add new repoHEADmaster

7 files changed, 827 insertions, 0 deletions

diff --git a/Bachelor/Verteilte Systeme/Praktikum1/Makefile b/Bachelor/Verteilte Systeme/Praktikum1/Makefile
new file mode 100644
index 0000000..2e568e8
--- /dev/null
+++ b/Bachelor/Verteilte Systeme/Praktikum1/Makefile
@@ -0,0 +1,14 @@
+all: tcpserv tcpcli

+

+tcpserv: tcpserv.o

+	g++ tcpserv.o -o tcpserv

+tcpcli: tcpcli.o

+	g++ tcpcli.o -o tcpcli

+

+tcpserv.o:

+	g++ -c -o tcpserv.o tcpserv.cpp

+tcpcli.o:

+	g++ -c -o tcpcli.o tcpcli.cpp

+

+clean:

+	rm -f *.o tcpserv tcpcli

diff --git a/Bachelor/Verteilte Systeme/Praktikum1/README b/Bachelor/Verteilte Systeme/Praktikum1/README
new file mode 100644
index 0000000..74355c2
--- /dev/null
+++ b/Bachelor/Verteilte Systeme/Praktikum1/README
@@ -0,0 +1,22 @@
+1. Die Programme sind zu uebersetzen (auf Server und Client Rechner):
+     $ make tcpserv
+     g++     tcpserv.cpp   -o tcpserv
+	 $
+	 $ make tcpcli
+	 g++     tcpcli.cpp   -o tcpcli
+	 $
+
+2. Nun kann das Serverprogramm auf dem Server gestartet werden:
+     $ tcpserv $
+	 $
+
+3. Auf jedem Clientrechner kann nun der Client gestartet werden.
+	 $ tcpcli
+	 Dies ist die erste Zeile
+	 Dies ist die erste Zeile
+	 2. Nachricht
+	 2. Nachricht
+	 Letzte Nachricht
+	 Letzte Nachricht
+	 ^D
+	 $
diff --git a/Bachelor/Verteilte Systeme/Praktikum1/error.cpp b/Bachelor/Verteilte Systeme/Praktikum1/error.cpp
new file mode 100644
index 0000000..5bf172d
--- /dev/null
+++ b/Bachelor/Verteilte Systeme/Praktikum1/error.cpp
@@ -0,0 +1,331 @@
+/************************************************************************

+ * Error handling routines.

+ *

+ * The functions in this file are independent of any application

+ * variables, and may be used with any C program.

+ * Either of the names CLIENT or SERVER may be defined when compiling

+ * this function.  If neither are defined, we assume CLIENT.

+ */

+

+//#include	<varargs.h>

+#include <string.h>

+#include <stdarg.h>

+#include <errno.h>

+

+#include <iostream>

+using namespace std;

+

+#ifdef	CLIENT

+#ifdef	SERVER

+cant define both CLIENT and SERVER

+#endif

+#endif

+

+#ifndef	CLIENT

+#ifndef	SERVER

+#define	CLIENT	1		/* default to client */

+

+#endif

+#endif

+

+#ifndef	NULL

+#define	NULL	((void *) 0)

+#endif

+

+char	*pname = NULL;

+

+#ifdef	CLIENT			/* these all output to stderr */

+

+			/* ------------------- BEGIN CLIENT ------------------- */

+

+/*

+ * Print the UNIX errno value.

+ */

+

+void my_perror()

+{

+	//char	*sys_err_str();

+	char *str =  strerror(errno);

+	cerr << str << endl;

+	//fprintf(stderr, " %s\n", sys_err_str());

+}

+/*

+ * Print the UNIX errno value.

+ * We just append it to the end of the emesgstr[] array.

+ */

+

+ 

+ 

+/*

+ * Fatal error.  Print a message and terminate.

+ * Don't dump core and don't print the system's errno value.

+ *

+ *	err_quit(str, arg1, arg2, ...)

+ *

+ * The string "str" must specify the conversion specification for any args.

+ */

+

+/*VARARGS1*/

+ 

+void err_quit(char *fmt, ...)

+{

+	va_list		args;

+

+	va_start(args, fmt);

+	if (pname != NULL)

+		cerr << pname;

+	fmt = va_arg(args, char *);

+	vfprintf(stderr, fmt, args);

+	fputc('\n', stderr);

+	va_end(args);

+

+	exit(1);

+}

+

+/*

+ * Fatal error related to a system call.  Print a message and terminate.

+ * Don't dump core, but do print the system's errno value and its

+ * associated message.

+ *

+ *	err_sys(str, arg1, arg2, ...)

+ *

+ * The string "str" must specify the conversion specification for any args.

+ */

+

+/*VARARGS1*/

+void err_sys(char *fmt, ...)

+{

+	va_list		args;

+	va_start(args, fmt);

+	if (pname != NULL) {

+		cerr << "if (pname != NULL) {" << endl;

+		fprintf(stderr, "%s: ", pname);

+

+	}

+	fmt = va_arg(args, char *);

+	

+	vfprintf(stderr, fmt, args);

+	va_end(args);

+	

+	my_perror();

+

+	exit(1);

+}

+

+/*

+ * Recoverable error.  Print a message, and return to caller.

+ *

+ *	err_ret(str, arg1, arg2, ...)

+ *

+ * The string "str" must specify the conversion specification for any args.

+ */

+

+/*VARARGS1*/

+void err_ret(char *fmt, ...)

+{

+	va_list		args;

+

+

+	va_start(args, fmt);

+	if (pname != NULL)

+		fprintf(stderr, "%s: ", pname);

+	fmt = va_arg(args, char *);

+	vfprintf(stderr, fmt, args);

+	va_end(args);

+

+	my_perror();

+

+	fflush(stdout);

+	fflush(stderr);

+

+	return;

+}

+

+/*

+ * Fatal error.  Print a message, dump core (for debugging) and terminate.

+ *

+ *	err_dump(str, arg1, arg2, ...)

+ *

+ * The string "str" must specify the conversion specification for any args.

+ */

+

+/*VARARGS1*/

+void err_dump(char *fmt, ...)

+{

+	va_list		args;

+	

+

+	va_start(args, fmt);

+	if (pname != NULL)

+		fprintf(stderr, "%s: ", pname);

+	fmt = va_arg(args, char *);

+	vfprintf(stderr, fmt, args);

+	va_end(args);

+

+	my_perror();

+

+	fflush(stdout);		/* abort doesn't flush stdio buffers */

+	fflush(stderr);

+

+	abort();		/* dump core and terminate */

+	exit(1);		/* shouldn't get here */

+}

+

+#endif	/* ------------------- END CLIENT ------------------- */

+		/* ------------------- BEGIN SERVER ------------------- */

+#ifdef	SERVER

+

+#ifdef	BSD

+/*

+ * Under BSD, these server routines use the syslog(3) facility.

+ * They don't append a newline, for example.

+ */

+

+#include	<syslog.h>

+

+#else	/* not BSD */

+/*

+ * There really ought to be a better way to handle server logging

+ * under System V.

+ */

+

+#define	syslog(a,b)	cerr << "syslog: "<< (b)

+#define	openlog(a,b,c)	cerr << (a)

+

+#endif	/* BSD */

+/*

+ * Print the UNIX errno value.

+ * We just append it to the end of the emesgstr[] array.

+ */

+

+char	emesgstr[255] = {"test"};	/* used by all server routines */

+void my_perror()

+{

+	

+	// register int	len;

+	//char		*sys_err_str();

+//	len = strlen(emesgstr);

+	cerr << emesgstr 

+		 << strerror(errno)

+		 << endl;

+	//sprintf(emesgstr + len, " %s", sys_err_str());

+}

+

+

+

+/*

+ * Identify ourself, for syslog() messages.

+ *

+ * LOG_PID is an option that says prepend each message with our pid.

+ * LOG_CONS is an option that says write to console if unable to send

+ * the message to syslogd.

+ * LOG_DAEMON is our facility.

+ */

+

+void err_init(char	*ident)

+{

+	openlog(ident, (LOG_PID | LOG_CONS), LOG_DAEMON);

+}

+

+/*

+ * Fatal error.  Print a message and terminate.

+ * Don't print the system's errno value.

+ *

+ *	err_quit(str, arg1, arg2, ...)

+ *

+ * The string "str" must specify the conversion specification for any args.

+ */

+

+/*VARARGS1*/

+void err_quit(char *fmt, ...)

+{

+	va_list		args;

+	va_start(args, fmt);

+	fmt = va_arg(args, char *);

+	vsprintf(emesgstr, fmt, args);

+	va_end(args);

+

+	syslog(LOG_ERR, emesgstr);

+

+	exit(1);

+}

+

+/*

+ * Fatal error related to a system call.  Print a message and terminate.

+ * Don't dump core, but do print the system's errno value and its

+ * associated message.

+ *

+ *	err_sys(str, arg1, arg2, ...)

+ *

+ * The string "str" must specify the conversion specification for any args.

+ */

+

+/*VARARGS1*/

+void err_sys(char *fmt, ...)

+

+{

+	cerr << "err_sys: " << fmt << endl;

+	va_list		args;

+	va_start(args, fmt);

+	fmt = va_arg(args, char *);

+	vsprintf(emesgstr, fmt, args);

+	va_end(args);

+

+	my_perror();

+	syslog(LOG_ERR, emesgstr);

+

+	exit(1);

+}

+

+/*

+ * Recoverable error.  Print a message, and return to caller.

+ *

+ *	err_ret(str, arg1, arg2, ...)

+ *

+ * The string "str" must specify the conversion specification for any args.

+ */

+

+/*VARARGS1*/

+void err_ret(char *fmt, ...)

+

+{

+	va_list		args;

+	

+	va_start(args, fmt);

+	fmt = va_arg(args, char *);

+	vsprintf(emesgstr, fmt, args);

+	va_end(args);

+

+	my_perror();

+	syslog(LOG_ERR, emesgstr);

+

+	return;

+}

+

+/*

+ * Fatal error.  Print a message, dump core (for debugging) and terminate.

+ *

+ *	err_dump(str, arg1, arg2, ...)

+ *

+ * The string "str" must specify the conversion specification for any args.

+ */

+

+/*VARARGS1*/

+void err_dump(char *fmt, ...)

+

+{

+	va_list		args;

+	va_start(args,fmt);

+	fmt = va_arg(args, char *);

+	vsprintf(emesgstr, fmt, args);

+	va_end(args);

+

+	my_perror();

+	syslog(LOG_ERR, emesgstr);

+

+	abort();		/* dump core and terminate */

+	exit(1);		/* shouldn't get here */

+}

+

+

+#endif	/* ------------------- SERVER ------------------- */

diff --git a/Bachelor/Verteilte Systeme/Praktikum1/inet.h b/Bachelor/Verteilte Systeme/Praktikum1/inet.h
new file mode 100644
index 0000000..6af7e71
--- /dev/null
+++ b/Bachelor/Verteilte Systeme/Praktikum1/inet.h
@@ -0,0 +1,19 @@
+/************************************************************************

+ * Definitions for TCP and UDP client/server programs.

+ */

+

+#include	<stdio.h>

+#include	<fcntl.h>

+#include	<sys/types.h>

+#include 	<sys/socket.h>

+#include	<asm/socket.h>

+#include	<arpa/inet.h>

+#include 	<netinet/in.h>

+

+

+

+

+

+#define	SERV_TCP_PORT	9018

+//#define	SERV_HOST_ADDR	"10.0.0.200"	/* host addr for server */

+#define SERV_HOST_ADDR	"127.0.0.1"		/* Localhost */

diff --git a/Bachelor/Verteilte Systeme/Praktikum1/tcpcli.cpp b/Bachelor/Verteilte Systeme/Praktikum1/tcpcli.cpp
new file mode 100644
index 0000000..ac10492
--- /dev/null
+++ b/Bachelor/Verteilte Systeme/Praktikum1/tcpcli.cpp
@@ -0,0 +1,129 @@
+/************************************************************************
+ *
+ * Example of client using TCP protocol.
+ *
+ ***********************************************************************/
+#include <unistd.h>
+#include "inet.h"
+#include "error.cpp"
+#include "util.cpp"
+#include <iostream>
+using namespace std;
+
+const int MAXLINE=255; // max length of a line
+
+// send message msg to server and receive response in resp
+void mySend(int sockfd, char *msg, char *resp) {
+
+
+	int n; // Länge des Strings
+	// Daten senden
+	n = strlen(msg);
+	if (writen(sockfd, msg, n) != n)
+		err_sys("str_cli: writen error on socket"); // Fehler beim Schreiben
+
+	// Daten empfangen
+	n = readline(sockfd, resp, MAXLINE);
+	if (n < 0)
+		err_dump("str_cli: readline error");
+	resp[n] = 0;	/* null terminate */
+}
+
+
+void str_cli(FILE *fp, int sockfd)
+{
+	int	n;
+	char	sendline[MAXLINE], recvline[MAXLINE + 1];
+
+
+
+	// Auswahl der Optionen (Eintragen / Suchen)
+	int m_Auswahl = '0';
+
+	while (true) {
+
+		cout<<"Telefonbuch\n\nBitte auswählen:\n";
+		cout<<" 1: eintragen\n";
+		cout<<" 2: suchen\n";
+		cout<<" 3: beenden\n";
+		cin>>m_Auswahl;
+		switch (m_Auswahl) {
+			case (1):
+				// Neuen Eintrag im Telefonbuch
+				cout<<"Eintragen:\n";
+				char m_Name[50];
+				char m_Tel[50];
+
+				cout<<"Name: ";  scanf("%s", &m_Name);  strcat(m_Name, "\n");
+				cout<<"Tel: ";   scanf("%s", &m_Tel);   strcat(m_Tel, "\n");
+
+				mySend(sockfd, "addEntry\n", recvline);
+				if (strcmp(recvline,"OK\n") != 0)
+					printf("Error: %s\n", recvline);
+				mySend(sockfd, m_Name, recvline);
+				if (strcmp(recvline,"OK\n") != 0)
+					printf("Error: %s\n", recvline);
+				mySend(sockfd, m_Tel, recvline);
+				if (strcmp(recvline,"OK\n") != 0)
+					printf("Error: %s\n", recvline);
+				break;
+			case (2):
+				// Eintrag im Telefonbuch suchen
+				cout<<"Suchen\n";
+				char m_Search[50];
+				cout<<"Name: ";  scanf("%s", &m_Search);  strcat(m_Search, "\n");
+
+				mySend(sockfd, "searchEntry\n", recvline);
+				if (strcmp(recvline,"OK\n") != 0)
+					printf("Error: %s\n", recvline);
+				mySend(sockfd, m_Search, recvline);
+				printf("Ergebnis: %s\n", recvline);
+
+				break;
+			case (3):
+				mySend(sockfd,"end\n",recvline);
+				cout<<"Client beendet...\n";
+				return;
+				break;
+			default:
+				cout<<"Falsche Eingabe\n";
+				break;
+		}
+	}
+
+
+}
+/***********************************************************************/
+
+/************************************************************************
+ * main function, client for TCP/IP echo server
+ */
+int main(int argc, char** argv)
+{
+	int			sockfd;
+	struct sockaddr_in	serv_addr;
+
+	pname = argv[0];
+
+	// Fill in the structure "serv_addr" with the address of the
+	// server that we want to connect with.
+	bzero((char *) &serv_addr, sizeof(serv_addr));
+	serv_addr.sin_family      = AF_INET;
+	serv_addr.sin_addr.s_addr = inet_addr(SERV_HOST_ADDR);
+	serv_addr.sin_port        = htons(SERV_TCP_PORT);
+
+    // Open a TCP socket (an Internet stream socket).
+	if ( (sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
+		err_sys("client: can't open stream socket");
+
+	// Connect to the server.
+	if (connect(sockfd, (struct sockaddr *) &serv_addr,
+							sizeof(serv_addr)) < 0)
+		err_sys("client: can't connect to server");
+
+	str_cli(stdin, sockfd);		/* do it all */
+
+	close(sockfd);
+	exit(0);
+}
+/***********************************************************************/
diff --git a/Bachelor/Verteilte Systeme/Praktikum1/tcpserv.cpp b/Bachelor/Verteilte Systeme/Praktikum1/tcpserv.cpp
new file mode 100644
index 0000000..e23418e
--- /dev/null
+++ b/Bachelor/Verteilte Systeme/Praktikum1/tcpserv.cpp
@@ -0,0 +1,226 @@
+static char rcsid[] = "$Id: tcpserv.c,v 1.1 2001/12/02 12:13:52 as Exp as $";
+/************************************************************************
+ *
+ * Example of server using TCP protocol.
+ *
+ ***********************************************************************/
+
+#include <unistd.h>
+#include <sys/stat.h>               // open()
+#include "inet.h"
+#include "error.cpp"
+#include "util.cpp"
+#include <iostream>
+
+#include <time.h>
+#include <fstream>
+
+using namespace std;
+
+// Constant definitions
+//
+// maximum line length
+const int MAXLINE=255;
+
+// structure for phone book records
+struct telEintrag {	// Einzelne Einträge im Telefonbuch
+	char name[50];
+	char tel[50];
+};
+
+// max. 50 records in a phone book
+// global variables
+//
+// TODO: change to file or shared memory
+// global variables are not good with fork()
+//
+telEintrag telBuch[50];	// 50 Einträge möglich
+int telCount = 0;	// Position des nächsten freien Platzes
+
+// write a line to socket sockfd
+void myWrite(int sockfd, char *line) {
+	int	n;
+	// send reply
+	n = strlen(line);
+	if (writen(sockfd, line, n) != n) {
+		err_dump("str_echo: writen error");
+	}
+}
+
+// read line from socket sockfd
+void myRead(int sockfd, char *line) {
+	int	n;
+
+
+	// receive data into line
+	n = readline(sockfd, line, MAXLINE);
+
+	// error handling
+	if (n == 0) {
+		return;		/* connection terminated */
+	}
+	else if (n < 0) {
+		err_dump("str_echo: readline error");
+	}
+
+
+	// console logging
+	
+	// time_t structure variable myTime
+	time_t myTime;
+	
+	//  read time into myTime
+	time(&myTime);
+	
+	// char array for time conversion
+	char tmpTime[25];
+
+	// copy converted time into char array
+	strcpy(tmpTime, ctime(&myTime));
+
+	// append string terminating binary 0
+	tmpTime[strlen(tmpTime)-1] = '\0';
+
+	// print time and received line to stdout
+	printf("[%s] Nachricht: %s",tmpTime,line);
+
+}
+
+
+void str_echo(int sockfd)
+{
+	int	n;
+	char	line[MAXLINE];
+
+
+	for ( ; ; ) {
+		// read line from socket
+		myRead(sockfd, line);
+
+		// if "addEntry"-command was sent
+		if (strcmp(line, "addEntry\n") == 0) {
+			// send back "OK", we understood the command
+			myWrite(sockfd, "OK\n");
+
+			// now we receive the name
+			myRead(sockfd, line);
+			// name received
+			myWrite(sockfd, "OK\n");
+			// save it in local memory
+			strcpy(telBuch[telCount].name, line);
+
+			// now we receive the phone number
+			myRead(sockfd, line);
+			// number received
+			myWrite(sockfd, "OK\n");
+			// save the number in local memory
+			strcpy(telBuch[telCount].tel, line);
+			// next time we fill the next array element
+			telCount++;
+			// we did it
+			printf("Neuer Eintrag im Telefonbuch.\n");
+
+		} else 
+			// the "searchEntry"-command was sent
+			if (strcmp(line, "searchEntry\n") == 0) {
+			// send back "OK", we understood the command
+			myWrite(sockfd, "OK\n");
+
+			// receive the search string
+			myRead(sockfd, line);
+			// search the entry
+			int i=0;
+			bool found = false;
+			for (i; i < telCount; i++) {
+
+				if (strcmp(telBuch[i].name, line) == 0) {
+					found = true;
+					// we found an entry
+					// send back the phone number
+					myWrite(sockfd, telBuch[i].tel);
+				}
+			}
+			// we did not find anything
+			if (found == false)
+				myWrite(sockfd, "Nicht gefunden.\n");
+
+		} else if (strcmp(line,"end\n")==0)
+		{
+			// client sent end command
+			// exiting...
+			myWrite(sockfd,"Server exiting... \n");
+			exit(0);
+		}
+		else
+		{
+			// an undefined command was sent from client
+			myWrite(sockfd, "Command not found.\n");
+
+		}
+
+
+	}
+}
+/***********************************************************************/
+
+/************************************************************************
+ * main function, server for the TCP/IP echo server
+ */
+int main(int argc, char **argv)
+{
+	int			sockfd, newsockfd, clilen, childpid;
+	// structures of socket addresses
+	struct sockaddr_in	cli_addr, serv_addr;
+	pname = argv[0];
+
+	// Open a TCP socket (an Internet stream socket).
+	if ( (sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
+		err_dump("server: can't open stream socket");
+
+	 // Bind our local address so that the client can send to us.
+	
+	 // make sure zeros are in serv_addr
+	bzero((char *) &serv_addr, sizeof(serv_addr));
+	// now fill in information, which we need
+	serv_addr.sin_family      = AF_INET;
+	// INADDR_ANY: System definiton -> accept connections on every interface
+	// htonl: convert byte order (host to network long)
+	serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
+	// SERV_TCP_PORT defined in inet.h
+	// htons: convert byte order (host to network short)
+	serv_addr.sin_port        = htons(SERV_TCP_PORT);
+	
+	// bind sockfd to socket address serv_addr (Server)
+	if (bind(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0)
+		err_dump("server: can't bind local address");
+
+	// mark socket to accept connections
+	// limit 5 connections backlog in queue
+	listen(sockfd, 5);
+
+	for ( ; ; ) {
+		 // Wait for a connection from a client process.
+		 // This is an example of a concurrent server.
+
+		clilen = sizeof(cli_addr);
+		// make new socket for client connection and return
+		// the file descriptor of this socket
+ 		newsockfd = accept(sockfd, (struct sockaddr *) &cli_addr,
+                                    (socklen_t *) &clilen);
+
+		if (newsockfd < 0)
+			err_dump("server: accept error");
+
+		if ( (childpid = fork()) < 0)
+			err_dump("server: fork error");
+
+		else if (childpid == 0) {	// child process
+			printf("Verbinung aufgebaut.\n");
+			close(sockfd);		    // close original socket 
+			str_echo(newsockfd);	// process the request 
+			exit(0);
+		}
+		close(newsockfd);		// parent process 
+	}
+}
+/***********************************************************************/
diff --git a/Bachelor/Verteilte Systeme/Praktikum1/util.cpp b/Bachelor/Verteilte Systeme/Praktikum1/util.cpp
new file mode 100644
index 0000000..88c8f66
--- /dev/null
+++ b/Bachelor/Verteilte Systeme/Praktikum1/util.cpp
@@ -0,0 +1,86 @@
+/************************************************************************

+ *

+ * Utility functions to use with sockets

+ *

+ ************************************************************************

+

+/************************************************************************

+ *

+ * Read "n" bytes from a descriptor.

+ * Use in place of read() when fd is a stream socket.

+ */

+#include <iostream>

+using namespace std;

+

+int readn(int fd, char* ptr, int nbytes)

+{

+	int	nleft, nread;

+

+	nleft = nbytes;

+	while (nleft > 0) {

+		nread = read(fd, ptr, nleft);

+		if (nread < 0)

+			return(nread);		/* error, return < 0 */

+		else if (nread == 0)

+			break;			/* EOF */

+

+		nleft -= nread;

+		ptr   += nread;

+	}

+	return(nbytes - nleft);		/* return >= 0 */

+}

+/************************************************************************

+

+/************************************************************************

+ *

+ * Read a line from a descriptor.  Read the line one byte at a time,

+ * looking for the newline.  We store the newline in the buffer,

+ * then follow it with a null (the same as fgets(3)).

+ * We return the number of characters up to, but not including,

+ * the null (the same as strlen(3)).

+ */

+int readline(int fd,char* ptr, int maxlen)

+{

+	int	n, rc;

+	char	c;

+

+	for (n = 1; n < maxlen; n++) {

+		if ( (rc = read(fd, &c, 1)) == 1) {

+			*ptr++ = c;

+			if (c == '\n')

+				break;

+		} else if (rc == 0) {

+			if (n == 1)

+				return(0);	/* EOF, no data read */

+			else

+				break;		/* EOF, some data was read */

+		} else

+			return(-1);	/* error */

+	}

+

+	*ptr = 0;

+	return(n);

+}

+/************************************************************************

+

+/************************************************************************

+ *

+ * Write "n" bytes to a descriptor.

+ * Use in place of write() when fd is a stream socket.

+ */

+int writen(int fd, char* ptr, int nbytes)

+{

+	int	nleft, nwritten;

+

+	nleft = nbytes;

+	while (nleft > 0) {

+		nwritten = write(fd, ptr, nleft);

+		if (nwritten <= 0)

+			return(nwritten);		/* error */

+

+		nleft -= nwritten;

+		ptr   += nwritten;

+	}

+	return(nbytes - nleft);

+}

+/************************************************************************/