bug 1225957

1 files changed, 97 insertions, 105 deletions

diff --git a/win/tclWinChan.c b/win/tclWinChan.c
index c4ec930..db8b75b 100644
--- a/win/tclWinChan.c
+++ b/win/tclWinChan.c
@@ -9,7 +9,7 @@
  * See the file "license.terms" for information on usage and redistribution
  * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclWinChan.c,v 1.42 2005/06/08 14:12:19 dkf Exp $
+ * RCS: @(#) $Id: tclWinChan.c,v 1.43 2005/06/23 19:48:50 kennykb Exp $
  */
 
 #include "tclWinInt.h"
@@ -127,16 +127,24 @@ static Tcl_ChannelType fileChannelType = {
     FileTruncateProc,		/* Truncate proc. */
 };
 
-#if defined(HAVE_NO_SEH) && defined(TCL_MEM_DEBUG)
-static void *INITIAL_ESP, *INITIAL_EBP, *INITIAL_HANDLER;
-static void *RESTORED_ESP, *RESTORED_EBP, *RESTORED_HANDLER;
-#endif /* HAVE_NO_SEH && TCL_MEM_DEBUG */
-
 #ifdef HAVE_NO_SEH
-static __attribute__ ((cdecl)) EXCEPTION_DISPOSITION
-_except_makefilechannel_handler(struct _EXCEPTION_RECORD *ExceptionRecord,
-	void *EstablisherFrame, struct _CONTEXT *ContextRecord,
-	void *DispatcherContext);
+
+/*
+ * Unlike Borland and Microsoft, we don't register exception handlers
+ * by pushing registration records onto the runtime stack.  Instead, we
+ * register them by creating an EXCEPTION_REGISTRATION within the activation
+ * record.
+ */
+
+typedef struct EXCEPTION_REGISTRATION {
+    struct EXCEPTION_REGISTRATION* link;
+    EXCEPTION_DISPOSITION (*handler)( struct _EXCEPTION_RECORD*, void*,
+				      struct _CONTEXT*, void* );
+    void* ebp;
+    void* esp;
+    int status;
+} EXCEPTION_REGISTRATION;
+
 #endif
 
 /*
@@ -1049,6 +1057,9 @@ Tcl_MakeFileChannel(rawHandle, mode)
 					 * and TCL_WRITABLE to indicate file
 					 * mode. */
 {
+#ifdef HAVE_NO_SEH
+    EXCEPTION_REGISTRATION registration;
+#endif
     char channelName[16 + TCL_INTEGER_SPACE];
     Tcl_Channel channel = NULL;
     HANDLE handle = (HANDLE) rawHandle;
@@ -1137,81 +1148,93 @@ Tcl_MakeFileChannel(rawHandle, mode)
 	 * of this duped handle which might throw EXCEPTION_INVALID_HANDLE.
 	 */
 
-#ifdef HAVE_NO_SEH
-# ifdef TCL_MEM_DEBUG
-	__asm__ __volatile__ (
-	    "movl %%esp,  %0" "\n\t"
-	    "movl %%ebp,  %1" "\n\t"
-	    "movl %%fs:0, %2" "\n\t"
-	    : "=m"(INITIAL_ESP),
-	      "=m"(INITIAL_EBP),
-	      "=r"(INITIAL_HANDLER) );
-# endif /* TCL_MEM_DEBUG */
-
-	__asm__ __volatile__ (
-	    "pushl %%ebp" "\n\t"
-	    "pushl %0" "\n\t"
-	    "pushl %%fs:0" "\n\t"
-	    "movl  %%esp, %%fs:0"
-	    :
-	    : "r" (_except_makefilechannel_handler) );
-	result = CloseHandle(dupedHandle);
-	__asm__ __volatile__ (
-	    "jmp  makefilechannel_pop" "\n"
-	"makefilechannel_reentry:" "\n\t"
-	    "movl %%fs:0, %%eax" "\n\t"
-	    "movl 0x8(%%eax), %%esp" "\n\t"
-	    "movl 0x8(%%esp), %%ebp" "\n"
-	    "movl $0, %0" "\n"
-	"makefilechannel_pop:" "\n\t"
-	    "movl (%%esp), %%eax" "\n\t"
-	    "movl %%eax, %%fs:0" "\n\t"
-	    "add  $12, %%esp" "\n\t"
-	    : "=m"(result)
-	    :
-	    : "%eax");
-
-# ifdef TCL_MEM_DEBUG
+	result = 0;
+#ifndef HAVE_NO_SEH
+	__try {
+	    CloseHandle(dupedHandle);
+	    result = 1;
+	} __except (EXCEPTION_EXECUTE_HANDLER) {}
+#else
+	/*
+	 * Don't have SEH available, do things the hard way.
+	 * Note that this needs to be one block of asm, to avoid stack
+	 * imbalance; also, it is illegal for one asm block to contain 
+	 * a jump to another.
+	 */
+	
 	__asm__ __volatile__ (
-	    "movl  %%esp,  %0" "\n\t"
-	    "movl  %%ebp,  %1" "\n\t"
-	    "movl  %%fs:0, %2" "\n\t"
-	    : "=m"(RESTORED_ESP),
-	      "=m"(RESTORED_EBP),
-	      "=r"(RESTORED_HANDLER) );
-
-	if (INITIAL_ESP != RESTORED_ESP) {
-	    Tcl_Panic("ESP restored incorrectly");
-	}
-	if (INITIAL_EBP != RESTORED_EBP) {
-	    Tcl_Panic("EBP restored incorrectly");
-	}
-	if (INITIAL_HANDLER != RESTORED_HANDLER) {
-	    Tcl_Panic("HANDLER restored incorrectly");
-	}
-# endif /* TCL_MEM_DEBUG */
 
-	if (result == 0) {
 	    /*
-	     * The handle failed to close.  The original is therefore
-	     * invalid.
+	     * Pick up parameters before messing with the stack
 	     */
 
-	    return NULL;
-	}
+	    "movl       %[dupedHandle], %%ebx"          "\n\t"
 
-#else
-	__try {
-	    result = CloseHandle(dupedHandle);
-	} __except (EXCEPTION_EXECUTE_HANDLER) {
 	    /*
-	     * Definately an invalid handle.  So, therefore, the original
-	     * is invalid also.
+	     * Construct an EXCEPTION_REGISTRATION to protect the
+	     * call to CloseHandle
 	     */
+	    "leal       %[registration], %%edx"         "\n\t"
+	    "movl       %%fs:0,         %%eax"          "\n\t"
+	    "movl       %%eax,          0x0(%%edx)"     "\n\t" /* link */
+	    "leal       1f,             %%eax"          "\n\t"
+	    "movl       %%eax,          0x4(%%edx)"     "\n\t" /* handler */
+	    "movl       %%ebp,          0x8(%%edx)"     "\n\t" /* ebp */
+	    "movl       %%esp,          0xc(%%edx)"     "\n\t" /* esp */
+	    "movl       $0,             0x10(%%edx)"    "\n\t" /* status */
+	
+	    /* Link the EXCEPTION_REGISTRATION on the chain */
+	    
+	    "movl       %%edx,          %%fs:0"         "\n\t"
+	    
+	    /* Call CloseHandle( dupedHandle ) */
+	    
+	    "pushl      %%ebx"                          "\n\t"
+	    "call       _CloseHandle@4"                 "\n\t"
+	    
+	    /* 
+	     * Come here on normal exit.  Recover the EXCEPTION_REGISTRATION
+	     * and put a TRUE status return into it.
+	     */
+	    
+	    "movl       %%fs:0,         %%edx"          "\n\t"
+	    "movl	$1,		%%eax"		"\n\t"
+	    "movl       %%eax,          0x10(%%edx)"    "\n\t"
+	    "jmp        2f"                             "\n"
+	    
+	    /*
+	     * Come here on an exception.  Recover the EXCEPTION_REGISTRATION
+	     */
+	    
+	    "1:"                                        "\t"
+	    "movl       %%fs:0,         %%edx"          "\n\t"
+	    "movl       0x8(%%edx),     %%edx"          "\n\t"
+	    
+	    /* 
+	     * Come here however we exited.  Restore context from the
+	     * EXCEPTION_REGISTRATION in case the stack is unbalanced.
+	     */
+	    
+	    "2:"                                        "\t"
+	    "movl       0xc(%%edx),     %%esp"          "\n\t"
+	    "movl       0x8(%%edx),     %%ebp"          "\n\t"
+	    "movl       0x0(%%edx),     %%eax"          "\n\t"
+	    "movl       %%eax,          %%fs:0"         "\n\t"
+	    
+	    :
+	    /* No outputs */
+	    :
+	    [registration]  "m"     (registration),
+	    [dupedHandle]   "m"	    (dupedHandle)
+	    :
+	    "%eax", "%ebx", "%ecx", "%edx", "%esi", "%edi", "memory"
+	    );
+	result = registration.status;
 
+#endif
+	if (result == FALSE) {
 	    return NULL;
 	}
-#endif /* HAVE_NO_SEH */
 
 	/* Fall through, the handle is valid. */
 
@@ -1229,37 +1252,6 @@ Tcl_MakeFileChannel(rawHandle, mode)
 /*
  *----------------------------------------------------------------------
  *
- * _except_makefilechannel_handler --
- *
- *	SEH exception handler for Tcl_MakeFileChannel.
- *
- * Results:
- *	See Tcl_MakeFileChannel.
- *
- * Side effects:
- *	See Tcl_MakeFileChannel.
- *
- *----------------------------------------------------------------------
- */
-#ifdef HAVE_NO_SEH
-static
-__attribute__ ((cdecl))
-EXCEPTION_DISPOSITION
-_except_makefilechannel_handler(
-    struct _EXCEPTION_RECORD *ExceptionRecord,
-    void *EstablisherFrame,
-    struct _CONTEXT *ContextRecord,
-    void *DispatcherContext)
-{
-    __asm__ __volatile__ (
-	    "jmp makefilechannel_reentry");
-    return 0; /* Function does not return */
-}
-#endif
-
-/*
- *----------------------------------------------------------------------
- *
  * TclpGetDefaultStdChannel --
  *
  *	Constructs a channel for the specified standard OS handle.