void
freejobs()
{
struct job *jp;
collectjobs(WNOHANG);
if (jobnote) {
int savefd = setb(2);
for (jp = joblst; jp; jp = jp->j_nxtp) {
if (jp->j_flag & J_NOTIFY) {
if (jp->j_jid)
printjob(jp, PR_DFL);
else if (jp->j_flag & J_FOREGND)
printjob(jp, PR_STAT);
else
printjob(jp, PR_STAT|PR_PGID);
}
}
(void) setb(savefd);
}
if (jobdone) {
for (jp = joblst; jp; jp = jp->j_nxtp) {
if (jp->j_flag & J_DONE)
freejob(jp);
}
}
}
recvjob()
{
struct stat stb;
char *bp = pbuf;
int status;
/*
* Perform lookup for printer name or abbreviation
*/
if ((status = pgetent(line, printer)) < 0)
fatal("cannot open printer description file");
else if (status == 0)
fatal("unknown printer");
if ((LF = pgetstr("lf", &bp)) == NULL)
LF = DEFLOGF;
if ((SD = pgetstr("sd", &bp)) == NULL)
SD = DEFSPOOL;
if ((LO = pgetstr("lo", &bp)) == NULL)
LO = DEFLOCK;
(void) close(2);
(void) open(LF, O_WRONLY|O_APPEND);
if (chdir(SD) < 0)
fatal("cannot chdir to %s", SD);
if (stat(LO, &stb) == 0 && (stb.st_mode & 010)) {
/* queue is disabled */
putchar('\1'); /* return error code */
exit(1);
}
if (readjob())
printjob();
}
/*
* 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)
{
char *argv[MAXARGS];
int isBG = parseline(cmdline, argv);
if (argv[0] == NULL) return;
if (builtin_cmd(argv)) return;
sigset_t allset;
sigfillset(&allset);
sigprocmask(SIG_BLOCK, &allset, NULL);
pid_t childpid = fork();
if (childpid == -1) unix_error("fork failed");
if (childpid == 0) {
sigprocmask(SIG_UNBLOCK, &allset, NULL);
if (setpgid(0, 0) == -1) unix_error("setpgrp failed");
if (execv(argv[0], argv) == -1) unix_error("execv failed");
}
if (isBG) {
addjob(jobs, childpid, BG, cmdline);
printjob(jobs, childpid);
sigprocmask(SIG_UNBLOCK, &allset, NULL);
} else {
addjob(jobs, childpid, FG, cmdline);
sigprocmask(SIG_UNBLOCK, &allset, NULL);
waitfg(childpid);
}
return;
}
/* listjobs - Print the job list */
void listjobs(struct job_t *jobs)
{
int i;
for (i = 0; i < MAXJOBS; i++) {
printjob(jobs, jobs[i].pid);
}
}
void
recvjob(void)
{
struct stat stb;
int status;
/*
* Perform lookup for printer name or abbreviation
*/
if ((status = cgetent(&bp, printcapdb, printer)) == -2)
frecverr("cannot open printer description file");
else if (status == -1)
frecverr("unknown printer %s", printer);
else if (status == -3)
fatal("potential reference loop detected in printcap file");
if (cgetstr(bp, "lf", &LF) == -1)
LF = _PATH_CONSOLE;
if (cgetstr(bp, "sd", &SD) == -1)
SD = _PATH_DEFSPOOL;
if (cgetstr(bp, "lo", &LO) == -1)
LO = DEFLOCK;
(void)close(2); /* set up log file */
PRIV_START;
if (open(LF, O_WRONLY|O_APPEND, 0664) < 0) {
syslog(LOG_ERR, "%s: %m", LF);
(void)open(_PATH_DEVNULL, O_WRONLY);
}
PRIV_END;
if (chdir(SD) < 0)
frecverr("%s: %s: %m", printer, SD);
if (stat(LO, &stb) == 0) {
if (stb.st_mode & 010) {
/* queue is disabled */
putchar('\1'); /* return error code */
exit(1);
}
} else if (stat(SD, &stb) < 0)
frecverr("%s: %s: %m", printer, SD);
minfree = 2 * read_number("minfree"); /* scale KB to 512 blocks */
signal(SIGTERM, rcleanup);
signal(SIGPIPE, rcleanup);
if (readjob())
printjob();
}
recvjob()
{
struct stat stb;
char *bp = pbuf;
int status, rcleanup();
/*
* Perform lookup for printer name or abbreviation
*/
if ((status = pgetent(line, printer)) < 0)
frecverr("cannot open printer description file");
else if (status == 0)
frecverr("unknown printer %s", printer);
if ((LF = pgetstr("lf", &bp)) == NULL)
LF = DEFLOGF;
if ((SD = pgetstr("sd", &bp)) == NULL)
SD = DEFSPOOL;
if ((LO = pgetstr("lo", &bp)) == NULL)
LO = DEFLOCK;
(void) close(2); /* set up log file */
if (open(LF, O_WRONLY|O_APPEND, 0664) < 0) {
syslog(LOG_ERR, "%s: %m", LF);
(void) open("/dev/null", O_WRONLY);
}
if (chdir(SD) < 0)
frecverr("%s: %s: %m", printer, SD);
if (stat(LO, &stb) == 0) {
if (stb.st_mode & 010) {
/* queue is disabled */
putchar('\1'); /* return error code */
exit(1);
}
} else if (stat(SD, &stb) < 0)
frecverr("%s: %s: %m", printer, SD);
minfree = read_number("minfree");
ddev = find_dev(stb.st_dev, S_IFBLK);
if ((dfd = open(ddev, O_RDONLY)) < 0)
syslog(LOG_WARNING, "%s: %s: %m", printer, ddev);
signal(SIGTERM, rcleanup);
signal(SIGPIPE, rcleanup);
if (readjob())
printjob();
}
void printallbanks()
{
printf("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@\n");
int num = 0;
jobqueue *j;
j = (jobqueue *)malloc(sizeof(jobqueue));
for(num; num<4; num++)
{
int jnum = row[num].jsize;
int a=0;
printf("-------------bank %d-----------\n", num);
{
int k = &row[num];
printf(" current rowbuffer : %s \n", row[num].rowbuffer);
printf(" current jobqueue size : %d \n ", row[num].jsize);
if(row[num].busy==1)
{
printf(" Row is busy \n");
}
else
{
printf(" Row is idle \n");
}
printf(" current job : \n");
j = row[num].rq;
for(a; a<jnum; a++)
{
printf(" %d job \n", a);
printjob(j);
printf("\n");
j = j->before;
}
}
}
printf("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@\n\n\n");
}
/*
* sigchld_handler - The kernel sends a SIGCHLD to the shell whenever
* a child job terminates (becomes a zombie), or stops because it
* received a SIGSTOP or SIGTSTP signal. The handler reaps all
* available zombie children, but doesn't wait for any other
* currently running children to terminate.
*/
void sigchld_handler(int sig)
{
for (;;) {
int status;
pid_t childpid = waitpid(-1, &status, WNOHANG | WUNTRACED | WCONTINUED);
if (childpid == -1) break; //unix_error("waitpid failed");
if (childpid == 0) break;
if (WIFEXITED(status)) {
deletejob(jobs, childpid);
// TODO: print exit code, WEXITSTATUS
} else if (WIFSIGNALED(status)){
deletejob(jobs, childpid);
printf("Job [1] (%d) terminated by signal %d\n", childpid, WTERMSIG(status));
} else if (WIFSTOPPED(status)) {
getjobpid(jobs, childpid)->state = ST;
printjob(jobs, childpid);
} else if (WIFCONTINUED(status)) {
int *state = &getjobpid(jobs, childpid)->state;
if (*state == ST) *state = BG;
}
}
return;
}
/*
* Make a pass through the printcap database and start printing any
* files left from the last time the machine went down.
*/
static void
startup(void)
{
int pid, status, more;
struct printer myprinter, *pp = &myprinter;
more = firstprinter(pp, &status);
if (status)
goto errloop;
while (more) {
if (ckqueue(pp) <= 0) {
goto next;
}
if (lflag)
syslog(LOG_INFO, "lpd startup: work for %s",
pp->printer);
if ((pid = fork()) < 0) {
syslog(LOG_WARNING, "lpd startup: cannot fork for %s",
pp->printer);
mcleanup(0);
}
if (pid == 0) {
lastprinter();
printjob(pp);
/* NOTREACHED */
}
do {
next:
more = nextprinter(pp, &status);
errloop:
if (status)
syslog(LOG_WARNING,
"lpd startup: printcap entry for %s has errors, skipping",
pp->printer ? pp->printer : "<noname?>");
} while (more && status);
}
}
int
main(void)
{
static char buf[100];
int fd;
//int status;
// Assumes three file descriptors open.
while((fd = open("console", O_RDWR)) >= 0){
if(fd >= 3){
close(fd);
break;
}
}
// Read and run input commands.
int jobcntr = 0;
jlist = malloc(sizeof(*jlist));
jlist->first = 0;
jlist->last = 0;
jlist->fgJob = 0;
int waitStatus;
int bPrintDollar = 1;
int cmdLen = 0;
while((cmdLen = getcmd(buf, sizeof(buf), bPrintDollar)) >= 0){
clearFinishedJobs(jlist);
// Check if there's a forground job running.
// If so - the shell should not function, but only transfer the data received from the console to the job's pipe
if (jlist->fgJob != 0) {
bPrintDollar = 0;
write(jlist->fgJob->fd, buf, cmdLen);
continue;
}
bPrintDollar = 1;
if(buf[0] == 'c' && buf[1] == 'd' && buf[2] == ' ') {
// Clumsy but will have to do for now.
// Chdir has no effect on the parent if run in the child.
buf[strlen(buf)-1] = 0; // chop \n
if(chdir(buf+3) < 0)
printf(2, "cannot cd %s\n", buf+3);
continue;
}
if(buf[0] == 'j' && buf[1] == 'o' && buf[2] == 'b' && buf[3] == 's' && (buf[4] == '\n' || buf[4] == ' ')) {
struct job* job = jlist->first;
while (job != 0) {
printjob(job->jid);
job = job->next;
}
if (!jlist->first)
printf(1, "There are no jobs.\n");
continue;
}
if(buf[0] == 'f' && buf[1] == 'g' && (buf[2] == '\n' || buf[2] == ' ')) {
char* c = &buf[3];
int jid = atoi(c);
struct job* j = jlist->first;
while ( j->jid != jid && j != 0) {
j = j->next;
}
jlist->fgJob = j;
//fg(jid);
continue;
}
// 0x0A - new line
if (buf[0] != 0x0A ) {
// create a pipe so the the shell sends the input to jobs_pipe[1] and the new process gets it in jobs_pipe[0]
if (pipe(jobs_pipe) == -1) {
panic("pipe");
}
struct job* job;
job = malloc(sizeof(*job));
memset(job, 0, sizeof(*job));
job->jid = ++jobcntr;
job->fd = jobs_pipe[1];
//char* s = job->cmd;
//char* t = buf;
//int i = sizeof(buf);
//while(--i > 0 && *t != '\n' && (*s++ = *t++) != 0) ;
//*s = 0;
struct cmd* command = parsecmd(buf);
int childPid = fork1();
if(childPid == 0) {
close(0);
dup(jobs_pipe[0]);
close(jobs_pipe[1]);
if(fork1() == 0)
runcmd(command);
exit(0);
}
close(jobs_pipe[0]); // The shell doesn't need the READ end.
attachjob(childPid, job); // Attach proc to job (Sys call)
// shell writes the input to job_buffer ONLY IF the cmd isn't a backgraound job
if (command->type != BACK) {
jlist->fgJob = job;
bPrintDollar = 0;
}
addJobToList(jlist, job);
wait(&waitStatus);
}
}
exit(0);
}
/*
* 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? */
int job_state; /* initial value of job BG or FG based on bg */
int status;
int check;
struct cmdline_tokens tok;
pid_t pid = -255; // Initialzing to
int jid = -255; // dummy values
sigset_t mask;
sigset_t mask2;
int flag = 0; //Used while processing "fg" built in command
int infile_fd ; //file descriptor to be used for infile if specified in job
int outfile_fd ; //file descriptor to be used for outfile if specified in job
//Get shell pid
tsh_pid = getpid();
//Intialize mask for blocked signal
//Block SIGCHLD SIGINT SIGTSTP signals
Sigemptyset(&mask);
Sigemptyset(&mask2);
Sigaddset(&mask,SIGCHLD);
Sigaddset(&mask,SIGINT);
Sigaddset(&mask2,SIGINT);
Sigaddset(&mask,SIGTSTP);
Sigaddset(&mask2,SIGTSTP);
Sigprocmask(SIG_BLOCK,&mask,NULL);
/* Parse command line */
bg = parseline(cmdline, &tok);
if (bg == -1) return; /* parsing error */
if (tok.argv[0] == NULL) return; /* ignore empty lines */
/* If tok is a BUILTIN shell command */
if (tok.builtins != BUILTIN_NONE) {
switch(tok.builtins) {
//Built in command quit :
//Send SIGKILL to all processes in shell
case BUILTIN_QUIT : tsh_pid = getpid();
kill(-tsh_pid,SIGKILL);
break;
//List out all jobs when "jobs" called
//Also open output file if redirection specified and
//redirect jobs output to the new file's descriptor
case BUILTIN_JOBS : if (tok.outfile != NULL) {
outfile_fd = open(tok.outfile , O_WRONLY);
listjobs(job_list,outfile_fd);
break;
}
else
listjobs(job_list,STDOUT_FILENO);
break;
// Parse job id or pid given with bg command
// Change state from ST to BG in job_list
// Send SIGCONT signal to job
case BUILTIN_FG : if(*(char *)(tok.argv[1]) == '%' ) {
jid = atoi( (((char *)(tok.argv[1])) + 1) );
pid = jid2pid(jid);
}
else {
pid = atoi(tok.argv[1]);
jid = pid2jid(pid);
}
change_job_state(job_list,pid,FG);
flag = 1; //flag set because we want to jump into else clause below
// to process resumed job as a foreground job
Kill(-pid,SIGCONT);
break;
//Parse job id or pid given with bg command
// Change state from ST to BG in job_list
// Send SIGCONT signal to job
case BUILTIN_BG : if(*(char *)(tok.argv[1]) == '%' ) {
jid = atoi( (((char *)(tok.argv[1])) + 1) );
pid = jid2pid(jid);
}
else {
pid = atoi(tok.argv[1]);
jid = pid2jid(pid);
}
printjob(pid,STDOUT_FILENO);
change_job_state(job_list,pid,BG);
Kill(-pid,SIGCONT);
break;
case BUILTIN_NONE : break;
default : break;
}
}
//If tok is a external program to be run by shell
else if ((tok.builtins == BUILTIN_NONE) || (flag == 1)) {
if (flag == 1)
bg = 0;
if(!bg)
job_state = FG;
else
job_state = BG;
//Child process
if ((pid = Fork()) == 0) {
setpgid(0,0); //Start process in new group
Signal(SIGINT, SIG_DFL); /* ctrl-c from child handled by parent's sigchld */
addjob(job_list,getpid(),job_state,cmdline);
// If input/output redirection specified open given file and point STDIN/STDOUT descriptor
// to new file's file descriptor
if (tok.infile != NULL) {
infile_fd = open(tok.infile , O_RDONLY);
dup2(infile_fd,STDIN_FILENO);
}
if (tok.outfile != NULL) {
outfile_fd = open(tok.outfile , O_WRONLY);
dup2(outfile_fd,STDOUT_FILENO);
}
//Unblock masks inherited from parent process
//and execute program using exec
Sigprocmask(SIG_UNBLOCK,&mask,NULL);
Execve(tok.argv[0],tok.argv,environ);
}
//Parent process
//Add child to job list and unblock signal,also set fg_pid if job is foreground job
addjob(job_list,pid,job_state,cmdline);
if(!bg)
fg_pid = pid;
Sigprocmask(SIG_UNBLOCK,&mask2,NULL);
//Until foreground process terminates SIGCHLD functionality is done here , SIGINT and SIGTSTP are handled by handlers
if(!bg) {
check = waitpid(pid,&status,WUNTRACED);
if ((check<0) && (errno!=ECHILD))
unix_error("waitfg : wait pid error\n");
if ((check == pid) && WIFSTOPPED(status)){
print_sigtstp_job(job_list,pid,SIGTSTP,STDOUT_FILENO); //Print message that job was stopped by SIGSTP signal
//Change stopped job state in list to ST (stopped)
change_job_state(job_list,pid,ST);
return;
}
if ((check == pid) && (WIFSIGNALED(status)))
print_sigint_job(job_list,pid,WTERMSIG(status),STDOUT_FILENO); //Print message that job/pid was terminated by a signal
deletejob(job_list,pid);
Sigprocmask(SIG_UNBLOCK,&mask,NULL);
}
else {
Sigprocmask(SIG_UNBLOCK,&mask,NULL);
printjob(pid,STDOUT_FILENO);
}
}
return;
}
