![\"image\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260121234108-69716414e13e0.png\")
<\/p>\n\u4f5c\u4e3a\u540e\u7aef\u5f00\u53d1\u7684\u6838\u5fc3\u6280\u80fd，Linux \u4e0b\u7684 TCP \u670d\u52a1\u5668\u5f00\u53d1\u662f\u7ed5\u4e0d\u5f00\u7684\u77e5\u8bc6\u70b9\u3002\u672c\u6587\u5c06\u4ece\u57fa\u7840\u7684 socket \u7f16\u7a0b\u5165\u624b，\u4e00\u6b65\u6b65\u5b9e\u73b0 echo \u670d\u52a1\u5668，\u5e76\u901a\u8fc7\u591a\u8fdb\u7a0b\u3001\u591a\u7ebf\u7a0b\u3001\u7ebf\u7a0b\u6c60\u4f18\u5316\u5e76\u53d1\u80fd\u529b，\u6700\u540e\u6269\u5c55\u5230\u8fdc\u7a0b\u547d\u4ee4\u6267\u884c\u573a\u666f\u5e76\u8865\u5145\u5b89\u5168\u9632\u62a4\u65b9\u6848，\u5168\u7a0b\u4ee5\u5b9e\u6218\u4ee3\u7801\u548c\u6838\u5fc3\u95ee\u9898\u4e3a\u6838\u5fc3\u5c55\u5f00\u3002<\/p>\n
echo \u670d\u52a1\u5668\u7684\u6838\u5fc3\u903b\u8f91\u5f88\u7b80\u5355 \u2014\u2014 \u5ba2\u6237\u7aef\u53d1\u4ec0\u4e48，\u670d\u52a1\u5668\u5c31\u8fd4\u56de\u4ec0\u4e48\u3002\u8fd9\u4e00\u6b65\u6211\u4eec\u5148\u641e\u5b9a\u57fa\u7840\u7684 socket \u7f16\u7a0b\u6d41\u7a0b，\u4ee5\u53ca\u5f00\u53d1\u4e2d\u6700\u5bb9\u6613\u8e29\u7684\u7ed1\u5b9a\u3001\u8fde\u63a5\u95ee\u9898\u3002<\/p>\n
\u5728\u7f16\u5199\u670d\u52a1\u5668\u4ee3\u7801\u524d，\u5148\u7406\u6e05\u4e24\u4e2a\u9ad8\u9891\u95ee\u9898：bind\u7ed1\u5b9a\u548cconnect\u8fde\u63a5\u53c2\u6570\u3002<\/p>\n
<\/p>\n
\u670d\u52a1\u5668\u7aef\u8c03\u7528bind\u51fd\u6570\u65f6，\u6838\u5fc3\u662f\u7ed1\u5b9a IP \u548c\u7aef\u53e3：<\/p>\n
![\"image\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260121234109-697164156f0f2.png\")
<\/p>\n
\u5ba2\u6237\u7aef\u7684connect\u51fd\u6570\u6838\u5fc3\u662f\u6307\u5b9a\u8981\u8fde\u63a5\u7684\u670d\u52a1\u5668\u4fe1\u606f：<\/p>\n
![\"image\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260121234109-69716415aa30d.png\")
<\/p>\n
\u7ed9\u5927\u5bb6\u8d34\u4e00\u6bb5\u5ba2\u6237\u7aefconnect\u7684\u6838\u5fc3\u4ee3\u7801，\u4e00\u770b\u5c31\u61c2：<\/p>\n
c<\/p>\n
\u8fd0\u884c<\/p>\n
\/\/ \u521d\u59cb\u5316\u670d\u52a1\u5668\u5730\u5740\u7ed3\u6784
\nstruct sockaddr_in server_addr;
\nmemset(&server_addr, 0, sizeof(server_addr));
\nserver_addr.sin_family = AF_INET;
\nserver_addr.sin_port = htons(8080); \/\/ \u670d\u52a1\u5668\u7aef\u53e3
\ninet_pton(AF_INET, "127.0.0.1", &server_addr.sin_addr); \/\/ \u670d\u52a1\u5668IP<\/p>\n
\/\/ \u8fde\u63a5\u670d\u52a1\u5668
\nint ret = connect(client_sock, (struct sockaddr*)&server_addr, sizeof(server_addr));
\nif (ret == -1) {
\n perror("connect failed");
\n close(client_sock);
\n return -1;
\n}<\/p>\n
\u7406\u6e05\u6838\u5fc3\u95ee\u9898\u540e，\u76f4\u63a5\u4e0a echo \u5ba2\u6237\u7aef\u548c\u670d\u52a1\u5668\u7684\u6838\u5fc3\u4ee3\u7801，\u7ed3\u5408\u56fe\u7247\u91cc\u7684\u903b\u8f91\u62c6\u89e3\u3002<\/p>\n
![\"image\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260121234110-69716416106b2.png\")
<\/p>\n
echo \u5ba2\u6237\u7aef\u6838\u5fc3\u6d41\u7a0b：\u521b\u5efa socket \u2192 \u8fde\u63a5\u670d\u52a1\u5668 \u2192 \u53d1\u9001\u6570\u636e \u2192 \u63a5\u6536\u8fd4\u56de\u6570\u636e \u2192 \u5173\u95ed socket\u3002<\/p>\n
\u6838\u5fc3\u4ee3\u7801\u7247\u6bb5：<\/p>\n
c<\/p>\n
\u8fd0\u884c<\/p>\n
#include <stdio.h>
\n#include <stdlib.h>
\n#include <string.h>
\n#include <unistd.h>
\n#include <sys\/socket.h>
\n#include <netinet\/in.h>
\n#include <arpa\/inet.h><\/p>\n
#define SERVER_IP "127.0.0.1"
\n#define SERVER_PORT 8080
\n#define BUF_SIZE 1024<\/p>\n
int main() {
\n \/\/ 1. \u521b\u5efa\u5ba2\u6237\u7aefsocket
\n int client_sock = socket(AF_INET, SOCK_STREAM, 0);
\n if (client_sock == -1) {
\n perror("socket failed");
\n return -1;
\n }<\/p>\n
\/\/ 2. \u521d\u59cb\u5316\u670d\u52a1\u5668\u5730\u5740
\n struct sockaddr_in server_addr;
\n memset(&server_addr, 0, sizeof(server_addr));
\n server_addr.sin_family = AF_INET;
\n server_addr.sin_port = htons(SERVER_PORT);
\n inet_pton(AF_INET, SERVER_IP, &server_addr.sin_addr);<\/p>\n
\/\/ 3. \u8fde\u63a5\u670d\u52a1\u5668
\n if (connect(client_sock, (struct sockaddr*)&server_addr, sizeof(server_addr)) == -1) {
\n perror("connect failed");
\n close(client_sock);
\n return -1;
\n }<\/p>\n
\/\/ 4. \u53d1\u9001\u6570\u636e\u5e76\u63a5\u6536echo
\n char buf[BUF_SIZE] = "Hello Echo Server!";
\n write(client_sock, buf, strlen(buf)); \/\/ \u53d1\u9001\u6570\u636e
\n memset(buf, 0, BUF_SIZE);
\n read(client_sock, buf, BUF_SIZE); \/\/ \u63a5\u6536\u8fd4\u56de\u6570\u636e
\n printf("Received from server: %s\\\\n", buf);<\/p>\n
\/\/ 5. \u5173\u95edsocket
\n close(client_sock);
\n return 0;
\n}<\/p>\n
![\"image\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260121234110-697164166e0dc.png\")
<\/p>\n
echo \u670d\u52a1\u5668\u6838\u5fc3\u6d41\u7a0b：\u521b\u5efa socket \u2192 \u7ed1\u5b9a IP \u7aef\u53e3 \u2192 \u76d1\u542c \u2192 \u63a5\u53d7\u8fde\u63a5 \u2192 \u8bfb\u53d6\u6570\u636e \u2192 \u539f\u6837\u8fd4\u56de \u2192 \u5173\u95ed\u8fde\u63a5\u3002<\/p>\n
\u6838\u5fc3\u4ee3\u7801\u7247\u6bb5：<\/p>\n
c<\/p>\n
\u8fd0\u884c<\/p>\n
#include <stdio.h>
\n#include <stdlib.h>
\n#include <string.h>
\n#include <unistd.h>
\n#include <sys\/socket.h>
\n#include <netinet\/in.h>
\n#include <arpa\/inet.h><\/p>\n
#define SERVER_PORT 8080
\n#define BUF_SIZE 1024<\/p>\n
int main() {
\n \/\/ 1. \u521b\u5efa\u76d1\u542csocket
\n int listen_sock = socket(AF_INET, SOCK_STREAM, 0);
\n if (listen_sock == -1) {
\n perror("socket failed");
\n return -1;
\n }<\/p>\n
\/\/ 2. \u521d\u59cb\u5316\u670d\u52a1\u5668\u5730\u5740（\u7ed1\u5b9a0.0.0.0:8080）
\n struct sockaddr_in server_addr;
\n memset(&server_addr, 0, sizeof(server_addr));
\n server_addr.sin_family = AF_INET;
\n server_addr.sin_port = htons(SERVER_PORT);
\n server_addr.sin_addr.s_addr = INADDR_ANY; \/\/ \u7b49\u4ef7\u4e8e0.0.0.0<\/p>\n
\/\/ 3. \u7ed1\u5b9a\u5730\u5740
\n if (bind(listen_sock, (struct sockaddr*)&server_addr, sizeof(server_addr)) == -1) {
\n perror("bind failed");
\n close(listen_sock);
\n return -1;
\n }<\/p>\n
\/\/ 4. \u76d1\u542c（backlog\u8bbe\u4e3a5，\u5141\u8bb85\u4e2a\u534a\u8fde\u63a5）
\n if (listen(listen_sock, 5) == -1) {
\n perror("listen failed");
\n close(listen_sock);
\n return -1;
\n }
\n printf("Echo server listening on 0.0.0.0:%d\\\\n", SERVER_PORT);<\/p>\n
\/\/ 5. \u63a5\u53d7\u8fde\u63a5\u5e76\u5904\u7406echo
\n struct sockaddr_in client_addr;
\n socklen_t client_addr_len = sizeof(client_addr);
\n int conn_sock = accept(listen_sock, (struct sockaddr*)&client_addr, &client_addr_len);
\n if (conn_sock == -1) {
\n perror("accept failed");
\n close(listen_sock);
\n return -1;
\n }
\n printf("Client connected: %s:%d\\\\n", inet_ntoa(client_addr.sin_addr), ntohs(client_addr.sin_port));<\/p>\n
\/\/ 6. \u8bfb\u53d6\u5ba2\u6237\u7aef\u6570\u636e\u5e76\u539f\u6837\u8fd4\u56de
\n char buf[BUF_SIZE];
\n ssize_t n = read(conn_sock, buf, BUF_SIZE);
\n if (n > 0) {
\n write(conn_sock, buf, n); \/\/ \u539f\u6837\u8fd4\u56de
\n }<\/p>\n
\/\/ 7. \u5173\u95ed\u8fde\u63a5
\n close(conn_sock);
\n close(listen_sock);
\n return 0;
\n}<\/p>\n
\u4e0a\u9762\u7684\u57fa\u7840\u7248\u670d\u52a1\u5668\u6709\u4e2a\u81f4\u547d\u95ee\u9898 \u2014\u2014 \u53ea\u80fd\u5904\u7406\u4e00\u4e2a\u5ba2\u6237\u7aef\u8fde\u63a5，\u5904\u7406\u5b8c\u5c31\u9000\u51fa\u4e86\u3002\u8981\u652f\u6301\u5e76\u53d1，\u9996\u5148\u60f3\u5230\u7528\u591a\u8fdb\u7a0b：\u7236\u8fdb\u7a0b\u8d1f\u8d23\u63a5\u53d7\u8fde\u63a5，\u5b50\u8fdb\u7a0b\u8d1f\u8d23\u5904\u7406\u4e1a\u52a1\u3002<\/p>\n
![\"image\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260121234110-69716416a845c.png\")
<\/p>\n
\u6838\u5fc3\u8bbe\u8ba1\u601d\u8def：<\/p>\n
\u4f18\u5316\u540e\u7684\u591a\u8fdb\u7a0b\u670d\u52a1\u5668\u6838\u5fc3\u4ee3\u7801（\u53ea\u6539 accept \u540e\u7684\u903b\u8f91）：<\/p>\n
c<\/p>\n
\u8fd0\u884c<\/p>\n
\/\/ \u66ff\u6362\u57fa\u7840\u7248\u4e2daccept\u540e\u7684\u4ee3\u7801
\nwhile (1) { \/\/ \u7236\u8fdb\u7a0b\u5faa\u73af\u63a5\u53d7\u8fde\u63a5
\n struct sockaddr_in client_addr;
\n socklen_t client_addr_len = sizeof(client_addr);
\n int conn_sock = accept(listen_sock, (struct sockaddr*)&client_addr, &client_addr_len);
\n if (conn_sock == -1) {
\n perror("accept failed");
\n continue;
\n }
\n printf("Client connected: %s:%d\\\\n", inet_ntoa(client_addr.sin_addr), ntohs(client_addr.sin_port));<\/p>\n
\/\/ \u521b\u5efa\u5b50\u8fdb\u7a0b\u5904\u7406\u4e1a\u52a1
\n pid_t pid = fork();
\n if (pid == -1) {
\n perror("fork failed");
\n close(conn_sock);
\n continue;
\n } else if (pid == 0) { \/\/ \u5b50\u8fdb\u7a0b
\n close(listen_sock); \/\/ \u5b50\u8fdb\u7a0b\u4e0d\u9700\u8981\u76d1\u542c\u5957\u63a5\u5b57，\u5173\u95ed！
\n \/\/ \u5904\u7406echo\u4e1a\u52a1
\n char buf[BUF_SIZE];
\n ssize_t n = read(conn_sock, buf, BUF_SIZE);
\n if (n > 0) {
\n write(conn_sock, buf, n);
\n }
\n close(conn_sock); \/\/ \u5b50\u8fdb\u7a0b\u5904\u7406\u5b8c\u5173\u95ed\u8fde\u63a5
\n exit(0); \/\/ \u5b50\u8fdb\u7a0b\u9000\u51fa
\n } else { \/\/ \u7236\u8fdb\u7a0b
\n close(conn_sock); \/\/ \u7236\u8fdb\u7a0b\u4e0d\u9700\u8981\u8fde\u63a5\u5957\u63a5\u5b57，\u5173\u95ed！
\n }
\n}<\/p>\n
\u591a\u8fdb\u7a0b\u6a21\u578b\u6709\u4e2a\u5751：\u5b50\u8fdb\u7a0b\u9000\u51fa\u540e，\u5982\u679c\u7236\u8fdb\u7a0b\u4e0d\u56de\u6536，\u4f1a\u53d8\u6210\u50f5\u5c38\u8fdb\u7a0b，\u5360\u7528\u7cfb\u7edf\u8d44\u6e90\u3002<\/p>\n
![\"image\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260121234111-6971641734806.png\")
<\/p>\n
\u5b50\u8fdb\u7a0b\u9000\u51fa\u65f6\u4f1a\u7ed9\u7236\u8fdb\u7a0b\u53d1SIGCHLD\u4fe1\u53f7，\u6211\u4eec\u53ef\u4ee5\u6ce8\u518c\u4fe1\u53f7\u5904\u7406\u51fd\u6570，\u7528waitpid\u975e\u963b\u585e\u56de\u6536\u5b50\u8fdb\u7a0b：<\/p>\n
c<\/p>\n
\u8fd0\u884c<\/p>\n
#include <signal.h>
\n#include <sys\/wait.h><\/p>\n
\/\/ \u4fe1\u53f7\u5904\u7406\u51fd\u6570：\u56de\u6536\u50f5\u5c38\u8fdb\u7a0b
\nvoid handle_sigchld(int sig) {
\n \/\/ WNOHANG：\u975e\u963b\u585e，\u6709\u5b50\u8fdb\u7a0b\u9000\u51fa\u5c31\u56de\u6536，\u6ca1\u6709\u5c31\u8fd4\u56de
\n while (waitpid(-1, NULL, WNOHANG) > 0);
\n}<\/p>\n
\/\/ \u5728main\u51fd\u6570\u7684socket\u521b\u5efa\u540e，\u6ce8\u518c\u4fe1\u53f7
\nsignal(SIGCHLD, handle_sigchld);<\/p>\n
![\"image\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260121234111-6971641753b6b.png\")
<\/p>\n
\u6838\u5fc3\u903b\u8f91：<\/p>\n
![\"image\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260121234111-697164177c4cc.png\")
<\/p>\n
\u4ee3\u7801\u5b9e\u73b0（\u4fee\u6539 fork \u90e8\u5206）：<\/p>\n
c<\/p>\n
\u8fd0\u884c<\/p>\n
pid_t pid = fork();
\nif (pid == -1) {
\n perror("fork failed");
\n close(conn_sock);
\n continue;
\n} else if (pid == 0) { \/\/ \u5b50\u8fdb\u7a0b
\n pid_t grand_pid = fork();
\n if (grand_pid == -1) {
\n exit(1);
\n } else if (grand_pid == 0) { \/\/ \u5b59\u5b50\u8fdb\u7a0b
\n close(listen_sock);
\n \/\/ \u5904\u7406echo\u4e1a\u52a1
\n char buf[BUF_SIZE];
\n ssize_t n = read(conn_sock, buf, BUF_SIZE);
\n if (n > 0) write(conn_sock, buf, n);
\n close(conn_sock);
\n exit(0);
\n } else { \/\/ \u5b50\u8fdb\u7a0b
\n exit(0); \/\/ \u5b50\u8fdb\u7a0b\u7acb\u5373\u9000\u51fa，\u5b59\u5b50\u8fdb\u7a0b\u53d8\u6210\u5b64\u513f
\n }
\n} else { \/\/ \u7236\u8fdb\u7a0b
\n close(conn_sock);
\n \/\/ \u7236\u8fdb\u7a0b\u4e0d\u9700\u8981\u5904\u7406\u5b50\u8fdb\u7a0b\u9000\u51fa，\u56e0\u4e3a\u5b50\u8fdb\u7a0b\u5df2\u7ecf\u9000\u51fa\u4e86
\n}<\/p>\n
![\"image\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260121234111-69716417d0dab.png\")
<\/p>\n
\u901a\u8fc7accept\u7684\u7b2c\u4e8c\u4e2a\u53c2\u6570client_addr，\u53ef\u4ee5\u8f7b\u677e\u83b7\u53d6\u5ba2\u6237\u7aef\u7684 IP \u548c\u7aef\u53e3：<\/p>\n
c<\/p>\n
\u8fd0\u884c<\/p>\n
\/\/ accept\u540e\u7684\u4ee3\u7801
\nchar client_ip[INET_ADDRSTRLEN];
\ninet_ntop(AF_INET, &client_addr.sin_addr, client_ip, INET_ADDRSTRLEN);
\nuint16_t client_port = ntohs(client_addr.sin_port);
\nprintf("Client connected: %s:%d\\\\n", client_ip, client_port);<\/p>\n
![\"image\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260121234111-69716417f2ff2.png\")
<\/p>\n
\u591a\u8fdb\u7a0b\u867d\u7136\u89e3\u51b3\u4e86\u5e76\u53d1\u95ee\u9898，\u4f46\u7f3a\u70b9\u5f88\u660e\u663e：<\/p>\n
\u7ebf\u7a0b\u662f\u8f7b\u91cf\u7ea7\u8fdb\u7a0b，\u521b\u5efa \/ \u9500\u6bc1\u5f00\u9500\u8fdc\u5c0f\u4e8e\u8fdb\u7a0b，\u4e14\u7ebf\u7a0b\u95f4\u5171\u4eab\u8fdb\u7a0b\u8d44\u6e90（\u5982\u6587\u4ef6\u63cf\u8ff0\u7b26\u3001\u5185\u5b58），\u9002\u5408\u9ad8\u5e76\u53d1\u573a\u666f\u3002<\/p>\n
![\"image\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260121234112-6971641832022.png\")
<\/p>\n
\u6838\u5fc3\u601d\u8def：<\/p>\n
\u6838\u5fc3\u4ee3\u7801（\u66ff\u6362\u591a\u8fdb\u7a0b\u7684 fork \u903b\u8f91）：<\/p>\n
c<\/p>\n
\u8fd0\u884c<\/p>\n
#include <pthread.h><\/p>\n
\/\/ \u7ebf\u7a0b\u5904\u7406\u51fd\u6570（\u6ce8\u610f\u53c2\u6570\u5fc5\u987b\u662fvoid*\u7c7b\u578b）
\nvoid* echo_handler(void* arg) {
\n int conn_sock = *(int*)arg;
\n free(arg); \/\/ \u91ca\u653e\u4f20\u53c2\u7684\u5185\u5b58<\/p>\n
\/\/ \u5206\u79bb\u7ebf\u7a0b：\u7ebf\u7a0b\u9000\u51fa\u540e\u81ea\u52a8\u91ca\u653e\u8d44\u6e90，\u4e0d\u9700\u8981pthread_join
\n pthread_detach(pthread_self());<\/p>\n
\/\/ \u5904\u7406echo\u4e1a\u52a1
\n char buf[BUF_SIZE];
\n ssize_t n = read(conn_sock, buf, BUF_SIZE);
\n if (n > 0) {
\n write(conn_sock, buf, n);
\n }<\/p>\n
close(conn_sock);
\n return NULL;
\n}<\/p>\n
\/\/ accept\u540e\u7684\u903b\u8f91
\nwhile (1) {
\n struct sockaddr_in client_addr;
\n socklen_t client_addr_len = sizeof(client_addr);
\n int conn_sock = accept(listen_sock, (struct sockaddr*)&client_addr, &client_addr_len);
\n if (conn_sock == -1) {
\n perror("accept failed");
\n continue;
\n }<\/p>\n
\/\/ \u4e3a\u7ebf\u7a0b\u4f20\u53c2（\u4e0d\u80fd\u76f4\u63a5\u4f20\u6808\u53d8\u91cf，\u8981\u7528\u5806）
\n int* p_conn_sock = malloc(sizeof(int));
\n *p_conn_sock = conn_sock;<\/p>\n
\/\/ \u521b\u5efa\u7ebf\u7a0b
\n pthread_t tid;
\n if (pthread_create(&tid, NULL, echo_handler, p_conn_sock) != 0) {
\n perror("pthread_create failed");
\n free(p_conn_sock);
\n close(conn_sock);
\n }
\n}<\/p>\n
![\"image\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260121234112-697164185eec1.png\")
<\/p>\n
\u6587\u4ef6\u63cf\u8ff0\u7b26（FD）\u662f\u8fdb\u7a0b\u7ea7\u8d44\u6e90，\u6240\u6709\u7ebf\u7a0b\u5171\u4eab\u540c\u4e00\u4e2a\u8fdb\u7a0b\u7684 FD \u8868\u3002\u6bd4\u5982\u4e3b\u7ebf\u7a0b\u6253\u5f00\u7684listen_sock，\u6240\u6709\u5b50\u7ebf\u7a0b\u90fd\u80fd\u770b\u5230；\u5b50\u7ebf\u7a0b\u521b\u5efa\u7684conn_sock，\u4e3b\u7ebf\u7a0b\u4e5f\u80fd\u64cd\u4f5c\u3002<\/p>\n
\u591a\u7ebf\u7a0b\u6a21\u578b\u9002\u914d\u4e0d\u540c\u7684\u4e1a\u52a1\u573a\u666f：<\/p>\n
\u591a\u7ebf\u7a0b\u867d\u7136\u6bd4\u591a\u8fdb\u7a0b\u9ad8\u6548，\u4f46\u5982\u679c\u8fde\u63a5\u6570\u66b4\u589e（\u6bd4\u5982\u4e0a\u4e07），\u9891\u7e41\u521b\u5efa \/ \u9500\u6bc1\u7ebf\u7a0b\u7684\u5f00\u9500\u4f9d\u7136\u5f88\u5927\u3002\u7ebf\u7a0b\u6c60\u5c31\u662f\u63d0\u524d\u521b\u5efa\u4e00\u6279\u7ebf\u7a0b，\u653e\u5728\u6c60\u5b50\u91cc，\u6709\u8fde\u63a5\u5c31\u5206\u914d\u7ebf\u7a0b\u5904\u7406，\u5904\u7406\u5b8c\u7ebf\u7a0b\u56de\u5230\u6c60\u5b50，\u907f\u514d\u9891\u7e41\u521b\u5efa\u9500\u6bc1\u3002<\/p>\n
![\"image\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260121234112-69716418c4ac0.png\")
<\/p>\n
\u7ebf\u7a0b\u6c60\u7684\u6838\u5fc3\u662f \u201c\u4efb\u52a1\u961f\u5217 + \u4e92\u65a5\u9501 + \u6761\u4ef6\u53d8\u91cf\u201d：<\/p>\n
![\"image\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260121234112-69716418ef152.png\")
<\/p>\n
c<\/p>\n
\u8fd0\u884c<\/p>\n
#include <stdio.h>
\n#include <stdlib.h>
\n#include <string.h>
\n#include <unistd.h>
\n#include <pthread.h>
\n#include <sys\/socket.h>
\n#include <netinet\/in.h><\/p>\n
#define THREAD_POOL_SIZE 4 \/\/ \u7ebf\u7a0b\u6c60\u5927\u5c0f
\n#define BUF_SIZE 1024
\n#define SERVER_PORT 8080<\/p>\n
\/\/ \u4efb\u52a1\u7ed3\u6784\u4f53：\u5b58\u653e\u8fde\u63a5\u5957\u63a5\u5b57
\ntypedef struct {
\n int conn_sock;
\n} Task;<\/p>\n
\/\/ \u4efb\u52a1\u961f\u5217
\nTask task_queue[1024];
\nint queue_head = 0;
\nint queue_tail = 0;<\/p>\n
\/\/ \u540c\u6b65\u673a\u5236
\npthread_mutex_t queue_mutex = PTHREAD_MUTEX_INITIALIZER;
\npthread_cond_t queue_cond = PTHREAD_COND_INITIALIZER;<\/p>\n
\/\/ \u7ebf\u7a0b\u5904\u7406\u51fd\u6570
\nvoid* thread_worker(void* arg) {
\n while (1) {
\n \/\/ \u52a0\u9501
\n pthread_mutex_lock(&queue_mutex);<\/p>\n
\/\/ \u4efb\u52a1\u961f\u5217\u4e3a\u7a7a，\u963b\u585e\u7b49\u5f85
\n while (queue_head == queue_tail) {
\n pthread_cond_wait(&queue_cond, &queue_mutex);
\n }<\/p>\n
\/\/ \u53d6\u51fa\u4efb\u52a1
\n Task task = task_queue[queue_head];
\n queue_head = (queue_head + 1) % 1024;<\/p>\n
\/\/ \u89e3\u9501
\n pthread_mutex_unlock(&queue_mutex);<\/p>\n
\/\/ \u5904\u7406echo\u4e1a\u52a1
\n char buf[BUF_SIZE];
\n ssize_t n = read(task.conn_sock, buf, BUF_SIZE);
\n if (n > 0) {
\n write(task.conn_sock, buf, n);
\n }
\n close(task.conn_sock);
\n }
\n return NULL;
\n}<\/p>\n
\/\/ \u521d\u59cb\u5316\u7ebf\u7a0b\u6c60
\nvoid init_thread_pool() {
\n pthread_t tid;
\n for (int i = 0; i < THREAD_POOL_SIZE; i++) {
\n pthread_create(&tid, NULL, thread_worker, NULL);
\n pthread_detach(tid);
\n }
\n}<\/p>\n
\/\/ \u6dfb\u52a0\u4efb\u52a1\u5230\u961f\u5217
\nvoid add_task(int conn_sock) {
\n pthread_mutex_lock(&queue_mutex);<\/p>\n
\/\/ \u653e\u5165\u4efb\u52a1\u961f\u5217
\n task_queue[queue_tail].conn_sock = conn_sock;
\n queue_tail = (queue_tail + 1) % 1024;<\/p>\n
\/\/ \u53d1\u9001\u4fe1\u53f7\u5524\u9192\u7ebf\u7a0b
\n pthread_cond_signal(&queue_cond);<\/p>\n
pthread_mutex_unlock(&queue_mutex);
\n}<\/p>\n
int main() {
\n \/\/ \u521d\u59cb\u5316\u7ebf\u7a0b\u6c60
\n init_thread_pool();<\/p>\n
\/\/ \u521b\u5efa\u76d1\u542csocket（\u548c\u57fa\u7840\u7248\u4e00\u6837）
\n int listen_sock = socket(AF_INET, SOCK_STREAM, 0);
\n struct sockaddr_in server_addr;
\n memset(&server_addr, 0, sizeof(server_addr));
\n server_addr.sin_family = AF_INET;
\n server_addr.sin_port = htons(SERVER_PORT);
\n server_addr.sin_addr.s_addr = INADDR_ANY;
\n bind(listen_sock, (struct sockaddr*)&server_addr, sizeof(server_addr));
\n listen(listen_sock, 5);<\/p>\n
\/\/ \u4e3b\u7ebf\u7a0b\u5faa\u73afaccept
\n while (1) {
\n struct sockaddr_in client_addr;
\n socklen_t client_addr_len = sizeof(client_addr);
\n int conn_sock = accept(listen_sock, (struct sockaddr*)&client_addr, &client_addr_len);
\n if (conn_sock == -1) continue;<\/p>\n
\/\/ \u6dfb\u52a0\u4efb\u52a1\u5230\u7ebf\u7a0b\u6c60
\n add_task(conn_sock);
\n }<\/p>\n
close(listen_sock);
\n return 0;
\n}<\/p>\n
![\"image\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260121234113-697164195bdcc.png\")
<\/p>\n
\u7ebf\u7a0b\u6c60\u7684\u4f18\u52bf\u5728\u4e8e \u201c\u89e3\u8026\u201d：<\/p>\n
\u628a echo \u7684\u903b\u8f91\u6539\u6210 \u201c\u5ba2\u6237\u7aef\u53d1\u547d\u4ee4，\u670d\u52a1\u5668\u6267\u884c\u5e76\u8fd4\u56de\u7ed3\u679c\u201d，\u662f\u5f88\u5e38\u89c1\u7684\u540e\u7aef\u9700\u6c42，\u4f46\u8fd9\u91cc\u6709\u5de8\u5927\u7684\u5b89\u5168\u98ce\u9669，\u5fc5\u987b\u505a\u9632\u62a4\u3002<\/p>\n
\u6838\u5fc3\u601d\u8def：\u5ba2\u6237\u7aef\u53d1\u9001\u547d\u4ee4\u5b57\u7b26\u4e32（\u5982ls\u3001pwd），\u670d\u52a1\u5668\u7528popen\u6267\u884c\u547d\u4ee4，\u8bfb\u53d6\u6267\u884c\u7ed3\u679c\u5e76\u8fd4\u56de\u7ed9\u5ba2\u6237\u7aef\u3002<\/p>\n
\u6838\u5fc3\u4ee3\u7801（\u66ff\u6362\u7ebf\u7a0b\u6c60\u7684 echo \u5904\u7406\u903b\u8f91）：<\/p>\n
c<\/p>\n
\u8fd0\u884c<\/p>\n
\/\/ \u66ff\u6362thread_worker\u91cc\u7684echo\u903b\u8f91
\nchar buf[BUF_SIZE];
\nssize_t n = read(task.conn_sock, buf, BUF_SIZE);
\nif (n > 0) {
\n buf[n-1] = '\\\\0'; \/\/ \u53bb\u6389\u6362\u884c\u7b26<\/p>\n
\/\/ \u6267\u884c\u547d\u4ee4\u5e76\u8bfb\u53d6\u7ed3\u679c
\n FILE* fp = popen(buf, "r");
\n if (fp == NULL) {
\n const char* err = "Command execute failed\\\\n";
\n write(task.conn_sock, err, strlen(err));
\n close(task.conn_sock);
\n continue;
\n }<\/p>\n
\/\/ \u8bfb\u53d6\u547d\u4ee4\u6267\u884c\u7ed3\u679c\u5e76\u8fd4\u56de
\n char result[BUF_SIZE];
\n while (fgets(result, BUF_SIZE, fp) != NULL) {
\n write(task.conn_sock, result, strlen(result));
\n }
\n pclose(fp);
\n}
\nclose(task.conn_sock);<\/p>\n
![\"image\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260121234113-69716419d1ed1.png\")
<\/p>\n
\u5982\u679c\u76f4\u63a5\u6267\u884c\u5ba2\u6237\u7aef\u53d1\u6765\u7684\u547d\u4ee4，\u98ce\u9669\u6781\u5927 \u2014\u2014 \u6bd4\u5982\u5ba2\u6237\u7aef\u53d1rm -rf \/，\u670d\u52a1\u5668\u76f4\u63a5\u73a9\u5b8c\u3002\u6240\u4ee5\u5fc5\u987b\u505a\u767d\u540d\u5355：\u53ea\u5141\u8bb8\u6267\u884c\u6307\u5b9a\u7684\u5b89\u5168\u547d\u4ee4\u3002<\/p>\n
![\"image\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260121234114-6971641a7d4c8.png\")
<\/p>\n
c<\/p>\n
\u8fd0\u884c<\/p>\n
\/\/ \u5b9a\u4e49\u767d\u540d\u5355\u547d\u4ee4
\nconst char* whitelist[] = {"ls", "pwd", "date", "whoami", NULL};<\/p>\n
\/\/ \u68c0\u67e5\u547d\u4ee4\u662f\u5426\u5728\u767d\u540d\u5355\u4e2d
\nint is_in_whitelist(const char* cmd) {
\n for (int i = 0; whitelist[i] != NULL; i++) {
\n if (strcmp(cmd, whitelist[i]) == 0) {
\n return 1;
\n }
\n }
\n return 0;
\n}<\/p>\n
\/\/ \u5728\u6267\u884c\u547d\u4ee4\u524d\u52a0\u68c0\u67e5
\nif (n > 0) {
\n buf[n-1] = '\\\\0';
\n \/\/ \u68c0\u67e5\u767d\u540d\u5355
\n if (!is_in_whitelist(buf)) {
\n const char* err = "Error: Command not allowed\\\\n";
\n write(task.conn_sock, err, strlen(err));
\n close(task.conn_sock);
\n continue;
\n }
\n \/\/ \u6267\u884c\u767d\u540d\u5355\u5185\u7684\u547d\u4ee4
\n FILE* fp = popen(buf, "r");
\n \/\/ … \u540e\u7eed\u903b\u8f91\u4e0d\u53d8
\n}<\/p>\n
\u672c\u6587\u4ece\u57fa\u7840\u7684 echo \u670d\u52a1\u5668\u51fa\u53d1，\u4e00\u6b65\u6b65\u4f18\u5316\u5e76\u53d1\u80fd\u529b（\u591a\u8fdb\u7a0b\u2192\u591a\u7ebf\u7a0b\u2192\u7ebf\u7a0b\u6c60），\u6700\u540e\u6269\u5c55\u5230\u8fdc\u7a0b\u547d\u4ee4\u6267\u884c\u5e76\u8865\u5145\u5b89\u5168\u9632\u62a4，\u6838\u5fc3\u77e5\u8bc6\u70b9\u603b\u7ed3：<\/p>\n
![\"image\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260121234114-6971641aca94c.png\")
<\/p>\n
![\"image\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/01\/20260121234115-6971641b553f8.png\")
<\/p>\n
\u6700\u540e\u8865\u5145\u4e24\u4e2a\u5b9e\u6218\u5c0f\u6280\u5de7：<\/p>\n
\u4f5c\u4e3a\u540e\u7aef\u5f00\u53d1\u7684\u6838\u5fc3\u6280\u80fd，Linux \u4e0b\u7684 TCP \u670d\u52a1\u5668\u5f00\u53d1\u662f\u7ed5\u4e0d\u5f00\u7684\u77e5\u8bc6\u70b9\u3002\u672c\u6587\u5c06\u4ece\u57fa\u7840\u7684 socket \u7f16\u7a0b\u5165\u624b，\u4e00\u6b65\u6b65\u5b9e\u73b0 echo \u670d\u52a1\u5668，\u5e76\u901a\u8fc7\u591a\u8fdb\u7a0b\u3001\u591a\u7ebf\u7a0b\u3001\u7ebf\u7a0b\u6c60\u4f18\u5316\u5e76\u53d1\u80fd\u529b，\u6700\u540e\u6269\u5c55\u5230\u8fdc\u7a0b\u547d\u4ee4\u6267\u884c\u573a\u666f\u5e76\u8865\u5145\u5b89\u5168\u9632\u62a4\u65b9\u6848，\u5168\u7a0b\u4ee5\u5b9e\u6218\u4ee3\u7801\u548c\u6838\u5fc3\u95ee\u9898\u4e3a\u6838\u5fc3\u5c55\u5f00\u3002
\n\u4e00\u3001\u57fa\u7840\u7bc7：\u5b9e\u73b0\u4e00\u4e2a\u80fd\u8dd1\u7684 echo \u670d\u52a1\u5668
\necho \u670d\u52a1\u5668\u7684\u6838\u5fc3\u903b\u8f91\u5f88\u7b80\u5355 \u2014\u2014 \u5ba2\u6237\u7aef\u53d1\u4ec0\u4e48，\u670d\u52a1\u5668\u5c31<\/p>\n","protected":false},"author":2,"featured_media":63632,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[58,205,43],"topic":[],"class_list":["post-63652","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-server","tag-linux","tag-tcp-ip","tag-43"],"yoast_head":"\n