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* fhandler.cc (fhandler_base_overlapped::wait_overlapped): Remove special

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treatment for ERROR_NO_SYSTEM_RESOURCES.  Cancel I/O and reset the overlapped
handle on error.
(fhandler_base_overlapped::write_overlapped): Limit writes to max_atomic_write
bytes in blocking case.  Incorporate code from now-defunct
write_overlapped_fallback.  Fix serious oversight where ptr was not advanced as
buffer was written.
(fhandler_base_overlapped::write_overlapped_fallback): Eliminate.
* fhandler.h (fhandler_base_overlapped::write_overlapped_fallback): Ditto for
declaration.
(DEFAULT_PIPEBUFSIZE): Lower size to slightly less than documented worst-case
atomic write size.
(fhandler_overlapped::wait_return): Remove unused element.
This commit is contained in:
Christopher Faylor
2011-03-13 20:20:58 +00:00
parent 7a9064faa5
commit 9636c4262e
3 changed files with 56 additions and 83 deletions
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115
winsup/cygwin/fhandler.cc
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@@ -1733,9 +1733,7 @@ fhandler_base_overlapped::wait_overlapped (bool inres, bool writing, DWORD *byte
wait_return res;
DWORD err = GetLastError ();
if (err == ERROR_NO_SYSTEM_RESOURCES)
res = overlapped_fallback;
else if (nonblocking)
if (nonblocking)
{
if (!inres && err != ERROR_IO_PENDING)
res = overlapped_error;
@@ -1806,6 +1804,9 @@ fhandler_base_overlapped::wait_overlapped (bool inres, bool writing, DWORD *byte
else
{
debug_printf ("err %u", err);
HANDLE h = writing ? get_output_handle () : get_handle ();
CancelIo (h);
ResetEvent (get_overlapped ());
__seterrno_from_win_error (err);
*bytes = (DWORD) -1;
}
@@ -1836,7 +1837,6 @@ fhandler_base_overlapped::read_overlapped (void *ptr, size_t& len)
default: /* Added to quiet gcc */
case overlapped_success:
case overlapped_error:
case overlapped_fallback:
keep_looping = false;
break;
}
@@ -1849,92 +1849,51 @@ fhandler_base_overlapped::read_overlapped (void *ptr, size_t& len)
ssize_t __stdcall __attribute__ ((regparm (3)))
fhandler_base_overlapped::write_overlapped (const void *ptr, size_t len)
{
DWORD nbytes;
size_t nbytes;
if (has_ongoing_io ())
nbytes = (DWORD) -1;
else
{
int last_errno = get_errno ();
bool keep_looping;
if (is_nonblocking () && max_atomic_write && len > max_atomic_write)
len = max_atomic_write;
do
size_t chunk;
if (!max_atomic_write || len < max_atomic_write)
chunk = len;
else if (is_nonblocking ())
chunk = len = max_atomic_write;
else
chunk = max_atomic_write;
nbytes = 0;
DWORD nbytes_now = 0;
/* Write to fd in smaller chunks, accumlating a total.
If there's an error, just return the accumulated total
unless the first write fails, in which case return value
from wait_overlapped(). */
while (nbytes < len)
{
bool res = WriteFile (get_output_handle (), ptr, len, &nbytes,
size_t left = len - nbytes;
size_t len1;
if (left > chunk)
len1 = chunk;
else
len1 = left;
bool res = WriteFile (get_output_handle (), ptr, len1, &nbytes_now,
get_overlapped ());
switch (wait_overlapped (res, true, &nbytes, is_nonblocking (), (size_t) len))
switch (wait_overlapped (res, true, &nbytes_now,
is_nonblocking (), len1))
{
case overlapped_signal:
keep_looping = true;
break;
case overlapped_fallback:
set_errno (last_errno); /* Avoid setting a random EFBIG errno */
nbytes = write_overlapped_fallback (ptr, len);
/* fall through intentionally */;
default: /* Added to quiet gcc */
case overlapped_success:
ptr = ((char *) ptr) + chunk;
nbytes += nbytes_now;
/* fall through intentionally */
case overlapped_signal:
break; /* keep looping */
case overlapped_error:
keep_looping = false;
len = 0; /* terminate loop */
break;
}
}
while (keep_looping);
if (!nbytes)
nbytes = nbytes_now;
}
debug_printf ("returning %u", nbytes);
return nbytes;
}
/* On XP (at least) the size of the buffer that can be used to write to a pipe
(pipes are currently the only thing using the overlapped methods) is
limited. This function is a fallback for when that problem is detected.
It writes to the pipe using smaller buffers but masks this behavior
to the caller. */
ssize_t __stdcall __attribute__ ((regparm (3)))
fhandler_base_overlapped::write_overlapped_fallback (const void *ptr, size_t orig_len)
{
size_t chunk;
/* So far, in testing, only the first if test has been necessary */
if (orig_len > MAX_OVERLAPPED_WRITE_LEN)
chunk = MAX_OVERLAPPED_WRITE_LEN;
else if (orig_len > MIN_OVERLAPPED_WRITE_LEN)
chunk = MIN_OVERLAPPED_WRITE_LEN;
else
chunk = orig_len / 4;
ssize_t nbytes = 0;
DWORD nbytes_now = 0;
/* Write to fd in smaller chunks, accumlating a total.
If there's an error, just return the accumulated total
unless the first write fails, in which case return value
from wait_overlapped(). */
while ((size_t) nbytes < orig_len)
{
size_t left = orig_len - nbytes;
size_t len;
if (left > chunk)
len = chunk;
else
len = left;
bool res = WriteFile (get_output_handle (), ptr, len, &nbytes_now,
get_overlapped ());
/* The nonblocking case is not going to be used currently and may
eventually disappear. */
switch (wait_overlapped (res, true, &nbytes_now,
left <= chunk ? is_nonblocking () : false,
(size_t) len))
{
case overlapped_success:
nbytes += nbytes_now;
/* fall through intentionally */
case overlapped_signal:
break; /* keep looping */
case overlapped_error:
case overlapped_fallback: /* XXX Could make this more adaptive
if needed */
orig_len = 0; /* terminate loop */
break;
}
}
if (!nbytes)
nbytes = nbytes_now;
return nbytes;
}