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* fork.cc (lock_signals): Move to sigproc.h. 

(lock_pthread): Ditto.
(hold_everything): Ditto.
(frok::parent): Call myself.prefork() just before calling CreateProcess.  Call
myself.postfork () on function exit.
* pinfo.cc (pinfo::pending_rd_proc_pipe): Define.
(pinfo::pending_wr_proc_pipe): Ditto.
(_pinfo::dup_proc_pipe): Delete.
(pinfo::wait): Move pipe creation into pinfo::prefork.  Set pipe variables from
pending_*.
(_pinfo::sync_proc_pipe): Delete.
(_pinfo::proc_pipe_owner): Ditto.
(pinfo::prefork): Define new function.
(pinfo::postfork): Ditto.
(pinfo::postexec): Ditto.
(_pinfo::alert_parent): Remove obsolete call to sync_proc_pipe.
(_pinfo::dup_proc_pipe): Delete declaration.
(_pinfo::sync_proc_pipe): Ditto.
(pinfo::pending_rd_proc_pipe): Declare.
(pinfo::pending_wr_proc_pipe): Ditto.
(pinfo::prefork): Declare new function.
(pinfo::postfork): Ditto.
(pinfo::postexec): Ditto.
(pinfo::wr_proc_pipe): Define new wrapper function.
* sigproc.h: Include "sync.h".  Move locking functions from fork to here.
* spawn.cc (child_info_spawn::worker): Delete now-unneeded requirement to
record orig_wr_proc_pipe.  Call hold_everything prior to doing anything.  Call
myself.prefork() if spawning.  Replace wr_proc_pipe synchronization with call
to myself.postexec().  Call myself.postfork() if not execing.
* sync.h: Replace #ifdef wrapper with "#pragma once".
This commit is contained in:
Christopher Faylor 2012-03-16 20:20:29 +00:00
parent d3f6480e44
commit 4aeaedf961
7 changed files with 192 additions and 169 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
winsup/cygwin/ChangeLog
View File

@ -1,3 +1,38 @@
2012-03-16 Christopher Faylor <me.cygwin2012@cgf.cx>
* fork.cc (lock_signals): Move to sigproc.h.
(lock_pthread): Ditto.
(hold_everything): Ditto.
(frok::parent): Call myself.prefork() just before calling
CreateProcess. Call myself.postfork () on function exit.
* pinfo.cc (pinfo::pending_rd_proc_pipe): Define.
(pinfo::pending_wr_proc_pipe): Ditto.
(_pinfo::dup_proc_pipe): Delete.
(pinfo::wait): Move pipe creation into pinfo::prefork. Set pipe
variables from pending_*.
(_pinfo::sync_proc_pipe): Delete.
(_pinfo::proc_pipe_owner): Ditto.
(pinfo::prefork): Define new function.
(pinfo::postfork): Ditto.
(pinfo::postexec): Ditto.
(_pinfo::alert_parent): Remove obsolete call to sync_proc_pipe.
(_pinfo::dup_proc_pipe): Delete declaration.
(_pinfo::sync_proc_pipe): Ditto.
(pinfo::pending_rd_proc_pipe): Declare.
(pinfo::pending_wr_proc_pipe): Ditto.
(pinfo::prefork): Declare new function.
(pinfo::postfork): Ditto.
(pinfo::postexec): Ditto.
(pinfo::wr_proc_pipe): Define new wrapper function.
* sigproc.h: Include "sync.h". Move locking functions from fork to
here.
* spawn.cc (child_info_spawn::worker): Delete now-unneeded requirement
to record orig_wr_proc_pipe. Call hold_everything prior to doing
anything. Call myself.prefork() if spawning. Replace wr_proc_pipe
synchronization with call to myself.postexec(). Call myself.postfork()
if not execing.
* sync.h: Replace #ifdef wrapper with "#pragma once".
2012-03-13 Corinna Vinschen <corinna@vinschen.de>
* hookapi.cc (hook_or_detect_cygwin): Change condition when to use

79
winsup/cygwin/fork.cc
View File

@ -47,83 +47,6 @@ class frok
friend int fork ();
};
class lock_signals
{
bool worked;
public:
lock_signals ()
{
worked = sig_send (NULL, __SIGHOLD) == 0;
}
operator int () const
{
return worked;
}
void dont_bother ()
{
worked = false;
}
~lock_signals ()
{
if (worked)
sig_send (NULL, __SIGNOHOLD);
}
};
class lock_pthread
{
bool bother;
public:
lock_pthread (): bother (1)
{
pthread::atforkprepare ();
}
void dont_bother ()
{
bother = false;
}
~lock_pthread ()
{
if (bother)
pthread::atforkparent ();
}
};
class hold_everything
{
public: /* DELETEME*/
bool& ischild;
/* Note the order of the locks below. It is important,
to avoid races, that the lock order be preserved.
pthread is first because it serves as a master lock
against other forks being attempted while this one is active.
signals is next to stop signal processing for the duration
of the fork.
process is last. If it is put before signals, then a deadlock
could be introduced if the process attempts to exit due to a signal. */
lock_pthread pthread;
lock_signals signals;
lock_process process;
public:
hold_everything (bool& x): ischild (x) {}
operator int () const {return signals;}
~hold_everything()
{
if (ischild)
{
pthread.dont_bother ();
process.dont_bother ();
signals.dont_bother ();
}
}
};
static void
resume_child (HANDLE forker_finished)
{
@ -407,6 +330,7 @@ frok::parent (volatile char * volatile stack_here)
while (1)
{
hchild = NULL;
myself.prefork ();
rc = CreateProcessW (myself->progname, /* image to run */
myself->progname, /* what we send in arg0 */
&sec_none_nih,
@ -592,6 +516,7 @@ frok::parent (volatile char * volatile stack_here)
/* Common cleanup code for failure cases */
cleanup:
myself.postfork ();
if (fix_impersonation)
cygheap->user.reimpersonate ();
if (locked)

111
winsup/cygwin/pinfo.cc
View File

@ -49,6 +49,9 @@ pinfo_basic myself_initial NO_COPY;
pinfo NO_COPY myself (static_cast<_pinfo *> (&myself_initial)); // Avoid myself != NULL checks
HANDLE NO_COPY pinfo::pending_rd_proc_pipe;
HANDLE NO_COPY pinfo::pending_wr_proc_pipe;
bool is_toplevel_proc;
/* Setup the pinfo structure for this process. There may already be a
@ -980,66 +983,16 @@ proc_waiter (void *arg)
return 0;
}
#ifdef DEBUGGING
#define warn_printf api_fatal
#else
#define warn_printf system_printf
#endif
HANDLE
_pinfo::dup_proc_pipe (HANDLE hProcess, const char *func)
{
DWORD flags = DUPLICATE_SAME_ACCESS;
HANDLE orig_wr_proc_pipe = wr_proc_pipe;
/* Can't set DUPLICATE_CLOSE_SOURCE for exec case because we could be
execing a non-cygwin process and we need to set the exit value before the
parent sees it. */
if (this != myself || is_toplevel_proc)
flags |= DUPLICATE_CLOSE_SOURCE;
bool res = DuplicateHandle (GetCurrentProcess (), wr_proc_pipe,
hProcess, &wr_proc_pipe, 0, FALSE, flags);
if (res)
{
wr_proc_pipe_owner = dwProcessId;
sigproc_printf ("(%s) duped wr_proc_pipe %p for pid %d(%u)", func,
wr_proc_pipe, pid, dwProcessId);
}
else
{
DWORD duperr = GetLastError ();
DWORD wfsores = WaitForSingleObject (hProcess, 0);
if (wfsores != WAIT_OBJECT_0)
{
warn_printf ("(%s) process synchronization failed for pid %u/%p, "
"wr_proc_pipe %p vs. %p: DuplicateHandle winerr %d, "
"WFSO returned %u, %E",
func, pid, hProcess, wr_proc_pipe, orig_wr_proc_pipe, duperr,
wfsores);
}
wr_proc_pipe = orig_wr_proc_pipe;
}
return orig_wr_proc_pipe;
}
/* function to set up the process pipe and kick off proc_waiter */
bool
pinfo::wait ()
{
/* If rd_proc_pipe != NULL we're in an execed process which already has
grabbed the read end of the pipe from the previous cygwin process running
with this pid. */
if (!rd_proc_pipe)
{
/* FIXME: execed processes should be able to wait for pids that were started
by the process which execed them. */
if (!CreatePipe (&rd_proc_pipe, &((*this)->wr_proc_pipe), &sec_none_nih, 16))
{
system_printf ("Couldn't create pipe tracker for pid %d, %E",
(*this)->pid);
return false;
}
rd_proc_pipe = pending_rd_proc_pipe;
pending_rd_proc_pipe = NULL;
(*this)->dup_proc_pipe (hProcess, "pinfo::wait");
}
wr_proc_pipe () = pending_wr_proc_pipe;
ForceCloseHandle1 (pending_wr_proc_pipe, wr_proc_pipe);
pending_wr_proc_pipe = NULL;
preserve (); /* Preserve the shared memory associated with the pinfo */
@ -1059,11 +1012,48 @@ pinfo::wait ()
}
void
_pinfo::sync_proc_pipe ()
pinfo::prefork (bool detached)
{
if (wr_proc_pipe && wr_proc_pipe != INVALID_HANDLE_VALUE)
while (wr_proc_pipe_owner != GetCurrentProcessId ())
yield ();
if (wr_proc_pipe () && wr_proc_pipe () != INVALID_HANDLE_VALUE
&& !SetHandleInformation (wr_proc_pipe (), HANDLE_FLAG_INHERIT, 0))
api_fatal ("couldn't set process pipe(%p) inherit state, %E", wr_proc_pipe ());
/* If rd_proc_pipe != NULL we're in an execed process which already has
grabbed the read end of the pipe from the previous cygwin process running
with this pid. */
if (!detached)
{
if (!CreatePipe (&pending_rd_proc_pipe, &pending_wr_proc_pipe,
&sec_none_nih, 16))
api_fatal ("Couldn't create pipe tracker for pid %d, %E", (*this)->pid);
if (!SetHandleInformation (pending_wr_proc_pipe, HANDLE_FLAG_INHERIT,
HANDLE_FLAG_INHERIT))
api_fatal ("prefork: couldn't set process pipe(%p) inherit state, %E",
pending_wr_proc_pipe);
ProtectHandle1 (pending_rd_proc_pipe, rd_proc_pipe);
ProtectHandle1 (pending_wr_proc_pipe, wr_proc_pipe);
}
}
void
pinfo::postfork ()
{
if (wr_proc_pipe () && wr_proc_pipe () != INVALID_HANDLE_VALUE
&& !SetHandleInformation (wr_proc_pipe (), HANDLE_FLAG_INHERIT,
HANDLE_FLAG_INHERIT))
api_fatal ("postfork: couldn't set process pipe(%p) inherit state, %E", wr_proc_pipe ());
if (pending_rd_proc_pipe)
ForceCloseHandle1 (pending_rd_proc_pipe, rd_proc_pipe);
if (pending_wr_proc_pipe)
ForceCloseHandle1 (pending_wr_proc_pipe, wr_proc_pipe);
}
void
pinfo::postexec ()
{
if (wr_proc_pipe () && wr_proc_pipe () != INVALID_HANDLE_VALUE
&& !ForceCloseHandle (wr_proc_pipe ()))
api_fatal ("postexec: couldn't close wr_proc_pipe(%p), %E", wr_proc_pipe ());
}
/* function to send a "signal" to the parent when something interesting happens
@ -1078,11 +1068,10 @@ _pinfo::alert_parent (char sig)
FIXME: Is there a race here if we run this while another thread is attempting
to exec()? */
if (wr_proc_pipe == INVALID_HANDLE_VALUE || !myself->wr_proc_pipe || have_execed)
if (wr_proc_pipe == INVALID_HANDLE_VALUE || !myself.wr_proc_pipe () || have_execed)
/* no parent */;
else
{
sync_proc_pipe ();
if (WriteFile (wr_proc_pipe, &sig, 1, &nb, NULL))
/* all is well */;
else if (GetLastError () != ERROR_BROKEN_PIPE)

10
winsup/cygwin/pinfo.h
View File

@ -111,8 +111,6 @@ public:
char *cwd (size_t &);
char *cmdline (size_t &);
bool set_ctty (class fhandler_termios *, int);
HANDLE dup_proc_pipe (HANDLE, const char *) __attribute__ ((regparm(3)));
void sync_proc_pipe ();
bool alert_parent (char);
int __stdcall kill (siginfo_t&) __attribute__ ((regparm (2)));
bool __stdcall exists () __attribute__ ((regparm (1)));
@ -124,7 +122,6 @@ public:
DWORD exec_dwProcessId;
public:
HANDLE wr_proc_pipe;
DWORD wr_proc_pipe_owner;
friend class pinfo_minimal;
};
@ -150,6 +147,8 @@ class pinfo: public pinfo_minimal
{
bool destroy;
_pinfo *procinfo;
static HANDLE pending_rd_proc_pipe;
static HANDLE pending_wr_proc_pipe;
public:
bool waiter_ready;
class cygthread *wait_thread;
@ -205,10 +204,15 @@ public:
return res;
}
#endif
void prefork (bool = false);
void postfork ();
void postexec ();
HANDLE shared_handle () {return h;}
void set_acl ();
friend class _pinfo;
friend class winpids;
private:
HANDLE& wr_proc_pipe() {return procinfo->wr_proc_pipe;}
};
#define ISSTATE(p, f) (!!((p)->process_state & f))

78
winsup/cygwin/sigproc.h
View File

@ -11,6 +11,7 @@ details. */
#pragma once
#include <signal.h>
#include "sync.h"
#ifdef NSIG
enum
@ -121,4 +122,81 @@ extern char myself_nowait_dummy[];
extern struct sigaction *global_sigs;
class lock_signals
{
bool worked;
public:
lock_signals ()
{
worked = sig_send (NULL, __SIGHOLD) == 0;
}
operator int () const
{
return worked;
}
void dont_bother ()
{
worked = false;
}
~lock_signals ()
{
if (worked)
sig_send (NULL, __SIGNOHOLD);
}
};
class lock_pthread
{
bool bother;
public:
lock_pthread (): bother (1)
{
pthread::atforkprepare ();
}
void dont_bother ()
{
bother = false;
}
~lock_pthread ()
{
if (bother)
pthread::atforkparent ();
}
};
class hold_everything
{
public: /* DELETEME*/
bool ischild;
/* Note the order of the locks below. It is important,
to avoid races, that the lock order be preserved.
pthread is first because it serves as a master lock
against other forks being attempted while this one is active.
signals is next to stop signal processing for the duration
of the fork.
process is last. If it is put before signals, then a deadlock
could be introduced if the process attempts to exit due to a signal. */
lock_pthread pthread;
lock_signals signals;
lock_process process;
public:
hold_everything (bool x = false): ischild (x) {}
operator int () const {return signals;}
~hold_everything()
{
if (ischild)
{
pthread.dont_bother ();
process.dont_bother ();
signals.dont_bother ();
}
}
};
#define myself_nowait ((_pinfo *) myself_nowait_dummy)

39
winsup/cygwin/spawn.cc
View File

@ -308,6 +308,7 @@ child_info_spawn::worker (const char *prog_arg, const char *const *argv,
return -1;
}
hold_everything for_now;
/* FIXME: There is a small race here and FIXME: not thread safe! */
pthread_cleanup cleanup;
@ -335,7 +336,6 @@ child_info_spawn::worker (const char *prog_arg, const char *const *argv,
bool null_app_name = false;
STARTUPINFOW si = {};
int looped = 0;
HANDLE orig_wr_proc_pipe = NULL;
myfault efault;
if (efault.faulted ())
@ -349,10 +349,13 @@ child_info_spawn::worker (const char *prog_arg, const char *const *argv,
}
child_info_types chtype;
if (mode != _P_OVERLAY)
chtype = _CH_SPAWN;
else
if (mode == _P_OVERLAY)
chtype = _CH_EXEC;
else
{
chtype = _CH_SPAWN;
myself.prefork ();
}
moreinfo = cygheap_exec_info::alloc ();
@ -770,23 +773,16 @@ loop:
sigproc_printf ("new process name %W", myself->progname);
/* If wr_proc_pipe doesn't exist then this process was not started by a cygwin
process. So, we need to wait around until the process we've just "execed"
dies. Use our own wait facility to wait for our own pid to exit (there
is some minor special case code in proc_waiter and friends to accommodate
this).
dies. Use our own wait facility below to wait for our own pid to exit
(there is some minor special case code in proc_waiter and friends to
accommodate this).
If wr_proc_pipe exists, then it should be duplicated to the child.
If wr_proc_pipe exists, then it will be inherited by the child.
If the child has exited already, that's ok. The parent will pick up
on this fact when we exit. dup_proc_pipe will close our end of the pipe.
Note that wr_proc_pipe may also be == INVALID_HANDLE_VALUE. That will make
dup_proc_pipe essentially a no-op. */
on this fact when we exit. myself.postexec () will close our end of
the pipe. */
if (!newargv.win16_exe && myself->wr_proc_pipe)
{
if (!looped)
myself->sync_proc_pipe (); /* Make sure that we own wr_proc_pipe
just in case we've been previously
execed. */
orig_wr_proc_pipe = myself->dup_proc_pipe (pi.hProcess, "child_info_spawn::worker");
}
myself.postexec ();
pid = myself->pid;
if (!iscygwin ())
close_all_files ();
@ -851,11 +847,6 @@ loop:
myself.hProcess = pi.hProcess;
if (!synced)
{
if (orig_wr_proc_pipe)
{
myself->wr_proc_pipe_owner = GetCurrentProcessId ();
myself->wr_proc_pipe = orig_wr_proc_pipe;
}
if (!proc_retry (pi.hProcess))
{
looped++;
@ -896,6 +887,8 @@ loop:
}
out:
if (mode != _P_OVERLAY)
myself.postfork ();
this->cleanup ();
if (envblock)
free (envblock);

9
winsup/cygwin/sync.h
View File

@ -1,6 +1,7 @@
/* sync.h: Header file for cygwin synchronization primitives.
Copyright 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 Red Hat, Inc.
Copyright 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2011, 2012
Red Hat, Inc.
This file is part of Cygwin.
@ -8,8 +9,8 @@ This software is a copyrighted work licensed under the terms of the
Cygwin license. Please consult the file "CYGWIN_LICENSE" for
details. */
#ifndef _SYNC_H
#define _SYNC_H
#pragma once
/* FIXME: Note that currently this class cannot be allocated via `new' since
there are issues with malloc and fork. */
class muto
@ -62,5 +63,3 @@ public:
friend class dtable;
friend class fhandler_fifo;
};
#endif /*_SYNC_H*/