лабораторки по ОС препод Челноков / 2семестр / wi2 / zubanov / qw / Shell_03

#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/wait.h>
#include <sys/types.h>
#include <fcntl.h>
#include <signal.h>

#define EXIT 0
#define PROGRAM 1
#define CAT 2
#define ECHO 3
#define OR 4
#define AND 5
#define IN 6
#define OUT 7
#define CONV 8

static int status=0;
static int count=0; 

int filestart(char *file_param[])
{
	int pid,stat_loc;
	pid=fork();
	if (pid<0)
	{
		printf(" ! Error fork\n");
		return -1;
	}
	else
	if (pid==0)
	{
		execvp(file_param[0],file_param);
		printf(" ! Can not execute %s\n",file_param[0]);
		kill(getpid(),SIGKILL);
	}
	else
	{
		wait(&stat_loc);
		return (stat_loc>>8);
	}
}

int detect(char *com[],char *cmd_param[])//DETECTION
{
	int id_com,i=0;
	int fd_buf,fd_in;
	while (com[count]!=NULL)
	{

		if (id_com=strcmp(com[count],"exit")==0)
		{
			return EXIT;
		}
		else
		if (id_com=strcmp(com[count],"cat")==0)
		{
			cmd_param[0]=com[count+1];
			count++;
			return CAT;
		}
		else
		if (id_com=strcmp(com[count],"echo")==0)
		{
			while (com[count+1]!=NULL)
			{
				count++;
				cmd_param[i]=com[count];
				i++;
			}
			count++;
			cmd_param[i]=NULL;
			return ECHO;
		}
		else
		{
		    while(com[count]!=NULL)
		    {
			if (id_com=strcmp(com[count],"||")==0)
			{
			    cmd_param[i]=0;
			    status=filestart(cmd_param);
			    count++;
			    return OR;
			}
			if (id_com=strcmp(com[count],"&&")==0)
			{
			    cmd_param[i]=0;
			    status=filestart(cmd_param);
			    count++;
			    return AND;
			}
			if (id_com=strcmp(com[count],">")==0)
			{
			    cmd_param[i]=NULL;
			    fd_buf=dup(1);
			    close(1);
			    count++;
			    fd_in=open(com[count],O_RDWR|O_CREAT);
			    status=filestart(cmd_param);
			    dup2(fd_buf,1);
				
			    return IN;
			}
			if (id_com=strcmp(com[count],"<")==0)
			{
			    cmd_param[i]=NULL;
			    fd_buf=dup(0);
			    close(0);
			    count++;
			    fd_in=open(com[count],O_RDONLY);
			    status=filestart(cmd_param);
			    dup2(fd_buf,0);
				
			    return OUT;
			}
			if (*com[count]=='|')
			{
			    cmd_param[i]=NULL;
			    count++;
			    return CONV; 
			}
			cmd_param[i]=com[count];
			i++;
			count++;
		    }
		    cmd_param[i]=NULL;
		    return PROGRAM;
		}	
		
	}
	
}

int len_com(char *data_buf)
{
	int len=0;
	while(*data_buf)
	{
		data_buf++;
		len++;
	}
	return len+1;
}

main()
{
	char data_buf[1000];
	char *commands[100];
	char *cmd_param[99];
	char *xx[2];
	char *next_com;
	char sym;
	int  command,s_det,i=0;
	FILE *fd;
	int std_in,std_out,buf,buf1;
	int fdes[2];
	xx[1]=NULL;
	while (1)
	{//MAIN

		printf("$");//insert
		commands[0]=next_com=data_buf;
		count=0; 
		do
		{
			scanf("%s",next_com);
			sym=getchar();
			count++;
			next_com+=len_com(next_com);
			commands[count]=next_com;
		}
		while (sym!='\n');//insert 
		commands[count]=NULL;
		count=0;

		
		
		    command=detect(commands,cmd_param);
		    switch (command)
		    {
		    case EXIT:
			    return 0;
			    break;

		    case CAT:
			    fd=fopen(cmd_param[0],"r");
			    if (fd==NULL) 
			    {
				    printf("Error of read in %s\n",cmd_param[0]);
				    break;
			    }
			    i=0;
			    while ((sym=getc(fd))!=EOF)
			    {
				    printf("%c",sym);
				    i++;
				    if ((i%12)==0) printf("\n");
			    }
			    printf("\n");
			    fclose(fd);
			    break;

		    case ECHO:
			    i=0;
			    if (s_det=strcmp(cmd_param[i+1],"$?")==0)
			    {
				 printf("%d\n",status);
				 i++;
			     }
			    while (cmd_param[i]!=NULL)
			    {
				    printf("%s ",cmd_param[i]);
				    i++;
			    }	
			    printf("\n");
			    break;
		    case OR:
				xx[0]=commands[count];
			    if (status==0) command=filestart(xx);
			    break;
		    case AND:
				xx[0]=commands[count];
			    if (status!=0) command=filestart(xx);
			    break;
		    case CONV:
			    buf=dup(1);
			    buf1=dup(0);
			    std_in=dup(0);
			    do 
			    {
				pipe(fdes);    
				std_out=fdes[1];
				dup2(std_in,0);
				dup2(std_out,1);
				close(std_in);
				close(std_out);
				s_det=filestart(cmd_param);
				std_in=fdes[0];
			    }
			    while (s_det=detect(commands,cmd_param)==CONV);
		case PROGRAM:
			    dup2(buf,1);
			    dup2(std_in,0);
			    s_det=filestart(cmd_param);
			    dup2(buf1,0);
			    break;
		    			   
		    }
		
	}//MAIN
	return 1;
}