jeena/moxanix
1
0
Fork 0
Code Issues Pull requests Projects Packages Wiki Activity Actions

handling new clients in a separate thread

Browse source
This commit is contained in:
Igor Socec 2014-04-06 18:34:56 +02:00
parent 86f0bc612f
commit 604665ee05
4 changed files with 99 additions and 95 deletions
Download patch file Download diff file Expand all files Collapse all files

11
client.c
View file

@ -86,32 +86,31 @@ int client_write(struct client_t *client, char *databuf, int datalen) {
/* Waits for client input in "line mode". Blocks until input arrives. */ /* Waits for client input in "line mode". Blocks until input arrives. */
int client_wait_line(struct client_t *client) { int client_wait_line(struct client_t *client) {
int ret;
fd_set read_fds; fd_set read_fds;
struct timeval tv;
client->data[0] = '\0'; client->data[0] = '\0';
/* loop waiting for client input */ /* loop waiting for client input */
while (client->data[0] == '\0') { while (client->data[0] == '\0') {
/* setup select() parameters */ /* setup select() parameters */
tv.tv_sec = 15; /* 15 second timeout */
tv.tv_usec = 0;
FD_ZERO(&read_fds); FD_ZERO(&read_fds);
FD_SET(client->socket, &read_fds); FD_SET(client->socket, &read_fds);
/* send prompt character to client */ /* send prompt character to client */
client_write(client, "> ", 2); client_write(client, "> ", 2);
/* block until input arrives */ /* block until input arrives */
if (select((client->socket)+1, &read_fds, NULL, NULL, NULL) == -1) return -1; if (select((client->socket)+1, &read_fds, NULL, NULL, &tv) <= 0) return -1;
if (FD_ISSET(client->socket, &read_fds)) { if (FD_ISSET(client->socket, &read_fds)) {
/* read client input */ /* read client input */
ret = client_read(client); if (client_read(client) == -1) return -1;
if (ret == -1) return -1;
/* we don't want empty data so stop on \r or \n */ /* we don't want empty data so stop on \r or \n */
if ( (client->data[0] == '\r') || (client->data[0] == '\n') ) { if ( (client->data[0] == '\r') || (client->data[0] == '\n') ) {
fprintf(stderr, "client data is empty\n");
client->data[0] = '\0'; client->data[0] = '\0';
} }
} }
} }
fprintf(stderr, "client data: %s\n", client->data);
return 0; return 0;
} }

65
moxerver.c
View file

@ -11,7 +11,7 @@
#define NAME "moxerver" #define NAME "moxerver"
#define SERVER_WAIT_TIMEOUT 5 /* seconds for select() timeout in server loop */ #define SERVER_WAIT_TIMEOUT 2 /* seconds for select() timeout in server loop */
/* Prints help message. */ /* Prints help message. */
static void usage() { static void usage() {
@ -82,15 +82,14 @@ int main(int argc, char *argv[]) {
int fdmax; int fdmax;
struct timeval tv; struct timeval tv;
pthread_t tty_thread; pthread_t tty_thread, new_client_thread;
/* zero init tty_dev */ /* zero init tty_dev */
if (cfsetispeed(&(tty_dev.ttyset), B0) < 0 || if (cfsetispeed(&(tty_dev.ttyset), B0) < 0 ||
cfsetospeed(&(tty_dev.ttyset), B0) < 0) { cfsetospeed(&(tty_dev.ttyset), B0) < 0) {
fprintf(stderr, "[%s] error configuring tty device speed\n", NAME); fprintf(stderr, "[%s] error configuring tty device speed\n", NAME);
return -1; return -1;
} }
/* enable catching and handling some quit signals, SIGKILL can't be caught */ /* enable catching and handling some quit signals, SIGKILL can't be caught */
signal(SIGTERM, quit_handler); signal(SIGTERM, quit_handler);
@ -141,6 +140,7 @@ int main(int argc, char *argv[]) {
/* initialize */ /* initialize */
if (server_setup(&server, tcp_port) < 0) return -1; if (server_setup(&server, tcp_port) < 0) return -1;
client.socket = -1; client.socket = -1;
new_client.socket = -1;
tty_dev.fd = -1; tty_dev.fd = -1;
/* parse config file if any */ /* parse config file if any */
@ -150,7 +150,7 @@ int main(int argc, char *argv[]) {
return -1; return -1;
} }
else if (!def_conf && ret) { else if (!def_conf && ret) {
fprintf(stderr, "[%s] error parsing congig file %s on line %d\n", NAME, CONFILE, ret); fprintf(stderr, "[%s] error parsing config file %s on line %d\n", NAME, CONFILE, ret);
return -1; return -1;
} }
@ -177,9 +177,25 @@ int main(int argc, char *argv[]) {
return -1; return -1;
} }
/* loop with timeouts waiting for client connection and data */ /* loop with timeouts waiting for client connection requests and data */
while (1) { while (1) {
/* check if new client is availabe for connection */
if ( (client.socket == -1) && (new_client.socket != -1) ) {
/* copy new client information */
memcpy(&client, &new_client, sizeof(struct client_t));
new_client.socket = -1;
fprintf(stderr, "[%s] client %s connected\n", NAME, client.ip_string);
/* ask client to provide a username before going to "character" mode */
if (client_ask_username(&client) != 0) {
/* close client if not able to provide a username */
client_close(&client);
continue;
}
/* put client in "character" mode */
telnet_set_character_mode(&client);
}
/* setup parameters for select() */ /* setup parameters for select() */
tv.tv_sec = SERVER_WAIT_TIMEOUT; tv.tv_sec = SERVER_WAIT_TIMEOUT;
tv.tv_usec = 0; tv.tv_usec = 0;
@ -188,7 +204,7 @@ int main(int argc, char *argv[]) {
if (client.socket != -1) { if (client.socket != -1) {
FD_SET(client.socket, &read_fds); /* wait for client if connected */ FD_SET(client.socket, &read_fds); /* wait for client if connected */
} }
fdmax = (server.socket > client.socket) ? server.socket : client.socket; fdmax = (server.socket > client.socket) ? server.socket : client.socket;
/* wait with select() */ /* wait with select() */
ret = select(fdmax+1, &read_fds, NULL, NULL, &tv); ret = select(fdmax+1, &read_fds, NULL, NULL, &tv);
@ -201,36 +217,11 @@ int main(int argc, char *argv[]) {
/* check server status */ /* check server status */
if (FD_ISSET(server.socket, &read_fds)) { if (FD_ISSET(server.socket, &read_fds)) {
fprintf(stderr, "[%s] received client connection request\n", NAME); fprintf(stderr, "[%s] received client connection request\n", NAME);
/* accept connection request if no client is connected */ /* handle new client connection request in a separate thread */
if (client.socket == -1) { if (pthread_create(&new_client_thread, NULL, server_new_client_thread, NULL) != 0) {
ret = server_accept(&server, &client); /* print error but continue waiting for connection request */
if ( ret != 0) { fprintf(stderr, "[%s] problem with handling client connection request\n", NAME);
/* print error but continue waiting for connection request */ continue;
//TODO maybe we should break here to avoid endless loop, what are possible causes of this failure?
fprintf(stderr, "[%s] problem accepting client\n", NAME);
continue;
}
/* ask client to provide a username before going to "character" mode */
client_ask_username(&client);
/* put client in "character" mode */
telnet_set_character_mode(&client);
}
/* if a client is already connected then new clients need to be handled */
else {
/* decide if current client needs to be dropped or new client needs to be rejected */
ret = server_drop(&server, &client);
if (ret < 0) {
/* error in handling new clients, print but continue waiting for new clients */
fprintf(stderr, "[%s] problem handling new client request\n", NAME);
continue;
}
/* if current client was dropped we need to set up new client */
if (ret > 0) {
/* ask client to provide a username before going to "character" mode */
client_ask_username(&client);
/* put client in "character" mode */
telnet_set_character_mode(&client);
}
} }
} }
/* check client status if connected */ /* check client status if connected */

45
moxerver.h
View file

@ -21,34 +21,35 @@
/* Structures used for communication parameters. */ /* Structures used for communication parameters. */
struct server_t { struct server_t {
int socket; /* server socket */ int socket; /* server socket */
struct sockaddr_in address; /* server address information */ struct sockaddr_in address; /* server address information */
unsigned int port; /* server port in host byte order, practical reference */ unsigned int port; /* server port in host byte order, practical reference */
}; };
struct client_t { struct client_t {
int socket; /* client socket */ int socket; /* client socket */
struct sockaddr_in address; /* client address information */ struct sockaddr_in address; /* client address information */
char ip_string[INET_ADDRSTRLEN]; /* client IP address as a string */ char ip_string[INET_ADDRSTRLEN]; /* client IP address as a string */
time_t last_active; /* time of client's last activity in seconds from Epoch */ time_t last_active; /* time of client's last activity in seconds from Epoch */
char username[USERNAME_LEN]; /* username for human identification */ char username[USERNAME_LEN]; /* username for human identification */
char data[DATABUF_LEN]; /* buffer for data received from client */ char data[DATABUF_LEN]; /* buffer for data received from client */
}; };
struct tty_t { struct tty_t {
int fd; /* tty file descriptor */ int fd; /* tty file descriptor */
struct termios ttysetdef; /* default tty termios settings */ struct termios ttysetdef; /* default tty termios settings */
struct termios ttyset; /* tty termios settings */ struct termios ttyset; /* tty termios settings */
char path[DEV_PATH]; /* tty device path */ char path[DEV_PATH]; /* tty device path */
char data[DATABUF_LEN]; /* buffer for data received from tty */ char data[DATABUF_LEN]; /* buffer for data received from tty */
}; };
/* Global variables used throughout the application. */ /* Global variables used throughout the application. */
int debug_messages; /* if > 0 debug messages will be printed */ int debug_messages; /* if > 0 debug messages will be printed */
struct server_t server; /* main server structure */ struct server_t server; /* main server structure */
struct client_t client; /* connected client structure */ //TODO working with only 1 client, this can be expanded into a list struct client_t client; /* connected client structure */ //TODO working with only 1 client, this can be expanded into a list
struct tty_t tty_dev; /* connected tty device */ struct client_t new_client; /* client structure for new client request */
struct tty_t tty_dev; /* connected tty device */
/* Global functions used throughout the application. */ /* Global functions used throughout the application. */
@ -91,15 +92,17 @@ int server_close(struct server_t *server);
int server_accept(struct server_t *server, struct client_t *accepted_client); int server_accept(struct server_t *server, struct client_t *accepted_client);
/** /**
* Asks new incoming client connection if current client needs to be dropped. * Thread function handling new client connections.
* If current client doesn't need to be dropped then new client is rejected. * If there is no connected client then first client request is accepted.
* If there is a connected client then new client is asked if connected client should be dropped.
* *
* Returns: * Returns:
* - positive value if current client was dropped * Return value from this thread function is not used.
* - 0 if new client was rejected * Function handles global client variables:
* - negative value if error occurred * - client structure is reset if new client is available to connect to
* - new_client structure stores information about the client to connect to
*/ */
int server_drop(struct server_t *server, struct client_t *client); void* server_new_client_thread(void *args);
/* Functions handling communication with clients. */ /* Functions handling communication with clients. */

73
server.c
View file

@ -47,8 +47,8 @@ int server_setup(struct server_t *server, unsigned int port) {
server->port = port; server->port = port;
fprintf(stderr,"[%s] assigned port %u\n", __func__, server->port); //ntohs(server->address.sin_port) fprintf(stderr,"[%s] assigned port %u\n", __func__, server->port); //ntohs(server->address.sin_port)
/* listen for a client connection, allow 2 connections in queue */ /* listen for a client connection, allow some connections in queue */
if (listen(server->socket, 2) == -1) { if (listen(server->socket, 1) == -1) {
fprintf(stderr, "[%s:%d] error %d: %s\n", __func__, __LINE__, errno, strerror(errno)); fprintf(stderr, "[%s:%d] error %d: %s\n", __func__, __LINE__, errno, strerror(errno));
return -errno; return -errno;
} }
@ -98,58 +98,69 @@ int server_accept(struct server_t *server, struct client_t *accepted_client) {
/* print client information */ /* print client information */
time2string(accepted_client->last_active, timestamp); time2string(accepted_client->last_active, timestamp);
fprintf(stderr, "[%s] accepted client %s on port %u @ %s\n", __func__, fprintf(stderr, "[%s] accepted client %s @ %s\n",
accepted_client->ip_string, server->port, timestamp); __func__, accepted_client->ip_string, timestamp);
return 0; return 0;
} }
/* Drops current client or rejects new client. */ /* Thread function handling new client connections. Handles global client variables. */
int server_drop(struct server_t *server, struct client_t *current_client) { void* server_new_client_thread(void *args) {
struct client_t new_client;
char msg[DATABUF_LEN]; char msg[DATABUF_LEN];
char timestamp[TIMESTAMP_LEN]; char timestamp[TIMESTAMP_LEN];
struct client_t temp_client;
/* accept new connection request */ /* accept new connection request */
if (server_accept(server, &new_client) != 0) return -1; if (server_accept(&server, &temp_client) != 0) return (void *) -1;
/* if no client is connected then make new client available for connection */
if (client.socket == -1) {
memcpy(&new_client, &temp_client, sizeof(struct client_t));
return (void *) 0;
}
/* if there is already a new client being handled then reject this client request */
if (new_client.socket != -1) {
sprintf(msg, "\nToo many connection requests, please try later.\n");
send(temp_client.socket, msg, strlen(msg), 0);
client_close(&temp_client);
time2string(time(NULL), timestamp);
fprintf(stderr, "[%s] rejected new client request %s @ %s\n",
__func__, temp_client.ip_string, timestamp);
return (void *) 0;
}
/* make new client available for connection */
memcpy(&new_client, &temp_client, sizeof(struct client_t));
/* inform new client that port is already in use */ /* inform new client that port is already in use */
time2string(current_client->last_active, timestamp); time2string(client.last_active, timestamp);
sprintf(msg, "\nPort %u is already being used!\nCurrent user and last activity:\n%s @ %s\n", sprintf(msg, "\nPort %u is already being used!\nCurrent user and last activity:\n%s @ %s\n",
server->port, current_client->username, timestamp); server.port, client.username, timestamp);
send(new_client.socket, msg, strlen(msg), 0); send(new_client.socket, msg, strlen(msg), 0);
/* ask new client if current client should be dropped */ /* ask new client if current client should be dropped */
sprintf(msg, "\nDo you want to drop the current user?\nIf yes then please type YES DROP (in uppercase):"); sprintf(msg, "\nDo you want to drop the current user?\nIf yes then please type YES DROP (in uppercase):\n");
send(new_client.socket, msg, strlen(msg), 0); send(new_client.socket, msg, strlen(msg), 0);
/* wait for client input */ /* wait for client input */
if (client_wait_line(&new_client) != 0) return -1; client_wait_line(&new_client);
/* check client confirmation */ /* check client confirmation */
if (strncmp(new_client.data, "YES DROP", 8) == 0) { if (strncmp(new_client.data, "YES DROP", 8) == 0) {
/* current client should be dropped, drop it */ /* drop connected client */
client_close(current_client); client_close(&client);
time2string(time(NULL), timestamp); fprintf(stderr, "[%s] dropped client %s @ %s\n",
fprintf(stderr, "[%s] dropped current client %s on port %u @ %s\n", __func__, __func__, client.ip_string, timestamp);
current_client->ip_string, server->port, timestamp);
/* make new client the current client */
memcpy(current_client, &new_client, sizeof(struct client_t));
time2string(time(NULL), timestamp);
fprintf(stderr, "[%s] accepted new client request %s on port %u @ %s\n", __func__,
current_client->ip_string, server->port, timestamp);
/* return 1 because current client was dropped */
return 1;
} }
else { else {
/* new connection should be rejected, close connection */ /* reject this client request */
close(new_client.socket); client_close(&new_client);
time2string(time(NULL), timestamp); time2string(time(NULL), timestamp);
fprintf(stderr, "[%s] rejected new client request %s on port %u @ %s\n", __func__, fprintf(stderr, "[%s] rejected new client request %s @ %s\n",
new_client.ip_string, server->port, timestamp); __func__, temp_client.ip_string, timestamp);
/* return 0 because new client was rejected */ return (void *) 1;
return 0;
} }
return (void *) 0;
} }