Dummyshell

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/wait.h>

#define ARGLIMIT 64
#define ARGLENGH 256
#define TRUE 1
#define FALSE 0

#define ETMARGS \
{printf("Fatal error: only 8 arguments are allowed\n"); return 1;}

static int cmd_counter, st;
char *argv[ARGLIMIT];

void init(){
    cmd_counter=0;
    printf("Welcome in Dummyshell!\n");
    fflush(stdout);
}

void leave_shell(void){
    int i;
    if(errno == 0) for(i=0;i<ARGLIMIT-1;i++) free(argv[i]);
    printf("You're leaving Dummyshell...\n");
    fflush(stdout);
}

void type_prompt(){
    printf("[cmd # %d][stat: %d] @ Dush £: ",cmd_counter,st);
    fflush(stdout);
    cmd_counter++;
}

int read_cmd_line(char *argv[]){

    char *arg_buffer = (char*) malloc(sizeof(char)*ARGLENGH), *it;
    int i=0, l1=0, l2=0;

    fgets(arg_buffer,ARGLENGH,stdin);
    fflush(stdin);

    for(it=arg_buffer; it != '\0'; it++){
        if(i >= ARGLIMIT -1) ETMARGS
        argv[i] = (char*) malloc(sizeof(char)*ARGLENGH);
        l1 = strlen(it);
        strncpy(argv[i],it,l1);
        argv[i][l1-1] = '\0';
        it = strchr(it,' ');
        if (it == NULL) break;
        l2 = strlen(it);
        argv[i][l1-l2] = '\0';
        i++;
    }
    argv[i+1] = NULL;
    return 0;
}

int cmd_exit(char *argv[]){
    if(strcmp(argv[0],"exit")==0) return 1;
    return 0;
}

static void execute(int *st, char *argv[]){
    pid_t pid;
    switch(pid=fork()){
        case -1 :{
            perror("Couldn't fork!\n");
            break;
        }
        case 0 :{
            execvp(argv[0],argv);
            perror("Couldn't execute!\n");
            break;
        }
        default :{
            if(waitpid(pid,st,0)==-1){
                perror("Waitpid: ");
                exit(errno);
            }
        }
    }
}

int main(){

    if(atexit(leave_shell)) perror("Atexit failed! Possible memory leak\n");

    init();
    while(TRUE){
        type_prompt();
        if(read_cmd_line(argv)!=-1){
            if(cmd_exit(argv)) exit(EXIT_SUCCESS);
            execute(&st,argv);
        }
        else fprintf(stderr,"Invalid command!\n");
    }
    return 0;
}