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Implement correct RLIMIT_STACK handling

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* miscfuncs.cc (struct pthread_wrapper_arg): Add member guardsize.
        (pthread_wrapper): Set thread stack guarantee according to guardsize.
        Tweak assembler code so that $rax/$eax is not required by GCC to
        prepare the wrapper_arg value.
        (CygwinCreateThread): Fix deadzone handling.  Drop setting a "POSIX"
        guardpage (aka page w/ PAGE_NOACCESS).  Always use Windows guard
        pages instead.  On post-XP systems (providing SetThreadStackGuarantee)
        always set up stack Windows like with reserved/commited areas and
        movable guard pages.  Only on XP set up stack fully commited if the
        guardpage size is not the default system guardpage size.
        Fill out pthread_wrapper_arg::guardsize.  Improve comments.
        * resource.cc: Implement RSTACK_LIMIT Linux-like.
        (DEFAULT_STACKSIZE): New macro.
        (DEFAULT_STACKGUARD): Ditto.
        (rlimit_stack_guard): New muto.
        (rlimit_stack): New global variable holding current RSTACK_LIMIT values.
        (__set_rlimit_stack): Set rlimit_stack under lock.
        (__get_rlimit_stack): Initialize rlimit_stack from executable header
        and return rlimit_stack values under lock.
        (get_rlimit_stack): Filtering function to return useful default
        stacksize from rlimit_stack.rlim_cur value.
        (getrlimit): Call __get_rlimit_stack in RLIMIT_STACK case.
        (setrlimit): Call __set_rlimit_stack in RLIMIT_STACK case.
        * thread.cc (pthread::create): Fetch default stacksize calling
        get_rlimit_stack.
        (pthread_attr::pthread_attr): Fetch default guardsize calling
        wincap.def_guard_page_size.
        (pthread_attr_getstacksize): Fetch default stacksize calling
        get_rlimit_stack.
        * thread.h (PTHREAD_DEFAULT_STACKSIZE): Remove.
        (PTHREAD_DEFAULT_GUARDSIZE): Remove.
        (get_rlimit_stack): Declare.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
This commit is contained in:
Corinna Vinschen
2015-07-05 15:51:37 +02:00
parent e426213a88
commit a54bc198b1
7 changed files with 172 additions and 71 deletions
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85
winsup/cygwin/resource.cc
View File

@ -111,6 +111,61 @@ getrusage (int intwho, struct rusage *rusage_in)
return res;
}
/* Default stacksize in case RLIMIT_STACK is RLIM_INFINITY is 2 Megs with
system-dependent number of guard pages. The pthread stacksize does not
include the guardpage size, so we have to subtract the default guardpage
size. Additionally the Windows stack handling disallows to commit the
last page, so we subtract it, too. */
#define DEFAULT_STACKSIZE (2 * 1024 * 1024)
#define DEFAULT_STACKGUARD (wincap.def_guard_page_size() + wincap.page_size ())
muto NO_COPY rlimit_stack_guard;
static struct rlimit rlimit_stack = { 0, RLIM_INFINITY };
static void
__set_rlimit_stack (const struct rlimit *rlp)
{
rlimit_stack_guard.init ("rlimit_stack_guard")->acquire ();
rlimit_stack = *rlp;
rlimit_stack_guard.release ();
}
static void
__get_rlimit_stack (struct rlimit *rlp)
{
rlimit_stack_guard.init ("rlimit_stack_guard")->acquire ();
if (!rlimit_stack.rlim_cur)
{
/* Fetch the default stacksize from the executable header... */
PIMAGE_DOS_HEADER dosheader;
PIMAGE_NT_HEADERS ntheader;
dosheader = (PIMAGE_DOS_HEADER) GetModuleHandle (NULL);
ntheader = (PIMAGE_NT_HEADERS) ((PBYTE) dosheader + dosheader->e_lfanew);
rlimit_stack.rlim_cur = ntheader->OptionalHeader.SizeOfStackReserve;
/* ...and subtract the guardpages. */
rlimit_stack.rlim_cur -= DEFAULT_STACKGUARD;
}
*rlp = rlimit_stack;
rlimit_stack_guard.release ();
}
size_t
get_rlimit_stack (void)
{
struct rlimit rl;
__get_rlimit_stack (&rl);
/* RLIM_INFINITY doesn't make much sense. As in glibc, use an
"architecture-specific default". */
if (rl.rlim_cur == RLIM_INFINITY)
rl.rlim_cur = DEFAULT_STACKSIZE - DEFAULT_STACKGUARD;
/* Always return at least minimum stacksize. */
else if (rl.rlim_cur < PTHREAD_STACK_MIN)
rl.rlim_cur = PTHREAD_STACK_MIN;
return (size_t) rl.rlim_cur;
}
extern "C" int
getrlimit (int resource, struct rlimit *rlp)
{
@ -127,32 +182,7 @@ getrlimit (int resource, struct rlimit *rlp)
case RLIMIT_AS:
break;
case RLIMIT_STACK:
PTEB teb;
/* 2015-06-26: Originally rlim_cur returned the size of the still
available stack area on the current stack, rlim_max the total size
of the current stack. Two problems:
- Per POSIX, RLIMIT_STACK returns "the maximum size of the initial
thread's stack, in bytes. The implementation does not
automatically grow the stack beyond this limit".
- With the implementation of sigaltstack, the current stack is not
necessarily the "initial thread's stack" anymore. Rather, when
called from a signal handler running on the alternate stack,
RLIMIT_STACK should return the size of the original stack.
rlim_cur is now the size of the stack. For system-provided stacks
it's the size between DeallocationStack and StackBase. For
application-provided stacks (via pthread_attr_setstack),
DeallocationStack is NULL, but StackLimit points to the bottom
of the stack.
rlim_max is set to RLIM_INFINITY since there's no hard limit
for stack sizes on Windows. */
teb = NtCurrentTeb ();
rlp->rlim_cur = (rlim_t) teb->Tib.StackBase
- (rlim_t) (teb->DeallocationStack
?: teb->Tib.StackLimit);
__get_rlimit_stack (rlp);
break;
case RLIMIT_NOFILE:
rlp->rlim_cur = getdtablesize ();
@ -206,6 +236,9 @@ setrlimit (int resource, const struct rlimit *rlp)
if (rlp->rlim_cur != RLIM_INFINITY)
return setdtablesize (rlp->rlim_cur);
break;
case RLIMIT_STACK:
__set_rlimit_stack (rlp);
break;
default:
set_errno (EINVAL);
__leave;