libnnfs_msg_builder.c

#include "libnnfs_msg_builder.h"
#include "nnfs_constants.h"
#include "libnnfs_proto.h"

#include <stdio.h>
#include <string.h>
#include <stddef.h>

//defines a basic template call
void inner_build_template_call(struct MSG *message, uint32_t ID){
    message->header.type = TYPE_CALL;
    message->header.ID = ID;
    message->header.op_code = NULL_OP_CODE;
    message->header.payload_len = 0u;
    message->header.is_last = 1;
    message->header.number_in_sequence = 0;
    message->payload = NULL;
}

//defines a basic template reply
void inner_build_template_reply(struct MSG *message, uint32_t ID){
    message->header.type = TYPE_REPLY;
    message->header.ID = ID;
    message->header.op_code = NULL_OP_CODE;
    message->header.payload_len = 0u;
    message->header.is_last = 1;
    message->header.number_in_sequence = 0;
    message->payload = NULL;
}


void build_connect_call(struct MSG *message, uint32_t ID){
    destroy_msg(message);
    inner_build_template_call(message, ID);
    message->header.op_code = OP_CODE_CONNECT_CALL;
}

void build_success_reply(struct MSG *retval, uint32_t ID){
    destroy_msg(retval);
    inner_build_template_reply(retval, ID);
    retval->header.op_code = STATUS_SUCCESS;
}

void build_template_reply(struct MSG *retval, uint32_t ID, uint32_t reason, uint32_t length, unsigned char *payload, char last_message, char seq_number){
    destroy_msg(retval);
    inner_build_template_reply(retval, ID);
    retval->header.op_code = reason;
    retval->header.payload_len = length;
    retval->header.is_last = last_message;
    retval->header.number_in_sequence = seq_number;
    if(length == 0)
        retval->payload = NULL;
    else{
        retval->payload = calloc(length, 1);
        if(retval->payload == NULL){
            printf("ERROR: calloc returned NULL in build_fail_reply\n");
            exit(1);
        }
        strncpy((char*)retval->payload, (char *)payload, length);
    }
}
void build_quit_call(struct MSG *retval, uint32_t ID){
    destroy_msg(retval);
    inner_build_template_call(retval, ID);
    retval->header.op_code = OP_CODE_CLOSE_CONNECTION;
}

void build_ping_call(struct MSG *retval){
    destroy_msg(retval);
    inner_build_template_call(retval, 0);
    retval->header.op_code = OP_CODE_PING;
}


void build_pong_reply(struct MSG *retval){
    destroy_msg(retval);
    inner_build_template_reply(retval, 0);
    retval->header.op_code = STATUS_PONG;
}

void build_ls_call(struct MSG *message, uint32_t ID){
    destroy_msg(message);
    inner_build_template_call(message, ID);
    message->header.op_code = OP_CODE_LIST_DIRECTORY;
}

void build_chdir_call(struct MSG *message, uint32_t ID, const char *path){
    destroy_msg(message);
    inner_build_template_call(message, ID);
    message->header.op_code = OP_CODE_CHANGE_DIRECTORY;
    int length = message->header.payload_len = strlen(path);
    if(length == 0){
        printf("ERROR: empty path\n");
    }
    message->payload = calloc(1, length);
    if(message->payload == NULL){
        printf("ERROR: calloc returned NULL in build_fail_reply\n");
        exit(1);
    }
    strncpy((char*)message->payload, (char *)path, length);
}


void build_read_file_call(struct MSG *message, uint32_t ID, const char *filename, uint32_t number_of_characters, uint32_t offset, uint32_t read_mode){
    destroy_msg(message);
    inner_build_template_call(message, 0);

    message->header.op_code = OP_CODE_READ_FROM_REMOTE;

    char * payl = calloc(1, NNFS_MSG_MAX_LENGTH + 1);
    snprintf(payl, NNFS_MSG_MAX_LENGTH, READ_CALL_FORMAT, read_mode, offset, number_of_characters, filename);
    message->header.payload_len = strlen(payl);
    message->payload = calloc(1, message->header.payload_len);
    strncpy((char*)message->payload, (char *)payl, message->header.payload_len);
    free(payl);
}

void build_write_file_call(struct MSG *message, uint32_t ID, const char *filename, const char *to_write){
    destroy_msg(message);
    inner_build_template_call(message, 0);

    int length = sizeof(WRITE_CALL_FORMAT) + strlen(to_write) + strlen(filename) - 4;

    if(length > NNFS_MSG_MAX_LENGTH)
        return;
    
    message->header.op_code = OP_CODE_WRITE_FROM_LOCAL;

    char * payl = calloc(1, NNFS_MSG_MAX_LENGTH + 1);
    snprintf(payl, NNFS_MSG_MAX_LENGTH, WRITE_CALL_FORMAT, filename, to_write);
    message->header.payload_len = strlen(payl);
    message->payload = calloc(1, message->header.payload_len);
    strncpy((char*)message->payload, (char *)payl, message->header.payload_len);
    free(payl);
}