我正在练习echo服务器/客户端，并且遇到了一些问题。
这是头文件名myheader.h
#include <arpa/inet.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include <signal.h>
typedef void Sigfunc(int);
static int read_cnt;
static char *read_ptr;
static char read_buf[1024];
ssize_t
readn(int fd, void *vptr, size_t n)
{
size_t nleft;
ssize_t nread;
char *ptr;
ptr=vptr;
nleft=n;
while(nleft>0)
{
if((nread=read(fd, ptr, nleft))<0)
{
if(errno==EINTR)
nread=0;
else
return -1;
}
else if(nread==0)
break; /* End of File reached */
nleft-=nread;
ptr+=nread;
}
return (n-nleft);
}
ssize_t
writen(int fd, const void *vptr, size_t n)
{
size_t nleft;
ssize_t nwritten;
const char *ptr;
ptr=vptr;
nleft=n;
while(nleft>0)
{
if((nwritten=write(fd, ptr, nleft))<=0)
{
if(nwritten<0 && errno==EINTR)
nwritten=0; /* and call write() again */
else
return -1; /* error */
}
nleft-=nwritten;
ptr+=nwritten;
}
return n;
}
static ssize_t
my_read(int fd, char *ptr)
{
if(read_cnt<=0)
{
again:
if((read_cnt=read(fd, read_buf, sizeof(read_buf)))<0)
{
if(errno==EINTR)
goto again;
return -1;
}
else if(read_cnt==0)
return 0;
read_ptr=read_buf;
}
read_cnt--;
*ptr=*read_ptr++;
return 1;
}
ssize_t
Readline(int fd, void *vptr, size_t maxlen)
{
ssize_t n, rc;
char c, *ptr;
ptr=vptr;
for(n=1; n<maxlen; n++)
{
if((rc=my_read(fd, &c))==1)
{
*ptr++=c;
if(c=='\n')
break;
}
else if(rc==0)
{
*ptr=0;
return (n-1);
}
else
return -1;
}
*ptr=0;
return n;
}
void
str_echo(int sockfd)
{
ssize_t n;
char buf[1024];
again:
while((n=read(sockfd, buf, 1024))>0)
writen(sockfd, buf, n);
if(n<0 && errno==EINTR)
goto again;
else if(n<0)
{
printf("str_echo: read error");
exit(1);
}
}
void
str_cli(FILE *fp, int sockfd)
{
char sendline[1024], recvline[1024];
while(fgets(sendline, 1024, fp)!=NULL)
{
//writen(sockfd, sendline, strlen(sendline));
writen(sockfd, sendline, 1);
sleep(1000);
writen(sockfd, sendline+1, strlen(sendline)-1);
if(Readline(sockfd, recvline, 1024)==0)
{
printf("str_cli: server terminated prematurely");
}
fputs(recvline, stdout);
}
}
Sigfunc*
Signal(int signo, Sigfunc *func)
{
struct sigaction act, oact;
act.sa_handler=func;
sigemptyset(&act.sa_mask);
act.sa_flags=0;
if(signo==SIGALRM)
{
#ifdef SA_INTERRUPT
act.sa_flags |=SA_INTERRUPT;
#endif
}
else
{
#ifdef SA_RESTART
act.sa_flags |=SA_RESTART;
#endif
}
if(sigaction(signo, &act, &oact)<0)
return SIG_ERR;
return oact.sa_handler;
}
这是echo客户端源代码：
#include "myheader.h"
#include <sys/socket.h>
#include <netinet/in.h>
int
main(int argc, char** argv)
{
struct sockaddr_in servaddr;
int sockfd;
sockfd=socket(AF_INET,SOCK_STREAM, 0);
bzero(&servaddr, sizeof(servaddr));
servaddr.sin_family=AF_INET;
servaddr.sin_port=htons(9877);
inet_pton(AF_INET, argv[1], &servaddr.sin_addr);
connect(sockfd, (struct sockaddr*)&servaddr, sizeof(servaddr));
str_cli(stdin, sockfd);
exit(0);
}
这是echo服务器代码：
#include "myheader.h"
#include <signal.h>
void
sig_chld(int signo)
{
pid_t pid;
int status;
while((pid=waitpid(-1, &status, WNOHANG))>0)
printf("child %d terminated\n", pid);
return;
}
int
main(int argc, char** argv)
{
int listenfd, connfd;
pid_t childpid;
socklen_t clilen;
struct sockaddr_in cliaddr, servaddr;
listenfd=socket(AF_INET, SOCK_STREAM, 0);
bzero(&servaddr, sizeof(servaddr));
servaddr.sin_family=AF_INET;
servaddr.sin_port=htons(9877);
servaddr.sin_addr.s_addr=htonl(INADDR_ANY);
bind(listenfd, (struct sockaddr*)&servaddr, sizeof(servaddr));
listen(listenfd, 5);
signal(SIGCHLD, sig_chld);
for(;;)
{
clilen=sizeof(cliaddr);
if((connfd=accept(listenfd, (struct sockaddr*)&cliaddr, &clilen))<0)
{
if(errno=EINTR)
continue;
else
{
printf("accpet error\n");
exit(1);
}
}
if((childpid=fork())==0)
{
close(listenfd);
str_echo(connfd);
exit(0);
}
close(connfd);
}
}
所以当我连接到echo服务器时，我输入的消息就像＆＃39; hello guys＆＃39;
然后，它应该首先将数据发送到服务器1字节，这里是h。
然后它睡了10秒钟。然后应发送ello guys。
但是，当我输入“你好”的时候。我得到了'你好'的家伙＆＃39;从服务器立即。为什么我立即得到完整的消息，而不是分开？
这是我收到的TCPDUMP :(我发送hello）
21:17:27.798745 IP localhost.47761 > localhost.9877: Flags [S], seq 319562030, win 43690, options [mss 65495,sackOK,TS val 1147465 ecr 0,nop,wscale 10], length 0
21:17:27.798762 IP localhost.9877 > localhost.47761: Flags [S.], seq 3488701479, ack 319562031, win 43690, options [mss 65495,sackOK,TS val 1147465 ecr 1147465,nop,wscale 10], length 0
21:17:27.798779 IP localhost.47761 > localhost.9877: Flags [.], ack 1, win 43, options [nop,nop,TS val 1147465 ecr 1147465], length 0
21:17:58.130012 IP localhost.47761 > localhost.9877: Flags [P.], seq 1:7, ack 1, win 43, options [nop,nop,TS val 1155048 ecr 1147465], length 6
21:17:58.130065 IP localhost.9877 > localhost.47761: Flags [.], ack 7, win 43, options [nop,nop,TS val 1155048 ecr 1155048], length 0
21:17:58.130093 IP localhost.9877 > localhost.47761: Flags [P.], seq 1:7, ack 7, win 43, options [nop,nop,TS val 1155048 ecr 1155048], length 6
21:17:58.130114 IP localhost.47761 > localhost.9877: Flags [.], ack 7, win 43, options [nop,nop,TS val 1155048 ecr 1155048], length 0