Function for reading files

readfile.c

char *readFile(const char *filepath) {
    char *source = NULL;
    FILE *fp = fopen(filepath, "r");
    if (fp) {
        if (fseek(fp, 0L, SEEK_END) == 0) {
            long bufsize = ftell(fp);
            source = malloc(sizeof(char) * (bufsize + 1));
            fseek(fp, 0L, SEEK_SET);

            size_t len = fread(source, sizeof(char), bufsize, fp);
            source[len++] = '\0';
        }
        fclose(fp);
    }
    return source;
}