1 files changed, 48 insertions, 0 deletions
diff --git a/portbash/pgrp.c b/portbash/pgrp.c
new file mode 100644
index 0000000..5198dd6
--- /dev/null
+++ b/portbash/pgrp.c
@@ -0,0 +1,48 @@
+/*
+ * If this system has a BSD-style getpgrp() call which takes a pid
+ * as an argument, output a -DBSD_GETPGRP.
+ */
+#include <stdio.h>
+#include <sys/types.h>
+
+int     pid;
+int     pg1, pg2, pg3, pg4;
+int     ng, np, s, child;
+
+main()
+{
+	pid = getpid();
+	pg1 = getpgrp(0);
+	pg2 = getpgrp();
+	pg3 = getpgrp(pid);
+	pg4 = getpgrp(1);
+
+	/*
+	 * If all of these values are the same, it's pretty sure that
+	 * we're on a system that ignores getpgrp's first argument.
+	 */
+	if (pg2 == pg4 && pg1 == pg3 && pg2 == pg3)
+		exit(0);
+
+	child = fork();
+	if (child < 0)
+		exit(1);
+	else if (child == 0) {
+		np = getpid();
+		/*
+		 * If this is Sys V, this will not work; pgrp will be
+		 * set to np because setpgrp just changes a pgrp to be
+		 * the same as the pid.
+		 */
+		setpgrp(np, pg1);
+		ng = getpgrp(0);	/* Same result for Sys V and BSD */
+		if (ng == pg1) {
+			printf("-DBSD_GETPGRP\n");
+			exit(0);
+		} else
+			exit(1);
+	} else {
+		wait(&s);
+		exit(s>>8);
+	}
+}