perl 5.002beta1h patch: mg.c

Set up a reliable signal handler, courtesy of Kenneth Albanowski.
This needs to be documented still.  The idea is that even on
System V systems, you won't have to reset the signal handler as
the first action inside your signal handler.

diff --git a/mg.c b/mg.c
index d58b0cf..9461515 100644 (file)
--- a/mg.c
+++ b/mg.c
@@ -531,6 +531,49 @@ MAGIC* mg;
     return 0;
 }
 
+#ifdef HAS_SIGACTION
+/* set up reliable signal() clone */
+
+typedef void (*Sigfunc) _((int));
+
+static
+Sigfunc rsignal(signo,handler)
+int signo;
+Sigfunc handler;
+{
+    struct sigaction act,oact;
+    
+    act.sa_handler = handler;
+    sigemptyset(&act.sa_mask);
+    act.sa_flags = 0;
+#ifdef SIGALRM    
+    if (signo == SIGALRM) {
+#else
+    if (0) {
+#endif        
+#ifdef SA_INTERRUPT
+       act.sa_flags |= SA_INTERRUPT;   /* SunOS */
+#endif 
+    } else {
+#ifdef SA_RESTART
+       act.sa_flags |= SA_RESTART;     /* SVR4, 4.3+BSD */
+#endif
+    }
+    if (sigaction(signo, &act, &oact) < 0)
+       return(SIG_ERR);
+    else
+       return(oact.sa_handler);
+}
+
+#else
+
+/* ah well, so much for reliability */
+
+#define rsignal(x,y) signal(x,y)
+
+#endif
+
+
 int
 magic_setsig(sv,mg)
 SV* sv;
@@ -566,7 +609,7 @@ MAGIC* mg;
     }
     if (SvTYPE(sv) == SVt_PVGV || SvROK(sv)) {
        if (i)
-           (void)signal(i,sighandler);
+           (void)rsignal(i,sighandler);
        else
            *svp = SvREFCNT_inc(sv);
        return 0;
@@ -574,13 +617,13 @@ MAGIC* mg;
     s = SvPV_force(sv,na);
     if (strEQ(s,"IGNORE")) {
        if (i)
-           (void)signal(i,SIG_IGN);
+           (void)rsignal(i,SIG_IGN);
        else
            *svp = 0;
     }
     else if (strEQ(s,"DEFAULT") || !*s) {
        if (i)
-           (void)signal(i,SIG_DFL);
+           (void)rsignal(i,SIG_DFL);
        else
            *svp = 0;
     }
@@ -590,7 +633,7 @@ MAGIC* mg;
            sv_setpv(sv,tokenbuf);
        }
        if (i)
-           (void)signal(i,sighandler);
+           (void)rsignal(i,sighandler);
        else
            *svp = SvREFCNT_inc(sv);
     }