\u5e76\u53d1\u670d\u52a1\u5668\u53ef\u4ee5\u540c\u65f6\u5904\u7406\u591a\u4e2a\u5ba2\u6237\u7aef\u7684\u8bf7\u6c42\uff0c\u670d\u52a1\u5668\u5bf9\u5ba2\u6237\u7aef\u7f51\u7edc\u8bf7\u6c42\u7684\u5904\u7406\u662f\u901a\u8fc7fork\u5b50\u670d\u52a1\u8fdb\u7a0b\u6765\u5b8c\u6210\u7684\u3002\u5f53\u6709\u591a\u4e2a\u5ba2\u6237\u8bf7\u6c42\u65f6\uff0c\u4e3b\u670d\u52a1\u5668\u8fdb\u7a0b\u5c31\u4f1a\u4ea7\u751f\u591a\u4e2a\u5b50\u670d\u52a1\u5668\u8fdb\u7a0b\u3002\u5f53\u8fd9\u4e9b\u5b50\u670d\u52a1\u5668\u8fdb\u7a0b\u5904\u7406\u5b8c\u5ba2\u6237\u8bf7\u6c42\u65f6\uff0c\u5c31\u7ec8\u6b62\u8fd0\u884c\u4e86\u3002\u7531\u4e8e\u4e3b\u670d\u52a1\u5668\u8fdb\u7a0b\uff08\u4e5f\u5c31\u662f\u8fd9\u4e9b\u5b50\u670d\u52a1\u5668\u8fdb\u7a0b\u7684\u7236\u4eb2\uff09\u4ecd\u7136\u5728\u8fd0\u884c\uff0c\u56e0\u6b64\u8fd9\u4e9b\u7ec8\u6b62\u7684\u5b50\u670d\u52a1\u5668\u8fdb\u7a0b\u5728\u4e3b\u670d\u52a1\u5668\u9000\u51fa\u4e4b\u524d\u5c31\u6210\u4e3a\u4e86\u50f5\u6b7b\u8fdb\u7a0b\u3002\u901a\u5e38\u670d\u52a1\u5668\u8fdb\u7a0b\u90fd\u957f\u65f6\u95f4\u5904\u4e8e\u8fd0\u884c\u72b6\u6001\uff0c\u6240\u4ee5\u8fd9\u4e9b\u50f5\u6b7b\u8fdb\u7a0b\u5c31\u4f1a\u4e00\u76f4\u5b58\u5728\u4e8e\u7cfb\u7edf\u5185\u3002\u5982\u679c\u4e0d\u53ca\u65f6\u6e05\u9664\u8fd9\u4e9b\u50f5\u6b7b\u8fdb\u7a0b\uff0c\u4ed6\u4eec\u5c06\u5360\u7528\u5185\u6838\u7684\u7a7a\u95f4\uff0c\u6700\u7ec8\u53ef\u80fd\u4f1a\u8017\u5c3d\u7cfb\u7edf\u8d44\u6e90\u3002\u672c\u6587\u5c06\u63cf\u8ff0\u5982\u4f55\u6e05\u7406\u8fd9\u4e9b\u50f5\u6b7b\u8fdb\u7a0b\u3002<\/p>\n
\u4e0b\u9762\u5c06\u901a\u8fc7\u4e00\u4e2a\u7b80\u5355\u7684C\/S\u6a21\u578b\u56de\u5c04\u7a0b\u5e8f\u6765\u6f14\u793a\u50f5\u6b7b\u8fdb\u7a0b\u7684\u4ea7\u751f\u3002\u6211\u4eec\u9996\u5148\u5c06\u670d\u52a1\u5668\u7f6e\u4e8e\u540e\u53f0\u8fd0\u884c\uff0c\u7136\u540e\u518d\u67e5\u770b\u5f53\u524d\u7ec8\u7aef\uff08pts\/3\uff09\u4e0b\u7684\u8fdb\u7a0b\u72b6\u6001\uff1a<\/p>\n
edsionte@edsionte-desktop:~\/echoCS$ ps -o pid,ppid,args,stat,wchan\r\n PID PPID COMMAND STAT WCHAN\r\n 5071 2305 bash Ss wait\r\n 6146 5071 .\/server S inet_csk_wait_for_connect\r\n 6149 5071 ps -o pid,ppid,args,stat,wc R+ -<\/pre>\n\u7531\u4e0a\u53ef\u4ee5\u770b\u51fa\uff0c\u670d\u52a1\u5668\u8fdb\u7a0b\u5904\u4e8e\u7b49\u5f85\u8fde\u63a5\u7684\u72b6\u6001\uff0c\u6b64\u523b\u5b83\u6b63\u5728\u76d1\u542c\u5ba2\u6237\u8bf7\u6c42\u3002\u63a5\u7740\u8fd0\u884c\u5ba2\u6237\u7aef\u7a0b\u5e8f\uff0c\u8fde\u63a5\u6210\u529f\u540e\u8f93\u5165\u4efb\u610f\u7684\u5b57\u7b26\u4e32\uff0c\u53ef\u4ee5\u770b\u5230\u670d\u52a1\u5668\u548c\u5ba2\u6237\u7aef\u901a\u4fe1\u6b63\u5e38\u3002<\/p>\n
edsionte@edsionte-desktop:~\/echoCS$ .\/client 127.0.0.1\r\nreceived a connection from:127.0.0.1\r\nps\r\nps<\/pre>\n\u6211\u4eec\u5728\u53e6\u4e00\u4e2a\u7ec8\u7aef\u4e0b\uff0c\u67e5\u770b\u4f4d\u4e8e\u7ec8\u7aefpts\/3\u4e0b\u5ba2\u6237\u7aef\u548c\u670d\u52a1\u5668\u8fdb\u7a0b\u7684\u72b6\u6001\u3002<\/p>\n
edsionte@edsionte-desktop:~\/echoCS$ ps -t pts\/3 -o pid,ppid,args,stat,wchan\r\n PID PPID COMMAND STAT WCHAN\r\n 5071 2305 bash Ss wait\r\n 6146 5071 .\/server S inet_csk_wait_for_connect\r\n 6150 5071 .\/client 127.0.0.1 S+ n_tty_read\r\n 6151 6146 .\/server S sk_wait_data<\/pre>\n\u7531\u4e8e\u5ba2\u6237\u8fdb\u7a0b\u53d1\u6765\u8fde\u63a5\u8bf7\u6c42\uff0c\u56e0\u6b64\u670d\u52a1\u5668\u8fdb\u7a0bfork\u4e86\u4e00\u4e2a\u5b50\u670d\u52a1\u5668\u8fdb\u7a0b\uff0c\u4ecepid\u548cppid\u53ef\u4ee5\u770b\u5230\u4e24\u4e2a\u670d\u52a1\u5668\u8fdb\u7a0b\u4e4b\u95f4\u7684\u7236\u5b50\u5173\u7cfb\u3002\u7236\u5b50\u8fdb\u7a0b\u6b64\u523b\u90fd\u5904\u4e8e\u7b49\u5f85\u72b6\u6001\uff0c\u4e0d\u8fc7\u4ed6\u4eec\u7b49\u5f85\u7684\u76ee\u6807\u4e0d\u540c\uff1a\u7236\u8fdb\u7a0b\u76d1\u542c\u5ba2\u6237\u8bf7\u6c42\uff0c\u5b50\u8fdb\u7a0b\u5219\u963b\u585e\u4e8eread\u51fd\u6570\u7b49\u5f85\u5957\u63a5\u5b57\u6570\u636e\u7684\u6765\u4e34\u3002<\/p>\n
\u63a5\u4e0b\u6765\u901a\u8fc7\u53d1\u4fe1\u53f7SIGINT\uff08\u901a\u8fc7\u952e\u76d8\u4e0a\u7684ctrl+c\u53ef\u53d1\u51fa\u6b64\u4fe1\u53f7\uff09\u4f7f\u5ba2\u6237\u8fdb\u7a0b\u7ec8\u6b62\u3002<\/p>\n
edsionte@edsionte-desktop:~\/echoCS$ .\/client 127.0.0.1\r\nreceived a connection from:127.0.0.1\r\nps\r\nps\r\n^C<\/pre>\n\u6211\u4eec\u5728\u53e6\u4e00\u4e2a\u7ec8\u7aef\u67e5\u770bpty\/3\u7ec8\u7aef\u5f53\u524d\u8fdb\u7a0b\u7684\u72b6\u6001\uff1a<\/p>\n
edsionte@edsionte-desktop:~\/echoCS$ ps -t pts\/3 -o pid,ppid,args,stat,wchan\r\n PID PPID COMMAND STAT WCHAN\r\n 5071 2305 bash Ss+ n_tty_read\r\n 6146 5071 .\/server S inet_csk_wait_for_connect\r\n 6151 6146 [server] Z exit<\/pre>\n\u53ef\u4ee5\u770b\u5230\uff0c\u5b50\u670d\u52a1\u5668\u8fdb\u7a0b\u73b0\u5728\u5904\u4e8e\u50f5\u6b7b\u72b6\u6001\u3002\u76ee\u524d\u6211\u4eec\u53ea\u6709\u8fd0\u884c\u4e86\u4e00\u6b21\u5ba2\u6237\u7aef\u7a0b\u5e8f\uff0c\u5982\u679c\u4e00\u4e2a\u670d\u52a1\u5668\u7684\u7f51\u7edc\u8bf7\u6c42\u7e41\u5fd9\uff0c\u5219\u4f1a\u4ea7\u751f\u5f88\u591a\u50f5\u6b7b\u8fdb\u7a0b\u3002<\/p>\n
2.\u5904\u7406\u50f5\u6b7b\u8fdb\u7a0b<\/h3>\n
\u5f53\u5b50\u8fdb\u7a0b\u7ec8\u6b62\u65f6\u4f1a\u7ed9\u7236\u8fdb\u7a0b\u53d1\u9001SIGCHLD\u4fe1\u53f7\uff0c\u56e0\u6b64\u6211\u4eec\u53ef\u4ee5\u5229\u7528\u4fe1\u53f7\u5904\u7406\u51fd\u6570\u6355\u83b7\u8fd9\u4e2a\u4fe1\u53f7\u5e76\u5bf9\u50f5\u6b7b\u8fdb\u7a0b\u8fdb\u884c\u5904\u7406\u3002\u6211\u4eec\u77e5\u9053\u5728\u7236\u8fdb\u7a0b\u4e2d\u8c03\u7528wait\u51fd\u6570\u53ef\u4ee5\u9632\u6b62\u5148\u4e8e\u7236\u8fdb\u7a0b\u7ec8\u6b62\u7684\u5b50\u8fdb\u7a0b\u7f16\u7a0b\u50f5\u6b7b\u8fdb\u7a0b\uff0c\u56e0\u6b64\u6211\u4eec\u7684\u4fe1\u53f7\u6355\u83b7\u51fd\u6570\u5982\u4e0b\u6240\u793a\uff1a<\/p>\n
void sig_zchild(int signo)\r\n{\r\n\tpid_t pid;\r\n\tint stat;\r\n\r\n\tpid = wait(&stat);\r\n printf(\"child %d terminated\\n\", pid);\r\n\treturn;\r\n}<\/pre>\n\u5e76\u4e14\u6211\u4eec\u9700\u8981\u9002\u5f53\u7684\u4fee\u6539\u670d\u52a1\u5668\u7a0b\u5e8f\uff0c\u5728accept\u51fd\u6570\u8c03\u7528\u4e4b\u524d\u8c03\u7528signal\u51fd\u6570\uff1a<\/p>\n
\tif(listen(sockfd, BACKLOG) == -1) {\r\n\r\n\t\tprintf(\"listen error!\\n\");\r\n\t\texit(1);\r\n\t}\r\n\r\n\tif (signal(SIGCHLD, sig_zchild) == SIG_ERR) {\r\n\t\tprintf(\"signal error!\\n\");\r\n\t\texit(1);\r\n\t}\r\n\r\n\twhile (1) {\r\n\r\n\t\tsin_size = sizeof(struct sockaddr_in);\r\n\t\tif ((client_fd = accept(sockfd, (struct sockaddr *)&remote_addr,\r\n&sin_size)) == -1) {\r\n\r\n\t\t\tprintf(\"accept error!\\n\");\r\n\t\t\tcontinue;\r\n\t\t}\r\n\t\t\u2026\u2026 \u2026\u2026\r\n\t}\/\/while<\/pre>\n\u6211\u4eec\u4e0b\u9762\u8fdb\u884c\u6d4b\u8bd5\uff0c\u6211\u4eec\u9996\u5148\u5728\u7ec8\u7aef\u540e\u53f0\u8fd0\u884c\u670d\u52a1\u5668\u7a0b\u5e8f\uff0c\u7136\u540e\u540c\u65f6\u5728\u5176\u4ed6\u591a\u4e2a\u7ec8\u7aef\u5206\u522b\u8fd0\u884c\u5ba2\u6237\u7aef\u7a0b\u5e8f\u3002\u5f53\u524d\u7ec8\u7aef\u7684\u8fdb\u7a0b\u72b6\u6001\u5982\u4e0b\uff1a<\/p>\n
edsionte@edsionte-desktop:~\/echoCS$ ps\r\n PID TTY TIME CMD\r\n 6699 pts\/0 00:00:00 bash\r\n 6926 pts\/0 00:00:00 server\r\n 6947 pts\/0 00:00:00 server\r\n 6966 pts\/0 00:00:00 server\r\n 6985 pts\/0 00:00:00 server\r\n 6986 pts\/0 00:00:00 ps<\/pre>\n\u7136\u540e\u6211\u4eec\u5206\u522b\u5728\u8fd0\u884c\u5ba2\u6237\u7a0b\u5e8f\u7684\u7ec8\u7aef\u6740\u6b7b\u5ba2\u6237\u7aef\u8fdb\u7a0b\u3002\u518d\u6b21\u67e5\u770b\u5f53\u524d\u7ec8\u7aef\u4e0b\u7684\u8fdb\u7a0b\u72b6\u6001\uff0c\u53ef\u4ee5\u53d1\u73b0\u5e76\u6ca1\u6709\u50f5\u6b7b\u7684\u5b50\u670d\u52a1\u8fdb\u7a0b\u3002\u56e0\u4e3a\u6bcf\u4e2a\u5b50\u8fdb\u7a0b\u5728\u7ec8\u6b62\u65f6\u53d1\u9001SIGCHLD\u4fe1\u53f7\u90fd\u4f1a\u88ab\u7236\u8fdb\u7a0b\u4e2d\u7684\u4fe1\u53f7\u5904\u7406\u51fd\u6570\u6355\u83b7\u3002<\/p>\n
3.\u50f5\u6b7b\u8fdb\u7a0b\u5904\u7406\u7684\u52a0\u5f3a\u7248<\/h3>\n
\u4e0a\u8ff0\u7684\u5ba2\u6237\u7aef\u8fdb\u7a0b\u6bcf\u6b21\u5411\u670d\u52a1\u5668\u7aef\u53ea\u53d1\u51fa\u4e00\u4e2a\u8fde\u63a5\u8bf7\u6c42\uff0c\u5f53\u5ba2\u6237\u7aef\u7ec8\u6b62\u65f6\u5b50\u670d\u52a1\u5668\u8fdb\u7a0b\u5c06\u7ec8\u6b62\uff1b\u5982\u679c\u4e00\u4e2a\u5ba2\u6237\u7aef\u5411\u670d\u52a1\u5668\u53d1\u51fa\u591a\u4e2a\u8fde\u63a5\u8bf7\u6c42\uff0c\u5f53\u8be5\u5ba2\u6237\u7aef\u7ec8\u6b62\u65f6\u591a\u4e2a\u5b50\u670d\u52a1\u5668\u8fdb\u7a0b\u5c06\u540c\u65f6\u7ec8\u6b62\uff0c\u4e5f\u5c31\u662f\u8bf4\u7236\u670d\u52a1\u5668\u8fdb\u7a0b\u5c06\u9762\u4e34\u540c\u65f6\u5904\u7406\u591a\u4e2aSIGCHLD\u4fe1\u53f7\u7684\u60c5\u51b5\u3002<\/p>\n
\u6309\u7167\u4e0a\u8ff0\u7684\u7279\u6b8a\u5ba2\u6237\u7aef\uff0c\u6211\u4eec\u5c06\u56de\u5c04C\/S\u6a21\u578b\u4e2d\u7684\u5ba2\u6237\u7aef\u9002\u5f53\u4fee\u6539\uff0c\u4f7f\u8fd0\u884c\u4e00\u6b21\u5ba2\u6237\u7aef\u5c31\u8fde\u63a5\u670d\u52a1\u56685\u6b21\uff0c\u8fd9\u6837\u5c31\u4f1a\u4ea7\u751f\u76f8\u5e94\u76845\u4e2a\u5b50\u670d\u52a1\u5668\u8fdb\u7a0b\u3002<\/p>\n
\r\n\tint i;\r\n\tfor (i = 0; i < 5; i++) {\r\n\t\tif((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {\r\n \t\tprintf(\"socket error!\\n\");\r\n \t\texit(1);\r\n \t}\r\n\t\r\n\t\tserv_addr.sin_family = AF_INET;\r\n \tserv_addr.sin_port = htons(SERV_PORT);\r\n \tserv_addr.sin_addr = *((struct in_addr *)host->h_addr);\r\n\r\n \tif(connect(sockfd, (struct sockaddr *)&serv_addr,\r\n\t\t\t\t\tsizeof(struct sockaddr)) == -1) {\r\n\t\t\tprintf(\"connect error!\\n\");\r\n\t \texit(1);\r\n \t}\r\n\t}\r\n\r\n\tstr_cli(stdin, sockfd);\r\n<\/pre>\n\u8fd0\u884c\u670d\u52a1\u5668\u7a0b\u5e8f\u548c\u521a\u521a\u4fee\u6539\u8fc7\u7684\u5ba2\u6237\u7aef\u7a0b\u5e8f\uff0c\u6211\u4eec\u4f5c\u5982\u4e0b\u6d4b\u8bd5\uff1a<\/p>\n
edsionte@edsionte-desktop:~\/echoCS$ ps -t pts\/0 -o pid,ppid,args,stat\r\n PID PPID COMMAND STAT\r\n 2651 2649 bash Ss\r\n 2861 2651 .\/server S\r\n 2865 2651 .\/mclient 127.0.0.1 S+\r\n 2866 2861 .\/server S\r\n 2867 2861 .\/server S\r\n 2868 2861 .\/server S\r\n 2869 2861 .\/server S\r\n 2870 2861 .\/server S\r\nedsionte@edsionte-desktop:~\/echoCS$ kill 2865\r\nedsionte@edsionte-desktop:~\/echoCS$ ps -t pts\/0 -o pid,ppid,args,stat\r\n PID PPID COMMAND STAT\r\n 2651 2649 bash Ss+\r\n 2861 2651 .\/server S\r\n 2867 2861 [server] Z\r\n 2868 2861 [server] Z\r\n 2869 2861 [server] Z\r\n 2870 2861 [server] Z<\/pre>\n\u5f53\u6740\u6b7b\u5ba2\u6237\u7aef\u8fdb\u7a0b\u540e\uff0c\u53ea\u6709\u4e00\u4e2a\u5b50\u670d\u52a1\u5668\u8fdb\u7a0b\u88abSIGCHLD\u4fe1\u53f7\u5904\u7406\u51fd\u6570\u6355\u83b7\u5904\u7406\uff0c\u5176\u4ed6\u56db\u4e2a\u5b50\u670d\u52a1\u5668\u8fdb\u7a0b\u4ecd\u7136\u5904\u4e8e\u50f5\u6b7b\u72b6\u6001\u3002\u51fa\u73b0\u8fd9\u79cd\u73b0\u8c61\u7684\u539f\u56e0\u662f\uff0c\u4e3b\u670d\u52a1\u5668\u8fdb\u7a0b\u4e2d\u7684\u4fe1\u53f7\u5904\u7406\u51fd\u6570\u4f7f\u7528\u4e86wait\u51fd\u6570\uff0c\u8be5\u51fd\u6570\u4f1a\u4e00\u76f4\u963b\u585e\u5230\u51fa\u73b0\u7b2c\u4e00\u4e2a\u7ec8\u6b62\u7684\u5b50\u8fdb\u7a0b\u3002\u4e5f\u5c31\u662f\u8bf4\uff0c\u8be5\u51fd\u6570\u53ea\u7b49\u5f85\u7b2c\u4e00\u4e2a\u7ec8\u6b62\u7684\u5b50\u8fdb\u7a0b\u5e76\u8fd4\u56de\u3002<\/p>\n
\u672c\u5ba2\u6237\u7aef\u7a0b\u5e8f\u7ec8\u6b62\u540e\uff0c\u5c06\u540c\u65f6\u4ea7\u751f5\u4e2aSIGCHLD\u4fe1\u53f7\uff0c\u800cwait\u51fd\u6570\u53ea\u5904\u7406\u5176\u4e2d\u4e00\u4e2a\uff0c\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\u7684\u529e\u6cd5\u662f\u4f7f\u7528waitpid\u51fd\u6570\u3002\u8be5\u51fd\u6570\u5c06\u5468\u671f\u6027\u7684\u68c0\u67e5\u662f\u5426\u6709\u5b50\u8fdb\u7a0b\u7ec8\u6b62\uff0c\u4e5f\u5c31\u662f\u8bf4\u53ef\u4ee5\u7b49\u5f85\u6240\u6709\u7684\u7ec8\u6b62\u5b50\u8fdb\u7a0b\u3002\u4fee\u6539\u540e\u7684\u670d\u52a1\u5668\u4fe1\u53f7\u5904\u7406\u51fd\u6570\u5982\u4e0b\uff1a<\/p>\n
void sig_zchild(int signo)\r\n{\r\n\tpid_t pid;\r\n\tint stat;\r\n\r\n\twhile ((pid = waitpid(-1, &stat, WNOHANG)) > 0)\r\n\t\tprintf(\"child %d terminated\\n\", pid);\r\n\r\n\treturn;\r\n}<\/pre>\n\u6309\u6b64\u4fee\u6539\u540eSIGCHLD\u4fe1\u53f7\u5904\u7406\u51fd\u6570\u540e\uff0c\u5c31\u53ef\u4ee5\u907f\u514d\u7559\u4e0b\u50f5\u6b7b\u8fdb\u7a0b\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
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