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shell.c
160 lines (141 loc) · 3.7 KB
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shell.c
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#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <termios.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <stdbool.h>
#define INPUT_STRING_SIZE 80
#include "io.h"
#include "parse.h"
#include "process.h"
#include "shell.h"
int cmd_quit(tok_t arg[]) {
printf("Bye\n");
exit(0);
return 1;
}
int cmd_help(tok_t arg[]);
/* Command Lookup table */
typedef int cmd_fun_t (tok_t args[]); /* cmd functions take token array and return int */
typedef struct fun_desc {
cmd_fun_t *fun;
char *cmd;
char *doc;
} fun_desc_t;
fun_desc_t cmd_table[] = {
{cmd_help, "?", "show this help menu"},
{cmd_quit, "quit", "quit the command shell"},
};
int cmd_help(tok_t arg[]) {
int i;
for (i=0; i < (sizeof(cmd_table)/sizeof(fun_desc_t)); i++) {
printf("%s - %s\n",cmd_table[i].cmd, cmd_table[i].doc);
}
return 1;
}
int lookup(char cmd[]) {
int i;
for (i=0; i < (sizeof(cmd_table)/sizeof(fun_desc_t)); i++) {
if (cmd && (strcmp(cmd_table[i].cmd, cmd) == 0)) return i;
}
return -1;
}
char *concat(char *str1, char *str2) {
char *s = malloc(strlen(str1)+strlen(str2)+1);
s=strcpy(s,str1);
s=strcat(s,str2);
return s;
}
void init_shell()
{
/* Check if we are running interactively */
shell_terminal = STDIN_FILENO;
/** Note that we cannot take control of the terminal if the shell
is not interactive */
shell_is_interactive = isatty(shell_terminal);
if(shell_is_interactive){
/* force into foreground */
while(tcgetpgrp (shell_terminal) != (shell_pgid = getpgrp()))
kill( - shell_pgid, SIGTTIN);
shell_pgid = getpid();
/* Put shell in its own process group */
if(setpgid(shell_pgid, shell_pgid) < 0){
perror("Couldn't put the shell in its own process group");
exit(1);
}
/* Take control of the terminal */
tcsetpgrp(shell_terminal, shell_pgid);
tcgetattr(shell_terminal, &shell_tmodes);
}
/** YOUR CODE HERE */
}
/**
* Add a process to our process list
*/
void add_process(process* p)
{
/** YOUR CODE HERE */
}
/**
* Creates a process given the inputString from stdin
*/
process* create_process(char* inputString)
{
/** YOUR CODE HERE */
return NULL;
}
int shell (int argc, char *argv[]) {
char *s = malloc(INPUT_STRING_SIZE+1); /* user input string */
tok_t *t;
int status = 0; /* tokens parsed from input */
int lineNum = 0;char *fi1;
int fundex = -1;
int MAX_NUM = 10000;
char nyawa[MAX_NUM];
pid_t pid = getpid(); /* get current processes PID */
pid_t ppid = getppid(); /* get parents PID */
pid_t cpid, tcpid, cpgid;
init_shell();
printf("%s running as PID %d under %d\n",argv[0],pid,ppid);
lineNum=0;
fprintf(stdout, "%d: %s:", lineNum, getcwd(nyawa,sizeof(nyawa)));
while ((s = freadln(stdin))){
t = getToks(s); /* break the line into tokens */
fundex = lookup(t[0]); /* Is first token a shell literal */
if(fundex >= 0) cmd_table[fundex].fun(&t[1]);
else {
pid_t pid = fork();
if (pid ==-1)
{
perror("cmd");
exit(1);
}
else if(pid == 0)
{
tok_t *fi;
char *fi1=getenv("PATH");
fi = getToks(fi1);
for(int i = 0;i<MAXTOKS && fi[i];i++){
char *char1 =concat(fi[i],"/");
char1 =concat(char1,t[0]);
if(access(char1,F_OK) != -1){
execve(char1,t, NULL);
}
}
execvp(*t,t);
perror(*t);
exit(0);
}
else
{
while ((pid != wait(&status)));
}
}
fprintf(stdout, "%d: %s :",++lineNum,getcwd(nyawa,sizeof(nyawa)));
}
return 0;
}