RAND_load_file(3) — Subroutines

NAME

RAND_load_file, RAND_write_file, RAND_file_name − PRNG seed file

SYNOPSIS

#include <openssl/rand.h>
const char ∗RAND_file_name(
        char ∗buf, size_t num ); int RAND_load_file(
        const char ∗filename, long max_bytes ); int RAND_write_file(
        const char ∗filename );

DESCRIPTION

The RAND_load_file() function reads a number of bytes from file filename and adds them to the PRNG. If max_bytes is non-negative, up to max_bytes are read; starting with OpenSSL 0.9.5, if max_bytes is -1, the complete file is read.

The RAND_write_file() function writes a number of random bytes (currently 1024) to file filename which can be used to initialize the PRNG by calling RAND_load_file() in a later session.

The RAND_file_name() function generates a default path for the random seed file. buf points to a buffer of size num in which to store the filename. The seed file is $RANDFILE if that environment variable is set, $HOME/.rnd otherwise. If $HOME is not set either, or num is too small for the path name, an error occurs.

RETURN VALUES

The RAND_load_file() function returns the number of bytes read.

The RAND_write_file() function returns the number of bytes written, and -1 if the bytes written were generated without appropriate seed.

The RAND_file_name() function returns a pointer to buf on success, and NULL on error.

HISTORY

The RAND_load_file(), RAND_write_file(), and RAND_file_name() functions are available in all versions of SSLeay and OpenSSL.

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