certificate.h

#ifndef CERTIFICATE
#define CERTIFICATE

#include <dirent.h>
#include <openssl/x509v3.h>

/**
 * Check if null terminated string ends with ".pem".
 * @param path String to check for ".pem".
 * @return 1 if last four chars are ".pem", else 0.
 */
int is_pem_file(char* path);

/**
 * Searches cert_list for the certificate that isn't a CA (the end entity).
 * If a certificate is not a CA, it is assumed to be the end entity. 
 * @param cert_list Array of certificates to search.
 * @return The index of the end cert or -1 on error.
 */
int get_end_entity(X509** cert_list, int num_certs);

/**
 * Get number of files in directory.
 * @param directory An open directory containing certificate files. 
 * @returns number of files in directory.
 */
int get_directory_size(DIR* directory);

/**
 * Reads a directory of certificate files, converts them to X509 certificates, 
 * and adds them to cert_list. 
 * @param cert_list Array of certificate pointers to be populated with certificates in directory.
 * @param directory The directory containing certificates to put into cert_list.
 * @param dir_name Path of directory.
 * @return 0 on success, else -1. 
 */
int get_directory_certs(X509** cert_list, DIR* directory, char* dir_name);

/**
 * Sorts certificates and loads them in order (from end entity to root) into a context.
 * @param ctx Context to load certificates into.
 * @param cert_list Array of certificates to load into context.
 * @param num_certs Number of certificates in cert_list array.
 * @return 1 on success, 0 on error.
 */
int add_directory_certs(SSL_CTX* ctx, X509** cert_list, int num_certs);

/**
 * Loads a private key into SSL_CTX, verifies the key matches the last certificate 
 * chain loaded in ctx, and builds the certificate chain. This function should be 
 * called after a certificate is loaded into the CTX. 
 * @param ctx The context the private key will be loaded into.
 * @param key_path Path to private key file. This file should be PEM or DER (ASN1).
 * @return 1 on success, 0 on error.
 */
int load_private_key(SSL_CTX* ctx, char* key_path);

/**
 * A certificate file or directory is loaded into ctx. The private key should
 * be loaded into ctx after this function is called. 
 * @param ctx The context that certificates will be loaded into.
 * @param path The path to a PEM file or directory containing all certificates
 * in the chain to be loaded into ctx.
 * @returns 1 on success, 0 on error.
 */
int load_certificates(SSL_CTX* ctx, char* path);

/**
 * A directory containing certificate files is loaded into ctx. The private key 
 * should be loaded into ctx after this function is called. 
 * @param ctx The context that certificates will be loaded into.
 * @param path The path to a directory containing all certificates
 * in the chain to be loaded into ctx.
 * @returns 1 on success, 0 on error.
 */
int load_directory_certs(SSL_CTX* ctx, char* path);

#endif