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Rename parent stack members in child_info struct to align with OS names

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* child_info.h (CURR_CHILD_INFO_MAGIC): Align to below change.
        (class child_info_fork): Rename stacktop to stacklimit.  Rename
        stackbottom to stackbase.  Accommodate name change throughout Cygwin.
        Rephrase comments to be clearer.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
This commit is contained in:
Corinna Vinschen 2015-12-02 12:31:40 +01:00
parent 7b0c063f12
commit 8974e06da3
4 changed files with 36 additions and 28 deletions
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7
winsup/cygwin/ChangeLog
View File

@ -1,3 +1,10 @@
2015-12-02 Corinna Vinschen <corinna@vinschen.de>
* child_info.h (CURR_CHILD_INFO_MAGIC): Align to below change.
(class child_info_fork): Rename stacktop to stacklimit. Rename
stackbottom to stackbase. Accommodate name change throughout Cygwin.
Rephrase comments to be clearer.
2015-12-02 Corinna Vinschen <corinna@vinschen.de> 2015-12-02 Corinna Vinschen <corinna@vinschen.de>
* cygtls.h (_tlsbase): Remove. Replace throughout with * cygtls.h (_tlsbase): Remove. Replace throughout with

9
winsup/cygwin/child_info.h
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@ -39,7 +39,7 @@ enum child_status
#define EXEC_MAGIC_SIZE sizeof(child_info) #define EXEC_MAGIC_SIZE sizeof(child_info)
/* Change this value if you get a message indicating that it is out-of-sync. */ /* Change this value if you get a message indicating that it is out-of-sync. */
#define CURR_CHILD_INFO_MAGIC 0x4a91a908U #define CURR_CHILD_INFO_MAGIC 0xc96f5e9U
#define NPROCS 256 #define NPROCS 256
@ -103,9 +103,10 @@ class child_info_fork: public child_info
public: public:
HANDLE forker_finished;// for synchronization with child HANDLE forker_finished;// for synchronization with child
jmp_buf jmp; // where child will jump to jmp_buf jmp; // where child will jump to
void *stackaddr; // address of parent stack void *stackaddr; // DeallocationStack or user-provided allocation address
void *stacktop; // location of top of parent stack // of parent thread
void *stackbottom; // location of bottom of parent stack void *stacklimit; // StackLimit of parent thread
void *stackbase; // StackBase of parent thread
size_t guardsize; // size of POSIX guard region or (size_t) -1 if size_t guardsize; // size of POSIX guard region or (size_t) -1 if
// user stack // user stack
char filler[4]; char filler[4];

36
winsup/cygwin/dcrt0.cc
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@ -412,15 +412,15 @@ child_info_fork::alloc_stack ()
/* Make sure not to try a hard allocation if we have been forked off from /* Make sure not to try a hard allocation if we have been forked off from
the main thread of a Cygwin process which has been started from a 64 bit the main thread of a Cygwin process which has been started from a 64 bit
parent. In that case the StackBase of the forked child is not the same parent. In that case the StackBase of the forked child is not the same
as the StackBase of the parent (== stackbottom), but only because the as the StackBase of the parent (== this.stackbase), but only because the
stack of the parent has been slightly rearranged. See comment in stack of the parent has been slightly rearranged. See comment in
wow64_revert_to_original_stack for details. We check here if the wow64_revert_to_original_stack for details. We check here if the
parent stack fits into the child stack. */ parent stack fits into the child stack. */
PTEB teb = NtCurrentTeb (); PTEB teb = NtCurrentTeb ();
if (teb->Tib.StackBase != stackbottom if (teb->Tib.StackBase != stackbase
&& (!wincap.is_wow64 () && (!wincap.is_wow64 ()
|| stacktop < teb->DeallocationStack || stacklimit < teb->DeallocationStack
|| stackbottom > teb->Tib.StackBase)) || stackbase > teb->Tib.StackBase))
{ {
void *stack_ptr; void *stack_ptr;
size_t stacksize; size_t stacksize;
@ -430,21 +430,21 @@ child_info_fork::alloc_stack ()
if (guardsize == (size_t) -1) if (guardsize == (size_t) -1)
return; return;
/* Reserve entire stack. */ /* Reserve entire stack. */
stacksize = (PBYTE) stackbottom - (PBYTE) stackaddr; stacksize = (PBYTE) stackbase - (PBYTE) stackaddr;
if (!VirtualAlloc (stackaddr, stacksize, MEM_RESERVE, PAGE_NOACCESS)) if (!VirtualAlloc (stackaddr, stacksize, MEM_RESERVE, PAGE_NOACCESS))
{ {
api_fatal ("fork: can't reserve memory for parent stack " api_fatal ("fork: can't reserve memory for parent stack "
"%p - %p, (child has %p - %p), %E", "%p - %p, (child has %p - %p), %E",
stackaddr, stackbottom, teb->DeallocationStack, stackaddr, stackbase, teb->DeallocationStack,
teb->Tib.StackBase); teb->Tib.StackBase);
} }
/* Commit the area commited in parent. */ /* Commit the area commited in parent. */
stacksize = (PBYTE) stackbottom - (PBYTE) stacktop; stacksize = (PBYTE) stackbase - (PBYTE) stacklimit;
stack_ptr = VirtualAlloc (stacktop, stacksize, MEM_COMMIT, stack_ptr = VirtualAlloc (stacklimit, stacksize, MEM_COMMIT,
PAGE_READWRITE); PAGE_READWRITE);
if (!stack_ptr) if (!stack_ptr)
api_fatal ("can't commit memory for stack %p(%ly), %E", api_fatal ("can't commit memory for stack %p(%ly), %E",
stacktop, stacksize); stacklimit, stacksize);
/* Set up guardpages. */ /* Set up guardpages. */
ULONG real_guardsize = guardsize ULONG real_guardsize = guardsize
? roundup2 (guardsize, wincap.page_size ()) ? roundup2 (guardsize, wincap.page_size ())
@ -472,26 +472,26 @@ child_info_fork::alloc_stack ()
/* Fork has been called from main thread. Simply commit the region /* Fork has been called from main thread. Simply commit the region
of the stack commited in the parent but not yet commited in the of the stack commited in the parent but not yet commited in the
child and create new guardpages. */ child and create new guardpages. */
if (NtCurrentTeb()->Tib.StackLimit > stacktop) if (NtCurrentTeb()->Tib.StackLimit > stacklimit)
{ {
SIZE_T commitsize = (PBYTE) NtCurrentTeb()->Tib.StackLimit SIZE_T commitsize = (PBYTE) NtCurrentTeb()->Tib.StackLimit
- (PBYTE) stacktop; - (PBYTE) stacklimit;
if (!VirtualAlloc (stacktop, commitsize, MEM_COMMIT, PAGE_READWRITE)) if (!VirtualAlloc (stacklimit, commitsize, MEM_COMMIT, PAGE_READWRITE))
api_fatal ("can't commit child memory for stack %p(%ly), %E", api_fatal ("can't commit child memory for stack %p(%ly), %E",
stacktop, commitsize); stacklimit, commitsize);
PVOID guardpage = (PBYTE) stacktop - wincap.def_guard_page_size (); PVOID guardpage = (PBYTE) stacklimit - wincap.def_guard_page_size ();
if (!VirtualAlloc (guardpage, wincap.def_guard_page_size (), if (!VirtualAlloc (guardpage, wincap.def_guard_page_size (),
MEM_COMMIT, PAGE_READWRITE | PAGE_GUARD)) MEM_COMMIT, PAGE_READWRITE | PAGE_GUARD))
api_fatal ("fork: couldn't allocate new stack guard page %p, %E", api_fatal ("fork: couldn't allocate new stack guard page %p, %E",
guardpage); guardpage);
NtCurrentTeb()->Tib.StackLimit = stacktop; NtCurrentTeb()->Tib.StackLimit = stacklimit;
} }
stackaddr = 0; stackaddr = 0;
/* This only affects forked children of a process started from a native /* This only affects forked children of a process started from a native
64 bit process, but it doesn't hurt to do it unconditionally. Fix 64 bit process, but it doesn't hurt to do it unconditionally. Fix
StackBase in the child to be the same as in the parent, so that the StackBase in the child to be the same as in the parent, so that the
computation of _my_tls is correct. */ computation of _my_tls is correct. */
teb->Tib.StackBase = (PVOID) stackbottom; teb->Tib.StackBase = (PVOID) stackbase;
} }
} }
@ -920,8 +920,8 @@ dll_crt0_1 (void *)
this step. */ this step. */
if (fork_info->stackaddr) if (fork_info->stackaddr)
{ {
NtCurrentTeb()->Tib.StackBase = (PVOID) fork_info->stackbottom; NtCurrentTeb()->Tib.StackBase = (PVOID) fork_info->stackbase;
NtCurrentTeb()->Tib.StackLimit = (PVOID) fork_info->stacktop; NtCurrentTeb()->Tib.StackLimit = (PVOID) fork_info->stacklimit;
} }
/* Not resetting _my_tls.incyg here because presumably fork will overwrite /* Not resetting _my_tls.incyg here because presumably fork will overwrite

12
winsup/cygwin/fork.cc
View File

@ -307,7 +307,7 @@ frok::parent (volatile char * volatile stack_here)
ch.forker_finished = forker_finished; ch.forker_finished = forker_finished;
ch.stackbottom = NtCurrentTeb()->Tib.StackBase; ch.stackbase = NtCurrentTeb()->Tib.StackBase;
ch.stackaddr = NtCurrentTeb ()->DeallocationStack; ch.stackaddr = NtCurrentTeb ()->DeallocationStack;
if (!ch.stackaddr) if (!ch.stackaddr)
{ {
@ -315,25 +315,25 @@ frok::parent (volatile char * volatile stack_here)
stack. If so, the entire stack is committed anyway and StackLimit stack. If so, the entire stack is committed anyway and StackLimit
points to the allocation address of the stack. Mark in guardsize that points to the allocation address of the stack. Mark in guardsize that
we must not set up guard pages. */ we must not set up guard pages. */
ch.stackaddr = ch.stacktop = NtCurrentTeb()->Tib.StackLimit; ch.stackaddr = ch.stacklimit = NtCurrentTeb()->Tib.StackLimit;
ch.guardsize = (size_t) -1; ch.guardsize = (size_t) -1;
} }
else else
{ {
/* Otherwise we're running on a system-allocated stack. Since stack_here /* Otherwise we're running on a system-allocated stack. Since stack_here
is the address of the stack pointer we start the child with anyway, we is the address of the stack pointer we start the child with anyway, we
can set ch.stacktop to this value rounded down to page size. The can set ch.stacklimit to this value rounded down to page size. The
child will not need the rest of the stack anyway. Guardsize depends child will not need the rest of the stack anyway. Guardsize depends
on whether we're running on a pthread or not. If pthread, we fetch on whether we're running on a pthread or not. If pthread, we fetch
the guardpage size from the pthread attribs, otherwise we use the the guardpage size from the pthread attribs, otherwise we use the
system default. */ system default. */
ch.stacktop = (void *) ((uintptr_t) stack_here & ~wincap.page_size ()); ch.stacklimit = (void *) ((uintptr_t) stack_here & ~wincap.page_size ());
ch.guardsize = (&_my_tls != _main_tls && _my_tls.tid) ch.guardsize = (&_my_tls != _main_tls && _my_tls.tid)
? _my_tls.tid->attr.guardsize ? _my_tls.tid->attr.guardsize
: wincap.def_guard_page_size (); : wincap.def_guard_page_size ();
} }
debug_printf ("stack - bottom %p, top %p, addr %p, guardsize %ly", debug_printf ("stack - bottom %p, top %p, addr %p, guardsize %ly",
ch.stackbottom, ch.stacktop, ch.stackaddr, ch.guardsize); ch.stackbase, ch.stacklimit, ch.stackaddr, ch.guardsize);
PROCESS_INFORMATION pi; PROCESS_INFORMATION pi;
STARTUPINFOW si; STARTUPINFOW si;
@ -475,7 +475,7 @@ frok::parent (volatile char * volatile stack_here)
impure_end = _impure_ptr + 1; impure_end = _impure_ptr + 1;
} }
rc = child_copy (hchild, true, rc = child_copy (hchild, true,
"stack", stack_here, ch.stackbottom, "stack", stack_here, ch.stackbase,
impure, impure_beg, impure_end, impure, impure_beg, impure_end,
NULL); NULL);