csc360-a1-shell/c/builtins.c

/*
 * A simple shell with some basic features.
 *
 * Sami Samhuri 0327342
 * January 31, 2006
 * CSC 360, Assignment 1
 *
 * builtins.c
 * $Id: builtins.c 184 2006-01-29 08:53:30Z sjs $
 */

/*#define _GNU_SOURCE*/
 
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>

#include "builtins.h"
#include "main.h"
#include "exec.h"
#include "jobs.h"
#include "utils.h"

int builtin_bg ( int argc, char **argv )
{
	if ( argc < 2 )
	{
		queue_message ("bg: usage 'bg <command>'");
		queue_message ("    runs <command> in the background");
		return -1;
	}

	pid_t pid = exec_command (&argv[1], 1); /* &argv[1] skips 'bg' */
	if (pid > 0)
	{
		job j = add_job (pid, &argv[1]);
	
		char *message = (char *)myxmalloc (MSGLEN);
		snprintf (message, MSGLEN,
				  "Running job " YELLOW "%i" WHITE " (pid %i) in background" CLEAR,
				  j->id, pid);
		queue_message (message);
		free (message);
	}
	return pid;
}

int builtin_bgkill ( int argc, char **argv )
{
	if ( argc != 2 )
	{
		queue_message ("bgkill: usage 'bgkill <job number>'");
		queue_message ("        type 'bglist' to see running jobs");
		return -1;
	}

	int job_id = atoi (argv[1]);
	job j = job_with_id (job_id);
	if (!j)
	{
		queue_message (YELLOW "Invalid job number");
		queue_message ("(type 'bglist' to see running jobs)");
		return -1;
	}

	kill (j->pid, SIGTERM);
	/*delete_job (j);*/
/*	queue_message ("Job killed");*/
	return 1;
}

int builtin_bglist ( void )
{
	int num_jobs;
	if ( !(num_jobs = get_num_jobs()) )
		return 0;

	job j;
	char *message = (char *)myxmalloc (MSGLEN);
	for (j = get_job_list(); j; j = j->next)
	{
		snprintf (message, MSGLEN,
				  YELLOW "%i" WHITE ": (pid %i)" YELLOW " %s" CLEAR,
				  j->id, j->pid, j->cmdline);
		queue_message (message);
	}
	snprintf (message, MSGLEN,
			  GREEN "Total: %i background job(s) running" CLEAR, num_jobs);
	queue_message (message);
	free (message);
	return num_jobs;
}

int builtin_cd ( int argc, char **argv )
{
	static char *lastdir = NULL;
	char *dir, *pwd = getcwd(NULL, 0);

	if (!lastdir)				/* initialize */
		lastdir = pwd;

	if ( argc < 2 )				/* cd w/ no args acts like cd $HOME */
		dir = getenv("HOME");
	else
	{
		if ( !strncmp(argv[1], "-", 1) )
			dir = lastdir;		/* cd - changes to previous dir */
		else
			dir = argv[1];
	}

	if ( chdir (dir) < 0 )
	{	/* error */
		size_t len = strlen (dir);
		char *message = (char *)myxmalloc (len + MSGLEN);
		(void) snprintf (message, len + MSGLEN,
						 RED "cd: %s: %s" CLEAR, strerror (errno), dir);
		queue_message (message);
		free (message);
		return -1;
	}

	/* save the last dir for cd -, if it's different */
	if ( strcmp(pwd, dir) )
		lastdir = pwd;
	return 1;
}

void builtin_clear ( void )
{
	printf ("\033[2J");
}

void builtin_pwd ( void )
{
	char *pwd = getcwd(NULL, 0);
	queue_message (pwd);
	xfree (pwd);
}