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Fixed vm86_enter race conditions.

This commit is contained in:
Ove Kaaven 2002-01-04 21:57:04 +00:00 committed by Alexandre Julliard
parent fcc148b283
commit 4eb0bebd90
2 changed files with 43 additions and 21 deletions
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61
dlls/ntdll/signal_i386.c
View File

@ -115,13 +115,17 @@ static inline int wine_sigaltstack( const struct sigaltstack *new,
}
#endif
int vm86_enter( struct vm86plus_struct *ptr );
void vm86_return();
#define VM86_EAX 0 /* the %eax value while vm86_enter is executing */
int vm86_enter( void **vm86_ptr );
void vm86_return(void);
void vm86_return_end(void);
__ASM_GLOBAL_FUNC(vm86_enter,
"pushl %ebp\n\t"
"movl %esp, %ebp\n\t"
"movl $166,%eax\n\t" /*SYS_vm86*/
"movl 8(%ebp),%ecx\n\t"
"movl 8(%ebp),%ecx\n\t" /* vm86_ptr */
"movl (%ecx),%ecx\n\t"
"pushl %ebx\n\t"
"movl $1,%ebx\n\t" /*VM86_ENTER*/
"pushl %ecx\n\t" /* put vm86plus_struct ptr somewhere we can find it */
@ -134,6 +138,16 @@ __ASM_GLOBAL_FUNC(vm86_enter,
"popl %ecx\n\t"
"popl %ebx\n\t"
"popl %ebp\n\t"
"testl %eax,%eax\n\t"
"jl 0f\n\t"
"cmpb $0,%al\n\t" /* VM86_SIGNAL */
"je " __ASM_NAME("vm86_enter") "\n\t"
"0:\n\t"
"movl 4(%esp),%ecx\n\t" /* vm86_ptr */
"movl $0,(%ecx)\n\t"
".globl " __ASM_NAME("vm86_return_end") "\n\t"
".type " __ASM_NAME("vm86_return_end") ",@function\n"
__ASM_NAME("vm86_return_end") ":\n\t"
"ret" );
#define __HAVE_VM86
@ -474,14 +488,18 @@ static void save_context( CONTEXT *context, const SIGCONTEXT *sigcontext )
#ifdef __HAVE_VM86
else if ((void *)EIP_sig(sigcontext) == vm86_return) /* vm86 mode */
{
/* retrieve pointer to vm86plus struct that was stored in vm86_enter */
struct vm86plus_struct *vm86 = *(struct vm86plus_struct **)(ESP_sig(sigcontext) + sizeof(int));
/* fetch the saved %fs on the stack */
fs = *(unsigned int *)ESP_sig(sigcontext);
__set_fs(fs);
/* get context from vm86 struct */
save_vm86_context( context, vm86 );
return;
if (EAX_sig(sigcontext) == VM86_EAX) {
struct vm86plus_struct *vm86;
__set_fs(fs);
/* retrieve pointer to vm86plus struct that was stored in vm86_enter
* (but we could also get if from teb->vm86_ptr) */
vm86 = *(struct vm86plus_struct **)(ESP_sig(sigcontext) + sizeof(int));
/* get context from vm86 struct */
save_vm86_context( context, vm86 );
return;
}
}
#endif /* __HAVE_VM86 */
@ -519,9 +537,11 @@ static void restore_context( const CONTEXT *context, SIGCONTEXT *sigcontext )
#ifdef __HAVE_VM86
/* check if exception occurred in vm86 mode */
if ((void *)EIP_sig(sigcontext) == vm86_return &&
IS_SELECTOR_SYSTEM(CS_sig(sigcontext)))
IS_SELECTOR_SYSTEM(CS_sig(sigcontext)) &&
EAX_sig(sigcontext) == VM86_EAX)
{
/* retrieve pointer to vm86plus struct that was stored in vm86_enter */
/* retrieve pointer to vm86plus struct that was stored in vm86_enter
* (but we could also get it from teb->vm86_ptr) */
struct vm86plus_struct *vm86 = *(struct vm86plus_struct **)(ESP_sig(sigcontext) + sizeof(int));
restore_vm86_context( context, vm86 );
return;
@ -807,8 +827,10 @@ static void set_vm86_pend( CONTEXT *context )
if (context->EFlags & VIF_MASK) {
/* VIF is set, throw exception */
teb->vm86_pending = 0;
teb->vm86_ptr = NULL;
rec.ExceptionAddress = (LPVOID)context->Eip;
EXC_RtlRaiseException( &rec, context );
teb->vm86_ptr = vm86;
}
}
else if (vm86)
@ -816,18 +838,22 @@ static void set_vm86_pend( CONTEXT *context )
/* not in VM86, but possibly setting up for it */
if (vm86->regs.eflags & VIP_MASK) return;
vm86->regs.eflags |= VIP_MASK;
if (((char*)context->Eip >= (char*)vm86_return) &&
((char*)context->Eip <= (char*)vm86_return_end) &&
(VM86_TYPE(context->Eax) != VM86_SIGNAL)) {
/* exiting from VM86, can't throw */
return;
}
if (vm86->regs.eflags & VIF_MASK) {
/* VIF is set, throw exception */
CONTEXT vcontext;
teb->vm86_pending = 0;
teb->vm86_ptr = NULL;
save_vm86_context( &vcontext, vm86 );
rec.ExceptionAddress = (LPVOID)vcontext.Eip;
EXC_RtlRaiseException( &rec, &vcontext );
teb->vm86_ptr = vm86;
restore_vm86_context( &vcontext, vm86 );
if (teb->vm86_ctx) {
/* must also save here */
*(CONTEXT*)(teb->vm86_ctx) = vcontext;
}
}
}
}
@ -1065,7 +1091,7 @@ void __wine_enter_vm86( CONTEXT *context )
do
{
res = vm86_enter( &vm86 );
res = vm86_enter( &teb->vm86_ptr ); /* uses and clears teb->vm86_ptr */
if (res < 0)
{
errno = -res;
@ -1073,10 +1099,7 @@ void __wine_enter_vm86( CONTEXT *context )
}
} while (VM86_TYPE(res) == VM86_SIGNAL);
teb->vm86_ctx = context;
save_vm86_context( context, &vm86 );
teb->vm86_ptr = NULL;
teb->vm86_ctx = NULL;
context->EFlags |= teb->vm86_pending;
switch(VM86_TYPE(res))

3
include/thread.h
View File

@ -101,11 +101,10 @@ typedef struct _TEB
DWORD alarms; /* --3 22c Data for vm86 mode */
DWORD vm86_pending; /* --3 230 Data for vm86 mode */
void *vm86_ptr; /* --3 234 Data for vm86 mode */
void *vm86_ctx; /* --3 238 Data for vm86 mode */
/* here is plenty space for wine specific fields (don't forget to change pad6!!) */
/* the following are nt specific fields */
DWORD pad6[623]; /* --n 23c */
DWORD pad6[624]; /* --n 238 */
UNICODE_STRING StaticUnicodeString; /* -2- bf8 used by advapi32 */
USHORT StaticUnicodeBuffer[261]; /* -2- c00 used by advapi32 */
DWORD pad7; /* --n e0c */