diff options
Diffstat (limited to 'winsup/cygwin/pipe.cc')
| -rw-r--r-- | winsup/cygwin/pipe.cc | 544 |
1 files changed, 544 insertions, 0 deletions
diff --git a/winsup/cygwin/pipe.cc b/winsup/cygwin/pipe.cc new file mode 100644 index 00000000000..a6171f2f9e7 --- /dev/null +++ b/winsup/cygwin/pipe.cc @@ -0,0 +1,544 @@ +/* pipe.cc: pipe for Cygwin. + + Copyright 1996, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006 + 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 <unistd.h> +#include <stdlib.h> +#include <sys/socket.h> +#include <limits.h> +#include "cygerrno.h" +#include "security.h" +#include "path.h" +#include "fhandler.h" +#include "dtable.h" +#include "cygheap.h" +#include "thread.h" +#include "pinfo.h" +#include "cygthread.h" +#include "ntdll.h" + +static unsigned pipecount; +static const NO_COPY char pipeid_fmt[] = "stupid_pipe.%u.%u"; + +fhandler_pipe::fhandler_pipe () + : fhandler_base (), guard (NULL), broken_pipe (false), writepipe_exists (NULL), + orig_pid (0), id (0) +{ + need_fork_fixup (true); +} + +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_NOINHERIT); + if (!DuplicateHandle (proc, pipe_hdl, hMainProc, &nio_hdl, + 0, inh, DUPLICATE_SAME_ACCESS)) + { + __seterrno (); + goto out; + } + if (!fh->guard) + /* nothing to do */; + else if (DuplicateHandle (proc, fh->guard, hMainProc, &guard, + 0, inh, DUPLICATE_SAME_ACCESS)) + ProtectHandle (guard); + else + { + __seterrno (); + goto out; + } + if (!fh->writepipe_exists) + /* nothing to do */; + else if (!DuplicateHandle (proc, fh->writepipe_exists, + hMainProc, &writepipe_exists, + 0, inh, DUPLICATE_SAME_ACCESS)) + { + __seterrno (); + goto out; + } + if (fh->read_state) + create_read_state (2); + init (nio_hdl, fh->get_access (), mode & O_TEXT ?: O_BINARY); + if (flags & O_NOINHERIT) + close_on_exec (true); + uninterruptible_io (fh->uninterruptible_io ()); + cfree (fh); + CloseHandle (proc); + return 1; +out: + if (writepipe_exists) + CloseHandle (writepipe_exists); + if (guard) + CloseHandle (guard); + 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; +} + +void +fhandler_pipe::set_close_on_exec (bool val) +{ + fhandler_base::set_close_on_exec (val); + if (guard) + { + set_no_inheritance (guard, val); + ModifyHandle (guard, !val); + } + if (writepipe_exists) + set_no_inheritance (writepipe_exists, val); +} + +char * +fhandler_pipe::get_proc_fd_name (char *buf) +{ + __small_sprintf (buf, "pipe:[%d]", get_handle ()); + return buf; +} + +struct pipeargs +{ + fhandler_base *fh; + void *ptr; + size_t *len; +}; + +static DWORD WINAPI +read_pipe (void *arg) +{ + pipeargs *pi = (pipeargs *) arg; + pi->fh->fhandler_base::read (pi->ptr, *pi->len); + return 0; +} + +void __stdcall +fhandler_pipe::read (void *in_ptr, size_t& in_len) +{ + if (broken_pipe) + in_len = 0; + else + { + pipeargs pi = {dynamic_cast<fhandler_base *>(this), in_ptr, &in_len}; + cygthread *th = new cygthread (read_pipe, 0, &pi, "read_pipe"); + if (th->detach (read_state) && !in_len) + in_len = (size_t) -1; /* received a signal */ + } + ReleaseMutex (guard); +} + +int +fhandler_pipe::close () +{ + if (guard) + ForceCloseHandle (guard); + if (writepipe_exists) + CloseHandle (writepipe_exists); +#ifndef NEWVFORK + if (read_state) +#else + // FIXME is this vfork_cleanup test right? Is it responsible for some of + // the strange pipe behavior that has been reported in the cygwin mailing + // list? + if (read_state && !cygheap->fdtab.in_vfork_cleanup ()) +#endif + ForceCloseHandle (read_state); + return fhandler_base::close (); +} + +bool +fhandler_pipe::hit_eof () +{ + char buf[80]; + HANDLE ev; + if (broken_pipe) + return 1; + if (!orig_pid) + return false; + __small_sprintf (buf, pipeid_fmt, orig_pid, id); + if ((ev = OpenEvent (EVENT_ALL_ACCESS, FALSE, buf))) + CloseHandle (ev); + debug_printf ("%s %p", buf, ev); + return ev == NULL; +} + +void +fhandler_pipe::fixup_in_child () +{ + if (read_state) + create_read_state (2); +} + +void +fhandler_pipe::fixup_after_exec () +{ + if (!close_on_exec ()) + fixup_in_child (); +} + +void +fhandler_pipe::fixup_after_fork (HANDLE parent) +{ + fhandler_base::fixup_after_fork (parent); + if (guard && fork_fixup (parent, guard, "guard")) + ProtectHandle (guard); + if (writepipe_exists) + fork_fixup (parent, writepipe_exists, "writepipe_exists"); + fixup_in_child (); +} + +int +fhandler_pipe::dup (fhandler_base *child) +{ + int res = -1; + fhandler_pipe *ftp = (fhandler_pipe *) child; + ftp->guard = ftp->writepipe_exists = ftp->read_state = NULL; + + if (get_handle () && fhandler_base::dup (child)) + goto err; + + if (!guard) + /* nothing to do */; + else if (DuplicateHandle (hMainProc, guard, hMainProc, &ftp->guard, 0, true, + DUPLICATE_SAME_ACCESS)) + ProtectHandle1 (ftp->guard, guard); + else + { + debug_printf ("couldn't duplicate guard %p, %E", guard); + goto err; + } + + if (!writepipe_exists) + /* nothing to do */; + else if (!DuplicateHandle (hMainProc, writepipe_exists, hMainProc, + &ftp->writepipe_exists, 0, true, + DUPLICATE_SAME_ACCESS)) + { + debug_printf ("couldn't duplicate writepipe_exists %p, %E", writepipe_exists); + goto err; + } + + if (!read_state) + /* nothing to do */; + else if (DuplicateHandle (hMainProc, read_state, hMainProc, + &ftp->read_state, 0, false, + DUPLICATE_SAME_ACCESS)) + ProtectHandle1 (ftp->read_state, read_state); + else + { + debug_printf ("couldn't duplicate read_state %p, %E", read_state); + goto err; + } + + res = 0; + goto out; + +err: + if (ftp->guard) + ForceCloseHandle1 (ftp->guard, guard); + if (ftp->writepipe_exists) + CloseHandle (ftp->writepipe_exists); + if (ftp->read_state) + ForceCloseHandle1 (ftp->read_state, read_state); + goto leave; + +out: + ftp->id = id; + ftp->orig_pid = orig_pid; + VerifyHandle (ftp->writepipe_exists); + +leave: + debug_printf ("res %d", res); + return res; +} + +/* Create a pipe, and return handles to the read and write ends, + just like CreatePipe, but ensure that the write end permits + FILE_READ_ATTRIBUTES access, on later versions of win32 where + this is supported. This access is needed by NtQueryInformationFile, + which is used to implement select and nonblocking writes. + Note that the return value is either 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, bool fifo) +{ + /* Default to error. */ + r = w = INVALID_HANDLE_VALUE; + + /* Ensure that there is enough pipe buffer space for atomic writes. */ + if (!fifo && psize < PIPE_BUF) + psize = PIPE_BUF; + + char pipename[CYG_MAX_PATH]; + + /* Retry CreateNamedPipe as long as the pipe name is in use. + Retrying will probably never be necessary, but we want + to be as robust as possible. */ + while (1) + { + static volatile ULONG pipe_unique_id; + + __small_sprintf (pipename, "\\\\.\\pipe\\cygwin-%p-%p", myself->pid, + InterlockedIncrement ((LONG *) &pipe_unique_id)); + + debug_printf ("CreateNamedPipe: name %s, size %lu", pipename, psize); + + /* Use CreateNamedPipe instead of CreatePipe, because the latter + returns a write handle that does not permit FILE_READ_ATTRIBUTES + access, on versions of win32 earlier than WinXP SP2. + CreatePipe also stupidly creates a full duplex pipe, which is + a waste, since only a single direction is actually used. + It's important to only allow a single instance, to ensure that + the pipe was not created earlier by some other process, even if + the pid has been reused. We avoid FILE_FLAG_FIRST_PIPE_INSTANCE + because that is only available for Win2k SP2 and WinXP. */ + r = CreateNamedPipe (pipename, PIPE_ACCESS_INBOUND, + 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 && r != INVALID_HANDLE_VALUE) + { + debug_printf ("pipe read handle %p", r); + break; + } + + DWORD err = GetLastError (); + switch (err) + { + case ERROR_PIPE_BUSY: + /* The pipe is already open with compatible parameters. + Pick a new name and retry. */ + debug_printf ("pipe busy, retrying"); + break; + case ERROR_ACCESS_DENIED: + /* The pipe is already open with incompatible parameters. + Pick a new name and retry. */ + debug_printf ("pipe access denied, retrying"); + break; + default: + /* CreateNamePipe failed. Maybe we are on an older Win9x platform without + named pipes. Return an anonymous pipe as the best approximation. */ + debug_printf ("CreateNamedPipe failed, resorting to CreatePipe size %lu", + psize); + if (CreatePipe (&r, &w, sa_ptr, psize)) + { + debug_printf ("pipe read handle %p", r); + debug_printf ("pipe write handle %p", w); + return 0; + } + err = GetLastError (); + debug_printf ("CreatePipe failed, %E"); + 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, 0, 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, bool fifo) +{ + HANDLE r, w; + SECURITY_ATTRIBUTES *sa = (mode & O_NOINHERIT) ? &sec_none_nih : &sec_none; + int res = -1; + + int ret = create_selectable (sa, r, w, psize, fifo); + if (ret) + __seterrno_from_win_error (ret); + else + { + fhs[0] = (fhandler_pipe *) build_fh_dev (*piper_dev); + fhs[1] = (fhandler_pipe *) build_fh_dev (*pipew_dev); + + int binmode = mode & O_TEXT ?: O_BINARY; + fhs[0]->init (r, GENERIC_READ, binmode); + fhs[1]->init (w, GENERIC_WRITE, binmode); + if (mode & O_NOINHERIT) + { + fhs[0]->close_on_exec (true); + fhs[1]->close_on_exec (true); + } + + fhs[0]->create_read_state (2); + + res = 0; + fhs[0]->create_guard (sa); + if (wincap.has_unreliable_pipes ()) + { + char buf[80]; + int count = pipecount++; /* FIXME: Should this be InterlockedIncrement? */ + __small_sprintf (buf, pipeid_fmt, myself->pid, count); + fhs[1]->writepipe_exists = CreateEvent (sa, TRUE, FALSE, buf); + fhs[0]->orig_pid = myself->pid; + fhs[0]->id = count; + } + } + + 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; +} + +#define DEFAULT_PIPEBUFSIZE (16 * PIPE_BUF) + +extern "C" int +pipe (int filedes[2]) +{ + extern DWORD binmode; + fhandler_pipe *fhs[2]; + int res = fhandler_pipe::create (fhs, DEFAULT_PIPEBUFSIZE, + (!binmode || binmode == O_BINARY) + ? O_BINARY : O_TEXT); + if (res == 0) + { + cygheap_fdnew fdin; + cygheap_fdnew fdout (fdin, false); + 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; +} |