Adding upstream version 2.0.13.upstream/2.0.13upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1504 insertions, 0 deletions

diff --git a/usr/dash/jobs.c b/usr/dash/jobs.c
new file mode 100644
index 0000000..f027cc1
--- /dev/null
+++ b/usr/dash/jobs.c
@@ -0,0 +1,1504 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 1997-2005
+ *	Herbert Xu <herbert@gondor.apana.org.au>.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <fcntl.h>
+#include <signal.h>
+#include <unistd.h>
+#include <stdlib.h>
+#ifdef HAVE_PATHS_H
+#include <paths.h>
+#endif
+#include <sys/types.h>
+#include <sys/param.h>
+#ifdef BSD
+#include <sys/wait.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+#endif
+#include <sys/ioctl.h>
+
+#include "shell.h"
+#if JOBS
+#include <termios.h>
+#undef CEOF			/* syntax.h redefines this */
+#endif
+#include "redir.h"
+#include "show.h"
+#include "main.h"
+#include "parser.h"
+#include "nodes.h"
+#include "jobs.h"
+#include "options.h"
+#include "trap.h"
+#include "syntax.h"
+#include "input.h"
+#include "output.h"
+#include "memalloc.h"
+#include "error.h"
+#include "mystring.h"
+#include "system.h"
+
+/* mode flags for set_curjob */
+#define CUR_DELETE 2
+#define CUR_RUNNING 1
+#define CUR_STOPPED 0
+
+/* mode flags for dowait */
+#define DOWAIT_NORMAL 0
+#define DOWAIT_BLOCK 1
+#define DOWAIT_WAITCMD 2
+
+/* array of jobs */
+static struct job *jobtab;
+/* size of array */
+static unsigned njobs;
+/* pid of last background process */
+pid_t backgndpid;
+
+#if JOBS
+/* pgrp of shell on invocation */
+static int initialpgrp;
+/* control terminal */
+static int ttyfd = -1;
+#endif
+
+/* current job */
+static struct job *curjob;
+/* number of presumed living untracked jobs */
+static int jobless;
+
+STATIC void set_curjob(struct job *, unsigned);
+STATIC int jobno(const struct job *);
+STATIC int sprint_status(char *, int, int);
+STATIC void freejob(struct job *);
+STATIC struct job *getjob(const char *, int);
+STATIC struct job *growjobtab(void);
+STATIC void forkchild(struct job *, union node *, int);
+STATIC void forkparent(struct job *, union node *, int, pid_t);
+STATIC int dowait(int, struct job *);
+#ifdef SYSV
+STATIC int onsigchild(void);
+#endif
+STATIC int waitproc(int, int *);
+STATIC char *commandtext(union node *);
+STATIC void cmdtxt(union node *);
+STATIC void cmdlist(union node *, int);
+STATIC void cmdputs(const char *);
+STATIC void showpipe(struct job *, struct output *);
+STATIC int getstatus(struct job *);
+
+#if JOBS
+static int restartjob(struct job *, int);
+static void xtcsetpgrp(int, pid_t);
+#endif
+
+STATIC void
+set_curjob(struct job *jp, unsigned mode)
+{
+	struct job *jp1;
+	struct job **jpp, **curp;
+
+	/* first remove from list */
+	jpp = curp = &curjob;
+	do {
+		jp1 = *jpp;
+		if (jp1 == jp)
+			break;
+		jpp = &jp1->prev_job;
+	} while (1);
+	*jpp = jp1->prev_job;
+
+	/* Then re-insert in correct position */
+	jpp = curp;
+	switch (mode) {
+	default:
+#ifdef DEBUG
+		abort();
+#endif
+	case CUR_DELETE:
+		/* job being deleted */
+		break;
+	case CUR_RUNNING:
+		/* newly created job or backgrounded job,
+		   put after all stopped jobs. */
+		do {
+			jp1 = *jpp;
+			if (!JOBS || !jp1 || jp1->state != JOBSTOPPED)
+				break;
+			jpp = &jp1->prev_job;
+		} while (1);
+		/* FALLTHROUGH */
+#if JOBS
+	case CUR_STOPPED:
+#endif
+		/* newly stopped job - becomes curjob */
+		jp->prev_job = *jpp;
+		*jpp = jp;
+		break;
+	}
+}
+
+#if JOBS
+/*
+ * Turn job control on and off.
+ *
+ * Note:  This code assumes that the third arg to ioctl is a character
+ * pointer, which is true on Berkeley systems but not System V.  Since
+ * System V doesn't have job control yet, this isn't a problem now.
+ *
+ * Called with interrupts off.
+ */
+
+int jobctl;
+
+void
+setjobctl(int on)
+{
+	int fd;
+	int pgrp;
+
+	if (on == jobctl || rootshell == 0)
+		return;
+	if (on) {
+		int ofd;
+		ofd = fd = open(_PATH_TTY, O_RDWR);
+		if (fd < 0) {
+			fd += 3;
+			while (!isatty(fd))
+				if (--fd < 0)
+					goto out;
+		}
+		fd = savefd(fd, ofd);
+		do { /* while we are in the background */
+			if ((pgrp = tcgetpgrp(fd)) < 0) {
+out:
+				sh_warnx("can't access tty; job control turned off");
+				mflag = on = 0;
+				goto close;
+			}
+			if (pgrp == getpgrp())
+				break;
+			killpg(0, SIGTTIN);
+		} while (1);
+		initialpgrp = pgrp;
+
+		setsignal(SIGTSTP);
+		setsignal(SIGTTOU);
+		setsignal(SIGTTIN);
+		pgrp = rootpid;
+		setpgid(0, pgrp);
+		xtcsetpgrp(fd, pgrp);
+	} else {
+		/* turning job control off */
+		fd = ttyfd;
+		pgrp = initialpgrp;
+		xtcsetpgrp(fd, pgrp);
+		setpgid(0, pgrp);
+		setsignal(SIGTSTP);
+		setsignal(SIGTTOU);
+		setsignal(SIGTTIN);
+close:
+		close(fd);
+		fd = -1;
+	}
+	ttyfd = fd;
+	jobctl = on;
+}
+#endif
+
+
+int
+killcmd(argc, argv)
+	int argc;
+	char **argv;
+{
+	int signo = -1;
+	int list = 0;
+	int i;
+	pid_t pid;
+	struct job *jp;
+
+	if (argc <= 1) {
+usage:
+		sh_error(
+"Usage: kill [-s sigspec | -signum | -sigspec] [pid | job]... or\n"
+"kill -l [exitstatus]"
+		);
+	}
+
+	if (**++argv == '-') {
+		signo = decode_signal(*argv + 1, 1);
+		if (signo < 0) {
+			int c;
+
+			while ((c = nextopt("ls:")) != '\0')
+				switch (c) {
+				default:
+#ifdef DEBUG
+					abort();
+#endif
+				case 'l':
+					list = 1;
+					break;
+				case 's':
+					signo = decode_signal(optionarg, 1);
+					if (signo < 0) {
+						sh_error(
+							"invalid signal number or name: %s",
+							optionarg
+						);
+					}
+		                        break;
+				}
+			argv = argptr;
+		} else
+			argv++;
+	}
+
+	if (!list && signo < 0)
+		signo = SIGTERM;
+
+	if ((signo < 0 || !*argv) ^ list) {
+		goto usage;
+	}
+
+	if (list) {
+		struct output *out;
+
+		out = out1;
+		if (!*argv) {
+			outstr("0\n", out);
+			for (i = 1; i < NSIG; i++) {
+				outfmt(out, snlfmt, signal_name(i));
+			}
+			return 0;
+		}
+		signo = number(*argv);
+		if (signo > 128)
+			signo -= 128;
+		if (0 < signo && signo < NSIG)
+			outfmt(out, snlfmt, signal_name(signo));
+		else
+			sh_error("invalid signal number or exit status: %s",
+				 *argv);
+		return 0;
+	}
+
+	i = 0;
+	do {
+		if (**argv == '%') {
+			jp = getjob(*argv, 0);
+			pid = -jp->ps[0].pid;
+		} else
+			pid = **argv == '-' ?
+				-number(*argv + 1) : number(*argv);
+		if (kill(pid, signo) != 0) {
+			sh_warnx("%s\n", strerror(errno));
+			i = 1;
+		}
+	} while (*++argv);
+
+	return i;
+}
+
+STATIC int
+jobno(const struct job *jp)
+{
+	return jp - jobtab + 1;
+}
+
+#if JOBS
+int
+fgcmd(int argc, char **argv)
+{
+	struct job *jp;
+	struct output *out;
+	int mode;
+	int retval;
+
+	mode = (**argv == 'f') ? FORK_FG : FORK_BG;
+	nextopt(nullstr);
+	argv = argptr;
+	out = out1;
+	do {
+		jp = getjob(*argv, 1);
+		if (mode == FORK_BG) {
+			set_curjob(jp, CUR_RUNNING);
+			outfmt(out, "[%d] ", jobno(jp));
+		}
+		outstr(jp->ps->cmd, out);
+		showpipe(jp, out);
+		retval = restartjob(jp, mode);
+	} while (*argv && *++argv);
+	return retval;
+}
+
+int bgcmd(int argc, char **argv)
+#ifdef HAVE_ALIAS_ATTRIBUTE
+	__attribute__((__alias__("fgcmd")));
+#else
+{
+	return fgcmd(argc, argv);
+}
+#endif
+
+
+STATIC int
+restartjob(struct job *jp, int mode)
+{
+	struct procstat *ps;
+	int i;
+	int status;
+	pid_t pgid;
+
+	INTOFF;
+	if (jp->state == JOBDONE)
+		goto out;
+	jp->state = JOBRUNNING;
+	pgid = jp->ps->pid;
+	if (mode == FORK_FG)
+		xtcsetpgrp(ttyfd, pgid);
+	killpg(pgid, SIGCONT);
+	ps = jp->ps;
+	i = jp->nprocs;
+	do {
+		if (WIFSTOPPED(ps->status)) {
+			ps->status = -1;
+		}
+	} while (ps++, --i);
+out:
+	status = (mode == FORK_FG) ? waitforjob(jp) : 0;
+	INTON;
+	return status;
+}
+#endif
+
+STATIC int
+sprint_status(char *s, int status, int sigonly)
+{
+	int col;
+	int st;
+
+	col = 0;
+	st = WEXITSTATUS(status);
+	if (!WIFEXITED(status)) {
+#if JOBS
+		st = WSTOPSIG(status);
+		if (!WIFSTOPPED(status))
+#endif
+			st = WTERMSIG(status);
+		if (sigonly) {
+			if (st == SIGINT || st == SIGPIPE)
+				goto out;
+#if JOBS
+			if (WIFSTOPPED(status))
+				goto out;
+#endif
+		}
+		col = fmtstr(s, 32, "%s", strsignal(st));
+#ifdef WCOREDUMP
+		if (WCOREDUMP(status)) {
+			col += fmtstr(s + col, 16, " (core dumped)");
+		}
+#endif
+	} else if (!sigonly) {
+		if (st)
+			col = fmtstr(s, 16, "Done(%d)", st);
+		else
+			col = fmtstr(s, 16, "Done");
+	}
+
+out:
+	return col;
+}
+
+static void
+showjob(struct output *out, struct job *jp, int mode)
+{
+	struct procstat *ps;
+	struct procstat *psend;
+	int col;
+	int indent;
+	char s[80];
+
+	ps = jp->ps;
+
+	if (mode & SHOW_PGID) {
+		/* just output process (group) id of pipeline */
+		outfmt(out, "%d\n", ps->pid);
+		return;
+	}
+
+	col = fmtstr(s, 16, "[%d]   ", jobno(jp));
+	indent = col;
+
+	if (jp == curjob)
+		s[col - 2] = '+';
+	else if (curjob && jp == curjob->prev_job)
+		s[col - 2] = '-';
+
+	if (mode & SHOW_PID)
+		col += fmtstr(s + col, 16, "%d ", ps->pid);
+
+	psend = ps + jp->nprocs;
+
+	if (jp->state == JOBRUNNING) {
+		scopy("Running", s + col);
+		col += strlen("Running");
+	} else {
+		int status = psend[-1].status;
+#if JOBS
+		if (jp->state == JOBSTOPPED)
+			status = jp->stopstatus;
+#endif
+		col += sprint_status(s + col, status, 0);
+	}
+
+	goto start;
+
+	do {
+		/* for each process */
+		col = fmtstr(s, 48, " |\n%*c%d ", indent, ' ', ps->pid) - 3;
+
+start:
+		outfmt(
+			out, "%s%*c%s",
+			s, 33 - col >= 0 ? 33 - col : 0, ' ', ps->cmd
+		);
+		if (!(mode & SHOW_PID)) {
+			showpipe(jp, out);
+			break;
+		}
+		if (++ps == psend) {
+			outcslow('\n', out);
+			break;
+		}
+	} while (1);
+
+	jp->changed = 0;
+
+	if (jp->state == JOBDONE) {
+		TRACE(("showjob: freeing job %d\n", jobno(jp)));
+		freejob(jp);
+	}
+}
+
+
+int
+jobscmd(int argc, char **argv)
+{
+	int mode, m;
+	struct output *out;
+
+	mode = 0;
+	while ((m = nextopt("lp")))
+		if (m == 'l')
+			mode = SHOW_PID;
+		else
+			mode = SHOW_PGID;
+
+	out = out1;
+	argv = argptr;
+	if (*argv)
+		do
+			showjob(out, getjob(*argv,0), mode);
+		while (*++argv);
+	else
+		showjobs(out, mode);
+
+	return 0;
+}
+
+
+/*
+ * Print a list of jobs.  If "change" is nonzero, only print jobs whose
+ * statuses have changed since the last call to showjobs.
+ */
+
+void
+showjobs(struct output *out, int mode)
+{
+	struct job *jp;
+
+	TRACE(("showjobs(%x) called\n", mode));
+
+	/* If not even one one job changed, there is nothing to do */
+	while (dowait(DOWAIT_NORMAL, NULL) > 0)
+		continue;
+
+	for (jp = curjob; jp; jp = jp->prev_job) {
+		if (!(mode & SHOW_CHANGED) || jp->changed)
+			showjob(out, jp, mode);
+	}
+}
+
+/*
+ * Mark a job structure as unused.
+ */
+
+STATIC void
+freejob(struct job *jp)
+{
+	struct procstat *ps;
+	int i;
+
+	INTOFF;
+	for (i = jp->nprocs, ps = jp->ps ; --i >= 0 ; ps++) {
+		if (ps->cmd != nullstr)
+			ckfree(ps->cmd);
+	}
+	if (jp->ps != &jp->ps0)
+		ckfree(jp->ps);
+	jp->used = 0;
+	set_curjob(jp, CUR_DELETE);
+	INTON;
+}
+
+
+
+int
+waitcmd(int argc, char **argv)
+{
+	struct job *job;
+	int retval;
+	struct job *jp;
+
+	nextopt(nullstr);
+	retval = 0;
+
+	argv = argptr;
+	if (!*argv) {
+		/* wait for all jobs */
+		for (;;) {
+			jp = curjob;
+			while (1) {
+				if (!jp) {
+					/* no running procs */
+					goto out;
+				}
+				if (jp->state == JOBRUNNING)
+					break;
+				jp->waited = 1;
+				jp = jp->prev_job;
+			}
+			if (dowait(DOWAIT_WAITCMD, 0) <= 0)
+				goto sigout;
+		}
+	}
+
+	retval = 127;
+	do {
+		if (**argv != '%') {
+			pid_t pid = number(*argv);
+			job = curjob;
+			goto start;
+			do {
+				if (job->ps[job->nprocs - 1].pid == pid)
+					break;
+				job = job->prev_job;
+start:
+				if (!job)
+					goto repeat;
+			} while (1);
+		} else
+			job = getjob(*argv, 0);
+		/* loop until process terminated or stopped */
+		while (job->state == JOBRUNNING)
+			if (dowait(DOWAIT_WAITCMD, 0) <= 0)
+				goto sigout;
+		job->waited = 1;
+		retval = getstatus(job);
+repeat:
+		;
+	} while (*++argv);
+
+out:
+	return retval;
+
+sigout:
+	retval = 128 + pendingsigs;
+	goto out;
+}
+
+
+
+/*
+ * Convert a job name to a job structure.
+ */
+
+STATIC struct job *
+getjob(const char *name, int getctl)
+{
+	struct job *jp;
+	struct job *found;
+	const char *err_msg = "No such job: %s";
+	unsigned num;
+	int c;
+	const char *p;
+	char *(*match)(const char *, const char *);
+
+	jp = curjob;
+	p = name;
+	if (!p)
+		goto currentjob;
+
+	if (*p != '%')
+		goto err;
+
+	c = *++p;
+	if (!c)
+		goto currentjob;
+
+	if (!p[1]) {
+		if (c == '+' || c == '%') {
+currentjob:
+			err_msg = "No current job";
+			goto check;
+		} else if (c == '-') {
+			if (jp)
+				jp = jp->prev_job;
+			err_msg = "No previous job";
+check:
+			if (!jp)
+				goto err;
+			goto gotit;
+		}
+	}
+
+	if (is_number(p)) {
+		num = atoi(p);
+		if (num < njobs) {
+			jp = jobtab + num - 1;
+			if (jp->used)
+				goto gotit;
+			goto err;
+		}
+	}
+
+	match = prefix;
+	if (*p == '?') {
+		match = strstr;
+		p++;
+	}
+
+	found = 0;
+	while (1) {
+		if (!jp)
+			goto err;
+		if (match(jp->ps[0].cmd, p)) {
+			if (found)
+				goto err;
+			found = jp;
+			err_msg = "%s: ambiguous";
+		}
+		jp = jp->prev_job;
+	}
+
+gotit:
+#if JOBS
+	err_msg = "job %s not created under job control";
+	if (getctl && jp->jobctl == 0)
+		goto err;
+#endif
+	return jp;
+err:
+	sh_error(err_msg, name);
+}
+
+
+
+/*
+ * Return a new job structure.
+ * Called with interrupts off.
+ */
+
+struct job *
+makejob(union node *node, int nprocs)
+{
+	int i;
+	struct job *jp;
+
+	for (i = njobs, jp = jobtab ; ; jp++) {
+		if (--i < 0) {
+			jp = growjobtab();
+			break;
+		}
+		if (jp->used == 0)
+			break;
+		if (jp->state != JOBDONE || !jp->waited)
+			continue;
+		if (jobctl)
+			continue;
+		freejob(jp);
+		break;
+	}
+	memset(jp, 0, sizeof(*jp));
+#if JOBS
+	if (jobctl)
+		jp->jobctl = 1;
+#endif
+	jp->prev_job = curjob;
+	curjob = jp;
+	jp->used = 1;
+	jp->ps = &jp->ps0;
+	if (nprocs > 1) {
+		jp->ps = ckmalloc(nprocs * sizeof (struct procstat));
+	}
+	TRACE(("makejob(0x%lx, %d) returns %%%d\n", (long)node, nprocs,
+	    jobno(jp)));
+	return jp;
+}
+
+STATIC struct job *
+growjobtab(void)
+{
+	size_t len;
+	ptrdiff_t offset;
+	struct job *jp, *jq;
+
+	len = njobs * sizeof(*jp);
+	jq = jobtab;
+	jp = ckrealloc(jq, len + 4 * sizeof(*jp));
+
+	offset = (char *)jp - (char *)jq;
+	if (offset) {
+		/* Relocate pointers */
+		size_t l = len;
+
+		jq = (struct job *)((char *)jq + l);
+		while (l) {
+			l -= sizeof(*jp);
+			jq--;
+#define joff(p) ((struct job *)((char *)(p) + l))
+#define jmove(p) (p) = (void *)((char *)(p) + offset)
+			if (likely(joff(jp)->ps == &jq->ps0))
+				jmove(joff(jp)->ps);
+			if (joff(jp)->prev_job)
+				jmove(joff(jp)->prev_job);
+		}
+		if (curjob)
+			jmove(curjob);
+#undef joff
+#undef jmove
+	}
+
+	njobs += 4;
+	jobtab = jp;
+	jp = (struct job *)((char *)jp + len);
+	jq = jp + 3;
+	do {
+		jq->used = 0;
+	} while (--jq >= jp);
+	return jp;
+}
+
+
+/*
+ * Fork off a subshell.  If we are doing job control, give the subshell its
+ * own process group.  Jp is a job structure that the job is to be added to.
+ * N is the command that will be evaluated by the child.  Both jp and n may
+ * be NULL.  The mode parameter can be one of the following:
+ *	FORK_FG - Fork off a foreground process.
+ *	FORK_BG - Fork off a background process.
+ *	FORK_NOJOB - Like FORK_FG, but don't give the process its own
+ *		     process group even if job control is on.
+ *
+ * When job control is turned off, background processes have their standard
+ * input redirected to /dev/null (except for the second and later processes
+ * in a pipeline).
+ *
+ * Called with interrupts off.
+ */
+
+STATIC inline void
+forkchild(struct job *jp, union node *n, int mode)
+{
+	int oldlvl;
+
+	TRACE(("Child shell %d\n", getpid()));
+	oldlvl = shlvl;
+	shlvl++;
+
+	closescript();
+	clear_traps();
+#if JOBS
+	/* do job control only in root shell */
+	jobctl = 0;
+	if (mode != FORK_NOJOB && jp->jobctl && !oldlvl) {
+		pid_t pgrp;
+
+		if (jp->nprocs == 0)
+			pgrp = getpid();
+		else
+			pgrp = jp->ps[0].pid;
+		/* This can fail because we are doing it in the parent also */
+		(void)setpgid(0, pgrp);
+		if (mode == FORK_FG)
+			xtcsetpgrp(ttyfd, pgrp);
+		setsignal(SIGTSTP);
+		setsignal(SIGTTOU);
+	} else
+#endif
+	if (mode == FORK_BG) {
+		ignoresig(SIGINT);
+		ignoresig(SIGQUIT);
+		if (jp->nprocs == 0) {
+			close(0);
+			if (open(_PATH_DEVNULL, O_RDONLY) != 0)
+				sh_error("Can't open %s", _PATH_DEVNULL);
+		}
+	}
+	if (!oldlvl && iflag) {
+		setsignal(SIGINT);
+		setsignal(SIGQUIT);
+		setsignal(SIGTERM);
+	}
+	for (jp = curjob; jp; jp = jp->prev_job)
+		freejob(jp);
+	jobless = 0;
+}
+
+STATIC inline void
+forkparent(struct job *jp, union node *n, int mode, pid_t pid)
+{
+	TRACE(("In parent shell:  child = %d\n", pid));
+	if (!jp) {
+		while (jobless && dowait(DOWAIT_NORMAL, 0) > 0);
+		jobless++;
+		return;
+	}
+#if JOBS
+	if (mode != FORK_NOJOB && jp->jobctl) {
+		int pgrp;
+
+		if (jp->nprocs == 0)
+			pgrp = pid;
+		else
+			pgrp = jp->ps[0].pid;
+		/* This can fail because we are doing it in the child also */
+		(void)setpgid(pid, pgrp);
+	}
+#endif
+	if (mode == FORK_BG) {
+		backgndpid = pid;		/* set $! */
+		set_curjob(jp, CUR_RUNNING);
+	}
+	if (jp) {
+		struct procstat *ps = &jp->ps[jp->nprocs++];
+		ps->pid = pid;
+		ps->status = -1;
+		ps->cmd = nullstr;
+		if (jobctl && n)
+			ps->cmd = commandtext(n);
+	}
+}
+
+int
+forkshell(struct job *jp, union node *n, int mode)
+{
+	int pid;
+
+	TRACE(("forkshell(%%%d, %p, %d) called\n", jobno(jp), n, mode));
+	pid = fork();
+	if (pid < 0) {
+		TRACE(("Fork failed, errno=%d", errno));
+		if (jp)
+			freejob(jp);
+		sh_error("Cannot fork");
+	}
+	if (pid == 0)
+		forkchild(jp, n, mode);
+	else
+		forkparent(jp, n, mode, pid);
+	return pid;
+}
+
+/*
+ * Wait for job to finish.
+ *
+ * Under job control we have the problem that while a child process is
+ * running interrupts generated by the user are sent to the child but not
+ * to the shell.  This means that an infinite loop started by an inter-
+ * active user may be hard to kill.  With job control turned off, an
+ * interactive user may place an interactive program inside a loop.  If
+ * the interactive program catches interrupts, the user doesn't want
+ * these interrupts to also abort the loop.  The approach we take here
+ * is to have the shell ignore interrupt signals while waiting for a
+ * forground process to terminate, and then send itself an interrupt
+ * signal if the child process was terminated by an interrupt signal.
+ * Unfortunately, some programs want to do a bit of cleanup and then
+ * exit on interrupt; unless these processes terminate themselves by
+ * sending a signal to themselves (instead of calling exit) they will
+ * confuse this approach.
+ *
+ * Called with interrupts off.
+ */
+
+int
+waitforjob(struct job *jp)
+{
+	int st;
+
+	TRACE(("waitforjob(%%%d) called\n", jobno(jp)));
+	while (jp->state == JOBRUNNING) {
+		dowait(DOWAIT_BLOCK, jp);
+	}
+	st = getstatus(jp);
+#if JOBS
+	if (jp->jobctl) {
+		xtcsetpgrp(ttyfd, rootpid);
+		/*
+		 * This is truly gross.
+		 * If we're doing job control, then we did a TIOCSPGRP which
+		 * caused us (the shell) to no longer be in the controlling
+		 * session -- so we wouldn't have seen any ^C/SIGINT.  So, we
+		 * intuit from the subprocess exit status whether a SIGINT
+		 * occurred, and if so interrupt ourselves.  Yuck.  - mycroft
+		 */
+		if (jp->sigint)
+			raise(SIGINT);
+	}
+#endif
+	if (! JOBS || jp->state == JOBDONE)
+		freejob(jp);
+	return st;
+}
+
+
+
+/*
+ * Wait for a process to terminate.
+ */
+
+STATIC int
+dowait(int block, struct job *job)
+{
+	int pid;
+	int status;
+	struct job *jp;
+	struct job *thisjob = NULL;
+	int state;
+
+	INTOFF;
+	TRACE(("dowait(%d) called\n", block));
+	pid = waitproc(block, &status);
+	TRACE(("wait returns pid %d, status=%d\n", pid, status));
+	if (pid <= 0)
+		goto out;
+
+	for (jp = curjob; jp; jp = jp->prev_job) {
+		struct procstat *sp;
+		struct procstat *spend;
+		if (jp->state == JOBDONE)
+			continue;
+		state = JOBDONE;
+		spend = jp->ps + jp->nprocs;
+		sp = jp->ps;
+		do {
+			if (sp->pid == pid) {
+				TRACE(("Job %d: changing status of proc %d from 0x%x to 0x%x\n", jobno(jp), pid, sp->status, status));
+				sp->status = status;
+				thisjob = jp;
+			}
+			if (sp->status == -1)
+				state = JOBRUNNING;
+#if JOBS
+			if (state == JOBRUNNING)
+				continue;
+			if (WIFSTOPPED(sp->status)) {
+				jp->stopstatus = sp->status;
+				state = JOBSTOPPED;
+			}
+#endif
+		} while (++sp < spend);
+		if (thisjob)
+			goto gotjob;
+	}
+	if (!JOBS || !WIFSTOPPED(status))
+		jobless--;
+	goto out;
+
+gotjob:
+	if (state != JOBRUNNING) {
+		thisjob->changed = 1;
+
+		if (thisjob->state != state) {
+			TRACE(("Job %d: changing state from %d to %d\n", jobno(thisjob), thisjob->state, state));
+			thisjob->state = state;
+#if JOBS
+			if (state == JOBSTOPPED) {
+				set_curjob(thisjob, CUR_STOPPED);
+			}
+#endif
+		}
+	}
+
+out:
+	INTON;
+
+	if (thisjob && thisjob == job) {
+		char s[48 + 1];
+		int len;
+
+		len = sprint_status(s, status, 1);
+		if (len) {
+			s[len] = '\n';
+			s[len + 1] = 0;
+			outstr(s, out2);
+		}
+	}
+	return pid;
+}
+
+
+
+/*
+ * Do a wait system call.  If job control is compiled in, we accept
+ * stopped processes.  If block is zero, we return a value of zero
+ * rather than blocking.
+ *
+ * System V doesn't have a non-blocking wait system call.  It does
+ * have a SIGCLD signal that is sent to a process when one of it's
+ * children dies.  The obvious way to use SIGCLD would be to install
+ * a handler for SIGCLD which simply bumped a counter when a SIGCLD
+ * was received, and have waitproc bump another counter when it got
+ * the status of a process.  Waitproc would then know that a wait
+ * system call would not block if the two counters were different.
+ * This approach doesn't work because if a process has children that
+ * have not been waited for, System V will send it a SIGCLD when it
+ * installs a signal handler for SIGCLD.  What this means is that when
+ * a child exits, the shell will be sent SIGCLD signals continuously
+ * until is runs out of stack space, unless it does a wait call before
+ * restoring the signal handler.  The code below takes advantage of
+ * this (mis)feature by installing a signal handler for SIGCLD and
+ * then checking to see whether it was called.  If there are any
+ * children to be waited for, it will be.
+ *
+ * If neither SYSV nor BSD is defined, we don't implement nonblocking
+ * waits at all.  In this case, the user will not be informed when
+ * a background process until the next time she runs a real program
+ * (as opposed to running a builtin command or just typing return),
+ * and the jobs command may give out of date information.
+ */
+
+#ifdef SYSV
+STATIC int gotsigchild;
+
+STATIC int onsigchild() {
+	gotsigchild = 1;
+}
+#endif
+
+
+STATIC int
+waitproc(int block, int *status)
+{
+	sigset_t mask, oldmask;
+	int flags = block == DOWAIT_BLOCK ? 0 : WNOHANG;
+	int err;
+
+#if JOBS
+	if (jobctl)
+		flags |= WUNTRACED;
+#endif
+
+	do {
+		gotsigchld = 0;
+		err = wait3(status, flags, NULL);
+		if (err || !block)
+			break;
+
+		block = 0;
+
+		sigfillset(&mask);
+		sigprocmask(SIG_SETMASK, &mask, &oldmask);
+
+		while (!gotsigchld && !pendingsigs)
+			sigsuspend(&oldmask);
+
+		sigclearmask();
+	} while (gotsigchld);
+
+	return err;
+}
+
+/*
+ * return 1 if there are stopped jobs, otherwise 0
+ */
+int job_warning;
+int
+stoppedjobs(void)
+{
+	struct job *jp;
+	int retval;
+
+	retval = 0;
+	if (job_warning)
+		goto out;
+	jp = curjob;
+	if (jp && jp->state == JOBSTOPPED) {
+		out2str("You have stopped jobs.\n");
+		job_warning = 2;
+		retval++;
+	}
+
+out:
+	return retval;
+}
+
+/*
+ * Return a string identifying a command (to be printed by the
+ * jobs command).
+ */
+
+STATIC char *cmdnextc;
+
+STATIC char *
+commandtext(union node *n)
+{
+	char *name;
+
+	STARTSTACKSTR(cmdnextc);
+	cmdtxt(n);
+	name = stackblock();
+	TRACE(("commandtext: name %p, end %p\n", name, cmdnextc));
+	return savestr(name);
+}
+
+
+STATIC void
+cmdtxt(union node *n)
+{
+	union node *np;
+	struct nodelist *lp;
+	const char *p;
+	char s[2];
+
+	if (!n)
+		return;
+	switch (n->type) {
+	default:
+#if DEBUG
+		abort();
+#endif
+	case NPIPE:
+		lp = n->npipe.cmdlist;
+		for (;;) {
+			cmdtxt(lp->n);
+			lp = lp->next;
+			if (!lp)
+				break;
+			cmdputs(" | ");
+		}
+		break;
+	case NSEMI:
+		p = "; ";
+		goto binop;
+	case NAND:
+		p = " && ";
+		goto binop;
+	case NOR:
+		p = " || ";
+binop:
+		cmdtxt(n->nbinary.ch1);
+		cmdputs(p);
+		n = n->nbinary.ch2;
+		goto donode;
+	case NREDIR:
+	case NBACKGND:
+		n = n->nredir.n;
+		goto donode;
+	case NNOT:
+		cmdputs("!");
+		n = n->nnot.com;
+donode:
+		cmdtxt(n);
+		break;
+	case NIF:
+		cmdputs("if ");
+		cmdtxt(n->nif.test);
+		cmdputs("; then ");
+		if (n->nif.elsepart) {
+			cmdtxt(n->nif.ifpart);
+			cmdputs("; else ");
+			n = n->nif.elsepart;
+		} else {
+			n = n->nif.ifpart;
+		}
+		p = "; fi";
+		goto dotail;
+	case NSUBSHELL:
+		cmdputs("(");
+		n = n->nredir.n;
+		p = ")";
+		goto dotail;
+	case NWHILE:
+		p = "while ";
+		goto until;
+	case NUNTIL:
+		p = "until ";
+until:
+		cmdputs(p);
+		cmdtxt(n->nbinary.ch1);
+		n = n->nbinary.ch2;
+		p = "; done";
+dodo:
+		cmdputs("; do ");
+dotail:
+		cmdtxt(n);
+		goto dotail2;
+	case NFOR:
+		cmdputs("for ");
+		cmdputs(n->nfor.var);
+		cmdputs(" in ");
+		cmdlist(n->nfor.args, 1);
+		n = n->nfor.body;
+		p = "; done";
+		goto dodo;
+	case NDEFUN:
+		cmdputs(n->ndefun.text);
+		p = "() { ... }";
+		goto dotail2;
+	case NCMD:
+		cmdlist(n->ncmd.args, 1);
+		cmdlist(n->ncmd.redirect, 0);
+		break;
+	case NARG:
+		p = n->narg.text;
+dotail2:
+		cmdputs(p);
+		break;
+	case NHERE:
+	case NXHERE:
+		p = "<<...";
+		goto dotail2;
+	case NCASE:
+		cmdputs("case ");
+		cmdputs(n->ncase.expr->narg.text);
+		cmdputs(" in ");
+		for (np = n->ncase.cases; np; np = np->nclist.next) {
+			cmdtxt(np->nclist.pattern);
+			cmdputs(") ");
+			cmdtxt(np->nclist.body);
+			cmdputs(";; ");
+		}
+		p = "esac";
+		goto dotail2;
+	case NTO:
+		p = ">";
+		goto redir;
+	case NCLOBBER:
+		p = ">|";
+		goto redir;
+	case NAPPEND:
+		p = ">>";
+		goto redir;
+	case NTOFD:
+		p = ">&";
+		goto redir;
+	case NFROM:
+		p = "<";
+		goto redir;
+	case NFROMFD:
+		p = "<&";
+		goto redir;
+	case NFROMTO:
+		p = "<>";
+redir:
+		s[0] = n->nfile.fd + '0';
+		s[1] = '\0';
+		cmdputs(s);
+		cmdputs(p);
+		if (n->type == NTOFD || n->type == NFROMFD) {
+			s[0] = n->ndup.dupfd + '0';
+			p = s;
+			goto dotail2;
+		} else {
+			n = n->nfile.fname;
+			goto donode;
+		}
+	}
+}
+
+STATIC void
+cmdlist(union node *np, int sep)
+{
+	for (; np; np = np->narg.next) {
+		if (!sep)
+			cmdputs(spcstr);
+		cmdtxt(np);
+		if (sep && np->narg.next)
+			cmdputs(spcstr);
+	}
+}
+
+
+STATIC void
+cmdputs(const char *s)
+{
+	const char *p, *str;
+	char cc[2] = " ";
+	char *nextc;
+	signed char c;
+	int subtype = 0;
+	int quoted = 0;
+	static const char vstype[VSTYPE + 1][4] = {
+		"", "}", "-", "+", "?", "=",
+		"%", "%%", "#", "##",
+	};
+
+	nextc = makestrspace((strlen(s) + 1) * 8, cmdnextc);
+	p = s;
+	while ((c = *p++) != 0) {
+		str = 0;
+		switch (c) {
+		case CTLESC:
+			c = *p++;
+			break;
+		case CTLVAR:
+			subtype = *p++;
+			if ((subtype & VSTYPE) == VSLENGTH)
+				str = "${#";
+			else
+				str = "${";
+			goto dostr;
+		case CTLENDVAR:
+			str = "\"}";
+			str += !(quoted & 1);
+			quoted >>= 1;
+			subtype = 0;
+			goto dostr;
+		case CTLBACKQ:
+			str = "$(...)";
+			goto dostr;
+		case CTLARI:
+			str = "$((";
+			goto dostr;
+		case CTLENDARI:
+			str = "))";
+			goto dostr;
+		case CTLQUOTEMARK:
+			quoted ^= 1;
+			c = '"';
+			break;
+		case '=':
+			if (subtype == 0)
+				break;
+			if ((subtype & VSTYPE) != VSNORMAL)
+				quoted <<= 1;
+			str = vstype[subtype & VSTYPE];
+			if (subtype & VSNUL)
+				c = ':';
+			else
+				goto checkstr;
+			break;
+		case '\'':
+		case '\\':
+		case '"':
+		case '$':
+			/* These can only happen inside quotes */
+			cc[0] = c;
+			str = cc;
+			c = '\\';
+			break;
+		default:
+			break;
+		}
+		USTPUTC(c, nextc);
+checkstr:
+		if (!str)
+			continue;
+dostr:
+		while ((c = *str++)) {
+			USTPUTC(c, nextc);
+		}
+	}
+	if (quoted & 1) {
+		USTPUTC('"', nextc);
+	}
+	*nextc = 0;
+	cmdnextc = nextc;
+}
+
+
+STATIC void
+showpipe(struct job *jp, struct output *out)
+{
+	struct procstat *sp;
+	struct procstat *spend;
+
+	spend = jp->ps + jp->nprocs;
+	for (sp = jp->ps + 1; sp < spend; sp++)
+		outfmt(out, " | %s", sp->cmd);
+	outcslow('\n', out);
+	flushall();
+}
+
+
+#if JOBS
+STATIC void
+xtcsetpgrp(int fd, pid_t pgrp)
+{
+	if (tcsetpgrp(fd, pgrp))
+		sh_error("Cannot set tty process group (%s)", strerror(errno));
+}
+#endif
+
+
+STATIC int
+getstatus(struct job *job) {
+	int status;
+	int retval;
+
+	status = job->ps[job->nprocs - 1].status;
+	retval = WEXITSTATUS(status);
+	if (!WIFEXITED(status)) {
+#if JOBS
+		retval = WSTOPSIG(status);
+		if (!WIFSTOPPED(status))
+#endif
+		{
+			/* XXX: limits number of signals */
+			retval = WTERMSIG(status);
+#if JOBS
+			if (retval == SIGINT)
+				job->sigint = 1;
+#endif
+		}
+		retval += 128;
+	}
+	TRACE(("getstatus: job %d, nproc %d, status %x, retval %x\n",
+		jobno(job), job->nprocs, status, retval));
+	return retval;
+}