void put_in_bg(job *jobs, int jid) {
if(jobs[jid].pid != 0) {
jobs[jid].state = BG;
kill(-jobs[jid].pid, SIGCONT);
wait_for_fg(jobs);
}
}
void builtincont(struct cmdline_tokens *tok, int state){
if (tok->argc < 2){
// app_error("Usage: %s [%jid/pid]\n", tok->argv[0]);
return;
}
pid_t pid;
/* JID */
if (tok->argv[1][0]=='%'){
int jid = atoi((char *)(tok->argv[1] + sizeof(char)));
pid = jid2pid(jid);
if (!pid)
app_error("No such jid \n");
}
else{
/* PID case */
pid = atoi(tok->argv[1]);
if (!pid2jid(pid))
app_error("No such pid \n");
}
/* Common to both JID & PID */
Kill(-pid, SIGCONT);
changestate(job_list, pid, state);
if (state==BG){
printf("[%d] (%d) %s\n", pid2jid(pid), pid,
getjobpid(job_list,pid)->cmdline);
}
if (state==FG){
wait_for_fg(pid);
}
}
void put_in_fg(job *jobs, int jid, int shell_terminal) {
if(jobs[jid].pid != 0) {
jobs[jid].state = FG;
tcsetpgrp(shell_terminal, jobs[jid].pid);
kill(-jobs[jid].pid, SIGCONT);
wait_for_fg(jobs);
tcsetpgrp(shell_terminal, getpid());
}
}
/*
* eval - Evaluate the command line that the user has just typed in
*
* If the user has requested a built-in command (quit, jobs, bg or fg)
* then execute it immediately. Otherwise, fork a child process and
* run the job in the context of the child. If the job is running in
* the foreground, wait for it to terminate and then return. Note:
* each child process must have a unique process group ID so that our
* background children don't receive SIGINT (SIGTSTP) from the kernel
* when we type ctrl-c (ctrl-z) at the keyboard.
*/
void
eval(char *cmdline)
{
int bg; /* should the job run in bg or fg? */
struct cmdline_tokens tok;
/* Parse command line */
bg = parseline(cmdline, &tok);
if (bg == -1) return; /* parsing error */
if (tok.argv[0] == NULL) return; /* ignore empty lines */
/* Built-in Command */
if (tok.builtins!=BUILTIN_NONE){
builtin_command(&tok);
return;
}
/* Common tasks for both foreground and background */
pid_t pid;
sigset_t mask;
Sigemptyset(&mask);
Sigaddset(&mask, SIGCHLD);
Sigaddset(&mask, SIGINT);
Sigaddset(&mask, SIGTSTP);
/* Block signal receving in parent */
Sigprocmask(SIG_BLOCK, &mask, NULL);
if ((pid=Fork())==0){
/* Unblock signal receiving in child */
Sigprocmask(SIG_UNBLOCK, &mask, NULL);
/* Changes the child's process group from the shell's */
Setpgid(0,0);
/* Change the input and output file descriptors */
IOredirection(&tok);
Execve(tok.argv[0], tok.argv, environ);
/* Command not found */
printf("Executable file not found\n");
exit(0);
}
/* Foreground job*/
if (!bg){
if (!addjob(job_list, pid, FG, cmdline))
return;
Sigprocmask(SIG_UNBLOCK, &mask, NULL);
wait_for_fg(pid);
return;
}
/* Background job */
if (bg){
if (!addjob(job_list, pid, BG, cmdline))
return;
Sigprocmask(SIG_UNBLOCK, &mask, NULL);
printf("[%d] (%d) %s\n", pid2jid(pid), pid, cmdline);
}
return;
}
