/* If dsh is running interactively as the foreground job
* then set the process group and signal handlers
* */
void init_dsh(){
// in batch mode, STDIN_FILENO is not associated to terminal input.
dsh_terminal_fd = STDIN_FILENO;
dsh_is_interactive = isatty(dsh_terminal_fd);
if(dsh_is_interactive) {
/* Loop until we are in the foreground. */
DEBUG("dsh run as foreground");
while(tcgetpgrp(dsh_terminal_fd) != (dsh_pgid = getpgrp())){
// SIGTTIN: (SIGnal due to TeleType INput)
kill(-dsh_pgid, SIGTTIN); /* Request for terminal input */
}
/* Ignore interactive and job-control signals.
* If tcsetpgrp() is called by a member of a background process
* group in its session, and the calling process is not blocking or
* ignoring SIGTTOU, a SIGTTOU signal is sent to all members of
* this background process group.
*/
// register signal handler. ignore all the
// SIGTTOU (SIGnal due to TeleType OUtput) is the corresponding signal when a backgrounded (nohuped, etc) job tries to output to the terminal.
signal(SIGTTOU, SIG_IGN);
dsh_pgid = getpid();
if(setpgid(dsh_pgid, dsh_pgid) < 0) {
perror("Couldn't put the dsh in its own process group");
exit(EXIT_FAILURE);
}
seize_tty(dsh_pgid);
printf("\n--- Hi, you are using dsh shell, have fun! ---\n\n");
}
else{
DEBUG("dsh run as background");
}
}
void init_dsh()
{
dsh_terminal_fd = STDIN_FILENO;
/* isatty(): test whether a file descriptor refers to a terminal
* isatty() returns 1 if fd is an open file descriptor referring to a
* terminal; otherwise 0 is returned, and errno is set to indicate the error.
* */
dsh_is_interactive = isatty(dsh_terminal_fd);
/* See if we are running interactively. */
if(dsh_is_interactive) {
/* Loop until we are in the foreground. */
while(tcgetpgrp(dsh_terminal_fd) != (dsh_pgid = getpgrp()))
kill(- dsh_pgid, SIGTTIN); /* Request for terminal input */
/* Ignore interactive and job-control signals.
* If tcsetpgrp() is called by a member of a background process
* group in its session, and the calling process is not blocking or
* ignoring SIGTTOU, a SIGTTOU signal is sent to all members of
* this background process group.
*/
signal(SIGTTOU, SIG_IGN);
/* Put the dsh in our own process group. */
dsh_pgid = getpid();
if(setpgid(dsh_pgid, dsh_pgid) < 0) {
perror("Couldn't put the dsh in its own process group");
exit(EXIT_FAILURE);
}
seize_tty(dsh_pgid);
}
}
/* Creates the context for a new child by setting the pid, pgid and tcsetpgrp */
void new_child(job_t *j, process_t *p, bool fg)
{
/* establish a new process group, and put the child in
* foreground if requested
*/
/* Put the process into the process group and give the process
* group the terminal, if appropriate. This has to be done both by
* the dsh and in the individual child processes because of
* potential race conditions.
* */
p->pid = getpid();
/* also establish child process group in child to avoid race (if parent has not done it yet). */
set_child_pgid(j, p);
if(fg) // if fg is set
seize_tty(j->pgid); // assign the terminal
/* Set the handling for job control signals back to the default. */
signal(SIGTTOU, SIG_DFL);
}
/*
* builtin_cmd - If the user has typed a built-in command then execute
* it immediately.
*/
bool builtin_cmd(job_t *last_job, int argc, char **argv)
{
/* check whether the cmd is a built in command
*/
if (!strcmp("quit", argv[0])) {
/* Your code here */
exit(EXIT_SUCCESS);
}
else if (!strcmp("jobs", argv[0])) {
/* Your code here */
job_t* currentJob = active_jobs_head;
job_t* deletedJob = NULL;
while(currentJob != NULL) {
// print active jobs and then change notified to 0
//if((currentJob->first_process)->completed == true && currentJob->notified == false) {
//need to check if every process has completed for a job to be complete, not just the first process
if (job_is_completed(currentJob) == true)
{
printf("%d (Completed): %s\n", currentJob->pgid, currentJob->commandinfo);
deletedJob = currentJob;
//currentJob->notified = true;
}
//otherwise it is stopped
else if (job_is_stopped(currentJob) == true)
{
printf("%d (Stopped): %s\n", currentJob->pgid, currentJob->commandinfo);
}
else
{
printf("%d (Running): %s\n", currentJob->pgid, currentJob->commandinfo);
}
currentJob = currentJob->next;
// delete job after it is completed, don't need to save notified
if (deletedJob != NULL)
{
if (deletedJob == active_jobs_head)
{
active_jobs_head = deletedJob->next;
free_job(deletedJob); //TBD warning about this?
}
else
{
delete_job(deletedJob, active_jobs_head);
}
deletedJob = NULL;
}
}
return true;
}
else if (!strcmp("cd", argv[0])) {
int chdir_return = chdir(argv[1]);
if(chdir_return == -1) {
printf("cd: %s: No such file or directory\n", argv[1]);
}
return true;
}
else if (!strcmp("bg", argv[0])) {
/* Your code here */
job_t* currentJob = active_jobs_head;
process_t* p2;
if(argv[1] == NULL)
{
// continue most recent stopped job
//use find_last_job
currentJob = find_last_job(active_jobs_head);
continue_job(currentJob);
seize_tty(currentJob->pgid);
p2 = currentJob->first_process;
while(p2 != NULL)
{
p2->stopped = false;
struct sigaction action;
action.sa_sigaction = sighandler;
sigfillset(&action.sa_mask);
action.sa_flags = SA_SIGINFO;
sigaction(SIGCHLD, &action, NULL);
p2 = p2->next;
}
seize_tty(getpid());
}
else
{
pid_t job_number = atoi(argv[1]);
while(currentJob != NULL) {
// Need to eventually iterate through all processes?
if((job_is_stopped(currentJob)) && currentJob->pgid == job_number) {
//seize_tty(currentJob->pgid);
continue_job(currentJob);
seize_tty(currentJob->pgid);
p2 = currentJob->first_process;
while (p2 != NULL)
{
p2->stopped = false;
struct sigaction action;
action.sa_sigaction = sighandler;
sigfillset(&action.sa_mask);
action.sa_flags = SA_SIGINFO;
sigaction(SIGCHLD, &action, NULL);
p2 = p2->next;
}
seize_tty(getpid());
break;
}
else if (currentJob->pgid == job_number) {
printf("%s\n", "This process wasn't stopped`");
}
else {
printf("%s\n", "This job number is not the requested one");
}
currentJob = currentJob->next;
}
}
return true;
}
else if (!strcmp("fg", argv[0])) {
/* Your code here */
job_t* currentJob = active_jobs_head;
process_t* p2;
if(argv[1] == NULL) {
// continue most recent stopped job
//use find_last_job
currentJob = find_last_job(active_jobs_head);
continue_job(currentJob);
seize_tty(currentJob->pgid);
p2 = currentJob->first_process;
while(p2 != NULL)
{
waiting(p2);
p2 = p2->next;
}
seize_tty(getpid());
}
else {
pid_t job_number = atoi(argv[1]);
while(currentJob != NULL) {
if((job_is_stopped(currentJob)) && currentJob->pgid == job_number) {
//seize_tty(currentJob->pgid);
continue_job(currentJob);
seize_tty(currentJob->pgid);
p2 = currentJob->first_process;
while (p2 != NULL)
{
waiting(p2);
p2 = p2->next;
}
seize_tty(getpid());
break;
}
else if (currentJob->pgid == job_number) {
printf("%s\n", "This process wasn't stopped`");
}
else {
printf("%s\n", "This job number is not the requested one");
}
currentJob = currentJob->next;
}
}
return true;
}
/* not a builtin command */
return false;
}
void spawn_job(job_t *j, bool fg)
{
pid_t pid;
process_t *p;
int countProcess = 0;
int loopCounter = -1;
int i;
//count number of processes in the job
for(p = j->first_process; p; p = p->next)
{
countProcess++;
}
//printf("count process: %d \n", countProcess);
int pipefd[countProcess-1][2]; //initialize 2-dimensional array [number of process][input/output]
//printf("test");
//open all pipes
if(countProcess > 1)
{
for(i = 0; i < (countProcess-1); i++)
{
//printf("piped %d \n", i);
pipe(pipefd[i]);
}
}
for(p = j->first_process; p; p = p->next) {
/* YOUR CODE HERE? */
/* Builtin commands are already taken care earlier */
loopCounter++;
switch (pid = fork()) {
// int status;
case -1: /* fork failure */
perror("fork");
exit(EXIT_FAILURE);
case 0: /* child process */
p->pid = getpid();
new_child(j, p, fg);
/* YOUR CODE HERE? Child-side code for new process. */
if (p->ifile != NULL)
{
int fd = open(p->ifile, O_RDONLY);
dup2(fd, STDIN_FILENO);
}
if (p->ofile != NULL)
{
int fd = open(p->ofile, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
dup2(fd, STDOUT_FILENO);
}
//pipe
if(countProcess > 1)
{
//printf("begin piping \n");
//first process is output
//need to loop through number of process and close all pipes
if(p == j->first_process)
{
dup2(pipefd[loopCounter][1], 1); //duplicate output as output for next process
closePipe(pipefd, countProcess);
}
//last process
else if (p->next == NULL)
{
dup2(pipefd[loopCounter-1][0], 0);
closePipe(pipefd, countProcess);
}
//for middle: dup both input and output
else
{
dup2(pipefd[loopCounter][1], 1);
dup2(pipefd[loopCounter-1][0], 0);
closePipe(pipefd, countProcess);
}
}
printf("%d (Launched): %s\n", j->pgid, j->commandinfo);
execvp(p->argv[0], p->argv);
perror("New child should have done an exec");
exit(EXIT_FAILURE); /* NOT REACHED */
break; /* NOT REACHED */
default: /* parent */
/* establish child process group */
p->pid = pid;
set_child_pgid(j, p);
/* YOUR CODE HERE? Parent-side code for new process. */
if (p->next == NULL) //if last process
{
process_t *p2;
p2 = j->first_process;
while(p2 != NULL)
{
//printf("waiting for process \n");
//if fg true waiting, else bg stuff
if(fg == true)
{
waiting(p2);
}
else
{
struct sigaction action;
action.sa_sigaction = sighandler;
sigfillset(&action.sa_mask);
action.sa_flags = SA_SIGINFO;
sigaction(SIGCHLD, &action, NULL);
}
closePipe(pipefd, countProcess);
p2 = p2->next;
}
}
//wait for child to finish
}
/* YOUR CODE HERE? Parent-side code for new job.*/
//printf("assign terminal back to dsh\n");
seize_tty(getpid()); // assign the terminal back to dsh
}
}
