Startpunkten

Lab4/dbserver.c

@@ -0,0 +1,247 @@
+#include "db.h"
+
+void Kill_Process() {
+	kill(0, SIGTERM);
+	exit(0);
+}
+
+void P(char *lockfile) { /* Proberen */  	
+   int tempfd;
+   while((tempfd = creat(lockfile, 0)) < 0); /* Försök skapa låsfilen */
+   close(tempfd);
+}
+
+void V(char *lockfile) { /* Verhogen */
+	unlink(lockfile);
+}
+
+printsin(struct sockaddr_in *sin, char *m1, char *m2 ) {
+	struct hostent *gethostbyaddr(), *h;
+	printf ("%s %s\n", m1, m2);
+	printf ("Family %d addr %x port %d\n", sin -> sin_family,
+	ntohl(sin -> sin_addr.s_addr), ntohs(sin -> sin_port));
+	h = gethostbyaddr((char *)&sin->sin_addr, sizeof(int), AF_INET);
+	printf ("Symbolic host name <%s>\n",h->h_name);
+}
+
+void doAdd(msg *myMsg) {
+	int fd, i=0;
+  	printf("Adding %s\n", myMsg->name);
+	
+	P(READLOCK);
+	if((fd = open(FILENAME, O_CREAT|O_WRONLY|O_APPEND, PERMS)) < 0) {
+		myMsg->op = NACK; /* Return error to client */
+		exit(1);
+	}
+	write(fd, &myMsg->nr, NRSIZE);
+	write(fd, &myMsg->name, NAMESIZE);	
+
+	if((close(fd)) < 0) {
+		myMsg->op = NACK;
+		V(READLOCK);
+		return;
+	}
+	myMsg->op = ACK;
+	V(READLOCK);
+}
+
+void doDel(msg *myMsg) {
+	int i=0, j=0, file, temp;
+	struct stat st1;
+	struct stat st2;	
+	long a, b;
+	char c, nr[NRSIZE], name[NAMESIZE];
+	
+	P(READLOCK);
+	P(WRITELOCK);
+	if((file = open(FILENAME, O_RDONLY)) < 0) {
+		myMsg->op = NACK;
+		return;
+	}
+	if((temp = open(TMPFILE, O_RDWR|O_CREAT|O_TRUNC, PERMS)) < 0) {
+		myMsg->op = NACK;
+		return;
+	}
+	
+	while(read(file, nr, NRSIZE) > 0) {
+		read(file, name, NAMESIZE);
+		if(strcmp(nr, myMsg->nr) != 0) {
+			write(temp, nr, NRSIZE);
+			write(temp, name, NAMESIZE);
+		}
+	}
+	fstat(file, &st1);
+	a = st1.st_size;
+	fstat(temp, &st2);
+	b = st2.st_size;
+	
+	if((close(file)) < 0) {
+		myMsg->op = NACK;
+		return;
+	}
+	if((close(temp)) < 0) {
+		myMsg->op = NACK;
+		return;
+	}
+	if((temp = open(TMPFILE, O_RDONLY)) < 0) {
+		myMsg->op = NACK;
+		return;
+	}
+	if((file = open(FILENAME, O_RDWR|O_CREAT|O_TRUNC, PERMS)) < 0) {
+		myMsg->op = NACK;
+		return;
+	}
+		
+	while(read(temp, &c ,1) > 0){
+		write(file, &c, 1);
+	}
+	if((close(file)) < 0) {
+		myMsg->op = NACK;
+		return;
+	}
+	if((close(temp)) < 0) {
+		myMsg->op = NACK;
+		return;
+	}
+	if((unlink(TMPFILE)) < 0) {
+		myMsg->op = NACK;
+		return;
+	}
+	V(WRITELOCK);
+	V(READLOCK);
+	
+	if(a == b) {
+		myMsg->op = NACK;
+		return;
+	}
+	myMsg->op = ACK;
+}
+
+void doFindNumber(msg *myMsg) {
+	int file;
+	char nr[NRSIZE], name[NAMESIZE];	
+	
+	P(READLOCK);
+	if((file = open(FILENAME, O_RDONLY)) < 0) {
+		myMsg->op = NACK;
+		return;
+	}
+	
+	while(read(file, nr, NRSIZE) > 0){
+		read(file, name, NAMESIZE);
+		if(strcmp(name, myMsg->name) == 0) {
+			myMsg->op = PRN;
+			strcpy(myMsg->nr, nr);
+			V(READLOCK);
+			return;
+		}
+	}
+	myMsg->op = NACK;
+   close(file);
+   V(READLOCK);
+   return;
+}
+
+void doFindName(msg *myMsg) {
+	int file;
+	char nr[NRSIZE], name[NAMESIZE];	
+	
+	P(READLOCK);
+	if((file = open(FILENAME, O_RDONLY)) < 0) {
+		myMsg->op = NACK;
+		return;
+	}
+	
+	while(read(file, nr, NRSIZE) > 0){
+		read(file, name, NAMESIZE);
+		printf("\n nr=%s, myMsg->nr=%s",nr, myMsg->nr);
+		if(strcmp(nr, myMsg->nr) == 0) {
+			myMsg->op = PRN;
+			strcpy(myMsg->name, name);
+			V(READLOCK);
+			return;
+		}
+	}
+   close(file);
+   V(READLOCK);	
+	myMsg->op = NACK;
+}
+
+void doExit(msg *myMsg, int data_sockfd) {
+	printf("Quitting...\n");
+	close(data_sockfd);
+	exit(0);
+}
+
+main() {
+	int listener, childpid, data_sockfd, status, client_length, length;
+	msg myMsg;
+	struct sockaddr_in srvr_addr, client_addr;
+	signal(SIGCHLD, SIG_IGN);
+	signal(SIGINT, Kill_Process);
+	/*signal(SIGTERM, Kill_Process);*/
+
+	if((listener = socket( AF_INET, SOCK_STREAM, 0 )) < 0 ) {
+		perror("server: can't open stream socket");
+		exit(0);
+	}
+	bzero((char *) &srvr_addr, sizeof(srvr_addr));
+	srvr_addr.sin_family = AF_INET;
+	srvr_addr.sin_addr.s_addr = htons(INADDR_ANY);
+	srvr_addr.sin_port = 27015;
+
+	if(bind(listener, (struct sockaddr *)&srvr_addr, sizeof(srvr_addr)) < 0) {
+		perror("server: can't bind local address");
+		exit(0);
+	}
+	/* Print out the port number assigned to this process by bind(). */
+	length = sizeof(srvr_addr);
+	
+	if(getsockname(listener, (struct sockaddr *)&srvr_addr, &length) < 0) {
+		perror("server: can't get sockname");
+		exit(0);
+	}
+	printf("Port number %d\n", ntohs(srvr_addr.sin_port));
+	listen(listener,10);
+	
+	for(;;) {
+		/* Wait for a connection from a client process */
+		client_length = sizeof(client_addr);
+		if ((data_sockfd=accept(listener,
+	       (struct sockaddr *)&client_addr, &length)) < 0) {
+			perror("server: accept error");
+			exit(0);
+		}
+
+		printsin(&client_addr,"\nRSTREAM", "accepted connection from");
+		if((childpid = fork()) < 0) {
+			perror("server: fork error");
+			exit(0);
+		}
+		else if(childpid == 0) { /* Child process */	
+			close(listener);
+			while(1) {	
+				read(data_sockfd, &myMsg, sizeof(myMsg));
+
+				switch(myMsg.op) {
+					case 1: 	doAdd(&myMsg);
+							  	write(data_sockfd, &myMsg, sizeof(myMsg));
+							  	break;
+					case 2: 	doDel(&myMsg);
+							 	write(data_sockfd, &myMsg, sizeof(myMsg));
+								break;
+					case 3:	doFindNumber(&myMsg);
+							 	write(data_sockfd, &myMsg, sizeof(myMsg));
+								break;
+					case 4:	doFindName(&myMsg);
+							 	write(data_sockfd, &myMsg, sizeof(myMsg));
+								break;																
+					case 5: 	doExit(&myMsg, data_sockfd);
+										
+					default: break;
+				}
+				myMsg.op = ACK; /* töm struktens op så den inte är kvar till switchen */
+			}
+		}
+	}
+}