************
*** 1,3 ****
--- 1,4 ----
+ /* Copyright (C) 2001 DJ Delorie, see COPYING.DJ for details */
/*
* File llseek.c.
*
***************
*** 14,21 ****
#include <errno.h>
#include <libc/dosio.h>
#include <sys/fsext.h>
-
offset_t
llseek( int handle, offset_t offset, int whence )
{
--- 15,22 ----
#include <errno.h>
#include <libc/dosio.h>
#include <sys/fsext.h>
+ #include <libc/fd_props.h>
offset_t
llseek( int handle, offset_t offset, int whence )
{
*************** llseek( int handle, offset_t offset, int
*** 41,46 ****
--- 42,57 ----
{
errno = __doserr_to_errno(r.x.ax);
return -1;
+ }
+
+ if (__has_fd_properties(handle))
+ {
+ /* Set the fill test flag when the file pointer may move past EOF.
+ Clear the fill test flag when the file pointer can't be past EOF. */
+ if (offset > 0)
+ __set_fd_flags(handle, FILE_DESC_FILL_TEST);
+ else if (whence == SEEK_SET || whence == SEEK_END)
+ __clear_fd_flags(handle, FILE_DESC_FILL_TEST);
}
return( ( ( (unsigned)r.x.dx ) << 16) + r.x.ax );
}
Index: src/libc/posix/unistd/write.c
===================================================================
RCS file: /cvs/djgpp/djgpp/src/libc/posix/unistd/write.c,v
retrieving revision 1.3
diff -c -p -r1.3 write.c
*** write.c 1997/08/31 17:49:14 1.3
--- write.c 2001/03/13 18:50:48
***************
*** 1,3 ****
--- 1,4 ----
+ /* Copyright (C) 2001 DJ Delorie, see COPYING.DJ for details */
/* Copyright (C) 1997 DJ Delorie, see COPYING.DJ for details */
/* Copyright (C) 1996 DJ Delorie, see COPYING.DJ for details */
/* Copyright (C) 1995 DJ Delorie, see COPYING.DJ for details */
***************
*** 12,23 ****
--- 13,27 ----
#include <sys/fsext.h>
#include <libc/dosio.h>
#include <libc/ttyprvt.h>
+ #include <libc/fd_props.h>
#define tblen _go32_info_block.size_of_transfer_buffer
int (*__libc_write_termios_hook)(int handle, const void *buffer, size_t
count,
ssize_t *rv) = NULL;
+ int _write_fill_seek_gap(int fd);
+
ssize_t
write(int handle, const void* buffer, size_t count)
{
*************** write(int handle, const void* buffer, si
*** 45,50 ****
--- 49,61 ----
func(__FSEXT_write, &rv, &handle)) /* ... call extension ... */
return rv; /* ... and exit if handled. */
+ if (__has_fd_properties(handle)
+ && (__fd_properties[handle]->flags & FILE_DESC_FILL_TEST))
+ {
+ if (_write_fill_seek_gap(handle) < 0)
+ return -1;
+ }
+
while (offset_into_buf < count)
{
_farsetsel(_dos_ds);
Index: src/libc/dos/io/_write.c
===================================================================
RCS file: /cvs/djgpp/djgpp/src/libc/dos/io/_write.c,v
retrieving revision 1.3
diff -c -p -r1.3 _write.c
*** _write.c 1996/10/24 23:26:26 1.3
--- _write.c 2001/03/13 18:50:55
***************
*** 10,16 ****
--- 10,20 ----
#include <sys/fsext.h>
#include <libc/dosio.h>
+ #include <libc/fd_props.h>
+ #include <libc/farptrgs.h>
+ int _write_fill_seek_gap(int fd);
+
int
_write(int handle, const void* buffer, size_t count)
{
*************** _write(int handle, const void* buffer, s
*** 27,32 ****
--- 31,43 ----
return rv;
}
+ if (__has_fd_properties(handle)
+ && (__fd_properties[handle]->flags & FILE_DESC_FILL_TEST))
+ {
+ if (_write_fill_seek_gap(handle) < 0)
+ return -1;
+ }
+
tbsize = _go32_info_block.size_of_transfer_buffer;
nput = 0;
do {
*************** _write(int handle, const void* buffer, s
*** 58,60 ****
--- 69,153 ----
return nput;
}
+
+ /* If the file pointer offset is beyond EOF, fill the gap between EOF and
+ the file pointer offset with zeroes. This emulates the behavior
described
+ in the POSIX documentation for lseek. */
+ int
+ _write_fill_seek_gap(int fd)
+ {
+ offset_t eof_off, cur_off, fill_count;
+ unsigned long tbsize, buf_size;
+ unsigned long i, write_size, out_count;
+ __dpmi_regs r;
+
+ __clear_fd_flags(fd, FILE_DESC_FILL_TEST);
+
+ if (isatty(fd))
+ return -1;
+
+ /* Quit when unable to get the file length. */
+ eof_off = lfilelength (fd);
+ if (eof_off < 0)
+ return -1;
+
+ /* Quit when unable to get the current file offset. */
+ cur_off = llseek (fd, 0, SEEK_CUR);
+ if (cur_off < 0)
+ return -1;
+
+ /* Quit (but return success) if the current offset is not past EOF. */
+ if (cur_off <= eof_off)
+ return 0;
+
+ /* Quit when unable to seek to EOF. */
+ if (llseek (fd, eof_off, SEEK_SET) == -1)
+ return -1;
+
+ /* Clear once again because the llseek call above will
+ set the fill test flag. */
+ __clear_fd_flags(fd, FILE_DESC_FILL_TEST);
+
+ /* Fill the transfer buffer with zeros. */
+ tbsize = _go32_info_block.size_of_transfer_buffer;
+ fill_count = cur_off - eof_off;
+
+ buf_size = (fill_count > tbsize) ? tbsize : fill_count;
+
+ i = 0;
+ _farsetsel(_dos_ds);
+ while (i < buf_size)
+ {
+ _farnspokel(__tb + i, 0);
+ i += 4;
+ }
+
+ /* Write out the zeros. */
+ out_count = 0;
+ do
+ {
+ r.x.ax = 0x4000;
+ r.x.bx = fd;
+ write_size = (fill_count > buf_size) ? buf_size : fill_count;
+ r.x.cx = write_size;
+ r.x.dx = __tb & 15;
+ r.x.ds = __tb / 16;
+ __dpmi_int (0x21, &r);
+ if (r.x.flags & 1)
+ {
+ errno =__doserr_to_errno (r.x.ax);
+ return -1;
+ }
+ fill_count -= r.x.ax;
+ out_count += r.x.ax;
+ } while (fill_count && (write_size == r.x.ax));
+
+ if (fill_count && out_count == 0)
+ {
+ errno = ENOSPC;
+ return -1;
+ }
+
+ return 0;
+ }
+
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