utility.c

这是一个shell的实现程序。其中System的实现参考了linux的。不好意思哈。

#include "myshell.h"


void printPrompt()
{
	char buf[MaxCommandLine];
	char buf1[MaxCommandLine+2];
	char * promptStr = getcwd(buf,sizeof(buf));
	
	if( !promptStr )
	{
		sprintf(buf,"<null>");
		promptStr = buf;
	}
	else
	{
		sprintf(buf1,"%s::",buf);
		promptStr = buf1;
	}

	if ( write(STDOUT_FILENO, promptStr, strlen(promptStr) )!=strlen(promptStr))
	{
		errhandle("cannot write to stdout");
	}
}

void errhandle(char* msg)
{
	perror(msg);
	exit(1);
}




int execute(const char *cmd)
{
	int stat;
	pid_t pid;
	struct sigaction sa, savintr, savequit;
	sigset_t saveblock;
	if (cmd == NULL)
		return(1);
	sa.sa_handler = SIG_IGN;
	sigemptyset(&sa.sa_mask);
	sa.sa_flags = 0;
	sigemptyset(&savintr.sa_mask);
	sigemptyset(&savequit.sa_mask);
	sigaction(SIGINT, &sa, &savintr);
	sigaction(SIGQUIT, &sa, &savequit);
	sigaddset(&sa.sa_mask, SIGCHLD);
	sigprocmask(SIG_BLOCK, &sa.sa_mask, &saveblock);
	if ((pid = fork()) == 0) {
		sigaction(SIGINT, &savintr, (struct sigaction *)0);
		sigaction(SIGQUIT, &savequit, (struct sigaction *)0);
		sigprocmask(SIG_SETMASK, &saveblock, (sigset_t *)0);
		execl("/bin/sh", "sh", "-c", cmd, (char *)0);
		_exit(127);
	}
	if (pid == -1) {
		stat = -1; /* errno comes from fork() */
	} else {
    	while (waitpid(pid, &stat, 0) == -1) {
    		if (errno != EINTR){
    			stat = -1;
    			break;
    		}
    	}
    }
	sigaction(SIGINT, &savintr, (struct sigaction *)0);
	sigaction(SIGQUIT, &savequit, (struct sigaction *)0);
	sigprocmask(SIG_SETMASK, &saveblock, (sigset_t *)0);
	return(stat);
}



int newEnvironParams(const char * name,const char * value)
{
	return	setenv(name,value,1);
}


void InitEnvironParams()
{	
	char buf[MaxCommandLine];
	char buf2[MaxCommandLine*2];
	char * str = getenv("shell");
	char * pwd = getcwd(buf,sizeof(buf));
	
	if(!pwd)
	{
		return;
	}

	if(!str)
	{
//		printf("shell params do not exist.\n");
		sprintf(buf2,"%s",buf);
	}
	else
	{
//		printf("shell params exist.\n");
		sprintf(buf2,"%s;%s",str,buf);
	}

	unsetenv("shell");
	newEnvironParams("shell",buf2);
	
	newEnvironParams("parent",buf2);

}


void quitShell(char* params[], int paramNumber)
{
	exit(0);
}



void changeDir(char* params[], int paramNumber)
{
	if (paramNumber!=2)
	{
//		int i = 0;
//		for( i =0 ; i< paramNumber ; i++)
//			printf("--%s--%d\n",params[i],paramNumber);
		printf(helpStr);
	}
	else
	{
		if (chdir(params[1])<0)
		{
			if (errno==ENOTDIR||errno==ENOENT)
			{		
				char buf[MaxCommandLine];
				getcwd(buf,MaxCommandLine);
				printf("The directory %s does not exist\nThe Current Directory is %s\n", params[1],buf);
			}
		}
	}
}

void dodir(char* path,FILE * fp)
{
	DIR* dp;
	struct dirent* dirnode;
	if ((dp=opendir(path))!=NULL)
	{
		while ((dirnode=readdir(dp))!=NULL)
		{
			if(fp)
			{
				fwrite(dirnode->d_name,strlen(dirnode->d_name),1,fp);
				fwrite("\n",1,1,fp);
			}
			else
				printf("%s\n", dirnode->d_name);
		}
	}
	else
	{
		char buf[MaxCommandLine];
		char buf2[MaxCommandLine*2];
		getcwd(buf,MaxCommandLine);
		sprintf(buf2,"The directory %s does not exist. \nThe Current directory:%s\n", path, buf);
		if(fp)
		{
			fwrite(buf2,strlen(buf2),1,fp);
			fwrite("\n",1,1,fp);
		}
		else
			printf("%s\n", dirnode->d_name);
	}
}

void listDir(char* params[], int paramNumber)
{
	int index0 = -1;
	FILE * fhandle = NULL;
	int outputtype = outputDirect(params,paramNumber,&index0);
	if( index0 >= paramNumber)
	{
		printf("Something Wrong. Please contact [e-mail].\n");
		return;
	}

	switch(outputtype)
	{
		case 1:
			if( index0 == -1 )
			{
				break;							
			}
			fhandle = fopen(params[index0],"w");
			break;
		case 2:
			if( index0 == -1 )
			{
				break;
			}
			fhandle = fopen(params[index0],"a");
			break;
		case 0:
		default:
			break;
	}


	if ( (paramNumber==3 && outputtype) || paramNumber == 1)
	{
		dodir(".",fhandle);
	}
	else
	{
		dodir(params[1],fhandle);
	}

	if(fhandle)
		fclose(fhandle);
}
		

void clrFile(char* params[], int paramNumber)
{
	 execute("clear");
}

void environFile(char* params[], int paramNumber)
{
	int index0 = -1;
	int outputtype = outputDirect(params,paramNumber,&index0);
	if( index0 >= paramNumber)
	{
		printf("Something Wrong. Please contact [e-mail].\n");
		return;
	}

	char str[MaxCommandLine];
	switch(outputtype)
	{
		case 1:
			if( index0 == -1 )
			{
				sprintf(str,"set");					
			}
			sprintf(str,"set > %s",params[index0]);
			break;
		case 2:
			if( index0 == -1 )
			{
				sprintf(str,"set");					
			}
			sprintf(str,"set >> %s",params[index0]);			
			break;
		default:
			sprintf(str,"set");		
			break;
	}

	execute(str);

}

void echoFile(char* params[], int paramNumber)
{
	int i = 0;
	
	int index0 = -1;
	FILE * fhandle = NULL;
	int outputtype = outputDirect(params,paramNumber,&index0);
	if( index0 >= paramNumber)
	{
		printf("Something Wrong. Please contact [e-mail].\n");
		return;
	}


	char str[MaxCommandLine];
	switch(outputtype)
	{
		case 1:
			if( index0 == -1 )
			{
				for( i=1 ; i < paramNumber ; i++ )
				{
					printf("%s ",params[i]);
				} 
				printf("\n");
				break;							
			}
			fhandle = fopen(params[index0],"w");
			for( i=1 ; i < index0 - 1 ; i++ )
			{
				fwrite(params[i],strlen(params[i]),1,fhandle);
				fwrite(" ",1,1,fhandle);
			} 
			fclose(fhandle);
			break;
		case 2:
			if( index0 == -1 )
			{
				for( i=1 ; i < paramNumber ; i++ )
				{
					printf("%s ",params[i]);
				} 
				printf("\n");
				break;	
			}
			fhandle = fopen(params[index0],"a");
			for( i=1 ; i < index0 - 1  ; i++ )
			{
				fwrite(params[i],strlen(params[i]),1,fhandle);
				fwrite(" ",1,1,fhandle);
			} 
			fclose(fhandle);			
			break;
		default:
			for( i=1 ; i < paramNumber ; i++ )
			{
				printf("%s ",params[i]);
			} 
			printf("\n");			
			break;
	}
	
}

void helpFile(char* params[], int paramNumber)
{
//	printf(helpStr);
	int index0 = -1;
	FILE * fhandle;
	int outputtype = outputDirect(params,paramNumber,&index0);
	if( index0 >= paramNumber)
	{
		printf("Something Wrong. Please contact [e-mail].\n");
		return;
	}


	char str[MaxCommandLine];
	switch(outputtype)
	{
		case 1:
			if( index0 == -1 )
			{
				execute("more readme");							
			}
			fhandle = fopen(params[index0],"w");
			fwrite(helpStr,strlen(helpStr),1,fhandle);
			fclose(fhandle);
			break;
		case 2:
			if( index0 == -1 )
			{
				execute("more readme");
			}
			fhandle = fopen(params[index0],"a");
			fwrite(helpStr,strlen(helpStr),1,fhandle);
			fclose(fhandle);			
			break;
		default:
			execute("more readme");			
			break;
	}


}

void pauseFile(char* params[], int paramNumber)
{
	char buf[MaxCommandLine];
	char str[] = "enter";
	int n;

	printf("To continue, please press \'enter\' command:\n");
	memset(buf,0,sizeof(buf));
	while ((n=read(STDIN_FILENO, buf, MaxCommandLine))>0)
	{
		if(	(n=strcmp(buf, str)) >= 0)
		{
			break;
		}
		else
		{
			printf("enter error%d,%s\n",n,buf);
			printf("To continue, please press \'enter\' command:\n");
		}
		memset(buf,0,sizeof(buf));
	}
}

//The returned value presents the type of output direction.
//1 means '>'
//2 means '>>'
//0 means no output direction.
//The returned param fileIndex is behalf of the index number in params of the output file name.
int outputDirect(char* params[], int paramNumber, int * fileIndex)
{
	int i = 0;
	
	for( i=1 ; i < paramNumber ; i++ )
	{
		if (strcmp(params[i],">>") == 0) 
		{
			if(i+1 < paramNumber )
			{
				*fileIndex = i+1;
				return 2;
			}
		}
		else
		if	(strcmp(params[i],">") == 0) 
		{
			if ( i+1 < paramNumber )
			{
				*fileIndex = i+1;
				return 1;
			}
		}
	} 
	
	return 0;
}



void inputDirect(char* params[], int paramNumber)
{
	int i = 0;
	int nIndex = -1;

	printf("xxxx%d \n",paramNumber);
	
	for( i=1 ; i < paramNumber ; i++ )
	{
		if	(strcmp(params[i],"<") == 0) 
		{
			if ( i+1 < paramNumber )
			{
				nIndex = i+1;
			}
		}
	} 
	
	//It means that no input redirection exists. return 0;
	if( nIndex == -1 )
	{
		printf("no input redirection!\n");
		return ;
	}

	printf("input redirection ok!\n");

	
	return ;
}



int ampersandFunc(char* cmdStr)
{
	int n, paramNumber;
	int commandType;
	char* params[MaxParamNumber];


	pid_t pID = fork();
	if (pID == 0)                // child
	{
		strtok(cmdStr, "&");
//		printf("+---%s\n",cmdStr);
		commandType=parseCommand(cmdStr, params, &paramNumber);
		switch (commandType)
		{
			case -2:
				printf("illegal command params.\n%s");
				break;
			case -1:
				printf("The command \'%s\' is executed by /bin/shell\n",cmdStr);
				execute(cmdStr);
				break;
			case -3:
				break;
			default:	
				commandArray[commandType](params, paramNumber);			
			break;
		}
		_exit(127);
	}
	else if (pID < 0)            // failed to fork
	{
		printf("Failed to fork");
		exit(1);
	}
	
	return 0;
}