380 lines
9.0 KiB
C++
380 lines
9.0 KiB
C++
/* pipe.cc: pipe for Cygwin.
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Copyright 1996, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
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2007 Hat, Inc.
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This file is part of Cygwin.
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This software is a copyrighted work licensed under the terms of the
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Cygwin license. Please consult the file "CYGWIN_LICENSE" for
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details. */
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/* FIXME: Should this really be fhandler_pipe.cc? */
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#include "winsup.h"
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#include <unistd.h>
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#include <stdlib.h>
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#include <sys/socket.h>
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#include <limits.h>
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#include "cygerrno.h"
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#include "security.h"
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#include "path.h"
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#include "fhandler.h"
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#include "dtable.h"
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#include "cygheap.h"
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#include "thread.h"
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#include "pinfo.h"
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#include "cygthread.h"
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#include "ntdll.h"
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fhandler_pipe::fhandler_pipe ()
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: fhandler_base (), popen_pid (0)
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{
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get_overlapped ()->hEvent = NULL;
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need_fork_fixup (true);
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}
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extern "C" int sscanf (const char *, const char *, ...);
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int
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fhandler_pipe::open (int flags, mode_t mode)
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{
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HANDLE proc, pipe_hdl, nio_hdl = NULL;
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fhandler_pipe *fh = NULL;
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size_t size;
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int pid, rwflags = (flags & O_ACCMODE);
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bool inh;
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sscanf (get_name (), "/proc/%d/fd/pipe:[%d]", &pid, (int *) &pipe_hdl);
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if (pid == myself->pid)
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{
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cygheap_fdenum cfd (true);
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while (cfd.next () >= 0)
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{
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if (cfd->get_handle () != pipe_hdl)
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continue;
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if ((rwflags == O_RDONLY && !(cfd->get_access () & GENERIC_READ))
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|| (rwflags == O_WRONLY && !(cfd->get_access () & GENERIC_WRITE)))
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{
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set_errno (EACCES);
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return 0;
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}
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if (!cfd->dup (this))
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return 1;
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return 0;
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}
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set_errno (ENOENT);
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return 0;
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}
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pinfo p (pid);
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if (!p)
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{
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set_errno (ESRCH);
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return 0;
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}
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if (!(proc = OpenProcess (PROCESS_DUP_HANDLE, false, p->dwProcessId)))
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{
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__seterrno ();
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return 0;
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}
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if (!(fh = p->pipe_fhandler (pipe_hdl, size)) || !size)
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{
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set_errno (ENOENT);
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goto out;
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}
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/* Too bad, but Windows only allows the same access mode when dup'ing
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the pipe. */
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if ((rwflags == O_RDONLY && !(fh->get_access () & GENERIC_READ))
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|| (rwflags == O_WRONLY && !(fh->get_access () & GENERIC_WRITE)))
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{
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set_errno (EACCES);
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goto out;
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}
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inh = !(flags & O_NOINHERIT);
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if (!DuplicateHandle (proc, pipe_hdl, hMainProc, &nio_hdl,
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0, inh, DUPLICATE_SAME_ACCESS))
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{
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__seterrno ();
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goto out;
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}
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init (nio_hdl, fh->get_access (), mode & O_TEXT ?: O_BINARY);
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if (flags & O_NOINHERIT)
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close_on_exec (true);
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uninterruptible_io (fh->uninterruptible_io ());
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cfree (fh);
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CloseHandle (proc);
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return 1;
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out:
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if (nio_hdl)
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CloseHandle (nio_hdl);
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if (fh)
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free (fh);
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if (proc)
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CloseHandle (proc);
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return 0;
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}
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_off64_t
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fhandler_pipe::lseek (_off64_t offset, int whence)
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{
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debug_printf ("(%d, %d)", offset, whence);
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set_errno (ESPIPE);
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return -1;
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}
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int
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fhandler_pipe::fadvise (_off64_t offset, _off64_t length, int advice)
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{
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set_errno (ESPIPE);
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return -1;
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}
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int
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fhandler_pipe::ftruncate (_off64_t length, bool allow_truncate)
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{
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set_errno (allow_truncate ? EINVAL : ESPIPE);
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return -1;
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}
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char *
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fhandler_pipe::get_proc_fd_name (char *buf)
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{
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__small_sprintf (buf, "pipe:[%d]", get_handle ());
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return buf;
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}
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void __stdcall
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fhandler_pipe::read (void *in_ptr, size_t& in_len)
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{
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return read_overlapped (in_ptr, in_len);
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}
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int
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fhandler_pipe::write (const void *ptr, size_t len)
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{
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return write_overlapped (ptr, len);
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}
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int
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fhandler_pipe::dup (fhandler_base *child)
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{
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fhandler_pipe *ftp = (fhandler_pipe *) child;
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ftp->set_popen_pid (0);
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int res;
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if (get_handle () && fhandler_base::dup (child))
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res = -1;
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else
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res = 0;
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debug_printf ("res %d", res);
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return res;
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}
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/* Create a pipe, and return handles to the read and write ends,
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just like CreatePipe, but ensure that the write end permits
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FILE_READ_ATTRIBUTES access, on later versions of win32 where
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this is supported. This access is needed by NtQueryInformationFile,
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which is used to implement select and nonblocking writes.
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Note that the return value is either 0 or GetLastError,
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unlike CreatePipe, which returns a bool for success or failure. */
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int
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fhandler_pipe::create_selectable (LPSECURITY_ATTRIBUTES sa_ptr, HANDLE& r,
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HANDLE& w, DWORD psize)
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{
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/* Default to error. */
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r = w = INVALID_HANDLE_VALUE;
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/* Ensure that there is enough pipe buffer space for atomic writes. */
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if (psize < PIPE_BUF)
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psize = PIPE_BUF;
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char pipename[CYG_MAX_PATH];
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/* Retry CreateNamedPipe as long as the pipe name is in use.
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Retrying will probably never be necessary, but we want
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to be as robust as possible. */
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while (1)
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{
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static volatile ULONG pipe_unique_id;
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__small_sprintf (pipename, "\\\\.\\pipe\\cygwin-%p-%p", myself->pid,
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InterlockedIncrement ((LONG *) &pipe_unique_id));
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debug_printf ("CreateNamedPipe: name %s, size %lu", pipename, psize);
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/* Use CreateNamedPipe instead of CreatePipe, because the latter
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returns a write handle that does not permit FILE_READ_ATTRIBUTES
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access, on versions of win32 earlier than WinXP SP2.
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CreatePipe also stupidly creates a full duplex pipe, which is
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a waste, since only a single direction is actually used.
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It's important to only allow a single instance, to ensure that
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the pipe was not created earlier by some other process, even if
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the pid has been reused. We avoid FILE_FLAG_FIRST_PIPE_INSTANCE
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because that is only available for Win2k SP2 and WinXP. */
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r = CreateNamedPipe (pipename, PIPE_ACCESS_INBOUND | FILE_FLAG_OVERLAPPED,
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PIPE_TYPE_BYTE | PIPE_READMODE_BYTE, 1, psize,
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psize, NMPWAIT_USE_DEFAULT_WAIT, sa_ptr);
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/* Win 95 seems to return NULL instead of INVALID_HANDLE_VALUE */
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if (r && r != INVALID_HANDLE_VALUE)
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{
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debug_printf ("pipe read handle %p", r);
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break;
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}
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DWORD err = GetLastError ();
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switch (err)
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{
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case ERROR_PIPE_BUSY:
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/* The pipe is already open with compatible parameters.
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Pick a new name and retry. */
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debug_printf ("pipe busy, retrying");
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break;
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case ERROR_ACCESS_DENIED:
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/* The pipe is already open with incompatible parameters.
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Pick a new name and retry. */
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debug_printf ("pipe access denied, retrying");
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break;
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default:
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{
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err = GetLastError ();
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debug_printf ("CreatePipe failed, %E");
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return err;
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}
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}
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}
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debug_printf ("CreateFile: name %s", pipename);
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/* Open the named pipe for writing.
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Be sure to permit FILE_READ_ATTRIBUTES access. */
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w = CreateFile (pipename, GENERIC_WRITE | FILE_READ_ATTRIBUTES, 0, sa_ptr,
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OPEN_EXISTING, FILE_FLAG_OVERLAPPED, 0);
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if (!w || w == INVALID_HANDLE_VALUE)
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{
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/* Failure. */
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DWORD err = GetLastError ();
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debug_printf ("CreateFile failed, %E");
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CloseHandle (r);
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return err;
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}
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debug_printf ("pipe write handle %p", w);
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/* Success. */
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return 0;
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}
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int
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fhandler_pipe::create (fhandler_pipe *fhs[2], unsigned psize, int mode)
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{
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HANDLE r, w;
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SECURITY_ATTRIBUTES *sa = (mode & O_NOINHERIT) ? &sec_none_nih : &sec_none;
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int res = -1;
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int ret = create_selectable (sa, r, w, psize);
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if (ret)
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__seterrno_from_win_error (ret);
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else
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{
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fhs[0] = (fhandler_pipe *) build_fh_dev (*piper_dev);
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fhs[1] = (fhandler_pipe *) build_fh_dev (*pipew_dev);
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int binmode = mode & O_TEXT ?: O_BINARY;
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fhs[0]->init (r, GENERIC_READ, binmode);
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fhs[1]->init (w, GENERIC_WRITE, binmode);
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if (mode & O_NOINHERIT)
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{
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fhs[0]->close_on_exec (true);
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fhs[1]->close_on_exec (true);
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}
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fhs[0]->setup_overlapped ();
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fhs[1]->setup_overlapped ();
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res = 0;
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}
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syscall_printf ("%d = pipe ([%p, %p], %d, %p)", res, fhs[0], fhs[1], psize, mode);
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return res;
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}
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int
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fhandler_pipe::ioctl (unsigned int cmd, void *p)
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{
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int n;
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switch (cmd)
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{
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case FIONREAD:
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if (get_device () == FH_PIPEW)
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{
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set_errno (EINVAL);
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return -1;
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}
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if (!PeekNamedPipe (get_handle (), NULL, 0, NULL, (DWORD *) &n, NULL))
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{
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__seterrno ();
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return -1;
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}
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break;
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default:
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return fhandler_base::ioctl (cmd, p);
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break;
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}
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*(int *) p = n;
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return 0;
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}
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int __stdcall
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fhandler_pipe::fstatvfs (struct statvfs *sfs)
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{
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set_errno (EBADF);
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return -1;
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}
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#define DEFAULT_PIPEBUFSIZE (16 * PIPE_BUF)
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extern "C" int
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pipe (int filedes[2])
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{
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extern DWORD binmode;
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fhandler_pipe *fhs[2];
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int res = fhandler_pipe::create (fhs, DEFAULT_PIPEBUFSIZE,
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(!binmode || binmode == O_BINARY)
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? O_BINARY : O_TEXT);
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if (res == 0)
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{
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cygheap_fdnew fdin;
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cygheap_fdnew fdout (fdin, false);
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fdin = fhs[0];
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fdout = fhs[1];
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filedes[0] = fdin;
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filedes[1] = fdout;
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}
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return res;
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}
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extern "C" int
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_pipe (int filedes[2], unsigned int psize, int mode)
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{
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fhandler_pipe *fhs[2];
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int res = fhandler_pipe::create (fhs, psize, mode);
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/* This type of pipe is not interruptible so set the appropriate flag. */
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if (!res)
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{
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cygheap_fdnew fdin;
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cygheap_fdnew fdout (fdin, false);
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fhs[0]->uninterruptible_io (true);
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fdin = fhs[0];
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fdout = fhs[1];
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filedes[0] = fdin;
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filedes[1] = fdout;
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}
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return res;
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}
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