X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=fd.c;h=6042a58f531af44e941f012fdc273d78c2f9fb37;hp=d0b5c895a5f25d02b9f566fbe693a38898057203;hb=6bdac07456cb5872f824028912d1049883a9c21f;hpb=cb4dd13c2327c13d486b6abe572f4af2398b65de

diff --git a/fd.c b/fd.c
index d0b5c895..6042a58f 100644
--- a/fd.c
+++ b/fd.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2006-2008 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2006-2009 Andre Noll <maan@systemlinux.org>
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
@@ -427,3 +427,24 @@ again:
 		goto again;
 	return ret;
 }
+
+/**
+ * Ensure that file descriptors 0, 1, and 2 are valid.
+ *
+ * Common approach that opens /dev/null until it gets a file descriptor greater
+ * than two.
+ *
+ * \sa okir's Black Hats Manual.
+ */
+void valid_fd_012(void)
+{
+	while (1) {
+		int fd = open("/dev/null", O_RDWR);
+		if (fd < 0)
+			exit(EXIT_FAILURE);
+		if (fd > 2) {
+			close(fd);
+			break;
+		}
+	}
+}