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Linux【9】-----Linux系统编程(线程池和并发socket编程 c语言)

news 2025/6/29 8:13:21

目标

实现一个服务器程序，能够同时和多个客户端建立连接。
使用线程池，使用可以复用的线程，避免创建和销毁线程时的资源浪费，优化连接速度。

线程池实现

原理

线程池会提前创建出几个工作线程，

需要执行的任务，会被放入线程池的任务队列中

这几个工作线程会等待条件唤醒（pthread_cond）,一旦任务队列中存在任务，那么就会唤醒，同时执行任务队列中元素的函数指针。

另外根据工作负载的不同，线程池会动态的添加会减小线程数量以应对不同情况(为了简化，本篇文章不涉及动态添加和销毁线程)。

实现

数据结构

typedef struct ThreadPool{int max;int min;Task* TaskQueue;int queueFront;int queueRear;int queueSize;int queueCap;pthread_t* ThreadID;pthread_t manager_ThreadID;pthread_mutex_t threadpool_mutex;pthread_cond_t notFull;pthread_cond_t notEmpty;}ThreadPool;

任务队列
任务队列实际上是一个环形队列，队列的每个元素包括要执行的函数指针和传入函数的参数指针。

void queueAdd(ThreadPool* threadpool,Task* task){pthread_mutex_lock(&threadpool->threadpool_mutex);if(threadpool->queueSize == threadpool->queueCap){pthread_cond_wait(&threadpool->notFull,&threadpool->threadpool_mutex);}threadpool->TaskQueue[threadpool->queueRear].function = task->function;threadpool->TaskQueue[threadpool->queueRear].arg = task->arg;threadpool->queueRear =  (threadpool->queueRear + 1)%threadpool->queueCap;threadpool->queueSize++;pthread_mutex_unlock(&threadpool->threadpool_mutex);pthread_cond_signal(&threadpool->notEmpty);
}

工作线程

void* worker(void* arg){ThreadPool* threadpool = (ThreadPool*)arg;while(1){Task task;pthread_mutex_lock(&threadpool->threadpool_mutex);while(threadpool->queueSize == 0){pthread_cond_wait(&threadpool->notEmpty,&threadpool->threadpool_mutex);}task.function = threadpool->TaskQueue[threadpool->queueFront].function;task.arg = threadpool->TaskQueue[threadpool->queueFront].arg;threadpool->queueFront = (threadpool->queueFront + 1)%threadpool->queueCap;threadpool->queueSize--;pthread_mutex_unlock(&threadpool->threadpool_mutex);task.function(task.arg);pthread_cond_signal(&threadpool->notFull);}return NULL;
}

socket服务端实现

流程：

创建套接字
配置属性
绑定端口和ip
监听端口
等待连接
read/write

初始化

void server_init(Socket_Info* info){info->lfd=socket(AF_INET, SOCK_STREAM, 0);if(info->lfd == -1){perror("socket");exit(0);}info->sock = (struct sockaddr*)malloc(sizeof(struct sockaddr_in));info->sock->sin_family = AF_INET;info->sock->sin_port = htons(10003);   // 大端端坣info->sock->sin_addr.s_addr = INADDR_ANY;int ret = bind(info->lfd, info->sock, sizeof(struct sockaddr_in));if(ret == -1){perror("bind");exit(0);}// 3. 设置监坬ret = listen(info->lfd, LISTEN_NUM);if(ret == -1){perror("listen");exit(0);}
}

连接和处理

    while(1){SubSocketInfo* subinfo;for(int i=0; i<MAX_CONNECT; ++i){if(infos[i].cfd == -1){subinfo = &infos[i];}}int cfd = accept(socket->lfd, (struct sockaddr*)&subinfo->addr, &clilen);subinfo->cfd = cfd;if(cfd == -1){perror("accept");break;}Task task;task.arg = subinfo;task.function = server_progress;queueAdd(pool,&task);}


void* server_progress(void* arg){SubSocketInfo* infos_ptr = (SubSocketInfo*)arg;char ip[24] = {0};printf("thread id: %ld 客户端的IP地址: %s, 端口: %d\n",pthread_self(),inet_ntop(AF_INET, &infos_ptr->addr.sin_addr.s_addr, ip, sizeof(ip)),ntohs(infos_ptr->addr.sin_port));while(1){char buf[1024];memset(buf, 0, sizeof(buf));int len = read(infos_ptr->cfd, buf, sizeof(buf));if(len > 0){printf("thread id: %ld 客户端say: %s\n",pthread_self(), buf);write(infos_ptr->cfd, buf, len);}else if(len  == 0){printf("客户端断开了连接...\n");break;}else{perror("read");break;}}close(infos_ptr->cfd);infos_ptr->cfd = -1;
}