C|网络编程-C语言实现多进程并发服务器
在Linux操作系统下，服务器通过fork()复制已调用的进程来创建子进程，以此来实现多进程并发服务器
功能：客户端发送任意字符串，服务器端将字符串小写转大写toupper();
并返回给客户端，客户端将结果打印在屏幕上。
C/S模型：
server.c 7 步：
socket();
bind();
listen();
accept();
read();
write();
close();
client.c 7 步：
socket();
connect()
fgets();
write();
写给服务器
read();
从服务器读
write(STDOUT_FILENO, buf, n);
close();
client.c
#include
#include
#include
#include
#include #include "wrap.h"#define SERV_IP "127.0.0.1"
#define SERV_PORT 8000int main(void)
{
int sfd, len;
struct sockaddr_in serv_addr;
char buf[BUFSIZ];
sfd = Socket(AF_INET, SOCK_STREAM, 0);
bzero(&serv_addr, sizeof(serv_addr));
serv_addr.sin_family = AF_INET;
inet_pton(AF_INET, SERV_IP, &serv_addr.sin_addr.s_addr);
serv_addr.sin_port = htons(SERV_PORT);
Connect(sfd, (struct sockaddr *)&serv_addr, sizeof(serv_addr));
while (1) {
fgets(buf, sizeof(buf), stdin);
int r = Write(sfd, buf, strlen(buf));
//printf("Write r === %d\n", r);
len = Read(sfd, buf, sizeof(buf));
//printf("Read len == %d\n", len);
Write(STDOUT_FILENO, buf, len);
}Close(sfd);
return 0;
} server.c
#include
#include
#include
#include
#include
#include
#include
#include #include "wrap.h"#define MAXLINE 8192
#define SERV_PORT 8000void do_sigchild(int num)
{
while (waitpid(0, NULL, WNOHANG) > 0)
;
}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;
pid_t pid;
struct sigaction newact;
newact.sa_handler = do_sigchild;
sigemptyset(&newact.sa_mask);
newact.sa_flags = 0;
sigaction(SIGCHLD, &newact, NULL);
listenfd = Socket(AF_INET, SOCK_STREAM, 0);
int opt = 1;
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 connections ...\n");
while (1) {
cliaddr_len = sizeof(cliaddr);
connfd = Accept(listenfd, (struct sockaddr *)&cliaddr, &cliaddr_len);
pid = fork();
if (pid == 0) {
Close(listenfd);
while (1) {
n = Read(connfd, buf, MAXLINE);
if (n == 0) {
printf("the other side 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(STDOUT_FILENO, buf, n);
Write(connfd, buf, n);
}
Close(connfd);
return 0;
} else if (pid > 0) {
Close(connfd);
}else
perr_exit("fork");
}
return 0;
} 另外，我自主封装了wrap库文件，用于在函数内部处理出错问题，并且仅使函数的首字母大写，这样在Linux操作系统vim的NORMAL模式下按K仍能进入帮助文档。
wrap.h
#ifndef __WRAP_H_
#define __WRAP_H_void perr_exit(const char *s);
int Accept(int fd, struct sockaddr *sa, socklen_t *salenptr);
int Bind(int fd, const struct sockaddr *sa, socklen_t salen);
int Connect(int fd, const struct sockaddr *sa, socklen_t salen);
int Listen(int fd, int backlog);
int Socket(int family, int type, int protocol);
ssize_t Read(int fd, void *ptr, size_t nbytes);
ssize_t Write(int fd, const void *ptr, size_t nbytes);
int Close(int fd);
ssize_t Readn(int fd, void *vptr, size_t n);
ssize_t Writen(int fd, const void *vptr, size_t n);
ssize_t my_read(int fd, char *ptr);
ssize_t Readline(int fd, void *vptr, size_t maxlen);
#endif【C|网络编程-C语言实现多进程并发服务器】wrap.c
#include
#include
#include
#include
#include void perr_exit(const char *s)
{
perror(s);
exit(-1);
}int Accept(int fd, struct sockaddr *sa, socklen_t *salenptr)
{
int n;
again:
if ((n = accept(fd, sa, salenptr)) < 0) {
if ((errno == ECONNABORTED) || (errno == EINTR))
goto again;
else
perr_exit("accept error");
}
return n;
}int Bind(int fd, const struct sockaddr *sa, socklen_t salen)
{
int n;
if ((n = bind(fd, sa, salen)) < 0)
perr_exit("bind error");
return n;
}int Connect(int fd, const struct sockaddr *sa, socklen_t salen)
{
int n;
if ((n = connect(fd, sa, salen)) < 0)
perr_exit("connect error");
return n;
}int Listen(int fd, int backlog)
{
int n;
if ((n = listen(fd, backlog)) < 0)
perr_exit("listen error");
return n;
}int Socket(int family, int type, int protocol)
{
int n;
if ((n = socket(family, type, protocol)) < 0)
perr_exit("socket error");
return n;
}ssize_t Read(int fd, void *ptr, size_t nbytes)
{
ssize_t n;
again:
if ( (n = read(fd, ptr, nbytes)) == -1) {
if (errno == EINTR)
goto again;
else
return -1;
}
return n;
}ssize_t Write(int fd, const void *ptr, size_t nbytes)
{
ssize_t n;
again:
if ( (n = write(fd, ptr, nbytes)) == -1) {
if (errno == EINTR)
goto again;
else
return -1;
}
return n;
}int Close(int fd)
{
int n;
if ((n = close(fd)) == -1)
perr_exit("close error");
return n;
}/*?????‰: ?o”èˉ￥èˉ???–????-—è????°*/
ssize_t Readn(int fd, void *vptr, size_t n)
{
size_tnleft;
//usigned int ?‰??????aèˉ???–????-—è????°
ssize_t nread;
//int ???é?…èˉ???°????-—è????°
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;
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;
else
return -1;
}nleft -= nwritten;
ptr += nwritten;
}
return n;
}static ssize_t my_read(int fd, char *ptr)
{
static int read_cnt;
static char *read_ptr;
static char read_buf[100];
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;
charc, *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;
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