Support for seed file writing and reading in Entropy
diff --git a/include/polarssl/entropy.h b/include/polarssl/entropy.h
index 039f5cd..ed97dca 100644
--- a/include/polarssl/entropy.h
+++ b/include/polarssl/entropy.h
@@ -39,6 +39,7 @@
#define POLARSSL_ERR_ENTROPY_SOURCE_FAILED -0x003C /**< Critical entropy source failure. */
#define POLARSSL_ERR_ENTROPY_MAX_SOURCES -0x003E /**< No more sources can be added. */
#define POLARSSL_ERR_ENTROPY_NO_SOURCES_DEFINED -0x0040 /**< No sources have been added to poll. */
+#define POLARSSL_ERR_ENTROPY_FILE_IO_ERROR -0x0058 /**< Read/write error in file. */
#if !defined(POLARSSL_CONFIG_OPTIONS)
#define ENTROPY_MAX_SOURCES 20 /**< Maximum number of sources supported */
@@ -47,6 +48,7 @@
#define ENTROPY_BLOCK_SIZE 64 /**< Block size of entropy accumulator (SHA-512) */
+#define ENTROPY_MAX_SEED_SIZE 1024 /**< Maximum size of seed we read from seed file */
#define ENTROPY_SOURCE_MANUAL ENTROPY_MAX_SOURCES
#ifdef __cplusplus
@@ -146,6 +148,34 @@
int entropy_update_manual( entropy_context *ctx,
const unsigned char *data, size_t len );
+#if defined(POLARSSL_FS_IO)
+/**
+ * \brief Write a seed file
+ *
+ * \param ctx Entropy context
+ * \param path Name of the file
+ *
+ * \return 0 if successful,
+ * POLARSSL_ERR_ENTROPY_FILE_IO_ERROR on file error, or
+ * POLARSSL_ERR_ENTROPY_SOURCE_FAILED
+ */
+int entropy_write_seed_file( entropy_context *ctx, const char *path );
+
+/**
+ * \brief Read and update a seed file. Seed is added to this
+ * instance. No more than ENTROPY_MAX_SEED_SIZE bytes are
+ * read from the seed file. The rest is ignored.
+ *
+ * \param ctx Entropy context
+ * \param path Name of the file
+ *
+ * \return 0 if successful,
+ * POLARSSL_ERR_ENTROPY_FILE_IO_ERROR on file error,
+ * POLARSSL_ERR_ENTROPY_SOURCE_FAILED
+ */
+int entropy_update_seed_file( entropy_context *ctx, const char *path );
+#endif
+
#ifdef __cplusplus
}
#endif