/* execute tree in child subprocess */
int
exchild(struct op *t, int flags, volatile int *xerrok,
int close_fd) /* used if XPCLOSE or XCCLOSE */
{
static Proc *last_proc; /* for pipelines */
int i;
sigset_t omask;
Proc *p;
Job *j;
int rv = 0;
int forksleep;
int ischild;
if (flags & XEXEC)
/* Clear XFORK|XPCLOSE|XCCLOSE|XCOPROC|XPIPEO|XPIPEI|XXCOM|XBGND
* (also done in another execute() below)
*/
return execute(t, flags & (XEXEC | XERROK), xerrok);
/* no SIGCHLD's while messing with job and process lists */
sigprocmask(SIG_BLOCK, &sm_sigchld, &omask);
p = new_proc();
p->next = (Proc *) 0;
p->state = PRUNNING;
p->status = 0;
p->pid = 0;
/* link process into jobs list */
if (flags&XPIPEI) { /* continuing with a pipe */
if (!last_job)
internal_errorf(1,
"exchild: XPIPEI and no last_job - pid %d",
(int) procpid);
j = last_job;
last_proc->next = p;
last_proc = p;
} else {
j = new_job(); /* fills in j->job */
/* we don't consider XXCOM's foreground since they don't get
* tty process group and we don't save or restore tty modes.
*/
j->flags = (flags & XXCOM) ? JF_XXCOM :
((flags & XBGND) ? 0 : (JF_FG|JF_USETTYMODE));
timerclear(&j->usrtime);
timerclear(&j->systime);
j->state = PRUNNING;
j->pgrp = 0;
j->ppid = procpid;
j->age = ++njobs;
j->proc_list = p;
j->coproc_id = 0;
last_job = j;
last_proc = p;
put_job(j, PJ_PAST_STOPPED);
}
snptreef(p->command, sizeof(p->command), "%T", t);
/* create child process */
forksleep = 1;
while ((i = fork()) < 0 && errno == EAGAIN && forksleep < 32) {
if (intrsig) /* allow user to ^C out... */
break;
sleep(forksleep);
forksleep <<= 1;
}
if (i < 0) {
kill_job(j, SIGKILL);
remove_job(j, "fork failed");
sigprocmask(SIG_SETMASK, &omask, (sigset_t *) 0);
errorf("cannot fork - try again");
}
ischild = i == 0;
if (ischild)
p->pid = procpid = getpid();
else
p->pid = i;
#ifdef JOBS
/* job control set up */
if (Flag(FMONITOR) && !(flags&XXCOM)) {
int dotty = 0;
if (j->pgrp == 0) { /* First process */
j->pgrp = p->pid;
dotty = 1;
}
/* set pgrp in both parent and child to deal with race
* condition
*/
setpgid(p->pid, j->pgrp);
/* YYY: should this be
if (ttypgrp_ok && ischild && !(flags&XBGND))
tcsetpgrp(tty_fd, j->pgrp);
instead? (see also YYY below)
*/
if (ttypgrp_ok && dotty && !(flags & XBGND))
tcsetpgrp(tty_fd, j->pgrp);
}
#endif /* JOBS */
/* used to close pipe input fd */
if (close_fd >= 0 && (((flags & XPCLOSE) && !ischild) ||
((flags & XCCLOSE) && ischild)))
close(close_fd);
if (ischild) { /* child */
/* Do this before restoring signal */
if (flags & XCOPROC)
coproc_cleanup(false);
sigprocmask(SIG_SETMASK, &omask, (sigset_t *) 0);
cleanup_parents_env();
#ifdef JOBS
/* If FMONITOR or FTALKING is set, these signals are ignored,
* if neither FMONITOR nor FTALKING are set, the signals have
* their inherited values.
*/
if (Flag(FMONITOR) && !(flags & XXCOM)) {
for (i = NELEM(tt_sigs); --i >= 0; )
setsig(&sigtraps[tt_sigs[i]], SIG_DFL,
SS_RESTORE_DFL|SS_FORCE);
}
#endif /* JOBS */
if (Flag(FBGNICE) && (flags & XBGND))
nice(4);
if ((flags & XBGND) && !Flag(FMONITOR)) {
setsig(&sigtraps[SIGINT], SIG_IGN,
SS_RESTORE_IGN|SS_FORCE);
setsig(&sigtraps[SIGQUIT], SIG_IGN,
SS_RESTORE_IGN|SS_FORCE);
if (!(flags & (XPIPEI | XCOPROC))) {
int fd = open("/dev/null", 0);
if (fd != 0) {
(void) ksh_dup2(fd, 0, true);
close(fd);
}
}
}
remove_job(j, "child"); /* in case of `jobs` command */
nzombie = 0;
#ifdef JOBS
ttypgrp_ok = 0;
Flag(FMONITOR) = 0;
#endif /* JOBS */
Flag(FTALKING) = 0;
tty_close();
cleartraps();
execute(t, (flags & XERROK) | XEXEC, NULL); /* no return */
internal_errorf(0, "exchild: execute() returned");
unwind(LLEAVE);
/* NOTREACHED */
}
/* shell (parent) stuff */
/* Ensure next child gets a (slightly) different $RANDOM sequence */
change_random();
if (!(flags & XPIPEO)) { /* last process in a job */
#ifdef JOBS
/* YYY: Is this needed? (see also YYY above)
if (Flag(FMONITOR) && !(flags&(XXCOM|XBGND)))
tcsetpgrp(tty_fd, j->pgrp);
*/
#endif /* JOBS */
j_startjob(j);
if (flags & XCOPROC) {
j->coproc_id = coproc.id;
coproc.njobs++; /* n jobs using co-process output */
coproc.job = (void *) j; /* j using co-process input */
}
if (flags & XBGND) {
j_set_async(j);
if (Flag(FTALKING)) {
shf_fprintf(shl_out, "[%d]", j->job);
for (p = j->proc_list; p; p = p->next)
shf_fprintf(shl_out, " %d", p->pid);
shf_putchar('\n', shl_out);
shf_flush(shl_out);
}
} else
rv = j_waitj(j, JW_NONE, "jw:last proc");
}
sigprocmask(SIG_SETMASK, &omask, (sigset_t *) 0);
return rv;
}
/*
* set up redirection, saving old fds in e->savefd
*/
static int
iosetup(struct ioword *iop, struct tbl *tp)
{
int u = -1;
char *cp = iop->name;
int iotype = iop->flag & IOTYPE;
bool do_open = true, do_close = false;
int flags = 0;
struct ioword iotmp;
struct stat statb;
if (iotype != IOHERE)
cp = evalonestr(cp, DOTILDE|(Flag(FTALKING_I) ? DOGLOB : 0));
/* Used for tracing and error messages to print expanded cp */
iotmp = *iop;
iotmp.name = (iotype == IOHERE) ? NULL : cp;
iotmp.flag |= IONAMEXP;
if (Flag(FXTRACE))
shellf("%s%s\n",
substitute(str_val(global("PS4")), 0),
snptreef(NULL, 32, "%R", &iotmp));
switch (iotype) {
case IOREAD:
flags = O_RDONLY;
break;
case IOCAT:
flags = O_WRONLY | O_APPEND | O_CREAT;
break;
case IOWRITE:
flags = O_WRONLY | O_CREAT | O_TRUNC;
/*
* The stat() is here to allow redirections to
* things like /dev/null without error.
*/
if (Flag(FNOCLOBBER) && !(iop->flag & IOCLOB) &&
(stat(cp, &statb) < 0 || S_ISREG(statb.st_mode)))
flags |= O_EXCL;
break;
case IORDWR:
flags = O_RDWR | O_CREAT;
break;
case IOHERE:
do_open = false;
/* herein() returns -2 if error has been printed */
u = herein(iop, NULL);
/* cp may have wrong name */
break;
case IODUP: {
const char *emsg;
do_open = false;
if (*cp == '-' && !cp[1]) {
/* prevent error return below */
u = 1009;
do_close = true;
} else if ((u = check_fd(cp,
X_OK | ((iop->flag & IORDUP) ? R_OK : W_OK),
&emsg)) < 0) {
warningf(true, "%s: %s",
snptreef(NULL, 32, "%R", &iotmp), emsg);
return (-1);
}
if (u == iop->unit)
/* "dup from" == "dup to" */
return (0);
break;
}
}
if (do_open) {
if (Flag(FRESTRICTED) && (flags & O_CREAT)) {
warningf(true, "%s: %s", cp, "restricted");
return (-1);
}
u = open(cp, flags, 0666);
}
if (u < 0) {
/* herein() may already have printed message */
if (u == -1) {
u = errno;
warningf(true, "can't %s %s: %s",
iotype == IODUP ? "dup" :
(iotype == IOREAD || iotype == IOHERE) ?
"open" : "create", cp, cstrerror(u));
}
return (-1);
}
/* Do not save if it has already been redirected (i.e. "cat >x >y"). */
if (e->savefd[iop->unit] == 0) {
/* If these are the same, it means unit was previously closed */
if (u == iop->unit)
e->savefd[iop->unit] = -1;
else
/*
* c_exec() assumes e->savefd[fd] set for any
* redirections. Ask savefd() not to close iop->unit;
* this allows error messages to be seen if iop->unit
* is 2; also means we can't lose the fd (eg, both
* dup2 below and dup2 in restfd() failing).
*/
e->savefd[iop->unit] = savefd(iop->unit);
}
if (do_close)
close(iop->unit);
else if (u != iop->unit) {
if (ksh_dup2(u, iop->unit, true) < 0) {
int eno;
eno = errno;
warningf(true, "%s %s %s",
"can't finish (dup) redirection",
snptreef(NULL, 32, "%R", &iotmp),
cstrerror(eno));
if (iotype != IODUP)
close(u);
return (-1);
}
if (iotype != IODUP)
close(u);
/*
* Touching any co-process fd in an empty exec
* causes the shell to close its copies
*/
else if (tp && tp->type == CSHELL && tp->val.f == c_exec) {
if (iop->flag & IORDUP)
/* possible exec <&p */
coproc_read_close(u);
else
/* possible exec >&p */
coproc_write_close(u);
}
}
if (u == 2)
/* Clear any write errors */
shf_reopen(2, SHF_WR, shl_out);
return (0);
}
int
exchild(struct op *t, int flags,
int close_fd) /* used if XPCLOSE or XCCLOSE */
{
static Proc *last_proc; /* for pipelines */
int i;
sigset_t omask;
Proc *p;
Job *j;
int rv = 0;
int forksleep;
int ischild;
if (flags & XEXEC)
/* Clear XFORK|XPCLOSE|XCCLOSE|XCOPROC|XPIPEO|XPIPEI|XXCOM|XBGND
* (also done in another execute() below)
*/
return execute(t, flags & (XEXEC | XERROK));
p = new_proc();
p->next = (Proc *) 0;
p->state = PRUNNING;
p->status = 0;
p->pid = 0;
/* link process into jobs list */
if (flags&XPIPEI) { /* continuing with a pipe */
if (!last_job)
internal_errorf(1,
"exchild: XPIPEI and no last_job - pid %d",
(int) procpid);
j = last_job;
last_proc->next = p;
last_proc = p;
} else {
j = new_job(); /* fills in j->job */
/* we don't consider XXCOM's foreground since they don't get
* tty process group and we don't save or restore tty modes.
*/
j->flags = (flags & XXCOM) ? JF_XXCOM :
((flags & XBGND) ? 0 : (JF_FG|JF_USETTYMODE));
j->usrtime = j->systime = 0;
j->state = PRUNNING;
j->pgrp = 0;
j->ppid = procpid;
j->age = ++njobs;
j->proc_list = p;
j->coproc_id = 0;
last_job = j;
last_proc = p;
put_job(j, PJ_PAST_STOPPED);
}
snptreef(p->command, sizeof(p->command), "%T", t);
/* create child process */
forksleep = 1;
while ((i = fork()) < 0 && errno == EAGAIN && forksleep < 32) {
if (intrsig) /* allow user to ^C out... */
break;
sleep(forksleep);
forksleep <<= 1;
}
if (i < 0) {
kill_job(j, SIGKILL);
remove_job(j, "fork failed");
sigprocmask(SIG_SETMASK, &omask, (sigset_t *) 0);
errorf("cannot fork - try again");
}
ischild = i == 0;
if (ischild)
p->pid = procpid = getpid();
else
p->pid = i;
/* used to close pipe input fd */
if (close_fd >= 0 && (((flags & XPCLOSE) && !ischild) ||
((flags & XCCLOSE) && ischild)))
close(close_fd);
if (ischild) { /* child */
/* Do this before restoring signal */
if (flags & XCOPROC)
coproc_cleanup(false);
sigprocmask(SIG_SETMASK, &omask, (sigset_t *) 0);
cleanup_parents_env();
if ((flags & XBGND)) {
setsig(&sigtraps[SIGINT], SIG_IGN,
SS_RESTORE_IGN|SS_FORCE);
setsig(&sigtraps[SIGQUIT], SIG_IGN,
SS_RESTORE_IGN|SS_FORCE);
if (!(flags & (XPIPEI | XCOPROC))) {
int fd = open("/dev/null", 0);
if (fd != 0) {
(void) ksh_dup2(fd, 0, true);
close(fd);
}
}
}
remove_job(j, "child"); /* in case of `jobs` command */
nzombie = 0;
Flag(FTALKING) = 0;
tty_close();
cleartraps();
execute(t, (flags & XERROK) | XEXEC); /* no return */
internal_errorf(0, "exchild: execute() returned");
unwind(LLEAVE);
/* NOTREACHED */
}
/* shell (parent) stuff */
/* Ensure next child gets a (slightly) different $RANDOM sequence */
change_random();
if (!(flags & XPIPEO)) { /* last process in a job */
j_startjob(j);
if (flags & XCOPROC) {
j->coproc_id = coproc.id;
coproc.njobs++; /* n jobs using co-process output */
coproc.job = (void *) j; /* j using co-process input */
}
if (flags & XBGND) {
j_set_async(j);
if (Flag(FTALKING)) {
shf_fprintf(shl_out, "[%d]", j->job);
for (p = j->proc_list; p; p = p->next)
shf_fprintf(shl_out, " %d", p->pid);
shf_putchar('\n', shl_out);
shf_flush(shl_out);
}
} else
rv = j_waitj(j, JW_NONE, "jw:last proc");
}
sigprocmask(SIG_SETMASK, &omask, (sigset_t *) 0);
return rv;
}
