/* pipe.cc: pipe for Cygwin. Copyright 1996, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 Hat, Inc. This file is part of Cygwin. This software is a copyrighted work licensed under the terms of the Cygwin license. Please consult the file "CYGWIN_LICENSE" for details. */ /* FIXME: Should this really be fhandler_pipe.cc? */ #include "winsup.h" #include #include #include "cygerrno.h" #include "security.h" #include "path.h" #include "fhandler.h" #include "dtable.h" #include "cygheap.h" #include "pinfo.h" #include "shared_info.h" fhandler_pipe::fhandler_pipe () : fhandler_base_overlapped (), popen_pid (0) { need_fork_fixup (true); uninterruptible_io (true); } int fhandler_pipe::init (HANDLE f, DWORD a, mode_t mode) { /* FIXME: Have to clean this up someday FIXME: Do we have to check for both !get_win32_name() and !*get_win32_name()? */ if ((!get_win32_name () || !*get_win32_name ()) && get_name ()) { char *d; const char *s; char *hold_normalized_name = (char *) alloca (strlen (get_name ()) + 1); for (s = get_name (), d = hold_normalized_name; *s; s++, d++) if (*s == '/') *d = '\\'; else *d = *s; *d = '\0'; set_name (hold_normalized_name); } bool opened_properly = a & FILE_CREATE_PIPE_INSTANCE; a &= ~FILE_CREATE_PIPE_INSTANCE; fhandler_base::init (f, a, mode); close_on_exec (mode & O_CLOEXEC); setup_overlapped (opened_properly); return 1; } extern "C" int sscanf (const char *, const char *, ...); int fhandler_pipe::open (int flags, mode_t mode) { HANDLE proc, pipe_hdl, nio_hdl = NULL; fhandler_pipe *fh = NULL; size_t size; int pid, rwflags = (flags & O_ACCMODE); bool inh; sscanf (get_name (), "/proc/%d/fd/pipe:[%d]", &pid, (int *) &pipe_hdl); if (pid == myself->pid) { cygheap_fdenum cfd (true); while (cfd.next () >= 0) { if (cfd->get_handle () != pipe_hdl) continue; if ((rwflags == O_RDONLY && !(cfd->get_access () & GENERIC_READ)) || (rwflags == O_WRONLY && !(cfd->get_access () & GENERIC_WRITE))) { set_errno (EACCES); return 0; } if (!cfd->dup (this)) return 1; return 0; } set_errno (ENOENT); return 0; } pinfo p (pid); if (!p) { set_errno (ESRCH); return 0; } if (!(proc = OpenProcess (PROCESS_DUP_HANDLE, false, p->dwProcessId))) { __seterrno (); return 0; } if (!(fh = p->pipe_fhandler (pipe_hdl, size)) || !size) { set_errno (ENOENT); goto out; } /* Too bad, but Windows only allows the same access mode when dup'ing the pipe. */ if ((rwflags == O_RDONLY && !(fh->get_access () & GENERIC_READ)) || (rwflags == O_WRONLY && !(fh->get_access () & GENERIC_WRITE))) { set_errno (EACCES); goto out; } inh = !(flags & O_CLOEXEC); if (!DuplicateHandle (proc, pipe_hdl, GetCurrentProcess (), &nio_hdl, 0, inh, DUPLICATE_SAME_ACCESS)) { __seterrno (); goto out; } init (nio_hdl, fh->get_access (), mode & O_TEXT ?: O_BINARY); uninterruptible_io (fh->uninterruptible_io ()); cfree (fh); CloseHandle (proc); return 1; out: if (nio_hdl) CloseHandle (nio_hdl); if (fh) free (fh); if (proc) CloseHandle (proc); return 0; } _off64_t fhandler_pipe::lseek (_off64_t offset, int whence) { debug_printf ("(%d, %d)", offset, whence); set_errno (ESPIPE); return -1; } int fhandler_pipe::fadvise (_off64_t offset, _off64_t length, int advice) { set_errno (ESPIPE); return -1; } int fhandler_pipe::ftruncate (_off64_t length, bool allow_truncate) { set_errno (allow_truncate ? EINVAL : ESPIPE); return -1; } char * fhandler_pipe::get_proc_fd_name (char *buf) { __small_sprintf (buf, "pipe:[%d]", get_handle ()); return buf; } void fhandler_pipe::raw_read (void *in_ptr, size_t& in_len) { return read_overlapped (in_ptr, in_len); } int fhandler_pipe::raw_write (const void *ptr, size_t len) { return write_overlapped (ptr, len); } int fhandler_pipe::dup (fhandler_base *child) { fhandler_pipe *ftp = (fhandler_pipe *) child; ftp->set_popen_pid (0); int res; if (get_handle () && fhandler_base::dup (child)) res = -1; else res = 0; debug_printf ("res %d", res); return res; } #define PIPE_INTRO "\\\\.\\pipe\\cygwin-" /* Create a pipe, and return handles to the read and write ends, just like CreatePipe, but ensure that the write end permits FILE_READ_ATTRIBUTES access, on later versions of win32 where this is supported. This access is needed by NtQueryInformationFile, which is used to implement select and nonblocking writes. Note that the return value is either 0 or GetLastError, unlike CreatePipe, which returns a bool for success or failure. */ int fhandler_pipe::create_selectable (LPSECURITY_ATTRIBUTES sa_ptr, HANDLE& r, HANDLE& w, DWORD psize, const char *name) { /* Default to error. */ r = w = INVALID_HANDLE_VALUE; /* Ensure that there is enough pipe buffer space for atomic writes. */ if (psize < PIPE_BUF) psize = PIPE_BUF; char pipename[MAX_PATH]; const size_t len = __small_sprintf (pipename, PIPE_INTRO "%S-", &installation_key); /* FIXME: Eventually make ttys work with overlapped I/O. */ DWORD overlapped = name ? 0 : FILE_FLAG_OVERLAPPED; /* Retry CreateNamedPipe as long as the pipe name is in use. Retrying will probably never be necessary, but we want to be as robust as possible. */ DWORD err; do { static volatile ULONG pipe_unique_id; if (!name) __small_sprintf (pipename + len, "pipe-%p-%p", myself->pid, InterlockedIncrement ((LONG *) &pipe_unique_id)); else strcpy (pipename + len, name); debug_printf ("CreateNamedPipe: name %s, size %lu", pipename, psize); err = 0; /* Use CreateNamedPipe instead of CreatePipe, because the latter returns a write handle that does not permit FILE_READ_ATTRIBUTES access, on versions of win32 earlier than WinXP SP2. CreatePipe also stupidly creates a full duplex pipe, which is a waste, since only a single direction is actually used. It's important to only allow a single instance, to ensure that the pipe was not created earlier by some other process, even if the pid has been reused. We avoid FILE_FLAG_FIRST_PIPE_INSTANCE because that is only available for Win2k SP2 and WinXP. */ r = CreateNamedPipe (pipename, PIPE_ACCESS_INBOUND | overlapped, PIPE_TYPE_BYTE | PIPE_READMODE_BYTE, 1, psize, psize, NMPWAIT_USE_DEFAULT_WAIT, sa_ptr); /* Win 95 seems to return NULL instead of INVALID_HANDLE_VALUE */ if (r != INVALID_HANDLE_VALUE) { debug_printf ("pipe read handle %p", r); break; } err = GetLastError (); switch (err) { case ERROR_PIPE_BUSY: /* The pipe is already open with compatible parameters. Pick a new name and retry. */ debug_printf ("pipe busy", name ? ", retrying" : ""); break; case ERROR_ACCESS_DENIED: /* The pipe is already open with incompatible parameters. Pick a new name and retry. */ debug_printf ("pipe access denied%s", name ? ", retrying" : ""); break; default: { err = GetLastError (); debug_printf ("CreatePipe failed, %E"); return err; } } } while (!name); if (err) return err; debug_printf ("CreateFile: name %s", pipename); /* Open the named pipe for writing. Be sure to permit FILE_READ_ATTRIBUTES access. */ w = CreateFile (pipename, GENERIC_WRITE | FILE_READ_ATTRIBUTES, 0, sa_ptr, OPEN_EXISTING, overlapped, 0); if (!w || w == INVALID_HANDLE_VALUE) { /* Failure. */ DWORD err = GetLastError (); debug_printf ("CreateFile failed, %E"); CloseHandle (r); return err; } debug_printf ("pipe write handle %p", w); /* Success. */ return 0; } int fhandler_pipe::create (fhandler_pipe *fhs[2], unsigned psize, int mode) { HANDLE r, w; SECURITY_ATTRIBUTES *sa = sec_none_cloexec (mode); int res; int ret = create_selectable (sa, r, w, psize); if (ret) { __seterrno_from_win_error (ret); res = -1; } else { fhs[0] = (fhandler_pipe *) build_fh_dev (*piper_dev); fhs[1] = (fhandler_pipe *) build_fh_dev (*pipew_dev); mode |= mode & O_TEXT ?: O_BINARY; fhs[0]->init (r, FILE_CREATE_PIPE_INSTANCE | GENERIC_READ, mode); fhs[1]->init (w, FILE_CREATE_PIPE_INSTANCE | GENERIC_WRITE, mode); res = 0; } syscall_printf ("%d = pipe ([%p, %p], %d, %p)", res, fhs[0], fhs[1], psize, mode); return res; } int fhandler_pipe::ioctl (unsigned int cmd, void *p) { int n; switch (cmd) { case FIONREAD: if (get_device () == FH_PIPEW) { set_errno (EINVAL); return -1; } if (!PeekNamedPipe (get_handle (), NULL, 0, NULL, (DWORD *) &n, NULL)) { __seterrno (); return -1; } break; default: return fhandler_base::ioctl (cmd, p); break; } *(int *) p = n; return 0; } int __stdcall fhandler_pipe::fstatvfs (struct statvfs *sfs) { set_errno (EBADF); return -1; } #define DEFAULT_PIPEBUFSIZE 65536 extern "C" int pipe (int filedes[2]) { fhandler_pipe *fhs[2]; int res = fhandler_pipe::create (fhs, DEFAULT_PIPEBUFSIZE, O_BINARY); if (res == 0) { cygheap_fdnew fdin; cygheap_fdnew fdout (fdin, false); char buf[sizeof ("/dev/fd/pipe:[2147483647]")]; __small_sprintf (buf, "/dev/fd/pipe:[%d]", (int) fdin); fhs[0]->pc.set_normalized_path (buf); __small_sprintf (buf, "pipe:[%d]", (int) fdout); fhs[1]->pc.set_normalized_path (buf); fdin = fhs[0]; fdout = fhs[1]; filedes[0] = fdin; filedes[1] = fdout; } return res; } extern "C" int _pipe (int filedes[2], unsigned int psize, int mode) { fhandler_pipe *fhs[2]; int res = fhandler_pipe::create (fhs, psize, mode); /* This type of pipe is not interruptible so set the appropriate flag. */ if (!res) { cygheap_fdnew fdin; cygheap_fdnew fdout (fdin, false); fhs[0]->uninterruptible_io (true); fdin = fhs[0]; fdout = fhs[1]; filedes[0] = fdin; filedes[1] = fdout; } return res; } extern "C" int pipe2 (int filedes[2], int mode) { return _pipe (filedes, DEFAULT_PIPEBUFSIZE, mode); }