操作系统实验报告shell程序.docx

1、操作系统实验报告shell程序操作系统实习报告 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。 使用管道和输入输出重定向。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，以及控制作业的挂起、中止和

2、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(envpathk

3、!= 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,PATH) = 0) while(si != 0) if(si = :) buffj+ = /; buffj = 0; p

4、 = (char *)malloc(strlen(buff) + 1); strcpy(p,buff); envpathk+ = p; envpathk = NULL; j = 0; i+; else buffj = si; j+; i+; else fprintf(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

5、,n; char buf80; if(fd = 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;

6、int li_cmd = 0; int fd101,pipe_in = -1; int pipe_out = -1,flag = 0; pid_t pid; for(i = 0,j = 0,k = 0;i ) | (inputi = n) if(inputi = |) | (inputi = ) if(inputi = ) 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

7、+; k = 0; j = 0; if(j = 0) continue; else bufj+ = 0; if(flag = 0) argvli_cmdk = (char *)malloc(sizeof(char) * j); strcpy(argvli_cmdk,buf); k+; else filename0 = (char *)malloc(sizeof(char) * j); strcpy(filename0,buf); j = 0; else if(inputi = &) & (inputi = 0) is_bg = 1; continue; bufj+ = inputi; argv

8、li_cmdk+ = NULL; for(i = 0;i = 10;i+) fdiFD_READ = NO_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; else pipe

9、_in = NO_PIPE; if(i != li_cmd) pipe_out = fdiFD_WRITE; else if(flag = 1) if(pipe_out = open(filename0,O_WRONLY | O_CREAT | 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_

10、in = NO_PIPE) close(pipe_in); if(pipe_out = NO_PIPE) close(pipe_out); if(pipe_out != 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,0); close(pipe_in); close(pipe_out); return 0;void add_histor

11、y(char * inputcmd) envhis.end = (envhis.end + 1) % HISNUM; if(envhis.end = envhis.start) envhis.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 +

12、 1;i = envhis.end;i+) printf(%dt%sn,j,envhis.his_cmdi); j+; else for(i = envhis.start + 1;i HISNUM;i+) 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 =

13、p - link; while(p != NULL); else printf(No jobs!n);void add_node(char * input_cmd,int node_pid) struct NODE * p; 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; else end - l

14、ink = 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 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

15、- 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() sig_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 =

16、p - link; if(p - pid = pid1) strcpy(p - state,stopped); else add_node(input,pid1); strcpy(end - state,stopped); else add_node(input,pid1); strcpy(end - state,stopped); 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;ou

17、t: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 * p; int i = 0; p = head; for(i = 1;i link; strcpy(p - state,running); strcpy(input,p - cmd); pid1 = p - pid; signal(SIGTSTP

18、,ctrl_z); kill(p - pid,SIGCONT); waitpid(p - pid,NULL,0);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 pid = 0,status = 0; struct sigaction action; action.sa_sigaction = del_node; sigfillset(& action.sa_mask); ac

19、tion.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) ; if(c = n) continue; while(c != n) bufinput_len+ = c; c = getchar(); bufinput_len = 0; input = (char *)malloc(sizeo

20、f(char) * (input_len + 1); strcpy(input,buf); for(i = 0,j = 0,k = 0;i = input_len;i+) if(inputi = ) | (inputi = |) if(inputi = |) pipel(input,input_len); add_history(input); free(input); else redirect(input,input_len); add_history(input); free(input); is_pr = 1; break; if(is_pr = 1) continue; for(i

21、= 0,j = 0,k = 0;i = input_len;i+) if(inputi = ) | (inputi = 0) if(j = 0) continue; else bufj+ = 0; argk = (char *)malloc(sizeof(char) * j); strcpy(argk+,buf); j = 0; else if(inputi = &) & (inputi + 1 = 0) is_bg = 1; continue; bufj+ = inputi; if(strcmp(arg0,exit) = 0) add_history(input); printf(Bye b

22、ye!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+ = inputi; bufj = 0; arg1 = (char *)malloc(sizeof(char) * j); strcpy(arg1,buf); cd_cmd(arg1); free(inpu

23、t); 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(inputi = %) break; i+; for(;i = input_len;i+) bufj+ = inputi; bufj = 0; arg1 = (char *)malloc(sizeof(char) * j); strcpy(arg1,buf);

24、 bg_cmd(atoi(arg1); free(input); continue; if(strcmp(arg0,fg) = 0) add_history(input); for(i = 0;i = input_len;i+) if(inputi = %) break; i+; for(;i = input_len;i+) bufj+ = inputi; bufj = 0; arg1 = (char *)malloc(sizeof(char) * j); strcpy(arg1,buf); fg_cmd(atoi(arg1); free(input); continue; if(is_pr = 0) argk = (char *)malloc(sizeof(char); argk = NULL; if(is_founded(arg0) = 0) printf(This command is not founed!n); for(i = 0;i = k;i+) free(argi);