/* --------------------------------------------------
This function processes the input. It will check for special cases:
-------------------------------------------------- */
void processInput(){
int i;
//Check for &. If present, it should be run in the bg. Flip BG flag, then flush that array element to NULL
if(strcmp(CARGV[CARGC - 1], "&") == 0){
BG = true;
CARGV[CARGC - 1] = NULL;
CARGC--;
//printf("background = true\n");
}
//Check for <. If present, we will need to change stdin to the input file. Keep track of that in INPF
for(i = 0; i < CARGC; ++i){
if(strcmp(CARGV[i], "<") == 0){
INP = true; //Flip flag
INPF = malloc(sizeof(char) * 25); //Make memory for INPF
INPF = CARGV[i + 1]; //Put the file name in INPF
CARGV[i] = NULL; //Wipe these array locations since we have the info.
CARGV[i+1] = NULL;
CARGC = CARGC -2; //New number of arguments.
}
}
//Check for >. If present, we will need to change stdout to the output file. Keep track of that in OUTPF
for(i = 0; i < CARGC; ++i){
if(strcmp(CARGV[i], ">") == 0){
OUTP = true; //Flip flag
OUTPF = malloc(sizeof(char) * 25); //Make memory for OUTPF
OUTPF = CARGV[i + 1]; //Put the file name in OUTPF
CARGV[i] = NULL; //Wipe these array locations since we have the info.
CARGV[i+1] = NULL;
CARGC = CARGC -2; //Lower the number of command arguments.
}
}
//Check to see if the command that remains is one of the built in.
if(checkBuiltIn() == 0){
callNative(); //If its not, try calling a native command.
}
return;
}
int main(){
/* The raw input is stored in a buffer. The locations of the first character
* of the tokens and the pipes is given by a pointer*/
char input[INPUT_BUFFER];
char* tokens[MAX_TOKENS];
char* pipes[MAX_TOKENS];
int numTokens;
int numPipes;
/* Assign names and function pointers to the global array above*/
buildFunctionTable();
while(1){
/* See header for more info. This function prompts the user for input.
* a return of -1 means no non-whitespace input*/
if(getInput(input)==-1){
continue;
}
/* Break the input into tokens and pipes. Return an error code for
* different types of invalid input (or 0 on good input) */
int valid = parseInput(input, tokens, pipes, &numTokens, &numPipes);
if(valid<0){
switch(valid){
case LINE_ENDING_INVALID:
fprintf(stderr, "Error: There was an issue with line endings\n");
break;
case MAX_ARGS_ERROR:
fprintf(stderr, "Error: Too many arguments\n");
break;
case QUOTE_ERROR:
fprintf(stderr, "Error: Unmatched Quotes\n");
break;
default:
fprintf(stderr, "Error: Invalid Input\n");
break;
}
continue;
}
/* If there's more than one command, check for built-in commands first
* and then set up to execute an external command */
if(numTokens > 0){
if(checkBuiltIn(tokens,numTokens)!=0){
int pid;
pid = fork();
if(pid==0){
/* The child runs the command */
runCommands(tokens,pipes,numTokens,numPipes);
exit(0);
}else if(pid == -1){
perror("fork");
}else{
/* The parent gives the return message */
waitAround(pid);
}
}
}
}
return 0;
}