操作系统实验报告shell程序

1、文档来源为：从网络收集整理.word版本可编辑.欢迎下载支持操作系统实习报告日期:实习题目：shell程序完成人姓名：组号：学号实习内容简要 描述本实验要实现一个简单的命令解释器，也就是Linux中的shell程序。实验程序起名为ysh，要求其设计类似于目前流行的shell解释程序，如bash csh、tcsh，但不需要具备那么复杂的功能。ysh程序应当具有如下一些重要的特征：能够执行外部程序命令，命令可以带参数。能够执行fg、bg、cd、history、exit等内部命令。使用管道和输入输岀重定向。支持前后台作业，提供作业控制功能，包括打印作业的清单，改变当前运行作业的前台/后台状态，以及控

2、制作业的挂起、中止和继续运行。除此之外，在这个实验中还须做到：使用make工具建立工程。使用调试器gdb来调试程序。提供清晰、详细的设计文档和解决方案。主要代码结构（附注释）#include #include #include #include #include #include #include #include #include #include #include #include ysh.h#define NO_PIPE -1#define FD_READ 0#define FD_WRITE 1int is_founded(char * cmd)int k = 0;while(envpa

3、thk != NULL)strcpy(buf,envpathk);strcat(buf,cmd);if(access(buf,F_OK) = 0)return 1;k+;return 0;void getenviron(int n,char * s) int i = 0,j = 0,k = 0;char c;char buff80;char * p;while(c=si) != =) buffi+ = c; buffi+ = 0;if(strcmp(buff,PA TH) = 0) while(si != 0)if(si = :) buffj+ = /;buffj = 0;p = (char

4、*)malloc(strlen(buff) + 1); strcpy(p,buff);envpathk+ = p;envpathk = NULL;j = 0;i+; else buffj = si;j+;i+; elsefprintf(stderr,No match);int getline(int fd,char * buf) int i = 0;char c;while(read(fd,& c,1) bufi+ = c;if(c = n) bufi-1 = 0; return i; return i;void init_environ()int fd,n;char buf80;if(fd

5、= open(ysh_profile,O_RDONLY ,660) = -1) printf(init environ variable error!n);exit(1);while(n = getline(fd,buf) != 0) getenviron(n,buf);envhis.start = 0;envhis.end = 0;head = end = NULL;int pipel(char * input,int len) char * argv1030;char * filename0;int i,j,k,is_bg = 0;int li_cmd = 0;int fd101,pipe

6、_in = -1;int pipe_out = -1,flag = 0;pid_t pid;for(i = 0,j = 0,k = 0;i ) | (inputi = n) if(inpu ti = T) | (inpu ti = )if(inpu ti = ) flag =1;if(j 0 )bufj+ = 0;argvli_cmdk = (char *)malloc(sizeof(char) * j); strcpy(argvli_cmdk,buf);k+;argvli_cmdk = (char *)0;li_cmd+;k = 0;j = 0;if(j = 0)continue; else

7、bufj+ = 0;if(flag = 0)argvli_cmdk = (char *)malloc(sizeof(char) * j); strcpy(argvli_cmdk,buf);k+; elsefilename0 = (char *)malloc(sizeof(char) * j); strcpy(filename0,buf);j = 0;else if(inputi = &)& (inputi = 0) is_bg = 1;continue;bufj+ = inpu ti;argvli_cmdk+ = NULL;for(i = 0;i = 10;i+) fdiFD_READ = N

8、O_PIPE; fdiFD_WRITE = NO_PIPE;for(i = 0;i li_cmd;i+) if(pipe(fdi) = -1)printf(Can not open pipe!n);return 0;for(i = 0;i li_cmd;i+)if(is_founded(argvi0) = 0)printf(Can not found command!n);break;if(i != 0)pipe_in = fdi - 1FD_READ; elsepipe_in = NO_PIPE;if(i != li_cmd)pipe_out = fdiFD_WRITE;elseif(fla

9、g = 1)if(pipe_out = open(filename0,O_WRONLY | O_CREA T | O_TRUNC,S_IRUSR | S_IWUSR) = -1)printf(Can not open %sn,filename0);return 0;else pipe_out = NO_PIPE;if(pid = fork() 0)printf(Fork failed!n);return 0;if(pid = 0)if(pipe_in = NO_PIPE)close(pipe_in);if(pipe_out = NO_PIPE)close(pipe_out);if(pipe_o

10、ut != NO_PIPE)dup2(pipe_out,1);close(pipe_out);if(pipe_in != NO_PIPE) dup2(pipe_in,0);close(pipe_in);execv(buf,argvi); else if(is_bg = 0)waitpid(pid,NULL,O);close(pipe_in);close(pipe_out);return 0;void add_history(char * inputcmd)envhis.end = (envhis.end + 1) % HISNUM;if(envhis.end = envhis.start)en

11、vhis.start = (envhis.start + 1) % HISNUM; strcpy(envhis.his_cmdenvhis.end,inputcmd);void history_cmd()int i,j = 0;if(envhis.start = envhis.end)return;else if(envhis.start envhis.end)for(i = envhis.start + 1;i = envhis.end;i+)printf(%dt%sn,j,envhis.his_cmdi);j+；elsefor(i = envhis.start + 1;i HISNUM;i

12、+)printf(%dt%sn,j,envhis.his_cmdi);j+;for(i = 0;i = envhis.end;i+)printf(%dt%sn,j,envhis.his_cmdi); j+;void cd_cmd(char * route)if(route != NULL)if(chdir(route) pid,p - state,p - cmd); i+;p = p - link;while(p != NULL);elseprintf(No jobs!n);void add_node(char * input_cmd,int node_pid)struct NODE * p;

13、p = (struct NODE *)malloc(sizeof(struct NODE);p - pid = node pid;strcpy(p - state,input_cmd);strcpy(p - state,running);p - link = NULL;if(head = NULL)head = p;end = p; elseend - link = p;end = p;void del_node(int sig,siginfo_t * sip)struct NODE * q;struct NODE * p;int id;if(sig_z = 1)sig_z = 0;goto

14、out;id = sip - si_pid;p = q = head;if(head = NULL)goto out;while(p - pid != id & p - link != NULL)p = p - link;if(p - pid != id)goto out;if(p = head)head = head - link;else while(q - link != p)q = q - link;if(p = end)end = q;q - link = NULL;else q - link = p - link;free(p);out:return;void setflag()s

15、ig_flag = 1;void ctrl_z()struct NODE * p;int i = 1;if(pid1 = 0)goto out;if(head != NULL)p = head;while(p - pid != pid1) & (p - link != NULL)p = p - link;if(p - pid = pid1)strcpy(p - state,stopped);elseadd_node(input,pid1);strcpy(end - state,stopped);elseadd_node(input,pid1);strcpy(end - state,stoppe

16、d);sig_z = 1;kill(pid1,SIGSTOP);for(p = head;p - pid != pid1;p = p - link)i+;printf(%dt%st%sn,i,end - state,end - cmd);pid1 = 0;out:return;void bg_cmd(int job_num)struct NODE * p;int i = 0;p = head;for(i = 1;i link;kill(p - pid,SIGCONT); strcpy(p - state,running);void fg_cmd(int job_num)struct NODE

17、* p;int i = 0;p = head;for(i = 1;i link;strcpy(p - state,running); strcpy(input,p - cmd); pidl = p - pid;signal(SIGTSTP,ctrl_z);kill(p - pid,SIGCONT); waitpid(p - pid,NULL,O);int main()init_environ();while(1)char c;char * arg20;int i = 0,j = 0,k = 0;int is_pr = 0,is_bg = 0;int input_len = 0,path;int

18、 pid = 0,status = 0;struct sigaction action;action.sa_sigaction = del_node;sigfillset( & action.sa_mask); action.sa_flags = SA_SIGINFO; sigaction(SIGCHLD, & action,NULL); signal(SIGTSTP,ctrl_z);path = get_current_dir_name();printf(ysh%s ,path);while(c = getchar() = ) | (c = t) | (c = EOF) Jif(c = n)

19、continue;while(c != n)bufinput_len+ = c;c = getchar();bufinput_len = 0：input = (char *)malloc(sizeof(char) * (input_len + 1); strcpy(input,buf);for(i = 0,j = 0,k = 0;i = input_len;i+)if(inpu ti = ) | (inputi = |)if(inpu ti = T)pipel(input,input_len);add_history(input);free(input);elseredirect(input,

20、input_len); add_history(input);free(input);is_pr = 1;break;if(is_pr = 1)continue;for(i = 0,j = 0,k = 0;i = input_len;i+)if(inpu ti = ) | (inputi = 0)if(j = 0)continue;elsebufj+ = 0：argk = (char *)malloc(sizeof(char) * j); strcpy(argk+,buf);j = 0;elseif(inp uti = &) & (inputi + 1 = 0)is_bg = 1;contin

21、ue;bufj+ = inpu ti;if(strcmp(arg0,exit) = 0)add_history(input);printf(Bye bye!n);free(input);break;if(strcmp(arg0,history) = 0)add_history(input);history_cmd();free(input);continue;if(strcmp(arg0,cd) = 0)add_history(input);for(i = 3,j = 0;i = input_len;i+)bufj+ = inpu ti;bufj = 0;arg1 = (char *)mall

22、oc(sizeof(char) * j);strcpy(arg1,buf);cd_cmd(arg1);free(input); continue;if(strcmp(arg0,jobs) = 0)add_history(input);jobs_cmd();free(input);continue; if(strcmp(arg0,bg) = 0)add_history(input);for(i = 0;i = input_len;i+)if(inpu ti = %) break;i+;for(;i = input_len;i+)bufj+ = inpu ti;bufj = 0;arg1 = (char *)malloc(sizeof(char) * j); strcpy(arg1,buf); bg_cmd(atoi(arg1);free(input);continue; if(strcmp(arg0,fg) = 0)add_history(input);for(i = 0;i = input_len;i+) if(inpu ti = %) break;i+;for(;i = input_len;i+)bufj+ =