1 files changed, 73 insertions, 0 deletions
diff --git a/signal.c b/signal.c
new file mode 100644
index 0000000..6bca945
--- /dev/null
+++ b/signal.c
@@ -0,0 +1,73 @@
+/* signal.c: a Hugh-approved signal handler. */
+
+#include <signal.h>
+#include <setjmp.h>
+#include "rc.h"
+#include "sigmsgs.h"
+#include "jbwrap.h"
+
+Jbwrap slowbuf;
+volatile SIG_ATOMIC_T slow, interrupt_happened;
+void (*sighandlers[NUMOFSIGNALS])(int);
+
+static volatile SIG_ATOMIC_T sigcount, caught[NUMOFSIGNALS];
+
+extern void catcher(int s) {
+	if (caught[s] == 0) {
+		sigcount++;
+		caught[s] = 1;
+	}
+	signal(s, catcher);
+	interrupt_happened = TRUE;
+#ifndef SVSIGS
+	if (slow)
+		longjmp(slowbuf.j, 1);
+#endif
+}
+
+extern void sigchk() {
+	void (*h)(int);
+	int s, i;
+	if (sigcount == 0)
+		return; /* ho hum; life as usual */
+	if (forked)
+		exit(1); /* exit unconditionally on a signal in a child process */
+	for (i = 0, s = -1; i < NUMOFSIGNALS; i++)
+		if (caught[i] != 0) {
+			s = i;
+			--sigcount;
+			caught[s] = 0;
+			break;
+		}
+	if (s == -1)
+		panic("all-zero sig vector with nonzero sigcount");
+	if ((h = sighandlers[s]) == SIG_DFL)
+		panic("caught signal set to SIG_DFL");
+	if (h == SIG_IGN)
+		panic("caught signal set to SIG_IGN");
+	(*h)(s);
+}
+
+extern void (*rc_signal(int s, void (*h)(int)))(int) {
+	void (*old)(int);
+	sigchk();
+	old = sighandlers[s];
+	if (h == SIG_DFL || h == SIG_IGN) {
+		signal(s, h);
+		sighandlers[s] = h;
+	} else {
+		sighandlers[s] = h;
+		signal(s, catcher);
+	}
+	return old;
+}
+
+extern void initsignal() {
+	void (*h)(int);
+	int i;
+	for (i = 1; i < NUMOFSIGNALS; i++) {
+		if ((h = signal(i, SIG_DFL)) != SIG_DFL)
+			signal(i, h);
+		sighandlers[i] = h;
+	}
+}