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Christopher Faylor <cgf@timesys.com>

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* autoload.cc (NtQueryInformationFile): Return nonzero on error.
* ntdll.h (FILE_PIPE_LOCAL_INFORMATION): Add.
(NtQueryInformationFile): Fix types for last two arguments.
* pipe.cc: Include stdlib.h, limits.h, and ntdll.h.
(create_selectable_pipe): New function to create a pipe that can be used with
NtQueryInformationFile for select.
(fhandler_pipe::create): Call create_selectable_pipe instead of CreatePipe.
(pipe): Use DEFAULT_PIPEBUFSIZE as argument to create_pipe.
* select.cc: Include limits.h and ntdll.h.
(peek_pipe): Add select_printf output.  Call NtQueryInformationFile to
implement select for write on pipes.
(fhandler_pipe::select_read): Reorder field assignments to be consistent with
fhandler_pipe::select_write.
(fhandler_pipe::select_write): Initialize startup, verify, cleanup, and
write_ready fields for select_record.
(fhandler_pipe::select_except): Tweak indentation to be consistent with
fhandler_pipe::select_write.
This commit is contained in:
Christopher Faylor
2004-09-03 01:32:02 +00:00
parent 79eebb79a6
commit 6644c628f5
5 changed files with 250 additions and 21 deletions
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138
winsup/cygwin/pipe.cc
View File

@@ -12,7 +12,9 @@ details. */
#include "winsup.h"
#include <unistd.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <limits.h>
#include "cygerrno.h"
#include "security.h"
#include "path.h"
@@ -22,6 +24,7 @@ details. */
#include "thread.h"
#include "pinfo.h"
#include "cygthread.h"
#include "ntdll.h"
static unsigned pipecount;
static const NO_COPY char pipeid_fmt[] = "stupid_pipe.%u.%u";
@@ -211,15 +214,139 @@ leave:
return res;
}
/* Create a pipe, and return handles to the read and write ends,
just like CreatePipe, but ensure that the write end permits
FILE_READ_ATTRIBUTES access, on later versions of win32 where
this is supported. This access is needed by NtQueryInformationFile,
which is used to implement select and nonblocking writes.
Note that the return value is either NO_ERROR or GetLastError,
unlike CreatePipe, which returns a bool for success or failure. */
static int
create_selectable_pipe (PHANDLE read_pipe_ptr,
PHANDLE write_pipe_ptr,
LPSECURITY_ATTRIBUTES sa_ptr,
DWORD psize)
{
/* Default to error. */
*read_pipe_ptr = *write_pipe_ptr = INVALID_HANDLE_VALUE;
HANDLE read_pipe = INVALID_HANDLE_VALUE, write_pipe = INVALID_HANDLE_VALUE;
/* Ensure that there is enough pipe buffer space for atomic writes. */
if (psize < PIPE_BUF)
psize = PIPE_BUF;
char pipename[CYG_MAX_PATH];
/* Retry CreateNamedPipe as long as the pipe name is in use.
Retrying will probably never be necessary, but we want
to be as robust as possible. */
while (1)
{
static volatile LONG pipe_unique_id;
__small_sprintf (pipename, "\\\\.\\pipe\\cygwin-%d-%ld", myself->pid,
InterlockedIncrement ((LONG *) &pipe_unique_id));
debug_printf ("CreateNamedPipe: name %s, size %lu", pipename, psize);
/* Use CreateNamedPipe instead of CreatePipe, because the latter
returns a write handle that does not permit FILE_READ_ATTRIBUTES
access, on versions of win32 earlier than WinXP SP2.
CreatePipe also stupidly creates a full duplex pipe, which is
a waste, since only a single direction is actually used.
It's important to only allow a single instance, to ensure that
the pipe was not created earlier by some other process, even if
the pid has been reused. We avoid FILE_FLAG_FIRST_PIPE_INSTANCE
because that is only available for Win2k SP2 and WinXP. */
read_pipe = CreateNamedPipe (pipename,
PIPE_ACCESS_INBOUND,
PIPE_TYPE_BYTE | PIPE_READMODE_BYTE,
1, /* max instances */
psize, /* output buffer size */
psize, /* input buffer size */
NMPWAIT_USE_DEFAULT_WAIT,
sa_ptr);
if (read_pipe != INVALID_HANDLE_VALUE)
{
debug_printf ("pipe read handle %p", read_pipe);
break;
}
DWORD err = GetLastError ();
switch (err)
{
case ERROR_PIPE_BUSY:
/* The pipe is already open with compatible parameters.
Pick a new name and retry. */
debug_printf ("pipe busy, retrying");
continue;
case ERROR_ACCESS_DENIED:
/* The pipe is already open with incompatible parameters.
Pick a new name and retry. */
debug_printf ("pipe access denied, retrying");
continue;
case ERROR_CALL_NOT_IMPLEMENTED:
/* We are on an older Win9x platform without named pipes.
Return an anonymous pipe as the best approximation. */
debug_printf ("CreateNamedPipe not implemented, resorting to "
"CreatePipe size %lu", psize);
if (CreatePipe (read_pipe_ptr, write_pipe_ptr, sa_ptr, psize))
{
debug_printf ("pipe read handle %p", *read_pipe_ptr);
debug_printf ("pipe write handle %p", *write_pipe_ptr);
return NO_ERROR;
}
err = GetLastError ();
debug_printf ("CreatePipe failed, %E");
return err;
default:
debug_printf ("CreateNamedPipe failed, %E");
return err;
}
/* NOTREACHED */
}
debug_printf ("CreateFile: name %s", pipename);
/* Open the named pipe for writing.
Be sure to permit FILE_READ_ATTRIBUTES access. */
write_pipe = CreateFile (pipename,
GENERIC_WRITE | FILE_READ_ATTRIBUTES,
0, /* share mode */
sa_ptr,
OPEN_EXISTING,
0, /* flags and attributes */
0); /* handle to template file */
if (write_pipe == INVALID_HANDLE_VALUE)
{
/* Failure. */
DWORD err = GetLastError ();
debug_printf ("CreateFile failed, %E");
CloseHandle (read_pipe);
return err;
}
debug_printf ("pipe write handle %p", write_pipe);
/* Success. */
*read_pipe_ptr = read_pipe;
*write_pipe_ptr = write_pipe;
return NO_ERROR;
}
int
fhandler_pipe::create (fhandler_pipe *fhs[2], unsigned psize, int mode, bool fifo)
{
HANDLE r, w;
SECURITY_ATTRIBUTES *sa = (mode & O_NOINHERIT) ? &sec_none_nih : &sec_none;
int res = -1;
int ret;
if (!CreatePipe (&r, &w, sa, psize))
__seterrno ();
if ((ret = create_selectable_pipe (&r, &w, sa, psize)) != NO_ERROR)
__seterrno_from_win_error (ret);
else
{
fhs[0] = (fhandler_pipe *) build_fh_dev (*piper_dev);
@@ -282,13 +409,16 @@ fhandler_pipe::ioctl (unsigned int cmd, void *p)
return 0;
}
#define DEFAULT_PIPEBUFSIZE (4 * PIPE_BUF)
extern "C" int
pipe (int filedes[2])
{
extern DWORD binmode;
fhandler_pipe *fhs[2];
int res = fhandler_pipe::create (fhs, 16384, (!binmode || binmode == O_BINARY)
? O_BINARY : O_TEXT);
int res = fhandler_pipe::create (fhs, DEFAULT_PIPEBUFSIZE,
(!binmode || binmode == O_BINARY)
? O_BINARY : O_TEXT);
if (res == 0)
{
cygheap_fdnew fdin;