Linux系统编程答案.doc

Linux系统编程机试试卷答案一编程题:(共4题100分)1、 利用文件描述符的方式实现将a.txt中的内容拷贝到b.txt中 （运行：./cp a.txt b.txt）#include #include #include #include char *res = copy succeed!n;char *fail = illegal parameter!n;intmain(int argc, char *argv)if(argc != 3)write(STDOUT_FILENO, fail, strlen(fail);exit(2);intfdin, fdout;if(fdin = open(argv1, O_RDONLY) = -1)exit(2);if(fdout = open(argv2, O_WRONLY|O_CREAT, 0777) = -1)exit(2);char buff256;ssize_tnreads;while(nreads = read(fdin, buff, 256) != 0)if(write(fdout, buff, nreads) != nreads)exit(2);close(fdin);close(fdout);write(STDOUT_FILENO, res, strlen(res);return 0;2.#include #include #include #include #include #include int global = 6;char outstr = parent process begin!n;intmain(void)pid_tpid;intvalue = 88;write(STDOUT_FILENO, outstr, sizeof(outstr) - 1);printf(begin forkingn);if(pid = fork() = -1)printf(fork errorn, strerror(errno);exit(2);if(pid = 0)global+;value +;if(pid 0)sleep(2);printf(process id is %d, global is %d, value is %dn, pid, global, value);exit(0);3.#include #include #include #include void signal_handler(int);intmain(void)pid_tpid;if(signal(SIGCHLD, signal_handler) = SIG_ERR)printf(signal errorn);if(pid=fork() 0) /parentint i = 0;for(;)printf(parent: i is %dn, +i);sleep(1);else/childint i = 0;for(; i 10; i+)printf(child: i is %dn, i);sleep(2);_exit(0);exit(0);void signal_handler(int signo)if(signo = SIGCHLD)printf(child process dead!n);wait(NULL);exit(0);4.#include #include #include #include void*th_fn(void *arg)int i = 1;char *n = (char*)arg;for(i = 1; i = 100; i+)printf(%s, %dn, n, i);intmain(void)pthread_attr_tattr;pthread_attr_init(&attr);pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);pthread_ttid;int err;if(pthread_create(&tid, &attr, th_fn, detached) != 0)printf(pthread create errorn);if(err=pthread_join(tid, NULL) != 0)printf(join errorn, strerror(err);return 0;5.服务器端：#include #include #include #include #include #include #include #defineSOCKADDR structsockaddrvoidout(struct sockaddr_in *adr)char str16;printf(sockaddresst%s:%dn, inet_ntop(AF_INET, (SOCKADDR*)&adr-sin_addr.s_addr, str, 16),ntohs(adr-sin_port);intmain(void)int port = 8888;intfd;struct sockaddr_in server, client;/1 construct socket for IPV4 and TCPif(fd=socket(AF_INET, SOCK_STREAM, 0) = -1)printf(socket error: %sn, strerror(errno);exit(2);/2 construct address struct and initializationmemset(&server, 0, sizeof(server);server.sin_family = AF_INET;server.sin_port = htons(port);server.sin_addr.s_addr = INADDR_ANY;/inet_pton(AF_INET, 172.16.1.17, &server.sin_addr.s_addr);/3 bind socket to addressif(bind(fd, (SOCKADDR*)&server, sizeof(server) = -1)printf(bind errorn);exit(2);/4 notify the kernel accepting connection requestlisten(fd, 0);socklen_tlen = sizeof(client);while(1)/ 5 waiting for the client connectionint sockfd = accept(fd, (SOCKADDR*)&client, &len);out(&client);time_t t = time(NULL);char *p = ctime(&t);/ 6 send the datawrite(sockfd, p, strlen(p);/ 7 close the socketclose(sockfd);close(fd);客户端：#include #include #include #include #include #include #include intmain(int argc, char *argv)int fd;struct sockaddr_inserver;/1construct the socket for ipv4 and tcpif(fd=socket(AF_INET, SOCK_STREAM, 0) = -1)printf(socket error:%sn, strerror(errno);exit(2);/2 construct server addressmemset(&server, 0, sizeof(server);server.sin_family = AF_INET;server.sin_port = htons(atoi(argv2);inet_pton(AF_INET, argv1, (struct sockaddr *)&server.sin_addr.s_addr);/3 connect to the serverif(connect(fd, (struct sockaddr*)&server, sizeof(server) = -1)printf(can not connect to server: