/*
client ---- use TCP.
*/
#include < unistd.h >
#include < signal.h >
#include < sys / types.h >
#include < sys / socket.h >
#include < netinet / in .h > /* struct sockaddr_in */
#define MAXLINE 80
#define SERV_PORT 8000
void sig_pipe( int signo)
{
/* do nothing. */
}
int main( int argc, char * argv[])
{
struct sockaddr_in servaddr;
char buf[MAXLINE];
int sockfd, n;
struct sigaction newact;
newact.sa_handler = sig_pipe;
sigemptyset( & newact.sa_mask);
newact.sa_flags = 0 ;
sigaction(SIGPIPE, & newact, NULL);
sockfd = socket(AF_INET, SOCK_STREAM, 0 ); /
bzero( & servaddr, sizeof (servaddr));
servaddr.sin_family = AF_INET;
inet_pton(AF_INET, " 127.0.0.1 " , & servaddr.sin_addr);
servaddr.sin_port = htons(SERV_PORT);
connect(sockfd, ( struct sockaddr * ) & servaddr, sizeof (servaddr));
while (fgets(buf, MAXLINE, stdin) != NULL) {
if (write(sockfd, buf, strlen(buf)) < 0 ) {
perror( " write " );
exit( 1 );
}
n = read(sockfd, buf, MAXLINE);
if (n == 0 ) {
printf( " the server has been closed.\n " );
break ;
}
else
write(STDOUT_FILENO, buf, n);
}
close(sockfd);
return 0 ;
}
#include < unistd.h >
#include < signal.h >
#include < sys / types.h >
#include < sys / socket.h >
#include < netinet / in .h > /* struct sockaddr_in */
#define MAXLINE 80
#define SERV_PORT 8000
void sig_pipe( int signo)
{
/* do nothing. */
}
int main( int argc, char * argv[])
{
struct sockaddr_in servaddr;
char buf[MAXLINE];
int sockfd, n;
struct sigaction newact;
newact.sa_handler = sig_pipe;
sigemptyset( & newact.sa_mask);
newact.sa_flags = 0 ;
sigaction(SIGPIPE, & newact, NULL);
sockfd = socket(AF_INET, SOCK_STREAM, 0 ); /
bzero( & servaddr, sizeof (servaddr));
servaddr.sin_family = AF_INET;
inet_pton(AF_INET, " 127.0.0.1 " , & servaddr.sin_addr);
servaddr.sin_port = htons(SERV_PORT);
connect(sockfd, ( struct sockaddr * ) & servaddr, sizeof (servaddr));
while (fgets(buf, MAXLINE, stdin) != NULL) {
if (write(sockfd, buf, strlen(buf)) < 0 ) {
perror( " write " );
exit( 1 );
}
n = read(sockfd, buf, MAXLINE);
if (n == 0 ) {
printf( " the server has been closed.\n " );
break ;
}
else
write(STDOUT_FILENO, buf, n);
}
close(sockfd);
return 0 ;
}
/*
client ---- use UDP.
*/
#include < unistd.h >
#include < netinet / in .h >
#define MAXLINE 80
#define SERV_PORT 8000
int main( int argc, char * argv[])
{
struct sockaddr_in servaddr;
char buf[MAXLINE];
int sockfd, n;
socklen_t servaddr_len;
sockfd = socket(AF_INET, SOCK_DGRAM, 0 ); /* different from TCP. */
bzero( & servaddr, sizeof (servaddr));
servaddr.sin_family = AF_INET;
inet_pton(AF_INET, " 127.0.0.1 " , & servaddr.sin_addr);
servaddr.sin_port = htons(SERV_PORT);
while (fgets(buf, MAXLINE, stdin) != NULL) {
n = sendto(sockfd, buf, strlen(buf), 0 , ( struct sockaddr * ) & servaddr,
sizeof (servaddr)); /* different from TCP. */
if (n == - 1 )
perr_exit( " sendto error " );
n = recvfrom(sockfd, buf, MAXLINE, 0 , NULL, 0 ); /* different from TCP. */
if (n == - 1 )
perr_exit( " recvfrom error " );
write(STDOUT_FILENO, buf, n);
}
close(sockfd);
return 0 ;
}
#include < unistd.h >
#include < netinet / in .h >
#define MAXLINE 80
#define SERV_PORT 8000
int main( int argc, char * argv[])
{
struct sockaddr_in servaddr;
char buf[MAXLINE];
int sockfd, n;
socklen_t servaddr_len;
sockfd = socket(AF_INET, SOCK_DGRAM, 0 ); /* different from TCP. */
bzero( & servaddr, sizeof (servaddr));
servaddr.sin_family = AF_INET;
inet_pton(AF_INET, " 127.0.0.1 " , & servaddr.sin_addr);
servaddr.sin_port = htons(SERV_PORT);
while (fgets(buf, MAXLINE, stdin) != NULL) {
n = sendto(sockfd, buf, strlen(buf), 0 , ( struct sockaddr * ) & servaddr,
sizeof (servaddr)); /* different from TCP. */
if (n == - 1 )
perr_exit( " sendto error " );
n = recvfrom(sockfd, buf, MAXLINE, 0 , NULL, 0 ); /* different from TCP. */
if (n == - 1 )
perr_exit( " recvfrom error " );
write(STDOUT_FILENO, buf, n);
}
close(sockfd);
return 0 ;
}
/*
client ---- use UNIX Domain Socket IPC.
*/
#include < stddef.h >
#include < sys / socket.h >
#include < sys / un.h >
int main( void )
{
int fd, size;
struct sockaddr_un un;
if ((fd = socket(AF_UNIX, SOCK_STREAM, 0 )) < 0 ) {
perror( " socket error " );
exit( 1 );
}
un.sun_family = AF_UNIX;
strcpy(un.sun_path, " foo.socket " );
size = offsetof( struct sockaddr_un, sun_path) + strlen(un.sun_path);
if (bind(fd, ( struct sockaddr * ) & un, size) < 0 ) {
perror( " bind error " );
exit( 1 );
}
printf( " UNIX domain socket bound\n " );
exit( 0 );
}
#define CLI_PATH "/var/tmp" /* +5 for pid = 14 chars */
/* *
* Create a client endpoint and connect to a server.
* Returns fd if all OK, <0 on error.
*/
int cli_conn( const char * name)
{
int fd, len, err, rval;
struct sockaddr_un un;
/* create a UNIX domain stream socket */
if ((fd = socket(AF_UNIX, SOCK_STREAM, 0 )) < 0 )
return - 1 ;
memset( & un, 0 , sizeof (un));
un.sun_family = AF_UNIX;
sprintf(un.sun_path, " %s%05d " , CLI_PATH, getpid());
len = offsetof( struct sockaddr_un, sun_path) + strlen(un.sun_path);
unlink(un.sun_path); /* in case it already exists */
if (bind(fd, ( struct sockaddr * ) & un, len) < 0 ) {
rval = - 2 ;
goto errout;
}
memset( & un, 0 , sizeof (un));
un.sun_family = AF_UNIX;
strcpy(un.sun_path, name);
len = offsetof( struct sockaddr_un, sun_path) + strlen(name);
if (connect(fd, ( struct sockaddr * ) & un, len) < 0 ) {
rval = - 4 ;
goto errout;
}
return fd;
errout:
err = errno;
close(fd);
errno = err;
return rval;
}
#include < stddef.h >
#include < sys / socket.h >
#include < sys / un.h >
int main( void )
{
int fd, size;
struct sockaddr_un un;
if ((fd = socket(AF_UNIX, SOCK_STREAM, 0 )) < 0 ) {
perror( " socket error " );
exit( 1 );
}
un.sun_family = AF_UNIX;
strcpy(un.sun_path, " foo.socket " );
size = offsetof( struct sockaddr_un, sun_path) + strlen(un.sun_path);
if (bind(fd, ( struct sockaddr * ) & un, size) < 0 ) {
perror( " bind error " );
exit( 1 );
}
printf( " UNIX domain socket bound\n " );
exit( 0 );
}
#define CLI_PATH "/var/tmp" /* +5 for pid = 14 chars */
/* *
* Create a client endpoint and connect to a server.
* Returns fd if all OK, <0 on error.
*/
int cli_conn( const char * name)
{
int fd, len, err, rval;
struct sockaddr_un un;
/* create a UNIX domain stream socket */
if ((fd = socket(AF_UNIX, SOCK_STREAM, 0 )) < 0 )
return - 1 ;
memset( & un, 0 , sizeof (un));
un.sun_family = AF_UNIX;
sprintf(un.sun_path, " %s%05d " , CLI_PATH, getpid());
len = offsetof( struct sockaddr_un, sun_path) + strlen(un.sun_path);
unlink(un.sun_path); /* in case it already exists */
if (bind(fd, ( struct sockaddr * ) & un, len) < 0 ) {
rval = - 2 ;
goto errout;
}
memset( & un, 0 , sizeof (un));
un.sun_family = AF_UNIX;
strcpy(un.sun_path, name);
len = offsetof( struct sockaddr_un, sun_path) + strlen(name);
if (connect(fd, ( struct sockaddr * ) & un, len) < 0 ) {
rval = - 4 ;
goto errout;
}
return fd;
errout:
err = errno;
close(fd);
errno = err;
return rval;
}
/*
server ---- use TCP.
*/
/*
server ---- use UDP.
*/
#define MAXLINE 80
#define SERV_PORT 8000
int main( void )
{
struct sockaddr_in servaddr, cliaddr;
socklen_t cliaddr_len;
int sockfd;
char buf[MAXLINE];
char str[INET_ADDRSTRLEN];
int i, n;
sockfd = Socket(AF_INET, SOCK_DGRAM, 0 );
bzero( & servaddr, sizeof (servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
servaddr.sin_port = htons(SERV_PORT);
Bind(sockfd, ( struct sockaddr * ) & servaddr, sizeof (servaddr));
printf( " Accepting connection
\n
"
);
while ( 1 ) {
cliaddr_len = sizeof (cliaddr);
n = recvfrom(sockfd, buf, MAXLINE, 0 , ( struct sockaddr * ) & cliaddr, & cliaddr_len);
if (n == - 1 )
perr_exit( " recvfrom error " );
printf( " received from %s at PORT %d\n " ,
inet_ntop(AF_INET, & cliaddr.sin_addr, str, sizeof (str)),
ntohs(cliaddr.sin_port));
for (i = 0 ; i < n; i ++ )
buf[i] = toupper(buf[i]);
n = sendto(sockfd, buf, n, 0 , ( struct sockaddr * ) & cliaddr, sizeof (cliaddr));
if (n == - 1 )
perr_exit( " sendto error " );
}
}
#define MAXLINE 80
#define SERV_PORT 8000
int main( void )
{
struct sockaddr_in servaddr, cliaddr;
socklen_t cliaddr_len;
int sockfd;
char buf[MAXLINE];
char str[INET_ADDRSTRLEN];
int i, n;
sockfd = Socket(AF_INET, SOCK_DGRAM, 0 );
bzero( & servaddr, sizeof (servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
servaddr.sin_port = htons(SERV_PORT);
Bind(sockfd, ( struct sockaddr * ) & servaddr, sizeof (servaddr));
printf( " Accepting connection
\n
"
);while ( 1 ) {
cliaddr_len = sizeof (cliaddr);
n = recvfrom(sockfd, buf, MAXLINE, 0 , ( struct sockaddr * ) & cliaddr, & cliaddr_len);
if (n == - 1 )
perr_exit( " recvfrom error " );
printf( " received from %s at PORT %d\n " ,
inet_ntop(AF_INET, & cliaddr.sin_addr, str, sizeof (str)),
ntohs(cliaddr.sin_port));
for (i = 0 ; i < n; i ++ )
buf[i] = toupper(buf[i]);
n = sendto(sockfd, buf, n, 0 , ( struct sockaddr * ) & cliaddr, sizeof (cliaddr));
if (n == - 1 )
perr_exit( " sendto error " );
}
}
/*
server ---- use UNIX Domain Socket IPC.
*/
#include < stddef.h >
#include < sys / socket.h >
#include < sys / un.h >
#include < sys / stat.h >
#include < errno.h >
#define QLEN 10
/* *
* Create a server endpoint of a connection.
* Returns fd if all OK, <0 on error.
*/
int serv_listen( const char * name)
{
int fd, len, err, rval;
struct sockaddr_un un;
/* create a UNIX domain stream socket */
if ((fd = socket(AF_UNIX, SOCK_STREAM, 0 )) < 0 )
return - 1 ;
unlink(name); /* in case it already exists */
memset( & un, 0 , sizeof (un));
un.sun_family = AF_UNIX;
strcpy(un.sun_path, name);
len = offsetof( struct sockaddr_un, sun_path) + strlen(name);
/* bind the name to the descriptor */
if (bind(fd, ( struct sockaddr * ) & un, len) < 0 ) {
rval = - 2 ;
goto errout;
}
if (listen(fd, QLEN) < 0 ) { /* tell kernel we're a server */
rval = - 3 ;
goto errout;
}
return fd;
errout:
err = errno;
close(fd);
errno = err;
return rval;
}
int serv_accept( int listenfd, uid_t * uidptr)
{
int clifd, len, err, rval;
time_t staletime;
struct sockaddr_un un;
struct stat statbuf;
len = sizeof (un);
if ((clifd = accept(listenfd, ( struct sockaddr * ) & un, & len)) < 0 )
return - 1 ; /* often errno = EINTR, if signal caught */
/* obtain the client's uid from its calling address */
len -= offsetof( struct sockaddr_un, sun_path);
un.sun_path[len] = 0 ;
if (stat(un.sun_path, & statbuf) < 0 ) {
rval = - 2 ;
goto errout;
}
if (S_ISSOCK(statbuf.st_mode) == 0 ) {
rval = - 3 ;
goto errout;
}
if (uidptr != NULL)
* uidptr = statbuf.st_uid; /* return uid of caller */
unlink(un.sun_path);
return clifd;
errout:
err = errno;
close(clifd);
errno = err;
return rval;
}
#include < stddef.h >
#include < sys / socket.h >
#include < sys / un.h >
#include < sys / stat.h >
#include < errno.h >
#define QLEN 10
/* *
* Create a server endpoint of a connection.
* Returns fd if all OK, <0 on error.
*/
int serv_listen( const char * name)
{
int fd, len, err, rval;
struct sockaddr_un un;
/* create a UNIX domain stream socket */
if ((fd = socket(AF_UNIX, SOCK_STREAM, 0 )) < 0 )
return - 1 ;
unlink(name); /* in case it already exists */
memset( & un, 0 , sizeof (un));
un.sun_family = AF_UNIX;
strcpy(un.sun_path, name);
len = offsetof( struct sockaddr_un, sun_path) + strlen(name);
/* bind the name to the descriptor */
if (bind(fd, ( struct sockaddr * ) & un, len) < 0 ) {
rval = - 2 ;
goto errout;
}
if (listen(fd, QLEN) < 0 ) { /* tell kernel we're a server */
rval = - 3 ;
goto errout;
}
return fd;
errout:
err = errno;
close(fd);
errno = err;
return rval;
}
int serv_accept( int listenfd, uid_t * uidptr)
{
int clifd, len, err, rval;
time_t staletime;
struct sockaddr_un un;
struct stat statbuf;
len = sizeof (un);
if ((clifd = accept(listenfd, ( struct sockaddr * ) & un, & len)) < 0 )
return - 1 ; /* often errno = EINTR, if signal caught */
/* obtain the client's uid from its calling address */
len -= offsetof( struct sockaddr_un, sun_path);
un.sun_path[len] = 0 ;
if (stat(un.sun_path, & statbuf) < 0 ) {
rval = - 2 ;
goto errout;
}
if (S_ISSOCK(statbuf.st_mode) == 0 ) {
rval = - 3 ;
goto errout;
}
if (uidptr != NULL)
* uidptr = statbuf.st_uid; /* return uid of caller */
unlink(un.sun_path);
return clifd;
errout:
err = errno;
close(clifd);
errno = err;
return rval;
}
/*
implement concurrent service.
*/
/* #1, use fork(). */
#define MAXLINE 80
#define SERV_PORT 8000
void sig_chld( int signo)
{
pid_t pid;
int status;
pid = wait( & status);
printf( " subprocess %d exit at %d\n " , pid, status);
}
int main( void )
{
struct sockaddr_in servaddr, cliaddr;
socklen_t cliaddr_len;
int listenfd, connfd;
char buf[MAXLINE];
char str[INET_ADDRSTRLEN];
int i, n;
int opt = 1 ;
pid_t pid;
struct sigaction act;
act.sa_handler = sig_chld;
sigemptyset( & act.sa_mask);
act.sa_flags = 0 ;
sigaction(SIGCHLD, & act, NULL);
listenfd = Socket(AF_INET, SOCK_STREAM, 0 );
setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, & opt, sizeof (opt));
bzero( & servaddr, sizeof (servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
servaddr.sin_port = htons(SERV_PORT);
Bind(listenfd, ( struct sockaddr * ) & servaddr, sizeof (servaddr));
Listen(listenfd, 20 );
printf( " Accepting connection\n
"
);
while ( 1 ) {
cliaddr_len = sizeof (cliaddr);
connfd = Accept(listenfd,
( struct sockaddr * ) & cliaddr, & cliaddr_len);
pid = fork();
if (pid == - 1 ) {
perror( " call to fork " );
exit( 1 );
} else if (pid == 0 ) {
close(listenfd);
while ( 1 ) {
n = Read(connfd, buf, MAXLINE);
if (n == 0 ) {
printf( " the client has been closed.\n " );
break ;
}
printf( " received from %s at PORT %d\n " ,
inet_ntop(AF_INET, & cliaddr.sin_addr, str,
sizeof (str)),ntohs(cliaddr.sin_port));
for (i = 0 ; i < n; i ++ )
buf[i] = toupper(buf[i]);
Write(connfd, buf, n);
}
Close(connfd);
exit( 0 );
} else {
close(connfd);
}
}
}
/* #1, use fork(). */
#define MAXLINE 80
#define SERV_PORT 8000
void sig_chld( int signo)
{
pid_t pid;
int status;
pid = wait( & status);
printf( " subprocess %d exit at %d\n " , pid, status);
}
int main( void )
{
struct sockaddr_in servaddr, cliaddr;
socklen_t cliaddr_len;
int listenfd, connfd;
char buf[MAXLINE];
char str[INET_ADDRSTRLEN];
int i, n;
int opt = 1 ;
pid_t pid;
struct sigaction act;
act.sa_handler = sig_chld;
sigemptyset( & act.sa_mask);
act.sa_flags = 0 ;
sigaction(SIGCHLD, & act, NULL);
listenfd = Socket(AF_INET, SOCK_STREAM, 0 );
setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, & opt, sizeof (opt));
bzero( & servaddr, sizeof (servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
servaddr.sin_port = htons(SERV_PORT);
Bind(listenfd, ( struct sockaddr * ) & servaddr, sizeof (servaddr));
Listen(listenfd, 20 );
printf( " Accepting connection
\n
"
);while ( 1 ) {
cliaddr_len = sizeof (cliaddr);
connfd = Accept(listenfd,
( struct sockaddr * ) & cliaddr, & cliaddr_len);
pid = fork();
if (pid == - 1 ) {
perror( " call to fork " );
exit( 1 );
} else if (pid == 0 ) {
close(listenfd);
while ( 1 ) {
n = Read(connfd, buf, MAXLINE);
if (n == 0 ) {
printf( " the client has been closed.\n " );
break ;
}
printf( " received from %s at PORT %d\n " ,
inet_ntop(AF_INET, & cliaddr.sin_addr, str,
sizeof (str)),ntohs(cliaddr.sin_port));
for (i = 0 ; i < n; i ++ )
buf[i] = toupper(buf[i]);
Write(connfd, buf, n);
}
Close(connfd);
exit( 0 );
} else {
close(connfd);
}
}
}
/*
#2, use select().
*/
#define MAXLINE 80
#define SERV_PORT 8000
int main( int argc, char * argv[])
{
int i, maxi, maxfd, listenfd, connfd, sockfd;
int nready, client[FD_SETSIZE];
ssize_t n;
fd_set rset, allset;
char buf[MAXLINE];
char str[INET_ADDRSTRLEN];
socklen_t cliaddr_len;
struct sockaddr_in cliaddr, servaddr;
listenfd = Socket(AF_INET, SOCK_STREAM, 0 );
bzero( & servaddr, sizeof (servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
servaddr.sin_port = htons(SERV_PORT);
Bind(listenfd, ( struct sockaddr * ) & servaddr, sizeof (servaddr));
Listen(listenfd, 20 );
maxfd = listenfd;
maxi = - 1 ;
for (i = 0 ; i < FD_SETSIZE; i ++ )
client[i] = - 1 ;
FD_ZERO( & allset);
FD_SET(listenfd, & allset);
for (;;) {
rset = allset;
nready = select(maxfd + 1 , & rset, NULL, NULL, NULL);
if (nready < 0 )
perr_exit( " select error " );
if (FD_ISSET(listenfd, & rset)) {
cliaddr_len = sizeof (cliaddr);
connfd = Accept(listenfd,
( struct sockaddr * ) & cliaddr, & cliaddr_len);
printf( " received from %s at PORT %d\n " ,
inet_ntop(AF_INET, & cliaddr.sin_addr, str, sizeof (str)),
ntohs(cliaddr.sin_port));
for (i = 0 ; i < FD_SETSIZE; i ++ )
if (client[i] < 0 ) {
client[i] = connfd;
break ;
}
if (i == FD_SETSIZE) {
fputs( " too many clients\n " , stderr);
exit( 1 );
}
FD_SET(connfd, & allset);
if (connfd > maxfd)
maxfd = connfd;
if (i > maxi)
maxi = i;
if ( -- nready <= 0 )
continue ;
}
for (i = 0 ; i <= maxi; i ++ ) {
if ((sockfd = client[i]) < 0 )
continue ;
if (FD_ISSET(sockfd, & rset)) {
if ((n = Read(sockfd, buf, MAXLINE)) == 0 ) {
Close(sockfd);
FD_CLR(sockfd, & allset);
client[i] = - 1 ;
} else {
int j;
for (j = 0 ; j < n; j ++ )
buf[j] = toupper(buf[j]);
Write(sockfd, buf, n);
}
if ( -- nready <= 0 )
break ;
}
}
}
}
#define MAXLINE 80
#define SERV_PORT 8000
int main( int argc, char * argv[])
{
int i, maxi, maxfd, listenfd, connfd, sockfd;
int nready, client[FD_SETSIZE];
ssize_t n;
fd_set rset, allset;
char buf[MAXLINE];
char str[INET_ADDRSTRLEN];
socklen_t cliaddr_len;
struct sockaddr_in cliaddr, servaddr;
listenfd = Socket(AF_INET, SOCK_STREAM, 0 );
bzero( & servaddr, sizeof (servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
servaddr.sin_port = htons(SERV_PORT);
Bind(listenfd, ( struct sockaddr * ) & servaddr, sizeof (servaddr));
Listen(listenfd, 20 );
maxfd = listenfd;
maxi = - 1 ;
for (i = 0 ; i < FD_SETSIZE; i ++ )
client[i] = - 1 ;
FD_ZERO( & allset);
FD_SET(listenfd, & allset);
for (;;) {
rset = allset;
nready = select(maxfd + 1 , & rset, NULL, NULL, NULL);
if (nready < 0 )
perr_exit( " select error " );
if (FD_ISSET(listenfd, & rset)) {
cliaddr_len = sizeof (cliaddr);
connfd = Accept(listenfd,
( struct sockaddr * ) & cliaddr, & cliaddr_len);
printf( " received from %s at PORT %d\n " ,
inet_ntop(AF_INET, & cliaddr.sin_addr, str, sizeof (str)),
ntohs(cliaddr.sin_port));
for (i = 0 ; i < FD_SETSIZE; i ++ )
if (client[i] < 0 ) {
client[i] = connfd;
break ;
}
if (i == FD_SETSIZE) {
fputs( " too many clients\n " , stderr);
exit( 1 );
}
FD_SET(connfd, & allset);
if (connfd > maxfd)
maxfd = connfd;
if (i > maxi)
maxi = i;
if ( -- nready <= 0 )
continue ;
}
for (i = 0 ; i <= maxi; i ++ ) {
if ((sockfd = client[i]) < 0 )
continue ;
if (FD_ISSET(sockfd, & rset)) {
if ((n = Read(sockfd, buf, MAXLINE)) == 0 ) {
Close(sockfd);
FD_CLR(sockfd, & allset);
client[i] = - 1 ;
} else {
int j;
for (j = 0 ; j < n; j ++ )
buf[j] = toupper(buf[j]);
Write(sockfd, buf, n);
}
if ( -- nready <= 0 )
break ;
}
}
}
}