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FTP_lib.c
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FTP_lib.c
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#include "FTP_lib.h"
#include <sys/select.h>
#include <sys/times.h>
#define BUFLEN 1024
#define FILE_CHUNK 1000 /* how many bytes reading once */
//#define DEBUGMODE
/* *************************************
* CLIENT *
************************************* */
static int reads_firstb(conn_t* conn);
static int reads_ok(conn_t* conn);
static int reads_dim(conn_t* conn, uint32_t* dim);
static int reads_timestamp(conn_t* conn, uint32_t* time);
static int wait_for_event(int sock);
typedef struct TIMEOUT_HANDLER
{
fd_set fds; /* in this case we need only 1 type of events */
struct timeval timer;
} select_t;
static int setup(conn_t* conn)
{
conn->r_buf = NULL;
conn->s_buf = NULL;
conn->err_msg = NULL;
memset( &(conn->s_ip), 0, sizeof(conn->s_ip));
memset( &(conn->d_ip), 0, sizeof(conn->d_ip));
memset( &(conn->socket), 0, sizeof(conn->socket));
memset( &(conn->port), 0, sizeof(conn->port));
memset( &(conn->active), 0, sizeof(conn->port));
/* initialization of the err_msg */
if( (conn->err_msg = (char*) malloc(BUFLEN*sizeof(char))) == NULL )
return -1;
/* initialization for both r_buf and s_buf */
if( (conn->r_buf = (char*) malloc(BUFLEN*sizeof(char)) ) == NULL )
return -1;
if( (conn->s_buf = (char*) malloc(BUFLEN*sizeof(char)) ) == NULL )
return -1;
#ifdef DEBUGMODE
printf("Everything allocated successfully\n");
#endif
conn->active = 1; /* activates that connection */
memset(conn->s_buf, '\0', BUFLEN);
memset(conn->r_buf, '\0', BUFLEN);
memset(conn->err_msg, '\0', BUFLEN);
return 0;
}
/**
* connection function
*/
int connect_to(conn_t* conn, char* ip, char* port)
{
uint16_t portnum;
int result;
struct in_addr ipaddr;
struct sockaddr_in saddr;
/* initialize the memory for the connection data */
result = setup(conn);
if(result == -1) /* checking for mem error */
{
/* delete all the possible allocating data */
close_conn(conn);
return -1;
}
/* initialization for the socket */
conn->socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if(conn->socket < 0)
{
if(conn->err_msg != NULL)
strncpy(conn->err_msg, "Socket error", BUFLEN-1);
return -2;
}
/* processing the ip address string */
result = inet_aton(ip, &ipaddr); /* result used only for debug purpose */
conn->s_ip = ipaddr; /* the source is always local host for this version */
result = inet_aton(ip, &ipaddr);
if(result == 0)
{
if(conn->err_msg != NULL)
strncpy(conn->err_msg, "Invalid IP address", BUFLEN-1);
return -2;
}
conn->d_ip = ipaddr; /* in the network notation */
/* processing the port string */
if (sscanf(port, "%" SCNu16, &portnum)!=1)
{
if(conn->err_msg != NULL)
strncpy(conn->err_msg, "Invalid port number", BUFLEN-1);
return -2;
}
conn->port = htons(portnum); /* in network notation */
/* prepares the address structure */
bzero(&saddr, sizeof(saddr));
saddr.sin_family = AF_INET;
saddr.sin_port = conn->port;
saddr.sin_addr = ipaddr;
/* connect */
#ifdef DEBUGMODE
showAddr("Connecting to target address", &saddr);
#endif
result = connect(conn->socket, (struct sockaddr*) &saddr, sizeof(saddr));
if(result < 0)
{
if(conn->err_msg != NULL)
strncpy(conn->err_msg, "Connection error", BUFLEN-1);
return -2;
}
#ifdef DEBUGMODE
printf("done.\n");
#endif
return 0;
}
/**
* sends a get message to the connected host
*/
static int get_file(conn_t *conn, char* filename)
{
int wrtb;
memset(conn->err_msg, '\0', BUFLEN);
memset(conn->s_buf, '\0', BUFLEN);
/* composes the GET message for request */
sprintf(conn->s_buf, "GET %s\r\n", filename);
#ifdef DEBUGMODE
printf("Request message was ok : %s\n", conn->s_buf);
#endif
wrtb = writen(conn->socket, conn->s_buf, strlen(conn->s_buf));
if(wrtb < 0)
{
if(conn->err_msg != NULL)
strncpy(conn->err_msg, "Connection - error while sending GET request", BUFLEN-1);
return -1;
}
#ifdef DEBUGMODE
printf("GET sent successfully\n");
#endif
return 0;
}
int receive_file(conn_t* conn, char* filename, uint32_t* dim, uint32_t* timestamp)
{
int recvb,
result,
leftb;
FILE* desc;
memset(conn->err_msg, '\0', BUFLEN);
memset(conn->r_buf, '\0', BUFLEN);
/* it sends the get message for that file */
result = get_file(conn, filename);
if(result < 0)
return -1;
/*reads the first byte (+ or -) */
if(wait_for_event(conn->socket) == 0)
{
if(conn->err_msg != NULL)
strncpy(conn->err_msg, "timeout from client", BUFLEN-1);
return -1;
}
result = reads_firstb(conn); /* no select here beacause I have to wait for precedent client requests in case of sequential server */
if(result == -1) /* -ERR or out of protocol msg */
{
recvb = read(conn->socket, conn->r_buf, 5); /* not readn because it may be an out of protocol message (so it can be blocked) */
if(strcmp(conn->r_buf, "ERR\r\n") == 0 && conn->err_msg != NULL)
strncpy(conn->err_msg, "Error: -ERR message received!", BUFLEN-1);
else if(conn->err_msg != NULL)
strncpy(conn->err_msg, "Protocol - unknown message from server", BUFLEN-1);
return -2;
}
/* +OK message */
result = reads_ok(conn);
if(result == -1)
{
if(conn->err_msg != NULL)
strncpy(conn->err_msg, "Connection - error while receiving", BUFLEN-1);
return -1;
}
result = reads_dim(conn, dim);
if(result == -1)
{
if(conn->err_msg != NULL)
strncpy(conn->err_msg, "Error - invalid dimension", BUFLEN-1);
return -1;
}
result = reads_timestamp(conn, timestamp);
if(result == -1)
{
if(conn->err_msg != NULL)
strncpy(conn->err_msg, "Error - invalid timestamp", BUFLEN-1);
return -1;
}
desc = fopen(filename, "wb");
if(desc == NULL)
{
if(conn->err_msg != NULL)
strncpy(conn->err_msg, "Error - invalid timestamp", BUFLEN-1);
return -1;
}
result = flock(fileno(desc), LOCK_EX); //acquire the lock on that file
if(result < 0)
{
fclose(desc);
if(conn->err_msg != NULL)
strncpy(conn->err_msg, strerror(errno), BUFLEN-1);
return -1;
}
leftb = *dim;
if(*dim == 0)
{
flock(fileno(desc), LOCK_UN);
fclose(desc);
return 0; /* does not write anything on the file and returns */
}
recvb = -1; //initialization
do
{
if(recvb == 0) //no more data on the socket but file still miss
{
flock(fileno(desc), LOCK_UN);
fclose(desc);
if(conn->err_msg != NULL)
strncpy(conn->err_msg, "Connection - error while receiving", BUFLEN-1);
return -1;
}
memset(conn->r_buf, '\0', BUFLEN);
if(conn->r_buf == NULL) /* in case of closed and deallocated connection */
{
flock(fileno(desc), LOCK_UN);
fclose(desc);
return -1;
}
recvb = read(conn->socket, conn->r_buf, FILE_CHUNK);
if(recvb < 0 || strcmp(conn->r_buf, "-ERR\r\n") == 0)
{
flock(fileno(desc), LOCK_UN);
fclose(desc);
if(conn->err_msg != NULL)
strncpy(conn->err_msg, "Connection - error while receiving", BUFLEN-1);
return -1;
}
#ifdef DEBUGMODE
printf("%s\n", conn->r_buf);
#endif
if(recvb != 0)
fwrite(conn->r_buf, 1, recvb, desc);
leftb -= recvb;
} while(leftb > 0);
flock(fileno(desc), LOCK_UN);
fclose(desc);
return 0;
}
static int reads_firstb(conn_t* conn)
{
memset(conn->r_buf, '\0', BUFLEN);
int readb = read(conn->socket, conn->r_buf, 1);
#ifdef DEBUGMODE
printf("%s", conn->r_buf);
#endif
if(strcmp(conn->r_buf, "+") == 0)
return 0;
/* also in the case of out of protocol message */
return -1;
}
static int reads_ok(conn_t* conn)
{
memset(conn->r_buf, '\0', BUFLEN);
read(conn->socket, conn->r_buf, 4);
if(strcmp(conn->r_buf, "OK\r\n") == 0)
return 0;
/* also in the case of out of protocol message */
return -1;
}
static int reads_dim(conn_t* conn, uint32_t* dim)
{
uint32_t size;
memset(conn->r_buf, '\0', BUFLEN);
int readb = readn(conn->socket, &size, 4); /* readn because it cannot be less */
if(readb < 4)
return -1;
*dim = ntohl(size); /* from network byte order to host one */
#ifdef DEBUGMODE
printf("dim: %u\n", *dim);
#endif
return 0;
}
static int reads_timestamp(conn_t* conn, uint32_t* time)
{
uint32_t ts;
memset(conn->r_buf, '\0', BUFLEN);
int readb = readn(conn->socket, &ts, 4);
if(readb < 4)
return -1;
*time = ntohl(ts); /* from network byte order to host one */
#ifdef DEBUGMODE
printf("ts: %u\n", *time);
#endif
return 0;
}
/* Sends message for closing the connection */
int send_quit_msg(conn_t* conn)
{
int wrtb;
if(conn->s_buf == NULL) //deallocated structure
return -1;
memset(conn->s_buf, '\0', BUFLEN);
sprintf(conn->s_buf, "%s", "QUIT\r\n");
#ifdef DEBUGMODE
printf("QUIT message was ok : %s\n", conn->s_buf);
#endif
wrtb = writen(conn->socket, conn->s_buf, 6);
if(wrtb < 0)
{
if(conn->err_msg != NULL)
strncpy(conn->err_msg, "Connection - error while sending QUIT request", BUFLEN-1);
return -1;
}
#ifdef DEBUGMODE
printf("QUIT sent successfully\n");
#endif
return 0;
}
/**
* closes the connection
*/
void close_conn(conn_t* conn)
{
close(conn->socket);
free(conn->r_buf);
free(conn->s_buf);
free(conn->err_msg);
conn->r_buf = NULL;
conn->s_buf = NULL;
conn->err_msg = NULL;
#ifdef DEBUGMODE
printf("Deallocation ok\n");
#endif
}
char* strerr(conn_t connection)
{
if(connection.err_msg == NULL)
return "Host disconnected";
else
return connection.err_msg;
}
/* *************************************
* SERVER *
************************************* */
static int open_connection(server_t* server, struct in_addr dest, uint16_t cl_port, int sock, int* conn_id);
static int exists_conn(struct in_addr addr, uint16_t cl_port, conn_t* conns, int conn_n, int* conn_id);
static int is_off(server_t server);
static int is_in_err(server_t server);
static int search_available(server_t server);
static int is_path_allowed(const char* s);
int server_setup(server_t* server)
{
memset( &(server->stat_flag), 0, sizeof(server->stat_flag)); /* sets DOWN */
server->connections = NULL;
server->error = NULL;
memset( &(server->connections_n), 0, sizeof(server->connections_n));
server->error = (char*) malloc(BUFLEN * sizeof(char));
if(server->error == NULL)
{
server->stat_flag = server->stat_flag ^ 2; /* sets ERR */
return -1;
}
/* MAX_REQUEST_N + 1 because the first one is listen only */
server->connections = (conn_t*) malloc( (MAX_REQUEST_N+1) * sizeof(conn_t));
if(server->connections == NULL)
{
server->stat_flag = server->stat_flag ^ 2; /* sets ERR */
strncpy(server->error, "Unable to handle so many requests. Unsufficient memory", BUFLEN-1);
return -2;
}
server->stat_flag = server->stat_flag ^ 1; /* sets UP */
memset(server->error, '\0', BUFLEN);
memset(server->connections, 0, (MAX_REQUEST_N + 1) * sizeof(conn_t));
return 0;
}
/* listen on that port. It creates the first connection*/
int listen_on(server_t *server, char* port)
{
conn_t* conn = &(server->connections[0]);
uint16_t portnum;
int result;
struct in_addr ipaddr;
struct sockaddr_in my_addr;
if(is_off(*server))
{
strncpy(server->error, "The server is off. Please turn it on", BUFLEN-1);
return -1;
}
if(is_in_err(*server))
{
strncpy(server->error, "The server is in error", BUFLEN-1);
return -1;
}
/* initialize the memory for the listening conn */
result = setup(conn);
if(result == -1)
{
/* delete all the possible allocating data */
close_conn(conn);
strncpy(server->error, "Not enough memory", BUFLEN-1);
return -1;
}
if(server->connections_n < 1)
server->connections_n ++; /* at least one connections (the listening one) */
/* initialization for the socket */
conn->socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if(conn->socket < 0)
{
if(conn->err_msg != NULL)
strncpy(conn->err_msg, "Socket - error", BUFLEN-1);
return -2;
}
/* processing the port string */
if (sscanf(port, "%" SCNu16, &portnum)!=1)
{
if(conn->err_msg != NULL)
strncpy(conn->err_msg, "Invalid port number", BUFLEN-1);
return -2;
}
server->list_port = htons(portnum); /* in network notation */
/* For the server we know only the source ip actually
* (the dest ip will be available after the accept())
* result used only for debug purpose */
result = inet_aton("0.0.0.0", &ipaddr);
conn->s_ip = ipaddr;
/* bind the socket to localhost only */
bzero(&my_addr, sizeof(my_addr));
my_addr.sin_family = AF_INET;
my_addr.sin_port = server->list_port;
my_addr.sin_addr.s_addr = INADDR_ANY;
#ifdef DEBUGMODE
showAddr("Binding to address", &my_addr);
#endif
result = bind(conn->socket, (struct sockaddr *) &my_addr, sizeof(my_addr));
if(result < 0)
{
if(conn->err_msg != NULL)
strncpy(conn->err_msg, strerror(errno), (BUFLEN-1) * sizeof(char));
return -1;
}
#ifdef DEBUGMODE
printf("done.\n");
#endif
/* starts to listen on that socket and define the max # of pending requests on that socket queue */
result = listen(conn->socket, MAX_PENDING_REQUEST);
if(result < 0)
{
if(conn->err_msg != NULL)
strncpy(conn->err_msg, strerror(errno), BUFLEN-1);
return -1;
}
return 0;
}
/* done by the first conn_t ( connections[0] )*/
int accept_new_request(server_t* server, int* conn_id)
{
int result,
new_sock;
conn_t* listening_conn = &(server->connections[0]);
struct sockaddr_in client_addr;
socklen_t client_l;
bzero(&client_addr, sizeof(client_addr));
client_l = sizeof(struct sockaddr_in);
/* accept returns the new socket copy of the previous one */
new_sock = accept(listening_conn->socket, (struct sockaddr*) &client_addr, &client_l);
if(new_sock < 0)
{
if(listening_conn->err_msg != NULL)
{
strncpy(listening_conn->err_msg, strerror(errno), BUFLEN-1);
strncat(listening_conn->err_msg, " (accept() error)", BUFLEN-1);
}
*conn_id = 0; /* listening connection */
return -1;
}
/* searching for an already existing connection with that host */
if(exists_conn(client_addr.sin_addr, client_addr.sin_port, server->connections, server->connections_n, conn_id))
{
server->connections[*conn_id].socket = new_sock; /* update the socket */
return 0; /* conn_id already setted by previous function */
}
else
{
if(server->connections_n < (MAX_REQUEST_N + 1) ) /* the first one is listening only */
{
result = open_connection(server, client_addr.sin_addr, client_addr.sin_port, new_sock, conn_id);
if(result < 0)
{
if(listening_conn->err_msg != NULL)
strncpy(listening_conn->err_msg, "Memory problem", BUFLEN-1);
*conn_id = 0;
return -1;
}
return 0;
}
else
{
if(listening_conn->err_msg != NULL)
strncpy(listening_conn->err_msg, "Maximum #of requests reached. Impossible to handle another one", BUFLEN-1);
return -1;
}
}
}
int serve_request(conn_t* conn, char* fname)
{
int readb;
uint32_t result;
memset(conn->err_msg, '\0', BUFLEN);
memset(conn->r_buf, '\0', BUFLEN);
memset(fname, '\0', MAX_FILE_NAME);
readb = read(conn->socket, conn->r_buf, 4); /* read is better for detecting out of protocol message */
if(readb == -1)
{
if(conn->err_msg != NULL)
strncpy(conn->err_msg, strerror(errno), BUFLEN-1);
return -1;
}
if(readb < 4)
{
if(conn->err_msg != NULL)
strncpy(conn->err_msg, "unknown message", BUFLEN-1);
return -1;
}
#ifdef DEBUGMODE
printf("%s", conn->r_buf);
#endif
if( strcmp(conn->r_buf, "GET ") == 0)
{
memset(conn->r_buf, '\0', BUFLEN); /* cleaning */
if(wait_for_event(conn->socket) == 0)
{
if(conn->err_msg != NULL)
strncpy(conn->err_msg, "timeout from server", BUFLEN-1);
return -1;
}
readb = read(conn->socket, conn->r_buf, MAX_FILE_NAME + 2); /* read because I don't know the exact filename length */
#ifdef DEBUGMODE
printf("%s", conn->r_buf);
#endif
if(conn->r_buf[readb - 2] == '\r' && conn->r_buf[readb - 1] == '\n')
{ /*presence of QUIT after GET due to client timeout*/
if(readb >= 8 && conn->r_buf[readb-7] == '\n' && conn->r_buf[readb-8] == '\r')
{
if(conn->err_msg != NULL)
strncpy(conn->err_msg, "QUIT message received", BUFLEN-1);
return 1; /* returns the QUIT*/
}
strncpy(fname, conn->r_buf, readb - 2);
if(is_path_allowed(fname))
return 0;
else
{
if(conn->err_msg != NULL)
strncpy(conn->err_msg, "Path out of server file system", BUFLEN-1);
return -1;
}
}
else
{
if(conn->err_msg != NULL)
strncpy(conn->err_msg, "unknown message", BUFLEN-1);
return -1;
}
}
else
if( strcmp(conn->r_buf, "QUIT") == 0)
{
memset(conn->r_buf, '\0', BUFLEN); /* cleaning */
readb = readn(conn->socket, conn->r_buf, 2); /* reads \r\n */
if(readb != 2 || strcmp(conn->r_buf, "\r\n") != 0)
{
if(conn->err_msg != NULL)
strncpy(conn->err_msg, "unknown message", BUFLEN-1);
return -1;
}
return 1; /* QUIT message */
}
else
return -1;
}
static int is_path_allowed(const char* s)
{
if(!s || (s[0] == '~' || s[0] == '/'))
return 0;
if(strstr(s, ".."))
return 0;
return 1;
}
int send_err_msg(conn_t* conn)
{
int recvb;
if(conn->s_buf == NULL) //deallocated structure
return -1;
memset(conn->s_buf, '\0', BUFLEN);
strncpy(conn->s_buf, "-ERR\r\n", BUFLEN-1);
recvb = writen(conn->socket, conn->s_buf, strlen(conn->s_buf));
if(recvb < 6)
{
if(conn->err_msg != NULL)
strncpy(conn->err_msg, "Uncomplete message was sent", BUFLEN-1);
return -1;
}
return 0;
}
int transmit_file(conn_t* conn, char* filename)
{
int recvb,
timestamp,
readb,
result;
FILE* fptr;
uint32_t size;
struct stat st;
fptr = fopen(filename, "rb");
if(fptr == NULL)
{
if(conn->err_msg != NULL)
strncpy(conn->err_msg, "Unable to locate the file", BUFLEN-1);
return -1;
}
result = flock(fileno(fptr), LOCK_EX);
if(result < 0)
{
fclose(fptr);
fptr = NULL;
if(conn->err_msg != NULL)
strncpy(conn->err_msg, strerror(errno), BUFLEN-1);
return -1;
}
memset(conn->s_buf, '\0', BUFLEN);
// writes +OK\r\n
strncpy(conn->s_buf, "+OK\r\n", BUFLEN-1);
recvb = writen(conn->socket, conn->s_buf, strlen(conn->s_buf));
// writes dimension on 4 bytes
stat(filename, &st);
size = (uint32_t) st.st_size; //off_t not well defined. Not easy to check if 32bits are enough
size = htonl(size);
recvb = writen(conn->socket, &size, 4);
if(recvb == -1)
{
flock(fileno(fptr), LOCK_UN);
fclose(fptr);
fptr = NULL;
if(conn->err_msg != NULL)
strncpy(conn->err_msg, "Problem when sending", BUFLEN-1);
return -1;
}
//writes timestamp on 4 bytes
timestamp = (int) st.st_mtime;
timestamp = htonl(timestamp);
recvb = writen(conn->socket, ×tamp, 4);
if(recvb == -1)
{
flock(fileno(fptr), LOCK_UN);
fclose(fptr);
fptr = NULL;
if(conn->err_msg != NULL)
strncpy(conn->err_msg, "Problem when sending", BUFLEN-1);
return -1;
}
//sends the file
size_t sentdim = 0;
size_t readdim = 0;
while(1)
{
memset(conn->s_buf, '\0', BUFLEN);
readb = fread(conn->s_buf, 1, FILE_CHUNK, fptr);
if(readb == 0)
break; /* EOF */
recvb = writen(conn->socket, conn->s_buf, readb * sizeof(char));
if(recvb < readb)
{
flock(fileno(fptr), LOCK_UN);
fclose(fptr);
fptr = NULL;
if(conn->err_msg != NULL)
strncpy(conn->err_msg, "File transmit error", BUFLEN-1);
return -1;
}
readdim += readb;
sentdim += recvb;
}
flock(fileno(fptr), LOCK_UN);
fclose(fptr);
fptr = NULL;
return 0;
}
/* open a new connection with a specified host */
static int open_connection(server_t* server, struct in_addr dest, uint16_t cl_port, int sock, int* conn_id)
{
int result;
/* searches for the first available connection spot */
*conn_id = search_available(*server);
/* setup memory for buffers */
result = setup( &(server->connections[*conn_id]) ) ;
server->connections_n ++;
if(result < 0)
{
/* delete all the possible allocating data */
close_conn( &(server->connections[*conn_id]) );
return -1;
}
server->connections[*conn_id].s_ip = server->connections[0].s_ip;
server->connections[*conn_id].d_ip = dest;
server->connections[*conn_id].port = cl_port;
server->connections[*conn_id].socket = sock;
return 0;
}
static int search_available(server_t server)
{
int i;
/* do not consider the listening conn[0] */
for(i = 1; server.connections[i].active == 0 && i < MAX_REQUEST_N; i++);
return i;
}
/* it searches for a connection matching address addr and sets
*correspondingly the conn_id */
static int exists_conn(struct in_addr addr, uint16_t cl_port, conn_t* conns, int conn_n, int* conn_id)
{
int count;
/* the first connection is listen only so count starts from 1 */
for(count = 1; count < conn_n; count ++)
{ /* conns[count].d_ip.s_addr can be 0 if this connection position was closed */
if(conns[count].d_ip.s_addr != 0 && addr.s_addr == conns[count].d_ip.s_addr && conns[count].port == cl_port)
{
*conn_id = count;
return 1;
}
}
return 0; /* not found */
}
/* returns 1 if server is down */
static int is_off(server_t server)
{
return !(server.stat_flag & 1);
}
/* returns 1 if server is in error */
static int is_in_err(server_t server)
{
return (server.stat_flag & 2);
}
/* returns the actual state of the server */
uint8_t intstat(server_t server)
{
if( (server.stat_flag ^ 2) >= 2) /* in ERR */
return 2;
else
return (server.stat_flag ^ 1); /* ON or OFF */
}
int wait_for_event(int sock)
{
select_t time_wrapper;
FD_ZERO(&time_wrapper.fds);
FD_SET(sock, &time_wrapper.fds);
time_wrapper.timer.tv_sec = TIMEOUT_SEC;
time_wrapper.timer.tv_usec = 0;
return select(sock+1, &time_wrapper.fds, NULL, NULL, &time_wrapper.timer);
}
/* it does not deallocate the conn_id instance, it simply clear that position because of reusing
another possible approach is to use a list for connections (inefficient for connections retrieving) */
void server_close_conn(server_t* server, int conn_id)
{
/* the user is not allowed to close the listening connection
* or to close something already closed, otherwise the #connections
* will be wrong
*/
if(conn_id == 0 || (conn_id+1) > server->connections_n)
return;
close_conn( &(server->connections[conn_id])); /* it performs the free and sets to null */
server->connections_n --;
}
void shut_down(server_t* server)
{
int count;
for(count = 0; count < server->connections_n; count ++)
close_conn(&(server->connections[count]));
free(server->connections);
server->connections_n = 0;
free(server->error);
/* shutdown the server */
memset( &(server->stat_flag), 0, sizeof(server->stat_flag));
#ifdef DEBUGMODE
printf("Server shutting down was ok\n");
#endif
server->connections = NULL;
server->error = NULL;
}