New file. As yet unused.

1 files changed, 31 insertions, 0 deletions

diff --git a/lib/stdopen.c b/lib/stdopen.c
new file mode 100644
index 000000000..6cf521896
--- /dev/null
+++ b/lib/stdopen.c
@@ -0,0 +1,31 @@
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+/* Try to ensure that each of the standard file numbers (0, 1, 2)
+   is in use.  Without this, each application would have to guard
+   every call to open, dup, and fopen with tests to ensure they don't
+   use one of the special file numbers when opening a user's file.  */
+void
+stdopen (void)
+{
+  int fd;
+  for (fd = 0; fd <= 2; fd++)
+    {
+      struct stat sb;
+      if (fstat (fd, &sb) < 0)
+	{
+	  static const int flag[] = { O_WRONLY, O_RDONLY, O_RDONLY };
+	  /* FIXME: worry about errno != EBADF?  */
+	  char const *file = "/dev/null";
+	  int fd2 = open (file, flag[fd]);
+	  if (fd2 < 0)
+	    break;
+	  if (fd2 != fd)
+	    {
+	      close (fd2);
+	      break;
+	    }
+	}
+    }
+}