utils.c

#include<stdio.h>
#include<stdlib.h>
#include<pwd.h>
#include<signal.h>
#include<unistd.h>
#include<limits.h>
#include<sys/types.h>
#include<string.h>
#include<errno.h>
#include<readline/readline.h>
#include"main.h"
#include"stack.h"

char* makeOperator(char in){
	char *temp = (char*)malloc(3);
	temp[0] = in;
	temp[1] = '\0';
	temp[2] = '\0';
	if(in == 'd'){
		temp[0] = '>';
		temp[1] = '>';
	}
	return temp;
}

void stdErr(char* in){
	if(errno == ENOENT)
		fprintf(stderr, "%s\n", in);
	else
		perror(in);
	return;
}

void releaseMemory(char* param[]){
	int index=0;
	while(param[index] != NULL){
		if(param[index][0] == '>' || 
				param[index][0] == '<' || 
				param[index][0] == '|' || 
				param[index][0] == '&'){
			free(param[index]);
		}
		index++;
	}
}


void checkHomeDir(char* dir){
	char* tempdir;
	if( (tempdir = strstr( dir, "/home")) != NULL){
		if(tempdir == dir){
			int len = strlen(dir);
			int i=5, index=1;
			for(;i<len;i++)
				dir[index++]=dir[i];
			dir[index] = '\0';
			dir[0]='~';
		}
	}
}

char hostname[HOST_NAME_MAX];
char pwd[PATH_MAX];
struct passwd* hostuser;

char* display_prompt(){


	if( gethostname(hostname,HOST_NAME_MAX) != SUCCESS)
		stdErr("Can not get the host name");

	/* hostuser to get both username and the pwd */
	if( (hostuser = getpwuid(getuid()))  == NULL)
		stdErr("Can not get the user info");

	if( getcwd(pwd, PATH_MAX) == NULL)
		stdErr("Can not get the current path");

	checkHomeDir(pwd);
	setenv("SHELL", pwd, 1);

	int lenth = strlen(hostuser->pw_name)+strlen(pwd)+9;
	char *out;

	if((out = (char*)malloc(lenth)) == NULL)
		stdErr("Can not allocate space");
	strcpy(out, hostuser->pw_name);
	strcat(out, "@sish:");
	strcat(out, pwd);
	strcat(out, "$ ");

	return out;
}

char cmd[ARG_MAX];

int sperateCMD(char* in){
	int i=0;
	int len = strlen(in);
	/* flag to determine if we should skip the space in 
	   a string */
	int findQuote = 0;
	/* Stack to valid the quotes pair */
	Stack	stk;
	Stack_Init(&stk);

	for(; i<len; i++){
		if(in[i] == ' ' && !findQuote)
			in[i]='\0';
		if( in[i] == '\'' || in[i] == '\"' ){

			if( stk.size > 0 && Stack_Top(&stk) == in[i])
				Stack_Pop(&stk);
			else
				Stack_Push(&stk,in[i]);
			findQuote++;
			if(stk.size == 0)
				findQuote = 0;
			in[i] = '\0';
		}
	}
	return len;
}

int read_cmd(char* in, char* param[]){
	
	
	char *tempCmd;
		
	if(!cflg)
		tempCmd  = readline(in);
	int paraNum;
	/* Handle the non-input in cmd */
	
	if(!cflg){
		free(in);
		in = tempCmd;
	}

	if( in == NULL || strlen(in) == 0){
		param[0] = in;
		return 0;
	}

	if( strcpy(cmd,in) == NULL)
		stdErr("err in strycpy()");

	int length = sperateCMD(cmd);
	if( length < 0){
		cmd[0] = '\0';
	}
	else{
		int i=0, index=1;
		for(i=0; i< length; i++)
			if(cmd[i]!='\0'){
				param[0] = &cmd[i];
				break;
			}

		/* skip the space before the first char in cmd*/
		int firstItem = i;
		for(i = firstItem+1; i< length; i++){
			if(cmd[i] == '>' || cmd[i] == '<' || cmd[i] == '|' || cmd[i] == '&'){
				if(cmd[i+1] == '>' && cmd[i] == '>'){
					param[index++] = makeOperator('d');
					cmd[i+1] = '\0';cmd[i]='\0';
				}
				else{
					param[index++] = makeOperator(cmd[i]);
					cmd[i] = '\0';
				}
			}
			else if(cmd[i] != '\0' && cmd[i-1] == '\0')
				param[index++] = &cmd[firstItem]+i;
		}
		paraNum = index;
	}
	return paraNum;
}


int buildin_cmd(char* in, char *param[]){
	in = param[0];

	if( strcmp(in,"exit")==0 ){
		if(xflg)
			fprintf(stderr,"+ exit\n");
		exit(0);
	}
	
	if( strcmp(param[0],"cd")==0 ){
		if(xflg){
			fprintf(stderr,"+ %s", param[0]);
			if(param[1] != NULL)
				fprintf(stderr," %s\n", param[1]);
			else
				fprintf(stderr, "\n");
		} 
		if(param[1] == NULL){
			chdir("/home");
			return 1;
		}
		if(strcmp(param[1],".") == 0 ){
			return 1;
		}
		if( strcmp(param[1],"..") == 0){
			if(chdir("../") < 0)
				stdErr("No such directory.");
		}
		else{
			if(chdir(param[1]) < 0)
				stdErr("No such directory.");
		}

		return 1;	
	}
	return 0;
}