如何在线程间共享变量？
How to share variables among threads?
我正在开发一个允许服务器交换消息的服务器-客户端项目
与客户单独。但是，我必须修改服务器，以便在服务器发送消息时将消息发送给所有连接的客户端。
我知道这涉及在线程之间共享变量，但我对如何去做感到困惑？
任何 tips/guidence 将不胜感激！
服务器代码：
#include<stdio.h>
#include<string.h> //strlen
#include<stdlib.h> //strlen
#include<sys/socket.h>
#include<arpa/inet.h> //inet_addr
#include<unistd.h> //write
#include<pthread.h> //for threading , link with lpthread
#define MAX 80
#define PORT 6543
#define SA struct sockaddr
// Function designed for chat between client and server.
void join( pthread_t *thread_id)
{
if(!pthread_join( *thread_id , NULL))
printf("thread %ld complted\n",*thread_id);
pthread_exit(0);//to exit the current thread
}
void func(int *sockfd)
{
char buff[MAX];
int n;
// infinite loop for chat
for (;;) {
bzero(buff, MAX);
// read the message from client and copy it in buffer
read(*sockfd, buff, sizeof(buff));
// print buffer which contains the client contents
printf("From client: %s\t To client : ", buff);
bzero(buff, MAX);
n = 0;
// copy server message in the buffer
while ((buff[n++] = getchar()) != '\n');
// and send that buffer to client
write(*sockfd, buff, sizeof(buff));
// if msg contains "Exit" then server exit and chat ended.
if (strncmp("exit", buff, 4) == 0) {
printf("Server Exit...\n");
break;
}
}
}
// Driver function
int main()
{
int sockfd, connfd, len;
struct sockaddr_in servaddr, cli;
pthread_t thread_id,jointhread_id;
// socket create and verification
sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (sockfd == -1) {
printf("socket creation failed...\n");
exit(0);
}
else
printf("Socket successfully created..\n");
bzero(&servaddr, sizeof(servaddr));
// assign IP, PORT
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = INADDR_ANY;
servaddr.sin_port = htons(PORT);
// Binding newly created socket to given IP and verification
if ((bind(sockfd, (SA*)&servaddr, sizeof(servaddr))) != 0) {
printf("socket bind failed...\n");
exit(0);
}
else
printf("Socket successfully binded..\n");
// Now server is ready to listen and verification
if ((listen(sockfd, 5)) != 0) {
printf("Listen failed...\n");
exit(0);
}
else
printf("Server listening..\n");
len = sizeof(cli);
// Accept the data packet from client and verification
while(connfd = accept(sockfd, (SA*)&cli, &len))
{
if (connfd < 0) {
printf("server acccept failed...\n");
exit(0);
}
else
printf("server acccept the client..%d.\n",connfd);
if( pthread_create( &thread_id , NULL , func , (void*) &connfd) < 0)
{
perror("could not create thread");
return 1;
}
if( pthread_create( &jointhread_id , NULL , join , (void*) &thread_id) < 0)
{
perror("could not create thread");
return 1;
}
}
// After chatting close the socket
close(sockfd);
}
不幸的是，有很多错误...
错误的线程函数原型
我的热门评论中提到的 connfd 竞争条件（将 connfd 作为指针传递给 func）。
执行 getchar 会破坏 sockfd
读取的消息数据
我在下面制作了一个版本来说明这一点。
但是，要真正使代码更接近您所述目的所需的代码，需要进行大量重构。下面还有第二个版本说明了我对此的看法。
这是一个带注释的版本，显示了错误和一些修复[主要是为了让它干净地编译所花费的时间]。
它用 #if ORIG 包装原始代码，用 #if FIX 包装新代码，每个地方都有关于它修复的错误的评论
#include <stdio.h>
#include <string.h> // strlen
#include <stdlib.h> // strlen
#include <sys/socket.h>
#include <arpa/inet.h> // inet_addr
#include <unistd.h> // write
#include <pthread.h> // for threading , link with lpthread
#define MAX 80
#define PORT 6543
#define SA struct sockaddr
#define ORIG 0
#define FIX 1
// Function designed for chat between client and server.
// NOTE/BUG -- the main thread has to join the thread
#if ORIG
void
join(pthread_t *thread_id)
{
if (!pthread_join(*thread_id, NULL))
printf("thread %ld complted\n", *thread_id);
// to exit the current thread
pthread_exit(0);
}
#endif
// NOTE/BUG: this is the _wrong_ signature for a thread function
#if ORIG
void
func(int *sockfd)
#else
void *
func(void *ptr)
#endif
{
#if FIX
int sockfd = (long) ptr;
#endif
char buff[MAX];
int n;
// infinite loop for chat
for (;;) {
bzero(buff, MAX);
// read the message from client and copy it in buffer
// NOTE/BUG: this has a race condition
// NOTE/BUG: we need the actual length
#if ORIG
read(*sockfd, buff, sizeof(buff));
#else
int rlen = read(sockfd, buff, sizeof(buff));
#endif
// print buffer which contains the client contents
printf("From client: %s\t To client : ", buff);
bzero(buff, MAX);
// copy server message in the buffer
// NOTE/BUG: this is destroying the data that was
#if ORIG
n = 0;
while ((buff[n++] = getchar()) != '\n');
#endif
// and send that buffer to client
#if ORIG
write(*sockfd, buff, sizeof(buff));
#else
write(sockfd, buff, rlen);
#endif
// if msg contains "Exit" then server exit and chat ended.
if (strncmp("exit", buff, 4) == 0) {
printf("Server Exit...\n");
break;
}
}
// NOTE/BUG: we must return the error code
#if FIX
return (void *) 0;
#endif
}
// Driver function
int
main()
{
int sockfd, connfd, len;
struct sockaddr_in servaddr, cli;
pthread_t thread_id, jointhread_id;
// socket create and verification
sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (sockfd == -1) {
printf("socket creation failed...\n");
exit(0);
}
else
printf("Socket successfully created..\n");
// assign IP, PORT
bzero(&servaddr, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = INADDR_ANY;
servaddr.sin_port = htons(PORT);
// Binding newly created socket to given IP and verification
if ((bind(sockfd, (SA *) & servaddr, sizeof(servaddr))) != 0) {
printf("socket bind failed...\n");
exit(0);
}
else
printf("Socket successfully binded..\n");
// Now server is ready to listen and verification
if ((listen(sockfd, 5)) != 0) {
printf("Listen failed...\n");
exit(0);
}
else
printf("Server listening..\n");
// Accept the data packet from client and verification
len = sizeof(cli);
// NOTE/BUG: connfd can be zero for a valid connection
#if ORIG
while (connfd = accept(sockfd, (SA *) &cli, &len)) {
#else
while (1) {
connfd = accept(sockfd, (SA *) &cli, &len);
#endif
if (connfd < 0) {
printf("server acccept failed...\n");
exit(0);
}
else
printf("server acccept the client..%d.\n", connfd);
#if ORIG
if (pthread_create(&thread_id, NULL, func, (void *) &connfd) < 0) {
perror("could not create thread");
return 1;
}
#else
if (pthread_create(&thread_id, NULL, func, (void *) ((long) connfd)) < 0) {
perror("could not create thread");
return 1;
}
#endif
// NOTE/BUG -- creating a separate thread just to join the above thread does
// not help
#if ORIG
if (pthread_create(&jointhread_id, NULL, join, (void *) &thread_id) < 0) {
perror("could not create thread");
return 1;
}
#endif
}
// After chatting close the socket
close(sockfd);
return 0;
}
这是一个重构版本，它实现了您想要的多客户端消息回显。
它使用 per-thread 任务块来控制事物。每个客户端收到一条消息后，会将其发送给所有其他客户端。
它还使用互斥体进行了一些线程间锁定。
让一个给定的客户端线程完成对其他客户端的所有回显只是一种方法。还有其他的（例如，所有客户端线程将消息排队到 master/main 线程并且 它 执行回显）
这更接近了，但是在 func 到 receive/send 客户端消息中，您还有更多工作要做。
无论如何，这是代码：
#include <stdio.h>
#include <string.h> // strlen
#include <stdlib.h> // strlen
#include <sys/socket.h>
#include <arpa/inet.h> // inet_addr
#include <unistd.h> // write
#include <pthread.h> // for threading , link with lpthread
#define MAX 80
#define PORT 6543
#define SA struct sockaddr
#define ORIG 0
#define FIX 1
enum {
TSKSTATE_IDLE, // task slot free/available
TSKSTATE_PENDING, // task is being created
TSKSTATE_RUNNING, // task is alive and running
TSKSTATE_DONE // task has completed (but not reaped)
};
typedef struct tsk tsk_t;
struct tsk {
tsk_t *tsk_next; // chain pointer
pthread_t tsk_tid; // thread id
long tsk_xid; // sequential task id
int tsk_sockfd; // client socket descriptor
int tsk_state; // current task state
pthread_mutex_t tsk_mutex; // per-thread mutex
void *tsk_rtn; // thread's return value
};
// NOTE: using an array obviates the need for a master lock if we used a
// linked list here instead -- by passing TSKMAX to listen below [in main],
// we guarantee that main can always find a free task slot when it needs one
#define TSKMAX 5
tsk_t tsklist[TSKMAX]; // active task list
#define TSKFORALL(_tsk) \
_tsk = &tsklist[0]; _tsk < &tsklist[TSKMAX]; ++_tsk
long tskxid; // sequential task id
__thread tsk_t *tskcur; // current thread's tsk block
pthread_mutex_t master_lock = PTHREAD_MUTEX_INITIALIZER;
// lockall -- lock all threads
void
lockall(void)
{
pthread_mutex_lock(&master_lock);
}
// unlockall -- lock all threads
void
unlockall(void)
{
pthread_mutex_unlock(&master_lock);
}
// tsklock -- lock single thread
void
tsklock(tsk_t *tsk)
{
pthread_mutex_lock(&tsk->tsk_mutex);
}
// tskunlock -- unlock single thread
void
tskunlock(tsk_t *tsk)
{
pthread_mutex_unlock(&tsk->tsk_mutex);
}
// tskreapall -- release all completed threads
void
tskreapall(void)
{
tsk_t *tsk;
lockall();
for (TSKFORALL(tsk)) {
tsklock(tsk);
if (tsk->tsk_state == TSKSTATE_DONE) {
pthread_join(tsk->tsk_tid,&tsk->tsk_rtn);
tsk->tsk_state = TSKSTATE_IDLE;
}
tskunlock(tsk);
}
}
// tsksendall -- send message to all other clients
void
tsksendall(char *msg,int len)
{
tsk_t *tsk;
lockall();
for (TSKFORALL(tsk)) {
if (tsk == tskcur)
continue;
tsklock(tsk);
if (tsk->tsk_state == TSKSTATE_RUNNING)
write(tsk->tsk_sockfd,msg,len);
tskunlock(tsk);
}
}
void *
func(void *ptr)
{
tskcur = ptr;
char buff[MAX];
#if ORIG
int n;
#endif
tsklock(tskcur);
tskcur->tsk_state = TSKSTATE_RUNNING;
tskunlock(tskcur);
// infinite loop for chat
// NOTE: this loop still needs work ...
for (;;) {
bzero(buff, MAX);
// read the message from client and copy it in buffer
int rlen = read(tskcur->tsk_sockfd, buff, sizeof(buff));
// print buffer which contains the client contents
printf("From client: %s\t To client : ", buff);
bzero(buff, MAX);
// copy server message in the buffer
// NOTE/BUG: this is destroying the data that was
#if ORIG
n = 0;
while ((buff[n++] = getchar()) != '\n');
#endif
// and send that buffer to client
write(tskcur->tsk_sockfd, buff, rlen);
// if msg contains "Exit" then server exit and chat ended.
if (strncmp("exit", buff, 4) == 0) {
printf("Server Exit...\n");
break;
}
// echo message to all other clients
tsksendall(buff,rlen);
}
tsklock(tskcur);
tskcur->tsk_state = TSKSTATE_DONE;
close(tskcur->tsk_sockfd);
tskcur->tsk_sockfd = -1;
tskunlock(tskcur);
return (void *) 0;
}
// Driver function
int
main(void)
{
int sockfd, connfd;
socklen_t len;
struct sockaddr_in servaddr, cli;
int state;
tsk_t *tsktry;
tsk_t *tsknew;
// socket create and verification
sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (sockfd == -1) {
printf("socket creation failed...\n");
exit(0);
}
else
printf("Socket successfully created..\n");
// assign IP, PORT
bzero(&servaddr, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = INADDR_ANY;
servaddr.sin_port = htons(PORT);
// Binding newly created socket to given IP and verification
if ((bind(sockfd, (SA *) & servaddr, sizeof(servaddr))) != 0) {
printf("socket bind failed...\n");
exit(0);
}
else
printf("Socket successfully binded..\n");
// Now server is ready to listen and verification
if ((listen(sockfd, TSKMAX)) != 0) {
printf("Listen failed...\n");
exit(0);
}
else
printf("Server listening..\n");
// Accept the data packet from client and verification
len = sizeof(cli);
for (TSKFORALL(tsktry)) {
pthread_mutex_init(&tsktry->tsk_mutex,NULL);
tsktry->tsk_state = TSKSTATE_IDLE;
}
while (1) {
connfd = accept(sockfd, (SA *) &cli, &len);
if (connfd < 0) {
printf("server acccept failed...\n");
exit(0);
}
else
printf("server acccept the client..%d.\n", connfd);
// reap all completed threads
tskreapall();
// find an idle slot
tsknew = NULL;
for (TSKFORALL(tsktry)) {
tsklock(tsktry);
state = tsktry->tsk_state;
if (state == TSKSTATE_IDLE) {
tsknew = tsktry;
tsknew->tsk_state = TSKSTATE_PENDING;
}
tskunlock(tsktry);
if (tsknew != NULL)
break;
}
tsknew->tsk_xid = ++tskxid;
tsknew->tsk_sockfd = connfd;
if (pthread_create(&tsknew->tsk_tid, NULL, func, tsknew) < 0) {
perror("could not create thread");
return 1;
}
}
// After chatting close the socket
close(sockfd);
return 0;
}
我正在开发一个允许服务器交换消息的服务器-客户端项目 与客户单独。但是，我必须修改服务器，以便在服务器发送消息时将消息发送给所有连接的客户端。
我知道这涉及在线程之间共享变量，但我对如何去做感到困惑？
任何 tips/guidence 将不胜感激！
服务器代码：
#include<stdio.h>
#include<string.h> //strlen
#include<stdlib.h> //strlen
#include<sys/socket.h>
#include<arpa/inet.h> //inet_addr
#include<unistd.h> //write
#include<pthread.h> //for threading , link with lpthread
#define MAX 80
#define PORT 6543
#define SA struct sockaddr
// Function designed for chat between client and server.
void join( pthread_t *thread_id)
{
if(!pthread_join( *thread_id , NULL))
printf("thread %ld complted\n",*thread_id);
pthread_exit(0);//to exit the current thread
}
void func(int *sockfd)
{
char buff[MAX];
int n;
// infinite loop for chat
for (;;) {
bzero(buff, MAX);
// read the message from client and copy it in buffer
read(*sockfd, buff, sizeof(buff));
// print buffer which contains the client contents
printf("From client: %s\t To client : ", buff);
bzero(buff, MAX);
n = 0;
// copy server message in the buffer
while ((buff[n++] = getchar()) != '\n');
// and send that buffer to client
write(*sockfd, buff, sizeof(buff));
// if msg contains "Exit" then server exit and chat ended.
if (strncmp("exit", buff, 4) == 0) {
printf("Server Exit...\n");
break;
}
}
}
// Driver function
int main()
{
int sockfd, connfd, len;
struct sockaddr_in servaddr, cli;
pthread_t thread_id,jointhread_id;
// socket create and verification
sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (sockfd == -1) {
printf("socket creation failed...\n");
exit(0);
}
else
printf("Socket successfully created..\n");
bzero(&servaddr, sizeof(servaddr));
// assign IP, PORT
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = INADDR_ANY;
servaddr.sin_port = htons(PORT);
// Binding newly created socket to given IP and verification
if ((bind(sockfd, (SA*)&servaddr, sizeof(servaddr))) != 0) {
printf("socket bind failed...\n");
exit(0);
}
else
printf("Socket successfully binded..\n");
// Now server is ready to listen and verification
if ((listen(sockfd, 5)) != 0) {
printf("Listen failed...\n");
exit(0);
}
else
printf("Server listening..\n");
len = sizeof(cli);
// Accept the data packet from client and verification
while(connfd = accept(sockfd, (SA*)&cli, &len))
{
if (connfd < 0) {
printf("server acccept failed...\n");
exit(0);
}
else
printf("server acccept the client..%d.\n",connfd);
if( pthread_create( &thread_id , NULL , func , (void*) &connfd) < 0)
{
perror("could not create thread");
return 1;
}
if( pthread_create( &jointhread_id , NULL , join , (void*) &thread_id) < 0)
{
perror("could not create thread");
return 1;
}
}
// After chatting close the socket
close(sockfd);
}
不幸的是，有很多错误...
错误的线程函数原型
我的热门评论中提到的 connfd 竞争条件（将 connfd 作为指针传递给 func）。
执行 getchar 会破坏 sockfd
我在下面制作了一个版本来说明这一点。
但是，要真正使代码更接近您所述目的所需的代码，需要进行大量重构。下面还有第二个版本说明了我对此的看法。
这是一个带注释的版本，显示了错误和一些修复[主要是为了让它干净地编译所花费的时间]。
它用 #if ORIG 包装原始代码，用 #if FIX 包装新代码，每个地方都有关于它修复的错误的评论
#include <stdio.h>
#include <string.h> // strlen
#include <stdlib.h> // strlen
#include <sys/socket.h>
#include <arpa/inet.h> // inet_addr
#include <unistd.h> // write
#include <pthread.h> // for threading , link with lpthread
#define MAX 80
#define PORT 6543
#define SA struct sockaddr
#define ORIG 0
#define FIX 1
// Function designed for chat between client and server.
// NOTE/BUG -- the main thread has to join the thread
#if ORIG
void
join(pthread_t *thread_id)
{
if (!pthread_join(*thread_id, NULL))
printf("thread %ld complted\n", *thread_id);
// to exit the current thread
pthread_exit(0);
}
#endif
// NOTE/BUG: this is the _wrong_ signature for a thread function
#if ORIG
void
func(int *sockfd)
#else
void *
func(void *ptr)
#endif
{
#if FIX
int sockfd = (long) ptr;
#endif
char buff[MAX];
int n;
// infinite loop for chat
for (;;) {
bzero(buff, MAX);
// read the message from client and copy it in buffer
// NOTE/BUG: this has a race condition
// NOTE/BUG: we need the actual length
#if ORIG
read(*sockfd, buff, sizeof(buff));
#else
int rlen = read(sockfd, buff, sizeof(buff));
#endif
// print buffer which contains the client contents
printf("From client: %s\t To client : ", buff);
bzero(buff, MAX);
// copy server message in the buffer
// NOTE/BUG: this is destroying the data that was
#if ORIG
n = 0;
while ((buff[n++] = getchar()) != '\n');
#endif
// and send that buffer to client
#if ORIG
write(*sockfd, buff, sizeof(buff));
#else
write(sockfd, buff, rlen);
#endif
// if msg contains "Exit" then server exit and chat ended.
if (strncmp("exit", buff, 4) == 0) {
printf("Server Exit...\n");
break;
}
}
// NOTE/BUG: we must return the error code
#if FIX
return (void *) 0;
#endif
}
// Driver function
int
main()
{
int sockfd, connfd, len;
struct sockaddr_in servaddr, cli;
pthread_t thread_id, jointhread_id;
// socket create and verification
sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (sockfd == -1) {
printf("socket creation failed...\n");
exit(0);
}
else
printf("Socket successfully created..\n");
// assign IP, PORT
bzero(&servaddr, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = INADDR_ANY;
servaddr.sin_port = htons(PORT);
// Binding newly created socket to given IP and verification
if ((bind(sockfd, (SA *) & servaddr, sizeof(servaddr))) != 0) {
printf("socket bind failed...\n");
exit(0);
}
else
printf("Socket successfully binded..\n");
// Now server is ready to listen and verification
if ((listen(sockfd, 5)) != 0) {
printf("Listen failed...\n");
exit(0);
}
else
printf("Server listening..\n");
// Accept the data packet from client and verification
len = sizeof(cli);
// NOTE/BUG: connfd can be zero for a valid connection
#if ORIG
while (connfd = accept(sockfd, (SA *) &cli, &len)) {
#else
while (1) {
connfd = accept(sockfd, (SA *) &cli, &len);
#endif
if (connfd < 0) {
printf("server acccept failed...\n");
exit(0);
}
else
printf("server acccept the client..%d.\n", connfd);
#if ORIG
if (pthread_create(&thread_id, NULL, func, (void *) &connfd) < 0) {
perror("could not create thread");
return 1;
}
#else
if (pthread_create(&thread_id, NULL, func, (void *) ((long) connfd)) < 0) {
perror("could not create thread");
return 1;
}
#endif
// NOTE/BUG -- creating a separate thread just to join the above thread does
// not help
#if ORIG
if (pthread_create(&jointhread_id, NULL, join, (void *) &thread_id) < 0) {
perror("could not create thread");
return 1;
}
#endif
}
// After chatting close the socket
close(sockfd);
return 0;
}
这是一个重构版本，它实现了您想要的多客户端消息回显。
它使用 per-thread 任务块来控制事物。每个客户端收到一条消息后，会将其发送给所有其他客户端。
它还使用互斥体进行了一些线程间锁定。
让一个给定的客户端线程完成对其他客户端的所有回显只是一种方法。还有其他的（例如，所有客户端线程将消息排队到 master/main 线程并且 它 执行回显）
这更接近了，但是在 func 到 receive/send 客户端消息中，您还有更多工作要做。
无论如何，这是代码：
#include <stdio.h>
#include <string.h> // strlen
#include <stdlib.h> // strlen
#include <sys/socket.h>
#include <arpa/inet.h> // inet_addr
#include <unistd.h> // write
#include <pthread.h> // for threading , link with lpthread
#define MAX 80
#define PORT 6543
#define SA struct sockaddr
#define ORIG 0
#define FIX 1
enum {
TSKSTATE_IDLE, // task slot free/available
TSKSTATE_PENDING, // task is being created
TSKSTATE_RUNNING, // task is alive and running
TSKSTATE_DONE // task has completed (but not reaped)
};
typedef struct tsk tsk_t;
struct tsk {
tsk_t *tsk_next; // chain pointer
pthread_t tsk_tid; // thread id
long tsk_xid; // sequential task id
int tsk_sockfd; // client socket descriptor
int tsk_state; // current task state
pthread_mutex_t tsk_mutex; // per-thread mutex
void *tsk_rtn; // thread's return value
};
// NOTE: using an array obviates the need for a master lock if we used a
// linked list here instead -- by passing TSKMAX to listen below [in main],
// we guarantee that main can always find a free task slot when it needs one
#define TSKMAX 5
tsk_t tsklist[TSKMAX]; // active task list
#define TSKFORALL(_tsk) \
_tsk = &tsklist[0]; _tsk < &tsklist[TSKMAX]; ++_tsk
long tskxid; // sequential task id
__thread tsk_t *tskcur; // current thread's tsk block
pthread_mutex_t master_lock = PTHREAD_MUTEX_INITIALIZER;
// lockall -- lock all threads
void
lockall(void)
{
pthread_mutex_lock(&master_lock);
}
// unlockall -- lock all threads
void
unlockall(void)
{
pthread_mutex_unlock(&master_lock);
}
// tsklock -- lock single thread
void
tsklock(tsk_t *tsk)
{
pthread_mutex_lock(&tsk->tsk_mutex);
}
// tskunlock -- unlock single thread
void
tskunlock(tsk_t *tsk)
{
pthread_mutex_unlock(&tsk->tsk_mutex);
}
// tskreapall -- release all completed threads
void
tskreapall(void)
{
tsk_t *tsk;
lockall();
for (TSKFORALL(tsk)) {
tsklock(tsk);
if (tsk->tsk_state == TSKSTATE_DONE) {
pthread_join(tsk->tsk_tid,&tsk->tsk_rtn);
tsk->tsk_state = TSKSTATE_IDLE;
}
tskunlock(tsk);
}
}
// tsksendall -- send message to all other clients
void
tsksendall(char *msg,int len)
{
tsk_t *tsk;
lockall();
for (TSKFORALL(tsk)) {
if (tsk == tskcur)
continue;
tsklock(tsk);
if (tsk->tsk_state == TSKSTATE_RUNNING)
write(tsk->tsk_sockfd,msg,len);
tskunlock(tsk);
}
}
void *
func(void *ptr)
{
tskcur = ptr;
char buff[MAX];
#if ORIG
int n;
#endif
tsklock(tskcur);
tskcur->tsk_state = TSKSTATE_RUNNING;
tskunlock(tskcur);
// infinite loop for chat
// NOTE: this loop still needs work ...
for (;;) {
bzero(buff, MAX);
// read the message from client and copy it in buffer
int rlen = read(tskcur->tsk_sockfd, buff, sizeof(buff));
// print buffer which contains the client contents
printf("From client: %s\t To client : ", buff);
bzero(buff, MAX);
// copy server message in the buffer
// NOTE/BUG: this is destroying the data that was
#if ORIG
n = 0;
while ((buff[n++] = getchar()) != '\n');
#endif
// and send that buffer to client
write(tskcur->tsk_sockfd, buff, rlen);
// if msg contains "Exit" then server exit and chat ended.
if (strncmp("exit", buff, 4) == 0) {
printf("Server Exit...\n");
break;
}
// echo message to all other clients
tsksendall(buff,rlen);
}
tsklock(tskcur);
tskcur->tsk_state = TSKSTATE_DONE;
close(tskcur->tsk_sockfd);
tskcur->tsk_sockfd = -1;
tskunlock(tskcur);
return (void *) 0;
}
// Driver function
int
main(void)
{
int sockfd, connfd;
socklen_t len;
struct sockaddr_in servaddr, cli;
int state;
tsk_t *tsktry;
tsk_t *tsknew;
// socket create and verification
sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (sockfd == -1) {
printf("socket creation failed...\n");
exit(0);
}
else
printf("Socket successfully created..\n");
// assign IP, PORT
bzero(&servaddr, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = INADDR_ANY;
servaddr.sin_port = htons(PORT);
// Binding newly created socket to given IP and verification
if ((bind(sockfd, (SA *) & servaddr, sizeof(servaddr))) != 0) {
printf("socket bind failed...\n");
exit(0);
}
else
printf("Socket successfully binded..\n");
// Now server is ready to listen and verification
if ((listen(sockfd, TSKMAX)) != 0) {
printf("Listen failed...\n");
exit(0);
}
else
printf("Server listening..\n");
// Accept the data packet from client and verification
len = sizeof(cli);
for (TSKFORALL(tsktry)) {
pthread_mutex_init(&tsktry->tsk_mutex,NULL);
tsktry->tsk_state = TSKSTATE_IDLE;
}
while (1) {
connfd = accept(sockfd, (SA *) &cli, &len);
if (connfd < 0) {
printf("server acccept failed...\n");
exit(0);
}
else
printf("server acccept the client..%d.\n", connfd);
// reap all completed threads
tskreapall();
// find an idle slot
tsknew = NULL;
for (TSKFORALL(tsktry)) {
tsklock(tsktry);
state = tsktry->tsk_state;
if (state == TSKSTATE_IDLE) {
tsknew = tsktry;
tsknew->tsk_state = TSKSTATE_PENDING;
}
tskunlock(tsktry);
if (tsknew != NULL)
break;
}
tsknew->tsk_xid = ++tskxid;
tsknew->tsk_sockfd = connfd;
if (pthread_create(&tsknew->tsk_tid, NULL, func, tsknew) < 0) {
perror("could not create thread");
return 1;
}
}
// After chatting close the socket
close(sockfd);
return 0;
}