Copy a few files from LPlib (a new project of mine), add a wrapper.

Now we have directory reading capabilities for VMS as well, and all
of it in a fairly general manner.

crypto/LPdir_unix.c

@@ -0,0 +1,105 @@
+/* $LP: LPlib/source/LPdir_unix.c,v 1.6 2004/06/14 10:08:43 _cvs_levitte Exp $ */
+/*
+ * Copyright (c) 2004, Richard Levitte <richard@levitte.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <dirent.h>
+#include <errno.h>
+#ifndef LPDIR_H
+#include "LPdir.h"
+#endif
+
+struct LP_dir_context_st
+{
+  DIR *dir;
+  char entry_name[NAME_MAX+1];
+};
+
+const char *LP_find_file(LP_DIR_CTX **ctx, const char *directory)
+{
+  struct dirent *direntry = NULL;
+
+  if (ctx == NULL || directory == NULL)
+    {
+      errno = EINVAL;
+      return 0;
+    }
+
+  errno = 0;
+  if (*ctx == NULL)
+    {
+      *ctx = (LP_DIR_CTX *)malloc(sizeof(LP_DIR_CTX));
+      if (*ctx == NULL)
+	{
+	  errno = ENOMEM;
+	  return 0;
+	}
+      memset(*ctx, '\0', sizeof(LP_DIR_CTX));
+
+      (*ctx)->dir = opendir(directory);
+      if ((*ctx)->dir == NULL)
+	{
+	  int save_errno = errno; /* Probably not needed, but I'm paranoid */
+	  free(*ctx);
+	  *ctx = NULL;
+	  errno = save_errno;
+	  return 0;
+	}
+    }
+
+  direntry = readdir((*ctx)->dir);
+  if (direntry == NULL)
+    {
+      return 0;
+    }
+
+  strncpy((*ctx)->entry_name, direntry->d_name, sizeof((*ctx)->entry_name));
+  return (*ctx)->entry_name;
+}
+
+int LP_find_file_end(LP_DIR_CTX **ctx)
+{
+  if (ctx != NULL && *ctx != NULL)
+    {
+      int ret = closedir((*ctx)->dir);
+
+      free(*ctx);
+      switch (ret)
+	{
+	case 0:
+	  return 1;
+	case -1:
+	  return 0;
+	default:
+	  break;
+	}
+    }
+  errno = EINVAL;
+  return 0;
+}