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/trunk/uspace/app/ash/jobs.c
0,0 → 1,1263
/* $NetBSD: jobs.c,v 1.36 2000/05/22 10:18:47 elric Exp $ */
 
/*-
* Copyright (c) 1991, 1993
* The Regents of the University of California. 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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 <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)jobs.c 8.5 (Berkeley) 5/4/95";
#else
__RCSID("$NetBSD: jobs.c,v 1.36 2000/05/22 10:18:47 elric Exp $");
#endif
#endif /* not lint */
 
#include <fcntl.h>
#include <signal.h>
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>
#include <paths.h>
#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
#if OLD_TTY_DRIVER
#include "sgtty.h"
#else
#include <termios.h>
#endif
#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"
 
 
struct job *jobtab; /* array of jobs */
int njobs; /* size of array */
MKINIT short backgndpid = -1; /* pid of last background process */
#if JOBS
int initialpgrp; /* pgrp of shell on invocation */
short curjob; /* current job */
#endif
STATIC int intreceived;
 
STATIC void restartjob (struct job *);
STATIC void freejob (struct job *);
STATIC struct job *getjob (char *);
STATIC int dowait (int, struct job *);
STATIC int onsigchild (void);
STATIC int waitproc (int, int *);
STATIC void cmdtxt (union node *);
STATIC void cmdputs (const char *);
STATIC void waitonint(int);
 
 
#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.
*/
 
MKINIT int jobctl;
 
void
setjobctl(on)
int on;
{
#ifdef OLD_TTY_DRIVER
int ldisc;
#endif
 
if (on == jobctl || rootshell == 0)
return;
if (on) {
do { /* while we are in the background */
#ifdef OLD_TTY_DRIVER
if (ioctl(fd2, TIOCGPGRP, (char *)&initialpgrp) < 0) {
#else
initialpgrp = tcgetpgrp(fd2);
if (initialpgrp < 0) {
#endif
out2str("sh: can't access tty; job control turned off\n");
mflag = 0;
return;
}
if (initialpgrp == -1)
initialpgrp = getpgrp();
else if (initialpgrp != getpgrp()) {
killpg(initialpgrp, SIGTTIN);
continue;
}
} while (0);
#ifdef OLD_TTY_DRIVER
if (ioctl(fd2, TIOCGETD, (char *)&ldisc) < 0 || ldisc != NTTYDISC) {
out2str("sh: need new tty driver to run job control; job control turned off\n");
mflag = 0;
return;
}
#endif
setsignal(SIGTSTP);
setsignal(SIGTTOU);
setsignal(SIGTTIN);
setpgid(0, rootpid);
#ifdef OLD_TTY_DRIVER
ioctl(fd2, TIOCSPGRP, (char *)&rootpid);
#else
tcsetpgrp(fd2, rootpid);
#endif
} else { /* turning job control off */
setpgid(0, initialpgrp);
#ifdef OLD_TTY_DRIVER
ioctl(fd2, TIOCSPGRP, (char *)&initialpgrp);
#else
tcsetpgrp(fd2, initialpgrp);
#endif
setsignal(SIGTSTP);
setsignal(SIGTTOU);
setsignal(SIGTTIN);
}
jobctl = on;
}
#endif
 
 
#ifdef mkinit
INCLUDE <stdlib.h>
 
SHELLPROC {
backgndpid = -1;
#if JOBS
jobctl = 0;
#endif
}
 
#endif
 
 
 
#if JOBS
int
killcmd(argc, argv)
int argc;
char **argv;
{
extern char *signal_names[];
int signo = -1;
int list = 0;
int i;
pid_t pid;
struct job *jp;
 
if (argc <= 1) {
error(
"Usage: kill [-s sigspec | -signum | -sigspec] [pid | job]... or\n"
"kill -l [exitstatus]"
);
}
 
if (*argv[1] == '-') {
signo = decode_signal(argv[1]+1);
if (signo < 0) {
int c;
 
while ((c = nextopt("ls:")) != '\0')
switch (c) {
case 'l':
list = 1;
break;
case 's':
signo = decode_signal(optarg);
break;
default:
error(
"nextopt returned character code 0%o", c);
}
} else
argptr++;
}
 
if (!list && signo < 0)
signo = SIGTERM;
 
if ((signo < 0 || !*argptr) ^ list) {
error(
"Usage: kill [-s sigspec | -signum | -sigspec] [pid | job]... or\n"
"kill -l [exitstatus]"
);
}
 
if (list) {
if (!*argptr) {
out1fmt("0\n");
for (i = 1; i < NSIG; i++) {
if (strncmp(signal_names[i], "SIGJUNK(", 8)
== 0)
continue;
out1fmt("%s\n", signal_names[i] + 3);
}
return 0;
}
signo = atoi(*argptr);
if (signo > 128)
signo -= 128;
if (0 < signo && signo < NSIG)
out1fmt("%s\n", signal_names[signo] + 3);
else
error("invalid signal number or exit status: %s",
*argptr);
return 0;
}
 
do {
if (**argptr == '%') {
jp = getjob(*argptr);
if (jp->jobctl == 0)
error("job %s not created under job control",
*argptr);
pid = -jp->ps[0].pid;
} else
pid = atoi(*argptr);
if (kill(pid, signo) != 0)
error("%s: %s", *argptr, strerror(errno));
} while (*++argptr);
 
return 0;
}
 
int
fgcmd(argc, argv)
int argc;
char **argv;
{
struct job *jp;
int pgrp;
int status;
 
jp = getjob(argv[1]);
if (jp->jobctl == 0)
error("job not created under job control");
pgrp = jp->ps[0].pid;
#ifdef OLD_TTY_DRIVER
ioctl(fd2, TIOCSPGRP, (char *)&pgrp);
#else
tcsetpgrp(fd2, pgrp);
#endif
restartjob(jp);
INTOFF;
status = waitforjob(jp);
INTON;
return status;
}
 
 
int
bgcmd(argc, argv)
int argc;
char **argv;
{
struct job *jp;
 
do {
jp = getjob(*++argv);
if (jp->jobctl == 0)
error("job not created under job control");
restartjob(jp);
} while (--argc > 1);
return 0;
}
 
 
STATIC void
restartjob(jp)
struct job *jp;
{
struct procstat *ps;
int i;
 
if (jp->state == JOBDONE)
return;
INTOFF;
killpg(jp->ps[0].pid, SIGCONT);
for (ps = jp->ps, i = jp->nprocs ; --i >= 0 ; ps++) {
if (WIFSTOPPED(ps->status)) {
ps->status = -1;
jp->state = 0;
}
}
INTON;
}
#endif
 
 
int
jobscmd(argc, argv)
int argc;
char **argv;
{
showjobs(0);
return 0;
}
 
 
/*
* Print a list of jobs. If "change" is nonzero, only print jobs whose
* statuses have changed since the last call to showjobs.
*
* If the shell is interrupted in the process of creating a job, the
* result may be a job structure containing zero processes. Such structures
* will be freed here.
*/
 
void
showjobs(change)
int change;
{
int jobno;
int procno;
int i;
struct job *jp;
struct procstat *ps;
int col;
char s[64];
 
TRACE(("showjobs(%d) called\n", change));
while (dowait(0, (struct job *)NULL) > 0);
for (jobno = 1, jp = jobtab ; jobno <= njobs ; jobno++, jp++) {
if (! jp->used)
continue;
if (jp->nprocs == 0) {
freejob(jp);
continue;
}
if (change && ! jp->changed)
continue;
procno = jp->nprocs;
for (ps = jp->ps ; ; ps++) { /* for each process */
if (ps == jp->ps)
fmtstr(s, 64, "[%d] %ld ", jobno,
(long)ps->pid);
else
fmtstr(s, 64, " %ld ",
(long)ps->pid);
out1str(s);
col = strlen(s);
s[0] = '\0';
if (ps->status == -1) {
/* don't print anything */
} else if (WIFEXITED(ps->status)) {
fmtstr(s, 64, "Exit %d",
WEXITSTATUS(ps->status));
} else {
#if JOBS
if (WIFSTOPPED(ps->status))
i = WSTOPSIG(ps->status);
else /* WIFSIGNALED(ps->status) */
#endif
i = WTERMSIG(ps->status);
if ((i & 0x7F) < NSIG && sys_siglist[i & 0x7F])
scopy(sys_siglist[i & 0x7F], s);
else
fmtstr(s, 64, "Signal %d", i & 0x7F);
if (WCOREDUMP(ps->status))
strcat(s, " (core dumped)");
}
out1str(s);
col += strlen(s);
do {
out1c(' ');
col++;
} while (col < 30);
out1str(ps->cmd);
out1c('\n');
if (--procno <= 0)
break;
}
jp->changed = 0;
if (jp->state == JOBDONE) {
freejob(jp);
}
}
}
 
 
/*
* Mark a job structure as unused.
*/
 
STATIC void
freejob(jp)
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;
#if JOBS
if (curjob == jp - jobtab + 1)
curjob = 0;
#endif
INTON;
}
 
 
 
int
waitcmd(argc, argv)
int argc;
char **argv;
{
struct job *job;
int status, retval;
struct job *jp;
 
if (argc > 1) {
job = getjob(argv[1]);
} else {
job = NULL;
}
for (;;) { /* loop until process terminated or stopped */
if (job != NULL) {
if (job->state) {
status = job->ps[job->nprocs - 1].status;
if (WIFEXITED(status))
retval = WEXITSTATUS(status);
#if JOBS
else if (WIFSTOPPED(status))
retval = WSTOPSIG(status) + 128;
#endif
else {
/* XXX: limits number of signals */
retval = WTERMSIG(status) + 128;
}
if (! iflag)
freejob(job);
return retval;
}
} else {
for (jp = jobtab ; ; jp++) {
if (jp >= jobtab + njobs) { /* no running procs */
return 0;
}
if (jp->used && jp->state == 0)
break;
}
}
dowait(1, (struct job *)NULL);
}
}
 
 
 
int
jobidcmd(argc, argv)
int argc;
char **argv;
{
struct job *jp;
int i;
 
jp = getjob(argv[1]);
for (i = 0 ; i < jp->nprocs ; ) {
out1fmt("%ld", (long)jp->ps[i].pid);
out1c(++i < jp->nprocs? ' ' : '\n');
}
return 0;
}
 
 
 
/*
* Convert a job name to a job structure.
*/
 
STATIC struct job *
getjob(name)
char *name;
{
int jobno;
struct job *jp;
int pid;
int i;
 
if (name == NULL) {
#if JOBS
currentjob:
if ((jobno = curjob) == 0 || jobtab[jobno - 1].used == 0)
error("No current job");
return &jobtab[jobno - 1];
#else
error("No current job");
#endif
} else if (name[0] == '%') {
if (is_digit(name[1])) {
jobno = number(name + 1);
if (jobno > 0 && jobno <= njobs
&& jobtab[jobno - 1].used != 0)
return &jobtab[jobno - 1];
#if JOBS
} else if (name[1] == '%' && name[2] == '\0') {
goto currentjob;
#endif
} else {
struct job *found = NULL;
for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
if (jp->used && jp->nprocs > 0
&& prefix(name + 1, jp->ps[0].cmd)) {
if (found)
error("%s: ambiguous", name);
found = jp;
}
}
if (found)
return found;
}
} else if (is_number(name)) {
pid = number(name);
for (jp = jobtab, i = njobs ; --i >= 0 ; jp++) {
if (jp->used && jp->nprocs > 0
&& jp->ps[jp->nprocs - 1].pid == pid)
return jp;
}
}
error("No such job: %s", name);
/* NOTREACHED */
}
 
 
 
/*
* Return a new job structure,
*/
 
struct job *
makejob(node, nprocs)
union node *node;
int nprocs;
{
int i;
struct job *jp;
 
for (i = njobs, jp = jobtab ; ; jp++) {
if (--i < 0) {
INTOFF;
if (njobs == 0) {
jobtab = ckmalloc(4 * sizeof jobtab[0]);
} else {
jp = ckmalloc((njobs + 4) * sizeof jobtab[0]);
memcpy(jp, jobtab, njobs * sizeof jp[0]);
/* Relocate `ps' pointers */
for (i = 0; i < njobs; i++)
if (jp[i].ps == &jobtab[i].ps0)
jp[i].ps = &jp[i].ps0;
ckfree(jobtab);
jobtab = jp;
}
jp = jobtab + njobs;
for (i = 4 ; --i >= 0 ; jobtab[njobs++].used = 0);
INTON;
break;
}
if (jp->used == 0)
break;
}
INTOFF;
jp->state = 0;
jp->used = 1;
jp->changed = 0;
jp->nprocs = 0;
#if JOBS
jp->jobctl = jobctl;
#endif
if (nprocs > 1) {
jp->ps = ckmalloc(nprocs * sizeof (struct procstat));
} else {
jp->ps = &jp->ps0;
}
INTON;
TRACE(("makejob(0x%lx, %d) returns %%%d\n", (long)node, nprocs,
jp - jobtab + 1));
return jp;
}
 
 
/*
* Fork of 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).
*/
 
int
forkshell(jp, n, mode)
union node *n;
struct job *jp;
int mode;
{
int pid;
int pgrp;
const char *devnull = _PATH_DEVNULL;
const char *nullerr = "Can't open %s";
 
TRACE(("forkshell(%%%d, 0x%lx, %d) called\n", jp - jobtab, (long)n,
mode));
INTOFF;
pid = fork();
if (pid == -1) {
TRACE(("Fork failed, errno=%d\n", errno));
INTON;
error("Cannot fork");
}
if (pid == 0) {
struct job *p;
int wasroot;
int i;
 
TRACE(("Child shell %d\n", getpid()));
wasroot = rootshell;
rootshell = 0;
closescript();
INTON;
clear_traps();
#if JOBS
jobctl = 0; /* do job control only in root shell */
if (wasroot && mode != FORK_NOJOB && mflag) {
if (jp == NULL || jp->nprocs == 0)
pgrp = getpid();
else
pgrp = jp->ps[0].pid;
setpgid(0, pgrp);
if (mode == FORK_FG) {
/*** this causes superfluous TIOCSPGRPS ***/
#ifdef OLD_TTY_DRIVER
if (ioctl(fd2, TIOCSPGRP, (char *)&pgrp) < 0)
error("TIOCSPGRP failed, errno=%d", errno);
#else
if (tcsetpgrp(fd2, pgrp) < 0)
error("tcsetpgrp failed, errno=%d", errno);
#endif
}
setsignal(SIGTSTP);
setsignal(SIGTTOU);
} else if (mode == FORK_BG) {
ignoresig(SIGINT);
ignoresig(SIGQUIT);
ignoresig(SIGHUP);
if ((jp == NULL || jp->nprocs == 0) &&
! fd0_redirected_p ()) {
close(0);
if (open(devnull, O_RDONLY) != 0)
error(nullerr, devnull);
}
}
#else
if (mode == FORK_BG) {
ignoresig(SIGINT);
ignoresig(SIGQUIT);
ignoresig(SIGHUP);
if ((jp == NULL || jp->nprocs == 0) &&
! fd0_redirected_p ()) {
close(0);
if (open(devnull, O_RDONLY) != 0)
error(nullerr, devnull);
}
}
#endif
for (i = njobs, p = jobtab ; --i >= 0 ; p++)
if (p->used)
freejob(p);
if (wasroot && iflag) {
setsignal(SIGINT);
setsignal(SIGQUIT);
setsignal(SIGTERM);
}
return pid;
}
if (rootshell && mode != FORK_NOJOB && mflag) {
if (jp == NULL || jp->nprocs == 0)
pgrp = pid;
else
pgrp = jp->ps[0].pid;
setpgid(pid, pgrp);
}
if (mode == FORK_BG)
backgndpid = pid; /* set $! */
if (jp) {
struct procstat *ps = &jp->ps[jp->nprocs++];
ps->pid = pid;
ps->status = -1;
ps->cmd = nullstr;
if (iflag && rootshell && n)
ps->cmd = commandtext(n);
}
INTON;
TRACE(("In parent shell: child = %d\n", 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.
*/
 
int
waitforjob(jp)
struct job *jp;
{
#if JOBS
int mypgrp = getpgrp();
#endif
int status;
int st;
struct sigaction act, oact;
 
INTOFF;
intreceived = 0;
#if JOBS
if (!jobctl) {
#else
if (!iflag) {
#endif
sigaction(SIGINT, 0, &act);
act.sa_handler = waitonint;
sigaction(SIGINT, &act, &oact);
}
TRACE(("waitforjob(%%%d) called\n", jp - jobtab + 1));
while (jp->state == 0) {
dowait(1, jp);
}
#if JOBS
if (!jobctl) {
#else
if (!iflag) {
#endif
extern char *trap[];
sigaction(SIGINT, &oact, 0);
if (intreceived && trap[SIGINT]) kill(getpid(), SIGINT);
}
#if JOBS
if (jp->jobctl) {
#ifdef OLD_TTY_DRIVER
if (ioctl(fd2, TIOCSPGRP, (char *)&mypgrp) < 0)
error("TIOCSPGRP failed, errno=%d\n", errno);
#else
if (tcsetpgrp(fd2, mypgrp) < 0)
error("tcsetpgrp failed, errno=%d\n", errno);
#endif
}
if (jp->state == JOBSTOPPED)
curjob = jp - jobtab + 1;
#endif
status = jp->ps[jp->nprocs - 1].status;
/* convert to 8 bits */
if (WIFEXITED(status))
st = WEXITSTATUS(status);
#if JOBS
else if (WIFSTOPPED(status))
st = WSTOPSIG(status) + 128;
#endif
else
st = WTERMSIG(status) + 128;
#if JOBS
if (jp->jobctl) {
/*
* 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
* occured, and if so interrupt ourselves. Yuck. - mycroft
*/
if (WIFSIGNALED(status) && WTERMSIG(status) == SIGINT)
raise(SIGINT);
}
#endif
if (! JOBS || jp->state == JOBDONE)
freejob(jp);
INTON;
return st;
}
 
 
 
/*
* Wait for a process to terminate.
*/
 
STATIC int
dowait(block, job)
int block;
struct job *job;
{
int pid;
int status;
struct procstat *sp;
struct job *jp;
struct job *thisjob;
int done;
int stopped;
int core;
int sig;
 
TRACE(("dowait(%d) called\n", block));
do {
pid = waitproc(block, &status);
TRACE(("wait returns %d, status=%d\n", pid, status));
} while (pid == -1 && errno == EINTR);
if (pid <= 0)
return pid;
INTOFF;
thisjob = NULL;
for (jp = jobtab ; jp < jobtab + njobs ; jp++) {
if (jp->used) {
done = 1;
stopped = 1;
for (sp = jp->ps ; sp < jp->ps + jp->nprocs ; sp++) {
if (sp->pid == -1)
continue;
if (sp->pid == pid) {
TRACE(("Changing status of proc %d from 0x%x to 0x%x\n", pid, sp->status, status));
sp->status = status;
thisjob = jp;
}
if (sp->status == -1)
stopped = 0;
else if (WIFSTOPPED(sp->status))
done = 0;
}
if (stopped) { /* stopped or done */
int state = done? JOBDONE : JOBSTOPPED;
if (jp->state != state) {
TRACE(("Job %d: changing state from %d to %d\n", jp - jobtab + 1, jp->state, state));
jp->state = state;
#if JOBS
if (done && curjob == jp - jobtab + 1)
curjob = 0; /* no current job */
#endif
}
}
}
}
INTON;
if (! rootshell || ! iflag || (job && thisjob == job)) {
core = WCOREDUMP(status);
#if JOBS
if (WIFSTOPPED(status)) sig = WSTOPSIG(status);
else
#endif
if (WIFEXITED(status)) sig = 0;
else sig = WTERMSIG(status);
 
if (sig != 0 && sig != SIGINT && sig != SIGPIPE) {
if (thisjob != job)
outfmt(out2, "%d: ", pid);
#if JOBS
if (sig == SIGTSTP && rootshell && iflag)
outfmt(out2, "%%%ld ",
(long)(job - jobtab + 1));
#endif
if (sig < NSIG && sys_siglist[sig])
out2str(sys_siglist[sig]);
else
outfmt(out2, "Signal %d", sig);
if (core)
out2str(" - core dumped");
out2c('\n');
flushout(&errout);
} else {
TRACE(("Not printing status: status=%d, sig=%d\n",
status, sig));
}
} else {
TRACE(("Not printing status, rootshell=%d, job=0x%x\n", rootshell, job));
if (thisjob)
thisjob->changed = 1;
}
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(block, status)
int block;
int *status;
{
#ifdef BSD
int flags;
 
flags = 0;
#if JOBS
if (jobctl)
flags |= WUNTRACED;
#endif
if (block == 0)
flags |= WNOHANG;
return wait3(status, flags, (struct rusage *)NULL);
#else
#ifdef SYSV
int (*save)();
 
if (block == 0) {
gotsigchild = 0;
save = signal(SIGCLD, onsigchild);
signal(SIGCLD, save);
if (gotsigchild == 0)
return 0;
}
return wait(status);
#else
if (block == 0)
return 0;
return wait(status);
#endif
#endif
}
 
/*
* return 1 if there are stopped jobs, otherwise 0
*/
int job_warning = 0;
int
stoppedjobs()
{
int jobno;
struct job *jp;
 
if (job_warning)
return (0);
for (jobno = 1, jp = jobtab; jobno <= njobs; jobno++, jp++) {
if (jp->used == 0)
continue;
if (jp->state == JOBSTOPPED) {
out2str("You have stopped jobs.\n");
job_warning = 2;
return (1);
}
}
 
return (0);
}
 
/*
* Return a string identifying a command (to be printed by the
* jobs command.
*/
 
STATIC char *cmdnextc;
STATIC int cmdnleft;
#define MAXCMDTEXT 200
 
char *
commandtext(n)
union node *n;
{
char *name;
 
cmdnextc = name = ckmalloc(MAXCMDTEXT);
cmdnleft = MAXCMDTEXT - 4;
cmdtxt(n);
*cmdnextc = '\0';
return name;
}
 
 
STATIC void
cmdtxt(n)
union node *n;
{
union node *np;
struct nodelist *lp;
const char *p;
int i;
char s[2];
 
if (n == NULL)
return;
switch (n->type) {
case NSEMI:
cmdtxt(n->nbinary.ch1);
cmdputs("; ");
cmdtxt(n->nbinary.ch2);
break;
case NAND:
cmdtxt(n->nbinary.ch1);
cmdputs(" && ");
cmdtxt(n->nbinary.ch2);
break;
case NOR:
cmdtxt(n->nbinary.ch1);
cmdputs(" || ");
cmdtxt(n->nbinary.ch2);
break;
case NPIPE:
for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
cmdtxt(lp->n);
if (lp->next)
cmdputs(" | ");
}
break;
case NSUBSHELL:
cmdputs("(");
cmdtxt(n->nredir.n);
cmdputs(")");
break;
case NREDIR:
case NBACKGND:
cmdtxt(n->nredir.n);
break;
case NIF:
cmdputs("if ");
cmdtxt(n->nif.test);
cmdputs("; then ");
cmdtxt(n->nif.ifpart);
cmdputs("...");
break;
case NWHILE:
cmdputs("while ");
goto until;
case NUNTIL:
cmdputs("until ");
until:
cmdtxt(n->nbinary.ch1);
cmdputs("; do ");
cmdtxt(n->nbinary.ch2);
cmdputs("; done");
break;
case NFOR:
cmdputs("for ");
cmdputs(n->nfor.var);
cmdputs(" in ...");
break;
case NCASE:
cmdputs("case ");
cmdputs(n->ncase.expr->narg.text);
cmdputs(" in ...");
break;
case NDEFUN:
cmdputs(n->narg.text);
cmdputs("() ...");
break;
case NCMD:
for (np = n->ncmd.args ; np ; np = np->narg.next) {
cmdtxt(np);
if (np->narg.next)
cmdputs(" ");
}
for (np = n->ncmd.redirect ; np ; np = np->nfile.next) {
cmdputs(" ");
cmdtxt(np);
}
break;
case NARG:
cmdputs(n->narg.text);
break;
case NTO:
p = ">"; i = 1; goto redir;
case NAPPEND:
p = ">>"; i = 1; goto redir;
case NTOFD:
p = ">&"; i = 1; goto redir;
case NTOOV:
p = ">|"; i = 1; goto redir;
case NFROM:
p = "<"; i = 0; goto redir;
case NFROMFD:
p = "<&"; i = 0; goto redir;
case NFROMTO:
p = "<>"; i = 0; goto redir;
redir:
if (n->nfile.fd != i) {
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';
s[1] = '\0';
cmdputs(s);
} else {
cmdtxt(n->nfile.fname);
}
break;
case NHERE:
case NXHERE:
cmdputs("<<...");
break;
default:
cmdputs("???");
break;
}
}
 
 
 
STATIC void
cmdputs(s)
const char *s;
{
const char *p;
char *q;
char c;
int subtype = 0;
 
if (cmdnleft <= 0)
return;
p = s;
q = cmdnextc;
while ((c = *p++) != '\0') {
if (c == CTLESC)
*q++ = *p++;
else if (c == CTLVAR) {
*q++ = '$';
if (--cmdnleft > 0)
*q++ = '{';
subtype = *p++;
} else if (c == '=' && subtype != 0) {
*q++ = "}-+?="[(subtype & VSTYPE) - VSNORMAL];
subtype = 0;
} else if (c == CTLENDVAR) {
*q++ = '}';
} else if (c == CTLBACKQ || c == CTLBACKQ+CTLQUOTE)
cmdnleft++; /* ignore it */
else
*q++ = c;
if (--cmdnleft <= 0) {
*q++ = '.';
*q++ = '.';
*q++ = '.';
break;
}
}
cmdnextc = q;
}
 
STATIC void waitonint(int sig) {
intreceived = 1;
return;
}