Ticket #10031: sig_except.patch

c_lib/include/interrupt.h

@@ -26 +26 @@
    to get signal handling capabilities. 
 
    VERY VERY IMPORTANT:  
-       1. These *must* always come in pairs. E.g., if you have just 
-          a _sig_off without a corresponding _sig_on, then ctrl-c
-          later in the interpreter will sigfault!
+       1. These *must* always come in pairs.
 
        2. Do *not* put these in the __init__ method of a Pyrex extension
           class, or you'll get crashes. 
 
        3. Do not put these around any non-pure C code!!!!
-
-       4. If you need to do a check of control-c inside a loop, e.g.,
-          when constructing a matrix, put _sig_check instead of using
-          _sig_on then _sig_off.
 */
 
 /**
@@ -164 +158 @@
 
 /**
  * Enables SAGE signal handling for the following C block. This macro
- * *MUST* be followed by _sig_off.
+ * *MUST* be followed by ``_sig_off``.
  *
+ * INPUT:
  *
- * See also @ref _sig_str
+ *  - ``str`` - a string to be displayed as error message when the code
+ *    between ``_sig_on`` and ``_sig_off`` fails.
+ *
+ *  - ``except`` - the value to return when an exception is raised.
+ *    This should correspond to the "except" value in the Cython
+ *    declaration of the function.  For example, the function
+ *    cdef int my_cython_function() except -1:
+ *    should use ``except`` = -1.
+ *    A function which return a Python object should NOT have an except
+ *    declaration and should use ``except`` = 0:
+ *    cdef function_returning_a_python_object():
+ *
+ * This is the most general macro, in practice you must use one of the
+ * shortcuts macros like ``_sig_on`` defined later.
+ *
  */
-
-/* The function sigsetjmp() below can return the following:
+#define _sig_on_str_except(str, except) \
+    if (_signals.mpio == 0) { \
+        _signals.mpio = 1+2; _signals.s = str;\
+        if (sigsetjmp(_signals.env,1) > 0) { \
+            _signals.mpio = 0;   \
+            return(except); \
+     } }
+/* The function sigsetjmp() in the macro above can return the following:
  *  - zero: this happens in the actual _sig_on call and sets up the
  *    address for the Sage signal handler to jump to.  The program
  *    continues normally.
@@ -183 +198 @@
  *    this case, the program continues as if nothing happened between
  *    _sig_on and _sig_retry.
  */
-#define _sig_on if (_signals.mpio == 0) { _signals.mpio = 1+2; _signals.s = NULL;\
-                 if (sigsetjmp(_signals.env,1) > 0) { \
-                  _signals.mpio = 0;   \
-                  return(0); \
-                } } // else { _signals.s = "Unbalanced _sig_on/_sig_off\n"; fprintf(stderr, _signals.s); sage_signal_handler(SIGABRT); }
 
-/* /\** */
-/*  * Enables SAGE signal handling for the following C block. This macro */
-/*  * *MUST* be followed by _sig_off_short. */
-/*  * */
-/*  * If the following block takes very little time to compute this macro */
-/*  * is the right choice. Otherwise _sig_on is appropriate. */
-/*  * */
-/*  * See also _sig_on and _sig_str. */
-/*  * */
-/*  *\/ */
 
-/* #define _sig_on_short _signals.mpio = 1 */
-
-
-/**
- * Same as @ref _sig_on but with string support
- *
- */
- 
-#define _sig_str(mstring) if (_signals.mpio == 0) { _signals.mpio = 1+2; \
-                _signals.s = mstring; \
-                if (sigsetjmp(_signals.env,1) > 0) { \
-                  _signals.mpio = 0; \
-                 return(0); \
-                } } //else { _signals.s = "Unbalanced _sig_str/_sig_off\n"; fprintf(stderr, _signals.s); sage_signal_handler(SIGABRT); }
+/* Some very useful shortcuts.
+ * Note that we need to define the except values with a type in
+ * sage/ext/interrupt.pxi, but we can define the macros the same
+ * regardless of the type. */
+#define _sig_on _sig_on_str_except(NULL, 0)
+#define _sig_str(str) _sig_on_str_except(str, 0)
+#define _sig_on_except_int(except) _sig_on_str_except(NULL, except)
+#define _sig_str_except_int(str, except) _sig_on_str_except(str, except)
 
 
 /*
@@ -229 +223 @@
 #define SAGE_SIGNAL_HANDLER_MESSAGE_LEN 256
 
 
-/**
- *
- *
- */
-
 #define _sig_off _signals.mpio = 0; 
 
 
-/* /\** */
-/*  * */
-/*  * */
-/*  *\/ */
-
-/* #define _sig_off_short (_signals.mpio & 4) */
-
-
-/**
- *
- *
- */
-
-#define _sig_check _sig_on _sig_off
 
 /* Retry a failed computation starting from the last _sig_on.  The
  * program will continue as if nothing happened between _sig_on and

c_lib/src/interrupt.c

@@ -12 +12 @@
 #include "stdsage.h"
 #include "interrupt.h"
 #include <stdio.h>
+#include <execinfo.h>
 
 
 char sage_signal_handler_message[SAGE_SIGNAL_HANDLER_MESSAGE_LEN + 1] = "";
@@ -29 +30 @@
 void msg(char* s);
 
 void sage_signal_handler(int sig) {
+  void* backtracebuffer[1024];
 
   char *s = _signals.s;
   _signals.s = NULL;
@@ -38 +40 @@
   {
      s = sage_signal_handler_message;
   }
+  
+  if (sig == SIGINT)
+  {
+    fprintf(stderr, "\n*** SIGINT *** %s _sig_on\n",  (_signals.mpio & 1) ? "inside" : "outside");
+    int btsize = backtrace(backtracebuffer, 1024);
+    backtrace_symbols_fd(backtracebuffer, btsize, 2);
+    fflush(stderr);
+  }
 
   //we override the default handler
   if ( _signals.mpio & 1 ) {
@@ -104 +114 @@
       break;
     default:
       _signals.python_handler(sig);
+      fprintf(stderr, "*** Python signal handler finished\n"); fflush(stderr);
       break;
     };
     

sage/ext/interrupt.pxi

@@ -5 +5 @@
 ################################################################
 
 cdef extern from 'interrupt.h':
-    int _sig_on, _sig_off, _sig_check, _sig_retry
-    void _sig_str(char*)
+    int _sig_on
+    int _sig_str(char*)
+    int _sig_on_except_int(int)
+    int _sig_str_except_int(char*, int)
+    int _sig_off, _sig_retry

sage/libs/singular/polynomial.pyx

@@ -314 +314 @@
     if(r != currRing): rChangeCurrRing(r)
     cdef int count = singular_polynomial_length_bounded(p,15)
     if count >= 15 or exp > 15:
-        _sig_on
+        _sig_on_except_int(-1)
     ret[0] = pPower( p_Copy(p,r), exp)
     if count >= 15 or exp > 15:
         _sig_off