436 lines
11 KiB
C++
436 lines
11 KiB
C++
/* fhandler_pipe.cc: pipes for Cygwin.
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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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#include "shared_info.h"
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fhandler_pipe::fhandler_pipe ()
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: fhandler_base_overlapped (), popen_pid (0)
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{
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max_atomic_write = DEFAULT_PIPEBUFSIZE;
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need_fork_fixup (true);
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}
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int
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fhandler_pipe::init (HANDLE f, DWORD a, mode_t mode, int64_t uniq_id)
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{
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/* FIXME: Have to clean this up someday
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FIXME: Do we have to check for both !get_win32_name() and
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!*get_win32_name()? */
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if ((!get_win32_name () || !*get_win32_name ()) && get_name ())
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{
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char *d;
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const char *s;
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char *hold_normalized_name = (char *) alloca (strlen (get_name ()) + 1);
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for (s = get_name (), d = hold_normalized_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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fhandler_base::init (f, a, mode);
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close_on_exec (mode & O_CLOEXEC);
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set_ino (uniq_id);
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set_unique_id (uniq_id | !!(mode & GENERIC_WRITE));
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if (opened_properly)
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setup_overlapped ();
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else
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destroy_overlapped ();
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return 1;
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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, nio_hdl = NULL;
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int64_t uniq_id;
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fhandler_pipe *fh = NULL, *fhr = NULL, *fhw = 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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bool got_one = false;
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if (sscanf (get_name (), "/proc/%d/fd/pipe:[%llu]",
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&pid, (long long *) &uniq_id) < 2)
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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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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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/* Windows doesn't allow to copy a pipe HANDLE with another access
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mode. So we check for read and write side of pipe and try to
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find the one matching the requested access mode. */
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if (cfd->get_unique_id () == uniq_id)
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got_one = true;
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else if (cfd->get_unique_id () == uniq_id + 1)
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got_one = true;
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else
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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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continue;
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cfd->copyto (this);
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set_io_handle (NULL);
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pc.reset_conv_handle ();
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if (!cfd->dup (this, flags))
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return 1;
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return 0;
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}
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/* Found the pipe but access mode didn't match? EACCES.
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Otherwise ENOENT */
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set_errno (got_one ? EACCES : 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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fhr = p->pipe_fhandler (uniq_id, size);
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if (fhr && rwflags == O_RDONLY)
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fh = fhr;
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else
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{
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fhw = p->pipe_fhandler (uniq_id + 1, size);
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if (fhw && rwflags == O_WRONLY)
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fh = fhw;
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}
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if (!fh)
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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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set_errno (fhr || fhw ? EACCES : ENOENT);
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goto out;
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}
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inh = !(flags & O_CLOEXEC);
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if (!DuplicateHandle (proc, fh->get_handle (), GetCurrentProcess (),
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&nio_hdl, 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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fh->get_plain_ino ());
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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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off_t
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fhandler_pipe::lseek (off_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 (off_t offset, off_t length, int advice)
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{
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return ESPIPE;
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}
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int
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fhandler_pipe::ftruncate (off_t length, bool allow_truncate)
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{
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return allow_truncate ? EINVAL : ESPIPE;
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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:[%U]", get_plain_ino ());
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return buf;
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}
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int
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fhandler_pipe::dup (fhandler_base *child, int flags)
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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_overlapped::dup (child, flags))
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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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DWORD
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fhandler_pipe::create (LPSECURITY_ATTRIBUTES sa_ptr, PHANDLE r, PHANDLE w,
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DWORD psize, const char *name, DWORD open_mode,
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int64_t *unique_id)
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{
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/* Default to error. */
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if (r)
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*r = NULL;
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if (w)
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*w = NULL;
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/* Ensure that there is enough pipe buffer space for atomic writes. */
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if (!psize)
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psize = DEFAULT_PIPEBUFSIZE;
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char pipename[MAX_PATH];
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size_t len = __small_sprintf (pipename, PIPE_INTRO "%S-",
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&cygheap->installation_key);
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DWORD pipe_mode = PIPE_READMODE_BYTE | PIPE_REJECT_REMOTE_CLIENTS;
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if (!name)
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pipe_mode |= pipe_byte ? PIPE_TYPE_BYTE : PIPE_TYPE_MESSAGE;
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else
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pipe_mode |= PIPE_TYPE_MESSAGE;
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if (!name || (open_mode & PIPE_ADD_PID))
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{
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len += __small_sprintf (pipename + len, "%u-", GetCurrentProcessId ());
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open_mode &= ~PIPE_ADD_PID;
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}
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if (name)
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len += __small_sprintf (pipename + len, "%s", name);
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open_mode |= PIPE_ACCESS_INBOUND | FILE_FLAG_FIRST_PIPE_INSTANCE;
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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 = 0;
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while (r && !*r)
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{
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static volatile ULONG pipe_unique_id;
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if (!name)
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{
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LONG id = InterlockedIncrement ((LONG *) &pipe_unique_id);
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__small_sprintf (pipename + len, "pipe-%p", id);
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if (unique_id)
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*unique_id = ((int64_t) id << 32 | GetCurrentProcessId ());
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}
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debug_printf ("name %s, size %u, mode %s", pipename, psize,
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(pipe_mode & PIPE_TYPE_MESSAGE)
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? "PIPE_TYPE_MESSAGE" : "PIPE_TYPE_BYTE");
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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.
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Note that the write side of the pipe is opened as PIPE_TYPE_MESSAGE.
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This *seems* to more closely mimic Linux pipe behavior and is
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definitely required for pty handling since fhandler_pty_master
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writes to the pipe in chunks, terminated by newline when CANON mode
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is specified. */
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*r = CreateNamedPipe (pipename, open_mode, pipe_mode, 1, psize,
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psize, NMPWAIT_USE_DEFAULT_WAIT, sa_ptr);
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if (*r != INVALID_HANDLE_VALUE)
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{
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debug_printf ("pipe read handle %p", *r);
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err = 0;
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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", !name ? ", retrying" : "");
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if (!name)
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*r = NULL;
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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%s", !name ? ", retrying" : "");
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if (!name)
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*r = NULL;
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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 ("failed, %E");
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}
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}
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}
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if (err)
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{
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*r = NULL;
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return err;
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}
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if (!w)
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debug_printf ("pipe write handle NULL");
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else
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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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DWORD access = GENERIC_WRITE | FILE_READ_ATTRIBUTES;
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if ((open_mode & PIPE_ACCESS_DUPLEX) == PIPE_ACCESS_DUPLEX)
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access |= GENERIC_READ | FILE_WRITE_ATTRIBUTES;
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*w = CreateFile (pipename, access, 0, sa_ptr, OPEN_EXISTING,
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open_mode & 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, r %p, %E", r);
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if (r)
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CloseHandle (*r);
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*w = NULL;
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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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}
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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 = sec_none_cloexec (mode);
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int res = -1;
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int64_t unique_id;
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int ret = create (sa, &r, &w, psize, NULL, FILE_FLAG_OVERLAPPED, &unique_id);
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if (ret)
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__seterrno_from_win_error (ret);
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else if ((fhs[0] = (fhandler_pipe *) build_fh_dev (*piper_dev)) == NULL)
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{
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CloseHandle (r);
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CloseHandle (w);
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}
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else if ((fhs[1] = (fhandler_pipe *) build_fh_dev (*pipew_dev)) == NULL)
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{
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delete fhs[0];
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CloseHandle (w);
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}
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else
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{
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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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unique_id);
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fhs[1]->init (w, FILE_CREATE_PIPE_INSTANCE | GENERIC_WRITE, mode,
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unique_id);
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res = 0;
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}
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debug_printf ("%R = pipe([%p, %p], %d, %y)", 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 __reg2
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fhandler_pipe::fstat (struct stat *buf)
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{
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int ret = fhandler_base::fstat (buf);
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if (!ret)
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{
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buf->st_dev = FH_PIPE;
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if (!(buf->st_ino = get_plain_ino ()))
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sscanf (get_name (), "/proc/%*d/fd/pipe:[%llu]",
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(long long *) &buf->st_ino);
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}
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return ret;
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}
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int __reg2
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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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