* cygheap.cc (init_cygheap::find_tls): Add comment.

* cygtls.cc (well_known_dlls): Rephrase comment.
	(bloda_detect): New function.
	(_cygtls::call2): Call init_thread and bloda_detect for non-pthread
	threads only.
	(_cygtls::remove): Move remove_tls and remove_wq calls up to run first.
	* miscfuncs.cc (struct pthread_wrapper_arg): Rename from struct
	thread_wrapper_arg.
	(pthread_wrapper): Rename from thread_wrapper and drop "static".  Fix
	comment.  Drop call to _cygtls::remove.  Call api_fatal rather than
	ExitThread.  Explain why.
	* miscfuncs.h (pthread_wrapper): Declare pthread_wrapper.
	* thread.cc (pthread::exit): Add a FIXME comment.  Call _cygtls::remove
	before calling ExitThread.
This commit is contained in:
Corinna Vinschen 2014-11-28 12:10:12 +00:00
parent b3281dd194
commit 9d2eff6684
6 changed files with 88 additions and 57 deletions

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@ -1,3 +1,20 @@
2014-11-28 Corinna Vinschen <corinna@vinschen.de>
* cygheap.cc (init_cygheap::find_tls): Add comment.
* cygtls.cc (well_known_dlls): Rephrase comment.
(bloda_detect): New function.
(_cygtls::call2): Call init_thread and bloda_detect for non-pthread
threads only.
(_cygtls::remove): Move remove_tls and remove_wq calls up to run first.
* miscfuncs.cc (struct pthread_wrapper_arg): Rename from struct
thread_wrapper_arg.
(pthread_wrapper): Rename from thread_wrapper and drop "static". Fix
comment. Drop call to _cygtls::remove. Call api_fatal rather than
ExitThread. Explain why.
* miscfuncs.h (pthread_wrapper): Declare pthread_wrapper.
* thread.cc (pthread::exit): Add a FIXME comment. Call _cygtls::remove
before calling ExitThread.
2014-11-27 Corinna Vinschen <corinna@vinschen.de>
* mount.cc (mount_info::init): Take bool argument and allow to

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@ -673,6 +673,7 @@ init_cygheap::find_tls (int sig, bool& issig_wait)
{
__try
{
/* Only pthreads have tid set to non-0. */
if (!threadlist[ix]->tid)
continue;
else if (sigismember (&(threadlist[ix]->sigwait_mask), sig))

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@ -1,7 +1,7 @@
/* cygtls.cc
Copyright 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012,
2013 Red Hat, Inc.
2013, 2014 Red Hat, Inc.
This software is a copyrighted work licensed under the terms of the
Cygwin license. Please consult the file "CYGWIN_LICENSE" for
@ -38,10 +38,9 @@ dll_cmp (const void *a, const void *b)
/* Keep sorted!
This is a list of well-known core system DLLs which contain code
whiuch is started in its own thread by the system. Kernel32.dll,
for instance, contains the thread called on every Ctrl-C keypress
in a console window. The DLLs in this list are not recognized as
BLODAs. */
started in its own thread by the system. Kernel32.dll, for instance,
contains the thread called on every Ctrl-C keypress in a console window.
The DLLs in this list are not recognized as BLODAs. */
const wchar_t *well_known_dlls[] =
{
L"advapi32.dll",
@ -55,25 +54,21 @@ const wchar_t *well_known_dlls[] =
L"ws2_32.dll",
};
void
_cygtls::call2 (DWORD (*func) (void *, void *), void *arg, void *buf)
/* Optional BLODA detection. The idea is that the function address is supposed
to be within Cygwin itself. This is also true for pthreads, since pthreads
are always calling pthread::thread_init_wrapper() in thread.cc. Therefore,
every function call to a function outside of the Cygwin DLL is potentially
a thread injected into the Cygwin process by some BLODA.
But that's too simple. Assuming the application itself calls CreateThread,
then this is a bad idea, but not really invalid. So we shouldn't print a
BLODA message if the address is within the loaded image of the application.
Also, ntdll.dll starts threads into the application which */
static void
bloda_detect (DWORD (*func) (void *, void *))
{
init_thread (buf, func);
/* Optional BLODA detection. The idea is that the function address is
supposed to be within Cygwin itself. This is also true for pthreads,
since pthreads are always calling thread_wrapper in miscfuncs.cc.
Therefore, every function call to a function outside of the Cygwin DLL
is potentially a thread injected into the Cygwin process by some BLODA.
But that's a bit too simple. Assuming the application itself calls
CreateThread, then this is a bad idea, but not really invalid. So we
shouldn't print a BLODA message if the address is within the loaded
image of the application. Also, ntdll.dll starts threads into the
application which */
if (detect_bloda)
{
PIMAGE_DOS_HEADER img_start = (PIMAGE_DOS_HEADER) GetModuleHandle (NULL);
PIMAGE_DOS_HEADER img_start = (PIMAGE_DOS_HEADER)
GetModuleHandle (NULL);
PIMAGE_NT_HEADERS32 ntheader = (PIMAGE_NT_HEADERS32)
((PBYTE) img_start + img_start->e_lfanew);
void *img_end = (void *) ((PBYTE) img_start
@ -86,15 +81,31 @@ _cygtls::call2 (DWORD (*func) (void *, void *), void *arg, void *buf)
wchar_t modname[PATH_MAX];
VirtualQuery ((PVOID) func, &mbi, sizeof mbi);
GetModuleFileNameW ((HMODULE) mbi.AllocationBase, modname, PATH_MAX);
GetModuleFileNameW ((HMODULE) mbi.AllocationBase, modname,
PATH_MAX);
/* Fetch basename and check against list of above system DLLs. */
const wchar_t *modbasename = wcsrchr (modname, L'\\') + 1;
if (!bsearch (modbasename, well_known_dlls,
sizeof well_known_dlls / sizeof well_known_dlls[0],
sizeof well_known_dlls[0], dll_cmp))
small_printf ("\n\nPotential BLODA detected! Thread function "
"called outside of Cygwin DLL:\n %W\n\n", modname);
"called outside of Cygwin DLL:\n %W\n\n",
modname);
}
}
void
_cygtls::call2 (DWORD (*func) (void *, void *), void *arg, void *buf)
{
/* If func is pthread_wrapper, the final stack hasn't been set up yet.
This only happens in pthread_wrapper itself. Thus it doesn't make
sense to call init_thread or perform BLODA detection. pthread_wrapper
eventually calls init_thread by itself. */
if ((void *) func != (void *) pthread_wrapper)
{
init_thread (buf, func);
if (detect_bloda)
bloda_detect (func);
}
DWORD res = func (arg, buf);
@ -169,6 +180,9 @@ _cygtls::remove (DWORD wait)
debug_printf ("wait %u", wait);
cygheap->remove_tls (this, INFINITE);
remove_wq (wait);
/* FIXME: Need some sort of atthreadexit function to allow things like
select to control this themselves. */
@ -197,8 +211,6 @@ _cygtls::remove (DWORD wait)
/* Close timer handle. */
if (locals.cw_timer)
NtClose (locals.cw_timer);
cygheap->remove_tls (this, wait);
remove_wq (wait);
}
#ifdef __x86_64__

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@ -540,7 +540,7 @@ __import_address (void *imp)
parameters we don't use and instead to add parameters we need to make
the function pthreads compatible. */
struct thread_wrapper_arg
struct pthread_wrapper_arg
{
LPTHREAD_START_ROUTINE func;
PVOID arg;
@ -549,23 +549,20 @@ struct thread_wrapper_arg
PBYTE stacklimit;
};
static DWORD WINAPI
thread_wrapper (PVOID arg)
DWORD WINAPI
pthread_wrapper (PVOID arg)
{
/* Just plain paranoia. */
if (!arg)
return ERROR_INVALID_PARAMETER;
/* The process is now threaded. Note the fact for later usage. */
/* The process is now threaded. Note for later usage by arc4random. */
__isthreaded = 1;
/* Fetch thread wrapper info and free from cygheap. */
thread_wrapper_arg wrapper_arg = *(thread_wrapper_arg *) arg;
pthread_wrapper_arg wrapper_arg = *(pthread_wrapper_arg *) arg;
cfree (arg);
/* Remove _cygtls from this stack since it won't be used anymore. */
_my_tls.remove (0);
/* Set stack values in TEB */
PTEB teb = NtCurrentTeb ();
teb->Tib.StackBase = wrapper_arg.stackbase;
@ -676,8 +673,9 @@ thread_wrapper (PVOID arg)
: : [WRAPPER_ARG] "r" (&wrapper_arg),
[CYGTLS] "i" (CYGTLS_PADSIZE));
#endif
/* Never return from here. */
ExitThread (0);
/* pthread::thread_init_wrapper calls pthread::exit, which
in turn calls ExitThread, so we should never arrive here. */
api_fatal ("Dumb thinko in pthread handling. Whip the developer.");
}
#ifdef __x86_64__
@ -751,10 +749,10 @@ CygwinCreateThread (LPTHREAD_START_ROUTINE thread_func, PVOID thread_arg,
PVOID real_stackaddr = NULL;
ULONG real_stacksize = 0;
ULONG real_guardsize = 0;
thread_wrapper_arg *wrapper_arg;
pthread_wrapper_arg *wrapper_arg;
HANDLE thread = NULL;
wrapper_arg = (thread_wrapper_arg *) ccalloc (HEAP_STR, 1,
wrapper_arg = (pthread_wrapper_arg *) ccalloc (HEAP_STR, 1,
sizeof *wrapper_arg);
if (!wrapper_arg)
{
@ -846,7 +844,7 @@ CygwinCreateThread (LPTHREAD_START_ROUTINE thread_func, PVOID thread_arg,
reserve a 256K stack, not 64K, otherwise the thread creation might
crash the process due to a stack overflow. */
thread = CreateThread (&sec_none_nih, 4 * PTHREAD_STACK_MIN,
thread_wrapper, wrapper_arg,
pthread_wrapper, wrapper_arg,
creation_flags | STACK_SIZE_PARAM_IS_A_RESERVATION,
thread_id);

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@ -66,6 +66,7 @@ ssize_t __reg3 check_iovec (const struct iovec *, int, bool);
#define check_iovec_for_read(a, b) check_iovec ((a), (b), false)
#define check_iovec_for_write(a, b) check_iovec ((a), (b), true)
extern "C" DWORD WINAPI pthread_wrapper (PVOID arg);
extern "C" HANDLE WINAPI CygwinCreateThread (LPTHREAD_START_ROUTINE thread_func,
PVOID thread_arg, PVOID stackaddr,
ULONG stacksize, ULONG guardsize,

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@ -543,11 +543,13 @@ pthread::exit (void *value_ptr)
{
if (is_main_tls)
{
/* FIXME: Needs locking. */
_cygtls *dummy = (_cygtls *) malloc (sizeof (_cygtls));
*dummy = *_main_tls;
_main_tls = dummy;
_main_tls->initialized = false;
_main_tls->initialized = 0;
}
cygtls->remove (INFINITE);
ExitThread (0);
}
}