add option base

p-server.c

@@ -173,6 +173,39 @@ int send_response(int sock,int fd, uint8_t * buf, size_t bufsize){
 #endif
     return 0;
 }
+const char * help(const char * n){
+    const char * msg = "USASE : %s [Option] ...\n"
+    "Options and arguments: \n"
+    "-p port\t:set to port binding. couldn't set to 0\n"
+    "-h\t:print help message.\n";
+    printf(msg,n);
+    return msg;
+}
+/** return 0 ok. otherwise invalid format*/
+int parse_args(int argc,const char * argv[] , in_port_t * port){
+    int pos = 1;
+    const char * opt;
+    while (pos < argc)
+    {
+        opt = argv[pos++];
+        if (strcmp(opt,"-h") == 0 || strcmp(opt,"--help") == 0)
+        {
+            help(argv[0]);
+            return 2;
+        }
+        else if(strcmp(opt,"-p") == 0 || strcmp(opt,"--port") == 0){
+            if (pos < argc){
+                const char * value = argv[pos++];
+                *port = atoi(value);
+                if (port == 0){ // either not number or zero 
+                    return 2;
+                }
+            }
+            else return 2; //failed to find argument.
+        }
+    }
+    return 0;
+}
 static int sock;
 void safe_exit(){
     close(sock);
@@ -185,6 +218,11 @@ int main(int argc, const char *argv[]){
     int csock;
     int bufsize;
     int i;
+    in_port_t binding_port_number = SERVER_PORT;
+    if (argc > 1){
+        int d = parse_args(argc,argv,&binding_port_number);
+        if(d != 0 ) return d;
+    }
     sock = socket(AF_INET,SOCK_STREAM,0);
     atexit(safe_exit);
     if(sock < 0){
@@ -206,7 +244,7 @@ int main(int argc, const char *argv[]){
     
     addr.sin_addr.s_addr = htonl(INADDR_ANY); /*0.0.0.0 모든 네트워크 인터페이스에 묶임.*/
     addr.sin_family = AF_INET;
-    addr.sin_port = htons(SERVER_PORT);
+    addr.sin_port = htons(binding_port_number);
 
     if(bind(sock, (struct sockaddr *)&addr,sizeof(addr)) < 0){
         perror("bind failed");
@@ -215,7 +253,7 @@ int main(int argc, const char *argv[]){
         char ip_buf[INET_ADDRSTRLEN];
         const char * msg = inet_ntop(AF_INET,&addr.sin_addr,ip_buf,sizeof(ip_buf));
         assert(msg != NULL);
-        fprintf(stderr,"server bind on %s:%d\n",msg ,SERVER_PORT);
+        fprintf(stderr,"server bind on %s:%d\n",msg ,binding_port_number);
     }
     if(listen(sock,MAX_LISTEN_SOCKET) < 0){
         perror("listen failed");

server.c

@@ -171,6 +171,39 @@ int send_response(int sock,int fd, uint8_t * buf, size_t bufsize){
 #endif
     return 0;
 }
+const char * help(const char * n){
+    const char * msg = "USASE : %s [Option] ...\n"
+    "Options and arguments: \n"
+    "-p port\t:set to port binding. couldn't set to 0\n"
+    "-h\t:print help message.\n";
+    printf(msg,n);
+    return msg;
+}
+/** return 0 ok. otherwise invalid format*/
+int parse_args(int argc,const char * argv[] , in_port_t * port){
+    int pos = 1;
+    const char * opt;
+    while (pos < argc)
+    {
+        opt = argv[pos++];
+        if (strcmp(opt,"-h") == 0 || strcmp(opt,"--help") == 0)
+        {
+            help(argv[0]);
+            return 2;
+        }
+        else if(strcmp(opt,"-p") == 0 || strcmp(opt,"--port") == 0){
+            if (pos < argc){
+                const char * value = argv[pos++];
+                *port = atoi(value);
+                if (port == 0){ // either not number or zero 
+                    return 2;
+                }
+            }
+            else return 2; //failed to find argument.
+        }
+    }
+    return 0;
+}
 
 static int sock;
 void safe_exit(){
@@ -183,6 +216,12 @@ int main(int argc, const char *argv[]){
     socklen_t client_addr_len = sizeof(client_addr);
     int csock;
     int bufsize;
+    in_port_t binding_port_number = SERVER_PORT;
+    if (argc > 1){
+        int d = parse_args(argc,argv,&binding_port_number);
+        if(d != 0 ) return d;
+    }
+    
     sock = socket(AF_INET,SOCK_STREAM,0);
     atexit(safe_exit);
     if(sock < 0){
@@ -204,7 +243,7 @@ int main(int argc, const char *argv[]){
     
     addr.sin_addr.s_addr = htonl(INADDR_ANY); /*0.0.0.0 모든 네트워크 인터페이스에 묶임.*/
     addr.sin_family = AF_INET;
-    addr.sin_port = htons(SERVER_PORT);
+    addr.sin_port = htons(binding_port_number);
 
     if(bind(sock, (struct sockaddr *)&addr,sizeof(addr)) < 0){
         perror("bind failed");
@@ -213,7 +252,7 @@ int main(int argc, const char *argv[]){
         char ip_buf[INET_ADDRSTRLEN];
         const char * msg = inet_ntop(AF_INET,&addr.sin_addr,ip_buf,sizeof(ip_buf));
         assert(msg != NULL);
-        fprintf(stderr,"server bind on %s:%d\n",msg ,SERVER_PORT);
+        fprintf(stderr,"server bind on %s:%d\n",msg ,binding_port_number);
     }
 
     if(listen(sock,1) < 0){