Minix系统shell命令解释器

/*name: panruoying*/ /*number: 5060309237*/ #include <stdio.h> #include <unistd.h> #include <sys/types.h> #include <string.h> #include <stdlib.h> #include <unistd.h> #include <sys/wait.h> #include <sys/stat.h> #include <fcntl.h> #include <errno.h> #define MAXSIZE 99 int main(void) { char *readCommand(char *buffer); /*get command from keyboard*/ int isPipe(const char *input); /*get the number of pipes*/ int pipel(char * input); /*the function of pipe*/ int redirect(char *input); /*redirect of I/O*/ char *path,*buffer; char *thecommand; int i,pipe,k; buffer=(char *)malloc(MAXSIZE*(sizeof(char))); while(1) { path=getcwd(NULL,0); /*get the present path*/ printf("%%pry Shell%%"); thecommand=readCommand(buffer); /*read the command*/ if(thecommand==NULL) continue; if(strlen(thecommand)!=0) { k=isPipe(thecommand); /*whether there is pipe*/ if(k!=0) pipel(thecommand); else redirect(thecommand); /*redirect I/O*/ } /*release the memory space*/ free(thecommand); free(path); } } char *readCommand(char *buffer) /*get the command from keyboard*/ { char temp_char; char *input; int k=0; temp_char = getchar(); while(temp_char != '\n' && k < MAXSIZE) { buffer[k] = temp_char; temp_char = getchar(); k++; } if(k >= MAXSIZE) /*error when the command is overlong*/ { fprintf(stderr,"Opps! Your command is too long ! -_-b\n"); k = 0; return NULL; } else buffer[k] = '\0'; /*add the character of EOF to form a string*/ input=(char *)malloc(sizeof(char)*(k+1)); strcpy(input, buffer); return input; } int isPipe(const char *input) /*get the number of pipes*/ { int i; for (i=0;i<strlen(input);i++) if(input[i]=='|') return 1; return 0; } int pipel(char * input) /*the function of pipe*/ { int redirect(char *input); int isDaemon(char *command); /*whether the process is daemon and delete the "&"*/ int isPipe(const char *input); /*get the number of pipes*/ int status,i,j,k,*fd,back=0,len; char **command; int *child; back=isDaemon(input); len=strlen(input); command=(char **)malloc(2*sizeof(char *)); for(i=0;i<2;i++) command[i]=(char *)malloc((len+1)*sizeof(char)); child=(int *)malloc(2*sizeof(char *)); fd=(int *)malloc(2*sizeof(int)); /*get the two commands of the pipe*/ k=0; j=0; for (i=0;i<=len;i++) { if (input[i]!='|') { command[k][j]=input[i]; j++; } else { command[k][j]='\0'; k++; j=0; } } /*create the pipe*/ pipe(fd); /*create the first child*/ if((child[0]=fork())==0) { close(fd[0]); if(fd[1] != STDOUT_FILENO) { /*redirect the STD_OUT to the write_end of pipe,*/ /*so that the output of the subprocess is writtern into pipe*/ dup2(fd[1], STDOUT_FILENO); close(fd[1]); } redirect(command[0]); exit(1); } else { /*wait for child*/ waitpid(child[0],&status,0); close(fd[1]); } /*create the second child*/ if((child[1] = fork()) == 0) { close(fd[1]); if(fd[0] != STDIN_FILENO) { /*redirect the STD_IN to the read_end of pipe*/ dup2(fd[0], STDIN_FILENO); close(fd[0]); } redirect(command[1]); exit(1); } else if(back==0) { waitpid(child[1], NULL, 0); close(fd[1]); } /*release the memory space*/ free(fd); for(i=0;i<2;i++) free(command[i]); free(command); free(child); return 1; } int redirect(char *input) /*function of redirection of I/O*/ { char **analize(const char *input); /*analyse the commands, get them and their arguments and store them in args*/ char *isFileExist(const char *command); /*judge if the command exit or not*/ void doCd(char *argv[]); /*the command that used particularly for "cd"*/ int number(const char *input); /*analyse the command, get the number of its arguments, and devide the string*/ int isDaemon(char *command); /*whether the process is daemon and delete the "&"*/ char *command_path,*real_command; char *out_filename,*in_filename; char **analized_command; int len,status,i,j,k,back=0,fd_out,fd_in,flag_out=0,flag_in=0; pid_t pid; back=isDaemon(input); len=strlen(input); out_filename=(char *)malloc((len+1)*(sizeof(char))); in_filename=(char *)malloc((len+1)*(sizeof(char))); real_command=(char *)malloc((len+1)*(sizeof(char))); /*read the command from the string, and store it in real_command */ for(i=0;i<len;i++) { if (input[i]!='>'&&input[i]!='<') real_command[i]=input[i]; else { if (input[i]=='>') flag_out=1; if (input[i]=='<') flag_in=1; break; } } real_command[i]='\0'; i++; /*read the whitespace in front*/ while ((input[i]==' '||input[i]==' ')&&i<len) i++; j=0; out_filename[0]='\0'; in_filename[0]='\0'; /*read the direct-in or direct-out file*/ if(flag_out>0) { while (i<=len) { if(input[i]=='<') { out_filename[j]='\0'; break; } out_filename[j]=input[i]; i++; j++; } } if(flag_in>0) while (i<=len) { if (input[i]=='>') { in_filename[j]='\0'; break; } in_filename[j]=input[i]; i++; j++; } /*there are both redirect of in and redirect of out*/ if (i<len) { j=0; if (flag_out>0&&input[i]=='<') { i++; flag_in=1; /*read the whitespace in front*/ while ((input[i]==' '||input[i]==' ')&&i<len) i++; while (i<=len) { in_filename[j]=input[i]; i++; j++; } } else if (flag_in>0&&input[i]=='>') { i++; flag_out=1; /*read the whitespace in front*/ while ((input[i]==' '||input[i]==' ')&&i<len) i++; while (i<=len) { out_filename[j]=input[i]; i++; j++; } } else { fprintf(stderr,"Oops!can't find the file! -_-b\n"); return -1; } } k=number(real_command); analized_command=analize(real_command); /*the command has been stored in *analized_command*/ if(strcmp(analized_command[0], "leave") == 0) /*the command of exit*/ { printf("THX for using~ wave~~~\n"); /*release the memory space*/ for(i=0;i<k;i++) free(analized_command[i]); free(analized_command); free(real_command); exit(1); return 1; } /*if the command is cd*/ if (strcmp(analized_command[0],"cd")==0) { doCd(analized_command); /*release the memory space*/ for(i=0;i<k;i++) free(analized_command[i]); free(analized_command); free(real_command); return 1; } command_path=isFileExist(analized_command[0]); if(command_path==NULL) /*can't find the command*/ { fprintf(stderr,"Oops! This command is not founded...... -_-b\n"); /*release the memory space*/ for(i=0;i<k;i++) free(analized_command[i]); free(analized_command); free(real_command); return -1; } pid = fork(); if(pid == 0) /*child process*/ { /*there is the redirect of I/O*/ if(flag_out==1) fd_out = open(out_filename,O_WRONLY|O_CREAT|O_TRUNC, S_IRUSR|S_IWUSR ); if(flag_in==1) fd_in = open(in_filename, O_RDONLY, S_IRUSR|S_IWUSR ); if(fd_out==-1) { printf("Oops! Open out %s error -_-b\n", out_filename); return -1; } if(fd_in==-1) { fprintf(stderr,"Oops! Open in %s error -_-b\n", in_filename); return -1; } /*redirect the STD_OUT to the fd_out by dup2*/ if(flag_out>0) dup2(fd_out, STDOUT_FILENO); /*redirect the STD_IN to the fd_in by dup2*/ if(flag_in>0) dup2(fd_in,STDIN_FILENO); execv(command_path,analized_command); exit(1); } else /*parent process */ if(back==0) /*it is not the daemon process*/ pid=waitpid(pid, &status, 0); /*release the memory space*/ free(out_filename); free(in_filename); free(command_path); for(i=0;i<k;i++) free(analized_command[i]); free(analized_command); return 1; } int isDaem