Re: hangling interrupt

[Bill Allombert <allomber@math.u-bordeaux.fr>]

On Mon, Dec 05, 2005 at 04:40:09PM -0500, Igor Schein wrote:
> Hi,
> 
> Don't try this in a gp session you care about:
> 
> k=0;while(k++,print(k);system("sleep 1"))
> 
> Now that's what I call a true infinite loop, the one you cannot break
> out of. Even ^\ doesn't work, only ^Z and good-bye session.  I have a
> feeling it's non-trivial to handle this scenario properly.

The attached path should fix that provided a suitable
has_waitpid.c file is provided, and /bin/sh is a shell.

I am not sure it is worth the hassle though...

Cheers,
Bill.

Index: src/gp/gp.c
===================================================================
RCS file: /home/cvs/pari/src/gp/gp.c,v
retrieving revision 1.279
diff -u -r1.279 gp.c
--- src/gp/gp.c	22 Nov 2005 09:23:06 -0000	1.279
+++ src/gp/gp.c	6 Dec 2005 23:37:53 -0000
@@ -24,6 +24,12 @@
 #include "gp.h"
 #include "../graph/rect.h"
 
+#define HAS_WAITPID
+#ifdef HAS_WAITPID
+#  include <unistd.h>
+#  include <sys/types.h>
+#  include <sys/wait.h>
+#endif
 #ifdef _WIN32
 #  include <windows.h>
 #  ifndef WINCE
@@ -1698,7 +1704,16 @@
 void
 system0(char *s)
 {
-#if defined(UNIX) || defined(__EMX__) || defined(_WIN32)
+#ifdef HAS_WAITPID
+  pid_t pid;
+  int status;
+  check_secure(s); 
+  if (!(pid=fork()))
+    execl("/bin/sh","sh","-c",s,NULL);
+  waitpid(pid,&status,0);
+  if (WIFSIGNALED(status) && WTERMSIG(status)>0)
+    sigint_fun();
+#elif defined(UNIX) || defined(__EMX__) || defined(_WIN32)
   check_secure(s); system(s);
 #else
   err(archer);