532 lines
12 KiB
C++
532 lines
12 KiB
C++
/* pipe.cc: pipe for Cygwin.
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Copyright 1996, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007,
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2008 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 <stdlib.h>
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#include <sys/socket.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 "pinfo.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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struct pipesync
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{
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bool reader;
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HANDLE ev, non_cygwin_h, ret_handle;
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pipesync(HANDLE, DWORD);
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int operator == (int x) const {return !!ev;}
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static DWORD WINAPI handler (LPVOID *);
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};
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inline bool
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getov_result (HANDLE h, DWORD& nbytes, LPOVERLAPPED ov)
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{
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if (ov && (GetLastError () != ERROR_IO_PENDING
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|| !GetOverlappedResult (h, ov, &nbytes, true)))
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{
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__seterrno ();
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return false;
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}
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return true;
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}
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static DWORD WINAPI
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pipe_handler (LPVOID in_ps)
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{
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pipesync ps = *(pipesync *) in_ps;
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HANDLE h, in, out;
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DWORD err = fhandler_pipe::create_selectable (&sec_none_nih, in, out, 0);
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if (err)
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{
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SetLastError (err);
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system_printf ("couldn't create a shadow pipe for non-cygwin pipe I/O, %E");
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return 0;
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}
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h = ((pipesync *) in_ps)->ret_handle = ps.reader ? in : out;
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SetHandleInformation (h, HANDLE_FLAG_INHERIT, HANDLE_FLAG_INHERIT);
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SetEvent (ps.ev);
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char buf[4096];
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DWORD read_bytes, write_bytes;
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HANDLE hread, hwrite, hclose;
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OVERLAPPED ov, *rov, *wov;
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memset (&ov, 0, sizeof (ov));
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ov.hEvent = CreateEvent (&sec_none_nih, true, false, NULL);
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if (ps.reader)
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{
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hread = ps.non_cygwin_h;
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hclose = hwrite = out;
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wov = &ov;
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rov = NULL;
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}
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else
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{
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hclose = hread = in;
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hwrite = ps.non_cygwin_h;
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rov = &ov;
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wov = NULL;
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}
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while (1)
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{
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ResetEvent (ov.hEvent);
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BOOL res = ReadFile (hread, buf, 4096, &read_bytes, rov);
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if (!res && !getov_result (hread, read_bytes, rov))
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break;
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if (!read_bytes)
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break;
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res = WriteFile (hwrite, buf, read_bytes, &write_bytes, wov);
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if (!res && !getov_result (hwrite, write_bytes, wov))
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break;
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if (write_bytes != read_bytes)
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break;
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}
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err = GetLastError ();
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CloseHandle (ov.hEvent);
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CloseHandle (hclose);
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CloseHandle (ps.non_cygwin_h);
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SetLastError (err);
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return 0;
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}
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pipesync::pipesync (HANDLE f, DWORD is_reader):
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reader (false), ret_handle (NULL)
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{
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ev = CreateEvent (&sec_none_nih, true, false, NULL);
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if (!ev)
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{
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system_printf ("couldn't create synchronization event for non-cygwin pipe, %E");
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goto out;
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}
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debug_printf ("created thread synchronization event %p", ev);
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non_cygwin_h = f;
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reader = !!is_reader;
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ret_handle = NULL;
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DWORD tid;
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HANDLE ht = CreateThread (&sec_none_nih, 0, pipe_handler, this, 0, &tid);
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if (!ht)
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goto out;
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CloseHandle (ht);
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switch (WaitForSingleObject (ev, INFINITE))
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{
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case WAIT_OBJECT_0:
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break;
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default:
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system_printf ("WFSO failed waiting for synchronization event for non-cygwin pipe, %E");
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break;
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}
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out:
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if (ev)
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{
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CloseHandle (ev);
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ev = NULL;
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}
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return;
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}
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void
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fhandler_pipe::init (HANDLE f, DWORD a, mode_t mode)
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{
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// FIXME: Have to clean this up someday
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if (!*get_win32_name () && get_name ())
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{
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char *hold_normalized_name = (char *) alloca (strlen (get_name ()) + 1);
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strcpy (hold_normalized_name, get_name ());
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char *s, *d;
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for (s = hold_normalized_name, d = (char *) get_win32_name (); *s; s++, d++)
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if (*s == '/')
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*d = '\\';
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else
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*d = *s;
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*d = '\0';
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set_name (hold_normalized_name);
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}
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bool opened_properly = a & FILE_CREATE_PIPE_INSTANCE;
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a &= ~FILE_CREATE_PIPE_INSTANCE;
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if (!opened_properly)
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{
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pipesync ps (f, a & GENERIC_READ);
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f = ps.ret_handle;
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}
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fhandler_base::init (f, a, mode);
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if (mode & O_NOINHERIT)
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close_on_exec (true);
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setup_overlapped ();
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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::raw_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::raw_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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#define PIPE_INTRO "\\\\.\\pipe\\cygwin-"
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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, const char *name)
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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[MAX_PATH] = PIPE_INTRO;
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/* FIXME: Eventually make ttys work with overlapped I/O. */
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DWORD overlapped = name ? 0 : FILE_FLAG_OVERLAPPED;
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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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DWORD err;
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do
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{
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static volatile ULONG pipe_unique_id;
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if (!name)
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__small_sprintf (pipename + strlen(PIPE_INTRO), "%p-%p", myself->pid,
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InterlockedIncrement ((LONG *) &pipe_unique_id));
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else
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strcpy (pipename + strlen(PIPE_INTRO), name);
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debug_printf ("CreateNamedPipe: name %s, size %lu", pipename, psize);
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err = 0;
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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 | 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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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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while (!name);
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if (err)
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return err;
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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, 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;
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int ret = create_selectable (sa, r, w, psize);
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if (ret)
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{
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__seterrno_from_win_error (ret);
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res = -1;
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}
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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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mode |= mode & O_TEXT ?: O_BINARY;
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fhs[0]->init (r, FILE_CREATE_PIPE_INSTANCE | GENERIC_READ, mode);
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fhs[1]->init (w, FILE_CREATE_PIPE_INSTANCE | GENERIC_WRITE, mode);
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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 65536
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extern "C" int
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pipe (int filedes[2])
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{
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fhandler_pipe *fhs[2];
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int res = fhandler_pipe::create (fhs, DEFAULT_PIPEBUFSIZE, O_BINARY);
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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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