Use a single set of FDs for all random plugin RNG instances

src/libstrongswan/plugins/random/random_plugin.c

@@ -15,9 +15,24 @@
 
 #include "random_plugin.h"
 
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+
 #include <library.h>
+#include <debug.h>
 #include "random_rng.h"
 
+#ifndef DEV_RANDOM
+# define DEV_RANDOM "/dev/random"
+#endif
+
+#ifndef DEV_URANDOM
+# define DEV_URANDOM "/dev/urandom"
+#endif
+
 typedef struct private_random_plugin_t private_random_plugin_t;
 
 /**
@@ -31,6 +46,41 @@ struct private_random_plugin_t {
 	random_plugin_t public;
 };
 
+/** /dev/random file descriptor */
+static int dev_random = -1;
+/** /dev/urandom file descriptor */
+static int dev_urandom = -1;
+
+/**
+ * See header.
+ */
+int random_plugin_get_dev_random()
+{
+	return dev_random;
+}
+
+/**
+ * See header.
+ */
+int random_plugin_get_dev_urandom()
+{
+	return dev_urandom;
+}
+
+/**
+ * Open a random device file
+ */
+static bool open_dev(char *file, int *fd)
+{
+	*fd = open(file, O_RDONLY);
+	if (*fd == -1)
+	{
+		DBG1(DBG_LIB, "opening \"%s\" failed: %s", file, strerror(errno));
+		return FALSE;
+	}
+	return TRUE;
+}
+
 METHOD(plugin_t, get_name, char*,
 	private_random_plugin_t *this)
 {
@@ -52,6 +102,14 @@ METHOD(plugin_t, get_features, int,
 METHOD(plugin_t, destroy, void,
 	private_random_plugin_t *this)
 {
+	if (dev_random != -1)
+	{
+		close(dev_random);
+	}
+	if (dev_urandom != -1)
+	{
+		close(dev_urandom);
+	}
 	free(this);
 }
 
@@ -72,6 +130,13 @@ plugin_t *random_plugin_create()
 		},
 	);
 
+	if (!open_dev(DEV_URANDOM, &dev_urandom) ||
+		!open_dev(DEV_RANDOM, &dev_random))
+	{
+		destroy(this);
+		return NULL;
+	}
+
 	return &this->public.plugin;
 }