jobs.c

一个开放源代码的 AT&T 的 Korn Shell 的复制品, 支持大多数 ksh89 的特性。

				    (j->state == PEXITED) ? 0 : TF_MIPSKLUDGE);
				/* Don't use tty mode if job is stopped and
				 * later restarted and exits.  Consider
				 * the sequence:
				 *	vi foo (stopped)
				 *	...
				 *	stty something
				 *	...
				 *	fg (vi; ZZ)
				 * mode should be that of the stty, not what
				 * was before the vi started.
				 */
				if (j->state == PSTOPPED)
					j->flags &= ~JF_USETTYMODE;
			}
		}
#ifdef JOBS
		/* If it looks like user hit ^C to kill a job, pretend we got
		 * one too to break out of for loops, etc.  (at&t ksh does this
		 * even when not monitoring, but this doesn't make sense since
		 * a tty generated ^C goes to the whole process group)
		 */
		status = j->last_proc->status;
		if (Flag(FMONITOR) && j->state == PSIGNALLED
		    && WIFSIGNALED(status)
		    && (sigtraps[WTERMSIG(status)].flags & TF_TTY_INTR))
			trapsig(WTERMSIG(status));
#endif /* JOBS */
	}

	j_usrtime = j->usrtime;
	j_systime = j->systime;
	rv = j->status;

	if (!(flags & JW_ASYNCNOTIFY) 
	    && (!Flag(FMONITOR) || j->state != PSTOPPED))
	{
		j_print(j, JP_SHORT, shl_out);
		shf_flush(shl_out);
	}
	if (j->state != PSTOPPED
	    && (!Flag(FMONITOR) || !(flags & JW_ASYNCNOTIFY)))
		remove_job(j, where);

	return rv;
}

/* SIGCHLD handler to reap children and update job states
 *
 * If jobs are compiled in then this routine expects sigchld to be blocked.
 */
static RETSIGTYPE
j_sigchld(sig)
	int	sig;
{
	int		errno_ = errno;
	Job		*j;
	Proc		UNINITIALIZED(*p);
	int		pid;
	WAIT_T		status;
	struct tms	t0, t1;

#ifdef JOB_SIGS
	/* Don't wait for any processes if a job is partially started.
	 * This is so we don't do away with the process group leader
	 * before all the processes in a pipe line are started (so the
	 * setpgid() won't fail)
	 */
	for (j = job_list; j; j = j->next)
		if (j->ppid == procpid && !(j->flags & JF_STARTED)) {
			held_sigchld = 1;
			return RETSIGVAL;
		}
#endif /* JOB_SIGS */

	ksh_times(&t0);
	do {
#ifdef JOB_SIGS
		pid = ksh_waitpid(-1, &status, (WNOHANG|WUNTRACED));
#else /* JOB_SIGS */
		pid = wait(&status);
#endif /* JOB_SIGS */

		if (pid <= 0)	/* return if would block (0) ... */
			break;	/* ... or no children or interrupted (-1) */

		ksh_times(&t1);

		/* find job and process structures for this pid */
		for (j = job_list; j != (Job *) 0; j = j->next)
			for (p = j->proc_list; p != (Proc *) 0; p = p->next)
				if (p->pid == pid)
					goto found;
found:
		if (j == (Job *) 0) {
			/* Can occur if process has kids, then execs shell
			warningf(TRUE, "bad process waited for (pid = %d)",
				pid);
			 */
			t0 = t1;
			continue;
		}

		j->usrtime += t1.tms_cutime - t0.tms_cutime;
		j->systime += t1.tms_cstime - t0.tms_cstime;
		t0 = t1;
		p->status = status;
#ifdef JOBS
		if (WIFSTOPPED(status))
			p->state = PSTOPPED;
		else
#endif /* JOBS */
		if (WIFSIGNALED(status))
			p->state = PSIGNALLED;
		else
			p->state = PEXITED;

		check_job(j);	/* check to see if entire job is done */
	}
#ifdef JOB_SIGS
	while (1);
#else /* JOB_SIGS */
	while (0);
#endif /* JOB_SIGS */

	errno = errno_;

	return RETSIGVAL;
}

/*
 * Called only when a process in j has exited/stopped (ie, called only
 * from j_sigchld()).  If no processes are running, the job status
 * and state are updated, asynchronous job notification is done and,
 * if unneeded, the job is removed.
 *
 * If jobs are compiled in then this routine expects sigchld to be blocked.
 */
static void
check_job(j)
	Job	*j;
{
	int	jstate;
	Proc	*p;

	/* XXX debugging (nasty - interrupt routine using shl_out) */
	if (!(j->flags & JF_STARTED)) {
		internal_errorf(0, "check_job: job started (flags 0x%x)",
			j->flags);
		return;
	}

	jstate = PRUNNING;
	for (p=j->proc_list; p != (Proc *) 0; p = p->next) {
		if (p->state == PRUNNING)
			return;	/* some processes still running */
		if (p->state > jstate)
			jstate = p->state;
	}
	j->state = jstate;

	switch (j->last_proc->state) {
	case PEXITED:
		j->status = WEXITSTATUS(j->last_proc->status);
		break;
	case PSIGNALLED:
		j->status = 128 + WTERMSIG(j->last_proc->status);
		break;
	default:
		j->status = 0;
		break;
	}

#ifdef KSH
	/* Note when co-process dies: can't be done in j_wait() nor
	 * remove_job() since neither may be called for non-interactive 
	 * shells.
	 */
	if (j->state == PEXITED || j->state == PSIGNALLED) {
		/* No need to keep co-process input any more
		 * (at leasst, this is what ksh93d thinks)
		 */
		if (coproc.job == j) {
			coproc.job = (void *) 0;
			/* XXX would be nice to get the closes out of here
			 * so they aren't done in the signal handler.
			 * Would mean a check in coproc_getfd() to
			 * do "if job == 0 && write >= 0, close write".
			 */
			coproc_write_close(coproc.write);
		}
		/* Do we need to keep the output? */
		if (j->coproc_id && j->coproc_id == coproc.id
		    && --coproc.njobs == 0)
			coproc_readw_close(coproc.read);
	}
#endif /* KSH */

	j->flags |= JF_CHANGED;
#ifdef JOBS
	if (Flag(FMONITOR) && !(j->flags & JF_XXCOM)) {
		/* Only put stopped jobs at the front to avoid confusing
		 * the user (don't want finished jobs effecting %+ or %-)
		 */
		if (j->state == PSTOPPED)
			put_job(j, PJ_ON_FRONT);
		if (Flag(FNOTIFY)
		    && (j->flags & (JF_WAITING|JF_W_ASYNCNOTIFY)) != JF_WAITING)
		{
			/* Look for the real file descriptor 2 */
			{
				struct env *ep;
				int fd = 2;

				for (ep = e; ep; ep = ep->oenv)
					if (ep->savefd && ep->savefd[2])
						fd = ep->savefd[2];
				shf_reopen(fd, SHF_WR, shl_j);
			}
			/* Can't call j_notify() as it removes jobs.  The job
			 * must stay in the job list as j_waitj() may be
			 * running with this job.
			 */
			j_print(j, JP_MEDIUM, shl_j);
			shf_flush(shl_j);
			if (!(j->flags & JF_WAITING) && j->state != PSTOPPED)
				remove_job(j, "notify");
		}
	}
#endif /* JOBS */
	if (!Flag(FMONITOR) && !(j->flags & (JF_WAITING|JF_FG))
	    && j->state != PSTOPPED)
	{
		if (j == async_job || (j->flags & JF_KNOWN)) {
			j->flags |= JF_ZOMBIE;
			j->job = -1;
			nzombie++;
		} else
			remove_job(j, "checkjob");
	}
}

/*
 * Print job status in either short, medium or long format.
 *
 * If jobs are compiled in then this routine expects sigchld to be blocked.
 */
static void
j_print(j, how, shf)
	Job		*j;
	int		how;
	struct shf	*shf;
{
	Proc	*p;
	int	state;
	WAIT_T	status;
	int	coredumped;
	char	jobchar = ' ';
	char	buf[64];
	const char *filler;
	int	output = 0;

	if (how == JP_PGRP) {
		/* POSIX doesn't say what to do it there is no process
		 * group leader (ie, !FMONITOR).  We arbitrarily return
		 * last pid (which is what $! returns).
		 */
		shf_fprintf(shf, "%d\n", j->pgrp ? j->pgrp
				: (j->last_proc ? j->last_proc->pid : 0));
		return;
	}
	j->flags &= ~JF_CHANGED;
	filler = j->job > 10 ?  "\n       " : "\n      ";
	if (j == job_list)
		jobchar = '+';
	else if (j == job_list->next)
		jobchar = '-';

	for (p = j->proc_list; p != (Proc *) 0;) {
		coredumped = 0;
		switch (p->state) {
		case PRUNNING:
			strcpy(buf, "Running");
			break;
		case PSTOPPED:
			strcpy(buf, sigtraps[WSTOPSIG(p->status)].mess);
			break;
		case PEXITED:
			if (how == JP_SHORT)
				buf[0] = '\0';
			else if (WEXITSTATUS(p->status) == 0)
				strcpy(buf, "Done");
			else
				shf_snprintf(buf, sizeof(buf), "Done (%d)",
					WEXITSTATUS(p->status));
			break;
		case PSIGNALLED:
			if (WIFCORED(p->status))
				coredumped = 1;
			/* kludge for not reporting `normal termination signals'
			 * (ie, SIGINT, SIGPIPE)
			 */
			if (how == JP_SHORT && !coredumped
			    && (WTERMSIG(p->status) == SIGINT
				|| WTERMSIG(p->status) == SIGPIPE)) {
				buf[0] = '\0';
			} else
				strcpy(buf, sigtraps[WTERMSIG(p->status)].mess);
			break;
		}

		if (how != JP_SHORT)
			if (p == j->proc_list)
				shf_fprintf(shf, "[%d] %c ", j->job, jobchar);
			else
				shf_fprintf(shf, "%s", filler);

		if (how == JP_LONG)
			shf_fprintf(shf, "%5d ", p->pid);

		if (how == JP_SHORT) {
			if (buf[0]) {
				output = 1;
				shf_fprintf(shf, "%s%s ",
					buf, coredumped ? " (core dumped)" : null);
			}
		} else {
			output = 1;
			shf_fprintf(shf, "%-20s %s%s%s", buf, p->command,
				p->next ? "|" : null,
				coredumped ? " (core dumped)" : null);
		}

		state = p->state;
		status = p->status;
		p = p->next;
		while (p && p->state == state
		       && WSTATUS(p->status) == WSTATUS(status))
		{
			if (how == JP_LONG)
				shf_fprintf(shf, "%s%5d %-20s %s%s", filler, p->pid,
					space, p->command, p->next ? "|" : null);
			else if (how == JP_MEDIUM)
				shf_fprintf(shf, " %s%s", p->command,
					p->next ? "|" : null);
			p = p->next;
		}
	}
	if (output)
		shf_fprintf(shf, newline);
}

/* Convert % sequence to job
 *
 * If jobs are compiled in then this routine expects sigchld to be blocked.
 */
static Job *
j_lookup(cp, ecodep)
	const char *cp;
	int	*ecodep;
{
	Job		*j, *last_match;
	Proc		*p;
	int		len, job = 0;

	if (digit(*cp)) {
		job = atoi(cp);
		/* Look for last_proc->pid (what $! returns) first... */
		for (j = job_list; j != (Job *) 0; j = j->next)
			if (j->last_proc && j->last_proc->pid == job)
				return j;
		/* ...then look for process group (this is non-POSIX),
		 * but should not break anything (so FPOSIX isn't used).
		 */
		for (j = job_list; j != (Job *) 0; j = j->next)
			if (j->pgrp && j->pgrp == job)
				return j;
		if (ecodep)
			*ecodep = JL_NOSUCH;
		return (Job *) 0;
	}
	if (*cp != '%') {
		if (ecodep)
			*ecodep = JL_INVALID;
		return (Job *) 0;
	}
	switch (*++cp) {
	  case '\0': /* non-standard */
	  case '+':
	  case '%':
		if (job_list != (Job *) 0)
			return job_list;
		break;

	  case '-':
		if (job_list != (Job *) 0 && job_list->next)
			return job_list->next;
		break;

	  case '0': case '1': case '2': case '3': case '4':
	  case '5': case '6': case '7': case '8': case '9':
		job = atoi(cp);
		for (j = job_list; j != (Job *) 0; j = j->next)
			if (j->job == job)
				return j;
		break;

	  case '?':		/* %?string */
		last_match = (Job *) 0;
		for (j = job_list; j != (Job *) 0; j = j->next)
			for (p = j->proc_list; p != (Proc *) 0; p = p->next)
				if (strstr(p->command, cp+1) != (char *) 0) {
					if (last_match) {
						if (ecodep)
							*ecodep = JL_AMBIG;
						return (Job *) 0;
					}
					last_match = j;
				}
		if (last_match)
			return last_match;
		break;

	  default:		/* %string */
		len = strlen(cp);
		last_match = (Job *) 0;
		for (j = job_list; j != (Job *) 0; j = j->next)
			if (strncmp(cp, j->proc_list->command, len) == 0) {
				if (last_match) {
					if (ecodep)
						*ecodep = JL_AMBIG;
					return (Job *) 0;
				}
				last_match = j;
			}
		if (last_match)
			return last_match;
		break;
	}
	if (ecodep)
		*ecodep = JL_NOSUCH;
	return (Job *) 0;
}

static Job	*free_jobs;
static Proc	*free_procs;

/* allocate a new job and fill in the job number.
 *
 * If jobs are compiled in then this routine expects sigchld to be blocked.
 */
static Job *
new_job()
{
	int	i;
	Job	*newj, *j;

	if (free_jobs != (Job *) 0) {
		newj = free_jobs;
		free_jobs = free_jobs->next;
	} else
		newj = (Job *) alloc(sizeof(Job), APERM);

	/* brute force method */
	for (i = 1; ; i++) {
		for (j = job_list; j && j->job != i; j = j->next)
			;
		if (j == (Job *) 0)
			break;
	}
	newj->job = i;

	return newj;
}

/* Allocate new process strut
 *
 * If jobs are compiled in then this routine expects sigchld to be blocked.
 */
static Proc *
new_proc()
{
	Proc	*p;

	if (free_procs != (Proc *) 0) {
		p = free_procs;
		free_procs = free_procs->next;
	} else
		p = (Proc *) alloc(sizeof(Proc), APERM);

	return p;
}

/* Take job out of job_list and put old structures into free list.
 * Keeps nzombies, last_job and async_job up to date.
 *
 * If jobs are compiled in then this routine expects sigchld to be blocked.
 */
static void
remove_job(j, where)
	Job	*j;
	const char *where;
{
	Proc	*p, *tmp;
	Job	**prev, *curr;

	prev = &job_list;
	curr = *prev;
	for (; curr != (Job *) 0 && curr != j; prev = &curr->next, curr = *prev)
		;
	if (curr != j) {
		internal_errorf(0, "remove_job: job not found (%s)", where);
		return;
	}
	*prev = curr->next;

	/* free up proc structures */
	for (p = j->proc_list; p != (Proc *) 0; ) {
		tmp = p;
		p = p->next;
		tmp->next = free_procs;
		free_procs = tmp;
	}

	if ((j->flags & JF_ZOMBIE) && j->ppid == procpid)
		--nzombie;
	j->next = free_jobs;
	free_jobs = j;

	if (j == last_job)
		last_job = (Job *) 0;
	if (j == async_job)
		async_job = (Job *) 0;
}

/* put j in a particular location (taking it out job_list if it is there
 * already)
 *
 * If jobs are compiled in then this routine expects sigchld to be blocked.
 */
static void
put_job(j, where)
	Job	*j;
	int	where;
{
	Job	**prev, *curr;

	/* Remove job from list (if there) */
	prev = &job_list;
	curr = job_list;
	for (; curr && curr != j; prev = &curr->next, curr = *prev)
		;
	if (curr == j)
		*prev = curr->next;

	switch (where) {
	case PJ_ON_FRONT:
		j->next = job_list;
		job_list = j;
		break;

	case PJ_PAST_STOPPED:
		prev = &job_list;
		curr = job_list;
		for (; curr && curr->state == PSTOPPED; prev = &curr->next,
							curr = *prev)
			;
		j->next = curr;
		*prev = j;
		break;
	}
}

/* nuke a job (called when unable to start full job).
 *
 * If jobs are compiled in then this routine expects sigchld to be blocked.
 */
static void
kill_job(j)
	Job	*j;
{
	Proc	*p;

	for (p = j->proc_list; p != (Proc *) 0; p = p->next)
		if (p->pid != 0)
			(void) kill(p->pid, SIGKILL);
}

/* put a more useful name on a process than snptreef does (in certain cases) */
static void
fill_command(c, len, t)
	char		*c;
	int		len;
	struct op	*t;
{
	int		alen;
	char		**ap;

	if (t->type == TEXEC || t->type == TCOM) {
		/* Causes problems when set -u is in effect, can also
		   cause problems when array indices evaluated (may have
		   side effects, eg, assignment, incr, etc.)
		if (t->type == TCOM)
			ap = eval(t->args, DOBLANK|DONTRUNCOMMAND);
		else
		*/
		ap = t->args;
		--len; /* save room for the null */
		while (len > 0 && *ap != (char *) 0) {
			alen = strlen(*ap);
			if (alen > len)
				alen = len;
			memcpy(c, *ap, alen);
			c += alen;
			len -= alen;
			if (len > 0) {
				*c++ = ' '; len--;
			}
			ap++;
		}
		*c = '\0';
	} else
		snptreef(c, len, "%T", t);
}