make a https get request in linux based on openssl - c

Question

guys.
I want to create a https get request on linux with openssl. I made the code from google and my mind. after i run the code,there is something happened, i think the RecvPacket() function has problem,but i do not know how to fix, please tell me how to fix it.
the website where i want to get is https://git.20202060.xyz.it just has a jpg file,what i want to do is download the picture to local file,but now i even can not get the https response,the i could not cut the picture out.
here is code.
SSL *ssl;
int sock;
int RecvPacket()
{
int len = 1024;
char buf[100000] = {'\0'};
if (SSL_read(ssl, buf, 1024) > 0)
{
printf("Receiving . . . .\n");
while (len = 1024)
{
// len = SSL_read(ssl, buf, 1024);
len = SSL_read(ssl, buf, 1024);
buf[len] = '\0';
printf("%s", buf);
if (len < 0)
{
break;
}
}
}
if (len < 0)
{
int err = SSL_get_error(ssl, len);
if (err == SSL_ERROR_WANT_READ)
return 0;
if (err == SSL_ERROR_WANT_WRITE)
return 0;
if (err == SSL_ERROR_ZERO_RETURN || err == SSL_ERROR_SYSCALL || err == SSL_ERROR_SSL)
return -1;
}
}
int SendPacket(const char *buf)
{
int len = SSL_write(ssl, buf, sizeof(buf));
if (len > 0)
{
fprintf(stderr, "Writing . . . . \n");
}
if (len < 0)
{
int err = SSL_get_error(ssl, len);
switch (err)
{
case SSL_ERROR_WANT_WRITE:
printf("SSL_ERROR_WANT_WRITE\n");
return 0;
case SSL_ERROR_WANT_READ:
printf("SSL_ERROR_WANT_READ\n");
return 0;
case SSL_ERROR_ZERO_RETURN:
printf("SSL_ERROR_ZERO_RETURN\n");
case SSL_ERROR_SYSCALL:
printf("SSL_ERROR_SYSCALL\n");
case SSL_ERROR_SSL:
printf("SSL_ERROR_SSL\n");
default:
return -1;
}
}
}
int main(int argc, char *argv[])
{
int sockfd;
sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (sockfd < 0)
{
printf("Error creating socket.\n");
return -1;
}
struct sockaddr_in sa;
memset(&sa, 0, sizeof(sa));
sa.sin_family = AF_INET;
sa.sin_addr.s_addr = inet_addr("119.28.113.108"); // address of 20202060.xyz
sa.sin_port = htons(443);
socklen_t socklen = sizeof(sa);
if (connect(sockfd, (struct sockaddr *)&sa, socklen))
{
printf("Error connecting to server.\n");
return -1;
}
//openssl initialize
SSL_library_init();
SSLeay_add_ssl_algorithms();
SSL_load_error_strings();
SSL_CTX *ctx = SSL_CTX_new(SSLv23_client_method());
ssl = SSL_new(ctx);
if (!ssl)
{
printf("Error creating SSL.\n");
log_ssl();
return -1;
}
//creat an ssl connection and attach it to the socket
sock = SSL_get_fd(ssl);
SSL_set_fd(ssl, sockfd);
SSL_set_connect_state(ssl);
int err = SSL_connect(ssl);
if (err != 1)
{
printf("Error creating SSL connection. err=%x\n", err);
log_ssl();
fflush(stdout);
return -1;
}
printf("SSL connection using %s\n", SSL_get_cipher(ssl));
char request[1024] = {'\0'};
// char *request_test = "Get /dog.jpg HTTP/1.1\r\nUser-Agent: Mozilla/4.0 (compatible; MSIE5.01; Windows NT)\r\nHost:https://20202060.xyz\r\nConnection: Close\r\n";
char host[100] = "https://git.20202060.xyz";
// char ip[30] = "119.28.113.108";
sprintf(request,
"GET /dog.jpg HTTP/1.1\r\n"
"Host: %s\r\n"
"Accept: */*\r\n"
"User-Agent:Mozilla/5.0\r\n"
"Connection: Close\r\n",
host);
SendPacket(request);
RecvPacket();
SSL_shutdown(ssl);
SSL_free(ssl);
close(sockfd);
return 0;
}